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1

Neural Associations of the Early Retinotopic Cortex with the Lateral Occipital Complex during Visual Perception  

PubMed Central

Previous studies have demonstrated that the early retinotopic cortex (ERC, i.e., V1/V2/V3) is highly associated with the lateral occipital complex (LOC) during visual perception. However, it remains largely unclear how to evaluate their associations in quantitative way. The present study tried to apply a multivariate pattern analysis (MVPA) to quantify the neural activity in ERC and its association with that of the LOC when participants saw visual images. To this end, we assessed whether low-level visual features (Gabor features) could predict the neural activity in the ERC and LOC according to a voxel-based encoding model (VBEM), and then quantified the association of the neural activity between these regions by using an analogical VBEM. We found that the Gabor features remarkably predicted the activity of the ERC (e.g., the predicted accuracy was 52.5% for a participant) instead of that of the LOC (4.2%). Moreover, the MVPA approach can also be used to establish corresponding relationships between the activity patterns in the LOC and those in the ERC (64.2%). In particular, we found that the integration of the Gabor features and LOC visual information could dramatically improve the ‘prediction’ of ERC activity (88.3%). Overall, the present study provides new evidences for the possibility of quantifying the association of the neural activity between the regions of ERC and LOC. This approach will help to provide further insights into the neural substrates of the visual processing. PMID:25251083

Liang, Bishan; Liu, Bo; Liu, Ming; Huang, Ruiwang

2014-01-01

2

Functional Organization of Human Visual Cortex in Occipital Polymicrogyria  

E-print Network

Functional Organization of Human Visual Cortex in Occipital Polymicrogyria Serge O. Dumoulin,1 the function and organization of human polymicrogyric cortex using functional magnetic resonance imaging. Three areas. Our results suggest that human polymicrogyric cortex is not only organized in a normal fashion

Dumoulin, Serge O.

3

Two retinotopic visual areas in human lateral occipital cortex  

PubMed Central

We describe two visual field maps, LO1 and LO2, in human lateral occipital cortex between dorsal V3 and V5/MT+. Each map contained a topographic representation of the contralateral visual hemifield. The eccentricity representations were shared with V1/V2/V3. The polar angle representation in LO1 extended from the lower vertical meridian (at the boundary with dorsal V3) through the horizontal to the upper vertical meridian (at the boundary with LO2). The polar angle representation in LO2 was the mirror-reversal of that in LO1. LO1 and LO2 overlapped with the posterior part of the object-selective lateral occipital complex and the kinetic occipital region (KO). The retinotopy and functional properties of LO1 and LO2 suggest that they correspond to two new human visual areas, which lack exact homologues in macaque visual cortex. The topography, stimulus selectivity and anatomical location of LO1 and LO2 indicate that they integrate shape information from multiple visual submodalities in retinotopic coordinates. PMID:17182764

Larsson, Jonas; Heeger, David J

2007-01-01

4

Dynamic Coupling Between the Lateral Occipital-Cortex, Default-Mode, and Frontoparietal Networks During Bistable Perception  

PubMed Central

Abstract The lateral occipital cortex (LOC), a visual area known to be involved in object recognition, was dynamically coupled with each of two distributed patterns of neural activity depending upon the percept (default or alternative) elicited by a bistable figure. The two distributed patterns included core nodes of the default-mode and frontoparietal networks (FPN), and they were most highly coupled to each other during the alternative percept, whereas they were less coupled during the default percept. Surprisingly, the regions associated with the nonengaged percept exhibited the highest connectivity to the LOC. Together, these findings reveal a dynamic organization between the default mode and the FPNs, and the incoming bottom-up visual stream during perceptual binding of visual images. PMID:23510237

Karten, Ariel; Pantazatos, Spiro P.; Khalil, David; Zhang, Xian

2013-01-01

5

Topiramate modulates excitability of the occipital cortex when measured by transcranial magnetic stimulation  

Microsoft Academic Search

The aim of this study was to measure differences in occipital cortex excitability in migraineurs before and after administration of topiramate. We have previously demonstrated occipital cortex hyperexcitability in migraine using an objective technique of magnetic suppression of perceptual accuracy (MSPA). We hypothesized that a neuromodulator such as topiramate would demonstrate differences in MSPA in migraine compared with baseline. Ten

SK Aurora; PM Barrodale; AR Vermaas; CB Rudra

2010-01-01

6

Functional measurements of human ventral occipital cortex: retinotopy and colour.  

PubMed Central

Human colour vision originates in the cone photoreceptors, whose spatial density peaks in the fovea and declines rapidly into the periphery. For this reason, one expects to find a large representation of the cone-rich fovea in those cortical locations that support colour perception. Human occipital cortex contains several distinct foveal representations including at least two that extend onto the ventral surface: a region thought to be critical for colour vision. To learn more about these ventral signals, we used functional magnetic resonance imaging to identify visual field maps and colour responsivity on the ventral surface. We found a visual map of the complete contralateral hemifield in a 4 cm(2) region adjacent to ventral V3; the foveal representation of this map is confluent with that of areas V1/2/3. Additionally, a distinct foveal representation is present on the ventral surface situated 3-5 cm anterior from the confluent V1/2/3 foveal representations. This organization is not consistent with the definition of area V8, which assumes the presence of a quarter field representation adjacent to V3v. Comparisons of responses to luminance-matched coloured and achromatic patterns show increased activity to the coloured stimuli beginning in area V1 and extending through the new hemifield representation and further anterior in the ventral occipital lobe. PMID:12217168

Wade, Alex R; Brewer, Alyssa A; Rieger, Jochem W; Wandell, Brian A

2002-01-01

7

Mapping hV4 and ventral occipital cortex: The venous eclipse  

E-print Network

Mapping hV4 and ventral occipital cortex: The venous eclipse Department of Psychology, Stanford: The venous eclipse. Journal of Vision, 10(5):1, 1­22, http://journalofvision.org/content/10/5/1, doi:10

Wandell, Brian A.

8

Language processing in the occipital cortex of congenitally blind  

E-print Network

Humans are thought to have evolved brain regions in the left frontal and temporal cortex that are uniquely capable of language processing. However, congenitally blind individuals also activate the visual cortex in some ...

Bedny, Marina

9

Changing Human Visual Field Organization from Early Visual to Extra-Occipital Cortex  

PubMed Central

Background The early visual areas have a clear topographic organization, such that adjacent parts of the cortical surface represent distinct yet adjacent parts of the contralateral visual field. We examined whether cortical regions outside occipital cortex show a similar organization. Methodology/Principal Findings The BOLD responses to discrete visual field locations that varied in both polar angle and eccentricity were measured using two different tasks. As described previously, numerous occipital regions are both selective for the contralateral visual field and show topographic organization within that field. Extra-occipital regions are also selective for the contralateral visual field, but possess little (or no) topographic organization. A regional analysis demonstrates that this weak topography is not due to increased receptive field size in extra-occipital areas. Conclusions/Significance A number of extra-occipital areas are identified that are sensitive to visual field location. Neurons in these areas corresponding to different locations in the contralateral visual field do not demonstrate any regular or robust topographic organization, but appear instead to be intermixed on the cortical surface. This suggests a shift from processing that is predominately local in visual space, in occipital areas, to global, in extra-occipital areas. Global processing fits with a role for these extra-occipital areas in selecting a spatial locus for attention and/or eye-movements. PMID:17505546

Jack, Anthony I.; Patel, Gaurav H.; Astafiev, Serguei V.; Snyder, Abraham Z.; Akbudak, Erbil; Shulman, Gordon L.; Corbetta, Maurizio

2007-01-01

10

Shape-specific activation of occipital cortex in an early blind echolocation expert.  

PubMed

We have previously reported that an early-blind echolocating individual (EB) showed robust occipital activation when he identified distant, silent objects based on echoes from his tongue clicks (Thaler, Arnott, & Goodale, 2011). In the present study we investigated the extent to which echolocation activation in EB's occipital cortex reflected general echolocation processing per se versus feature-specific processing. In the first experiment, echolocation audio sessions were captured with in-ear microphones in an anechoic chamber or hallway alcove as EB produced tongue clicks in front of a concave or flat object covered in aluminum foil or a cotton towel. All eight echolocation sessions (2 shapes×2 surface materials×2 environments) were then randomly presented to him during a sparse-temporal scanning fMRI session. While fMRI contrasts of chamber versus alcove-recorded echolocation stimuli underscored the importance of auditory cortex for extracting echo information, main task comparisons demonstrated a prominent role of occipital cortex in shape-specific echo processing in a manner consistent with latent, multisensory cortical specialization. Specifically, relative to surface composition judgments, shape judgments elicited greater BOLD activity in ventrolateral occipital areas and bilateral occipital pole. A second echolocation experiment involving shape judgments of objects located 20° to the left or right of straight ahead activated more rostral areas of EB's calcarine cortex relative to location judgments of those same objects and, as we previously reported, such calcarine activity was largest when the object was located in contralateral hemispace. Interestingly, other echolocating experts (i.e., a congenitally blind individual in Experiment 1, and a late blind individual in Experiment 2) did not show the same pattern of feature-specific echo-processing calcarine activity as EB, suggesting the possible significance of early visual experience and early echolocation training. Together, our findings indicate that the echolocation activation in EB's occipital cortex is feature-specific, and that these object representations appear to be organized in a topographic manner. PMID:23391560

Arnott, Stephen R; Thaler, Lore; Milne, Jennifer L; Kish, Daniel; Goodale, Melvyn A

2013-04-01

11

Language processing in the occipital cortex of congenitally blind adults  

PubMed Central

Humans are thought to have evolved brain regions in the left frontal and temporal cortex that are uniquely capable of language processing. However, congenitally blind individuals also activate the visual cortex in some verbal tasks. We provide evidence that this visual cortex activity in fact reflects language processing. We find that in congenitally blind individuals, the left visual cortex behaves similarly to classic language regions: (i) BOLD signal is higher during sentence comprehension than during linguistically degraded control conditions that are more difficult; (ii) BOLD signal is modulated by phonological information, lexical semantic information, and sentence-level combinatorial structure; and (iii) functional connectivity with language regions in the left prefrontal cortex and thalamus are increased relative to sighted individuals. We conclude that brain regions that are thought to have evolved for vision can take on language processing as a result of early experience. Innate microcircuit properties are not necessary for a brain region to become involved in language processing. PMID:21368161

Bedny, Marina; Pascual-Leone, Alvaro; Dodell-Feder, David; Fedorenko, Evelina; Saxe, Rebecca

2011-01-01

12

The Involvement of Occipital Cortex in the Early Blind in Auditory and Tactile Duration Discrimination Tasks  

Microsoft Academic Search

Early blind participants outperform controls on several spatially oriented perceptual tasks such as sound localization and tactile orientation discrimination. Previous studies have suggested that the recruitment of occipital cortex in the blind is responsible for this improvement. For example, electroencephalographic studies showed an enlarged posterior negativity for the blind in these tasks compared to controls. In our study, the question

Rob H. J. Van der Lubbe; Christa M. Van Mierlo; Albert Postma

2009-01-01

13

The causal role of the occipital face area (OFA) and lateral occipital (LO) cortex in symmetry perception.  

PubMed

Symmetry is an important cue in face and object perception. Here we used fMRI-guided transcranial magnetic stimulation (TMS) to shed light on the role of the occipital face area (OFA), a key region in face processing, and the lateral occipital (LO) cortex, a key area in object processing, in symmetry detection. In the first experiment, we applied TMS over the rightOFA, its left homolog (leftOFA), rightLO, and vertex (baseline) while participants were discriminating between symmetric and asymmetric dot patterns. Stimulation of rightOFA and rightLO impaired performance, causally implicating these two regions in detection of symmetry in low-level dot configurations. TMS over rightLO but not rightOFA also significantly impaired detection of nonsymmetric shapes defined by collinear Gabor patches, demonstrating that rightOFA responds to symmetry but not to all cues mediating figure-ground segregation. The second experiment showed a causal role for rightOFA but not rightLO in facial symmetry detection. Overall, our results demonstrate that both the rightOFA and rightLO are sensitive to symmetry in dot patterns, whereas only rightOFA is causally involved in facial symmetry detection. PMID:25589766

Bona, Silvia; Cattaneo, Zaira; Silvanto, Juha

2015-01-14

14

Right Occipital Cortex Activation Correlates with Superior Odor Processing Performance in the Early Blind  

PubMed Central

Using functional magnetic resonance imaging (fMRI) in ten early blind humans, we found robust occipital activation during two odor-processing tasks (discrimination or categorization of fruit and flower odors), as well as during control auditory-verbal conditions (discrimination or categorization of fruit and flower names). We also found evidence for reorganization and specialization of the ventral part of the occipital cortex, with dissociation according to stimulus modality: the right fusiform gyrus was most activated during olfactory conditions while part of the left ventral lateral occipital complex showed a preference for auditory-verbal processing. Only little occipital activation was found in sighted subjects, but the same right-olfactory/left-auditory-verbal hemispheric lateralization was found overall in their brain. This difference between the groups was mirrored by superior performance of the blind in various odor-processing tasks. Moreover, the level of right fusiform gyrus activation during the olfactory conditions was highly correlated with individual scores in a variety of odor recognition tests, indicating that the additional occipital activation may play a functional role in odor processing. PMID:23967263

Grandin, Cécile B.; Dricot, Laurence; Plaza, Paula; Lerens, Elodie; Rombaux, Philippe; De Volder, Anne G.

2013-01-01

15

Object-Related Activity Revealed by Functional Magnetic Resonance Imaging in Human Occipital Cortex  

Microsoft Academic Search

The stages of integration leading from local feature analysis to object recognition were explored in human visual cortex by using the technique of functional magnetic resonance imaging. Here we report evidence for object-related activation. Such activation was located at the lateral-posterior aspect of the occipital lobe, just abutting the posterior aspect of the motion-sensitive area MT\\/V5, in a region termed

R. Malach; J. B. Reppas; R. R. Benson; K. K. Kwong; H. Jiang; W. A. Kennedy; P. J. Ledden; T. J. Brady; B. R. Rosen; R. B. H. Tootell

1995-01-01

16

Frontal–Occipital Connectivity During Visual Search  

PubMed Central

Abstract Although expectation- and attention-related interactions between ventral and medial prefrontal cortex and stimulus category-selective visual regions have been identified during visual detection and discrimination, it is not known if similar neural mechanisms apply to other tasks such as visual search. The current work tested the hypothesis that high-level frontal regions, previously implicated in expectation and visual imagery of object categories, interact with visual regions associated with object recognition during visual search. Using functional magnetic resonance imaging, subjects searched for a specific object that varied in size and location within a complex natural scene. A model-free, spatial-independent component analysis isolated multiple task-related components, one of which included visual cortex, as well as a cluster within ventromedial prefrontal cortex (vmPFC), consistent with the engagement of both top-down and bottom-up processes. Analyses of psychophysiological interactions showed increased functional connectivity between vmPFC and object-sensitive lateral occipital cortex (LOC), and results from dynamic causal modeling and Bayesian Model Selection suggested bidirectional connections between vmPFC and LOC that were positively modulated by the task. Using image-guided diffusion-tensor imaging, functionally seeded, probabilistic white-matter tracts between vmPFC and LOC, which presumably underlie this effective interconnectivity, were also observed. These connectivity findings extend previous models of visual search processes to include specific frontal–occipital neuronal interactions during a natural and complex search task. PMID:22708993

Pantazatos, Spiro P.; Yanagihara, Ted K.; Zhang, Xian; Meitzler, Thomas

2012-01-01

17

Occipital cortex activation by long-term repetitive tactile stimulation is necessary for object recognition in blinds: a case report.  

PubMed

Tactile vision has been approached from a variety of angles using different techniques. So far, a certain kind of object (and text) recognition has been shown, though seeing as such has not been achieved yet, and it remains unclear. Trough repetitive passive tactile stimulation perceptual processing is transferred from temporo-parietal to occipital areas, which affects object recognition. We report the results of passive tactile stimulation, as well as rTMS, applied to a 50 year old left handed blind male with over 97% loss of vision, who suffers from Peter's anomaly and microphthalmia. After 15 weeks of passive tactile stimulation, the subject showed increased activity in occipital areas associated with the development of visual-like perception which remained unchanged after three months without passive tactile stimulation. Inhibitory rTMS over the visual cortex led to noticeable reduction of spatial recognition performance and visual sensations in this subject. Stable changes in occipital cortical activity can be associated with subjective sensations of seeing. Once occipital activation has been achieved, it is necessary for spatial object recognition. Both facts highlight the implication of occipital areas in tactile vision and the cortical plasticity of passive tactile long-term stimulation in people with blindness. PMID:23819463

Ortiz, Tomás; Poch, Joaquín; Santos, Juan M; Martínez, Ana M; Ortiz-Terán, Laura; Requena, Carmen; Barcia, Juan A; de Erausquin, Gabriel A; Pascual-Leone, Alvaro

2014-06-01

18

Repetition suppression for speech processing in the associative occipital and parietal cortex of congenitally blind adults.  

PubMed

In the congenitally blind (CB), sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI). We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS) paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth. PMID:23717628

Arnaud, Laureline; Sato, Marc; Ménard, Lucie; Gracco, Vincent L

2013-01-01

19

Intracerebral electrical stimulation of a face-selective area in the right inferior occipital cortex impairs individual face discrimination.  

PubMed

During intracerebral stimulation of the right inferior occipital cortex, a patient with refractory epilepsy was transiently impaired at discriminating two simultaneously presented photographs of unfamiliar faces. The critical electrode contact was located in the most posterior face-selective brain area of the human brain (right "occipital face area", rOFA) as shown both by low- (ERP) and high-frequency (gamma) electrophysiological responses as well as a face localizer in fMRI. At this electrode contact, periodic visual presentation of 6 different faces by second evoked a larger electrophysiological periodic response at 6 Hz than when the same face identity was repeated at the same rate. This intracerebral EEG repetition suppression effect was markedly reduced when face stimuli were presented upside-down, a manipulation that impairs individual face discrimination. These findings provide original evidence for a causal relationship between the face-selective right inferior occipital cortex and individual face discrimination, independently of long-term memory representations. More generally, they support the functional value of electrophysiological repetition suppression effects, indicating that these effects can be used as an index of a necessary neural representation of the changing stimulus property. PMID:24936686

Jonas, Jacques; Rossion, Bruno; Krieg, Julien; Koessler, Laurent; Colnat-Coulbois, Sophie; Vespignani, Hervé; Jacques, Corentin; Vignal, Jean-Pierre; Brissart, Hélène; Maillard, Louis

2014-10-01

20

Spatial attention improves reliability of fMRI retinotopic mapping signals in occipital and parietal cortex  

E-print Network

% in lateral occipital (LO1, LO2) and posterior parietal (IPS0, IPS1, IPS2) cortical areas. Additionally, one 5. Retinotopic mapping refers to the process of characterizing topographic organization by identifying the visual of attention to a location in visual space improves processing of stimuli at that location. Speci cally, dire

Whitney, David

21

Neural mechanisms of feature conjunction learning: enduring changes in occipital cortex after a week of training.  

PubMed

Most visual activities, whether reading, driving, or playing video games, require rapid detection and identification of learned patterns defined by arbitrary conjunctions of visual features. Initially, such detection is slow and inefficient, but it can become fast and efficient with training. To determine how the brain learns to process conjunctions of visual features efficiently, we trained participants over eight consecutive days to search for a target defined by an arbitrary conjunction of color and location among distractors with a different conjunction of the same features. During each training session, we measured brain activity with functional magnetic resonance imaging (fMRI). The speed of visual search for feature conjunctions improved dramatically within just a few days. These behavioral improvements were correlated with increased neural responses to the stimuli in visual cortex. This suggests that changes in neural processing in visual cortex contribute to the speeding up of visual feature conjunction search. We find evidence that this effect is driven by an increase in the signal-to-noise ratio (SNR) of the BOLD signal for search targets over distractors. In a control condition where target and distractor identities were exchanged after training, learned search efficiency was abolished, suggesting that the primary improvement was perceptual learning for the search stimuli, not task-learning. Moreover, when participants were retested on the original task after nine months without further training, the acquired changes in behavior and brain activity were still present, showing that this can be an enduring form of learning and neural reorganization. PMID:23418123

Frank, Sebastian M; Reavis, Eric A; Tse, Peter U; Greenlee, Mark W

2014-04-01

22

Size matters: MEG empirical and simulation study on source localization of the earliest visual activity in the occipital cortex.  

PubMed

While the relationship between sensory stimulation and tasks and the size of the cortical activations is generally unknown, the visual modality offers a unique possibility of an experimental manipulation of stimulus size-related increases of the spatial extent of cortical activation even during the earliest activity in the retinotopically organized primary visual cortex. We used magnetoecephalography (MEG), visual stimuli of increasing size, and numerical simulations on realistic cortical surfaces to explore the effects of increasing spatial extent of the activated cortical sources on the neuromagnetic fields, location estimation biases, and source resolution. Source localization was performed assuming multiple dipoles in a sphere model using an efficient, automatically restarted multi-start simplex minimizer within the Calibrated Start Spatio-Temporal (CSST) algorithm. We found size-related effects on amplitude and latencies and differences in relative locations of the earliest occipital sources evoked by stimuli of increasing size presented at the same eccentricity. This finding was confirmed by single patch simulations. Additionally, simulations of multiple extended sources demonstrated size-related increase in limits in source resolution for bilaterally simulated sources, biases in location estimates for a given separation of sources, and limits in source resolution due to source multiplicity within a hemisphere. PMID:21476049

Golubic, Sanja Josef; Susac, Ana; Grilj, Veljko; Ranken, Douglas; Huonker, Ralph; Haueisen, Jens; Supek, Selma

2011-05-01

23

Vision After Early-Onset Lesions of the Occipital Cortex: I. Neuropsychological and Psychophysical Studies  

PubMed Central

We analyzed the visual functions of two patients (MS, FJ) with bilateral lesion of the primary visual cortex, which occurred at gestational age 33 wk in MS and at postnatal month 7 in FJ. In both patients basic visual functions— visual acuity, contrast sensitivity, color, form, motion perception—are similarly preserved or modestly impaired. Functions requiring higher visual processing, particularly figure-ground segregation based on textural cues, are severely impaired. In MS, studied longitudinally, the deficits attenuated between the ages of 4.5 and 8 y, suggesting that the developing visual system can display a considerable degree of adaptive plasticity several years after the occurrence of a lesion. In FJ (age 18:9 to 20:6 y), who is more impaired, the recovery, if any, was less. PMID:12458786

Kiper, D. C.; Zesiger, P.; Maeder, P.; Deonna, T.; Innocenti, G. M.

2002-01-01

24

The role of the lateral occipital cortex in aesthetic appreciation of representational and abstract paintings: A TMS study.  

PubMed

Neuroimaging studies of aesthetic appreciation have shown that activity in the lateral occipital area (LO)-a key node in the object recognition pathway-is modulated by the extent to which visual artworks are liked or found beautiful. However, the available evidence is only correlational. Here we used transcranial magnetic stimulation (TMS) to investigate the putative causal role of LO in the aesthetic appreciation of paintings. In our first experiment, we found that interfering with LO activity during aesthetic appreciation selectively reduced evaluation of representational paintings, leaving appreciation of abstract paintings unaffected. A second experiment demonstrated that, although the perceived clearness of the images overall positively correlated with liking, the detrimental effect of LO TMS on aesthetic appreciation does not owe to TMS reducing perceived clearness. Taken together, our findings suggest that object-recognition mechanisms mediated by LO play a causal role in aesthetic appreciation of representational art. PMID:25682351

Cattaneo, Zaira; Lega, Carlotta; Ferrari, Chiara; Vecchi, Tomaso; Cela-Conde, Camilo José; Silvanto, Juha; Nadal, Marcos

2015-04-01

25

Visual Recognition and Visually Guided Action After Early Bilateral Lesion of Occipital Cortex: A Behavioral Study of a 4.6-year-old Girl  

Microsoft Academic Search

We report the case of a 4.6-year-old girl born pre-term with early bilateral occipital damage. It was revealed that the child had non-severely impaired basic visual abilities and ocular motility, a selective perceptual deficit of figure-ground segregation, impaired visual recognition and abnormal navigating through space. Even if the child's visual functioning was not optimal, this was the expression of adaptive

Ileana Amicuzi; Massimo Stortini; Maurizio Petrarca; Paola Di Giulio; Giuseppe Di Rosa; Giuseppe Fariello; Daniela Longo; Vittorio Cannatà; Elisabetta Genovese; Enrico Castelli

2006-01-01

26

Occipital neuralgia: anatomic considerations.  

PubMed

Occipital neuralgia is a debilitating disorder first described in 1821 as recurrent headaches localized in the occipital region. Other symptoms that have been associated with this condition include paroxysmal burning and aching pain in the distribution of the greater, lesser, or third occipital nerves. Several etiologies have been identified in the cause of occipital neuralgia and include, but are not limited to, trauma, fibrositis, myositis, fracture of the atlas, and compression of the C-2 nerve root, C1-2 arthrosis syndrome, atlantoaxial lateral mass osteoarthritis, hypertrophic cervical pachymeningitis, cervical cord tumor, Chiari malformation, and neurosyphilis. The management of occipital neuralgia can include conservative approaches and/or surgical interventions. Occipital neuralgia is a multifactorial problem where multiple anatomic areas/structures may be involved with this pathology. A review of these etiologies may provide guidance in better understanding occipital neuralgia. PMID:25244129

Cesmebasi, Alper; Muhleman, Mitchel A; Hulsberg, Paul; Gielecki, Jerzy; Matusz, Petru; Tubbs, R Shane; Loukas, Marios

2015-01-01

27

Bilateral Occipital Condyle Fracture  

PubMed Central

Occipital condyle fractures are a rare finding in trauma victims. Bilateral fractures are even more unusual and have typically been reported in autopsy studies. We treated two patients with bilateral occipital condyle fractures who had only minor symptoms. Anderson and Montesano's classification,1 possible cranial nerve palsies, diagnosis, and treatment of this rare fracture are discussed. ImagesFigure 1Figure 2 PMID:17167657

Schrödel, Markus H.; Kestlmeier, Ralph; Trappe, Anna E.

2002-01-01

28

Memory for shape reactivates the lateral occipital complex.  

PubMed

Memory is thought to be a constructive process in which the cortical regions associated with processing event features are reactivated during retrieval. Although there is evidence for non-detailed cortical reactivation during retrieval (e.g., memory for visual or auditory information reactivates the visual or auditory processing regions, respectively), there is limited evidence that memory can reactivate cortical regions associated with processing detailed, feature-specific information. Such evidence is critical to our understanding of the mechanisms of episodic retrieval. The present functional magnetic resonance imaging (fMRI) study assessed whether the lateral occipital complex (LOC), a region that preferentially processes shape, is associated with retrieval of shape information. During encoding, participants were presented with colored abstract shapes that were either intact or scrambled. During retrieval, colored disks were presented and participants indicated whether the corresponding shape was previously "intact" or "scrambled". To assess whether conscious retrieval of intact shapes reactivated LOC, we conducted a conjunction of shape perception/encoding and accurate versus inaccurate retrieval of intact shapes, which produced many activations in LOC. To determine whether activity in LOC was specific to intact shapes, we conducted a conjunction of shape perception/encoding and intact versus scrambled shapes, which also produced many activations in LOC. Furthermore, memory for intact shapes in each hemifield produced contralateral activity in LOC (e.g., memory for left visual field intact shapes activated right LOC), which reflects the specific reinstatement of perception/encoding activity. The present results extend previous feature-specific memory reactivation evidence and support the view that memory is a constructive process. PMID:25623846

Karanian, Jessica M; Slotnick, Scott D

2015-04-01

29

Occipital nerve stimulation.  

PubMed

Occipital nerve stimulation (ONS) is a form of neuromodulation therapy aimed at treating intractable headache and craniofacial pain. The therapy utilizes neurostimulating electrodes placed subcutaneously in the occipital region and connected to a permanently implanted programmable pulse generator identical to those used for dorsal column/spinal cord stimulation. The presumed mechanisms of action involve modulation of the trigeminocervical complex, as well as closure of the physiologic pain gate. ONS is a reversible, nondestructive therapy, which can be tailored to a patient's individual needs. Typically, candidates for successful ONS include those patients with migraines, Chiari malformation, or occipital neuralgia. However, recent MRSA infections, unrealistic expectations, and psychiatric comorbidities are generally contraindications. As with any invasive procedure, complications may occur including lead migration, infection, wound erosion, device failure, muscle spasms, and pain. The success of this therapy is dependent on careful patient selection, a preimplantation trial, meticulous implantation technique, programming strategies, and complication avoidance. PMID:25411143

Mammis, Antonios; Agarwal, Nitin; Mogilner, Alon Y

2015-01-01

30

New type LOC adhesive tapes  

Microsoft Academic Search

A new technology of the plastic package is offered in volume production of 16 Mb DRAM. This new package, called the LOC (Lead On Chip) structured package, is characterized by directly bonding the lead frame to the surface of the chip with a adhesive tape. This technology requires some new type packaging materials. Adhesive tape is the key material used

Y. Okugawa; T. Yoshida; T. Suzuki; H. Nakayoshi

1994-01-01

31

FIRST PROOF Occipital Lobe  

E-print Network

pathways that lead to the brain. The smaller one goes to the superior colliculus, a nucleus is approximately 12% of the total surface area of the neocortex of the brain. Direct electrical stimulation and attention. Indeed, through exten- sive feedback to the occipital lobe and other lobes of the brain

Grill-Spector, Kalanit

32

Atlanto-occipital dislocation  

PubMed Central

Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death.

Hall, Graham C; Kinsman, Michael J; Nazar, Ryan G; Hruska, Rob T; Mansfield, Kevin J; Boakye, Maxwell; Rahme, Ralph

2015-01-01

33

Atlanto-occipital dislocation.  

PubMed

Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death. PMID:25793163

Hall, Graham C; Kinsman, Michael J; Nazar, Ryan G; Hruska, Rob T; Mansfield, Kevin J; Boakye, Maxwell; Rahme, Ralph

2015-03-18

34

Waves of awareness for occipital and parietal phosphenes perception.  

PubMed

Transcranial magnetic stimulation (TMS) of the occipital cortex is known to induce visual sensations, i.e. phosphenes, which appear as flashes of light in the absence of an external stimulus. Recent studies have shown that TMS can produce phosphenes also when the intraparietal sulcus (IPS) is stimulated. The main question addressed in this paper is whether parietal phosphenes are generated directly by local mechanisms or emerge through indirect activation of other visual areas. Electroencephalographic (EEG) signals were recorded while stimulating left occipital or parietal cortices inducing phosphene perception in healthy participants and in a hemianopic patient who suffered from complete destruction of the early visual cortex of the left hemisphere. Results in healthy participants showed that the onset of phosphene perception induced by occipital TMS correlated with differential cortical activity in temporal sites while the onset of phosphene perception induced by parietal TMS correlated with differential cortical activity in the stimulated parietal site. Moreover, IPS-TMS of the lesioned hemisphere of the hemianopic patient with a complete lesion to V1 showed again that the onset of phosphene perception correlated with differential cortical activity in the stimulated parietal site. The present data seem thus to suggest that temporal and parietal cortices can serve as different local early gatekeepers of perceptual awareness and that activity in the occipital cortex, although being relevant for perception in general, is not part of the neural bases of the perceptual awareness of phosphenes. PMID:25698639

Bagattini, Chiara; Mazzi, Chiara; Savazzi, Silvia

2015-04-01

35

Early processing in human LOC is highly responsive to illusory contours but not to salient regions  

PubMed Central

Human electrophysiological studies support a model whereby sensitivity to so-called illusory contour stimuli is first seen within the lateral occipital complex. A challenge to this model posits that the lateral occipital complex is a general site for crude region-based segmentation, based on findings of equivalent hemodynamic activations in the lateral occipital complex to illusory contour and so-called salient region stimuli, a stimulus class that lacks the classic bounding contours of illusory contours. Using high-density electrical mapping of visual evoked potentials, we show that early lateral occipital cortex activity is substantially stronger to illusory contour than to salient region stimuli, while later lateral occipital complex activity is stronger to salient region than to illusory contour stimuli. Our results suggest that equivalent hemodynamic activity to illusory contour and salient region stimuli likely reflects temporally integrated responses, a result of the poor temporal resolution of hemodynamic imaging. The temporal precision of visual evoked potentials is critical for establishing viable models of completion processes and visual scene analysis. We propose that crude spatial segmentation analyses, which are insensitive to illusory contours, occur first within dorsal visual regions, not lateral occipital complex, and that initial illusory contour sensitivity is a function of the lateral occipital complex. PMID:19895562

Shpaner, Marina; Murray, Micah M.; Foxe, John J.

2011-01-01

36

Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain  

E-print Network

Background: The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected. Results: Using ...

Gibson, Joanne H

37

Acute prefrontal cortex TMS in healthy volunteers: effects on brain 11C-alphaMtrp trapping.  

PubMed

High-frequency repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (LDLPFC) is a technique with purported efficacy as a treatment for major depression. Here, we assessed in vivo, in healthy volunteers, the effect of acute rTMS of the LDLPFC, relative to the stimulation of the left occipital cortex (LOC), on brain regional serotonin synthesis capacity, using the [(11)C]-alpha-methyl-tryptophan ((11)C-alphaMtrp)/PET method. Ten subjects were studied twice, once following rTMS of the LDLPFC and once following rTMS of the LOC in a randomized counterbalanced order. Three blocks of 15 trains of 10 Hz rTMS were delivered 10 min apart. Behavioural and autonomic measures were recorded before and after each rTMS session. Comparisons of TMS-related changes in regional normalized brain uptake and trapping of (11)C-alphaMtrp (K*) values were carried out using SPM99. Statistically significant regional differences were identified on the basis of an extent threshold of 50 voxels, with a peak threshold of p=0.005 uncorrected. Behavioural and autonomic measures were unaffected by rTMS. Relative to LOC stimulation, LDLPFC rTMS was associated with marked changes in normalized K* in limbic areas, with significantly lower values in the left parahippocampal gyrus (BA 28) and the right insula (BA 13), and higher values in the right cingulate gyrus (BA 31) and cuneus (BA 18). These findings indicate that acute rTMS of the LDLPFC in healthy volunteers modulates aspects of tryptophan/5-HT metabolism in limbic areas. Such adaptive changes may contribute to the mechanism of action of prefrontal rTMS in major depression. PMID:17188517

Sibon, I; Strafella, A P; Gravel, P; Ko, J H; Booij, L; Soucy, J P; Leyton, M; Diksic, M; Benkelfat, C

2007-02-15

38

Chiropractic management of greater occipital neuralgia  

Microsoft Academic Search

Greater occipital neuralgia (GON) is the term used to describe signs and symptoms of irritation to the greater occipital nerve. Neuralgic pain is characteristically sharp and shooting in nature and distributed over the area of the nerve affected. In the case of GON, pain is typically located in the sub-occipital region and radiates superiorly to the posterior aspect of the

L Comley

2003-01-01

39

Surviving atlanto-occipital dislocation.  

PubMed

Traumatic atlanto-occipital dislocation carries a significant mortality and morbidity. We present the clinical and radiological features of a case of traumatic skeletal and central nervous system disunion. Thanks to a combination of early resuscitation and luck, the patient survived an improbably severe injury to leave hospital and enjoy a degree of independent life. Such severe injuries are usually fatal and the literature on such extensive cervical disruption is often confined to postmortem evidence. PMID:17655644

Bloom, Benjamin M; Powell, Bruce P

2007-08-01

40

Occipital artery pseudoaneurysm: a rare scalp swelling.  

