Emotion Separation Is Completed Early and It Depends on Visual Field Presentation

PubMed Central

Liu, Lichan; Ioannides, Andreas A.

2010-01-01

It is now apparent that the visual system reacts to stimuli very fast, with many brain areas activated within 100 ms. It is, however, unclear how much detail is extracted about stimulus properties in the early stages of visual processing. Here, using magnetoencephalography we show that the visual system separates different facial expressions of emotion well within 100 ms after image onset, and that this separation is processed differently depending on where in the visual field the stimulus is presented. Seven right-handed males participated in a face affect recognition experiment in which they viewed happy, fearful and neutral faces. Blocks of images were shown either at the center or in one of the four quadrants of the visual field. For centrally presented faces, the emotions were separated fast, first in the right superior temporal sulcus (STS; 35–48 ms), followed by the right amygdala (57–64 ms) and medial pre-frontal cortex (83–96 ms). For faces presented in the periphery, the emotions were separated first in the ipsilateral amygdala and contralateral STS. We conclude that amygdala and STS likely play a different role in early visual processing, recruiting distinct neural networks for action: the amygdala alerts sub-cortical centers for appropriate autonomic system response for fight or flight decisions, while the STS facilitates more cognitive appraisal of situations and links appropriate cortical sites together. It is then likely that different problems may arise when either network fails to initiate or function properly. PMID:20339549

Contralateral Bias of High Spatial Frequency Tuning and Cardinal Direction Selectivity in Mouse Visual Cortex

PubMed Central

Zeitoun, Jack H.; Kim, Hyungtae

2017-01-01

Binocular mechanisms for visual processing are thought to enhance spatial acuity by combining matched input from the two eyes. Studies in the primary visual cortex of carnivores and primates have confirmed that eye-specific neuronal response properties are largely matched. In recent years, the mouse has emerged as a prominent model for binocular visual processing, yet little is known about the spatial frequency tuning of binocular responses in mouse visual cortex. Using calcium imaging in awake mice of both sexes, we show that the spatial frequency preference of cortical responses to the contralateral eye is ∼35% higher than responses to the ipsilateral eye. Furthermore, we find that neurons in binocular visual cortex that respond only to the contralateral eye are tuned to higher spatial frequencies. Binocular neurons that are well matched in spatial frequency preference are also matched in orientation preference. In contrast, we observe that binocularly mismatched cells are more mismatched in orientation tuning. Furthermore, we find that contralateral responses are more direction-selective than ipsilateral responses and are strongly biased to the cardinal directions. The contralateral bias of high spatial frequency tuning was found in both awake and anesthetized recordings. The distinct properties of contralateral cortical responses may reflect the functional segregation of direction-selective, high spatial frequency-preferring neurons in earlier stages of the central visual pathway. Moreover, these results suggest that the development of binocularity and visual acuity may engage distinct circuits in the mouse visual system. SIGNIFICANCE STATEMENT Seeing through two eyes is thought to improve visual acuity by enhancing sensitivity to fine edges. Using calcium imaging of cellular responses in awake mice, we find surprising asymmetries in the spatial processing of eye-specific visual input in binocular primary visual cortex. The contralateral visual pathway is tuned to higher spatial frequencies than the ipsilateral pathway. At the highest spatial frequencies, the contralateral pathway strongly prefers to respond to visual stimuli along the cardinal (horizontal and vertical) axes. These results suggest that monocular, and not binocular, mechanisms set the limit of spatial acuity in mice. Furthermore, they suggest that the development of visual acuity and binocularity in mice involves different circuits. PMID:28924011

The Occipital Face Area Is Causally Involved in Facial Viewpoint Perception

PubMed Central

Poltoratski, Sonia; König, Peter; Blake, Randolph; Tong, Frank; Ling, Sam

2015-01-01

Humans reliably recognize faces across a range of viewpoints, but the neural substrates supporting this ability remain unclear. Recent work suggests that neural selectivity to mirror-symmetric viewpoints of faces, found across a large network of visual areas, may constitute a key computational step in achieving full viewpoint invariance. In this study, we used repetitive transcranial magnetic stimulation (rTMS) to test the hypothesis that the occipital face area (OFA), putatively a key node in the face network, plays a causal role in face viewpoint symmetry perception. Each participant underwent both offline rTMS to the right OFA and sham stimulation, preceding blocks of behavioral trials. After each stimulation period, the participant performed one of two behavioral tasks involving presentation of faces in the peripheral visual field: (1) judging the viewpoint symmetry; or (2) judging the angular rotation. rTMS applied to the right OFA significantly impaired performance in both tasks when stimuli were presented in the contralateral, left visual field. Interestingly, however, rTMS had a differential effect on the two tasks performed ipsilaterally. Although viewpoint symmetry judgments were significantly disrupted, we observed no effect on the angle judgment task. This interaction, caused by ipsilateral rTMS, provides support for models emphasizing the role of interhemispheric crosstalk in the formation of viewpoint-invariant face perception. SIGNIFICANCE STATEMENT Faces are among the most salient objects we encounter during our everyday activities. Moreover, we are remarkably adept at identifying people at a glance, despite the diversity of viewpoints during our social encounters. Here, we investigate the cortical mechanisms underlying this ability by focusing on effects of viewpoint symmetry, i.e., the invariance of neural responses to mirror-symmetric facial viewpoints. We did this by temporarily disrupting neural processing in the occipital face area (OFA) using transcranial magnetic stimulation. Our results demonstrate that the OFA causally contributes to judgments facial viewpoints and suggest that effects of viewpoint symmetry, previously observed using fMRI, arise from an interhemispheric integration of visual information even when only one hemisphere receives direct visual stimulation. PMID:26674865

The Occipital Face Area Is Causally Involved in Facial Viewpoint Perception.

PubMed

Kietzmann, Tim C; Poltoratski, Sonia; König, Peter; Blake, Randolph; Tong, Frank; Ling, Sam

2015-12-16

Humans reliably recognize faces across a range of viewpoints, but the neural substrates supporting this ability remain unclear. Recent work suggests that neural selectivity to mirror-symmetric viewpoints of faces, found across a large network of visual areas, may constitute a key computational step in achieving full viewpoint invariance. In this study, we used repetitive transcranial magnetic stimulation (rTMS) to test the hypothesis that the occipital face area (OFA), putatively a key node in the face network, plays a causal role in face viewpoint symmetry perception. Each participant underwent both offline rTMS to the right OFA and sham stimulation, preceding blocks of behavioral trials. After each stimulation period, the participant performed one of two behavioral tasks involving presentation of faces in the peripheral visual field: (1) judging the viewpoint symmetry; or (2) judging the angular rotation. rTMS applied to the right OFA significantly impaired performance in both tasks when stimuli were presented in the contralateral, left visual field. Interestingly, however, rTMS had a differential effect on the two tasks performed ipsilaterally. Although viewpoint symmetry judgments were significantly disrupted, we observed no effect on the angle judgment task. This interaction, caused by ipsilateral rTMS, provides support for models emphasizing the role of interhemispheric crosstalk in the formation of viewpoint-invariant face perception. Faces are among the most salient objects we encounter during our everyday activities. Moreover, we are remarkably adept at identifying people at a glance, despite the diversity of viewpoints during our social encounters. Here, we investigate the cortical mechanisms underlying this ability by focusing on effects of viewpoint symmetry, i.e., the invariance of neural responses to mirror-symmetric facial viewpoints. We did this by temporarily disrupting neural processing in the occipital face area (OFA) using transcranial magnetic stimulation. Our results demonstrate that the OFA causally contributes to judgments facial viewpoints and suggest that effects of viewpoint symmetry, previously observed using fMRI, arise from an interhemispheric integration of visual information even when only one hemisphere receives direct visual stimulation. Copyright © 2015 the authors 0270-6474/15/3516398-06$15.00/0.

Effect of task set-modulating attentional capture depends on the distractor cost in visual search: evidence from N2pc.

PubMed

Zhao, Dandan; Liang, Shengnan; Jin, Zhenlan; Li, Ling

2014-07-09

Previous studies have confirmed that attention can be modulated by the current task set while involuntarily captured by salient items. However, little is known on which factors the modulation of attentional capture is dependent on when the same stimuli with different task sets are presented. In the present study, participants conducted two visual search tasks with the same search arrays by varying target and distractor settings (color singleton as target, onset singleton as distractor, named as color task, and vice versa). Ipsilateral and contralateral color distractors resulted in two different relative saliences in two tasks, respectively. Both reaction times (RTs) and N2-posterior-contralateral (N2pc) results showed that there was no difference between ipsilateral and contralateral color distractors in the onset task. However, both RTs and the latency of N2pc showed a delay to the ipsilateral onset distractor compared with the contralateral onset distractor. Moreover, the N2pc observed under the contralateral distractor condition in the color task was reversed, and its amplitude was attenuated. On the basis of these results, we proposed a parameter called distractor cost (DC), computed by subtracting RTs under the contralateral distractor condition from the ipsilateral condition. The results suggest that an enhanced DC might be related to the modification of N2pc in searching for the color target. Taken together, these findings provide evidence that the effect of task set-modulating attentional capture in visual search is related to the DC.

Asymmetrical Interhemispheric Connections Develop in Cat Visual Cortex after Early Unilateral Convergent Strabismus: Anatomy, Physiology, and Mechanisms

PubMed Central

Bui Quoc, Emmanuel; Ribot, Jérôme; Quenech’Du, Nicole; Doutremer, Suzette; Lebas, Nicolas; Grantyn, Alexej; Aushana, Yonane; Milleret, Chantal

2011-01-01

In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When this is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, data concerning these changes are sparse and incomplete. Thus, little is known about the impact of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience) were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non-deviated eye). Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute successively to the development of the callosal maps in visual cortex. PMID:22275883

Visual Working Memory Load-Related Changes in Neural Activity and Functional Connectivity

PubMed Central

Li, Ling; Zhang, Jin-Xiang; Jiang, Tao

2011-01-01

Background Visual working memory (VWM) helps us store visual information to prepare for subsequent behavior. The neuronal mechanisms for sustaining coherent visual information and the mechanisms for limited VWM capacity have remained uncharacterized. Although numerous studies have utilized behavioral accuracy, neural activity, and connectivity to explore the mechanism of VWM retention, little is known about the load-related changes in functional connectivity for hemi-field VWM retention. Methodology/Principal Findings In this study, we recorded electroencephalography (EEG) from 14 normal young adults while they performed a bilateral visual field memory task. Subjects had more rapid and accurate responses to the left visual field (LVF) memory condition. The difference in mean amplitude between the ipsilateral and contralateral event-related potential (ERP) at parietal-occipital electrodes in retention interval period was obtained with six different memory loads. Functional connectivity between 128 scalp regions was measured by EEG phase synchronization in the theta- (4–8 Hz), alpha- (8–12 Hz), beta- (12–32 Hz), and gamma- (32–40 Hz) frequency bands. The resulting matrices were converted to graphs, and mean degree, clustering coefficient and shortest path length was computed as a function of memory load. The results showed that brain networks of theta-, alpha-, beta-, and gamma- frequency bands were load-dependent and visual-field dependent. The networks of theta- and alpha- bands phase synchrony were most predominant in retention period for right visual field (RVF) WM than for LVF WM. Furthermore, only for RVF memory condition, brain network density of theta-band during the retention interval were linked to the delay of behavior reaction time, and the topological property of alpha-band network was negative correlation with behavior accuracy. Conclusions/Significance We suggest that the differences in theta- and alpha- bands between LVF and RVF conditions in functional connectivity and topological properties during retention period may result in the decline of behavioral performance in RVF task. PMID:21789253

Ten-m3 Is Required for the Development of Topography in the Ipsilateral Retinocollicular Pathway

PubMed Central

Dharmaratne, Nuwan; Glendining, Kelly A.; Young, Timothy R.; Tran, Heidi; Sawatari, Atomu; Leamey, Catherine A.

2012-01-01

Background The alignment of ipsilaterally and contralaterally projecting retinal axons that view the same part of visual space is fundamental to binocular vision. While much progress has been made regarding the mechanisms which regulate contralateral topography, very little is known of the mechanisms which regulate the mapping of ipsilateral axons such that they align with their contralateral counterparts. Results Using the advantageous model provided by the mouse retinocollicular pathway, we have performed anterograde tracing experiments which demonstrate that ipsilateral retinal axons begin to form terminal zones (TZs) in the superior colliculus (SC), within the first few postnatal days. These appear mature by postnatal day 11. Importantly, TZs formed by ipsilaterally-projecting retinal axons are spatially offset from those of contralaterally-projecting axons arising from the same retinotopic location from the outset. This pattern is consistent with that required for adult visuotopy. We further demonstrate that a member of the Ten-m/Odz/Teneurin family of homophilic transmembrane glycoproteins, Ten-m3, is an essential regulator of ipsilateral retinocollicular topography. Ten-m3 mRNA is expressed in a high-medial to low-lateral gradient in the developing SC. This corresponds topographically with its high-ventral to low-dorsal retinal gradient. In Ten-m3 knockout mice, contralateral ventrotemporal axons appropriately target rostromedial SC, whereas ipsilateral axons exhibit dramatic targeting errors along both the mediolateral and rostrocaudal axes of the SC, with a caudal shift of the primary TZ, as well as the formation of secondary, caudolaterally displaced TZs. In addition to these dramatic ipsilateral-specific mapping errors, both contralateral and ipsilateral retinocollicular TZs exhibit more subtle changes in morphology. Conclusions We conclude that important aspects of adult visuotopy are established via the differential sensitivity of ipsilateral and contralateral axons to intrinsic guidance cues. Further, we show that Ten-m3 plays a critical role in this process and is particularly important for the mapping of the ipsilateral retinocollicular pathway. PMID:23028443

Morning Glory Syndrome with Carotid and Middle Cerebral Artery Vasculopathy.

PubMed

Nezzar, Hachemi; Mbekeani, Joyce N; Dalens, Helen

2015-12-01

To report a case of incidental asymptomatic atypical morning glory syndrome (MGS) with concomitant ipsilateral carotid and middle cerebral dysgenesis. A 6-year-old child was discovered to have incidental findings of MGS, with atypia. All visual functions were normal including vision and stereopsis. Neuroimaging revealed ipsilateral carotid and middle cerebral vascular narrowing without associated collateral vessels or cerebral ischemia commonly seen in Moyamoya disease. Subsequent annual examinations have been stable, without signs of progression. This case demonstrates disparity between structural aberrations and final visual and neurological function and reinforces the association between MGS and intracranial vascular disruption. Full ancillary ophthalmic and neuroimaging studies should be performed in all patients with MGS with interval reassessments, even when the patient is asymptomatic and functionally intact.

Miniopen Transforaminal Lumbar Interbody Fusion with Unilateral Fixation: A Comparison between Ipsilateral and Contralateral Reherniation

PubMed Central

Liu, Fubing; Jiang, Chun

2016-01-01

The aim of this study was to evaluate the risk factors between ipsilateral and contralateral reherniation and to compare the effectiveness of miniopen transforaminal lumbar interbody fusion (TLIF) with unilateral fixation for each group. From November 2007 to December 2014, clinical and radiographic data of each group (ipsilateral or contralateral reherniation) were collected and compared. Functional assessment (Visual Analog Scale (VAS) score and Japanese Orthopaedic Association (JOA)) and radiographic evaluation (fusion status, disc height, lumbar lordosis (LL), and functional spine unit (FSU) angle) were applied to compare surgical effect for each group preoperatively and at final followup. MacNab questionnaire was applied to further evaluate the satisfactory rate after the discectomy and fusion. No difference except pain-free interval was found between ipsilateral and contralateral groups. There was a significant difference in operative time between two groups. No differences were found in clinical and radiographic data for assessment of surgical effect between two groups. The satisfactory rate was decreasing in both groups with time passing after discectomy. Difference in pain-free interval may be a distinction for ipsilateral and contralateral reherniation. Miniopen TLIF with unilateral pedicle screw fixation can be a recommendable way for single level reherniation regardless of ipsilateral or contralateral reherniation. PMID:27885358

Visual area of the lateral suprasylvian gyrus (Clare—Bishop area) of the cat

PubMed Central

Hubel, David H.; Wiesel, Torsten N.

1969-01-01

On anatomical and physiological grounds a zone of cat cortex deep in the medial bank of the suprasylvian sulcus (the Clare—Bishop area) is known to receive strong visual projections both from the lateral geniculate body and area 17. We have mapped receptive fields of single cells in this area in eight cats. Active responses to visual stimuli were found over most of the medial bank of the suprasylvian sulcus extending to the depths and over to the lowest part of the lateral bank. The area is clearly topographically arranged. The first responsive cells, recorded over the lateral convexity and 2-3 mm down the medial bank, had receptive fields in the far periphery of the contralateral visual fields. The receptive fields tended to be large, but showed considerable variation in size and scatter in their positions. As the electrode advanced down the bank, fields of successively recorded cells gradually tended to move inwards, so that in the depths of the sulcus the inner borders of many of the fields reached the vertical mid line. Here the fields were smaller, though they still varied very much in size. Receptive fields were larger than in 17, 18, or 19, but otherwise were not obviously different from the complex and lower-order hypercomplex fields in those areas. No simple fields, or concentric fields of the retino-geniculate type, were seen. Cells with common receptive-field orientation were grouped together, but whether or not the grouping occurs in columns was not established. Most cells were driven independently by the two eyes. Fields in the two eyes seemed to be identical in organization. Cells dominated by the contralateral eye were much more common than ipsilaterally dominated ones, but when cells with parafoveal and peripheral fields were considered separately, the asymmetry was seen to apply mainly to cells with peripheral fields. PMID:5770897

[Occipital neuralgia with visual obscurations: a case report].

PubMed

Selekler, Hamit Macit; Dündar, Gülmine; Kutlu, Ayşe

2010-07-01

Vertigo, dizziness and visual blurring have been reported in painful conditions in trigeminal innervation zones such as in idiopathic stabbing headache, supraorbital neuralgia or trigeminal nerve ophthalmic branch neuralgia. Although not common, pain in occipital neuralgia can spread through the anterior parts of the head. In this article, we present a case whose occipital neuralgiform paroxysms spread to the ipsilateral eye with simultaneous visual obscuration; the mechanisms of propagation and visual obscuration are discussed.

Retinotopic Maps, Spatial Tuning, and Locations of Human Visual Areas in Surface Coordinates Characterized with Multifocal and Blocked fMRI Designs

PubMed Central

Henriksson, Linda; Karvonen, Juha; Salminen-Vaparanta, Niina; Railo, Henry; Vanni, Simo

2012-01-01

The localization of visual areas in the human cortex is typically based on mapping the retinotopic organization with functional magnetic resonance imaging (fMRI). The most common approach is to encode the response phase for a slowly moving visual stimulus and to present the result on an individual's reconstructed cortical surface. The main aims of this study were to develop complementary general linear model (GLM)-based retinotopic mapping methods and to characterize the inter-individual variability of the visual area positions on the cortical surface. We studied 15 subjects with two methods: a 24-region multifocal checkerboard stimulus and a blocked presentation of object stimuli at different visual field locations. The retinotopic maps were based on weighted averaging of the GLM parameter estimates for the stimulus regions. In addition to localizing visual areas, both methods could be used to localize multiple retinotopic regions-of-interest. The two methods yielded consistent retinotopic maps in the visual areas V1, V2, V3, hV4, and V3AB. In the higher-level areas IPS0, VO1, LO1, LO2, TO1, and TO2, retinotopy could only be mapped with the blocked stimulus presentation. The gradual widening of spatial tuning and an increase in the responses to stimuli in the ipsilateral visual field along the hierarchy of visual areas likely reflected the increase in the average receptive field size. Finally, after registration to Freesurfer's surface-based atlas of the human cerebral cortex, we calculated the mean and variability of the visual area positions in the spherical surface-based coordinate system and generated probability maps of the visual areas on the average cortical surface. The inter-individual variability in the area locations decreased when the midpoints were calculated along the spherical cortical surface compared with volumetric coordinates. These results can facilitate both analysis of individual functional anatomy and comparisons of visual cortex topology across studies. PMID:22590626

Topographic contribution of early visual cortex to short-term memory consolidation: a transcranial magnetic stimulation study.

PubMed

van de Ven, Vincent; Jacobs, Christianne; Sack, Alexander T

2012-01-04

The neural correlates for retention of visual information in visual short-term memory are considered separate from those of sensory encoding. However, recent findings suggest that sensory areas may play a role also in short-term memory. We investigated the functional relevance, spatial specificity, and temporal characteristics of human early visual cortex in the consolidation of capacity-limited topographic visual memory using transcranial magnetic stimulation (TMS). Topographically specific TMS pulses were delivered over lateralized occipital cortex at 100, 200, or 400 ms into the retention phase of a modified change detection task with low or high memory loads. For the high but not the low memory load, we found decreased memory performance for memory trials in the visual field contralateral, but not ipsilateral to the side of TMS, when pulses were delivered at 200 ms into the retention interval. A behavioral version of the TMS experiment, in which a distractor stimulus (memory mask) replaced the TMS pulses, further corroborated these findings. Our findings suggest that retinotopic visual cortex contributes to the short-term consolidation of topographic visual memory during early stages of the retention of visual information. Further, TMS-induced interference decreased the strength (amplitude) of the memory representation, which most strongly affected the high memory load trials.

Dendro-dendritic interactions between motion-sensitive large-field neurons in the fly.

PubMed

Haag, Juergen; Borst, Alexander

2002-04-15

For visual course control, flies rely on a set of motion-sensitive neurons called lobula plate tangential cells (LPTCs). Among these cells, the so-called CH (centrifugal horizontal) cells shape by their inhibitory action the receptive field properties of other LPTCs called FD (figure detection) cells specialized for figure-ground discrimination based on relative motion. Studying the ipsilateral input circuitry of CH cells by means of dual-electrode and combined electrical-optical recordings, we find that CH cells receive graded input from HS (large-field horizontal system) cells via dendro-dendritic electrical synapses. This particular wiring scheme leads to a spatial blur of the motion image on the CH cell dendrite, and, after inhibiting FD cells, to an enhancement of motion contrast. This could be crucial for enabling FD cells to discriminate object from self motion.

Area 21a of cat visual cortex strongly modulates neuronal activities in the superior colliculus

PubMed Central

Hashemi-Nezhad, M; Wang, C; Burke, W; Dreher, B

2003-01-01

We have examined the influence of cortico-tectal projections from one of the pattern-processing extrastriate visual cortical areas, area 21a, on the responses to visual stimuli of single neurones in the superior colliculi of adult cats. For this purpose area 21a was briefly inactivated by cooling to 10 °C using a Peltier device. Responses to visual stimuli before and during cooling as well as after rewarming ipsilateral area 21a were compared. In addition, in a subpopulation of collicular neurones we have studied the effects of reversible inactivation of ipsilateral striate cortex (area 17, area V1). When area 21a was cooled, the temperature of area 17 was kept at 36 °C and vice versa. In the majority of cases (41/65; 63 %), irrespective of the velocity response profiles of collicular neurones, inactivation of area 21a resulted in a significant decrease in magnitude of responses of neurones in the ipsilateral colliculus and only in a small proportion of cells (2/65; 3.1 %) was there a significant increase in the magnitude of responses. Inactivation of area 21a resulted in significant changes in the magnitude of responses of collicular cells located not only in the retino-recipient layers but also in the stratum griseum intermediale. In most cases, reversible inactivation of area 17 resulted in a greater reduction in the magnitude of responses of collicular cells than inactivation of area 21a. Reversible inactivation of area 21a also affected the direction selectivity indices and length tuning of most collicular cells tested. PMID:12794178

The differential effects of acute right- vs. left-sided vestibular failure on brain metabolism.

PubMed

Becker-Bense, Sandra; Dieterich, Marianne; Buchholz, Hans-Georg; Bartenstein, Peter; Schreckenberger, Mathias; Brandt, Thomas

2014-07-01

The human vestibular system is represented in the brain bilaterally, but it has functional asymmetries, i.e., a dominance of ipsilateral pathways and of the right hemisphere in right-handers. To determine if acute right- or left-sided unilateral vestibular neuritis (VN) is associated with differential patterns of brain metabolism in areas representing the vestibular network and the visual-vestibular interaction, patients with acute VN (right n = 9; left n = 13) underwent resting state (18)F-FDG PET once in the acute phase and once 3 months later after central vestibular compensation. The contrast acute vs. chronic phase showed signal differences in contralateral vestibular areas and the inverse contrast in visual cortex areas, both more pronounced in VN right. In VN left additional regions were found in the cerebellar hemispheres and vermis bilaterally, accentuated in severe cases. In general, signal changes appeared more pronounced in patients with more severe vestibular deficits. Acute phase PET data of patients compared to that of age-matched healthy controls disclosed similarities to these patterns, thus permitting the interpretation that the signal changes in vestibular temporo-parietal areas reflect signal increases, and in visual areas, signal decreases. These data imply that brain activity in the acute phase of right- and left-sided VN exhibits different compensatory patterns, i.e., the dominant ascending input is shifted from the ipsilateral to the contralateral pathways, presumably due to the missing ipsilateral vestibular input. The visual-vestibular interaction patterns were preserved, but were of different prominence in each hemisphere and more pronounced in patients with right-sided failure and more severe vestibular deficits.

The electrophysiology of thyroid surgery: electrophysiologic and muscular responses with stimulation of the vagus nerve, recurrent laryngeal nerve, and external branch of the superior laryngeal nerve.

PubMed

Liddy, Whitney; Barber, Samuel R; Cinquepalmi, Matteo; Lin, Brian M; Patricio, Stephanie; Kyriazidis, Natalia; Bellotti, Carlo; Kamani, Dipti; Mahamad, Sadhana; Dralle, Henning; Schneider, Rick; Dionigi, Gianlorenzo; Barczynski, Marcin; Wu, Che-Wei; Chiang, Feng Yu; Randolph, Gregory

2017-03-01

Correlation of physiologically important electromyographic (EMG) waveforms with demonstrable muscle activation is important for the reliable interpretation of evoked waveforms during intraoperative neural monitoring (IONM) of the vagus nerve, recurrent laryngeal nerve (RLN), and external branch of the superior laryngeal nerve (EBSLN) in thyroid surgery. Retrospective chart review. Data were reviewed retrospectively for thyroid surgery patients with laryngeal nerve IONM from January to December, 2015. EMG responses to monopolar stimulation of the vagus/RLN and EBSLN were recorded in bilateral vocalis, cricothyroid (CTM), and strap muscles using endotracheal tube-based surface and intramuscular hook electrodes, respectively. Target muscles for vagal/RLN and EBSLN stimulation were the ipsilateral vocalis and CTM, respectively. All other recording channels were nontarget muscles. Fifty surgical sides were identified in 37 subjects. All target muscle mean amplitudes were significantly higher than in nontarget muscles. With vagal/RLN stimulation, target ipsilateral vocalis mean amplitude was 1,095.7 μV (mean difference range = -814.1 to -1,078 μV, P < .0001). For EBSLN stimulation, target ipsilateral CTM mean amplitude was 6,379.3 μV (mean difference range = -6,222.6 to -6,362.3 μV, P < .0001). Target muscle large-amplitude EMG responses correlated with meaningful visual or palpable muscular responses, whereas nontarget EMG responses showed no meaningful muscle activation. Target and nontarget laryngeal muscles are differentiated based on divergence of EMG response directly correlating with presence or absence of visual and palpable muscle activation. Low-amplitude EMG waveforms in nontarget muscles with neural stimulation can be explained by the concept of far-field artifactual waveforms and do not correspond to a true muscular response. The surgeon should be aware of these nonphysiologic waveforms when interpreting and applying IONM during thyroid surgery. 4 Laryngoscope, 127:764-771, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Lateral supraorbital approach to ipsilateral PCA-P1 and ICA-PCoA aneurysms.

PubMed

Goehre, Felix; Jahromi, Behnam Rezai; Elsharkawy, Ahmed; Lehto, Hanna; Shekhtman, Oleg; Andrade-Barazarte, Hugo; Munoz, Francisco; Hijazy, Ferzat; Makhkamov, Makhkam; Hernesniemi, Juha

2015-01-01

Aneurysms of the posterior cerebral artery (PCA) are rare and often associated with anterior circulation aneurysms. The lateral supraorbital approach allows for a very fast and safe approach to the ipsilateral lesions Circle of Willis. A technical note on the successful clip occlusion of two aneurysms in the anterior and posterior Circle of Willis via this less invasive approach has not been published before. The objective of this technical note is to describe the simultaneous microsurgical clip occlusion of an ipsilateral PCA-P1 and an internal carotid artery - posterior communicating artery (ICA-PCoA) aneurysm via the lateral supraorbital approach. The authors present a technical report of successful clip occlusions of ipsilateral located PCA-P1 and ICA-PCoA aneurysms. A 59-year-old female patient was diagnosed with a PCA-P1 and an ipsilateral ICA-PCoA aneurysm by computed tomography angiography (CTA) after an ischemic stroke secondary to a contralateral ICA dissection. The patient underwent microsurgical clipping after a lateral supraorbital craniotomy. The intraoperative indocyanine green (ICG) videoangiography and the postoperative CTA showed a complete occlusion of both aneurysms; the parent vessels (ICA and PCA) were patent. The patient presents postoperative no new neurologic deficit. The lateral supraorbital approach is suitable for the simultaneous microsurgical treatment of proximal anterior circulation and ipsilateral proximal PCA aneurysms. Compared to endovascular treatment, direct visual control of brainstem perforators is possible.

Cortical metabolic activity matches the pattern of visual suppression in strabismus.

PubMed

Adams, Daniel L; Economides, John R; Sincich, Lawrence C; Horton, Jonathan C

2013-02-27

When an eye becomes deviated in early childhood, a person does not experience double vision, although the globes are aimed at different targets. The extra image is prevented from reaching perception in subjects with alternating exotropia by suppression of each eye's peripheral temporal retina. To test the impact of visual suppression on neuronal activity in primary (striate) visual cortex, the pattern of cytochrome oxidase (CO) staining was examined in four macaques raised with exotropia by disinserting the medial rectus muscles shortly following birth. No ocular dominance columns were visible in opercular cortex, where the central visual field is represented, indicating that signals coming from the central retina in each eye were perceived. However, the border strips at the edges of ocular dominance columns appeared pale, reflecting a loss of activity in binocular cells from disruption of fusion. In calcarine cortex, where the peripheral visual field is represented, there were alternating pale and dark bands resembling ocular dominance columns. To interpret the CO staining pattern, [(3)H]proline was injected into the right eye in two monkeys. In the right calcarine cortex, the pale CO columns matched the labeled proline columns of the right eye. In the left calcarine cortex, the pale CO columns overlapped the unlabeled columns of the left eye in the autoradiograph. Therefore, metabolic activity was reduced in the ipsilateral eye's ocular dominance columns which serve peripheral temporal retina, in a fashion consistent with the topographic organization of suppression scotomas in humans with exotropia.

Lateral supraorbital approach to ipsilateral PCA-P1 and ICA-PCoA aneurysms

PubMed Central

Goehre, Felix; Jahromi, Behnam Rezai; Elsharkawy, Ahmed; Lehto, Hanna; Shekhtman, Oleg; Andrade-Barazarte, Hugo; Munoz, Francisco; Hijazy, Ferzat; Makhkamov, Makhkam; Hernesniemi, Juha

2015-01-01

Background: Aneurysms of the posterior cerebral artery (PCA) are rare and often associated with anterior circulation aneurysms. The lateral supraorbital approach allows for a very fast and safe approach to the ipsilateral lesions Circle of Willis. A technical note on the successful clip occlusion of two aneurysms in the anterior and posterior Circle of Willis via this less invasive approach has not been published before. The objective of this technical note is to describe the simultaneous microsurgical clip occlusion of an ipsilateral PCA-P1 and an internal carotid artery - posterior communicating artery (ICA-PCoA) aneurysm via the lateral supraorbital approach. Case Description: The authors present a technical report of successful clip occlusions of ipsilateral located PCA-P1 and ICA-PCoA aneurysms. A 59-year-old female patient was diagnosed with a PCA-P1 and an ipsilateral ICA-PCoA aneurysm by computed tomography angiography (CTA) after an ischemic stroke secondary to a contralateral ICA dissection. The patient underwent microsurgical clipping after a lateral supraorbital craniotomy. The intraoperative indocyanine green (ICG) videoangiography and the postoperative CTA showed a complete occlusion of both aneurysms; the parent vessels (ICA and PCA) were patent. The patient presents postoperative no new neurologic deficit. Conclusion: The lateral supraorbital approach is suitable for the simultaneous microsurgical treatment of proximal anterior circulation and ipsilateral proximal PCA aneurysms. Compared to endovascular treatment, direct visual control of brainstem perforators is possible. PMID:26060600

Enhancement of vision by monocular deprivation in adult mice.

PubMed

Prusky, Glen T; Alam, Nazia M; Douglas, Robert M

2006-11-08

Plasticity of vision mediated through binocular interactions has been reported in mammals only during a "critical" period in juvenile life, wherein monocular deprivation (MD) causes an enduring loss of visual acuity (amblyopia) selectively through the deprived eye. Here, we report a different form of interocular plasticity of vision in adult mice in which MD leads to an enhancement of the optokinetic response (OKR) selectively through the nondeprived eye. Over 5 d of MD, the spatial frequency sensitivity of the OKR increased gradually, reaching a plateau of approximately 36% above pre-deprivation baseline. Eye opening initiated a gradual decline, but sensitivity was maintained above pre-deprivation baseline for 5-6 d. Enhanced function was restricted to the monocular visual field, notwithstanding the dependence of the plasticity on binocular interactions. Activity in visual cortex ipsilateral to the deprived eye was necessary for the characteristic induction of the enhancement, and activity in visual cortex contralateral to the deprived eye was necessary for its maintenance after MD. The plasticity also displayed distinct learning-like properties: Active testing experience was required to attain maximal enhancement and for enhancement to persist after MD, and the duration of enhanced sensitivity after MD was extended by increasing the length of MD, and by repeating MD. These data show that the adult mouse visual system maintains a form of experience-dependent plasticity in which the visual cortex can modulate the normal function of subcortical visual pathways.

Mirror Observation of Finger Action Enhances Activity in Anterior Intraparietal Sulcus: A Functional Magnetic Resonance Imaging Study

PubMed Central

Murayama, Takashi; Takasugi, Jun; Monma, Masahiko; Oga, Masaru

2013-01-01

Mirror therapy can be used to promote recovery from paralysis in patients with post-stroke hemiplegia, There are a lot of reports that mirror-image observation of the unilateral moving hand enhanced the excitability of the primary motor area (M1) ipsilateral to the moving hand in healthy subjects. but the neural mechanisms underlying its therapeutic effects are currently unclear. To investigate this issue, we used functional magnetic resonance imaging to measure activity in brain regions related to visual information processing during mirror image movement observation. Thirteen healthy subjects performed a finger-thumb opposition task with the left and right hands separately, with or without access to mirror observation. In the mirror condition, one hand was reflected in a mirror placed above the abdomen in the MRI scanner. In the masked mirror condition, subjects performed the same task but with the mirror obscured. In both conditions, the other hand was held at rest behind the mirror. A between-task comparison (mirror versus masked mirror) revealed significant activation in the ipsilateral hemisphere in the anterior intraparietal sulcus (aIP) while performing all tasks, regardless of which hand was used. The right aIP was significantly activated while moving the right hand. In contrast, in the left aIP, a small number of voxels showed a tendency toward activation during both left and right hand movement. The enhancement of ipsilateral aIP activity by the mirror image observation of finger action suggests that bimodal aIP neurons can be activated by visual information. We propose that activation in the M1 ipsilateral to the moving hand can be induced by information passing through the ventral premotor area from the aIP. PMID:25792898

The second visual area in the marmoset monkey: visuotopic organisation, magnification factors, architectonical boundaries, and modularity.

PubMed

Rosa, M G; Fritsches, K A; Elston, G N

1997-11-03

The organisation of the second visual area (V2) in marmoset monkeys was studied by means of extracellular recordings of responses to visual stimulation and examination of myelin- and cytochrome oxidase-stained sections. Area V2 forms a continuous cortical belt of variable width (1-2 mm adjacent to the foveal representation of V1, and 3-3.5 mm near the midline and on the tentorial surface) bordering V1 on the lateral, dorsal, medial, and tentorial surfaces of the occipital lobe. The total surface area of V2 is approximately 100 mm2, or about 50% of the surface area of V1 in the same individuals. In each hemisphere, the receptive fields of V2 neurones cover the entire contralateral visual hemifield, forming an ordered visuotopic representation. As in other simians, the dorsal and ventral halves of V2 represent the lower and upper contralateral quadrants, respectively, with little invasion of the ipsilateral hemifield. The representation of the vertical meridian forms the caudal border of V2, with V1, whereas a field discontinuity approximately coincident with the horizontal meridian forms the rostral border of V2, with other visually responsive areas. The bridge of cortex connecting dorsal and ventral V2 contains neurones with receptive fields centred within 1 degree of the centre of the fovea. The visuotopy, size, shape and location of V2 show little variation among individuals. Analysis of cortical magnification factor (CMF) revealed that the V2 map of the visual field is highly anisotropic: for any given eccentricity, the CMF is approximately twice as large in the dimension parallel to the V1/V2 border as it is perpendicular to this border. Moreover, comparison of V2 and V1 in the same individuals demonstrated that the representation of the central visual field is emphasised in V2, relative to V1. Approximately half of the surface area of V2 is dedicated to the representation of the central 5 degrees of the visual field. Calculations based on the CMF, receptive field scatter, and receptive field size revealed that the point-image size measured parallel to the V1/V2 border (2-3 mm) equals the width of a full cycle of cytochrome oxidase stripes in V2, suggesting a close correspondence between physiological and anatomical estimates of the dimensions of modular components in this area.

Reliability of Visual and Somatosensory Feedback in Skilled Movement: The Role of the Cerebellum.

PubMed

Mizelle, J C; Oparah, Alexis; Wheaton, Lewis A

2016-01-01

The integration of vision and somatosensation is required to allow for accurate motor behavior. While both sensory systems contribute to an understanding of the state of the body through continuous updating and estimation, how the brain processes unreliable sensory information remains to be fully understood in the context of complex action. Using functional brain imaging, we sought to understand the role of the cerebellum in weighting visual and somatosensory feedback by selectively reducing the reliability of each sense individually during a tool use task. We broadly hypothesized upregulated activation of the sensorimotor and cerebellar areas during movement with reduced visual reliability, and upregulated activation of occipital brain areas during movement with reduced somatosensory reliability. As specifically compared to reduced somatosensory reliability, we expected greater activations of ipsilateral sensorimotor cerebellum for intact visual and somatosensory reliability. Further, we expected that ipsilateral posterior cognitive cerebellum would be affected with reduced visual reliability. We observed that reduced visual reliability results in a trend towards the relative consolidation of sensorimotor activation and an expansion of cerebellar activation. In contrast, reduced somatosensory reliability was characterized by the absence of cerebellar activations and a trend towards the increase of right frontal, left parietofrontal activation, and temporo-occipital areas. Our findings highlight the role of the cerebellum for specific aspects of skillful motor performance. This has relevance to understanding basic aspects of brain functions underlying sensorimotor integration, and provides a greater understanding of cerebellar function in tool use motor control.

Spatial updating in human parietal cortex

NASA Technical Reports Server (NTRS)

Merriam, Elisha P.; Genovese, Christopher R.; Colby, Carol L.

2003-01-01

Single neurons in monkey parietal cortex update visual information in conjunction with eye movements. This remapping of stimulus representations is thought to contribute to spatial constancy. We hypothesized that a similar process occurs in human parietal cortex and that we could visualize it with functional MRI. We scanned subjects during a task that involved remapping of visual signals across hemifields. We observed an initial response in the hemisphere contralateral to the visual stimulus, followed by a remapped response in the hemisphere ipsilateral to the stimulus. We ruled out the possibility that this remapped response resulted from either eye movements or visual stimuli alone. Our results demonstrate that updating of visual information occurs in human parietal cortex.

Callosal Influence on Visual Receptive Fields Has an Ocular, an Orientation-and Direction Bias.

PubMed

Conde-Ocazionez, Sergio A; Jungen, Christiane; Wunderle, Thomas; Eriksson, David; Neuenschwander, Sergio; Schmidt, Kerstin E

2018-01-01

One leading hypothesis on the nature of visual callosal connections (CC) is that they replicate features of intrahemispheric lateral connections. However, CC act also in the central part of the binocular visual field. In agreement, early experiments in cats indicated that they provide the ipsilateral eye part of binocular receptive fields (RFs) at the vertical midline (Berlucchi and Rizzolatti, 1968), and play a key role in stereoscopic function. But until today callosal inputs to receptive fields activated by one or both eyes were never compared simultaneously, because callosal function has been often studied by cutting or lesioning either corpus callosum or optic chiasm not allowing such a comparison. To investigate the functional contribution of CC in the intact cat visual system we recorded both monocular and binocular neuronal spiking responses and receptive fields in the 17/18 transition zone during reversible deactivation of the contralateral hemisphere. Unexpectedly from many of the previous reports, we observe no change in ocular dominance during CC deactivation. Throughout the transition zone, a majority of RFs shrink, but several also increase in size. RFs are significantly more affected for ipsi- as opposed to contralateral stimulation, but changes are also observed with binocular stimulation. Noteworthy, RF shrinkages are tiny and not correlated to the profound decreases of monocular and binocular firing rates. They depend more on orientation and direction preference than on eccentricity or ocular dominance of the receiving neuron's RF. Our findings confirm that in binocularly viewing mammals, binocular RFs near the midline are constructed via the direct geniculo-cortical pathway. They also support the idea that input from the two eyes complement each other through CC: Rather than linking parts of RFs separated by the vertical meridian, CC convey a modulatory influence, reflecting the feature selectivity of lateral circuits, with a strong cardinal bias.

Dosimetric comparison of normal structures associated with accelerated partial breast irradiation and whole breast irradiation delivered by intensity modulated radiotherapy for early breast cancer after breast conserving surgery.

PubMed

Wu, S; He, Z; Guo, J; Li, F; Lin, Q; Guan, X

2014-01-01

To assess the heart and lung dosimetry results associated with accelerated partial breast irradiation intensity-modulated radiotherapy (APBI-IMRT) and whole breast field-in-field intensity-modulated radiotherapy (WBI-FIF-IMRT). A total of 29 patients with early-stage breast cancer after lumpectomy were included in this study. APBI-IMRT and WBI-FIF-IMRT plans were generated for each patient. The dosimetric parameters of ipsilateral lung and heart in both plans were then compared with and without radiobiological correction. With and without radiobiological correction, the volume of ipsilateral lung showed a substantially lower radiation exposure in APBI-IMRT with moderate to high doses (P < 0.05) but non-significant increases in volume of ipsilateral lung in 2.5 Gy than WBI-FIF-IMRT (P > 0.905).There was no significant difference in volume of ipsilateral lung receiving 1, 2.5, and 5 Gy between APBI-IMRT and WBI (P > 0.05) in patients with medial tumor location, although APBI-IMRT exposed more lung to 2.5 and 5 Gy. APBI-IMRT significantly decreases the volume of heart receiving low to high doses in left-sided breast cancer (P < 0.05). APBI-IMRT can significantly spare the volume of heart and ipsilateral lung receiving moderate and high dose. Non-significant increases in volume of the ipsilateral lung exposed to low doses of radiation were observed for APBI-IMRT in comparison to WBI-FIF-IMRT, particularly in patients with medial tumor location. With the increasing interest in APBI-IMRT, our data may help clinicians individualize patient treatment decisions.

Lateralization of the human mirror neuron system.

PubMed

Aziz-Zadeh, Lisa; Koski, Lisa; Zaidel, Eran; Mazziotta, John; Iacoboni, Marco

2006-03-15

A cortical network consisting of the inferior frontal, rostral inferior parietal, and posterior superior temporal cortices has been implicated in representing actions in the primate brain and is critical to imitation in humans. This neural circuitry may be an evolutionary precursor of neural systems associated with language. However, language is predominantly lateralized to the left hemisphere, whereas the degree of lateralization of the imitation circuitry in humans is unclear. We conducted a functional magnetic resonance imaging study of imitation of finger movements with lateralized stimuli and responses. During imitation, activity in the inferior frontal and rostral inferior parietal cortex, although fairly bilateral, was stronger in the hemisphere ipsilateral to the visual stimulus and response hand. This ipsilateral pattern is at variance with the typical contralateral activity of primary visual and motor areas. Reliably increased signal in the right superior temporal sulcus (STS) was observed for both left-sided and right-sided imitation tasks, although subthreshold activity was also observed in the left STS. Overall, the data indicate that visual and motor components of the human mirror system are not left-lateralized. The left hemisphere superiority for language, then, must be have been favored by other types of language precursors, perhaps auditory or multimodal action representations.

Kinesthetic but not visual imagery assists in normalizing the CNV in Parkinson's disease.

PubMed

Lim, Vanessa K; Polych, Melody A; Holländer, Antje; Byblow, Winston D; Kirk, Ian J; Hamm, Jeff P

2006-10-01

This study investigated whether kinesthetic and/or visual imagery could alter the contingent negative variation (CNV) for patients with Parkinson's disease (PD). The CNV was recorded in six patients with PD and seven controls before and after a 10min block of imagery. There were two types of imagery employed: kinesthetic and visual, which were evaluated on separate days. The global field power (GFP) of the late CNV did not change after the visual imagery for either group, nor was there a significant difference between the groups. In contrast, kinesthetic imagery resulted in significant group differences pre-, versus post-imagery GFPs, which was not present prior to performing the kinesthetic imagery task. In patients with PD, the CNV amplitudes post-, relative to pre-kinesthetic imagery, increased over the dorsolateral prefrontal regions and decreased in the ipsilateral parietal regions. There were no such changes in controls. A 10-min session of kinesthetic imagery enhanced the GFP amplitude of the late CNV for patients but not for controls. While the study needs to be replicated with a greater number of participants, the results suggest that kinesthetic imagery may be a promising tool for investigations into motor changes, and may potentially be employed therapeutically, in patients with Parkinson's disease.

Step-related discharges of Purkinje cells in the paravermal cortex of the cerebellar anterior lobe in the cat.

PubMed Central

Edgley, S A; Lidierth, M

1988-01-01

1. Extracellular recordings were made of the simple spike discharges of Purkinje cells in the lateral part of the paravermal cortex of lobule V in the cerebellum of awake cats. The cells were located within the c2 and c3 zones of Oscarsson (1979). 2. The peripheral receptive fields in which light mechanical stimuli could evoke simple spikes were examined in 252 Purkinje cells. Ninety-two per cent were activated by stimulation of the ipsilateral forelimb and 52% of 113 tested cells also discharged simple spikes in response to stimulation of the contralateral forelimb. The receptive fields were concentrated on the distal parts of the limbs: 67% of the 139 cells which were examined in most detail responded to stimulation of the paw or wrist of the ipsilateral forelimb. 3. In 135 of the Purkinje cells, the discharges were recorded during locomotion. Simple spikes were discharged at a mean rate of 54.3 +/- 27.8 impulses/s (S.D., n = 135) during steady walking on a belt moving at 0.5-0.7 m/s. The discharges of each cell were rhythmically modulated in time with the movements of stepping and although the timings of the discharges were highly variable between cells, activity in the population was greatest at the times of transition between the stance and swing phases in the ipsilateral forelimb and least during mid-stance. 4. As a population Purkinje cells with simple spike receptive fields on the distal parts of the forelimb(s) exhibited two activity maxima. These occurred during early stance and during the transition from stance to swing in the ipsilateral forelimb. Cells with receptive fields on the proximal parts of the limb achieved an activity maximum during late swing, and their average discharge rate fell at the time of onset of the swing phase in the ipsilateral forelimb instead of rising as was the case for the distal group. 5. The present results are compared with those from cells located more medially in the paravermal cortex. It is shown that medially located cells tend to discharge earlier in stance (or in late flexion) than laterally located cells with similar receptive fields. PMID:3171993

The compensatory dynamic of inter-hemispheric interactions in visuospatial attention revealed using rTMS and fMRI.

PubMed

Plow, Ela B; Cattaneo, Zaira; Carlson, Thomas A; Alvarez, George A; Pascual-Leone, Alvaro; Battelli, Lorella

2014-01-01

A balance of mutual tonic inhibition between bi-hemispheric posterior parietal cortices is believed to play an important role in bilateral visual attention. However, experimental support for this notion has been mainly drawn from clinical models of unilateral damage. We have previously shown that low-frequency repetitive TMS (rTMS) over the intraparietal sulcus (IPS) generates a contralateral attentional deficit in bilateral visual tracking. Here, we used functional magnetic resonance imaging (fMRI) to study whether rTMS temporarily disrupts the inter-hemispheric balance between bilateral IPS in visual attention. Following application of 1 Hz rTMS over the left IPS, subjects performed a bilateral visual tracking task while their brain activity was recorded using fMRI. Behaviorally, tracking accuracy was reduced immediately following rTMS. Areas ventro-lateral to left IPS, including inferior parietal lobule (IPL), lateral IPS (LIPS), and middle occipital gyrus (MoG), showed decreased activity following rTMS, while dorsomedial areas, such as Superior Parietal Lobule (SPL), Superior occipital gyrus (SoG), and lingual gyrus, as well as middle temporal areas (MT+), showed higher activity. The brain activity of the homologues of these regions in the un-stimulated, right hemisphere was reversed. Interestingly, the evolution of network-wide activation related to attentional behavior following rTMS showed that activation of most occipital synergists adaptively compensated for contralateral and ipsilateral decrement after rTMS, while activation of parietal synergists, and SoG remained competing. This pattern of ipsilateral and contralateral activations empirically supports the hypothesized loss of inter-hemispheric balance that underlies clinical manifestation of visual attentional extinction.

Neural connectivity of the lateral geniculate body in the human brain: diffusion tensor imaging study.

PubMed

Kwon, Hyeok Gyu; Jang, Sung Ho

2014-08-22

A few studies have reported on the neural connectivity of some neural structures of the visual system in the human brain. However, little is known about the neural connectivity of the lateral geniculate body (LGB). In the current study, using diffusion tensor tractography (DTT), we attempted to investigate the neural connectivity of the LGB in normal subjects. A total of 52 healthy subjects were recruited for this study. A seed region of interest was placed on the LGB using the FMRIB Software Library which is a probabilistic tractography method based on a multi-fiber model. Connectivity was defined as the incidence of connection between the LGB and target brain areas at the threshold of 5, 25, and 50 streamlines. In addition, connectivity represented the percentage of connection in all hemispheres of 52 subjects. We found the following characteristics of connectivity of the LGB at the threshold of 5 streamline: (1) high connectivity to the corpus callosum (91.3%) and the contralateral temporal cortex (56.7%) via the corpus callosum, (2) high connectivity to the ipsilateral cerebral cortex: the temporal lobe (100%), primary visual cortex (95.2%), and visual association cortex (77.9%). The LGB appeared to have high connectivity to the corpus callosum and both temporal cortexes as well as the ipsilateral occipital cortex. We believe that the results of this study would be helpful in investigation of the neural network associated with the visual system and brain plasticity of the visual system after brain injury. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Improved method for retinotopy constrained source estimation of visual evoked responses

PubMed Central

Hagler, Donald J.; Dale, Anders M.

2011-01-01

Retinotopy constrained source estimation (RCSE) is a method for non-invasively measuring the time courses of activation in early visual areas using magnetoencephalography (MEG) or electroencephalography (EEG). Unlike conventional equivalent current dipole or distributed source models, the use of multiple, retinotopically-mapped stimulus locations to simultaneously constrain the solutions allows for the estimation of independent waveforms for visual areas V1, V2, and V3, despite their close proximity to each other. We describe modifications that improve the reliability and efficiency of this method. First, we find that increasing the number and size of visual stimuli results in source estimates that are less susceptible to noise. Second, to create a more accurate forward solution, we have explicitly modeled the cortical point spread of individual visual stimuli. Dipoles are represented as extended patches on the cortical surface, which take into account the estimated receptive field size at each location in V1, V2, and V3 as well as the contributions from contralateral, ipsilateral, dorsal, and ventral portions of the visual areas. Third, we implemented a map fitting procedure to deform a template to match individual subject retinotopic maps derived from functional magnetic resonance imaging (fMRI). This improves the efficiency of the overall method by allowing automated dipole selection, and it makes the results less sensitive to physiological noise in fMRI retinotopy data. Finally, the iteratively reweighted least squares (IRLS) method was used to reduce the contribution from stimulus locations with high residual error for robust estimation of visual evoked responses. PMID:22102418

Educating the blind brain: a panorama of neural bases of vision and of training programs in organic neurovisual deficits

PubMed Central

Coubard, Olivier A.; Urbanski, Marika; Bourlon, Clémence; Gaumet, Marie

2014-01-01

Vision is a complex function, which is achieved by movements of the eyes to properly foveate targets at any location in 3D space and to continuously refresh neural information in the different visual pathways. The visual system involves five main routes originating in the retinas but varying in their destination within the brain: the occipital cortex, but also the superior colliculus (SC), the pretectum, the supra-chiasmatic nucleus, the nucleus of the optic tract and terminal dorsal, medial and lateral nuclei. Visual pathway architecture obeys systematization in sagittal and transversal planes so that visual information from left/right and upper/lower hemi-retinas, corresponding respectively to right/left and lower/upper visual fields, is processed ipsilaterally and ipsialtitudinally to hemi-retinas in left/right hemispheres and upper/lower fibers. Organic neurovisual deficits may occur at any level of this circuitry from the optic nerve to subcortical and cortical destinations, resulting in low or high-level visual deficits. In this didactic review article, we provide a panorama of the neural bases of eye movements and visual systems, and of related neurovisual deficits. Additionally, we briefly review the different schools of rehabilitation of organic neurovisual deficits, and show that whatever the emphasis is put on action or perception, benefits may be observed at both motor and perceptual levels. Given the extent of its neural bases in the brain, vision in its motor and perceptual aspects is also a useful tool to assess and modulate central nervous system (CNS) in general. PMID:25538575

Quantifying interictal metabolic activity in human temporal lobe epilepsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, T.R.; Mazziotta, J.C.; Engel, J. Jr.

1990-09-01

The majority of patients with complex partial seizures of unilateral temporal lobe origin have interictal temporal hypometabolism on (18F)fluorodeoxyglucose positron emission tomography (FDG PET) studies. Often, this hypometabolism extends to ipsilateral extratemporal sites. The use of accurately quantified metabolic data has been limited by the absence of an equally reliable method of anatomical analysis of PET images. We developed a standardized method for visual placement of anatomically configured regions of interest on FDG PET studies, which is particularly adapted to the widespread, asymmetric, and often severe interictal metabolic alterations of temporal lobe epilepsy. This method was applied by a singlemore » investigator, who was blind to the identity of subjects, to 10 normal control and 25 interictal temporal lobe epilepsy studies. All subjects had normal brain anatomical volumes on structural neuroimaging studies. The results demonstrate ipsilateral thalamic and temporal lobe involvement in the interictal hypometabolism of unilateral temporal lobe epilepsy. Ipsilateral frontal, parietal, and basal ganglial metabolism is also reduced, although not as markedly as is temporal and thalamic metabolism.« less

Myofascial involvement of supra- and infraspinatus muscles contributes to ipsilateral shoulder pain after muscle-sparing thoracotomy and video-assisted thoracic surgery.

PubMed

Ohmori, Aki; Iranami, Hiroshi; Fujii, Keisuke; Yamazaki, Akinori; Doko, Yukari

2013-12-01

This study examined the hypothesis that ipsilateral upper extremity elevation for muscle-sparing thoracotomy procedures contributes to the postoperative shoulder pain. Prospective observational study. Medical center. ASA physical status 1-2 patients undergoing elective lung surgeries including pneumonectomy, lobectomy, and segmentectomy performed through either the anterolateral approach or video-assisted thoracotomy surgery. Postoperative observation of ipsilateral shoulder pain. Postoperative examinations of sites of shoulder pain (clavicle, anterior, lateral,or posterior aspect of acromion, posterior neck, supraspinatus, infraspinatus, and these entire areas) with or without trigger points, visual analog scale score of wound pain, and requested counts of analgesics. The number of patients who suffered from postoperative shoulder pain was 37 of 70 (52.9%). Demographic data, anterolateral/VATS ratio, VAS scores, and requested counts of rescue analgesics requirement were similar in the groups of patients with and without postoperative shoulder pain. The segmentectomy caused a significantly higher incidence of postoperative shoulder pain compared with other procedures (p < 0.05). The supra- and infraspinatus were significantly higher areas of painful regions compared to the other sites. The 16 of 37 patients (43.2%) with shoulder pain showed defined trigger points in their painful areas. These results supported the hypothesis that myofascial involvement contributed, to some extent, to shoulder pain after muscle-sparing thoracotomy with ipsilateral upper extremity elevation. Copyright © 2013 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, H; Cape Breton Cancer Centre, Sydney, NS

Purpose: To perform the comparison of dose distributions and dosevolume- histograms generated by VMAT and conventional field-in-field technique for left-sided breast and chestwall cancers; to determine whether VMAT offers more dosimetric benefits than does the field-in-field technique. Methods: All VMAT and field-in-filed plans were produced in Eclipse(version 10). Five plans were generated for left-sided breast and leftsided chestwall with supraclavicular nodes, respectively. A clockwise arc (CW) and a counter-clockwise arc (CCW) were used with start and stop angles being 310o±10o and 140o±10o. Collimator angles were 30o for CW and 330o for CCW. The conformity index (CI) is the ratio ofmore » V95% over PTV. The homogeneity index (HI) is the ratio of the difference between D2% and D98% over the prescribed dose. The V5, as an indicator of low dose bath to organs-at-risk, was used for ipsilateral lung, heart, contralateral lung, and contralateral breast. The V20, as an indicator of radiation pneumonitis, was used for ipsilateral lung. Results: Breast/chestwall VMAT delivers much higher low dose bath to ipsilateral lung, contralateral lung and contralateral breast/chestwall for both intact breast and chestwall with nodes. V5 for heart is increased in VMAT plans. V20 for ipsilateral lung is lower in VMAT plans. PTV coverage is similar for both techniques. For one particular chestwall patient with supraclavicular and internal mammary nodes, VMAT offers superior dose coverage of PTVs with slightly more low-dose-wash to heart, contralateral lung and contralateral breast. Conclusion: This study indicates that there is generally no benefit using VMAT for left-sided intact breast, due to large low-dose-bath (5Gy) to normal tissues with insignificant improvement in PTV coverage. Dosimetric benefits will be seen in VMAT plans for some chestwall patients with large size, and/or internal mammary nodes, etc. Whether a chestwall patient is treated with VMAT should be carefully analyzed on an individual basis.« less

GABA-mediated changes in inter-hemispheric beta frequency activity in early-stage Parkinson’s disease

PubMed Central

Hall, S.D.; Prokic, E.J.; McAllister, C.J.; Ronnqvist, K.C.; Williams, A.C.; Yamawaki, N.; Witton, C.; Woodhall, G.L.; Stanford, I.M.

2014-01-01

In Parkinson’s disease (PD), elevated beta (15–35 Hz) power in subcortical motor networks is widely believed to promote aspects of PD symptomatology, moreover, a reduction in beta power and coherence accompanies symptomatic improvement following effective treatment with l-DOPA. Previous studies have reported symptomatic improvements that correlate with changes in cortical network activity following GABAA receptor modulation. In this study we have used whole-head magnetoencephalography to characterize neuronal network activity, at rest and during visually cued finger abductions, in unilaterally symptomatic PD and age-matched control participants. Recordings were then repeated following administration of sub-sedative doses of the hypnotic drug zolpidem (0.05 mg/kg), which binds to the benzodiazepine site of the GABAA receptor. A beamforming based ‘virtual electrode’ approach was used to reconstruct oscillatory power in the primary motor cortex (M1), contralateral and ipsilateral to symptom presentation in PD patients or dominant hand in control participants. In PD patients, contralateral M1 showed significantly greater beta power than ipsilateral M1. Following zolpidem administration contralateral beta power was significantly reduced while ipsilateral beta power was significantly increased resulting in a hemispheric power ratio that approached parity. Furthermore, there was highly significant correlation between hemispheric beta power ratio and Unified Parkinson’s Disease Rating Scale (UPDRS). The changes in contralateral and ipsilateral beta power were reflected in pre-movement beta desynchronization and the late post-movement beta rebound. However, the absolute level of movement-related beta desynchronization was not altered. These results show that low-dose zolpidem not only reduces contralateral beta but also increases ipsilateral beta, while rebalancing the dynamic range of M1 network oscillations between the two hemispheres. These changes appear to underlie the symptomatic improvements afforded by low-dose zolpidem. PMID:25261686

The amygdala and basal forebrain as a pathway for motivationally guided attention.

PubMed

Peck, Christopher J; Salzman, C Daniel

2014-10-08

Visual stimuli associated with rewards attract spatial attention. Neurophysiological mechanisms that mediate this process must register both the motivational significance and location of visual stimuli. Recent neurophysiological evidence indicates that the amygdala encodes information about both of these parameters. Furthermore, the firing rate of amygdala neurons predicts the allocation of spatial attention. One neural pathway through which the amygdala might influence attention involves the intimate and bidirectional connections between the amygdala and basal forebrain (BF), a brain area long implicated in attention. Neurons in the rhesus monkey amygdala and BF were therefore recorded simultaneously while subjects performed a detection task in which the stimulus-reward associations of visual stimuli modulated spatial attention. Neurons in BF were spatially selective for reward-predictive stimuli, much like the amygdala. The onset of reward-predictive signals in each brain area suggested different routes of processing for reward-predictive stimuli appearing in the ipsilateral and contralateral fields. Moreover, neurons in the amygdala, but not BF, tracked trial-to-trial fluctuations in spatial attention. These results suggest that the amygdala and BF could play distinct yet inter-related roles in influencing attention elicited by reward-predictive stimuli. Copyright © 2014 the authors 0270-6474/14/3413757-11$15.00/0.

The compensatory dynamic of inter-hemispheric interactions in visuospatial attention revealed using rTMS and fMRI

PubMed Central

Plow, Ela B.; Cattaneo, Zaira; Carlson, Thomas A.; Alvarez, George A.; Pascual-Leone, Alvaro; Battelli, Lorella

2014-01-01

A balance of mutual tonic inhibition between bi-hemispheric posterior parietal cortices is believed to play an important role in bilateral visual attention. However, experimental support for this notion has been mainly drawn from clinical models of unilateral damage. We have previously shown that low-frequency repetitive TMS (rTMS) over the intraparietal sulcus (IPS) generates a contralateral attentional deficit in bilateral visual tracking. Here, we used functional magnetic resonance imaging (fMRI) to study whether rTMS temporarily disrupts the inter-hemispheric balance between bilateral IPS in visual attention. Following application of 1 Hz rTMS over the left IPS, subjects performed a bilateral visual tracking task while their brain activity was recorded using fMRI. Behaviorally, tracking accuracy was reduced immediately following rTMS. Areas ventro-lateral to left IPS, including inferior parietal lobule (IPL), lateral IPS (LIPS), and middle occipital gyrus (MoG), showed decreased activity following rTMS, while dorsomedial areas, such as Superior Parietal Lobule (SPL), Superior occipital gyrus (SoG), and lingual gyrus, as well as middle temporal areas (MT+), showed higher activity. The brain activity of the homologues of these regions in the un-stimulated, right hemisphere was reversed. Interestingly, the evolution of network-wide activation related to attentional behavior following rTMS showed that activation of most occipital synergists adaptively compensated for contralateral and ipsilateral decrement after rTMS, while activation of parietal synergists, and SoG remained competing. This pattern of ipsilateral and contralateral activations empirically supports the hypothesized loss of inter-hemispheric balance that underlies clinical manifestation of visual attentional extinction. PMID:24860462

Effect of visual feedback on brain activation during motor tasks: an FMRI study.

PubMed

Noble, Jeremy W; Eng, Janice J; Boyd, Lara A

2013-07-01

This study examined the effect of visual feedback and force level on the neural mechanisms responsible for the performance of a motor task. We used a voxel-wise fMRI approach to determine the effect of visual feedback (with and without) during a grip force task at 35% and 70% of maximum voluntary contraction. Two areas (contralateral rostral premotor cortex and putamen) displayed an interaction between force and feedback conditions. When the main effect of feedback condition was analyzed, higher activation when visual feedback was available was found in 22 of the 24 active brain areas, while the two other regions (contralateral lingual gyrus and ipsilateral precuneus) showed greater levels of activity when no visual feedback was available. The results suggest that there is a potentially confounding influence of visual feedback on brain activation during a motor task, and for some regions, this is dependent on the level of force applied.

Antennal pointing at a looming object in the cricket Acheta domesticus.

PubMed

Yamawaki, Yoshifumi; Ishibashi, Wakako

2014-01-01

Antennal pointing responses to approaching objects were observed in the house cricket Acheta domesticus. In response to a ball approaching from the lateral side, crickets oriented the antenna ipsilateral to the ball towards it. In response to a ball approaching from the front, crickets oriented both antennae forward. Response rates of antennal pointing were higher when the ball was approaching from the front than from behind. The antennal angle ipsilateral to the approaching ball was positively correlated with approaching angle of the ball. Obstructing the cricket's sight decreased the response rate of antennal pointing, suggesting that this response was elicited mainly by visual stimuli. Although the response rates of antennal pointing decreased when the object ceased its approach at a great distance from the cricket, antennal pointing appeared to be resistant to habituation and was not substantially affected by the velocity, size and trajectory of an approaching ball. When presented with computer-generated visual stimuli, crickets frequently showed the antennal pointing response to a darkening stimulus as well as looming and linearly-expanding stimuli. Drifting gratings rarely elicited the antennal pointing. These results suggest that luminance change is sufficient to elicit antennal pointing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Axillary lymph node uptake of technetium-99m-MDP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ongseng, F.; Goldfarb, C.R.; Finestone, H.

We sought to determine the frequency and significance of axillary lymph node visualization on bone scans performed with diphosphonates. Consecutive {sup 99m}Tc-methylene diphosphonate ({sup 99m}Tc-MDP) bone scans (2435) were inspected for axillary soft-tissue uptake. In positive cases, the results of physical examination, correlative imaging studies and serial bone scans were recorded, as was the site of venipuncture. Forty-eight studies (2%) showed axillary uptake ipsilateral to the injection site. Extravasation of tracer, documented by focal activity near the injection site, was present in every case. There was no association with axillary adenopathy, mass, induration of radiographically visible calcification. On some images,more » foci adjacent to the axilla were superimposed on the rib, scapula, or humerus. The bone-to-background ratio was frequently reduced; repeat imaging after 1-2 hr usually improved osseous detail. Ipsilateral axillary lymph node visualization due to extravasation of {sup 99m}Tc-MDP is frequently associated with additional foci superimposed on osseous structures simulating pathology. Delayed skeletal uptake is common in such cases and necessitates a greater time interval between injection and imaging. 7 refs., 3 figs.« less

Clinical Features of Ocular Ischemic Syndrome and Risk Factors for Neovascular Glaucoma.

PubMed

Kim, Yung Hui; Sung, Mi Sun; Park, Sang Woo

2017-08-01

We aimed to examine the clinical features and prognosis of ocular ischemic syndrome and to investigate the risk factors for the development of neovascular glaucoma (NVG). The medical records from 25 patients (25 eyes) who were diagnosed with ocular ischemic syndrome were retrospectively analyzed. We recorded the length of time between symptom onset and diagnosis, visual acuity, intraocular pressure, clinical findings of the anterior and posterior segments of the eye, fluorescein angiography, systemic diseases, smoking history, and the extent of any ipsilateral carotid artery stenosis. The risk factors for NVG in patients with ocular ischemic syndrome were investigated. The mean age was 67.9 ± 12.5 years, and 21 men and 4 women were included in this study. At initial examination, the mean logarithm of the minimum angle of resolution (logMAR) was 2.02 ± 1.26, and the mean intraocular pressure was 21.0 ± 10.3 mmHg. Among 25 eyes of the 25 patients, NVG occurred in 17 eyes after a mean period of 12.6 ± 14.0 months. The length of time between symptom onset and diagnosis (p = 0.025) and the extent of ipsilateral carotid artery stenosis (p = 0.032) were identified as significant risk factors for NVG. At the final follow-up, the mean logMAR visual acuity was 3.13 ± 1.24, showing a poor prognosis regardless of whether NVG occurred. Overall, the prognosis for ocular ischemic syndrome is very poor. The risk of NVG increases with the length of time between symptom onset and diagnosis, as well as with the severity of ipsilateral carotid artery stenosis. © 2017 The Korean Ophthalmological Society

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, H; Malin, M; Chmura, S

Purpose: For African-American patients receiving breast radiotherapy with a bolus, skin darkening can affect the surface visualization when using optical imaging for daily positioning and gating at deep-inspiration breath holds (DIBH). Our goal is to identify a region-of-interest (ROI) that is robust against deteriorating surface image quality due to skin darkening. Methods: We study four patients whose post-mastectomy surfaces are imaged daily with AlignRT (VisionRT, UK) for DIBH radiotherapy and whose surface image quality is degraded toward the end of treatment. To simulate the effects of skin darkening, surfaces from the first ten fractions of each patient are systematically degradedmore » by 25–35%, 40–50% and 65–75% of the total area of the clinically used ROI-ipsilateral-chestwall. The degraded surfaces are registered to the reference surface in six degrees-of-freedom. To identify a robust ROI, three additional reference ROIs — ROI-chest+abdomen, ROI-bilateral-chest and ROI-extended-ipsilateral-chestwall are created and registered to the degraded surfaces. Differences in registration using these ROIs are compared to that using ROI-ipsilateral-chestwall. Results: For three patients, the deviations in the registrations to ROI-ipsilateral-chestwall are > 2.0, 3.1 and 7.9mm on average for 25–35%, 40–50% and 65–75% degraded surfaces, respectively. Rotational deviations reach 11.1° in pitch. For the last patient, registration is consistent to within 2.6mm even on the 65–75% degraded surfaces, possibly because the surface topography has more distinct features. For ROI-bilateral-chest and ROI-extended-ipsilateral-chest registrations deviate in a similar pattern. However, registration on ROI-chest+abdomen is robust to deteriorating image qualities to within 4.2mm for all four patients. Conclusion: Registration deviations using ROI-ipsilateral-chestwall can reach 9.8mm on the 40–50% degraded surfaces. Caution is required when using AlignRT for patients experiencing skin darkening since the accuracy of AlignRT registration deteriorates. To avoid this inaccuracy, we recommend use of ROI-chest+abdomen, on which registration is consistent within 4.2mm even for highly degraded surfaces.« less

Brain stem origins of spinal projections in the lizard Tupinambis nigropunctatus.

PubMed

Cruce, W L; Newman, D B

1981-05-10

In order to study brainstem origins of spinal projections, ten Tegu lizards (Tupinambis nigropunctatus) received complete or partial hemisections of the spinal cord at the first or second cervical segment. Their brains were processed for conventional Nissl staining. The sections were surveyed for the presence or absence of retrograde chromatolysis. Based on analysis and comparison of results from lesions in the various spinal cord funiculi, the following conclusions were reached: The interstitial nucleus projects ipsilaterally to the spinal cord via the medial longitudinal fasciculus, as does the middle reticular field of the metencephalon. The red nucleus and dorsal vagal motor nucleus both project contralaterally to the spinal cord via the dorsal part of the lateral funiculus. The superior reticular field in the rostral metencephalon and the ventrolateral vestibular nucleus project ipsilaterally to the spinal cord via the ventral funiculus. The dorsolateral metencephalic nucleus and the ventral part of the inferior reticular nucleus of the myelencephalon both project ipsilaterally to the spinal cord via the dorsal part of the lateral funiculus. Several brainstem nuclei in Tupinambis project bilaterally to the spinal cord. The ventrolateral metencephalic nucleus, for example, projects ipsilaterally to the cord via the medial longitudinal fasciculus and contralaterally via the dorsal part of the lateral funiculus. The dorsal part of the inferior reticular nucleus projects bilaterally to the spinal cord via the dorsal part of the lateral funiculus. The nucleus solitarius complex projects contralaterally via the dorsal part of the lateral funiculus but ipsilaterally via the middle of the lateral funiculus. The inferior raphe nucleus projects bilaterally to the spinal cord via the middle part of the lateral funiculus. These data suggest that supraspinal projections in reptiles, especially reticulospinal systems, are more highly differentiated than previously thought. On the other hand, recent findings in cat, opossum, and monkey reveal that the organization of supraspinal pathways in the Tegu lizard bears a striking resemblance to that observed in mammals.

Multiple pathways carry signals from short-wavelength-sensitive ('blue') cones to the middle temporal area of the macaque.

PubMed

Jayakumar, Jaikishan; Roy, Sujata; Dreher, Bogdan; Martin, Paul R; Vidyasagar, Trichur R

2013-01-01

We recorded spike activity of single neurones in the middle temporal visual cortical area (MT or V5) of anaesthetised macaque monkeys. We used flashing, stationary spatially circumscribed, cone-isolating and luminance-modulated stimuli of uniform fields to assess the effects of signals originating from the long-, medium- or short- (S) wavelength-sensitive cone classes. Nearly half (41/86) of the tested MT neurones responded reliably to S-cone-isolating stimuli. Response amplitude in the majority of the neurones tested further (19/28) was significantly reduced, though not always completely abolished, during reversible inactivation of visuotopically corresponding regions of the ipsilateral primary visual cortex (striate cortex, area V1). Thus, the present data indicate that signals originating in S-cones reach area MT, either via V1 or via a pathway that does not go through area V1. We did not find a significant difference between the mean latencies of spike responses of MT neurones to signals that bypass V1 and those that do not; the considerable overlap we observed precludes the use of spike-response latency as a criterion to define the routes through which the signals reach MT.

Temporal Progression of Visual Injury from Blast Exposure

DTIC Science & Technology

2016-09-01

significantly different levels of protein among the experimental groups and between the eye ipsilateral and contralateral to the injury in each animal...vitreous biomarkers from the experimental studies. We added additional animals to this group due to some concerns with the accuracy of a small...Scientific Interface 2007 Solomon R Pollack Award for Excellence in Graduate Bioengineering Research 2001-2003 Stephenson Fellowship Award 2000-2004

Increased expression of c-fos in the medial preoptic area after mating in male rats: role of afferent inputs from the medial amygdala and midbrain central tegmental field.

PubMed

Baum, M J; Everitt, B J

1992-10-01

Immunocytochemical methods were used to localize the protein product of the immediate-early gene, c-fos, in male rats after exposure to, or direct physical interaction with, oestrous females. Increasing amounts of physical contact with a female, with resultant olfactory-vomeronasal and/or genital-somatosensory inputs, caused corresponding increments in c-fos expression in the medial preoptic area, the caudal part of the bed nucleus of the stria terminalis, the medial amygdala, and the midbrain central tegmental field. Males bearing unilateral electrothermal lesions of the olfactory peduncle showed a significant reduction in c-fos expression in the ipsilateral medial amygdala, but not in other structures, provided their coital interaction with oestrous females was restricted to mount-thrust and occasional intromissive patterns due to repeated application of lidocaine anaesthetic to the penis. No such lateralization of c-fos expression occurred in other males with unilateral olfactory lesions which were allowed to intromit and ejaculate with a female. These results suggest that olfactory inputs, possibly of vomeronasal origin, contribute to the activation of c-fos in the medial amygdala. However, lesion-induced deficits in this type of afferent input to the nervous system appear to be readily compensated for by the genital somatosensory input derived from repeated intromissions. Unilateral excitotoxic lesions of the medial preoptic area, made by infusing quinolinic acid, failed to reduce c-fos expression in the ipsilateral or contralateral medial amygdala or central tegmental field following ejaculation. By contrast, combined, unilateral excitotoxic lesions of the medial amygdala and the central tegmental field significantly reduced c-fos expression in the ipsilateral bed nucleus of the stria terminalis and medial preoptic area after mating; no such asymmetry in c-fos expression occurred when lesions were restricted to either the medial amygdala or central tegmental field. This suggests that afferent inputs from the central tegmental field (probably of genital-somatosensory origin) and from the medial amygdala (probably of olfactory-vomeronasal origin) interact to promote cellular activity, and the resultant induction of c-fos, in the ipsilateral bed nucleus of the stria terminalis and medial preoptic area. The monitoring of neuronal c-fos expression provides an effective means of studying the role of sensory factors in governing the activity of integrated neural structures which control the expression of a complex social behaviour.

Retinal ganglion cell complex and peripapillary retinal nerve fiber layer thicknesses following carotid endarterectomy.

PubMed

Guclu, Orkut; Guclu, Hande; Huseyin, Serhat; Korkmaz, Selcuk; Yuksel, Volkan; Canbaz, Suat; Pelitli Gurlu, Vuslat

2018-06-23

To examine changes in retinal ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (RNFL) thicknesses by optical coherence tomography (OCT) in contralateral and ipsilatateral eyes of carotid artery stenosis (CAS) patients before and after carotid endarterectomy (CEA). Forty-two consecutive patients diagnosed with CAS (70-99% stenosis rate) who underwent CEA were included in this prospective cross-sectional study. The indication for CEA was based on the Asymptomatic Carotid Atherosclerosis Study. Doppler ultrasonography and computed tomography angiography were performed to calculate CAS. All the subjects underwent an ophthalmological examination, including best corrected visual acuity (BCVA), intraocular pressure (IOP) measurements, biomicroscopy, fundoscopy, and OCT before and after the surgery. The mean preoperative intraocular pressure was 15.2 ± 2.1 mmHg in the ipsilateral eye and 15.8 ± 2.7 in the contralateral eye. The mean postoperative intraocular pressure in the ipsilateral and contralateral eye was 18.6 ± 3.0 and 19.3 ± 3.8, respectively. The intraocular pressure was significantly higher in postoperative eyes (p = 0.0001). There was a statistically significant decrease in peripapillary RNFL thickness in superior quadrants postoperatively in ipsilateral eyes. The retinal GCC layer thickness was not significantly different before and after CEA in ipsilateral and contralateral eyes. Carotid endarterectomy results in thinning of the superior peripapillary RNFL thickness. To the best of our knowledge, this is the first study to examine peripapillary RNFL and GCC thicknesses before and after CEA.

Ultrafast dynamic contrast-enhanced mri of the breast using compressed sensing: breast cancer diagnosis based on separate visualization of breast arteries and veins.

PubMed

Onishi, Natsuko; Kataoka, Masako; Kanao, Shotaro; Sagawa, Hajime; Iima, Mami; Nickel, Marcel Dominik; Toi, Masakazu; Togashi, Kaori

2018-01-01

To evaluate the feasibility of ultrafast dynamic contrast-enhanced (UF-DCE) magnetic resonance imaging (MRI) with compressed sensing (CS) for the separate identification of breast arteries/veins and perform temporal evaluations of breast arteries and veins with a focus on the association with ipsilateral cancers. Our Institutional Review Board approved this study with retrospective design. Twenty-five female patients who underwent UF-DCE MRI at 3T were included. UF-DCE MRI consisting of 20 continuous frames was acquired using a prototype 3D gradient-echo volumetric interpolated breath-hold sequence including a CS reconstruction: temporal resolution, 3.65 sec/frame; spatial resolution, 0.9 × 1.3 × 2.5 mm. Two readers analyzed 19 maximum intensity projection images reconstructed from subtracted images, separately identified breast arteries/veins and the earliest frame in which they were respectively visualized, and calculated the time interval between arterial and venous visualization (A-V interval) for each breast. In total, 49 breasts including 31 lesions (breast cancer, 16; benign lesion, 15) were identified. In 39 of the 49 breasts (breasts with cancers, 16; breasts with benign lesions, 10; breasts with no lesions, 13), both breast arteries and veins were separately identified. The A-V intervals for breasts with cancers were significantly shorter than those for breasts with benign lesions (P = 0.043) and no lesions (P = 0.007). UF-DCE MRI using CS enables the separate identification of breast arteries/veins. Temporal evaluations calculating the time interval between arterial and venous visualization might be helpful in the differentiation of ipsilateral breast cancers from benign lesions. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:97-104. © 2017 International Society for Magnetic Resonance in Medicine.

Visual Aids for Improving Patient Decision Making in Severe Symptomatic Carotid Stenosis.

PubMed

Fridman, Sebastian; Saposnik, Gustavo; Sposato, Luciano A

2017-12-01

Because of the large amount of information to process and the limited time of a clinical consult, choosing between carotid endarterectomy (CEA) and carotid angioplasty with stenting (CAS) can be confusing for patients with severe symptomatic internal carotid stenosis (ICA). We aim to develop a visual aid tool to help clinicians and patients in the decision-making process of selecting between CEA and CAS. Based on pooled analysis from randomized controlled trials including patients with symptomatic and severe ICA (SSICA), we generated visual plots comparing CEA with CAS for 3 prespecified postprocedural time points: (1) any stroke or death at 4 months, and (2) any stroke or death in the first 30 days and ipsilateral stroke thereafter at 5 years and (3) at 10 years. A total of 4574 participants (2393 assigned to CAS, and 2361 to CEA) were included in the analyses. For every 100 patients with SSICA, 6 would develop any stroke or death in the CEA group compared with 9 undergoing CAS at 4 months (hazard ratio [HR] 1.53; 95%CI 1.20-1.95). At 5 years, 7 patients in the CEA group would develop any periprocedural stroke or death and ipsilateral stroke thereafter versus 12 undergoing CAS (HR 1.72; 95%CI 1.24-2.39), compared with 10 patients in the CEA and 13 in the CAS groups at 10 years (HR 1.17; 95%CI 0.82-1.66). Visual aids presented in this study could potentially help patients with severe symptomatic internal carotid stenosis to better weigh the risks and benefits of CEA versus CAS as a function of time, allowing for the prioritization of personal preferences, and should be prospectively assessed. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Abnormal functional motor lateralization in healthy siblings of patients with schizophrenia.

PubMed

Altamura, Mario; Fazio, Leonardo; De Salvia, Michela; Petito, Annamaria; Blasi, Giuseppe; Taurisano, Paolo; Romano, Raffaella; Gelao, Barbara; Bellomo, Antonello; Bertolino, Alessandro

2012-07-30

Earlier neuroimaging studies of motor function in schizophrenia have demonstrated reduced functional lateralization in the motor network during motor tasks. Here, we used event-related functional magnetic resonance imaging during a visually guided motor task in 18 clinically unaffected siblings of patients with schizophrenia and 24 matched controls to investigate if abnormal functional lateralization is related to genetic risk for this brain disorder. Whereas activity associated with motor task performance was mainly contralateral with only a marginal ipsilateral component in healthy participants, unaffected siblings had strong bilateral activity with significantly greater response in ipsilateral and contralateral premotor areas as well as in contralateral subcortical motor regions relative to controls. Reduced lateralization in siblings was also identified with a measure of laterality quotient. These findings suggest that abnormal functional lateralization of motor circuitry is related to genetic risk of schizophrenia. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

SU-E-P-14: Dosimetric Effects of Magnetic Field in MRI-Guided Radiation Therapy Delivery for Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, G; Currey, A; Li, X

2015-06-15

Purpose: MRI-guided radiation therapy (RT) delivery would be beneficial for breast irradiation. The electron return effect due to the presence of a transverse magnetic field (TMF) may cause dosimetric issues on dose on skin and at the lung-tissue interface. The purpose of this study is to investigate these issues. Methods: IMRT plans with tangential beams and VMAT plans with 200 degree arcs to cover ipsilateral breast were generated for 10 randomly selected breast cancer cases using a research planning system (Monaco, Elekta) utilizing Monte Carlo dose calculation with or without a TMF of 1.5 T. Plans were optimized to delivermore » uniform dose to the whole breast with an exclusion of 5 mm tissue under the skin (PTV-EVAL). All four plans for each patient were re-scaled to have the same PTV-EVAL volume to receive the same prescription dose. The skin is defined as the first 5 mm of ipsilateral-breast tissue, plus extensions in the surrounding region. Results: The presence of 1.5 T TMF resulted in (1)increased skin dose, with the mean and maximum skin dose increase of 5% and 9%, respectively; (2) similar dose homogeneity within the PTV-EVAL; (3) the slightly improved (3%) dose homogeneity in the whole breast; (4) Averages of 9 and 16% increases in V5 and V20, respectively, for ipsilateral lung; and (5) increased the mean heart dose by 34%. VMAT plans don’t improve whole breast dose uniformity as compared that to the tangential plans. Conclusion: The presence of transverse magnetic field in MRI-guided RT delivery for whole breast irradiation can Result in slightly improved dose homogeneity in the whole breast, increased dose to the ipsilateral lung, heart, and skin. Plan optimization with additional specific dose volume constraints may eliminate/reduce these dose increases. This work is partially supported by Elekta Inc.« less

Three-dimensional analysis of vestibular efferent neurons innervating semicircular canals of the gerbil

NASA Technical Reports Server (NTRS)

Purcell, I. M.; Perachio, A. A.

1997-01-01

Anterograde labeling techniques were used to examine peripheral innervation patterns of vestibular efferent neurons in the crista ampullares of the gerbil. Vestibular efferent neurons were labeled by extracellular injections of biocytin or biotinylated dextran amine into the contralateral or ipsilateral dorsal subgroup of efferent cell bodies (group e) located dorsolateral to the facial nerve genu. Anterogradely labeled efferent terminal field varicosities consist mainly of boutons en passant with fewer of the terminal type. The bouton swellings are located predominately in apposition to the basolateral borders of the afferent calyces and type II hair cells, but several boutons were identified close to the hair cell apical border on both types. Three-dimensional reconstruction and morphological analysis of the terminal fields from these cells located in the sensory neuroepithelium of the anterior, horizontal, and posterior cristae were performed. We show that efferent neurons densely innervate each end organ in widespread terminal fields. Subepithelial bifurcations of parent axons were minimal, with extensive collateralization occurring after the axons penetrated the basement membrane of the neuroepithelium. Axonal branching ranged between the 6th and 27th orders and terminal field collecting area far exceeds that of the peripheral terminals of primary afferent neurons. The terminal fields of the efferent neurons display three morphologically heterogeneous types: central, peripheral, and planum. All cell types possess terminal fields displaying a high degree of anisotropy with orientations typically parallel to or within +/-45 degrees of the longitudinal axis if the crista. Terminal fields of the central and planum zones predominately project medially toward the transverse axis from the more laterally located penetration of the basement membrane by the parent axon. Peripheral zone terminal fields extend predominately toward the planum semilunatum. The innervation areas of efferent terminal fields display a trend from smallest to largest for the central, peripheral, and planum types, respectively. Neurons that innervate the central zone of the crista do not extend into the peripheral or planum regions. Conversely, those neurons with terminal fields in the peripheral or planum regions do not innervate the central zone of the sensory neuroepithelium. The central zone of the crista is innervated preferentially by efferent neurons with cell bodies located in the ipsilateral group e. The peripheral and planum zones of the crista are innervated preferentially by efferent neurons with cell bodies located in the contralateral group e. A model incorporating our anatomic observations is presented describing an ipsilateral closed-loop feedback between ipsilateral efferent neurons and the periphery and an open-loop feed-forward innervation from contralateral efferent neurons. A possible role for the vestibular efferent neurons in the modulation of semicircular canal afferent response dynamics is proposed.

The nucleus of the optic tract. Its function in gaze stabilization and control of visual-vestibular interaction

NASA Technical Reports Server (NTRS)

Cohen, B.; Reisine, H.; Yokota, J. I.; Raphan, T.

1992-01-01

1. Electrical stimulation of the nucleus of the optic tract (NOT) induced nystagmus and after-nystagmus with ipsilateral slow phases. The velocity characteristics of the nystagmus were similar to those of the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN), both of which are produced by velocity storage in the vestibular system. When NOT was destroyed, these components disappeared. This indicates that velocity storage is activated from the visual system through NOT. 2. Velocity storage produces compensatory eye-in-head and head-on-body movements through the vestibular system. The association of NOT with velocity storage implies that NOT helps stabilize gaze in space during both passive motion and active locomotion in light with an angular component. It has been suggested that "vestibular-only" neurons in the vestibular nuclei play an important role in generation of velocity storage. Similarities between the rise and fall times of eye velocity during OKN and OKAN to firing rates of vestibular-only neurons suggest that these cells may receive their visual input through NOT. 3. One NOT was injected with muscimol, a GABAA agonist. Ipsilateral OKN and OKAN were lost, suggesting that GABA, which is an inhibitory transmitter in NOT, acts on projection pathways to the brain stem. A striking finding was that visual suppression and habituation of contralateral slow phases of vestibular nystagmus were also abolished after muscimol injection. The latter implies that NOT plays an important role in producing visual suppression of the VOR and habituating its time constant. 4. Habituation is lost after nodulus and uvula lesions and visual suppression after lesions of the flocculus and paraflocculus. We postulate that the disappearance of vestibular habituation and of visual suppression of vestibular responses after muscimol injections was due to dysfacilitation of the prominent NOT-inferior olive pathway, inactivating climbing fibers from the dorsal cap to nodulouvular and flocculoparafloccular Purkinje cells. The prompt loss of habituation when NOT was inactivated, and its return when the GABAergic inhibition dissipated, suggests that although VOR habituation can be relatively permanent, it must be maintained continuously by activity of the vestibulocerebellum.

The role of oscillatory brain activity in object processing and figure-ground segmentation in human vision.

PubMed

Kinsey, K; Anderson, S J; Hadjipapas, A; Holliday, I E

2011-03-01

The perception of an object as a single entity within a visual scene requires that its features are bound together and segregated from the background and/or other objects. Here, we used magnetoencephalography (MEG) to assess the hypothesis that coherent percepts may arise from the synchronized high frequency (gamma) activity between neurons that code features of the same object. We also assessed the role of low frequency (alpha, beta) activity in object processing. The target stimulus (i.e. object) was a small patch of a concentric grating of 3c/°, viewed eccentrically. The background stimulus was either a blank field or a concentric grating of 3c/° periodicity, viewed centrally. With patterned backgrounds, the target stimulus emerged--through rotation about its own centre--as a circular subsection of the background. Data were acquired using a 275-channel whole-head MEG system and analyzed using Synthetic Aperture Magnetometry (SAM), which allows one to generate images of task-related cortical oscillatory power changes within specific frequency bands. Significant oscillatory activity across a broad range of frequencies was evident at the V1/V2 border, and subsequent analyses were based on a virtual electrode at this location. When the target was presented in isolation, we observed that: (i) contralateral stimulation yielded a sustained power increase in gamma activity; and (ii) both contra- and ipsilateral stimulation yielded near identical transient power changes in alpha (and beta) activity. When the target was presented against a patterned background, we observed that: (i) contralateral stimulation yielded an increase in high-gamma (>55 Hz) power together with a decrease in low-gamma (40-55 Hz) power; and (ii) both contra- and ipsilateral stimulation yielded a transient decrease in alpha (and beta) activity, though the reduction tended to be greatest for contralateral stimulation. The opposing power changes across different regions of the gamma spectrum with 'figure/ground' stimulation suggest a possible dual role for gamma rhythms in visual object coding, and provide general support of the binding-by-synchronization hypothesis. As the power changes in alpha and beta activity were largely independent of the spatial location of the target, however, we conclude that their role in object processing may relate principally to changes in visual attention. Copyright © 2010 Elsevier B.V. All rights reserved.

Topographic organization, number, and laminar distribution of callosal cells connecting visual cortical areas 17 and 18 of normally pigmented and Siamese cats.

PubMed

Berman, N E; Grant, S

1992-07-01

The callosal connections between visual cortical areas 17 and 18 in adult normally pigmented and "Boston" Siamese cats were studied using degeneration methods, and by transport of WGA-HRP combined with electrophysiological mapping. In normal cats, over 90% of callosal neurons were located in the supragranular layers. The supragranular callosal cell zone spanned the area 17/18 border and extended, on average, some 2-3 mm into both areas to occupy a territory which was roughly co-extensive with the distribution of callosal terminations in these areas. The region of the visual field adjoining the vertical meridian that was represented by neurons in the supragranular callosal cell zone was shown to increase systematically with decreasing visual elevation. Thus, close to the area centralis, receptive-field centers recorded from within this zone extended only up to 5 deg into the contralateral hemifield but at elevations of -10 deg and -40 deg they extended as far as 8 deg and 14 deg, respectively, into this hemifield. This suggests an element of visual non-correspondence in the callosal pathway between these cortical areas, which may be an essential substrate for "coarse" stereopsis at the visual midline. In the Siamese cats, the callosal cell and termination zones in areas 17 and 18 were expanded in width compared to the normal animals, but the major components were less robust. The area 17/18 border was often devoid of callosal axons and, in particular, the number of supragranular layer neurons participating in the pathway were drastically reduced, to only about 25% of those found in the normally pigmented adults. The callosal zones contained representations of the contralateral and ipsilateral hemifields that were roughly mirror-symmetric about the vertical meridian, and both hemifield representations increased with decreasing visual elevation. The extent and severity of the anomalies observed were similar across individual cats, regardless of whether a strabismus was also present. The callosal pathway between these visual cortical areas in the Siamese cat has been considered "silent," since nearly all neurons within its territory are activated only by the contralateral eye. The paucity of supragranular pyramidal neurons involved in the pathway may explain this silence.

Functions of the nucleus of the optic tract (NOT)

PubMed Central

Yakushin, Sergei B.; Gizzi, Martin; Reisine, Harvey; Raphan, Theodore; Büttner-Ennever, Jean; Cohen, Bernard

2007-01-01

Ocular pursuit in monkeys, elicited by sinusoidal and triangular (constant velocity) stimuli, was studied before and after lesions of the nucleus of the optic tract (NOT). Before NOT lesions, pursuit gains (eye velocity/target velocity) were close to unity for sinusoidal and constant-velocity stimuli at frequencies up to 1 Hz. In this range, retinal slip was less than 2°. Electrode tracks made to identify the location of NOT caused deficits in ipsilateral pursuit, which later recovered. Small electrolytic lesions of NOT reduced ipsilateral pursuit gains to below 0.5 in all tested conditions. Pursuit was better, however, when the eyes moved from the contra-lateral side toward the center (centripetal pursuit) than from the center ipsilaterally (centrifugal pursuit), although the eyes remained in close proximity to the target with saccadic tracking. Effects of lesions on ipsilateral pursuit were not permanent, and pursuit gains had generally recovered to 60–80% of baseline after about 2 weeks. One animal had bilateral NOT lesions and lost pursuit for 4 days. Thereafter, it had a centrifugal pursuit deficit that lasted for more than 2 months. Vertical pursuit and visually guided saccades were not affected by the bilateral NOT lesions in this animal. We also compared effects of these and similar NOT lesions on opto-kinetic nystagmus (OKN) and optokinetic after-nystagmus (OKAN). Correlation of functional deficits with NOT lesions from this and previous studies showed that rostral lesions of NOT in and around the pretectal oli-vary nucleus, which interrupted cortical input through the brachium of the superior colliculus (BSC), affected both smooth pursuit and OKN. In two animals in which it was tested, NOT lesions that caused a deficit in pursuit also decreased the rapid and slow components of OKN slow-phase velocity and affected OKAN. It was previously shown that slightly more caudal NOT lesions were more effective in altering gain adaptation of the angular vestibulo-ocular relfex (aVOR). The present findings suggest that cortical pathways through rostral NOT play an important role in maintenance of ipsilateral ocular pursuit. Since lesions that affected ocular pursuit had similar effects on ipsilateral OKN, processing for these two functions is probably closely linked in NOT, as it is elsewhere. PMID:10803412

Magnetoencephalographic study of hand and foot sensorimotor organization in 325 consecutive patients evaluated for tumor or epilepsy surgery

PubMed Central

Willemse, Ronald B.; Hillebrand, Arjan; Ronner, Hanneke E.; Peter Vandertop, W.; Stam, Cornelis J.

2015-01-01

Objectives The presence of intracranial lesions or epilepsy may lead to functional reorganization and hemispheric lateralization. We applied a clinical magnetoencephalography (MEG) protocol for the localization of the contralateral and ipsilateral S1 and M1 of the foot and hand in patients with non-lesional epilepsy, stroke, developmental brain injury, traumatic brain injury and brain tumors. We investigated whether differences in activation patterns could be related to underlying pathology. Methods Using dipole fitting, we localized the sources underlying sensory and motor evoked magnetic fields (SEFs and MEFs) of both hands and feet following unilateral stimulation of the median nerve (MN) and posterior tibial nerve (PTN) in 325 consecutive patients. The primary motor cortex was localized using beamforming following a self-paced repetitive motor task for each hand and foot. Results The success rate for motor and sensory localization for the feet was significantly lower than for the hands (motor_hand 94.6% versus motor_feet 81.8%, p < 0.001; sensory_hand 95.3% versus sensory_feet 76.0%, p < 0.001). MN and PTN stimulation activated 86.6% in the contralateral S1, with ipsilateral activation < 0.5%. Motor cortex activation localized contralaterally in 76.1% (5.2% ipsilateral, 7.6% bilateral and 11.1% failures) of all motor MEG recordings. The ipsilateral motor responses were found in 43 (14%) out of 308 patients with motor recordings (range: 8.3–50%, depending on the underlying pathology), and had a higher occurrence in the foot than in the hand (motor_foot 44.8% versus motor_hand 29.6%, p = 0.031). Ipsilateral motor responses tended to be more frequent in patients with a history of stroke, traumatic brain injury (TBI) or developmental brain lesions (p = 0.063). Conclusions MEG localization of sensorimotor cortex activation was more successful for the hand compared to the foot. In patients with neural lesions, there were signs of brain reorganization as measured by more frequent ipsilateral motor cortical activation of the foot in addition to the traditional sensory and motor activation patterns in the contralateral hemisphere. The presence of ipsilateral neural reorganization, especially around the foot motor area, suggests that careful mapping of the hand and foot in both contralateral and ipsilateral hemispheres prior to surgery might minimize postoperative deficits. PMID:26693401

Predicting pain relief: Use of pre-surgical trigeminal nerve diffusion metrics in trigeminal neuralgia.

PubMed

Hung, Peter S-P; Chen, David Q; Davis, Karen D; Zhong, Jidan; Hodaie, Mojgan

2017-01-01

Trigeminal neuralgia (TN) is a chronic neuropathic facial pain disorder that commonly responds to surgery. A proportion of patients, however, do not benefit and suffer ongoing pain. There are currently no imaging tools that permit the prediction of treatment response. To address this paucity, we used diffusion tensor imaging (DTI) to determine whether pre-surgical trigeminal nerve microstructural diffusivities can prognosticate response to TN treatment. In 31 TN patients and 16 healthy controls, multi-tensor tractography was used to extract DTI-derived metrics-axial (AD), radial (RD), mean diffusivity (MD), and fractional anisotropy (FA)-from the cisternal segment, root entry zone and pontine segment of trigeminal nerves for false discovery rate-corrected Student's t -tests. Ipsilateral diffusivities were bootstrap resampled to visualize group-level diffusivity thresholds of long-term response. To obtain an individual-level statistical classifier of surgical response, we conducted discriminant function analysis (DFA) with the type of surgery chosen alongside ipsilateral measurements and ipsilateral/contralateral ratios of AD and RD from all regions of interest as prediction variables. Abnormal diffusivity in the trigeminal pontine fibers, demonstrated by increased AD, highlighted non-responders (n = 14) compared to controls. Bootstrap resampling revealed three ipsilateral diffusivity thresholds of response-pontine AD, MD, cisternal FA-separating 85% of non-responders from responders. DFA produced an 83.9% (71.0% using leave-one-out-cross-validation) accurate prognosticator of response that successfully identified 12/14 non-responders. Our study demonstrates that pre-surgical DTI metrics can serve as a highly predictive, individualized tool to prognosticate surgical response. We further highlight abnormal pontine segment diffusivities as key features of treatment non-response and confirm the axiom that central pain does not commonly benefit from peripheral treatments.

Pantomime to visual presentation of objects: left hand dyspraxia in patients with complete callosotomy.

PubMed

Lausberg, Hedda; Cruz, Robyn F; Kita, Sotaro; Zaidel, Eran; Ptito, Alain

2003-02-01

Investigations of left hand praxis in imitation and object use in patients with callosal disconnection have yielded divergent results, inducing a debate between two theoretical positions. Whereas Liepmann suggested that the left hemisphere is motor dominant, others maintain that both hemispheres have equal motor competences and propose that left hand apraxia in patients with callosal disconnection is secondary to left hemispheric specialization for language or other task modalities. The present study aims to gain further insight into the motor competence of the right hemisphere by investigating pantomime of object use in split-brain patients. Three patients with complete callosotomy and, as control groups, five patients with partial callosotomy and nine healthy subjects were examined for their ability to pantomime object use to visual object presentation and demonstrate object manipulation. In each condition, 11 objects were presented to the subjects who pantomimed or demonstrated the object use with either hand. In addition, six object pairs were presented to test bimanual coordination. Two independent raters evaluated the videotaped movement demonstrations. While object use demonstrations were perfect in all three groups, the split-brain patients displayed apraxic errors only with their left hands in the pantomime condition. The movement analysis of concept and execution errors included the examination of ipsilateral versus contralateral motor control. As the right hand/left hemisphere performances demonstrated retrieval of the correct movement concepts, concept errors by the left hand were taken as evidence for right hemisphere control. Several types of execution errors reflected a lack of distal motor control indicating the use of ipsilateral pathways. While one split-brain patient controlled his left hand predominantly by ipsilateral pathways in the pantomime condition, the error profile in the other two split-brain patients suggested that the right hemisphere controlled their left hands. In the object use condition, in all three split-brain patients fine-graded distal movements in the left hand indicated right hemispheric control. Our data show left hand apraxia in split-brain patients is not limited to verbal commands, but also occurs in pantomime to visual presentation of objects. As the demonstration with object in hand was unimpaired in either hand, both hemispheres must contain movement concepts for object use. However, the disconnected right hemisphere is impaired in retrieving the movement concept in response to visual object presentation, presumably because of a deficit in associating perceptual object representation with the movement concepts.

Public Perception of the Burden of Microtia.

PubMed

Byun, Stephanie; Hong, Paul; Bezuhly, Michael

2016-10-01

Microtia is associated with psychosocial burden and stigma. The authors' objective was to determine the potential impact of being born with microtia by using validated health state utility assessment measures. An online utility assessment using visual analogue scale, time tradeoff, and standard gamble was used to determine utilities for microtia with or without ipsilateral deafness, monocular blindness, and binocular blindness from a prospective sample of the general population. Utility scores were compared between health states using Wilcoxon and Kruskal-Wallis tests. Univariate regression was performed using sex, age, race, and education as independent predictors of utility scores. Over a 6-month enrollment period, 104 participants were included in the analysis. Visual analogue scale (median 0.80, interquartile range [0.72-0.85]), time tradeoff (0.88 [0.77-0.91]), and standard gamble (0.91 [0.84-0.97]) scores for microtia with ipsilateral deafness were higher (P <0.01) than those of binocular blindness (visual analogue scale, 0.30 [0.20-0.45]; time tradeoff, 0.42 [0.17-0.67]; and standard gamble, 0.52 [0.36-0.78]). Time trade-off scores for microtia with deafness were not different from monocular blindness (0.83 [0.67-0.91]). Higher level of education was associated with higher time tradeoff and standard gamble scores for microtia with or without deafness (P <0.05). Using objective health state utility scores, the current study demonstrates that the perceived burden of microtia with or without deafness is no different or less than monocular blindness. Given high utility scores for microtia, delaying autologous reconstruction beyond school entrance age may be justified.

Fractionated Stereotactic Radiotherapy in Patients With Optic Nerve Sheath Meningioma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paulsen, Frank, E-mail: frank.paulsen@med.uni-tuebingen.de; Doerr, Stefan; Wilhelm, Helmut

Purpose: To evaluate the effectiveness of fractionated stereotactic radiotherapy (SFRT) in the treatment of optic nerve sheath meningioma (ONSM). Methods and Materials: Between 1993 and 2005, 109 patients (113 eyes) with primary (n = 37) or secondary (n = 76) ONSM were treated according to a prospective protocol with SFRT to a median dose of 54 Gy. All patients underwent radiographic, ophthalmologic, and endocrine analysis before and after SFRT. Radiographic response, visual control, and late side effects were endpoints of the analysis. Results: Median time to last clinical, radiographic, and ophthalmologic follow up was 30.2 months (n = 113), 42.7more » months (n = 108), and 53.7 months (n = 91), respectively. Regression of the tumor was observed in 5 eyes and progression in 4 eyes, whereas 104 remained stable. Visual acuity improved in 12, deteriorated in 11, and remained stable in 68 eyes. Mean visual field defects reduced from 33.6% (n = 90) to 17.8% (n = 56) in ipsilateral and from 10% (n = 94) to 6.7% (n = 62) in contralateral eyes. Ocular motility improved in 23, remained stable in 65, and deteriorated in 3 eyes. Radiographic tumor control was 100% at 3 years and 98% at 5 years. Visual acuity was preserved in 94.8% after 3 years and in 90.9% after 5 years. Endocrine function was normal in 90.8% after 3 years and in 81.3% after 5 years. Conclusions: SFRT represents a highly effective treatment for ONSM. Interdisciplinary counseling of the patients is recommended. Because of the high rate of preservation of visual acuity we consider SFRT the standard approach for the treatment of ONSM. Prolonged observation is warranted to more accurately assess late visual impairment. Moderate de-escalation of the radiation dose might improve the preservation of visual acuity and pituitary gland function.« less

Transcutaneous Electrical Nerve Stimulation Reduces Post-Thoractomy Ipsilateral Shoulder Pain. A Prospective Randomized Study.

PubMed

Esteban González, Pedro; Novoa, Nuria M; Varela, Gonzalo

2015-12-01

The patient's position during an axillary thoracotomy can cause postoperative pain and decrease mobility of the ipsilateral shoulder. In this study, we assessed whether the implementation of a standardized analgesia program using transcutaneous electrical nerve stimulation (TENS) decreases local pain and improves ipsilateral shoulder mobility. Randomized, single-blind, single-center clinical trial of 50 patients who had undergone anatomical lung resection via axillary muscle-sparing thoracotomy. Patients were treated with TENS devices for 30 minutes every 8 hours, beginning on postoperative day 1. Pain and mobility of the affected limb were recorded at the same time on postoperative days 1 through 3. A visual analogue scale was used for pain assessment and shoulder mobility was assessed with a goniometer. Results were compared using a non-parametric test. Twenty-five patients were randomized to each group. Mean age of the control group was 62.7±9.3 years and 63.4±10.2 years in the experimental group. Shoulder mobility parameters were similar in both groups on all postoperative days. However, pain during flexion significantly decreased on day 2 (P=.03) and day 3 (P=.04) in the experimental group. The use of TENS decreases pain from shoulder flexion in patients undergoing axillary thoracotomy for pulmonary resection. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.

Temporal kinetics of prefrontal modulation of the extrastriate cortex during visual attention.

PubMed

Yago, Elena; Duarte, Audrey; Wong, Ting; Barceló, Francisco; Knight, Robert T

2004-12-01

Single-unit, event-related potential (ERP), and neuroimaging studies have implicated the prefrontal cortex (PFC) in top-down control of attention and working memory. We conducted an experiment in patients with unilateral PFC damage (n = 8) to assess the temporal kinetics of PFC-extrastriate interactions during visual attention. Subjects alternated attention between the left and the right hemifields in successive runs while they detected target stimuli embedded in streams of repetitive task-irrelevant stimuli (standards). The design enabled us to examine tonic (spatial selection) and phasic (feature selection) PFC-extrastriate interactions. PFC damage impaired performance in the visual field contralateral to lesions, as manifested by both larger reaction times and error rates. Assessment of the extrastriate P1 ERP revealed that the PFC exerts a tonic (spatial selection) excitatory input to the ipsilateral extrastriate cortex as early as 100 msec post stimulus delivery. The PFC exerts a second phasic (feature selection) excitatory extrastriate modulation from 180 to 300 msec, as evidenced by reductions in selection negativity after damage. Finally, reductions of the N2 ERP to target stimuli supports the notion that the PFC exerts a third phasic (target selection) signal necessary for successful template matching during postselection analysis of target features. The results provide electrophysiological evidence of three distinct tonic and phasic PFC inputs to the extrastriate cortex in the initial few hundred milliseconds of stimulus processing. Damage to this network appears to underlie the pervasive deficits in attention observed in patients with prefrontal lesions.

Behavioral Investigation on the Frames of Reference Involved in Visuomotor Transformations during Peripheral Arm Reaching

PubMed Central

Pelle, Gina; Perrucci, Mauro Gianni; Galati, Gaspare; Fattori, Patrizia; Galletti, Claudio; Committeri, Giorgia

2012-01-01

Background Several psychophysical experiments found evidence for the involvement of gaze-centered and/or body-centered coordinates in arm-movement planning and execution. Here we aimed at investigating the frames of reference involved in the visuomotor transformations for reaching towards visual targets in space by taking target eccentricity and performing hand into account. Methodology/Principal Findings We examined several performance measures while subjects reached, in complete darkness, memorized targets situated at different locations relative to the gaze and/or to the body, thus distinguishing between an eye-centered and a body-centered frame of reference involved in the computation of the movement vector. The errors seem to be mainly affected by the visual hemifield of the target, independently from its location relative to the body, with an overestimation error in the horizontal reaching dimension (retinal exaggeration effect). The use of several target locations within the perifoveal visual field allowed us to reveal a novel finding, that is, a positive linear correlation between horizontal overestimation errors and target retinal eccentricity. In addition, we found an independent influence of the performing hand on the visuomotor transformation process, with each hand misreaching towards the ipsilateral side. Conclusions While supporting the existence of an internal mechanism of target-effector integration in multiple frames of reference, the present data, especially the linear overshoot at small target eccentricities, clearly indicate the primary role of gaze-centered coding of target location in the visuomotor transformation for reaching. PMID:23272180

Radical resection of a Shamblin type III carotid body tumour without cerebro-neurological deficit: Improved technique with preoperative embolization and carotid stenting.

PubMed

Ong, H S; Fan, X D; Ji, T

2014-12-01

The surgical resection of a large unfavourable Shamblin type III carotid body tumour (CBT) can be very challenging technically, with many potential significant complications. Preoperative embolization aids in shrinking the lesion, reducing intraoperative blood loss, and improving visualization of the surgical field. Preoperative internal carotid artery (ICA) stenting aids in reinforcing the arterial wall, thereby providing a better dissection plane. A woman presented to our institution with a large right-sided CBT. Failure of the preoperative temporary balloon occlusion (TBO) test emphasized the importance of intraoperative preservation of the ipsilateral ICA. A combination of both preoperative embolization and carotid stenting allowed a less hazardous radical resection of the CBT. An almost bloodless surgical field permitted meticulous dissection, hence reducing the risk of intraoperative vascular and nerve injury. Embolization and carotid stenting prior to surgical resection should be considered in cases with bilateral CBT or a skull base orientated high CBT, and for those with intracranial extension and patients who have failed the TBO test. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Dissociated α-band modulations in the dorsal and ventral visual pathways in visuospatial attention and perception.

PubMed

Capilla, Almudena; Schoffelen, Jan-Mathijs; Paterson, Gavin; Thut, Gregor; Gross, Joachim

2014-02-01

Modulations of occipito-parietal α-band (8-14 Hz) power that are opposite in direction (α-enhancement vs. α-suppression) and origin of generation (ipsilateral vs. contralateral to the locus of attention) are a robust correlate of anticipatory visuospatial attention. Yet, the neural generators of these α-band modulations, their interdependence across homotopic areas, and their respective contribution to subsequent perception remain unclear. To shed light on these questions, we employed magnetoencephalography, while human volunteers performed a spatially cued detection task. Replicating previous findings, we found α-power enhancement ipsilateral to the attended hemifield and contralateral α-suppression over occipito-parietal sensors. Source localization (beamforming) analysis showed that α-enhancement and suppression were generated in 2 distinct brain regions, located in the dorsal and ventral visual streams, respectively. Moreover, α-enhancement and suppression showed different dynamics and contribution to perception. In contrast to the initial and transient dorsal α-enhancement, α-suppression in ventro-lateral occipital cortex was sustained and influenced subsequent target detection. This anticipatory biasing of ventro-lateral extrastriate α-activity probably reflects increased receptivity in the brain region specialized in processing upcoming target features. Our results add to current models on the role of α-oscillations in attention orienting by showing that α-enhancement and suppression can be dissociated in time, space, and perceptual relevance.

Cooperative processing in primary somatosensory cortex and posterior parietal cortex during tactile working memory.

PubMed

Ku, Yixuan; Zhao, Di; Bodner, Mark; Zhou, Yong-Di

2015-08-01

In the present study, causal roles of both the primary somatosensory cortex (SI) and the posterior parietal cortex (PPC) were investigated in a tactile unimodal working memory (WM) task. Individual magnetic resonance imaging-based single-pulse transcranial magnetic stimulation (spTMS) was applied, respectively, to the left SI (ipsilateral to tactile stimuli), right SI (contralateral to tactile stimuli) and right PPC (contralateral to tactile stimuli), while human participants were performing a tactile-tactile unimodal delayed matching-to-sample task. The time points of spTMS were 300, 600 and 900 ms after the onset of the tactile sample stimulus (duration: 200 ms). Compared with ipsilateral SI, application of spTMS over either contralateral SI or contralateral PPC at those time points significantly impaired the accuracy of task performance. Meanwhile, the deterioration in accuracy did not vary with the stimulating time points. Together, these results indicate that the tactile information is processed cooperatively by SI and PPC in the same hemisphere, starting from the early delay of the tactile unimodal WM task. This pattern of processing of tactile information is different from the pattern in tactile-visual cross-modal WM. In a tactile-visual cross-modal WM task, SI and PPC contribute to the processing sequentially, suggesting a process of sensory information transfer during the early delay between modalities. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Source localization of small sharp spikes: low resolution electromagnetic tomography (LORETA) reveals two distinct cortical sources.

PubMed

Zumsteg, Dominik; Andrade, Danielle M; Wennberg, Richard A

2006-06-01

We have investigated the cortical sources and electroencephalographic (EEG) characteristics of small sharp spikes (SSS) by using statistical non-parametric mapping (SNPM) of low resolution electromagnetic tomography (LORETA). We analyzed 7 SSS patterns (501 individual SSS) in 6 patients who underwent sleep EEG studies with 29 or 23 scalp electrodes. The scalp signals were averaged time-locked to the SSS peak activity and subjected to SNPM of LORETA values. All 7 SSS patterns (mean 72 individual SSS, range 11-200) revealed a very similar and highly characteristic transhemispheric oblique scalp voltage distribution comprising a first negative field maximum over ipsilateral lateral temporal areas, followed by a second negative field maximum over the contralateral subtemporal region approximately 30 ms later. SNPM-LORETA consistently localized the first component into the ipsilateral posterior insular region, and the second component into ipsilateral posterior mesial temporo-occipital structures. SSS comprise an amalgam of two sequential, distinct cortical components, showing a very uniform and peculiar EEG pattern and cortical source solutions. As such, they must be clearly distinguished from interictal epileptiform discharges in patients with epilepsy. The awareness of these peculiar EEG characteristics may increase our ability to differentiate SSS from interictal epileptiform activity. The finding of a posterior insular source might serve as an inspiration for new physiological considerations regarding these enigmatic waveforms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ng, Sweet Ping, E-mail: sweet.ng@petermac.org; David, Steven; Alamgeer, Muhammad

Purpose: To assess the diagnostic performance of pretreatment {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) and its impact on radiation therapy treatment decisions in patients with locally advanced breast cancer (LABC). Methods and Materials: Patients with LABC with Eastern Cooperative Oncology Group performance status <2 and no contraindication to neoadjuvant chemotherapy, surgery, and adjuvant radiation therapy were enrolled on a prospective trial. All patients had pretreatment conventional imaging (CI) performed, including bilateral breast mammography and ultrasound, bone scan, and CT chest, abdomen, and pelvis scans performed. Informed consent was obtained before enrolment. Pretreatment whole-body {sup 18}F-FDG PET/CT scansmore » were performed on all patients, and results were compared with CI findings. Results: A total of 154 patients with LABC with no clinical or radiologic evidence of distant metastases on CI were enrolled. Median age was 49 years (range, 26-70 years). Imaging with PET/CT detected distant metastatic disease and/or locoregional disease not visualized on CI in 32 patients (20.8%). Distant metastatic disease was detected in 17 patients (11.0%): 6 had bony metastases, 5 had intrathoracic metastases (pulmonary/mediastinal), 2 had distant nodal metastases, 2 had liver metastases, 1 had pulmonary and bony metastases, and 1 had mediastinal and distant nodal metastases. Of the remaining 139 patients, nodal disease outside conventional radiation therapy fields was detected on PET/CT in 15 patients (10.8%), with involvement of ipsilateral internal mammary nodes in 13 and ipsilateral level 5 cervical nodes in 2. Conclusions: Imaging with PET/CT provides superior diagnostic and staging information in patients with LABC compared with CI, which has significant therapeutic implications with respect to radiation therapy management. Imaging with PET/CT should be considered in all patients undergoing primary staging for LABC.« less

Spine surgeon's kinematics during discectomy, part II: operating table height and visualization methods, including microscope.

PubMed

Park, Jeong Yoon; Kim, Kyung Hyun; Kuh, Sung Uk; Chin, Dong Kyu; Kim, Keun Su; Cho, Yong Eun

2014-05-01

Surgeon spine angle during surgery was studied ergonomically and the kinematics of the surgeon's spine was related with musculoskeletal fatigue and pain. Spine angles varied depending on operation table height and visualization method, and in a previous paper we showed that the use of a loupe and a table height at the midpoint between the umbilicus and the sternum are optimal for reducing musculoskeletal loading. However, no studies have previously included a microscope as a possible visualization method. The objective of this study is to assess differences in surgeon spine angles depending on operating table height and visualization method, including microscope. We enrolled 18 experienced spine surgeons for this study, who each performed a discectomy using a spine surgery simulator. Three different methods were used to visualize the surgical field (naked eye, loupe, microscope) and three different operating table heights (anterior superior iliac spine, umbilicus, the midpoint between the umbilicus and the sternum) were studied. Whole spine angles were compared for three different views during the discectomy simulation: midline, ipsilateral, and contralateral. A 16-camera optoelectronic motion analysis system was used, and 16 markers were placed from the head to the pelvis. Lumbar lordosis, thoracic kyphosis, cervical lordosis, and occipital angle were compared between the different operating table heights and visualization methods as well as a natural standing position. Whole spine angles differed significantly depending on visualization method. All parameters were closer to natural standing values when discectomy was performed with a microscope, and there were no differences between the naked eye and the loupe. Whole spine angles were also found to differ from the natural standing position depending on operating table height, and became closer to natural standing position values as the operating table height increased, independent of the visualization method. When using a microscope, lumbar lordosis, thoracic kyphosis, and cervical lordosis showed no differences according to table heights above the umbilicus. This study suggests that the use of a microscope and a table height above the umbilicus are optimal for reducing surgeon musculoskeletal fatigue.

Electric-acoustic stimulation suppresses tinnitus in a subject with high-frequency single-sided deafness.

PubMed

Mertens, Griet; Van Rompaey, Vincent; Van de Heyning, Paul

2018-05-17

A suggested solution to suppress tinnitus is to restore the normal sensory input. This is based on the auditory deprivation hypothesis. It is known that hearing aids can provide sufficient activation of the auditory nervous system and reduce tinnitus in subjects with mild to moderate hearing loss and that cochlear implantation can reduce tinnitus in subjects with severe to profound hearing loss. This applies to subjects with single-sided deafness (SSD) or bilateral hearing loss. To investigate if electric-acoustic stimulation (EAS) can reduce severe tinnitus in a subject with residual hearing in the ipsilateral ear and contralateral normal hearing (high-frequency SSD) by restoring the auditory input. Tinnitus reduction was investigated for 1 year after implantation in a subject with high-frequency SSD, who uses EAS, and was compared to 11 subjects with a cochlear implant (CI) with SSD. The Visual Analogue Scale (VAS) and the Tinnitus Questionnaire (TQ) were administered pre-operatively and at 1, 3, 6, and 12 months after implantation. Significant tinnitus reduction was observed 1 month after implantation on the VAS in the subjects with SSD using a CI. Tinnitus reduction was also observed in the subject with high-frequency SSD using EAS. A further decrease was observed 3 months after implantation. The TQ and VAS scores remained stable up to 1 year after implantation. A CI can significantly reduce ipsilateral severe tinnitus in a subject with SSD. Ipsilateral severe tinnitus can also be reduced using EAS in subjects with high-frequency SSD.

Fluoroscopically guided infiltration of the cervical nerve root: an indirect approach through the ipsilateral facet joint.

PubMed

Kelekis, Alexios; Filippiadis, Dimitrios K; Velonakis, Georgios; Martin, Jean-Baptist; Oikonomopoulos, Nikolaos; Brountzos, Elias; Kelekis, Nikolaos

2014-01-01

Transforaminal infiltrations in the cervical spine are governed by a higher rate of vascular puncture than in the lumbar spine. The purpose of our study is to assess the safety and efficacy of percutaneous, fluoroscopically guided nerve root infiltrations in cases of cervical radiculopathy. An indirect postero-lateral approach was performed through the ipsilateral facet joint. During the last 2 years, 25 patients experiencing cervical radiculopathy underwent percutaneous, fluoroscopically guided nerve root infiltrations by means of an indirect postero-lateral approach through the ipsilateral facet joint. The intra-articular position of the needle (22-gauge spinal needle) was fluoroscopically verified after injection of a small amount of contrast medium which also verified dispersion of the contrast medium periradicularly and in the epidural space. Then a mixture of long-acting glucocorticosteroid diluted in normal saline (1.5/1 mL) was injected intra-articularly. A questionnaire with a Numeric Visual Scale (NVS) scale helped assess pain relief, life quality, and mobility improvement. A mean of 2.3 sessions was performed in the patients of our study. In the vast majority of our patients 19/25 (76%), the second infiltration was performed within 7-10 days of the first one. Comparing the pain scores prior (mean value 8.80 ± 1.080 NVS units) and after (mean value 1.84 ± 1.405 NVS units), there was a mean decrease of 6.96 ± 1.695 NVS units [median value 7 NVS units (P < 0.001) in terms of pain reduction, effect upon mobility, and life quality. There were no clinically significant complications noted in our study. Fluoroscopically guided transforaminal infiltrations through the ipsilateral facet joint seem to be a feasible, efficacious, and safe approach for the treatment of patients with cervical radiculopathy. This approach facilitates needle placement and minimizes risk of complications.

Healthy-side dominance of middle- and long-latency neuromagnetic fields in idiopathic sudden sensorineural hearing loss.

PubMed

Li, L P H; Shiao, A S; Chen, L F; Niddam, D M; Chang, S Y; Lien, C F; Lee, S K; Hsieh, J C

2006-08-01

Any lesion along the neural axis may induce a subsequent functional reorganization at the level above. The present study used magnetoencephalography to investigate auditory-evoked magnetic fields [a component of the middle-latency auditory evoked fields peaking at approximately 50 ms (P50m) and a component of the long-latency auditory evoked fields peaking at approximately 100 ms (N100m)] on stimulation of both healthy and affected ears in patients with acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL) of moderate degree in order to elucidate the functional plasticity of the auditory system. Sixteen right-handed, previously untreated adult patients with acute unilateral left (n = 8) or right (n = 8) ISSNHL of moderate degree were studied. Sixteen right-handed healthy volunteers with normal hearing served as control. Auditory neuromagnetic responses, measured by a whole-head 306-channel neuromagnetometer, were detected by monaural tone stimulation applied to affected and healthy ears, respectively, in different sessions. Intragroup and intergroup interhemispheric differences of peak dipole strengths and latencies of P50m and N100m, respectively, to monaural tones were evaluated. Healthy-side amplitude dominance of both P50m and N100m was found in ISSNHL, i.e. contralateral dominance was preserved on affected-ear stimulation but ipsilateral dominance was seen on healthy-ear stimulation. The phenomena could be attributed to the combined contralateral attenuation and ipsilateral enhancement of P50m and N100m activity in response to healthy-ear stimulation. Our findings confirmed that functional modulation can occur within the first few tens of milliseconds of evoked response at the auditory cortex in ISSNHL. The mechanisms of healthy-side dominance might be ascribed to a functional retune of auditory pathways, i.e. conjoined contralateral inhibition and ipsilateral excitation of the auditory pathway in response to healthy-ear stimulation. The effect could be registered in cortical responses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hata, Masaharu, E-mail: mhata@syd.odn.ne.jp; Omura, Motoko; Koike, Izumi

Purpose: Among extranodal lymphomas, orbital mucosa-associated lymphoid tissue (MALT) lymphoma is a relatively rare presentation. We performed a review to ascertain treatment efficacy and toxicity of radiation therapy for orbital MALT lymphoma. We also evaluated changes in visual acuity after irradiation. Methods and Materials: Thirty patients with orbital MALT lymphoma underwent radiation therapy with curative intent. Clinical stages at diagnosis were stage I{sub E}A in 29 patients and stage II{sub E}A in 1 patient. Total doses of 28.8 to 45.8 Gy (median, 30 Gy) in 15 to 26 fractions (median, 16 fractions) were delivered to the tumors. Results: All irradiatedmore » tumors were controlled during the follow-up period of 2 to 157 months (median, 35 months) after treatment. Two patients had relapses that arose in the cervical lymph node and the ipsilateral palpebral conjunctiva outside the radiation field at 15 and 67 months after treatment, respectively. The 5-year local progression-free and relapse-free rates were 100% and 96%, respectively. All 30 patients are presently alive; the overall and relapse-free survival rates at 5 years were 100% and 96%, respectively. Although 5 patients developed cataracts of grade 2 at 8 to 45 months after irradiation, they underwent intraocular lens implantation, and their eyesight recovered. Additionally, there was no marked deterioration in the visual acuity of patients due to irradiation, with the exception of cataracts. No therapy-related toxicity of grade 3 or greater was observed. Conclusions: Radiation therapy was effective and safe for patients with orbital MALT lymphoma. Although some patients developed cataracts after irradiation, visual acuity was well preserved.« less

A wire length minimization approach to ocular dominance patterns in mammalian visual cortex

NASA Astrophysics Data System (ADS)

Chklovskii, Dmitri B.; Koulakov, Alexei A.

2000-09-01

The primary visual area (V1) of the mammalian brain is a thin sheet of neurons. Because each neuron is dominated by either right or left eye one can treat V1 as a binary mixture of neurons. The spatial arrangement of neurons dominated by different eyes is known as the ocular dominance (OD) pattern. We propose a theory for OD patterns based on the premise that they are evolutionary adaptations to minimize the length of intra-cortical connections. Thus, the existing OD patterns are obtained by solving a wire length minimization problem. We divide all the neurons into two classes: right- and left-eye dominated. We find that if the number of connections of each neuron with the neurons of the same class differs from that with the other class, the segregation of neurons into monocular regions indeed reduces the wire length. The shape of the regions depends on the relative number of neurons in the two classes. If both classes are equally represented we find that the optimal OD pattern consists of alternating stripes. If one class is less numerous than the other, the optimal OD pattern consists of patches of the underrepresented (ipsilateral) eye dominated neurons surrounded by the neurons of the other class. We predict the transition from stripes to patches when the fraction of neurons dominated by the ipsilateral eye is about 40%. This prediction agrees with the data in macaque and Cebus monkeys. Our theory can be applied to other binary cortical systems.

Dorsolateral prefrontal cortex bridges bilateral primary somatosensory cortices during cross-modal working memory.

PubMed

Zhao, Di; Ku, Yixuan

2018-05-01

Neural activity in the dorsolateral prefrontal cortex (DLPFC) has been suggested to integrate information from distinct sensory areas. However, how the DLPFC interacts with the bilateral primary somatosensory cortices (SIs) in tactile-visual cross-modal working memory has not yet been established. In the present study, we applied single-pulse transcranial magnetic stimulation (sp-TMS) over the contralateral DLPFC and bilateral SIs of human participants at various time points, while they performed a tactile-visual delayed matching-to-sample task with a 2-second delay. sp-TMS over the contralateral DLPFC or the contralateral SI at either an sensory encoding stage [i.e. 100 ms after the onset of a vibrotactile sample stimulus (200-ms duration)] or an early maintenance stage (i.e. 300 ms after the onset), significantly impaired the accuracy of task performance; sp-TMS over the contralateral DLPFC or the ipsilateral SI at a late maintenance stage (1600 ms and 1900 ms) also significantly disrupted the performance. Furthermore, at 300 ms after the onset of the vibrotactile sample stimulus, there was a significant correlation between the deteriorating effects of sp-TMS over the contralateral SI and the contralateral DLPFC. These results imply that the DLPFC and the bilateral SIs play causal roles at distinctive stages during cross-modal working memory, while the contralateral DLPFC communicates with the contralateral SI in the early delay, and cooperates with the ipsilateral SI in the late delay. Copyright © 2018 Elsevier B.V. All rights reserved.

PARACENTRAL ACUTE MIDDLE MACULOPATHY ASSOCIATED WITH RETINAL ARTERY OCCLUSION AFTER COSMETIC FILLER INJECTION.

PubMed

Sridhar, Jayanth; Shahlaee, Abtin; Shieh, Wen-Shi; Rahimy, Ehsan

2017-01-01

To report a single case of paracentral acute middle maculopathy in association with retinal artery occlusion in the setting of ipsilateral facial cosmetic filler injection. Case report. A 35-year-old woman presenting with sudden vision loss to finger count vision immediately after left nasal fat pad cosmetic filler injection. Dilated funduscopic examination revealed a swollen optic disc with multiple branch arterial occlusions with visible embolic material. Fluorescein angiography confirmed multiple branch arterial occlusions in addition to a focal choroidal infarction in the macula. Spectral-domain optical coherence tomography revealed middle retinal hyperreflectivity in the superotemporal macula consistent with paracentral acute middle maculopathy. En face optical coherence tomography demonstrated a superotemporal area of whitening at the level of the deep capillary plexus corresponding to the paracentral acute middle maculopathy lesion seen on spectral-domain optical coherence tomography. On twelve-month follow-up, final visual acuity was 20/100 due to optic neuropathy. Emboli from cosmetic facial filler injections may rarely result in ipsilateral arterial occlusions and now have a novel association with paracentral acute middle maculopathy likely due to deep capillary plexus feeder vessel occlusion.

Feedforward compensation for novel dynamics depends on force field orientation but is similar for the left and right arms.

PubMed

Reuter, Eva-Maria; Cunnington, Ross; Mattingley, Jason B; Riek, Stephan; Carroll, Timothy J

2016-11-01

There are well-documented differences in the way that people typically perform identical motor tasks with their dominant and the nondominant arms. According to Yadav and Sainburg's (Neuroscience 196: 153-167, 2011) hybrid-control model, this is because the two arms rely to different degrees on impedance control versus predictive control processes. Here, we assessed whether differences in limb control mechanisms influence the rate of feedforward compensation to a novel dynamic environment. Seventy-five healthy, right-handed participants, divided into four subsamples depending on the arm (left, right) and direction of the force field (ipsilateral, contralateral), reached to central targets in velocity-dependent curl force fields. We assessed the rate at which participants developed predictive compensation for the force field using intermittent error-clamp trials and assessed both kinematic errors and initial aiming angles in the field trials. Participants who were exposed to fields that pushed the limb toward ipsilateral space reduced kinematic errors more slowly, built up less predictive field compensation, and relied more on strategic reaiming than those exposed to contralateral fields. However, there were no significant differences in predictive field compensation or kinematic errors between limbs, suggesting that participants using either the left or the right arm could adapt equally well to novel dynamics. It therefore appears that the distinct preferences in control mechanisms typically observed for the dominant and nondominant arms reflect a default mode that is based on habitual functional requirements rather than an absolute limit in capacity to access the controller specialized for the opposite limb. Copyright © 2016 the American Physiological Society.

Feedforward compensation for novel dynamics depends on force field orientation but is similar for the left and right arms

PubMed Central

Cunnington, Ross; Mattingley, Jason B.; Riek, Stephan; Carroll, Timothy J.

2016-01-01

There are well-documented differences in the way that people typically perform identical motor tasks with their dominant and the nondominant arms. According to Yadav and Sainburg's (Neuroscience 196: 153–167, 2011) hybrid-control model, this is because the two arms rely to different degrees on impedance control versus predictive control processes. Here, we assessed whether differences in limb control mechanisms influence the rate of feedforward compensation to a novel dynamic environment. Seventy-five healthy, right-handed participants, divided into four subsamples depending on the arm (left, right) and direction of the force field (ipsilateral, contralateral), reached to central targets in velocity-dependent curl force fields. We assessed the rate at which participants developed predictive compensation for the force field using intermittent error-clamp trials and assessed both kinematic errors and initial aiming angles in the field trials. Participants who were exposed to fields that pushed the limb toward ipsilateral space reduced kinematic errors more slowly, built up less predictive field compensation, and relied more on strategic reaiming than those exposed to contralateral fields. However, there were no significant differences in predictive field compensation or kinematic errors between limbs, suggesting that participants using either the left or the right arm could adapt equally well to novel dynamics. It therefore appears that the distinct preferences in control mechanisms typically observed for the dominant and nondominant arms reflect a default mode that is based on habitual functional requirements rather than an absolute limit in capacity to access the controller specialized for the opposite limb. PMID:27582293

Lateralized implicit sequence learning in uni- and bi-manual conditions.

PubMed

Schmitz, Rémy; Pasquali, Antoine; Cleeremans, Axel; Peigneux, Philippe

2013-02-01

It has been proposed that the right hemisphere (RH) is better suited to acquire novel material whereas the left hemisphere (LH) is more able to process well-routinized information. Here, we ask whether this potential dissociation also manifests itself in an implicit learning task. Using a lateralized version of the serial reaction time task (SRT), we tested whether participants trained in a divided visual field condition primarily stimulating the RH would learn the implicit regularities embedded in sequential material faster than participants in a condition favoring LH processing. In the first study, half of participants were presented sequences in the left (vs. right) visual field, and had to respond using their ipsilateral hand (unimanual condition), hence making visuo-motor processing possible within the same hemisphere. Results showed successful implicit sequence learning, as indicated by increased reaction time for a transfer sequence in both hemispheric conditions and lack of conscious knowledge in a generation task. There was, however, no evidence of interhemispheric differences. In the second study, we hypothesized that a bimanual response version of the lateralized SRT, which requires interhemispheric communication and increases computational and cognitive processing loads, would favor RH-dependent visuospatial/attentional processes. In this bimanual condition, our results revealed a much higher transfer effect in the RH than in the LH condition, suggesting higher RH sensitivity to the processing of novel sequential material. This LH/RH difference was interpreted within the framework of the Novelty-Routinization model [Goldberg, E., & Costa, L. D. (1981). Hemisphere differences in the acquisition and use of descriptive systems. Brain and Language, 14(1), 144-173] and interhemispheric interactions in attentional processing [Banich, M. T. (1998). The missing link: the role of interhemispheric interaction in attentional processing. Brain and Cognition, 36(2), 128-157]. Copyright © 2012 Elsevier Inc. All rights reserved.

Frontal Non-Invasive Neurostimulation Modulates Antisaccade Preparation in Non-Human Primates

PubMed Central

Valero-Cabre, Antoni; Wattiez, Nicolas; Monfort, Morgane; François, Chantal; Rivaud-Péchoux, Sophie; Gaymard, Bertrand; Pouget, Pierre

2012-01-01

A combination of oculometric measurements, invasive electrophysiological recordings and microstimulation have proven instrumental to study the role of the Frontal Eye Field (FEF) in saccadic activity. We hereby gauged the ability of a non-invasive neurostimulation technology, Transcranial Magnetic Stimulation (TMS), to causally interfere with frontal activity in two macaque rhesus monkeys trained to perform a saccadic antisaccade task. We show that online single pulse TMS significantly modulated antisaccade latencies. Such effects proved dependent on TMS site (effects on FEF but not on an actively stimulated control site), TMS modality (present under active but not sham TMS on the FEF area), TMS intensity (intensities of at least 40% of the TMS machine maximal output required), TMS timing (more robust for pulses delivered at 150 ms than at 100 post target onset) and visual hemifield (relative latency decreases mainly for ipsilateral AS). Our results demonstrate the feasibility of using TMS to causally modulate antisaccade-associated computations in the non-human primate brain and support the use of this approach in monkeys to study brain function and its non-invasive neuromodulation for exploratory and therapeutic purposes. PMID:22701691

A method for determination of equine hoof strain patterns using photoelasticity: an in vitro study.

PubMed

Dejardin, L M; Arnoczky, S P; Cloud, G L

1999-05-01

During impact, equine hooves undergo viscoelastic deformations which may result in potentially harmful strains. Previous hoof strain studies using strain gauges have been inconclusive due to arbitrary gauge placement. Photoelastic stress analysis (PSA) is a full-field technique which visually displays strains over entire loaded surfaces. This in vitro study identifies normal hoof strain patterns using PSA. Custom-made photoelastic plastic sheets were applied to the hoof surface. The hooves were axially loaded (225 kg) under level and varus/valgus conditions. Strain patterns were video-recorded through a polariscope. Strains were concentrated between middle and distal thirds of the hoof wall regardless of the loading conditions. This strain distribution appears to result from the differential expansion of the hoof wall under load. Increasing load resulted in higher strains and asymmetric loading resulted in an ipsilateral increase in strain magnitudes without altering strain locations. This study shows that PSA is a reliable method with which to evaluate hoof strains in vitro and is sensitive enough to reflect subtle load-related strain alterations.

Choosing the appropriate side for subcutaneous port catheter placement in patients with mastectomy: ipsilateral or contralateral?

PubMed

Nas, Omer Fatih; Hacikurt, Kadir; Kaya, Ahmet; Dogan, Nurullah; Sanal, Bekir; Ozkaya, Guven; Dundar, Halit Ziya; Erdogan, Cuneyt

2017-06-01

To evaluate long-term clinical follow-up results of implanting subcutaneous port catheters (SPCs) on ipsilateral or contralateral with mastectomy side in patients with axillary lymph node dissection. A total of 73 patients composed of ipsilateral (34 catheters) and contralateral (39 catheters) groups, with SPCs were included. All patients had lumpectomy or modified radical mastectomy for breast cancer. Ipsilateral and contralateral groups had similar patient characteristics. Five late complications were seen in the ipsilateral group and 2 late complications in the contralateral group. No statistical significant difference was seen between two groups in regard to late complications. Four complications of the ipsilateral group were classified as major group C and 1 as major group D, while 1 complication of the contralateral group was classified as minor group B and 1 as major group C according to Society of Interventional Radiology (SIR) classification. No statistical significant difference was seen between complication rates of two groups in regard to SIR classification. SPC related complications do not differ in regard to ipsilateral or contralateral side selection on mastectomized patients with breast cancer and lymph node dissection. SPCs can be implanted on ipsilateral or contralateral sides of the operation in these patients.

The identification of conduction gaps after pulmonary vein isolation using a new electroanatomic mapping system.

PubMed

Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Matsuda, Yasuhiro; Okuno, Shota; Ohashi, Takuya; Tsuji, Aki; Mano, Toshiaki

2017-11-01

The reconnection of left atrial-pulmonary vein (LA-PV) conduction after the initial procedure of pulmonary vein (PV) isolation is not rare, and is one of the main cause of atrial fibrillation (AF) recurrence after PV isolation. We investigated feasibility of a new ultrahigh-resolution mapping system using a 64-pole small basket catheter for the identification of LA-PV conduction gaps. This prospective study included 31 consecutive patients (20 with persistent AF) undergoing a second ablation after a PV isolation procedure with LA-PV reconnected conduction at any of the 4 PVs. An LA-PV map was created using the mapping system, and ablation was performed at the estimated gap location. The propagation map identified 54 gaps from 39 ipsilateral PV pairs, requiring manual electrogram reannotation for 23 gaps (43%). Gaps at the anterior and carinal regions of left and right ipsilateral PVs required manual electrogram reannotation more frequently than the other regions. The voltage map could identify the gap only in 19 instances (35%). Electrophysiological properties of the gaps (multiple gaps in the same ipsilateral PVs, conduction time, velocity, width, and length) did not differ between those needing and not needing manual electrogram reannotation. During the gap ablation, either the activation sequence alteration or elimination of PV potentials was observed using a circular catheter placed in the PV, suggesting that all the identified gaps were correct. This new electroanatomic mapping system visualized all the LA-PV gaps in patients undergoing a second AF ablation. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

The Mirror Illusion Increases Motor Cortex Excitability in Children With and Without Hemiparesis.

PubMed

Grunt, Sebastian; Newman, Christopher J; Saxer, Stefanie; Steinlin, Maja; Weisstanner, Christian; Kaelin-Lang, Alain

2017-03-01

Mirror therapy provides a visual illusion of a normal moving limb by using the mirror reflection of the unaffected arm instead of viewing the paretic limb and is used in rehabilitation to improve hand function. Little is known about the mechanism underlying its effect in children with hemiparesis. To investigate the effect of the mirror illusion (MI) on the excitability of the primary motor cortex (M1) in children and adolescents. Twelve patients with hemiparesis (10-20 years) and 8 typically developing subjects (8-17 years) participated. Corticospinal reorganization was classified as contralateral (projection from contralateral hemisphere to affected hand) or ipsilateral (projection from ipsilateral hemisphere to affected hand). M1 excitability of the hemisphere projecting to the affected (nondominant in typically developing subjects) hand was obtained during 2 different conditions using single-pulse transcranial magnetic stimulation (TMS). Each condition (without/with mirror) consisted of a unimanual and a bimanual task. Motor-evoked potentials (MEPs) were recorded from the abductor pollicis brevis and flexor digitorum superficialis muscles. MEP amplitudes were significantly increased during the mirror condition ( P = .005) in typically developing subjects and in patients with contralateral reorganization. No significant effect of MI was found in subjects with ipsilateral reorganization. MI increased M1 excitability during active movements only. This increase was not correlated to hand function. MI increases the excitability of M1 in hemiparetic patients with contralateral corticospinal organization and in typically developing subjects. This finding provides neurophysiological evidence supporting the application of mirror therapy in selected children and adolescents with hemiparesis.

Involvement of α2-adrenoceptors in inhibitory and facilitatory pain modulation processes.

PubMed

Vo, L; Drummond, P D

2016-03-01

In healthy humans, high-frequency electrical stimulation (HFS) of the forearm not only produces hyperalgesia at the site of stimulation but also reduces sensitivity to pressure-pain on the ipsilateral side of the forehead. In addition, HFS augments the ipsilateral trigeminal nociceptive blink reflex and intensifies the ipsilateral component of conditioned pain modulation. The aim of this study was to determine whether α2-adrenoceptors mediate these ipsilateral nociceptive influences. The α2-adrenoceptor antagonist yohimbine was administered to 22 participants in a double-blind, placebo-controlled crossover study. In each session, thermal and mechanical sensitivity in the forearms and forehead was assessed before and after HFS. In addition, the combined effect of HFS and yohimbine on the nociceptive blink reflex and on conditioned pain modulation was explored. In this paradigm, the conditioning stimulus was cold pain in the ipsilateral or contralateral temple, and the test stimulus was electrically evoked pain in the forearm. Blood pressure and electrodermal activity increased for several hours after yohimbine administration, consistent with blockade of central α2-adrenoceptors. Yohimbine not only augmented the nociceptive blink reflex ipsilateral to HFS but also intensified the inhibitory influence of ipsilateral temple cooling on electrically evoked pain at the HFS-treated site in the forearm. Yohimbine had no consistent effect on primary or secondary hyperalgesia in the forearm or on pressure-pain in the ipsilateral forehead. These findings imply involvement of α2-adrenoceptors both in ipsilateral antinociceptive and pronociceptive pain modulation processes. However, a mechanism not involving α2-adrenoceptors appears to mediate analgesia in the ipsilateral forehead after HFS. © 2015 European Pain Federation - EFIC®

Discharge properties of Purkinje cells in the oculomotor vermis during visually guided saccades in the macaque monkey.

PubMed

Ohtsuka, K; Noda, H

1995-11-01

1. We previously described discharge properties of cerebellar output cells in the fastigial nucleus during ipsilateral and contralateral saccades. Fastigial cells exhibited unique responses depending on the direction of saccades and were involved in execution of accurate targeting saccades. Purkinje cells in the oculomotor vermis (lobules VIc and VII) are thought to modulate these discharges of fastigial cells. In this study we reexamine discharge properties of Purkinje cells on the basis of this hypothesis. 2. Initially we physiologically identified the right and left sides of the oculomotor vermis. Saccade-related discharges of 79 Purkinje cells were recorded from both sides of the vermis during visually guided saccades toward the sides ipsilateral and contralateral to the recording side in two trained macaque monkeys. To clarify the correlation of Purkinje cell discharge with burst activities in the fastigial nucleus during saccadic eye movements, we analyzed our data by employing methods used in the study of fastigial neurons. 3. Among the 79 cells, 56 (71%) showed burst discharges during saccades (saccadic burst cells). Of the 56 cells, 29 exhibited a peak of burst discharges in both the contralateral and ipsilateral directions (bidirectional cells). The remaining 27 saccadic burst cells showed a peak of burst discharges during either contralateral or ipsilateral saccades (unidirectional cells). Among the 79 cells, 14 (18%) exhibited a pause of discharges during contralateral saccades (pause cells). Among the 79 cells, 9 (11%) showed burst discharge during contralateral saccades followed by tonic discharge that was correlated with eye position (burst tonic cells). 4. The timing of bursts in bidirectional cells with respect to saccade onset was dependent on the direction of saccade. During ipsilateral saccades, Purkinje cells exhibited a long lead burst that built up gradually, peaked near the onset of the saccade, and terminated sharply near midsaccade. The mean lead time relative to saccade onset was 29.3 +/- 24.5 (SD) ms. During contralateral saccades, Purkinje cells exhibited a short lead/late burst that built up sharply, peaked near midsaccade, and terminated gradually after the end of the saccade. The mean lead time relative to saccade onset was 10.7 +/- 20.8 ms. The burst onset time during contralateral saccades and the burst offset time during ipsilateral saccades preceded the saccade offset time by about the same interval regardless of the saccade amplitude. 5. In pause cells the pause preceded saccade onset by 17.5 +/- 10.6 ms. The duration of the pause was not correlated with the duration of saccades. There was little trial-to-trial variability in the onset time of the pause with respect to the onset of saccades, whereas there was large trial-to-trial variability in the offset time of the pause with respect to the offset of saccades. In addition, the mean onset time of the pause for each cell had a relatively narrow distribution. 6. The burst lead time of burst tonic cells relative to saccade onset was 9.5 +/- 3.9 ms. The tonic discharge rate of burst tonic cells was a nonlinear function of eye position. The regression of each cell was fit to two lines. The regression coefficient ranged from 0.95 to 0.99 (mean = 0.97). 7. Axons of Purkinje cells in the oculomotor vermis are thought to project exclusively to saccadic burst cells in the fastigial oculomotor region (FOR), which is located in the caudal portion of the fastigial nucleus. Our previous studies indicated that FOR cells provide temporal signals for controlling targeting saccades. The present results suggest that Purkinje cells in the oculomotor vermis modify the temporal signals of FOR cells for saccades in different directions and amplitudes. The modification of FOR cell activity by Purkinje cells is thought to be essential for the function of the cerebellum in the control of saccadic eye movements.

Ipsilateral hemiparesis in ischemic stroke patients.

PubMed

Inatomi, Y; Nakajima, M; Yonehara, T; Ando, Y

2017-07-01

To investigate clinical characteristics of ipsilateral hemiparesis in ischemic stroke patients. Patients with acute ischemic stroke were prospectively examined. Ipsilateral hemiparesis was defined as hemiparesis ipsilateral to recent stroke lesions. Patients with ipsilateral hemiparesis were examined with functional neuroimaging studies including transcranial magnetic stimulation (TMS) and functional MRI. Of 8360 patients, ipsilateral hemiparesis was detected in 14 patients (0.17%, mean age 71±6 years, eight men). Lesions responsible for the recent strokes were located in the frontal cortex in three patients, corona radiata in seven, internal capsule in one, and pons in three. These lesions were located along the typical route of the corticospinal tract in all but one patient. Thirteen patients also had a past history of stroke contralateral to the recent lesions; 12 of these had motor deficits contralateral to past stroke lesions. During TMS, ipsilateral magnetic evoked potentials were evoked in two of seven patients and contralateral potentials were evoked in all seven. Functional MRI activated cerebral hemispheres ipsilaterally in eight of nine patients and contralaterally in all nine. Most patients with ipsilateral hemiparesis had a past history of stroke contralateral to the recent one, resulting in motor deficits contralateral to the earlier lesions. Moreover, functional neuroimaging findings indicated an active crossed corticospinal tract in all of the examined patients. Both findings suggest the contribution of the uncrossed corticospinal tract contralateral to stroke lesions as a post-stroke compensatory motor system. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Hemispheric Asymmetry of Visual Cortical Response by Means of Functional Transcranial Doppler

PubMed Central

Roje-Bedeković, Marina; Lovrenčić-Huzjan, Arijana; Bosnar-Puretić, Marijana; Šerić, Vesna; Demarin, Vida

2012-01-01

We assessed the visual evoked response and investigated side-to-side differences in mean blood flow velocities (MBFVs) by means of functional transcranial Doppler (fTCD) in 49 right-handed patients with severe internal carotid artery (ICA) stenosis and 30 healthy volunteers, simultaneously in both posterior cerebral arteries (PCAs) using 2 MHz probes, successively in the dark and during the white light stimulation. Statistically significant correlation (P = 0.001) was shown in healthy and in patients (P < 0.05) between MBFV in right PCA in physiological conditions and MBFV in right PCA during the white light stimulation and in the dark. The correlation between MBVF in right PCA and contralateral left PCA was not statistically significant (P > 0.05). The correlation between ipsilateral left PCA was significantly higher than the one with contralateral right PCA (P < 0.05). There is a clear trend towards the lateralisation of the visual evoked response in the right PCA. PMID:22135771

Cortical Effects on Ipsilateral Hindlimb Muscles Revealed with Stimulus-Triggered Averaging of EMG Activity

PubMed Central

Messamore, William G.; Van Acker, Gustaf M.; Hudson, Heather M.; Zhang, Hongyu Y.; Kovac, Anthony; Nazzaro, Jules; Cheney, Paul D.

2016-01-01

While a large body of evidence supports the view that ipsilateral motor cortex may make an important contribution to normal movements and to recovery of function following cortical injury (Chollet et al. 1991; Fisher 1992; Caramia et al. 2000; Feydy et al. 2002), relatively little is known about the properties of output from motor cortex to ipsilateral muscles. Our aim in this study was to characterize the organization of output effects on hindlimb muscles from ipsilateral motor cortex using stimulus-triggered averaging of EMG activity. Stimulus-triggered averages of EMG activity were computed from microstimuli applied at 60–120 μA to sites in both contralateral and ipsilateral M1 of macaque monkeys during the performance of a hindlimb push–pull task. Although the poststimulus effects (PStEs) from ipsilateral M1 were fewer in number and substantially weaker, clear and consistent effects were obtained at an intensity of 120 μA. The mean onset latency of ipsilateral poststimulus facilitation was longer than contralateral effects by an average of 0.7 ms. However, the shortest latency effects in ipsilateral muscles were as short as the shortest latency effects in the corresponding contralateral muscles suggesting a minimal synaptic linkage that is equally direct in both cases. PMID:26088970

Neurovascular Study of the Trigeminal Nerve at 3 T MRI

PubMed Central

Gonzalez, Nadia; Muñoz, Alexandra; Bravo, Fernando; Sarroca, Daniel; Morales, Carlos

2015-01-01

This study aimed to show a novel visualization method to investigate neurovascular compression of the trigeminal nerve (TN) using a volume-rendering fusion imaging technique of 3D fast imaging employing steady-state acquisition (3D FIESTA) and coregistered 3D time of flight MR angiography (3D TOF MRA) sequences, which we called “neurovascular study of the trigeminal nerve”. We prospectively studied 30 patients with unilateral trigeminal neuralgia (TN) and 50 subjects without symptoms of TN (control group), on a 3 Tesla scanner. All patients were assessed using 3D FIESTA and 3D TOF MRA sequences centered on the pons, as well as a standard brain protocol including axial T1, T2, FLAIR and GRE sequences to exclude other pathologies that could cause TN. Post-contrast T1-weighted sequences were also performed. All cases showing arterial imprinting on the trigeminal nerve (n = 11) were identified on the ipsilateral side of the pain. No significant relationship was found between the presence of an artery in contact with the trigeminal nerve and TN. Eight cases were found showing arterial contact on the ipsilateral side of the pain and five cases of arterial contact on the contralateral side. The fusion imaging technique of 3D FIESTA and 3D TOF MRA sequences, combining the high anatomical detail provided by the 3D FIESTA sequence with the 3D TOF MRA sequence and its capacity to depict arterial structures, results in a tool that enables quick and efficient visualization and assessment of the relationship between the trigeminal nerve and the neighboring vascular structures. PMID:25924169

Bilateral Activity-Dependent Interactions in the Developing Corticospinal System

PubMed Central

Friel, Kathleen M.; Martin, John H.

2009-01-01

Activity-dependent competition between the corticospinal (CS) systems in each hemisphere drives postnatal development of motor skills and stable CS tract connections with contralateral spinal motor circuits. Unilateral restriction of motor cortex (M1) activity during an early postnatal critical period impairs contralateral visually guided movements later in development and in maturity. Silenced M1 develops aberrant connections with the contralateral spinal cord whereas the initially active M1, in the other hemisphere, develops bilateral connections. In this study, we determined whether the aberrant pattern of CS tract terminations and motor impairments produced by early postnatal M1 activity restriction could be abrogated by reducing activity-dependent synaptic competition from the initially active M1 later in development. We first inactivated M1 unilaterally between postnatal weeks 5–7. We next inactivated M1 on the other side from weeks 7–11 (alternate inactivation), to reduce the competitive advantage that this side may have over the initially inactivated side. Alternate inactivation redirected aberrant contralateral CS tract terminations from the initially silenced M1 to their normal spinal territories and reduced the density of aberrant ipsilateral terminations from the initially active side. Normal movement endpoint control during visually guided locomotion was fully restored. This reorganization of CS terminals reveals an unsuspected late plasticity after the critical period for establishing the pattern of CS terminations in the spinal cord. Our findings show that robust bilateral interactions between the developing CS systems on each side are important for achieving balance between contralateral and ipsilateral CS tract connections and visuomotor control. PMID:17928450

Neuronal network-based mathematical modeling of perceived verticality in acute unilateral vestibular lesions: from nerve to thalamus and cortex.

PubMed

Glasauer, S; Dieterich, M; Brandt, T

2018-05-29

Acute unilateral lesions of vestibular graviceptive pathways from the otolith organs and semicircular canals via vestibular nuclei and the thalamus to the parieto-insular vestibular cortex regularly cause deviations of perceived verticality in the frontal roll plane. These tilts are ipsilateral in peripheral and in ponto-medullary lesions and contralateral in ponto-mesencephalic lesions. Unilateral lesions of the vestibular thalamus or cortex cause smaller tilts of the perceived vertical, which may be either ipsilateral or contralateral. Using a neural network model, we previously explained why unilateral vestibular midbrain lesions rarely manifest with rotational vertigo. We here extend this approach, focussing on the direction-specific deviations of perceived verticality in the roll plane caused by acute unilateral vestibular lesions from the labyrinth to the cortex. Traditionally, the effect of unilateral peripheral lesions on perceived verticality has been attributed to a lesion-based bias of the otolith system. We here suggest, on the basis of a comparison of model simulations with patient data, that perceived visual tilt after peripheral lesions is caused by the effect of a torsional semicircular canal bias on the central gravity estimator. We further argue that the change of gravity coding from a peripheral/brainstem vectorial representation in otolith coordinates to a distributed population coding at thalamic and cortical levels can explain why unilateral thalamic and cortical lesions have a variable effect on perceived verticality. Finally, we propose how the population-coding network for gravity direction might implement the elements required for the well-known perceptual underestimation of the subjective visual vertical in tilted body positions.

Genetic visualization with an improved GCaMP calcium indicator reveals spatiotemporal activation of the spinal motor neurons in zebrafish

PubMed Central

Muto, Akira; Ohkura, Masamichi; Kotani, Tomoya; Higashijima, Shin-ichi; Nakai, Junichi; Kawakami, Koichi

2011-01-01

Animal behaviors are generated by well-coordinated activation of neural circuits. In zebrafish, embryos start to show spontaneous muscle contractions at 17 to 19 h postfertilization. To visualize how motor circuits in the spinal cord are activated during this behavior, we developed GCaMP-HS (GCaMP-hyper sensitive), an improved version of the genetically encoded calcium indicator GCaMP, and created transgenic zebrafish carrying the GCaMP-HS gene downstream of the Gal4-recognition sequence, UAS (upstream activation sequence). Then we performed a gene-trap screen and identified the SAIGFF213A transgenic fish that expressed Gal4FF, a modified version of Gal4, in a subset of spinal neurons including the caudal primary (CaP) motor neurons. We conducted calcium imaging using the SAIGFF213A; UAS:GCaMP-HS double transgenic embryos during the spontaneous contractions. We demonstrated periodic and synchronized activation of a set of ipsilateral motor neurons located on the right and left trunk in accordance with actual muscle movements. The synchronized activation of contralateral motor neurons occurred alternately with a regular interval. Furthermore, a detailed analysis revealed rostral-to-caudal propagation of activation of the ipsilateral motor neuron, which is similar to but much slower than the rostrocaudal delay observed during swimming in later stages. Our study thus demonstrated coordinated activities of the motor neurons during the first behavior in a vertebrate. We propose the GCaMP technology combined with the Gal4FF-UAS system is a powerful tool to study functional neural circuits in zebrafish. PMID:21383146

Linking pain and the body: neural correlates of visually induced analgesia.

PubMed

Longo, Matthew R; Iannetti, Gian Domenico; Mancini, Flavia; Driver, Jon; Haggard, Patrick

2012-02-22

The visual context of seeing the body can reduce the experience of acute pain, producing a multisensory analgesia. Here we investigated the neural correlates of this "visually induced analgesia" using fMRI. We induced acute pain with an infrared laser while human participants looked either at their stimulated right hand or at another object. Behavioral results confirmed the expected analgesic effect of seeing the body, while fMRI results revealed an associated reduction of laser-induced activity in ipsilateral primary somatosensory cortex (SI) and contralateral operculoinsular cortex during the visual context of seeing the body. We further identified two known cortical networks activated by sensory stimulation: (1) a set of brain areas consistently activated by painful stimuli (the so-called "pain matrix"), and (2) an extensive set of posterior brain areas activated by the visual perception of the body ("visual body network"). Connectivity analyses via psychophysiological interactions revealed that the visual context of seeing the body increased effective connectivity (i.e., functional coupling) between posterior parietal nodes of the visual body network and the purported pain matrix. Increased connectivity with these posterior parietal nodes was seen for several pain-related regions, including somatosensory area SII, anterior and posterior insula, and anterior cingulate cortex. These findings suggest that visually induced analgesia does not involve an overall reduction of the cortical response elicited by laser stimulation, but is consequent to the interplay between the brain's pain network and a posterior network for body perception, resulting in modulation of the experience of pain.

Unique cortical physiology associated with ipsilateral hand movements and neuroprosthetic implications.

PubMed

Wisneski, Kimberly J; Anderson, Nicholas; Schalk, Gerwin; Smyth, Matt; Moran, Daniel; Leuthardt, Eric C

2008-12-01

Brain computer interfaces (BCIs) offer little direct benefit to patients with hemispheric stroke because current platforms rely on signals derived from the contralateral motor cortex (the same region injured by the stroke). For BCIs to assist hemiparetic patients, the implant must use unaffected cortex ipsilateral to the affected limb. This requires the identification of distinct electrophysiological features from the motor cortex associated with ipsilateral hand movements. In this study we studied 6 patients undergoing temporary placement of intracranial electrode arrays. Electrocorticographic (ECoG) signals were recorded while the subjects engaged in specific ipsilateral or contralateral hand motor tasks. Spectral changes were identified with regards to frequency, location, and timing. Ipsilateral hand movements were associated with electrophysiological changes that occur in lower frequency spectra, at distinct anatomic locations, and earlier than changes associated with contralateral hand movements. In a subset of 3 patients, features specific to ipsilateral and contralateral hand movements were used to control a cursor on a screen in real time. In ipsilateral derived control this was optimal with lower frequency spectra. There are distinctive cortical electrophysiological features associated with ipsilateral movements which can be used for device control. These findings have implications for patients with hemispheric stroke because they offer a potential methodology for which a single hemisphere can be used to enhance the function of a stroke induced hemiparesis.

Unilateral optic nerve transection alters light response of suprachiasmatic nucleus and intergeniculate leaflet

NASA Technical Reports Server (NTRS)

Tang, I-Hsiung; Murakami, Dean M.; Fuller, Charles A.

2002-01-01

The suprachiasmatic nucleus (SCN), the circadian pacemaker, receives photic input directly from the retina to synchronize the pacemaker to the environment. Additionally, the intergeniculate leaflet (IGL), which innervates the SCN, is known to modulate the retinal photic input to the SCN. To further understand the role of the IGL in mediating the photic input to the SCN, this study examined the effects of unilateral optic nerve transection (UONx) on the photic response of the SCN and IGL in adult and neonatal hamsters. UONx led to an overall reduction in light-induced c-Fos expression in the SCN and IGL. The c-Fos expression was greater in the SCN ipsilateral to the remaining eye, despite a symmetrically bilateral retinohypothalamic tract projection as revealed by intraocular injection of horseradish peroxidase. In contrast, UONx led to a greater c-Fos expression in the contralateral IGL. The contralateral IGL of UONx animals also revealed more neuropeptide Y-immunoreactive neurons, while the ipsilateral SCN of these animals exhibited a denser neuropeptide Y terminal field. The neonates with UONx showed a similar pattern with a slight compensation of the photic-induced c-Fos in the SCN. This study suggests that the IGL may have an ipsilateral inhibitory effect in mediating retinal photic input to the SCN.

Efferent projections of the dorsal ventricular ridge and the striatum in the Tegu lizard. Tupinambis nigropunctatus.

PubMed

Voneida, T J; Sligar, C M

1979-07-01

A H3 proline-leucine mixture was injected into the dorsal ventricular ridge (DVR) and striatum of the Tegu lizard in order to determine their efferent projections. The brains were processed according to standard radioautographic technique, and counterstained with cresyl violet. DVR projections were generally restricted to the telencephalon, while striatal projections were limited to diencephalic and mesencephalic structures. Thus the anterior DVR projects ipsilaterally to nuclei sphericus and lateralis amygdalae, striatum (ipsilateral and contralateral) ventromedial nucleus of the hypothalamus, nucleus accumbens, anterior olfactory nucleus, nucleus of the lateral olfactory tract and lateral pallium. Posterior DVR projections enter ipsilateral anterior olfactory nucleus, lateral and interstitial amygdalar nuclei, olfactory tubercle and bulb, nucleus of the lateral olfactory tract and a zone surrounding the ventromedial hypothalamic nucleus. Labeled axons from striatal injections pass caudally in the lateral forebrain bundle to enter (via dorsal peduncle) nuclei dorsomedialis, medialis posterior, entopeduncularis anterior, and a zone surrounding nucleus rotundus. Others join the ventral peduncle of LFB and enter ventromedial nucleus (thalami), while the remaining fibers continue caudally in the ventral peduncle to the mesencephalic prerubral field, central gray, substantia nigra, nucleus intercollicularis, reticular formation and pretectal nucleus posterodorsalis. These results are discussed in relation to the changing notions regarding terminology, classification and functions of dorsl ventricular ridge and striatum.

Corticospinal activation of internal oblique muscles has a strong ipsilateral component and can be lateralised in man.

PubMed

Strutton, Paul H; Beith, Iain D; Theodorou, Sophie; Catley, Maria; McGregor, Alison H; Davey, Nick J

2004-10-01

Trunk muscles receive corticospinal innervation ipsilaterally and contralaterally and here we investigate the degree of ipsilateral innervation and any cortical asymmetry in pairs of trunk muscles and proximal and distal limb muscles. Transcranial magnetic stimulation (TMS) was applied to left and right motor cortices in turn and bilateral electromyographic (EMG) recordings were made from internal oblique (IO; lower abdominal), deltoid (D; shoulder) and first dorsal interosseus (1DI; hand) muscles during voluntary contraction in ten healthy subjects. We used a 7-cm figure-of-eight stimulating coil located 2 cm lateral and 2 cm anterior to the vertex over either cortex. Incidence of ipsilateral motor evoked potentials (MEPs) was 85% in IO, 40% in D and 35% in 1DI. Mean (+/- S.E.M.) ipsilateral MEP latencies were longer ( P<0.05; paired t-test) than contralateral MEP latencies (contralateral vs. ipsilateral; IO: 16.1+/-0.4 ms vs. 19.0+/-0.5 ms; D: 9.7+/-0.3 ms vs. 15.1+/-1.9 ms; 1DI: 18.3+/-0.6 ms vs. 23.3+/-1.4 ms), suggesting that ipsilateral MEPs were not a result of interhemispheric current spread. Where data were available, we calculated a ratio (ipsilateral MEP areas/contralateral MEP areas) for a given muscle (IO: n=16; D: n=8; 1DI: n=7 ratios). Mean values for these ratios were 0.70+/-0.20 (IO), 0.14+/-0.05 (D) and 0.08+/-0.02 (1DI), revealing stronger ipsilateral drive to IO. Comparisons of the sizes of these ratios revealed a bias towards one cortex or the other (four subjects right; three subjects left). The predominant cortex showed a mean ratio of 1.21+/-0.38 compared with 0.26+/-0.06 in the other cortex ( P<0.05). It appears that the corticospinal control of IO has a strong ipsilateral component relative to the limb muscles and also shows hemispheric asymmetry.

Volumetric tumor burden and its effect on brachial plexus dosimetry in head and neck intensity-modulated radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romesser, Paul B.; Qureshi, Muhammad M.; Kovalchuk, Nataliya

2014-07-01

To determine the effect of gross tumor volume of the primary (GTV-P) and nodal (GTV-N) disease on planned radiation dose to the brachial plexus (BP) in head and neck intensity-modulated radiotherapy (IMRT). Overall, 75 patients underwent definitive IMRT to a median total dose of 69.96 Gy in 33 fractions. The right BP and left BP were prospectively contoured as separate organs at risk. The GTV was related to BP dose using the unpaired t-test. Receiver operating characteristics curves were constructed to determine optimized volumetric thresholds of GTV-P and GTV-N corresponding to a maximum BP dose cutoff of > 66 Gy.more » Multivariate analyses were performed to account for factors associated with a higher maximal BP dose. A higher maximum BP dose (> 66 vs ≤ 66 Gy) correlated with a greater mean GTV-P (79.5 vs 30.8 cc; p = 0.001) and ipsilateral GTV-N (60.6 vs 19.8 cc; p = 0.014). When dichotomized by the optimized nodal volume, patients with an ipsilateral GTV-N ≥ 4.9 vs < 4.9 cc had a significant difference in maximum BP dose (64.2 vs 59.4 Gy; p = 0.001). Multivariate analysis confirmed that an ipsilateral GTV-N ≥ 4.9 cc was an independent predictor for the BP to receive a maximal dose of > 66 Gy when adjusted individually for BP volume, GTV-P, the use of a low anterior neck field technique, total planned radiation dose, and tumor category. Although both the primary and the nodal tumor volumes affected the BP maximal dose, the ipsilateral nodal tumor volume (GTV-N ≥ 4.9 cc) was an independent predictor for high maximal BP dose constraints in head and neck IMRT.« less

Gait asymmetries in unilateral symptomatic hip osteoarthritis and their association with radiographic severity and pain.

PubMed

Farkas, Gary J; Schlink, Bryan R; Fogg, Louis F; Foucher, Kharma C; Wimmer, Markus A; Shakoor, Najia

2018-05-01

Little is known about the loading patterns in unilateral hip osteoarthritis (OA) and their relationship to radiographic severity and pain. We aimed to examine the loading patterns at the hips of those with unilateral symptomatic hip OA and identify associations between radiographic severity and pain with loading alterations. Sixty-one subjects with symptomatic unilateral hip OA underwent gait analyses and evaluation for radiographic severity (Kellgren-Lawrence [KL]-grade) and pain (visual analogue scale) at bilateral hips. Hip OA subjects had greater range of motion and higher hip flexion, adduction, internal and external rotation moments at the contralateral, asymptomatic hip compared to the ipsilateral hip ( p < 0.05). Correlations were noted between increasing KL-grade and increasing asymmetry of contralateral to ipsilateral hip loading ( p < 0.05). There were no relationships with pain and loading asymmetry. Unilateral symptomatic hip OA subjects demonstrate asymmetry in loading between the hips, with relatively greater loads at the contralateral hip. These loading asymmetries were directly related to the radiographic severity of symptomatic hip OA and not with pain. Additional research is needed to determine the role of gait asymmetries in disease progression.

Global signal modulation of single-trial fMRI response variability: Effect on positive vs negative BOLD response relationship.

PubMed

Mayhew, S D; Mullinger, K J; Ostwald, D; Porcaro, C; Bowtell, R; Bagshaw, A P; Francis, S T

2016-06-01

In functional magnetic resonance imaging (fMRI), the relationship between positive BOLD responses (PBRs) and negative BOLD responses (NBRs) to stimulation is potentially informative about the balance of excitatory and inhibitory brain responses in sensory cortex. In this study, we performed three separate experiments delivering visual, motor or somatosensory stimulation unilaterally, to one side of the sensory field, to induce PBR and NBR in opposite brain hemispheres. We then assessed the relationship between the evoked amplitudes of contralateral PBR and ipsilateral NBR at the level of both single-trial and average responses. We measure single-trial PBR and NBR peak amplitudes from individual time-courses, and show that they were positively correlated in all experiments. In contrast, in the average response across trials the absolute magnitudes of both PBR and NBR increased with increasing stimulus intensity, resulting in a negative correlation between mean response amplitudes. Subsequent analysis showed that the amplitude of single-trial PBR was positively correlated with the BOLD response across all grey-matter voxels and was not specifically related to the ipsilateral sensory cortical response. We demonstrate that the global component of this single-trial response modulation could be fully explained by voxel-wise vascular reactivity, the BOLD signal standard deviation measured in a separate resting-state scan (resting state fluctuation amplitude, RSFA). However, bilateral positive correlation between PBR and NBR regions remained. We further report that modulations in the global brain fMRI signal cannot fully account for this positive PBR-NBR coupling and conclude that the local sensory network response reflects a combination of superimposed vascular and neuronal signals. More detailed quantification of physiological and noise contributions to the BOLD signal is required to fully understand the trial-by-trial PBR and NBR relationship compared with that of average responses. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Cryptogenic Stroke and Nonstenosing Intracranial Calcified Atherosclerosis.

PubMed

Kamel, Hooman; Gialdini, Gino; Baradaran, Hediyeh; Giambrone, Ashley E; Navi, Babak B; Lerario, Michael P; Min, James K; Iadecola, Costantino; Gupta, Ajay

2017-04-01

Because some cryptogenic strokes may result from large-artery atherosclerosis that goes unrecognized as it causes <50% luminal stenosis, we compared the prevalence of nonstenosing intracranial atherosclerotic plaques ipsilateral to cryptogenic cerebral infarcts versus the unaffected side using imaging biomarkers of calcium burden. In a prospective stroke registry, we identified patients with cerebral infarction limited to the territory of one internal carotid artery (ICA). We included patients with stroke of undetermined etiology and, as controls, patients with cardioembolic stroke. We used noncontrast computed tomography to measure calcification in both intracranial ICAs, including qualitative calcium scoring and quantitative scoring utilizing the Agatston-Janowitz (AJ) calcium scoring. Within subjects, the Wilcoxon signed-rank sum test for nonparametric paired data was used to compare the calcium burden in the ICA upstream of the infarction versus the ICA on the unaffected side. We obtained 440 calcium measures from 110 ICAs in 55 patients. Among 34 patients with stroke of undetermined etiology, we found greater calcium in the ICA ipsilateral to the infarction (mean Modified Woodcock Visual Scale score, 6.7 ± 4.6) compared with the contralateral side (5.4 ± 4.1) (P = .005). Among 21 patients with cardioembolic stroke, we found no difference in calcium burden ipsilateral to the infarction (6.7 ± 5.9) versus the contralateral side (7.3 ± 6.3) (P = .13). The results were similar using quantitative calcium measurements, including the AJ calcium scores. In patients with strokes of undetermined etiology, the burden of calcified intracranial large-artery plaque was associated with downstream cerebral infarction. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

The effects of anterior arcuate and dorsomedial frontal cortex lesions on visually guided eye movements: 2. Paired and multiple targets.

PubMed

Schiller, P H; Chou, I

2000-01-01

This study examined the effects of anterior arcuate and dorsomedial frontal cortex lesions on the execution of saccadic eye movements made to paired and multiple targets in rhesus monkeys. Identical paired targets were presented with various temporal asynchronies to determine the temporal offset required to yield equal probability choices to either target. In the intact animal equal probability choices were typically obtained when the targets appeared simultaneously. After unilateral anterior arcuate lesions a major shift arose in the temporal offset required to obtain equal probability choices for paired targets that necessitated presenting the target in the hemifield contralateral to the lesion more than 100 ms prior to the target in the ipsilateral hemifield. This deficit was still pronounced 1 year after the lesion. Dorsomedial frontal cortex lesions produced much smaller but significant shifts in target selection that recovered more rapidly. Paired lesions produced deficits similar to those observed with anterior arcuate lesions alone. Major deficits were also observed on a multiple target temporal discrimination task after anterior arcuate but not after dorsomedial frontal cortex lesions. These results suggest that the frontal eye fields that reside in anterior bank of the arcuate sulcus play an important role in temporal processing and in target selection. Dorsomedial frontal cortex, that contains the medial eye fields, plays a much less important role in the execution of these tasks.

Brain oscillatory signatures of motor tasks

PubMed Central

Birbaumer, Niels

2015-01-01

Noninvasive brain-computer-interfaces (BCI) coupled with prosthetic devices were recently introduced in the rehabilitation of chronic stroke and other disorders of the motor system. These BCI systems and motor rehabilitation in general involve several motor tasks for training. This study investigates the neurophysiological bases of an EEG-oscillation-driven BCI combined with a neuroprosthetic device to define the specific oscillatory signature of the BCI task. Controlling movements of a hand robotic orthosis with motor imagery of the same movement generates sensorimotor rhythm oscillation changes and involves three elements of tasks also used in stroke motor rehabilitation: passive and active movement, motor imagery, and motor intention. We recorded EEG while nine healthy participants performed five different motor tasks consisting of closing and opening of the hand as follows: 1) motor imagery without any external feedback and without overt hand movement, 2) motor imagery that moves the orthosis proportional to the produced brain oscillation change with online proprioceptive and visual feedback of the hand moving through a neuroprosthetic device (BCI condition), 3) passive and 4) active movement of the hand with feedback (seeing and feeling the hand moving), and 5) rest. During the BCI condition, participants received contingent online feedback of the decrease of power of the sensorimotor rhythm, which induced orthosis movement and therefore proprioceptive and visual information from the moving hand. We analyzed brain activity during the five conditions using time-frequency domain bootstrap-based statistical comparisons and Morlet transforms. Activity during rest was used as a reference. Significant contralateral and ipsilateral event-related desynchronization of sensorimotor rhythm was present during all motor tasks, largest in contralateral-postcentral, medio-central, and ipsilateral-precentral areas identifying the ipsilateral precentral cortex as an integral part of motor regulation. Changes in task-specific frequency power compared with rest were similar between motor tasks, and only significant differences in the time course and some narrow specific frequency bands were observed between motor tasks. We identified EEG features representing active and passive proprioception (with and without muscle contraction) and active intention and passive involvement (with and without voluntary effort) differentiating brain oscillations during motor tasks that could substantially support the design of novel motor BCI-based rehabilitation therapies. The BCI task induced significantly different brain activity compared with the other motor tasks, indicating neural processes unique to the use of body actuators control in a BCI context. PMID:25810484

Can the risk of secondary cancer induction after breast conserving therapy be reduced using intraoperative radiotherapy (IORT) with low-energy x-rays?