PubMed

Traumatic pseudoaneurysm occurring in face and temple is commonly reported to occur in superficial temporal artery, and so far only four cases have reported involvement of the occipital artery. We report a case of 25-year-old male patient presented to us with a pulsatile swelling in the occipital region following a trauma at the same site 5 years ago. A CT angiogram revealed the pseudoaneurysm of the left occipital artery and was surgically excised after ligation of proximal and distal parts along the course of the occipital artery. PMID:24426589

Nagpal, Nitin; Bhargava, Gopal Swaroop; Singh, Bhupinder

2013-06-01

41

Occipital cortical thickness predicts performance on pitch and musical tasks in blind individuals.  

PubMed

The behavioral and neurofunctional consequences of blindness often include performance enhancements and recruitment of occipital regions for nonvisual tasks. How the neuroanatomical changes resulting from this sensory loss relate to these functional changes is, however, less clear. Previous studies using cortical thickness (CT) measures have shown thicker occipital cortex in early-blind (EB) individuals compared with sighted controls. We hypothesized that this finding reflects the crossmodal plasticity often observed in blind individuals and thus could reflect behavioral adaptations. To address this issue, CT measures in blind (early and late) and sighted subjects were obtained along with several auditory behavioral measures in an attempt to relate behavioral and neuroanatomical changes. Group contrasts confirmed previous results in showing thicker occipital cortex in the EB. Regression analyses between CT measures across the whole brain of all blind individuals with the behavioral scores from 2 tasks in which EB subjects were superior (pitch and melody discrimination) showed that CT of occipital areas was directly related to behavioral enhancements. These findings constitute a compelling demonstration that anatomical changes in occipital areas are directly related to heightened behavioral abilities in the blind and hence support the idea that these anatomical features reflect adaptive compensatory plasticity. PMID:22095215

Voss, Patrice; Zatorre, Robert J

2012-11-01

42

Early ‘visual’ cortex activation correlates with superior verbal memory performance in the blind  

Microsoft Academic Search

The visual cortex may be more modifiable than previously considered. Using functional magnetic resonance imaging (fMRI) in ten congenitally blind human participants, we found robust occipital activation during a verbal-memory task (in the absence of any sensory input), as well as during verb generation and Braille reading. We also found evidence for reorganization and specialization of the occipital cortex, along

Noa Raz; Pazit Pianka; Rafael Malach; Ehud Zohary; Amir Amedi

2003-01-01

43

LEARNING AND ORGANIZATIONAL CHANGE (LOC) The Learning and Organizational Change concentration helps you explore how  

E-print Network

-based systems, involving people, technology and organizational structures and culture are a particular strength Culture and Cognition · LOC 306 Studies in Organizational Change · LOC 310 Learning OrganizationsLEARNING AND ORGANIZATIONAL CHANGE (LOC) CURRICULUM The Learning and Organizational Change

Shahriar, Selim

44

Human occipital cortices differentially exert saccadic suppression: intracranial recording in children  

PubMed Central

By repeating saccades unconsciously, humans explore the surrounding world every day. Saccades inevitably move external visual images across the retina at high velocity; nonetheless, healthy humans don’t perceive transient blurring of the visual scene during saccades. This perceptual stability is referred to as saccadic suppression. Functional suppression is believed to take place transiently in the visual systems, but it remains unknown how commonly or differentially the human occipital lobe activities are suppressed at the large-scale cortical network level. We determined the spatial-temporal dynamics of intracranially-recorded gamma activity at 80–150 Hz around spontaneous saccades under no-task conditions during wakefulness and those in darkness during REM sleep. Regardless of wakefulness or REM sleep, a small degree of attenuation of gamma activity was noted in the occipital regions during saccades, most extensively in the polar and least in the medial portions. Longer saccades were associated with more intense gamma-attenuation. Gamma-attenuation was subsequently followed by gamma-augmentation most extensively involving the medial and least involving the polar occipital region. Such gamma-augmentation was more intense during wakefulness and temporally locked to the offset of saccades. The polarities of initial peaks of perisaccadic event-related potentials (ERPs) were frequently positive in the medial and negative in the polar occipital regions. The present study, for the first time, provided the electrophysiological evidence that human occipital cortices differentially exert peri-saccadic modulation. Transiently suppressed sensitivity of the primary visual cortex in the polar region may be an important neural basis for saccadic suppression. Presence of occipital gamma-attenuation even during REM sleep suggests that saccadic suppression might be exerted even without external visual inputs. The primary visual cortex in the medial region, compared to the polar region, may be more sensitive to an upcoming visual scene provided at the offset of each saccade. PMID:23792979

Uematsu, Mitsugu; Matsuzaki, Naoyuki; Brown, Erik C.; Kojima, Katsuaki; Asano, Eishi

2013-01-01

45

Concurrent occipital hypoplasia, occipital dysplasia, syringohydromyelia, and hydrocephalus in a Yorkshire terrier  

PubMed Central

Magnetic resonance imaging of a 7.5-year-old neutered male Yorkshire terrier with mild generalized ataxia and intermittent neck scratching led to a diagnosis of caudal occipital malformation and syringohydromyelia. Surgical exploration led to a diagnosis of occipital dysplasia with concurrent occipital hypoplasia. Following a dorsal laminectomy of the first cervical vertebra there was no progression or improvement a month later. PMID:21037897

Cagle, Laura

2010-01-01

46

Third occipital nerve headache: a prevalence study.  

PubMed Central

A consecutive series of 100 patients was studied to determine the prevalence of third occipital nerve headache in patients with chronic neck pain (> three months in duration) after whiplash. Seventy one patients complained of headache associated with their neck pain. Headache was the dominant complaint of 40 patients, but was only a secondary problem for the other 31. Each patient with headache underwent double blind, controlled diagnostic blocks of the third occipital nerve. On two separate occasions the nerve was blocked with either lignocaine or bupivacaine, in random order. The diagnosis of third occipital nerve headache was made only if both blocks completely relieved the patient's upper neck pain and headache and the relief lasted longer with bupivacaine. The prevalence of third occipital nerve headache among all 100 whiplash patients was 27% (95% confidence interval (95% CI) 18-36%) and among those with dominant headache the prevalence was as high as 53% (95% CI 37-68%). There were no distinguishing features on history or examination that enabled a definitive diagnosis to be made before the nerve blocks. Those patients with a positive diagnosis, however, were significantly more likely to be tender over the C2-3 zygapophysial joint (p = 0.01). Third occipital nerve headache is a common condition in patients with chronic neck pain and headache after whiplash. Third occipital nerve blocks are essential to make this diagnosis. Images PMID:7931379

Lord, S M; Barnsley, L; Wallis, B J; Bogduk, N

1994-01-01

47

The role of the occipital face area in the cortical face perception network  

Microsoft Academic Search

Functional magnetic resonance imaging (fMRI) studies have identified spatially distinct face-selective regions in human cortex.\\u000a These regions have been linked together to form the components of a cortical network specialized for face perception but the\\u000a cognitive operations performed in each region are not well understood. In this paper, we review the evidence concerning one\\u000a of these face-selective regions, the occipital

David Pitcher; Vincent Walsh; Bradley Duchaine

2011-01-01

48

Occipital TMS at phosphene detection threshold captures attention automatically.  

PubMed

Strong stimuli may capture attention automatically, suggesting that attentional selection is determined primarily by physical stimulus properties. The mechanisms underlying capture remain controversial, in particular, whether feedforward subcortical processes are its main source. Also, it remains unclear whether only physical stimulus properties determine capture strength. Here, we demonstrate strong capture in the absence of feedforward input to subcortical structures such as the superior colliculus, by using transcranial magnetic stimulation (TMS) over occipital visual cortex as an attention cue. This implies that the feedforward sweep through subcortex is not necessary for capture to occur but rather provides an additional source of capture. Furthermore, seen cues captured attention more strongly than (physically identical) unseen cues, suggesting that the momentary state of the nervous system modulates attentional selection. In summary, we demonstrate the existence of several sources of attentional capture, and that both physical stimulus properties and the state of the nervous system influence capture. PMID:25600634

Rangelov, Dragan; Müller, Hermann J; Taylor, Paul C J

2015-04-01

49

LocSigDB: a database of protein localization signals  

PubMed Central

LocSigDB (http://genome.unmc.edu/LocSigDB/) is a manually curated database of experimental protein localization signals for eight distinct subcellular locations; primarily in a eukaryotic cell with brief coverage of bacterial proteins. Proteins must be localized at their appropriate subcellular compartment to perform their desired function. Mislocalization of proteins to unintended locations is a causative factor for many human diseases; therefore, collection of known sorting signals will help support many important areas of biomedical research. By performing an extensive literature study, we compiled a collection of 533 experimentally determined localization signals, along with the proteins that harbor such signals. Each signal in the LocSigDB is annotated with its localization, source, PubMed references and is linked to the proteins in UniProt database along with the organism information that contain the same amino acid pattern as the given signal. From LocSigDB webserver, users can download the whole database or browse/search for data using an intuitive query interface. To date, LocSigDB is the most comprehensive compendium of protein localization signals for eight distinct subcellular locations. Database URL: http://genome.unmc.edu/LocSigDB/ PMID:25725059

Negi, Simarjeet; Pandey, Sanjit; Srinivasan, Satish M.; Mohammed, Akram; Guda, Chittibabu

2015-01-01

50

LocSigDB: a database of protein localization signals.  

PubMed

LocSigDB (http://genome.unmc.edu/LocSigDB/) is a manually curated database of experimental protein localization signals for eight distinct subcellular locations; primarily in a eukaryotic cell with brief coverage of bacterial proteins. Proteins must be localized at their appropriate subcellular compartment to perform their desired function. Mislocalization of proteins to unintended locations is a causative factor for many human diseases; therefore, collection of known sorting signals will help support many important areas of biomedical research. By performing an extensive literature study, we compiled a collection of 533 experimentally determined localization signals, along with the proteins that harbor such signals. Each signal in the LocSigDB is annotated with its localization, source, PubMed references and is linked to the proteins in UniProt database along with the organism information that contain the same amino acid pattern as the given signal. From LocSigDB webserver, users can download the whole database or browse/search for data using an intuitive query interface. To date, LocSigDB is the most comprehensive compendium of protein localization signals for eight distinct subcellular locations. Database URL: http://genome.unmc.edu/LocSigDB/ PMID:25725059

Negi, Simarjeet; Pandey, Sanjit; Srinivasan, Satish M; Mohammed, Akram; Guda, Chittibabu

2015-01-01

51

[Simple partial seizure consisting of complex visual hallucinations due to left temporo-occipital lesion].  

PubMed

We report a case of simple partial seizure consisting of elementary visual hallucinations and complex visual hallucinations due to left temporo-occipital lesion. The patient was a 45-year-old right-handed female who has been suffering from paroxysmal visual hallucinations in her right visual field for 15 days before admission. The properties of the hallucinations included several round colorful figures, the upper torsos of people in red, and green trees. CT scan showed a small low density area which, limited to the basal part of the left temporal and occipital lobes, was complicated partially by a high density area that was thought to be calcified. On T2-weighted MRI images, the lesion was shown as a small oval-shaped high signal intensity area surrounded by a low signal intensity area, and from its characteristic findings, a cavernous angioma was suspected. On the EEG, epileptic discharge was observed in the area limited to the left occipital region when elementary visual hallucinations occurred, and high amplitude diffuse slow waves were revealed predominantly on the left when complex visual hallucinations developed. It was thought that elementary visual hallucinations occurred in this patient following epileptic discharge of the occipital lobe, and complex visual hallucinations developed secondarily to the discharge which expanded from the occipital lobe to the surrounding area. Considering the investigation of non-epileptic visual hallucinations that are observed in the hemianopic visual field, we believe that disturbances of function of the temporo-parietal lobes around the occipital visual cortex has an important role in causing the development of complex visual hallucinations. PMID:8905986

Takahashi, N; Kawamura, M

1996-05-01

52

Does Shape Discrimination by the Mouth Activate the Parietal and Occipital Lobes? – Near-Infrared Spectroscopy Study  

PubMed Central

A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS). Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7), extrastriate cortex (BA18, BA19), and striate cortex (BA17) activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7), extrastriate cortex (BA18, 19), and striate cortex (BA17), as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth. PMID:25299397

Kagawa, Tomonori; Narita, Noriyuki; Iwaki, Sunao; Kawasaki, Shingo; Kamiya, Kazunobu; Minakuchi, Shunsuke

2014-01-01

53

Atlanto-occipital disarticulation. Accident characteristics.  

PubMed

A retrospective study of cases of atlanto-occipital disarticulation was conducted to describe incident characteristics: 24 cases were identified, including nine motor vehicle drivers, two passengers, seven pedestrians, and five motorcyclists; one other person had fallen four stories. The highest rates were found among motorcyclists and pedestrians. Atlanto-occipital disarticulations occur in high-energy impacts and collisions and are associated with aortic laceration in 25% and basilar skull fracture in 21% of such cases. Current restraint systems and motorcycle helmets do not appear to prevent this generally rapidly fatal injury. PMID:2220702

Tepper, S L; Fligner, C L; Reay, D T

1990-09-01

54

Hypoplastic occipital condyle and third occipital condyle: review of their dysembryology.  

PubMed

Disruption or embryologic derailment of the normal bony architecture of the craniovertebral junction (CVJ) may result in symptoms. As studies of the embryology and pathology of hypoplasia of the occipital condyles and third occipital condyles are lacking in the literature, the present review was performed. Standard search engines were accessed and queried for publications regarding hypoplastic occipital condyles and third occipital condyles. The literature supports the notion that occipital condyle hypoplasia and a third occipital condyle are due to malformation or persistence of the proatlas, respectively. The Pax-1 gene is most likely involved in this process. Clinically, condylar hypoplasia may narrow the foramen magnum and lead to lateral medullary compression. Additionally, this maldevelopment can result in transient vertebral artery compression secondary to posterior subluxation of the occiput. Third occipital condyles have been associated with cervical canal stenosis, hypoplasia of the dens, transverse ligament laxity, and atlanto-axial instability causing acute and chronic spinal cord compression. Treatment goals are focused on craniovertebral stability. A better understanding of the embryology and pathology related to CVJ anomalies is useful to the clinician treating patients presenting with these entities. PMID:23338989

Tubbs, R Shane; Lingo, Patrick Ryan; Mortazavi, Martin M; Cohen-Gadol, Aaron A

2013-11-01

55

Adverse effect profile of lidocaine injections for occipital nerve block in occipital neuralgia.  

PubMed

To determine whether there are differences in the adverse effect profile between 1, 2 and 5% Lidocaine when used for occipital nerve blocks (ONB) in patients with occipital neuralgia. Occipital neuralgia is an uncommon cause of headaches. Little is known regarding the safety of Lidocaine injections for treatment in larger series of patients. Retrospective chart analysis of all ONB was performed at our headache clinic during a 6-year period on occipital neuralgia patients. 89 consecutive patients with occipital neuralgia underwent a total of 315 ONB. All the patients fulfilled the IHS criteria for Occipital Neuralgia. Demographic data were collected including age, gender, and ethnicity. The average age of this cohort was 53.25 years, and the majority of patients were females 69 (78%). Ethnicity of patients was diverse, with Caucasian 48(54%), Hispanics 31(35%), and others 10 (11%). 69 patients had 1%, 18 patients had 2% and 29 patient were given 5% Lidocaine. All Lidocaine injections were given with 20 mg Depo-medrol and the same injection technique and location were used for all the procedures. Eight patients (9%)had adverse effects to the Lidocaine and Depo-medrol injections, of which 5 received 5% and 3 received 1% Lidocaine. Majority of patients who had adverse effects were female 7(87%), and had received bilateral blocks (75%). ONB is a safe procedure with 1% Lidocaine; however, caution should be exerted with 5% in elderly patients, 70 or older, especially when administering bilateral injections. PMID:20665065

Sahai-Srivastava, Soma; Subhani, Dawood

2010-12-01

56

Occipitalized os odontoideum: A case report.  

PubMed

We report on a 36-year-old man presenting with a sudden onset of motor weakness and numbness in the upper extremities following a fall from a truck bed. Radiological findings demonstrated an os odontoideum and osseous continuity between the occiput and an ossicle, termed an "occipitalized os odontoideum." The occipitalized ossicle and atlas moved as a functional unit from the body of the axis. He underwent atlantoasxial stabilization with an atlas lateral mass screw and axis pedicle screw. Eighteen months later, he remained free of symptoms and showed solid bone fusion. Atlantoaxial stabilization resulted in an excellent clinical outcome for this condition. Our report provides useful knowledge regarding treatment of extremely rare osseous anomalies in the craniovertebral junction. PMID:25558149

Ohya, Junich; Miyoshi, Kota; Kitagawa, Tomoaki; Nakagawa, Shogo

2014-10-01

57

The timing of spheno-occipital fusion in hominoids.  

PubMed

The degree of spheno-occipital fusion has been used to assign a relative age to dentally mature hominoid cranial specimens. However, a recent study of captive individuals (Poe: Am J Phys Anthropol 144 (2011) 162–165) concluded that fusion of the spheno-occipital suture in great ape taxa is of little utility for aging dentally mature individuals. In this contribution, I use dentally mature samples of extant hominoid taxa (Homo sapiens, Pan troglodytes schweinfurthii, Gorilla gorilla gorilla, Pongo pygmaeus pygmaeus and Hylobates lar) to investigate a) the temporal relationship between spheno-occipital fusion and dental maturity, b) whether there is an association between the degree of spheno-occipital fusion and relative age, c) whether there are differences in relative timing of spheno-occipital fusion between taxa, and d) whether there are sex differences in the relative timing of spheno-occipital fusion. Results suggest that a) a substantial proportion of dentally mature wild-shot chimpanzee, gorilla and orang-utans have unfused or partially fused spheno-occipital synchondoses, b) there is an association between the degree of spheno-occipital fusion and age, c) there are interspecific differences in the timing of spheno-occipital fusion, and d) there are significant sex differences in spheno-occipital fusion in chimpanzees, orang-utans and gibbons. Thus, contrary to previous work, degree of spheno-occipital fusion is a potentially useful indicator of relative maturity, especially in great ape taxa. PMID:25293964

Balolia, Katharine L

2015-01-01

58

Amount of lifetime video gaming is positively associated with entorhinal, hippocampal and occipital volume.  

PubMed

Playing video games is a popular leisure activity among children and adults, and may therefore potentially influence brain structure. We have previously shown a positive association between probability of gray matter (GM) volume in the ventral striatum and frequent video gaming in adolescence. Here we set out to investigate structural correlates of video gaming in adulthood, as the effects observed in adolescents may reflect only a fraction of the potential neural long-term effects seen in adults. On magnetic resonance imaging (MRI) scans of 62 male adults, we computed voxel-based morphometry to explore the correlation of GM with the lifetime amount of video gaming (termed joystick years). We found a significant positive association between GM in bilateral parahippocamal region (entorhinal cortex) and left occipital cortex/inferior parietal lobe and joystick years (P<0.001, corrected for multiple comparisons). An exploratory analysis showed that the entorhinal GM volume can be predicted by the video game genres played, such as logic/puzzle games and platform games contributing positively, and action-based role-playing games contributing negatively. Furthermore, joystick years were positively correlated with hippocampus volume. The association of lifetime amount of video game playing with bilateral entorhinal cortex, hippocampal and occipital GM volume could reflect adaptive neural plasticity related to navigation and visual attention. PMID:23958958

Kühn, S; Gallinat, J

2014-07-01

59

The occipital torus and developmental age of Sangiran-3  

Microsoft Academic Search

Since its discovery in 1938 Sangiran-3 has been considered a juvenilePithecanthropus(Homo)erectusand therefore, excluded from studies of adultH. erectusAlthough morphological features align Sangiran-3 withH. erectusits age designation rests on an unconvincing reconstruction of the occipital torus and lack of sutural fusion. Evaluation of the occipital shows the original reconstruction is faulty and that the current midline occipital torus is actually the

Susan C. Antón; Jens Lorenz Franzen

1997-01-01

60

TMS to the "occipital face area" affects recognition but not categorization of faces.  

PubMed

The human cortical system for face perception is comprised of a network of connected regions including the middle fusiform gyrus ("fusiform face area" or FFA), the inferior occipital cortex ("occipital face area" or OFA), and the superior temporal sulcus. The traditional hierarchical feedforward model of visual processing suggests information flows from early visual cortex to the OFA for initial face feature analysis to higher order regions including the FFA for identity recognition. However, patient data suggest an alternative model. Patients with acquired prosopagnosia, an inability to visually recognize faces, have been documented with lesions to the OFA but who nevertheless show face-selective activation in the FFA. Moreover, their ability to categorize faces remains intact. This suggests that the FFA is not solely responsible for face recognition and the network is not strictly hierarchical, but may be organized in a reverse hierarchical fashion. We used transcranial magnetic stimulation (TMS) to temporarily disrupt processing in the OFA in neurologically-intact individuals and found participants' ability to categorize intact versus scrambled faces was unaffected, however face identity discrimination was significantly impaired. This suggests that face categorization but not recognition can occur without the "earlier" OFA being online and indicates that "lower level" face category processing may be assumed by other intact face network regions such as the FFA. These results are consistent with the patient data and support a non-hierarchical, global-to-local model with re-entrant connections between the OFA and other face processing areas. PMID:24077427

Solomon-Harris, Lily M; Mullin, Caitlin R; Steeves, Jennifer K E

2013-12-01

61

Reorganization of Retinotopic Maps after Occipital Lobe Infarction  

E-print Network

U ncorrected Proof Reorganization of Retinotopic Maps after Occipital Lobe Infarction Lucia M , and Alan Cowey3,4* Abstract We studied patient JS, who had a right occipital infarct that encroached used fMRI to perform retinotopic mapping at 3, 8, and 11 months after the infarct. We quantified

Vaina, Lucia M.

62

Reorganization of Retinotopic Maps after Occipital Lobe Infarction  

E-print Network

Reorganization of Retinotopic Maps after Occipital Lobe Infarction Lucia M. Vaina1,2,3 , Sergei,4* Abstract We studied patient JS, who had a right occipital infarct that encroached on visual areas V1, V2vMRI to perform retinotopic mapping at 3, 8, and 11 months after the infarct. We quantified the retinotopy

Vaina, Lucia M.

63

Feasibility of a visual prosthesis for the blind based on intracorticai microstimulation of the visual cortex  

Microsoft Academic Search

Summary The feasibility of producing a visual prosthesis for the blind using intracorticai microstimulation (ICMS) of the visual cortex was studied in a 42-year-old woman who had been totally blind for 22 years secondary to glaucoma. Thirty- eight microelectrodes were implanted in the right visual cortex, near the occipital pole, for a period of 4 months. Percepts reported as small

E. M. Schmidt; M. J. Bak; F. T. Hambrecht; C. V. Kufta; D. K. O'Rourke; P. Vallabhanath

64

Traumatic atlanto-occipital dislocation in children.  

PubMed

Although once considered an invariably fatal injury, improvements in diagnosis and management have made atlanto-occipital dislocation (AOD) a survivable injury. MRI is the preferred imaging modality; occasionally, flexion/extension/distraction fluoroscopy may be required to determine craniovertebral stability. Early surgical stabilization is recommended for all children with AOD. Early occipitocervical fusion using screws in combination with a rod or plate, or sublaminar wires with a contoured rod, coupled with autograft bone, provide immediate stabilization and a high fusion rate. Halo immobilization and traction are contraindicated in the management of AOD in children because of the risk of displacement of the injured occipitocervical joint. Postoperative hydrocephalus is frequent and should be suspected when neurologic decline occurs after fixation. Nearly half of children who survive AOD will have residual neurologic deficits. PMID:24788443

Astur, Nelson; Sawyer, Jeffrey R; Klimo, Paul; Kelly, Derek M; Muhlbauer, Michael; Warner, William C

2014-05-01

65

Cooled Radiofrequency Ablation for Bilateral Greater Occipital Neuralgia  

PubMed Central

This report describes a case of bilateral greater occipital neuralgia treated with cooled radiofrequency ablation. The case is considered in relation to a review of greater occipital neuralgia, continuous thermal and pulsed radiofrequency ablation, and current medical literature on cooled radiofrequency ablation. In this case, a 35-year-old female with a 2.5-year history of chronic suboccipital bilateral headaches, described as constant, burning, and pulsating pain that started at the suboccipital region and radiated into her vertex. She was diagnosed with bilateral greater occipital neuralgia. She underwent cooled radiofrequency ablation of bilateral greater occipital nerves with minimal side effects and 75% pain reduction. Cooled radiofrequency ablation of the greater occipital nerve in challenging cases is an alternative to pulsed and continuous RFA to alleviate pain with less side effects and potential for long-term efficacy. PMID:24716017

Chhatre, Akhil

2014-01-01

66

Supra- and infra-torcular double occipital encephalocele.  

PubMed

An encephalocele is a protrusion of the brain and/or meninges through a defect in the skull that is closed or covered with skin. Occipital encephaloceles are the most frequent type in North America and Western Europe, where about 85% of encephaloceles take this form. To the best of our knowledge, there are only three other reported cases of double occipital encephaloceles in the literature. The current study reports a double and both supra- and infra-torcular occipital encephalocele in a neonate and discusses the importance of preoperative neuroimaging studies to optimize the outcome. The patient was a 1-day-old male child who was identified by prenatal ultrasound to have two occipital encephaloceles. The patient underwent a closure of the occipital encephalocele on the second postnatal day. The infant tolerated the procedure well and was extubated on the first postoperative day. The child continues to do well during follow-up. PMID:25307275

Canaz, Hüseyin; Ayçiçek, Ezgi; Akçetin, Mustafa Ali; Akdemir, Osman; Alata?, Ibrahim; Özdemir, Bülent

2015-01-01

67

Response to occipital nerve block is not useful in predicting efficacy of occipital nerve stimulation.  

PubMed

Occipital nerve stimulation (ONS) may be effective for the treatment of headaches that are recalcitrant to medical therapy. The objective of this study was to determine if response to occipital nerve block (ONB) predicts response to ONS in patients with chronic, medically intractable headaches. We evaluated 15 patients who underwent placement of occipital nerve stimulators for the treatment of chronic headaches. Data were collected regarding analgesic response to ONB and to ONS. Nine of 15 patients were ONS responders (> or =50% reduction in headache frequency or severity). Thirteen patients had ONB prior to stimulator implantation. Ten of 13 who had ONB had significant relief of head pain lasting at least 24 h, and three were ONB non-responders. Of the three ONB non-responders, two were ONS responders. Of the two patients who did not have ONB prior to ONS, one was an ONS responder and one was an ONS non-responder. In conclusion, analgesic response to ONB may not be predictive of the therapeutic effect from ONS in patients with medically refractory chronic headaches. PMID:17381559

Schwedt, T J; Dodick, D W; Trentman, T L; Zimmerman, R S

2007-03-01

68

A case of occipitalization in the human skull.  

PubMed

Occipitalization of the atlas is an osseous anomaly of the craniovertebral junction. The aim of this paper is to present an anatomical variant of the fused atlas with the occipital bone and discuss similar cases described in literature. The skull of an adult male analysed in this study belonged to the cranial collection of the Department of Anatomy of the Jagiellonian University, Medical Collage. A tight bony fusion between the anterior arch of the atlas, the left portion of the posterior arch, the lateral masses of the atlas, and the occipital bone was observed. Hence, the left and right superior articular facets of the atlas were fused with the corresponding occipital condyles. The anteroposterior dimension of both inferior articular facets was the same (20 mm), while the transverse diameter of the right one was considerably smaller (12 mm). The transverse diameter of the left inferior articular facets was 17 mm. The right and the left transverse process of the atlas were normally developed, each of them contained transverse foramen, and they were not fused with the occipital bone. The circumference of the foramen magnum was minimally diminished by the osseous structures of the atlas fused to the occipital bone. The sagittal and transverse diameters of the foramen magnum (38 mm x 34 mm) were within the normal range of variation. However, the asymmetrical anatomy of the inferior articular facets of the atlas give rise to speculation that movement in the atlantoaxial joint was disturbed by assimilation with the occipital bone. PMID:21154282

Skrzat, J; Mróz, I; Jaworek, J K; Walocha, J

2010-08-01

69

Non-traumatic posterior atlanto-occipital joint dislocation.  

PubMed

This report presents a case of non-traumatic posterior atlanto-occipital dislocation. A 36-year-old female was referred with a history of numbness of the extremities, vertigo and neck pain for 1 year. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. A lateral cervical radiograph in the neutral position demonstrated a posterior atlanto-occipital dislocation. A coronal view on a computed tomography (CT) reconstruction image showed a loss of angle of the bilateral atlanto-occipital joint, and a sagittal reconstruction view of CT images also demonstrated flatness of atlanto-occipital joint. Instrumented occipito-cervical fusion was performed after reduction. A lateral cervical radiograph in the neutral position 1 year after surgery showed the reduction of atlanto-occipital joint, moreover, it was maintained even in an extended position. The patient had neurologic improvement after surgery. Flatness of the bilateral atlanto-occipital joint may have induced this instability. Occipital-cervical fusion was chosen in the present case since the patient showed restricted axial rotation of the neck before surgery. The surgery improved the preoperative symptoms including the function of cervical spine evaluated by JOACMEQ. PMID:20549257

Takechi, Yasuhiko; Iizuka, Haku; Sorimachi, Yasunori; Ara, Tsuyoshi; Nishinome, Masahiro; Takagishi, Kenji

2011-07-01

70

Anton's Syndrome due to Bilateral Ischemic Occipital Lobe Strokes  

PubMed Central

We present a case of a patient with Anton's syndrome (i.e., visual anosognosia with confabulations), who developed bilateral occipital lobe infarct. Bilateral occipital brain damage results in blindness, and patients start to confabulate to fill in the missing sensory input. In addition, the patient occasionally becomes agitated and talks to himself, which indicates that, besides Anton's syndrome, he might have had Charles Bonnet syndrome, characterized by both visual loss and hallucinations. Anton syndrome, is not so frequent condition and is most commonly caused by ischemic stroke. In this particular case, the patient had successive bilateral occipital ischemia as a result of massive stenoses of head and neck arteries. PMID:25530893

Zuki?, Sanela; Sinanovi?, Osman; Hodži?, Renata; Mujagi?, Svjetlana; Smajlovi?, Edina

2014-01-01

71

Neonatal apneic seizure of occipital lobe origin: continuous video-EEG recording.  

PubMed

We present 2 term newborn infants with apneic seizure originating in the occipital lobe that was diagnosed by video-EEG. One infant had ischemic infarction in the distribution of the posterior cerebral artery, extending to the cingulate gyrus. In the other infant, only transient occipital hyperechogenicity was observed by using neurosonography. In both cases, although the critical EEG discharge was observed at the occipital level, the infants presented no clinical manifestations. In patient 1, the discharge extended to the temporal lobe first, with subtle motor manifestations and tachycardia, then synchronously to both hemispheres (with bradypnea/hypopnea), and the background EEG activity became suppressed, at which point the infant experienced apnea. In patient 2, background EEG activity became suppressed right at the end of the focal discharge, coinciding with the appearance of apnea. In neither case did the clinical description by observers coincide with video-EEG findings. The existence of connections between the posterior limbic cortex and the temporal lobe and midbrain respiratory centers may explain the clinical symptoms recorded in these 2 cases. The novel features reported here include video-EEG capture of apneic seizure, ischemic lesion in the territory of the posterior cerebral artery as the cause of apneic seizure, and the appearance of apnea when the epileptiform ictal discharge extended to other cerebral areas or when EEG activity became suppressed. To date, none of these clinical findings have been previously reported. We believe this pathology may in fact be fairly common, but that video-EEG monitoring is essential for diagnosis. PMID:22641764

Castro Conde, José Ramón; González-Hernández, Tomás; González Barrios, Desiré; González Campo, Candelaria

2012-06-01

72

3.2 "Lab-on-a-Chip" A Lab-on-a-Chip (LOC) device, also known as a micro-total-analytical system  

E-print Network

shows an example of an LOC device that was tested on the International Space Station in 2007. Figure 28: LOC device tested on the International Space Station in 2007 At the heart of LOC devices are "chips

73

Low single dose gabapentin does not affect prefrontal and occipital gamma-aminobutyric acid concentrations.  

PubMed

The ?-aminobutyric acid (GABA) system has been proposed as a target for novel antidepressant and anxiolytic treatments. Emerging evidence suggests that gabapentin (GBP), an anticonvulsant drug that significantly increases brain GABA levels, is effective in the treatment of anxiety disorders. The current study was designed to measure prefrontal and occipital GABA levels in medication-free healthy subjects after taking 0mg, 150mg and 300mg GBP. Subjects were scanned on a 3T scanner using a transmit-receive head coil that provided a relatively homogenous radiofrequency field to obtain spectroscopy measurement in the medial prefrontal (MPFC) and occipital cortex (OCC). There was no dose-dependent effect of GBP on GABA levels in the OCC or MPFC. There was also no effect on Glx, choline or N-acetyl-aspartate concentrations. The previously reported finding of increased GABA levels after GBP treatment is not evident for healthy subjects at the dose of 150 and 300mg. As a result, if subjects are scanned on a 3T scanner, low dose GPB is not useful as an experimental challenge agent on the GABA system. PMID:24071367

Preuss, Nora; van der Veen, Jan Willem; Carlson, Paul J; Shen, Jun; Hasler, Gregor

2013-12-01

74

Occipital condyle to cervical spine fixation in the pediatric population.  

PubMed

Fixation at the craniovertebral junction (CVJ) is necessary in a variety of pediatric clinical scenarios. Traditionally an occipital bone to cervical fusion is preformed, which requires a large amount of hardware to be placed on the occiput of a child. If a patient has previously undergone a posterior fossa decompression or requires a decompression at the time of the fusion procedure, it can be difficult to anchor a plate to the occipital bone. The authors propose a technique that can be used when faced with this difficult challenge by using the occipital condyle as a point of fixation for the construct. Adult cadaveric and a limited number of case studies have been published using occipital condyle (C-0) fixation. This work was adapted for the pediatric population. Between 2009 and 2012, 4 children underwent occipital condyle to axial or subaxial spine fixation. One patient had previously undergone posterior fossa surgery for tumor resection, and 1 required decompression at the time of operation. Two patients underwent preoperative deformity reduction using traction. One child had a Chiari malformation Type I. Each procedure was performed using polyaxial screw-rod constructs with intraoperative neuronavigation supplemented by a custom navigational drill guide. Smooth-shanked 3.5-mm polyaxial screws, ranging in length from 26 to 32 mm, were placed into the occipital condyles. All patients successfully underwent occipital condyle to cervical spine fixation. In 3 patients the construct extended from C-0 to C-2, and in 1 from C-0 to T-2. Patients with preoperative halo stabilization were placed in a cervical collar postoperatively. There were no new postoperative neurological deficits or vascular injuries. Each patient underwent postoperative CT, demonstrating excellent screw placement and evidence of solid fusion. Occipital condyle fixation is an effective option in pediatric patients requiring occipitocervical fusion for treatment of deformity and/or instability at the CVJ. The use of intraoperative neuronavigation allows for safe placement of screws into C-0, especially when faced with a challenging patient in whom fixation to the occipital bone is not possible or is less than ideal. PMID:24206344

Kosnik-Infinger, Libby; Glazier, Steven S; Frankel, Bruce M

2014-01-01

75

Innervation of sonic muscles in teleosts: occipital vs. spinal nerves.  