PubMed

Aziz, Muhammad Hammad; Schneider, Frank; Clausen, Sven; Blank, Elena; Herskind, Carsten; Afzal, Muhammad; Wenz, Frederik

2011-12-16

Radiation induced secondary cancers are a rare but severe late effect after breast conserving therapy. Intraoperative radiotherapy (IORT) is increasingly used during breast conserving surgery. The purpose of this analysis was to estimate secondary cancer risks after IORT compared to other modalities of breast radiotherapy (APBI - accelerated partial breast irradiation, EBRT - external beam radiotherapy). Computer-tomography scans of an anthropomorphic phantom were acquired with an INTRABEAM IORT applicator (diameter 4 cm) in the outer quadrant of the breast and transferred via DICOM to the treatment planning system. Ipsilateral breast, contralateral breast, ipsilateral lung, contralateral lung, spine and heart were contoured. An INTRABEAM source (50 kV) was defined with the tip of the drift tube at the center of the spherical applicator. A dose of 20 Gy at 0 mm depth from the applicator surface was prescribed for IORT and 34 Gy (5 days × 2 × 3.4 Gy) at 10 mm depth for APBI. For EBRT a total dose of 50 Gy in 2 Gy fractions was planned using two tangential fields with wedges. The mean and maximal doses, DVHs and volumes receiving more than 0.1 Gy and 4 Gy of organs at risk (OAR) were calculated and compared. The life time risk for secondary cancers was estimated according to NCRP report 116. IORT delivered the lowest maximal doses to contralateral breast (< 0.3 Gy), ipsilateral (1.8 Gy) and contralateral lung (< 0.3 Gy), heart (1 Gy) and spine (< 0.3 Gy). In comparison, maximal doses for APBI were 2-5 times higher. EBRT delivered a maximal dose of 10.4 Gy to the contralateral breast and 53 Gy to the ipsilateral lung. OAR volumes receiving more than 4 Gy were 0% for IORT, < 2% for APBI and up to 10% for EBRT (ipsilateral lung). The estimated risk for secondary cancer in the respective OAR is considerably lower after IORT and/or APBI as compared to EBRT. The calculations for maximal doses and volumes of OAR suggest that the risk of secondary cancer induction after IORT is lower than compared to APBI and EBRT.

Visual feedback-related changes in ipsilateral cortical excitability during unimanual movement: Implications for mirror therapy.

PubMed

Reissig, Paola; Garry, Michael I; Summers, Jeffery J; Hinder, Mark R

2014-01-01

Provision of a mirror image of a hand undertaking a motor task (i.e., mirror therapy) elicits behavioural improvements in the inactive hand. A greater understanding of the neural mechanisms underpinning this phenomenon is required to maximise its potential for rehabilitation across the lifespan, e.g., following hemiparesis or unilateral weakness. Young and older participants performed unilateral finger abductions with no visual feedback, with feedback of the active or passive hands, or with a mirror image of the active hand. Transcranial magnetic stimulation was used to assess feedback-related changes in two neurophysiological measures thought to be involved in inter-manual transfer of skill, namely corticospinal excitability (CSE) and intracortical inhibition (SICI) in the passive hemisphere. Task performance led to CSE increases, accompanied by decreases of SICI, in all visual feedback conditions relative to rest. However, the changes due to mirror feedback were not significantly different to those observed in the other (more standard) visual conditions. Accordingly, the unimanual motor action itself, rather than modifications in visual feedback, appears more instrumental in driving changes in CSE and SICI. Therefore, changes in CSE and SICI are unlikely to underpin the behavioural benefits of mirror therapy. We discuss implications for rehabilitation and directions of future research.

Subcortical functional reorganization due to early blindness.

PubMed

Coullon, Gaelle S L; Jiang, Fang; Fine, Ione; Watkins, Kate E; Bridge, Holly

2015-04-01

Lack of visual input early in life results in occipital cortical responses to auditory and tactile stimuli. However, it remains unclear whether cross-modal plasticity also occurs in subcortical pathways. With the use of functional magnetic resonance imaging, auditory responses were compared across individuals with congenital anophthalmia (absence of eyes), those with early onset (in the first few years of life) blindness, and normally sighted individuals. We find that the superior colliculus, a "visual" subcortical structure, is recruited by the auditory system in congenital and early onset blindness. Additionally, auditory subcortical responses to monaural stimuli were altered as a result of blindness. Specifically, responses in the auditory thalamus were equally strong to contralateral and ipsilateral stimulation in both groups of blind subjects, whereas sighted controls showed stronger responses to contralateral stimulation. These findings suggest that early blindness results in substantial reorganization of subcortical auditory responses. Copyright © 2015 the American Physiological Society.

Using Correlative Properties of Neighboring Pixels to Enhance Contrast-to-Noise Ratio of Abnormal Hippocampus in Patients With Intractable Epilepsy and Mesial Temporal Sclerosis.

PubMed

Parsons, Matthew S; Sharma, Aseem; Hildebolt, Charles

2018-06-12

To test whether an image-processing algorithm can aid in visualization of mesial temporal sclerosis on magnetic resonance imaging by selectively increasing contrast-to-noise ratio (CNR) between abnormal hippocampus and normal brain. In this Institutional Review Board-approved and Health Insurance Portability and Accountability Act-compliant study, baseline coronal fluid-attenuated inversion recovery images of 18 adults (10 females, eight males; mean age 41.2 years) with proven mesial temporal sclerosis were processed using a custom algorithm to produce corresponding enhanced images. Average (Hmean) and maximum (Hmax) CNR for abnormal hippocampus were calculated relative to normal ipsilateral white matter. CNR values for normal gray matter (GM) were similarly calculated using ipsilateral cingulate gyrus as the internal control. To evaluate effect of image processing on visual conspicuity of hippocampal signal alteration, a neuroradiologist masked to the side of hippocampal abnormality rated signal intensity (SI) of hippocampi on baseline and enhanced images using a five-point scale (definitely abnormal to definitely normal). Differences in Hmean, Hmax, GM, and SI ratings for abnormal hippocampi on baseline and enhanced images were assessed for statistical significance. Both Hmean and Hmax were significantly higher in enhanced images as compared to baseline images (p < 0.0001 for both). There was no significant difference in the GM between baseline and enhanced images (p = 0.9375). SI ratings showed a more confident identification of abnormality on enhanced images (p = 0.0001). Image-processing resulted in increased CNR of abnormal hippocampus without affecting the CNR of normal gray matter. This selective increase in conspicuity of abnormal hippocampus was associated with more confident identification of hippocampal signal alteration. Copyright © 2018 Academic Radiology. Published by Elsevier Inc. All rights reserved.

Reflections on mirror therapy: a systematic review of the effect of mirror visual feedback on the brain.

PubMed

Deconinck, Frederik J A; Smorenburg, Ana R P; Benham, Alex; Ledebt, Annick; Feltham, Max G; Savelsbergh, Geert J P

2015-05-01

Mirror visual feedback (MVF), a phenomenon where movement of one limb is perceived as movement of the other limb, has the capacity to alleviate phantom limb pain or promote motor recovery of the upper limbs after stroke. The tool has received great interest from health professionals; however, a clear understanding of the mechanisms underlying the neural recovery owing to MVF is lacking. We performed a systematic review to assess the effect of MVF on brain activation during a motor task. We searched PubMed, CINAHL, and EMBASE databases for neuroimaging studies investigating the effect of MVF on the brain. Key details for each study regarding participants, imaging methods, and results were extracted. The database search yielded 347 article, of which we identified 33 suitable for inclusion. Compared with a control condition, MVF increases neural activity in areas involved with allocation of attention and cognitive control (dorsolateral prefrontal cortex, posterior cingulate cortex, S1 and S2, precuneus). Apart from activation in the superior temporal gyrus and premotor cortex, there is little evidence that MVF activates the mirror neuron system. MVF increases the excitability of the ipsilateral primary motor cortex (M1) that projects to the "untrained" hand/arm. There is also evidence for ipsilateral projections from the contralateral M1 to the untrained/affected hand as a consequence of training with MVF. MVF can exert a strong influence on the motor network, mainly through increased cognitive penetration in action control, though the variance in methodology and the lack of studies that shed light on the functional connectivity between areas still limit insight into the actual underlying mechanisms. © The Author(s) 2014.

BOLD fMRI and DTI in strabismic amblyopes following occlusion therapy.

PubMed

Gupta, Shikha; Kumaran, Senthil S; Saxena, Rohit; Gudwani, Sunita; Menon, Vimala; Sharma, Pradeep

2016-08-01

Evaluation of brain cluster activation using the functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) was sought in strabismic amblyopes. In this hospital-based case-control cross-sectional study, fMRI and DTI were conducted in strabismic amblyopes before initiation of any therapy and after visual recovery following the administration of occlusion therapy. FMRI was performed in 10 strabismic amblyopic subjects (baseline group) and in 5 left strabismic amblyopic children post-occlusion therapy after two-line visual improvement. Ten age-matched healthy children with right ocular dominance formed control group. Structural and functional MRI was carried out on 1.5T MR scanner. The visual task consisted of 8 Hz flickering checkerboard with red dot and occasional green dot. Blood-oxygen-level-dependent (BOLD) fMRI was analyzed using statistical parametric mapping and DTI on NordicIce (NordicNeuroLab) softwares. Reduced occipital activation was elicited when viewing with the amblyopic eye in amblyopes. An 'ipsilateral to viewing eye' pattern of calcarine BOLD activation was observed in controls and left amblyopes. Activation of cortical areas associated with visual processing differed in relation to the viewing eye. Following visual recovery on occlusion therapy, enhanced activity in bilateral hemispheres in striate as well as extrastriate regions when viewing with either eye was seen. Improvement in visual acuity following occlusion therapy correlates with hemodynamic activity in amblyopes.

Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning.

PubMed

Waters, Sheena; Wiestler, Tobias; Diedrichsen, Jörn

2017-08-02

What is the role of ipsilateral motor and premotor areas in motor learning? One view is that ipsilateral activity suppresses contralateral motor cortex and, accordingly, that inhibiting ipsilateral regions can improve motor learning. Alternatively, the ipsilateral motor cortex may play an active role in the control and/or learning of unilateral hand movements. We approached this question by applying double-blind bihemispheric transcranial direct current stimulation (tDCS) over both contralateral and ipsilateral motor cortex in a between-group design during 4 d of unimanual explicit sequence training in human participants. Independently of whether the anode was placed over contralateral or ipsilateral motor cortex, bihemispheric stimulation yielded substantial performance gains relative to unihemispheric or sham stimulation. This performance advantage appeared to be supported by plastic changes in both hemispheres. First, we found that behavioral advantages generalized strongly to the untrained hand, suggesting that tDCS strengthened effector-independent representations. Second, functional imaging during speed-matched execution of trained sequences conducted 48 h after training revealed sustained, polarity-independent increases in activity in both motor cortices relative to the sham group. These results suggest a cooperative rather than competitive interaction of the two motor cortices during skill learning and suggest that bihemispheric brain stimulation during unimanual skill learning may be beneficial because it harnesses plasticity in the ipsilateral hemisphere. SIGNIFICANCE STATEMENT Many neurorehabilitation approaches are based on the idea that is beneficial to boost excitability in the contralateral hemisphere while attenuating that of the ipsilateral cortex to reduce interhemispheric inhibition. We observed that bihemispheric transcranial direct current stimulation (tDCS) with the excitatory anode either over contralateral or ipsilateral motor cortex facilitated motor learning nearly twice as strongly as unihemispheric tDCS. These increases in motor learning were accompanied by increases in fMRI activation in both motor cortices that outlasted the stimulation period, as well as increased generalization to the untrained hand. Collectively, our findings suggest a cooperative rather than a competitive role of the hemispheres and imply that it is most beneficial to harness plasticity in both hemispheres in neurorehabilitation of motor deficits. Copyright © 2017 Waters et al.

Walking Drosophila align with the e-vector of linearly polarized light through directed modulation of angular acceleration

PubMed Central

Velez, Mariel M.; Wernet, Mathias F.; Clark, Damon A.

2014-01-01

Understanding the mechanisms that link sensory stimuli to animal behavior is a central challenge in neuroscience. The quantitative description of behavioral responses to defined stimuli has led to a rich understanding of different behavioral strategies in many species. One important navigational cue perceived by many vertebrates and insects is the e-vector orientation of linearly polarized light. Drosophila manifests an innate orientation response to this cue (‘polarotaxis’), aligning its body axis with the e-vector field. We have established a population-based behavioral paradigm for the genetic dissection of neural circuits guiding polarotaxis to both celestial as well as reflected polarized stimuli. However, the behavioral mechanisms by which flies align with a linearly polarized stimulus remain unknown. Here, we present a detailed quantitative description of Drosophila polarotaxis, systematically measuring behavioral parameters that are modulated by the stimulus. We show that angular acceleration is modulated during alignment, and this single parameter may be sufficient for alignment. Furthermore, using monocular deprivation, we show that each eye is necessary for modulating turns in the ipsilateral direction. This analysis lays the foundation for understanding how neural circuits guide these important visual behaviors. PMID:24810784

Involvement of the primary motor cortex in controlling movements executed with the ipsilateral hand differs between left- and right-handers.

PubMed

van den Berg, Femke E; Swinnen, Stephan P; Wenderoth, Nicole

2011-11-01

Unimanual motor tasks, specifically movements that are complex or require high forces, activate not only the contralateral primary motor cortex (M1) but evoke also ipsilateral M1 activity. This involvement of ipsilateral M1 is asymmetric, such that the left M1 is more involved in motor control with the left hand than the right M1 in movements with the right hand. This suggests that the left hemisphere is specialized for movement control of either hand, although previous experiments tested mostly right-handed participants. In contrast, research on hemispheric asymmetries of ipsilateral M1 involvement in left-handed participants is relatively scarce. In the present study, left- and right-handed participants performed complex unimanual movements, whereas TMS was used to disrupt the activity of ipsilateral M1 in accordance with a "virtual lesion" approach. For right-handed participants, more disruptions were induced when TMS was applied over the dominant (left) M1. For left-handed participants, two subgroups could be distinguished, such that one group showed more disruptions when TMS was applied over the nondominant (left) M1, whereas the other subgroup showed more disruptions when the dominant (right) M1 was stimulated. This indicates that functional asymmetries of M1 involvement during ipsilateral movements are influenced by both hand dominance as well as left hemisphere specialization. We propose that the functional asymmetries in ipsilateral M1 involvement during unimanual movements are primarily attributable to asymmetries in the higher-order areas, although the contribution of transcallosal pathways and ipsilateral projections cannot be completely ruled out.

Structural and functional characteristics of commissural neurons in the superior colliculus of the hamster.

PubMed

Rhoades, R W; Mooney, R D; Szczepanik, A M; Klein, B G

1986-11-08

Intracellular recording and horseradish peroxidase (HRP) injection techniques were employed to delineate the structural and functional properties of superior collicular (SC) neurons in the hamster that were antidromically activated by electrical stimulation of the contralateral tectum. A total of 39 such cells were completely characterized, injected, and recovered. In ten of these, the axonal filling allowed us to reconstruct at least a portion of the terminal arborization in the SC contralateral to the labelled cell. Two of the recovered neurons were located in the stratum griseum superficiale (SGS), three were in the stratum opticum (SO), ten were in the stratum griseum intermediale (SGI), 11 were in the stratum album intermedium (SAI), 11 were in the stratum griseum profundum (SGP) and two were located in the stratum album profundum (SAP). The recovered cells were highly varied in both their morphological and their physiological characteristics. Somal areas ranged between 74 microns2 and 364 microns2, and the sample of recovered neurons included horizontal cells, narrow field vertical cells, and a variety of other multipolar neurons. Over one-third (38.5%) of the recovered cells were unresponsive, 2.6% were exclusively visual, 33.3% responded only to innocuous cutaneous stimuli, 10.2% were bimodal, 7.7% were specifically nociceptive, and 7.7% had complex (Rhoades, Mooney, and Jacquin: J. Neurosci. 3:1342-1354, '83) somatosensory receptive fields. We observed no clear-cut correlations between the structural and functional characteristics of these neurons. The conduction latencies of the commissural SC neurons ranged between 0.8 and 14.0 ms. The most rapidly conducting cells were located in the SGP and SAP. Conduction latency had a significant negative correlation with soma area. Labelled axons, in many cases, had at least one terminal arbor in a portion of the SC that was mirror symmetric with the location of the cell from which it originated. In several cases, however, commissural axons gave off a number of collaterals across the mediolateral extent of the tectum. commissural axonal terminations were visible only in the laminae ventral to the SO. Several commissural SC neurons also had extensive ipsilateral axon collaterals. Both the ipsilateral and commissural axon branches of these cells gave off en passant and terminal swellings.

Foxg1 regulates retinal axon pathfinding by repressing an ipsilateral program in nasal retina and by causing optic chiasm cells to exert a net axonal growth-promoting activity.

PubMed

Tian, Natasha M; Pratt, Thomas; Price, David J

2008-12-01

Mammalian binocular vision relies on the divergence of retinal ganglion cell axons at the optic chiasm, with strictly controlled numbers projecting contralaterally and ipsilaterally. In mouse, contralateral projections arise from the entire retina, whereas ipsilateral projections arise from ventrotemporal retina. We investigate how development of these patterns of projection is regulated by the contralateral determinant Foxg1, a forkhead box transcription factor expressed in nasal retina and at the chiasm. In nasal retina, loss of Foxg1 causes increased numbers of ipsilateral projections and ectopic expression of the ipsilateral determinants Zic2, Ephb1 and Foxd1, indicating that nasal retina is competent to express an ipsilateral program that is normally suppressed by Foxg1. Using co-cultures that combine Foxg1-expressing with Foxg1-null retinal explants and chiasm cells, we provide functional evidence that Foxg1 promotes contralateral projections through actions in nasal retina, and that in chiasm cells, Foxg1 is required for the generation of a hitherto unrecognized activity supporting RGC axon growth.

Forelimb training drives transient map reorganization in ipsilateral motor cortex

PubMed Central

Pruitt, David T.; Schmid, Ariel N.; Danaphongse, Tanya T.; Flanagan, Kate E.; Morrison, Robert A.; Kilgard, Michael P.; Rennaker, Robert L.; Hays, Seth A.

2016-01-01

Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use. After either 3 or 6 months of training, intracortical microstimulation (ICMS) mapping was performed to document motor representations of the trained forelimb in the hemisphere ipsilateral to that limb. Motor training for 3 months resulted in a robust expansion of right forelimb representation in the right motor cortex, demonstrating that skilled motor training drives map plasticity ipsilateral to the trained limb. After 6 months of training, the right forelimb representation in the right motor cortex was significantly smaller than the representation observed in rats trained for 3 months and similar to untrained controls, consistent with a normalization of motor cortex maps. Forelimb map area was not correlated with performance on the trained task, suggesting that task performance is maintained despite normalization of cortical maps. This study provides new insights into how the ipsilateral cortex changes in response to skilled learning and may inform rehabilitative strategies to enhance cortical plasticity to support recovery after brain injury. PMID:27392641

Forelimb training drives transient map reorganization in ipsilateral motor cortex.

PubMed

Pruitt, David T; Schmid, Ariel N; Danaphongse, Tanya T; Flanagan, Kate E; Morrison, Robert A; Kilgard, Michael P; Rennaker, Robert L; Hays, Seth A

2016-10-15

Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use. After either 3 or 6 months of training, intracortical microstimulation (ICMS) mapping was performed to document motor representations of the trained forelimb in the hemisphere ipsilateral to that limb. Motor training for 3 months resulted in a robust expansion of right forelimb representation in the right motor cortex, demonstrating that skilled motor training drives map plasticity ipsilateral to the trained limb. After 6 months of training, the right forelimb representation in the right motor cortex was significantly smaller than the representation observed in rats trained for 3 months and similar to untrained controls, consistent with a normalization of motor cortex maps. Forelimb map area was not correlated with performance on the trained task, suggesting that task performance is maintained despite normalization of cortical maps. This study provides new insights into how the ipsilateral cortex changes in response to skilled learning and may inform rehabilitative strategies to enhance cortical plasticity to support recovery after brain injury. Copyright © 2016 Elsevier B.V. All rights reserved.

Pourfour du Petit Syndrome Associated With Right Eye Pressure.

PubMed

Evans, Randolph W; Garibay, Adam; Foroozan, Rod

2017-06-01

Pourfour du Petit (PDP) syndrome is a rare disorder characterized by ipsilateral mydriasis, eyelid retraction, and hemifacial hyperhidrosis caused by hyperactivity of the ipsilateral oculosympathetic pathway. A case is presented of PDP syndrome associated with likely ipsilateral occipital neuralgia. We review the causes and co-morbidities and the clinical features of PDP. © 2017 American Headache Society.

Acupuncture for lateral epicondylitis (tennis elbow): study protocol for a randomized, practitioner-assessor blinded, controlled pilot clinical trial.

PubMed

Shin, Kyung-Min; Kim, Joo-Hee; Lee, Seunghoon; Shin, Mi-Suk; Kim, Tae-Hun; Park, Hyo-Ju; Lee, Min-Hee; Hong, Kwon-Eui; Lee, Seungdeok; Choi, Sun-Mi

2013-06-14

Lateral epicondylitis is the most frequent cause of pain around the elbow joint. It causes pain in the region of the elbow joint and results in dysfunction of the elbow and deterioration of the quality of life. The purpose of this study is to compare the effects of ipsilateral acupuncture, contralateral acupuncture and sham acupuncture on lateral epicondylitis. Forty-five subjects with lateral epicondylitis will be randomized into three groups: the ipsilateral acupuncture group, contralateral acupuncture group and the sham acupuncture group. The inclusion criteria will be as follows: (1) age between 19 and 65 years with pain due to one-sided lateral epicondylitis that persisted for at least four weeks, (2) with tenderness on pressure limited to regions around the elbow joint, (3) complaining of pain during resistive extension of the middle finger or the wrist, (4) with average pain of NRS 4 or higher during the last one week at a screening visit and (5) voluntarily agree to this study and sign a written consent. Acupuncture treatment will be given 10 times in total for 4 weeks to all groups. Follow up observations will be conducted after the completion of the treatment, 8 weeks and 12 weeks after the random assignment. Ipsilateral acupuncture group and contralateral acupuncture group will receive acupuncture on LI4, TE5, LI10, LI11, LU5, LI12 and two Ashi points. The sham acupuncture group will receive treatment on acupuncture points not related to the lateral epicondylitis using a non-invasive method. The needles will be maintained for 20 minutes. The primary outcome will be differences in the visual analogue scale (VAS) for elbow pain between the groups. The secondary outcome will be differences in patient-rated tennis elbow evaluation (PRTEE), pain-free/maximum grip strength (Dynamometer), pressure pain threshold, clinically relevant improvement, patient global assessment, and the EQ-5D. The data will be analyzed with the paired t-test and ANCOVA (P <0.05). The results of this study will allow evaluation of contralateral acupuncture from two aspects. First, if the contralateral acupuncture shows the effects similar to ipsilateral acupuncture, this will establish clinical basis for contralateral acupuncture. Second, if the effects of contralateral acupuncture are not comparable to the effects of ipsilateral acupuncture, but are shown to be similar to the effects of the sham acupuncture, we can establish the basis for using the same acupoints of the unaffected side as a control in acupuncture clinical studies. This trial has been registered with the 'Clinical Research Information Service (CRIS)', Republic of Korea: KCT0000628.

Acupuncture for lateral epicondylitis (tennis elbow): study protocol for a randomized, practitioner-assessor blinded, controlled pilot clinical trial

PubMed Central

2013-01-01

Background Lateral epicondylitis is the most frequent cause of pain around the elbow joint. It causes pain in the region of the elbow joint and results in dysfunction of the elbow and deterioration of the quality of life. The purpose of this study is to compare the effects of ipsilateral acupuncture, contralateral acupuncture and sham acupuncture on lateral epicondylitis. Methods/design Forty-five subjects with lateral epicondylitis will be randomized into three groups: the ipsilateral acupuncture group, contralateral acupuncture group and the sham acupuncture group. The inclusion criteria will be as follows: (1) age between 19 and 65 years with pain due to one-sided lateral epicondylitis that persisted for at least four weeks, (2) with tenderness on pressure limited to regions around the elbow joint, (3) complaining of pain during resistive extension of the middle finger or the wrist, (4) with average pain of NRS 4 or higher during the last one week at a screening visit and (5) voluntarily agree to this study and sign a written consent. Acupuncture treatment will be given 10 times in total for 4 weeks to all groups. Follow up observations will be conducted after the completion of the treatment, 8 weeks and 12 weeks after the random assignment. Ipsilateral acupuncture group and contralateral acupuncture group will receive acupuncture on LI4, TE5, LI10, LI11, LU5, LI12 and two Ashi points. The sham acupuncture group will receive treatment on acupuncture points not related to the lateral epicondylitis using a non-invasive method. The needles will be maintained for 20 minutes. The primary outcome will be differences in the visual analogue scale (VAS) for elbow pain between the groups. The secondary outcome will be differences in patient-rated tennis elbow evaluation (PRTEE), pain-free/maximum grip strength (Dynamometer), pressure pain threshold, clinically relevant improvement, patient global assessment, and the EQ-5D. The data will be analyzed with the paired t-test and ANCOVA (P <0.05). Discussion The results of this study will allow evaluation of contralateral acupuncture from two aspects. First, if the contralateral acupuncture shows the effects similar to ipsilateral acupuncture, this will establish clinical basis for contralateral acupuncture. Second, if the effects of contralateral acupuncture are not comparable to the effects of ipsilateral acupuncture, but are shown to be similar to the effects of the sham acupuncture, we can establish the basis for using the same acupoints of the unaffected side as a control in acupuncture clinical studies. Trial registration This trial has been registered with the ‘Clinical Research Information Service (CRIS)’, Republic of Korea: KCT0000628. PMID:23768129

Incidence and Predictors for Ipsilateral Hydronephrosis Following Ureteroscopic Lithotripsy.

PubMed

Barbour, Meredith L; Raman, Jay D

2015-09-01

To review our experience in using ureteroscopy (URS) with lithotripsy for renal or ureteral calculi to determine the incidence and predictors of postprocedural ipsilateral hydronephrosis. Records of 324 URS cases for renal or ureteral calculi with imaging performed 4-12 weeks postprocedure were reviewed. Ipsilateral hydronephrosis was determined by computed tomography scan or renal ultrasound. Univariate and multivariate analyses determined the factors associated with hydronephrosis. 176 men and 148 women with a median age of 50 years were included. Median stone size was 6 mm and operative duration was 60 minutes; 30% of patients had multiple calculi; and 35% had undergone a prior ipsilateral URS. Overall, 49 of 324 patients (15%) had evidence of hydronephrosis, with 65% of these patients having symptoms and 40% requiring ancillary procedures. On multivariate analysis, increasing stone diameter (odds ratio [OR] 8.9, 95% confidence interval [CI] 1.9-23.8, P = .03), prior ipsilateral URS (OR 7.7, 95% CI 1.8-28.2, P = .006), longer operative duration (OR 6.5, 95% CI 1.8-16.3, P = .02), and renal colic symptoms (OR 48.3, 95% CI 14.7-71.4, P <.001) independently predicted hydronephrosis. Conversely, other factors including stone impaction at procedure, ureteral dilation, use of an access sheath, intraoperative perforation, or use of a stent did not associate with ipsilateral hydronephrosis. In this contemporary cohort study, 15% of patients undergoing URS had evidence of ipsilateral hydronephrosis. Larger stone size, longer OR duration, prior ipsilateral URS, and recurrent colic were associated with an increased likelihood for this observation. Patients and stone cases with such characteristics likely warrant imaging modalities beyond plain radiography. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of using a single facial vein as outflow in full-face transplantation: A three-dimensional computed tomographic study.

PubMed

Rodriguez-Lorenzo, Andres; Audolfsson, Thorir; Wong, Corrine; Cheng, Angela; Arbique, Gary; Nowinski, Daniel; Rozen, Shai

2015-10-01

The aim of this study was to evaluate the contribution of a single unilateral facial vein in the venous outflow of total-face allograft using three-dimensional computed tomographic imaging techniques to further elucidate the mechanisms of venous complications following total-face transplant. Full-face soft-tissue flaps were harvested from fresh adult human cadavers. A single facial vein was identified and injected distally to the submandibular gland with a radiopaque contrast (barium sulfate/gelatin mixture) in every specimen. Following vascular injections, three-dimensional computed tomographic venographies of the faces were performed. Images were viewed using TeraRecon Software (Teracon, Inc., San Mateo, CA, USA) allowing analysis of the venous anatomy and perfusion in different facial subunits by observing radiopaque filling venous patterns. Three-dimensional computed tomographic venographies demonstrated a venous network with different degrees of perfusion in subunits of the face in relation to the facial vein injection side: 100% of ipsilateral and contralateral forehead units, 100% of ipsilateral and 75% of contralateral periorbital units, 100% of ipsilateral and 25% of contralateral cheek units, 100% of ipsilateral and 75% of contralateral nose units, 100% of ipsilateral and 75% of contralateral upper lip units, 100% of ipsilateral and 25% of contralateral lower lip units, and 50% of ipsilateral and 25% of contralateral chin units. Venographies of the full-face grafts revealed better perfusion in the ipsilateral hemifaces from the facial vein in comparison with the contralateral hemifaces. Reduced perfusion was observed mostly in the contralateral cheek unit and contralateral lower face including the lower lip and chin units. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Association of Ipsilateral Rib Fractures With Displacement of Midshaft Clavicle Fractures.

PubMed

Stahl, Daniel; Ellington, Matthew; Brennan, Kindyle; Brennan, Michael

2017-04-01

To determine whether the presence of ipsilateral rib fractures affects the rate of a clavicle fracture being unstable (>100% displacement). A retrospective review from 2002-2013 performed at a single level 1 trauma center evaluated 243 midshaft clavicle fractures. Single Level 1 trauma center. These fractures were subdivided into those with ipsilateral rib fractures (CIR; n = 149) and those without ipsilateral rib fractures (CnIR; n = 94). The amount of displacement was measured on the initial injury radiograph and subsequent follow-up radiographs. Fractures were classified into either <100% displacement or >100% displacement, based on anteroposterior radiographs. Ipsilateral rib fractures were recorded based on which number rib was fractured and the total number of fractured ribs. One hundred sixteen (78%) of the CIR group and 51 (54%) of the CnIR group were found to have >100% displacement at follow-up (P = 0.0047). Seventy-two percent of the CIR group demonstrated progression from <100% to >100% displacement of the fracture compared with only 54% of the CnIR group (P < 0.05). The odds ratio for progression of the clavicle fracture to >100% was 4.08 (P = 0.000194) when ribs 1-4 were fractured and not significant for rib fractures 5-8 or 9-12. The presence of concomitant ipsilateral rib fractures significantly increases the rate of midshaft clavicle fractures being >100% displaced. In addition, a fracture involving the upper one-third of the ribs significantly increases the rate of the clavicle fracture being >100% displaced on early follow-up. Clavicle fractures with associated ipsilateral rib fractures tend to demonstrate an increased amount of displacement on follow-up radiographs compared with those without ipsilateral rib fractures. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Ipsilateral fracture dislocation of the shoulder and elbow: A case report and literature review

PubMed Central

Behr, Ian; Blint, Andy; Trenhaile, Scott

2013-01-01

Ipsilateral dislocation of the shoulder and elbow is an uncommon injury. A literature review identified nine previously described cases. We are reporting a unique case of ipsilateral posterior shoulder dislocation and anterior elbow dislocation along with concomitant intra-articular fractures of both joints. This is the first report describing this combination of injuries. Successful treatment generally occurs with closed reduction of ipsilateral shoulder and elbow dislocations, usually reducing the elbow first. When combined with a fracture at one or both locations, closed reduction of the dislocations in conjunction with appropriate fracture management can result in a positive functional outcome. PMID:26403884

Quantitative Visualization of Dynamic Tracer Transportation in the Extracellular Space of Deep Brain Regions Using Tracer-Based Magnetic Resonance Imaging.

PubMed

Hou, Jin; Wang, Wei; Quan, Xianyue; Liang, Wen; Li, Zhiming; Chen, Deji; Han, Hongbin

2017-09-03

BACKGROUND This study assessed an innovative tracer-based magnetic resonance imaging (MRI) system to visualize the dynamic transportation of tracers in regions of deep brain extracellular space (ECS) and to measure transportation ability and ECS structure. MATERIAL AND METHODS Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) was the chosen tracer and was injected into the caudate nucleus and thalamus. Real-time dynamic transportation of Gd-DTPA in ECS was observed and the results were verified by laser scanning confocal microscopy. Using Transwell assay across the blood-brain barrier, a modified diffusion equation was further simplified. Effective diffusion coefficient D* and tortuosity λ were calculated. Immunohistochemical staining and Western blot analysis were used to investigate the extracellular matrix contributing to ECS structure. RESULTS Tracers injected into the caudate nucleus were transported to the ipsilateral frontal and temporal cortices away from the injection points, while both of them injected into the thalamus were only distributed on site. Although the caudate nucleus was closely adjacent to the thalamus, tracer transportation between partitions was not observed. In addition, D* and the λ showed statistically significant differences between partitions. ECS was shown to be a physiologically partitioned system, and its division is characterized by the unique distribution territory and transportation ability of substances located in it. Versican and Tenascin R are possible contributors to the tortuosity of ECS. CONCLUSIONS Tracer-based MRI will improve our understanding of the brain microenvironment, improve the techniques for local delivery of drugs, and highlight brain tissue engineering fields in the future.

Interaction of tinnitus suppression and hearing ability after cochlear implantation.

PubMed

Wang, Qian; Li, Jia-Nan; Lei, Guan-Xiong; Chen, Dai-Shi; Wang, Wei-Ze; Chen, Ai-Ting; Mong, Meng-Di; Li, Sun; Jiao, Qing-Shan; Yang, Shi-Ming

2017-10-01

To study the postoperative impact of cochlear implants (CIs) on tinnitus, as well as the impact of tinnitus on speech recognition with CI switched on. Fifty-two postlingual deafened CI recipients (21 males and 31 females) were assessed using an established Tinnitus Characteristics Questionnaire and Tinnitus Handicap Inventory (THI) before and after cochlear implantation. The tinnitus loudness was investigated when CI was switched on and off in CI recipients with persistent tinnitus. The relation between tinnitus loudness and recipients' satisfaction of cochlear implantation was analyzed by the visual analogue scale (VAS) score. With CI 'OFF', 42 CI recipients experienced tinnitus postimplant ipsilaterally and 44 contralaterally. Tinnitus was totally suppressed ipsilateral to the CI with CI 'ON' in 42.9%, partially suppressed in 42.9%, unchanged in 11.9% and aggravated in 2.4%. Tinnitus was totally suppressed contralaterally with CI 'ON' in 31.8% of CI recipients, partially suppressed in 47.7%, unchanged in 20.5%. Pearson correlation analysis showed that tinnitus loudness and the results of cochlear implant patients satisfaction was negatively correlated (r = .674, p < .001). The study suggests six-month CI activation can be effective for suppressing tinnitus. The tinnitus loudness may affect patients' satisfaction with the use of CI.

Feedback from visual cortical area 7 to areas 17 and 18 in cats: How neural web is woven during feedback.

PubMed

Yang, X; Ding, H; Lu, J

2016-01-15

To investigate the feedback effect from area 7 to areas 17 and 18, intrinsic signal optical imaging combined with pharmacological, morphological methods and functional magnetic resonance imaging (fMRI) was employed. A spatial frequency-dependent decrease in response amplitude of orientation maps was observed in areas 17 and 18 when area 7 was inactivated by a local injection of GABA, or by a lesion induced by liquid nitrogen freezing. The pattern of orientation maps of areas 17 and 18 after the inactivation of area 7, if they were not totally blurred, paralleled the normal one. In morphological experiments, after one point at the shallow layers within the center of the cat's orientation column of area 17 was injected electrophoretically with HRP (horseradish peroxidase), three sequential patches in layers 1, 2 and 3 of area 7 were observed. Employing fMRI it was found that area 7 feedbacks mainly to areas 17 and 18 on ipsilateral hemisphere. Therefore, our conclusions are: (1) feedback from area 7 to areas 17 and 18 is spatial frequency modulated; (2) feedback from area 7 to areas 17 and 18 occurs mainly ipsilaterally; (3) histological feedback pattern from area 7 to area 17 is weblike. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Severe ipsilateral carotid stenosis and middle cerebral artery disease in lacunar ischaemic stroke: innocent bystanders?

PubMed

Mead, G E; Lewis, S C; Wardlaw, J M; Dennis, M S; Warlow, C P

2002-03-01

Lacunar infarcts are thought to be mostly due to intracranial small vessel disease. Therefore, when a stroke patient with a relevant lacunar infarct does have severe ipsilateral internal carotid artery (ICA) or middle cerebral artery (MCA) disease, it is unclear whether the arterial disease is causative or coincidental. If causative, we would expect ICA/MCA disease to be more severe on the symptomatic side than on the asymptomatic side. Therefore, our aim was to compare the severity of ipsilateral with contralateral ICA and MCA disease in patients with lacunar ischaemic stroke. We studied 259 inpatients and outpatients with a recent lacunar ischaemic stroke and no other prior stroke. We used carotid Duplex ultrasound and transcranial Doppler (TCD) ultrasound to identify ICA and MCA disease, and compared our results with previously published data. In our study, there was no difference between the severity of ipsilateral and contralateral ICA stenosis within individuals (median difference 0%, Wilcoxon paired data p=0.24, comparing severity of ipsilateral and contralateral stenosis). The overall prevalence of severe ipsilateral stenosis was 5%, and the prevalence of severe contralateral stenosis was 4% (OR 1.6, 95% CI 0.6, 4.8). There was no difference in the prevalence of ipsilateral and contralateral MCA disease. A systematic review of the other available studies strengthened this conclusion. Carotid stenosis in patients with a lacunar ischaemic stroke may be coincidental. Further studies are required to elucidate the causes of lacunar stroke, and to evaluate the role of carotid endarterectomy.

The critical role of the external carotid artery in cerebral perfusion of patients with total occlusion of the internal carotid artery.

PubMed

Dalainas, I; Avgerinos, E D; Daskalopoulos, M E; Papapetrou, A; Papasideris, C P; Katsikas, V; Xiromeritis, K; Moulakakis, K; Gianakopoulos, T; Liapis, C D

2012-02-01

The ipsilateral external carotid artery (ECA) can potentially provide an important collateral pathway for cerebral blood flow in the presence of occlusion or severe stenosis of the internal carotid artery (ICA), recovering up to 15% of the middle cerebral arterial flow. The aim of the study is to elucidate the role of ECA in cerebral flow of patients with total ICA occlusion. Retrospective study of prospectively collected data of 139 patients with total ICA occlusions. The patients were divided to symptomatic and asymptomatic and were categorized in four subgroups according to the stenosis rates: A) ipsilateral ECA<70% and contralateral internal carotid artery stenosis <70%; B) ipsilateral ECA stenosis <70% and contralateral internal carotid artery stenosis ≥70%; C) ipsilateral ECA stenosis ≥70% and contralateral ICA stenosis <70%; D) ipsilateral ECA stenosis ≥70% and contralateral ICA stenosis ≥75%. Fifty eight (41.7%) patients were asymptomatic. The highest rate (48.2%) of asymptomatic patients was in Group A. Among patients with strokes, the highest rate belonged in groups C and D (44.4% and 50% respectively) where ipsilateral ECA stenosis was ≥70% irrespectively of the contralateral ICA patency. Ipsilateral external carotid artery stenosis ≥70% proved to be and independent risk factor for symptom presentation (P=0.013). The study reveals the significant role of ECA patency in cerebral flow in patients with ICA occlusion.

The Dynamics of the Stapedial Acoustic Reflex.

NASA Astrophysics Data System (ADS)

Moss, Sherrin Mary

Available from UMI in association with The British Library. This thesis aims to separate the neural and muscular components of the stapedial acoustic reflex, both anatomically and physiologically. It aims to present an hypothesis to account for the differences between ipsilateral and contralateral reflex characteristics which have so far been unexplained, and achieve a greater understanding of the mechanisms underlying the reflex dynamics. A technique enabling faithful reproduction of the time course of the reflex is used throughout the experimental work. The technique measures tympanic membrane displacement as a result of reflex stapedius muscle contraction. The recorded response can be directly related to the mechanics of the middle ear and stapedius muscle contraction. Some development of the technique is undertaken by the author. A model of the reflex neural arc and stapedius muscle dynamics is evolved that is based upon a second order system. The model is unique in that it includes a latency in the ipsilateral negative feedback loop. Oscillations commonly observed on reflex responses are seen to be produced because of the inclusion of a latency in the feedback loop. The model demonstrates and explains the complex relationships between neural and muscle dynamic parameters observed in the experimental work. This more comprehensive understanding of the interaction between the stapedius dynamics and the neural arc of the reflex would not usually have been possible using human subjects, coupled with a non-invasive measurement technique. Evidence from the experimental work revealed the ipsilateral reflex to have, on average, a 5 dB lower threshold than the contralateral reflex. The oscillatory charcteristics, and the steady state response, of the contralateral reflex are also seen to be significantly different from those of the ipsilateral reflex. An hypothesis to account for the experimental observations is proposed. It is propounded that chemical neurotransmitters, and their effect upon the contralateral reflex arc from the site of the superior olivary complex to the motoneurones innervating the stapedius, account for the difference between the contralateral and ipsilateral reflex thresholds and dynamic characteristics. In the past two years the measurement technique used for the experimental work has developed from an audiological to a neurological diagnostic tool. This has enabled the results from the study to be applied in the field for valuable biomechanical and neurological explanations of the reflex response. (Abstract shortened by UMI.).

Modulation of early cortical processing during divided attention to non-contiguous locations

PubMed Central

Frey, Hans-Peter; Schmid, Anita M.; Murphy, Jeremy W.; Molholm, Sophie; Lalor, Edmund C.; Foxe, John J.

2015-01-01

We often face the challenge of simultaneously attending to multiple non-contiguous regions of space. There is ongoing debate as to how spatial attention is divided under these situations. While for several years the predominant view was that humans could divide the attentional spotlight, several recent studies argue in favor of a unitary spotlight that rhythmically samples relevant locations. Here, this issue was addressed using high-density electrophysiology in concert with the multifocal m-sequence technique to examine visual evoked responses to multiple simultaneous streams of stimulation. Concurrently, we assayed the topographic distribution of alpha-band oscillatory mechanisms, a measure of attentional suppression. Participants performed a difficult detection task that required simultaneous attention to two stimuli in contiguous (undivided) or non-contiguous parts of space. In the undivided condition, the classical pattern of attentional modulation was observed, with increased amplitude of the early visual evoked response and increased alpha amplitude ipsilateral to the attended hemifield. For the divided condition, early visual responses to attended stimuli were also enhanced and the observed multifocal topographic distribution of alpha suppression was in line with the divided attention hypothesis. These results support the existence of divided attentional spotlights, providing evidence that the corresponding modulation occurs during initial sensory processing timeframes in hierarchically early visual regions and that suppressive mechanisms of visual attention selectively target distracter locations during divided spatial attention. PMID:24606564

Correlation of Longitudinal Gray Matter Volume Changes and Motor Recovery in Patients After Pontine Infarction.

PubMed

Wang, Peipei; Jia, Xiuqin; Zhang, Miao; Cao, Yanxiang; Zhao, Zhilian; Shan, Yi; Ma, Qingfeng; Qian, Tianyi; Wang, Jingjuan; Lu, Jie; Li, Kuncheng

2018-01-01

The mechanisms of motor functional recovery after pontine infarction (PI) remain unclear. Here, we assessed longitudinal changes in gray matter volume (GMV) and examined the relationship between GMV and clinical outcome. Fifteen patients with unilateral PI underwent magnetic resonance imaging and neurological exams five times during a period of 6 months. Another 15 healthy participants were enrolled as the normal control (NC) group and were examined with the same protocol. The MR exam included routine protocol and a 3D T1-weighted magnetization-prepared rapid acquisition gradient echo scan. Changes in GMV were assessed using voxel-based morphometry. Furthermore, the correlations between GMV changes in regions of interest and clinical scores were assessed. Compared with NCs, the decreased GMVs in the contralateral uvula of cerebellum and the ipsilateral tuber of cerebellum were detected at third month after stroke onset. At the sixth month after stroke onset, the decreased GMVs were detected in the contralateral culmen of cerebellum, putamen, as well as in the ipsilateral tuber/tonsil of cerebellum. Compared with NC, the PI group exhibited significant increases in GMV at each follow-up time point relative to stroke onset. Specifically, the significant GMV increase was found in the ipsilateral middle frontal gyrus and ventral anterior nucleus of thalamus at second week after stroke onset. At first month after stroke onset, the increased GMVs in the ipsilateral middle temporal gyrus were detected. The significant GMV increase in the ipsilateral mediodorsal thalamus was noted at third month after stroke onset. At the end of sixth month after stroke onset, the GMV increase was found in the ipsilateral mediodorsal thalamus, superior frontal gyrus, and the contralateral precuneus. Across five times during a period of 6-month, a negative correlation was observed between mean GMV in the contralateral uvula, culmen, putamen, and ipsilateral tuber/tonsil and mean Fugl-Meyer (FM) score. However, mean GMV in the ipsilateral mediodorsal thalamus was positively correlated with mean FM score. Our findings suggest that structural reorganization of the ipsilateral mediodorsal thalamus might contribute to motor functional recovery after PI.

Study of the influence of the laterality of mobile phone use on the SAR induced in two head models

NASA Astrophysics Data System (ADS)

Ghanmi, Amal; Varsier, Nadège; Hadjem, Abdelhamid; Conil, Emmanuelle; Picon, Odile; Wiart, Joe

2013-05-01

The objective of this paper is to investigate and to analyse the influence of the laterality of mobile phone use on the exposure of the brain to radio-frequencies (RF) and electromagnetic fields (EMF) from different mobile phone models using the finite-difference time-domain (FDTD) method. The study focuses on the comparison of the specific absorption rate (SAR) induced on the right and left sides of two numerical adult and child head models. The heads are exposed by both phone models operating in GSM frequency bands for both ipsilateral and contralateral configurations. A slight SAR difference between the two sides of the heads is noted. The results show that the variation between the left and the right sides is more important at 1800 MHz for an ipsilateral use. Indeed, at this frequency, the variation can even reach 20% for the SAR10g and the SAR1g induced in the head and in the brain, respectively. Moreover, the average SAR induced by the mobile phone in the half hemisphere of the brain in ipsilateral exposure is higher than in contralateral exposure. Owing to the superficial character of energy deposition at 1800 MHz, this difference in the SAR induced for the ipsilateral and contralateral usages is more significant at 1800 MHz than at 900 MHz. The results have shown that depending on the phantom head models, the SAR distribution in the brain can vary because of differences in anatomical proportions and in the geometry of the head models. The induced SAR in child head and in sub-regions of the brain is significantly higher (up to 30%) compared to the adult head. This paper confirms also that the shape/design of the mobile and the location of the antenna can have a large influence at high frequency on the exposure of the brain, particularly on the SAR distribution and on the distinguished brain regions.

Ipsilateral femoral shaft and vertical patella fracture: a case report

PubMed Central

Ozkan, Korhan; Eceviz, Engin; Sahin, Adem; Ugutmen, Ender

2009-01-01

Introduction A femoral shaft fracture with an ipsilateral patella fracture has been, to our knowledge, given only cursory attention in English-speaking literature. Case presentation A 15 year old male patient had hitten by a car to his motorcycle came to emergency room and he had been operated for his femoral shaft freacture and vertical patellar fracture which was iniatally missed. Conclusion To us it is vital to obtain CT scan of the patient’s knee if there is an ipsilateral femoral fracture with an ipsilateral knee effusion and a punction which reveals hematoma even in the absence of a fracture line seen in AP and lateral projections. PMID:19829933

Enhanced Visual Cortical Activation for Emotional Stimuli is Preserved in Patients with Unilateral Amygdala Resection

PubMed Central

Edmiston, E. Kale; McHugo, Maureen; Dukic, Mildred S.; Smith, Stephen D.; Abou-Khalil, Bassel; Eggers, Erica

2013-01-01

Emotionally arousing pictures induce increased activation of visual pathways relative to emotionally neutral images. A predominant model for the preferential processing and attention to emotional stimuli posits that the amygdala modulates sensory pathways through its projections to visual cortices. However, recent behavioral studies have found intact perceptual facilitation of emotional stimuli in individuals with amygdala damage. To determine the importance of the amygdala to modulations in visual processing, we used functional magnetic resonance imaging to examine visual cortical blood oxygenation level-dependent (BOLD) signal in response to emotionally salient and neutral images in a sample of human patients with unilateral medial temporal lobe resection that included the amygdala. Adults with right (n = 13) or left (n = 5) medial temporal lobe resections were compared with demographically matched healthy control participants (n = 16). In the control participants, both aversive and erotic images produced robust BOLD signal increases in bilateral primary and secondary visual cortices relative to neutral images. Similarly, all patients with amygdala resections showed enhanced visual cortical activations to erotic images both ipsilateral and contralateral to the lesion site. All but one of the amygdala resection patients showed similar enhancements to aversive stimuli and there were no significant group differences in visual cortex BOLD responses in patients compared with controls for either aversive or erotic images. Our results indicate that neither the right nor left amygdala is necessary for the heightened visual cortex BOLD responses observed during emotional stimulus presentation. These data challenge an amygdalo-centric model of emotional modulation and suggest that non-amygdalar processes contribute to the emotional modulation of sensory pathways. PMID:23825407

Visual cortex activation in kinesthetic guidance of reaching.

PubMed

Darling, W G; Seitz, R J; Peltier, S; Tellmann, L; Butler, A J

2007-06-01

The purpose of this research was to determine the cortical circuit involved in encoding and controlling kinesthetically guided reaching movements. We used (15)O-butanol positron emission tomography in ten blindfolded able-bodied volunteers in a factorial experiment in which arm (left/right) used to encode target location and to reach back to the remembered location and hemispace of target location (left/right side of midsagittal plane) varied systematically. During encoding of a target the experimenter guided the hand to touch the index fingertip to an external target and then returned the hand to the start location. After a short delay the subject voluntarily moved the same hand back to the remembered target location. SPM99 analysis of the PET data contrasting left versus right hand reaching showed increased (P < 0.05, corrected) neural activity in the sensorimotor cortex, premotor cortex and posterior parietal lobule (PPL) contralateral to the moving hand. Additional neural activation was observed in prefrontal cortex and visual association areas of occipital and parietal lobes contralateral and ipsilateral to the reaching hand. There was no statistically significant effect of target location in left versus right hemispace nor was there an interaction of hand and hemispace effects. Structural equation modeling showed that parietal lobe visual association areas contributed to kinesthetic processing by both hands but occipital lobe visual areas contributed only during dominant hand kinesthetic processing. This visual processing may also involve visualization of kinesthetically guided target location and use of the same network employed to guide reaches to visual targets when reaching to kinesthetic targets. The present work clearly demonstrates a network for kinesthetic processing that includes higher visual processing areas in the PPL for both upper limbs and processing in occipital lobe visual areas for the dominant limb.

Lateral medullary infarction with ipsilateral hemiparesis, lemniscal sensation loss and hypoglossal nerve palsy.

PubMed

Li, Xiaodi; Wang, Yuzhou

2014-04-01

Here, we present a rare case of a lateral medullary infarction with ipsilateral hemiparesis, lemniscal sensation loss and hypoglossal nerve palsy. In this case, we proved Opalski's hypothesis by diffusion tensor tractography that ipsilateral hemiparesis in a medullary infarction is due to the involvement of the decussated corticospinal tract. We found that the clinical triad of ipsilateral hemiparesis, lemniscal sensation loss and hypoglossal nerve palsy, which had been regarded as a variant of medial medullary syndrome, turned out to be caused by lateral lower medullary infarction. Therefore, this clinical triad does not imply the involvement of the anteromedial part of medulla oblongata, when it is hard to distinguish a massive lateral medullary infarction from a hemimedullary infarction merely from MR images. At last, we suggest that hyperreflexia and Babinski's sign may not be indispensable to the diagnosis of Opalski's syndrome and we propose that "hemimedullary infarction with ipsilateral hemiparesis" is intrinsically a variant of lateral medullary infarction.

Dosimetric comparison of moderate deep inspiration breath-hold and free-breathing intensity-modulated radiotherapy for left-sided breast cancer.

PubMed

Chi, F; Wu, S; Zhou, J; Li, F; Sun, J; Lin, Q; Lin, H; Guan, X; He, Z

2015-05-01

This study determined the dosimetric comparison of moderate deep inspiration breath-hold using active breathing control and free-breathing intensity-modulated radiotherapy (IMRT) after breast-conserving surgery for left-sided breast cancer. Thirty-one patients were enrolled. One free breathe and two moderate deep inspiration breath-hold images were obtained. A field-in-field-IMRT free-breathing plan and two field-in-field-IMRT moderate deep inspiration breath-holding plans were compared in the dosimetry to target volume coverage of the glandular breast tissue and organs at risks for each patient. The breath-holding time under moderate deep inspiration extended significantly after breathing training (P<0.05). There was no significant difference between the free-breathing and moderate deep inspiration breath-holding in the target volume coverage. The volume of the ipsilateral lung in the free-breathing technique were significantly smaller than the moderate deep inspiration breath-holding techniques (P<0.05); however, there was no significant difference between the two moderate deep inspiration breath-holding plans. There were no significant differences in target volume coverage between the three plans for the field-in-field-IMRT (all P>0.05). The dose to ipsilateral lung, coronary artery and heart in the field-in-field-IMRT were significantly lower for the free-breathing plan than for the two moderate deep inspiration breath-holding plans (all P<0.05); however, there was no significant difference between the two moderate deep inspiration breath-holding plans. The whole-breast field-in-field-IMRT under moderate deep inspiration breath-hold with active breathing control after breast-conserving surgery in left-sided breast cancer can reduce the irradiation volume and dose to organs at risks. There are no significant differences between various moderate deep inspiration breath-holding states in the dosimetry of irradiation to the field-in-field-IMRT target volume coverage and organs at risks. Copyright © 2015 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Woolly hair nevus with an ipsilateral associated epidermal nevus and additional findings of a white sponge nevus.

PubMed

Legler, Allison; Thomas, Tracy; Zlotoff, Barrett

2010-01-01

We report a case of a 16-year-old male with a woolly hair nevus, an associated ipsilateral epidermal nevus who also had a white plaque on his tongue, clinically diagnosed as a white sponge nevus. The concurrent findings of a white sponge nevus, a woolly hair nevus, and an ipsilateral epidermal nevus, to our knowledge, have not been previously reported.

Horner syndrome: clinical perspectives

PubMed Central

Kanagalingam, Sivashakthi; Miller, Neil R

2015-01-01

Horner syndrome consists of unilateral ptosis, an ipsilateral miotic but normally reactive pupil, and in some cases, ipsilateral facial anhidrosis, all resulting from damage to the ipsilateral oculosympathetic pathway. Herein, we review the clinical signs and symptoms that can aid in the diagnosis and localization of a Horner syndrome as well as the causes of the condition. We emphasize that pharmacologic testing can confirm its presence and direct further testing and management. PMID:28539793

Three-dimensional volumetric analysis of irradiated lung with adjuvant breast irradiation.

PubMed

Teh, Amy Yuen Meei; Park, Eileen J H; Shen, Liang; Chung, Hans T

2009-12-01

To retrospectively evaluate the dose-volume histogram data of irradiated lung in adjuvant breast radiotherapy (ABR) using a three-dimensional computed tomography (3D-CT)-guided planning technique; and to investigate the relationship between lung dose-volume data and traditionally used two-dimensional (2D) parameters, as well as their correlation with the incidence of steroid-requiring radiation pneumonitis (SRRP). Patients beginning ABR between January 2005 and February 2006 were retrospectively reviewed. Patients included were women aged >or=18 years with ductal carcinoma in situ or Stage I-III invasive carcinoma, who received radiotherapy using a 3D-CT technique to the breast or chest wall (two-field radiotherapy [2FRT]) with or without supraclavicular irradiation (three-field radiotherapy [3FRT]), to 50 Gy in 25 fractions. A 10-Gy tumor-bed boost was allowed. Lung dose-volume histogram parameters (V(10), V(20), V(30), V(40)), 2D parameters (central lung depth [CLD], maximum lung depth [MLD], and lung length [LL]), and incidence of SRRP were reported. A total of 89 patients met the inclusion criteria: 51 had 2FRT, and 38 had 3FRT. With 2FRT, mean ipsilateral V(10), V(20), V(30), V(40) and CLD, MLD, LL were 20%, 14%, 11%, and 8% and 2.0 cm, 2.1 cm, and 14.6 cm, respectively, with strong correlation between CLD and ipsilateral V(10-V40) (R(2) = 0.73-0.83, p < 0.0005). With 3FRT, mean ipsilateral V(10), V(20), V(30), and V(40) were 30%, 22%, 17%, and 11%, but its correlation with 2D parameters was poor. With a median follow-up of 14.5 months, 1 case of SRRP was identified. With only 1 case of SRRP observed, our study is limited in its ability to provide definitive guidance, but it does provide a starting point for acceptable lung irradiation during ABR. Further prospective studies are warranted.

Improvement in Cerebral and Ocular Hemodynamics Early after Carotid Endarterectomy in Patients of Severe Carotid Artery Stenosis with or without Contralateral Carotid Occlusion.

PubMed

Wang, Jian; Wang, Weici; Jin, Bi; Zhang, Yanrong; Xu, Ping; Xiang, Feixiang; Zheng, Yi; Chen, Juan; Sheng, Shi; Ouyang, Chenxi; Li, Yiqing

2016-01-01

Purpose. To investigate the alternation in cerebral and ocular blood flow velocity (BFV) in patients of carotid stenosis (CS) with or without contralateral carotid occlusion (CO) early after carotid endarterectomy (CEA). Patients and Methods. Nineteen patients underwent CEA for ≥50% CS. Fourteen patients had the unilateral CS, and five patients had the ipsilateral CS and the contralateral CO. Transcranial Doppler (TCD) and Color Doppler Imaging (CDI) were performed before and early after CEA. Results. In patients with unilateral CS, significant improvements in BFV were observed in anterior cerebral artery (ACA) and middle cerebral artery (MCA) on the ipsilateral side after CEA. In patients of ipsilateral CS and contralateral CO, significant improvements in BFV were observed in the ACA and MCA not only on the ipsilateral side but also on the contralateral side postoperatively. The ipsilateral ophthalmic artery (OA) retrograde flows in two patients were recovered to anterograde direction following CEA. The BFV in short posterior ciliary artery (SPCA) of the ipsilateral side significantly increased postoperatively irrespective of the presence of contralateral CO. Conclusions. CEA improved cerebral anterior circulation hemodynamics especially in patients of unilateral CS and contralateral CO, normalized the OA reverse flow, and increased the blood perfusion of SPCA.

Striatal infarction in the rat causes a transient reduction of tyrosine hydroxylase immunoreactivity in the ipsilateral substantia nigra.

PubMed

Soriano, M A; Justicia, C; Ferrer, I; Rodríguez-Farré, E; Planas, A M

1997-01-01

Dopaminergic neurons of the substantia nigra pars compacta were examined in the rat brain following striatal infarction subsequent to transient focal cerebral ischemia. Rats had the middle cerebral artery occluded for 2 h or were sham-operated, and tyrosine hydroxylase immunoreactivity was evaluated by Western blot and immunohistochemistry at different times ranging from 1 to 60 days after ischemia. The number of tyrosine hydroxylase-immunoreactive cells in the substantia nigra pars compacta was counted under the light microscope and compared to that in the contralateral side and controls. No changes of tyrosine hydroxylase immunoreactivity were detected in the ipsilateral versus the contralateral substantia nigra of sham-operated rats or 1 day after ischemia. However, a statistically significant reduction of tyrosine hydroxylase-immunoreactive cells became apparent in the ipsilateral compared with the contralateral substantia nigra at 7 and 14 days after ischemia. This reduction showed a clear recovery at 30 days after ischemia, and no signs of difference between the ipsilateral and the contralateral side were apparent by 60 days. Therefore, the reduction of tyrosine hydroxylase immunoreactivity in the ipsilateral substantia nigra was only transiently seen from 1 to 2 weeks following ischemia. The observed loss of tyrosine hydroxylase was not accompanied by signs of cell death or gliosis in the ipsilateral pars compacta. The present results show a transitory reduction of tyrosine hydroxylase immunoreactivity in the ipsilateral substantia nigra pars compacta after focal ischemia and suggest that striatal infarction causes a transient deficit of dopaminergic function.

Afferent connections of nervus facialis and nervus glossopharyngeus in the pigeon (Columba livia) and their role in feeding behavior.

PubMed

Dubbeldam, J L

1984-01-01

The afferent connections of the facial nerve and glossopharyngeal nerve in the pigeon have been studied with the Fink-Heimer I method after ganglion lesions. The nucleus ventrolateralis anterior of the solitary complex and an indistinct cell group S VII medial to the nucleus interpolaris of the descending trigeminal tract are the terminal fields for facial afferents. The n. ventrolateralis anterior also receives an important projection from the distal glossopharyngeal ganglion. Other projection areas of this ganglion are the n. presulcalis , n. centralis anterior, n. intermedius anterior and the parasolitary nucleus. Both ganglia have only ipsilateral projections. A lesion in the jugular ganglion complex causes degeneration throughout the ipsilateral solitary complex, in the contralateral n. commissuralis and n. centralis posterior and in the n. cuneatus externus. The lack of a substantial contribution to the trigeminal system is ascribed to the absence of mechanoreceptors in the tongue. The implications for the organization of neuronal pathways related to the feeding behavior are discussed.

Voltage-sensitive-dye imaging of microstimulation-evoked neural activity through intracortical horizontal and callosal connections in cat visual cortex.

PubMed

Suzurikawa, Jun; Tani, Toshiki; Nakao, Masayuki; Tanaka, Shigeru; Takahashi, Hirokazu

2009-12-01

Recently, intrinsic signal optical imaging has been widely used as a routine procedure for visualizing cortical functional maps. We do not, however, have a well-established imaging method for visualizing cortical functional connectivity indicating spatio-temporal patterns of activity propagation in the cerebral cortex. In the present study, we developed a novel experimental setup for investigating the propagation of neural activities combining the intracortical microstimulation (ICMS) technique with voltage sensitive dye (VSD) imaging, and demonstrated the feasibility of this setup applying to the measurement of time-dependent intra- and inter-hemispheric spread of ICMS-evoked excitation in the cat visual cortices, areas 17 and 18. A microelectrode array for the ICMS was inserted with a specially designed easy-to-detach electrode holder around the 17/18 transition zones (TZs), where the left and right hemispheres were interconnected via the corpus callosum. The microelectrode array was stably anchored in agarose without any holder, which enabled us to visualize evoked activities even in the vicinity of penetration sites as well as in a wide recording region that covered a part of both hemispheres. The VSD imaging could successfully visualize ICMS-evoked excitation and subsequent propagation in the visual cortices contralateral as well as ipsilateral to the ICMS. Using the orientation maps as positional references, we showed that the activity propagation patterns were consistent with previously reported anatomical patterns of intracortical and interhemispheric connections. This finding indicates that our experimental system can serve for the investigation of cortical functional connectivity.

Interhemispheric Transfer Time Asymmetry of Visual Information Depends on Eye Dominance: An Electrophysiological Study

PubMed Central

Chaumillon, Romain; Blouin, Jean; Guillaume, Alain

2018-01-01

The interhemispheric transfer of information is a fundamental process in the human brain. When a visual stimulus appears eccentrically in one visual-hemifield, it will first activate the contralateral hemisphere but also the ipsilateral one with a slight delay due to the interhemispheric transfer. This interhemispheric transfer of visual information is believed to be faster from the right to the left hemisphere in right-handers. Such an asymmetry is considered as a relevant fact in the context of the lateralization of the human brain. We show here using current source density (CSD) analyses of visually evoked potential (VEP) that, in right-handers and, to a lesser extent in left-handers, this asymmetry is in fact dependent on the sighting eye dominance, the tendency we have to prefer one eye for monocular tasks. Indeed, in right-handers, a faster interhemispheric transfer of visual information from the right to left hemisphere was observed only in participants with a right dominant eye (DE). Right-handers with a left DE showed the opposite pattern, with a faster transfer from the left to the right hemisphere. In left-handers, albeit a smaller number of participants has been tested and hence confirmation is required, only those with a right DE showed an asymmetrical interhemispheric transfer with a faster transfer from the right to the left hemisphere. As a whole these results demonstrate that eye dominance is a fundamental determinant of asymmetries in interhemispheric transfer of visual information and suggest that it is an important factor of brain lateralization. PMID:29515351

Interhemispheric Transfer Time Asymmetry of Visual Information Depends on Eye Dominance: An Electrophysiological Study.

PubMed

Chaumillon, Romain; Blouin, Jean; Guillaume, Alain

2018-01-01

The interhemispheric transfer of information is a fundamental process in the human brain. When a visual stimulus appears eccentrically in one visual-hemifield, it will first activate the contralateral hemisphere but also the ipsilateral one with a slight delay due to the interhemispheric transfer. This interhemispheric transfer of visual information is believed to be faster from the right to the left hemisphere in right-handers. Such an asymmetry is considered as a relevant fact in the context of the lateralization of the human brain. We show here using current source density (CSD) analyses of visually evoked potential (VEP) that, in right-handers and, to a lesser extent in left-handers, this asymmetry is in fact dependent on the sighting eye dominance, the tendency we have to prefer one eye for monocular tasks. Indeed, in right-handers, a faster interhemispheric transfer of visual information from the right to left hemisphere was observed only in participants with a right dominant eye (DE). Right-handers with a left DE showed the opposite pattern, with a faster transfer from the left to the right hemisphere. In left-handers, albeit a smaller number of participants has been tested and hence confirmation is required, only those with a right DE showed an asymmetrical interhemispheric transfer with a faster transfer from the right to the left hemisphere. As a whole these results demonstrate that eye dominance is a fundamental determinant of asymmetries in interhemispheric transfer of visual information and suggest that it is an important factor of brain lateralization.

Transcranial magnetic stimulation of the human brain: responses in muscles supplied by cranial nerves.

PubMed

Benecke, R; Meyer, B U; Schönle, P; Conrad, B

1988-01-01

The present investigation demonstrates that time-varying magnetic fields induced over the skull elicit distinct types of responses in muscles supplied by the cranial nerves both on the ipsilateral and the contralateral side. When the center of the copper coil was positioned 4 cm lateral to the vertex on a line from the vertex to the external auditory meatus, bilateral responses in the masseter, orbicularis oculi, mentalis, and sternocleidomastoideus muscles with a delay of about 10 to 14 ms after the stimulus occurred. Similar to the transcranially evoked muscle responses in hand muscles, the responses in the cranial muscles can be influenced in latency and amplitude by background excitation. It is concluded that these responses are induced by excitation of the face-associated motor cortex followed by multiple I-waves in the corticonuclear tract with both ipsilateral and contralateral projections to the corresponding motoneurones. Additionally, at higher stimulation strengths "short-latency" ipsilateral responses in muscles supplied by the trigeminal, facial, and accessory nerves occurred which we suggest are induced by direct stimulation of the peripheral cranial nerves in their intracisternal course. The present study confirms the bilateral projection of corticonuclear tracts in awake unanesthetised human subjects which has been observed by electrical stimulation on the exposed cortex during surgical procedures already decades ago. The present investigation will serve as a basis for the assessment of pathophysiological mechanisms involving the corticonuclear system or the peripheral cranial nerves in their proximal parts in awake humans.

Training Efficiency and Transfer Success in an Extended Real-Time Functional MRI Neurofeedback Training of the Somatomotor Cortex of Healthy Subjects

PubMed Central

Auer, Tibor; Schweizer, Renate; Frahm, Jens

2015-01-01

This study investigated the level of self-regulation of the somatomotor cortices (SMCs) attained by an extended functional magnetic resonance imaging (fMRI) neurofeedback training. Sixteen healthy subjects performed 12 real-time functional magnetic resonance imaging neurofeedback training sessions within 4 weeks, involving motor imagery of the dominant right as well as the non-dominant left hand. Target regions of interests in the SMC were individually localized prior to the training by overt finger movements. The feedback signal (FS) was defined as the difference between fMRI activation in the contra- and ipsilateral SMC and visually presented to the subjects. Training efficiency was determined by an off-line general linear model analysis determining the fMRI percent signal changes in the SMC target areas accomplished during the neurofeedback training. Transfer success was assessed by comparing the pre- and post-training transfer task, i.e., the neurofeedback paradigm without the presentation of the FS. Group results show a distinct increase in feedback performance (FP) in the transfer task for the trained group compared to a matched untrained control group, as well as an increase in the time course of the training, indicating an efficient training and a successful transfer. Individual analysis revealed that the training efficiency was not only highly correlated to the transfer success but also predictive. Trainings with at least 12 efficient training runs were associated with a successful transfer outcome. A group analysis of the hemispheric contributions to the FP showed that it is mainly driven by increased fMRI activation in the contralateral SMC, although some individuals relied on ipsilateral deactivation. Training and transfer results showed no difference between left- and right-hand imagery, with a slight indication of more ipsilateral deactivation in the early right-hand trainings. PMID:26500521

Automated objective characterization of visual field defects in 3D

NASA Technical Reports Server (NTRS)

Fink, Wolfgang (Inventor)

2006-01-01

A method and apparatus for electronically performing a visual field test for a patient. A visual field test pattern is displayed to the patient on an electronic display device and the patient's responses to the visual field test pattern are recorded. A visual field representation is generated from the patient's responses. The visual field representation is then used as an input into a variety of automated diagnostic processes. In one process, the visual field representation is used to generate a statistical description of the rapidity of change of a patient's visual field at the boundary of a visual field defect. In another process, the area of a visual field defect is calculated using the visual field representation. In another process, the visual field representation is used to generate a statistical description of the volume of a patient's visual field defect.

Engagement of the left extrastriate body area during body-part metaphor comprehension.

PubMed

Lacey, Simon; Stilla, Randall; Deshpande, Gopikrishna; Zhao, Sinan; Stephens, Careese; McCormick, Kelly; Kemmerer, David; Sathian, K

2017-03-01

Grounded cognition explanations of metaphor comprehension predict activation of sensorimotor cortices relevant to the metaphor's source domain. We tested this prediction for body-part metaphors using functional magnetic resonance imaging while participants heard sentences containing metaphorical or literal references to body parts, and comparable control sentences. Localizer scans identified body-part-specific motor, somatosensory and visual cortical regions. Both subject- and item-wise analyses showed that, relative to control sentences, metaphorical but not literal sentences evoked limb metaphor-specific activity in the left extrastriate body area (EBA), paralleling the EBA's known visual limb-selectivity. The EBA focus exhibited resting-state functional connectivity with ipsilateral semantic processing regions. In some of these regions, the strength of resting-state connectivity correlated with individual preference for verbal processing. Effective connectivity analyses showed that, during metaphor comprehension, activity in some semantic regions drove that in the EBA. These results provide converging evidence for grounding of metaphor processing in domain-specific sensorimotor cortical activity. Published by Elsevier Inc.

Monitoring proteins using in vivo near-infrared time-domain optical imaging after 2-O-hexyldiglycerol-mediated transfer to the brain.

PubMed

Hülper, Petra; Dullin, Christian; Kugler, Wilfried; Lakomek, Max; Erdlenbruch, Bernhard

2011-04-01

The aim of the present study was to gain insight into the penetration, biodistribution, and fate of globulins in the brain after 2-O-hexyldiglycerol-induced blood-brain barrier opening. The spatial distribution of fluorescence probes was investigated after blood-brain barrier opening with intracarotid 2-O-hexyldiglycerol injection. Fluorescence intensity was visualized by microscopy (mice and rats) and by in vivo time-domain optical imaging. There was an increased 2-O-hexyldiglycerol-mediated transfer of fluorescence-labeled globulins into the ipsilateral hemisphere. Sequential in vivo measurements revealed that the increase in protein concentration lasted at least 96 h after administration. Ex vivo detection of tissue fluorescence confirmed the results obtained in vivo. Globulins enter the healthy brain in conjunction with 2-O-hexyldiglycerol. Sequential in vivo near-infrared fluorescence measurements enable the visualization of the spatial distribution of antibodies in the brain of living small animals.

Cross-sectional echocardiographic diagnosis of azygos continuation of the inferior vena cava.

PubMed

Huhta, J C; Smallhorn, J F; Macartney, F J

1984-01-01

Azygos continuation of the inferior vena cava has importance for both the invasive diagnosis of congenital heart disease by catheterization and for surgical treatment. Cross-sectional echocardiography was used to examine 1,000 patients (1 day to 16 years, mean 3.3 years) who also had angiographic or surgical confirmation. Twenty-eight patients (3%) had azygos continuation (left 13, right 14, bilateral 1) and, in 26 patients, the hepatic portion of the inferior vena cava was absent. Azygos continuation was prospectively detected in all and was directly visualized in subcostal scans as a venous structure posterior to the aorta coursing behind the heart and not entering the inferior aspect of either atrium in 26/28 (93%). Azygos connection to the ipsilateral superior vena cava or atrium was correctly predicted in all. The inferior vena cava was visualized in all patients without azygos continuation, except one neonate with omphalocele. We conclude that cross-sectional echocardiography can accurately detect azygos continuation of the inferior vena cava and predict its side and connection.

mRNAs coding for neurotransmitter receptors and voltage-gated sodium channels in the adult rabbit visual cortex after monocular deafferentiation

PubMed Central

Nguyen, Quoc-Thang; Matute, Carlos; Miledi, Ricardo

1998-01-01

It has been postulated that, in the adult visual cortex, visual inputs modulate levels of mRNAs coding for neurotransmitter receptors in an activity-dependent manner. To investigate this possibility, we performed a monocular enucleation in adult rabbits and, 15 days later, collected their left and right visual cortices. Levels of mRNAs coding for voltage-activated sodium channels, and for receptors for kainate/α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), N-methyl-d-aspartate (NMDA), γ-aminobutyric acid (GABA), and glycine were semiquantitatively estimated in the visual cortices ipsilateral and contralateral to the lesion by the Xenopus oocyte/voltage-clamp expression system. This technique also allowed us to study some of the pharmacological and physiological properties of the channels and receptors expressed in the oocytes. In cells injected with mRNA from left or right cortices of monocularly enucleated and control animals, the amplitudes of currents elicited by kainate or AMPA, which reflect the abundance of mRNAs coding for kainate and AMPA receptors, were similar. There was no difference in the sensitivity to kainate and in the voltage dependence of the kainate response. Responses mediated by NMDA, GABA, and glycine were unaffected by monocular enucleation. Sodium channel peak currents, activation, steady-state inactivation, and sensitivity to tetrodotoxin also remained unchanged after the enucleation. Our data show that mRNAs for major neurotransmitter receptors and ion channels in the adult rabbit visual cortex are not obviously modified by monocular deafferentiation. Thus, our results do not support the idea of a widespread dynamic modulation of mRNAs coding for receptors and ion channels by visual activity in the rabbit visual system. PMID:9501250

Combined SCI and TBI: Recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement

PubMed Central

Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L.; Creasey, Graham H.; Manley, Geoffrey T.; Ferguson, Adam R.; Bresnahan, Jacqueline C.; Beattie, Michael S.

2015-01-01

A significant proportion (estimates range from 16–74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI + TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6 weeks, in the paw placement test, SCI + contralateral TBI produced a profound deficit that failed to recover, but SCI + ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI + contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI + contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. PMID:23770071

Combined SCI and TBI: recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement.

PubMed

Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L; Creasey, Graham H; Manley, Geoffrey T; Ferguson, Adam R; Bresnahan, Jacqueline C; Beattie, Michael S

2013-10-01

A significant proportion (estimates range from 16 to 74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI+TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6weeks, in the paw placement test, SCI+contralateral TBI produced a profound deficit that failed to recover, but SCI+ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI+contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI+contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. Copyright © 2013 Elsevier Inc. All rights reserved.

Repeat sentinel lymph node biopsy in patients with ipsilateral recurrent breast cancer after breast-conserving therapy and negative sentinel lymph node biopsy: a prospective study.

PubMed

Folli, Secondo; Falco, Giuseppe; Mingozzi, Matteo; Buggi, Federico; Curcio, Annalisa; Ferrari, Guglielmo; Taffurelli, Mario; Regolo, Lea; Nanni, Oriana

2016-04-01

Patients with ipsilateral breast tumor recurrence or new ipsilateral primary tumor after previous breast conservative surgery with negative sentinel lymph node biopsy need a new axillary staging procedure. However, the best surgical option, i.e. repeat sentinel lymph node biopsy or axillary lymph node dissection, is still debated. Purpose of the study is to assess the performance of repeat sentinel lymph node biopsy. In a multicenter study, lymph node biopsy completed by back-up axillary lymph node dissection was undertaken for ipsilateral breast tumor recurrence or new ipsilateral primary tumor. Tracer uptake was used to identify and isolate the sentinel lymph node during surgery, and it was classified after staining with hematoxylin and eosin and monoclonal anti-cytokeratin antibodies. Aside from negative predictive value, overall accuracy and false-negative rate of repeat sentinel lymph node biopsy were assessed. A multicenter, prospective study was conducted performing 30 repeat sentinel lymph node biopsy completed by back-up axillary lymph node dissection for ipsilateral breast tumor recurrence or new ipsilateral primary tumor in patients formerly treated with previous breast conservative surgery and negative sentinel lymph node biopsy. Negative predictive value, overall accuracy and false-negative rate of repeat sentinel lymph node biopsy were assessed. Sentinel lymph nodes were mapped in 27 patients out of 30 (90%). Aberrant drainage pathways were observed in one patient (3.7%). Tracer uptake was sufficient to identify and isolate the sentinel lymph node during surgery in 23 cases (76.6%); the patients in whom lymphoscintigraphy failed or no sentinel lymph nodes could be isolated underwent axillary lymph node dissection. The negative predictive value was 95.2%, the accuracy was 95.6% and the false-negative rate was 33%. Repeat sentinel lymph node biopsy is feasible and accurate, with a high negative predictive value. Patients with ipsilateral breast tumor recurrence or new ipsilateral primary tumor after previous breast conservative surgery and negative sentinel lymph node biopsy can be treated with repeat sentinel lymph node biopsy for the axillary staging and can be spared axillary dissection in case of absence of metastases. However, repeat sentinel lymph node biopsy may prove technically impracticable in about one quarter of cases and thus axillary lymph node dissection remains the only viable option in such instance.

Incidental Prophylactic Nodal Irradiation and Patterns of Nodal Relapse in Inoperable Early Stage NSCLC Patients Treated With SBRT: A Case-Matched Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lao, Louis; Department of Radiation Oncology, Auckland City Hospital, Auckland; Hope, Andrew J.

2014-09-01

Purpose: Reported rates of non-small cell lung cancer (NSCLC) nodal failure following stereotactic body radiation therapy (SBRT) are lower than those reported in the surgical series when matched for stage. We hypothesized that this effect was due to incidental prophylactic nodal irradiation. Methods and Materials: A prospectively collected group of medically inoperable early stage NSCLC patients from 2004 to 2010 was used to identify cases with nodal relapses. Controls were matched to cases, 2:1, controlling for tumor volume (ie, same or greater) and tumor location (ie, same lobe). Reference (normalized to equivalent dose for 2-Gy fractions [EQD2]) point doses atmore » the ipsilateral hilum and carina, demographic data, and clinical outcomes were extracted from the medical records. Univariate conditional logistical regression analyses were performed with variables of interest. Results: Cases and controls were well matched except for size. The controls, as expected, had larger gross tumor volumes (P=.02). The mean ipsilateral hilar doses were 9.6 Gy and 22.4 Gy for cases and controls, respectively (P=.014). The mean carinal doses were 7.0 Gy and 9.2 Gy, respectively (P=.13). Mediastinal nodal relapses, with and without ipsilateral hilar relapse, were associated with mean ipsilateral hilar doses of 3.6 Gy and 19.8 Gy, respectively (P=.01). The conditional density plot appears to demonstrate an inverse dose-effect relationship between ipsilateral hilar normalized total dose and risk of ipsilateral hilar relapse. Conclusions: Incidental hilar dose greater than 20 Gy is significantly associated with fewer ipsilateral hilar relapses in inoperable early stage NSCLC patients treated with SBRT.« less

Differential involvement of ipsilateral and contralateral spinal cord astrocyte D-serine in carrageenan-induced mirror-image pain: role of σ1 receptors and astrocyte gap junctions.

PubMed

Choi, Hoon-Seong; Roh, Dae-Hyun; Yoon, Seo-Yeon; Choi, Sheu-Ran; Kwon, Soon-Gu; Kang, Suk-Yun; Moon, Ji-Young; Han, Ho-Jae; Beitz, Alvin J; Lee, Jang-Hern

2018-02-01

Although we have recently demonstrated that spinal astrocyte gap junctions mediate the development of mirror-image pain (MIP), it is still unclear which astrocyte-derived factor is responsible for the development of MIP and how its production is controlled. In the present study, we focused on the role of ipsilateral versus contralateral D-serine in the development of MIP and investigated the possible involvement of σ1 receptors and gap junctions in astrocyte D-serine production. Following carrageenan injection, mechanical allodynia was tested at various time points to examine the effect of individual drugs. Immunohistochemistry and Western blot analyses were performed to clarify the expression levels of spinal D-serine, serine racemase, σ1 receptors and connexin 43. The expression of ipsilateral D-serine was up-regulated during the early phase of inflammation, while contralateral D-serine increased during the later phase of inflammation. The pharmacological inhibition of D-serine during the early phase blocked the development of both ipsilateral and contralateral mechanical allodynia. However, the inhibition of D-serine during the later phase of inflammation blocked contralateral, but not ipsilateral mechanical allodynia. Furthermore, the inhibition of σ1 receptors during the earlier phase of inflammation inhibited the increase in ipsilateral D-serine. Conversely, the blockade of astrocyte gap junctions suppressed the up-regulation of contralateral D-serine during the later phase of inflammation. Spinal astrocyte D-serine plays an important role in the development of mirror-image pain. Furthermore, σ1 receptors and astrocyte gap junction signalling mediate ipsilateral and contralateral D-serine production respectively. © 2017 The British Pharmacological Society.

Facilitation of corticospinal excitability according to motor imagery and mirror therapy in healthy subjects and stroke patients.

PubMed

Kang, Youn Joo; Ku, Jeonghun; Kim, Hyun Jung; Park, Hae Kyung

2011-12-01

To delineate the changes in corticospinal excitability when individuals are asked to exercise their hand using observation, motor imagery, voluntary exercise, and exercise with a mirror. The participants consisted of 30 healthy subjects and 30 stroke patients. In healthy subjects, the amplitudes and latencies of motor evoked potential (MEP) were obtained using seven conditions: (A) rest; (B) imagery; (C) observation and imagery of the hand activity of other individuals; (D) observation and imagery of own ipsilateral hand activity; (E) observation and imagery of the hand activity of another individual with a mirror; (F) observation and imagery of own symmetric ipsilateral hand activity (thumb abduction) with a mirror; and (G) observation and imagery of own asymmetric ipsilateral hand activity (little finger abduction) with a mirror. In stroke patients, MEPs were obtained in the A, C, D, E, F conditions. In both groups, increment of the percentage MEP amplitude (at rest) and latency decrement of MEPs were significantly higher during the observation of the activity of the hand of another individual with a mirror and during symmetric ipsilateral hand activity on their own hand with a mirror than they were without a mirror. In healthy subjects, the increment of percentage MEP amplitude and latency decrement were significantly higher during the observation of the symmetric ipsilateral hand activity with a mirror compared to the observation of the activity of the asymmetric ipsilateral hand with a mirror of their own hand. In both groups, corticospinal excitability was facilitated by viewing the mirror image of the activity of the ipsilateral hand. These findings provide neurophysiological evidence supporting the application of various mirror imagery programs during stroke rehabilitation.

Facilitation of Corticospinal Excitability According to Motor Imagery and Mirror Therapy in Healthy Subjects and Stroke Patients

PubMed Central

Kang, Youn Joo; Ku, Jeonghun; Kim, Hyun Jung

2011-01-01

Objective To delineate the changes in corticospinal excitability when individuals are asked to exercise their hand using observation, motor imagery, voluntary exercise, and exercise with a mirror. Method The participants consisted of 30 healthy subjects and 30 stroke patients. In healthy subjects, the amplitudes and latencies of motor evoked potential (MEP) were obtained using seven conditions: (A) rest; (B) imagery; (C) observation and imagery of the hand activity of other individuals; (D) observation and imagery of own ipsilateral hand activity; (E) observation and imagery of the hand activity of another individual with a mirror; (F) observation and imagery of own symmetric ipsilateral hand activity (thumb abduction) with a mirror; and (G) observation and imagery of own asymmetric ipsilateral hand activity (little finger abduction) with a mirror. In stroke patients, MEPs were obtained in the A, C, D, E, F conditions. Results In both groups, increment of the percentage MEP amplitude (at rest) and latency decrement of MEPs were significantly higher during the observation of the activity of the hand of another individual with a mirror and during symmetric ipsilateral hand activity on their own hand with a mirror than they were without a mirror. In healthy subjects, the increment of percentage MEP amplitude and latency decrement were significantly higher during the observation of the symmetric ipsilateral hand activity with a mirror compared to the observation of the activity of the asymmetric ipsilateral hand with a mirror of their own hand. Conclusion In both groups, corticospinal excitability was facilitated by viewing the mirror image of the activity of the ipsilateral hand. These findings provide neurophysiological evidence supporting the application of various mirror imagery programs during stroke rehabilitation. PMID:22506202

High frequency electrical stimulation concurrently induces central sensitization and ipsilateral inhibitory pain modulation.

PubMed

Vo, L; Drummond, P D

2013-03-01

In healthy humans, analgesia to blunt pressure develops in the ipsilateral forehead during various forms of limb pain. The aim of the current study was to determine whether this analgesic response is induced by ultraviolet B radiation (UVB), which evokes signs of peripheral sensitization, or by high-frequency electrical stimulation (HFS), which triggers signs of central sensitization. Before and after HFS and UVB conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the treated site in the forearm. In addition, sensitivity to blunt pressure was measured bilaterally in the forehead. The effect of ipsilateral versus contralateral temple cooling on electrically evoked pain in the forearm was then examined, to determine whether HFS or UVB conditioning altered inhibitory pain modulation. UVB conditioning triggered signs of peripheral sensitization, whereas HFS conditioning triggered signs of central sensitization. Importantly, ipsilateral forehead analgesia developed after HFS but not UVB conditioning. In addition, decreases in electrically evoked pain at the HFS-treated site were greater during ipsilateral than contralateral temple cooling, whereas decreases at the UVB-treated site were similar during both procedures. HFS conditioning induced signs of central sensitization in the forearm and analgesia both in the ipsilateral forehead and the HFS-treated site. This ipsilateral analgesia was not due to peripheral sensitization or other non-specific effects, as it failed to develop after UVB conditioning. Thus, the supra-spinal mechanisms that evoke central sensitization might also trigger a hemilateral inhibitory pain modulation process. This inhibitory process could sharpen the boundaries of central sensitization or limit its spread. © 2012 European Federation of International Association for the Study of Pain Chapters.

Does Roller Massage With a Foam Roll Change Pressure Pain Threshold of the Ipsilateral Lower Extremity Antagonist and Contralateral Muscle Groups? An Exploratory Study.

PubMed

Cheatham, Scott W; Kolber, Morey J

2018-03-01

Foam rolling is a popular intervention used by allied health professionals and the general population. Current research suggests that foam rolling may have an effect on the ipsilateral antagonist muscle group and produce a cross-over effect in the muscles of the contralateral limb. The purpose of this study was to examine the acute effects of foam rolling to the left quadriceps on ipsilateral antagonist hamstrings and contralateral quadriceps muscle group pressure pain threshold (PPT). Through this research, we sought to gather data to further develop the methodology for future studies of this intervention. A pretest-posttest exploratory study. University kinesiology laboratory. 21 healthy adults (age = 27.52 ± 8.9 y). Video-guided foam roll intervention on the left quadriceps musculature. Ipsilateral hamstring (antagonist) and contralateral quadriceps muscle PPT. A significant difference was found between pretest to posttest measures for the ipsilateral hamstrings (t[20] = -6.2, P < 0.001) and contralateral quadriceps (t[20] = -9.1, P < 0.001) suggesting an increase in PPT. These findings suggest that foam rolling of the quadriceps musculature may have an acute effect on the PPT of the ipsilateral hamstrings and contralateral quadriceps muscles. Clinicians should consider these results to be exploratory and future investigations examining this intervention on PPT is warranted.

Ebselen reduces autophagic activation and cell death in the ipsilateral thalamus following focal cerebral infarction.

PubMed

Li, Yiliang; Zhang, Jian; Chen, Li; Xing, Shihui; Li, Jingjing; Zhang, Yusheng; Li, Chuo; Pei, Zhong; Zeng, Jinsheng

2015-07-23

Previous studies have demonstrated that both oxidative stress and autophagy play important roles in secondary neuronal degeneration in the ipsilateral thalamus after distal middle cerebral artery occlusion (MCAO). This study aimed to investigate whether oxidative stress is associated with autophagy activation within the ipsilateral thalamus after distal MCAO. Sixty stroke-prone renovascular hypertensive rats were subjected to distal MCAO or sham operation, and were killed at 14 days after MCAO. Mn-SOD, LC3-II, Beclin-1 and p62 expression were evaluated by immunostaining and immunoblotting. Secondary damage in the thalamus was assessed with Nissl staining and immunostaining. The association of oxidative stress with autophagy activation was investigated by the antioxidant, ebselen. We found that treatment with ebselen at 24h after MCAO significantly reduced the expression of Mn-SOD in the ipsilateral thalamus at 14 days following focal cerebral infarction. In parallel, it prevented the elevation of LC3-II and Beclin-1, and the reduction of p62. Furthermore, ebselen attenuated the neuronal loss and gliosis in the ipsilateral thalamus. These results suggested that ebselen reduced oxidative stress, autophagy activation and secondary damage in the ipsilateral thalamus following MCAO. There are associations between oxidative stress, autophagy activation and secondary damage in the thalamus after MCAO. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Intracarotid amobarbital procedure: I. Prediction of decreased modality-specific memory scores after temporal lobectomy.

PubMed

Wyllie, E; Naugle, R; Awad, I; Chelune, G; Lüders, H; Dinner, D; Skibinski, C; Ahl, J

1991-01-01

To assess predictive value of the intracarotid amobarbital procedure (IAP) for decreased postoperative modality-specific memory, we studied 37 temporal lobectomy patients with intractable partial epilepsy who were selected for operation independent of preoperative IAP findings. When ipsilateral IAP failure was defined by an absolute method as a retention score less than 67%, the results were not associated with decreased modality-specific memory after operation. When ipsilateral IAP failure was defined by a comparative method as a retention score at least 20% lower after ipsilateral than contralateral injection, the results showed greater differences between groups, but differences still did not achieve statistical significance. Four left-resection patients who failed the ipsilateral IAP had a median postoperative change in the Wechsler Memory Scale-Revised (WMS-R) Verbal Memory Index score of -14%, whereas 16 left-resection patients who passed the ipsilateral IAP had a mean postoperative change in the WMS-R Verbal Memory Index score of -7.5% (p = 0.12). These results suggested that the IAP interpreted comparatively may be a helpful adjunctive test in assessment of relative risk for modality-specific memory dysfunction after temporal lobectomy, but larger series of operated patients are needed to confirm this possibility. In this series, complete amnesia was not noted after ipsilateral injection, even in patients with postoperative modality-specific memory decline.

Monaural Congenital Deafness Affects Aural Dominance and Degrades Binaural Processing

PubMed Central

Tillein, Jochen; Hubka, Peter; Kral, Andrej

2016-01-01

Cortical development extensively depends on sensory experience. Effects of congenital monaural and binaural deafness on cortical aural dominance and representation of binaural cues were investigated in the present study. We used an animal model that precisely mimics the clinical scenario of unilateral cochlear implantation in an individual with single-sided congenital deafness. Multiunit responses in cortical field A1 to cochlear implant stimulation were studied in normal-hearing cats, bilaterally congenitally deaf cats (CDCs), and unilaterally deaf cats (uCDCs). Binaural deafness reduced cortical responsiveness and decreased response thresholds and dynamic range. In contrast to CDCs, in uCDCs, cortical responsiveness was not reduced, but hemispheric-specific reorganization of aural dominance and binaural interactions were observed. Deafness led to a substantial drop in binaural facilitation in CDCs and uCDCs, demonstrating the inevitable role of experience for a binaural benefit. Sensitivity to interaural time differences was more reduced in uCDCs than in CDCs, particularly at the hemisphere ipsilateral to the hearing ear. Compared with binaural deafness, unilateral hearing prevented nonspecific reduction in cortical responsiveness, but extensively reorganized aural dominance and binaural responses. The deaf ear remained coupled with the cortex in uCDCs, demonstrating a significant difference to deprivation amblyopia in the visual system. PMID:26803166

Monaural Congenital Deafness Affects Aural Dominance and Degrades Binaural Processing.

PubMed

Tillein, Jochen; Hubka, Peter; Kral, Andrej

2016-04-01

Cortical development extensively depends on sensory experience. Effects of congenital monaural and binaural deafness on cortical aural dominance and representation of binaural cues were investigated in the present study. We used an animal model that precisely mimics the clinical scenario of unilateral cochlear implantation in an individual with single-sided congenital deafness. Multiunit responses in cortical field A1 to cochlear implant stimulation were studied in normal-hearing cats, bilaterally congenitally deaf cats (CDCs), and unilaterally deaf cats (uCDCs). Binaural deafness reduced cortical responsiveness and decreased response thresholds and dynamic range. In contrast to CDCs, in uCDCs, cortical responsiveness was not reduced, but hemispheric-specific reorganization of aural dominance and binaural interactions were observed. Deafness led to a substantial drop in binaural facilitation in CDCs and uCDCs, demonstrating the inevitable role of experience for a binaural benefit. Sensitivity to interaural time differences was more reduced in uCDCs than in CDCs, particularly at the hemisphere ipsilateral to the hearing ear. Compared with binaural deafness, unilateral hearing prevented nonspecific reduction in cortical responsiveness, but extensively reorganized aural dominance and binaural responses. The deaf ear remained coupled with the cortex in uCDCs, demonstrating a significant difference to deprivation amblyopia in the visual system. © The Author 2016. Published by Oxford University Press.

Oral 2-hydroxyoleic acid inhibits reflex hypersensitivity and open-field-induced anxiety after spared nerve injury.

PubMed

Avila-Martin, G; Galan-Arriero, I; Ferrer-Donato, A; Busquets, X; Gomez-Soriano, J; Escribá, P V; Taylor, J

2015-01-01

Recently, fatty acids have been shown to modulate sensory function in animal models of neuropathic pain. In this study, the antinociceptive effect of 2-hydroxyoleic acid (2-OHOA) was assessed following spared nerve injury (SNI) with reflex and cerebrally mediated behavioural responses. Initial antinociceptive behavioural screening of daily administration of 2-OHOA (400 mg/kg, p.o.) was assessed in Wistar rats by measuring hindlimb reflex hypersensitivity to von Frey and thermal plate stimulation up to 7 days after SNI, while its modulatory effect on lumbar spinal dorsal horn microglia reactivity was assessed with OX-42 immunohistochemistry. In vitro the effect of 2-OHOA (120 μM) on cyclooxygenase protein expression (COX-2/COX-1 ratio) in lipopolysaccharide-activated macrophage cells was tested with Western blot analysis. Finally, the effects of 2-OHOA treatment on the place escape aversion paradigm (PEAP) and the open-field-induced anxiety test were tested at 21 days following nerve injury compared with vehicle-treated sham and pregabalin-SNI (30 mg/kg, p.o.) control groups. Oral 2-OHOA significantly reduced ipsilateral mechanical and thermal hypersensitivity up to 7 days after SNI. Additionally 2-OHOA decreased the COX-2/COX-1 ratio in lipopolysaccharide-activated macrophage cells and OX-42 expression within the ipsilateral lumbar spinal dorsal horn 7 days after SNI. 2-OHOA significantly restored inner-zone exploration in the open-field test compared with the vehicle-treated sham group at 21 days after SNI. Oral administration of the modified omega 9 fatty acid, 2-OHOA, mediates antinociception and prevents open-field-induced anxiety in the SNI model in Wistar rats, which is mediated by an inhibition of spinal dorsal horn microglia activation. © 2014 European Pain Federation - EFIC®

Re-evaluation of Ipsilateral Radiation for T1-T2N0-N2b Tonsil Carcinoma at the Princess Margaret Hospital in the Human Papillomavirus Era, 25 Years Later

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Shao Hui, E-mail: shaohui.huang@rmp.uhn.on.ca; Waldron, John; Department of Otolaryngology—Head & Neck Surgery, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario

Purpose: To report the outcome of ipsilateral radiation therapy (RT) in human papillomavirus (HPV)-positive (HPV+) patients and HPV-negative (HPV−) patients with T1-T2N0-N2b tonsillar cancer treated 25 years after our initial historical cohort. Methods and Materials: Patients with T1-T2N0-N2b tonsillar cancer who received ipsilateral RT or bilateral RT between 1999 and 2014 were reviewed. Overall survival (OS), local control (LC), regional control (RC), and grade 3 to 4 late toxicity (LT) were compared between ipsilateral RT and bilateral RT within HPV+ and HPV− patients, separately. Results: HPV status was ascertained in 379/427 (88%) consecutive patients (ipsilateral RT: 62 HPV+, 34 HPV−; bilateralmore » RT: 240 HPV+ 240, 41 HPV−). The proportion of ipsilateral RT by N category for HPV+ and HPV− patients were as follows: N0: 24/37 (65%) versus 28/48 (74%); N1: 21/49 (43%) versus 4/9 (44%); N2a: 10/39 (26%) versus 1/4 (25%); and N2b: 7/177 (4%) versus 1/24 (4%), respectively. Of the patients receiving ipsilateral RT, 94/96 (98%) were treated with RT alone. The median follow-up time was 5.03 years. The respective 5-year rates of OS, LC, RC, and LT were similar between ipsilateral RT and bilateral RT for the HPV+ patients (OS: 89% vs 87%, P=.55; LC: 97% vs 98%, P=.65; RC: 98% vs 97%, P=.27; LT: 17% vs 12%, P=.83) and HPV− patients (OS: 63% vs 48%, P=.27; LC: 90% vs 80%, P=.19; RC: 94% vs 83%, P=.14; LT: 15% vs 22%, P=.36). Of the 96 patients receiving ipsilateral RT, contralateral neck failure (CNF) occurred in 1/52 HPV+ patients and 1/34 HPV− patients. The 5-year CNF rates were 2% (95% CI: 1-9) (HPV+: 2% [0-14]; HPV−: 3% [0-21], P=.66). Five local failures (2 HPV+; 3 HPV−) and no distant failures were seen. The 5-year rates of LC, RC, and LT were 97% versus 90% (P=.24), 98% versus 94% (P=.25), and 18% versus 15% (P=.75) for the HPV+ and HPV− cohorts, respectively. Osteoradionecrosis occurred in 9 patients: 6/47 (13%) treated with conventional RT and 3/49 (6%) with intensity modulated RT (P=.32). Conclusion: Ipsilateral radiation to selected patients with T1-T2N0-N2b tonsillar cancer results in equally excellent outcomes regardless of tumor HPV status.« less

Comparative study on the analgesic effect of acute ipsilateral shoulder pain after open thoracotomy between preoperative ultrasound guided suprascapular nerve block (SNB) and intraoperative phrenic nerve infiltration (PNI) in cancer lung patients.

PubMed

Elfokery, Bassel M; Tawfic, Sahar A; Abdelrahman, Abdelrahman M; Abbas, Dina N; Abdelghaffar, Ikramy M

2018-03-01

Acute ipsilateral shoulder pain (ISP) is a common complaint in patients after thoracotomy. The incidence ranges from 21% to 97%. Unfortunately, clinical studies did not put enough focus on ISP post thoracic surgery. This study was designed to compare the effectiveness of suprascapular nerve block (SNB) and phrenic nerve infiltration (PNI) for controlling ISP. One hundred and thirty-five lung cancer patients (135) scheduled for open-lung surgery were randomly allocated into three equal groups; control group: received thoracic epidural with general anesthesia, suprascapular group: (SNB) one hour before the operation with 10 ml bupivacaine plus thoracic epidural with general anesthesia and phrenic nerve group: (PNI) was performed by the operating surgeon with 10 ml bupivacaine plus thoracic epidural with general anesthesia. The visual analogue score (VAS) of ISP, rescue of ketorolac for break through shoulder pain, peak expiratory flow rate (PEFR) and arterial blood gases were measured every 6 h postoperatively for 48 h. The VAS, rescue doses of ketorolc and PEFR were significantly lower in the phrenic nerve group (P-value <0.05). There was no statistically significant difference between the three groups postoperatively as regards arterial blood gases (P-value >0.05). PNI is more effective than SNB for ISP. Production and hosting by Elsevier B.V.

Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection.

PubMed

Li, Yi-Ke; Yang, Juan-Mei; Huang, Yi-Bo; Ren, Dong-Dong; Chi, Fang-Lu

2015-06-01

The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection + lingual nerve transection. Rats were allowed up to 42 days of recovery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantified and compared among groups. No significant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection + lingual nerve transection groups. Taste bud counts, volumes and taste receptor cell numbers on the ipsilateral side all decreased significantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

The neural correlates of learned motor acuity

PubMed Central

Yang, Juemin; Caffo, Brian; Mazzoni, Pietro; Krakauer, John W.

2014-01-01

We recently defined a component of motor skill learning as “motor acuity,” quantified as a shift in the speed-accuracy trade-off function for a task. These shifts are primarily driven by reductions in movement variability. To determine the neural correlates of improvement in motor acuity, we devised a motor task compatible with magnetic resonance brain imaging that required subjects to make finely controlled wrist movements under visual guidance. Subjects were imaged on day 1 and day 5 while they performed this task and were trained outside the scanner on intervening days 2, 3, and 4. The potential confound of performance changes between days 1 and 5 was avoided by constraining movement time to a fixed duration. After training, subjects showed a marked increase in success rate and a reduction in trial-by-trial variability for the trained task but not for an untrained control task, without changes in mean trajectory. The decrease in variability for the trained task was associated with increased activation in contralateral primary motor and premotor cortical areas and in ipsilateral cerebellum. A global nonlocalizing multivariate analysis confirmed that learning was associated with increased overall brain activation. We suggest that motor acuity is acquired through increases in the number of neurons recruited in contralateral motor cortical areas and in ipsilateral cerebellum, which could reflect increased signal-to-noise ratio in motor output and improved state estimation for feedback corrections, respectively. PMID:24848466

Modulation of early cortical processing during divided attention to non-contiguous locations.

PubMed

Frey, Hans-Peter; Schmid, Anita M; Murphy, Jeremy W; Molholm, Sophie; Lalor, Edmund C; Foxe, John J

2014-05-01

We often face the challenge of simultaneously attending to multiple non-contiguous regions of space. There is ongoing debate as to how spatial attention is divided under these situations. Whereas, for several years, the predominant view was that humans could divide the attentional spotlight, several recent studies argue in favor of a unitary spotlight that rhythmically samples relevant locations. Here, this issue was addressed by the use of high-density electrophysiology in concert with the multifocal m-sequence technique to examine visual evoked responses to multiple simultaneous streams of stimulation. Concurrently, we assayed the topographic distribution of alpha-band oscillatory mechanisms, a measure of attentional suppression. Participants performed a difficult detection task that required simultaneous attention to two stimuli in contiguous (undivided) or non-contiguous parts of space. In the undivided condition, the classic pattern of attentional modulation was observed, with increased amplitude of the early visual evoked response and increased alpha amplitude ipsilateral to the attended hemifield. For the divided condition, early visual responses to attended stimuli were also enhanced, and the observed multifocal topographic distribution of alpha suppression was in line with the divided attention hypothesis. These results support the existence of divided attentional spotlights, providing evidence that the corresponding modulation occurs during initial sensory processing time-frames in hierarchically early visual regions, and that suppressive mechanisms of visual attention selectively target distracter locations during divided spatial attention. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Ipsilateral EEG mu rhythm reflects the excitability of uncrossed pathways projecting to shoulder muscles.

PubMed

Hasegawa, Keita; Kasuga, Shoko; Takasaki, Kenichi; Mizuno, Katsuhiro; Liu, Meigen; Ushiba, Junichi

2017-08-25

Motor planning, imagery or execution is associated with event-related desynchronization (ERD) of mu rhythm oscillations (8-13 Hz) recordable over sensorimotor areas using electroencephalography (EEG). It was shown that motor imagery involving distal muscles, e.g. finger movements, results in contralateral ERD correlating with increased excitability of the contralateral corticospinal tract (c-CST). Following the rationale that purposefully increasing c-CST excitability might facilitate motor recovery after stroke, ERD recently became an attractive target for brain-computer interface (BCI)-based neurorehabilitation training. It was unclear, however, whether ERD would also reflect excitability of the ipsilateral corticospinal tract (i-CST) that mainly innervates proximal muscles involved in e.g. shoulder movements. Such knowledge would be important to optimize and extend ERD-based BCI neurorehabilitation protocols, e.g. to restore shoulder movements after stroke. Here we used single-pulse transcranial magnetic stimulation (TMS) targeting the ipsilateral primary motor cortex to elicit motor evoked potentials (MEPs) of the trapezius muscle. To assess whether ERD reflects excitability of the i-CST, a correlation analysis between between MEP amplitudes and ipsilateral ERD was performed. Experiment 1 consisted of a motor execution task during which 10 healthy volunteers performed elevations of the shoulder girdle or finger pinching while a 128-channel EEG was recorded. Experiment 2 consisted of a motor imagery task during which 16 healthy volunteers imagined shoulder girdle elevations or finger pinching while an EEG was recorded; the participants simultaneously received randomly timed, single-pulse TMS to the ipsilateral primary motor cortex. The spatial pattern and amplitude of ERD and the amplitude of the agonist muscle's TMS-induced MEPs were analyzed. ERDs occurred bilaterally during both execution and imagery of shoulder girdle elevations, but were lateralized to the contralateral hemisphere during finger pinching. We found that trapezius MEPs increased during motor imagery of shoulder elevations and correlated with ipsilateral ERD amplitudes. Ipsilateral ERD during execution and imagery of shoulder girdle elevations appears to reflect the excitability of uncrossed pathways projecting to the shoulder muscles. As such, ipsilateral ERD could be used for neurofeedback training of shoulder movement, aiming at reanimation of the i-CST.

Association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury after intensity-modulated radiotherapy in lung cancer: a retrospective analysis.

PubMed

Chen, Jinmei; Hong, Jinsheng; Zou, Xi; Lv, Wenlong; Guo, Feibao; Hong, Hualan; Zhang, Weijian

2015-11-01

The aim of this study was to investigate the association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury (RILI) after intensity-modulated radiotherapy (IMRT) for lung cancer. The normal lung relative volumes receiving greater than 5, 10, 20 and 30 Gy (V5-30) mean lung dose (MLD), and absolute volumes spared from greater than 5, 10, 20 and 30 Gy (AVS5-30) for the bilateral and ipsilateral lungs of 83 patients were recorded. Any association of clinical factors and dose-volume parameters with Grade ≥2 RILI was analyzed. The median follow-up was 12.3 months; 18 (21.7%) cases of Grade 2 RILI, seven (8.4%) of Grade 3 and two (2.4%) of Grade 4 were observed. Univariate analysis revealed the located lobe of the primary tumor. V5, V10, V20, MLD of the ipsilateral lung, V5, V10, V20, V30 and MLD of the bilateral lung, and AVS5 and AVS10 of the ipsilateral lung were associated with Grade ≥2 RILI (P < 0.05). Multivariate analysis indicated AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI (P = 0.010, OR = 0.272, 95% CI: 0.102-0.729). Receiver operating characteristic curves indicated Grade ≥2 RILI could be predicted using AVS5 of the ipsilateral lung (area under curve, 0.668; cutoff value, 564.9 cm(3); sensitivity, 60.7%; specificity, 70.4%). The incidence of Grade ≥2 RILI was significantly lower with AVS5 of the ipsilateral lung ≥564.9 cm(3) than with AVS5 < 564.9 cm(3) (P = 0.008). Low-dose irradiation relative volumes and MLD of the bilateral or ipsilateral lung were associated with Grade ≥2 RILI, and AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI for lung cancer after IMRT. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Effects of subjective preference of colors on attention-related occipital theta oscillations.

PubMed

Kawasaki, Masahiro; Yamaguchi, Yoko

2012-01-02

Human daily behaviors are often affected by subjective preferences. Studies have shown that physical responses are affected by unconscious preferences before conscious decision making. Accordingly, attention-related neural activities could be influenced by unconscious preferences. However, few neurological data exist on the relationship between visual attention and subjective preference. To address this issue, we focused on lateralization during visual attention and investigated the effects of subjective color preferences on visual attention-related brain activities. We recorded electroencephalograph (EEG) data during a preference judgment task that required 19 participants to choose their preferred color from 2 colors simultaneously presented to the right and left hemifields. In addition, to identify oscillatory activity during visual attention, we conducted a control experiment in which the participants focused on either the right or the left color without stating their preference. The EEG results showed enhanced theta (4-6 Hz) and decreased alpha (10-12 Hz) activities in the right and left occipital electrodes when the participants focused on the color in the opposite hemifield. Occipital theta synchronizations also increased contralaterally to the hemifield to which the preferred color was presented, whereas the alpha desynchronizations showed no lateralization. The contralateral occipital theta activity lasted longer than the ipsilateral occipital theta activity. Interestingly, theta lateralization was observed even when the preferred color was presented to the unattended side in the control experiment, revealing the strength of the preference-related theta-modulation effect irrespective of visual attention. These results indicate that subjective preferences modulate visual attention-related brain activities. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

Computer-assisted kinematic evaluation of induced compensatory movements resembling lameness in horses trotting on a treadmill.

PubMed

Kelmer, Gal; Keegan, Kevin G; Kramer, Joanne; Wilson, David A; Pai, Frank P; Singh, Prableen

2005-04-01

To characterize compensatory movements of the head and pelvis that resemble lameness in horses. 17 adult horses. Kinematic evaluations were performed while horses trotted on a treadmill before and after shoe-induced lameness. Lameness was quantified and the affected limb determined by algorithms that measured asymmetry in vertical movement of the head and pelvis. Induced primary lameness and compensatory movements resembling lameness were assessed by the Friedman test. Association between induced lameness and compensatory movements was examined by regression analysis. Compensatory movements resembling lameness in the ipsilateral forelimb were seen with induced lameness of a hind limb. There was less downward and less upward head movement during and after the stance phase of the ipsilateral forelimb. Doubling the severity of lameness in the hind limb increased severity of the compensatory movements in the ipsilateral forelimb by 50%. Compensatory movements resembling lameness of the hind limb were seen after induced lameness in a forelimb. There was less upward movement of the pelvis after the stance phase of the contralateral hind limb and, to a lesser extent, less downward movement of the pelvis during the stance phase of the ipsilateral hind limb. Doubling the severity of lameness in the forelimb increased compensatory movements of the contralateral hind limb by 5%. Induced lameness in a hind limb causes prominent compensatory movements resembling lameness in the ipsilateral forelimb. Induced lameness in a forelimb causes slight compensatory movements resembling lameness in the ipsilateral and contralateral hind limbs.

Neurogenesis and angiogenesis within the ipsilateral thalamus with secondary damage after focal cortical infarction in hypertensive rats.

PubMed

Ling, Li; Zeng, Jinsheng; Pei, Zhong; Cheung, Raymond T F; Hou, Qinghua; Xing, Shihui; Zhang, Suping

2009-09-01

Neurogenesis and angiogenesis in the subventricular zone and peri-infarct region have been confirmed. However, newly formed neuronal cells and blood vessels that appear in the nonischemic ipsilateral ventroposterior nucleus (VPN) of the thalamus with secondary damage after stroke has not been previously studied. Twenty-four stroke-prone renovascular hypertensive rats were subjected to distal right middle cerebral artery occlusion (MCAO) or sham operation. 5'-Bromo-2'-deoxyuridine (BrdU) was used to label cell proliferation. Rats were killed at 7 or 14 days after the operation. Neuronal nuclei (NeuN), OX-42, BrdU, nestin, laminin(+), BrdU(+)/nestin(+), BrdU(+)/NeuN(+), nestin(+)/GFAP(+)(glial fibrillary acidic protein), and BrdU(+)/laminin(+) immunoreactive cells were detected within the ipsilateral VPN. The primary infarction was confined to the right somatosensory cortex. Within the ipsilateral VPN of the ischemic rats, the number of NeuN(+) neurons decreased, the OX-42(+) microglia cells were activated, and BrdU(+) and nestin(+) cells were detected at day 7 after MCAO and increased in number at day 14. Moreover, BrdU(+)/nestin(+) cells and BrdU(+)/NeuN(+) cells were detected at day 14 after MCAO. In addition, the ischemic rats showed a significant increase in vascular density in the ipsilateral VPN compared with the sham-operated rats. These results suggest that secondary damage with neurogenesis and angiogenesis of the ipsilateral VPN of the thalamus occurs after focal cortical infarction.

Motor demand-dependent activation of ipsilateral motor cortex.

PubMed

Buetefisch, Cathrin M; Revill, Kate Pirog; Shuster, Linda; Hines, Benjamin; Parsons, Michael

2014-08-15

The role of ipsilateral primary motor cortex (M1) in hand motor control during complex task performance remains controversial. Bilateral M1 activation is inconsistently observed in functional (f)MRI studies of unilateral hand performance. Two factors limit the interpretation of these data. As the motor tasks differ qualitatively in these studies, it is conceivable that M1 contributions differ with the demand on skillfulness. Second, most studies lack the verification of a strictly unilateral execution of the motor task during the acquisition of imaging data. Here, we use fMRI to determine whether ipsilateral M1 activity depends on the demand for precision in a pointing task where precision varied quantitatively while movement trajectories remained equal. Thirteen healthy participants used an MRI-compatible joystick to point to targets of four different sizes in a block design. A clustered acquisition technique allowed simultaneous fMRI/EMG data collection and confirmed that movements were strictly unilateral. Accuracy of performance increased with target size. Overall, the pointing task revealed activation in contralateral and ipsilateral M1, extending into contralateral somatosensory and parietal areas. Target size-dependent activation differences were found in ipsilateral M1 extending into the temporal/parietal junction, where activation increased with increasing demand on accuracy. The results suggest that ipsilateral M1 is active during the execution of a unilateral motor task and that its activity is modulated by the demand on precision. Copyright © 2014 the American Physiological Society.

Note: Unshielded bilateral magnetoencephalography system using two-dimensional gradiometers

NASA Astrophysics Data System (ADS)

Seki, Yusuke; Kandori, Akihiko; Ogata, Kuniomi; Miyashita, Tsuyoshi; Kumagai, Yukio; Ohnuma, Mitsuru; Konaka, Kuni; Naritomi, Hiroaki

2010-09-01

Magnetoencephalography (MEG) noninvasively measures neuronal activity with high temporal resolution. The aim of this study was to develop a new type of MEG system that can measure bilateral MEG waveforms without a magnetically shielded room, which is an obstacle to reducing both the cost and size of an MEG system. An unshielded bilateral MEG system was developed using four two-dimensional (2D) gradiometers and two symmetric cryostats. The 2D gradiometer, which is based on a low-Tc superconducting quantum interference device and wire-wound pickup coil detects a magnetic-field gradient in two orthogonal directions, or ∂/∂x(∂2Bz/∂z2), and reduces environmental magnetic-field noise by more than 50 dB. The cryostats can be symmetrically positioned in three directions: vertical, horizontal, and rotational. This makes it possible to detect bilateral neuronal activity in the cerebral cortex simultaneously. Bilateral auditory-evoked fields (AEF) of 18 elderly subjects were measured in an unshielded hospital environment using the MEG system. As a result, both the ipsilateral and the contralateral AEF component N100m, which is the magnetic counterpart of electric N100 in electroencephalography and appears about 100 ms after the onset of an auditory stimulus, were successfully detected for all the subjects. Moreover, the ipsilateral P50m and the contralateral P50m were also detected for 12 (67%) and 16 (89%) subjects, respectively. Experimental results demonstrate that the unshielded bilateral MEG system can detect MEG waveforms, which are associated with brain dysfunction such as epilepsy, Alzheimer's disease, and Down syndrome.

Unilateral hearing during development: hemispheric specificity in plastic reorganizations

PubMed Central

Kral, Andrej; Heid, Silvia; Hubka, Peter; Tillein, Jochen

2013-01-01

The present study investigates the hemispheric contributions of neuronal reorganization following early single-sided hearing (unilateral deafness). The experiments were performed on ten cats from our colony of deaf white cats. Two were identified in early hearing screening as unilaterally congenitally deaf. The remaining eight were bilaterally congenitally deaf, unilaterally implanted at different ages with a cochlear implant. Implanted animals were chronically stimulated using a single-channel portable signal processor for two to five months. Microelectrode recordings were performed at the primary auditory cortex under stimulation at the hearing and deaf ear with bilateral cochlear implants. Local field potentials (LFPs) were compared at the cortex ipsilateral and contralateral to the hearing ear. The focus of the study was on the morphology and the onset latency of the LFPs. With respect to morphology of LFPs, pronounced hemisphere-specific effects were observed. Morphology of amplitude-normalized LFPs for stimulation of the deaf and the hearing ear was similar for responses recorded at the same hemisphere. However, when comparisons were performed between the hemispheres, the morphology was more dissimilar even though the same ear was stimulated. This demonstrates hemispheric specificity of some cortical adaptations irrespective of the ear stimulated. The results suggest a specific adaptation process at the hemisphere ipsilateral to the hearing ear, involving specific (down-regulated inhibitory) mechanisms not found in the contralateral hemisphere. Finally, onset latencies revealed that the sensitive period for the cortex ipsilateral to the hearing ear is shorter than that for the contralateral cortex. Unilateral hearing experience leads to a functionally-asymmetric brain with different neuronal reorganizations and different sensitive periods involved. PMID:24348345

Unilateral hearing during development: hemispheric specificity in plastic reorganizations.

PubMed

Kral, Andrej; Heid, Silvia; Hubka, Peter; Tillein, Jochen

2013-01-01

The present study investigates the hemispheric contributions of neuronal reorganization following early single-sided hearing (unilateral deafness). The experiments were performed on ten cats from our colony of deaf white cats. Two were identified in early hearing screening as unilaterally congenitally deaf. The remaining eight were bilaterally congenitally deaf, unilaterally implanted at different ages with a cochlear implant. Implanted animals were chronically stimulated using a single-channel portable signal processor for two to five months. Microelectrode recordings were performed at the primary auditory cortex under stimulation at the hearing and deaf ear with bilateral cochlear implants. Local field potentials (LFPs) were compared at the cortex ipsilateral and contralateral to the hearing ear. The focus of the study was on the morphology and the onset latency of the LFPs. With respect to morphology of LFPs, pronounced hemisphere-specific effects were observed. Morphology of amplitude-normalized LFPs for stimulation of the deaf and the hearing ear was similar for responses recorded at the same hemisphere. However, when comparisons were performed between the hemispheres, the morphology was more dissimilar even though the same ear was stimulated. This demonstrates hemispheric specificity of some cortical adaptations irrespective of the ear stimulated. The results suggest a specific adaptation process at the hemisphere ipsilateral to the hearing ear, involving specific (down-regulated inhibitory) mechanisms not found in the contralateral hemisphere. Finally, onset latencies revealed that the sensitive period for the cortex ipsilateral to the hearing ear is shorter than that for the contralateral cortex. Unilateral hearing experience leads to a functionally-asymmetric brain with different neuronal reorganizations and different sensitive periods involved.

Early segregation of layered projections from the lateral superior olivary nucleusto the central nucleus of the inferior colliculus in the neonatal cat

PubMed Central

Gabriele, Mark L.; Shahmoradian, Sarah H.; French, Christopher C.; Henkel, Craig K.we; McHaffie, John G.

2007-01-01

The central nucleus of the inferior colliculus (IC) is a laminated structure that receives multiple converging afferent projections. These projections terminate in a layered arrangement and are aligned with dendritic arbors of the predominant disc-shaped neurons, forming fibrodendritic laminae. Within this structural framework, inputs terminate in a precise manner, establishing a mosaic of partially overlapping domains that likely define functional compartments. Although several of these patterned inputs have been described in the adult, relatively little is known about their organization prior to hearing onset. The present study used the lipophilic carbocyanine dyes DiI and DiD to examine the ipsilateral and contralateral projections from the lateral superior olivary (LSO) nucleus to the IC in a developmental series of paraformaldehyde-fixed kitten tissue. By birth, the crossed and uncrossed projections had reached the IC and were distributed across the frequency axis of the central nucleus. At this earliest postnatal stage, projections already exhibited a characteristic banded arrangement similar to that described in the adult. The heaviest terminal fields of the two inputs were always complementary in nature, with the ipsilateral input appearing slightly denser. This early arrangement of interdigitating ipsilateral and contralateral LSO axonal bands that occupy adjacent sublayers supports the idea that the initial establishment of this highly organized mosaic of inputs that defines distinct synaptic domains within the IC occurs largely in the absence of auditory experience. Potential developmental mechanisms that may shape these highly ordered inputs prior to hearing onset are discussed. PMID:17850770

Principles of ipsilateral and contralateral cortico-cortical connectivity in the mouse.

PubMed

Goulas, Alexandros; Uylings, Harry B M; Hilgetag, Claus C

2017-04-01

Structural connectivity among cortical areas provides the substrate for information exchange in the cerebral cortex and is characterized by systematic patterns of presence or absence of connections. What principles govern this cortical wiring diagram? Here, we investigate the relation of physical distance and cytoarchitecture with the connectional architecture of the mouse cortex. Moreover, we examine the relation between patterns of ipsilateral and contralateral connections. Our analysis reveals a mirrored and attenuated organization of contralateral connections when compared with ipsilateral connections. Both physical distance and cytoarchitectonic similarity of cortical areas are related to the presence or absence of connections. Notably, our analysis demonstrates that the combination of these factors relates better to cortico-cortical connectivity than each factor in isolation and that the two factors relate differently to ipsilateral and contralateral connectivity. Physical distance is more tightly related to the presence or absence of ipsilateral connections, but its relevance greatly diminishes for contralateral connections, while the contribution of cytoarchitectonic similarity remains relatively stable. Our results, together with similar findings in the cat and macaque cortex, suggest that a common set of principles underlies the macroscale wiring of the mammalian cerebral cortex.

Decision-making for complex scapula and ipsilateral clavicle fractures: a review.

PubMed

Hess, Florian; Zettl, Ralph; Smolen, Daniel; Knoth, Christoph

2018-03-23

Complex scapula with ipsilateral clavicle fracures remains a challange and treatment recommendations are still missing.  This review provides an overview of the evolution of the definition, classification and treatment strategies for complex scapula and ipsilateral clavicle fractures. As with other rare conditions, consensus has not been reached on the most suitable management strategies to treat these patients. The aim of this review is twofold: to compile and summarize the currently available literature on this topic, and to recommend treatment approaches. Included in the review are the following topics: biomechanics of scapula and ipsilateral clavicle fractures, preoperative radiological evaluation, surgical treatment of the clavicle only, surgical treatment of both the clavicle and scapula, and nonsurgical treatment options. A decision-making algorithm is proposed for different treatment strategies based on pre-operative parameters, and an example of a case treated our institution is presented to illustrate use of the algorithm. The role of instability in complex scapula with ipsilateral clavicle fractures remains unclear. The question of stability is preoperatively less relevant than the question of whether the dislocated fragments lead to compromised shoulder function.

Novel magnetomechanical MR compatible vibrational device for producing kinesthetic illusion during fMRI.

PubMed

Carr, Sarah J; Borreggine, Kristin; Heilman, Jeremiah; Griswold, Mark; Walter, Benjamin L

2013-11-01

Functional MRI (fMRI) can provide insights into the functioning of the sensorimotor system, which is of particular interest in studying people with movement disorders or chronic pain conditions. This creates a demand for manipulanda that can fit and operate within the environment of a MRI scanner. Here, the authors present a magnetomechanical device that delivers a vibrotactile sensation to the skin with a force of approximately 9 N. MRI compatibility of the device was tested in a 3 T scanner using a phantom to simulate the head. Preliminary investigation into the effectiveness of the device at producing cortical and subcortical activity was also conducted with a group of seven healthy subjects. The vibration was applied to the right extensor carpi ulnaris tendon to induce a kinesthetic illusion of flexion and extension of the wrist. The MRI compatibility tests showed the device did not produce image artifacts and the generated electromagnetic field did not disrupt the static magnetic field of the scanner or its operation. The subject group results showed activity in the contralateral putamen, premotor cortex, and dorsal lateral prefrontal cortex. Ipsilaterally, there was increased activity in the superior and inferior parietal lobules. Areas that activated bilaterally included the thalamus, anterior cingulate, secondary somatosensory areas (S2), temporal lobes, and visual association areas. This device offers an effective tool with precise control over the vibratory stimulus, delivering higher forces than some other types of devices (e.g., piezoelectric actuators). It can be useful for investigating sensory systems and sensorimotor integration.

[Clinico-statistical study on availability of Esterman disability score for assessment of mobility difficulty in patients with visual field loss].

PubMed

Yamagata, Yoshitaka; Terada, Yuko; Suzuki, Atsushi; Mimura, Osamu

2010-01-01

The visual efficiency scale currently adopted to determine the legal grade of visual disability associated with visual field loss in Japan is not appropriate for the evaluation of disability regarding daily living activities. We investigated whether Esterman disability score (EDS) is suitable for the assessment of mobility difficulty in patients with visual field loss. The correlation between the EDS calculated from Goldmann's kinetic visual field and the degree of subjective mobility difficulty determined by a questionnaire was investigated in 164 patients with visual field loss. The correlation between the EDS determined using a program built into the Humphrey field analyzer and that calculated from Goldmann's kinetic visual field was also investigated. The EDS based on the kinetic visual field was correlated well with the degree of subjective mobility difficulty, and the EDS measured using the Humphrey field analyzer could be estimated from the kinetic visual field-based EDS. Instead of the currently adopted visual efficiency scale, EDS should be employed for the assessment of mobility difficulty in patients with visual field loss, also to establish new judgment criteria concerning the visual field.

Decrease of tight junction integrity in the ipsilateral thalamus during the acute stage after focal infarction and ablation of the cerebral cortex in rats.

PubMed

Li, Jing-Jing; Xing, Shi-Hui; Zhang, Jian; Hong, Hua; Li, Yi-Liang; Dang, Chao; Zhang, Yu-Sheng; Li, Chuo; Fan, Yu-Hua; Yu, Jian; Pei, Zhong; Zeng, Jin-Sheng

2011-11-01

1. Whether damage to the blood-brain barrier (BBB) occurs in remote areas after a focal cortical lesion remains unknown. The present study investigated tight junction-related proteins and tight junction microstructure in the ipsilateral thalamus during the acute stage after middle cerebral artery occlusion (MCAO) and cortical aspiration lesion (CAL) in rats. 2. Thirty-six hypertensive and normotensive rats were subjected to MCAO or CAL; another 18 rats in each group were submitted to sham operation. Zonula Occluden (ZO)-1, occludin and albumin were detected by western blotting 12 and 24 h after surgery. Tight junction microstructure was evaluated using electron microscopy, whereas albumin location in the ipsilateral thalamus was determined using double immunostaining for albumin and occludin or albumin and neuronal nuclei (NeuN) 24 h after surgery. 3. Twenty-four hours after MCAO or CAL, occludin expression was reduced to 78.4% and 81.3%, respectively, compared with control. A reduction in ZO-1 expression in the ipsilateral thalamus (to 79%) was seen only after CAL (P < 0.05). Membrane contact at the tight junction was discontinuous in the ipsilateral thalamus in both MCAO and CAL rats. Albumin levels were 23.2% and 82.5% higher in the ipsilateral thalamus after MCAO and CAL, respectively (P < 0.05). The percentage of the albumin-positive area that coincided with the occludin-positive area in the MCAO and CAL groups was 76.8% and 64.6%, respectively, indicating that albumin was mainly localized around the microvessels. 4. The results of the present study suggest that tight junction integrity decreases during the acute stage in the ipsilateral thalamus after MCAO and CAL in rats. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters.

PubMed

Sun, Wenzhao; Wang, Bin; Qiu, Bo; Liang, Jian; Xie, Weihao; Deng, Xiaowu; Qi, Zhenyu

2017-03-21

To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated. The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised. Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification.

Case report: AVN of the femoral head five year follow-up of the combination of ipsilateral femoral neck and sub-trochanteric fracture.

PubMed

Zhang, Wei; Zhu, Feng; Dong, Hanqing; Xu, Yaozeng

2016-04-01

To our knowledge, the type of combination of ipsilateral femoral neck and sub-trochanteric fracture is rare. And the long term follow-up is seldom been reported. A 60 year old woman suffered from a traffic accident. We gave her the intramedullary nail treatment for the combination of ipsilateral femoral neck and sub-trochanteric fracture, and the fracture indeed cured after one year and there is no clue of necrosis of the femoral head, but after 5 years, there is an evidence of necrosis of the femoral head. Combination of ipsilateral femoral neck and sub-trochanteric fracture should be kept in mind. Patients with this unusual fracture should be kept under surveillance for longer than might be thought currently to be necessary for there is a possibility of necrosis of the femoral head, even a nondisplaced femoral neck fracture.

SU-E-T-632: A Dosimetric Comparison of the 3D-CRT Planning of Chest Wall in Post-Mastectomy Breast Cancer Patients, with and Without Breast Board Setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muzaffar, Ambreen; Masood, Asif; Ullah, Haseeb

2014-06-15

Purpose: Breast boards are used in breast radiation which increases normal lung and heart doses, when supraclavicular field is included. Therefore, in this study through dose volume histogram (DVHs), lung and heart doses comparison was done between two different setups i.e. with and without breast board, for the treatment of left chest wall and supraclavicular fossa in postmastectomy left breast cancer. Methods: In this study, CT-Simulation scans of ten breast cancer patients were done with and without breast board, at Shifa International Hospitals Islamabad, to investigate the differences between the two different setups of the irradiation of left chest wallmore » in terms of lung and heart doses. For immobilization, support under the neck, shoulders and arms was used. Precise PLAN 2.15 treatment planning system (TPS) was used for 3D-CRT planning. The total prescribed dose for both the plans was 5000 cGy/25 fractions. The chest wall was treated with a pair of tangential photon fields and the upper supraclavicular nodal regions were treated with an anterior photon field. A mono-isocentric technique was used to match the tangential fields with the anterior field at the isocentre. The dose volume histogram was used to compare the doses of heart and ipsilateral lung. Results: Both the plans of each patient were generated and compared. DVH results showed that for the same PTV dose coverage, plans without breast board resulted in a reduction of lung and heart doses compared with the plans with breast board. There was significant reductions in V20, V<25 and mean doses for lung and V<9 and mean doses for heart. Conclusion: In comparison of both the plans, setup without breast board significantly reduced the dose-volume of the ipsilateral lung and heart in left chest wall patients. Waived registration request has been submitted.« less

An anatomical analysis of the mini-modified orbitozygomatic and supra-orbital approaches.

PubMed

Figueiredo, Eberval G; Deshmukh, Puspha; Nakaji, Peter; Shu, Edson Bor Seng; Crawford, Neil; Spetzler, Robert F; Preul, Mark C

2012-11-01

Seven sides of cadaver heads were used to compare the surgical exposures provided by the mini-modified orbitozygomatic (MOz) and supra-orbital (SO) approaches. The Optotrak 3020 computerized tracking system (Northern Digital, Waterloo, ON, Canada) was utilized to evaluate the area of anatomical exposure defined by six points: (1) ipsilateral sphenoid ridge; (2) most distal point of the ipsilateral middle cerebral artery (MCA); (3) most distal point of the ipsilateral posterior cerebral artery (PCA); (4) most distal point of the contralateral PCA; (5) most distal point of the contralateral MCA; and (6) contralateral sphenoid ridge. Additionally, angles of approach for the ipsilateral MCA bifurcation, ipsilateral ICA bifurcation, basilar artery tip, contralateral MCA and ICA bifurcation and anterior communicating artery (AcomA) were evaluated, first for SO and then for MOz. An image guidance system was used to evaluate the limits of surgical exposure. No differences in the area of surgical exposure were noted (p>0.05). Vertical angles were significantly wider for the ipsilateral and contralateral ICA bifurcation, AcomA, contralateral MCA and basilar tip (p<0.05) for MOz. No differences in horizontal angles were observed between the approaches for the six targets (p>0.05). There were no differences in the limits of exposure. MOz affords no additional surgical working space. However, our results demonstrate systematically that vertical exposure is improved. The MOz should be performed while planning an approach to these regions and a wider exposure in the vertical axis is needed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Bepridil decreases Aβ and calcium levels in the thalamus after middle cerebral artery occlusion in rats

PubMed Central

Sarajärvi, Timo; Lipsanen, Anu; Mäkinen, Petra; Peräniemi, Sirpa; Soininen, Hilkka; Haapasalo, Annakaisa; Jolkkonen, Jukka; Hiltunen, Mikko

2012-01-01

Alzheimer's disease (AD) and cerebral ischaemia share similar features in terms of altered amyloid precursor protein (APP) processing and β-amyloid (Aβ) accumulation. We have previously shown that Aβ and calcium deposition, and β-secretase activity, are robustly increased in the ipsilateral thalamus after transient middle cerebral artery occlusion (MCAO) in rats. Here, we investigated whether the non-selective calcium channel blocker bepridil, which also inhibits β-secretase cleavage of APP, affects thalamic accumulation of Aβ and calcium and in turn influences functional recovery in rats subjected to MCAO. A 27-day bepridil treatment (50 mg/kg, p.o.) initiated 2 days after MCAO significantly decreased the levels of soluble Aβ40, Aβ42 and calcium in the ipsilateral thalamus, as compared with vehicle-treated MCAO rats. Expression of seladin-1/DHCR24 protein, which is a potential protective factor against neuronal damage, was decreased at both mRNA and protein levels in the ipsilateral thalamus of MCAO rats. Conversely, bepridil treatment restored seladin-1/DHCR24 expression in the ipsilateral thalamus. Bepridil treatment did not significantly affect heme oxygenase-1- or NAD(P)H quinone oxidoreductase-1-mediated oxidative stress or inflammatory responses in the ipsilateral thalamus of MCAO rats. Finally, bepridil treatment mitigated MCAO-induced alterations in APP processing in the ipsilateral thalamus and improved contralateral forelimb use in MCAO rats. These findings suggest that bepridil is a plausible therapeutic candidate in AD or stroke owing to its multifunctional role in key cellular events that are relevant for the pathogenesis of these diseases. PMID:22805236

Neural Correlates of the Antinociceptive Effects of Stimulating the Anterior Pretectal Nucleus in Rats.

PubMed

Genaro, Karina; Prado, Wiliam A

2016-11-01

Stimulation-evoked antinociception (SEA) from the anterior pretectal nucleus (APtN) activates mechanisms that descend to the spinal cord through the dorsolateral funiculus, but the encephalic route followed by the descending pathways from the APtN is not completely known. This study evaluated the changes in the SEA from the APtN in the Wistar rat tail-flick test after lidocaine-induced neural block or N-methyl-d-aspartate-induced neurotoxic lesion of the deep mesencephalic nucleus (DpMe), tegmental pedunculopontine nucleus (PPTg), or lateral paragigantocellular nucleus (LPGi). The SEA from the APtN was less intense after neural block of the contralateral DpMe or PPTg or the ipsilateral LPGi, but was not changed by the neural block of the ipsilateral DpMe or PPTg or the contralateral LPGi. Antinociception did not occur when APtN stimulation was carried out 5 minutes after lidocaine or 6 days after N-methyl-d-aspartate injections into the contralateral DpMe and the ipsilateral LPGi, or into the contralateral PPTg and the ipsilateral LPGi. We conclude that the SEA from the APtN activates 2 descending pain inhibitory pathways, one relaying in the ipsilateral LPGi and another relaying sequentially in the contralateral DpMe and PPTg. The antinociceptive effect of the APtN stimulation involves 2 descending pathways: one relaying in the ipsilateral LPGi and another descending contralaterally via relays in the DpMe and PPTg. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Hyperphosphorylation of tau protein in the ipsilateral thalamus after focal cortical infarction in rats.

PubMed

Dong, Da-Wei; Zhang, Yu-Sheng; Yang, Wan-Yong; Wang-Qin, Run-Qi; Xu, An-Ding; Ruan, Yi-Wen

2014-01-16

Hyperphosphorylation of tau has been considered as an important risk factor for neurodegenerative diseases. It has been found also in the cortex after focal cerebral ischemia. The present study is aimed at investigating changes of tau protein expression in the ipsilateral thalamus remote from the primary ischemic lesion site after distal middle cerebral artery occlusion (MCAO). The number of neurons in the ventroposterior thalamic nucleus (VPN) was evaluated using Nissl staining and neuronal nuclei (NeuN) immunostaining. Total tau and phosphorylated tau at threonine 231 (p-T231-tau) and serine 199 (p-S199-tau) levels, respectively, in the thalamus were measured using immunostaining and immunoblotting. Moreover, apoptosis was detected with terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling (TUNEL) assay. It was found that the numbers of intact neurons and NeuN(+) cells within the ipsilateral VPN were reduced significantly compared with the sham-operated group, but the levels of p-T231-tau and p-S199-tau in the ipsilateral thalamus were increased significantly in rats subjected to ischemia for 3 days, 7 days and 28 days. Furthermore, the number of TUNEL-positive cells was increased in the ipsilateral VPN at 7 days and 28 days after MCAO. Thus, hyperphosphorylated tau protein is observed in ipsilateral thalamus after focal cerebral infarction in this study. Our findings suggest that the expression of hyperphosphorylated tau protein induced by ischemia may be associated with the secondary thalamic damage after focal cortical infarction via an apoptotic pathway. © 2013 Published by Elsevier B.V.

Ipsilateral hemiparesis in lateral medullary infarction: Clinical investigation of the lesion location on magnetic resonance imaging.

PubMed

Uemura, Masahiro; Naritomi, Hiroaki; Uno, Hisakazu; Umesaki, Arisa; Miyashita, Kotaro; Toyoda, Kazunori; Minematsu, Kazuo; Nagatsuka, Kazuyuki

2016-06-15

In 1946, Opalski reported two cases of Wallenberg syndrome with ipsilateral hemiparesis (IH). His hypothesis seems to be based on the view that IH is caused by post-decussating pyramidal tract damage. Afterwards, other researchers proposed a different hypothesis that ipsilateral sensory symptoms of limbs (ISSL) or ipsilateral limb ataxia (ILA) caused by lateral medullary infarction (LMI) might lead to ipsilateral motor weakness. The present study is aimed to clarify whether IH in LMI patients is attributable mainly to ISSL/ILA or disruption of ipsilateral post-decussating pyramidal tract. Thirty-two patients with acute LMI admitted during the last 13years were divided to IH Group (n=7) and Non-IH Group (n=25). Lesion location/distribution on MRI and neurological findings were compared between the two groups. LMI involved the lower medulla in all seven IH patients and 12 of 25 Non-IH patients. The lower medullary lesion extended to the cervico-medullary junction (CMJ) in four of seven IH patients and one of 12 Non-IH patients. Definitive extension to upper cervical cord (UCC) was confirmed in none of the patients. ISSL was found in two IH and three Non-IH patients all showing only superficial sensory impairments. ILA or hypotonia was observed in 57% of IH and 60% of Non-IH patients. IH in LMI appears to be due mainly to post-decussating pyramidal tract damage at the lower medulla instead of ILA or ISSL participation. Copyright © 2016 Elsevier B.V. All rights reserved.

A prospective profile of visual field loss following stroke: prevalence, type, rehabilitation, and outcome.

PubMed

Rowe, Fiona J; Wright, David; Brand, Darren; Jackson, Carole; Harrison, Shirley; Maan, Tallat; Scott, Claire; Vogwell, Linda; Peel, Sarah; Akerman, Nicola; Dodridge, Caroline; Howard, Claire; Shipman, Tracey; Sperring, Una; Macdiarmid, Sonia; Freeman, Cicely

2013-01-01

To profile site of stroke/cerebrovascular accident, type and extent of field loss, treatment options, and outcome. Prospective multicentre cohort trial. Standardised referral and investigation protocol of visual parameters. 915 patients were recruited with a mean age of 69 years (SD 14). 479 patients (52%) had visual field loss. 51 patients (10%) had no visual symptoms. Almost half of symptomatic patients (n = 226) complained only of visual field loss: almost half (n = 226) also had reading difficulty, blurred vision, diplopia, and perceptual difficulties. 31% (n = 151) had visual field loss as their only visual impairment: 69% (n = 328) had low vision, eye movement deficits, or visual perceptual difficulties. Occipital and parietal lobe strokes most commonly caused visual field loss. Treatment options included visual search training, visual awareness, typoscopes, substitutive prisms, low vision aids, refraction, and occlusive patches. At followup 15 patients (7.5%) had full recovery, 78 (39%) had improvement, and 104 (52%) had no recovery. Two patients (1%) had further decline of visual field. Patients with visual field loss had lower quality of life scores than stroke patients without visual impairment. Stroke survivors with visual field loss require assessment to accurately define type and extent of loss, diagnose coexistent visual impairments, and offer targeted treatment.

Ipsilateral hemiparesis and contralateral lower limb paresis caused by anterior cerebral artery territory infarct

PubMed Central

Xu, Yongfeng; Liu, Lan

2016-01-01

Ipsilateral hemiparesis is rare after a supratentorial stroke, and the role of reorganization in the motor areas of unaffected hemisphere is important for the rehabilitation of the stroke patients. In this study, we present a patient who had a subclinical remote infarct in the right pons developed ipsilateral hemiparesis and contralateral lower limb paresis caused by a new infarct in the left anterior cerebral artery territory. Our case suggests that the motor areas of the unaffected hemisphere might be reorganized after stroke, which is important for the rehabilitation of stroke patients. PMID:27356659

Ipsilateral hemiparesis and contralateral lower limb paresis caused by anterior cerebral artery territory infarct.

PubMed

Xu, Yongfeng; Liu, Lan

2016-07-01

Ipsilateral hemiparesis is rare after a supratentorial stroke, and the role of reorganization in the motor areas of unaffected hemisphere is important for the rehabilitation of the stroke patients. In this study, we present a patient who had a subclinical remote infarct in the right pons developed ipsilateral hemiparesis and contralateral lower limb paresis caused by a new infarct in the left anterior cerebral artery territory. Our case suggests that the motor areas of the unaffected hemisphere might be reorganized after stroke, which is important for the rehabilitation of stroke patients.

Transrectal Doppler sonography of uterine blood flow during the first two weeks after parturition in Simmenthal heifers

PubMed Central

Krüger, Lars; Leidl, Stephanie; Bollwein, Heinrich

2013-01-01

Transrectal Doppler sonography was used to evaluate uterine blood flow during the first two weeks after parturition in six primiparous Simmental cows. The uterine blood flow was evaluated on the day of parturition (Day 0), once daily from Days 1 to 8 and then every other day until Day 14. Blood flow was quantified by determining the diameter (D), the time-averaged maximum velocity (TAMV), the pulsatility index (PI) and the blood flow volume (BFV) of the uterine arteries ipsilateral and contralateral to the formerly pregnant uterine horn. During the first four days after calving D, TAMV and BFV declined (ipsilateral: TAMV 70%, BFV 87%, contralateral: D 47%, BFV 84%; p < 0.05), while PI increased (ipsilateral 158%, contralateral 100%; p < 0.05) distinctly. Between Days 4 and 14 only the ipsilateral D (12%) and the BFV of both arteries (ipsilateral 5%, contralateral 8%) decreased (p < 0.05). Blood flow variables were very strongly correlated with each other (r > ±0.75, p < 0.05), with negative correlations with PI and positive correlations with all other investigated factors. Overall, this study revealed characteristic changes in uterine perfusion during the first two weeks after parturition in cows that were pronounced during the first four days postpartum. PMID:23820167

Transrectal Doppler sonography of uterine blood flow during the first two weeks after parturition in Simmenthal heifers.

PubMed

Heppelmann, Maike; Krüger, Lars; Leidl, Stephanie; Bollwein, Heinrich

2013-01-01

Transrectal Doppler sonography was used to evaluate uterine blood flow during the first two weeks after parturition in six primiparous Simmental cows. The uterine blood flow was evaluated on the day of parturition (Day 0), once daily from Days 1 to 8 and then every other day until Day 14. Blood flow was quantified by determining the diameter (D), the time-averaged maximum velocity (TAMV), the pulsatility index (PI) and the blood flow volume (BFV) of the uterine arteries ipsilateral and contralateral to the formerly pregnant uterine horn. During the first four days after calving D, TAMV and BFV declined (ipsilateral: TAMV 70%, BFV 87%, contralateral: D 47%, BFV 84%; p < 0.05), while PI increased (ipsilateral 158%, contralateral 100%; p < 0.05) distinctly. Between Days 4 and 14 only the ipsilateral D (12%) and the BFV of both arteries (ipsilateral 5%, contralateral 8%) decreased (p < 0.05). Blood flow variables were very strongly correlated with each other (r > ±0.75, p < 0.05), with negative correlations with PI and positive correlations with all other investigated factors. Overall, this study revealed characteristic changes in uterine perfusion during the first two weeks after parturition in cows that were pronounced during the first four days postpartum.

Central Venous Occlusion in the Hemodialysis Patient.

PubMed

Krishna, Vinay Narasimha; Eason, Joseph B; Allon, Michael

2016-11-01

Central venous stenosis (CVS) is encountered frequently among hemodialysis patients. Prior ipsilateral central venous catheterization and cardiac rhythm device insertions are common risk factors, but CVS can also occur in the absence of this history. Chronic CVS can cause thrombosis with partial or complete occlusion of the central vein at the site of stenosis. CVS is frequently asymptomatic and identified as an incidental finding during imaging studies. Symptomatic CVS presents most commonly as an upper- or lower-extremity edema ipsilateral to the CVS. Previously unsuspected CVS may become symptomatic after placement of an ipsilateral vascular access. The likelihood of symptomatic CVS may be affected by the central venous catheter (CVC) location; CVC side; duration of CVC dependence; type, location, and blood flow of the ipsilateral access; and extent of collateral veins. Venous angiography is the gold standard for diagnosis. Percutaneous transluminal angioplasty and stent placement can improve the stenosis and alleviate symptoms, but CVS typically recurs frequently, requiring repeated interventions. Refractory symptomatic CVS may require ligation of the ipsilateral vascular access. Because no available treatment option is curative, the goal should be to prevent CVS by minimizing catheters and central vein instrumentation in patients with chronic kidney disease and dialysis patients. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Magnetic resonance direct thrombus imaging differentiates acute recurrent ipsilateral deep vein thrombosis from residual thrombosis.

PubMed

Tan, Melanie; Mol, Gerben C; van Rooden, Cornelis J; Klok, Frederikus A; Westerbeek, Robin E; Iglesias Del Sol, Antonio; van de Ree, Marcel A; de Roos, Albert; Huisman, Menno V

2014-07-24

Accurate diagnostic assessment of suspected ipsilateral recurrent deep vein thrombosis (DVT) is a major clinical challenge because differentiating between acute recurrent thrombosis and residual thrombosis is difficult with compression ultrasonography (CUS). We evaluated noninvasive magnetic resonance direct thrombus imaging (MRDTI) in a prospective study of 39 patients with symptomatic recurrent ipsilateral DVT (incompressibility of a different proximal venous segment than at the prior DVT) and 42 asymptomatic patients with at least 6-month-old chronic residual thrombi and normal D-dimer levels. All patients were subjected to MRDTI. MRDTI images were judged by 2 independent radiologists blinded for the presence of acute DVT and a third in case of disagreement. The sensitivity, specificity, and interobserver reliability of MRDTI were determined. MRDTI demonstrated acute recurrent ipsilateral DVT in 37 of 39 patients and was normal in all 42 patients without symptomatic recurrent disease for a sensitivity of 95% (95% CI, 83% to 99%) and a specificity of 100% (95% CI, 92% to 100%). Interobserver agreement was excellent (κ = 0.98). MRDTI images were adequate for interpretation in 95% of the cases. MRDTI is a sensitive and reproducible method for distinguishing acute ipsilateral recurrent DVT from 6-month-old chronic residual thrombi in the leg veins. © 2014 by The American Society of Hematology.

Inhibition of Cathepsin B Alleviates Secondary Degeneration in Ipsilateral Thalamus After Focal Cerebral Infarction in Adult Rats.

PubMed

Zuo, Xialin; Hou, Qinghua; Jin, Jizi; Zhan, Lixuan; Li, Xinyu; Sun, Weiwen; Lin, Kunqin; Xu, En

2016-09-01

Secondary degeneration in areas beyond ischemic foci can inhibit poststroke recovery. The cysteine protease Cathepsin B (CathB) regulates cell death and intracellular protein catabolism. To investigate the roles of CathB in the development of secondary degeneration in the ventroposterior nucleus (VPN) of the ipsilateral thalamus after focal cerebral infarction, infarct volumes, immunohistochemistry and immunofluorescence, and Western blotting analyses were conducted in a distal middle cerebral artery occlusion (dMCAO) stroke model in adult rats. We observed marked neuron loss and gliosis in the ipsilateral thalamus after dMCAO, and the expression of CathB and cleaved caspase-3 in the VPN was significantly upregulated; glial cells were the major source of CathB. Although it had no effect on infarct volume, delayed intracerebroventricular treatment with the membrane-permeable CathB inhibitor CA-074Me suppressed the expression of CathB and cleaved caspase-3 in ipsilateral VPN and accordingly alleviated the secondary degeneration. These data indicate that CathB mediates a novel mechanism of secondary degeneration in the VPN of the ipsilateral thalamus after focal cortical infarction and suggest that CathB might be a therapeutic target for the prevention of secondary degeneration in patients after stroke. © 2016 American Association of Neuropathologists, Inc. All rights reserved.

Cross-modal links among vision, audition, and touch in complex environments.

PubMed

Ferris, Thomas K; Sarter, Nadine B

2008-02-01

This study sought to determine whether performance effects of cross-modal spatial links that were observed in earlier laboratory studies scale to more complex environments and need to be considered in multimodal interface design. It also revisits the unresolved issue of cross-modal cuing asymmetries. Previous laboratory studies employing simple cues, tasks, and/or targets have demonstrated that the efficiency of processing visual, auditory, and tactile stimuli is affected by the modality, lateralization, and timing of surrounding cues. Very few studies have investigated these cross-modal constraints in the context of more complex environments to determine whether they scale and how complexity affects the nature of cross-modal cuing asymmetries. Amicroworld simulation of battlefield operations with a complex task set and meaningful visual, auditory, and tactile stimuli was used to investigate cuing effects for all cross-modal pairings. Significant asymmetric performance effects of cross-modal spatial links were observed. Auditory cues shortened response latencies for collocated visual targets but visual cues did not do the same for collocated auditory targets. Responses to contralateral (rather than ipsilateral) targets were faster for tactually cued auditory targets and each visual-tactile cue-target combination, suggesting an inhibition-of-return effect. The spatial relationships between multimodal cues and targets significantly affect target response times in complex environments. The performance effects of cross-modal links and the observed cross-modal cuing asymmetries need to be examined in more detail and considered in future interface design. The findings from this study have implications for the design of multimodal and adaptive interfaces and for supporting attention management in complex, data-rich domains.

Herpes Zoster Optic Neuropathy.

PubMed

Kaufman, Aaron R; Myers, Eileen M; Moster, Mark L; Stanley, Jordan; Kline, Lanning B; Golnik, Karl C

2018-06-01

Herpes zoster optic neuropathy (HZON) is a rare manifestation of herpes zoster ophthalmicus (HZO). The aim of our study was to better characterize the clinical features, therapeutic choices, and visual outcomes in HZON. A retrospective chart review was performed at multiple academic eye centers with the inclusion criteria of all eyes presenting with optic neuropathy within 1 month of cutaneous zoster of the ipsilateral trigeminal dermatome. Data were collected regarding presenting features, treatment regimen, and visual acuity outcomes. Six patients meeting the HZON inclusion criteria were identified. Mean follow-up was 2.75 months (range 0.5-4 months). Herpes zoster optic neuropathy developed at a mean of 14.1 days after initial rash (range 6-30 days). Optic neuropathy was anterior in 2 eyes and retrobulbar in 4 eyes. Other manifestations of HZO included keratoconjunctivitis (3 eyes) and iritis (4 eyes). All patients were treated with systemic antiviral therapy in addition to topical and/or systemic corticosteroids. At the last follow-up, visual acuity in 3 eyes had improved relative to presentation, 2 eyes had worsened, and 1 eye remained the same. The 2 eyes that did not receive systemic corticosteroids had the best observed final visual acuity. Herpes zoster optic neuropathy is an unusual but distinctive complication of HZO. Visual recovery after HZON is variable. Identification of an optimal treatment regiment for HZON could not be identified from our patient cohort. Systemic antiviral agents are a component of HZON treatment regimens. Efficacy of systemic corticosteroids for HZON remains unclear and should be considered on a case-by-case basis.

Indocyanine Green Videoangiography Transoptic Visualization and Clipping Confirmation of an Optic Splitting Ophthalmic Artery Aneurysm.

PubMed

Rustemi, Oriela; Cester, Giacomo; Causin, Francesco; Scienza, Renato; Della Puppa, Alessandro

2016-06-01

Ophthalmic artery aneurysms with medial and superior projection in exceptionally rare cases can split the optic nerve. Treatment of these aneurysms is challenging, because the aneurysm dome is hidden from the optic nerve, rendering its visualization and clipping confirmation difficult. In addition, optic nerve function should be preserved during surgical maneuvers. Preoperative detection of this growing feature is usually missing. We illustrate the first case of indocyanine green videoangiography (ICG-VA) application in an optic penetrating ophthalmic artery aneurysm treatment. A 57-year-old woman presented with temporal hemianopsia, slight right visual acuity deficit, and new onset of headache. The cerebral angiography detected a right ophthalmic artery aneurysm medially and superiorly projecting. The A1 tract of the ipsilateral anterior cerebral artery was elevated and curved, being suspicious for an under optic aneurysm growth. Surgery was performed. Initially the aneurysm was not visible. ICG-VA permitted the transoptic aneurysm visualization. After optic canal opening, the aneurysm was clipped and transoptic ICG-VA confirmed the aneurysm occlusion. ICG-VA showed also the slight improvement of the optic nerve pial vascularization. Postoperatively, the visual acuity was 10/10 and the hemianopsia did not worsen. The elevation and curve of the A1 tract in medially and superiorly projecting ophthalmic aneurysms may be an indirect sign of under optic growth, or optic splitting aneurysms. ICG-VA transoptic aneurysm detection and occlusion confirmation reduces the surgical maneuvers on the optic nerve, contributing to function preservation. Copyright © 2016 Elsevier Inc. All rights reserved.

Carotid-Falciform Optic Neuropathy: Microsurgical Treatment.

PubMed

Woodall, M Neil; Alleyne, Cargill H

2017-08-01

Several recent reports have implicated vascular ectasia and vessel contact in dysfunction of the visual apparatus. A subset of patients with prechiasmatic visual deterioration have an ectatic internal carotid artery (ICA) that displaces and flattens the optic nerve (ON) rostrally as the ON exits the skull base. We describe a proposed pathophysiologic mechanism and a straightforward surgical technique for dealing with this problem. Via an ipsilateral pterional craniotomy, the bony roof of the optic canal is removed. The falciform ligament is opened in parallel to the ON. Adhesions between the ICA and ON are then dissected, and a Teflon pledget is placed between the ICA and ON to complete the decompression. Patients both in the literature and in this series experienced an improvement in their vision postoperatively. We propose that 3 mechanisms contribute to this caroticofalciform optic neuropathy: 1) mass effect from ICA ectasia, 2) ON irritation from vessel pulsatility, and 3) indirect compression by the falciform ligament from above. This disease process can be treated safely using standard microsurgical techniques with excellent outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Successful medical treatment for globe penetration following tooth extraction in a dog.

PubMed

Guerreiro, Cleo E; Appelboam, Helen; Lowe, Robert C

2014-03-01

A five-year-old entire male Tibetan Terrier was referred for left-sided periorbital swelling and blepharospasm 4 days following ipsilateral maxillary tooth extraction. Examination of the left eye revealed mild exophthalmos, pain on retropulsion, and absent menace response and pupillary light reflexes. Examination of the posterior segment was not possible owing to the anterior segment pathology. Differential diagnoses considered were iatrogenic globe penetration and peribulbar abscess/cellulitis. Ocular ultrasound was consistent with a penetrating wound to the globe. Treatment with systemic prednisolone and marbofloxacin, and topical atropine sulfate 1%, prednisolone acetate, and brinzolamide was started. Marked clinical improvement allowed visual confirmation of the perforation. Oral prednisolone was tapered over the following 10 weeks. At final re-examination (10 months), the patient was visual, and fundic examination revealed an additional chorioretinal scar, most likely an exit wound that was obscured by vitreal debris on initial examinations. Neither scar was associated with retinal detachment. To the authors' knowledge, this is the first reported case of successful medical management of iatrogenic globe penetration following exodontic procedures. © 2013 American College of Veterinary Ophthalmologists.

Pseudo-low Frequency Hearing Loss and Its Improvement After Treatment May Be Objective Signs of Significant Vascular Pathology in Patients With Pulsatile Tinnitus.

PubMed

Jeon, Hyoung Won; Kim, So Young; Choi, Byung Se; Bae, Yun Jung; Koo, Ja-Won; Song, Jae-Jin

2016-10-01

In patients with pulsatile tinnitus (PT), physical examination such as auscultation with head position change or digital compression over the ipsilateral jugular vein provides physicians with important information. However, objective diagnosis of PT is sometimes limited because 1) audible bruit is absent on auscultation in some patients, 2) abnormal vascular structures found in radiologic evaluation is not always pathognomonic because they can be found in asymptomatic subjects as well, and 3) although an objective diagnostic tool using transcanal sound recording has recently been introduced, special equipment is needed. In this regard, recent studies that have reported ipsilateral low-frequency hearing loss (LFHL) on pure-tone audiometry (PTA) in some patients with PT, and its recovery after successful management, prompted us to conduct a retrospective observational study on the characteristics of the audiometric profile, the association between the audiometric profile and radiologic findings, and pre- and posttreatment changes in low-frequency hearing thresholds in PT patients. We tested two hypotheses: PT patients with marked vascular pathologies located close to the cochlea may show ipsilateral pseudo-LFHL (PLFHL) because of the masking effects of the PT itself, and their PLFHL may disappear if their vascular pathology is successfully managed by surgical or endovascular intervention. Retrospective case review. Tertiary referral center. A total of 85 PT subjects who underwent both audiologic and radiologic examinations. All patients' pre- and posttreatment PTA thresholds and radiologic findings were analyzed. By comparing the LFHL (an ipsilateral hearing threshold greater than 10 dB HL at both 250 and 500 Hz or greater than 20 dB HL at either 250 or 500 Hz compared with the contralateral side) group and a non-LFHL group with regard to the incidence of vascular structural abnormalities, we evaluated the incidence of abnormal vascular structures in the head and neck between the LFHL and non-LFHL groups. In addition, by comparing pre- and posttreatment PTA thresholds of seven PT patients with ipsilateral LFHL, we further evaluated the changes in low-frequency hearing thresholds and their role as an objective sign for diagnosis and outcome evaluation. Of 85 patients, 22 (25.9%) presented with ipsilateral LFHL. Compared with patients without this condition, patients with ipsilateral LFHL showed a significantly higher rate of abnormal vascular structure. In addition, most of the radiologic abnormalities found in the LFHL group were highly suspicious causative lesions that are responsible for the perception of PT according to the previous literature. In eight PT patients with ipsilateral LFHL who underwent both pre- and posttreatment audiograms, the average posttreatment pure-tone threshold at 250 Hz showed significant improvement compared with the pretreatment threshold. PT patients presenting with ipsilateral LFHL have higher possibility of having a discrete vascular pathology near the cochlea on radiologic evaluation. As ipsilateral LFHL improves in most patients after treatment, LFHL in patients with PT may be PLFHL because of the masking effects of the pulsatile sound, and the changes in the low-frequency thresholds may be applicable for objective diagnosis and evaluation of the effects of the treatment.

The four-meter confrontation visual field test.

PubMed Central

Kodsi, S R; Younge, B R

1992-01-01

The 4-m confrontation visual field test has been successfully used at the Mayo Clinic for many years in addition to the standard 0.5-m confrontation visual field test. The 4-m confrontation visual field test is a test of macular function and can identify small central or paracentral scotomas that the examiner may not find when the patient is tested only at 0.5 m. Also, macular sparing in homonymous hemianopias and quadrantanopias may be identified with the 4-m confrontation visual field test. We recommend use of this confrontation visual field test, in addition to the standard 0.5-m confrontation visual field test, on appropriately selected patients to obtain the most information possible by confrontation visual field tests. PMID:1494829

The four-meter confrontation visual field test.

PubMed

Kodsi, S R; Younge, B R

1992-01-01

The 4-m confrontation visual field test has been successfully used at the Mayo Clinic for many years in addition to the standard 0.5-m confrontation visual field test. The 4-m confrontation visual field test is a test of macular function and can identify small central or paracentral scotomas that the examiner may not find when the patient is tested only at 0.5 m. Also, macular sparing in homonymous hemianopias and quadrantanopias may be identified with the 4-m confrontation visual field test. We recommend use of this confrontation visual field test, in addition to the standard 0.5-m confrontation visual field test, on appropriately selected patients to obtain the most information possible by confrontation visual field tests.

Expression of mRNAs encoding dopamine receptors in striatal regions is differentially regulated by midbrain and hippocampal neurons.

PubMed

Brené, S; Herrera-Marschitz, M; Persson, H; Lindefors, N

1994-02-01

The glutamate analogue kainic acid was injected into the hippocampus of intact or 6-hydroxydopamine deafferented rats to investigate the influence of hippocampal neurons on the expression of dopamine D1 and D2 receptor mRNAs in subregions of the striatal complex and possible modulation by dopaminergic neurons. Quantitative in situ hybridization using 35S-labeled oligonucleotide probes specific for dopamine D1 and D2 receptor mRNAs, respectively, were used. It was found that an injection of kainic acid into the hippocampal formation had alone no significant effect on dopamine D1 or D2 receptor mRNA levels in any of the analyzed striatal subregions in animals analyzed 4 h after the injections. Kainic acid stimulation in the hippocampus ipsilateral to the dopamine lesion produced an increase in D1 receptor mRNA levels in the ipsilateral medial caudate-putamen, and a bilateral increase in core and shell of nucleus accumbens (ventral striatal limbic regions). A unilateral 6-hydroxydopamine lesion alone caused an increase in D2 receptor mRNA in the lateral caudate-putamen (dorsal striatal motor region) ipsilateral to the lesion and an increase in D1 receptor mRNA in the accumbens core ipsilateral to the lesion. However, in dopamine-lesioned animals, dopamine D1 receptor mRNA levels were increased bilaterally in nucleus accumbens core and shell and in the ipsilateral medial caudate-putamen following kainic acid stimulation in the hippocampus ipsilateral to the dopamine lesion. These results indicate a differential regulation of the expression of dopamine D1 and D2 receptor mRNAs by midbrain and hippocampal neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of High Ipsilateral Subventricular Zone Radiation Therapy Dose in Glioblastoma: A Pooled Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Percy, E-mail: percylee@mednet.ucla.edu; UCLA Jonsson Comprehensive Cancer Center, Los Angeles, California; Eppinga, Wietse

Purpose: Cancer stem cells (CSCs) may play a role in the recurrence of glioblastoma. They are believed to originate from neural stem cells in the subventricular zone (SVZ). Because of their radioresistance, we hypothesized that high doses of radiation (>59.4 Gy) to the SVZ are necessary to control CSCs and improve progression-free survival (PFS) or overall survival (OS) in glioblastoma. Methods and Materials: 173 patients with glioblastoma pooled from 2 academic centers were treated with resection followed by chemoradiation therapy. The SVZ was segmented on computed tomography to calculate radiation doses delivered to the presumptive CSC niches. The relationships betweenmore » high SVZ doses and PFS and OS were examined using Cox proportional hazards models. Five covariates were included to estimate their impact on PFS or OS: ipsilateral and contralateral SVZ doses, clinical target volume dose, age, and extent of resection. Results: Median PFS and OS were 10.4 and 19.6 months for the cohort. The mean ipsilateral SVZ, contralateral SVZ, and clinical target volume doses were 49.2, 35.2, and 60.1 Gy, respectively. Twenty-one patients who received high ipsilateral SVZ dose (>59.4 Gy) had significantly longer median PFS (12.6 vs 9.9 months, P=.042) and longer OS (25.8 vs 19.2 months, P=.173). On multivariate analysis, high radiation therapy doses to ipsilateral SVZ remained a statistically significant independent predictor of improved PFS but not of OS. The extent of surgery affected both PFS and OS on multivariate analysis. Conclusion: High radiation therapy doses to ipsilateral CSC niches are associated with improved PFS in glioblastoma.« less

Association between Champagne Bottle Neck Sign of Internal Carotid Artery and Ipsilateral Hemorrhagic Stroke in Patients with Moyamoya Disease.

PubMed

Wang, Jian; Chen, Gong; Yang, Yongbo; Zhang, Bing; Jia, Zhongzhi; Gu, Peiyuan; Wei, Dong; Ji, Jing; Hu, Weixing; Zhao, Xihai

2018-06-15

To assess the association between champagne bottle neck sign (CBNS) in carotid artery and intracranial hemorrhage in patients with moyamoya disease (MMD). From January 2016 to December 2017, a total of 76 consecutive patients with MMD without definite risk factors associated intracranial hemorrhage who underwent preoperative angiography were included in this retrospective study. CBNS was defined as luminal diameter of internal carotid artery (ICA)/common carotid artery (CCA) ≤ 0.5 on angiographic imaging. The right and left cerebral hemisphere in each patient was separately identified as hemorrhagic and none-hemorrhagic. The association between CBNS and intracranial hemorrhage was analyzed. Of 76 MMD patients, intracranial hemorrhage was found in 44 (28.9%) hemispheres of 152 and 6.8% (3/44) had multiple events. Compared carotid arteries without intracranial hemorrhage in the ipsilateral hemispheres, those with intracranial hemorrhage in the ipsilateral hemispheres had significantly smaller luminal diameter ratio of ICA/CCA (0.49 ± 0.11 vs. 0.55 ± 0.12, p < 0.01) and higher prevalence of CBNS (63.7% vs. 41.7%, p = 0.01). For hemispheres with intracranial hemorrhage, those with ipsilateral carotid artery CBNS had significantly higher prevalence of hemorrhage at posterior territories than those without (57.1% vs. 23.1%, p=0.05). Logistic regression revealed that CBNS was significantly associated with ipsilateral intracranial hemorrhage before (OR, 2.45; 95% CI, 1.19-5.05; p=0.02) and after (OR, 3.43; 95% CI, 1.50-7.87; p<0.01) adjusted for female, lenticulostriate anastomosis, and choroidal anastomosis. CBNS is significantly associated with intracranial hemorrhage at ipsilateral hemisphere in MMD patients, particularly for intracranial hemorrhage at posterior territories. Copyright © 2018. Published by Elsevier Inc.

Midshaft clavicle fractures with associated ipsilateral acromioclavicular joint dislocations: Incidence and risk factors.

PubMed

Ottomeyer, Christina; Taylor, Benjamin C; Isaacson, Mark; Martinez, Lara; Ebaugh, Pierce; French, Bruce G

2017-02-01

Simultaneous ipsilateral clavicle and acromioclavicular (AC) joint injury have been infrequently reported in the literature at this time. The purpose of this study was to assess incidence as well as assess risk factors for this dual injury pattern. We performed a retrospective review of a prospectively collected database (Level III evidence), evaluating 383 adult patients without previous shoulder girdle injury or trauma with a minimum 1-year follow-up who sustained a displaced diaphyseal clavicle fracture. All patients in the study underwent either nonoperative management or surgical reduction and stabilization of a diaphyseal clavicle fracture with a plate and screw construct. Study subjects were followed with serial radiographs. Clavicle and shoulder radiographs, as well as chest radiographs and contralateral films in questionable cases, were used to assess for acromioclavicular joint injury in both operative and nonoperative groups. Additional data was collected on concurrent injuries, patient demographics, fracture characteristics, fixation techniques, surgical/post-operative data, and operative or nonoperative treatment. We found that 13/183 (7.1%) of patients undergoing fixation of a diaphyseal clavicle fracture had an ipsilateral AC joint injury, while 13/200 (6.5%) of patients undergoing conservative management had an ipsilateral AC joint injury. Critical analysis of the data revealed that presence of ipsilateral scapular body fractures, and a likely incidental association with superior plating fixation, were associated with an increased rate of this injury pattern. Ipsilateral clavicle fracture and AC joint injury is much more common than traditionally believed, with an incidence of 6.8% overall. It is unknown how the presence of an associated AC injury influences outcome, as AC injury was not universally symptomatic. Copyright © 2016 Elsevier Ltd. All rights reserved.

Functional MRI and intraoperative brain mapping to evaluate brain plasticity in patients with brain tumours and hemiparesis

PubMed Central

Roux, F; Boulanouar, K; Ibarrola, D; Tremoulet, M; Chollet, F; Berry, I

2000-01-01

OBJECTIVE—To support the hypothesis about the potential compensatory role of ipsilateral corticofugal pathways when the contralateral pathways are impaired by brain tumours.
METHODS—Retrospective analysis was carried out on the results of functional MRI (fMRI) of a selected group of five paretic patients with Rolandic brain tumours who exhibited an abnormally high ipsilateral/contralateral ratio of activation—that is, movements of the paretic hand activated predominately the ipsilateral cortex. Brain activation was achieved with a flexion extension of the fingers. Statistical parametric activation was obtained using a t test and a threshold of p<0.001. These patients, candidates for tumour resection, also underwent cortical intraoperative stimulation that was correlated to the fMRI spatial data using three dimensional reconstructions of the brain. Three patients also had postoperative control fMRI.
RESULTS—The absence of fMRI activation of the primary sensorimotor cortex normally innervating the paretic hand for the threshold chosen, was correlated with completely negative cortical responses of the cortical hand area during the operation. The preoperative fMRI activation of these patients predominantly found in the ipsilateral frontal and primary sensorimotor cortices could be related to the residual ipsilateral hand function. Postoperatively, the fMRI activation returned to more classic patterns of activation, reflecting the consequences of therapy.
CONCLUSION—In paretic patients with brain tumours, ipsilateral control could be implicated in the residual hand function, when the normal primary pathways are impaired. The possibility that functional tissue still remains in the peritumorous sensorimotor cortex even when the preoperative fMRI and the cortical intraoperative stimulations are negative, should be taken into account when planning the tumour resection and during the operation.

 PMID:10990503

Long-term Outcome of Unconstrained Primary Total Hip Arthroplasty in Ipsilateral Residual Poliomyelitis.

PubMed

Buttaro, Martín A; Slullitel, Pablo A; García Mansilla, Agustín M; Carlucci, Sofía; Comba, Fernando M; Zanotti, Gerardo; Piccaluga, Francisco

2017-03-01

Incapacitating articular sequelae in the hip joint have been described for patients with late effects of poliomyelitis. In these patients, total hip arthroplasty (THA) has been associated with a substantial rate of dislocation. This study was conducted to evaluate the long-term clinical and radiologic outcomes of unconstrained THA in this specific group of patients. The study included 6 patients with ipsilateral polio who underwent primary THA between 1985 and 2006. Patients with polio who underwent THA on the nonparalytic limb were excluded. Mean follow-up was 119.5 months (minimum, 84 months). Clinical outcomes were evaluated with the modified Harris Hip Score (mHHS) and the visual analog scale (VAS) pain score. Radiographs were examined to identify the cause of complications and determine the need for revision surgery. All patients showed significantly better functional results when preoperative and postoperative mHHS (67.58 vs 87.33, respectively; P=.002) and VAS pain score (7.66 vs 2, respectively; P=.0003) were compared. Although 2 cases of instability were diagnosed, only 1 patient needed acetabular revision as a result of component malpositioning. None of the patients had component loosening, osteolysis, or infection. Unconstrained THA in the affected limb of patients with poliomyelitis showed favorable long-term clinical results, with improved function and pain relief. Nevertheless, instability may be a more frequent complication in this group of patients compared with the general population. [Orthopedics. 2017; 40(2):e255-e261.]. Copyright 2016, SLACK Incorporated.

Poster — Thur Eve — 10: Partial kV CBCT, complete kV CBCT and EPID in breast treatment: a dose comparison study for skin, breasts, heart and lungs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roussin, E; Archambault, L K; Wierzbicki, W

The advantages of kilovoltage cone beam CT (kV CBCT) imaging over electronic portal imaging device (EPID) such as accurate 3D anatomy, soft tissue visualization, fast rigid registration and enhanced precision on patient positioning has lead to its increasing use in clinics. The benefits of this imaging technique are at the cost of increasing the dose to healthy surrounding organs. Our center has moved toward the use of daily partial rotation kV CBCT to restrict the dose to healthy tissues. This study aims to better quantify radiation doses from different image-guidance techniques such as tangential EPID, complete and partial kV CBCTmore » for breast treatments. Cross-calibrated ionization chambers and kV calibrated Gafchromic films were used to measure the dose to the heart, lungs, breasts and skin. It was found that performing partial kV CBCT decreases the heart dose by about 36%, the lungs dose by 31%, the contralateral breast dose by 41% and the ipsilateral breast dose by 43% when compared to a full rotation CBCT. The skin dose measured for a full rotation CBCT was about 0.8 cGy for the contralateral breast and about 0.3 cGy for the ipsilateral breast. The study is still ongoing and results on skin doses for partial rotation kV CBCT as well as for tangential EPID images are upcoming.« less

Ipsilateral kidney sparing in treatment of pancreatic malignancies using volumetric-modulated arc therapy avoidance sectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Raymond W., E-mail: rwc3b@alumni.virginia.edu; Podgorsak, Matthew B.

Recent research has shown treating pancreatic cancer with volumetric-modulated arc therapy (VMAT) to be superior to either intensity-modulated radiation therapy or 3-dimensional conformal radiotherapy (3D-CRT), with respect to reducing normal tissue toxicity, monitor units, and treatment time. Furthermore, using avoidance sectors with RapidArc planning can further reduce normal tissue dose while maintaining target conformity. This study looks at the methods in reducing dose to the ipsilateral kidney, in pancreatic head cases, while observing dose received by other critical organs using avoidance sectors. Overall, 10 patients were retrospectively analyzed. Each patient had preoperative/unresectable pancreatic tumor and were selected based on themore » location of the right kidney being situated within the traditional 3D-CRT treatment field. The target planning target volume (286.97 ± 85.17 cm{sup 3}) was prescribed to 50.4 Gy using avoidance sectors of 30°, 40°, and 50° and then compared with VMAT as well as 3D-CRT. Analysis of the data shows that the mean dose to the right kidney was reduced by 11.6%, 15.5%, and 21.9% for avoidance angles of 30°, 40°, and 50°, respectively, over VMAT. The mean dose to the total kidney also decreased by 6.5%, 8.5%, and 11.0% for the same increasing angles. Spinal cord maximum dose, however, increased as a function of angle by 3.7%, 4.8%, and 6.1% compared with VMAT. Employing avoidance sector angles as a complement to VMAT planning can significantly reduce high dose to the ipsilateral kidney while not greatly overdosing other critical organs.« less

Functional and structural aspects of tinnitus-related enhancement and suppression of auditory cortex activity.