PubMed

The innervation of sonic muscles in teleosts has been categorized into three types: occipital nerve, spinal nerve, and a combination of occipital and spinal nerves. The innervation patterns of sonic muscles were examined (or re-examined) in seven sonic fish species (rockfish, pinecone fish, sweeper, tigerfish, piranha, dory, and pollack) that use the sonic muscles to vibrate the swimbladder. The peripheral nerves (occipital or spinal) were identified based on skeletal preparations. The sonic muscle innervation was of the occipital type in four species (rockfish, pinecone fish, sweeper, and tigerfish) and of the spinal type in three species (piranha, dory, and pollack); none of the seven species examined showed the combination type. Therefore, we hypothesized that innervation patterns could be divided simply into occipital and spinal types. Moreover, the present results revealed that previously reported innervation patterns are inaccurate for three species (tigerfish, piranha, and dory) re-examined in this study. Therefore, it is important to define the peripheral nerves precisely, by using skeletal preparations, in future investigations of sonic muscle innervation. PMID:17230021

Onuki, Atsushi; Somiya, Hiroaki

2007-01-01

76

Imaging features of atlanto-occipital overlapping in dogs.  

PubMed

The imaging features of four dogs with atlanto-occipital overlapping are described. This malformation appeared to play a role in the development of neck pain, ataxia, variable cerebellar involvement, medullary kinking, and possibly syringomyelia. Using cervical radiographs, three of the four dogs were initially diagnosed with an atlanto-axial malformation. Because this disorder could not account for all clinical signs, magnetic resonance and computed tomography images were also acquired. These provided a more complete evaluation of the craniocervical junction, allowing detection of atlanto-occipital overlapping, medullary kinking, occipital dysplasia, abnormalities of the dens, and syringomyelia in these dogs. Head position during imaging affected the degree of atlanto-occipital overlap. These findings emphasize the need to modify the currently accepted imaging recommendations for dogs with head and neck pain and/or cranial cervical myelopathy. We suggest that the entire craniocervical junction be evaluated, even if atlanto-axial subluxation has already been detected. Moreover, we propose that atlanto-occipital overlapping is a perhaps underrecognized disorder that can influence the clinical signs and therapeutic outcome of dogs with anomalies of the craniocervical junction. PMID:19507388

Cerda-Gonzalez, Sofia; Dewey, Curtis W; Scrivani, Peter V; Kline, Karen L

2009-01-01

77

Expression of Recombinant Protein Encoded by LOC387715 in Escherichia coli  

PubMed Central

LOC387715 is a hypothetical gene located on human chromosome 10q26.13 that is associated with the development of age-related macula degeneration (AMD). The native open reading frame (ORF) of LOC387715 cDNA – LOC387715(ORF), contains a large number of Escherichia coli (E. coli) rare codons (RC) including 5.6% and 15.0% Group-I and IIa translational problem causative (TPC) RCs respectively, which forms 3 and 4 simple E. coli rare codon clusters (RCC) where RCs are spaced by 1 and 2 respective non-TPC codons and one complex E. coli RCC where RCs and RCCs are spaced by < 5 non-TPC codons. We modified the entire 35 E. coli RCs (6, 16 and 13 Group I, IIa and IIb RCs respectively) present in LOC387715(ORF) with their optimal or sub-optimal synonymous degenerate codons, and the resulted LOC387715(ORF)m was free from Shine-Dalgarno-like sequence (SDLS) and ribosome binding site complementary sequence (RBSCS). SDS-PAGE and Western blotting analysis demonstrated that LOC387715(ORF)m was capable of highly expressing the recombinant protein rLOC387715 in E. coli. Mass spectrometry analysis indicated that the bacterial expressed rLOC387715 contained the correct and expected amino acid (aa) sequence without aa misincorporation, aa missing or frame-shift. The results suggest that high and authentic expression of LOC387715 recombinant protein in E. coli was achieved by the synonymous modification of its native ORF cDNA sequence for all the 3 groups of bacterial RCs and the simultaneous elimination of SDLS and RBSCS sequences. PMID:17485225

Chen, Dequan; Langford, Marlyn P.; Duggan, Chris; Madden, Benjamin J.; Edwards, Albert O.

2009-01-01

78

[Traumatic atlanto-occipital dislocation in a calf].  

PubMed

In a 7-week-old calf neurologic symptoms occurred after an accident in the feeding grid. The calf was alert but in left lateral recumbency. After having been placed on its right side it showed a sideward drift to the left. Following head movement, an asynchronous movement of the eyes could be observed. Lesions of the upper motor neuron system, N. vestibulocochlearis, Nn. oculomotorius, trochlearis and/or abducens as well as N. vagus were suspected. Radiological examination of the occipital region and cervical spine revealed an atlanto-occipital subluxation of the atlas. Based on all these findings, the diagnosis of traumatic atlanto-occipital dislocation was made and the calf was euthanized. The pathological findings confirmed this diagnosis. PMID:22331290

Knubben-Schweizer, G; Friedrich, A; Ebert, U; Hördemann, M; Hagen, R; Nuss, K

2012-01-01

79

Rapid and Reversible Recruitment of Early Visual Cortex for Touch  

PubMed Central

Background The loss of vision has been associated with enhanced performance in non-visual tasks such as tactile discrimination and sound localization. Current evidence suggests that these functional gains are linked to the recruitment of the occipital visual cortex for non-visual processing, but the neurophysiological mechanisms underlying these crossmodal changes remain uncertain. One possible explanation is that visual deprivation is associated with an unmasking of non-visual input into visual cortex. Methodology/Principal Findings We investigated the effect of sudden, complete and prolonged visual deprivation (five days) in normally sighted adult individuals while they were immersed in an intensive tactile training program. Following the five-day period, blindfolded subjects performed better on a Braille character discrimination task. In the blindfold group, serial fMRI scans revealed an increase in BOLD signal within the occipital cortex in response to tactile stimulation after five days of complete visual deprivation. This increase in signal was no longer present 24 hours after blindfold removal. Finally, reversible disruption of occipital cortex function on the fifth day (by repetitive transcranial magnetic stimulation; rTMS) impaired Braille character recognition ability in the blindfold group but not in non-blindfolded controls. This disruptive effect was no longer evident once the blindfold had been removed for 24 hours. Conclusions/Significance Overall, our findings suggest that sudden and complete visual deprivation in normally sighted individuals can lead to profound, but rapidly reversible, neuroplastic changes by which the occipital cortex becomes engaged in processing of non-visual information. The speed and dynamic nature of the observed changes suggests that normally inhibited or masked functions in the sighted are revealed by visual loss. The unmasking of pre-existing connections and shifts in connectivity represent rapid, early plastic changes, which presumably can lead, if sustained and reinforced, to slower developing, but more permanent structural changes, such as the establishment of new neural connections in the blind. PMID:18728773

Merabet, Lotfi B.; Hamilton, Roy; Schlaug, Gottfried; Swisher, Jascha D.; Kiriakopoulos, Elaine T.; Pitskel, Naomi B.; Kauffman, Thomas; Pascual-Leone, Alvaro

2008-01-01

80

Recurrent Bilateral Occipital Infarct with Cortical Blindness and Anton Syndrome  

PubMed Central

Bilateral cortical blindness and Anton syndrome, are most commonly caused by ischaemic stroke. In this condition, patients have loss of vision but deny their blindness despite objective evidence of visual loss. We report a case of a patient with multiple cardiovascular risk factors who developed recurrent bilateral occipital lobe infarct with Anton syndrome. A suspicion of this condition should be raised when the patient has denial of blindness in the presence of clinical and radiological evidence of occipital lobe injury. Management of this condition should focus on the underlying cause, in which our patient requires secondary stroke prevention and rehabilitation. PMID:24744933

Kwong Yew, Kiu; Abdul halim, Sanihah; Tharakan, John

2014-01-01

81

Recurrent bilateral occipital infarct with cortical blindness and anton syndrome.  

PubMed

Bilateral cortical blindness and Anton syndrome, are most commonly caused by ischaemic stroke. In this condition, patients have loss of vision but deny their blindness despite objective evidence of visual loss. We report a case of a patient with multiple cardiovascular risk factors who developed recurrent bilateral occipital lobe infarct with Anton syndrome. A suspicion of this condition should be raised when the patient has denial of blindness in the presence of clinical and radiological evidence of occipital lobe injury. Management of this condition should focus on the underlying cause, in which our patient requires secondary stroke prevention and rehabilitation. PMID:24744933

Kwong Yew, Kiu; Abdul Halim, Sanihah; Liza-Sharmini, Ahmad Tajudin; Tharakan, John

2014-01-01

82

Grievous Temporal and Occipital Injury Caused by a Bear Attack  

PubMed Central

Bear attacks are reported from nearly every part of the world. The chance of a human encountering a bear increases as the remote bear territory diminishes. The sloth bear is one of the three species of bears found in India, which inhabits the forests of India and its neighboring countries. Here we describe a teenager who came to us with a critical injury involving the face, temporal and occipital bones inflicted by a sloth bear attack. He underwent a temporal exploration, facial nerve decompression, pinna reconstruction, and occipital bone repair to save him from fatality. PMID:24396623

Thada, Nikhil Dinaker; Rao, Pallavi; Thada, Smitha Rani; Prasad, Kishore Chandra

2013-01-01

83

The vertical occipital fasciculus: a century of controversy resolved by in vivo measurements.  

PubMed

The vertical occipital fasciculus (VOF) is the only major fiber bundle connecting dorsolateral and ventrolateral visual cortex. Only a handful of studies have examined the anatomy of the VOF or its role in cognition in the living human brain. Here, we trace the contentious history of the VOF, beginning with its original discovery in monkey by Wernicke (1881) and in human by Obersteiner (1888), to its disappearance from the literature, and recent reemergence a century later. We introduce an algorithm to identify the VOF in vivo using diffusion-weighted imaging and tractography, and show that the VOF can be found in every hemisphere (n = 74). Quantitative T1 measurements demonstrate that tissue properties, such as myelination, in the VOF differ from neighboring white-matter tracts. The terminations of the VOF are in consistent positions relative to cortical folding patterns in the dorsal and ventral visual streams. Recent findings demonstrate that these same anatomical locations also mark cytoarchitectonic and functional transitions in dorsal and ventral visual cortex. We conclude that the VOF is likely to serve a unique role in the communication of signals between regions on the ventral surface that are important for the perception of visual categories (e.g., words, faces, bodies, etc.) and regions on the dorsal surface involved in the control of eye movements, attention, and motion perception. PMID:25404310

Yeatman, Jason D; Weiner, Kevin S; Pestilli, Franco; Rokem, Ariel; Mezer, Aviv; Wandell, Brian A

2014-12-01

84

Refractory headaches treated with bilateral occipital and temporal region stimulation  

PubMed Central

Objectives To describe use of bilateral temporal and occipital stimulator leads for a refractory headache disorder. Materials and methods A 31-year-old female had a 10-year history of chronic, severe occipital and temporal region headaches. The patient underwent permanent implant of an occipital stimulator system that resulted in sustained, compete resolution of her occipital pain. However, she continued to suffer disabling (10/10) temporal region headaches and was bedbound most days of the week. Therefore, bilateral temporal stimulator leads were implanted and tunneled to her internal pulse generator. Results At 12-month follow-up, the patient enjoyed sustained improvement in her pain scores (8/10) and marked increase in her level of functioning. Taking into account increased activity level, she rated her overall improvement at 50%. Unfortunately, infection and erosion of her right temporal lead necessitated temporal stimulator removal. Conclusion Headache disorders may require stimulation of all painful cephalic regions. However, our success in this case must be considered in light of the technical challenges and expense of placing stimulator leads subcutaneously around the head and neck, including the risk of infection, lead breakage, erosion, and migration. PMID:24707189

Zach, Kelly J; Trentman, Terrence L; Zimmerman, Richard S; Dodick, David W

2014-01-01

85

Traumatic atlanto-occipital dislocation: a case report.  

PubMed

We report a 30-year-old man with atlanto-occipital dislocation after a traffic accident. Diagnosis was based on radiography, computed tomography, and magnetic resonance imaging. Owing to the critical conditions that did not fulfil advanced trauma and life support protocols, surgical treatment was deferred, and the patient died 10 hours later. PMID:23255654

Munoz-Mahamud, Ernesto; Combalia, Andres; Bori, Guillem

2012-12-01

86

RESEARCH REPORT Occipital gamma activation during Vipassana meditation  

E-print Network

RESEARCH REPORT Occipital gamma activation during Vipassana meditation B. Rael Cahn · Arnaud Long-term Vipassana meditators sat in medi- tation vs. a control rest (mind-wandering) state for 21 min in a counterbalanced design with spontaneous EEG recor- ded. Meditation state dynamics were measured with spec- tral

87

RESEARCH REPORT Occipital gamma activation during Vipassana meditation  

E-print Network

RESEARCH REPORT Occipital gamma activation during Vipassana meditation B. Rael Cahn · Arnaud. This article is published with open access at Springerlink.com Abstract Long-term Vipassana meditators sat with spontaneous EEG recor- ded. Meditation state dynamics were measured with spec- tral decomposition of the last

Delorme, Arnaud

88

Benign Occipital Epilepsies of Childhood: Clinical Features and Genetics  

ERIC Educational Resources Information Center

The early and late benign occipital epilepsies of childhood (BOEC) are described as two discrete electro-clinical syndromes, eponymously known as Panayiotopoulos and Gastaut syndromes. Our aim was to explore the clinical features, classification and clinical genetics of these syndromes using twin and multiplex family studies to determine whether…

Taylor, Isabella; Berkovic, Samuel F.; Kivity, Sara; Scheffer, Ingrid E.

2008-01-01

89

Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain  

Microsoft Academic Search

BACKGROUND: The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected. RESULTS: Using microarrays and quantitative PCR, the mRNA expression profiles of these two neuroanatomical regions were compared in postmortem brain tissue from RTT patients and normal controls. A subset of genes was differentially expressed

Joanne H Gibson; Barry Slobedman; Harikrishnan KN; Sarah L Williamson; Dimitri Minchenko; Assam El-Osta; Joshua L Stern; John Christodoulou

2010-01-01

90

Expression of long non-coding RNA LOC285194 and its prognostic significance in human pancreatic ductal adenocarcinoma  

PubMed Central

Introduction: Dysregulation of long non-coding RNAs (lncRNAs) plays critical roles in tumor progression. lncRNA LOC285194 was previously shown to be correlated with aggressive clinicopathological features and poor prognosis in several cancers. The aim of this study was to investigate relationship between LOC285194 expression and clinical outcomes in human pancreatic ductal adenocarcinoma (PDAC). Methods: Quantitative real-time PCR (qRT-PCR) assay was performed to detect the expression of lncRNA LOC285194 in human PDAC cells and tissue samples. The association of LOC285194 expression with clinicopathologic features was analyzed. Kaplan-Meier analyses were used to assess survival of patients. Univariate and multivariate analyses were performed using the Cox proportional hazards model to analyze the prognostic significance of LOC285194 expression. Results: Our data showed that the relative level of LOC285194 in PDAC cells was significantly lower than that in normal human pancreatic duct epithelial cell line. Also, the expression of LOC285194 in PDAC tissues was significantly lower than that in adjacent non-tumor tissues. By statistical analyses, low LOC285194 expression was observed to be closely correlated with clinical stage, lymphnode metastasis and liver metastasis. Kaplan-Meier survival analysis revealed that patients with low LOC285194 expression had a poor overall survival compared with the high LOC285194 group (P < 0.05). Univariate and multivariate analyses showed that low LOC285194 expression was an independent poor prognostic factor for PDAC patients. Conclusions: Our data provided the first evidence that reduced LOC285194 in PDAC tissues was correlated with tumor progression, and lncRNA LOC285194 might be a potential molecular biomarker for predicting the prognosis of patients. PMID:25550852

Ding, Yue-Chao; Yu, Wei; Ma, Chao; Wang, Qian; Huang, Chang-Shan; Huang, Tao

2014-01-01

91

Rapid and Reversible Recruitment of Early Visual Cortex for Touch  

Microsoft Academic Search

BackgroundThe loss of vision has been associated with enhanced performance in non-visual tasks such as tactile discrimination and sound localization. Current evidence suggests that these functional gains are linked to the recruitment of the occipital visual cortex for non-visual processing, but the neurophysiological mechanisms underlying these crossmodal changes remain uncertain. One possible explanation is that visual deprivation is associated with

Lotfi B. Merabet; Roy Hamilton; Gottfried Schlaug; Jascha D. Swisher; Elaine T. Kiriakopoulos; Naomi B. Pitskel; Thomas Kauffman; Alvaro Pascual-Leone; David C. Burr

2008-01-01

92

Language Networks in Anophthalmia: Maintained Hierarchy of Processing in "Visual" Cortex  

ERIC Educational Resources Information Center

Imaging studies in blind subjects have consistently shown that sensory and cognitive tasks evoke activity in the occipital cortex, which is normally visual. The precise areas involved and degree of activation are dependent upon the cause and age of onset of blindness. Here, we investigated the cortical language network at rest and during an…

Watkins, Kate E.; Cowey, Alan; Alexander, Iona; Filippini, Nicola; Kennedy, James M.; Smith, Stephen M.; Ragge, Nicola; Bridge, Holly

2012-01-01

93

The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding  

PubMed Central

The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas. PMID:24032005

Ribeiro, Pedro F. M.; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T.; Farfel, José M.; Ferretti-Rebustini, Renata E. L.; Leite, Renata E. P.; Filho, Wilson J.; Herculano-Houzel, Suzana

2013-01-01

94

The Involvement of Occipital and Inferior Frontal Cortex in the Phonological Learning of Chinese Characters  

ERIC Educational Resources Information Center

Neural changes related to the learning of the pronunciation of Chinese characters in English speakers were examined using fMRI. We examined the item-specific learning effects for trained characters and the generalization of phonetic knowledge to novel transfer characters that shared a phonetic radical (part of a character that gives a clue to the…

Deng, Yuan; Chou, Tai-li; Ding, Guo-sheng; Peng, Dan-ling; Booth, James R.

2011-01-01

95

Generators of visual evoked potentials investigated by dipole tracing in the human occipital cortex  

Microsoft Academic Search

Current source generators (dipoles) of the human visual evoked potentials to pattern-onset stimuli were investigated with the dipole tracing method, using a realistic four-layer head model of scalp-skull-fluid-brain, which can equate the surface potential distributions on a scalp to one or two corresponding equivalent dipoles. Three healthy adult human subjects were used, and 29 electrodes were set on a scalp

H Ikeda; H Nishijo; K Miyamoto; R Tamura; S Endo; T Ono

1998-01-01

96

Recessive LAMC3 mutations cause malformations of occipital cortical development  

PubMed Central

The biological basis for regional and inter-species differences in cerebral cortical morphology is poorly understood. We focused on consanguineous Turkish families with a single affected member with complex bilateral occipital cortical gyration abnormalities. By using whole-exome sequencing, we initially identified a homozygous 2-bp deletion in LAMC3, the laminin ?3 gene, leading to an immediate premature termination codon. In two other affected individuals with nearly identical phenotypes, we identified a homozygous nonsense mutation and a compound heterozygous mutation. In human but not mouse fetal brain, LAMC3 is enriched in postmitotic cortical plate neurons, localizing primarily to the somatodendritic compartment. LAMC3 expression peaks between late gestation and late infancy, paralleling the expression of molecules that are important in dendritogenesis and synapse formation. The discovery of the molecular basis of this unusual occipital malformation furthers our understanding of the complex biology underlying the formation of cortical gyrations. PMID:21572413

Barak, Tanyeri; Kwan, Kenneth Y; Louvi, Angeliki; Demirbilek, Veysi; Sayg?, Serap; Tüysüz, Beyhan; Choi, Murim; Boyac?, Hüseyin; Doerschner, Katja; Zhu, Ying; Kaymakçalan, Hande; Y?lmaz, Saliha; Bak?rc?o?lu, Mehmet; Ça?layan, Ahmet Okay; Öztürk, Ali Kemal; Yasuno, Katsuhito; Brunken, William J; Atalar, Ergin; Yalç?nkaya, Cengiz; Dinçer, Alp; Bronen, Richard A; Mane, Shrikant; Özçelik, Tayfun; Lifton, Richard P; Šestan, Nenad; Bilgüvar, Kaya; Günel, Murat

2012-01-01

97

Cervical Facet Arthropathy and Occipital Neuralgia: Headache Culprits  

Microsoft Academic Search

Cervicogenic headache (CH) is pain referred from the neck. Two common causes are cervical facet arthropathy and occipital\\u000a neuralgia. Clinical diagnosis is difficult because of the overlying features between primary headaches such as migraine, tension-type\\u000a headache, and CH. Interventional pain physicians have focused on supporting the clinical diagnosis of CH with confirmatory\\u000a blocks. The treatment of cervical facet arthropathy as

J. D. Hoppenfeld

2010-01-01

98

Frontal terminations for the inferior fronto-occipital fascicle: anatomical dissection, DTI study and functional considerations on a multi-component bundle.  

PubMed

The anatomy and functional role of the inferior fronto-occipital fascicle (IFOF) remain poorly known. We accurately analyze its course and the anatomical distribution of its frontal terminations. We propose a classification of the IFOF in different subcomponents. Ten hemispheres (5 left, 5 right) were dissected with Klingler's technique. In addition to the IFOF dissection, we performed a 4-T diffusion tensor imaging study on a single healthy subject. We identified two layers of IFOF. The first one is superficial and antero-superiorly directed, terminating in the inferior frontal gyrus. The second is deeper and consists of three portions: posterior, middle and anterior. The posterior component terminates in the middle frontal gyrus (MFG) and dorso-lateral prefrontal cortex. The middle component terminates in the MFG and lateral orbito-frontal cortex. The anterior one is directed to the orbito-frontal cortex and frontal pole. In vivo tractography study confirmed these anatomical findings. We suggest that the distribution of IFOF fibers within the frontal lobe corresponds to a fine functional segmentation. IFOF can be considered as a "multi-function" bundle, with each anatomical subcomponent subserving different brain processing. The superficial layer and the posterior component of the deep layer, which connects the occipital extrastriate, temporo-basal and inferior frontal cortices, might subserve semantic processing. The middle component of the deep layer could play a role in a multimodal sensory-motor integration. Finally, the anterior component of the deep layer might be involved in emotional and behavioral aspects. PMID:22200882

Sarubbo, Silvio; De Benedictis, Alessandro; Maldonado, Igor L; Basso, Gianpaolo; Duffau, Hugues

2013-01-01

99

Analysis of a novel human gene, LOC92912, over-expressed in hypopharyngeal tumours.  

PubMed

We have identified by differential display a number of novel genes that are expressed in hypopharyngeal head and neck squamous cell carcinoma. We report here the characterisation of one of these novel human genes, LOC92912, that encodes a protein of 375 amino acids. The protein contains a RWD domain, a coiled-coil, and an E2 ubiquitin conjugating enzyme domain. LOC92912 is upregulated in about 85% of tumour samples. It is expressed in tumour masses and in invasive epithelium, and is located in the cytoplasm of cells. To gain insights into its functions, we identified potential interacting partners by immunoaffinity purification of the flag tagged protein followed by MALDI peptide mass fingerprinting mass spectrometry. Actin and six actin-binding proteins were unambiguously identified as potential interacting partners, suggesting that LOC92912's functions may be linked with the cytoskeleton. This novel human gene may represent a new target for cancer therapeutics. PMID:16300736

Seghatoleslam, Atefeh; Zambrano, Alberto; Millon, Regine; Ganguli, Gitali; Argentini, Manuela; Cromer, Anne; Abecassis, Joseph; Wasylyk, Bohdan

2006-01-01

100

Peritrigonal and temporo-occipital heterotopia with corpus callosum and cerebellar dysgenesis  

PubMed Central

Objective: To describe a homogeneous subtype of periventricular nodular heterotopia (PNH) as part of a newly defined malformation complex. Methods: Observational study including review of brain MRI and clinical findings of a cohort of 50 patients with PNH in the temporo-occipital horns and trigones, mutation analysis of the FLNA gene, and anatomopathologic study of a fetal brain. Results: There were 28 females and 22 males. All were sporadic with the exception of an affected mother and son. Epilepsy occurred in 62%, cerebellar signs in 56%, cognitive impairment in 56%, and autism in 12%. Seventy percent were referred within the 3rd year of life. Imaging revealed a normal cerebral cortex in 76% and abnormal cortical folding in 24%. In all patients the hippocampi were under-rotated and in 10% they merged with the heterotopia. Cerebellar dysgenesis was observed in 84% and a hypoplastic corpus callosum in 60%. There was no gender bias or uneven gender distribution of clinical and anatomic severity. No mutations of FLNA occurred in 33 individuals examined. Heterotopia in the fetal brain revealed cytoarchitectonic characteristics similar to those associated with FLNA mutations; cortical pathology was not typical of polymicrogyria. Cerebellar involvement was more severe and the hippocampi appeared simple and under-rotated. Conclusions: This series delineates a malformation complex in which PNH in the trigones and occipito-temporal horns is associated with hippocampal, corpus callosum, and cerebellar dysgenesis. This subtype of PNH is distinct from classic PNH caused by FLNA mutations. PMID:22914838

Pisano, Tiziana; Barkovich, A. James; Leventer, Richard J.; Squier, Waney; Scheffer, Ingrid E.; Parrini, Elena; Blaser, Susan; Marini, Carla; Robertson, Stephen; Tortorella, Gaetano; Rosenow, Felix; Thomas, Pierre; McGillivray, George; Andermann, Eva; Andermann, Frederick; Berkovic, Samuel F.; Dobyns, William B.

2012-01-01

101

Occipital and orbitofrontal hemodynamics during naturally paced reading: an fNIRS study.  

PubMed

Humans typically read at incredibly fast rates, because they predict likely occurring words from a given context. Here, we used functional near-infrared spectroscopy (fNIRS) to track the ultra-rapid hemodynamic responses of words presented every 280 ms in a naturally paced sentence context. We found a lower occipital deoxygenation to unpredictable than to predictable words. The greater hemodynamic responses to unexpected words suggest that the visual features of expected words have been pre-activated previous to stimulus presentation. Second, we tested opposing theoretical proposals about the role of the medial orbitofrontal cortex (OFC): Either OFC may respond to the breach of expectation; or OFC is activated when the present stimulus matches the prediction. A significant interaction between word frequency and predictability indicated OFC responses to breaches of expectation for low- but not for high-frequency words: OFC is sensitive to both, bottom-up processing as mediated by word frequency, as well as top-down predictions. Particularly, when a rare word is unpredictable, OFC becomes active. Finally, we discuss how a high temporal resolution can help future studies to disentangle the hemodynamic responses of single trials in such an ultra-rapid event succession as naturally paced reading. PMID:24642288

Hofmann, Markus J; Dambacher, Michael; Jacobs, Arthur M; Kliegl, Reinhold; Radach, Ralph; Kuchinke, Lars; Plichta, Michael M; Fallgatter, Andreas J; Herrmann, Martin J

2014-07-01

102

Credit Card Misuse, Money Attitudes, and Compulsive Buying Behaviors: A Comparison of Internal and External Locus of Control (LOC) Consumers  

ERIC Educational Resources Information Center

This study examined attitudinal and behavioral differences between internal and external locus of control (LOC) consumers on credit card misuse, the importance of money, and compulsive buying. Using multiple analysis of variance and separate analyses of variance, internal LOC consumers were found to have lower scores on credit card misuse and…

Watson, Stevie

2009-01-01

103

Survivor of a traumatic atlanto-occipital dislocation.  

PubMed

Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition. We report a rare case of atlanto-occipital dislocation (AOD) in a surviving patient with more than one-year follow-up. The mechanism of injury appears to be an extreme hyperextension applied to the head. This injury occurs more frequently in children since they are anatomically predisposed (flat articulation between the occiput and the atlas, increased ligamentous laxity). The diagnosis should be suggested by severe neurological injury after high trauma but also post-traumatic cardiorespiratory deficit. There have been reports of atlanto-occipital dilocations without neurologic impairment. A radiographic examination must be performed and lateral cervical radiographs should be acquired. However, additional imaging with CT or MRI may be required to aid diagnosis of AOD in cases in which radiographic findings are equivocal. Once the diagnosis of AOD has been confirmed, an anatomical classification should be made according to the magnitude of displacement. Fatal lesions are of neurological and vascular origin and some authors advocate the systematic use of angiography. Consensus regarding the management of AOD in adults has been achieved. Occipito-cervical arthrodesis is the recommended treatment option. We advocate a two-stage surgery: the patient is initially fitted with a halo vest then occipitocervical fusion is performed. Surgical treatment should be combined with cardiorespiratory management. The emergency teams should get familiar with this injury since they will be increasingly confronted to it. Early recognition and standard appropriate management is essential to avoid delayed treatment and complications. PMID:21273154

Ehlinger, M; Charles, Y-P; Adam, P; Bierry, G; Dosch, J-C; Steib, J-P; Bonnomet, F

2011-05-01

104

Occipital Neuralgia after Hair Transplantation and Its Treatment  

PubMed Central

While undergoing full thickness tissue harvest from the posterior scalp, a 72-year-old man experienced immediate severe pain in the right occiput and was unable to complete the procedure. The pain was constant “sharp” and “shocking” with numbness in the distribution of the lesser occipital nerve, exacerbated by physical activity, and local anesthetic blocks provided temporary complete relief. After numerous treatments over several years, including oral analgesics, botulinum toxin injections, and acupuncture, proved ineffective, pulsed radiofrequency neuromodulation provided greater than 80% relief for 5 months. PMID:25688308

Siefferman, Jason; Khelemsky, Yury

2015-01-01

105

Occipital neuralgia after hair transplantation and its treatment.  

PubMed

While undergoing full thickness tissue harvest from the posterior scalp, a 72-year-old man experienced immediate severe pain in the right occiput and was unable to complete the procedure. The pain was constant "sharp" and "shocking" with numbness in the distribution of the lesser occipital nerve, exacerbated by physical activity, and local anesthetic blocks provided temporary complete relief. After numerous treatments over several years, including oral analgesics, botulinum toxin injections, and acupuncture, proved ineffective, pulsed radiofrequency neuromodulation provided greater than 80% relief for 5 months. PMID:25688308

Siefferman, Jason; Khelemsky, Yury

2015-01-01

106

PAPER www.rsc.org/loc | Lab on a Chip Laser-induced cavitation based micropump  

E-print Network

of cavitation in microfluidics, for example in microfluidic phase- change heat-exchangers.6 Yet, in the authorsPAPER www.rsc.org/loc | Lab on a Chip Laser-induced cavitation based micropump Rory Dijkinka as versatile and robust pumping techniques. Here, we present a cavitation based technique, which is able

Ohl, Claus-Dieter

107

UnLocIn: Unauthorized Location Inference on Smartphones without Being Caught  

E-print Network

UnLocIn: Unauthorized Location Inference on Smartphones without Being Caught Le Nguyen, Yuan Tian of the critical issues in the smartphone era. Since users carry their phones everywhere and all the time, leaking idea and show that clever attackers can do so without being detected by current malware detection

Tague, Patrick

108

Occipital condyle fractures: incidence and clinical follow-up at a level 1 trauma centre  

Microsoft Academic Search

The purpose of the study was to investigate the incidence, management, and outcomes of occipital condyle fractures at a level\\u000a 1 trauma center. Blunt trauma patients with occipital condyle fracture admitted to a level 1 trauma center over a 3-year period\\u000a were identified. Prospective clinical and functional follow-up was undertaken, including further radiographic imaging. The\\u000a incidence of occipital condyle fracture

Gregory M. Malham; Helen M. Ackland; Rachel Jones; Owen D. Williamson; Dinesh K. Varma

2009-01-01

109

Differential Sensitivity of Human Visual Cortex to Faces, Letterstrings, and Textures: A Functional Magnetic Resonance Imaging Study  

Microsoft Academic Search

Twelve normal subjects viewed alternating sequences of unfa- miliar faces, unpronounceable nonword letterstrings, and tex- tures while echoplanar functional magnetic resonance images were acquired in seven slices extending from the posterior margin of the splenium to near the occipital pole. These stimuli were chosen to elicit initial category-specific processing in extrastriate cortex while minimizing semantic processing. Over- all, faces evoked

Aina Puce; Truett Allison; Maryam Asgari; John C. Gore; Gregory McCarthy

1996-01-01

110

The Intramuscular Course of the Greater Occipital Nerve: Novel Findings with Potential Implications for Operative Interventions and Occipital Neuralgia  

PubMed Central

Background: A better understanding of the etiologies of occipital neuralgia would help the clinician treat patients with this debilitating condition. Since few studies have examined the muscular course of the greater occipital nerve (GON), this study was performed. Methods: Thirty adult cadaveric sides underwent dissection of the posterior occiput with special attention to the intramuscular course of the GON. Nerves were typed based on their muscular course. Results: The GON traveled through the trapezius (type I; n = 5, 16.7%) or its aponeurosis (type II; n = 15, 83.3%) to become subcutaneous. Variations in the subtrapezius muscular course were found in 10 (33%) sides. In two (6.7%) sides, the GON traveled through the lower edge of the inferior capitis oblique muscle (subtype a). On five (16.7%) sides, the GON coursed through a tendinous band of the semispinalis capitis, not through its muscular fibers (subtype b). On three (10%) sides the GON bypassed the semispinalis capitis muscle to travel between its most medial fibers and the nuchal ligament (subtype c). For subtypes, eight were type II courses (through the aponeurosis of the trapezius), and two were type I courses (through the trapezius muscle). The authors identified two type IIa courses, four type IIb courses, and two type IIc courses. Type I courses included one type Ib and one type Ic courses. Conclusions: Variations in the muscular course of the GON were common. Future studies correlating these findings with the anatomy in patients with occipital neuralgia may elucidate nerve courses vulnerable to nerve compression. This enhanced classification scheme describes the morphology in this region and allows more specific communications about GON variations. PMID:25422783

Tubbs, R. Shane; Watanabe, Koichi; Loukas, Marios; Cohen-Gadol, Aaron A.

2014-01-01

111

Two-layer Lab-on-a-chip (LOC) with passive capillary valves for mHealth medical diagnostics.  

PubMed

There is a new potential to address needs for medical diagnostics in Point-of-Care (PoC) applications using mHealth (Mobile computing, medical sensors, and communications technologies for health care), a mHealth based lab test will require a LOC to perform clinical analysis. In this work, we describe the design of a simple Lab-on-a-chip (LOC) platform for mHealth medical diagnostics. The LOC utilizes a passive capillary valve with no moving parts for fluid control using channels with very low aspect ratios cross sections (i.e., channel width???height) achieved through transitions in the channel geometry via that arrest capillary flow. Using a CO2 laser in raster engraving mode, we have designed and fabricated an eight-channel LOC for fluorescence signal detection fabricated by engraving and combining just two polymer layers. Each of the LOC channels is capable of mixing two reagents (e.g., enzyme and substrate) for various assays. For mHealth detection, we used a mobile CCD detector equipped with LED multispectral illumination in the red, green, blue, and white range. This technology enables the development of low-cost LOC platforms for mHealth whose fabrication is compatible with standard industrial plastic fabrication processes to enable mass production of mHealth diagnostic devices, which may broaden the use of LOCs in PoC applications, especially in global health settings. PMID:25626544

Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

2015-01-01

112

Linear aspects of transformation from interictal epileptic discharges to BOLD fMRI signals in an animal model of occipital epilepsy.  