PubMed

Diesch, Eugen; Andermann, Martin; Flor, Herta; Rupp, Andre

2010-05-01

The steady-state auditory evoked magnetic field was recorded in tinnitus patients and controls, both either musicians or non-musicians, all of them with high-frequency hearing loss. Stimuli were AM-tones with two modulation frequencies and three carrier frequencies matching the "audiometric edge", i.e. the frequency above which hearing loss increases more rapidly, the tinnitus frequency or the frequency 1 1/2 octaves above the audiometric edge in controls, and a frequency 1 1/2 octaves below the audiometric edge. Stimuli equated in carrier frequency, but differing in modulation frequency, were simultaneously presented to the two ears. The modulation frequency-specific components of the dual steady-state response were recovered by bandpass filtering. In both hemispheres, the source amplitude of the response was larger for contralateral than ipsilateral input. In non-musicians with tinnitus, this laterality effect was enhanced in the hemisphere contralateral and reduced in the hemisphere ipsilateral to the tinnitus ear, especially for the tinnitus frequency. The hemisphere-by-input laterality dominance effect was smaller in musicians than in non-musicians. In both patient groups, source amplitude change over time, i.e. amplitude slope, was increasing with tonal frequency for contralateral input and decreasing for ipsilateral input. However, slope was smaller for musicians than non-musicians. In patients, source amplitude was negatively correlated with the MRI-determined volume of the medial partition of Heschl's gyrus. Tinnitus patients show an altered excitatory-inhibitory balance reflecting the downregulation of inhibition and resulting in a steeper dominance hierarchy among simultaneous processes in auditory cortex. Direction and extent of this alteration are modulated by musicality and auditory cortex volume. 2010 Elsevier Inc. All rights reserved.

Mobile phone use and risk of glioma: a case-control study in Korea for 2002-2007

PubMed Central

An, Hyonggin; Choi, Hyong Do

2015-01-01

Objectives There has been a growing concern about the possible carcinogenic effects of the electromagnetic radiofrequency fields emitted from mobile phones. The purpose of this study was to investigate the association between mobile phone use and the development of gliomas in Korea. Methods Our study methods were based on the International Interphone study that aimed to evaluate possible adverse effects of mobile phone use. This study included 285 histologically-confirmed Korean patients 15 to 69 years of age, with gliomas diagnosed between 2002 and 2007 in 9 hospitals. The 285 individually matched controls were healthy individuals that had their medical check-up in the same hospitals. Unconditional logistic regression was used to calculate the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for use of mobile phones. Results For the entire group, no significant relationship was investigated between gliomas and regular use of mobile phones, types of mobile phones, lifetime years of use, monthly service fee, and the other exposure indices. Analyses restricted to self-respondents showed similar results. For ipsilateral users, whose the body side for usual mobile phone use match the location of glioma, the aORs (95% CIs) for lifetime years of use and cumulative hours of use were 1.25 (0.55 to 2.88) and 1.77 (0.32 to 1.84), respectively. However, the contralateral users showed slightly lower risk than ipsilateral users. Conclusions Our results do not support the hypothesis that the use of mobile phones increases the risk of glioma; however, we found a non-significant increase in risk among ipsilateral users. These findings suggest further evaluation for glioma risk among long-term mobile phone users. PMID:26726040

The nucleus of the optic tract (NOT) and the dorsal terminal nucleus (DTN) of opossums (Didelphis marsupialis aurita).

PubMed

Vargas, C D; Volchan, E; Nasi, J P; Bernardes, R F; Rocha-Miranda, C E

1996-01-01

Wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was injected unilaterally into the pretectocollicular region of opossums (Didelphis marsupialis aurita), primarily to investigate the existence of a commissural subcortical pathway but also to reveal afferents and efferents of the nucleus of the optic tract (NOT) and dorsal terminal nucleus (DTN) in this species. Labelled cells and terminals were observed in the contralateral NOT-DTN. Furthermore, HRP was injected bilaterally in the region of the inferior olive (IO) to verify if the distribution of labelled cells in the NOT-DTN overlapped the region of commissural labelled cells. The two subpopulations of retrogradely labelled cells coincided, being distributed within the retinal terminal field attributed to the NOT-DTN, as revealed by contralateral eye injections of HRP. The commissural cells were located slightly more ventral than the olivary cells in the optic tract. The pretectocollicular WGA-HRP injections also labelled cells and terminals bilaterally in the lateral terminal nucleus (LTN), interstitial nucleus of the superior fasciculus, posterior fibers (INSFp), ventral lateral geniculate nucleus (vLGN), and superior colliculus (SC) and ipsilaterally in the medial terminal nucleus (MTN). In addition, further caudally, labelled cells and terminals were observed bilaterally in the nuclei prepositus hypoglossi (PH) and in the medial (MVN) and lateral (LVN) vestibular nuclei. Labelled terminals were found in the ipsilateral nucleus reticularis tegmenti pontis (NRTP) and in the IO with ipsilateral predominance. This study allowed an anatomical delimitation of the NOT-DTN in this opossum species, as defined by the olivary and commissural subpopulations, as well as a hodological evaluation of this region. The existence of some common anatomical aspects with other mammalian species is discussed.

Breast conserving treatment for breast cancer: dosimetric comparison of different non-invasive techniques for additional boost delivery

PubMed Central

2014-01-01

Background Today it is unclear which technique for delivery of an additional boost after whole breast radiotherapy for breast conserved patients should be state of the art. We present a dosimetric comparison of different non-invasive treatment techniques for additional boost delivery. Methods For 10 different tumor bed localizations, 7 different non-invasive treatment plans were made. Dosimetric comparison of PTV-coverage and dose to organs at risk was performed. Results The Vero system achieved an excellent PTV-coverage and at the same time could minimize the dose to the organs at risk with an average near-maximum-dose (D2) to the heart of 0.9 Gy and the average volume of ipsilateral lung receiving 5 Gy (V5) of 1.5%. The TomoTherapy modalities delivered an average D2 to the heart of 0.9 Gy for the rotational and of 2.3 Gy for the static modality and an average V5 to the ipsilateral lung of 7.3% and 2.9% respectively. A rotational technique offers an adequate conformity at the cost of more low dose spread and a larger build-up area. In most cases a 2-field technique showed acceptable PTV-coverage, but a bad conformity. Electrons often delivered a worse PTV-coverage than photons, with the planning requirements achieved only in 2 patients and with an average D2 to the heart of 2.8 Gy and an average V5 to the ipsilateral lung of 5.8%. Conclusions We present advices which can be used as guidelines for the selection of the best individualized treatment. PMID:24467916

The Multisensory Attentional Consequences of Tool Use: A Functional Magnetic Resonance Imaging Study

PubMed Central

Holmes, Nicholas P.; Spence, Charles; Hansen, Peter C.; Mackay, Clare E.; Calvert, Gemma A.

2008-01-01

Background Tool use in humans requires that multisensory information is integrated across different locations, from objects seen to be distant from the hand, but felt indirectly at the hand via the tool. We tested the hypothesis that using a simple tool to perceive vibrotactile stimuli results in the enhanced processing of visual stimuli presented at the distal, functional part of the tool. Such a finding would be consistent with a shift of spatial attention to the location where the tool is used. Methodology/Principal Findings We tested this hypothesis by scanning healthy human participants' brains using functional magnetic resonance imaging, while they used a simple tool to discriminate between target vibrations, accompanied by congruent or incongruent visual distractors, on the same or opposite side to the tool. The attentional hypothesis was supported: BOLD response in occipital cortex, particularly in the right hemisphere lingual gyrus, varied significantly as a function of tool position, increasing contralaterally, and decreasing ipsilaterally to the tool. Furthermore, these modulations occurred despite the fact that participants were repeatedly instructed to ignore the visual stimuli, to respond only to the vibrotactile stimuli, and to maintain visual fixation centrally. In addition, the magnitude of multisensory (visual-vibrotactile) interactions in participants' behavioural responses significantly predicted the BOLD response in occipital cortical areas that were also modulated as a function of both visual stimulus position and tool position. Conclusions/Significance These results show that using a simple tool to locate and to perceive vibrotactile stimuli is accompanied by a shift of spatial attention to the location where the functional part of the tool is used, resulting in enhanced processing of visual stimuli at that location, and decreased processing at other locations. This was most clearly observed in the right hemisphere lingual gyrus. Such modulations of visual processing may reflect the functional importance of visuospatial information during human tool use. PMID:18958150

Adaptive Acceleration of Visually Evoked Smooth Eye Movements in Mice

PubMed Central

2016-01-01

The optokinetic response (OKR) consists of smooth eye movements following global motion of the visual surround, which suppress image slip on the retina for visual acuity. The effective performance of the OKR is limited to rather slow and low-frequency visual stimuli, although it can be adaptably improved by cerebellum-dependent mechanisms. To better understand circuit mechanisms constraining OKR performance, we monitored how distinct kinematic features of the OKR change over the course of OKR adaptation, and found that eye acceleration at stimulus onset primarily limited OKR performance but could be dramatically potentiated by visual experience. Eye acceleration in the temporal-to-nasal direction depended more on the ipsilateral floccular complex of the cerebellum than did that in the nasal-to-temporal direction. Gaze-holding following the OKR was also modified in parallel with eye-acceleration potentiation. Optogenetic manipulation revealed that synchronous excitation and inhibition of floccular complex Purkinje cells could effectively accelerate eye movements in the nasotemporal and temporonasal directions, respectively. These results collectively delineate multiple motor pathways subserving distinct aspects of the OKR in mice and constrain hypotheses regarding cellular mechanisms of the cerebellum-dependent tuning of movement acceleration. SIGNIFICANCE STATEMENT Although visually evoked smooth eye movements, known as the optokinetic response (OKR), have been studied in various species for decades, circuit mechanisms of oculomotor control and adaptation remain elusive. In the present study, we assessed kinematics of the mouse OKR through the course of adaptation training. Our analyses revealed that eye acceleration at visual-stimulus onset primarily limited working velocity and frequency range of the OKR, yet could be dramatically potentiated during OKR adaptation. Potentiation of eye acceleration exhibited different properties between the nasotemporal and temporonasal OKRs, indicating distinct visuomotor circuits underlying the two. Lesions and optogenetic manipulation of the cerebellum provide constraints on neural circuits mediating visually driven eye acceleration and its adaptation. PMID:27335412

The mechanism of ipsilateral ataxia in lacunar hemiparesis: SPECT perfusion imaging.

PubMed

Yamamoto, Ryoo; Johkura, Ken; Nakae, Yoshiharu; Tanaka, Fumiaki

2015-01-01

Although ataxic hemiparesis is a common lacunar syndrome, the precise mechanism underlying hemiataxia is not clear. We attempted to identify ataxia-related, cerebral blood flow changes in patients presenting with ataxic hemiparesis after acute capsular infarct. We used 99mTc-ECD brain perfusion single-photon emission computed tomography to evaluate regional cerebral blood flow in 12 patients with ataxic hemiparesis caused by capsular infarct, and we compared the regional blood flow of these patients with that of 11 patients with pure motor hemiparesis caused by similar lesions. The ipsilateral red nucleus blood flow was significantly decreased in the ataxic hemiparesis patients, whereas the ipsilateral red nucleus blood flow was increased in the pure motor hemiparesis patients. Crossed cerebellar diaschisis (decreased contralateral cerebellar blood flow) was seen in ataxic hemiparesis patients; similarly, it was seen in pure motor hemiparesis patients. Our findings suggest that ataxia in hemiparetic patients with capsular infarct can be caused by ipsilateral red nucleus dysfunction secondary to cortico-rubral pathway disruption at the internal capsule.

Movement compatibility for configurations of displays located in three cardinal orientations and ipsilateral, contralateral and overhead controls.

PubMed

Chan, Alan H S; Hoffmann, Errol R

2012-01-01

Stereotype strength and reversibility were determined for displays that were in the Front, Right and Left orientations relative to the operator, along with rotary, horizontally and vertically-moving controls located in the overhead, left-sagittal and right-sagittal planes. In each case, responses were made using the left and right hands. The arrangements used were (i) rotary control with a circular display (ii) horizontal/transverse control moving forward/rearward in the left and right-sagittal planes or transversely in the overhead plane and (iii) vertical/longitudinal control moving vertically in the left and right-sagittal planes and longitudinally in the overhead plane. These are all combinations not previously researched. Stereotype strength varied with display plane, type of control and plane of control. Models for the stereotype strength are developed, showing the contribution of various components to the overall stereotype strength. The major component for horizontally-moving controls comes from the "visual field" model of Worringham and Beringer (1998); for the rotary control important factors are "clockwise-for-clockwise" and the hand/control location effect (Hoffmann, 2009a). Vertically-moving controls are governed by a simple 'up-for-up' relationship between displays and controls. Overall stereotype strength is a maximum when all components add positively. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Temporal information entropy of the Blood-Oxygenation Level-Dependent signals increases in the activated human primary visual cortex

NASA Astrophysics Data System (ADS)

DiNuzzo, Mauro; Mascali, Daniele; Moraschi, Marta; Bussu, Giorgia; Maraviglia, Bruno; Mangia, Silvia; Giove, Federico

2017-02-01

Time-domain analysis of blood-oxygenation level-dependent (BOLD) signals allows the identification of clusters of voxels responding to photic stimulation in primary visual cortex (V1). However, the characterization of information encoding into temporal properties of the BOLD signals of an activated cluster is poorly investigated. Here, we used Shannon entropy to determine spatial and temporal information encoding in the BOLD signal within the most strongly activated area of the human visual cortex during a hemifield photic stimulation. We determined the distribution profile of BOLD signals during epochs at rest and under stimulation within small (19-121 voxels) clusters designed to include only voxels driven by the stimulus as highly and uniformly as possible. We found consistent and significant increases (2-4% on average) in temporal information entropy during activation in contralateral but not ipsilateral V1, which was mirrored by an expected loss of spatial information entropy. These opposite changes coexisted with increases in both spatial and temporal mutual information (i.e. dependence) in contralateral V1. Thus, we showed that the first cortical stage of visual processing is characterized by a specific spatiotemporal rearrangement of intracluster BOLD responses. Our results indicate that while in the space domain BOLD maps may be incapable of capturing the functional specialization of small neuronal populations due to relatively low spatial resolution, some information encoding may still be revealed in the temporal domain by an increase of temporal information entropy.

Brief Communication: visual-field superiority as a function of stimulus type and content: further evidence.

PubMed

Basu, Anamitra; Mandal, Manas K

2004-07-01

The present study examined visual-field advantage as a function of presentation mode (unilateral, bilateral), stimulus structure (facial, lexical), and stimulus content (emotional, neutral). The experiment was conducted in a split visual-field paradigm using a JAVA-based computer program with recognition accuracy as the dependent measure. Unilaterally, rather than bilaterally, presented stimuli were significantly better recognized. Words were significantly better recognized than faces in the right visual-field; the difference was nonsignificant in the left visual-field. Emotional content elicited left visual-field and neutral content elicited right visual-field advantages. Copyright Taylor and Francis Inc.

A comparative study of standard intensity-modulated radiotherapy and RapidArc planning techniques for ipsilateral and bilateral head and neck irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pursley, Jennifer, E-mail: jpursley@mgh.harvard.edu; Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA; Damato, Antonio L.

The purpose of this study was to investigate class solutions using RapidArc volumetric-modulated arc therapy (VMAT) planning for ipsilateral and bilateral head and neck (H&N) irradiation, and to compare dosimetric results with intensity-modulated radiotherapy (IMRT) plans. A total of 14 patients who received ipsilateral and 10 patients who received bilateral head and neck irradiation were retrospectively replanned with several volumetric-modulated arc therapy techniques. For ipsilateral neck irradiation, the volumetric-modulated arc therapy techniques included two 360° arcs, two 360° arcs with avoidance sectors around the contralateral parotid, two 260° or 270° arcs, and two 210° arcs. For bilateral neck irradiation, themore » volumetric-modulated arc therapy techniques included two 360° arcs, two 360° arcs with avoidance sectors around the shoulders, and 3 arcs. All patients had a sliding-window-delivery intensity-modulated radiotherapy plan that was used as the benchmark for dosimetric comparison. For ipsilateral neck irradiation, a volumetric-modulated arc therapy technique using two 360° arcs with avoidance sectors around the contralateral parotid was dosimetrically comparable to intensity-modulated radiotherapy, with improved conformity (conformity index = 1.22 vs 1.36, p < 0.04) and lower contralateral parotid mean dose (5.6 vs 6.8 Gy, p < 0.03). For bilateral neck irradiation, 3-arc volumetric-modulated arc therapy techniques were dosimetrically comparable to intensity-modulated radiotherapy while also avoiding irradiation through the shoulders. All volumetric-modulated arc therapy techniques required fewer monitor units than sliding-window intensity-modulated radiotherapy to deliver treatment, with an average reduction of 35% for ipsilateral plans and 67% for bilateral plans. Thus, for ipsilateral head and neck irradiation a volumetric-modulated arc therapy technique using two 360° arcs with avoidance sectors around the contralateral parotid is recommended. For bilateral neck irradiation, 2- or 3-arc techniques are dosimetrically comparable to intensity-modulated radiotherapy, but more work is needed to determine the optimal approaches by disease site.« less

A comparative study of standard intensity-modulated radiotherapy and RapidArc planning techniques for ipsilateral and bilateral head and neck irradiation.

PubMed

Pursley, Jennifer; Damato, Antonio L; Czerminska, Maria A; Margalit, Danielle N; Sher, David J; Tishler, Roy B

2017-01-01

The purpose of this study was to investigate class solutions using RapidArc volumetric-modulated arc therapy (VMAT) planning for ipsilateral and bilateral head and neck (H&N) irradiation, and to compare dosimetric results with intensity-modulated radiotherapy (IMRT) plans. A total of 14 patients who received ipsilateral and 10 patients who received bilateral head and neck irradiation were retrospectively replanned with several volumetric-modulated arc therapy techniques. For ipsilateral neck irradiation, the volumetric-modulated arc therapy techniques included two 360° arcs, two 360° arcs with avoidance sectors around the contralateral parotid, two 260° or 270° arcs, and two 210° arcs. For bilateral neck irradiation, the volumetric-modulated arc therapy techniques included two 360° arcs, two 360° arcs with avoidance sectors around the shoulders, and 3 arcs. All patients had a sliding-window-delivery intensity-modulated radiotherapy plan that was used as the benchmark for dosimetric comparison. For ipsilateral neck irradiation, a volumetric-modulated arc therapy technique using two 360° arcs with avoidance sectors around the contralateral parotid was dosimetrically comparable to intensity-modulated radiotherapy, with improved conformity (conformity index = 1.22 vs 1.36, p < 0.04) and lower contralateral parotid mean dose (5.6 vs 6.8Gy, p < 0.03). For bilateral neck irradiation, 3-arc volumetric-modulated arc therapy techniques were dosimetrically comparable to intensity-modulated radiotherapy while also avoiding irradiation through the shoulders. All volumetric-modulated arc therapy techniques required fewer monitor units than sliding-window intensity-modulated radiotherapy to deliver treatment, with an average reduction of 35% for ipsilateral plans and 67% for bilateral plans. Thus, for ipsilateral head and neck irradiation a volumetric-modulated arc therapy technique using two 360° arcs with avoidance sectors around the contralateral parotid is recommended. For bilateral neck irradiation, 2- or 3-arc techniques are dosimetrically comparable to intensity-modulated radiotherapy, but more work is needed to determine the optimal approaches by disease site. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

Reticular Formation Connections Underlying Horizontal Gaze: The Central Mesencephalic Reticular Formation (cMRF) as a Conduit for the Collicular Saccade Signal.

PubMed

Wang, Niping; Perkins, Eddie; Zhou, Lan; Warren, Susan; May, Paul J

2017-01-01

The central mesencephalic reticular formation (cMRF) occupies much of the core of the midbrain tegmentum. Physiological studies indicate that it is involved in controlling gaze changes, particularly horizontal saccades. Anatomically, it receives input from the ipsilateral superior colliculus (SC) and it has downstream projections to the brainstem, including the horizontal gaze center located in the paramedian pontine reticular formation (PPRF). Consequently, it has been hypothesized that the cMRF plays a role in the spatiotemporal transformation needed to convert spatially coded collicular saccade signals into the temporally coded signals utilized by the premotor neurons of the horizontal gaze center. In this study, we used neuroanatomical tracers to examine the patterns of connectivity of the cMRF in macaque monkeys in order to determine whether the circuit organization supports this hypothesis. Since stimulation of the cMRF produces contraversive horizontal saccades and stimulation of the horizontal gaze center produces ipsiversive saccades, this would require an excitatory cMRF projection to the contralateral PPRF. Injections of anterograde tracers into the cMRF did produce labeled terminals within the PPRF. However, the terminations were denser ipsilaterally. Since the PPRF located contralateral to the movement direction is generally considered to be silent during a horizontal saccade, we then tested the hypothesis that this ipsilateral reticuloreticular pathway might be inhibitory. The ultrastructure of ipsilateral terminals was heterogeneous, with some displaying more extensive postsynaptic densities than others. Postembedding immunohistochemistry for gamma-aminobutyric acid (GABA) indicated that only a portion (35%) of these cMRF terminals are GABAergic. Dual tracer experiments were undertaken to determine whether the SC provides input to cMRF reticuloreticular neurons projecting to the ipsilateral pons. Retrogradely labeled reticuloreticular neurons were predominantly distributed in the ipsilateral cMRF. Anterogradely labeled tectal terminals were observed in close association with a portion of these retrogradely labeled reticuloreticular neurons. Taken together, these results suggest that the SC does have connections with reticuloreticular neurons in the cMRF. However, the predominantly excitatory nature of the ipsilateral reticuloreticular projection argues against the hypothesis that this cMRF pathway is solely responsible for producing a spatiotemporal transformation of the collicular saccade signal.

A glial palisade delineates the ipsilateral optic projection in Monodelphis.

PubMed

MacLaren, R E

1998-01-01

In developing marsupials, the path taken through the optic chiasm by ipsilaterally projecting retinal ganglion cells is complicated. Just prior to entry into the chiasm, ganglion cells destined for the ipsilateral optic tract separate from the remainder of axons by turning abruptly downwards to take a position in the ventral part of the optic nerve. In this report, it is shown that a discrete population of about 10-15 large glial cells transiently form a linear array across the prechiasmatic part of the optic nerve, precisely at this axon turning point. The distinct morphology of these cells and their novel location may reflect a specialized role in axon guidance.

Compartment syndrome of the thigh complicating surgical treatment of ipsilateral femur and ankle fractures

NASA Technical Reports Server (NTRS)

Moore, M. R.; Garfin, S. R.; Hargens, A. R.

1987-01-01

A 26-year-old man presented with ipsilateral femur and ankle fractures. The patient was treated with interlocking nail of his femur fracture, followed by open reduction and internal fixation of his ankle fracture under tourniquet control. Postoperatively, the patient developed compartment syndrome of his thigh with elevated pressures, requiring decompressive fasciotomies. This case illustrates the possible complication of treating a femur fracture with intramedullary nailing and then immediately applying a tourniquet to treat an ipsilateral extremity fracture. Because of the complication with this patient, we feel the procedure should be staged, or a tourniquet should be avoided if possible.

The accuracy of confrontation visual field test in comparison with automated perimetry.

PubMed Central

Johnson, L. N.; Baloh, F. G.

1991-01-01

The accuracy of confrontation visual field testing was determined for 512 visual fields using automated static perimetry as the reference standard. The sensitivity of confrontation testing excluding patchy defects was 40% for detecting anterior visual field defects, 68.3% for posterior defects, and 50% for both anterior and posterior visual field defects combined. The sensitivity within each group varied depending on the type of visual field defect encountered. Confrontation testing had a high sensitivity (75% to 100%) for detecting altitudinal visual loss, central/centrocecal scotoma, and homonymous hemianopsia. Confrontation testing was fairly insensitive (20% to 50% sensitivity) for detecting arcuate scotoma and bitemporal hemianopsia. The specificity of confrontation testing was high at 93.4%. The high positive predictive value (72.6%) and negative predictive value (75.7%) would indicate that visual field defects identified during confrontation testing are often true visual field defects. However, the many limitations of confrontation testing should be remembered, particularly its low sensitivity for detecting visual field loss associated with parasellar tumors, glaucoma, and compressive optic neuropathies. PMID:1800764

Influence of two-electrode montages on the level-specific (LS) CE-Chirp auditory brainstem response (ABR) at multiple intensity levels.

PubMed

Dzulkarnain, Ahmad Aidil Arafat; Noor Ibrahim, Siti Hajra Mu'minah; Anuar, Nur Farah Aida; Abdullah, Siti Aisyah; Tengku Zam Zam, Tengku Zulaila Hasma; Rahmat, Sarah; Mohd Ruzai, Muhammad Amar

2017-10-01

To investigate the influence of two different electrode montages (ipsilateral: reference to mastoid and vertical: reference to nape of neck) to the ABR results recorded using a level-specific (LS)-CE-Chirp® in normally hearing subjects at multiple intensities levels. Quasi-experimental and repeated measure study designs were applied in this study. Two different stopping criteria were used, (1) a fixed-signal averaging 4000 sweeps and, (2) a minimum quality indicator of Fmp = 3.1 with a minimum of 800 sweeps. Twenty-nine normally hearing adults (18 females, 11 male) participated. Wave V amplitudes were significantly larger in the LS CE-Chirp® recorded from the vertical montage than the ipsilateral montage. Waves I and III amplitudes were significantly larger from the ipsilateral LS CE-Chirp® than from the other montages and stimulus combinations. The differences in the quality of the ABR recording between the vertical and ipsilateral montages were marginal. Overall, the result suggested that the vertical LS CE-Chirp® ABR had a high potential for a threshold-seeking application, because it produced a higher wave V amplitude. The Ipsilateral LS CE-Chirp® ABR, on the other hand, might also have a high potential for the site of lesion application, because it produced larger waves I and III amplitudes.

One-Lung Ventilation with Additional Ipsilateral Ventilation of Low Tidal Volume and High Frequency in Lung Lobectomy

PubMed Central

Feng, Yong; Wang, Jianyue; Zhang, Yang; Wang, Shiduan

2016-01-01

Background To investigate the protective effects of additional ipsilateral ventilation of low tidal volume and high frequency on lung functions in the patients receiving lobectomy. Material/Methods Sixty patients receiving lung lobectomy were randomized into the conventional one-lung ventilation (CV) group (n=30) and the ipsilateral low tidal volume high frequency ventilation (LV) group (n=30). In the CV group, patients received only contralateral OLV. In the LV group, patients received contralateral ventilation and additional ipsilateral ventilation of low tidal volume of 1–2 ml/kg and high frequency of 40 times/min. Normal lung tissues were biopsied for the analysis of lung injury. Lung injury was scored by evaluating interstitial edema, alveolar edema, neutrophil infiltration, and alveolar congestion. Results At 30 min and 60 min after the initiation of one-lung ventilation and after surgery, patients in the LV group showed significantly higher ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen than those in the CV group (P<0.001). Lung injury was significantly less severe (2.7±0.7) in the LV group than in the CV group (3.1±0.7) (P=0.006). Conclusions Additional ipsilateral ventilation of low tidal volume and high frequency can decrease the risk of hypoxemia and alleviate lung injury in patients receiving lobectomy. PMID:27166086

Bilateral responses of upper limb muscles to transcranial magnetic stimulation in human subjects.

PubMed

Bawa, P; Hamm, J D; Dhillon, P; Gross, P A

2004-10-01

Anatomical and behavioural work on primates has shown bilateral innervation of axial and proximal limb muscles, and contralateral control of distal limb muscles. The following study examined if a clear boundary exists between the distal and proximal upper limb muscles that are controlled contralaterally or bilaterally. The right motor cortical area representing the upper limb was stimulated, while surface EMG was recorded bilaterally from various upper limb muscles during rest and phasic voluntary contractions. Peak-to-peak amplitude of motor evoked potential (MEP) was measured for each muscle on both sides. The ratio R = (ipsilateral MEP: contralateral MEP) was calculated for seven pairs of muscles. For each of the seven pairs, R was less than 1.0, implying that for each muscle and subject, the contralateral control is stronger. The boundary where R changed from almost zero to a clearly measurable magnitude depended on the subject. Ipsilateral MEPs from trapezius and pectoralis could be recorded with a small background contraction from almost all subjects; on the other hand, in deltoid and biceps brachii, ipsilateral MEPs were observed only with bimanual phasic contractions. The forearm and hand muscles, in general, did not show any ipsilateral MEPs. Major differences between subjects lay in the presence or the absence of ipsilateral MEPs in biceps brachii and deltoid, without defining a sharp boundary between proximal and distal muscles.

Somatosensory temporal discrimination is prolonged during migraine attacks.

PubMed

Boran, H Evren; Cengiz, Bülent; Bolay, Hayrunnisa

2016-01-01

Symptoms and signs of sensorial disturbances are characteristic features of a migraine headache. Somatosensory temporal discrimination measures the temporal threshold to perceive two separate somaesthetic stimuli as clearly distinct. This study aimed to evaluate somaesthetic perception in migraine patients by measuring the somatosensory temporal discrimination thresholds. The study included 12 migraine patients without aura and 12 volunteers without headache. Somatosensory temporal discrimination threshold (STDT) values were measured in the face (V3) and hands (C7) during a lateralized headache attack and the headache-free interictal period. The disease duration, pain intensity, phonophobia, photophobia, nausea, vomiting, and brush allodynia were also recorded during the migraine attack. STDT values were within normal limits and not different between the control group and the interictal period in migraine patients. Compared to the headache-free period, STDT values during the attack were significantly prolonged in the contralateral hand (C7) (155.7 ± 84.2 vs 40.6 ± 16.1 ms [P < .001]), ipsilateral hand (C7) (88.6 ± 51.3 vs 31.4 ± 14.2 ms [P < 0.001]), contralateral face (V3) (65.5 ± 35.4 vs 37.6 ± 22.2 ms [P = .006]) and ipsilateral face (V3) (104.1 ± 44.5 vs 37.5 ± 21.4 ms [P < 0.001]) according to the lateralization of the headache. Ictal STDT values of the contralateral hand and ipsilateral face were significantly increased compared to that of the ipsilateral hand and contralateral face (155.7 ± 84.2 ms vs 88.6 ± 5.1.3 ms [P = .001], 104.1 ± 44.5 ms vs 65.5 ± 35.4 ms [P = 0.001]). No allodynia was detected in the areas that were tested for somatosensory temporal discrimination. The visual analog scale scores were correlated with the somatosensory temporal discrimination thresholds of the contralateral hand (r = 0.602, P = .038), whereas no correlation was detected between the somatosensory temporal discrimination thresholds and disease duration, brush allodynia in the forehead, phonophobia, photophobia, nausea and vomiting. The study demonstrates for the first time that somatosensory temporal discrimination thresholds are elevated during migraine attacks. A transient disruption of the central processing of somaesthetic stimuli during the lateralized migraine attack may provide additional information to understand the mechanisms of the cognitive and sensory perception impairment associated with migraine headache and may have diagnostic value. © 2015 American Headache Society.

Structural and functional correlates of visual field asymmetry in the human brain by diffusion kurtosis MRI and functional MRI.

PubMed

O'Connell, Caitlin; Ho, Leon C; Murphy, Matthew C; Conner, Ian P; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C

2016-11-09

Human visual performance has been observed to show superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine whether the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI, respectively, in 15 healthy individuals at 3 T. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In diffusion kurtosis MRI, the brain regions mapping to the lower visual field showed higher mean kurtosis, but not fractional anisotropy or mean diffusivity compared with the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing.

Functional visual fields: relationship of visual field areas to self-reported function.

PubMed

Subhi, Hikmat; Latham, Keziah; Myint, Joy; Crossland, Michael D

2017-07-01

The aim of this study is to relate areas of the visual field to functional difficulties to inform the development of a binocular visual field assessment that can reflect the functional consequences of visual field loss. Fifty-two participants with peripheral visual field loss undertook binocular assessment of visual fields using the 30-2 and 60-4 SITA Fast programs on the Humphrey Field Analyser, and mean thresholds were derived. Binocular visual acuity, contrast sensitivity and near reading performance were also determined. Self-reported overall and mobility function were assessed using the Dutch ICF Activity Inventory. Greater visual field loss (0-60°) was associated with worse self-reported function both overall (R 2 = 0.50; p < 0.0001), and for mobility (R 2 = 0.64; p < 0.0001). Central (0-30°) and peripheral (30-60°) visual field areas were similarly related to mobility function (R 2 = 0.61, p < 0.0001 and R 2 = 0.63, p < 0.0001 respectively), although the peripheral (30-60°) visual field was the best predictor of mobility self-reported function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R 2 = 0.56, p < 0.0001 and R 2 = 0.67, p < 0.0001 respectively). The inferior field was found to be the best predictor of mobility function in multiple regression analysis. Mean threshold of the binocular visual field to 60° eccentricity is a good predictor of self-reported function overall, and particularly of mobility function. Both the central (0-30°) and peripheral (30-60°) mean threshold are good predictors of self-reported function, but the peripheral (30-0°) field is a slightly better predictor of mobility function, and should not be ignored when considering functional consequences of field loss. The inferior visual field is a slightly stronger predictor of perceived overall and mobility function than the superior field. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

SOURCES OF BINOCULAR SUPRATHRESHOLD VISUAL FIELD LOSS IN A COHORT OF OLDER WOMEN BEING FOLLOWED FOR RISK OF FALLS (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)

PubMed Central

Coleman, Anne Louise

2007-01-01

Purpose To determine the sources of binocular visual field loss most strongly associated with falls in a cohort of older women. Methods In the Study of Osteoporotic Fractures, women with severe binocular visual field loss had an increased risk of two or more falls during the 12 months following the eye examination. The lens and fundus photographs of the 422 women with severe binocular visual field loss, plus a random sample of 141 white women with no, mild, or moderate binocular visual field loss—47 white women with no binocular visual field loss, 46 white women with mild binocular visual field loss, and 48 white women with moderate binocular visual field loss —were evaluated for lens opacities, glaucomatous optic nerve damage, age-related macular degeneration, and diabetic retinopathy. Results Eighty-four percent of the women with severe binocular visual field loss had ocular disease in one or both eyes. Bilateral cataracts and glaucomatous optic nerve damage were the most common sources of this severe binocular visual field loss. Approximately 15.2% of women had no evidence of lens opacities, glaucomatous optic nerve damage, age-related macular degeneration, or diabetic retinopathy. Conclusion Severe binocular visual field loss due primarily to cataracts, glaucoma, and age-related macular degeneration explains 33.3% of the falls among women who fell frequently. Because binocular visual field loss may be treatable and/or preventable, screening programs for binocular visual field loss and subsequent referral for intervention and treatment are recommended as a strategy for preventing falls among the elderly. PMID:18427619

SU-E-T-307: Dosimetric Comparison of Prone Versus Supine Positioning for Adjuvant Breast Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, C; O’Connor, B; Hayes, L

Purpose: The prone treatment position has been used to reduce ipsilateral lung and heart dose in left breast radiation. We conducted a retrospective study to evaluate the difference in the dosimetry between prone and supine treatment positions. Methods: Eight left breast cancer patients were simulated in both the supine and prone positions as a pretreatment evaluation for the optimal treatment position. Treatment plans were created for all patients in both the supine and prone positions using a field in field three dimensional planning technique. Prescribed dose was 45 Gy delivered by two tangential photon fields. Irradiated volume (IV) was evaluatedmore » by V50, V100, and dose to lung and heart by V5, V10, V20, and the mean dose were evaluated. Results: All dosimetry metrics for both the supine and prone plans met our internal normal structure guidelines which are based on Quantec data. The average IVs (50% and 100%) were 2223cc and 1361cc prone, 2315cc and 1315cc supine. The average ipsilateral lung Mean dose (0.83Gy prone vs 5.8Gy supine), V5 (1.6% prone vs 20.9% supine), V10 (0.78% prone vs 15% supine) and V20 (0.36% prone vs 11% supine) were significantly lower in prone position. Heart Mean dose (1.4Gy prone vs 2.9Gy supine), V10 (1.4% prone vs 5.0% supine) and V20 (0.4% prone vs 3.5% supine) were found improved for all patients except one where the mean dose was the same and all other values were improved. Conclusion: The prone position offer preferable dosimetry for all patients planned in our study. These patients were chosen based on the physician’s belief that they would benefit from prone treatment either because they had large pendulous breasts or due to the amount of heart seen in the field on CT simulation.« less

IMRT vs. 3D Noncoplanar Treatment Plans for Maxillary Sinus Tumors: A New Tool for Quantitative Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levin, Daphne; Menhel, Janna; Alezra, Dror

2008-01-01

We compared 9-field, equispaced intensity modulated radiation therapy (IMRT), 4- to 5-field, directionally optimized IMRT, and 3-dimensional (3D) noncoplanar planning approaches for tumors of the maxillary sinus. Ten patients were planned retrospectively to compare the different treatment techniques. Prescription doses were 60 to 70 Gy. Critical structures contoured included optic nerves and chiasm, lacrimal glands, lenses, and retinas. As an aid for plan assessment, we introduced a new tool: Critical Organ Scoring Index (COSI), which allows quantitative evaluation of the tradeoffs between target coverage and critical organ sparing. This index was compared with other, commonly used conformity indices. For amore » reliable assessment of both tumor coverage and dose to critical organs in the different planning techniques, we introduced a 2D, graphical representation of COSI vs. conformity index (CI). Dose-volume histograms and mean, maximum, and minimum organ doses were also compared. IMRT plans delivered lower doses to ipsilateral structures, but were unable to spare them. 3D plans delivered less dose to contralateral structures, and were more homogeneous, as well. Both IMRT approaches gave similar results. In cases where choice of optimal plan was difficult, the novel 2D COSI-CI representation gave an accurate picture of the tradeoffs between target coverage and organ sparing, even in cases where other conformity indices failed. Due to their unique anatomy, maxillary sinus tumors may benefit more from a noncoplanar approach than from IMRT. The new graphical representation proposed is a quick, visual, reliable tool, which may facilitate the physician's choice of best treatment plan for a given patient.« less

The SCHEIE Visual Field Grading System

PubMed Central

Sankar, Prithvi S.; O’Keefe, Laura; Choi, Daniel; Salowe, Rebecca; Miller-Ellis, Eydie; Lehman, Amanda; Addis, Victoria; Ramakrishnan, Meera; Natesh, Vikas; Whitehead, Gideon; Khachatryan, Naira; O’Brien, Joan

2017-01-01

Objective No method of grading visual field (VF) defects has been widely accepted throughout the glaucoma community. The SCHEIE (Systematic Classification of Humphrey visual fields-Easy Interpretation and Evaluation) grading system for glaucomatous visual fields was created to convey qualitative and quantitative information regarding visual field defects in an objective, reproducible, and easily applicable manner for research purposes. Methods The SCHEIE grading system is composed of a qualitative and quantitative score. The qualitative score consists of designation in one or more of the following categories: normal, central scotoma, paracentral scotoma, paracentral crescent, temporal quadrant, nasal quadrant, peripheral arcuate defect, expansive arcuate, or altitudinal defect. The quantitative component incorporates the Humphrey visual field index (VFI), location of visual defects for superior and inferior hemifields, and blind spot involvement. Accuracy and speed at grading using the qualitative and quantitative components was calculated for non-physician graders. Results Graders had a median accuracy of 96.67% for their qualitative scores and a median accuracy of 98.75% for their quantitative scores. Graders took a mean of 56 seconds per visual field to assign a qualitative score and 20 seconds per visual field to assign a quantitative score. Conclusion The SCHEIE grading system is a reproducible tool that combines qualitative and quantitative measurements to grade glaucomatous visual field defects. The system aims to standardize clinical staging and to make specific visual field defects more easily identifiable. Specific patterns of visual field loss may also be associated with genetic variants in future genetic analysis. PMID:28932621

Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters

PubMed Central

Qiu, Bo; Liang, Jian; Xie, Weihao; Deng, Xiaowu; Qi, Zhenyu

2017-01-01

Objective: To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. Materials and Methods: Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated. Results: The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised. Conclusions: Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification. PMID:28423624

Natural course of visual field loss in patients with Type 2 Usher syndrome.

PubMed

Fishman, Gerald A; Bozbeyoglu, Simge; Massof, Robert W; Kimberling, William

2007-06-01

To evaluate the natural course of visual field loss in patients with Type 2 Usher syndrome and different patterns of visual field loss. Fifty-eight patients with Type 2 Usher syndrome who had at least three visual field measurements during a period of at least 3 years were studied. Kinetic visual fields measured on a standard calibrated Goldmann perimeter with II4e and V4e targets were analyzed. The visual field areas in both eyes were determined by planimetry with the use of a digitalizing tablet and computer software and expressed in square inches. The data for each visual field area measurement were transformed to a natural log unit. Using a mixed model regression analysis, values for the half-life of field loss (time during which half of the remaining field area is lost) were estimated. Three different patterns of visual field loss were identified, and the half-life time for each pattern of loss was calculated. Of the 58 patients, 11 were classified as having pattern type I, 12 with pattern type II, and 14 with pattern type III. Of 21 patients whose visual field loss was so advanced that they could not be classified, 15 showed only a small residual central field (Group A) and 6 showed a residual central field with a peripheral island (Group B). The average half-life times varied between 3.85 and 7.37 for the II4e test target and 4.59 to 6.42 for the V4e target. There was no statistically significant difference in the half-life times between the various patterns of field loss or for the test targets. The average half-life times for visual field loss in patients with Usher syndrome Type 2 were statistically similar among those patients with different patterns of visual field loss. These findings will be useful for counseling patients with Type 2 Usher syndrome as to their prognosis for anticipated visual field loss.

A case of unilateral, systematized linear hair follicle nevi associated with epidermal nevus-like lesions.

PubMed

Ikeda, Shigaku; Kawada, Juri; Yaguchi, Hitoshi; Ogawa, Hideoki

2003-01-01

Multiple hair follicle nevi are an extremely rare condition. In 1998, a case of unilateral multiple hair follicle nevi, ipsilateral alopecia and ipsilateral leptomeningeal angiomatosis of the brain was first reported from Japan. Very recently, hair follicle nevus in a distribution following Blaschko's lines has also been reported. In this paper, we observed a congenital case of unilateral, systematized linear hair follicle nevi associated with congenital, ipsilateral, multiple plaque lesions resembling epidermal nevi but lacking leptomeningeal angiomatosis of the brain. These cases implicate the possibility of a novel neurocutaneous syndrome. Additional cases should be sought in order to determine whether this condition is pathophysiologically distinct. Copyright 2003 S. Karger AG, Basel

Structural and Functional Correlates of Visual Field Asymmetry in the Human Brain by Diffusion Kurtosis MRI and Functional MRI

PubMed Central

O’Connell, Caitlin; Ho, Leon C.; Murphy, Matthew C.; Conner, Ian P.; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C.

2016-01-01

Human visual performance has been observed to exhibit superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine if the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI (DKI), respectively in 15 healthy individuals at 3 Tesla. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In DKI, the brain regions mapping to the lower visual field exhibited higher mean kurtosis but not fractional anisotropy or mean diffusivity when compared to the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing. PMID:27631541

A Multidisciplinary Orbit-Sparing Treatment Approach That Includes Proton Therapy for Epithelial Tumors of the Orbit and Ocular Adnexa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holliday, Emma B.; Esmaeli, Bita; Pinckard, Jamie

Purpose: Postoperative radiation is often indicated in the treatment of malignant epithelial tumors of the orbit and ocular adnexa. We present details of radiation technique and toxicity data after orbit-sparing surgery followed by adjuvant proton radiation therapy. Methods and Materials: Twenty patients underwent orbit-sparing surgery followed by proton therapy for newly diagnosed malignant epithelial tumors of the lacrimal gland (n=7), lacrimal sac/nasolacrimal duct (n=10), or eyelid (n=3). Tumor characteristics, treatment details, and visual outcomes were obtained from medical records. Acute and chronic toxicity were prospectively scored using Common Terminology Criteria for Adverse Events version 4.0. Results: The median radiation dosemore » was 60 Gy(RBE) (relative biological effectiveness; [range 50-70 Gy]); 11 patients received concurrent chemotherapy. Dose to ipsilateral anterior optic structures was reduced in 13 patients by having them gaze away from the target during treatment. At a median follow-up time of 27.1 months (range 2.6-77.2 months), no patient had experienced local recurrence; 1 had regional and 1 had distant recurrence. Three patients developed chronic grade 3 epiphora, and 3 developed grade 3 exposure keratopathy. Four patients experienced a decrease in visual acuity from baseline but maintained vision sufficient to perform all activities of daily living without difficulty. Patients with grade ≥3 chronic ocular toxicity had higher maximum dose to the ipsilateral cornea (median 46.3 Gy[RBE], range 36.6-52.7 Gy[RBE] vs median 37.4 Gy[RBE], range 9.0-47.3 Gy(RBE); P=.017). Conclusions: Orbit-sparing surgery for epithelial tumors of the orbit and ocular adnexa followed by proton therapy successfully achieved disease control and was well tolerated. No patient required orbital exenteration or enucleation. Chronic grade 3 toxicity was associated with high maximum dose to the cornea. An eye-deviation technique can be used to limit the maximum corneal dose to <35 Gy(RBE).« less

Assessment of the vision-specific quality of life using clustered visual field in glaucoma patients.

PubMed

Sawada, Hideko; Yoshino, Takaiko; Fukuchi, Takeo; Abe, Haruki

2014-02-01

To investigate the significance of vision-specific quality of life (QOL) in glaucoma patients based on the location of visual field defects. We examined 336 eyes of 168 patients. The 25-item National Eye Institute Visual Function Questionnaire was used to evaluate patients' QOL. Visual field testing was performed using the Humphrey Field Analyzer; the visual field was divided into 10 clusters. We defined the eye with better mean deviation as the better eye and the fellow eye as the worse eye. A single linear regression analysis was applied to assess the significance of the relationship between QOL and the clustered visual field. The strongest correlation was observed in the lower paracentral visual field in the better eye. The lower peripheral visual field in the better eye also showed a good correlation. Correlation coefficients in the better eye were generally higher than those in the worse eye. For driving, the upper temporal visual field in the better eye was the most strongly correlated (r=0.509). For role limitation and peripheral vision, the lower peripheral visual field in the better eye had the highest correlation coefficients at 0.459 and 0.425, respectively. Overall, clusters in the lower hemifield in the better eye were more strongly correlated with QOL than those in the worse eye. In particular, the lower paracentral visual field in the better eye was correlated most strongly of all. Driving, however, strongly correlated with the upper hemifield in the better eye.

Caffeine, Adenosine Receptors and Estrogen in Toxin Models of Parkinson’s Disease

DTIC Science & Technology

2007-10-01

KW-6002 (3 mg/kg, ip; in the presence of a sub-threshold dose of the dopamine D2 antagonist haloperidol ) induced ipsilateral turning, and amphetamine... haloperidol ) induced ipsilateral turning, and amphetamine (2.5 mg/kg i.p. on its own) induced contralateral turning relative to that in the control

Visual acuity and visual field impairment in Usher syndrome.

PubMed

Edwards, A; Fishman, G A; Anderson, R J; Grover, S; Derlacki, D J

1998-02-01

To determine the extent of visual acuity and visual field impairment in patients with types 1 and 2 Usher syndrome. The records of 53 patients with type 1 and 120 patients with type 2 Usher syndrome were reviewed for visual acuity and visual field area at their most recent visit. Visual field areas were determined by planimetry of the II4e and V4e isopters obtained with a Goldmann perimeter. Both ordinary and logistic regression models were used to evaluate differences in visual acuity and visual field impairment between patients with type 1 and type 2 Usher syndrome. The difference in visual acuity of the better eye between patients with type 1 and type 2 varied by patient age (P=.01, based on a multiple regression model). The maximum difference in visual acuity between the 2 groups occurred during the third and fourth decades of life (with the type 1 patients being more impaired), while more similar acuities were seen in both younger and older patients. Fifty-one percent (n=27) of the type 1 patients had a visual acuity of 20/40 or better in at least 1 eye compared with 72% (n=87) of the type 2 patients (age-adjusted odds ratio, 3.9). Visual field area to both the II4e (P=.001) and V4e (P<.001) targets was more impaired in the better eye of type 1 patients than type 2 patients. A concentric central visual field greater than 20 degrees in at least 1 eye was present in 20 (59%) of the available 34 visual fields of type 1 patients compared with 70 (67%) of the available 104 visual fields of type 2 patients (age-adjusted odds ratio, 2.9) with the V4e target and in 6 (21%) of the available 29 visual fields of type 1 patients compared with 36 (38%) of the available 94 visual fields of type 2 patients (age-adjusted odds ratio, 4.9) with the II4e target. The fraction of patients who had a visual acuity of 20/40 or better and a concentric central visual field greater than 20 degrees to the II4e target in at least 1 eye was 17% (n=5) in the type 1 patients and 35% (n=33) in the type 2 patients (age-adjusted odds ratio, 3.9). Visual acuity and visual field area were more impaired in patients with type 1 than type 2 Usher syndrome. Of note, 27 of 53 type 1 (51%) and 87 of 120 type 2 (72%) patients had a visual acuity of 20/40 or better in at least 1 eye. These data are useful for overall counseling of patients with Usher syndrome.

Receptors signaling gravity orientation in an insect

NASA Technical Reports Server (NTRS)

Hartman, H. B.

1982-01-01

Displacement in any direction from primary orientation is found to evoke tonic activity from at least one of the four interneurons of a certain type of burrowing cockroach; the receptive field for each interneuron is slightly more than a quadrant. The receptive field of each interneuron is found to be the same as the row of receptors providing the input. Displacement about the least stable axis (0-180 deg) or roll, on the one hand, and the most stable axis (90-270 deg) or pitch, on the other, is found to be unambiguously signaled by pairs of interneurons. Indications are obtained that receptors in the lateral row drive a giant interneuron in a contralateral connective and those in the medial row drive one in an ipsilateral connective.

Estimating corresponding locations in ipsilateral breast tomosynthesis views

NASA Astrophysics Data System (ADS)

van Schie, Guido; Tanner, Christine; Karssemeijer, Nico

2011-03-01

To improve cancer detection in mammography, breast exams usually consist of two views per breast. To combine information from both views, radiologists and multiview computer-aided detection (CAD) systems need to match corresponding regions in the two views. In digital breast tomosynthesis (DBT), finding corresponding regions in ipsilateral volumes may be a difficult and time-consuming task for radiologists, because many slices have to be inspected individually. In this study we developed a method to quickly estimate corresponding locations in ipsilateral tomosynthesis views by applying a mathematical transformation. First a compressed breast model is matched to the tomosynthesis view containing a point of interest. Then we decompress, rotate and compress again to estimate the location of the corresponding point in the ipsilateral view. In this study we use a simple elastically deformable sphere model to obtain an analytical solution for the transformation in a given DBT case. The model is matched to the volume by using automatic segmentation of the pectoral muscle, breast tissue and nipple. For validation we annotated 181 landmarks in both views and applied our method to each location. Results show a median 3D distance between the actual location and estimated location of 1.5 cm; a good starting point for a feature based local search method to link lesions for a multiview CAD system. Half of the estimated locations were at most 1 slice away from the actual location, making our method useful as a tool in mammographic workstations to interactively find corresponding locations in ipsilateral tomosynthesis views.

Transfer of ipsilateral fibula on vascular pedicle for treatment of congenital pseudarthrosis of the tibia.

PubMed

Tan, Jane S; Roach, James W; Wang, Angela A

2011-01-01

Although the use of free vascularized fibula grafts has frequently been reported in the treatment of congenital pseudarthrosis of the tibia, the use of ipsilateral fibula graft on a vascular pedicle is uncommon. We reviewed the long-term results of this procedure in 11 patients. The records of 11 patients who underwent transfer of the ipsilateral fibula on a vascular pedicle between 2.1 and 10.8 years of age were retrospectively reviewed. Average follow-up was 11 years after the index procedure. Seven patients had reached skeletal maturity. Clinical records and radiographs were reviewed to determine patient demographics, surgical parameters, union rate, refracture rate, residual deformity, and functional outcome. Eight patients (73%) achieved union at an average of 20.1 months. Additional bone grafting procedures were required in 4 patients with distal nonunions. There were 3 refractures (38%). Four patients eventually underwent amputation, and 1 patient had a persistent nonunion at final follow-up. Residual deformity included tibial valgus and procurvatum deformities, limb length discrepancy, and ankle valgus. Use of the ipsilateral fibula did not seem to increase the risk of ankle valgus. Functional outcomes were good in all but one patient. Use of the ipsilateral fibula as a pedicle graft provides reasonable results in healing congenital pseudarthrosis of the tibia. Patients should be monitored for the sequelae of this condition, including nonunion, refracture, shortening, and angular deformity, and treated accordingly. Therapeutic Level IV.

Three descending interneurons reporting deviation from course in the locust. I. Anatomy.

PubMed

Griss, C; Rowell, C H

1986-06-01

Three descending brain interneurons (DNI, DNM, DNC) are described from Locusta migratoria. All are paired, dorsally situated neurons, with soma in the protocerebrum, input dendrites in the proto- and deuterocerebrum, and a single axon running to the metathoracic ganglion and sometimes further. In DNI the soma and all cerebral arborizations lie ipsilateral to the axon. Discrete regions of arborization lie in the ipsilateral and medial ocellar tracts, the midprotocerebrum and the deuterocerebrum. In the other ganglia the axon branches only ipsilaterally, principally laterally in the flight motor neuropil but also towards the midline. DNC is similarly organized to DNI, but the cell crosses the midline in the brain. Soma, the single projection into a lateral ocellar tract, and the midprotocerebral arborization all lie contralateral to the axon. The deuterocerebral arborization is, however, ipsilateral to the axon. The pattern of projections in the remaining ganglia resembles that of DNI. The soma and all cerebral arborizations of DNM lie ipsilateral to the axon. The arborization is only weakly subdivided into protocerebral, deuterocerebral and medial ocellar tract regions. In the remaining ganglia the arborization extends bilaterally to similar areas of both left and right flight motor neuropil. A table of synonymy is given, equating the various names used for these neurons by previous authors. The morphology correlates well with the known input and output connections. They respond physiologically to deviations from the normal flight posture mediated by ocelli, eyes and wind hairs and connect to the thoracic flight apparatus.

Speed-Dependent Contribution of Callosal Pathways to Ipsilateral Movements

PubMed Central

Tazoe, Toshiki

2013-01-01

Transcallosal inhibitory interactions between primary motor cortices are important to suppress unintended movements in a resting limb during voluntary activation of the contralateral limb. The functional contribution of transcallosal inhibition targeting the voluntary active limb remains unknown. Using transcranial magnetic stimulation, we examined transcallosal inhibition [by measuring interhemispheric inhibition (IHI) and the ipsilateral silent period (iSP)] in the preparatory and execution phases of isotonic slower self-paced and ballistic movements performed by the ipsilateral index finger into abduction and the elbow into flexion in intact humans. We demonstrate decreased IHI in the preparatory phase of self-paced and ballistic index finger and elbow movements compared to rest; the decrease in IHI was larger during ballistic than self-paced movements. In contrast, in the execution phase, IHI and the iSP increased during ballistic compared to self-paced movements. Transcallosal inhibition was negatively correlated with reaction times in the preparatory phase and positively correlated with movement amplitude in the execution phase. Together, our results demonstrate a widespread contribution of transcallosal inhibition to ipsilateral movements of different speeds with a functional role during rapid movements; at faster speeds, decreased transcallosal inhibition in the preparatory phase may contribute to start movements rapidly, while the increase in the execution phase may contribute to stop the movement. We argue that transcallosal pathways enable signaling of the time of discrete behavioral events during ipsilateral movements, which is amplified by the speed of a movement. PMID:24107950

Reading performance after vision rehabilitation of subjects with homonymous visual field defects.

PubMed

Gall, Carolin; Sabel, Bernhard A

2012-12-01

To examine whether increased visual functioning after vision-restoration training (VRT) coincides with improved reading abilities. Prospective noncontrolled open-label trial. Controlled laboratory setting for all diagnostic procedures that were conducted before and after 6 months of home-based VRT with telemedicine support. Eleven subjects who had experienced a posterior-parietal stroke and have homonymous visual field defects. Six months of VRT (1 hour daily repeated light stimulation in the partially damaged visual field). VRT outcome measures were the number of detected light stimuli in eye-tracker controlled high-resolution perimetry and the spared visual field within the affected hemifield up to the relative and absolute defect visual field border (square degrees). Enlargements of spared visual field within the affected hemifield were correlated with changes of reading speed after VRT. After VRT, the number of detected light stimuli increased by 5.02 ± 4.31% (mean ± SD; P = .03). The spared visual field up to the relative defect visual field border increased from 18.09 ± 32.35 square degrees before to 137.40 ± 53.32 after VRT (P = .006), as well as for the absolute defect visual field border from 36.95 ± 33.77 square degrees before VRT to 152.02 ± 49.70 after VRT (P = .005). Reading speed increased from 108.95 ± 33.95 words per minute before VRT to 122.26 ± 30.35 after VRT (P = .017), which significantly correlated with increased spared visual field up to the relative defect visual field border (r = 0.73, P = .016). Measures of eye movement variability did not correlate with VRT outcome. VRT improved visual fields in parafoveal areas, which are most relevant for reading. This finding cannot be explained by changes in eye movement behavior. Because of a significant association between improvements of parafoveal vision and reading speed, we propose that patients with homonymous visual field defects who have reading deficits may benefit from visual stimulation by training. Copyright © 2012 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Histogram based analysis of lung perfusion of children after congenital diaphragmatic hernia repair.

PubMed

Kassner, Nora; Weis, Meike; Zahn, Katrin; Schaible, Thomas; Schoenberg, Stefan O; Schad, Lothar R; Zöllner, Frank G

2018-05-01

To investigate a histogram based approach to characterize the distribution of perfusion in the whole left and right lung by descriptive statistics and to show how histograms could be used to visually explore perfusion defects in two year old children after Congenital Diaphragmatic Hernia (CDH) repair. 28 children (age of 24.2±1.7months; all left sided hernia; 9 after extracorporeal membrane oxygenation therapy) underwent quantitative DCE-MRI of the lung. Segmentations of left and right lung were manually drawn to mask the calculated pulmonary blood flow maps and then to derive histograms for each lung side. Individual and group wise analysis of histograms of left and right lung was performed. Ipsilateral and contralateral lung show significant difference in shape and descriptive statistics derived from the histogram (Wilcoxon signed-rank test, p<0.05) on group wise and individual level. Subgroup analysis (patients with vs without ECMO therapy) showed no significant differences using histogram derived parameters. Histogram analysis can be a valuable tool to characterize and visualize whole lung perfusion of children after CDH repair. It allows for several possibilities to analyze the data, either describing the perfusion differences between the right and left lung but also to explore and visualize localized perfusion patterns in the 3D lung volume. Subgroup analysis will be possible given sufficient sample sizes. Copyright © 2017 Elsevier Inc. All rights reserved.

Multiple forebrain systems converge on motor neurons innervating the thyroarytenoid muscle

PubMed Central

Van Daele, Douglas J.; Cassell, Martin D.

2009-01-01

The present study investigated the central connections of motor neurons innervating the thyroarytenoid laryngeal muscle that is active in swallowing, respiration and vocalization. In both intact and sympathectomized rats, the pseudorabies virus (PRV) was inoculated into the muscle. After initial infection of laryngomotor neurons in the ipsilateral loose division of the nucleus ambiguous (NA) by 3 days post-inoculation., PRV spread to the ipsilateral compact portion of the NA, the central and intermediate divisions of the nucleus tractus solitarii (NTS), the Botzinger complex, and the parvocellular reticular formation by 4 days. Infection was subsequently expanded to include the ipsilateral granular and dysgranular parietal insular cortex, the ipsilateral medial division of the central nucleus of the amygdala, the lateral, paraventricular, ventrolateral and medial preoptic nuclei of the hypothalamus (generally bilaterally), the lateral periaqueductal gray, the A7 and oral and caudal pontine nuclei. At the latest time points sampled post-inoculation (5 days), infected neurons were identified in the ipsilateral agranular insular cortex, the caudal parietal insular cortex, the anterior cingulate cortex, and the contralateral motor cortex. In the amygdala, infection had spread to the lateral central nucleus and the parvocellular portion of the basolateral nucleus. Hypothalamic infection was largely characterized by an increase in the number of infected cells in earlier infected regions though the posterior, dorsomedial, tuberomammillary and mammillary nuclei contained infected cells. Comparison with previous connectional data suggest PRV followed three interconnected systems originating in the forebrain; a bilateral system including the ventral anterior cingulate cortex, periaqueductal gray and ventral respiratory group; an ipsilateral system involving the parietal insular cortex, central nucleus of the amygdala and parvicellular reticular formation, and a minor contralateral system originating in motor cortex. Hypothalamic innervation involved several functionally specific nuclei. Overall, the data imply complex central nervous system control over the multi-functional thyroarytenoid muscle.[297 words] PMID:19426785

Ipsilateral pedicled TRAM flaps: the safer alternative?

PubMed

Clugston, P A; Gingrass, M K; Azurin, D; Fisher, J; Maxwell, G P

2000-01-01

Transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction has become a commonly performed procedure in the 1990s. The original description of the procedure was that of an ipsilaterally based pedicle procedure. Concerns about potential folding of the pedicle with possible compromise of the vascular supply led many surgeons to prefer the contralateral pedicle. Subsequently, there have been several large clinical series of pedicled TRAM flaps showing a relatively high complication rate related to flap vascularity problems. Partial flap necrosis rates in pedicled TRAM series range from 5 to 44 percent. These findings resulted in many centers favoring free TRAM flap breast reconstruction, despite an increase in resource use and negligible differences in complication rates. Ipsilateral pedicle TRAM flap breast reconstruction is not a commonly reported procedure and is reserved for cases for which scars preclude use of the contralateral pedicle. Simplicity and versatility of flap shaping, improved maintenance of the inframammary fold, and lack of disruption of the natural xiphoid hollow give ipsilateral TRAM flaps further advantages. This study reports on a series of 252 consecutive ipsilateral TRAM flap reconstructions in 190 patients. The majority of patients underwent muscle-sparing procedures with preservation of a medial and a lateral strip of rectus muscle. Immediate reconstruction was done in 104 of the 190 patients. Skin-sparing (69 patients) or skin-reduction procedures (21 patients) were used in 90 of the 104 patients (87 percent) undergoing immediate reconstruction. Complication rates were comparable to those of series reported for contralateral TRAM flaps, except that partial flap necrosis (2.0 percent) was less in this series. Risk factors were analyzed with regard to the most common complications seen in this study. Ipsilateral TRAM flap breast reconstruction is our preferred method, if available, because we believe that it has several advantages over the contralateral pedicled TRAM and this report suggests a lower partial flap necrosis rate than previously reported.

Early detection of secondary damage in ipsilateral thalamus after acute infarction at unilateral corona radiata by diffusion tensor imaging and magnetic resonance spectroscopy

PubMed Central

2011-01-01

Background Traditional magnetic resonance (MR) imaging can identify abnormal changes in ipsilateral thalamus in patients with unilateral middle cerebral artery (MCA) infarcts. However, it is difficult to demonstrate these early changes quantitatively. Diffusion tensor imaging (DTI) and proton magnetic resonance spectroscopy (MRS) are potentially sensitive and quantitative methods of detection in examining changes of tissue microstructure and metabolism. In this study, We used both DTI and MRS to examine possible secondary damage of thalamus in patients with corona radiata infarction. Methods Twelve patients with unilateral corona radiata infarction underwent MR imaging including DTI and MRS at one week (W1), four weeks (W4), and twelve weeks (W12) after onset of stroke. Twelve age-matched controls were imaged. Mean diffusivity (MD), fractional anisotropy (FA), N-acetylaspartate (NAA), choline(Cho), and creatine(Cr) were measured in thalami. Results T1-weighted fluid attenuation inversion recovery (FLAIR), T2-weighted, and T2-FLAIR imaging showed an infarct at unilateral corona radiate but no other lesion in each patient brain. In patients, MD was significantly increased at W12, compared to W1 and W4 (all P< 0.05). NAA was significantly decreased at W4 compared to W1, and at W12 compared to W4 (all P< 0.05) in the ipsilateral thalamus. There was no significant change in FA, Cho, or Cr in the ipsilateral thalamus from W1 to W12. Spearman's rank correlation analysis revealed a significant negative correlation between MD and the peak area of NAA, Cho, and Cr at W1, W4, and W12 and a significant positive correlation of FA with NAA at W1. Conclusions These findings indicate that DTI and MRS can detect the early changes indicating secondary damage in the ipsilateral thalamus after unilateral corona radiata infarction. MRS may reveal the progressive course of damage in the ipsilateral thalamus over time. PMID:21542942

GABAergic inputs to the nucleus rotundus (pulvinar inferior) of the pigeon (columba livia).

PubMed

Mpodozis, J; Cox, K; Shimizu, T; Bischof, H J; Woodson, W; Karten, H J

1996-10-14

The avian nucleus rotundus, a nucleus that appears to be homologous to the inferior/ caudal pulvinar of mammals, is the major target of an ascending retino-tecto-thalamic pathway. Further clarification of the inputs to the rotundus and their functional properties will contribute to our understanding of the fundamental role of the ascending tectal inputs to the telencephalon in all vertebrates, including mammals. We found that the rotundus contains a massive plexus of glutamic acid decarboxylase (GAD)-immunoreactive axons using antibodies against GAD. The cells within the rotundus, however, were not immunoreactive for GAD. The retrograde tracer cholera toxin B fragment was injected into the rotundus to establish the location of the afferent neurons and determine the source of the gamma-aminobutyric acid (GABA) inputs into the rotundus. In addition to the recognized bilateral inputs from layer 13 of the tectum, we found intense retrograde labeling of neurons within the ipsilateral nuclei subpretectalis (SP), subpretectalis-caudalis (SPcd), interstitio-pretecto-subpretectalis (IPS), posteroventralis thalami (PV), and reticularis superior thalami (RS). All the neurons of the SP, SPcd, IPS, and PV were intensely GAD-immunoreactive. The neurons of layer 13 of the tectum were not immunoreactive for GAD. Following the destruction of the ipsilateral SP/IPS complex, we found a major reduction in the intensity of the GAD axonal immunoreactivity within the ipsilateral rotundus, but this destruction did not diminish the intensity of the GAD-immunoreactivity within the contralateral rotundus. Our studies indicated that the source of the massive GAD-immunoreactive plexus within the rotundus was from the ipsilateral SP, SPcd, IPS, and PV nuclei. These nuclei, in turn, received ipsilateral tectal input via collaterals of the neurons of layer 13 in the course of their projections upon the rotundus. We suggest that the direct bilateral tecto-rotundal projections are excitatory, whereas the indirect ipsilateral projections from the SP/IPS and PV are mainly inhibitory, possibly acting via a GABA-A receptor.

Using ipsilateral motor signals in the unaffected cerebral hemisphere as a signal platform for brain-computer interfaces in hemiplegic stroke survivors

NASA Astrophysics Data System (ADS)

Bundy, David T.; Wronkiewicz, Mark; Sharma, Mohit; Moran, Daniel W.; Corbetta, Maurizio; Leuthardt, Eric C.

2012-06-01

Brain-computer interface (BCI) systems have emerged as a method to restore function and enhance communication in motor impaired patients. To date, this has been applied primarily to patients who have a compromised motor outflow due to spinal cord dysfunction, but an intact and functioning cerebral cortex. The cortical physiology associated with movement of the contralateral limb has typically been the signal substrate that has been used as a control signal. While this is an ideal control platform in patients with an intact motor cortex, these signals are lost after a hemispheric stroke. Thus, a different control signal is needed that could provide control capability for a patient with a hemiparetic limb. Previous studies have shown that there is a distinct cortical physiology associated with ipsilateral, or same-sided, limb movements. Thus far, it was unknown whether stroke survivors could intentionally and effectively modulate this ipsilateral motor activity from their unaffected hemisphere. Therefore, this study seeks to evaluate whether stroke survivors could effectively utilize ipsilateral motor activity from their unaffected hemisphere to achieve this BCI control. To investigate this possibility, electroencephalographic (EEG) signals were recorded from four chronic hemispheric stroke patients as they performed (or attempted to perform) real and imagined hand tasks using either their affected or unaffected hand. Following performance of the screening task, the ability of patients to utilize a BCI system was investigated during on-line control of a one-dimensional control task. Significant ipsilateral motor signals (associated with movement intentions of the affected hand) in the unaffected hemisphere, which were found to be distinct from rest and contralateral signals, were identified and subsequently used for a simple online BCI control task. We demonstrate here for the first time that EEG signals from the unaffected hemisphere, associated with overt and imagined movements of the affected hand, can enable stroke survivors to control a one-dimensional computer cursor rapidly and accurately. This ipsilateral motor activity enabled users to achieve final target accuracies between 68% and 91% within 15 min. These findings suggest that ipsilateral motor activity from the unaffected hemisphere in stroke survivors could provide a physiological substrate for BCI operation that can be further developed as a long-term assistive device or potentially provide a novel tool for rehabilitation.

Reticular Formation Connections Underlying Horizontal Gaze: The Central Mesencephalic Reticular Formation (cMRF) as a Conduit for the Collicular Saccade Signal

PubMed Central

Wang, Niping; Perkins, Eddie; Zhou, Lan; Warren, Susan; May, Paul J.

2017-01-01

The central mesencephalic reticular formation (cMRF) occupies much of the core of the midbrain tegmentum. Physiological studies indicate that it is involved in controlling gaze changes, particularly horizontal saccades. Anatomically, it receives input from the ipsilateral superior colliculus (SC) and it has downstream projections to the brainstem, including the horizontal gaze center located in the paramedian pontine reticular formation (PPRF). Consequently, it has been hypothesized that the cMRF plays a role in the spatiotemporal transformation needed to convert spatially coded collicular saccade signals into the temporally coded signals utilized by the premotor neurons of the horizontal gaze center. In this study, we used neuroanatomical tracers to examine the patterns of connectivity of the cMRF in macaque monkeys in order to determine whether the circuit organization supports this hypothesis. Since stimulation of the cMRF produces contraversive horizontal saccades and stimulation of the horizontal gaze center produces ipsiversive saccades, this would require an excitatory cMRF projection to the contralateral PPRF. Injections of anterograde tracers into the cMRF did produce labeled terminals within the PPRF. However, the terminations were denser ipsilaterally. Since the PPRF located contralateral to the movement direction is generally considered to be silent during a horizontal saccade, we then tested the hypothesis that this ipsilateral reticuloreticular pathway might be inhibitory. The ultrastructure of ipsilateral terminals was heterogeneous, with some displaying more extensive postsynaptic densities than others. Postembedding immunohistochemistry for gamma-aminobutyric acid (GABA) indicated that only a portion (35%) of these cMRF terminals are GABAergic. Dual tracer experiments were undertaken to determine whether the SC provides input to cMRF reticuloreticular neurons projecting to the ipsilateral pons. Retrogradely labeled reticuloreticular neurons were predominantly distributed in the ipsilateral cMRF. Anterogradely labeled tectal terminals were observed in close association with a portion of these retrogradely labeled reticuloreticular neurons. Taken together, these results suggest that the SC does have connections with reticuloreticular neurons in the cMRF. However, the predominantly excitatory nature of the ipsilateral reticuloreticular projection argues against the hypothesis that this cMRF pathway is solely responsible for producing a spatiotemporal transformation of the collicular saccade signal. PMID:28487639

Asymptomatic embolisation for prediction of stroke in the Asymptomatic Carotid Emboli Study (ACES): a prospective observational study

PubMed Central

Markus, Hugh S; King, Alice; Shipley, Martin; Topakian, Raffi; Cullinane, Marisa; Reihill, Sheila; Bornstein, Natan M; Schaafsma, Arjen

2010-01-01

Summary Background Whether surgery is beneficial for patients with asymptomatic carotid stenosis is controversial. Better methods of identifying patients who are likely to develop stroke would improve the risk–benefit ratio for carotid endarterectomy. We aimed to investigate whether detection of asymptomatic embolic signals by use of transcranial doppler (TCD) could predict stroke risk in patients with asymptomatic carotid stenosis. Methods The Asymptomatic Carotid Emboli Study (ACES) was a prospective observational study in patients with asymptomatic carotid stenosis of at least 70% from 26 centres worldwide. To detect the presence of embolic signals, patients had two 1 h TCD recordings from the ipsilateral middle cerebral artery at baseline and one 1 h recording at 6, 12, and 18 months. Patients were followed up for 2 years. The primary endpoint was ipsilateral stroke and transient ischaemic attack. All recordings were analysed centrally by investigators masked to patient identity. Findings 482 patients were recruited, of whom 467 had evaluable recordings. Embolic signals were present in 77 of 467 patients at baseline. The hazard ratio for the risk of ipsilateral stroke and transient ischaemic attack from baseline to 2 years in patients with embolic signals compared with those without was 2·54 (95% CI 1·20–5·36; p=0·015). For ipsilateral stroke alone, the hazard ratio was 5·57 (1·61–19·32; p=0·007). The absolute annual risk of ipsilateral stroke or transient ischaemic attack between baseline and 2 years was 7·13% in patients with embolic signals and 3·04% in those without, and for ipsilateral stroke was 3·62% in patients with embolic signals and 0·70% in those without. The hazard ratio for the risk of ipsilateral stroke and transient ischaemic attack for patients who had embolic signals on the recording preceding the next 6-month follow-up compared with those who did not was 2·63 (95% CI 1·01–6·88; p=0·049), and for ipsilateral stroke alone the hazard ratio was 6·37 (1·59–25·57; p=0·009). Controlling for antiplatelet therapy, degree of stenosis, and other risk factors did not alter the results. Interpretation Detection of asymptomatic embolisation on TCD can be used to identify patients with asymptomatic carotid stenosis who are at a higher risk of stroke and transient ischaemic attack, and also those with a low absolute stroke risk. Assessment of the presence of embolic signals on TCD might be useful in the selection of patients with asymptomatic carotid stenosis who are likely to benefit from endarterectomy. Funding British Heart Foundation. PMID:20554250

Extracellular glutamate and other amino acids in experimental intracerebral hemorrhage: an in vivo microdialysis study.

PubMed

Qureshi, Adnan I; Ali, Zulfiqar; Suri, M Fareed K; Shuaib, Asfhaq; Baker, Glen; Todd, Kathryn; Guterman, Lee R; Hopkins, L Nelson

2003-05-01

To determine whether extracellular concentrations of glutamate and other amino acids are significantly elevated after intracerebral hemorrhage and, if so, the temporal characteristics of these changes. Although the role of excitotoxic amino acids, particularly that of glutamate, has been described in ischemic stroke and head trauma, no information exists regarding their possible contribution to the pathogenesis of neuronal injury in intracerebral hemorrhage. Prospective, controlled, laboratory trial. Animal research laboratory. Sixteen anesthetized New Zealand rabbits. We introduced intracerebral hemorrhage in each of eight anesthetized New Zealand rabbits by injecting 0.4 mL of autologous blood under arterial pressure into the deep gray matter of the cerebrum. Extracellular fluid samples were collected from the perihematoma region and contralateral (right) hemisphere by in vivo microdialysis at 30-min intervals for 6 hrs. Corresponding samples were similarly collected from both hemispheres in each of eight control animals that underwent needle placement without introduction of a hematoma. Concentrations of amino acids (glutamate, aspartate, asparagine, glycine, taurine, and gamma-aminobutyric acid) in the samples were measured by use of high-pressure liquid chromatography with fluorescence detection. Glutamate concentrations (mean +/- sem) were significantly higher in the hemisphere ipsilateral to the hematoma than in the contralateral hemisphere (92 +/- 22 pg/microL vs. 22 +/- 6 pg/microL) at 30 mins after hematoma creation. A significant increase was observed at 30 mins posthematoma creation in the hemisphere ipsilateral to the hematoma compared with the baseline value. A nonsignificant increase in glutamate concentration persisted in the hemisphere ipsilateral to the hematoma, ranging from 134% to 187% of baseline value between 1 and 5 hrs after hematoma creation. In the hemisphere ipsilateral to the hematoma, a three-fold increase in the concentration of glycine was observed at 30 mins after hematoma creation compared with the baseline level (890 +/- 251 pg/microL vs. 291 +/- 73 pg/microL). There was a significant difference between the hemisphere ipsilateral to the hematoma compared with the ipsilateral (corresponding) hemisphere of the control group at 30 mins posthematoma (890 +/- 251 pg/microL vs. 248 +/- 66 pg/microL). A similar transient increase was observed in taurine and asparagine concentrations at 30 mins after hematoma creation, compared with baseline measurements. Taurine concentrations in the hemisphere ipsilateral to the hematoma were significantly higher than the ipsilateral hemisphere of the control group (622 +/- 180 pg/microL vs. 202 +/- 64 pg/microL) at 30 mins after hematoma creation. The present study suggests that glutamate and other amino acids accumulate transiently in extracellular fluids in the perihematoma region during the early period of intracerebral hemorrhage. The exact role of these amino acids in the pathogenesis of neuronal injury observed in intracerebral hemorrhage needs to be defined.

Visual field defects may not affect safe driving.

PubMed

Dow, Jamie

2011-10-01

In Quebec a driver whose acquired visual field defect renders them ineligible for a driver's permit renewal may request an exemption from the visual field standard by demonstrating safe driving despite the defect. For safety reasons it was decided to attempt to identify predictors of failure on the road test in order to avoid placing driving evaluators in potentially dangerous situations when evaluating drivers with visual field defects. During a 4-month period in 2009 all requests for exemptions from the visual field standard were collected and analyzed. All available medical and visual field data were collated for 103 individuals, of whom 91 successfully completed the evaluation process and obtained a waiver. The collated data included age, sex, type of visual field defect, visual field characteristics, and concomitant medical problems. No single factor, or combination of factors, could predict failure of the road test. All 5 failures of the road test had cognitive problems but 6 of the successful drivers also had known cognitive problems. Thus, cognitive problems influence the risk of failure but do not predict certain failure. Most of the applicants for an exemption were able to complete the evaluation process successfully, thereby demonstrating safe driving despite their handicap. Consequently, jurisdictions that have visual field standards for their driving permit should implement procedures to evaluate drivers with visual field defects that render them unable to meet the standard but who wish to continue driving.

21 CFR 886.1360 - Visual field laser instrument.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Visual field laser instrument. 886.1360 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1360 Visual field laser instrument. (a) Identification. A visual field laser instrument is an AC-powered device intended to provide...

21 CFR 886.1360 - Visual field laser instrument.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Visual field laser instrument. 886.1360 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1360 Visual field laser instrument. (a) Identification. A visual field laser instrument is an AC-powered device intended to provide...

21 CFR 886.1360 - Visual field laser instrument.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Visual field laser instrument. 886.1360 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1360 Visual field laser instrument. (a) Identification. A visual field laser instrument is an AC-powered device intended to provide...

21 CFR 886.1360 - Visual field laser instrument.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Visual field laser instrument. 886.1360 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1360 Visual field laser instrument. (a) Identification. A visual field laser instrument is an AC-powered device intended to provide...

Pyramidal tract stimulation restores normal corticospinal tract connections and visuomotor skill after early postnatal motor cortex activity blockade

PubMed Central

Salimi, I; Friel, KM; Martin, JH

2008-01-01

Motor development depends on forming specific connections between the corticospinal tract (CST) and the spinal cord. Blocking CST activity in kittens during the critical period for establishing connections with spinal motor circuits results in permanent impairments in connectivity and function. The changes in connections are consistent with the hypothesis that the inactive tract is less competitive in developing spinal connections than the active tract. In this study we tested the competition hypothesis by determining if activating CST axons, after prior silencing during the critical period, abrogated development of aberrant corticospinal connections and motor impairments. In kittens, we inactivated motor cortex by muscimol infusion between postnatal weeks 5-7. We next electrically stimulated CST axons in the medullary pyramid 2.5 hours daily, between weeks 7-10. In controls (n=3), CST terminations were densest within the contralateral deeper, premotor, spinal layers. After prior inactivation (n=3), CST terminations were densest within the dorsal, somatic sensory, layers. There were more ipsilateral terminations from the active tract. During visually guided locomotion, there was a movement endpoint impairment. Stimulation after inactivation (n=6) resulted in significantly fewer terminations in the sensory layers and more in the premotor layers, and fewer ipsilateral connections from active cortex. Chronic stimulation reduced the current threshold for evoking contralateral movements by pyramidal stimulation, suggesting strengthening of connections. Importantly, stimulation significantly improved stepping accuracy. These findings show the importance of activity-dependent processes in specifying CST connections. They also provide a strategy for harnessing activity to rescue CST axons at risk of developing aberrant connections after CNS injury. PMID:18632946

An intact action-perception coupling depends on the integrity of the cerebellum.

PubMed

Christensen, Andrea; Giese, Martin A; Sultan, Fahad; Mueller, Oliver M; Goericke, Sophia L; Ilg, Winfried; Timmann, Dagmar

2014-05-07

It is widely accepted that action and perception in humans functionally interact on multiple levels. Moreover, areas originally suggested to be predominantly motor-related, as the cerebellum, are also involved in action observation. However, as yet, few studies provided unequivocal evidence that the cerebellum is involved in the action perception coupling (APC), specifically in the integration of motor and multisensory information for perception. We addressed this question studying patients with focal cerebellar lesions in a virtual-reality paradigm measuring the effect of action execution on action perception presenting self-generated movements as point lights. We measured the visual sensitivity to the point light stimuli based on signal detection theory. Compared with healthy controls cerebellar patients showed no beneficial influence of action execution on perception indicating deficits in APC. Applying lesion symptom mapping, we identified distinct areas in the dentate nucleus and the lateral cerebellum of both hemispheres that are causally involved in APC. Lesions of the right ventral dentate, the ipsilateral motor representations (lobules V/VI), and most interestingly the contralateral posterior cerebellum (lobule VII) impede the benefits of motor execution on perception. We conclude that the cerebellum establishes time-dependent multisensory representations on different levels, relevant for motor control as well as supporting action perception. Ipsilateral cerebellar motor representations are thought to support the somatosensory state estimate of ongoing movements, whereas the ventral dentate and the contralateral posterior cerebellum likely support sensorimotor integration in the cerebellar-parietal loops. Both the correct somatosensory as well as the multisensory state representations are vital for an intact APC.

Altered neural activity and emotions following right middle cerebral artery stroke.

PubMed

Paradiso, Sergio; Anderson, Beth M; Boles Ponto, Laura L; Tranel, Daniel; Robinson, Robert G

2011-01-01

Stroke of the right MCA is common. Such strokes often have consequences for emotional experience, but these can be subtle. In such cases diagnosis is difficult because emotional awareness (limiting reporting of emotional changes) may be affected. The present study sought to clarify the mechanisms of altered emotion experience after right MCA stroke. It was predicted that after right MCA stroke the anterior cingulate cortex (ACC), a brain region concerned with emotional awareness, would show reduced neural activity. Brain activity during presentation of emotional stimuli was measured in 6 patients with stable stroke, and in 12 age- and sex-matched nonlesion comparisons using positron emission tomography and the [(15)O]H(2)O autoradiographic method. MCA stroke was associated with weaker pleasant experience and decreased activity ipsilaterally in the ACC. Other regions involved in emotional processing including thalamus, dorsal and medial prefrontal cortex showed reduced activity ipsilaterally. Dorsal and medial prefrontal cortex, association visual cortex and cerebellum showed reduced activity contralaterally. Experience from unpleasant stimuli was unaltered and was associated with decreased activity only in the left midbrain. Right MCA stroke may reduce experience of pleasant emotions by altering brain activity in limbic and paralimbic regions distant from the area of direct damage, in addition to changes due to direct tissue damage to insula and basal ganglia. The knowledge acquired in this study begins to explain the mechanisms underlying emotional changes following right MCA stroke. Recognizing these changes may improve diagnoses, management and rehabilitation of right MCA stroke victims. Copyright © 2011 National Stroke Association. Published by Elsevier Inc. All rights reserved.

SU-F-T-85: Energy Modulated Electron Postmastectomy Unreconstructed (PU) Chest Wall (CW) Irradiation Technique to Achieve Heart Sparing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, L; Ballangrud, A; Mechalakos, J

Purpose: For left-sided PU patients requiring CW and nodal irradiation, sometimes partial wide tangents (PWT) are not feasible due to abnormal chest wall contour or heart position close to the anterior chest wall or unusual wide excision scar. We developed an energy modulated electron chest wall irradiation technique that will achieve heart sparing. Methods: Ten left-sided PU patients were selected for this dosimetry study. If PWT were used, the amount of the ipsilateral lung would be ranged 3.4 to 4.4 cm, and the amount of heart would be ranged 1.3 to 3.8 cm. We used electron paired fields that matchedmore » on the skin to achieve dose conformity to the chest wall. The enface electron fields were designed at extended SSD from a single isocenter and gantry angle with different energy beams using different cutout. Lower energy was used in the central chest wall part and higher energy was used in the periphery of the chest wall. Bolus was used for the electron fields to ensure adequate skin dose coverage. The electron fields were matched to the photon supra-clavicle field in the superior region. Daily field junctions were used to feather the match lines between all the fields. Target volumes and normal tissues were drawn according to institutional protocols. Prescription dose was 2Gy per fraction for a total 50Gy. Dose calculations were done with Eclipse EMC-11031 for Electron and AAA-11031 for photons. Results: Six patients were planned using 6/9MeV, three using 9/12MeV and one 6/12MeV. Target volumes achieved adequate coverage. For heart, V30Gy, V20Gy and Mean Dose were 0.6%±0.6%, 2.7%±1.7%, and 3.0Gy±0.8Gy respectively. For ipsilateral lung, V50Gy, V20Gy, V10Gy and V5Gy were 0.9%±1.1%, 34.3%±5.1%, 51.6%±6.3% and 64.1%±7.5% respectively. Conclusion: For left-sided PU patients with unusual anatomy, energy modulated electron CW irradiation technique can achieve heart sparing with acceptable lung dose.« less

Management of central venous gradient using excimer laser lead extraction of chronic indwelling pacemaker leads in the setting of ipsilateral arteriovenous fistula.

PubMed

Ramirez, Alexies; Gentlesk, Philip J; Peele, Mark E; Eckart, Robert E

2012-07-01

Device therapy is becoming common in those patients with renal insufficiency. Coexisting need for arteriovenous (AV) fistula placement is often contemplated relative to device placement. We describe the excimer laser lead extraction of a malfunctioning chronic atrial pacemaker lead ipsilateral to an AV fistula.

Multifocal synchronous ipsilateral Warthin tumors: case report and review of the literature.

PubMed

Hall, Joseph E; Statham, Melissa McCarty; Sheridan, Rachel M; Wilson, Keith M

2010-09-01

We report a case of a 73-year-old woman who presented with an enlarging superficial parotid mass, a concomitant ipsilateral deep-lobe parotid mass, and associated upper jugular lymphadenopathy. The clinical presentation and radiographic imaging were suggestive of malignancy, and the patient was treated with total parotidectomy with upper jugular lymph node sampling. Pathologic examination revealed two distinct masses, one in the superficial lobe and one in the deep lobe of the parotid gland, both consistent with synchronous Warthin tumors. Analysis of the upper jugular lymph nodes was consistent with reactive lymphoid hyperplasia. Although the true incidence of multicentricity in ipsilateral Warthin tumors may be underappreciated and underreported, this entity should remain in the differential diagnosis for unilateral parotid masses.