PubMed

Epileptic disorders manifest with seizures and interictal epileptic discharges (IEDs). The hemodynamic changes that accompany IEDs are poorly understood and may be critical for understanding epileptogenesis. Despite a known linear coupling of the neurovascular elements in normal brain tissues, previous simultaneous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) studies have shown variable correlations between epileptic discharges and blood oxygenation level-dependent (BOLD) response, partly because most previous studies assumed particular hemodynamic properties in normal brain tissue. The occurrence of IEDs in human subjects is unpredictable. Therefore, an animal model with reproducible stereotyped IEDs was developed by the focal injection of penicillin into the right occipital cortex of rats anesthetized with isoflurane. Simultaneous EEG-fMRI was used to study the hemodynamic changes during IEDs. A hybrid of temporal independent component analysis (ICA) of EEG and spatial ICA of fMRI data was used to correlate BOLD fMRI signals with IEDs. A linear autoregression with exogenous input (ARX) model was used to estimate the hemodynamic impulse response function (HIRF) based on the data from simultaneous EEG-fMRI measurement. Changes in the measured BOLD signal from the right primary visual cortex and bilateral visual association cortices were consistently coupled to IEDs. The linear ARX model was applied here to confirm that a linear transform can be used to study the correlation between BOLD signal and its corresponding neural activity in this animal model of occipital epilepsy. PMID:16414283

Mirsattari, Seyed M; Wang, Zheng; Ives, John R; Bihari, Frank; Leung, L Stan; Bartha, Robert; Menon, Ravi S

2006-05-01

113

Indications and Outcomes for Surgical Treatment of Patients with Chronic Migraine Headaches Caused by Occipital Neuralgia  

Microsoft Academic Search

Washington, D.C. Background: Occipital neuralgia is a headache syndrome characterized by par- oxysmal headaches localizing to the posterior scalp. The critical diagnostic feature is symptomatic response to local anesthetic blockade of the greater or lesser occipital nerve. Further characterization is debated in the literature re- garding the diagnosis and optimal management of this condition. The authors present the largest reported

Ivica Ducic; Emily C. Hartmann; Ethan E. Larson

2009-01-01

114

Fixation-off Sensitivity in Idiopathic Childhood Occipital Epilepsy of Gastaut.  

PubMed

A 7-year-old boy presented with episodic blindness for the last 2 months with occipital paroxysms and fixation-off sensitivity on electroencephalography (EEG). The clinico-EEG features were suggestive of idiopathic childhood occipital epilepsy of Gastaut. The interesting phenomenon of fixation-off sensitivity is discussed. PMID:24810088

Jain, Puneet; Sharma, Suvasini; Patra, Bijoy; Aneja, Satinder

2015-04-01

115

Occipital seizures and subcortical T2 hypointensity in the setting of hyperglycemia  

PubMed Central

Introduction Occipital lobe seizures are a recognized manifestation of diabetic nonketotic hyperglycemia, though not as common as focal motor seizures. Occipital lobe white matter T2 hypointensity may suggest this diagnosis. Methods We present a case of a 66-year-old man with hyperglycemia-related occipital lobe seizures who presented with confusion, intermittent visual hallucinations, and homonymous hemianopia. Results Magnetic resonance imaging showed subcortical T2 hypointensity within the left occipital lobe with adjacent leptomeningeal enhancement. These findings were transient with disappearance in a follow-up MRI. The EEG captured frequent seizures originating in the left occipital region. HbA1c level was 13.4% on presentation, and finger stick blood glucose level was 400 mg/dl. Conclusion Hyperglycemia should be considered in the etiology of differential diagnosis of patients with visual abnormalities suspicious for seizures, especially when the MRI shows focal subcortical T2 hypointensity with or without leptomeningeal enhancement. PMID:25667880

Putta, Swapna L.; Weisholtz, Daniel; Milligan, Tracey A.

2014-01-01

116

The human cerebral cortex flattens during adolescence.  

PubMed

The human cerebral cortex appears to shrink during adolescence. To delineate the dynamic morphological changes involved in this process, 52 healthy male and female adolescents (11-17 years old) were neuroimaged twice using magnetic resonance imaging, approximately 2 years apart. Using a novel morphometric analysis procedure combining the FreeSurfer and BrainVisa image software suites, we quantified global and lobar change in cortical thickness, outer surface area, the gyrification index, the average Euclidean distance between opposing sides of the white matter surface (gyral white matter thickness), the convex ("exposed") part of the outer cortical surface (hull surface area), sulcal length, depth, and width. We found that the cortical surface flattens during adolescence. Flattening was strongest in the frontal and occipital cortices, in which significant sulcal widening and decreased sulcal depth co-occurred. Globally, sulcal widening was associated with cortical thinning and, for the frontal cortex, with loss of surface area. For the other cortical lobes, thinning was related to gyral white matter expansion. The overall flattening of the macrostructural three-dimensional architecture of the human cortex during adolescence thus involves changes in gray matter and effects of the maturation of white matter. PMID:24048830

Alemán-Gómez, Yasser; Janssen, Joost; Schnack, Hugo; Balaban, Evan; Pina-Camacho, Laura; Alfaro-Almagro, Fidel; Castro-Fornieles, Josefina; Otero, Soraya; Baeza, Immaculada; Moreno, Dolores; Bargalló, Nuria; Parellada, Mara; Arango, Celso; Desco, Manuel

2013-09-18

117

Global-scale multiple-event location and travel-time analysis using BayesLoc  

Microsoft Academic Search

We have constructed a global-scale seismic arrival-time data set that consists of over 3.5 million arrivals from over 13 thousands events, with arrivals from multiple phases. The data set was constructed to yield about 1 degree spacing between well recorded events at multiple depth levels. We analyze the data set using BayesLoc, a Bayesian multiple-event locator, which simultaneously provides a

G. Johannesson; S. C. Myers

2010-01-01

118

Sensitivity to syntax in visual cortex  

PubMed Central

One of the most intriguing findings on language comprehension is that violations of syntactic predictions can affect event-related potentials as early as 120 ms, in the same time-window as early sensory processing. This effect, the so-called early left-anterior negativity (ELAN), has been argued to reflect word category access and initial syntactic structure building (Friederici, 2002). In two experiments, we used magnetoencephalography to investigate whether (a) rapid word category identification relies on overt category-marking closed-class morphemes and (b) whether violations of word category predictions affect modality-specific sensory responses. Participants read sentences containing violations of word category predictions. Unexpected items varied in whether or not their word category was marked by an overt function morpheme. In Experiment 1, the amplitude of the visual evoked M100 component was increased for unexpected items, but only when word category was overtly marked by a function morpheme. Dipole modeling localized the generator of this effect to the occipital cortex. Experiment 2 replicated the main results of Experiment 1 and eliminated two non-morphology-related explanations of the M100 contrast we observed between targets containing overt category-marking and targets that lacked such morphology. Our results show that during reading, syntactically relevant cues in the input can affect activity in occipital regions at around 125 ms, a finding that may shed new light on the remarkable rapidity of language processing. PMID:19121826

Dikker, Suzanne; Rabagliati, Hugh; Pylkkänen, Liina

2009-01-01

119

dLocAuth: a dynamic multifactor authentication scheme for mCommerce applications using independent location-based obfuscation  

NASA Astrophysics Data System (ADS)

This paper proposes a new technique to obfuscate an authentication-challenge program (named LocProg) using randomly generated data together with a client's current location in real-time. LocProg can be used to enable any handsetapplication on mobile-devices (e.g. mCommerce on Smartphones) that requires authentication with a remote authenticator (e.g. bank). The motivation of this novel technique is to a) enhance the security against replay attacks, which is currently based on using real-time nonce(s), and b) add a new security factor, which is location verified by two independent sources, to challenge / response methods for authentication. To assure a secure-live transaction, thus reducing the possibility of replay and other remote attacks, the authors have devised a novel technique to obtain the client's location from two independent sources of GPS on the client's side and the cellular network on authenticator's side. The algorithm of LocProg is based on obfuscating "random elements plus a client's data" with a location-based key, generated on the bank side. LocProg is then sent to the client and is designed so it will automatically integrate into the target application on the client's handset. The client can then de-obfuscate LocProg if s/he is within a certain range around the location calculated by the bank and if the correct personal data is supplied. LocProg also has features to protect against trial/error attacks. Analysis of LocAuth's security (trust, threat and system models) and trials based on a prototype implementation (on Android platform) prove the viability and novelty of LocAuth.

Kuseler, Torben; Lami, Ihsan A.

2012-06-01

120

Differential Contribution of Right and Left Temporo-Occipital and Anterior Temporal Lesions to Face Recognition Disorders  

PubMed Central

In the study of prosopagnosia, several issues (such as the specific or non-specific manifestations of prosopagnosia, the unitary or non-unitary nature of this syndrome and the mechanisms underlying face recognition disorders) are still controversial. Two main sources of variance partially accounting for these controversies could be the qualitative differences between the face recognition disorders observed in patients with prevalent lesions of the right or left hemisphere and in those with lesions encroaching upon the temporo-occipital (TO) or the (right) anterior temporal cortex. Results of our review seem to confirm these suggestions. Indeed, they show that (a) the most specific forms of prosopagnosia are due to lesions of a right posterior network including the occipital face area and the fusiform face area, whereas (b) the face identification defects observed in patients with left TO lesions seem due to a semantic defect impeding access to person-specific semantic information from the visual modality. Furthermore, face recognition defects resulting from right anterior temporal lesions can usually be considered as part of a multimodal people recognition disorder. The implications of our review are, therefore, the following: (1) to consider the components of visual agnosia often observed in prosopagnosic patients with bilateral TO lesions as part of a semantic defect, resulting from left-sided lesions (and not from prosopagnosia proper); (2) to systematically investigate voice recognition disorders in patients with right anterior temporal lesions to determine whether the face recognition defect should be considered a form of “associative prosopagnosia” or a form of the “multimodal people recognition disorder.” PMID:21687793

Gainotti, Guido; Marra, Camillo

2011-01-01

121

Facial expression recognition takes longer in the posterior superior temporal sulcus than in the occipital face area.  

PubMed

Neuroimaging studies have identified a face-selective region in the right posterior superior temporal sulcus (rpSTS) that responds more strongly during facial expression recognition tasks than during facial identity recognition tasks, but precisely when the rpSTS begins to causally contribute to expression recognition is unclear. The present study addressed this issue using transcranial magnetic stimulation (TMS). In Experiment 1, repetitive TMS delivered over the rpSTS of human participants, at a frequency of 10 Hz for 500 ms, selectively impaired a facial expression task but had no effect on a matched facial identity task. In Experiment 2, participants performed the expression task only while double-pulse TMS (dTMS) was delivered over the rpSTS or over the right occipital face area (rOFA), a face-selective region in lateral occipital cortex, at different latencies up to 210 ms after stimulus onset. Task performance was selectively impaired when dTMS was delivered over the rpSTS at 60-100 ms and 100-140 ms. dTMS delivered over the rOFA impaired task performance at 60-100 ms only. These results demonstrate that the rpSTS causally contributes to expression recognition and that it does so over a longer time-scale than the rOFA. This difference in the length of the TMS induced impairment between the rpSTS and the rOFA suggests that the neural computations that contribute to facial expression recognition in each region are functionally distinct. PMID:24990937

Pitcher, David

2014-07-01

122

LocZ Is a New Cell Division Protein Involved in Proper Septum Placement in Streptococcus pneumoniae  

PubMed Central

ABSTRACT How bacteria control proper septum placement at midcell, to guarantee the generation of identical daughter cells, is still largely unknown. Although different systems involved in the selection of the division site have been described in selected species, these do not appear to be widely conserved. Here, we report that LocZ (Spr0334), a newly identified cell division protein, is involved in proper septum placement in Streptococcus pneumoniae. We show that locZ is not essential but that its deletion results in cell division defects and shape deformation, causing cells to divide asymmetrically and generate unequally sized, occasionally anucleated, daughter cells. LocZ has a unique localization profile. It arrives early at midcell, before FtsZ and FtsA, and leaves the septum early, apparently moving along with the equatorial rings that mark the future division sites. Consistently, cells lacking LocZ also show misplacement of the Z-ring, suggesting that it could act as a positive regulator to determine septum placement. LocZ was identified as a substrate of the Ser/Thr protein kinase StkP, which regulates cell division in S. pneumoniae. Interestingly, homologues of LocZ are found only in streptococci, lactococci, and enterococci, indicating that this close phylogenetically related group of bacteria evolved a specific solution to spatially regulate cell division. PMID:25550321

Hole?ková, Nela; Molle, Virginie; Buriánková, Karolína; Benada, Old?ich; Kofro?ová, Olga; Ulrych, Aleš; Branny, Pavel

2014-01-01

123

Reading impairment in an adolescent with temporo-occipital epilepsy. Pre- and post-surgical evaluation.  

PubMed

We present a 16 year-old right-handed case who underwent a left temporo-occipital resection to treat intractable epilepsy. Pre- and post-surgical evaluations showed an average intellectual quotient, preserved abilities in language and visuo-spatial functions and increased reading and spelling deficits (difficulties with irregular words, homophones and phonologically valid spelling errors of irregularly spelled words, associated with preserved performances in non-words). This pattern of characteristic lexical route deficits highlights the major role of the temporo-occipital areas in reading acquisition. We discussed the consequences of temporo-occipital dysfunction on reading. PMID:23116198

Grosmaitre, Catherine; Auclair, Laurent; Dorfmuller, Georg; Leunen, Dorothée; Delalande, Olivier; Folhen, Martine; Bulteau, Christine; Jambaqué, Isabelle

2014-01-01

124

Cervical Myelopathy Secondary to Atlanto-occipital Assimilation: The Usefulness of the Simple Decompressive Surgery  

PubMed Central

Atlanto-occipital assimilation is one of the most common osseous anomalies observed at the craniocervical junction. Most patients with atlas assimilation show no symptom, but some have neurological problems such as myelopathy that may require surgical treatment. Occipitocervical fusion may be required if atlato-occipital assimilation is accompanied by occipito-axial instability. However, in cases of symptomatic atlas assimilation with minor cord compression without instability, simple decompressive surgery may be the treatment modality. This report describes a case of successful treatment of a patient with myelopathy secondary to atlanto-occipital assimilation without instability, using posterior simple decompressive surgery. PMID:24757486

Kim, Kang Rae; Kim, Young Zoon; Cho, Yong Woon; Kim, Joon Soo; Kim, Kyu Hong; Lee, In Chang

2013-01-01

125

Diagnosis and treatment of a chronic atlanto-occipital subluxation in a dog.  

PubMed

A 6-year-old Labrador retriever-cross was evaluated for an abnormal gait and head carriage 6 weeks after suffering trauma. The dog was presented with an ambulatory tetraparesis and was reluctant to move his head. Myelography and computed tomography demonstrated a subluxation of the atlanto-occipital joint with compression of the spinomedullary junction and the brain stem by the occipital bone. Removal of the compressive part of the occipital bone resulted in improvement of the clinical signs within 6 weeks, and resolution of clinical signs occurred 8 months after surgery. PMID:17473025

Rylander, Helena; Robles, Juan Carlos

2007-01-01

126

[Open reduction and dorsal spondylodesis C0-C2 in atlanto-occipital dislocation].  

PubMed

We report the case of a 73-year-old male patient who was suffered trauma after a syncopal fall onto a railway track in the form of an atlanto-occipital dislocation. The diagnostic revealed a bilateral fracture of the occipital condyles coupled with a ventral atlanto-occipital dislocation (Jeanneret type 4) and also an odontoid fracture (Anderson type 2). The patient underwent dorsal spondylodesis of C0-C2 in combination with Magerl's C1-C2 screw fixation. Pre-operatively and postoperatively no neurological abnormalities were found. This rarely occurring and survived traumatological situation is described using the present case as an example. PMID:19557377

John-Puthenveettil, B S; Neff, A; Kröber, M

2009-09-01

127

Frontoparietal cortex controls spatial attention through modulation of anticipatory alpha rhythms.  

PubMed

A dorsal frontoparietal network, including regions in intraparietal sulcus (IPS) and frontal eye field (FEF), has been hypothesized to control the allocation of spatial attention to environmental stimuli. One putative mechanism of control is the desynchronization of electroencephalography (EEG) alpha rhythms (approximately 8-12 Hz) in visual cortex in anticipation of a visual target. We show that brief interference by repetitive transcranial magnetic stimulation (rTMS) with preparatory activity in right IPS or right FEF while subjects attend to a spatial location impairs identification of target visual stimuli approximately 2 s later. This behavioral effect is associated with the disruption of anticipatory (prestimulus) alpha desynchronization and its spatially selective topography in parieto-occipital cortex. Finally, the disruption of anticipatory alpha rhythms in occipital cortex after right IPS- or right FEF-rTMS correlates with deficits of visual identification. These results support the causal role of the dorsal frontoparietal network in the control of visuospatial attention, and suggest that this is partly exerted through the synchronization of occipital visual neurons. PMID:19420253

Capotosto, Paolo; Babiloni, Claudio; Romani, Gian Luca; Corbetta, Maurizio

2009-05-01

128

Occipital condyle fracture with isolated unilateral hypoglossal nerve palsy.  

PubMed

Occipital condyle fractures (OCFs) with selective involvement of the hypoglossal canal are rare. OCFs usually occur after major trauma and combine multiple fractures. We describe a 38-year-old man who presented with neck pain and a tongue deviation to the right side after a traffic accident. Severe limitations were detected during active and passive range of neck motion in all directions. A physical examination revealed a normal gag reflex and normal mobility of the palate, larynx, and shoulder girdle. He had normal taste and general sensation in his tongue. However, he presented with a tongue deviation to the right side on protrusion. A videofluoroscopic swallowing study revealed piecemeal deglutition due to decreased tongue mobility but no aspiration of food. Plain X-ray film findings were negative, but a computed tomography study with coronal reconstruction demonstrated a right OCF involving the hypoglossal canal. An electrodiagnostic study revealed evidence of right hypoglossal nerve palsy. We report a rare case of isolated hypoglossal nerve palsy caused by an OCF. PMID:25379499

Yoon, Jin Won; Lim, Oh Kyung; Park, Ki Deok; Lee, Ju Kang

2014-10-01

129

Occipital Condyle Fracture With Isolated Unilateral Hypoglossal Nerve Palsy  

PubMed Central

Occipital condyle fractures (OCFs) with selective involvement of the hypoglossal canal are rare. OCFs usually occur after major trauma and combine multiple fractures. We describe a 38-year-old man who presented with neck pain and a tongue deviation to the right side after a traffic accident. Severe limitations were detected during active and passive range of neck motion in all directions. A physical examination revealed a normal gag reflex and normal mobility of the palate, larynx, and shoulder girdle. He had normal taste and general sensation in his tongue. However, he presented with a tongue deviation to the right side on protrusion. A videofluoroscopic swallowing study revealed piecemeal deglutition due to decreased tongue mobility but no aspiration of food. Plain X-ray film findings were negative, but a computed tomography study with coronal reconstruction demonstrated a right OCF involving the hypoglossal canal. An electrodiagnostic study revealed evidence of right hypoglossal nerve palsy. We report a rare case of isolated hypoglossal nerve palsy caused by an OCF. PMID:25379499

Yoon, Jin Won; Lim, Oh Kyung; Park, Ki Deok

2014-01-01

130

Changes in Cerebral Cortex of Children Treated for Medulloblastoma  

SciTech Connect

Purpose: Children with medulloblastoma undergo surgery, radiotherapy, and chemotherapy. After treatment, these children have numerous structural abnormalities. Using high-resolution magnetic resonance imaging, we measured the thickness of the cerebral cortex in a group of medulloblastoma patients and a group of normally developing children. Methods and Materials: We obtained magnetic resonance imaging scans and measured the cortical thickness in 9 children after treatment of medulloblastoma. The measurements from these children were compared with the measurements from age- and gender-matched normally developing children previously scanned. For additional comparison, the pattern of thickness change was compared with the cortical thickness maps from a larger group of 65 normally developing children. Results: In the left hemisphere, relatively thinner cortex was found in the perirolandic region and the parieto-occipital lobe. In the right hemisphere, relatively thinner cortex was found in the parietal lobe, posterior superior temporal gyrus, and lateral temporal lobe. These regions of cortical thinning overlapped with the regions of cortex that undergo normal age-related thinning. Conclusion: The spatial distribution of cortical thinning suggested that the areas of cortex that are undergoing development are more sensitive to the effects of treatment of medulloblastoma. Such quantitative methods may improve our understanding of the biologic effects that treatment has on the cerebral development and their neuropsychological implications.

Liu, Arthur K. [Harvard Combined Radiation Oncology Program, Harvard Medical School, Boston, MA (United States)]. E-mail: aliu1@partners.org; Marcus, Karen J. [Department of Radiation Oncology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (United States); Fischl, Bruce [Athinoula A. Martinos Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA (United States); Department of Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Division of Health Sciences and Technology, Cambridge, MA (United States); Grant, P. Ellen [Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Young Poussaint, Tina [Department of Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Rivkin, Michael J. [Departments of Neurology, Psychiatry, and Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Davis, Peter [Departments of Neurology, Psychiatry, and Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Tarbell, Nancy J. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Yock, Torunn I. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

2007-07-15

131

Magnetoencephalographic signatures of right prefrontal cortex involvement in response inhibition.  

PubMed

The prefrontal cortex has a pivotal role in top-down control of cognitive and sensory functions. In complex go-nogo tasks, the right dorsolateral prefrontal cortex is considered to be important for guiding the response inhibition. However, little is known about the temporal dynamics and neurophysiological nature of this activity. To address this issue, we recorded magnetoencephalographic brain activity in 20 women during a visual go-nogo task. The right dorsolateral prefrontal cortex showed an increase for the amplitude of the event-related fields and an increase in induced alpha frequency band activity for nogo in comparison to go trials. The peak of this prefrontal activity preceded the mean reaction time of around 360 ms for go trials, and thus supports the proposed role of right dorsolateral prefrontal cortex in gating the response inhibition and further suggests that right prefrontal alpha band activity might be involved in this gating. However, the results in right dorsolateral prefrontal cortex were similar for both successful and unsuccessful response inhibition. In these conditions, we instead observed pre- and poststimulus differences in alpha band activity in occipital and central areas. Thus, successful response inhibition seemed to additionally depend on prestimulus anticipatory alpha desynchronization in sensory areas as it was reduced prior to unsuccessful response inhibition. In conclusion, we suggest a role for functional inhibition by alpha synchronization not only in sensory, but also in prefrontal areas. PMID:24845057

Hege, Maike A; Preissl, Hubert; Stingl, Krunoslav T

2014-10-01

132

Dissociation of object and spatial visual processing pathways in human extrastriate cortex  

SciTech Connect

The existence and neuroanatomical locations of separate extrastriate visual pathways for object recognition and spatial localization were investigated in healthy young men. Regional cerebral blood flow was measured by positron emission tomography and bolus injections of H2(15)O, while subjects performed face matching, dot-location matching, or sensorimotor control tasks. Both visual matching tasks activated lateral occipital cortex. Face discrimination alone activated a region of occipitotemporal cortex that was anterior and inferior to the occipital area activated by both tasks. The spatial location task alone activated a region of lateral superior parietal cortex. Perisylvian and anterior temporal cortices were not activated by either task. These results demonstrate the existence of three functionally dissociable regions of human visual extrastriate cortex. The ventral and dorsal locations of the regions specialized for object recognition and spatial localization, respectively, suggest some homology between human and nonhuman primate extrastriate cortex, with displacement in human brain, possibly related to the evolution of phylogenetically newer cortical areas.

Haxby, J.V.; Grady, C.L.; Horwitz, B.; Ungerleider, L.G.; Mishkin, M.; Carson, R.E.; Herscovitch, P.; Schapiro, M.B.; Rapoport, S.I. (National Institutes of Health, Bethesda, MD (USA))

1991-03-01

133

Neuropsychologia xxx (2004) xxxxxx Segregation and persistence of form in the lateral occipital complex  

E-print Network

Neuropsychologia xxx (2004) xxx­xxx Segregation and persistence of form in the lateral occipital.neuropsychologia.2004.06.020 #12;2 S. Ferber et al. / Neuropsychologia xxx (2004) xxx­xxx in this area regardless

Vilis, Tutis

134

Traumatic atlanto-occipital dislocation presenting with Dysphagia as the chief complaint: a case report.  

PubMed

We report a patient with traumatic atlanto-occipital dislocation who presented with dysphagia as the chief complaint. A 59-year-old man complained of swallowing difficulty for 2 months after trauma to the neck. On physical examination, there was atrophy of the right sternocleidomastoid and upper trapezius muscles, and the tongue was deviated to the right. In a videofluoroscopic swallowing study, penetration and aspiration were not seen, food residue remained in the right vallecula and pyriform sinus, and there was decreased motion of the soft palate, pharynx and larynx. Electromyography confirmed a right spinal accessory nerve lesion. Magnetic resonance imaging confirmed atlanto-occipital dislocation. Dysphagia in atlanto-occipital dislocation is induced by medullary compression and lower cranial nerve injury. Therefore, in survivors who are diagnosed with atlanto-occipital dislocation, any neurological symptoms should be carefully evaluated. PMID:23869345

Choi, Eun Hye; Jun, Ah Young; Choi, Eun Hi; Shin, Ka Young; Cho, Ah Ra

2013-06-01

135

Traumatic Atlanto-Occipital Dislocation Presenting With Dysphagia as the Chief Complaint: A Case Report  

PubMed Central

We report a patient with traumatic atlanto-occipital dislocation who presented with dysphagia as the chief complaint. A 59-year-old man complained of swallowing difficulty for 2 months after trauma to the neck. On physical examination, there was atrophy of the right sternocleidomastoid and upper trapezius muscles, and the tongue was deviated to the right. In a videofluoroscopic swallowing study, penetration and aspiration were not seen, food residue remained in the right vallecula and pyriform sinus, and there was decreased motion of the soft palate, pharynx and larynx. Electromyography confirmed a right spinal accessory nerve lesion. Magnetic resonance imaging confirmed atlanto-occipital dislocation. Dysphagia in atlanto-occipital dislocation is induced by medullary compression and lower cranial nerve injury. Therefore, in survivors who are diagnosed with atlanto-occipital dislocation, any neurological symptoms should be carefully evaluated. PMID:23869345

Choi, Eun Hye; Choi, Eun Hi; Shin, Ka Young; Cho, Ah Ra

2013-01-01

136

Three Cases with Visual Hallucinations following Combined Ocular and Occipital Damage  

PubMed Central

Charles Bonnet syndrome is an underrecognized disease that involves visual hallucinations in visually impaired patients. We present the cases of three patients who experienced complex visual hallucinations following various pathomechanisms. In two cases, diagnosis showed coexistence of occipital lobe damage with ocular damage, while in the third case it showed occipital lobe damage with retrobulbar optic neuritis. Theories of pathogenesis and the neuroanatomical basis of complex visual hallucinations are discussed and supported by literature review. PMID:24376461

Paradowski, Bogus?aw; Kowalczyk, Edyta; Chojdak-?ukasiewicz, Justyna; S?u?ewska-Nied?wied?, Monika

2013-01-01

137

Experience-Related Structural Changes of Degenerated Occipital White Matter in Late-Blind Humans – A Diffusion Tensor Imaging Study  

PubMed Central

Late-blind humans can learn to understand speech at ultra-fast syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. Thus, the observed functional cross-modal recruitment of occipital cortex might facilitate ultra-fast speech processing in these individuals. To further elucidate the structural prerequisites of this skill, diffusion tensor imaging (DTI) was conducted in late-blind subjects differing in their capability of understanding ultra-fast speech. Fractional anisotropy (FA) was determined as a quantitative measure of the directionality of water diffusion, indicating fiber tract characteristics that might be influenced by blindness as well as the acquired perceptual skills. Analysis of the diffusion images revealed reduced FA in late-blind individuals relative to sighted controls at the level of the optic radiations at either side and the right-hemisphere dorsal thalamus (pulvinar). Moreover, late-blind subjects showed significant positive correlations between FA and the capacity of ultra-fast speech comprehension within right-hemisphere optic radiation and thalamus. Thus, experience-related structural alterations occurred in late-blind individuals within visual pathways that, presumably, are linked to higher order frontal language areas. PMID:25830371

Dietrich, Susanne; Hertrich, Ingo; Kumar, Vinod; Ackermann, Hermann

2015-01-01

138

Neural Responses in Parietal and Occipital Areas in Response to Visual Events Are Modulated by Prior Multisensory Stimuli  

PubMed Central

The effect of multi-modal vs uni-modal prior stimuli on the subsequent processing of a simple flash stimulus was studied in the context of the audio-visual ‘flash-beep’ illusion, in which the number of flashes a person sees is influenced by accompanying beep stimuli. EEG recordings were made while combinations of simple visual and audio-visual stimuli were presented. The experiments found that the electric field strength related to a flash stimulus was stronger when it was preceded by a multi-modal flash/beep stimulus, compared to when it was preceded by another uni-modal flash stimulus. This difference was found to be significant in two distinct timeframes – an early timeframe, from 130–160 ms, and a late timeframe, from 300–320 ms. Source localisation analysis found that the increased activity in the early interval was localised to an area centred on the inferior and superior parietal lobes, whereas the later increase was associated with stronger activity in an area centred on primary and secondary visual cortex, in the occipital lobe. The results suggest that processing of a visual stimulus can be affected by the presence of an immediately prior multisensory event. Relatively long-lasting interactions generated by the initial auditory and visual stimuli altered the processing of a subsequent visual stimulus. PMID:24391939

Innes-Brown, Hamish; Barutchu, Ayla; Crewther, David P.

2013-01-01

139

Preferential effect of isoflurane on top-down vs. bottom-up pathways in sensory cortex  

PubMed Central

The mechanism of loss of consciousness (LOC) under anesthesia is unknown. Because consciousness depends on activity in the cortico-thalamic network, anesthetic actions on this network are likely critical for LOC. Competing theories stress the importance of anesthetic actions on bottom-up “core” thalamo-cortical (TC) vs. top-down cortico-cortical (CC) and matrix TC connections. We tested these models using laminar recordings in rat auditory cortex in vivo and murine brain slices. We selectively activated bottom-up vs. top-down afferent pathways using sensory stimuli in vivo and electrical stimulation in brain slices, and compared effects of isoflurane on responses evoked via the two pathways. Auditory stimuli in vivo and core TC afferent stimulation in brain slices evoked short latency current sinks in middle layers, consistent with activation of core TC afferents. By contrast, visual stimuli in vivo and stimulation of CC and matrix TC afferents in brain slices evoked responses mainly in superficial and deep layers, consistent with projection patterns of top-down afferents that carry visual information to auditory cortex. Responses to auditory stimuli in vivo and core TC afferents in brain slices were significantly less affected by isoflurane compared to responses triggered by visual stimuli in vivo and CC/matrix TC afferents in slices. At a just-hypnotic dose in vivo, auditory responses were enhanced by isoflurane, whereas visual responses were dramatically reduced. At a comparable concentration in slices, isoflurane suppressed both core TC and CC/matrix TC responses, but the effect on the latter responses was far greater than on core TC responses, indicating that at least part of the differential effects observed in vivo were due to local actions of isoflurane in auditory cortex. These data support a model in which disruption of top-down connectivity contributes to anesthesia-induced LOC, and have implications for understanding the neural basis of consciousness. PMID:25339873

Raz, Aeyal; Grady, Sean M.; Krause, Bryan M.; Uhlrich, Daniel J.; Manning, Karen A.; Banks, Matthew I.

2014-01-01

140

Occipital lobe epilepsy: electroclinical manifestations, electrocorticography, cortical stimulation and outcome in 42 patients treated between 1930 and 1991. Surgery of occipital lobe epilepsy.  

PubMed

Our study documents the clinical and electrographic findings in 42 patients with medically refractory occipital lobe epilepsy, who underwent surgery at the Montreal Neurological Institute between 1930 and 1991, and the evolving manner in which those patients were studied by successive generations of investigators. In more than two-thirds of the patients the clinical manifestations indicated the occipital onset of the seizures. Seventy-three percent experienced visual aurae, of which elementary hallucinations were the most common and 12 also had ictal blindness. Other occipital manifestations included: contralateral eye deviation, blinking, a sensation of eye movement and nystagmoid eye movements. Intra-operative cortical stimulation elicited a habitual aura in 37% of 29 patients. Lateralizing clinical features were seen in almost two-thirds of patients: contralateral head deviation occurred in half, 59% had visual field defects contralateral to the epileptogenic area and 64% had abnormal imaging studies ipsilateral to the side of surgery. More than one-third of patients exhibited more than one seizure type, suggesting ictal spread to temporal or frontal lobe: 50% had typical temporal lobe automatisms, and 38% exhibited focal motor seizure activity. Surface electroencephalogram (EEG) recordings showed posterior temporal-occipital epileptiform discharges in 46% of patients. Only 18% had electronegative spiking limited to 01 or 02. Large epileptogenic areas were often found on intracranial recording with depth electrodes and on electrocorticography. Pre-excision electrocorticography spiking was restricted to the occipital lobe in only 13 out of 34 patients. More often spiking also involved the posterior temporal and posterior parietal regions. Twenty-three patients underwent only occipital resections; five had only temporal resections, so as to preserve the visual fields, and the remaining 14 patients had extensive resections, which included the posterior temporal or posterior parietal regions. A follow-up period of 1 to 46 yrs (mean 17 yrs) was available for 37 patients. Forty-six percent became seizure free and 21% had a significant reduction in seizure frequency. A better outcome was observed in those patients in whom there was no post-resection electrocorticographic or surface EEG epileptiform discharge, or who exhibited an occipital lobe lesion. PMID:1486456

Salanova, V; Andermann, F; Olivier, A; Rasmussen, T; Quesney, L F

1992-12-01

141

Pediatric atlanto-occipital dissociation: radiographic findings and clinical outcome  

PubMed Central

Study design:?Retrospective diagnostic feasibility study and clinical review. Objectives:?To evaluate the feasibility of making an initial atlanto-occipital dissociation (AOD) diagnosis from four radiological measurements of the craniocervical relationship on lateral cervical spine x-rays and to assess the AOD patients' clinical outcomes relative to their magnetic resonance imaging (MRI) findings. Methods:?The Powers ratio, Wackenheim line, basion-dens distance (BDD), and the C1/2:C2/3 interspinous ratio were measured in 58 pediatric controls and ten MRI-confirmed patients with AOD. The ability to identify the required anatomical landmarks and make the measurements was noted and sensitivity and specificity calculated. The correspondence between the clinical presentation and outcomes for patients with AOD and their MRI features was investigated. Results:?Clear landmarks for measuring interspinous ratio and Wackenheim line were confirmed by all x-rays. The BDD was measureable in 90% and the Powers ratio could be calculated in only possible in 59%. The interspinous ratio and BDD offered high sensitivities and specificity. Although the Wackenheim line was consistantly measured, it conferred a low sensitivity but reasonable specificity. The Powers ratio offered high specificity with low sensitivity. On MRI, all patients with AOD had apical ligament disruption, with a high rate of interspinous ligamentous injury (8/9); prevertebral swelling (7/9); retroclival hematoma (6/9); and tectorial membrane injury (4/9). The only MRI feature associated with poor outcome was that of altered cord signal. Both patients who died had cord signal changes on T1- and T2-weighted images. The third patient with cord signal change was limited to T2 changes with a normal T1. He had a C5-L3 sensory deficit that resolved. The degree of tectorial membrane injury did not appear to influence outcome. Conclusions:?The BDD and interspinous ratio offer the best measures for initial x-ray diagnosis of AOD. This will alert the surgeon to the need for MRI. These patients often have a reduced level of consciousness, thus making clinical evaluation difficult. The MRI findings, although apparently indicative of severe abnormality, did not actually correspond to outcomes except for the presence of T1 cord signal changes that matched with severe neurological impairment and subsequent death. PMID:23236302

du Plessis, Jean-Pierre; Dix-Peek, Stewart; Hoffman, Eduard Bernard; Wieselthaler, Nicky; Dunn, Robert Neil

2012-01-01

142

PAPER www.rsc.org/loc | Lab on a Chip Detecting bacteria and determining their susceptibility to antibiotics by  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip Detecting bacteria and determining their susceptibility of bacteria in samples, including complex biological matrices, without pre- incubation. Unlike conventional of bacteria to detectable levels, this method confines indi- vidual bacteria into droplets nanoliters

Ismagilov, Rustem F.

143

TECHNICAL NOTE www.rsc.org/loc | Lab on a Chip Neutravidin micropatterning by deep UV irradiation  

E-print Network

TECHNICAL NOTE www.rsc.org/loc | Lab on a Chip Neutravidin micropatterning by deep UV irradiation February 2008, Accepted 16th June 2008 First published as an Advance Article on the web 13th August 2008 by exposure to deep UV irradiation. Neutravidin is physically absorbed onto the glass or quartz substrate

Hancock, William O.

144

PAPER www.rsc.org/loc | Lab on a Chip Microfluidic device for label-free measurement of platelet activation  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip Microfluidic device for label-free measurement of platelet a new microfluidic method for the rapid assessment of platelet size and morphology in whole blood, platelet specific, antibody PE-anti-CD41, was run through the device and the positions of fluorescent

145

www.rsc.org/loc Volume8|Number4|April2008|Pages501632 ISSN1473-0197  

E-print Network

for isolating specific proteins from sub-microlitre volumes of E. Coli cell lysate. Recombinant proteins proteins often involve chromatography or centrifugation, which are labor-intensive and scale poorly www.rsc.org/loc | Lab on a Chip Rapid, continuous purification of proteins in a microfluidic device

Singh, Anup

146

PAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves and pumps  

E-print Network

that utilize a featureless polydimethylsiloxane (PDMS) membrane bonded between two etched glass wafers, complicating the determination of their on-chip concentration.7 Some reusable glass microfluidic devices mustPAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves

Manalis, Scott

147

Graphical Analysis of Electromagnetic Coupling on B-737 and B-757 Aircraft for VOR and LOC IPL Data  

NASA Technical Reports Server (NTRS)

Electromagnetic coupling measurements were performed from numerous passenger cabin locations to aircraft instrument landing system localizer (LOC) and VHF Omni-Ranging (VOR) systems. This paper presents and compares the data for B-757 and B-737 airplanes, and provides a basis for fuzzy modeling of coupling patterns in different types of airplanes and airplanes with different antenna locations.

Jafri, Madiha; Ely, Jay; Vahala, Linda

2005-01-01

148

PAPER www.rsc.org/loc | Lab on a Chip Microfluidic device for immunoassays based on surface plasmon resonance  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip Microfluidic device for immunoassays based on surface plasmon to about 60 min. Introduction Immunoassays, such as the enzyme-linked immunosorbent assay (ELISA), have-step immunoassays. This feature limits their applications, especially when the detection method is sensitive

Zare, Richard N.

149

Occipital meningoencephalocele with Cleft Lip, Cleft Palate and Limb Abnormalities- A Case Report.  

PubMed

A 21-week-old still born female fetus with occipital encepholocele, cleft lip and cleft palate was received from the Department of Obstetrics and Gynecology, Mahatma Gandhi Medical College and Research Institute, Pondicherry and was studied in detail. It was born to Primigravida, of a second degree consanguineous marriage, with unremarkable family history. The biometric measurements were noted which corresponded to the age of the fetus. Further the fetus was embalmed and dissected. On examination an encephalocele of 2.7×1.5 cm was seen in the occipital region with a midline defect in the occipital bone and herniated brain tissue. Other anomalies observed were right unilateral cleft lip, right cleft palate, and bilateral syndactyly of the lower limbs and associated Congenital Talipus Equino Varus of the right foot. Other internal organs were developed appropriate for the age of the fetus. PMID:25653933

Ganapathy, Arthi; T, Sadeesh; Swer, Mary Hydrina; Rao, Sudha

2014-12-01

150

Occipital meningoencephalocele with Cleft Lip, Cleft Palate and Limb Abnormalities- A Case Report  

PubMed Central

A 21-week-old still born female fetus with occipital encepholocele, cleft lip and cleft palate was received from the Department of Obstetrics and Gynecology, Mahatma Gandhi Medical College and Research Institute, Pondicherry and was studied in detail. It was born to Primigravida, of a second degree consanguineous marriage, with unremarkable family history. The biometric measurements were noted which corresponded to the age of the fetus. Further the fetus was embalmed and dissected. On examination an encephalocele of 2.7×1.5 cm was seen in the occipital region with a midline defect in the occipital bone and herniated brain tissue. Other anomalies observed were right unilateral cleft lip, right cleft palate, and bilateral syndactyly of the lower limbs and associated Congenital Talipus Equino Varus of the right foot. Other internal organs were developed appropriate for the age of the fetus. PMID:25653933

T, Sadeesh; Swer, Mary Hydrina; Rao, Sudha

2014-01-01

151

Evidence for both reaching and grasping activity in the medial parieto-occipital cortex of the macaque  

Microsoft Academic Search

In humans, the caudal pole of the superior parietal lobule is involved in the control of both reaching and grasping movements, whereas in monkey it is reported to be involved only in the control of reaching. Using single-unit recordings from trained macaque monkeys, we investigated whether area V6A, a visuomotor area located in the caudal part of the posterior parietal

Patrizia Fattori; Rossella Breveglieri; Katia Amoroso; Claudio Galletti

2004-01-01

152

Anticipatory Biasing of Visuospatial Attention Indexed by Retinotopically Specific a-Band Electroencephalography Increases over Occipital Cortex  

Microsoft Academic Search

a-Band (8-14 Hz) oscillatory EEG activity was examined with high-density scalp electrical recording during the cue-stimulus interval of an endogenous spatial cueing paradigm. In different blocks, cued spatial locations (left or right) were in either the upper or lower visual field, and attended stimuli were either oriented Ts or moving dots. Distractor stimuli were equally likely in the uncued hemifield.

Michael S. Worden; John J. Foxe; Norman Wang; Gregory V. Simpson

2000-01-01

153

MetaLocGramN: A meta-predictor of protein subcellular localization for Gram-negative bacteria.  

PubMed

Subcellular localization is a key functional characteristic of proteins. It is determined by signals encoded in the protein sequence. The experimental determination of subcellular localization is laborious. Thus, a number of computational methods have been developed to predict the protein location from sequence. However predictions made by different methods often disagree with each other and it is not always clear which algorithm performs best for the given cellular compartment. We benchmarked primary subcellular localization predictors for proteins from Gram-negative bacteria, PSORTb3, PSLpred, CELLO, and SOSUI-GramN, on a common dataset that included 1056 proteins. We found that PSORTb3 performs best on the average, but is outperformed by other methods in predictions of extracellular proteins. This motivated us to develop a meta-predictor, which combines the primary methods by using the logistic regression models, to take advantage of their combined strengths, and to eliminate their individual weaknesses. MetaLocGramN runs the primary methods, and based on their output classifies protein sequences into one of five major localizations of the Gram-negative bacterial cell: cytoplasm, plasma membrane, periplasm, outer membrane, and extracellular space. MetaLocGramN achieves the average Matthews correlation coefficient of 0.806, i.e. 12% better than the best individual primary method. MetaLocGramN is a meta-predictor specialized in predicting subcellular localization for proteins from Gram-negative bacteria. According to our benchmark, it performs better than all other tools run independently. MetaLocGramN is a web and SOAP server available for free use by all academic users at the URL http://iimcb.genesilico.pl/MetaLocGramN. This article is part of a Special Issue entitled: Computational Methods for Protein Interaction and Structural Prediction. PMID:22705560

Magnus, Marcin; Pawlowski, Marcin; Bujnicki, Janusz M

2012-12-01

154

Economic evaluation of "pulse dose" radiofrequency in the treatment of occipital neuralgia headache.  

PubMed

Headache occipital neuralgia is an example of pain-disease for which treatment both pharmacological protocols and invasive methods are used. Among the latter, the RF (Radiofrequency) pulse-dose has been of interest for the prospects of analgesic efficacy, safety and patient compliance, although at the moment only data concerning the pulsed RF and not the RF pulse-dose, that represents its evolution, are discussed in scientific literature. The purpose of this study is a "simple" economic evaluation of this method in headache occipital neuralgia. PMID:23905049

Giovannini, Vittoria; Pusateri, Rachele; Russo, Viera; Viscardi, Daniela; Palomba, Rosa

2012-05-01

155

Economic Evaluation of “Pulse Dose” Radiofrequency in the Treatment of Occipital Neuralgia Headache  

PubMed Central

Headache occipital neuralgia is an example of pain-disease for which treatment both pharmacological protocols and invasive methods are used. Among the latter, the RF (Radiofrequency) pulse-dose has been of interest for the prospects of analgesic efficacy, safety and patient compliance, although at the moment only data concerning the pulsed RF and not the RF pulse-dose, that represents its evolution, are discussed in scientific literature. The purpose of this study is a “simple” economic evaluation of this method in headache occipital neuralgia. PMID:23905049

Giovannini, Vittoria; Pusateri, Rachele; Russo, Viera; Viscardi, Daniela; Palomba, Rosa

2012-01-01

156

Benign occipital unicameral bone cyst causing lower cranial nerve palsies complicated by iophendylate arachnoiditis  

PubMed Central

A 20 year old girl presented with a history of neck and occipital pain for six weeks, which was found to be due to a unicameral bone cyst of the left occipital condylar region. The differential diagnosis of bone cysts in the skull is discussed. Six months after the operation, the patient again presented with backache due to adhesive arachnoiditis. The latter was believed to have arisen as a result of a combination of spinal infective meningitis and intrathecal ethyl iodophenyl undecylate (iophendylate, Myodil, Pantopaque). The nature of meningeal reactions to iophendylate and the part played by intrathecal corticosteroids in relieving the arachnoiditis in the present case are discussed. Images

Bradley, W. G.; Kalbag, R. M.; Ramani, P. S.; Tomlinson, B. E.

1974-01-01

157

Fatal airbag-mediated atlanto-occipital dislocation in a child.  

PubMed

An atlanto-occipital dislocation is a rare airbag-induced injury in trauma patients. We report a case of an atlanto-occipital dislocation in a 6-year-old patient who was an unrestrained passenger in the front seat of a vehicle involved in a low-speed motor vehicle accident. This case illustrates the fatal threat of airbag deployment to the child passenger travelling in the vehicle front seat even in a low-speed collision, and supports the recommendation that children under 12 years of age travelling in vehicles with dual airbag systems should be seated in the back. PMID:22135564

Hassan, Radhiana; Mohd Yusof, Mubarak; Kamarudin, Norie Azilah

2010-10-01

158

Fatal Airbag-Mediated Atlanto-Occipital Dislocation in a Child  

PubMed Central

An atlanto-occipital dislocation is a rare airbag-induced injury in trauma patients. We report a case of an atlanto-occipital dislocation in a 6-year-old patient who was an unrestrained passenger in the front seat of a vehicle involved in a low-speed motor vehicle accident. This case illustrates the fatal threat of airbag deployment to the child passenger travelling in the vehicle front seat even in a low-speed collision, and supports the recommendation that children under 12 years of age travelling in vehicles with dual airbag systems should be seated in the back. PMID:22135564

Hassan, Radhiana; Mohd Yusof, Mubarak; Kamarudin, Norie Azilah

2010-01-01

159

Suture material for flexor tendon repair: 3–0 V-Loc versus 3–0 Stratafix in a biomechanical comparison ex vivo  

PubMed Central

Background Barbed suture material offers the possibility of knotless flexor tendon repair, as suggested in an increasing number of biomechanical studies. There are currently two different absorbable barbed suture products available, V-Loc™ and Stratafix™, and both have not been compared to each other with regard to flexor tendon repair. The purpose of this study was to evaluate both suture materials for primary stability under static and cyclic loading in a biomechanical ex vivo model. Methods Forty fresh porcine flexor digitorum profundus tendons were randomized in two groups. A four-strand modified Kessler suture technique was used to repair the tendon either with a 3–0 V-Loc™ or 3–0 Stratafix™ without a knot. Parameters of interest were mode of failure, 2-mm gap formation force, displacement, stiffness and maximum load under static and cyclic testing. Results The maximum load was 42.3?±?7.2 for the Stratafix™ group and 50.7?±?8.8 N for the V-Loc™ group. Thus, the ultimate tensile strength was significantly higher for V-Loc™ (p?Loc™ group (n.s.). Displacement was 2.65?±?0.56 mm in the V-Loc™ group and 2.71?±?0.59 mm in the Stratafix™ group (n.s.). Stiffness was 4.24?±?0.68 (N/mm) in the V-Loc™ group and 3.85?±?0.55 (N/mm) the Stratafix™ group (n.s.). Those measured differences were not significant. Conclusion V-Loc™ demonstrates a higher maximum load in tendon reconstruction. The differences in 2-mm gap formation force, displacement and stiffness were not significant. Hereby, the V-Loc™ has an advantage when used as unidirectional barbed suture for knotless flexor tendon repair. PMID:25205062

2014-01-01

160

The regional gradient of critical flicker frequency after frontal or occipital lobe injury  

Microsoft Academic Search

The regional gradient of CFF was measured in normal subjects and in patients with either occipital or frontal lobe injury. For target sizes used the regional gradient for all groups was a decreasing and approximately logarithmic function of the angular distance from the fovea. Under all conditions the area effect was greatest in the fovea for all groups. No depression

William S. Battersby

1951-01-01

161

Occipital Nerve Stimulation in Fibromyalgia: A Double-Blind Placebo-Controlled Pilot Study  

E-print Network

Occipital Nerve Stimulation in Fibromyalgia: A Double-Blind Placebo-Controlled Pilot Study) as a surgical treatment for fibromyalgia in a placebo-controlled design. Materials and Methods: Eleven patients), the number of trigger points, and overall morbidity (fibromyalgia impact question- naire). There were

O'Toole, Alice J.

162

Atlanto-occipital dislocation with retroclival hematoma in a pediatric patient presenting to the emergency department.  

PubMed

Atlanto-occipital dislocation is a rare, oftentimes fatal injury sustained from high-impact trauma. It is seen more often in children compared with adults. In the past decade, there are more pediatric survivors presenting to the emergency department for treatment. This case reviews the presentation, diagnosis, and treatment of a child who survived this injury. PMID:21057281

Diaz, Rebecca; Zouros, Alexander; Stewart, Gail M

2010-11-01

163

Atlanto-axial subluxation after pyogenic spondylitis of the atlanto-occipital joint.  

PubMed

This report presents a case of atlanto-axial subluxation after treatment of pyogenic spondylitis of the atlanto-occipital joint. A 60-year-old male had 1-month history of neck pain with fever. Magnetic resonance imaging showed inflammation around the odontoid process. Intravenous antibiotic therapy was administrated immediately. After 6 weeks, CRP had returned almost to normal. After 4 months, laboratory data was still normal, but the patient experienced increasing neck pain. Lateral cervical radiography in the neutral position showed instability between C1 and C2. Computed tomography showed a bony union of the atlanto-occipital joint and severe destruction of the atlanto-axial joint on the left side. Transarticular screw fixation for the atlanto-axial joint was performed. A lateral cervical radiograph in the neutral position after surgery showed a solid bony union. Neck pain improved following surgery. We speculate that spondylitis of the atlanto-occipital joint induced a loosening of the transverse ligament and articulation of the atlanto-axial joint. A bony fusion of the atlanto-occipital joint after antibiotic treatment resolved the pyogenic inflammation concentrated stress to the damaged atlanto-axial joint, resulting in further damage. The atlanto-axial instability was finally managed by the insertion of a transarticular screw. PMID:21140176

Tsunoda, Kazuhiko; Iizuka, Haku; Sorimachi, Yasunori; Ara, Tsuyoshi; Nishinome, Masahiro; Takechi, Yasuhiko; Takagishi, Kenji

2011-07-01

164

The white matter of the human cerebrum: Part I The occipital lobe by Heinrich Sachs  

PubMed Central

This is the first complete translation of Heinrich Sachs' outstanding white matter atlas dedicated to the occipital lobe. This work is accompanied by a prologue by Prof Carl Wernicke who for many years was Sachs' mentor in Breslau and enthusiastically supported his work. PMID:25527430

Forkel, Stephanie J.; Mahmood, Sajedha; Vergani, Francesco; Catani, Marco

2015-01-01

165

Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM  

E-print Network

Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM meditation practice has gained increasing attention as a non-pharmacological intervention to provide health conditions. However, the effects of meditation training on brain activity still need to be fully

Wisconsin at Madison, University of

166

Prenatal Diagnosis of Occipital Dermal Sinus Associated with Hemangioma Using Ultrasound and MRI  

Microsoft Academic Search

Objective: We report a case of prenatal diagnosis and postpartum management of a subcutaneous tumor without intracranial communication. Methods: An occipital tumor without intracranial communication was found on ultrasound scan in the 21st week of pregnancy. Using MRI, the diagnosis was confirmed. Subcutaneous localization of the tumor was verified and communication with intracranial space excluded. Results: The newborn was delivered

Hana Viskova; Pavel Calda; Zdenek Zizka; Manuela Vaneckova; David Hoza; Anna Zuntova

2006-01-01

167

Retinotopic maps and foveal suppression in the visual cortex of amblyopic adults  

PubMed Central

Amblyopia is a developmental visual disorder associated with loss of monocular acuity and sensitivity as well as profound alterations in binocular integration. Abnormal connections in visual cortex are known to underlie this loss, but the extent to which these abnormalities are regionally or retinotopically specific has not been fully determined. This functional magnetic resonance imaging (fMRI) study compared the retinotopic maps in visual cortex produced by each individual eye in 19 adults (7 esotropic strabismics, 6 anisometropes and 6 controls). In our standard viewing condition, the non-tested eye viewed a dichoptic homogeneous mid-level grey stimulus, thereby permitting some degree of binocular interaction. Regions-of-interest analysis was performed for extrafoveal V1, extrafoveal V2 and the foveal representation at the occipital pole. In general, the blood oxygenation level-dependent (BOLD) signal was reduced for the amblyopic eye. At the occipital pole, population receptive fields were shifted to represent more parafoveal locations for the amblyopic eye, compared with the fellow eye, in some subjects. Interestingly, occluding the fellow eye caused an expanded foveal representation for the amblyopic eye in one early–onset strabismic subject with binocular suppression, indicating real-time cortical remapping. In addition, a few subjects actually showed increased activity in parietal and temporal cortex when viewing with the amblyopic eye. We conclude that, even in a heterogeneous population, abnormal early visual experience commonly leads to regionally specific cortical adaptations. PMID:17627994

Conner, Ian P; Odom, J Vernon; Schwartz, Terry L; Mendola, Janine D

2007-01-01

168

Synaptic proteins and choline acetyltransferase loss in visual cortex in dementia with Lewy bodies.  

PubMed

Functional neuroimaging studies have consistently reported abnormalities in the visual cortex in patients with dementia with Lewy bodies (DLB), but their neuropathologic substrates are poorly understood. We analyzed synaptic proteins and choline acetyltransferase (ChAT) in the primary (BA17) and association (BAs18/19) visual cortex in DLB and similar aged control and Alzheimer disease (AD) subjects. We found lower levels of synaptophysin, syntaxin, SNAP-25, and ?-synuclein in DLB subjects versus both aged control (68%-78% and 27%-72% for BA17 and BAs18/19, respectively) and AD cases (54%-67% and 10%-56% for BA17 and BAs18/19, respectively). The loss in ChAT activity in DLB cases was also greater in BA17 (72% and 87% vs AD and control values, respectively) than in BAs18/19 (52% and 65% vs AD and control groups, respectively). The observed synaptic and ChAT changes in the visual cortices were not associated with tau or ?-amyloid pathology in the occipital or the frontal, temporal, and parietal neocortex. However, the neocortical densities of LBs, particular those in BA17 and BAs18/19, correlated with lower synaptic and ChAT levels in these brain areas. These findings draw attention to molecular changes within the primary visual cortex in DLB and correlate with the neuroimaging findings within the occipital lobe in patients with this disorder. PMID:23242284

Mukaetova-Ladinska, Elizabeta B; Andras, Alina; Milne, Joan; Abdel-All, Zeinab; Borr, Iwo; Jaros, Evelyn; Perry, Robert H; Honer, William G; Cleghorn, Andrea; Doherty, Jeanette; McIntosh, Gary; Perry, Elaine K; Kalaria, Raj N; McKeith, Ian G

2013-01-01

169

MCT8 expression in human fetal cerebral cortex is reduced in severe intrauterine growth restriction.  

PubMed

The importance of the thyroid hormone (TH) transporter, monocarboxylate transporter 8 (MCT8), to human neurodevelopment is highlighted by findings of severe global neurological impairment in subjects with MCT8 (SLC16A2) mutations. Intrauterine growth restriction (IUGR), usually due to uteroplacental failure, is associated with milder neurodevelopmental deficits, which have been partly attributed to dysregulated TH action in utero secondary to reduced circulating fetal TH concentrations and decreased cerebral thyroid hormone receptor expression. We postulate that altered MCT8 expression is implicated in this pathophysiology; therefore, in this study, we sought to quantify changes in cortical MCT8 expression with IUGR. First, MCT8 immunohistochemistry was performed on occipital and parietal cerebral cortex sections obtained from appropriately grown for gestational age (AGA) human fetuses between 19 weeks of gestation and term. Secondly, MCT8 immunostaining in the occipital cortex of stillborn IUGR human fetuses at 24-28 weeks of gestation was objectively compared with that in the occipital cortex of gestationally matched AGA fetuses. Fetuses demonstrated widespread MCT8 expression in neurons within the cortical plate and subplate, in the ventricular and subventricular zones, in the epithelium of the choroid plexus and ependyma, and in microvessel wall. When complicated by IUGR, fetuses showed a significant fivefold reduction in the percentage area of cortical plate immunostained for MCT8 compared with AGA fetuses (P<0.05), but there was no significant difference in the proportion of subplate microvessels immunostained. Cortical MCT8 expression was negatively correlated with the severity of IUGR indicated by the brain:liver weight ratios (r(2)=0.28; P<0.05) at post-mortem. Our results support the hypothesis that a reduction in MCT8 expression in the IUGR fetal brain could further compromise TH-dependent brain development. PMID:24204008

Chan, Shiao Y; Hancox, Laura A; Martín-Santos, Azucena; Loubière, Laurence S; Walter, Merlin N M; González, Ana-Maria; Cox, Phillip M; Logan, Ann; McCabe, Christopher J; Franklyn, Jayne A; Kilby, Mark D

2014-02-01

170

MCT8 expression in human fetal cerebral cortex is reduced in severe intrauterine growth restriction  

PubMed Central

The importance of the thyroid hormone (TH) transporter, monocarboxylate transporter 8 (MCT8), to human neurodevelopment is highlighted by findings of severe global neurological impairment in subjects with MCT8 (SLC16A2) mutations. Intrauterine growth restriction (IUGR), usually due to uteroplacental failure, is associated with milder neurodevelopmental deficits, which have been partly attributed to dysregulated TH action in utero secondary to reduced circulating fetal TH concentrations and decreased cerebral thyroid hormone receptor expression. We postulate that altered MCT8 expression is implicated in this pathophysiology; therefore, in this study, we sought to quantify changes in cortical MCT8 expression with IUGR. First, MCT8 immunohistochemistry was performed on occipital and parietal cerebral cortex sections obtained from appropriately grown for gestational age (AGA) human fetuses between 19 weeks of gestation and term. Secondly, MCT8 immunostaining in the occipital cortex of stillborn IUGR human fetuses at 24–28 weeks of gestation was objectively compared with that in the occipital cortex of gestationally matched AGA fetuses. Fetuses demonstrated widespread MCT8 expression in neurons within the cortical plate and subplate, in the ventricular and subventricular zones, in the epithelium of the choroid plexus and ependyma, and in microvessel wall. When complicated by IUGR, fetuses showed a significant fivefold reduction in the percentage area of cortical plate immunostained for MCT8 compared with AGA fetuses (P<0.05), but there was no significant difference in the proportion of subplate microvessels immunostained. Cortical MCT8 expression was negatively correlated with the severity of IUGR indicated by the brain:liver weight ratios (r2=0.28; P<0.05) at post-mortem. Our results support the hypothesis that a reduction in MCT8 expression in the IUGR fetal brain could further compromise TH-dependent brain development. PMID:24204008

Chan, Shiao Y; Hancox, Laura A; Martín-Santos, Azucena; Loubière, Laurence S; Walter, Merlin N M; González, Ana-Maria; Cox, Phillip M; Logan, Ann; McCabe, Christopher J; Franklyn, Jayne A; Kilby, Mark D

2014-01-01

171

Evaluation of spheno-occipital synchondrosis: A review of literature and considerations from forensic anthropologic point of view  

PubMed Central

Cranial sutures and synchondrosis have long been studied by forensic scientists, human anatomists, and anthropologists for estimation of age in different population groups. Observation of the closure of spheno-occipital synchondrosis has an important role to play in the estimation of age in the examination of unknown human remains when a skull is brought for examination. The present article reviews the studies conducted on the closure of spheno-occipital synchondrosis and presents a few valuable considerations that would be essential for carrying out research related to closure of spheno-occipital synchondrosis in humans. PMID:24255553

Krishan, Kewal; Kanchan, Tanuj

2013-01-01

172

Go-no-go task performance improvement after anodal transcranial DC stimulation of the left dorsolateral prefrontal cortex in major depression  

Microsoft Academic Search

BackgroundWe recently showed that repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) can affect the performance in an affective go-no-go (AGN) task. We aimed to extend this previous investigation testing whether one session of anodal transcranial direct current stimulation (tDCS) of the left DLPFC, as compared with anodal occipital and sham tDCS, affects this AGN task performance.

Paulo S. Boggio; Felix Bermpohl; Adriana O. Vergara; Ana L. C. R. Muniz; Fernanda H. Nahas; Priscila B. Leme; Sergio P. Rigonatti; Felipe Fregni

2007-01-01

173

Timely recognition of traumatic atlanto-occipital dislocation in a child based on occipital condyle-C1 interval analysis: excellent neurological recovery.  

PubMed

A case of atlanto-occipital dislocation (AOD) is presented to illustrate the importance of subtle imaging findings and the occipital condyle-C1 interval (CCI) measurement in the evaluation of high cervical spine injury. Although AOD is commonly considered to be fatal, recently there have been an increasing number of reports of children surviving this injury. Prompt recognition and treatment of AOD are crucial for survival. The authors present a case of an 8-year-old boy who sustained a destabilizing injury without bone disruption but with ligamentous tears that rendered his cervical spine unstable from the occiput to the C-1 level. On admission, imaging findings were consistent with tectorial membrane damage, perimedullary subarachnoid hemorrhage, and extraaxial blood from the clivus to the C-2 level. Most standard cervical spine radiological indices were within normal limits except the CCI. After initial management in a cervical collar, the patient was placed in halo vest, and subsequently underwent occiput to C-3 fusion. Timely recognition of the injury and subsequent craniocervical stabilization with internal fixation resulted in full neurological recovery. This report supports CCI as a valuable index for the prompt recognition of AOD. It also supports recent literature suggesting that AOD is a survivable injury with the possibility for an excellent neurological recovery. PMID:20433259

Gluncic, Vicko; Turner, Michael; Kranzler, Leonard; Frim, David

2010-05-01

174

Concurrent occipital bone malformation and atlantoaxial subluxation in a neonatal harbor seal (Phoca vitulina).  

PubMed

A stranded male harbor seal (Phoca vitulina) neonate with progressive clinical signs of ataxia, tremors, and deteriorating consciousness was evaluated using magnetic resonance imaging for suspected cerebellar brain disease prior to euthanasia because of grave prognosis. Magnetic resonance imaging identified occipital bone dysplasia with cerebellar herniation and concurrent atlantoaxial subluxation with spinal cord compression. These imaging findings elucidated the cause of histopathology changes including gliosis of the cerebellum and axonal degeneration and dilation of myelin sheaths of the dorsal funiculus of the spinal cord. Occipital bone dysplasia and/ or atlantoaxial subluxation should be considered as differentials for abnormal neurologic signs in harbor seal neonates. Magnetic resonance imaging is a valuable modality for antemortem diagnosis. PMID:19569493

Dennison, Sophie E; Forrest, Lisa J; Fleetwood, Michelle L; Gulland, Frances M D

2009-06-01

175

Neurofibromatosis Type 1: Transcatheter Arterial Embolization for Ruptured Occipital Arterial Aneurysms  

SciTech Connect

Two cases of ruptured aneurysms in the posterior cervical regions associated with type-1 neurofibromatosis treated by transcatheter embolization are reported. Patients presented with acute onset of swelling and pain in the affected areas. Emergently performed contrast-enhanced CT demonstrated aneurysms and large hematomas widespread in the posterior cervical regions. Angiography revealed aneurysms and extravasations of the occipital artery. Patients were successfully treated by percutaneous transcatheter arterial microcoil embolization. Transcatheter arterial embolization therapy was found to be an effective method for treating aneurysmal rupture in the posterior cervical regions occurring in association with type-1 neurofibromatosis. A literature review revealed that rupture of an occipital arterial aneurysm, in the setting of neurofibromatosis type 1, has not been reported previously.

Kanematsu, Masayuki; Kato, Hiroki; Kondo, Hiroshi; Goshima, Satoshi; Tsuge, Yusuke; Kojima, Toshiaki; Watanabe, Haruo [Gifu University Hospital, Department of Radiology (Japan)

2011-02-15

176

Electrochemical dissolved oxygen removal from microfluidic streams for LOC sample pretreatment.  

PubMed

Current water quality monitoring for heavy metal contaminants largely results in analytical snapshots at a particular time and place. Therefore, we have been interested in miniaturized and inexpensive sensors suitable for long-term, real-time monitoring of the drinking water distribution grid, industrial wastewater effluents, and even rivers and lakes. Among the biggest challenges for such sensors are the issues of in-field device calibration and sample pretreatment. Previously, we have demonstrated use of coulometric stripping analysis for calibration-free determination of copper and mercury. For more negatively reduced metals, O2 reduction interferes with stripping analysis; hence, most electroanalysis techniques rely on pretreatments to remove dissolved oxygen (DO). Current strategies for portable DO removal offer limited practicality, because of their complexity, and often cause inadvertent sample alterations. Therefore, we have designed an indirect in-line electrochemical DO removal device (EDOR), utilizing a silver cathode to reduce DO in a chamber that is fluidically isolated from the sample stream by an O2-permeable membrane. The resulting concentration gradient supports passive DO diffusion from the sample stream into the deoxygenation chamber. The DO levels in the sample stream were determined by cyclic voltammetry (CV) and amperometry at a custom thin-layer cell (TLC) detector. Results show removal of 98% of the DO in a test sample at flow rates approaching 50 ?L/min and power consumption as low as 165 mW h L(-1) at steady state. Besides our specific stripping application, this device is well-suited for LOC applications where miniaturized DO removal and/or regulation are desirable. PMID:25082792

Marei, Mohamed M; Roussel, Thomas J; Keynton, Robert S; Baldwin, Richard P

2014-09-01

177

Giant Pediatric Aneurysmal Bone Cysts of the Occipital Bone: Case Report and Review of the Literature  

Microsoft Academic Search

Cranial aneurysmal bone cysts are uncommon. Cranial aneurysmal bone cysts of the occipital bone are exceedingly rare. A 2-year-old toddler with this rare cyst presented with a large space-occupying lesion of the posterior fossa, with cerebellar tonsillar herniation. The patient experienced complete recovery after total excision of the lesion. We review the literature regarding this rare presentation, and discuss the

Jacob Genizi; Srugo Isaac; Attias Dina; Ben-Sira Liat; Braun Jacob; Bamberger S. Ellen; Margalit Nevo; Constantini Shlomi

2011-01-01

178

Visual Implicit Memory Deficit and Developmental Surface Dyslexia: A Case of Early Occipital Damage  

Microsoft Academic Search

This study reports the case of EBON, a fifteen-year-old right-handed female Swedish student, who suffered an early medial\\/dorsal occipital brain lesion and showed a clearly defined pattern of developmental surface dyslexia. EBON and 17 controls were examined with within and cross-modality (visual and auditory) word stem completion tasks together with tasks requiring free-recall and recognition for visually and auditory presented

Stefan Samuelsson; Thomas R. Bogges; Thomas Karlsson

2000-01-01

179

Occipital nerve block is effective in craniofacial neuralgias but not in idiopathic persistent facial pain.  

PubMed

Occipital nerve block (ONB) has been used in several primary headache syndromes with good results. Information on its effects in facial pain is sparse. In this chart review, the efficacy of ONB using lidocaine and dexamethasone was evaluated in 20 patients with craniofacial pain syndromes comprising 8 patients with trigeminal neuralgia, 6 with trigeminal neuropathic pain, 5 with persistent idiopathic facial pain and 1 with occipital neuralgia. Response was defined as an at least 50% reduction of original pain. Mean response rate was 55% with greatest efficacy in trigeminal (75%) and occipital neuralgia (100%) and less efficacy in trigeminal neuropathic pain (50%) and persistent idiopathic facial pain (20%). The effects lasted for an average of 27 days with sustained benefits for 69, 77 and 107 days in three patients. Side effects were reported in 50%, albeit transient and mild in nature. ONBs are effective in trigeminal pain involving the second and third branch and seem to be most effective in craniofacial neuralgias. They should be considered in facial pain before more invasive approaches, such as thermocoagulation or vascular decompression, are performed, given that side effects are mild and the procedure is minimally invasive. PMID:22383125

Jürgens, T P; Müller, P; Seedorf, H; Regelsberger, J; May, A

2012-04-01

180

Recognition and management of atlanto-occipital dislocation: improving survival from an often fatal condition  

PubMed Central

Objective To provide an overview of atlanto-occipital dislocation and associated occipital condyle fractures so as to alert physicians to this rare injury and potentially improve patient outcome. The pertinent anatomy, mechanism of injury, clinical and radiologic evaluation and the management of these rare injuries are discussed in an attempt to alert physicians to this type of injury and to improve outcome. Data sources The data were obtained from a MEDLINE search of the English literature from 1966 to 1999 and the experience of 4 spine surgeons at a quaternary care acute spinal cord injury unit. Study selection Detailed anatomic and epidemiologically sound radiology studies were identified and analyzed. Only small retrospective studies or case series were available in the literature. Data extraction Valid anatomic, biomechanical and radiologic evaluation was extracted from studies. Clinical data came from limited studies and expert opinion. Data synthesis Early diagnosis is essential and is facilitated by a detailed clinical examination and strict adherence to an imaging algorithm that includes CT and MRI scanning. When the dislocation is identified, timely gentle reduction and prompt stabilization throuigh nonoperative or operative means is found to optimize patient outcome. Conclusions Atlanto-occipital dislocation should be suspected in any patient involved in a high speed motor vehicle or pedestrian collision. Once suspected, proper imaging and appropriate management of these once fatal injuries can improve survival and neurologic outcome. PMID:11764873

Fisher, Charles G.; Sun, John C.L.; Dvorak, Marcel

2001-01-01

181

Retropharyngeal pseudomeningocele formation as a traumatic atlanto-occipital dislocation complication: case report and review.  