Retention of retinal axon collateral is responsible for induced ipsilateral retinotectal projections in adult goldfish.

PubMed

Sharma, S C; Tsai, C

1991-01-01

In normal goldfish, optic axons innervate only the contralateral optic tectum. When one eye was enucleated and the optic nerve of the other eye crushed, the regenerating optic axons innervated both optic tecta. We studied the presence of bilaterally projecting retinal ganglion cells by double retrograde cell labeling methods using Nuclear Yellow and True Blue dyes. About 10% of the retinal ganglion cells were double labeled and these cells were found throughout the retina. In addition, HRP application to the ipsilateral tectum revealed retrogradely-labeled retinal ganglion cells of all morphological types. These results suggest that induced ipsilateral projections are formed by regenerating axon collaterals and that all cell types are involved in the generation of normal mirror image typography.

Morning glory disk anomaly with ipsilateral capillary hemangioma, agenesis of the internal carotid artery, and Horner syndrome: a variant of PHACES syndrome?

PubMed

Puvanachandra, Narman; Heran, Manraj K; Lyons, Christopher J

2008-10-01

We describe a 6-week-old girl with a right upper lid capillary hemangioma, ipsilateral morning glory disk anomaly, microphthalmos, Mittendorf dot, and Horner syndrome. The ipsilateral internal carotid artery was also found to be absent. To our knowledge, this is the first patient to be reported with this group of findings. We suggest that this represents an overlap between morning glory disk and intracranial vascular abnormalities, a recognized association, and PHACES syndrome (posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye, and sternal abnormalities). We discuss the common embryological basis for these abnormalities, which point to a widespread but highly variable disorder of mesodermal differentiation.

[Neglected ipsilateral simultaneous ruptures of patellar and quadriceps tendon].

PubMed

Karahasanoğlu, İlker; Yoloğlu, Osman; Kerimoğlu, Servet; Turhan, Ahmet Uğur

2015-01-01

Neglected patellar and quadriceps tendon rupture is a rare injury, but ipsilateral simultaneous patellar and quadriceps tendon rupture was not described in the literature to our knowledge. In this article, we report a 40-year-old healthy male patient with neglected ipsilateral patellar and quadriceps tendon ruptures treated by peroneus longus tendon autograft. Patient had received some conservative and surgical treatments for patellar fracture before applying to our clinic. After our treatment using peroneus longus autograft and interference nails, patient was immobilized for six weeks in cylindrical cast. Flexion exercises and full weight bearing were started after cast removal. Patient had no complaint at postoperative second year. Patient was a neglected case. Surgical repair and early rehabilitation enabled us to achieve a satisfactory outcome.

Regional thalamic neuropathology in patients with hippocampal sclerosis and epilepsy: A postmortem study

PubMed Central

Sinjab, Barah; Martinian, Lillian; Sisodiya, Sanjay M; Thom, Maria

2013-01-01

Purpose Clinical, experimental, and neuroimaging data all indicate that the thalamus is involved in the network of changes associated with temporal lobe epilepsy (TLE), particularly in association with hippocampal sclerosis (HS), with potential roles in seizure initiation and propagation. Pathologic changes in the thalamus may be a result of an initial insult, ongoing seizures, or retrograde degeneration through reciprocal connections between thalamic and limbic regions. Our aim was to carry out a neuropathologic analysis of the thalamus in a postmortem (PM) epilepsy series, to assess the distribution, severity, and nature of pathologic changes and its association with HS. Methods Twenty-four epilepsy PM cases (age range 25–87 years) and eight controls (age range 38–85 years) were studied. HS was classified as unilateral (UHS, 11 cases), bilateral (BHS, 4 cases) or absent (No-HS, 9 cases). Samples from the left and right sides of the thalamus were stained with cresyl violet (CV), and for glial firbillary acidic protein (GFAP) and synaptophysin. Using image analysis, neuronal densities (NDs) or field fraction staining values (GFAP, synaptophysin) were measured in four thalamic nuclei: anteroventral nucleus (AV), lateral dorsal nucleus (LD), mediodorsal nucleus (MD), and ventrolateral nucleus (VL). The results were compared within and between cases. Key Findings The severity, nature, and distribution of thalamic pathology varied between cases. A pattern that emerged was a preferential involvement of the MD in UHS cases with a reduction in mean ND ipsilateral to the side of HS (p = 0.05). In UHS cases, greater field fraction values for GFAP and lower values for synaptophysin and ND were seen in the majority of cases in the MD ipsilateral to the side of sclerosis compared to other thalamic nuclei. In addition, differences in the mean ND between classical HS, atypical HS, and No-HS cases were noted in the ipsilateral MD (p < 0.05), with lower values observed in HS. Significance Our study demonstrates that stereotypical pathologic changes, as seen in HS, are not clearly defined in the thalamus. This may be partly explained by the heterogeneity of our PM study group. With quantitation, there is some evidence for preferential involvement of the MD, suggesting a potential role in TLE, which requires further investigation. PMID:24138281

38 CFR 4.75 - General considerations for evaluating visual impairment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... refraction), visual field, and muscle function. (b) Examination for visual impairment. The examination must.... Examinations of visual fields or muscle function will be conducted only when there is a medical indication of disease or injury that may be associated with visual field defect or impaired muscle function. Unless...

38 CFR 4.75 - General considerations for evaluating visual impairment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... refraction), visual field, and muscle function. (b) Examination for visual impairment. The examination must.... Examinations of visual fields or muscle function will be conducted only when there is a medical indication of disease or injury that may be associated with visual field defect or impaired muscle function. Unless...

38 CFR 4.75 - General considerations for evaluating visual impairment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... refraction), visual field, and muscle function. (b) Examination for visual impairment. The examination must.... Examinations of visual fields or muscle function will be conducted only when there is a medical indication of disease or injury that may be associated with visual field defect or impaired muscle function. Unless...

Optic nerve dysfunction during gravity inversion. Visual field abnormalities.

PubMed

Sanborn, G E; Friberg, T R; Allen, R

1987-06-01

Inversion in a head-down position (gravity inversion) results in an intraocular pressure of 35 to 40 mm Hg in normal subjects. We used computerized static perimetry to measure the visual fields of normal subjects during gravity inversion. There were no visual field changes in the central 6 degrees of the visual field compared with the baseline (preinversion) values. However, when the central 30 degrees of the visual field was tested, reversible visual field defects were found in 11 of 19 eyes. We believe that the substantial elevation of intraocular pressure during gravity inversion may pose potential risks to the eyes, and we recommend that inversion for extended periods of time be avoided.

Multifield-graphs: an approach to visualizing correlations in multifield scalar data.

PubMed

Sauber, Natascha; Theisel, Holger; Seidel, Hans-Peter

2006-01-01

We present an approach to visualizing correlations in 3D multifield scalar data. The core of our approach is the computation of correlation fields, which are scalar fields containing the local correlations of subsets of the multiple fields. While the visualization of the correlation fields can be done using standard 3D volume visualization techniques, their huge number makes selection and handling a challenge. We introduce the Multifield-Graph to give an overview of which multiple fields correlate and to show the strength of their correlation. This information guides the selection of informative correlation fields for visualization. We use our approach to visually analyze a number of real and synthetic multifield datasets.

Mood Modulates Auditory Laterality of Hemodynamic Mismatch Responses during Dichotic Listening

PubMed Central

Schock, Lisa; Dyck, Miriam; Demenescu, Liliana R.; Edgar, J. Christopher; Hertrich, Ingo; Sturm, Walter; Mathiak, Klaus

2012-01-01

Hemodynamic mismatch responses can be elicited by deviant stimuli in a sequence of standard stimuli even during cognitive demanding tasks. Emotional context is known to modulate lateralized processing. Right-hemispheric negative emotion processing may bias attention to the right and enhance processing of right-ear stimuli. The present study examined the influence of induced mood on lateralized pre-attentive auditory processing of dichotic stimuli using functional magnetic resonance imaging (fMRI). Faces expressing emotions (sad/happy/neutral) were presented in a blocked design while a dichotic oddball sequence with consonant-vowel (CV) syllables in an event-related design was simultaneously administered. Twenty healthy participants were instructed to feel the emotion perceived on the images and to ignore the syllables. Deviant sounds reliably activated bilateral auditory cortices and confirmed attention effects by modulation of visual activity. Sad mood induction activated visual, limbic and right prefrontal areas. A lateralization effect of emotion-attention interaction was reflected in a stronger response to right-ear deviants in the right auditory cortex during sad mood. This imbalance of resources may be a neurophysiological correlate of laterality in sad mood and depression. Conceivably, the compensatory right-hemispheric enhancement of resources elicits increased ipsilateral processing. PMID:22384105

Multisensory integration processing during olfactory-visual stimulation-An fMRI graph theoretical network analysis.

PubMed

Ripp, Isabelle; Zur Nieden, Anna-Nora; Blankenagel, Sonja; Franzmeier, Nicolai; Lundström, Johan N; Freiherr, Jessica

2018-05-07

In this study, we aimed to understand how whole-brain neural networks compute sensory information integration based on the olfactory and visual system. Task-related functional magnetic resonance imaging (fMRI) data was obtained during unimodal and bimodal sensory stimulation. Based on the identification of multisensory integration processing (MIP) specific hub-like network nodes analyzed with network-based statistics using region-of-interest based connectivity matrices, we conclude the following brain areas to be important for processing the presented bimodal sensory information: right precuneus connected contralaterally to the supramarginal gyrus for memory-related imagery and phonology retrieval, and the left middle occipital gyrus connected ipsilaterally to the inferior frontal gyrus via the inferior fronto-occipital fasciculus including functional aspects of working memory. Applied graph theory for quantification of the resulting complex network topologies indicates a significantly increased global efficiency and clustering coefficient in networks including aspects of MIP reflecting a simultaneous better integration and segregation. Graph theoretical analysis of positive and negative network correlations allowing for inferences about excitatory and inhibitory network architectures revealed-not significant, but very consistent-that MIP-specific neural networks are dominated by inhibitory relationships between brain regions involved in stimulus processing. © 2018 Wiley Periodicals, Inc.

Task set induces dynamic reallocation of resources in visual short-term memory.

PubMed

Sheremata, Summer L; Shomstein, Sarah

2017-08-01

Successful interaction with the environment requires the ability to flexibly allocate resources to different locations in the visual field. Recent evidence suggests that visual short-term memory (VSTM) resources are distributed asymmetrically across the visual field based upon task demands. Here, we propose that context, rather than the stimulus itself, determines asymmetrical distribution of VSTM resources. To test whether context modulates the reallocation of resources to the right visual field, task set, defined by memory-load, was manipulated to influence visual short-term memory performance. Performance was measured for single-feature objects embedded within predominantly single- or two-feature memory blocks. Therefore, context was varied to determine whether task set directly predicts changes in visual field biases. In accord with the dynamic reallocation of resources hypothesis, task set, rather than aspects of the physical stimulus, drove improvements in performance in the right- visual field. Our results show, for the first time, that preparation for upcoming memory demands directly determines how resources are allocated across the visual field.

Representation of the visual field in the striate cortex: comparison of MR findings with visual field deficits in organic mercury poisoning (Minamata disease).

PubMed

Korogi, Y; Takahashi, M; Hirai, T; Ikushima, I; Kitajima, M; Sugahara, T; Shigematsu, Y; Okajima, T; Mukuno, K

1997-01-01

To compare MR imaging findings of the striate cortex with visual field deficits in patients with Minamata disease and to reestimate the classical Holmes retinotopic map by using the data obtained from comparing visual field abnormalities with degree of visual cortex atrophy. MR imaging was performed in eight patients with Minamata disease who had been given a full neuroophthalmic examination, including Goldmann dynamic perimetry. The atrophic portions of the calcarine area were measured in the sagittal plane next to the midsagittal image and represented as a percentage of atrophy of the total length of the calcarine fissure. MR findings were compared with results of a visual field test. The visual field test revealed moderate to severe concentric constriction of the visual fields, with central vision ranging from 7 degrees to 42 degrees (mean, 19 degrees). The ventral portion of the calcarine sulcus was significantly dilated on MR images in all patients. A logarithmic correlation was found between the visual field defect and the extent of dilatation of the calcarine fissure. The central 10 degrees and 30 degrees of vision seemed to fill about 20% and 50% of the total surface area of the calcarine cortex, respectively. Visual field deficits in patients with Minamata disease correlated well with MR findings of the striate cortex. Our data were consistent with the classical Holmes retinotopic map.

Reclaiming the Periphery: Automated Kinetic Perimetry for Measuring Peripheral Visual Fields in Patients With Glaucoma.

PubMed

Mönter, Vera M; Crabb, David P; Artes, Paul H

2017-02-01

Peripheral vision is important for mobility, balance, and guidance of attention, but standard perimetry examines only <20% of the entire visual field. We report on the relation between central and peripheral visual field damage, and on retest variability, with a simple approach for automated kinetic perimetry (AKP) of the peripheral field. Thirty patients with glaucoma (median age 68, range 59-83 years; median Mean Deviation -8.0, range -16.3-0.1 dB) performed AKP and static automated perimetry (SAP) (German Adaptive Threshold Estimation strategy, 24-2 test). Automated kinetic perimetry consisted of a fully automated measurement of a single isopter (III.1.e). Central and peripheral visual fields were measured twice on the same day. Peripheral and central visual fields were only moderately related (Spearman's ρ, 0.51). Approximately 90% of test-retest differences in mean isopter radius were < ±4 deg. Relative to the range of measurements in this sample, the retest variability of AKP was similar to that of SAP. Patients with similar central visual field loss can have strikingly different peripheral visual fields, and therefore measuring the peripheral visual field may add clinically valuable information.

Relationship between progression of visual field defect and intraocular pressure in primary open-angle glaucoma.

PubMed

Naito, Tomoko; Yoshikawa, Keiji; Mizoue, Shiro; Nanno, Mami; Kimura, Tairo; Suzumura, Hirotaka; Shiraga, Fumio

2015-01-01

To analyze the relationship between intraocular pressure (IOP) and the progression of visual field defects in Japanese primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) patients. The subjects of the study were patients undergoing treatment for POAG or NTG who had performed visual field tests at least ten times with a Humphrey field analyzer (Swedish interactive thresholding algorithm standard, C30-2 program). The progression of visual field defects was defined by a significantly negative value of the mean deviation slope at the final visual field test during the follow-up period. The relationships between the progression of visual field defects and IOP, as well as other clinical factors, were retrospectively analyzed. A total of 156 eyes of 156 patients were included in the analysis. Significant progression of visual field defects was observed in 70 eyes of 70 patients (44.9%), while no significant progression was evident in 86 eyes of 86 patients (55.1%). The eyes with visual field defect progression had significantly lower baseline IOP (P<0.05), as well as significantly lower IOP reduction rate (P<0.01). The standard deviation of IOP values during follow-up was significantly greater in the eyes with visual field defect progression than in eyes without (P<0.05). Reducing IOP is thought to be useful for Japanese POAG or NTG patients to suppress the progression of visual field defects. In NTG, IOP management should take into account not only achieving the target IOP, but also minimizing the fluctuation of IOP during follow-up period.

Striatal somatotopy and motor responses evoked by acute electrical stimulation of the posterior striatum in rats.

PubMed

Vilela-Filho, Osvaldo; Barros, Breno A; Arruda, Mariana M; Castro, Thaisa S; Souza, Joaquim T; Silva, Delson J; Ferraz, Fernando P; Ragazzo, Paulo C

2014-02-01

Previous experiments suggest that the striatal sensorimotor territory in rats is located in its dorsolateral region, along the rostrocaudal axis, unlike what has been observed in primates. In the present study, electrical stimulation was performed to investigate the degree of participation of the posterior striatum in its motor territory, its somatotopic organization, and the motor responses evoked by stimulation. Twenty-five rats were submitted to stereotactic stimulation of the posterior striatum under general anesthesia, receiving consecutively four different current intensities. The motor responses observed in the different body parts were registered for later comparison. We considered as threshold the smallest of these current intensities able to evoke a motor response. The observed motor responses were qualitatively different for each segment: forepaws: ipsilateral, adduction, and contralateral abduction; hindpaws: ipsilateral, flexion, and contralateral, extension/abduction; trunk, rotation/flexion; and tail, rotation/elevation. High-frequency, small-amplitude distal tremor occurred in the ipsilateral forepaw in 95% of the animals. Progressively larger current intensities were necessary for the induction of motor response in the forepaws, hindpaws, and trunk/tail, in that order. The results allowed us to infer the following posterior striatal somatotopic organization: forepaws, posterolaterally, being the contralateral medial to the ipsilateral; trunk/tail, anteromedially; and hindpaws, in an intermediate position, being the contralateral posterior to the ipsilateral. It is suggested that the tremor and the other observed motor responses derive from the excitation of striatal projection neurons and that the striatum may play an important role in the genesis of essential tremor. © 2013 International Neuromodulation Society.

Electrical stimulation of motor cortex in the uninjured hemisphere after chronic unilateral injury promotes recovery of skilled locomotion through ipsilateral control.

PubMed

Carmel, Jason B; Kimura, Hiroki; Martin, John H

2014-01-08

Partial injury to the corticospinal tract (CST) causes sprouting of intact axons at their targets, and this sprouting correlates with functional improvement. Electrical stimulation of motor cortex augments sprouting of intact CST axons and promotes functional recovery when applied soon after injury. We hypothesized that electrical stimulation of motor cortex in the intact hemisphere after chronic lesion of the CST in the other hemisphere would restore function through ipsilateral control. To test motor skill, rats were trained and tested to walk on a horizontal ladder with irregularly spaced rungs. Eight weeks after injury, produced by pyramidal tract transection, half of the rats received forelimb motor cortex stimulation of the intact hemisphere. Rats with injury and stimulation had significantly improved forelimb control compared with rats with injury alone and achieved a level of proficiency similar to uninjured rats. To test whether recovery of forelimb function was attributable to ipsilateral control, we selectively inactivated the stimulated motor cortex using the GABA agonist muscimol. The dose of muscimol we used produces strong contralateral but no ipsilateral impairments in naive rats. In rats with injury and stimulation, but not those with injury alone, inactivation caused worsening of forelimb function; the initial deficit was reinstated. These results demonstrate that electrical stimulation can promote recovery of motor function when applied late after injury and that motor control can be exerted from the ipsilateral motor cortex. These results suggest that the uninjured motor cortex could be targeted for brain stimulation in people with large unilateral CST lesions.

Is hemiplegic cerebral palsy equivalent to amblyopia of the corticospinal system?

PubMed

Eyre, Janet A; Smith, Martin; Dabydeen, Lyvia; Clowry, Gavin J; Petacchi, Eliza; Battini, Roberta; Guzzetta, Andrea; Cioni, Giovanni

2007-11-01

Subjects with severe hemiplegic cerebral palsy have increased ipsilateral corticospinal projections from their noninfarcted cortex. We investigated whether their severe impairment might, in part, be caused by activity-dependent, competitive displacement of surviving contralateral corticospinal projections from the affected cortex by more active ipsilateral corticospinal projections from the nonaffected cortex, thereby compounding the impairment. Transcranial magnetic stimulation (TMS) characterized corticospinal tract development from each hemisphere over the first 2 years in 32 healthy children, 14 children with unilateral stroke, and 25 with bilateral lesions. Magnetic resonance imaging and anatomic studies compared corticospinal tract growth in 13 patients with perinatal stroke with 46 healthy subjects. Infants with unilateral lesions initially had responses after TMS of the affected cortex, which became progressively more abnormal, and seven were eventually lost. There was associated hypertrophy of the ipsilateral corticospinal axons projecting from the noninfarcted cortex. Magnetic resonance imaging and anatomic studies demonstrated hypertrophy of the corticospinal tract from the noninfarcted hemisphere. TMS findings soon after the stroke did not predict impairment; subsequent loss of responses and hypertrophy of ipsilateral corticospinal axons from the noninfarcted cortex predicted severe impairment at 2 years. Infants with bilateral lesions maintained responses to TMS from both hemispheres with a normal pattern of development. Rather than representing "reparative plasticity," increased ipsilateral projections from the noninfarcted cortex compound disability by competitively displacing surviving contralateral corticospinal projections from the infarcted cortex. This may provide a pathophysiological explanation for why signs of hemiplegic cerebral palsy appear late and progress over the first 2 years of life.

Interaural Phase and Level Difference Sensitivity in Low-Frequency Neurons in the Lateral Superior Olive

PubMed Central

Tollin, Daniel J.; Yin, Tom C. T.

2006-01-01

The lateral superior olive (LSO) is believed to encode differences in sound level at the two ears, a cue for azimuthal sound location. Most high-frequency-sensitive LSO neurons are binaural, receiving inputs from both ears. An inhibitory input from the contralateral ear, via the medial nucleus of the trapezoid body (MNTB), and excitatory input from the ipsilateral ear enable level differences to be encoded. However, the classical descriptions of low-frequency-sensitive neurons report primarily monaural cells with no contralateral inhibition. Anatomical and physiological evidence, however, shows that low-frequency LSO neurons receive low-frequency inhibitory input from ipsilateral MNTB, which in turn receives excitatory input from the contralateral cochlear nucleus and low-frequency excitatory input from the ipsilateral cochlear nucleus. Therefore, these neurons would be expected to be binaural with contralateral inhibition. Here, we re-examined binaural interaction in low-frequency (less than ~3 kHz) LSO neurons and phase locking in the MNTB. Phase locking to low-frequency tones in MNTB and ipsilaterally driven LSO neurons with frequency sensitivities < 1.2 kHz was enhanced relative to the auditory nerve. Moreover, most low-frequency LSO neurons exhibited contralateral inhibition: ipsilaterally driven responses were suppressed by raising the level of the contralateral stimulus; most neurons were sensitive to interaural time delays in pure tone and noise stimuli such that inhibition was nearly maximal when the stimuli were presented to the ears in-phase. The data demonstrate that low-frequency LSO neurons of cat are not monaural and can exhibit contralateral inhibition like their high-frequency counterparts. PMID:16291937

Physiology of upward transport in the human female genital tract.

PubMed

Zervomanolakis, I; Ott, H W; Hadziomerovic, D; Mattle, V; Seeber, B E; Virgolini, I; Heute, D; Kissler, S; Leyendecker, G; Wildt, L

2007-04-01

The uterus and fallopian tubes represent a functionally united peristaltic pump under the endocrine control of ipsilateral ovary. We have examined this function by using hysterosalpingoscintigraphy (HSS), recording of intrauterine pressure, electrohysterography, and Doppler sonography of the fallopian tubes. An uptake of labeled particles into the uterus was observed during the follicular and luteal phases of the cycle after application into the vagina. Transport into the oviducts, however, could only be demonstrated during the follicular phase. Furthermore, the predominant transport was into the tube ipsilateral to the ovary containing the dominant follicle. The pregnancy rate following spontaneous intercourse or insemination was higher in those women in whom ipsilateral transport could be demonstrated. The amount of material transported to the ipsilateral tube was increased after oxytocin administration, as demonstrated by radionuclide imaging and by Doppler sonography following instillation of ultrasound contrast medium. An increase in the basal tone and amplitude of contractions was observed after oxytocin administration. These results support the idea that the uterus and fallopian tubes act as a peristaltic pump, which increases transport of sperm into the oviduct ipsilateral to the ovary bearing the dominant follicle. Oxytocin appears to play a critical role in this peristaltic pump. A failure of the peristaltic mechanism is possibly responsible for infertility. We propose the term tubal transport disorder (TTD) as a nosological entity. Results from HSS could be a useful adjunct for choosing treatment modalities in patients with patent fallopian tubes suffering from infertility. These patients may be better served with in vitro fertilization (IVF).

Contralateral versus ipsilateral rTMS of temporoparietal cortex for the treatment of chronic unilateral tinnitus: comparative study.

PubMed

Khedr, E M; Abo-Elfetoh, N; Rothwell, J C; El-Atar, A; Sayed, E; Khalifa, H

2010-07-01

Repetitive transcranial magnetic stimulation (rTMS) applied over left temporoparietal cortex has been reported to have a long-term therapeutic effect on tinnitus. We compare the impact of 1 and 25 Hz rTMS delivered either contralateral or ipsilateral to symptoms in 62 patients with unilateral chronic tinnitus. Patients were randomly assigned to one of four treatment groups: with stimulation at 1 or 25 Hz applied either ipsilateral or contralateral to symptoms. Two thousand pulses per session were given daily for 2 weeks. Changes in tinnitus handicap inventory (THI), self-rating scores of loudness, awareness, and annoyance were measured monthly for 10 months. Duration of residual inhibition (RI) and psychiatric morbidity were evaluated monthly for 3 months. There was a significant main effect of time (P < 0.0001) and a significant time x side interaction (P = 0.032) between groups. This was because of the fact that contralateral stimulation had a greater effect on THI than ipsilateral stimulation; it was also superior to left side stimulation (P = 0.027). Ratings of loudness improved more after contralateral rTMS (P = 0.037). Twenty patients had no remaining tinnitus after 3 months; the remainder had a significant increase in RI. Patients with the shortest history of tinnitus tended to respond better to rTMS. There was a significant correlation between changes in THI score and changes in Hamilton anxiety and depression scores. Ten daily treatments of 1 and 25 Hz rTMS contralateral to the side of tinnitus have a greater beneficial effect on symptoms than either ipsilateral or left side stimulation.

Single-unit labeling of medial olivocochlear neurons: the cochlear frequency map for efferent axons.

PubMed

Brown, M Christian

2014-06-01

Medial olivocochlear (MOC) neurons are efferent neurons that project axons from the brain to the cochlea. Their action on outer hair cells reduces the gain of the "cochlear amplifier," which shifts the dynamic range of hearing and reduces the effects of noise masking. The MOC effects in one ear can be elicited by sound in that ipsilateral ear or by sound in the contralateral ear. To study how MOC neurons project onto the cochlea to mediate these effects, single-unit labeling in guinea pigs was used to study the mapping of MOC neurons for neurons responsive to ipsilateral sound vs. those responsive to contralateral sound. MOC neurons were sharply tuned to sound frequency with a well-defined characteristic frequency (CF). However, their labeled termination spans in the organ of Corti ranged from narrow to broad, innervating between 14 and 69 outer hair cells per axon in a "patchy" pattern. For units responsive to ipsilateral sound, the midpoint of innervation was mapped according to CF in a relationship generally similar to, but with more variability than, that of auditory-nerve fibers. Thus, based on CF mappings, most of the MOC terminations miss outer hair cells involved in the cochlear amplifier for their CF, which are located more basally. Compared with ipsilaterally responsive neurons, contralaterally responsive neurons had an apical offset in termination and a larger span of innervation (an average of 10.41% cochlear distance), suggesting that when contralateral sound activates the MOC reflex, the actions are different than those for ipsilateral sound. Copyright © 2014 the American Physiological Society.

Single-unit labeling of medial olivocochlear neurons: the cochlear frequency map for efferent axons

PubMed Central

2014-01-01

Medial olivocochlear (MOC) neurons are efferent neurons that project axons from the brain to the cochlea. Their action on outer hair cells reduces the gain of the “cochlear amplifier,” which shifts the dynamic range of hearing and reduces the effects of noise masking. The MOC effects in one ear can be elicited by sound in that ipsilateral ear or by sound in the contralateral ear. To study how MOC neurons project onto the cochlea to mediate these effects, single-unit labeling in guinea pigs was used to study the mapping of MOC neurons for neurons responsive to ipsilateral sound vs. those responsive to contralateral sound. MOC neurons were sharply tuned to sound frequency with a well-defined characteristic frequency (CF). However, their labeled termination spans in the organ of Corti ranged from narrow to broad, innervating between 14 and 69 outer hair cells per axon in a “patchy” pattern. For units responsive to ipsilateral sound, the midpoint of innervation was mapped according to CF in a relationship generally similar to, but with more variability than, that of auditory-nerve fibers. Thus, based on CF mappings, most of the MOC terminations miss outer hair cells involved in the cochlear amplifier for their CF, which are located more basally. Compared with ipsilaterally responsive neurons, contralaterally responsive neurons had an apical offset in termination and a larger span of innervation (an average of 10.41% cochlear distance), suggesting that when contralateral sound activates the MOC reflex, the actions are different than those for ipsilateral sound. PMID:24598524

Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

PubMed Central

Jankowska, Elzbieta; Hammar, Ingela; Slawinska, Urszula; Maleszak, Katarzyna; Edgley, Stephen A.

2007-01-01

Pathways through which reticulospinal neurons can influence contralateral limb movements were investigated by recording from mo-toneurons innervating hindlimb muscles. Reticulospinal tract fibers were stimulated within the brainstem or in the lateral funiculus of the thoracic spinal cord contralateral to the motoneurons. Effects evoked by ipsilaterally descending reticulospinal tract fibers were eliminated by a spinal hemisection at an upper lumbar level. Stimuli applied in the brainstem evoked EPSPs, IPSPs, or both at latencies of 1.42 ± 0.03 and 1.53 ± 0.04 msec, respectively, from the first components of the descending volleys and with properties indicating a disynaptic linkage, in most contralateral motoneurons: EPSPs in 76% and IPSPs in 26%. EPSPs with characteristics of monosynaptically evoked responses, attributable to direct actions of crossed axon collaterals of reticulospinal fibers, were found in a small proportion of the motoneurons, whether evoked from the brainstem (9%) or from the thoracic cord (12.5%). Commissural neurons, which might mediate the crossed disynaptic actions (i.e., were antidromically activated from contralateral motor nuclei and monosynaptically excited from the ipsilateral reticular formation), were found in Rexed’s lamina VIII in the midlumbar segments (L3–L5). The results reveal that although direct actions of reticulospinal fibers are much more potent on ipsilateral motoneurons, interneuronally mediated actions are as potent contralaterally as ipsilaterally, and midlumbar commissural neurons are likely to contribute to them. They indicate a close coupling between the spinal interneuronal systems used by the reticulospinal neurons to coordinate muscle contractions ipsilaterally and contralaterally. PMID:12629191

Anosognosia for obvious visual field defects in stroke patients.

PubMed

Baier, Bernhard; Geber, Christian; Müller-Forell, Wiebke; Müller, Notger; Dieterich, Marianne; Karnath, Hans-Otto

2015-01-01

Patients with anosognosia for visual field defect (AVFD) fail to recognize consciously their visual field defect. There is still unclarity whether specific neural correlates are associated with AVFD. We studied AVFD in 54 patients with acute stroke and a visual field defect. Nineteen percent of this unselected sample showed AVFD. By using modern voxelwise lesion-behaviour mapping techniques we found an association between AVFD and parts of the lingual gyrus, the cuneus as well as the posterior cingulate and corpus callosum. Damage to these regions appears to induce unawareness of visual field defects and thus may play a significant role for conscious visual perception.

[Woolly hair nevus associated with an ipsilateral linear epidermal nevus].

PubMed

Martín-González, T; del Boz-González, J; Vera-Casaño, A

2007-04-01

We report a 4-year-old boy with two areas of woolly hair in the right parietotemporal region and a linear epidermal nevus in the areas of woolly hair as well as in the ipsilateral hemiface and chin. Evaluation by scanning electron microscopy showed woolly hair with oval transverse section and longitudinal groove. A complete examination ruled out associated anomalies.

The cochlear implant as a tinnitus treatment.

PubMed

Vallés-Varela, Héctor; Royo-López, Juan; Carmen-Sampériz, Luis; Sebastián-Cortés, José M; Alfonso-Collado, Ignacio

2013-01-01

Tinnitus is a symptom of high prevalence in patients with cochlear pathology. We studied the evolution of tinnitus in patients undergoing unilateral cochlear implantation for treatment of profound hearing loss. This was a longitudinal, retrospective study of patients that underwent unilateral cochlear implantation and who had bilateral tinnitus. Tinnitus was assessed quantitatively and qualitatively before surgery and at 6 and 12 months after surgery. We evaluated 20 patients that underwent unilateral cochlear implantation with a Nucleus(®) CI24RE Contour Advance™ electrode device. During the periods in which the device was in operation, improvement or disappearance of tinnitus was evidenced in the ipsilateral ear in 65% of patients, and in the contralateral ear, in 50%. In periods in which the device was disconnected, improvement or disappearance of tinnitus was found in the ipsilateral ear in 50% of patients, and in the ear contralateral to the implant in 45% of the patients. In 10% of the patients, a new tinnitus appeared in the ipsilateral ear. The patients with profound hearing loss and bilateral tinnitus treated with unilateral cochlear implantation improved in a high percentage of cases, in the ipsilateral ear and in the contralateral ear. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Visual motion transforms visual space representations similarly throughout the human visual hierarchy.

PubMed

Harvey, Ben M; Dumoulin, Serge O

2016-02-15

Several studies demonstrate that visual stimulus motion affects neural receptive fields and fMRI response amplitudes. Here we unite results of these two approaches and extend them by examining the effects of visual motion on neural position preferences throughout the hierarchy of human visual field maps. We measured population receptive field (pRF) properties using high-field fMRI (7T), characterizing position preferences simultaneously over large regions of the visual cortex. We measured pRFs properties using sine wave gratings in stationary apertures, moving at various speeds in either the direction of pRF measurement or the orthogonal direction. We find direction- and speed-dependent changes in pRF preferred position and size in all visual field maps examined, including V1, V3A, and the MT+ map TO1. These effects on pRF properties increase up the hierarchy of visual field maps. However, both within and between visual field maps the extent of pRF changes was approximately proportional to pRF size. This suggests that visual motion transforms the representation of visual space similarly throughout the visual hierarchy. Visual motion can also produce an illusory displacement of perceived stimulus position. We demonstrate perceptual displacements using the same stimulus configuration. In contrast to effects on pRF properties, perceptual displacements show only weak effects of motion speed, with far larger speed-independent effects. We describe a model where low-level mechanisms could underlie the observed effects on neural position preferences. We conclude that visual motion induces similar transformations of visuo-spatial representations throughout the visual hierarchy, which may arise through low-level mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

Visualizing second order tensor fields with hyperstreamlines

NASA Technical Reports Server (NTRS)

Delmarcelle, Thierry; Hesselink, Lambertus

1993-01-01

Hyperstreamlines are a generalization to second order tensor fields of the conventional streamlines used in vector field visualization. As opposed to point icons commonly used in visualizing tensor fields, hyperstreamlines form a continuous representation of the complete tensor information along a three-dimensional path. This technique is useful in visulaizing both symmetric and unsymmetric three-dimensional tensor data. Several examples of tensor field visualization in solid materials and fluid flows are provided.

Comparison of Diagnostic Accuracy between Octopus 900 and Goldmann Kinetic Visual Fields

PubMed Central

Rowe, Fiona J.; Rowlands, Alison

2014-01-01

Purpose. To determine diagnostic accuracy of kinetic visual field assessment by Octopus 900 perimetry compared with Goldmann perimetry. Methods. Prospective cross section evaluation of 40 control subjects with full visual fields and 50 patients with known visual field loss. Comparison of test duration and area measurement of isopters for Octopus 3, 5, and 10°/sec stimulus speeds. Comparison of test duration and type of visual field classification for Octopus versus Goldmann perimetry. Results were independently graded for presence/absence of field defect and for type and location of defect. Statistical evaluation comprised of ANOVA and paired t test for evaluation of parametric data with Bonferroni adjustment. Bland Altman and Kappa tests were used for measurement of agreement between data. Results. Octopus 5°/sec perimetry had comparable test duration to Goldmann perimetry. Octopus perimetry reliably detected type and location of visual field loss with visual fields matched to Goldmann results in 88.8% of results (K = 0.775). Conclusions. Kinetic perimetry requires individual tailoring to ensure accuracy. Octopus perimetry was reproducible for presence/absence of visual field defect. Our screening protocol when using Octopus perimetry is 5°/sec for determining boundaries of peripheral isopters and 3°/sec for blind spot mapping with further evaluation of area of field loss for defect depth and size. PMID:24587983

Visual brain plasticity induced by central and peripheral visual field loss.

PubMed

Sanda, Nicolae; Cerliani, Leonardo; Authié, Colas N; Sabbah, Norman; Sahel, José-Alain; Habas, Christophe; Safran, Avinoam B; Thiebaut de Schotten, Michel

2018-06-23

Disorders that specifically affect central and peripheral vision constitute invaluable models to study how the human brain adapts to visual deafferentation. We explored cortical changes after the loss of central or peripheral vision. Cortical thickness (CoTks) and resting-state cortical entropy (rs-CoEn), as a surrogate for neural and synaptic complexity, were extracted in 12 Stargardt macular dystrophy, 12 retinitis pigmentosa (tunnel vision stage), and 14 normally sighted subjects. When compared to controls, both groups with visual loss exhibited decreased CoTks in dorsal area V3d. Peripheral visual field loss also showed a specific CoTks decrease in early visual cortex and ventral area V4, while central visual field loss in dorsal area V3A. Only central visual field loss exhibited increased CoEn in LO-2 area and FG1. Current results revealed biomarkers of brain plasticity within the dorsal and the ventral visual streams following central and peripheral visual field defects.

Form and motion make independent contributions to the response to biological motion in occipitotemporal cortex.

PubMed

Thompson, James C; Baccus, Wendy

2012-01-02

Psychophysical and computational studies have provided evidence that both form and motion cues are used in the perception of biological motion. However, neuroimaging and neurophysiological studies have suggested that the neural processing of actions in temporal cortex might rely on form cues alone. Here we examined the contribution of form and motion to the spatial pattern of response to biological motion in ventral and lateral occipitotemporal cortex, using functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis (MVPA). We found that selectivity to intact versus scrambled biological motion in lateral occipitotemporal cortex was correlated with selectivity for bodies and not for motion. However, this appeared to be due to the fact that subtracting scrambled from intact biological motion removes any contribution of local motion cues. Instead, we found that form and motion made independent contributions to the spatial pattern of responses to biological motion in lateral occipitotemporal regions MT, MST, and the extrastriate body area. The motion contribution was position-dependent, and consistent with the representation of contra- and ipsilateral visual fields in MT and MST. In contrast, only form contributed to the response to biological motion in the fusiform body area, with a bias towards central versus peripheral presentation. These results indicate that the pattern of response to biological motion in ventral and lateral occipitotemporal cortex reflects the linear combination of responses to form and motion. Copyright © 2011 Elsevier Inc. All rights reserved.

The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex

PubMed Central

Bajo, Victoria M; Leach, Nicholas D; Cordery, Patricia M; Nodal, Fernando R; King, Andrew J

2014-01-01

Cholinergic inputs to the auditory cortex can modulate sensory processing and regulate stimulus-specific plasticity according to the behavioural state of the subject. In order to understand how acetylcholine achieves this, it is essential to elucidate the circuitry by which cholinergic inputs influence the cortex. In this study, we described the distribution of cholinergic neurons in the basal forebrain and their inputs to the auditory cortex of the ferret, a species used increasingly in studies of auditory learning and plasticity. Cholinergic neurons in the basal forebrain, visualized by choline acetyltransferase and p75 neurotrophin receptor immunocytochemistry, were distributed through the medial septum, diagonal band of Broca, and nucleus basalis magnocellularis. Epipial tracer deposits and injections of the immunotoxin ME20.4-SAP (monoclonal antibody specific for the p75 neurotrophin receptor conjugated to saporin) in the auditory cortex showed that cholinergic inputs originate almost exclusively in the ipsilateral nucleus basalis. Moreover, tracer injections in the nucleus basalis revealed a pattern of labelled fibres and terminal fields that resembled acetylcholinesterase fibre staining in the auditory cortex, with the heaviest labelling in layers II/III and in the infragranular layers. Labelled fibres with small en-passant varicosities and simple terminal swellings were observed throughout all auditory cortical regions. The widespread distribution of cholinergic inputs from the nucleus basalis to both primary and higher level areas of the auditory cortex suggests that acetylcholine is likely to be involved in modulating many aspects of auditory processing. PMID:24945075

Surgical Treatment for Failure of Repair of Patellar and Quadriceps Tendon Rupture With Ipsilateral Hamstring Tendon Graft.

PubMed

Maffulli, Nicola; Papalia, Rocco; Torre, Guglielmo; Denaro, Vincenzo

2017-03-01

Tears of the patellar and quadriceps tendon are common in the active population, especially in athletes. At present, several techniques for surgical repair and reconstruction are available. When reruptures occur, a reconstruction is mandatory. In the present paper, we describe a surgical technique for patellar and quadriceps tendon reconstruction using ipsilateral hamstring autograft. After routine hamstring tendon harvesting, the tendon ends are prepared using a whip stitch. A transverse tunnel is drilled in the midportion of the patella, the hamstring graft is passed through the patella, and firmly secured to the patellar tunnel openings with sutures. The details of the technique are fully described. Autologous ipsilateral hamstring tendon grafts provide a secure sound means to manage these challenging injuries.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma.

PubMed

Gangeddula, Viswa; Ranchet, Maud; Akinwuntan, Abiodun E; Bollinger, Kathryn; Devos, Hannes

2017-01-01

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma. Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal-Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions. Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups ( p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1-Q3) 3 (2-6.50) vs. 2 (0.50-2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2-6) vs. 1 (0.50-2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls ( p = 0.02). Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

Sunglasses with thick temples and frame constrict temporal visual field.

PubMed

Denion, Eric; Dugué, Audrey Emmanuelle; Augy, Sylvain; Coffin-Pichonnet, Sophie; Mouriaux, Frédéric

2013-12-01

Our aim was to compare the impact of two types of sunglasses on visual field and glare: one ("thick sunglasses") with a thick plastic frame and wide temples and one ("thin sunglasses") with a thin metal frame and thin temples. Using the Goldmann perimeter, visual field surface areas (cm²) were calculated as projections on a 30-cm virtual cupola. A V4 test object was used, from seen to unseen, in 15 healthy volunteers in the primary position of gaze ("base visual field"), then allowing eye motion ("eye motion visual field") without glasses, then with "thin sunglasses," followed by "thick sunglasses." Visual field surface area differences greater than the 14% reproducibility error of the method and having a p < 0.05 were considered significant. A glare test was done using a surgical lighting system pointed at the eye(s) at different incidence angles. No significant "base visual field" or "eye motion visual field" surface area variations were noted when comparing tests done without glasses and with the "thin sunglasses." In contrast, a 22% "eye motion visual field" surface area decrease (p < 0.001) was noted when comparing tests done without glasses and with "thick sunglasses." This decrease was most severe in the temporal quadrant (-33%; p < 0.001). All subjects reported less lateral glare with the "thick sunglasses" than with the "thin sunglasses" (p < 0.001). The better protection from lateral glare offered by "thick sunglasses" is offset by the much poorer ability to use lateral space exploration; this results in a loss of most, if not all, of the additional visual field gained through eye motion.

A randomized controlled trial comparing 2 interventions for visual field loss with standard occupational therapy during inpatient stroke rehabilitation.

PubMed

Mödden, Claudia; Behrens, Marion; Damke, Iris; Eilers, Norbert; Kastrup, Andreas; Hildebrandt, Helmut

2012-06-01

Compensatory and restorative treatments have been developed to improve visual field defects after stroke. However, no controlled trials have compared these interventions with standard occupational therapy (OT). A total of 45 stroke participants with visual field defect admitted for inpatient rehabilitation were randomized to restorative computerized training (RT) using computer-based stimulation of border areas of their visual field defects or to a computer-based compensatory therapy (CT) teaching a visual search strategy. OT, in which different compensation strategies were used to train for activities of daily living, served as standard treatment for the active control group. Each treatment group received 15 single sessions of 30 minutes distributed over 3 weeks. The primary outcome measures were visual field expansion for RT, visual search performance for CT, and reading performance for both treatments. Visual conjunction search, alertness, and the Barthel Index were secondary outcomes. Compared with OT, CT resulted in a better visual search performance, and RT did not result in a larger expansion of the visual field. Intragroup pre-post comparisons demonstrated that CT improved all defined outcome parameters and RT several, whereas OT only improved one. CT improved functional deficits after visual field loss compared with standard OT and may be the intervention of choice during inpatient rehabilitation. A larger trial that includes lesion location in the analysis is recommended.

Interhemispheric integration in visual search

PubMed Central

Shipp, Stewart

2011-01-01

The search task of Luck, Hillyard, Mangun and Gazzaniga (1989) was optimised to test for the presence of a bilateral field advantage in the visual search capabilities of normal subjects. The modified design used geometrically regular arrays of 2, 4 or 8 items restricted to hemifields delineated by the vertical or horizontal meridian; the target, if present, appeared at one of two fixed positions per quadrant at an eccentricity of 11 deg. Group and individual performance data were analysed in terms of the slope of response time against display-size functions (‘RT slope’). Averaging performance across all conditions save display mode (bilateral vs. unilateral) revealed a significant bilateral advantage in the form of a 21% increase in apparent item scanning speed for target detection; in the absence of a target, bilateral displays gave a 5% increase in speed that was not significant. Factor analysis by ANOVA confirmed this main effect of display mode, and also revealed several higher order interactions with display geometry, indicating that the bilateral advantage was masked at certain target positions by a crowding-like effect. In a numerical model of search efficiency (i.e. RT slope), bilateral advantage was parameterised by an interhemispheric ‘transfer factor’ (T) that governs the strength of the ipsilateral representation of distractors, and modifies the level of intrahemispheric competition with the target. The factor T was found to be higher in superior field than inferior field; this result held for the modelled data of each individual subject, as well as the group, representing a uniform tendency for the bilateral advantage to be more prominent in inferior field. In fact statistical analysis and modelling of search efficiency showed that the geometrical display factors (target polar and quadrantic location, and associated crowding effects) were all remarkably consistent across subjects. Greater variability was inferred within a fixed, decisional component of response time, with individual subjects capable of opposite hemifield biases. The results are interpretable by a guided search model of spatial attention – a first, parallel stage guiding selection by a second, serial stage – with the proviso that the first stage is relatively insular within each hemisphere. The bilateral advantage in search efficiency can then be attributed to a relative gain in target weight within the initial parallel stage, owing to a reduction in distractor competition mediated specifically by intrahemispheric circuitry. In the absence of a target there is no effective guidance, and hence no basis for a bilateral advantage to enhance search efficiency; the equivalence of scanning speed for the two display modes (bilateral and unilateral) implies a unitary second-stage process mediated via efficient interhemispheric integration. PMID:21640738

Interhemispheric integration in visual search.

PubMed

Shipp, Stewart

2011-07-01

The search task of Luck, Hillyard, Mangun and Gazzaniga (1989) was optimised to test for the presence of a bilateral field advantage in the visual search capabilities of normal subjects. The modified design used geometrically regular arrays of 2, 4 or 8 items restricted to hemifields delineated by the vertical or horizontal meridian; the target, if present, appeared at one of two fixed positions per quadrant at an eccentricity of 11 deg. Group and individual performance data were analysed in terms of the slope of response time against display-size functions ('RT slope'). Averaging performance across all conditions save display mode (bilateral vs. unilateral) revealed a significant bilateral advantage in the form of a 21% increase in apparent item scanning speed for target detection; in the absence of a target, bilateral displays gave a 5% increase in speed that was not significant. Factor analysis by ANOVA confirmed this main effect of display mode, and also revealed several higher order interactions with display geometry, indicating that the bilateral advantage was masked at certain target positions by a crowding-like effect. In a numerical model of search efficiency (i.e. RT slope), bilateral advantage was parameterised by an interhemispheric 'transfer factor' (T) that governs the strength of the ipsilateral representation of distractors, and modifies the level of intrahemispheric competition with the target. The factor T was found to be higher in superior field than inferior field; this result held for the modelled data of each individual subject, as well as the group, representing a uniform tendency for the bilateral advantage to be more prominent in inferior field. In fact statistical analysis and modelling of search efficiency showed that the geometrical display factors (target polar and quadrantic location, and associated crowding effects) were all remarkably consistent across subjects. Greater variability was inferred within a fixed, decisional component of response time, with individual subjects capable of opposite hemifield biases. The results are interpretable by a guided search model of spatial attention - a first, parallel stage guiding selection by a second, serial stage - with the proviso that the first stage is relatively insular within each hemisphere. The bilateral advantage in search efficiency can then be attributed to a relative gain in target weight within the initial parallel stage, owing to a reduction in distractor competition mediated specifically by intrahemispheric circuitry. In the absence of a target there is no effective guidance, and hence no basis for a bilateral advantage to enhance search efficiency; the equivalence of scanning speed for the two display modes (bilateral and unilateral) implies a unitary second-stage process mediated via efficient interhemispheric integration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Visual Half-Field Experiments Are a Good Measure of Cerebral Language Dominance if Used Properly: Evidence from fMRI

ERIC Educational Resources Information Center

Hunter, Zoe R.; Brysbaert, Marc

2008-01-01

Traditional neuropsychology employs visual half-field (VHF) experiments to assess cerebral language dominance. This approach is based on the assumption that left cerebral dominance for language leads to faster and more accurate recognition of words in the right visual half-field (RVF) than in the left visual half-field (LVF) during tachistoscopic…

Cortical lamina-dependent blood volume changes in human brain at 7 T.

PubMed

Huber, Laurentius; Goense, Jozien; Kennerley, Aneurin J; Trampel, Robert; Guidi, Maria; Reimer, Enrico; Ivanov, Dimo; Neef, Nicole; Gauthier, Claudine J; Turner, Robert; Möller, Harald E

2015-02-15

Cortical layer-dependent high (sub-millimeter) resolution functional magnetic resonance imaging (fMRI) in human or animal brain can be used to address questions regarding the functioning of cortical circuits, such as the effect of different afferent and efferent connectivities on activity in specific cortical layers. The sensitivity of gradient echo (GE) blood oxygenation level-dependent (BOLD) responses to large draining veins reduces its local specificity and can render the interpretation of the underlying laminar neural activity impossible. The application of the more spatially specific cerebral blood volume (CBV)-based fMRI in humans has been hindered by the low sensitivity of the noninvasive modalities available. Here, a vascular space occupancy (VASO) variant, adapted for use at high field, is further optimized to capture layer-dependent activity changes in human motor cortex at sub-millimeter resolution. Acquired activation maps and cortical profiles show that the VASO signal peaks in gray matter at 0.8-1.6mm depth, and deeper compared to the superficial and vein-dominated GE-BOLD responses. Validation of the VASO signal change versus well-established iron-oxide contrast agent based fMRI methods in animals showed the same cortical profiles of CBV change, after normalization for lamina-dependent baseline CBV. In order to evaluate its potential of revealing small lamina-dependent signal differences due to modulations of the input-output characteristics, layer-dependent VASO responses were investigated in the ipsilateral hemisphere during unilateral finger tapping. Positive activation in ipsilateral primary motor cortex and negative activation in ipsilateral primary sensory cortex were observed. This feature is only visible in high-resolution fMRI where opposing sides of a sulcus can be investigated independently because of a lack of partial volume effects. Based on the results presented here, we conclude that VASO offers good reproducibility, high sensitivity and lower sensitivity than GE-BOLD to changes in larger vessels, making it a valuable tool for layer-dependent fMRI studies in humans. Copyright © 2014 Elsevier Inc. All rights reserved.

SU-G-BRC-13: Model Based Classification for Optimal Position Selection for Left-Sided Breast Radiotherapy: Free Breathing, DIBH, Or Prone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, H; Liu, T; Xu, X

Purpose: There are clinical decision challenges to select optimal treatment positions for left-sided breast cancer patients—supine free breathing (FB), supine Deep Inspiration Breath Hold (DIBH) and prone free breathing (prone). Physicians often make the decision based on experiences and trials, which might not always result optimal OAR doses. We herein propose a mathematical model to predict the lowest OAR doses among these three positions, providing a quantitative tool for corresponding clinical decision. Methods: Patients were scanned in FB, DIBH, and prone positions under an IRB approved protocol. Tangential beam plans were generated for each position, and OAR doses were calculated.more » The position with least OAR doses is defined as the optimal position. The following features were extracted from each scan to build the model: heart, ipsilateral lung, breast volume, in-field heart, ipsilateral lung volume, distance between heart and target, laterality of heart, and dose to heart and ipsilateral lung. Principal Components Analysis (PCA) was applied to remove the co-linearity of the input data and also to lower the data dimensionality. Feature selection, another method to reduce dimensionality, was applied as a comparison. Support Vector Machine (SVM) was then used for classification. Thirtyseven patient data were acquired; up to now, five patient plans were available. K-fold cross validation was used to validate the accuracy of the classifier model with small training size. Results: The classification results and K-fold cross validation demonstrated the model is capable of predicting the optimal position for patients. The accuracy of K-fold cross validations has reached 80%. Compared to PCA, feature selection allows causal features of dose to be determined. This provides more clinical insights. Conclusion: The proposed classification system appeared to be feasible. We are generating plans for the rest of the 37 patient images, and more statistically significant results are to be presented.« less

Comparison of Three Methods of Assessing Muscle Strength and Imbalance Ratios of the Knee

PubMed Central

Moss, Crayton L.; Wright, P. Thomas

1993-01-01

Three strength measurement methods for determining muscle strength and imbalance ratios of the knee were compared in 41 (23 female, 18 male) NCAA Division I track and field athletes. Peak quadriceps extensions and hamstring flexions were measured isotonically, isometrically, and isokinetically. Isokinetic measurements were performed on a Cybex II at 60°/s. Isometric extension and flexion measurements were performed using the Nicholas Manual Muscle Tester (Lafayette Instruments; Lafayette, Ind). Isotonic measurements were done on both Universal and Nautilus apparatuses. Testing order was randomized to avoid a treatment order effect. A repeated measures ANOVA and a post hoc Tukey test were used to compare the three methods of assessing strength and imbalance ratios of the knee. Absolute strength values were significantly different according to gender and mode of testing. Bilateral strength imbalance ratios for knee flexion were significantly lower for the Nautilus leg curl machine. Ipsilateral strength imbalance ratios were significantly greater for the Cybex II. Our results indicated that absolute strength values cannot be interchanged between testing modes. Except for Cybex II (ipsilateral) and Nautilus (bilateral knee flexion), strength imbalance ratios could be interchanged. ImagesFig 1.Fig 2.Fig 3.Fig 4.Fig 5.Fig 6.Fig 7.INGING PMID:16558207

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lakshminarayan, Raghuram; Scott, Paul M.; Robinson, Graham J.

Carotid stump syndrome is one of the recognised causes of recurrent ipsilateral cerebrovascular events after occlusion of the internal carotid artery. It is believed that microemboli arising from the stump of the occluded internal carotid artery or the ipsilateral external carotid artery can pass into the middle cerebral artery circulation as a result of patent external carotid-internal carotid anastomotic channels. Different pathophysiologic causes of this syndrome and endovascular options for treatment are discussed.

Experimental study of hemodynamics in the Circle of Willis.

PubMed

Zhu, Guangyu; Yuan, Qi; Yang, Jian; Yeo, Joon

2015-01-01

The Circle of Willis (CoW) is an important collateral pathway of the cerebral blood flow. An experimental study of the cerebral blood flow (CBF) distribution in different anatomical variations may help to a better understanding of the collateral mechanism of the CoW. An in-vitro test rig was developed to simulate the physiological cerebral blood flow in the CoW. Ten anatomical variations were considered in this study, include a set of different degrees of stenosis in L-ICA and L-ICA occlusion coexist with common anatomical variations. Volume flow rates of efferent arteries and pressure signals at the end of communicating arteries of each case were recorded. Physiological pressure waveforms were applied as inlet boundary condition. In the development of L-ICA stenosis, the total CBF decreases with the increase of stenosis degree. The blood supply of ipsilateral middle cerebral artery (MCA) was affected most by the stenosis of L-ICA. Anterior communicating artery (ACoA) and ipsilateral posterior communicating artery (PCoA) function as important collateral pathways of cerebral collateral circulation when unilateral stenosis occurred. The blood supply of anterior cerebral circulation was compensated by the posterior cerebral circulation through ipsilateral PCoA when L-ICA stenosis degree is greater than 40% and the affected side was compensated immediately by the unaffected side through ACoA. Blood flow of the anterior circulation and the total CBF reached the minimum among all cases studied when L-ICA occlusion coexist with the absence of PCoA. The results demonstrated the flow distribution patterns of the CoW under anatomical variations and clarified the collateral mechanism of the CoW. The flow ACoA is the most sensitive indexes to the morphology change of ipsilateral ICA. The relative independence of the circulation in anterior and posterior sections of the CoW is not broken and the function of ipsilateral PCoA is not activated until a severe stenosis of unilateral ICA occurs. PCoA is the most important collateral pathway of the collateral circulation and the missing of PCoA has the highest risk of stroke when the ipsilateral ICA has severe stenosis. These findings may provide the basis for future therapeutic and diagnosis applications.

Appraising the plasticity of the circle of Willis: a model of hemodynamic modulation in cerebral arteriovenous malformations.

PubMed

Chuang, Yu-Ming; Guo, Wanyuo; Lin, Ching-Po

2010-01-01

Cerebral arteriovenous malformations (AVMs) harbor a network of abnormal vasculatures, namely the nidus between arterial and venous components. The pressure gradient between these two components results in abnormal high-velocity arteriovenous shunts flowing through the nidus and alternate intracranial hemodynamics. This study hypothesizes that the flow patterns of the circle of Willis (CoW) are modulated by the alternation of intracranial hemodynamics occurring in cerebral AVMs. The flow patterns of the CoW before and after AVMs had been corrected and the arteriovenous shunts closed by radiosurgery were assessed to validate the hypothesis. Fifty patients (32 men and 18 women; mean age 35.8 +/- 4.2, range 23-52 years) with cerebral AVMs previously treated by radiosurgery were retrospectively investigated. This investigation used magnetic resonance angiography, performed prior to and after AVM surgery, to assess the CoW flow patterns. The CoW flow patterns in nearly half of the subjects (20/50, 40%) altered after the AVMs had been corrected. The alterations included: (1) decreased size or ceased flow patterns in the CoW vascular segment: ipsilateral A1 (n = 1) of the anterior cerebral artery (ACA), ipsilateral posterior communicating artery (PCoA) segment (n = 7), contralateral PCoA collateral (n = 4), bilateral PCoA (n = 2); (2) increased size or opening of the previous 'hypoplastic' segment of CoW: ipsilateral A1 of ACA (n = 1), contralateral PCoA (n = 2), bilateral PCoA (n = 1), and (3) biphasic alteration of the CoW: ceased ipsilateral PCoA segment and opening ipsilateral A1 of the ACA (n = 1), ceased ipsilateral PCoA and opening contralateral P1 of the posterior cerebral artery (n = 1). The plasticity of the flow patterns in the CoW are modulated by intracranial hemodynamics as shown by the AVM model. The calibers of CoW arterial segments are not a static feature. Willisian collateralization with recruitment of the CoW segment may cease, or hypoplastic segments may reopen after closing arteriovenous shunts of the AVM. (c) 2010 S. Karger AG, Basel.

Assessment of Ipsilateral Efferent Effects in Human via ECochG

PubMed Central

Verschooten, Eric; Strickland, Elizabeth A.; Verhaert, Nicolas; Joris, Philip X.

2017-01-01

Development of electrophysiological means to assess the medial olivocochlear (MOC) system in humans is important to further our understanding of the function of that system and for the refinement and validation of psychoacoustical and otoacoustic emission methods which are thought to probe the MOC. Based on measurements in anesthetized animals it has been hypothesized that the MOC-reflex (MOCR) can enhance the response to signals in noise, and several lines of evidence support such a role in humans. A difficulty in these studies is the isolation of efferent effects. Efferent activation can be triggered by acoustic stimulation of the contralateral or ipsilateral ear, but ipsilateral stimulation is thought to be more effective. However, ipsilateral stimulation complicates interpretation of effects since these sounds can affect the perception of other ipsilateral sounds by mechanisms not involving olivocochlear efferents. We assessed the ipsilaterally evoked MOCR in human using a transtympanic procedure to record mass-potentials from the cochlear promontory or the niche of the round window. Averaged compound action potential (CAP) responses to masked probe tones of 4 kHz with and without a precursor (designed to activate the MOCR but not the stapedius reflex) were extracted with a polarity alternating paradigm. The masker was either a simultaneous narrow band noise masker or a short (20-ms) tonal ON- or OFF-frequency forward masker. The subjects were screened for normal hearing (audiogram, tympanogram, threshold stapedius reflex) and psychoacoustically tested for the presence of a precursor effect. We observed a clear reduction of CAP amplitude by the precursor, for different masking conditions. Even without an MOCR, this is expected because the precursor will affect the response to subsequent stimuli via neural adaptation. To determine whether the precursor also activated the efferent system, we measured the CAP over a range of masker levels, with or without precursor, and for different types of masker. The results show CAP reduction consistent with the type of gain reduction caused by the MOCR. These results generally support psychoacoustical paradigms designed to probe the efferent system as indeed activating the MOCR system, but not all observations are consistent with this mechanism. PMID:28642679

Masking overshoot: Effects of ipsilateral, bilateral and contralateral priming

NASA Astrophysics Data System (ADS)

Connington, Maureen Catherine

This study was concerned with masking overshoot, the elevation of the threshold of a brief signal when it is presented at the onset of a masking noise rather than at its temporal center. More specifically, it was concerned with the release from overshoot (i.e., threshold improvement) produced by priming stimuli, presented ipsilaterally, bilaterally and contralaterally at primer- masker gaps of 20, 40 and 80 msec. The more general purpose of the study was to assess the contributions of peripheral and central factors to the overshoot and overshoot-release phenomena. The primers and masking stimuli consisted of white noise bursts of 200 and 400 msec duration, respectively. The probe signal was a 20 msec 4kHz tone. The tone and masker were always presented in one ear. There were, however, 3 modes of primer presentation: ipsilateral, bilateral (identical waveforms to both ears) and contralateral. Three primer-masker gaps of 20, 40 and 80 msec were used. Five normally hearing adults were tested at primer and masker levels of 80 dB HL. Four of the five subjects exhibited significant masking overshoot, when tested without priming. Ipsilateral priming with 20 and 40 msec gaps produced significant masking release from overshoot. Threshold became poorer, however with increasing gap duration and with increasing distance of the perceived primer from the test ear (i.e. ipsilateral priming produced better thresholds than did bilateral priming and bilateral priming produced better thresholds than contralateral priming). There was significant masking enhancement (i.e. threshold was significantly poorer than in the unprimed probe at onset condition) with the contralateral 80 msec primer. The fact that ipsilateral and bilateral primers performed differently does not support the theory that masking overshoot and its release are solely the results of peripheral adaptation. In fact, the group results support the conclusion that masking overshoot is influenced by central factors. However, there were marked inter-subject differences. It seems possible that masking overshoot and its release are influenced by both peripheral adaptation effects and central processes and that the balance between the two is subject-dependent.

Effectiveness of Breast MRI and (18)F-FDG PET/CT for the Preoperative Staging of Invasive Lobular Carcinoma versus Ductal Carcinoma.

PubMed

Jung, Na Young; Kim, Sung Hoon; Kim, Sung Hun; Seo, Ye Young; Oh, Jin Kyoung; Choi, Hyun Su; You, Won Jong

2015-03-01

We evaluated the utility of magnetic resonance imaging (MRI) and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for the preoperative staging of invasive lobular carcinoma (ILC) of the breast and compared the results with those of invasive ductal carcinoma (IDC). The study included pathologically proven 32 ILCs and 73 IDCs. We compared clinical and histopathological characteristics and the diagnostic performances of MRI and (18)F-FDG PET/CT for the primary mass, additional ipsilateral and/or contralateral lesion(s), and axillary lymph node metastasis between the ILC and IDC groups. Primary ILCs were greater in size, but demonstrated lower maximum standardized uptake values than IDCs. All primary masses were detected on MRI. The detection rate for ILCs (75.0%) was lower than that for IDCs (83.6%) on (18)F-FDG PET/CT, but the difference was not significant. For additional ipsilateral lesion(s), the sensitivities and specificities of MRI were 87.5% and 58.3% for ILC and 100.0% and 66.7% for IDC, respectively; whereas the sensitivities and specificities of (18)F-FDG PET/CT were 0% and 91.7% for ILC and 37.5% and 94.7% for IDC, respectively. The sensitivity of (18)F-FDG PET/CT for ipsilateral lesion(s) was significantly lower in the ILC group than the IDC group. The sensitivity for ipsilateral lesion(s) was significantly higher with MRI; however, specificity was higher with (18)F-FDG PET/CT in both tumor groups. There was no significant difference in the diagnostic performance for additional contralateral lesion(s) or axillary lymph node metastasis on MRI or (18)F-FDG PET/CT for ILC versus IDC. The MRI and (18)F-FDG PET/CT detection rates for the primary cancer do not differ between the ILC and IDC groups. Although (18)F-FDG PET/CT demonstrates lower sensitivity for primary and additional ipsilateral lesions, it shows higher specificity for additional ipsilateral lesions, and could play a complementary role in the staging of ILC as well as IDC.

Mechanisms Underlying Development of Visual Maps and Receptive Fields

PubMed Central

Huberman, Andrew D.; Feller, Marla B.; Chapman, Barbara

2008-01-01

Patterns of synaptic connections in the visual system are remarkably precise. These connections dictate the receptive field properties of individual visual neurons and ultimately determine the quality of visual perception. Spontaneous neural activity is necessary for the development of various receptive field properties and visual feature maps. In recent years, attention has shifted to understanding the mechanisms by which spontaneous activity in the developing retina, lateral geniculate nucleus, and visual cortex instruct the axonal and dendritic refinements that give rise to orderly connections in the visual system. Axon guidance cues and a growing list of other molecules, including immune system factors, have also recently been implicated in visual circuit wiring. A major goal now is to determine how these molecules cooperate with spontaneous and visually evoked activity to give rise to the circuits underlying precise receptive field tuning and orderly visual maps. PMID:18558864

Visual field progression in glaucoma: total versus pattern deviation analyses.

PubMed

Artes, Paul H; Nicolela, Marcelo T; LeBlanc, Raymond P; Chauhan, Balwantray C

2005-12-01

To compare visual field progression with total and pattern deviation analyses in a prospective longitudinal study of patients with glaucoma and healthy control subjects. A group of 101 patients with glaucoma (168 eyes) with early to moderately advanced visual field loss at baseline (average mean deviation [MD], -3.9 dB) and no clinical evidence of media opacity were selected from a prospective longitudinal study on visual field progression in glaucoma. Patients were examined with static automated perimetry at 6-month intervals for a median follow-up of 9 years. At each test location, change was established with event and trend analyses of total and pattern deviation. The event analyses compared each follow-up test to a baseline obtained from averaging the first two tests, and visual field progression was defined as deterioration beyond the 5th percentile of test-retest variability at three test locations, observed on three consecutive tests. The trend analyses were based on point-wise linear regression, and visual field progression was defined as statistically significant deterioration (P < 5%) worse than -1 dB/year at three locations, confirmed by independently omitting the last and the penultimate observation. The incidence and the time-to-progression were compared between total and pattern deviation analyses. To estimate the specificity of the progression analyses, identical criteria were applied to visual fields obtained in 102 healthy control subjects, and the rate of visual field improvement was established in the patients with glaucoma and the healthy control subjects. With both event and trend methods, pattern deviation analyses classified approximately 15% fewer eyes as having progressed than did the total deviation analyses. In eyes classified as progressing by both the total and pattern deviation methods, total deviation analyses tended to detect progression earlier than the pattern deviation analyses. A comparison of the changes observed in MD and the visual fields' general height (estimated by the 85th percentile of the total deviation values) confirmed that change in the glaucomatous eyes almost always comprised a diffuse component. Pattern deviation analyses of progression may therefore underestimate the true amount of glaucomatous visual field progression. Pattern deviation analyses of visual field progression may underestimate visual field progression in glaucoma, particularly when there is no clinical evidence of increasing media opacity. Clinicians should have access to both total and pattern deviation analyses to make informed decisions on visual field progression in glaucoma.

Action video game players and deaf observers have larger Goldmann visual fields.

PubMed

Buckley, David; Codina, Charlotte; Bhardwaj, Palvi; Pascalis, Olivier

2010-03-05

We used Goldmann kinetic perimetry to compare how training and congenital auditory deprivation may affect the size of the visual field. We measured the ability of action video game players and deaf observers to detect small moving lights at various locations in the central (around 30 degrees from fixation) and peripheral (around 60 degrees ) visual fields. Experiment 1 found that 10 habitual video game players showed significantly larger central and peripheral field areas than 10 controls. In Experiment 2 we found that 13 congenitally deaf observers had significantly larger visual fields than 13 hearing controls for both the peripheral and central fields. Here the greatest differences were found in the lower parts of the fields. Comparison of the two groups showed that whereas VGP players have a more uniform increase in field size in both central and peripheral fields deaf observers show non-uniform increases with greatest increases in lower parts of the visual field.

The mapping of the visual field onto the dorso-lateral tectum of the pigeon (Columba livia) and its relations with retinal specializations.

PubMed

Letelier, Juan-Carlos; Marin, Gonzalo; Sentis, Elisa; Tenreiro, Andrea; Fredes, Felipe; Mpodozis, Jorge

2004-01-30

Most of the physiological studies of the pigeon retino-tectal visual pathway have investigated the accessible tectum, a small dorso-lateral tectal section that can be easily accessed by a simple craniotomy. However, at present we lack a detailed study of the topographical arrangement between the visual field, the retina and the accessible tectum. In particular, it is not known which section of the visual field is mapped onto the accessible tectum, and which of the specialized retinal areas mediates this projection. Here we determined, using local field potential (LFP) recordings and reverse retinoscopy, the shape, size and position in the visual space of the portion of the visual field mapped onto the accessible tectum (called here the accessible visual field, or AVF). Using this data and the mapping of Nalbach et al. [Vis. Res. 30 (4) (1990) 529], the retinal area corresponding to the AVF was determined. Such retinal area was also directly delimited by means of retrograde transport of DiI. The results indicate that the AVF is a triangular perifoveal zone encompassing only 15% of total visual field. The retinal region corresponding to the AVF has the shape of an elongated triangle that runs parallel to the visual equator and contains the fovea, the tip of the pecten, a perifoveal region of the yellow field and a small crescent of the red field. In agreement with this anatomical heterogeneity, visual evoked potentials measured in different parts of the accessible tectum present steep variations in shape and size. These results are helpful to better design and interpret anatomical and physiological experiments involving the pigeon's visual system.

Medical review licensing outcomes in drivers with visual field loss in Victoria, Australia

PubMed Central

Muir, Carlyn; Charlton, Judith L; Odell, Morris; Keeffe, Jill; Wood, Joanne; Bohensky, Megan; Fildes, Brian; Oxley, Jennifer; Bentley, Sharon; Rizzo, Matthew

2017-01-01

Background Good vision is essential for safe driving and studies have associated visual impairment with an increased crash risk. Currently, there is little information about the medical review of drivers with visual field loss. This study examines the prevalence of visual field loss among drivers referred for medical review in one Australian jurisdiction and investigates factors associated with licence outcome in this group. Methods A random sample of 10,000 (31.25 per cent) medical review cases was extracted for analysis from the Victorian licensing authority. Files were screened for the presence of six visual field-related medical conditions. Data were captured on a range of variables, including referral source, age, gender, health status, crash history and licence outcome. Prevalence analyses were univariate and descriptive. Logistic regression was used to assess factors associated with licence outcomes in the visual field loss group. Results Approximately 1.9 per cent of the 10,000 medical review cases screened had a visual field loss condition identified (n=194). Among the visual field loss group, 57.2 per cent were permitted to continue driving (conditional/unconditional licence). Primary referral sources were the police, self-referrals and general medical practitioners. Key factors associated with licence test outcomes were visual field condition, age group, crash involvement and referral to the Driver Licensing Authority’s Medical Advisors. Those who were younger had a crash involvement triggering referral and those who were referred to the Medical Advisors were more likely to have a positive licensing outcome. Conclusion The evidence base for making licensing decisions is complicated by the variable causes, patterns, progressions and measuring technologies for visual field loss. This study highlighted that the involvement of an expert medical advisory service in Victoria resulted in an increased likelihood that drivers with visual field loss will be allowed to continue driving. Further research is warranted to explore issues relating to severity of field loss and the capacity for compensation. PMID:27530283

ERP effects of spatial attention and display search with unilateral and bilateral stimulus displays.

PubMed

Lange, J J; Wijers, A A; Mulder, L J; Mulder, G

1999-07-01

Two experiments were performed in which the effects of selective spatial attention on the ERPs elicited by unilateral and bilateral stimulus arrays were compared. In Experiment 1, subjects received a series of grating patterns. In the unilateral condition these gratings were presented one at a time, randomly to the right or left of fixation. In the bilateral condition, gratings were presented in pairs, one to each side of fixation. In the unilateral condition standard ERP effects of visual spatial attention were observed. However, in the bilateral condition we failed to observe an attention related posterior contralateral positivity (overlapping the P1 and N1 components, latency interval about 100-250 ms), as reported in several previous studies. In Experiment 2, we investigated whether attention related ERP lateralizations are affected by the task requirement to search among multiple objects in the visual field. We employed a task paradigm identical to that used by Luck et al. (Luck, S.J., Heinze, H.J., Mangun, G.R., Hillyard, S.A., 1990. Visual event-related potentials index focused attention within bilateral stimulus arrays. II. Functional dissociation of P1 and N1 components. Electroencephalogr. Clin. Neurophysiol. 75, 528-542). Four letters were presented to a visual hemifield, simultaneously to both the attended and unattended hemifields in the bilateral conditions, and to one hemifield only in the unilateral conditions. In a focused attention condition, subjects searched for a target letter at a fixed position, whereas they searched for the target letter among all four letters in the divided attention condition (as in the experiment of Luck et al., 1990). In the bilateral focused attention condition, only the contralateral P1 was enhanced. In the bilateral divided attention condition a prolonged posterior positivity was observed over the hemisphere contralateral to the attended hemifield, comparable to the results of Luck et al. (1990). A comparison of the ERPs elicited in the focused and divided attention conditions revealed a prolonged 'search related negativity'. We discuss possible interactions between this negativity and attention related lateralizations. The display search negativity consisted of two phases, one phase comprised a midline occipital negativity, developing first over the ipsilateral scalp, while the second phase involved two symmetrical occipitotemporal negativities, strongly resembling the N1 in their topography. The display search effect could be modelled with a dipole in a medial occipital (possibly striate) region and two symmetrical dipoles in occipitotemporal brain areas. We hypothesize that this effect reflects a process of rechecking the decaying information of iconic memory in the occipitotemporal object recognition pathway.

Visual field impairment captures disease burden in multiple sclerosis.

PubMed

Ortiz-Perez, Santiago; Andorra, Magí; Sanchez-Dalmau, Bernardo; Torres-Torres, Rubén; Calbet, David; Lampert, Erika J; Alba-Arbalat, Salut; Guerrero-Zamora, Ana M; Zubizarreta, Irati; Sola-Valls, Nuria; Llufriu, Sara; Sepúlveda, María; Saiz, Albert; Villoslada, Pablo; Martinez-Lapiscina, Elena H

2016-04-01

Monitoring disease burden is an unmeet need in multiple sclerosis (MS). Identifying patients at high risk of disability progression will be useful for improving clinical-therapeutic decisions in clinical routine. To evaluate the role of visual field testing in non-optic neuritis eyes (non-ON eyes) as a biomarker of disability progression in MS. In 109 patients of the MS-VisualPath cohort, we evaluated the association between visual field abnormalities and global and cognitive disability markers and brain and retinal imaging markers of neuroaxonal injury using linear regression models adjusted for sex, age, disease duration and use of disease-modifying therapies. We evaluated the risk of disability progression associated to have baseline impaired visual field after 3 years of follow-up. Sixty-two percent of patients showed visual field defects in non-ON eyes. Visual field mean deviation was statistically associated with global disability; brain (normalized brain parenchymal, gray matter volume and lesion load) and retinal (peripapillary retinal nerve fiber layer thickness and macular ganglion cell complex thickness) markers of neuroaxonal damage. Patients with impaired visual field had statistically significative greater disability, lower normalized brain parenchymal volume and higher lesion volume than patients with normal visual field testing. MS patients with baseline impaired VF tripled the risk of disability progression during follow-up [OR = 3.35; 95 % CI (1.10-10.19); p = 0.033]. The association of visual field impairment with greater disability and neuroaxonal injury and higher risk of disability progression suggest that VF could be used to monitor MS disease burden.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma

PubMed Central

Gangeddula, Viswa; Ranchet, Maud; Akinwuntan, Abiodun E.; Bollinger, Kathryn; Devos, Hannes

2017-01-01

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma. Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions. Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups (p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3) 3 (2–6.50) vs. controls: 2 (0.50–2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6) vs. controls: 1 (0.50–2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02). Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma. PMID:28912712

Ipsilateral Irradiation for Oral and Oropharyngeal Carcinoma Treated With Primary Surgery and Postoperative Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vergeer, Marije R., E-mail: mr.vergeer@vumc.n; Doornaert, Patricia; Jonkman, Anja

Purpose: The purpose was to evaluate the contralateral nodal control (CLNC) in postoperative patients with oral and oropharyngeal cancer treated with ipsilateral irradiation of the neck and primary site. Late radiation-induced morbidity was also evaluated. Methods and Materials: The study included 123 patients with well-lateralized squamous cell carcinomas treated with surgery and unilateral postoperative irradiation. Most patients had tumors of the gingiva (41%) or buccal mucosa (21%). The majority of patients underwent surgery of the ipsilateral neck (n = 102 [83%]). The N classification was N0 in 73 cases (59%), N1 or N2a in 23 (19%), and N2b in 27more » cases (22%). Results: Contralateral metastases developed in 7 patients (6%). The 5-year actuarial CLNC was 92%. The number of lymph node metastases was the only significant prognostic factor with regard to CLNC. The 5-year CLNC was 99% in N0 cases, 88% in N1 or N2a cases, and 73% in N2b cases (p = 0.008). Borderline significance (p = 0.06) was found for extranodal spread. Successful salvage could be performed in 71% of patients with contralateral metastases. The prevalence of Grade 2 or higher xerostomia was 2.6% at 5 years. Conclusions: Selected patients with oral or oropharyngeal carcinoma treated with primary surgery and postoperative ipsilateral radiotherapy have a very high CLNC with a high probability of successful salvage in case of contralateral metastases. However, bilateral irradiation should be applied in case of multiple lymph node metastases in the ipsilateral neck, particularly in the presence of extranodal spread. The incidence of radiation-induced morbidity is considerably lower as observed after bilateral irradiation.« less

Predictors of pneumothorax following endoscopic valve therapy in patients with severe emphysema.

PubMed

Gompelmann, Daniela; Lim, Hyun-Ju; Eberhardt, Ralf; Gerovasili, Vasiliki; Herth, Felix Jf; Heussel, Claus Peter; Eichinger, Monika

2016-01-01

Endoscopic valve implantation is an effective treatment for patients with advanced emphysema. Despite the minimally invasive procedure, valve placement is associated with risks, the most common of which is pneumothorax. This study was designed to identify predictors of pneumothorax following endoscopic valve implantation. Preinterventional clinical measures (vital capacity, forced expiratory volume in 1 second, residual volume, total lung capacity, 6-minute walk test), qualitative computed tomography (CT) parameters (fissure integrity, blebs/bulla, subpleural nodules, pleural adhesions, partial atelectasis, fibrotic bands, emphysema type) and quantitative CT parameters (volume and low attenuation volume of the target lobe and the ipsilateral untreated lobe, target air trapping, ipsilateral lobe volume/hemithorax volume, collapsibility of the target lobe and the ipsilateral untreated lobe) were retrospectively evaluated in patients who underwent endoscopic valve placement (n=129). Regression analysis was performed to compare those who developed pneumothorax following valve therapy (n=46) with those who developed target lobe volume reduction without pneumothorax (n=83). Low attenuation volume% of ipsilateral untreated lobe (odds ratio [OR] =1.08, P=0.001), ipsilateral untreated lobe volume/hemithorax volume (OR =0.93, P=0.017), emphysema type (OR =0.26, P=0.018), pleural adhesions (OR =0.33, P=0.012) and residual volume (OR =1.58, P=0.012) were found to be significant predictors of pneumothorax. Fissure integrity (OR =1.16, P=0.075) and 6-minute walk test (OR =1.05, P=0.077) were also indicative of pneumothorax. The model including the aforementioned parameters predicted whether a patient would experience a pneumothorax 84% of the time (area under the curve =0.84). Clinical and CT parameters provide a promising tool to effectively identify patients at high risk of pneumothorax following endoscopic valve therapy.

Predictors of pneumothorax following endoscopic valve therapy in patients with severe emphysema

PubMed Central

Gompelmann, Daniela; Lim, Hyun-ju; Eberhardt, Ralf; Gerovasili, Vasiliki; Herth, Felix JF; Heussel, Claus Peter; Eichinger, Monika

2016-01-01

Background Endoscopic valve implantation is an effective treatment for patients with advanced emphysema. Despite the minimally invasive procedure, valve placement is associated with risks, the most common of which is pneumothorax. This study was designed to identify predictors of pneumothorax following endoscopic valve implantation. Methods Preinterventional clinical measures (vital capacity, forced expiratory volume in 1 second, residual volume, total lung capacity, 6-minute walk test), qualitative computed tomography (CT) parameters (fissure integrity, blebs/bulla, subpleural nodules, pleural adhesions, partial atelectasis, fibrotic bands, emphysema type) and quantitative CT parameters (volume and low attenuation volume of the target lobe and the ipsilateral untreated lobe, target air trapping, ipsilateral lobe volume/hemithorax volume, collapsibility of the target lobe and the ipsilateral untreated lobe) were retrospectively evaluated in patients who underwent endoscopic valve placement (n=129). Regression analysis was performed to compare those who developed pneumothorax following valve therapy (n=46) with those who developed target lobe volume reduction without pneumothorax (n=83). Finding Low attenuation volume% of ipsilateral untreated lobe (odds ratio [OR] =1.08, P=0.001), ipsilateral untreated lobe volume/hemithorax volume (OR =0.93, P=0.017), emphysema type (OR =0.26, P=0.018), pleural adhesions (OR =0.33, P=0.012) and residual volume (OR =1.58, P=0.012) were found to be significant predictors of pneumothorax. Fissure integrity (OR =1.16, P=0.075) and 6-minute walk test (OR =1.05, P=0.077) were also indicative of pneumothorax. The model including the aforementioned parameters predicted whether a patient would experience a pneumothorax 84% of the time (area under the curve =0.84). Interpretation Clinical and CT parameters provide a promising tool to effectively identify patients at high risk of pneumothorax following endoscopic valve therapy. PMID:27536088

Head repositioning accuracy in patients with whiplash-associated disorders.

PubMed

Feipel, Veronique; Salvia, Patrick; Klein, Helene; Rooze, Marcel

2006-01-15

Controlled study, measuring head repositioning error (HRE) using an electrogoniometric device. To compare HRE in neutral position, axial rotation and complex postures of patients with whiplash-associated disorders (WAD) to that of control subjects. The presence of kinesthetic alterations in patients with WAD is controversial. In 26 control subjects and 29 patients with WAD (aged 22-74 years), head kinematics was sampled using a 3-dimensional electrogoniometer mounted using a harness and a helmet. All tasks were realized in seated position. The repositioning tasks included neutral repositioning after maximal flexion-extension, eyes open and blindfolded, repositioning at 50 degrees of axial rotation, and repositioning at 50 degrees of axial rotation combined to 20 degrees of ipsilateral bending. The flexion-extension, ipsilateral bending, and axial rotation components of HRE were considered. A multiple-way repeated-measures analysis of variance was used to compare tasks and groups. The WAD group displayed a reduced flexion-extension range (P = 1.9 x 10(-4)), and larger HRE during flexion-extension and repositioning tasks (P = 0.009) than controls. Neither group nor task affected maximal motion velocity. Neutral HRE of the flexion-extension component was larger in blindfolded condition (P = 0.03). Ipsilateral bending and axial rotation HRE components were smaller than the flexion-extension component (P = 7.1 x 10(-23)). For pure rotation repositioning, axial rotation HRE was significantly larger than flexion-extension and ipsilateral bending repositioning error (P = 3.0 x 10(-23)). Ipsilateral bending component of HRE was significantly larger combined tasks than for pure rotation tasks (P = 0.004). In patients with WAD, range of motion and head repositioning accuracy were reduced. However, the differences were small. Vision suppression and task type influenced HRE.

Shh/Boc Signaling Is Required for Sustained Generation of Ipsilateral Projecting Ganglion Cells in the Mouse Retina

PubMed Central

Sánchez-Camacho, Cristina; Carreres, M. Isabel; Herrera, Eloisa; Okada, Ami; Bovolenta, Paola

2013-01-01

Sonic Hedgehog (Shh) signaling is an important determinant of vertebrate retinal ganglion cell (RGC) development. In mice, there are two major RGC populations: (1) the Islet2-expressing contralateral projecting (c)RGCs, which both produce and respond to Shh; and (2) the Zic2-expressing ipsilateral projecting RGCs (iRGCs), which lack Shh expression. In contrast to cRGCs, iRGCs, which are generated in the ventrotemporal crescent (VTC) of the retina, specifically express Boc, a cell adhesion molecule that acts as a high-affinity receptor for Shh. In Boc−/− mutant mice, the ipsilateral projection is significantly decreased. Here, we demonstrate that this phenotype results, at least in part, from the misspecification of a proportion of iRGCs. In Boc−/− VTC, the number of Zic2-positive RGCs is reduced, whereas more Islet2/Shh-positive RGCs are observed, a phenotype also detected in Zic2 and Foxd1 null embryos. Consistent with this observation, organization of retinal projections at the dorsallateral geniculate nucleus is altered in Boc−/− mice. Analyses of the molecular and cellular consequences of introducing Shh into the developing VTC and Zic2 and Boc into the central retina indicate that Boc expression alone is in sufficient to fully activate the ipsilateral program and that Zic2 regulates Shh expression. Taking these data together, we propose that expression of Boc in cells from the VTC is required to sustain Zic2 expression, likely by regulating the levels of Shh signaling from the nearby cRGCs. Zic2, in turn, directly or indirectly, counteracts Shh and Islet2 expression in the VTC and activates the ipsilateral program. PMID:23678105

Prognostic significance of specific injury patterns in casualties of traffic-related accidents.

PubMed

Calosevic, Srdjan; Lovric, Zvonimir

2015-11-01

Fatal triad and ipsilateral dyad are patterns of pedestrian injuries related to significant mortality in traffic-related accidents. The aim of this research was to investigate the correlation between specific injury patterns and fatal outcome in other participants of traffic-related accidents. This was a retrospective study of traffic-related accidents in the broader area of the city of Osijek in a five-year period from 1995 to 1999. Autopsy results from the Institute of Pathology and Forensic Medicine of the Clinical Hospital Centre Osijek were analysed of individuals who died after their accident. The total severity of injuries was measured using the ISS. Logistic regression analysis was used for assessing the correlation between specific injury patterns and an early outcome from the severe injury. There were 213 individuals included in the study: 72 pedestrians and 141 other participants (drivers, assistant drivers, passengers, cyclists and motorcyclists). A total of129 individuals died on the spot and 84 died in the hospital during the first 48h. Femoral and pelvic fracture, fatal triad and both variants of ipsilateral dyad were related to higher ISS values. Ipsilateral fracture of upper and lower extremities (ipsilateral dyad 1) was associated with a 4.59 times higher risk of an immediate fatal outcome in the total sample. In pedestrians, the risk was 5.99 higher, and in other participants, the risk was 4.11 times higher. Specific skeletal injuries and injury patterns are a significant indicator for total injury severity and related poor prognosis for all participants of traffic-related injuries, not only for pedestrians. In this study, the ipsilateral fracture of upper and lower extremity was related to the largest total severity of injuries and the poorest prognosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Does the Dumbbell-Carrying Position Change the Muscle Activity in Split Squats and Walking Lunges?