PubMed

Retropharyngeal pseudomeningocele after atlanto-occipital dislocation is a rare complication, with only five cases described in the literature. It develops when a traumatic dural tear occurs allowing cerebrospinal fluid outflow, and it often appears associated with hydrocephalus. We present a case of a 29-year-old female who suffered a motor vehicle accident causing severe brain trauma and spinal cord injury. At hospital arrival the patient scored three points in the Glasgow Coma Scale. Admission computed tomography of the head and neck demonstrated subarachnoid hemorrhage and atlanto-occipital dislocation. Three weeks later, when impossibility to disconnect her from mechanical ventilation was noticed, a magnetic resonance imaging of the neck showed a large retropharyngeal pseudomeningocele. No radiological evidence of hydrocephalus was documented. Given the poor neurological status of the patient, with spastic quadriplegia and disability to breathe spontaneously due to bulbar-medullar injury, no invasive measure was performed to treat the pseudomeningocele. Retropharyngeal pseudomeningocele after atlanto-occipital dislocation should be managed by means of radiological brain study in order to assess for the presence of hydrocephalus, since these two pathologies often appear associated. If allowed by neurological condition of the patient, shunting procedures such as ventriculo-peritoneal or lumbo-peritoneal shunt placement may be helpful for the treatment of the pseudomeningocele, regardless of craniocervical junction management. PMID:17973127

Gutiérrez-González, Raquel; Boto, Gregorio R; Pérez-Zamarrón, Alvaro; Rivero-Garvía, Mónica

2008-09-01

182

Traumatic retropharyngeal pseudomeningocele with atlanto-occipital dislocation in a neurologically intact patient.  

PubMed

Traumatic retropharyngeal pseudomeningoceles occur rarely, are associated with severe trauma, and have been reported in patients with significant neurologic deficits at presentation. We report the rare occurrence of a pseudomeningocele following a high-speed motor vehicle accident. Neurological examination showed the patient to be briskly following commands, with intact cranial nerve, motor, and sensory function. CT/MR imaging showed subarachnoid hemorrhage involving the interpeduncular cistern, a clivus fracture, a right occipital condyle fracture, an atlanto-occipital subluxation, aortic arch transection (stable and contained on CT angiogram), multiple rib fractures on the right side with associated pneumothorax, hemothorax and pulmonary contusions. His cervical spine was stabilized in a halo. He was subsequently managed in the intensive care unit and remained neurologically intact. A repeat MRI showed the interval development of a 2×1.5 cm pseudomeningocele at the craniocervical junction medial to the left occipital condyle communicating with the left anterolateral aspect of the spinal canal. Traumatic pseudomeningoceles are associated with large deceleration forces at the time of injury and are usually associated with significant neurologic deficits at presentation. However, they can arise and give rise to symptoms in a delayed fashion in trauma patients who are neurologically intact at initial presentation. PMID:24300004

Mathews, M S; Owen, C M; Hasso, A N; Binder, D K

2007-12-31

183

Retropharyngeal pseudomeningocele formation as a traumatic atlanto-occipital dislocation complication: case report and review  

PubMed Central

Retropharyngeal pseudomeningocele after atlanto-occipital dislocation is a rare complication, with only five cases described in the literature. It develops when a traumatic dural tear occurs allowing cerebrospinal fluid outflow, and it often appears associated with hydrocephalus. We present a case of a 29-year-old female who suffered a motor vehicle accident causing severe brain trauma and spinal cord injury. At hospital arrival the patient scored three points in the Glasgow Coma Scale. Admission computed tomography of the head and neck demonstrated subarachnoid hemorrhage and atlanto-occipital dislocation. Three weeks later, when impossibility to disconnect her from mechanical ventilation was noticed, a magnetic resonance imaging of the neck showed a large retropharyngeal pseudomeningocele. No radiological evidence of hydrocephalus was documented. Given the poor neurological status of the patient, with spastic quadriplegia and disability to breathe spontaneously due to bulbar-medullar injury, no invasive measure was performed to treat the pseudomeningocele. Retropharyngeal pseudomeningocele after atlanto-occipital dislocation should be managed by means of radiological brain study in order to assess for the presence of hydrocephalus, since these two pathologies often appear associated. If allowed by neurological condition of the patient, shunting procedures such as ventriculo-peritoneal or lumbo-peritoneal shunt placement may be helpful for the treatment of the pseudomeningocele, regardless of craniocervical junction management. PMID:17973127

Boto, Gregorio R.; Pérez-Zamarrón, Álvaro; Rivero-Garvía, Mónica

2007-01-01

184

Enhanced Awareness Followed Reversible Inhibition of Human Visual Cortex: A Combined TMS, MRS and MEG Study  

PubMed Central

This series of experiments investigated the neural basis of conscious vision in humans using a form of transcranial magnetic stimulation (TMS) known as continuous theta burst stimulation (cTBS). Previous studies have shown that occipital TMS, when time-locked to the onset of visual stimuli, can induce a phenomenon analogous to blindsight in which conscious detection is impaired while the ability to discriminate ‘unseen’ stimuli is preserved above chance. Here we sought to reproduce this phenomenon using offline occipital cTBS, which has been shown to induce an inhibitory cortical aftereffect lasting 45–60 minutes. Contrary to expectations, our first experiment revealed the opposite effect: cTBS enhanced conscious vision relative to a sham control. We then sought to replicate this cTBS-induced potentiation of consciousness in conjunction with magnetoencephalography (MEG) and undertook additional experiments to assess its relationship to visual cortical excitability and levels of the inhibitory neurotransmitter ?-aminobutyric acid (GABA; via magnetic resonance spectroscopy, MRS). Occipital cTBS decreased cortical excitability and increased regional GABA concentration. No significant effects of cTBS on MEG measures were observed, although the results provided weak evidence for potentiation of event related desynchronisation in the ? band. Collectively these experiments suggest that, through the suppression of noise, cTBS can increase the signal-to-noise ratio of neural activity underlying conscious vision. We speculate that gating-by-inhibition in the visual cortex may provide a key foundation of consciousness. PMID:24956195

Allen, Christopher P. G.; Dunkley, Benjamin T.; Muthukumaraswamy, Suresh D.; Edden, Richard; Evans, C. John; Sumner, Petroc; Singh, Krish D.; Chambers, Christopher D.

2014-01-01

185

Effects of Visual Cortex Activation on the Nociceptive Blink Reflex in Healthy Subjects  

PubMed Central

Bright light can cause excessive visual discomfort, referred to as photophobia. The precise mechanisms linking luminance to the trigeminal nociceptive system supposed to mediate this discomfort are not known. To address this issue in healthy human subjects we modulated differentially visual cortex activity by repetitive transcranial magnetic stimulation (rTMS) or flash light stimulation, and studied the effect on supraorbital pain thresholds and the nociceptive-specific blink reflex (nBR). Low frequency rTMS that inhibits the underlying cortex, significantly decreased pain thresholds, increased the 1st nBR block ipsi- and contralaterally and potentiated habituation contralaterally. After high frequency or sham rTMS over the visual cortex, and rMS over the right greater occipital nerve we found no significant change. By contrast, excitatory flash light stimulation increased pain thresholds, decreased the 1st nBR block of ipsi- and contralaterally and increased habituation contralaterally. Our data demonstrate in healthy subjects a functional relation between the visual cortex and the trigeminal nociceptive system, as assessed by the nociceptive blink reflex. The results argue in favour of a top-down inhibitory pathway from the visual areas to trigemino-cervical nociceptors. We postulate that in normal conditions this visuo-trigeminal inhibitory pathway may avoid disturbance of vision by too frequent blinking and that hypoactivity of the visual cortex for pathological reasons may promote headache and photophobia. PMID:24936654

Sava, Simona L.; de Pasqua, Victor; Magis, Delphine; Schoenen, Jean

2014-01-01

186

Vestibular function in the temporal and parietal cortex: distinct velocity and inertial processing pathways  

PubMed Central

A number of behavioral and neuroimaging studies have reported converging data in favor of a cortical network for vestibular function, distributed between the temporo-parietal cortex and the prefrontal cortex in the primate. In this review, we focus on the role of the cerebral cortex in visuo-vestibular integration including the motion sensitive temporo-occipital areas i.e., the middle superior temporal area (MST) and the parietal cortex. Indeed, these two neighboring cortical regions, though they both receive combined vestibular and visual information, have distinct implications in vestibular function. In sum, this review of the literature leads to the idea of two separate cortical vestibular sub-systems forming (1) a velocity pathway including MST and direct descending pathways on vestibular nuclei. As it receives well-defined visual and vestibular velocity signals, this pathway is likely involved in heading perception and rapid top-down regulation of eye/head coordination and (2) an inertial processing pathway involving the parietal cortex in connection with the subcortical vestibular nuclei complex responsible for velocity storage integration. This vestibular cortical pathway would be implicated in high-order multimodal integration and cognitive functions, including world space and self-referential processing. PMID:25071481

Ventre-Dominey, Jocelyne

2014-01-01

187

Evidence for premotor cortex activity during dynamic visuospatial imagery from single-trial functional magnetic resonance imaging and event-related slow cortical potentials.  

PubMed

A strong correspondence has been repeatedly observed between actually performed and mentally imagined object rotation. This suggests an overlap in the brain regions involved in these processes. Functional neuroimaging studies have consistently revealed parietal and occipital cortex activity during dynamic visuospatial imagery. However, results concerning the involvement of higher-order cortical motor areas have been less consistent. We investigated if and when premotor structures are active during processing of a three-dimensional cube comparison task that requires dynamic visuospatial imagery. In order to achieve a good temporal and spatial resolution, single-trial functional magnetic resonance imaging (fMRI) and scalp-recorded event-related slow cortical potentials (SCPs) were recorded from the same subjects in two separate measurement sessions. In order to reduce inter-subject variability in brain activity due to individual differences, only male subjects (n = 13) with high task-specific ability were investigated. Functional MRI revealed consistent bilateral activity in the occipital (Brodmann area BA18/19) and parietal cortex (BA7), in lateral and medial premotor areas (BA6), the dorsolateral prefrontal cortex (BA9), and the anterior insular cortex. The time-course of SCPs indicated that task-related activity in these areas commenced approximately 550-650 ms after stimulus presentation and persisted until task completion. These results provide strong and consistent evidence that the human premotor cortex is involved in dynamic visuospatial imagery. PMID:11467902

Lamm, C; Windischberger, C; Leodolter, U; Moser, E; Bauer, H

2001-08-01

188

Unusual MRI appearance of diffuse subcortical heterotopia or "double cortex" in two children.  

PubMed Central

Two children with mild epilepsy and learning and behaviour problems had magnetic resonance imaging (MRI) scans showing an almost identical generalised disorders of neuronal migration. Their computer tomography (CT) scans showed abnormal hypodense white matter. The MRI showed a four layered appearance of the cerebral parenchyma extending from the frontal to the occipital region. There was a normal appearance to the white matter in the periventricular region which had an abnormally smooth junction with a thick diffuse layer of heterotopic grey matter. This was surrounded by a thin layer of white matter which had normal digitations with the overlying cortex. The appearance of the overlying cortex was normal. These and other recently described cases broaden the concept of generalised disorders of neuronal migration and illustrate that it is possible to have a generalised cerebral malformation with few clinical consequences. Images PMID:2118172

Livingston, J H; Aicardi, J

1990-01-01

189

Afferent and efferent connections of the dorsolateral corticoid area and a comparison with connections of the temporo-parieto-occipital area in the pigeon (Columba livia).  

PubMed

The dorsolateral corticoid area (CDL) in the pigeon telencephalon is a thin, superficial part of the caudal pallium adjoining the medially situated hippocampal formation. To determine the connectivity of CDL, and to distinguish CDL from the rostrally adjacent temporo-parieto-occipital area (TPO), injections of neural tracers were made into the caudal superficial pallium at various rostrocaudal levels. The results showed that injections caudal to A 6.75 (Karten and Hodos [1967] Baltimore: Johns Hopkins University Press) gave rise to reciprocal connections with subdivisions of the hippocampal formation, TPO, piriform cortex, posterior pallial amygdala, caudoventral nidopallium, densocellular part of the hyperpallium, lateral hyperpallium, frontolateral nidopallium, and lateral intermediate nidopallium. Of these, the hippocampal formation showed very strong connectivity with CDL, and projection fibers from CDL clearly separated the dorsomedial region of the hippocampal formation into lateral and medial portions. CDL projected directly to the olfactory bulb, but did not receive projections from it. In the diencephalon, CDL received efferents from a dorsal region of the medial part of the anterior dorsolateral nucleus of the thalamus, subrotundal nucleus, and internal paramedian nucleus of the thalamus. These findings suggest that CDL in the pigeon belongs to the limbic pallium and that in some respects it may be comparable to the mammalian cingulate cortex. In contrast, injections of tracers into the pallial surface at or rostral to A 7.00 showed marked differences in the pattern of both anterograde and retrograde labeling from that resulting from injections caudal to A 6.50, thereby indicating the approximate level of transition from CDL to TPO. PMID:15776448

Atoji, Yasuro; Wild, J Martin

2005-05-01

190

mPLR-Loc: An adaptive decision multi-label classifier based on penalized logistic regression for protein subcellular localization prediction.  

PubMed

Proteins located in appropriate cellular compartments are of paramount importance to exert their biological functions. Prediction of protein subcellular localization by computational methods is required in the post-genomic era. Recent studies have been focusing on predicting not only single-location proteins but also multi-location proteins. However, most of the existing predictors are far from effective for tackling the challenges of multi-label proteins. This article proposes an efficient multi-label predictor, namely mPLR-Loc, based on penalized logistic regression and adaptive decisions for predicting both single- and multi-location proteins. Specifically, for each query protein, mPLR-Loc exploits the information from the Gene Ontology (GO) database by using its accession number (AC) or the ACs of its homologs obtained via BLAST. The frequencies of GO occurrences are used to construct feature vectors, which are then classified by an adaptive decision-based multi-label penalized logistic regression classifier. Experimental results based on two recent stringent benchmark datasets (virus and plant) show that mPLR-Loc remarkably outperforms existing state-of-the-art multi-label predictors. In addition to being able to rapidly and accurately predict subcellular localization of single- and multi-label proteins, mPLR-Loc can also provide probabilistic confidence scores for the prediction decisions. For readers' convenience, the mPLR-Loc server is available online (http://bioinfo.eie.polyu.edu.hk/mPLRLocServer). PMID:25449328

Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

2015-03-15

191

Increased Visual Stimulation Systematically Decreases Activity in Lateral Intermediate Cortex.  

PubMed

Previous studies have attributed multiple diverse roles to the posterior superior temporal cortex (STC), both visually driven and cognitive, including part of the default mode network (DMN). Here, we demonstrate a unifying property across this multimodal region. Specifically, the lateral intermediate (LIM) portion of STC showed an unexpected feature: a progressively decreasing fMRI response to increases in visual stimulus size (or number). Such responses are reversed in sign, relative to well-known responses in classic occipital temporal visual cortex. In LIM, this "reversed" size function was present across multiple object categories and retinotopic eccentricities. Moreover, we found a significant interaction between the LIM size function and the distribution of subjects' attention. These findings suggest that LIM serves as a part of the DMN. Further analysis of functional connectivity, plus a meta-analysis of previous fMRI results, suggests that LIM is a heterogeneous area including different subdivisions. Surprisingly, analogous fMRI tests in macaque monkeys did not reveal a clear homolog of LIM. This interspecies discrepancy supports the idea that self-referential thinking and theory of mind are more prominent in humans, compared with monkeys. PMID:25480358

Nasr, Shahin; Stemmann, Heiko; Vanduffel, Wim; Tootell, Roger B H

2014-12-01

192

Magnetic stimulation of the left visual cortex impairs expert word recognition.  

PubMed

One of the hallmarks of expert reading is the ability to identify arrays of several letters quickly and in parallel. Such length-independent reading has only been found for word stimuli appearing in the right visual hemifield (RVF). With left hemifield presentation (LVF), response times increase as a function of word length. Here we investigated the comparative efficiency with which the two hemispheres are able to recognize visually presented words, as measured by word length effects. Repetitive transcranial magnetic stimulation (rTMS) of the left occipital cortex disrupted expert processing of the RVF such that a length effect was created (Experiment 1). Right occipital rTMS, on the other hand, had no such effect on RVF words and nor did it modulate the length effect already present in the LVF. Experiment 2 explored the time course of these TMS-induced effects by applying single pulses of TMS at various stimulus-onset asynchronies for the same task. We replicated the TMS-induced length effect for RVF words, but only when a single pulse was applied to the left visual cortex 80 msec after target presentation. This is the first demonstration of TMS-induced impairment producing a word length effect, and as such confirms the specialization of the left hemisphere in word recognition. It is likely that anatomical differences in the pathway linking retinal input to higher level cortical processing drive this effect. PMID:17014378

Skarratt, Paul A; Lavidor, Michal

2006-10-01

193

Occipital Neuralgia  

MedlinePLUS

... of headache characterized by piercing, throbbing, or electric-shock-like chronic pain in the upper neck, back ... condition. Many individuals will improve with therapy involving heat, rest, anti-inflammatory medications, and muscle relaxants. Recovery ...

194

Pathology Case Study: Mental Status Changes and a Severe Occipital Headache  

NSDL National Science Digital Library

This is a case study presented by the University of Pittsburgh Department of Pathology in which a 32-year-old man with symptoms of an upper respiratory infection presented himself to the hospital with mental status changes and a severe occipital headache of two days duration. Visitors are given both the microscopic description and radiology results, including images, and are given the opportunity to diagnose the patient. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose disease. It is also a helpful site for educators to use to introduce or test student learning in neuropathology.

Grossman, Robert I.

195

LOC401317, a p53-Regulated Long Non-Coding RNA, Inhibits Cell Proliferation and Induces Apoptosis in the Nasopharyngeal Carcinoma Cell Line HNE2  

PubMed Central

Recent studies have revealed that long non-coding RNAs participate in all steps of cancer initiation and progression by regulating protein-coding genes at the epigenetic, transcriptional, and post-transcriptional levels. Long non-coding RNAs are in turn regulated by other genes, forming a complex regulatory network. The regulation networks between the p53 tumor suppressor and these RNAs in nasopharyngeal carcinoma remains unclear. The aims of this study were to investigate the regulatory roles of the TP53 gene in regulating long non-coding RNA expression profiles and to study the function of a TP53-regulated long non-coding RNA (LOC401317) in the nasopharyngeal carcinoma cell line HNE2. Long non-coding RNA expression profiling indicated that 133 long non-coding RNAs were upregulated in the human NPC cell line HNE2 cells following TP53 overexpression, while 1057 were downregulated. Among these aberrantly expressed long non-coding RNAs, LOC401317 was the most significantly upregulated one. Further studies indicated that LOC401317 is directly regulated by p53 and that ectopic expression of LOC401317 inhibits HNE2 cell proliferation in vitro and in vivo by inducing cell cycle arrest and apoptosis. LOC401317 inhibited cell cycle progression by increasing p21 expression and decreasing cyclin D1 and cyclin E1 expression and promoted apoptosis through the induction of poly(ADP-ribose) polymerase and caspase-3 cleavage. Collectively, these results suggest that LOC401317 is directly regulated by p53 and exerts antitumor effects in HNE2 nasopharyngeal carcinoma cells. PMID:25422887

Gong, Zhaojian; Zhang, Shanshan; Zeng, Zhaoyang; Wu, Hanjiang; Yang, Qian; Xiong, Fang; Shi, Lei; Yang, Jianbo; Zhang, Wenling; Zhou, Yanhong; Zeng, Yong; Li, Xiayu; Xiang, Bo; Peng, Shuping; Zhou, Ming; Li, Xiaoling; Tan, Ming; Li, Yong; Xiong, Wei; Li, Guiyuan

2014-01-01

196

LOC387715/HTRA1 gene polymorphisms and susceptibility to age-related macular degeneration: A HuGE review and meta-analysis  

PubMed Central

Purpose To examine the association of age-related macular degeneration (AMD) with HtrA serine peptidase 1 (HTRA1) gene rs11200638 G?A polymorphism and LOC387715/ ARMS2 gene rs10490924 G?T polymorphisms, and to evaluate the magnitude of the gene effect and the possible genetic mode of action. Methods We searched the US National Library of Medicine’s PubMed, Embase, OMIM, ISI Web of Science, and CNKI databases in a systematic manner to retrieve all genetic association studies on the HTRA1 (rs11200638) and LOC387715/ ARMS2 (rs10490924) gene polymorphisms and AMD. We performed a meta-analysis conducted with Stata software, version 9.0. Results Individuals who carried the AA and AG genotypes of HTRA1 gene rs11200638 G?A polymorphism had 2.243 and 8.669 times the risk of developing AMD, respectively, when compared with those who carry the GG genotype. Individuals carrying the TT and TG genotypes of LOC387715/ ARMS2 gene rs10490924 G?T polymorphism had 7.512 and 2.353 times the risk of developing AMD, respectively, compared with those who carry GG genotype. These results suggested a “moderate” codominant, multiplicative genetic mode; that is, both HTRA1 rs11200638 G?A polymorphism and LOC387715/ARMS2 rs10490924 G?T polymorphism play important roles in the pathogenesis of AMD. We found no evidence of publication bias. Between-study heterogeneity was found in both allele-based analysis and genotype-based analysis. Conclusions HTRA1 rs11200638 G?A polymorphism and LOC387715/ARMS2 rs10490924 G?T polymorphism play important roles in AMD. Gene-gene and gene-environmental interactions, as well as precise mechanisms underlying common variants in the HTRA1 gene and LOC387715/ ARMS2 gene, potentially increase the risk of AMD and need further exploration. PMID:21031019

Tong, Yu; Liao, Jing; Zhang, Yuan; Zhou, Jing; Zhang, Hengyu

2010-01-01

197

Reduced Resting-State Functional Connectivity of the Somatosensory Cortex Predicts Psychopathological Symptoms in Women with Bulimia Nervosa  

PubMed Central

Background: Alterations in the resting-state functional connectivity (rs-FC) of several brain networks have been demonstrated in eating disorders. However, very few studies are currently available on brain network dysfunctions in bulimia nervosa (BN). The somatosensory network is central in processing body-related stimuli and it may be altered in BN. The present study therefore aimed to investigate rs-FC in the somatosensory network in bulimic women. Methods: Sixteen medication-free women with BN (age?=?23?±?5?years) and 18 matched controls (age?=?23?±?3?years) underwent a functional magnetic resonance resting-state scan and assessment of eating disorder symptoms. Within-network and seed-based functional connectivity analyses were conducted to assess rs-FC within the somatosensory network and to other areas of the brain. Results: Bulimia nervosa patients showed a decreased rs-FC both within the somatosensory network (t?=?9.0, df?=?1, P?=?0.005) and with posterior cingulate cortex and two visual areas (the right middle occipital gyrus and the right cuneus) (P?=?0.05 corrected for multiple comparison). The rs-FC of the left paracentral lobule with the right middle occipital gyrus correlated with psychopathology measures like bulimia (r?=??0.4; P?=?0.02) and interoceptive awareness (r?=??0.4; P?=?0.01). Analyses were conducted using age, BMI (body mass index), and depressive symptoms as covariates. Conclusion: Our findings show a specific alteration of the rs-FC of the somatosensory cortex in BN patients, which correlates with eating disorder symptoms. The region in the right middle occipital gyrus is implicated in body processing and is known as extrastriate body area (EBA). The connectivity between the somatosensory cortex and the EBA might be related to dysfunctions in body image processing. The results should be considered preliminary due to the small sample size. PMID:25136302

Lavagnino, Luca; Amianto, Federico; D’Agata, Federico; Huang, Zirui; Mortara, Paolo; Abbate-Daga, Giovanni; Marzola, Enrica; Spalatro, Angela; Fassino, Secondo; Northoff, Georg

2014-01-01

198

The auditory cortex  

Microsoft Academic Search

The division of the auditory cortex into various fields, functional aspects of these fields, and neuronal coding in the primary\\u000a auditory cortical field (AI) are reviewed with stress on features that may be common to mammals. On the basis of 14 topographies\\u000a and clustered distributions of neuronal response characteristics in the primary auditory cortical field, a hypothesis is developed\\u000a of

G. Ehret

1997-01-01

199

Transcranial magnetic stimulation of the visual cortex induces somatotopically organized qualia in blind subjects.  

PubMed

After loss of a particular sensory channel, the deprived cortex can be activated by inputs from other sensory modalities. It is not known whether activation of the rewired cortex evokes subjective experiences characteristic of that cortex or consistent with the rerouted sensory information. In a previous study, blind subjects were trained to perform visual tasks with a tongue display unit, a sensory substitution device that translates visual displays into electrotactile tongue stimulation. This cross-modal sensory stimulation activated their visual cortices. We now extend this finding by using transcranial magnetic stimulation to examine the perceptual correlates of training-induced plastic responses. We find that blind subjects proficient with the use of the tongue display unit report somatopically organized tactile sensations that are referred to the tongue when transcranial magnetic stimulation is applied over the occipital cortex. No such sensations were evoked in trained, blindfolded, seeing control subjects who performed the sensory substitution task equally well. These data show that the perceptual correlate of activity in a given cortical area reflects the characteristics of its novel sensory input source. PMID:16916936

Kupers, Ron; Fumal, Arnaud; de Noordhout, Alain Maertens; Gjedde, Albert; Schoenen, Jean; Ptito, Maurice

2006-08-29

200

Transcranial magnetic stimulation of the visual cortex induces somatotopically organized qualia in blind subjects  

PubMed Central

After loss of a particular sensory channel, the deprived cortex can be activated by inputs from other sensory modalities. It is not known whether activation of the rewired cortex evokes subjective experiences characteristic of that cortex or consistent with the rerouted sensory information. In a previous study, blind subjects were trained to perform visual tasks with a tongue display unit, a sensory substitution device that translates visual displays into electrotactile tongue stimulation. This cross-modal sensory stimulation activated their visual cortices. We now extend this finding by using transcranial magnetic stimulation to examine the perceptual correlates of training-induced plastic responses. We find that blind subjects proficient with the use of the tongue display unit report somatopically organized tactile sensations that are referred to the tongue when transcranial magnetic stimulation is applied over the occipital cortex. No such sensations were evoked in trained, blindfolded, seeing control subjects who performed the sensory substitution task equally well. These data show that the perceptual correlate of activity in a given cortical area reflects the characteristics of its novel sensory input source. PMID:16916936

Kupers, Ron; Fumal, Arnaud; de Noordhout, Alain Maertens; Gjedde, Albert; Schoenen, Jean; Ptito, Maurice

2006-01-01

201

Contributions of pitch and bandwidth to sound-induced enhancement of visual cortex excitability in humans.  

PubMed

Multisensory interactions have been documented within low-level, even primary, cortices and at early post-stimulus latencies. These effects are in turn linked to behavioral and perceptual modulations. In humans, visual cortex excitability, as measured by transcranial magnetic stimulation (TMS) induced phosphenes, can be reliably enhanced by the co-presentation of sounds. This enhancement occurs at pre-perceptual stages and is selective for different types of complex sounds. However, the source(s) of auditory inputs effectuating these excitability changes in primary visual cortex remain disputed. The present study sought to determine if direct connections between low-level auditory cortices and primary visual cortex are mediating these kinds of effects by varying the pitch and bandwidth of the sounds co-presented with single-pulse TMS over the occipital pole. Our results from 10 healthy young adults indicate that both the central frequency and bandwidth of a sound independently affect the excitability of visual cortex during processing stages as early as 30 msec post-sound onset. Such findings are consistent with direct connections mediating early-latency, low-level multisensory interactions within visual cortices. PMID:23419789

Spierer, Lucas; Manuel, Aurelie L; Bueti, Domenica; Murray, Micah M

2013-01-01

202

Non-holistic coding of objects in lateral occipital complex with and without attention.  

PubMed

A fundamental issue in visual cognition is whether high-level visual areas code objects in a part-based or a view-based (holistic) format. Previous behavioral and neuroimaging studies that examined the viewpoint invariance of object recognition have yielded ambiguous results, providing evidence for either type of representational format. A critical factor distinguishing the two formats could be the availability of attentional resources, as a number of priming studies have found greater viewpoint invariance for attended compared to unattended objects. It has therefore been suggested that the activation of part-based representations requires attention, whereas the activation of holistic representations occurs automatically irrespective of attention. Using functional magnetic resonance imaging in combination with a novel multivariate pattern analysis approach, the present study probed the format of object representations in human lateral occipital complex and its dependence on attention. We presented human participants with intact and half-split versions of objects that were either attended or unattended. Cross-classifying between intact and split objects, we found that the object-related information coded in activation patterns of intact objects is fully preserved in the patterns of split objects and vice versa. Importantly, the generalization between intact and split objects did not depend on attention. We conclude that lateral occipital complex codes objects in a non-holistic format, both in the presence and absence of attention. PMID:25512039

Guggenmos, Matthias; Thoma, Volker; Cichy, Radoslaw Martin; Haynes, John-Dylan; Sterzer, Philipp; Richardson-Klavehn, Alan

2015-02-15

203

Distinctive Menkes disease variant with occipital horns: Delineation of natural history and clinical phenotype  

SciTech Connect

To delineate further the clinical spectrum of Menkes disease, an X-linked recessive disorder of copper transport, we studied 4 related males, ranging in age from 4-38 years, with a unique phenotype that combines manifestations of classical and mild Menkes disease and occipital horn syndrome (OHS). The propositus, an 18-year-old man, was evaluated following an intracerebral hemorrhage at age 15 years and was noted to have marked hypotonia, motor delay with mental retardation, bladder diverticula, failure to thrive, and diarrhea from infancy; seizures from age 3 years; and abnormal hair (pili torti) and face, cutis laxa, and multiple joint dislocations. Radiographic abnormalities included occipital exostoses, tortuous cerebral blood vessels with multiple branch occlusions, and hammer-shaped clavicles. Biochemical studies demonstrated reduced copper and ceruloplasmin levels in serum, and abnormal plasma catecholamine ratios. We reported previously the molecular defect in this family, a splice-site mutation that predicts formation of approximately 20% of the normal Menkes gene product. Here, we detail the clinical course and physical features and radiographic findings in these 4 individuals, and compare their phenotype with classical and mild Menkes and OHS. Unusual Menkes disease variants such as this may escape recognition due to anomalies that appear inconsistent with the diagnosis, particularly prolonged survival and later onset of seizures. Males with mental retardation and connective tissue abnormalities should be evaluated for biochemical evidence of defective copper transport. 28 refs., 8 figs.

Proud, V.K.; Mussell, H.G.; Percy, A.K. [Univ. of Alabama School of Medicine, Birmingham, AL (United States)] [and others] [Univ. of Alabama School of Medicine, Birmingham, AL (United States); and others

1996-10-02

204

Radiation-induced malignant fibrous histiocytoma of the occipital: a case report  

PubMed Central

Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. Effective treatment modality is surgical resection with wide margins, but its rate of recurrence and metastasis is still high. Early detection and complete excision of the tumor is necessary. A MFH of the occipital developed in a 51-year-old woman eight years after surgery and radiation for medulloblastoma of the cerebellar vermis. The secondary neoplasm arose at the site of tumor resection within the irradiated field, and was resected. The development of sarcomas is a recognized complication of radiation therapy. The final diagnosis after the operation was MFH. Radiation-induced sarcoma (RIS) is well known, but radiation-induced MFH is relatively rare in the head and neck region, especially in the occipital. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by computerized tomography (CT) and magnetic resonance imaging (MRI) and appreciation of the expected latency period may help in providing the diagnosis of RIS. PMID:24742094

2014-01-01

205

PAPER www.rsc.org/loc | Lab on a Chip Programmable assembly of a metabolic pathway enzyme in a pre-packaged  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip Programmable assembly of a metabolic pathway enzyme in a pre report a biofunctionalization strategy for the assembly of catalytically active enzymes within and temporally defined sites. The enzyme of a bacterial metabolic pathway, S-adenosylhomocysteine nucleosidase

Rubloff, Gary W.

206

Development of an integrated bio-microfluidic package with micro-valves and reservoirs for a DNA lab on a chip (LOC) application  

Microsoft Academic Search

A bio-microfluidic package has been developed with integrated reservoir and valves for DNA (deoxyribonucleic acid) lab on a chip (LOC) application. A polymer material, PDMS (polydimethylsiloxane) is used for encapsulating the DNA chip. Channels, reservoirs and valves are formed on the PDMS material by casting method. A mold fabricated in acrylic material is used. A double sided adhesive tape is

Ling Xie; Ser Choong Chong; C. S. Premachandran; M. Chew; Uppili Raghavan

2006-01-01

207

Design, Integration and Testing of Fluidic Dispensing Control Valve into a DNA\\/RNA Sample Preparation Micro fluidic Package for Lab on a Chip (LOC) Applications  

Microsoft Academic Search

A bio-microfluidic package has been developed with integrated reservoir and valves for DNA (deoxyribonucleic acid) lab on a chip (LOC) application. A polymer material, PDMS (polydimethylsiloxane) is used for encapsulating the DNA chip. Channels, reservoirs and valves are formed on the PDMS material by casting method. A double sided adhesive tape is used to bond PDMS substrates and DNA chip.

Ling Xie; C. S. Premachandran; Ser Choong Chong; Michelle Chew

2007-01-01

208

HybridGO-Loc: Mining Hybrid Features on Gene Ontology for Predicting Subcellular Localization of Multi-Location Proteins  

PubMed Central

Protein subcellular localization prediction, as an essential step to elucidate the functions in vivo of proteins and identify drugs targets, has been extensively studied in previous decades. Instead of only determining subcellular localization of single-label proteins, recent studies have focused on predicting both single- and multi-location proteins. Computational methods based on Gene Ontology (GO) have been demonstrated to be superior to methods based on other features. However, existing GO-based methods focus on the occurrences of GO terms and disregard their relationships. This paper proposes a multi-label subcellular-localization predictor, namely HybridGO-Loc, that leverages not only the GO term occurrences but also the inter-term relationships. This is achieved by hybridizing the GO frequencies of occurrences and the semantic similarity between GO terms. Given a protein, a set of GO terms are retrieved by searching against the gene ontology database, using the accession numbers of homologous proteins obtained via BLAST search as the keys. The frequency of GO occurrences and semantic similarity (SS) between GO terms are used to formulate frequency vectors and semantic similarity vectors, respectively, which are subsequently hybridized to construct fusion vectors. An adaptive-decision based multi-label support vector machine (SVM) classifier is proposed to classify the fusion vectors. Experimental results based on recent benchmark datasets and a new dataset containing novel proteins show that the proposed hybrid-feature predictor significantly outperforms predictors based on individual GO features as well as other state-of-the-art predictors. For readers' convenience, the HybridGO-Loc server, which is for predicting virus or plant proteins, is available online at http://bioinfo.eie.polyu.edu.hk/HybridGoServer/. PMID:24647341

Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

2014-01-01

209

Word Recognition in Auditory Cortex  

ERIC Educational Resources Information Center

Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

DeWitt, Iain D. J.

2013-01-01

210

An Anatomical Variation of the Lesser Occipital Nerve in the “Carefree part” of the Posterior Triangle  

PubMed Central

The occurrence of the lesser occipital nerve (LON) at an anomalous location in the “carefree part” within the posterior triangle has been seldom reported in the literature. We are reporting a rare case of location of the LON in the “carefree part” of the posterior triangle, in a 55-year-old formalin embalmed male cadaver. LON, after emerging from the posterior margin of the sternomastoid muscle (SM), ran obliquely towards the trapezius muscle. Here, it hooked around the unusual separated muscle fasciculus of the trapezius, 7.5 cm below the superior nuchal line. Further, LON gave contributions to spinal accessory nerve (SAN); one deep into the SM and another one in the posterior triangle. The knowledge on the unusual location and course of the LON and its contribution to the SAN is significantly important while an anaesthetic blockade is being performed for the management of a cervicogenic headache and a super selective radical neck dissection. PMID:24959430

Sirasanagandla, Srinivasa Rao; Nayak, Satheesha B; Rao KG, Mohandas; Patil, Jyothsna

2014-01-01

211

Intradiploic occipital pseudomeningocele in a patient with remote history of surgical treatment of Chiari malformation.  

PubMed

An intradiploic CSF pseudocyst is a rare entity that has been described in association with trauma, as a sequela of untreated hydrocephalus, or occasionally as a congenital finding in older adults. The authors present the case of a woman with a remote history of a posterior fossa intradural procedure, in which she underwent Chiari malformation decompression, Silastic substitute-assisted duraplasty, and occipitocervical fusion; she presented 19 years later with recurrent symptoms of Chiari malformation. She was found to have an occipital intradiploic pseudomeningocele, arising within her dorsal occipitocervical fusion mass and resulting in dorsal hindbrain compression. She underwent a posterior fossa decompression and revision of her failed duraplasty, and she had a good recovery. This case demonstrates intradiploic CSF pseudomeningocele as a rare potential delayed complication of an intradural procedure for the treatment of Chiari malformation with occipitocervical fusion. PMID:25147975

Mahaney, Kelly B; Menezes, Arnold H

2014-11-01

212

The Magnetoencephalography correlate of EEG POSTS (Positive Occipital Sharp Transients of Sleep)  

PubMed Central

Purpose In contrast to EEG, which has guidelines for interpretation and a plethora of textbooks, the full range of activity seen in Magnetoencephalography (MEG) has not been fleshed out. Currently, magnetoencephalographers apply criteria for EEG waveforms to MEG signals based on an assumption that MEG activity should have morphology that is similar to EEG. The purpose of this paper is to show the characteristic MEG profile of Positive Occipital Sharp Transients of Sleep (POSTS) Method Simultaneous MEG-EEG recordings of two cases are shown. Result In the both cases, the morphological features of POSTS in MEG vary, and sometimes mimic epileptic spikes. Conclusion This report raises a caution that a normal variant may have an even more epileptic appearance on MEG than on EEG. Employing the simultaneously recorded EEG to avoid misinterpretation of spikey-looking POSTS in MEG is a natural and prudent practice. PMID:23733086

Kakisaka, Yosuke; Wang, Zhong I.; Enatsu, Rei; Dubarry, Anne-Sophie; Mosher, John C.; Alexopoulos, Andreas V.; Burgess, Richard C.

2014-01-01

213

Variations in the squamous part of the occipital bone in medieval and contemporary cranial series from Bulgaria.  

PubMed

The squamous part of the occipital bone is a place of many different variations. They are a result of faulty ossification in the occipital squama or due to the presence of sutural bones in the lambda region. As their differentiation is intricate because of the various criteria used, the issue of their recognition in the adult skull still remains difficult even though they can be clearly distinguished at a younger age. The aim of the present study was to compare the frequency of interparietal, preinterparietal and sutural bones in the lambda region in medieval male and female cranial series as well as between medieval and contemporary male series from Bulgaria. We also discuss the development of the occipital squama in order to set clearer criteria for further differentiation of such variations in the adult skull. In the reviewed 3 cranial series, the variations in the squamous portion of the occipital bone were observed with a low frequency. The incidence of preinterparietal bones was more common than the interparietal ones. The sutural bones in the lambda region were numerous in the series. No statistically significant sex or intergroup differences were established. So even if these anatomical variations are relatively rare, the understanding of them is of significance for many disciplines like anthropology, comparative and developmental anatomy, clinical and forensic medicine. PMID:25448900

Nikolova, S; Toneva, D; Yordanov, Y; Lazarov, N

2014-11-01

214

Panayiotopoulos syndrome: An important childhood autonomic epilepsy to be differentiated from occipital epilepsy and acute non-epileptic disorders  

Microsoft Academic Search

Panayiotopoulos syndrome is a common multifocal autonomic childhood epileptic disorder with significant clinical, pathophysiological and management implications. It affects otherwise normal children with onset at around 3–6 years. It is characterized by seizures, often prolonged, with predominantly autonomic symptoms and mainly ictal vomiting. EEG shows shifting and\\/or multiple foci, often with occipital dominance. Despite characteristic clinical and EEG manifestations Panayiotopoulos

Michael Michael; Katerina Tsatsou; Colin D. Ferrie

2010-01-01

215

Occipital sources of resting-state alpha rhythms are related to local gray matter density in subjects with amnesic mild cognitive impairment and Alzheimer's disease.  

PubMed

Occipital sources of resting-state electroencephalographic (EEG) alpha rhythms are abnormal, at the group level, in patients with amnesic mild cognitive impairment (MCI) and Alzheimer's disease (AD). Here, we evaluated the hypothesis that amplitude of these occipital sources is related to neurodegeneration in occipital lobe as measured by magnetic resonance imaging. Resting-state eyes-closed EEG rhythms were recorded in 45 healthy elderly (Nold), 100 MCI, and 90 AD subjects. Neurodegeneration of occipital lobe was indexed by weighted averages of gray matter density, estimated from structural MRIs. EEG rhythms of interest were alpha 1 (8-10.5 Hz) and alpha 2 (10.5-13 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography. Results showed a positive correlation between occipital gray matter density and amplitude of occipital alpha 1 sources in Nold, MCI, and AD subjects as a whole group (r = 0.3, p = 0.000004, N = 235). Furthermore, there was a positive correlation between the amplitude of occipital alpha 1 sources and cognitive status as revealed by Mini Mental State Examination score across all subjects (r = 0.38, p = 0.000001, N = 235). Finally, amplitude of occipital alpha 1 sources allowed a moderate classification of individual Nold and AD subjects (sensitivity: 87.8%; specificity: 66.7%; area under the receiver operating characteristic curve: 0.81). These results suggest that the amplitude of occipital sources of resting-state alpha rhythms is related to AD neurodegeneration in occipital lobe along pathologic aging. PMID:25442118

Babiloni, Claudio; Del Percio, Claudio; Boccardi, Marina; Lizio, Roberta; Lopez, Susanna; Carducci, Filippo; Marzano, Nicola; Soricelli, Andrea; Ferri, Raffaele; Triggiani, Antonio Ivano; Prestia, Annapaola; Salinari, Serenella; Rasser, Paul E; Basar, Erol; Famà, Francesco; Nobili, Flavio; Yener, Görsev; Emek-Sava?, Derya Durusu; Gesualdo, Loreto; Mundi, Ciro; Thompson, Paul M; Rossini, Paolo M; Frisoni, Giovanni B

2015-02-01

216

Widespread heterogeneous neuronal loss across the cerebral cortex in Huntington's disease.  

PubMed

Huntington's disease is an autosomal dominant neurodegenerative disease characterized by neuronal degeneration in the basal ganglia and cerebral cortex, and a variable symptom profile. Although progressive striatal degeneration is known to occur and is related to symptom profile, little is known about the cellular basis of symptom heterogeneity across the entire cerebral cortex. To investigate this, we have undertaken a double blind study using unbiased stereological cell counting techniques to determine the pattern of cell loss in six representative cortical regions from the frontal, parietal, temporal, and occipital lobes in the brains of 14 Huntington's disease cases and 15 controls. The results clearly demonstrate a widespread loss of total neurons and pyramidal cells across all cortical regions studied, except for the primary visual cortex. Importantly, the results show that cell loss is remarkably variable both within and between Huntington's disease cases. The results also show that neuronal loss in the primary sensory and secondary visual cortices relate to Huntington's disease motor symptom profiles, and neuronal loss across the associational cortices in the frontal, parietal and temporal lobes is related to both Huntington's disease motor and to mood symptom profiles. This finding considerably extends a previous study (Thu et al., Brain, 2010; 133:1094-1110) which showed that neuronal loss in the primary motor cortex was related specifically to the motor symptom profiles while neuronal loss in the anterior cingulate cortex was related specifically to mood symptom profiles. The extent of cortical cell loss in the current study was generally related to the striatal neuropathological grade, but not to CAG repeat length on the HTT gene. Overall our findings show that Huntington's disease is characterized by a heterogeneous pattern of neuronal cell loss across the entire cerebrum which varies with symptom profile. PMID:25062764

Nana, Alissa L; Kim, Eric H; Thu, Doris C V; Oorschot, Dorothy E; Tippett, Lynette J; Hogg, Virginia M; Synek, Beth J; Roxburgh, Richard; Waldvogel, Henry J; Faull, Richard L M

2014-01-01

217

Paediatric epilepsy surgery in the posterior cortex: a study of 62 cases.  

PubMed

Past surgical series have emphasized the diagnostic complexity of posterior cortex epilepsy. Available data are sparse, especially in children, and most published series report a high number of surgical failures and post-operative neurological deficits. In this article, we present a paediatric cohort of 62 children who underwent surgery for drug resistant posterior cortex epilepsy before the age of 16 years with a mean post-operative follow-up of 6.94 years (range: 2-16). Mean age at epilepsy onset was 3.2 years and 28 children (45%) had onset before 1 year of age. The mean age at surgery was 7.9 years (range: 1-16). Daily seizures were present in 63% of children. MRI was positive in 58 cases (93.5%) and invasive stereo-EEG was judged mandatory in 24/62 (39%) of patients. Surgery was confined to the parietal lobe in 11 children, the occipital lobe in 8, the occipito-parietal region in four, the occipito-temporal region in 18, and involved both the temporal and parietal lobes in the remaining 21. Following surgery, 53 subjects (85.5%) remained seizure-free and among those who underwent a SEEG procedure, 75% achieved seizure freedom. Focal cortical dysplasia was the most frequent histopathological diagnosis (50%), followed by tumoural (24%) and gliotic lesions (14.5%). An older age at epilepsy onset, the presence of a rather restricted epileptogenic area, and a complete resection of the epileptogenic zone were predictive of a favourable surgical outcome. These results demonstrate that a good surgical outcome is possible in children with drug resistant posterior cortex epilepsy. Accurate analysis of the chronology of ictal semiology and electrophysiological features, viewed in the context of the complete electroclinical pattern, provides a topographical orientation for posterior cortex epilepsy and, together with the presence of a lesion detectable on imaging, may improve the rate of surgical success of posterior cortex epilepsy at paediatric age. PMID:24853765

Liava, Alexandra; Mai, Roberto; Tassi, Laura; Cossu, Massimo; Sartori, Ivana; Nobili, Lino; Lo Russo, Giorgio; Francione, Stefano

2014-06-01

218

Binding 3D Object Perception in Human Visual Cortex  

PubMed Central

How do visual luminance, shape, motion, and depth bind together in the brain to represent the coherent percept of a 3D object within hundreds of milliseconds (ms)? We provide evidence from simultaneous magneto-encephalographic (MEG) and electro-encephalographic (EEG) data that perception of 3D objects defined by luminance or motion elicits sequential activity in human visual cortices within 500 ms. Following activation of the primary visual cortex around 100 ms, 3D objects elicited sequential activity with only little overlap (dynamic 3D shapes: hMT- LO-vTemp, stationary 3D shapes: LO-vTemp). A delay of 80 ms, both in MEG / EEG responses and in reaction times (RT), was found when additional motion information was processed. We also found significant positive correlations between RT, and MEG and EEG responses in the right temporal location. After about 400 ms, long lasting activity was observed in the parietal cortex and concurrently in previously activated regions. Novel time-frequency analyses indicate that the activity in the Lateral Occipital (LO) complex is associated with an increase of induced power in the gamma band, a hallmark of binding. The close correspondence of an induced gamma response with concurrent sources located in LO in both experimental conditions at different points in time (~200 ms for luminance and ~300 ms for dynamic cues) strongly suggests that LO is the key region for the assembly of object features. The assembly is fed forward to achieve coherent perception of a 3D object within 500 ms. PMID:18052779

Jiang, Yang; Boehler, C. N.; Nönnig, Nina; Düzel, Emrah; Hopf, Jens-Max; Heinze, Hans-Jochen; Schoenfeld, Mircea Ariel

2013-01-01

219

Reading without the left ventral occipito-temporal cortex  

PubMed Central

The left ventral occipito-temporal cortex (LvOT) is thought to be essential for the rapid parallel letter processing that is required for skilled reading. Here we investigate whether rapid written word identification in skilled readers can be supported by neural pathways that do not involve LvOT. Hypotheses were derived from a stroke patient who acquired dyslexia following extensive LvOT damage. The patient followed a reading trajectory typical of that associated with pure alexia, re-gaining the ability to read aloud many words with declining performance as the length of words increased. Using functional MRI and dynamic causal modelling (DCM), we found that, when short (three to five letter) familiar words were read successfully, visual inputs to the patient’s occipital cortex were connected to left motor and premotor regions via activity in a central part of the left superior temporal sulcus (STS). The patient analysis therefore implied a left hemisphere “reading-without-LvOT” pathway that involved STS. We then investigated whether the same reading-without-LvOT pathway could be identified in 29 skilled readers and whether there was inter-subject variability in the degree to which skilled reading engaged LvOT. We found that functional connectivity in the reading-without-LvOT pathway was strongest in individuals who had the weakest functional connectivity in the LvOT pathway. This observation validates the findings of our patient’s case study. Our findings highlight the contribution of a left hemisphere reading pathway that is activated during the rapid identification of short familiar written words, particularly when LvOT is not involved. Preservation and use of this pathway may explain how patients are still able to read short words accurately when LvOT has been damaged. PMID:23017598

Seghier, Mohamed L.; Neufeld, Nicholas H.; Zeidman, Peter; Leff, Alex P.; Mechelli, Andrea; Nagendran, Arjuna; Riddoch, Jane M.; Humphreys, Glyn W.; Price, Cathy J.

2012-01-01

220

Transcallosal inhibition dampens neural responses to high contrast stimuli in human visual cortex.  

PubMed

Visual cortical areas in the two hemispheres interact via the corpus callosum, but the precise role of the callosal pathway in visual processing remains controversial. Here we have investigated the function of transcallosal projections in human primary visual cortex (V1). Visual evoked potentials (VEPs) triggered by grating stimuli of different contrasts were recorded before and after functional inactivation of the occipital cortex of one hemisphere via off-line low-frequency repetitive transcranial magnetic stimulation (rTMS; 0.5 Hz stimulation for 20 min). VEPs were recorded in V1 before (T0), immediately after (T1) and 45' following the completion of rTMS (T2). We found that low-frequency rTMS had an inhibitory effect on VEPs amplitudes at all contrasts in the treated side. Remarkably, reduction of VEP amplitudes in the inhibited hemisphere at T1 was accompanied by an increase in VEP amplitudes in the contralateral side only at mid-high contrasts (50-90%). This disinhibitory effect was observed with both central and hemifield stimulation. No changes in VEP amplitudes were observed when rTMS was applied to a cortical site more anterior with respect to V1. These data provide the first evidence that a mechanism of transcallosal inhibition dampens neural responses at high contrasts in human visual cortex. PMID:21557988

Bocci, T; Caleo, M; Giorli, E; Barloscio, D; Maffei, L; Rossi, S; Sartucci, F

2011-07-28

221

Decoding face categories in diagnostic subregions of primary visual cortex  

PubMed Central

Higher visual areas in the occipitotemporal cortex contain discrete regions for face processing, but it remains unclear if V1 is modulated by top-down influences during face discrimination, and if this is widespread throughout V1 or localized to retinotopic regions processing task-relevant facial features. Employing functional magnetic resonance imaging (fMRI), we mapped the cortical representation of two feature locations that modulate higher visual areas during categorical judgements – the eyes and mouth. Subjects were presented with happy and fearful faces, and we measured the fMRI signal of V1 regions processing the eyes and mouth whilst subjects engaged in gender and expression categorization tasks. In a univariate analysis, we used a region-of-interest-based general linear model approach to reveal changes in activation within these regions as a function of task. We then trained a linear pattern classifier to classify facial expression or gender on the basis of V1 data from ‘eye’ and ‘mouth’ regions, and from the remaining non-diagnostic V1 region. Using multivariate techniques, we show that V1 activity discriminates face categories both in local ‘diagnostic’ and widespread ‘non-diagnostic’ cortical subregions. This indicates that V1 might receive the processed outcome of complex facial feature analysis from other cortical (i.e. fusiform face area, occipital face area) or subcortical areas (amygdala). PMID:23373719

Petro, Lucy S; Smith, Fraser W; Schyns, Philippe G; Muckli, Lars

2013-01-01

222

The intention to conceal activates the right prefrontal cortex: an event-related potential study.  

PubMed

Recent studies on deception have shown that a late positive potential (LPP), a component of event-related brain potentials, is elicited when a participant wishes to conceal recognition of the eliciting stimulus. The LPP occurs about 500?ms after stimulus onset and has an occipital scalp distribution with concurrent negativity at frontal sites. The present study investigated the cortical sources of the LPP associated with the intention to conceal. Standardized low-resolution electromagnetic tomography analysis was applied on previously published concealment-related LPP data (Matsuda, Nittono, and Ogawa, 2013, N=30). The cortical sources of the LPP were estimated in the right middle frontal gyrus and the right inferior frontal gyrus, which fits well with the findings of fMRI studies. Previous research suggests that activities in the middle frontal gyrus and the right inferior frontal gyrus are associated with cognitive control and that greater relative right than left frontal activities are associated with withdrawal motivation. On the basis of these findings, it is concluded that the LPP may reflect cognitive control with withdrawal motivation that is recruited by the participants' goal of concealing their recognition and avoiding disclosure. A positive potential at occipital sites can be a sign of the activation in the prefrontal cortex. PMID:25646583

Matsuda, Izumi; Nittono, Hiroshi

2015-03-01

223

Auditory Cortex: Representation through Sparsification?  

PubMed Central

Summary The recent discovery of combination-sensitive neurons in the primary auditory cortex of awake marmosets may reconcile previous, apparently contradictory, findings that cortical neurons produce strong, sustained responses, but also represent stimuli sparsely. PMID:20064424

Willmore, Ben D.B.; King, Andrew J.

2015-01-01

224

Cerebral cortex modulation of pain  

Microsoft Academic Search

Pain is a complex experience encompassing sensory-discriminative, affective-motivational and cognitiv e-emotional components mediated by different mechanisms. Contrary to the traditional view that the cerebral cortex is not involved in pain perception, an extensive cortical network associated with pain processing has been revealed using multiple methods over the past decades. This network consistently includes, at least, the anterior cingulate cortex, the

Yu-feng Xie; Fu-quan Huo; Jing-shi Tang

2009-01-01

225

MRI volumetry of prefrontal cortex  

NASA Astrophysics Data System (ADS)

Prefrontal cortex volumetry by brain magnetic resonance (MR) is required to estimate changes postulated to occur in certain psychiatric and neurologic disorders. A semiautomated method with quantitative characterization of its performance is sought to reliably distinguish small prefrontal cortex volume changes within individuals and between groups. Stereological methods were tested by a blinded comparison of measurements applied to 3D MR scans obtained using an MPRAGE protocol. Fixed grid stereologic methods were used to estimate prefrontal cortex volumes on a graphic workstation, after the images are scaled from 16 to 8 bits using a histogram method. In addition images were resliced into coronal sections perpendicular to the bicommissural plane. Prefrontal cortex volumes were defined as all sections of the frontal lobe anterior to the anterior commissure. Ventricular volumes were excluded. Stereological measurement yielded high repeatability and precision, and was time efficient for the raters. The coefficient of error was cortex boundaries on 3D images was critical to obtaining accurate measurements. MR prefrontal cortex volumetry by stereology can yield accurate and repeatable measurements. Small frontal lobe volume reductions in patients with brain disorders such as depression and schizophrenia can be efficiently assessed using this method.

Sheline, Yvette I.; Black, Kevin J.; Lin, Daniel Y.; Pimmel, Joseph; Wang, Po; Haller, John W.; Csernansky, John G.; Gado, Mokhtar; Walkup, Ronald K.; Brunsden, Barry S.; Vannier, Michael W.

1995-05-01

226

Cue-Invariant Networks for Figure and Background Processing in Human Visual Cortex  

PubMed Central

Lateral occipital cortical areas are involved in the perception of objects, but it is not clear how these areas interact with first tier visual areas. Using synthetic images portraying a simple texture-defined figure and an electrophysiological paradigm that allows us to monitor cortical responses to figure and background regions separately, we found distinct neuronal networks responsible for the processing of each region. The figure region of our displays was tagged with one temporal frequency (3.0 Hz) and the background region with another (3.6 Hz). Spectral analysis was used to separate the responses to the two regions during their simultaneous presentation. Distributed source reconstructions were made by using the minimum norm method, and cortical current density was measured in a set of visual areas defined on retinotopic and functional criteria with the use of functional magnetic resonance imaging. The results of the main experiments, combined with a set of control experiments, indicate that the figure region, but not the background, was routed preferentially to lateral cortex. A separate network extending from first tier through more dorsal areas responded preferentially to the background region. The figure-related responses were mostly invariant with respect to the texture types used to define the figure, did not depend on its spatial location or size, and mostly were unaffected by attentional instructions. Because of the emergent nature of a segmented figure in our displays, feedback from higher cortical areas is a likely candidate for the selection mechanism by which the figure region is routed to lateral occipital cortex. PMID:17093091

Appelbaum, L. Gregory; Wade, Alex R.; Vildavski, Vladimir Y.; Pettet, Mark W.; Norcia, Anthony M.

2009-01-01

227

Retinotopic and lateralized processing of spatial frequencies in human visual cortex during scene categorization.  

PubMed

Using large natural scenes filtered in spatial frequencies, we aimed to demonstrate that spatial frequency processing could not only be retinotopically mapped but could also be lateralized in both hemispheres. For this purpose, participants performed a categorization task using large black and white photographs of natural scenes (indoors vs. outdoors, with a visual angle of 24° × 18°) filtered in low spatial frequencies (LSF), high spatial frequencies (HSF), and nonfiltered scenes, in block-designed fMRI recording sessions. At the group level, the comparison between the spatial frequency content of scenes revealed first that, compared with HSF, LSF scene categorization elicited activation in the anterior half of the calcarine fissures linked to the peripheral visual field, whereas, compared with LSF, HSF scene categorization elicited activation in the posterior part of the occipital lobes, which are linked to the fovea, according to the retinotopic property of visual areas. At the individual level, functional activations projected on retinotopic maps revealed that LSF processing was mapped in the anterior part of V1, whereas HSF processing was mapped in the posterior and ventral part of V2, V3, and V4. Moreover, at the group level, direct interhemispheric comparisons performed on the same fMRI data highlighted a right-sided occipito-temporal predominance for LSF processing and a left-sided temporal cortex predominance for HSF processing, in accordance with hemispheric specialization theories. By using suitable method of analysis on the same data, our results enabled us to demonstrate for the first time that spatial frequencies processing is mapped retinotopically and lateralized in human occipital cortex. PMID:23574583

Musel, Benoit; Bordier, Cécile; Dojat, Michel; Pichat, Cédric; Chokron, Sylvie; Le Bas, Jean-François; Peyrin, Carole

2013-08-01

228

Increased glutamate levels observed upon functional activation in the anterior cingulate cortex using the Stroop Task and functional spectroscopy  

PubMed Central

It has been shown in recent studies that it is possible to detect changes in the main excitatory neurotransmitter, glutamate, upon functional activation with visual and motor paradigms using a 7?T MRI and functional magnetic resonance spectroscopy. A cognitive task would be desirable for this technique because it could then be used to examine psychiatric disorders that have cognitive deficiencies. The aim of the work presented here was to use functional magnetic resonance spectroscopy with a 7?T MRI to show that increases in glutamate can be observed within the anterior cingulate cortex using the Stroop Task as the activation paradigm in healthy controls. Significant glutamate increases (0.24±0.09?µmol/g, P<0.025), comparable with what has been reported in the studies of the occipital cortex and motor cortex, were observed when the participants (n=7) performed the task, followed by a trend toward returning to baseline in the post-task recovery period (?0.23±0.13?µmol/g). This method would be ideal for the study of neuropsychiatric disorders that have been shown to have abnormal resting glutamate levels and cognitive deficiencies in the anterior cingulate cortex, such as schizophrenia. This exploratory study is the first to demonstrate functional magnetic resonance spectroscopy in the anterior cingulate with a cognitive task using a 7?T MRI. PMID:25536234

Schaefer, Betsy; Densmore, Maria; Neufeld, Richard W.J.; Rajakumar, Nagalingam; Williamson, Peter C.; Théberge, Jean

2015-01-01

229

Quantitative assessment of diffuse optical tomography sensitivity to the cerebral cortex using a whole-head probe  

NASA Astrophysics Data System (ADS)

We quantify the variability in diffuse optical tomography (DOT) sensitivity over the cortical surface in eight young adult subjects. We use the 10/5 electroencephalography system as a basis for our whole-head optical high-density probe design. The contrast-to-noise ratio (CNR) is calculated along with the percentage of the cortex that is above a CNR = 0 dB threshold. We also quantify the effect of including vasculature on the forward model and list our assumptions that allow us to estimate light penetration depth in the head. We show that using the 10/5 system for the optical probe design allows for the measurement of 37% of the cortical surface on average, with a mean CNR in the visible region of 5.5 dB. Certain anatomical regions, such as the lateral occipital cortex, had a very high percentage above the CNR threshold, while other regions such as the cingulate cortex were not measurable. Vasculature blocked optical sensitivity over 1% of the cortex. Cortical coverage was positively correlated with intracranial volume and relative cerebrospinal fluid volume, and negatively correlated with relative scalp volume and skull volume. These contributions allow experimenters to understand how anatomical variation in a subject population may impact DOT or functional near-infrared spectroscopy measurements.

Perdue, Katherine L.; Fang, Qianqian; Diamond, Solomon G.

2012-05-01

230

Quantitative assessment of diffuse optical tomography sensitivity to the cerebral cortex using a whole-head probe.  

PubMed

We quantify the variability in diffuse optical tomography (DOT) sensitivity over the cortical surface in eight young adult subjects. We use the 10/5 electroencephalography system as a basis for our whole-head optical high-density probe design. The contrast-to-noise ratio (CNR) is calculated along with the percentage of the cortex that is above a CNR = 0 dB threshold. We also quantify the effect of including vasculature on the forward model and list our assumptions that allow us to estimate light penetration depth in the head. We show that using the 10/5 system for the optical probe design allows for the measurement of 37% of the cortical surface on average, with a mean CNR in the visible region of 5.5 dB. Certain anatomical regions, such as the lateral occipital cortex, had a very high percentage above the CNR threshold, while other regions such as the cingulate cortex were not measurable. Vasculature blocked optical sensitivity over 1% of the cortex. Cortical coverage was positively correlated with intracranial volume and relative cerebrospinal fluid volume, and negatively correlated with relative scalp volume and skull volume. These contributions allow experimenters to understand how anatomical variation in a subject population may impact DOT or functional near-infrared spectroscopy measurements. PMID:22513789

Perdue, Katherine L; Fang, Qianqian; Diamond, Solomon G

2012-05-21

231

Parietal and occipital lobe contributions to perception of straight ahead orientation  

PubMed Central

OBJECTIVES—Several studies have investigated how peripheral stimulation affects the perception of body orientation in healthy subjects. The studies showed that opposing stimulation of two different input modalities can cancel out, leaving perception of body orientation unchanged. It was ascertained whether a comparable phenomenon could be found in brain damaged patients with two distinct disorders which individually lead to opposing shifts of the perceived midline.?METHODS—The visual subjective straight ahead was measured in patients with pure neglect, pure hemianopia, or a combination of neglect and hemianopia.?RESULTS—As in previous studies, patients with pure neglect displayed an ipsilesional displacement of the perceived straight ahead. Patients with pure hemianopia showed a contralesional shift. By contrast, no significant midline shift occurred in the patients with both neglect and hemianopia.?CONCLUSIONS—Neglect and hemianopia interact so that opposing biases in the perception of body orientation neutralise each other. Both parietal and occipital areas seem to contribute to the perception of straight ahead body orientation and seem to have counteracting effects when lesioned in the same hemisphere.?? PMID:10519859

Ferber, S.; Karnath, H.

1999-01-01

232

Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM Sleep  

PubMed Central

Over the past several years meditation practice has gained increasing attention as a non-pharmacological intervention to provide health related benefits, from promoting general wellness to alleviating the symptoms of a variety of medical conditions. However, the effects of meditation training on brain activity still need to be fully characterized. Sleep provides a unique approach to explore the meditation-related plastic changes in brain function. In this study we performed sleep high-density electroencephalographic (hdEEG) recordings in long-term meditators (LTM) of Buddhist meditation practices (approximately 8700 mean hours of life practice) and meditation naive individuals. We found that LTM had increased parietal-occipital EEG gamma power during NREM sleep. This increase was specific for the gamma range (25–40 Hz), was not related to the level of spontaneous arousal during NREM and was positively correlated with the length of lifetime daily meditation practice. Altogether, these findings indicate that meditation practice produces measurable changes in spontaneous brain activity, and suggest that EEG gamma activity during sleep represents a sensitive measure of the long-lasting, plastic effects of meditative training on brain function. PMID:24015304

Ferrarelli, Fabio; Smith, Richard; Dentico, Daniela; Riedner, Brady A.; Zennig, Corinna; Benca, Ruth M.; Lutz, Antoine; Davidson, Richard J.; Tononi, Giulio

2013-01-01

233

Occipital Artery Function during the Development of 2-Kidney, 1-Clip Hypertension in Rats  

PubMed Central

This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs. On day 9, 2K-1C rats had higher mean arterial blood pressures, heart rates, and plasma renin concentrations than SHAM rats. The contractile responses to AII were markedly diminished in both proximal and distal segments of OAs from 2K-1C rats as compared to those from SHAM rats. The responses elicited by AVP were substantially greater in distal than in proximal segments of OAs from SHAM rats and that AVP elicited similar responses in OA segments from 2K-1C rats. The responses elicited by 5-HT were similar in proximal and distal segments from SHAM and 2K-1C rats. These results demonstrate that continued exposure to circulating AII and AVP in 2K-1C rats reduces the contractile efficacy of AII but not AVP or 5-HT. The diminished responsiveness to AII may alter the physiological status of OAs in vivo. PMID:25140254

Chelko, Stephen P.; Schmiedt, Chad W.; Lewis, Tristan H.; Robertson, Tom P.; Lewis, Stephen J.

2014-01-01

234

Vasopressin-induced constriction of the isolated rat occipital artery is segment-dependent  

PubMed Central

Background Circulating factors delivered to the nodose ganglion (NG) by the occipital artery (OA) have shown to affect vagal afferent activity, and thus the contractile state of the OA may influence blood flow to the NG. Methods OA were isolated and bisected into proximal and distal segments, relative to the external carotid artery. Results Bisection, highlighted stark differences between maximal contractile responses and OA sensitivity. Specifically, maximum responses to vasopressin and the V1 receptor agonist, were significantly higher in distal than proximal segments. Distal segments were significantly more sensitive to 5-HT and the 5-HT2 receptor agonist than proximal segments. AT2, V2 and 5-HT1B/1D receptor agonists did not elicit vascular responses. Additionally, AT1 receptor agonists elicited mild, yet not significantly different maximal responses between segments. Conclusion The results of this study are consistent with contractile properties of rat OA being mediated via AT1, V1 and 5-HT2 receptors, and are dependent upon the OA segment. Furthermore, vasopressin-induced constriction of the OA, regardless of a bolus dose or a first and second concentration response curve retained this unique segmental difference and therefore we hypothesize this may be a pathophysiological response in the regulation of blood flow through the OA. PMID:24192548

Chelko, Stephen P.; Schmiedt, Chad W.; Lewis, Tristan H.; Lewis, Stephen J.; Robertson, Tom P.

2014-01-01

235

Delayed recurrent arachnoid cyst of the occipital convexity in an elderly woman.  

PubMed

A 62-year-old woman presented with a symptomatic arachnoid cyst of the right occipital convexity manifesting as visual disturbances and headache. She underwent craniotomy with membranectomy and fenestration to the subarachnoid space. Postoperatively, her complaints disappeared and brain magnetic resonance (MR) imaging showed cyst shrinkage. During the first 1 year after surgery, she made a good recovery without clinical symptoms or cyst enlargement. However, she complained of visual disturbances after 6 years. Brain MR imaging revealed cyst enlargement and Goldmann perimetry detected left lower quadrantanopia. The diagnosis was recurrent arachnoid cyst. A second surgical procedure was performed including membranectomy for histological examination of the cyst membrane, and an Ommaya reservoir was inserted into the cyst cavity to prevent further cyst enlargement. The histological findings were compatible with arachnoid cyst, similar to the results seen at the first surgery. She was discharged 3 weeks after the second operation with no complications, and follow up continues as an outpatient. Patients with symptomatic arachnoid cysts typically have good progress after surgery, but the present case shows that follow up should continue for at least 6 years after surgery, even if cyst volume reduction was initially favorable. PMID:19318741

Suzuki, Masanori; Tamaki, Tomonori; Toda, Shigeki; Tsuchiya, Masato; Kogure, Kazunari; Hosone, Masaru; Node, Yoji; Teramoto, Akira

2009-03-01

236

Ultrasound-guided atlanto-occipital puncture for cerebrospinal fluid analysis on the standing horse.  