PubMed

Stastny, Petr; Lehnert, Michal; Zaatar, Amr M Z; Svoboda, Zdenek; Xaverova, Zuzana

2015-11-01

The forward walking lunge (WL) and split squat (SSq) are similar exercises that have differences in the eccentric phase, and both can be performed in the ipsilateral or contralateral carrying conditions. This study aimed to determine the effects of dumbbell-carrying position on the kinematics and electromyographic (EMG) amplitudes of the gluteus medius (Gmed), vastus medialis (VM), vastus lateralis (VL), and biceps femoris during WLs and SSqs. The resistance-trained (RT) and the non-resistance-trained (NT) groups (both n = 14) performed ipsilateral WLs, contralateral WLs, ipsilateral SSqs, and contralateral SSqs in a randomized order in a simulated training session. The EMG amplitude, expressed as a percentage of the maximal voluntary isometric contraction (%MVIC), and the kinematics, expressed as the range of motion (ROM) of the hip and knee, were measured during 5 repetition maximum for both legs. The repeated measure analyses of variance showed significant differences between the RT and NT groups. The NT group showed a smaller knee flexion ROM (p < 0.001, η = 0.36) during both types of WLs, whereas the RT group showed a higher eccentric Gmed amplitude (p < 0.001, η = 0.46) during all exercises and a higher eccentric VL amplitude (p < 0.001, η = 0.63) during contralateral WLs. Further differences were found between contralateral and ipsilateral WLs in both the RT (p < 0.001, η = 0.69) and NT groups (p < 0.001, η = 0.80), and contralateral WLs resulted in higher eccentric Gmed amplitudes. Contralateral WLs highly activated the Gmed (90% MVIC); therefore, this exercise can increase the Gmed maximal strength. The ipsilateral loading condition did not increase the Gmed or VM activity in the RT or NT group.

Multicenter experience on eversion versus conventional carotid endarterectomy in symptomatic carotid artery stenosis: observations from the Stent-Protected Angioplasty Versus Carotid Endarterectomy (SPACE-1) trial.

PubMed

Demirel, Serdar; Attigah, Nicolas; Bruijnen, Hans; Ringleb, Peter; Eckstein, Hans-Henning; Fraedrich, Gustav; Böckler, Dittmar

2012-07-01

Carotid endarterectomy (CEA) is beneficial in patients with symptomatic carotid artery stenosis. However, randomized trials have not provided evidence concerning the optimal CEA technique, conventional or eversion. The outcome of 563 patients within the surgical randomization arm of the Stent-Protected Angioplasty versus Carotid Endarterectomy in Symptomatic Patients (SPACE-1) trial was analyzed by surgical technique subgroups: eversion endarterectomy versus conventional endarterectomy with patch angioplasty. The primary end point was ipsilateral stroke or death within 30 days after surgery. Secondary outcome events included perioperative adverse events and the 2-year risk of restenosis, stroke, and death. Both groups were similar in terms of demographic and other baseline clinical variables. Shunt frequency was higher in the conventional CEA group (65% versus 17%; P<0.0001). The risk of ipsilateral stroke or death within 30 days after surgery was significantly greater with eversion CEA (9% versus 3%; P=0.005). There were no statistically significant differences in the rate of perioperative secondary outcome events with the exception of a significantly higher risk of intraoperative ipsilateral stroke rate in the eversion CEA group (4% versus 0.3%; P=0.0035). The 2-year risk of ipsilateral stroke occurring after 30 days was significantly higher in the conventional CEA group (2.9% versus 0%; P=0.017). In patients with symptomatic carotid artery stenosis, conventional CEA appears to be associated with better periprocedural neurological outcome than eversion CEA. Eversion CEA, however, may be more effective for long-term prevention of ipsilateral stroke. These findings should be interpreted with caution noting the limitations of the post hoc, nonrandomized nature of the analysis.

The efficacy of a novel mobile phone application for goldmann ptosis visual field interpretation.

PubMed

Maamari, Robi N; D'Ambrosio, Michael V; Joseph, Jeffrey M; Tao, Jeremiah P

2014-01-01

To evaluate the efficacy of a novel mobile phone application that calculates superior visual field defects on Goldmann visual field charts. Experimental study in which the mobile phone application and 14 oculoplastic surgeons interpreted the superior visual field defect in 10 Goldmann charts. Percent error of the mobile phone application and the oculoplastic surgeons' estimates were calculated compared with computer software computation of the actual defects. Precision and time efficiency of the application were evaluated by processing the same Goldmann visual field chart 10 repeated times. The mobile phone application was associated with a mean percent error of 1.98% (95% confidence interval[CI], 0.87%-3.10%) in superior visual field defect calculation. The average mean percent error of the oculoplastic surgeons' visual estimates was 19.75% (95% CI, 14.39%-25.11%). Oculoplastic surgeons, on average, underestimated the defect in all 10 Goldmann charts. There was high interobserver variance among oculoplastic surgeons. The percent error of the 10 repeated measurements on a single chart was 0.93% (95% CI, 0.40%-1.46%). The average time to process 1 chart was 12.9 seconds (95% CI, 10.9-15.0 seconds). The mobile phone application was highly accurate, precise, and time-efficient in calculating the percent superior visual field defect using Goldmann charts. Oculoplastic surgeon visual interpretations were highly inaccurate, highly variable, and usually underestimated the field vision loss.

Optical cylinder designs to increase the field of vision in the osteo-odonto-keratoprosthesis.

PubMed

Hull, C C; Liu, C S; Sciscio, A; Eleftheriadis, H; Herold, J

2000-12-01

The single optical cylinders used in the osteo-odonto-keratoprosthesis (OOKP) are known to produce very small visual fields. Values of 40 degrees are typically quoted. The purpose of this paper is to present designs for new optical cylinders that significantly increase the field of view and therefore improve the visual rehabilitation of patients having an OOKP. Computer ray-tracing techniques were used to design and analyse improved one- and two-piece optical cylinders made from polymethyl methacrylate. All designs were required to have a potential visual acuity of 6/6 before consideration was given to the visual field and optimising off-axis image quality. Aspheric surfaces were used where this significantly improved off-axis image quality. Single optical cylinders, with increased posterior cylinder (intraocular) diameters, gave an increase in the theoretical visual field of 18% (from 76 degrees to 90 degrees) over current designs. Two-piece designs based on an inverted telephoto principle gave theoretical field angles over 120 degrees. Aspheric surfaces were shown to improve the off-axis image quality while maintaining a potential visual acuity of at least 6/6. This may well increase the measured visual field by improving the retinal illuminance off-axis. Results demonstrate that it is possible to significantly increase the theoretical maximum visual field through OOKP optical cylinders. Such designs will improve the visual rehabilitation of patients undergoing this procedure.

Learning to Recognize Patterns: Changes in the Visual Field with Familiarity

NASA Astrophysics Data System (ADS)

Bebko, James M.; Uchikawa, Keiji; Saida, Shinya; Ikeda, Mitsuo

1995-01-01

Two studies were conducted to investigate changes which take place in the visual information processing of novel stimuli as they become familiar. Japanese writing characters (Hiragana and Kanji) which were unfamiliar to two native English speaking subjects were presented using a moving window technique to restrict their visual fields. Study time for visual recognition was recorded across repeated sessions, and with varying visual field restrictions. The critical visual field was defined as the size of the visual field beyond which further increases did not improve the speed of recognition performance. In the first study, when the Hiragana patterns were novel, subjects needed to see about half of the entire pattern simultaneously to maintain optimal performance. However, the critical visual field size decreased as familiarity with the patterns increased. These results were replicated in the second study with more complex Kanji characters. In addition, the critical field size decreased as pattern complexity decreased. We propose a three component model of pattern perception. In the first stage a representation of the stimulus must be constructed by the subject, and restricting of the visual field interferes dramatically with this component when stimuli are unfamiliar. With increased familiarity, subjects become able to reconstruct a previous representation from very small, unique segments of the pattern, analogous to the informativeness areas hypothesized by Loftus and Mackworth [J. Exp. Psychol., 4 (1978) 565].

Driving with Binocular Visual Field Loss? A Study on a Supervised On-Road Parcours with Simultaneous Eye and Head Tracking

PubMed Central

Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

2014-01-01

Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs) that may critically interfere with quality of life and driving licensure. The aims of this study were (i) to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii) to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed) of ten patients with homonymous visual field defects (HP), including four patients with right (HR) and six patients with left homonymous visual field defects (HL), ten glaucoma patients (GP), and twenty age and gender-related ophthalmologically healthy control subjects (C) during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD) critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL) due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on the central area of the visual field than patients who failed the test. In addition, patients who passed the test performed more glances towards the area of their visual field defect. In conclusion, our findings support the hypothesis that the extent of visual field per se cannot predict driving fitness, because some patients with HVFDs and advanced glaucoma can compensate for their deficit by effective visual scanning. Head movements appeared to be superior to eye and shoulder movements in predicting the outcome of the driving test under the present study scenario. PMID:24523869

Differences in Visual-Spatial Input May Underlie Different Compression Properties of Firing Fields for Grid Cell Modules in Medial Entorhinal Cortex

PubMed Central

Raudies, Florian; Hasselmo, Michael E.

2015-01-01

Firing fields of grid cells in medial entorhinal cortex show compression or expansion after manipulations of the location of environmental barriers. This compression or expansion could be selective for individual grid cell modules with particular properties of spatial scaling. We present a model for differences in the response of modules to barrier location that arise from different mechanisms for the influence of visual features on the computation of location that drives grid cell firing patterns. These differences could arise from differences in the position of visual features within the visual field. When location was computed from the movement of visual features on the ground plane (optic flow) in the ventral visual field, this resulted in grid cell spatial firing that was not sensitive to barrier location in modules modeled with small spacing between grid cell firing fields. In contrast, when location was computed from static visual features on walls of barriers, i.e. in the more dorsal visual field, this resulted in grid cell spatial firing that compressed or expanded based on the barrier locations in modules modeled with large spacing between grid cell firing fields. This indicates that different grid cell modules might have differential properties for computing location based on visual cues, or the spatial radius of sensitivity to visual cues might differ between modules. PMID:26584432

Useful visual field in patients with schizophrenia: a choice reaction time study.

PubMed

Matsuda, Yukihisa; Matsui, Mie; Tonoya, Yasuhiro; Ebihara, Naokuni; Kurachi, Masayoshi

2011-04-01

This study examined the size of the useful visual field in patients (9 men, 6 women) with schizophrenia. A choice reaction task was conducted, and performances at 2.5, 5, 7, 10, and 25 degrees in both visual fields were measured. Three key findings were shown. First, patients had slower choice reaction times (choice RTs) than normal controls. Second, patients had slower choice RTs in the right visual field than in the left visual field. Third, patients and normal controls showed the same U-shaped choice RT pattern. The first and second findings were consistent with those of other studies. The third finding was a clear indication of the patients' performance in peripheral vision, and a comparison with normal controls suggested that there was no difference in the size of the useful visual field, at least within

Dosimetric comparison of 3D conformal, IMRT, and V-MAT techniques for accelerated partial-breast irradiation (APBI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Jian-Jian; Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai

2014-07-01

The purpose is to dosimetrically compare the following 3 delivery techniques: 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated arc therapy (IMRT), and volumetric-modulated arc therapy (V-MAT) in the treatment of accelerated partial-breast irradiation (APBI). Overall, 16 patients with T1/2N0 breast cancer were treated with 3D-CRT (multiple, noncoplanar photon fields) on the RTOG 0413 partial-breast trial. These cases were subsequently replanned using static gantry IMRT and V-MAT technology to understand dosimetric differences among these 3 techniques. Several dosimetric parameters were used in plan quality evaluation, including dose conformity index (CI) and dose-volume histogram analysis of normal tissue coverage. Quality assurance studies includingmore » gamma analysis were performed to compare the measured and calculated dose distributions. The IMRT and V-MAT plans gave more conformal target dose distributions than the 3D-CRT plans (p < 0.05 in CI). The volume of ipsilateral breast receiving 5 and 10 Gy was significantly less using the V-MAT technique than with either 3D-CRT or IMRT (p < 0.05). The maximum lung dose and the ipsilateral lung volume receiving 10 (V{sub 10}) or 20 Gy (V{sub 20}) were significantly less with both V-MAT and IMRT (p < 0.05). The IMRT technique was superior to 3D-CRT and V-MAT of low dose distributions in ipsilateral lung (p < 0.05 in V{sub 5} and D{sub 5}). The total mean monitor units (MUs) for V-MAT (621.0 ± 111.9) were 12.2% less than those for 3D-CRT (707.3 ± 130.9) and 46.5% less than those for IMRT (1161.4 ± 315.6) (p < 0.05). The average machine delivery time was 1.5 ± 0.2 minutes for the V-MAT plans, 7.0 ± 1.6 minutes for the 3D-CRT plans, and 11.5 ± 1.9 minutes for the IMRT plans, demonstrating much less delivery time for V-MAT. Based on this preliminary study, V-MAT and IMRT techniques offer improved dose conformity as compared with 3D-CRT techniques without increasing dose to the ipsilateral lung. In terms of MU and delivery time, V-MAT is significantly more efficient for APBI than for conventional 3D-CRT and static-beam IMRT.« less

Maintaining perceptual constancy while remaining vigilant: left hemisphere change blindness and right hemisphere vigilance.

PubMed

Vos, Leia; Whitman, Douglas

2014-01-01

A considerable literature suggests that the right hemisphere is dominant in vigilance for novel and survival-related stimuli, such as predators, across a wide range of species. In contrast to vigilance for change, change blindness is a failure to detect obvious changes in a visual scene when they are obscured by a disruption in scene presentation. We studied lateralised change detection using a series of scenes with salient changes in either the left or right visual fields. In Study 1 left visual field changes were detected more rapidly than right visual field changes, confirming a right hemisphere advantage for change detection. Increasing stimulus difficulty resulted in greater right visual field detections and left hemisphere detection was more likely when change occurred in the right visual field on a prior trial. In Study 2 an intervening distractor task disrupted the influence of prior trials. Again, faster detection speeds were observed for the left visual field changes with a shift to a right visual field advantage with increasing time-to-detection. This suggests that a right hemisphere role for vigilance, or catching attention, and a left hemisphere role for target evaluation, or maintaining attention, is present at the earliest stage of change detection.

Parry-Romberg syndrome: intracranial MRI appearances.

PubMed

Moko, Sheree Bernadette; Mistry, Yezdi; Blandin de Chalain, Tristan Maurice

2003-10-01

To gain further insight into the pathogenesis of Parry-Romberg syndrome, a sporadic disease of unknown aetiology characterized by progressive wasting of one side of the face. Cranial MRI was performed in 10 patients with Parry-Romberg syndrome. The central nervous system findings are correlated to clinical findings and a review of the literature. Three patients with a history of migraine had abnormal brain findings confined to the cerebral hemisphere ipsilateral to the facial hemiatrophy. Two patients without CNS symptoms had intracranial changes, one ipsilateral, the other both ipsilateral and contralateral to the facial hemiatrophy, on MRI. These changes consisted of either intracerebral atrophy or white matter hyperintensity. Five patients without CNS symptoms had no pathological intracranial MRI appearances. A significant number of patients with Parry-Romberg syndrome may have underlying brain involvement. These findings are consistent with previous reports.

Ureteric entrapment in sacroiliac joint causing hydroureter and ipsilateral kidney hypertrophy.

PubMed

Otsuru, Yurie; Kondo, Chuichi; Hara, Shohei; Takahashi, Hideo; Matsuno, Kenjiro

2018-06-01

A unilateral megaureter was found in an elderly female cadaver during routine dissection. The left proximal ureter, which was thick and convolute, descended and entered into the pelvic cavity, where the distal ureter was attached to the posterior pelvic wall at the inlet level. Removal of connective tissue surrounding the attached region revealed ureteric entrapment in the sacroiliac joint. The ipsilateral kidney, from which the megaureter originated, showed no pelvicalyceal dilatation. In contrast, the left kidney was enlarged, weighing 24% more than the right kidney. Differences in the upper urinary system between the obstructed and normal sides were examined in terms of gross anatomy, measurements, and histology. Although ureteric obstruction frequently causes hydroureter and hydronephrosis, the present case is very rare as the incomplete obstruction may have stimulated ipsilateral kidney growth, instead of contralateral compensatory augmentation.

Trans-Splenic Portal Vein Embolization: A Technique to Avoid Damage to the Future Liver Remnant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarwar, Ammar, E-mail: asarwar@bidmc.harvard.edu; Brook, Olga R.; Weinstein, Jeffrey L.

2016-10-15

Portal vein embolization (PVE) induces hypertrophy of the future liver remnant (FLR) in patients undergoing extensive hepatic resection. Portal vein access for PVE via the ipsilateral hepatic lobe (designated for resection) places veins targeted for embolization at acute angles to the access site requiring reverse curve catheters for access. This approach also involves access close to tumors in the ipsilateral lobe and requires care to avoid traversing tumor. Alternatively, a contralateral approach (through the FLR) risks damage to the FLR due to iatrogenic trauma or non-target embolization. Two patients successfully underwent PVE via trans-splenic portal vein access, allowing easy accessmore » to the ipsilateral portal veins and eliminating risk of damage to FLR. Technique and advantages of trans-splenic portal vein access to perform PVE are described.« less

Vestibular responses in the macaque pedunculopontine nucleus and central mesencephalic reticular formation

PubMed Central

Aravamuthan, Bhooma R.; Angelaki, Dora E.

2012-01-01

The pedunculopontine nucleus (PPN) and central mesencephalic reticular formation (cMRF) both send projections and receive input from areas with known vestibular responses. Noting their connections with the basal ganglia, the locomotor disturbances that occur following lesions of the PPN or cMRF, and the encouraging results of PPN deep brain stimulation in Parkinson’s disease patients, both the PPN and cMRF have been linked to motor control. In order to determine the existence of and characterize vestibular responses in the PPN and cMRF, we recorded single neurons from both structures during vertical and horizontal rotation, translation, and visual pursuit stimuli. The majority of PPN cells (72.5%) were vestibular-only cells that responded exclusively to rotation and translation stimuli but not visual pursuit. Visual pursuit responses were much more prevalent in the cMRF (57.1%) though close to half of cMRF cells were vestibular-only cells (41.1%). Directional preferences also differed between the PPN, which was preferentially modulated during nose-down pitch, and cMRF, which was preferentially modulated during ipsilateral yaw rotation. Finally, amplitude responses were similar between the PPN and cMRF during rotation and pursuit stimuli, but PPN responses to translation were of higher amplitude than cMRF responses. Taken together with their connections to the vestibular circuit, these results implicate the PPN and cMRF in the processing of vestibular stimuli and suggest important roles for both in responding to motion perturbations like falls and turns. PMID:22864184

Robust Representation of Stable Object Values in the Oculomotor Basal Ganglia

PubMed Central

Yasuda, Masaharu; Yamamoto, Shinya; Hikosaka, Okihide

2012-01-01

Our gaze tends to be directed to objects previously associated with rewards. Such object values change flexibly or remain stable. Here we present evidence that the monkey substantia nigra pars reticulata (SNr) in the basal ganglia represents stable, rather than flexible, object values. After across-day learning of object–reward association, SNr neurons gradually showed a response bias to surprisingly many visual objects: inhibition to high-valued objects and excitation to low-valued objects. Many of these neurons were shown to project to the ipsilateral superior colliculus. This neuronal bias remained intact even after >100 d without further learning. In parallel with the neuronal bias, the monkeys tended to look at high-valued objects. The neuronal and behavioral biases were present even if no value was associated during testing. These results suggest that SNr neurons bias the gaze toward objects that were consistently associated with high values in one’s history. PMID:23175843

Subcortical functional reorganization due to early blindness

PubMed Central

Jiang, Fang; Fine, Ione; Watkins, Kate E.; Bridge, Holly

2015-01-01

Lack of visual input early in life results in occipital cortical responses to auditory and tactile stimuli. However, it remains unclear whether cross-modal plasticity also occurs in subcortical pathways. With the use of functional magnetic resonance imaging, auditory responses were compared across individuals with congenital anophthalmia (absence of eyes), those with early onset (in the first few years of life) blindness, and normally sighted individuals. We find that the superior colliculus, a “visual” subcortical structure, is recruited by the auditory system in congenital and early onset blindness. Additionally, auditory subcortical responses to monaural stimuli were altered as a result of blindness. Specifically, responses in the auditory thalamus were equally strong to contralateral and ipsilateral stimulation in both groups of blind subjects, whereas sighted controls showed stronger responses to contralateral stimulation. These findings suggest that early blindness results in substantial reorganization of subcortical auditory responses. PMID:25673746

38 CFR 4.76a - Computation of average concentric contraction of visual fields.

Code of Federal Regulations, 2010 CFR

2010-07-01

... concentric contraction of visual fields. 4.76a Section 4.76a Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES Disability Ratings The Organs of Special Sense § 4.76a Computation of average concentric contraction of visual fields. Table III—Normal Visual...

Simulated visual field loss does not alter turning coordination in healthy young adults.

PubMed

Murray, Nicholas G; Ponce de Leon, Marlina; Ambati, V N Pradeep; Saucedo, Fabricio; Kennedy, Evan; Reed-Jones, Rebecca J

2014-01-01

Turning, while walking, is an important component of adaptive locomotion. Current hypotheses regarding the motor control of body segment coordination during turning suggest heavy influence of visual information. The authors aimed to examine whether visual field impairment (central loss or peripheral loss) affects body segment coordination during walking turns in healthy young adults. No significant differences in the onset time of segments or intersegment coordination were observed because of visual field occlusion. These results suggest that healthy young adults can use visual information obtained from central and peripheral visual fields interchangeably, pointing to flexibility of visuomotor control in healthy young adults. Further study in populations with chronic visual impairment and those with turning difficulties are warranted.

Ethanol and Mesolimbic Serotonin/Dopamine Interactions Via 5-HT1B Receptors

DTIC Science & Technology

2006-03-01

baclofen , a GABAB receptor agonist, into the VTA probe and the response of extracellular DA in the ipsilateral NACC was determined. A significant...decrease (50% deduction) in extracellular DA in the ipsilateral NACC after perfusion with baclofen was considered an appropriate implantation of the...the VTA with baclofen were included in data analyses. Approximately 70% of the animals that had undergone surgery had both probes correctly implanted

Traumatic ipsilateral multiple open metatarsal and calcaneal fractures with first metatarsophalangeal joint dislocation: a case report.

PubMed

Ozkan, Namik Kemal; Unay, Koray; Cift, Hakan; Eceviz, Engin; Ozkan, Korhan

2010-06-01

A 17-year-old man fell from a height of 10 m onto his right forefoot and sustained ipsilateral calcaneal, comminuted cuboid, and second, third, and fourth metatarsal neck fractures and first metatarsophalangeal joint open dislocation. This report discusses this rare injury. The authors believe that initial debridement with immediate surgical fixation and reduction with appropriate antibiotic treatment saved the patient's extremity.

Projections of the optic tectum and the mesencephalic nucleus of the trigeminal nerve in the tegu lizard (Tupinambis nigropunctatus).

PubMed

Ebbesson, S O

1981-01-01

Fibers undergoing Wallerian degeneration following tectal lesions were demonstrated with the Nauta and Fink-Heimer methods and traced to their termination. Four of the five distinct fiber paths originating in the optic tectum appear related to vision, while one is related to the mesencephalic nucleus of the trigeminus. The latter component of the tectal efferents distributes fibers to 1) the main sensory nucleus of the trigeminus, 2) the motor nucleus of the trigeminus, 3) the nucleus of tractus solitarius, and 4) the intermediate gray of the cervical spinal cord. The principal ascending bundle projects to the nucleus rotundus, three components of the ventral geniculate nucleus and the nucleus ventromedialis anterior ipsilaterally, before it crosses in the supraoptic commissure and terminates in the contralateral nucleus rotundus, ventral geniculate nucleus and a hitherto unnamed region dorsal to the nucleus of the posterior accessory optic tract. Fibers leaving the tectum dorso-medially terminate in the posterodorsal nucleus ipsilaterally and the stratum griseum periventriculare of the contralateral tectum. The descending fiber paths terminate in medial reticular cell groups and the rostral spinal cord contralaterally and in the torus and the lateral reticular regions ipsilaterally. The ipsilateral fascicle also issues fibers to the magnocellular nucleus isthmi.

Cervical hip fractures do not occur in arthrotic joints. A clinicoradiographic study of 256 patients.

PubMed

Dretakis, E K; Steriopoulos, K A; Kontakis, G M; Giaourakis, G; Economakis, G; Dretakis, K E

1998-08-01

We studied endogenic factors for the occurrence of cervical hip fractures in 256 patients. 230 underwent hemiarthroplasty, and 26 were treated with internal fixation or without surgery. The condition of the fractured hip and of the ipsilateral knee, as well as the mobility of the patient before the fracture, were studied in all 256 patients. The removed femoral heads were examined, photographed and radiographs were taken with sensitive film. The acetabulum and the femoral head were macroscopically normal in all 230 cases and there was no radiographic evidence of arthrosis. 64% of the patients were fully mobile before the fracture, 34% were mobile with the aid of a cane and 2% were dependent. In 88%, the ipsilateral knee was normal both clinically and radiographically, and in 12%, there was moderate arthrosis. When comparing the mobility before the fracture and the condition of the ipsilateral hip and knee in 100 patients having a cervical fracture with 100 patients having a trochanteric fracture matched for age and sex, we found that a normal hip joint was sine qua non while a normal ipsilateral knee and a fully mobile individual were important additional conditions for the occurrence of a cervical hip fracture, instead of a trochanteric one, after a fall in an elderly person.

Predictors of thyroid gland involvement in hypopharyngeal squamous cell carcinoma.

PubMed

Chang, Jae Won; Koh, Yoon Woo; Chung, Woong Youn; Hong, Soon Won; Choi, Eun Chang

2015-05-01

Decision to perform concurrent ipsilateral thyroidectomy on patients with hypopharyngeal cancer is important, and unnecessary thyroidectomy should be avoided if oncologically feasible. We hypothesized that concurrent ipsilateral thyroidectomy is not routinely required to prevent occult metastasis. This study aimed to determine the prevalence of histological thyroid invasion in patients with hypopharyngeal cancer, and to refine the indications for prophylactic ipsilateral thyroidectomy in patients with hypopharyngeal cancer. A retrospective review of the medical records from the Department of Otolaryngology at Yonsei University College of Medicine was conducted from January 1994 to December 2009. A total of 49 patients underwent laryngopharyngectomy with thyroidectomy as a primary treatment of hypopharyngeal cancer. The incidence of thyroid gland involvement was 10.2%. The most common route of invasion was direct extension through the thyroid cartilage. Thyroid cartilage invasion (p=0.034) was the most significant factor associated with thyroid invasion. Disease-specific survival at 5 years was lower in patients with than without thyroid gland invasion (26.7% vs. 55.2%, respectively; p=0.032). Disease-free survival at 5 years was also lower in patients with than without thyroid gland invasion (20.0% vs. 52.1%, respectively; p=0.024). Ipsilateral thyroidectomy in combination with total laryngopharyngectomy is indicated when invasion of the thyroid cartilage is suspected in patients with hypopharyngeal cancer.

Chronic hyperperfusion and angiogenesis follow subacute hypoperfusion in the thalamus of rats with focal cerebral ischemia

PubMed Central

Hayward, Nick MEA; Yanev, Pavel; Haapasalo, Annakaisa; Miettinen, Riitta; Hiltunen, Mikko; Gröhn, Olli; Jolkkonen, Jukka

2011-01-01

Cerebral blood flow (CBF) is disrupted after focal ischemia in rats. We examined long-term hemodynamic and cerebrovascular changes in the rat thalamus after focal cerebral ischemia. Cerebral blood flow quantified by arterial spin labeling magnetic resonance imaging was decreased in the ipsilateral and contralateral thalamus 2 days after cerebral ischemia. Partial thalamic CBF recovery occurred by day 7, then the ipsilateral thalamus was chronically hyperperfused at 30 days and 3 months compared with its contralateral side. This contrasted with permanent hypoperfusion in the ipsilateral cortex. Angiogenesis was indicated by endothelial cell (RECA-1) immunohistochemistry that showed increased blood vessel branching in the ipsilateral thalamus at the end of the 3-month follow-up. Only transient thalamic IgG extravasation was observed, indicating that the blood–brain barrier was intact after day 2. Angiogenesis was preceded by transiently altered expression levels of cadherin family adhesion molecules, cadherin-7, protocadherin-1, and protocadherin-17. In conclusion, thalamic pathology after focal cerebral ischemia involved long-term hemodynamic changes and angiogenesis preceded by altered expression of vascular adhesion factors. Postischemic angiogenesis in the thalamus represents a novel type of remote plasticity, which may support removal of necrotic brain tissue and aid functional recovery. PMID:21081957

Responses of dorsal spinal cord blood flow to noxious mechanical stimulation of the skin in anesthetized rats.

PubMed

Toda, Hiroko; Maruyama, Hitoshi; Budgell, Brian; Kurosawa, Mieko

2008-08-01

In urethane-anesthetized, artificially ventilated rats, alterations in dorsal spinal cord blood flow (SCBF) at the L4-6 level were measured with laser Doppler flowmetry in response to noxious mechanical cutaneous stimulation (pinching) of either a forepaw or a hindpaw. The stimulation was delivered ipsilaterally or contralaterally to the site of blood flow measurement. Pinching of the forepaw or the hindpaw on either side increased mean arterial pressure (MAP) to the same degree. However, the SCBF response to pinching of the ipsilateral hindpaw was significantly greater than that to other stimulations. These responses were not influenced by denervation of the baroreceptors. The responses of SCBF to pinching of the ipsilateral hindpaw persisted both after treatment with phenoxybenzamine and after spinalization at the C1-2 level, whereas the responses to pinching at other sites disappeared. The responses of MAP to stimulation at all four sites became negligible after treatment with phenoxybenzamine and after spinalization at the C1-2 level. These results indicate that noxious mechanical stimulation of the skin produces increases in SCBF via two mechanisms: one is via an elevation of systemic arterial pressure; the other is via a localized spinal mechanism evoked by ipsilateral, segmental inputs.

Hip rotation range of motion in sitting and prone positions in healthy Japanese adults

PubMed Central

Han, Heonsoo; Kubo, Akira; Kurosawa, Kazuo; Maruichi, Shizuka; Maruyama, Hitoshi

2015-01-01

[Purpose] The aim of this study was to elucidate the difference in hip external and internal rotation ranges of motion (ROM) between the prone and sitting positions. [Subjects] The subjects included 151 students. [Methods] Hip rotational ROM was measured with the subjects in the prone and sitting positions. Two-way repeated measures analysis of variance (ANOVA) was used to analyze ipsilateral hip rotation ROM in the prone and sitting positions in males and females. The total ipsilateral hip rotation ROM was calculated by adding the measured values for external and internal rotations. [Results] Ipsilateral hip rotation ROM revealed significant differences between two positions for both left and right internal and external rotations. Hip rotation ROM was significantly higher in the prone position than in the sitting position. Hip rotation ROM significantly differed between the men and women. Hip external rotation ROM was significantly higher in both positions in men; conversely, hip internal rotation ROM was significantly higher in both positions in women. [Conclusion] Hip rotation ROM significantly differed between the sexes and between the sitting and prone positions. Total ipsilateral hip rotation ROM, total angle of external rotation, and total angle of internal rotation of the left and right hips greatly varied, suggesting that hip joint rotational ROM is widely distributed. PMID:25729186

Dissecting the contribution of knee joint NGF to spinal nociceptive sensitization in a model of OA pain in the rat

PubMed Central

Sagar, D.R.; Nwosu, L.; Walsh, D.A.; Chapman, V.

2015-01-01

Summary Objective Although analgesic approaches targeting nerve growth factor (NGF) for the treatment of osteoarthritis (OA) pain remain of clinical interest, neurophysiological mechanisms by which NGF contribute to OA pain remain unclear. We investigated the impact of local elevation of knee joint NGF on knee joint, vs remote (hindpaw), evoked responses of spinal neurones in a rodent model of OA pain. Design In vivo spinal electrophysiology was carried out in anaesthetised rats with established pain behaviour and joint pathology following intra-articular injection of monosodium iodoacetate (MIA), vs injection of saline. Neuronal responses to knee joint extension and flexion, mechanical punctate stimulation of the peripheral receptive fields over the knee and at a remote site (ipsilateral hind paw) were studied before, and following, intra-articular injection of NGF (10 μg/50 μl) or saline. Results MIA-injected rats exhibited significant local (knee joint) and remote (lowered hindpaw withdrawal thresholds) changes in pain behaviour, and joint pathology. Intra-articular injection of NGF significantly (P < 0.05) increased knee extension-evoked firing of spinal neurones and the size of the peripheral receptive fields of spinal neurones (100% increase) over the knee joint in MIA rats, compared to controls. Intra-articular NGF injection did not significantly alter responses of spinal neurones following noxious stimulation of the ipsilateral hind paw in MIA-injected rats. Conclusion The facilitatory effects of intra-articular injection of NGF on spinal neurones receiving input from the knee joint provide a mechanistic basis for NGF mediated augmentation of OA knee pain, however additional mechanisms may contribute to the spread of pain to remote sites. PMID:25623624

Radiotherapy alone or combined with chemotherapy as definitive treatment for squamous cell carcinoma of the tonsil.

PubMed

Kennedy, William R; Herman, Michael P; Deraniyagala, Rohan L; Amdur, Robert J; Werning, John W; Dziegielewski, Peter; Kirwan, Jessica; Morris, Christopher G; Mendenhall, William M

2016-08-01

This study is aimed at updating our institution's experience with definitive radiotherapy (RT) for squamous cell carcinoma of the tonsil. We reviewed 531 patients treated between 1983 and 2012 with definitive RT for squamous cell carcinoma of the tonsil. Of these, 179 patients were treated with either induction (n = 19) or concomitant (n = 160) chemotherapy. Planned neck dissection was performed on 217 patients: unilaterally in 199 and bilaterally in 18 patients. Median follow-up was 5.2 years for all patients (range 0.1-31.6 years) and 8.2 years for living patients (range 1.9-31.6 years). The 5-year local control rates by T stage were as follows: T1, 94 %; T2, 87 %; T3 79 %; T4, 70 %; and overall, 83 %. Multivariate analysis revealed that local control was significantly influenced by T stage and neck dissection. The 5-year cause-specific survival rates by overall stage were as follows: I, 94 %; II, 88 %; III, 87 %; IVA, 75 %; IVB, 52 %; and overall, 78 %. Multivariate analysis revealed that cause-specific survival was significantly influenced by T stage, N stage, overall stage, fractionation, neck dissection, sex, and ethnicity. Of 77 patients treated with ipsilateral fields only, contralateral neck failure occurred in 1 %. The rate of severe complications was 12 %. Definitive RT for patients with tonsillar squamous cell carcinoma provides control rates equivalent to other modalities with a comparatively low incidence of late complications. Patients with anterior tonsillar pillar or tonsillar fossa primaries that are well lateralized with no base of tongue or soft palate extension may be treated with ipsilateral fields.

Dissecting the contribution of knee joint NGF to spinal nociceptive sensitization in a model of OA pain in the rat.

PubMed

Sagar, D R; Nwosu, L; Walsh, D A; Chapman, V

2015-06-01

Although analgesic approaches targeting nerve growth factor (NGF) for the treatment of osteoarthritis (OA) pain remain of clinical interest, neurophysiological mechanisms by which NGF contribute to OA pain remain unclear. We investigated the impact of local elevation of knee joint NGF on knee joint, vs remote (hindpaw), evoked responses of spinal neurones in a rodent model of OA pain. In vivo spinal electrophysiology was carried out in anaesthetised rats with established pain behaviour and joint pathology following intra-articular injection of monosodium iodoacetate (MIA), vs injection of saline. Neuronal responses to knee joint extension and flexion, mechanical punctate stimulation of the peripheral receptive fields over the knee and at a remote site (ipsilateral hind paw) were studied before, and following, intra-articular injection of NGF (10 μg/50 μl) or saline. MIA-injected rats exhibited significant local (knee joint) and remote (lowered hindpaw withdrawal thresholds) changes in pain behaviour, and joint pathology. Intra-articular injection of NGF significantly (P < 0.05) increased knee extension-evoked firing of spinal neurones and the size of the peripheral receptive fields of spinal neurones (100% increase) over the knee joint in MIA rats, compared to controls. Intra-articular NGF injection did not significantly alter responses of spinal neurones following noxious stimulation of the ipsilateral hind paw in MIA-injected rats. The facilitatory effects of intra-articular injection of NGF on spinal neurones receiving input from the knee joint provide a mechanistic basis for NGF mediated augmentation of OA knee pain, however additional mechanisms may contribute to the spread of pain to remote sites. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Early detection of glaucoma by means of a novel 3D computer‐automated visual field test

PubMed Central

Nazemi, Paul P; Fink, Wolfgang; Sadun, Alfredo A; Francis, Brian; Minckler, Donald

2007-01-01

Purpose A recently devised 3D computer‐automated threshold Amsler grid test was used to identify early and distinctive defects in people with suspected glaucoma. Further, the location, shape and depth of these field defects were characterised. Finally, the visual fields were compared with those obtained by standard automated perimetry. Patients and methods Glaucoma suspects were defined as those having elevated intraocular pressure (>21 mm Hg) or cup‐to‐disc ratio of >0.5. 33 patients and 66 eyes with risk factors for glaucoma were examined. 15 patients and 23 eyes with no risk factors were tested as controls. The recently developed 3D computer‐automated threshold Amsler grid test was used. The test exhibits a grid on a computer screen at a preselected greyscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. The 5‐minute test required that the patients repeatedly outline scotomas on a touch screen with varied displays of contrast while maintaining their gaze on a central fixation marker. A 3D depiction of the visual field defects was then obtained that was further characterised by the location, shape and depth of the scotomas. The exam was repeated three times per eye. The results were compared to Humphrey visual field tests (ie, achromatic standard or SITA standard 30‐2 or 24‐2). Results In this pilot study 79% of the eyes tested in the glaucoma‐suspect group repeatedly demonstrated visual field loss with the 3D perimetry. The 3D depictions of visual field loss associated with these risk factors were all characteristic of or compatible with glaucoma. 71% of the eyes demonstrated arcuate defects or a nasal step. Constricted visual fields were shown in 29% of the eyes. No visual field changes were detected in the control group. Conclusions The 3D computer‐automated threshold Amsler grid test may demonstrate visual field abnormalities characteristic of glaucoma in glaucoma suspects with normal achromatic Humphrey visual field testing. This test may be used as a screening tool for the early detection of glaucoma. PMID:17504855

Internal Carotid Artery Stenosis and Collateral Recruitment in Stroke Patients.

PubMed

Dankbaar, Jan W; Kerckhoffs, Kelly G P; Horsch, Alexander D; van der Schaaf, Irene C; Kappelle, L Jaap; Velthuis, Birgitta K

2017-04-24

Leptomeningeal collaterals improve outcome in stroke patients. There is great individual variability in their extent. Internal carotid artery (ICA) stenosis may lead to more extensive recruitment of leptomeningeal collaterals. The purpose of this study was to evaluate the association of pre-existing ICA stenosis with leptomeningeal collateral filling visualized with computed tomography perfusion (CTP). From a prospective acute ischemic stroke cohort, patients were included with an M1 middle cerebral artery (MCA) occlusion and absent ipsilateral, extracranial ICA occlusion. ICA stenosis was determined on admission CT angiography (CTA). Leptomeningeal collaterals were graded as good (>50%) or poor (≤50%) collateral filling in the affected MCA territory on CTP-derived vessel images of the admission scan. The association between ipsilateral ICA stenosis ≥70% and extent of collateral filling was analyzed using logistic regression. In a multivariable analysis the odds ratio (OR) of ICA stenosis ≥70% was adjusted for complete circle of Willis, gender and age. We included 188 patients in our analyses, 50 (26.6%) patients were classified as having poor collateral filling and 138 (73.4%) as good. Of the patients 4 with poor collateral filling had an ICA stenosis ≥70% and 14 with good collateral filling. Unadjusted and adjusted ORs of ICA stenosis ≥70% for good collateral filling were 1.30 (0.41-4.15) and 2.67 (0.81-8.77), respectively. Patients with poor collateral filling had a significantly worse outcome (90-day modified Rankin scale 3-6; 80% versus 52%, p = 0.001). No association was found between pre-existing ICA stenosis and extent of CTP derived collateral filling in patients with an M1 occlusion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strittmatter, S.M.; Lo, M.M.S.; Javitch, J.A.

The authors have visualized angiotensin-converting enzyme (ACE; dipeptidyl carboxypeptidase, peptidylpeptide hydrolase, EC 3.4.15.1) in rat brain by in vitro (/sup 3/H)captopril autoradiography. (/sup 3/H)Captopril binding to brain slices displays a high affinity (K/sub d/ = 1.8 x 10/sup -9/ M) and a pharmacological profile similar to that of ACE activity. Very high densities of (/sup 3/H)captopril binding were found in the choroid plexus and the subfornical organ. High densities were present in the caudate putamen and substantia nigra, zona reticulata. Moderate levels were found in the entopeduncular nucleus, globus pallidus, and median eminence of the hypothalamus. Lower levels were detectablemore » in the supraoptic and paraventricular nuclei of the hypothalamus, the media habenula, the median preoptic area, and the locus coeruleus. Injection of ibotenic acid or colchicine into the caudate putamen decreased (/sup 3/H)captopril-associated autoradiographic grains by 85% in the ipsilateral caudate putamen and by > 50% in the ipsilateral substantia nigra. Thus, ACE in the substantia nigra is located on presynaptic terminals of axons originating from the caudate putamen, and ACE in the caudate putamen is situated in neuronal perikarya or at the terminals of striatal interneurons. The lack of effect of similar injections into the substantia nigra confirmed that the caudate putamen injections did not cause trans-synaptic changes. The presence of (/sup 3/H)captopril binding is consistent with an ACE-mediated production of angiotensin II in some brain regions. Although (/sup 3/H)captopril autoradiography reveals ACE in a striatonigral pathway, there is no evidence for angiotensin II involvement in such a neuronal pathway. 26 references, 4 figures, 2 tables.« less

D-(/sup 3/H)aspartate retrograde labelling of callosal and association neurons of somatosensory areas I and II of cats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbaresi, P.; Fabri, M.; Conti, F.

Experiments were carried out on cats to ascertain whether corticocortical neurons of somatosensory areas I (SI) and II (SII) could be labelled by retrograde axonal transport of D-(/sup 3/H)aspartate (D-(/sup 3/H)Asp). This tritiated enantiomer of the amino acid aspartate is (1) taken up selectively by axon terminals of neurons releasing aspartate and/or glutamate as excitatory neurotransmitter, (2) retrogradely transported and accumulated in perikarya, (3) not metabolized, and (4) visualized by autoradiography. A solution of D-(/sup 3/H)Asp was injected in eight cats in the trunk and forelimb zones of SI (two cats) or in the forelimb zone of SII (six cats).more » In order to compare the labelling patterns obtained with D-(/sup 3/H)Asp with those resulting after injection of a nonselective neuronal tracer, horseradish peroxidase (HRP) was delivered mixed with the radioactive tracer in seven of the eight cats. Furthermore, six additional animals received HRP injections in SI (three cats; trunk and forelimb zones) or SII (three cats; forelimb zone). D-(/sup 3/H)Asp retrograde labelling of perikarya was absent from the ipsilateral thalamus of all cats injected with the radioactive tracer but a dense terminal plexus of anterogradely labelled corticothalamic fibers from SI and SII was observed, overlapping the distribution area of thalamocortical neurons retrogradely labelled with HRP from the same areas. D-(/sup 3/H)Asp-labelled neurones were present in ipsilateral SII (SII-SI association neurones) in cats injected in SI. In these animals a bundle of radioactive fibres was observed in the rostral portion of the corpus callosum entering the contralateral hemisphere. There, neurones retrogradely labelled with silver grains were present in SI (SI-SI callosal neurons).« less

Comparison of the post-operative analgesic effect of paravertebral block, pectoral nerve block and local infiltration in patients undergoing modified radical mastectomy: A randomised double-blind trial

PubMed Central

Syal, Kartik; Chandel, Ankita

2017-01-01

Background and Aims: Paravertebral block, pectoral nerve (Pecs) block and wound infiltration are three modalities for post-operative analgesia following breast surgery. This study compares the analgesic efficacy of these techniques for post-operative analgesia. Methods: Sixty-five patients with American Society of Anesthesiologists’ physical status 1 or 2 undergoing modified radical mastectomy with axillary dissection were recruited for the study. All patients received 21 mL 0.5% bupivacaine with adrenaline in the technique which was performed at the end of the surgery prior to extubation. Patients in Group 1 (local anaesthetic [LA], n = 22) received infiltration at the incision site after surgery, Group 2 patients (paravertebral block [PVB], n = 22) received ultrasound-guided ipsilateral paravertebral block while Group 3 patients [PECT] (n = 21) received ultrasound-guided ipsilateral Pecs blocks I and II. Patients were evaluated for pain scores at 0, 2, 4, 6, 12 and 24 h, duration of post-operative analgesia and rescue analgesic doses required. Non-normally distributed data were analysed using the Kruskal-Wallis test and Analysis of variance for normal distribution. Results: The post-operative visual analogue scale scores were lower in PVB group compared with others at 0, 2, 4, 12 and 24 h (P < 0.05). Mean duration of analgesia was significantly prolonged in PVB group (P < 0.001) with lesser rescue analgesic consumption up to 24 h. Conclusion: Ultrasound-guided paravertebral block reduces post-operative pain scores, prolongs the duration of analgesia and decreases demands for rescue analgesics in the first 24 h of post-operative period compared to ultrasound-guided Pecs block and local infiltration block. PMID:28890559

Comparison of the post-operative analgesic effect of paravertebral block, pectoral nerve block and local infiltration in patients undergoing modified radical mastectomy: A randomised double-blind trial.

PubMed

Syal, Kartik; Chandel, Ankita

2017-08-01

Paravertebral block, pectoral nerve (Pecs) block and wound infiltration are three modalities for post-operative analgesia following breast surgery. This study compares the analgesic efficacy of these techniques for post-operative analgesia. Sixty-five patients with American Society of Anesthesiologists' physical status 1 or 2 undergoing modified radical mastectomy with axillary dissection were recruited for the study. All patients received 21 mL 0.5% bupivacaine with adrenaline in the technique which was performed at the end of the surgery prior to extubation. Patients in Group 1 (local anaesthetic [LA], n = 22) received infiltration at the incision site after surgery, Group 2 patients (paravertebral block [PVB], n = 22) received ultrasound-guided ipsilateral paravertebral block while Group 3 patients [PECT] ( n = 21) received ultrasound-guided ipsilateral Pecs blocks I and II. Patients were evaluated for pain scores at 0, 2, 4, 6, 12 and 24 h, duration of post-operative analgesia and rescue analgesic doses required. Non-normally distributed data were analysed using the Kruskal-Wallis test and Analysis of variance for normal distribution. The post-operative visual analogue scale scores were lower in PVB group compared with others at 0, 2, 4, 12 and 24 h ( P < 0.05). Mean duration of analgesia was significantly prolonged in PVB group ( P < 0.001) with lesser rescue analgesic consumption up to 24 h. Ultrasound-guided paravertebral block reduces post-operative pain scores, prolongs the duration of analgesia and decreases demands for rescue analgesics in the first 24 h of post-operative period compared to ultrasound-guided Pecs block and local infiltration block.

Plaque Echolucency and Stroke Risk in Asymptomatic Carotid Stenosis: A Systematic Review and Meta-Analysis

PubMed Central

Gupta, Ajay; Kesavabhotla, Kartik; Baradaran, Hediyeh; Kamel, Hooman; Pandya, Ankur; Giambrone, Ashley E.; Wright, Drew; Pain, Kevin J.; Mtui, Edward E.; Suri, Jasjit S.; Sanelli, Pina C.; Mushlin, Alvin I.

2014-01-01

Background and Purpose Ultrasonographic plaque echolucency has been studied as a stroke risk marker in carotid atherosclerotic disease. We performed a systematic review and meta-analysis to summarize the association between ultrasound determined carotid plaque echolucency and future ipsilateral stroke risk. Methods We searched the medical literature for studies evaluating the association between carotid plaque echolucency and future stroke in asymptomatic patients. We included prospective observational studies with stroke outcome ascertainment after baseline carotid plaque echolucency assessment. We performed a meta-analysis and assessed study heterogeneity and publication bias. We also performed subgroup analyses limited to patients with stenosis ≥50%, studies in which plaque echolucency was determined via subjective visual interpretation, studies with a relatively lower risk of bias, and studies published after the year 2000. Results We analyzed data from 7 studies on 7557 subjects with a mean follow up of 37.2 months. We found a significant positive relationship between predominantly echolucent (compared to predominantly echogenic) plaques and the risk of future ipsilateral stroke across all stenosis severities (0-99%) (relative risk [RR], 2.31, 95% CI, 1.58-3.39, P<.001) and in subjects with ≥50% stenosis (RR, 2.61 95% CI, 1.47-4.63, P=.001). A statistically significant increased RR for future stroke was preserved in all additional subgroup analyses. No statistically significant heterogeneity or publication bias was present in any of the meta-analyses. Conclusions The presence of ultrasound-determined carotid plaque echolucency provides predictive information in asymptomatic carotid artery stenosis beyond luminal stenosis. However, the magnitude of the increased risk is not sufficient on its own to identify patients likely to benefit from surgical revascularization. PMID:25406150

Organization of area hV5/MT+ in subjects with homonymous visual field defects.

PubMed

Papanikolaou, Amalia; Keliris, Georgios A; Papageorgiou, T Dorina; Schiefer, Ulrich; Logothetis, Nikos K; Smirnakis, Stelios M

2018-04-06

Damage to the primary visual cortex (V1) leads to a visual field loss (scotoma) in the retinotopically corresponding part of the visual field. Nonetheless, a small amount of residual visual sensitivity persists within the blind field. This residual capacity has been linked to activity observed in the middle temporal area complex (V5/MT+). However, it remains unknown whether the organization of hV5/MT+ changes following early visual cortical lesions. We studied the organization of area hV5/MT+ of five patients with dense homonymous defects in a quadrant of the visual field as a result of partial V1+ or optic radiation lesions. To do so, we developed a new method, which models the boundaries of population receptive fields directly from the BOLD signal of each voxel in the visual cortex. We found responses in hV5/MT+ arising inside the scotoma for all patients and identified two possible sources of activation: 1) responses might originate from partially lesioned parts of area V1 corresponding to the scotoma, and 2) responses can also originate independent of area V1 input suggesting the existence of functional V1-bypassing pathways. Apparently, visually driven activity observed in hV5/MT+ is not sufficient to mediate conscious vision. More surprisingly, visually driven activity in corresponding regions of V1 and early extrastriate areas including hV5/MT+ did not guarantee visual perception in the group of patients with post-geniculate lesions that we examined. This suggests that the fine coordination of visual activity patterns across visual areas may be an important determinant of whether visual perception persists following visual cortical lesions. Copyright © 2018 Elsevier Inc. All rights reserved.

Visual field examination method using virtual reality glasses compared with the Humphrey perimeter.

PubMed

Tsapakis, Stylianos; Papaconstantinou, Dimitrios; Diagourtas, Andreas; Droutsas, Konstantinos; Andreanos, Konstantinos; Moschos, Marilita M; Brouzas, Dimitrios

2017-01-01

To present a visual field examination method using virtual reality glasses and evaluate the reliability of the method by comparing the results with those of the Humphrey perimeter. Virtual reality glasses, a smartphone with a 6 inch display, and software that implements a fast-threshold 3 dB step staircase algorithm for the central 24° of visual field (52 points) were used to test 20 eyes of 10 patients, who were tested in a random and consecutive order as they appeared in our glaucoma department. The results were compared with those obtained from the same patients using the Humphrey perimeter. High correlation coefficient ( r =0.808, P <0.0001) was found between the virtual reality visual field test and the Humphrey perimeter visual field. Visual field examination results using virtual reality glasses have a high correlation with the Humphrey perimeter allowing the method to be suitable for probable clinical use.

Vision-related fitness to drive mobility scooters: A practical driving test.

PubMed

Cordes, Christina; Heutink, Joost; Tucha, Oliver M; Brookhuis, Karel A; Brouwer, Wiebo H; Melis-Dankers, Bart J M

2017-03-06

To investigate practical fitness to drive mobility scooters, comparing visually impaired participants with healthy controls. Between-subjects design. Forty-six visually impaired (13 with very low visual acuity, 10 with low visual acuity, 11 with peripheral field defects, 12 with multiple visual impairment) and 35 normal-sighted controls. Participants completed a practical mobility scooter test-drive, which was recorded on video. Two independent occupational therapists specialized in orientation and mobility evaluated the videos systematically. Approximately 90% of the visually impaired participants passed the driving test. On average, participants with visual impairments performed worse than normal-sighted controls, but were judged sufficiently safe. In particular, difficulties were observed in participants with peripheral visual field defects and those with a combination of low visual acuity and visual field defects. People with visual impairment are, in practice, fit to drive mobility scooters; thus visual impairment on its own should not be viewed as a determinant of safety to drive mobility scooters. However, special attention should be paid to individuals with visual field defects with or without a combined low visual acuity. The use of an individual practical fitness-to-drive test is advised.

Red square test for visual field screening. A sensitive and simple bedside test.

PubMed

Mandahl, A

1994-12-01

A reliable bedside test for screening of visual field defects is a valuable tool in the examination of patients with a putative disease affecting the sensory visual pathways. Conventional methods such as Donders' confrontation method, counting fingers in the visual field periphery, of two-hand confrontation are not sufficiently sensitive to detect minor but nevertheless serious visual field defects. More sensitive methods requiring only simple tools are also described. In this study, a test card with four red squares surrounding a fixation target, a black dot, with a total test area of about 11 x 12.5 degrees at a distance of 30 cm, was designed for testing experience of red colour saturation in four quadrants, red square test. The Goldmann visual field was used as reference. 125 consecutive patients with pituitary adenoma (159 eyes), craniopharyngeoma (9 eyes), meningeoma (21 eyes), vascular hemisphere lesion (40 eyes), hemisphere tumour (10 eyes) and hemisphere abscess (2 eyes) were examined. The Goldmann visual field and red square test were pathological in pituitary adenomas in 35%, in craniopharyngeomas in 44%, in meningeomas in 52% and in hemisphere tumours or abscess in 100% of the eyes. Among these, no false-normal or false-pathological tests were found. However, in vascular hemisphere disease the corresponding figures were Goldmann visual field 90% and red square test 85%. The 5% difference (4 eyes) was due to Goldmann visual field defects strictly peripheral to the central 15 degrees. These defects were easily diagnosed with two-hand confrontation and

Visual field defects of the contralateral eye of non-arteritic ischemic anterior optic neuropathy: are they related to sleep apnea?

PubMed

Aptel, Florent; Aryal-Charles, Nischal; Tamisier, Renaud; Pépin, Jean-Louis; Lesoin, Antoine; Chiquet, Christophe

2017-06-01

To evaluate whether obstructive sleep apnea (OSA) is responsible for the visual field defects found in the fellow eyes of patients with non-arteritic ischemic optic neuropathy (NAION). Prospective cross-sectional study. The visual fields of the fellow eyes of NAION subjects with OSA were compared to the visual fields of control OSA patients matched for OSA severity. All patients underwent comprehensive ophthalmological and general examination including Humphrey 24.2 SITA-Standard visual field and polysomnography. Visual field defects were classified according the Ischemic Optic Neuropathy Decompression Trial (IONDT) classification. From a cohort of 78 consecutive subjects with NAION, 34 unaffected fellow eyes were compared to 34 control eyes of subjects matched for OSA severity (apnea-hypopnea index [AHI] 35.5 ± 11.6 vs 35.4 ± 9.4 events per hour, respectively, p = 0.63). After adjustment for age and body mass index, all visual field parameters were significantly different between the NAION fellow eyes and those of the control OSA groups, including mean deviation (-4.5 ± 3.7 vs -1.3 ± 1.8 dB, respectively, p < 0.05), visual field index (91.6 ± 10 vs 97.4 ± 3.5%, respectively, p = 0.002), pattern standard deviation (3.7 ± 2.3 vs 2.5 ± 2 dB, respectively, p = 0.015), and number of subjects with at least one defect on the IONDT classification (20 vs 10, respectively, p < 0.05). OSA alone does not explain the visual field defects frequently found in the fellow eyes of NAION patients.

Sparse coding can predict primary visual cortex receptive field changes induced by abnormal visual input.

PubMed

Hunt, Jonathan J; Dayan, Peter; Goodhill, Geoffrey J

2013-01-01

Receptive fields acquired through unsupervised learning of sparse representations of natural scenes have similar properties to primary visual cortex (V1) simple cell receptive fields. However, what drives in vivo development of receptive fields remains controversial. The strongest evidence for the importance of sensory experience in visual development comes from receptive field changes in animals reared with abnormal visual input. However, most sparse coding accounts have considered only normal visual input and the development of monocular receptive fields. Here, we applied three sparse coding models to binocular receptive field development across six abnormal rearing conditions. In every condition, the changes in receptive field properties previously observed experimentally were matched to a similar and highly faithful degree by all the models, suggesting that early sensory development can indeed be understood in terms of an impetus towards sparsity. As previously predicted in the literature, we found that asymmetries in inter-ocular correlation across orientations lead to orientation-specific binocular receptive fields. Finally we used our models to design a novel stimulus that, if present during rearing, is predicted by the sparsity principle to lead robustly to radically abnormal receptive fields.

Sparse Coding Can Predict Primary Visual Cortex Receptive Field Changes Induced by Abnormal Visual Input

PubMed Central

Hunt, Jonathan J.; Dayan, Peter; Goodhill, Geoffrey J.

2013-01-01

Receptive fields acquired through unsupervised learning of sparse representations of natural scenes have similar properties to primary visual cortex (V1) simple cell receptive fields. However, what drives in vivo development of receptive fields remains controversial. The strongest evidence for the importance of sensory experience in visual development comes from receptive field changes in animals reared with abnormal visual input. However, most sparse coding accounts have considered only normal visual input and the development of monocular receptive fields. Here, we applied three sparse coding models to binocular receptive field development across six abnormal rearing conditions. In every condition, the changes in receptive field properties previously observed experimentally were matched to a similar and highly faithful degree by all the models, suggesting that early sensory development can indeed be understood in terms of an impetus towards sparsity. As previously predicted in the literature, we found that asymmetries in inter-ocular correlation across orientations lead to orientation-specific binocular receptive fields. Finally we used our models to design a novel stimulus that, if present during rearing, is predicted by the sparsity principle to lead robustly to radically abnormal receptive fields. PMID:23675290

Comparison of visual field training for hemianopia with active versus sham transcranial direct cortical stimulation.

PubMed

Plow, Ela B; Obretenova, Souzana N; Fregni, Felipe; Pascual-Leone, Alvaro; Merabet, Lotfi B

2012-01-01

Vision Restoration Therapy (VRT) aims to improve visual field function by systematically training regions of residual vision associated with the activity of suboptimal firing neurons within the occipital cortex. Transcranial direct current stimulation (tDCS) has been shown to modulate cortical excitability. Assess the possible efficacy of tDCS combined with VRT. The authors conducted a randomized, double-blind, demonstration-of-concept pilot study where participants were assigned to either VRT and tDCS or VRT and sham. The anode was placed over the occipital pole to target both affected and unaffected lobes. One hour training sessions were carried out 3 times per week for 3 months in a laboratory. Outcome measures included objective and subjective changes in visual field, recording of visual fixation performance, and vision-related activities of daily living (ADLs) and quality of life (QOL). Although 12 participants were enrolled, only 8 could be analyzed. The VRT and tDCS group demonstrated significantly greater expansion in visual field and improvement on ADLs compared with the VRT and sham group. Contrary to expectations, subjective perception of visual field change was greater in the VRT and sham group. QOL did not change for either group. The observed changes in visual field were unrelated to compensatory eye movements, as shown with fixation monitoring. The combination of occipital cortical tDCS with visual field rehabilitation appears to enhance visual functional outcomes compared with visual rehabilitation alone. TDCS may enhance inherent mechanisms of plasticity associated with training.

An optimized content-aware image retargeting method: toward expanding the perceived visual field of the high-density retinal prosthesis recipients

NASA Astrophysics Data System (ADS)

Li, Heng; Zeng, Yajie; Lu, Zhuofan; Cao, Xiaofei; Su, Xiaofan; Sui, Xiaohong; Wang, Jing; Chai, Xinyu

2018-04-01

Objective. Retinal prosthesis devices have shown great value in restoring some sight for individuals with profoundly impaired vision, but the visual acuity and visual field provided by prostheses greatly limit recipients’ visual experience. In this paper, we employ computer vision approaches to seek to expand the perceptible visual field in patients implanted potentially with a high-density retinal prosthesis while maintaining visual acuity as much as possible. Approach. We propose an optimized content-aware image retargeting method, by introducing salient object detection based on color and intensity-difference contrast, aiming to remap important information of a scene into a small visual field and preserve their original scale as much as possible. It may improve prosthetic recipients’ perceived visual field and aid in performing some visual tasks (e.g. object detection and object recognition). To verify our method, psychophysical experiments, detecting object number and recognizing objects, are conducted under simulated prosthetic vision. As control, we use three other image retargeting techniques, including Cropping, Scaling, and seam-assisted shrinkability. Main results. Results show that our method outperforms in preserving more key features and has significantly higher recognition accuracy in comparison with other three image retargeting methods under the condition of small visual field and low-resolution. Significance. The proposed method is beneficial to expand the perceived visual field of prosthesis recipients and improve their object detection and recognition performance. It suggests that our method may provide an effective option for image processing module in future high-density retinal implants.

A new isocentric technique for exact geometric matching in the radiotherapy of the breast and ipsilateral supraclavicular fossa using dual asymmetric jaws.

PubMed

Romeo, Nando

2012-10-01

In some clinical situations breast or chest wall radiotherapy for cancer is given in association with supraclavicular fossa irradiation. Often the treatment is delivered by two tangential fields to the breast or chest wall and an anterior field that irradiates the supraclavicular region. The tissue between the breast or chest wall and the supraclavicular region may be under or overdosed, because of the junction between the two tangential fields and the anterior field. To present a new isocentric technique for exact geometric matching between the two tangential fields and the anterior field. Patients are positioned with both arms raised. Using three-dimensional trigonometry, two half-fields, with isocenter between the breast and the supraclavicular region, are easily matched. The tangential fields have a collimator rotation to protect the lung without additional shielding. The correct gantry, collimator and couch positions are defined for the anterior field to match the tangential fields. A general formula for exact geometric matching in radiotherapy of the breast and supraclavicular fossa is presented. The method does not require additional shielding to eliminate divergence other than the four independent jaws. The result is simple to implement in modern delivery facilities. Copyright © 2011 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

[Correlation of intraocular pressure variation after visual field examination with 24-hour intraocular pressure variations in primary open-angle glaucoma].

PubMed

Noro, Takahiko; Nakamoto, Kenji; Sato, Makoto; Yasuda, Noriko; Ito, Yoshinori; Ogawa, Shumpei; Nakano, Tadashi; Tsuneoka, Hiroshi

2014-10-01

We retrospectively examined intraocular pressure variations after visual field examination in primary open angle glaucoma (POAG), together with its influencing factors and its association with 24-hour intraocular pressure variations. Subjects were 94 eyes (52 POAG patients) subjected to measurements of 24-hour intraocular pressure and of changes in intraocular pressure after visual field examination using a Humphrey Visual Field Analyzer. Subjects were classified into three groups according to the magnitude of variation (large, intermediate and small), and 24-hour intraocular pressure variations were compared among the three groups. Factors influencing intraocular pressure variations after visual field examination and those associated with the large variation group were investigated. Average intraocular pressure variation after visual field examination was -0.28 ± 1.90 (range - 6.0(-) + 5.0) mmHg. No significant influencing factors were identified. The intraocular pressure at 3 a.m. was significantly higher in the large variation group than other two groups (p < 0.001). Central corneal thickness was correlated with the large variation group (odds ratio = 1.04; 95% confidence interval, 1.01-1.07 ; p = 0.02). No particular tendencies in intraocular pressure variations were found after visual field examination. Increases in intraocular pressure during the night might be associated with large intraocular pressure variations after visual field examination.

Eccentric correction for off-axis vision in central visual field loss.

PubMed

Gustafsson, Jörgen; Unsbo, Peter

2003-07-01

Subjects with absolute central visual field loss use eccentric fixation and magnifying devices to utilize their residual vision. This preliminary study investigated the importance of an accurate eccentric correction of off-axis refractive errors to optimize the residual visual function for these subjects. Photorefraction using the PowerRefractor instrument was used to evaluate the ametropia in eccentric fixation angles. Methods were adapted for measuring visual acuity outside the macula using filtered optotypes from high-pass resolution perimetry. Optical corrections were implemented, and the visual function of subjects with central visual field loss was measured with and without eccentric correction. Of the seven cases reported, five experienced an improvement in visual function in their preferred retinal locus with eccentric refraction. The main result was that optical correction for better image quality on the peripheral retina is important for the vision of subjects with central visual field loss, objectively as well as subjectively.

Rehabilitation of Reading and Visual Exploration in Visual Field Disorders: Transfer or Specificity?

ERIC Educational Resources Information Center

Schuett, Susanne; Heywood, Charles A.; Kentridge, Robert W.; Dauner, Ruth; Zihl, Josef

2012-01-01

Reading and visual exploration impairments in unilateral homonymous visual field disorders are frequent and disabling consequences of acquired brain injury. Compensatory therapies have been developed, which allow patients to regain sufficient reading and visual exploration performance through systematic oculomotor training. However, it is still…

Effects of Peripheral Visual Field Loss on Eye Movements During Visual Search

PubMed Central

Wiecek, Emily; Pasquale, Louis R.; Fiser, Jozsef; Dakin, Steven; Bex, Peter J.

2012-01-01

Natural vision involves sequential eye movements that bring the fovea to locations selected by peripheral vision. How peripheral visual field loss (PVFL) affects this process is not well understood. We examine how the location and extent of PVFL affects eye movement behavior in a naturalistic visual search task. Ten patients with PVFL and 13 normally sighted subjects with full visual fields (FVF) completed 30 visual searches monocularly. Subjects located a 4° × 4° target, pseudo-randomly selected within a 26° × 11° natural image. Eye positions were recorded at 50 Hz. Search duration, fixation duration, saccade size, and number of saccades per trial were not significantly different between PVFL and FVF groups (p > 0.1). A χ2 test showed that the distributions of saccade directions for PVFL and FVL subjects were significantly different in 8 out of 10 cases (p < 0.01). Humphrey Visual Field pattern deviations for each subject were compared with the spatial distribution of eye movement directions. There were no significant correlations between saccade directional bias and visual field sensitivity across the 10 patients. Visual search performance was not significantly affected by PVFL. An analysis of eye movement directions revealed patients with PVFL show a biased directional distribution that was not directly related to the locus of vision loss, challenging feed-forward models of eye movement control. Consequently, many patients do not optimally compensate for visual field loss during visual search. PMID:23162511

Learning to Read Vertical Text in Peripheral Vision

PubMed Central

Subramanian, Ahalya; Legge, Gordon E.; Wagoner, Gunther Harrison; Yu, Deyue

2014-01-01

Purpose English–language text is almost always written horizontally. Text can be formatted to run vertically, but this is seldom used. Several studies have found that horizontal text can be read faster than vertical text in the central visual field. No studies have investigated the peripheral visual field. Studies have also concluded that training can improve reading speed in the peripheral visual field for horizontal text. We aimed to establish whether the horizontal vertical differences are maintained and if training can improve vertical reading in the peripheral visual field. Methods Eight normally sighted young adults participated in the first study. Rapid Serial Visual Presentation (RSVP) reading speed was measured for horizontal and vertical text in the central visual field and at 10° eccentricity in the upper or lower (horizontal text), and right or left (vertical text) visual fields. Twenty-one normally sighted young adults split equally between 2 training and 1 control group participated in the second study. Training consisted of RSVP reading either using vertical text in the left visual field or horizontal text in the inferior visual field. Subjects trained daily over 4 days. Pre and post horizontal and vertical RSVP reading speeds were carried out for all groups. For the training groups these measurements were repeated 1 week and 1 month post training. Results Prior to training, RSVP reading speeds were faster for horizontal text in the central and peripheral visual fields when compared to vertical text. Training vertical reading improved vertical reading speeds by an average factor of 2.8. There was partial transfer of training to the opposite (right) hemifield. The training effects were retained for up to a month. Conclusions RSVP training can improve RSVP vertical text reading in peripheral vision. These findings may have implications for patients with macular degeneration or hemianopic field loss. PMID:25062130

Visual function, driving safety, and the elderly.

PubMed

Keltner, J L; Johnson, C A

1987-09-01

The authors have conducted a survey of the Departments of Motor Vehicles in all 50 states, the District of Columbia, and Puerto Rico requesting information about the visual standards, accidents, and conviction rates for different age groups. In addition, we have reviewed the literature on visual function and traffic safety. Elderly drivers have a greater number of vision problems that affect visual acuity and/or peripheral visual fields. Although the elderly are responsible for a small percentage of the total number of traffic accidents, the types of accidents they are involved in (e.g., failure to yield the right-of-way, intersection collisions, left turns onto crossing streets) may be related to peripheral and central visual field problems. Because age-related changes in performance occur at different rates for various individuals, licensing of the elderly driver should be based on functional abilities rather than age. Based on information currently available, we can make the following recommendations: (1) periodic evaluations of visual acuity and visual fields should be performed every 1 to 2 years in the population over age 65; (2) drivers of any age with multiple accidents or moving violations should have visual acuity and visual fields evaluated; and (3) a system should be developed for physicians to report patients with potentially unsafe visual function. The authors believe that these recommendations may help to reduce the number of traffic accidents that result from peripheral visual field deficits.

Unilateral pigmentary retinopathy--a review of literature and case presentation.

PubMed

Stamate, Alina-Cristina; Burcea, Marian; Zemba, Mihail

2016-01-01

To report a rare case of unilateral pigmentary retinopathy and describe the clinical and visual field characteristics of this particular case. We present the case of a 30-year-old male patient with a gradual loss of the visual field on his left eye (LE) for the past 10 years, with further gradual painless loss of his central visual field in the last year, and no similar symptoms in his right eye. His past medical and ocular history were unremarkable. No family history of acquired or inherited diseases was determined. Based on the history, clinical findings, and visual field examination, the diagnosis of unilateral pigmentary retinopathy was established. Visual acuity and visual field in the left eye (LE) were severely affected, while in the right eye (RE), they were completely normal. In this case, distinct features of pigmentary retinopathy were observed only in one eye, with the fellow eye being unaffected. The diagnosis requires a long follow-up period, visual field and electrophysiological testing to rule out a delayed onset of a bilateral form of pigmentary retinopathy.

Vision restoration therapy does not benefit from costimulation: A pilot study.

PubMed

Kasten, Erich; Bunzenthal, Ulrike; Müller-Oehring, Eva M; Mueller, Iris; Sabel, Bernhard A

2007-08-01

Visual field deficits in patients have long been considered to be nontreatable, but in previous studies we have found an enlargement of the intact visual field following vision restoration therapy (VRT). In the present pilot study, we wished to determine whether a double-stimulation approach would facilitate visual field enlargements beyond those achieved by the single-stimulus paradigm used in standard VRT. This was motivated by the findings that following visual cortex injury in animals, the size of receptive fields could be enlarged by systematic costimulation, where two stimuli were used to excite visual cortex neurons (Eysel, Eyding, & Schweigart, 1998). Patients (n = 23) with stable homonymous field deficits after trauma, cerebral ischemia, or hemorrhage (lesion age > 6 months) carried out either (a) standard VRT with a single stimulation (n = 9), or vision therapy with (b) a parallel costimulation (n = 7) or (c) a moving costimulation paradigm (n = 7). Training was carried out twice daily for 30 min over a 3-month period. Before and after therapy, visual fields were tested with 30 degrees and 90 degrees Tübinger automatic perimetry (TAP) and with high-resolution perimetry (HRP). Eye movements were recorded with an eye tracking system. When data of all three types of visual field training were pooled, we found significant improvements of stimulus detection in HRP (4.2%) and fewer misses within the central 30 degrees perimetrically (-3.7% right eye, OD, or -4.4% left eye, OS). However, the type of training did not make any difference such that the three training groups profited equally. A more detailed analysis of trained versus untrained visual field areas in 16 patients revealed a superiority of the trained area of only 1.1% in HRP and between 3.5% (OS) and 4.4% (OD) in TAP. Spatial attention and alertness improved significantly in all three groups and correlated significantly with visual field enlargements. While vision training had no influence on the patient's testimonials concerning their visual abilities, the patients significantly improved in a practical paper-and-pencil number tracking task (Zahlen-Verbindungs Test; ZVT). Visual field enlargement does not benefit from a double-stimulation paradigm, but visual attention seems to play an important role in vision restoration. The improvements in trained as well as in untrained areas are explained by top-down attentional control mechanisms interacting with local visual cortex plasticity.

Slow changing postural cues cancel visual field dependence on self-tilt detection.

PubMed

Scotto Di Cesare, C; Macaluso, T; Mestre, D R; Bringoux, L

2015-01-01

Interindividual differences influence the multisensory integration process involved in spatial perception. Here, we assessed the effect of visual field dependence on self-tilt detection relative to upright, as a function of static vs. slow changing visual or postural cues. To that aim, we manipulated slow rotations (i.e., 0.05° s(-1)) of the body and/or the visual scene in pitch. Participants had to indicate whether they felt being tilted forward at successive angles. Results show that thresholds for self-tilt detection substantially differed between visual field dependent/independent subjects, when only the visual scene was rotated. This difference was no longer present when the body was actually rotated, whatever the visual scene condition (i.e., absent, static or rotated relative to the observer). These results suggest that the cancellation of visual field dependence by dynamic postural cues may rely on a multisensory reweighting process, where slow changing vestibular/somatosensory inputs may prevail over visual inputs. Copyright © 2014 Elsevier B.V. All rights reserved.

Art in the eye of the beholder: the perception of art during monocular viewing.

PubMed

Finney, Glen Raymond; Heilman, Kenneth M

2008-03-01

To explore whether monocular viewing affects judgment of art. Each superior colliculus receives optic nerve fibers primarily from the contralateral eye, and visual input to each colliculus activates the ipsilateral hemisphere. In previous studies, monocular viewing influenced performance on visual-spatial and verbal memory tasks. Eight college-educated subjects, 6 men and 2 women, monocularly viewed 10 paintings with the right eye and another 10 with the left. Subjects had not previously seen the paintings. Each time, 5 paintings were abstract expressionist and 5 were impressionist. The orders of eye viewing and painting viewed were pseudorandomized and counterbalanced. Subjects rated on a 1 to 10 scale 4 qualities of the paintings: representation, aesthetics (beauty), novelty, and closure (completeness). Paintings in the abstract expressionist style had a significant difference in the rating of novelty; the paintings were rated more novel when viewed with the left eye than with the right eye. There was a trend for rating paintings as having more closure when viewing with the right eye than with the left. Impressionist paintings show no differences. Monocular viewing influences artistic judgments; novelty being rated higher when viewed with the left eye. Asymmetric projections from each eye and hemispheric specialization are posited to explain these differences.

Man with a Swollen Eye: Nonspecific Orbital Inflammation in an Adult in the Emergency Department.

PubMed

Zhang, Xiao Chi; Statler, Brittney; Suner, Selim; Lloyd, Maureen; Curley, David; Migliori, Michael E

2018-07-01

Nonspecific orbital inflammation (NSOI) is a rare idiopathic ocular pathology characterized by unilateral, painful orbital swelling without identifiable infectious or systemic disorders, which can be complicated by optic nerve compromise. A 50-year-old man presented to the Emergency Department with recurring, progressive painless left eye swelling, decreased visual acuity, and binocular diplopia in the absence of trauma, infection, or known malignancy. His physical examination was notable for left-sided decreased visual acuity, an afferent pupillary defect, severe left eye proptosis and chemosis, and restricted extraocular movements; his dilatated funduscopic examination was notable for ipsilateral retinal folds within the macula, concerning for a disruption between the sclera and the retina. Ocular examination of the right eye was unremarkable. Laboratory data were unrevealing. Gadolinium-enhanced magnetic resonance imaging showed marked thickening of the left extraocular muscles associated with proptosis, dense inflammatory infiltration of the orbital fat, and characteristics consistent with perineuritis. The patient was diagnosed with NSOI with optic neuritis and admitted for systemic steroid therapy; he was discharged on hospital day 2 after receiving high-dose intravenous (i.v.) methylprednisolone with significant improvement. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: NSOI is a rare and idiopathic ocular emergency, with clinical mimicry resembling a broad spectrum of systemic diseases such as malignancy, autoimmune diseases, endocrine disorders, and infection. Initial work-up for new-onset ocular proptosis should include comprehensive laboratory testing and gadolinium-enhanced magnetic resonance imaging. Timely evaluation by an ophthalmologist is crucial to assess for optic nerve involvement. Signs of optic nerve compromise include decreased visual acuity, afferent pupillary defect, or decreased color saturation. Patients with optic nerve compromise require admission for aggressive anti-inflammatory therapy with i.v. steroids in an attempt to reduce risk of long-term visual sequelae. Our case demonstrates a severe presentation of this disorder and exhibits remarkable visual recovery after 48 h of systemic i.v. steroid treatment. Published by Elsevier Inc.

Consolidation of visual associative long-term memory in the temporal cortex of primates.

PubMed

Miyashita, Y; Kameyama, M; Hasegawa, I; Fukushima, T

1998-01-01

Neuropsychological theories have proposed a critical role for the interaction between the medial temporal lobe and the neocortex in the formation of long-term memory for facts and events, which has often been tested by learning of a series of paired words or figures in humans. We have examined neural mechanisms underlying the memory "consolidation" process by single-unit recording and molecular biological methods in an animal model of a visual pair-association task in monkeys. In our previous studies, we found that long-term associative representations of visual objects are acquired through learning in the neural network of the anterior inferior temporal (IT) cortex. In this article, we propose the hypothesis that limbic neurons undergo rapid modification of synaptic connectivity and provide backward signals that guide the reorganization of neocortical neural circuits. Two experiments tested this hypothesis: (1) we examined the role of the backward connections from the medial temporal lobe to the IT cortex by injecting ibotenic acid into the entorhinal and perirhinal cortices, which provided massive backward projections ipsilaterally to the IT cortex. We found that the limbic lesion disrupted the associative code of the IT neurons between the paired associates, without impairing the visual response to each stimulus. (2) We then tested the first half of this hypothesis by detecting the expression of immediate-early genes in the monkey temporal cortex. We found specific expression of zif268 during the learning of a new set of paired associates in the pair-association task, most intensively in area 36 of the perirhinal cortex. All these results with the visual pair-association task support our hypothesis and demonstrate that the consolidation process, which was first proposed on the basis of clinico-psychological evidence, can now be examined in primates using neurophysiolocical and molecular biological approaches. Copyright 1998 Academic Press.

Aging and feature search: the effect of search area.

PubMed

Burton-Danner, K; Owsley, C; Jackson, G R

2001-01-01

The preattentive system involves the rapid parallel processing of visual information in the visual scene so that attention can be directed to meaningful objects and locations in the environment. This study used the feature search methodology to examine whether there are aging-related deficits in parallel-processing capabilities when older adults are required to visually search a large area of the visual field. Like young subjects, older subjects displayed flat, near-zero slopes for the Reaction Time x Set Size function when searching over a broad area (30 degrees radius) of the visual field, implying parallel processing of the visual display. These same older subjects exhibited impairment in another task, also dependent on parallel processing, performed over the same broad field area; this task, called the useful field of view test, has more complex task demands. Results imply that aging-related breakdowns of parallel processing over a large visual field area are not likely to emerge when required responses are simple, there is only one task to perform, and there is no limitation on visual inspection time.

[Retinotopic mapping of the human visual cortex with functional magnetic resonance imaging - basic principles, current developments and ophthalmological perspectives].

PubMed

Hoffmann, M B; Kaule, F; Grzeschik, R; Behrens-Baumann, W; Wolynski, B

2011-07-01

Since its initial introduction in the mid-1990 s, retinotopic mapping of the human visual cortex, based on functional magnetic resonance imaging (fMRI), has contributed greatly to our understanding of the human visual system. Multiple cortical visual field representations have been demonstrated and thus numerous visual areas identified. The organisation of specific areas has been detailed and the impact of pathophysiologies of the visual system on the cortical organisation uncovered. These results are based on investigations at a magnetic field strength of 3 Tesla or less. In a field-strength comparison between 3 and 7 Tesla, it was demonstrated that retinotopic mapping benefits from a magnetic field strength of 7 Tesla. Specifically, the visual areas can be mapped with high spatial resolution for a detailed analysis of the visual field maps. Applications of fMRI-based retinotopic mapping in ophthalmological research hold promise to further our understanding of plasticity in the human visual cortex. This is highlighted by pioneering studies in patients with macular dysfunction or misrouted optic nerves. © Georg Thieme Verlag KG Stuttgart · New York.

Experimental study of hemodynamics in the circle of willis

PubMed Central

2015-01-01

Background The Circle of Willis (CoW) is an important collateral pathway of the cerebral blood flow. An experimental study of the cerebral blood flow (CBF) distribution in different anatomical variations may help to a better understanding of the collateral mechanism of the CoW. Methods An in-vitro test rig was developed to simulate the physiological cerebral blood flow in the CoW. Ten anatomical variations were considered in this study, include a set of different degrees of stenosis in L-ICA and L-ICA occlusion coexist with common anatomical variations. Volume flow rates of efferent arteries and pressure signals at the end of communicating arteries of each case were recorded. Physiological pressure waveforms were applied as inlet boundary condition. Results In the development of L-ICA stenosis, the total CBF decreases with the increase of stenosis degree. The blood supply of ipsilateral middle cerebral artery (MCA) was affected most by the stenosis of L-ICA. Anterior communicating artery (ACoA) and ipsilateral posterior communicating artery (PCoA) function as important collateral pathways of cerebral collateral circulation when unilateral stenosis occurred. The blood supply of anterior cerebral circulation was compensated by the posterior cerebral circulation through ipsilateral PCoA when L-ICA stenosis degree is greater than 40% and the affected side was compensated immediately by the unaffected side through ACoA. Blood flow of the anterior circulation and the total CBF reached the minimum among all cases studied when L-ICA occlusion coexist with the absence of PCoA. Conclusion The results demonstrated the flow distribution patterns of the CoW under anatomical variations and clarified the collateral mechanism of the CoW. The flow ACoA is the most sensitive indexes to the morphology change of ipsilateral ICA. The relative independence of the circulation in anterior and posterior sections of the CoW is not broken and the function of ipsilateral PCoA is not activated until a severe stenosis of unilateral ICA occurs. PCoA is the most important collateral pathway of the collateral circulation and the missing of PCoA has the highest risk of stroke when the ipsilateral ICA has severe stenosis. These findings may provide the basis for future therapeutic and diagnosis applications. PMID:25603138

Netrin-1 rescues neuron loss by attenuating secondary apoptosis in ipsilateral thalamic nucleus following focal cerebral infarction in hypertensive rats.

PubMed

Liao, S-J; Gong, Q; Chen, X-R; Ye, L-X; Ding, Q; Zeng, J-S; Yu, J

2013-02-12

Neurological deficit following cerebral infarction correlates with not only primary injury, but also secondary neuronal apoptosis in remote loci connected to the infarction. Netrin-1 is crucial for axonal guidance by interacting with its receptors, deleted in colorectal cancer (DCC) and uncoordinated gene 5H (UNC5H). DCC and UNC5H are also dependence receptors inducing cell apoptosis when unbound by netrin-1. The present study is to investigate the role of netrin-1 and its receptors in ipsilateral ventroposterior thalamic nucleus (VPN) injury secondary to stroke in hypertensive rats. Renovascular hypertensive Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO). Continuous intracerebroventricular infusion of netrin-1 (600 ng/d for 7 days) or vehicle (IgG/Fc) was given 24h after MCAO. Neurological function was evaluated by postural reflex 8 and 14 days after MCAO. Then, immunoreactivity was determined in the ipsilateral VPN for NeuN, glial fibrillary acidic protein, netrin-1 and its receptors (DCC and UNC5H2), apoptosis was detected with Terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling (TUNEL) assay, and the expressions of caspase-3, netrin-1, DCC, and UNC5H2 were quantified by western blot analysis. MCAO resulted in the impaired postural reflex after 8 and 14 days, with decreased NeuN marked neurons and increased TUNEL-positive cells, as well as an up-regulation in the levels of cleaved caspase-3 and UNC5H2 protein in the ipsilateral VPN, without significant change in DCC or netrin-1 expression. By exogenous netrin-1 infusion, the number of neurons was increased in the ipsilateral VPN, and both TUNEL-positive cell number and caspase-3 protein level were reduced, while UNC5H2 expression remained unaffected, simultaneously, the impairment of postural reflex was improved. Taken together, the present study indicates that exogenous netrin-1 could rescue neuron loss by attenuating secondary apoptosis in the ipsilateral VPN after focal cerebral infarction, possibly via its receptor UNC5H2, suggesting that relative insufficiency of endogenous netrin-1 be an underlying mechanism of secondary injury in the VPN post stroke. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Driving with visual field loss : an exploratory simulation study

DOT National Transportation Integrated Search

2009-01-01

The goal of this study was to identify the influence of peripheral visual field loss (VFL) on driving performance in a motion-based driving simulator. Sixteen drivers (6 with VFL and 10 with normal visual fields) completed a 14 km simulated drive. Th...

[Relationship between visual field index and visual field morphological stages of glaucoma and their diagnostic value].

PubMed

Hou, X R; Qin, J Y; Ren, Z Q

2017-02-11

Objective: To investigate the rationality of visual field morphological stages of glaucoma, its relationship with visual field index and their diagnostic value. Methods: Retrospective series case study. Two hundred and seventy-four glaucoma patients and 100 normal control received visual field examination by Humphrey perimeter using standard automatic perimetry (SAP) program from March 2014 to September 2014. Glaucoma patients were graded into four stages according to characteristic morphological damage of visual field, distribution of mean defect (MD) and visual field index (VFI) of each stage were plotted and receiver operation characteristic curve (ROC) was used to explore its correlation with MD and VFI. The diagnostic value of MD and VFI was also compared. For the comparison of general data of subjects, categorical variables were compared using χ(2) test, numerical variables were compared using F test. MD and VFI were compared using ANOVA among stages according to visual field, followed by multiple comparisons using LSD method. The correlation between MD and VFI and different stages according to visual field defined their diagnostic value, and compared using area under the curve (AUC) of ROC. Results: No characteristic visual field damage was found in normal control group, and MD and VFI was (-0.06±1.24) dB and (99.15±0.76)%, respectively. Glaucomatous visual field damage was graded into early, medium, late and end stage according to morphological characteristic. MD for each stage were (-2.83±2.00) dB, (-9.70±3.68) dB, (-18.46±2.90) dB, and (-27.96±2.76) dB, respectively. VFI for each stage were (93.84±3.61)%, (75.16±10.85)%, (49.36±11.26)% and (17.65±10.59)%, respectively. MD and VFI of each stage of glaucomatous group and normal control group were all significantly different ( F= 1 165.53 and P <0.01 for MD; F= 1 028.04 and P <0.01 for VFI). AUC of ROC was A(MD)=0.91 and Se(MD)=0.01 (95% confident interval was 0.89-0.94) for MD, and A(VFI)=0.97, Se(VFI)=0.01 (95% confident interval was 0.94-0.10) for VFI. So, AUC(VFI)>AUC(MD) ( P< 0.05). Conclusions: It is feasible and rational of glaucomatous visual field damage to be graded into early, medium, late and end stage using Humphrey perimeter. Distribution of MD and VFI for each stage was relatively concentrative. Both MD and VFI were useful for grading glaucomatous visual field damage with preference for VFI. (Chin J Ophthalmol, 2017, 53: 92-97) .

Computer systems and methods for the query and visualization of multidimensional databases

DOEpatents

Stolte, Chris; Tang, Diane L.; Hanrahan, Patrick

2015-11-10

A computer displays a graphical user interface on its display. The graphical user interface includes a schema information region and a data visualization region. The schema information region includes a plurality of fields of a multi-dimensional database that includes at least one data hierarchy. The data visualization region includes a columns shelf and a rows shelf. The computer detects user actions to associate one or more first fields with the columns shelf and to associate one or more second fields with the rows shelf. The computer generates a visual table in the data visualization region in accordance with the user actions. The visual table includes one or more panes. Each pane has an x-axis defined based on data for the one or more first fields, and each pane has a y-axis defined based on data for the one or more second fields.

Innominate Vein Stenosis in Association with Ipsilateral Hyperdynamic Brachiobasilic Fistula Causing Ipsilateral Limb and Hemifacial Swelling.

PubMed

Narendra, J B; Sreenivas, J; Karthikeyan, V S; Nagaraja, N H

2017-01-01

A 34-year-old hypertensive woman with a hyperdynamic, left brachiobasilic dialysis fistula presented with a long history of throbbing in her head and swelling of the left side of the face. Tight stenosis of left brachiocephalic vein was found to be causing retrograde flow into the left jugular vein which normalized after dilatation and stenting with resolution of all the symptoms and patient is asymptomatic for 1 year.

Breast cancer in Poland syndrome.

PubMed

Havlik, R J; Sian, K U; Wagner, J D; Binford, R; Broadie, T A

1999-07-01

A 33-year-old African-American woman with a severe manifestation of Poland syndrome developed breast cancer in the ipsilateral breast. She had a severely hypoplastic upper extremity, including symbrachydactyly, and a hypoplastic forearm and upper arm. In addition, she lacked the sternal origin of the pectoralis muscle. She had a very small nipple-areola complex and no axillary hair. This is the first case report of breast cancer developing in the ipsilateral breast of a patient with Poland syndrome.

Increased expression of glutamic acid decarboxylase mRNA in rat substantia nigra after an ibotenic acid lesion in the caudate-putamen.

PubMed

Lindefors, N; Brené, S; Persson, H

1990-04-01

In situ hybridization histochemistry and RNA blots were used to study expression of glutamic acid decarboxylase (GAD) mRNA in rat caudate-nucleus and substantia nigra. In situ hybridization combined with computerized image analysis revealed that in the intact substantia nigra reticulata the cross-section area of GAD mRNA positive neurons were 25% larger in the dorsolateral part as compared with the ventromedial part. A unilateral ibotenic acid injection in caudate-putamen lesioned neurons, some of which project to the ipsilateral substantia nigra. An increased level of GAD mRNA was observed in substantia nigra ipsilateral to the lesion. Computerized image analysis of sections from in situ hybridization revealed an increase in the number of silver grains over GAD mRNA positive neurons in the dorsolateral substantia nigra reticulata ipsilateral to the lesion. However, no change was observed in the ventromedial part suggesting that GAD mRNA expression in this part of the nigra is less sensitive to inhibition by caudate-putamen afferents. In agreement with in situ experiments, RNA blots showed a 2-fold increased level of GAD mRNA in substantia nigra ipsilateral to the lesion. The increased GAD mRNA expression in the deafferented substantia nigra suggests a disinhibition of nigral GABA neurons, resulting in an increased utilization of GABA in these substantia nigra neurons.

Long-term use of cellular phones and brain tumours: increased risk associated with use for > or =10 years.

PubMed

Hardell, Lennart; Carlberg, Michael; Söderqvist, Fredrik; Mild, Kjell Hansson; Morgan, L Lloyd

2007-09-01

To evaluate brain tumour risk among long-term users of cellular telephones. Two cohort studies and 16 case-control studies on this topic were identified. Data were scrutinised for use of mobile phone for > or =10 years and ipsilateral exposure if presented. The cohort study was of limited value due to methodological shortcomings in the study. Of the 16 case-control studies, 11 gave results for > or =10 years' use or latency period. Most of these results were based on low numbers. An association with acoustic neuroma was found in four studies in the group with at least 10 years' use of a mobile phone. No risk was found in one study, but the tumour size was significantly larger among users. Six studies gave results for malignant brain tumours in that latency group. All gave increased odd ratios (OR), especially for ipsilateral exposure. In a meta-analysis, ipsilateral cell phone use for acoustic neuroma was OR = 2.4 (95% CI 1.1 to 5.3) and OR = 2.0, (1.2 to 3.4) for glioma using a tumour latency period of > or =10 years. Results from present studies on use of mobile phones for > or =10 years give a consistent pattern of increased risk for acoustic neuroma and glioma. The risk is highest for ipsilateral exposure.

Salivary glands abnormalities in oculo-auriculo-vertebral spectrum.

PubMed

Brotto, Davide; Manara, Renzo; Vio, Stefania; Ghiselli, Sara; Cantone, Elena; Mardari, Rodica; Toldo, Irene; Stritoni, Valentina; Castiglione, Alessandro; Lovo, Elisa; Trevisi, Patrizia; Bovo, Roberto; Martini, Alessandro

2018-01-01

Feeding and swallowing impairment are present in up to 80% of oculo-auriculo-vertebral spectrum (OAVS) patients. Salivary gland abnormalities have been reported in OAVS patients but their rate, features, and relationship with phenotype severity have yet to be defined. Parotid and submandibular salivary gland hypo/aplasia was evaluated on head MRI of 25 OAVS patients (16 with severe phenotype, Goldenhar syndrome) and 11 controls. All controls disclosed normal salivary glands. Abnormal parotid glands were found exclusively ipsilateral to facial microsomia in 21/25 OAVS patients (84%, aplasia in six patients) and showed no association with phenotype severity (14/16 patients with Goldenhar phenotype vs 7/9 patients with milder phenotype, p = 0.6). Submandibular salivary gland hypoplasia was detected in six OAVS patients, all with concomitant ipsilateral severe involvement of the parotid gland (p < 0.001). Submandibular salivary gland hypoplasia was associated to Goldenhar phenotype (p < 0.05). Parotid gland abnormalities were associated with ipsilateral fifth (p < 0.001) and seventh cranial nerve (p = 0.001) abnormalities. No association was found between parotid gland anomaly and ipsilateral internal carotid artery, inner ear, brain, eye, or spine abnormalities (p > 0.6). Salivary gland abnormalities are strikingly common in OAVS. Their detection might help the management of OAVS-associated swallowing and feeding impairment.

Predictors of Thyroid Gland Involvement in Hypopharyngeal Squamous Cell Carcinoma

PubMed Central

Chang, Jae Won; Koh, Yoon Woo; Chung, Woong Youn; Hong, Soon Won

2015-01-01

Purpose Decision to perform concurrent ipsilateral thyroidectomy on patients with hypopharyngeal cancer is important, and unnecessary thyroidectomy should be avoided if oncologically feasible. We hypothesized that concurrent ipsilateral thyroidectomy is not routinely required to prevent occult metastasis. This study aimed to determine the prevalence of histological thyroid invasion in patients with hypopharyngeal cancer, and to refine the indications for prophylactic ipsilateral thyroidectomy in patients with hypopharyngeal cancer. Materials and Methods A retrospective review of the medical records from the Department of Otolaryngology at Yonsei University College of Medicine was conducted from January 1994 to December 2009. A total of 49 patients underwent laryngopharyngectomy with thyroidectomy as a primary treatment of hypopharyngeal cancer. Results The incidence of thyroid gland involvement was 10.2%. The most common route of invasion was direct extension through the thyroid cartilage. Thyroid cartilage invasion (p=0.034) was the most significant factor associated with thyroid invasion. Disease-specific survival at 5 years was lower in patients with than without thyroid gland invasion (26.7% vs. 55.2%, respectively; p=0.032). Disease-free survival at 5 years was also lower in patients with than without thyroid gland invasion (20.0% vs. 52.1%, respectively; p=0.024). Conclusion Ipsilateral thyroidectomy in combination with total laryngopharyngectomy is indicated when invasion of the thyroid cartilage is suspected in patients with hypopharyngeal cancer. PMID:25837190

The effects of ipsilateral, contralateral, and bilateral broadband noise on the mid-level hump in intensity discriminationa)

PubMed Central

Roverud, Elin; Strickland, Elizabeth A.

2015-01-01

Previous psychoacoustical and physiological studies indicate that the medial olivocochlear reflex (MOCR), a bilateral, sound-evoked reflex, may lead to improved sound intensity discrimination in background noise. The MOCR can decrease the range of basilar-membrane compression and can counteract effects of neural adaptation from background noise. However, the contribution of these processes to intensity discrimination is not well understood. This study examined the effect of ipsilateral, contralateral, and bilateral noise on the “mid-level hump.” The mid-level hump refers to intensity discrimination Weber fractions (WFs) measured for short-duration, high-frequency tones which are poorer at mid levels than at lower or higher levels. The mid-level hump WFs may reflect a limitation due to basilar-membrane compression, and thus may be decreased by the MOCR. The noise was either short (50 ms) or long (150 ms), with the long noise intended to elicit the sluggish MOCR. For a tone in quiet, mid-level hump WFs improved with ipsilateral noise for most listeners, but not with contralateral noise. For a tone in ipsilateral noise, WFs improved with contralateral noise for most listeners, but only when both noises were long. These results are consistent with MOCR-induced WF improvements, possibly via decreases in effects of compression and neural adaptation. PMID:26627798

Abnormalities of hippocampal-cortical connectivity in temporal lobe epilepsy patients with hippocampal sclerosis

NASA Astrophysics Data System (ADS)

Li, Wenjing; He, Huiguang; Lu, Jingjing; Wang, Chunheng; Li, Meng; Lv, Bin; Jin, Zhengyu

2011-03-01

Hippocampal sclerosis (HS) is the most common damage seen in the patients with temporal lobe epilepsy (TLE). In the present study, the hippocampal-cortical connectivity was defined as the correlation between the hippocampal volume and cortical thickness at each vertex throughout the whole brain. We aimed to investigate the differences of ipsilateral hippocampal-cortical connectivity between the unilateral TLE-HS patients and the normal controls. In our study, the bilateral hippocampal volumes were first measured in each subject, and we found that the ipsilateral hippocampal volume significantly decreased in the left TLE-HS patients. Then, group analysis showed significant thinner average cortical thickness of the whole brain in the left TLE-HS patients compared with the normal controls. We found significantly increased ipsilateral hippocampal-cortical connectivity in the bilateral superior temporal gyrus, the right cingulate gyrus and the left parahippocampal gyrus of the left TLE-HS patients, which indicated structural vulnerability related to the hippocampus atrophy in the patient group. However, for the right TLE-HS patients, no significant differences were found between the patients and the normal controls, regardless of the ipsilateral hippocampal volume, the average cortical thickness or the patterns of hippocampal-cortical connectivity, which might be related to less atrophies observed in the MRI scans. Our study provided more evidence for the structural abnormalities in the unilateral TLE-HS patients.

Cerebrovascular risk factors for patients with cerebral watershed infarction: A case-control study based on computed tomography angiography in a population from Southwest China.

PubMed

Dong, Mei-Xue; Hu, Ling; Huang, Yuan-Jun; Xu, Xiao-Min; Liu, Yang; Wei, You-Dong

2017-07-01

To determine cerebrovascular risk factors for patients with cerebral watershed infarction (CWI) from Southwest China.Patients suffering from acute ischemic stroke were categorized into internal CWI (I-CWI), external CWI (E-CWI), or non-CWI (patients without CWI) groups. Clinical data were collected and degrees of steno-occlusion of all cerebral arteries were scored. Arteries associated with the circle of Willis were also assessed. Data were compared using Pearson chi-squared tests for categorical data and 1-way analysis of variance with Bonferroni post hoc tests for continuous data, as appropriate. Multivariate binary logistic regression analysis was performed to determine independent cerebrovascular risk factors for CWI.Compared with non-CWI, I-CWI had higher degrees of steno-occlusion of the ipsilateral middle cerebral artery, ipsilateral carotid artery, and contralateral middle cerebral artery. E-CWI showed no significant differences. All the 3 arteries were independent cerebrovascular risk factors for I-CWI confirmed by multivariate binary logistic regression analysis. I-CWI had higher degrees of steno-occlusion of the ipsilateral middle cerebral artery compared with E-CWI. No significant differences were found among arteries associated with the circle of Willis.The ipsilateral middle cerebral artery, carotid artery, and contralateral middle cerebral artery were independent cerebrovascular risk factors for I-CWI. No cerebrovascular risk factor was identified for E-CWI.

Potential involvement of μ-opioid receptor dysregulation on the reduced antinociception of morphine in the inflammatory pain state in mice.

PubMed

Aoki, Yuta; Mizoguchi, Hirokazu; Watanabe, Chizuko; Takeda, Kumiko; Sakurada, Tsukasa; Sakurada, Shinobu

2014-01-01

The antinociceptive effect of morphine in the inflammatory pain state was described in the von Frey filament test using the complete Freund's adjuvant (CFA)-induced mouse inflammatory pain model. After an i.pl. injection of CFA, mechanical allodynia was observed in the ipsilateral paw. The antinociceptive effect of morphine injected s.c. and i.t. against mechanical allodynia was reduced bilaterally at 1 day and 4 days after the CFA pretreatment. The expression level of mRNA for μ-opioid receptors at 1 day after the CFA pretreatment was reduced bilaterally in the lumbar spinal cord and dorsal root ganglion (DRG). In contrast, the protein level of μ-opioid receptors at 1 day after CFA pretreatment was decreased in the ipsilateral side in the DRG but not the lumbar spinal cord. Single or repeated i.t. pretreatment with the protein kinase Cα (PKCα) inhibitor Ro-32-0432 completely restored the reduced morphine antinociception in the contralateral paw but only partially restored it in the ipsilateral paw in the inflammatory pain state. In conclusion, reduced morphine antinociception against mechanical allodynia in the inflammatory pain state is mainly mediated via a decrease in μ-opioid receptors in the ipsilateral side and via the desensitization of μ-opioid receptors in the contralateral side by PKCα-induced phosphorylation.

Probing the Effects and Mechanisms of Electroacupuncture at Ipsilateral or Contralateral ST36-ST37 Acupoints on CFA-induced Inflammatory Pain.

PubMed

Lu, Kung-Wen; Hsu, Chao-Kuei; Hsieh, Ching-Liang; Yang, Jun; Lin, Yi-Wen

2016-02-24

Transient receptor potential vanilloid 1 (TRPV1) and associated signaling pathways have been reported to be increased in inflammatory pain signaling. There are accumulating evidences surrounding the therapeutic effect of electroacupuncture (EA). EA can reliably attenuate the increase of TRPV1 in mouse inflammatory pain models with unclear signaling mechanisms. Moreover, the difference in the clinical therapeutic effects between using the contralateral and ipsilateral acupoints has been rarely studied. We found that inflammatory pain, which was induced by injecting the complete Freund's adjuvant (CFA), (2.14 ± 0.1, p < 0.05, n = 8) can be alleviated after EA treatment at either ipsilateral (3.91 ± 0.21, p < 0.05, n = 8) or contralateral acupoints (3.79 ± 0.25, p < 0.05, n = 8). EA may also reduce nociceptive Nav sodium currents in dorsal root ganglion (DRG) neurons. The expression of TRPV1 and associated signaling pathways notably increased after the CFA injection; this expression can be further attenuated significantly in EA treatment. TRPV1 and associated signaling pathways can be prevented in TRPV1 knockout mice, suggesting that TRPV1 knockout mice are resistant to inflammatory pain. Through this study, we have increased the understanding of the mechanism that both ipsilateral and contralateral EA might alter TRPV1 and associated signaling pathways to reduce inflammatory pain.

Effect of muscle relaxation in the foot on simultaneous muscle contraction in the contralateral hand.

PubMed

Kato, Kouki; Kanosue, Kazuyuki

2016-10-28

We investigated the effects of foot muscle relaxation and contraction on muscle activities in the hand on both ipsilateral and contralateral sides. The subjects sat in an armchair with hands in the pronated position. They were able to freely move their right/left hand and foot. They performed three tasks for both ipsilateral (right hand and right foot) and contralateral limb coordination (left hand and right foot for a total of six tasks). These tasks involved: (1) wrist extension from a flexed (resting) position, (2) wrist extension with simultaneous ankle dorsiflexion from a plantarflexed (resting) position, and (3) wrist extension with simultaneous ankle relaxation from a dorsiflexed position. The subjects performed each task as fast as possible after hearing the start signal. Reaction time for the wrist extensor contraction (i.e. the degree to which it preceded the motor reaction time), as observed in electromyography (EMG), became longer when it was concurrently done with relaxation of the ankle dorsiflexor. Also, the magnitude of EMG activity became smaller, as compared with activity when wrist extensor contraction was done alone or with contraction of the ankle dorsiflexor. These effects were observed not only for the ipsilateral hand, but also for the contralateral hand. Our findings suggest that muscle relaxation in one limb interferes with muscle contraction in both the ipsilateral and contralateral limbs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The macaque midbrain reticular formation sends side-specific feedback to the superior colliculus.

PubMed

Wang, Niping; Warren, Susan; May, Paul J

2010-04-01

The central mesencephalic reticular formation (cMRF) likely plays a role in gaze control, as cMRF neurons receive tectal input and provide a bilateral projection back to the superior colliculus (SC). We examined the important question of whether this feedback is excitatory or inhibitory. Biotinylated dextran amine (BDA) was injected into the cMRF of M. fascicularis monkeys to anterogradely label reticulotectal terminals and retrogradely label tectoreticular neurons. BDA labeled profiles in the ipsi- and contralateral intermediate gray layer (SGI) were examined electron microscopically. Postembedding GABA immunochemistry was used to identify putative inhibitory profiles. Nearly all (94.7%) of the ipsilateral BDA labeled terminals were GABA positive, but profiles postsynaptic to these labeled terminals were exclusively GABA negative. In addition, BDA labeled terminals were observed to contact BDA labeled dendrites, indicating the presence of a monosynaptic feedback loop connecting the cMRF and ipsilateral SC. In contrast, within the contralateral SGI, half of the BDA labeled terminals were GABA positive, while more than a third were GABA negative. All the postsynaptic profiles were GABA negative. These results indicate the cMRF provides inhibitory feedback to the ipsilateral side of the SC, but it has more complex effects on the contralateral side. The ipsilateral projection may help tune the "winner-take-all" mechanism that produces a unified saccade signal, while the contralateral projections may contribute to the coordination of activity between the two colliculi.

Visual Receptive Field Heterogeneity and Functional Connectivity of Adjacent Neurons in Primate Frontoparietal Association Cortices.

PubMed

Viswanathan, Pooja; Nieder, Andreas

2017-09-13

The basic organization principles of the primary visual cortex (V1) are commonly assumed to also hold in the association cortex such that neurons within a cortical column share functional connectivity patterns and represent the same region of the visual field. We mapped the visual receptive fields (RFs) of neurons recorded at the same electrode in the ventral intraparietal area (VIP) and the lateral prefrontal cortex (PFC) of rhesus monkeys. We report that the spatial characteristics of visual RFs between adjacent neurons differed considerably, with increasing heterogeneity from VIP to PFC. In addition to RF incongruences, we found differential functional connectivity between putative inhibitory interneurons and pyramidal cells in PFC and VIP. These findings suggest that local RF topography vanishes with hierarchical distance from visual cortical input and argue for increasingly modified functional microcircuits in noncanonical association cortices that contrast V1. SIGNIFICANCE STATEMENT Our visual field is thought to be represented faithfully by the early visual brain areas; all the information from a certain region of the visual field is conveyed to neurons situated close together within a functionally defined cortical column. We examined this principle in the association areas, PFC, and ventral intraparietal area of rhesus monkeys and found that adjacent neurons represent markedly different areas of the visual field. This is the first demonstration of such noncanonical organization of these brain areas. Copyright © 2017 the authors 0270-6474/17/378919-10$15.00/0.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berres, Anne Sabine

This slide presentation describes basic topological concepts, including topological spaces, homeomorphisms, homotopy, betti numbers. Scalar field topology explores finding topological features and scalar field visualization, and vector field topology explores finding topological features and vector field visualization.

Hearing after congenital deafness: central auditory plasticity and sensory deprivation.

PubMed

Kral, A; Hartmann, R; Tillein, J; Heid, S; Klinke, R

2002-08-01

The congenitally deaf cat suffers from a degeneration of the inner ear. The organ of Corti bears no hair cells, yet the auditory afferents are preserved. Since these animals have no auditory experience, they were used as a model for congenital deafness. Kittens were equipped with a cochlear implant at different ages and electro-stimulated over a period of 2.0-5.5 months using a monopolar single-channel compressed analogue stimulation strategy (VIENNA-type signal processor). Following a period of auditory experience, we investigated cortical field potentials in response to electrical biphasic pulses applied by means of the cochlear implant. In comparison to naive unstimulated deaf cats and normal hearing cats, the chronically stimulated animals showed larger cortical regions producing middle-latency responses at or above 300 microV amplitude at the contralateral as well as the ipsilateral auditory cortex. The cortex ipsilateral to the chronically stimulated ear did not show any signs of reduced responsiveness when stimulating the 'untrained' ear through a second cochlear implant inserted in the final experiment. With comparable duration of auditory training, the activated cortical area was substantially smaller if implantation had been performed at an older age of 5-6 months. The data emphasize that young sensory systems in cats have a higher capacity for plasticity than older ones and that there is a sensitive period for the cat's auditory system.

Changes in dopamine transporter expression in the midbrain following traumatic brain injury: an immunohistochemical and in situ hybridization study in a mouse model.

PubMed

Shimada, Ryo; Abe, Keiichi; Furutani, Rui; Kibayashi, Kazuhiko

2014-03-01

An association has been suggested between trauma and neurological degenerative diseases. Magnetic resonance imaging has revealed that traumatic brain injury (TBI) can cause primary lesions in the midbrain including the substantia nigra (SN). Dopamine transporter (DAT) is mainly expressed in the SN, ventral tegmental area (VTA), and retrorubral field (RRF) of the ventral midbrain. Previous western blot studies have examined DAT levels in the rat frontal cortex and striatum after a controlled cortical impact (CCI); however, no study has comprehensively examined DAT expression in the midbrain following TBI in an animal model. We used immunohistochemistry and in situ hybridization to examine the time-dependent changes in the expression of DAT in the midbrain during the first 14 days after TBI in a mouse CCI model. The expression of DAT protein in the RRF on the side ipsilateral to the site of injury decreased in 14 days after injury. Dopamine transporter mRNA expression in the RRF on the ipsilateral side decreased in 1, 7, and 14 days and increased in 4 days after injury. These findings indicated that TBI induced changes in DAT expression in the RRF. Because the DAT pumps dopamine (DA) out of the synapse back into the cytosol and maintains DA homeostasis, the decreased expression of DAT after TBI may result in decreased DA neurotransmission in the brain.

View-Dependent Streamline Deformation and Exploration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tong, Xin; Edwards, John; Chen, Chun-Ming

Occlusion presents a major challenge in visualizing 3D flow and tensor fields using streamlines. Displaying too many streamlines creates a dense visualization filled with occluded structures, but displaying too few streams risks losing important features. We propose a new streamline exploration approach by visually manipulating the cluttered streamlines by pulling visible layers apart and revealing the hidden structures underneath. This paper presents a customized view-dependent deformation algorithm and an interactive visualization tool to minimize visual cluttering for visualizing 3D vector and tensor fields. The algorithm is able to maintain the overall integrity of the fields and expose previously hidden structures.more » Our system supports both mouse and direct-touch interactions to manipulate the viewing perspectives and visualize the streamlines in depth. By using a lens metaphor of different shapes to select the transition zone of the targeted area interactively, the users can move their focus and examine the vector or tensor field freely.« less

Vision problems

MedlinePlus

... shade or curtain hanging across part of your visual field. Optic neuritis : inflammation of the optic nerve ... to ask your doctor Images Crossed eyes Eye Visual acuity test Slit-lamp exam Visual field test ...

The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex.

PubMed

Bajo, Victoria M; Leach, Nicholas D; Cordery, Patricia M; Nodal, Fernando R; King, Andrew J

2014-09-01

Cholinergic inputs to the auditory cortex can modulate sensory processing and regulate stimulus-specific plasticity according to the behavioural state of the subject. In order to understand how acetylcholine achieves this, it is essential to elucidate the circuitry by which cholinergic inputs influence the cortex. In this study, we described the distribution of cholinergic neurons in the basal forebrain and their inputs to the auditory cortex of the ferret, a species used increasingly in studies of auditory learning and plasticity. Cholinergic neurons in the basal forebrain, visualized by choline acetyltransferase and p75 neurotrophin receptor immunocytochemistry, were distributed through the medial septum, diagonal band of Broca, and nucleus basalis magnocellularis. Epipial tracer deposits and injections of the immunotoxin ME20.4-SAP (monoclonal antibody specific for the p75 neurotrophin receptor conjugated to saporin) in the auditory cortex showed that cholinergic inputs originate almost exclusively in the ipsilateral nucleus basalis. Moreover, tracer injections in the nucleus basalis revealed a pattern of labelled fibres and terminal fields that resembled acetylcholinesterase fibre staining in the auditory cortex, with the heaviest labelling in layers II/III and in the infragranular layers. Labelled fibres with small en-passant varicosities and simple terminal swellings were observed throughout all auditory cortical regions. The widespread distribution of cholinergic inputs from the nucleus basalis to both primary and higher level areas of the auditory cortex suggests that acetylcholine is likely to be involved in modulating many aspects of auditory processing. © 2014 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

21 CFR 886.1360 - Visual field laser instrument.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Visual field laser instrument. 886.1360 Section 886.1360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1360 Visual field laser instrument...

Dioptric defocus maps across the visual field for different indoor environments.

PubMed

García, Miguel García; Ohlendorf, Arne; Schaeffel, Frank; Wahl, Siegfried

2018-01-01

One of the factors proposed to regulate the eye growth is the error signal derived from the defocus in the retina and actually, this might arise from defocus not only in the fovea but the whole visual field. Therefore, myopia could be better predicted by spatio-temporally mapping the 'environmental defocus' over the visual field. At present, no devices are available that could provide this information. A 'Kinect sensor v1' camera (Microsoft Corp.) and a portable eye tracker were used for developing a system for quantifying 'indoor defocus error signals' across the central 58° of the visual field. Dioptric differences relative to the fovea (assumed to be in focus) were recorded over the visual field and 'defocus maps' were generated for various scenes and tasks.

Word learning and the cerebral hemispheres: from serial to parallel processing of written words

PubMed Central

Ellis, Andrew W.; Ferreira, Roberto; Cathles-Hagan, Polly; Holt, Kathryn; Jarvis, Lisa; Barca, Laura

2009-01-01

Reading familiar words differs from reading unfamiliar non-words in two ways. First, word reading is faster and more accurate than reading of unfamiliar non-words. Second, effects of letter length are reduced for words, particularly when they are presented in the right visual field in familiar formats. Two experiments are reported in which right-handed participants read aloud non-words presented briefly in their left and right visual fields before and after training on those items. The non-words were interleaved with familiar words in the naming tests. Before training, naming was slow and error prone, with marked effects of length in both visual fields. After training, fewer errors were made, naming was faster, and the effect of length was much reduced in the right visual field compared with the left. We propose that word learning creates orthographic word forms in the mid-fusiform gyrus of the left cerebral hemisphere. Those word forms allow words to access their phonological and semantic representations on a lexical basis. But orthographic word forms also interact with more posterior letter recognition systems in the middle/inferior occipital gyri, inducing more parallel processing of right visual field words than is possible for any left visual field stimulus, or for unfamiliar non-words presented in the right visual field. PMID:19933140

Normal Threshold Size of Stimuli in Children Using a Game-Based Visual Field Test.

PubMed

Wang, Yanfang; Ali, Zaria; Subramani, Siddharth; Biswas, Susmito; Fenerty, Cecilia; Henson, David B; Aslam, Tariq

2017-06-01

The aim of this study was to demonstrate and explore the ability of novel game-based perimetry to establish normal visual field thresholds in children. One hundred and eighteen children (aged 8.0 ± 2.8 years old) with no history of visual field loss or significant medical history were recruited. Each child had one eye tested using a game-based visual field test 'Caspar's Castle' at four retinal locations 12.7° (N = 118) from fixation. Thresholds were established repeatedly using up/down staircase algorithms with stimuli of varying diameter (luminance 20 cd/m 2 , duration 200 ms, background luminance 10 cd/m 2 ). Relationships between threshold and age were determined along with measures of intra- and intersubject variability. The Game-based visual field test was able to establish threshold estimates in the full range of children tested. Threshold size reduced with increasing age in children. Intrasubject variability and intersubject variability were inversely related to age in children. Normal visual field thresholds were established for specific locations in children using a novel game-based visual field test. These could be used as a foundation for developing a game-based perimetry screening test for children.

Intraoperative Subcortical Electrical Mapping of the Optic Tract in Awake Surgery Using a Virtual Reality Headset.

PubMed

Mazerand, Edouard; Le Renard, Marc; Hue, Sophie; Lemée, Jean-Michel; Klinger, Evelyne; Menei, Philippe

2017-01-01

Brain mapping during awake craniotomy is a well-known technique to preserve neurological functions, especially the language. It is still challenging to map the optic radiations due to the difficulty to test the visual field intraoperatively. To assess the visual field during awake craniotomy, we developed the Functions' Explorer based on a virtual reality headset (FEX-VRH). The impaired visual field of 10 patients was tested with automated perimetry (the gold standard examination) and the FEX-VRH. The proof-of-concept test was done during the surgery performed on a patient who was blind in his right eye and presenting with a left parietotemporal glioblastoma. The FEX-VRH was used intraoperatively, simultaneously with direct subcortical electrostimulation, allowing identification and preservation of the optic radiations. The FEX-VRH detected 9 of the 10 visual field defects found by automated perimetry. The patient who underwent an awake craniotomy with intraoperative mapping of the optic tract using the FEX-VRH had no permanent postoperative visual field defect. Intraoperative visual field assessment with the FEX-VRH during direct subcortical electrostimulation is a promising approach to mapping the optical radiations and preventing a permanent visual field defect during awake surgery for epilepsy or tumor. Copyright © 2016 Elsevier Inc. All rights reserved.

Hyperpolarized (3)He magnetic resonance imaging: comparison with four-dimensional x-ray computed tomography imaging in lung cancer.

PubMed

Mathew, Lindsay; Wheatley, Andrew; Castillo, Richard; Castillo, Edward; Rodrigues, George; Guerrero, Thomas; Parraga, Grace

2012-12-01

Pulmonary functional imaging using four-dimensional x-ray computed tomographic (4DCT) imaging and hyperpolarized (3)He magnetic resonance imaging (MRI) provides regional lung function estimates in patients with lung cancer in whom pulmonary function measurements are typically dominated by tumor burden. The aim of this study was to evaluate the quantitative spatial relationship between 4DCT and hyperpolarized (3)He MRI ventilation maps. Eleven patients with lung cancer provided written informed consent to 4DCT imaging and MRI performed within 11 ± 14 days. Hyperpolarized (3)He MRI was acquired in breath-hold after inhalation from functional residual capacity of 1 L hyperpolarized (3)He, whereas 4DCT imaging was acquired over a single tidal breath of room air. For hyperpolarized (3)He MRI, the percentage ventilated volume was generated using semiautomated segmentation; for 4DCT imaging, pulmonary function maps were generated using the correspondence between identical tissue elements at inspiratory and expiratory phases to generate percentage ventilated volume. After accounting for differences in image acquisition lung volumes ((3)He MRI: 1.9 ± 0.5 L ipsilateral, 2.3 ± 0.7 L contralateral; 4DCT imaging: 1.2 ± 0.3 L ipsilateral, 1.3 ± 0.4 L contralateral), there was no significant difference in percentage ventilated volume between hyperpolarized (3)He MRI (72 ± 11% ipsilateral, 79 ± 12% contralateral) and 4DCT imaging (74 ± 3% ipsilateral, 75 ± 4% contralateral). Spatial correspondence between 4DCT and (3)He MRI ventilation was evaluated using the Dice similarity coefficient index (ipsilateral, 86 ± 12%; contralateral, 88 ± 12%). Despite rather large differences in image acquisition breathing maneuvers, good spatial and significant quantitative agreement was observed for ventilation maps on hyperpolarized (3)He MRI and 4DCT imaging, suggesting that pulmonary regions with good lung function are similar between modalities in this small group of patients with lung cancer. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

Importance of anatomical dominance in the evaluation of coronary dilatation in Kawasaki disease.

PubMed

Dionne, Audrey; Hanna, Baher; Trinh Tan, Frédérick; Desjardins, Laurent; Lapierre, Chantale; Déry, Julie; Fournier, Anne; Dahdah, Nagib

2017-07-01

Introduction In Kawasaki disease, although coronary dilatation is attributed to vasculitis, the effect of myocardial inflammation is underestimated. Coronary dilatations are determined by Z-scores, which do not take into account dominance. The aim of the present study was to describe the impact of coronary dominance on dilatation in Kawasaki disease. We performed a retrospective analysis of coronary dilatations according to angiography categorisation of dominance. Of 28 patients (2.6 [0.2-10.1] years), right dominance was present in 15 patients and left in 13. Early dilatation was present in all patients, of whom 11 were ipsilateral to the dominant segment and 17 contralateral. Ipsilateral dilatations were present at diagnosis (9/11 versus 6/17, p=0.02) compared with contralateral dilatations, which developed 2 weeks after diagnosis (9/11 versus 16/17, p=0.29). Coronary artery Z-scores of patients with contralateral dilatation increased at 2 weeks, before returning to baseline values (2.0±2.2 at diagnosis, 4.1±1.8 at 2 weeks, 1.8±1.2 at 3-6 months, p=0.001), compared with patients with ipsilateral dilatation in whom Z-scores were maximal at diagnosis and remained stable (3.0±0.9, 2.7±1.1 and 2.6±1.5, respectively, p=0.13). Dominant coronary artery Z-scores were higher compared with non-dominant segments at diagnosis (3.0±0.9 versus 1.0±0.8, p<0.001) and at late follow-up (2.6±1.5 versus 0.4±1.4, p=0.002) in patients with ipsilateral dilatation. Progression of coronary dilatation after diagnosis may be a sign of dilatation secondary to vasculitis, as opposed to regression of Z-scores in ipsilateral dilatations, probably related to physiological vasodilatation in response to carditis. This needs to be validated in larger studies against vasculitic and myocardial inflammatory markers.

Does the Dumbbell-Carrying Position Change the Muscle Activity in Split Squats and Walking Lunges?

PubMed Central

Lehnert, Michal; Zaatar, Amr M.Z.; Svoboda, Zdenek; Xaverova, Zuzana

2015-01-01

Abstract Stastny, P, Lehnert, M, Zaatar, AMZ, Svoboda, Z, and Xaverova, Z. Does the dumbbell-carrying position change the muscle activity in split squats and walking lunges? J Strength Cond Res 29(11): 3177–3187, 2015—The forward walking lunge (WL) and split squat (SSq) are similar exercises that have differences in the eccentric phase, and both can be performed in the ipsilateral or contralateral carrying conditions. This study aimed to determine the effects of dumbbell-carrying position on the kinematics and electromyographic (EMG) amplitudes of the gluteus medius (Gmed), vastus medialis (VM), vastus lateralis (VL), and biceps femoris during WLs and SSqs. The resistance-trained (RT) and the non–resistance-trained (NT) groups (both n = 14) performed ipsilateral WLs, contralateral WLs, ipsilateral SSqs, and contralateral SSqs in a randomized order in a simulated training session. The EMG amplitude, expressed as a percentage of the maximal voluntary isometric contraction (%MVIC), and the kinematics, expressed as the range of motion (ROM) of the hip and knee, were measured during 5 repetition maximum for both legs. The repeated measure analyses of variance showed significant differences between the RT and NT groups. The NT group showed a smaller knee flexion ROM (p < 0.001, η2 = 0.36) during both types of WLs, whereas the RT group showed a higher eccentric Gmed amplitude (p < 0.001, η2 = 0.46) during all exercises and a higher eccentric VL amplitude (p < 0.001, η2 = 0.63) during contralateral WLs. Further differences were found between contralateral and ipsilateral WLs in both the RT (p < 0.001, η2 = 0.69) and NT groups (p < 0.001, η2 = 0.80), and contralateral WLs resulted in higher eccentric Gmed amplitudes. Contralateral WLs highly activated the Gmed (90% MVIC); therefore, this exercise can increase the Gmed maximal strength. The ipsilateral loading condition did not increase the Gmed or VM activity in the RT or NT group. PMID:25968228

SU-E-J-87: Ventilation Weighting Effect On Mean Doses of Both Side Lungs for Patients with Advanced Stage Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, H; Xia, P; Yu, N

Purpose: To study ventilation weighting effect on radiation doses to both side lungs for patients with advanced stage lung cancer. Methods: Fourteen patients with advanced stage lung cancer were included in this retrospective study. Proprietary software was developed to calculate the lung ventilation map based on 4DCT images acquired for radiation therapy. Two phases of inhale (0%) and exhale (50%) were used for the lung ventilation calculations. For each patient, the CT images were resampled to the same dose calculation resolution of 3mmx3mmx3mm. The ventilation distribution was then normalized by the mean value of the ventilation. The ventilation weighted dosemore » was calculated by applying linearly weighted ventilation to the dose of each pixel. The lung contours were automatically delineated from patient CT image with lung window, excluding the tumor and high density tissues. For contralateral and ipsilateral lungs, the mean lung doses from the original plan and ventilation weighted mean lung doses were compared using two tail t-Test. Results: The average of mean dose was 6.1 ±3.8Gy for the contralateral lungs, and 26.2 ± 14.0Gy for the ipsilateral lungs. The average of ventilation weighted dose was 6.3± 3.8Gy for the contralateral lungs and 24.6 ± 13.1Gy for the ipsilateral lungs. The statistics analysis shows the significance of the mean dose increase (p<0.015) for the contralateral lungs and decrease (p<0.005) for the ipsilateral lungs. Conclusion: Ventilation weighted doses were greater than the un-weighted doses for contralateral lungs and smaller for ipsilateral lungs. This Result may be helpful to understand the radiation dosimetric effect on the lung function and provide planning guidance for patients with advance stage lung cancer.« less

Electromyography findings of the cricopharyngeus in association with ipsilateral pharyngeal and laryngeal muscles.

PubMed

Halum, Stacey L; Shemirani, Nima L; Merati, Albert L; Jaradeh, Safwan; Toohill, Robert J

2006-04-01

We reviewed a large series of cricopharyngeal (CP) muscle electromyography (EMG) results and compared them with the EMG results from the inferior constrictor (IC), thyroarytenoid, (TA), cricothyroid (CT), and posterior cricoarytenoid (PCA) muscles. We performed a retrospective review of all CP muscle EMG reports from studies performed between January 1996 and June 2003. All of the tested elements from the CP muscle EMG reports were recorded. The EMG results were recorded for the ipsilateral IC, TA, CT, and PCA muscles if they were simultaneously tested. Each muscle result was classified as normal, neurogenic inactive axonal injury (IAI), or neurogenic active axonal injury (AAI), and the muscle findings were compared. A patient chart review was performed to determine a clinical correlation. Fifty-nine patients underwent CP muscle EMG. Eighteen patients had bilateral EMG studies, making a total of 77 CP muscle studies. Nineteen sets of CP muscle results were normal, 43 demonstrated neurogenic IAI, and 15 demonstrated neurogenic AAI. The ipsilateral IC and CP muscles had the same innervation status in 27 of 28 studies (p < .0001). When the ipsilateral TA muscle was studied simultaneously with the CP muscle, 31 of 50 studies had the same innervation status (p = .005). The ipsilateral CT and CP muscles demonstrated the same innervation status in 40 of 50 studies (p < .0001). The correlations between the CP and IC muscle findings and between the CP and CT muscle findings were both stronger than the correlation between the CP and TA muscle findings (p < .0001 and p = .024, respectively). The chart review demonstrated the clinical findings to be consistent with the EMG results. The EMG studies demonstrated that CP muscle findings have the strongest correlation with IC muscle findings, followed by the CT and TA muscles. This outcome does not support theories indicating that the recurrent laryngeal nerve innervates the CP muscle in all cases.

Ipsilateral irradiation for well lateralized carcinomas of the oral cavity and oropharynx: results on tumor control and xerostomia

PubMed Central

Cerezo, Laura; Martín, Margarita; López, Mario; Marín, Alicia; Gómez, Alberto

2009-01-01

Background In head and neck cancer, bilateral neck irradiation is the standard approach for many tumor locations and stages. Increasing knowledge on the pattern of nodal invasion leads to more precise targeting and normal tissue sparing. The aim of the present study was to evaluate the morbidity and tumor control for patients with well lateralized squamous cell carcinomas of the oral cavity and oropharynx treated with ipsilateral radiotherapy. Methods Twenty consecutive patients with lateralized carcinomas of the oral cavity and oropharynx were treated with a prospective management approach using ipsilateral irradiation between 2000 and 2007. This included 8 radical oropharyngeal and 12 postoperative oral cavity carcinomas, with Stage T1-T2, N0-N2b disease. The actuarial freedom from contralateral nodal recurrence was determined. Late xerostomia was evaluated using the European Organization for Research and Treatment of Cancer QLQ-H&N35 questionnaire and the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 3. Results At a median follow-up of 58 months, five-year overall survival and loco-regional control rates were 82.5% and 100%, respectively. No local or contralateral nodal recurrences were observed. Mean dose to the contralateral parotid gland was 4.72 Gy and to the contralateral submandibular gland was 15.30 Gy. Mean score for dry mouth was 28.1 on the 0-100 QLQ-H&N35 scale. According to CTCAE v3 scale, 87.5% of patients had grade 0-1 and 12.5% grade 2 subjective xerostomia. The unstimulated salivary flow was > 0.2 ml/min in 81.2% of patients and 0.1-0.2 ml/min in 19%. None of the patients showed grade 3 xerostomia. Conclusion In selected patients with early and moderate stages, well lateralized oral and oropharyngeal carcinomas, ipsilateral irradiation treatment of the primary site and ipsilateral neck spares salivary gland function without compromising loco-regional control. PMID:19723329

Tablets at the bedside - iPad-based visual field test used in the diagnosis of Intrasellar Haemangiopericytoma: a case report.

PubMed

Nesaratnam, Nisha; Thomas, Peter B M; Kirollos, Ramez; Vingrys, Algis J; Kong, George Y X; Martin, Keith R

2017-04-24

In the assessment of a pituitary mass, objective visual field testing represents a valuable means of evaluating mass effect, and thus in deciding whether surgical management is warranted. In this vignette, we describe a 73 year-old lady who presented with a three-week history of frontal headache, and 'blurriness' in the left side of her vision, due to a WHO grade III anaplastic haemangiopericytoma compressing the optic chiasm. We report how timely investigations, including an iPad-based visual field test (Melbourne Rapid Field, (MRF)) conducted at the bedside aided swift and appropriate management of the patient. We envisage such a test having a role in assessing bed-bound patients in hospital where access to formal visual field testing is difficult, or indeed in rapid testing of visual fields at the bedside to screen for post-operative complications, such as haematoma.

Stimulation of the substantia nigra influences the specification of memory-guided saccades

PubMed Central

Mahamed, Safraaz; Garrison, Tiffany J.; Shires, Joel

2013-01-01

In the absence of sensory information, we rely on past experience or memories to guide our actions. Because previous experimental and clinical reports implicate basal ganglia nuclei in the generation of movement in the absence of sensory stimuli, we ask here whether one output nucleus of the basal ganglia, the substantia nigra pars reticulata (nigra), influences the specification of an eye movement in the absence of sensory information to guide the movement. We manipulated the level of activity of neurons in the nigra by introducing electrical stimulation to the nigra at different time intervals while monkeys made saccades to different locations in two conditions: one in which the target location remained visible and a second in which the target location appeared only briefly, requiring information stored in memory to specify the movement. Electrical manipulation of the nigra occurring during the delay period of the task, when information about the target was maintained in memory, altered the direction and the occurrence of subsequent saccades. Stimulation during other intervals of the memory task or during the delay period of the visually guided saccade task had less effect on eye movements. On stimulated trials, and only when the visual stimulus was absent, monkeys occasionally (∼20% of the time) failed to make saccades. When monkeys made saccades in the absence of a visual stimulus, stimulation of the nigra resulted in a rotation of the endpoints ipsilaterally (∼2°) and increased the reaction time of contralaterally directed saccades. When the visual stimulus was present, stimulation of the nigra resulted in no significant rotation and decreased the reaction time of contralaterally directed saccades slightly. Based on these measurements, stimulation during the delay period of the memory-guided saccade task influenced the metrics of saccades much more than did stimulation during the same period of the visually guided saccade task. Because these effects occurred with manipulation of nigral activity well before the initiation of saccades and in trials in which the visual stimulus was absent, we conclude that information from the basal ganglia influences the specification of an action as it is evolving primarily during performance of memory-guided saccades. When visual information is available to guide the specification of the saccade, as occurs during visually guided saccades, basal ganglia information is less influential. PMID:24259551

Cortical and Subcortical Coordination of Visual Spatial Attention Revealed by Simultaneous EEG-fMRI Recording.

PubMed

Green, Jessica J; Boehler, Carsten N; Roberts, Kenneth C; Chen, Ling-Chia; Krebs, Ruth M; Song, Allen W; Woldorff, Marty G

2017-08-16

Visual spatial attention has been studied in humans with both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) individually. However, due to the intrinsic limitations of each of these methods used alone, our understanding of the systems-level mechanisms underlying attentional control remains limited. Here, we examined trial-to-trial covariations of concurrently recorded EEG and fMRI in a cued visual spatial attention task in humans, which allowed delineation of both the generators and modulators of the cue-triggered event-related oscillatory brain activity underlying attentional control function. The fMRI activity in visual cortical regions contralateral to the cued direction of attention covaried positively with occipital gamma-band EEG, consistent with activation of cortical regions representing attended locations in space. In contrast, fMRI activity in ipsilateral visual cortical regions covaried inversely with occipital alpha-band oscillations, consistent with attention-related suppression of the irrelevant hemispace. Moreover, the pulvinar nucleus of the thalamus covaried with both of these spatially specific, attention-related, oscillatory EEG modulations. Because the pulvinar's neuroanatomical geometry makes it unlikely to be a direct generator of the scalp-recorded EEG, these covariational patterns appear to reflect the pulvinar's role as a regulatory control structure, sending spatially specific signals to modulate visual cortex excitability proactively. Together, these combined EEG/fMRI results illuminate the dynamically interacting cortical and subcortical processes underlying spatial attention, providing important insight not realizable using either method alone. SIGNIFICANCE STATEMENT Noninvasive recordings of changes in the brain's blood flow using functional magnetic resonance imaging and electrical activity using electroencephalography in humans have individually shown that shifting attention to a location in space produces spatially specific changes in visual cortex activity in anticipation of a stimulus. The mechanisms controlling these attention-related modulations of sensory cortex, however, are poorly understood. Here, we recorded these two complementary measures of brain activity simultaneously and examined their trial-to-trial covariations to gain insight into these attentional control mechanisms. This multi-methodological approach revealed the attention-related coordination of visual cortex modulation by the subcortical pulvinar nucleus of the thalamus while also disentangling the mechanisms underlying the attentional enhancement of relevant stimulus input and those underlying the concurrent suppression of irrelevant input. Copyright © 2017 the authors 0270-6474/17/377803-08$15.00/0.

Temporal visual field defects are associated with monocular inattention in chiasmal pathology.

PubMed

Fledelius, Hans C

2009-11-01

Chiasmal lesions have been shown to give rise occasionally to uni-ocular temporal inattention, which cannot be compensated for by volitional eye movement. This article describes the assessments of 46 such patients with chiasmal pathology. It aims to determine the clinical spectrum of this disorder, including interference with reading. Retrospective consecutive observational clinical case study over a 7-year period comprising 46 patients with chiasmal field loss of varying degrees. Observation of reading behaviour during monocular visual acuity testing ascertained from consecutive patients who appeared unable to read optotypes on the temporal side of the chart. Visual fields were evaluated by kinetic (Goldmann) and static (Octopus) techniques. Five patients who clearly manifested this condition are presented in more detail. The results of visual field testing were related to absence or presence of uni-ocular visual inattentive behaviour for distance visual acuity testing and/or reading printed text. Despite normal eye movements, the 46 patients making up the clinical series perceived only optotypes in the nasal part of the chart, in one eye or in both, when tested for each eye in turn. The temporal optotypes were ignored, and this behaviour persisted despite instruction to search for any additional letters temporal to those, which had been seen. This phenomenon of unilateral visual inattention held for both eyes in 18 and was unilateral in the remaining 28 patients. Partial or full reversibility after treatment was recorded in 21 of the 39 for whom reliable follow-up data were available. Reading a text was affected in 24 individuals, and permanently so in six. A neglect-like spatial unawareness and a lack of cognitive compensation for varying degrees of temporal visual field loss were present in all the patients observed. Not only is visual field loss a feature of chiasmal pathology, but the higher visual function of affording attention within the temporal visual field by means of using conscious thought to invoke appropriate compensatory eye movement was also absent. This suggests the possibility of 'trans-synaptic dysfunction' caused by loss of visual input to higher visual centres. When inattention to the temporal side is manifest on monocular visual testing it should raise the suspicion of chiasmal pathology.

Visual discrimination training improves Humphrey perimetry in chronic cortically induced blindness.

PubMed

Cavanaugh, Matthew R; Huxlin, Krystel R

2017-05-09

To assess if visual discrimination training improves performance on visual perimetry tests in chronic stroke patients with visual cortex involvement. 24-2 and 10-2 Humphrey visual fields were analyzed for 17 chronic cortically blind stroke patients prior to and following visual discrimination training, as well as in 5 untrained, cortically blind controls. Trained patients practiced direction discrimination, orientation discrimination, or both, at nonoverlapping, blind field locations. All pretraining and posttraining discrimination performance and Humphrey fields were collected with online eye tracking, ensuring gaze-contingent stimulus presentation. Trained patients recovered ∼108 degrees 2 of vision on average, while untrained patients spontaneously improved over an area of ∼16 degrees 2 . Improvement was not affected by patient age, time since lesion, size of initial deficit, or training type, but was proportional to the amount of training performed. Untrained patients counterbalanced their improvements with worsening of sensitivity over ∼9 degrees 2 of their visual field. Worsening was minimal in trained patients. Finally, although discrimination performance improved at all trained locations, changes in Humphrey sensitivity occurred both within trained regions and beyond, extending over a larger area along the blind field border. In adults with chronic cortical visual impairment, the blind field border appears to have enhanced plastic potential, which can be recruited by gaze-controlled visual discrimination training to expand the visible field. Our findings underscore a critical need for future studies to measure the effects of vision restoration approaches on perimetry in larger cohorts of patients. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

The nervus terminalis in larval and adult Xenopus laevis.

PubMed

Hofmann, M H; Meyer, D L

1989-09-25

Nervus terminalis (nt) projections were studied by HRP injections into one nostril in adult Xenopus and in Xenopus tadpoles. Central nt targets are: medial septum, preoptic nucleus, nucleus of the anterior commissure, and hypothalamus (mainly ipsilaterally). In Xenopus tadpoles, additional fibers reach the ipsilateral dorsal thalamus and the mesencephalic tegmentum, bilaterally; furthermore, hypothalamic projections are bilateral. Xenopus tadpole nt connections resemble those of adult urodeles more closely than the projections of frogs. However, Xenopus tadpoles lack nt innervation of the medial septum.

The Effect of Diazoxide Upon Heat Shock Protein and Physiological Response to Hemorrhagic Shock and Cerebral Stroke

DTIC Science & Technology

2006-06-16

ischemic kidney model [121]. Photothrombic brain injury elicits the expression of HSP70 and HSP27 . HSP70 expression as early as one hour post-trauma...delineated the area of necrosis at 24 hours post-thrombic injury in ipsilateral cortex. HSP27 expression also was found to be upregulated and in fact...more globally expressed in the entire ipsilateral cerebral cortex, primarily in astrocytes [122]. 25 HSP25 and HSP27 Research demonstrates

Localized tension pneumothorax: unrecognized form of barotrauma in adult respiratory distress syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gobien, R.P.; Reines, H.D.; Schabel, S.I.

1982-01-01

Loculated tension pneumothorax, usually localized in an inferior subpulmonic or paracardiac location, is a frequent complication of respiratory therapy in adult respiratory distress syndrome (ARDS), and may occur in spite of a functioning ipsilateral chest tube. The only radiographic evidence of tension may be slight flattening of the cardiac border and ipsilateral contour change or depression of the diaphragm. Severe cardiovascular and pulmonary compromise may result from a small volume of pleura air under tension, and rapid recognition and drainage are required.

Innervation of the human cricopharyngeal muscle by the recurrent laryngeal nerve and external branch of the superior laryngeal nerve.

PubMed

Uludag, Mehmet; Aygun, Nurcihan; Isgor, Adnan

2017-06-01

The major component of the upper esophageal sphincter is the cricopharyngeal muscle (CPM). We assessed the contribution of the laryngeal nerves to motor innervation of the CPM. We performed an intraoperative electromyographic study of 27 patients. The recurrent laryngeal nerve (RLN), vagus nerve, external branch of the superior laryngeal nerve (EBSLN), and pharyngeal plexus (PP) were stimulated. Responses were evaluated by visual observation of CPM contractions and electromyographic examination via insertion of needle electrodes into the CPM. In total, 46 CPMs (24 right, 22 left) were evaluated. PP stimulation produced both positive visual contractions and electromyographic (EMG) responses in 42 CPMs (2080 ± 1583 μV). EBSLN stimulation produced visual contractions of 28 CPMs and positive EMG responses in 35 CPMs (686 ± 630 μV). Stimulation of 45 RLNs produced visible contractions of 37 CPMs and positive EMG activity in 41 CPMs (337 ± 280 μV). Stimulation of 42 vagal nerves resulted in visible contractions of 36 CPMs and positive EMG responses in 37 CPMs (292 ± 229 μV). Motor activity was noted in 32 CPMs by both RLN and EBSLN stimulation, 9 CPMs by RLN stimulation, and 3 CPMs by EBSLN stimulation; 2 CPMs exhibited no response. This is the first study to show that the EBSLN contributes to motor innervation of the human CPM. The RLN, EBSLN, or both of the nerves innervate the 90, 75, and 70 % of the CPMs ipsilaterally, respectively.

Complex motor task associated with non-linear BOLD responses in cerebro-cortical areas and cerebellum.

PubMed

Alahmadi, Adnan A S; Samson, Rebecca S; Gasston, David; Pardini, Matteo; Friston, Karl J; D'Angelo, Egidio; Toosy, Ahmed T; Wheeler-Kingshott, Claudia A M

2016-06-01

Previous studies have used fMRI to address the relationship between grip force (GF) applied to an object and BOLD response. However, whilst the majority of these studies showed a linear relationship between GF and neural activity in the contralateral M1 and ipsilateral cerebellum, animal studies have suggested the presence of non-linear components in the GF-neural activity relationship. Here, we present a methodology for assessing non-linearities in the BOLD response to different GF levels, within primary motor as well as sensory and cognitive areas and the cerebellum. To be sensitive to complex forms, we designed a feasible grip task with five GF targets using an event-related visually guided paradigm and studied a cohort of 13 healthy volunteers. Polynomial functions of increasing order were fitted to the data. (1) activated motor areas irrespective of GF; (2) positive higher-order responses in and outside M1, involving premotor, sensory and visual areas and cerebellum; (3) negative correlations with GF, predominantly involving the visual domain. Overall, our results suggest that there are physiologically consistent behaviour patterns in cerebral and cerebellar cortices; for example, we observed the presence of a second-order effect in sensorimotor areas, consistent with an optimum metabolic response at intermediate GF levels, while higher-order behaviour was found in associative and cognitive areas. At higher GF levels, sensory-related cortical areas showed reduced activation, interpretable as a redistribution of the neural activity for more demanding tasks. These results have the potential of opening new avenues for investigating pathological mechanisms of neurological diseases.

Vestibular responses in the macaque pedunculopontine nucleus and central mesencephalic reticular formation.

PubMed

Aravamuthan, B R; Angelaki, D E

2012-10-25

The pedunculopontine nucleus (PPN) and central mesencephalic reticular formation (cMRF) both send projections and receive input from areas with known vestibular responses. Noting their connections with the basal ganglia, the locomotor disturbances that occur following lesions of the PPN or cMRF, and the encouraging results of PPN deep brain stimulation in Parkinson's disease patients, both the PPN and cMRF have been linked to motor control. In order to determine the existence of and characterize vestibular responses in the PPN and cMRF, we recorded single neurons from both structures during vertical and horizontal rotation, translation, and visual pursuit stimuli. The majority of PPN cells (72.5%) were vestibular-only (VO) cells that responded exclusively to rotation and translation stimuli but not visual pursuit. Visual pursuit responses were much more prevalent in the cMRF (57.1%) though close to half of cMRF cells were VO cells (41.1%). Directional preferences also differed between the PPN, which was preferentially modulated during nose-down pitch, and cMRF, which was preferentially modulated during ipsilateral yaw rotation. Finally, amplitude responses were similar between the PPN and cMRF during rotation and pursuit stimuli, but PPN responses to translation were of higher amplitude than cMRF responses. Taken together with their connections to the vestibular circuit, these results implicate the PPN and cMRF in the processing of vestibular stimuli and suggest important roles for both in responding to motion perturbations like falls and turns. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Abnormal tuning of saccade-related cells in pontine reticular formation of strabismic monkeys.

PubMed

Walton, Mark M G; Mustari, Michael J

2015-08-01

Strabismus is a common disorder, characterized by a chronic misalignment of the eyes and numerous visual and oculomotor abnormalities. For example, saccades are often highly disconjugate. For humans with pattern strabismus, the horizontal and vertical disconjugacies vary with eye position. In monkeys, manipulations that disturb binocular vision during the first several weeks of life result in a chronic strabismus with characteristics that closely match those in human patients. Early onset strabismus is associated with altered binocular sensitivity of neurons in visual cortex. Here we test the hypothesis that brain stem circuits specific to saccadic eye movements are abnormal. We targeted the pontine paramedian reticular formation, a structure that directly projects to the ipsilateral abducens nucleus. In normal animals, neurons in this structure are characterized by a high-frequency burst of spikes associated with ipsiversive saccades. We recorded single-unit activity from 84 neurons from four monkeys (two normal, one exotrope, and one esotrope), while they made saccades to a visual target on a tangent screen. All 24 neurons recorded from the normal animals had preferred directions within 30° of pure horizontal. For the strabismic animals, the distribution of preferred directions was normal on one side of the brain, but highly variable on the other. In fact, 12/60 neurons recorded from the strabismic animals preferred vertical saccades. Many also had unusually weak or strong bursts. These data suggest that the loss of corresponding binocular vision during infancy impairs the development of normal tuning characteristics for saccade-related neurons in brain stem. Copyright © 2015 the American Physiological Society.

Central corneal thickness and progression of the visual field and optic disc in glaucoma

PubMed Central

Chauhan, B C; Hutchison, D M; LeBlanc, R P; Artes, P H; Nicolela, M T

2005-01-01

Aims: To determine whether central corneal thickness (CCT) is a significant predictor of visual field and optic disc progression in open angle glaucoma. Methods: Data were obtained from a prospective study of glaucoma patients tested with static automated perimetry and confocal scanning laser tomography every 6 months. Progression was determined using a trend based approach called evidence of change (EOC) analysis in which sectoral ordinal scores based on the significance of regression coefficients of visual field pattern deviation and neuroretinal rim area over time are summed. Visual field progression was also determined using the event based glaucoma change probability (GCP) analysis using both total and pattern deviation. Results: The sample contained 101 eyes of 54 patients (mean (SD) age 56.5 (9.8) years) with a mean follow up of 9.2 (0.7) years and 20.7 (2.3) sets of examinations every 6 months. Lower CCT was associated with worse baseline visual fields and lower mean IOP in the follow up. In the longitudinal analysis CCT was not correlated with the EOC scores for visual field or optic disc change. In the GCP analyses, there was a tendency for groups classified as progressing to have lower CCT compared to non-progressing groups. In a multivariate analyses accounting for IOP, the opposite was found, whereby higher CCT was associated with visual field progression. None of the independent factors were predictive of optic disc progression. Conclusions: In this cohort of patients with established glaucoma, CCT was not a useful index in the risk assessment of visual field and optic disc progression. PMID:16024855

Detection of Visual Field Loss in Pituitary Disease: Peripheral Kinetic Versus Central Static

PubMed Central

Rowe, Fiona J.; Cheyne, Christopher P.; García-Fiñana, Marta; Noonan, Carmel P.; Howard, Claire; Smith, Jayne; Adeoye, Joanne

2015-01-01

Abstract Visual field assessment is an important clinical evaluation for eye disease and neurological injury. We evaluated Octopus semi-automated kinetic peripheral perimetry (SKP) and Humphrey static automated central perimetry for detection of neurological visual field loss in patients with pituitary disease. We carried out a prospective cross-sectional diagnostic accuracy study comparing Humphrey central 30-2 SITA threshold programme with a screening protocol for SKP on Octopus perimetry. Humphrey 24-2 data were extracted from 30-2 results. Results were independently graded for presence/absence of field defect plus severity of defect. Fifty patients (100 eyes) were recruited (25 males and 25 females), with mean age of 52.4 years (SD = 15.7). Order of perimeter assessment (Humphrey/Octopus first) and order of eye tested (right/left first) were randomised. The 30-2 programme detected visual field loss in 85%, the 24-2 programme in 80%, and the Octopus combined kinetic/static strategy in 100% of eyes. Peripheral visual field loss was missed by central threshold assessment. Qualitative comparison of type of visual field defect demonstrated a match between Humphrey and Octopus results in 58%, with a match for severity of defect in 50%. Tests duration was 9.34 minutes (SD = 2.02) for Humphrey 30-2 versus 10.79 minutes (SD = 4.06) for Octopus perimetry. Octopus semi-automated kinetic perimetry was found to be superior to central static testing for detection of pituitary disease-related visual field loss. Where reliant on Humphrey central static perimetry, the 30-2 programme is recommended over the 24-2 programme. Where kinetic perimetry is available, this is preferable to central static programmes for increased detection of peripheral visual field loss. PMID:27928344

Cosmography and Data Visualization

NASA Astrophysics Data System (ADS)

Pomarède, Daniel; Courtois, Hélène M.; Hoffman, Yehuda; Tully, R. Brent

2017-05-01

Cosmography, the study and making of maps of the universe or cosmos, is a field where visual representation benefits from modern three-dimensional visualization techniques and media. At the extragalactic distance scales, visualization is contributing to our understanding of the complex structure of the local universe in terms of spatial distribution and flows of galaxies and dark matter. In this paper, we report advances in the field of extragalactic cosmography obtained using the SDvision visualization software in the context of the Cosmicflows Project. Here, multiple visualization techniques are applied to a variety of data products: catalogs of galaxy positions and galaxy peculiar velocities, reconstructed velocity field, density field, gravitational potential field, velocity shear tensor viewed in terms of its eigenvalues and eigenvectors, envelope surfaces enclosing basins of attraction. These visualizations, implemented as high-resolution images, videos, and interactive viewers, have contributed to a number of studies: the cosmography of the local part of the universe, the nature of the Great Attractor, the discovery of the boundaries of our home supercluster of galaxies Laniakea, the mapping of the cosmic web, and the study of attractors and repellers.

Interventions for visual field defects in patients with stroke.

PubMed

Pollock, Alex; Hazelton, Christine; Henderson, Clair A; Angilley, Jayne; Dhillon, Baljean; Langhorne, Peter; Livingstone, Katrina; Munro, Frank A; Orr, Heather; Rowe, Fiona J; Shahani, Uma

2011-10-05

Visual field defects are estimated to affect 20% to 57% of people who have had a stroke. Visual field defects can affect functional ability in activities of daily living (commonly affecting mobility, reading and driving), quality of life, ability to participate in rehabilitation, and depression, anxiety and social isolation following stroke. There are many interventions for visual field defects, which are proposed to work by restoring the visual field (restitution); compensating for the visual field defect by changing behaviour or activity (compensation); substituting for the visual field defect by using a device or extraneous modification (substitution); or ensuring appropriate diagnosis, referral and treatment prescription through standardised assessment or screening, or both. To determine the effects of interventions for people with visual field defects after stroke. We searched the Cochrane Stroke Group Trials Register (February 2011), the Cochrane Eyes and Vision Group Trials Register (December 2009) and nine electronic bibliographic databases including CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (1950 to December 2009), EMBASE (1980 to December 2009), CINAHL (1982 to December 2009), AMED (1985 to December 2009), and PsycINFO (1967 to December 2009). We also searched reference lists and trials registers, handsearched journals and conference proceedings and contacted experts. Randomised trials in adults after stroke, where the intervention was specifically targeted at improving the visual field defect or improving the ability of the participant to cope with the visual field loss. The primary outcome was functional ability in activities of daily living and secondary outcomes included functional ability in extended activities of daily living, reading ability, visual field measures, balance, falls, depression and anxiety, discharge destination or residence after stroke, quality of life and social isolation, visual scanning, adverse events and death. Two review authors independently screened abstracts, extracted data and appraised trials. We undertook an assessment of methodological quality for allocation concealment, blinding of outcome assessors, method of dealing with missing data, and other potential sources of bias. Thirteen studies (344 randomised participants, 285 of whom were participants with stroke) met the inclusion criteria for this review. However, only six of these studies compared the effect of an intervention with a placebo, control or no treatment group and were included in comparisons within this review. Four studies compared the effect of scanning (compensatory) training with a control or placebo intervention. Meta-analysis demonstrated that scanning training is more effective than control or placebo at improving reading ability (three studies, 129 participants; mean difference (MD) 3.24, 95% confidence interval (CI) 0.84 to 5.59) and visual scanning (three studies, 129 participants; MD 18.84, 95% CI 12.01 to 25.66) but that scanning may not improve visual field outcomes (two studies, 110 participants; MD -0.70, 95% CI -2.28 to 0.88). There were insufficient data to enable generalised conclusions to be made about the effectiveness of scanning training relative to control or placebo for the primary outcome of activities of daily living (one study, 33 participants). Only one study (19 participants) compared the effect of a restitutive intervention with a control or placebo intervention and only one study (39 participants) compared the effect of a substitutive intervention with a control or placebo intervention. There is limited evidence which supports the use of compensatory scanning training for patients with visual field defects (and possibly co-existing visual neglect) to improve scanning and reading outcomes. There is insufficient evidence to reach a conclusion about the impact of compensatory scanning training on functional activities of daily living. There is insufficient evidence to reach generalised conclusions about the benefits of visual restitution training (VRT) (restitutive intervention) or prisms (substitutive intervention) for patients with visual field defects after stroke.

Multidimensional structured data visualization method and apparatus, text visualization method and apparatus, method and apparatus for visualizing and graphically navigating the world wide web, method and apparatus for visualizing hierarchies

DOEpatents

Risch, John S [Kennewick, WA; Dowson, Scott T [West Richland, WA; Hart, Michelle L [Richland, WA; Hatley, Wes L [Kennewick, WA

2008-05-13

A method of displaying correlations among information objects comprises receiving a query against a database; obtaining a query result set; and generating a visualization representing the components of the result set, the visualization including one of a plane and line to represent a data field, nodes representing data values, and links showing correlations among fields and values. Other visualization methods and apparatus are disclosed.

Multidimensional structured data visualization method and apparatus, text visualization method and apparatus, method and apparatus for visualizing and graphically navigating the world wide web, method and apparatus for visualizing hierarchies

DOEpatents

Risch, John S [Kennewick, WA; Dowson, Scott T [West Richland, WA

2012-03-06

A method of displaying correlations among information objects includes receiving a query against a database; obtaining a query result set; and generating a visualization representing the components of the result set, the visualization including one of a plane and line to represent a data field, nodes representing data values, and links showing correlations among fields and values. Other visualization methods and apparatus are disclosed.

Active Learning in Neuroscience: A Manipulative to Simulate Visual Field Defects

ERIC Educational Resources Information Center

Li, Andrew Yue-Lin; Carvalho, Helena

2016-01-01

Prevalent in 20-57% of stroke patients, visual field defects have been shown to impact quality of life. Studies have shown increased risk of falling, ambulatory difficulties, impaired reading ability, and feelings of panic in crowded or unfamiliar places in patients with visual field defects. Rehabilitation, independence, and mental health may…

Unboxing the Black Box of Visual Expertise in Medicine

ERIC Educational Resources Information Center

Jarodzka, Halszka; Boshuizen, Henny P. .

2017-01-01

Visual expertise in medicine has been a subject of research since many decades. Interestingly, it has been investigated from two little related fields, namely the field that focused mainly on the visual search aspects whilst ignoring higher-level cognitive processes involved in medical expertise, and the field that mainly focused on these…

Visual Field Asymmetry in Attentional Capture

ERIC Educational Resources Information Center

Du, Feng; Abrams, Richard A.

2010-01-01

The present study examined the spatial distribution of involuntary attentional capture over the two visual hemi-fields. A new experiment, and an analysis of three previous experiments showed that distractors in the left visual field that matched a sought-for target in color produced a much larger capture effect than identical distractors in the…

Vision, touch and object manipulation in Senegal parrots Poicephalus senegalus

PubMed Central

Demery, Zoe P.; Chappell, Jackie; Martin, Graham R.

2011-01-01

Parrots are exceptional among birds for their high levels of exploratory behaviour and manipulatory abilities. It has been argued that foraging method is the prime determinant of a bird's visual field configuration. However, here we argue that the topography of visual fields in parrots is related to their playful dexterity, unique anatomy and particularly the tactile information that is gained through their bill tip organ during object manipulation. We measured the visual fields of Senegal parrots Poicephalus senegalus using the ophthalmoscopic reflex technique and also report some preliminary observations on the bill tip organ in this species. We found that the visual fields of Senegal parrots are unlike those described hitherto in any other bird species, with both a relatively broad frontal binocular field and a near comprehensive field of view around the head. The behavioural implications are discussed and we consider how extractive foraging and object exploration, mediated in part by tactile cues from the bill, has led to the absence of visual coverage of the region below the bill in favour of more comprehensive visual coverage above the head. PMID:21525059

Dioptric defocus maps across the visual field for different indoor environments

PubMed Central

García, Miguel García; Ohlendorf, Arne; Schaeffel, Frank; Wahl, Siegfried

2017-01-01

One of the factors proposed to regulate the eye growth is the error signal derived from the defocus in the retina and actually, this might arise from defocus not only in the fovea but the whole visual field. Therefore, myopia could be better predicted by spatio-temporally mapping the ‘environmental defocus’ over the visual field. At present, no devices are available that could provide this information. A ‘Kinect sensor v1’ camera (Microsoft Corp.) and a portable eye tracker were used for developing a system for quantifying ‘indoor defocus error signals’ across the central 58° of the visual field. Dioptric differences relative to the fovea (assumed to be in focus) were recorded over the visual field and ‘defocus maps’ were generated for various scenes and tasks. PMID:29359108

Advanced pigment dispersion glaucoma secondary to phakic intraocular collamer lens implant.

PubMed

Ye, Clara; Patel, Cajal K; Momont, Anna C; Liu, Yao

2018-06-01

We report a case of pigment dispersion glaucoma secondary to uncomplicated phakic intraocular collamer lens (ICL) (Visian ICL™, Staar Inc., Monrovia, CA) implant that resulted in advanced visual field loss. A 50-year-old man presented for routine follow-up status post bilateral phakic intraocular collamer lens (ICL) placement 8 years earlier. He was incidentally found to have a decline in visual acuity from an anterior subcapsular cataract and elevated intraocular pressure (IOP) in the left eye. There were signs of pigment dispersion and no evidence of angle closure. Diffuse optic nerve thinning was consistent with advanced glaucomatous visual field defects. Pigment dispersion was also present in the patient's right eye, but without elevated IOP or visual field defects. The patient was treated with topical glaucoma medications and the phakic ICL in the left eye was removed concurrently with cataract surgery to prevent further visual field loss. Pigment dispersion glaucoma is a serious adverse outcome after phakic ICL implantation and regular post-operative monitoring may prevent advanced visual field loss.

Torsional ARC Effectively Expands the Visual Field in Hemianopia

PubMed Central

Satgunam, PremNandhini; Peli, Eli

2012-01-01

Purpose Exotropia in congenital homonymous hemianopia has been reported to provide field expansion that is more useful when accompanied with harmonios anomalous retinal correspondence (HARC). Torsional strabismus with HARC provides a similar functional advantage. In a subject with hemianopia demonstrating a field expansion consistent with torsion we documented torsional strabismus and torsional HARC. Methods Monocular visual fields under binocular fixation conditions were plotted using a custom dichoptic visual field perimeter (DVF). The DVF was also modified to measure perceived visual directions under dissociated and associated conditions across the central 50° diameter field. The field expansion and retinal correspondence of a subject with torsional strabismus (along with exotropia and right hypertropia) with congenital homonymous hemianopia was compared to that of another exotropic subject with acquired homonymous hemianopia without torsion and to a control subject with minimal phoria. Torsional rotations of the eyes were calculated from fundus photographs and perimetry. Results Torsional ARC documented in the subject with congenital homonymous hemianopia provided a functional binocular field expansion up to 18°. Normal retinal correspondence was mapped for the full 50° visual field in the control subject and for the seeing field of the acquired homonymous hemianopia subject, limiting the functional field expansion benefit. Conclusions Torsional strabismus with ARC, when occurring with homonymous hemianopia provides useful field expansion in the lower and upper fields. Dichoptic perimetry permits documentation of ocular alignment (lateral, vertical and torsional) and perceived visual direction under binocular and monocular viewing conditions. Evaluating patients with congenital or early strabismus for HARC is useful when considering surgical correction, particularly in the presence of congenital homonymous hemianopia. PMID:22885782

Anisotropies in the perceived spatial displacement of motion-defined contours: opposite biases in the upper-left and lower-right visual quadrants.

PubMed

Fan, Zhao; Harris, John

2010-10-12

In a recent study (Fan, Z., & Harris, J. (2008). Perceived spatial displacement of motion-defined contours in peripheral vision. Vision Research, 48(28), 2793-2804), we demonstrated that virtual contours defined by two regions of dots moving in opposite directions were displaced perceptually in the direction of motion of the dots in the more eccentric region when the contours were viewed in the right visual field. Here, we show that the magnitude and/or direction of these displacements varies in different quadrants of the visual field. When contours were presented in the lower visual field, the direction of perceived contour displacement was consistent with that when both contours were presented in the right visual field. However, this illusory motion-induced spatial displacement disappeared when both contours were presented in the upper visual field. Also, perceived contour displacement in the direction of the more eccentric dots was larger in the right than in the left visual field, perhaps because of a hemispheric asymmetry in attentional allocation. Quadrant-based analyses suggest that the pattern of results arises from opposite directions of perceived contour displacement in the upper-left and lower-right visual quadrants, which depend on the relative strengths of two effects: a greater sensitivity to centripetal motion, and an asymmetry in the allocation of spatial attention. Copyright © 2010 Elsevier Ltd. All rights reserved.

Preoperative Duplex Scanning is a Helpful Diagnostic Tool in Neurogenic Thoracic Outlet Syndrome.

PubMed

Orlando, Megan S; Likes, Kendall C; Mirza, Serene; Cao, Yue; Cohen, Anne; Lum, Ying Wei; Freischlag, Julie A

2016-01-01

To evaluate the diagnostic role of venous and arterial duplex scanning in neurogenic thoracic outlet syndrome (NTOS). Retrospective review of patients who underwent duplex ultrasonography prior to first rib resection and scalenectomy (FRRS) for NTOS from 2005 to 2013. Abnormal scans included ipsilateral compression (IC) with abduction of the symptomatic extremity (>50% change in subclavian vessel flow), contralateral (asymptomatic side) compression (CC) or bilateral compression (BC). A total of 143 patients (76% female, average age 34, range 13-59) underwent bilateral preoperative duplex scanning. Ipsilateral compression was seen in 44 (31%), CC in 12 (8%), and BC in 14 (10%). Seventy-three (51%) patients demonstrated no compression. Patients with IC more often experienced intraoperative pneumothoraces (49% vs. 25%, P < .05) and had positive Adson tests (86% vs. 61%, P < .02). Compression of the subclavian vein or artery on duplex ultrasonography can assist in NTOS diagnosis. Ipsilateral compression on abduction often correlates with Adson testing. © The Author(s) 2016.

Subareolar Sclerosing Ductal Hyperplasia.

PubMed

Cheng, Esther; D'Alfonso, Timothy M; Arafah, Maria; Marrero Rolon, Rebecca; Ginter, Paula S; Hoda, Syed A

2017-02-01

Subareolar sclerosing duct hyperplasia (SSDH) remains to be fully characterized nearly 20 years after initial description. Thirty-five SSDH cases diagnosed over a 16-year period (January 2000 to December 2015) were reviewed. All patients were female (mean age = 59 years, range = 18-80) who had presented with a unilateral solitary lesion (left 22, right 13) with a mean size of 1.3 cm (range = 0.4-3.0 cm), and showed florid and papillary epithelial hyperplasia with dense sclerosis without involvement of nipple or areolar epidermis. Significant lesions concurrent within SSDH included low-grade adenosquamous carcinoma (n = 1), ductal carcinoma in situ (DCIS; n = 1), lobular carcinoma in situ (LCIS; n = 1), and atypical ductal hyperplasia (ADH; n = 13). No case of SSDH recurred in a mean follow-up of 44 months (range = 6-189). Subsequent significant lesions occurred in 6 patients: DCIS (n = 3; ipsilateral 2, contralateral 1), ipsilateral ADH (n = 2), and ipsilateral atypical lobular hyperplasia (n = 1). Long-term follow-up for patients with SSDH is indicated as DCIS can occur subsequently in either breast.

Influence of Isokinetic Strength Training of Unilateral Ankle on Ipsilateral One-legged Standing Balance of Adults

PubMed Central

Son, Sung Min; Kang, Kyung Woo; Lee, Na Kyung; Nam, Seok Hyun; Kwon, Jung Won; Kim, Kyoung

2013-01-01

[Purpose] The purpose of the current study was to investigate the changes in one-legged standing balance of the ipsilateral lower limb following unilateral isokinetic strength training. [Subjects and Methods] Thirty healthy adult volunteers were randomly assigned to either a training group or a control group, so that each group included 15 subjects. Subjects in the training group performed unilateral ankle isokinetic exercises of the dominant leg using the Biodex 3 PRO System for a period of four weeks. Ipsilateral one-legged standing balance was evaluated before and after the intervention with three stability indexes of balance using the Biodex System: Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), and Overall Stability Index (OSI). [Results] Comparison of pre- and post-test data revealed significant improvements in strength values (dorsiflexion, plantarflexion, eversion, and inversion) and stability indexes (APSI, MLSI, OSI). [Conclusion] These results suggest that ankle strengthening exercise can be considered as a form of exercise that may assist individuals with improvement of balance. PMID:24259783

Distinct Corticostriatal and Intracortical Pathways Mediate Bilateral Sensory Responses in the Striatum.

PubMed

Reig, Ramon; Silberberg, Gilad

2016-12-01

Individual striatal neurons integrate somatosensory information from both sides of the body, however, the afferent pathways mediating these bilateral responses are unclear. Whereas ipsilateral corticostriatal projections are prevalent throughout the neocortex, contralateral projections provide sparse input from primary sensory cortices, in contrast to the dense innervation from motor and frontal regions. There is, therefore, an apparent discrepancy between the observed anatomical pathways and the recorded striatal responses. We used simultaneous in vivo whole-cell and extracellular recordings combined with focal cortical silencing, to dissect the afferent pathways underlying bilateral sensory integration in the mouse striatum. We show that unlike direct corticostriatal projections mediating responses to contralateral whisker deflection, responses to ipsilateral stimuli are mediated mainly by intracortical projections from the contralateral somatosensory cortex (S1). The dominant pathway is the callosal projection from contralateral to ipsilateral S1. Our results suggest a functional difference between the cortico-basal ganglia pathways underlying bilateral sensory and motor processes. © The Author 2016. Published by Oxford University Press.

Physical activity and neural correlates of aging: A combined TMS/fMRI study

PubMed Central

McGregor, Keith M.; Zlatar, Zvinka; Kleim, Erin; Sudhyadhom, Atchar; Bauer, Andrew; Phan, Stephanie; Seeds, Lauren; Ford, Anastasia; Manini, Todd M.; White, Keith D.; Kleim, Jeffrey; Crosson, Bruce

2013-01-01

Aerobic exercise has been suggested to ameliorate aging-related decline in humans. Recently, evidence has indicated chronological aging is associated with decreases in measures of interhemispheric inhibition during unimanual movements, but that such decreases may be mitigated by long-term physical fitness. The present study investigated measures of ipsilateral (right) primary motor cortex activity during right-hand movements using functional magnetic resonance imaging and transcranial magnetic stimulation (TMS). Healthy, right-handed participant groups were comprised of 12 sedentary older adults, 12 physically active older adults, and 12 young adults. Active older adults and younger adults evidenced longer ipsilateral silent periods (iSP) and less positive BOLD of ipsilateral motor cortex (iM1) as compared to sedentary older adults. Across groups, duration of iSP from TMS was inversely correlated with BOLD activity in iM1 during unimanual movement. These findings suggest that increased physical activity may have a role in decreasing aging-related losses of interhemispheric inhibition. PMID:21440574

Large Field Visualization with Demand-Driven Calculation

NASA Technical Reports Server (NTRS)

Moran, Patrick J.; Henze, Chris

1999-01-01

We present a system designed for the interactive definition and visualization of fields derived from large data sets: the Demand-Driven Visualizer (DDV). The system allows the user to write arbitrary expressions to define new fields, and then apply a variety of visualization techniques to the result. Expressions can include differential operators and numerous other built-in functions, ail of which are evaluated at specific field locations completely on demand. The payoff of following a demand-driven design philosophy throughout becomes particularly evident when working with large time-series data, where the costs of eager evaluation alternatives can be prohibitive.

Role of inter-hemispheric transfer in generating visual evoked potentials in V1-damaged brain hemispheres

PubMed Central

Kavcic, Voyko; Triplett, Regina L.; Das, Anasuya; Martin, Tim; Huxlin, Krystel R.

2015-01-01

Partial cortical blindness is a visual deficit caused by unilateral damage to the primary visual cortex, a condition previously considered beyond hopes of rehabilitation. However, recent data demonstrate that patients may recover both simple and global motion discrimination following intensive training in their blind field. The present experiments characterized motion-induced neural activity of cortically blind (CB) subjects prior to the onset of visual rehabilitation. This was done to provide information about visual processing capabilities available to mediate training-induced visual improvements. Visual Evoked Potentials (VEPs) were recorded from two experimental groups consisting of 9 CB subjects and 9 age-matched, visually-intact controls. VEPs were collected following lateralized stimulus presentation to each of the 4 visual field quadrants. VEP waveforms were examined for both stimulus-onset (SO) and motion-onset (MO) related components in postero-lateral electrodes. While stimulus presentation to intact regions of the visual field elicited normal SO-P1, SO-N1, SO-P2 and MO-N2 amplitudes and latencies in contralateral brain regions of CB subjects, these components were not observed contralateral to stimulus presentation in blind quadrants of the visual field. In damaged brain hemispheres, SO-VEPs were only recorded following stimulus presentation to intact visual field quadrants, via inter-hemispheric transfer. MO-VEPs were only recorded from damaged left brain hemispheres, possibly reflecting a native left/right asymmetry in inter-hemispheric connections. The present findings suggest that damaged brain hemispheres contain areas capable of responding to visual stimulation. However, in the absence of training or rehabilitation, these areas only generate detectable VEPs in response to stimulation of the intact hemifield of vision. PMID:25575450

Visual impairment, visual functioning, and quality of life assessments in patients with glaucoma.

PubMed Central

Parrish, R K

1996-01-01

BACKGROUND/PURPOSE: To determine the relation between visual impairment, visual functioning, and the global quality of life in patients with glaucoma. METHODS: Visual impairment, defined with the American Medical Association Guides to the Evaluation of Permanent Impairment; visual functioning, measured with the VF-14 and the Field Test Version of the National Eye Institute-Visual Functioning Questionnaire (NEI-VFQ); and the global quality of life, assessed with the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), were determined in 147 consecutive patients with glaucoma. RESULTS: None of the SF-36 domains demonstrated more than a weak correlation with visual impairment. The VF-14 scores were moderately correlated with visual impairment. Of the twelve NEI-VFQ scales, distance activities and vision specific dependency were moderately correlated with visual impairment. Of the twelve NEI-VFQ scales, distance activities and vision specific dependency were moderately correlated with visual field impairment; vision specific social functioning, near activities, vision specific role difficulties, general vision, vision specific mental health, color vision, and driving were modestly correlated; visual pain was weakly correlated; and two were not significantly correlated. Correcting for visual actuity weakened the strength of the correlation coefficients. CONCLUSIONS: The SF-36 is unlikely to be useful in determining visual impairment in patients with glaucoma. Based on the moderate correlation between visual field impairment and the VF-14 score, this questionnaire may be generalizable to patients with glaucoma. Several of the NEI-VFQ scales correlate with visual field impairment scores in patients with a wide range of glaucomatous damage. PMID:8981717

Comprehensive visual field test & diagnosis system in support of astronaut health and performance

NASA Astrophysics Data System (ADS)

Fink, Wolfgang; Clark, Jonathan B.; Reisman, Garrett E.; Tarbell, Mark A.

Long duration spaceflight, permanent human presence on the Moon, and future human missions to Mars will require autonomous medical care to address both expected and unexpected risks. An integrated non-invasive visual field test & diagnosis system is presented for the identification, characterization, and automated classification of visual field defects caused by the spaceflight environment. This system will support the onboard medical provider and astronauts on space missions with an innovative, non-invasive, accurate, sensitive, and fast visual field test. It includes a database for examination data, and a software package for automated visual field analysis and diagnosis. The system will be used to detect and diagnose conditions affecting the visual field, while in space and on Earth, permitting the timely application of therapeutic countermeasures before astronaut health or performance are impaired. State-of-the-art perimetry devices are bulky, thereby precluding application in a spaceflight setting. In contrast, the visual field test & diagnosis system requires only a touchscreen-equipped computer or touchpad device, which may already be in use for other purposes (i.e., no additional payload), and custom software. The system has application in routine astronaut assessment (Clinical Status Exam), pre-, in-, and post-flight monitoring, and astronaut selection. It is deployable in operational space environments, such as aboard the International Space Station or during future missions to or permanent presence on the Moon and Mars.

Projected impact of travoprost versus both timolol and latanoprost on visual field deficit progression and costs among black glaucoma subjects.

PubMed Central

Halpern, Michael T; Covert, David W; Robin, Alan L

2002-01-01

PURPOSE: We compared differences associated with use of travoprost and latanoprost on both progression of perimetric loss over time and associated costs among black patients. METHODS: Patients with primary open-angle glaucome or ocular hypertension were randomly assigned to one of four arms in a 12-month, double-masked study: travoprost (0.004% or 0.0015%), latanoprost (0.005%), or timolol (0.5%). Forty-nine patients received 0.004% travoprost, 43 received latanoprost, and 40 received timolol. We applied algorithms found in published studies that link intraocular pressure (IOP) control to visual field progression and calculated the likelihood of visual field deterioration based on IOP data. This was used to estimate differences in medical care costs. RESULTS: The average IOP was lower for patients receiving travoprost than for patients receiving latanoprost or timolol (17.3 versus 18.7 versus 20.5 mm Hg respectively, P < .05). Travoprost-treated patients had a smaller predicted change in visual field defect score (VFDS) than latanoprost-treated patients and timolol-treated patients, and significantly fewer were expected to demonstrate visual field progression. Medical care costs would be higher for latanoprost-treated and timolol-treated patients. CONCLUSIONS: Recent studies have provided algorithms linking IOP control to changes in visual fields. We found that treatment with travoprost was associated with less visual field progression and potential cost savings. PMID:12545683