PubMed

The atlanto-occipital site (AO) is convenient for retrieving an adequate volume and quality of cerebrospinal fluid (CSF) in the diagnosis of neurological disease in horses. However, general anaesthesia is not always possible for horses displaying severe neurological signs, or for economical reasons. The objectives of the present work were to determine the feasibility and safety of ultrasound-guided CSF puncture at the AO site on the standing horse. Seven horses (six healthy and one mildly ataxic) were sedated with acepromazine (0.02 mg/kg bodyweight intravenously or 0.04 mg/kg bodyweight intramuscularly) and detomidine (0.01 mg/kg bodyweight intravenously), and placed in stocks or in a recovery stall with the head kept on a headstand. Puncture was performed by ultrasonographic guidance with a parasagittal technique, as previously described, using a 20 g, 3.5 inch spinal needle. In all horses, no adverse reaction was observed when crossing the dura mater and 20 ml of CSF was rapidly retrieved without any blood contamination. Ultrasound-guided CSF puncture can be performed easily at the AO site on a healthy standing horse. Regarding the potential risk of this procedure, safety measures and close observation are essential. Further studies on a larger amount of ataxic horses are also required before considering this technique as an alternative option for CSF puncture. PMID:24225443

Depecker, M; Bizon-Mercier, C; Couroucé-Malblanc, A

2014-01-11

237

MRI of the tectorial and posterior atlanto-occipital membranes in the late stage of whiplash injury  

Microsoft Academic Search

Our aim was to characterise and classify permanent structural changes in the tectorial and posterior atlanto-occipital membranes several years after a whiplash injury, and to evaluate the reliability of our classification. We obtained sagittal proton density-weighted images of the craniovertebral junction of 92 whiplash-injured and 30 uninjured individuals. Structural abnormalities in the two membranes were classified as grades 1–3 independently by three radiologists

J. Krakenes; B. R. Kaale; G. Moen; H. Nordli; N. E. Gilhus; J. Rorvik

2003-01-01

238

Duraplasty with freeze-dried cadaveric dura versus occipital pericranium for Chiari type I malformation: Comparative study  

Microsoft Academic Search

Summary  During the period from October 1, 1989 to October 1, 1995 a total of 26 cases of Chiari type I malformation not associated\\u000a with syringomyelia were attended in our Hospital. All patients underwent cranio-cervical decompression, with occipital craniectomy\\u000a and removal of the posterior arch of C1. In 3\\/26 (11.5%) cases an additional C2 laminectomy had to be performed and in

V. Vanaclocha; N. Saiz-Sapena

1997-01-01

239

Supplement to "Top-down flow of visual spatial attention signals from parietal to occipital cortex", Journal of Vision 9(13):18:1-14  

E-print Network

, and Michael A. Silver Supplementary Figure 1. Relationship between the delay calculated as mean of the phase versus frequency plots. All pairs of areas exhibiting significant differences (attention and binned into four groups (magenta, green, cyan, black curves) based on delay period duration. Responses

Whitney, David

240

Probabilistic and single-subject retinotopic maps reveal the topographic organization of face patches in the macaque cortex.  

PubMed

Face perception is crucial to survival among social primates. It has been suggested that a group of extrastriate cortical regions responding more strongly to faces than to nonface objects is critical for face processing in primates. It is generally assumed that these regions are not retinotopically organized, as with human face-processing areas, showing foveal bias but lacking any organization with respect to polar angle. Despite many electrophysiological studies targeting monkey face patches, the retinotopic organization of these patches remains largely unclear. We have examined the relationship between cortical face patches and the topographic organization of extrastriate cortex using biologically relevant, phase-encoded retinotopic mapping stimuli in macaques. Single-subject fMRI results indicated a gradual shift from highly retinotopic to no topographic organization from posterior to anterior face patches in inferotemporal cortex. We also constructed a probabilistic retinotopic atlas of occipital and ventral extrastriate visual cortex. By comparing this probabilistic map to the locations of face patches at the group level, we showed that a previously identified posterior lateral temporal face patch (PL) is located within the posterior inferotemporal dorsal (PITd) retinotopic area. Furthermore, we identified a novel face patch posterior PL, which is located in retinotopically organized transitional area V4 (V4t). Previously published coordinates of human PITd coincide with the group-level occipital face area (OFA), according to a probabilistic map derived from a large population, implying a potential correspondence between monkey PL/PITd and human OFA/PITd. Furthermore, the monkey middle lateral temporal face patch (ML) shows consistent foveal biases but no obvious polar-angle structure. In contrast, middle fundus temporal (MF), anterior temporal and prefrontal monkey face patches lacked topographic organization. PMID:25080579

Janssens, Thomas; Zhu, Qi; Popivanov, Ivo D; Vanduffel, Wim

2014-07-30

241

A rare case of atlantooccipital dissociation in the context of occipitalization of the atlas, with a 2-year follow-up: case report.  

PubMed

Atlantooccipital dislocation (AOD) is a rare and often fatal injury. In cases of survival, residual deficits are severe and often include cranial nerve palsy, quadriplegia, or respiratory issues. Occipitalization is defined as partial or complete congenital fusion of the occiput to the atlas and is exceptionally rare. The authors present a rare case of AOD superimposed on a congenital occipitalization of the atlas. This 39-year-old man had AOD following a motor vehicle collision. On examination, his overall motor score on the American Spinal Injury Association scale was 5/100, and his rectal tone was absent. Computed tomography demonstrated AOD in an area of occipitalization. Magnetic resonance imaging revealed ligamentous injury leading to C1-2 instability. Intervention included occipital cervical instrumentation fusion from the occiput to C-3. Six months postoperatively, imaging revealed fusion of the graft and consolidation of the fractured occipitalization. At the 2-year follow-up, the patient's strength was 3/5 for wrist extension and handgrip on the right side and full strength in the rest of the myotomes. Bladder and bowel function was also normalized. A high-velocity collision led to disruption of the atlantooccipital ligaments and fracture of the occipitalized lateral masses in this patient. Internal fixation and fusion led to good fusion postoperatively. Occipitalization probably led to abnormal joint mechanics at the C1-occiput junction, which might have altered the amount of force required to fracture the occipitalization and produce AOD. This difference may partially account for the favorable neurological outcome in the featured patient compared with traditional cases of AOD. PMID:23198835

Chaudhary, Navjot; Wang, Bill H; Gurr, Kevin R; Bailey, Stewart I; Bailey, Christopher S

2013-02-01

242

Occipital Nerve Stimulation for Chronic Migraine—A Systematic Review and Meta-Analysis  

PubMed Central

Background Chronic migraine is a debilitating headache disorder that has significant impact on quality of life. Stimulation of peripheral nerves is increasingly being used to treat chronic refractory pain including headache disorders. This systematic review examines the effectiveness and adverse effects of occipital nerve stimulation (ONS) for chronic migraine. Methods Databases, including the Cochrane Library, MEDLINE, EMBASE, CINAHL and clinical trial registers were searched to September 2014. Randomized controlled trials (RCTs), other controlled and uncontrolled observational studies and case series (n? 10) were eligible. RCTs were assessed using the Cochrane risk of bias tool. Meta-analysis was carried out using a random-effects model. Findings are presented in summary tables and forest plots. Results Five RCTs (total n=402) and seven case series (total n=115) met the inclusion criteria. Pooled results from three multicenter RCTs show that ONS was associated with a mean reduction of 2.59 days (95% CI 0.91 to 4.27, I2=0%) of prolonged, moderate to severe headache per month at 3 months compared with a sham control. Results for other outcomes generally favour ONS over sham controls but quantitative analysis was hampered by incomplete publication and reporting of trial data. Lead migration and infections are common and often require revision surgery. Open-label follow-up of RCTs and case series suggest long-term effectiveness can be maintained in some patients but evidence is limited. Conclusions While the effectiveness of ONS compared to sham control has been shown in multiple RCTs, the average effect size is modest and may be exaggerated by bias as achieving effective blinding remains a methodological challenge. Further measures to reduce the risk of adverse events and revision surgery are needed. Systematic Review Registration this systematic review is an update and expanded work of part of a broader review registered with PROSPERO. Registration No. CRD42012002633. PMID:25793740

Chen, Yen-Fu; Bramley, George; Unwin, Gemma; Hanu-Cernat, Dalvina; Dretzke, Janine; Moore, David; Bayliss, Sue; Cummins, Carole; Lilford, Richard

2015-01-01

243

Fractures of the occipital condyle clinical spectrum and course in eight patients  

PubMed Central

Introduction: Occipital condyle fractures (OCFs) are considered to be rare injuries. OCFs are now diagnosed more often because of the widespread use of computed tomography. Our aim is to report the incidence, treatment and long term outcome of 8 patients with OCFs. Materials and Methods: All patients presenting with multiple trauma from 1993 to 2006 were analyzed retrospectively. Characteristics and course of the treatment were evaluated. Follow-up was performed after 11,7 years (range 5,9 to 19,3 years). Results: Nine cases of OCF in 8 patients were identified. All injuries resulted from high velocity trauma. The average scores on the ISS Scale were 39,6 (24-75) and 7,3 (3-15) on the GCS. According to Anderson's classification, 5 cases of Type III and 4 cases of Type I fractures were identified. According to Tuli's classification, 5 cases of Type IIA and 4 cases of Type I were found. Indications for immobilization with the halo-vest were type III injuries according to Anderson's classification or Tuli's type IIA injuries, respectively. Patients with Tuli's type I injuries were treated with a Philadelphia collar for 6 weeks. In one patient with initial complete tetraplegia and one with incomplete neurological deficits the final follow-up neurologic examination showed no neurological impairment at all (Frankel-grade A to E, respectively B to E). At follow-up, 3 patients were asymptomatic. Four patients suffered from mild pain when turning their head, pain medication was necessary in one case only. Discussion: OCF's are virtually undetectable using conventional radiography. In cases of high velocity, cranio-cervical trauma or impaired consciousness, high resolution CT-scans of the craniocervical junction must be performed. We suggest immobilization using a halo device for type III injuries according to Anderson's classification or Tuli's type IIa injuries, respectively. Patients with Tuli's type I injuries should be treated with a Philadelphia collar. PMID:24744561

Krüger, Antonio; Oberkircher, Ludwig; Frangen, Thomas; Ruchholtz, Steffen; Kühne, Christian; Junge, Andreas

2013-01-01

244

Associated injuries and mechanism of atlanto-occipital dislocation caused by trauma.  

PubMed

Injuries associated with traumatic atlanto-occipital dislocation (AOD) leading to death were analyzed in 11 patients, nine injured by traffic accidents, of which five were victims of car-pedestrian accidents. On admission, unconsciousness and respiratory arrest were noted in all patients, and cardiac arrest in nine. Skull and cervical roentgenograms revealed enlargement of the retropharyngeal space due to injury of the vertebral artery or its branches in nine patients, atlanto-axial dislocation (C-1-C-2 separation) in four, and skull fracture in four. Computed tomography demonstrated subarachnoid hemorrhage (SAH) in the upper cervical and posterior fossa in nine patients, fourth ventricular hematoma in seven, and atlas fracture in three. SAH and ventricular hematoma were due to craniocervical injury. Other common injuries were injury of face and head excluding the mandibular region in 10 patients, mandibular fracture in three, severe chest injuries in eight, and intraperitoneal bleeding in two. The overall outcome was poor. Nine patients died within 13 hours of admission, one was diagnosed as brain dead 8 days after the accident, and the other one survived in a persistent vegetative state. Early death is probably caused by associated severe injuries, i.e. chest injuries and intraperitoneal bleeding rather than AOD. Although injury of the mandibular region is known to be associated with AOD, head, breast, and abdominal trauma may also lead to neck hyperextension-flexion in various directions. Whatever the direct cause, a distractive force to the craniocervical joint by hyperextension-flexion appears to be important in the mechanism of AOD. PMID:7566383

Imaizumi, T; Sohma, T; Hotta, H; Teto, I; Imaizumi, H; Kaneko, M

1995-06-01

245

Ontogeny of the spheno-occipital synchondrosis in a modern Queensland, Australian population using computed tomography.  

PubMed

Due to disparity regarding the age at which skeletal maturation of the spheno-occipital synchondrosis occurs in forensic and biological literature, this study provides recalibrated multislice computed tomography (MSCT) age standards for the Australian (Queensland) population, using a Bayesian statistical approach. The sample comprises retrospective cranial/cervical MSCT scans obtained from 448 males and 416 females aged birth to 20 years from the Skeletal Biology and Forensic Anthropology Research Osteological Database. Fusion status of the synchondrosis was scored using a modified six-stage scoring tier on an MSCT platform, with negligible observer error (??=?0.911?±?0.04, intraclass correlation coefficient?=?0.994). Bayesian transition analysis indicates that females are most likely to transition to complete fusion at 13.1 years and males at 15.6 years. Posterior densities were derived for each morphological stage, with complete fusion of the synchondrosis attained in all Queensland males over 16.3 years of age and females aged 13.8 years and older. The results demonstrate significant sexual dimorphism in synchondrosis fusion and are suggestive of intrapopulation variation between major geographic regions in Australia. This study contributes to the growing repository of contemporary anthropological standards calibrated for the Queensland milieu to improve the efficacy of the coronial process for medicolegal death investigation. As a stand-alone age indicator, the basicranial synchondrosis may be consulted as an exclusion criterion when determining the age of majority that constitutes 17 years in Queensland forensic practice. Am J Phys Anthropol 157:42-57, 2015. © 2014 Wiley Periodicals, Inc. PMID:25546173

Lottering, Nicolene; MacGregor, Donna M; Alston, Clair L; Gregory, Laura S

2015-05-01

246

The Functions of the Orbitofrontal Cortex  

ERIC Educational Resources Information Center

The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight…

Rolls, Edmund T.

2004-01-01

247

The insular cortex: a review.  

PubMed

The human insular cortex forms a distinct, but entirely hidden lobe, situated in the depth of the Sylvian fissure. Here, we first review the recent literature on the connectivity and the functions of this structure. It appears that this small lobe, taking up less than 2% of the total cortical surface area, receives afferents from some sensory thalamic nuclei, is (mostly reciprocally) connected with the amygdala and with many limbic and association cortical areas, and is implicated in an astonishingly large number of widely different functions, ranging from pain perception and speech production to the processing of social emotions. Next, we embark on a long, adventurous journey through the voluminous literature on the structural organization of the insular cortex. This journey yielded the following take-home messages: (1) The meticulous, but mostly neglected publications of Rose (1928) and Brockhaus (1940) are still invaluable for our understanding of the architecture of the mammalian insular cortex. (2) The relation of the insular cortex to the adjacent claustrum is neither ontogenetical nor functional, but purely topographical. (3) The insular cortex has passed through a spectacular progressive differentiation during hominoid evolution, but the assumption of Craig (2009) that the human anterior insula has no homologue in the rhesus monkey is untenable. (4) The concept of Mesulam and Mufson (1985), that the primate insula is essentially composed of three concentrically arranged zones, agranular, dysgranular, and granular, is presumably correct, but there is at present much confusion concerning the more detailed architecture of the anterior insular cortex. (5) The large spindle-shaped cells in the fifth layer of the insular cortex, currently known as von Economo neurons (VENs), are not only confined to large-brained mammals, such as whales, elephants, apes, and humans, but also occur in monkeys and prosimians, as well as in the pygmy hippopotamus, the Atlantic walrus, and Florida manatee. Finally, we point out that the human insula presents a unique opportunity for performing an in-depth comparative analysis of the relations between structure and function in a typical sensory and a typical cognitive cortical domain. PMID:22230626

Nieuwenhuys, Rudolf

2012-01-01

248

Impaired synaptic plasticity in the visual cortex of mice lacking ?7-nicotinic receptor subunit.  

PubMed

The primary visual cortex (V1) is the first step in visual information processing and its function may be modulated by acetylcholine through nicotinic receptors (nAChRs). Since our previous work demonstrated that visual acuity and cortical spatial resolution limit were significantly reduced in ?7 knock-out (KO) mice in the absence of retinal alterations, we decided to characterize the contribution of homomeric ?7 nicotinic receptors (?7nAChRs) to visual information processing at the cortical level. We evaluated long-term forms of synaptic plasticity in occipital slices containing V1 from ?7 KO mice and in wild-type (WT) slices perfused with nAChRs selective blocking agents. In ?7 KO mice slices, electrophysiological recordings demonstrated the absence of long-term potentiation (LTP) and long-term depression (LTD) in layer II/III after the stimulation of different intracortical pathways (layer IV or II/III). Furthermore, the acute and selective blockade of ?7nAChRs in slices from WT mice with either ?-bungarotoxin or methyllycaconitine did not alter the expression of LTP and LTD. Conversely, the perfusion with the unspecific nAChRs antagonist mecamylamine impaired LTP and LTD. Our results suggest the presence of impaired synaptic plasticity in the V1 of ?7 KO mice and indicate a different contribution of nAChRs to visual cortex function. PMID:25797465

Criscuolo, C; Accorroni, A; Domenici, L; Origlia, N

2015-05-21

249

Specific EEG Sleep Pattern in the Prefrontal Cortex in Primary Insomnia  

PubMed Central

Objective To assess the specific prefrontal activity in comparison to those in the other main cortical areas in primary insomnia patients and in good sleepers. Methods Fourteen primary insomnia patients and 11 good sleepers were included in the analysis. Participants completed one night of polysomnography in the sleep lab. Power spectra were calculated during the NREM (Non-rapid eyes movements) and the REM (Rapid eyes movements) sleep periods at prefrontal, occipital, temporal and central electrode positions. Results During the NREM sleep, the power spectra did not differ between groups in the prefrontal cortex; while primary insomnia patients exhibited a higher beta power spectrum and a lower delta power spectrum compared to good sleepers in other areas. During the REM sleep, the beta1 power spectrum was lower in the prefrontal cortex in primary insomnia patients compared to good sleepers; while no significant difference between groups was obtained for the other areas. Conclusions The present study shows a specific prefrontal sleep pattern during the whole sleep period. In addition, we suggest that primary insomnia patients displayed a dysfunction in the reactivation of the limbic system during the REM sleep and we give additional arguments in favor of a sleep-protection mechanism displayed by primary insomnia patients. PMID:25611059

Perrier, Joy; Clochon, Patrice; Bertran, Françoise; Couque, Colette; Bulla, Jan; Denise, Pierre; Bocca, Marie-Laure

2015-01-01

250

Attention modulates spatial priority maps in the human occipital, parietal and frontal cortices  

PubMed Central

Computational theories propose that attention modulates the topographical landscape of spatial ‘priority’ maps in regions of visual cortex so that the location of an important object is associated with higher activation levels. While single-unit recording studies have demonstrated attention-related increases in the gain of neural responses and changes in the size of spatial receptive fields, the net effect of these modulations on the topography of region-level priority maps has not been investigated. Here, we used fMRI and a multivariate encoding model to reconstruct spatial representations of attended and ignored stimuli using activation patterns across entire visual areas. These reconstructed spatial representations reveal the influence of attention on the amplitude and size of stimulus representations within putative priority maps across the visual hierarchy. Our results suggest that attention increases the amplitude of stimulus representations in these spatial maps, particularly in higher visual areas, but does not substantively change their size. PMID:24212672

Sprague, Thomas C.; Serences, John T.

2014-01-01

251

Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles  

PubMed Central

We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles (ADDWOC) and detected a mutation in the extracellular matrix protein encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1 binding partner. Structural modeling the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the extracellular matrix in the pathogenesis of Dandy-Walker spectrum disorders. PMID:23674478

Darbro, Benjamin W.; Mahajan, Vinit B.; Gakhar, Lokesh; Skeie, Jessica M.; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J.; Dobyns, William B.; Kessler, John A.; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J. Robert; Aldinger, Kimerbly A.; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M.; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J.; Bassuk, Alexander G.

2013-01-01

252

Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles.  

PubMed

We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles and detected a mutation in the extracellular matrix (ECM) protein-encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1-binding partner. Structural modeling of the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the ECM in the pathogenesis of Dandy-Walker spectrum disorders. PMID:23674478

Darbro, Benjamin W; Mahajan, Vinit B; Gakhar, Lokesh; Skeie, Jessica M; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J; Dobyns, William B; Kessler, John A; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J Robert; Aldinger, Kimerbly A; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J; Bassuk, Alexander G

2013-08-01

253

Sensory-specific anomic aphasia following left occipital lesions: Data from free oral descriptions of concrete word meanings  

PubMed Central

The present study investigated hierarchical lexical semantic structure in oral descriptions of concrete word meanings produced by a subject (ZZ) diagnosed with anomic aphasia due to left occipital lesions. The focus of the analysis was production of a) nouns at different levels of semantic specificity (e.g., “robin”–“bird”–“animal”) and b) words describing sensory or motor experiences (e.g., “blue,” “soft,” “fly”). Results show that in contrast to healthy and aphasic controls, who produced words at all levels of specificity and mainly vision-related sensory information, ZZ produced almost exclusively nouns at the most non-specific levels and words associated with sound and movement. PMID:23425233

Mårtensson, F.; Roll, M.; Lindgren, M.; Apt, P.; Horne, M.

2013-01-01

254

Acquired Chiari malformation secondary to atlantoaxial vertical subluxation in a patient with rheumatoid arthritis combined with atlanto-occipital assimilation.  

PubMed

A 65-year-old woman with a history of rheumatoid arthritis presented with a rare case of acquired Chiari malformation secondary to atlantoaxial vertical subluxation, associated with congenital atlanto-occipital assimilation. Syringomyelia and tetraparesis improved immediately after posterior fossa decompression and simultaneous occipito-cervical junction fusion. The progression of acquired Chiari malformation is not well known. We concluded that coexisting assimilation accelerated crowded foramen magnum following atlantoaxial vertical subluxation and induced acquired Chiari malformation over the course of a few years. PMID:23006887

Kimura, Yuiko; Seichi, Atsushi; Gomi, Akira; Kojima, Masahiro; Inoue, Hirokazu; Kimura, Atsushi

2012-01-01

255

Childhood epilepsy with occipital paroxysms: difficulties in distinct segregation into either the early-onset or late-onset epilepsy subtypes.  

PubMed

The Commission on Classification and Terminology of the International League Against Epilepsy Childhood rigidly segregated epilepsy with occipital paroxysms into 2 separate syndromes with different predominant seizure types: early-onset seizure susceptibility type consisting of prolonged infrequent, nocturnal autonomic seizures and accompanied by eye deviation and ictal vomiting and late onset with short diurnal frequent seizures and visual ictal manifestations along with throbbing headaches. Epileptic clinical manifestations and electroencephalographic data were analyzed in 28 patients with suspected occipital lobe epilepsy in an attempt to segregate them into either the early or late forms according to the International League Against Epilepsy classification. Electroencephalography in 25 children demonstrated occipital epileptiform paroxysms compatible with the suspected epileptic syndrome. Only 14 (50%) children complied with the rigid criteria of either early-onset or late-onset presentations. The other 14 (50%) children presented with mixed diverse epileptic phenomena such as short-lived seizures in infancy or prolonged seizures during childhood, not complying with either rigid syndrome (ie, short-lived epileptic blindness at an early age or vomiting during later childhood). Despite present attempts to rigidly segregate childhood epilepsy with occipital paroxysms into 2 distinct epileptic syndromes, a high percentage of children still present with various mixed clinical phenomena. Therefore, clinicians should be aware of possible unique and unusual presentations of occipital lobe epilepsy at various ages. PMID:17690066

Genizi, Jacob; Zelnik, Nathanel; Ravid, Sarit; Shahar, Eli

2007-05-01

256

Small bowel volvulus after transabdominal preperitoneal hernia repair due to improper use of V-Loc™ barbed absorbable wire – do we always “read the instructions first”?  

PubMed Central

Introduction Transabdominal preperitoneal endoscopic hernia repair (TAPP) is part of primary surgical health care. While both, the reported recurrence rate and procedure specific morbidity are consistently low, rare serious complications occur. Presentiation of case A 36-year-old male patient developed bowel obstruction three days after both-sided TAPP for inguinal hernia repair. A computer tomography scan of the abdomen revealed a small bowel volvulus in the right lower quadrant of the abdomen requiring urgent revisional surgery. Intraoperatively, the small bowel and its mesenterial vessels were found to be twisted around a 5 cm long V-Loc™ barbed absorbable suturing wire. After successful laparoscopic adhesiolysis, removal of the wire and detorquing of the bowel conglomerate, resection of small intestine was not necessary. The patient's further postoperative recovery was uneventful. Discussion Due to the barbed configuration of the V-Loc™ wire, a gapless continuous suturing of the peritoneum without laparoscopic knotting is easily and fast to accomplish. In this case the recommendation of the manufacturer to shorten the wire was not strictly followed and neither had the suture stump been extraperitonealized in order to avoid such rare complications. Conclusion Surgeons need to be aware of relevant “tricks and traps” of routinely performed procedures and have to know all tools and material they use very well. This case may therefore increase our attention when it comes to little things which actually do matter. PMID:25704567

Filser, Joerg; Reibetanz, Joachim; Krajinovic, Katica; Germer, Christoph-Thomas; Dietz, Ulrich Andreas; Seyfried, Florian

2015-01-01

257

The multifunctional application of microfluidic lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS) within the field of bioanalytics  

NASA Astrophysics Data System (ADS)

This contribution will present a variety of applications of lab-on-a-chip surface enhanced Raman spectroscopy in the field of bioanalytic. Beside the quantification and online monitoring of drugs and pharmaceuticals, determination of enzyme activity and discrimination of bacteria are successfully carried out utilizing LOC-SERS. The online-monitoring of drugs using SERS in a microfluidic device is demonstrated for nicotine. The enzyme activity of thiopurine methyltransferase (TPMT) in lysed red blood cells is determined by SERS in a lab-on-a-chip device. To analyse the activity of TPMT the metabolism of 6-mercaptopurine to 6-methylmercaptopurine is investigated. The discrimination of bacteria on strain level is carried out with different E. coli strains. For the investigations, the bacteria are busted by ultra sonic to achieve a high information output. This sample preparation provides the possibility to detect SERS spectra containing information of the bacterial cell walls as well as of the cytoplasm. This contribution demonstrates the great potential of LOC-SERS in the field of bioanalytics.

März, Anne; Mönch, Bettina; Walter, Angela; Bocklitz, Thomas; Schumacher, Wilm; Rösch, Petra; Kiehntopf, Michael; Popp, Jürgen

2011-07-01

258

Chromosome 11: Ubiquilin 3 and LOC genes affecting smell, 3D animation with no audioSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

DNAi location: Genome>Tour>flyover>Ubiquilin and olfactory receptor cluster The intergenic region is followed by two adjacent ubiquilin genes, which are involved in key cell processes, from replication to \\"programmed\\" death. Ubiquilin 3 is expressed specifically in the testis, where it is believed to help regulate sperm development. These are followed by a cluster of gene locations (LOC) thought to encode olfactory receptors, which receive stimuli in the nose to allow us to detect smells. At 31,110 nucleotides long, the first gene in this cluster, LOC120009, is the longest we will encounter on our journey. Its 11 coding exons are indicated in red, but most of its bulk comes from its yellow introns and 29 blue and purple transposons. However, the majority of olfactory receptors are short. The next four gene locations are more typical of olfactory receptors in having only one or two coding exons. About 60% of our smell receptors are nonfunctional. Presumably, humans have less need for smell in locating food and interacting socially. The mutations that inactivate many receptors vary among people, meaning that there is a DNA basis for the observation that some people can smell better than others! It also suggests that the loss of smelling acuity has occurred very recently in human evolution and is still ongoing.

2008-10-06

259

[Features of cortex areas system interactions in the left and right brain hemospheres during different human sleep stages].  

PubMed

The article is devoted to analysis of research brain biopotential field structure during different stages of natural night sleep in adults. The special attention is given to distinctions of the spatial organization of EEG interregional relations in the left and right hemispheres which are shown most strongly in the II and III sleep stages. The special role of frontal cortical areas in reorganization of brain system activity during falling asleep is highlighted. Essential strengthening of hemispherical interaction of cortex biopotentials fluctuations during falling asleep--a stage of I(B)--along with its reduction in central and occipital cortical areas is shown during a slow wave sleep (II--IV stage) versus wakefulness. PMID:23401917

Shepoval'nikov, A N; Tsitseroshin, M N; Za?tseva, L G; Gal'perina, E I

2012-10-01

260

Touch activates human auditory cortex.  

PubMed

Vibrotactile stimuli can facilitate hearing, both in hearing-impaired and in normally hearing people. Accordingly, the sounds of hands exploring a surface contribute to the explorer's haptic percepts. As a possible brain basis of such phenomena, functional brain imaging has identified activations specific to audiotactile interaction in secondary somatosensory cortex, auditory belt area, and posterior parietal cortex, depending on the quality and relative salience of the stimuli. We studied 13 subjects with non-invasive functional magnetic resonance imaging (fMRI) to search for auditory brain areas that would be activated by touch. Vibration bursts of 200 Hz were delivered to the subjects' fingers and palm and tactile pressure pulses to their fingertips. Noise bursts served to identify auditory cortex. Vibrotactile-auditory co-activation, addressed with minimal smoothing to obtain a conservative estimate, was found in an 85-mm3 region in the posterior auditory belt area. This co-activation could be related to facilitated hearing at the behavioral level, reflecting the analysis of sound-like temporal patterns in vibration. However, even tactile pulses (without any vibration) activated parts of the posterior auditory belt area, which therefore might subserve processing of audiotactile events that arise during dynamic contact between hands and environment. PMID:16488157

Schürmann, Martin; Caetano, Gina; Hlushchuk, Yevhen; Jousmäki, Veikko; Hari, Riitta

2006-05-01

261

Frontal Eye Fields Control Attentional Modulation of Alpha and Gamma Oscillations in Contralateral Occipitoparietal Cortex  

PubMed Central

Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8–12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted contralaterally and attenuated ipsilaterally. These modulations must be under top-down control; however, the control mechanisms are not yet fully understood. Here we investigated the causal contribution of the human frontal eye field (FEF) by combining repetitive transcranial magnetic stimulation (TMS) with subsequent magnetoencephalography. Following inhibitory theta burst stimulation to the left FEF, right FEF, or vertex, participants performed a visual discrimination task requiring covert attention to either visual hemifield. Both left and right FEF TMS caused marked attenuation of alpha modulation in the occipitoparietal cortex. Notably, alpha modulation was consistently reduced in the hemisphere contralateral to stimulation, leaving the ipsilateral hemisphere relatively unaffected. Additionally, right FEF TMS enhanced gamma modulation in left visual cortex. Behaviorally, TMS caused a relative slowing of response times to targets contralateral to stimulation during the early task period. Our results suggest that left and right FEF are causally involved in the attentional top-down control of anticipatory alpha power in the contralateral visual system, whereas a right-hemispheric dominance seems to exist for control of stimulus-induced gamma power. These findings contrast the assumption of primarily intrahemispheric connectivity between FEF and parietal cortex, emphasizing the relevance of interhemispheric interactions. The contralaterality of effects may result from a transient functional reorganization of the dorsal attention network after inhibition of either FEF. PMID:25632139

O'Shea, Jacinta; Jensen, Ole; Bergmann, Til O.

2015-01-01

262

An analysis of von Economo neurons in the cerebral cortex of cetaceans, artiodactyls, and perissodactyls.  

PubMed

Von Economo neurons (VENs) are specialized projection neurons with a characteristic spindle-shaped soma and thick basal and apical dendrites. VENs have been described in restricted cortical regions, with their most frequent appearance in layers III and V of the anterior cingulate cortex, anterior insula, and frontopolar cortex of humans, great apes, macaque monkeys, elephants, and some cetaceans. Recently, a ubiquitous distribution of VENs was reported in various cortical areas in the pygmy hippopotamus, one of the closest living relatives of cetaceans. That finding suggested that VENs might not be unique to only a few species that possess enlarged brains. In the present analysis, we assessed the phylogenetic distribution of VENs within species representative of the superordinal clade that includes cetartiodactyls and perissodactyls, as well as afrotherians. In addition, the distribution of fork cells that are often found in close proximity to VENs was also assessed. Nissl-stained sections from the frontal pole, anterior cingulate cortex, anterior insula, and occipital pole of bowhead whale, cow, sheep, deer, horse, pig, rock hyrax, and human were examined using stereologic methods to quantify VENs and fork cells within layer V of all four cortical regions. VENs and fork cells were found in each of the species examined here with species-specific differences in distributions and densities. The present results demonstrated that VENs and fork cells were not restricted to highly encephalized or socially complex species, and their repeated emergence among distantly related species seems to represent convergent evolution of specialized pyramidal neurons. The widespread phylogenetic presence of VENs and fork cells indicates that these neuron morphologies readily emerged in response to selective forces,whose variety and nature are yet to be identified. PMID:24852852

Raghanti, Mary Ann; Spurlock, Linda B; Robert Treichler, F; Weigel, Sara E; Stimmelmayr, Raphaela; Butti, Camilla; Hans Thewissen, J G M; Hof, Patrick R

2014-05-23

263

Investigating Representations of Facial Identity in Human Ventral Visual Cortex with Transcranial Magnetic Stimulation  

PubMed Central

The occipital face area (OFA) is face-selective. This enhanced activation to faces could reflect either generic face and shape-related processing or high-level conceptual processing of identity. Here we examined these two possibilities using a state-dependent transcranial magnetic stimulation (TMS) paradigm. The lateral occipital (LO) cortex which is activated non-selectively by various types of objects served as a control site. We localized OFA and LO on a per-participant basis using functional MRI. We then examined whether TMS applied to either of these regions affected the ability of participants to decide whether two successively presented and physically different face images were of the same famous person or different famous people. TMS was applied during the delay between first and second face presentations to investigate whether neuronal populations in these regions played a causal role in mediating the behavioral effects of identity repetition. Behaviorally we found a robust identity repetition effect, with shorter reaction times (RTs) when identity was repeated, regardless of the fact that the pictures were physically different. Surprisingly, TMS applied over LO (but not OFA) modulated overall RTs, compared to the No-TMS condition. But critically, we found no effects of TMS to either area that were modulated by identity repetition. Thus, we found no evidence to suggest that OFA or LO contain neuronal representations selective for the identity of famous faces which play a causal role in identity processing. Instead, these brain regions may be involved in the processing of more generic features of their preferred stimulus categories. PMID:20631842

Gilaie-Dotan, Sharon; Silvanto, Juha; Schwarzkopf, Dietrich S.; Rees, Geraint

2010-01-01

264

?-Aminobutyric acid (GABA) concentration inversely correlates with basal perfusion in human occipital lobe.  

PubMed

Commonly used neuroimaging approaches in humans exploit hemodynamic or metabolic indicators of brain function. However, fundamental gaps remain in our ability to relate such hemo-metabolic reactivity to neurotransmission, with recent reports providing paradoxical information regarding the relationship among basal perfusion, functional imaging contrast, and neurotransmission in awake humans. Here, sequential magnetic resonance spectroscopy (MRS) measurements of the primary inhibitory neurotransmitter, ?-aminobutyric acid (GABA+macromolecules normalized by the complex N-acetyl aspartate-N-acetyl aspartyl glutamic acid: [GABA(+)]/[NAA-NAAG]), and magnetic resonance imaging (MRI) measurements of perfusion, fractional gray-matter volume, and arterial arrival time (AAT) are recorded in human visual cortex from a controlled cohort of young adult male volunteers with neurocognitive battery-confirmed comparable cognitive capacity (3?T; n=16; age=23±3 years). Regression analyses reveal an inverse correlation between [GABA(+)]/[NAA-NAAG] and perfusion (R=-0.46; P=0.037), yet no relationship between AAT and [GABA(+)]/[NAA-NAAG] (R=-0.12; P=0.33). Perfusion measurements that do not control for AAT variations reveal reduced correlations between [GABA(+)]/[NAA-NAAG] and perfusion (R=-0.13; P=0.32). These findings largely reconcile contradictory reports between perfusion and inhibitory tone, and underscore the physiologic origins of the growing literature relating functional imaging signals, hemodynamics, and neurotransmission. PMID:24398941

Donahue, Manus J; Rane, Swati; Hussey, Erin; Mason, Emily; Pradhan, Subechhya; Waddell, Kevin W; Ally, Brandon A

2014-03-01

265

Temporal coding in the auditory cortex.  

PubMed

Speech is a complex acoustic signal showing a quasiperiodic structure at several timescales. Integrated neural signals recorded in the cortex also show periodicity at different timescales. In this chapter we outline the neural mechanisms that potentially allow the auditory cortex to segment and encode continuous speech. This chapter focuses on how the human auditory cortex uses the temporal structure of the acoustic signal to extract phonemes and syllables, the two major constituents of connected speech. We argue that the quasiperiodic structure of collective neural activity in auditory cortex represents the ideal mechanical infrastructure to fractionate continuous speech into linguistic constituents of variable sizes. PMID:25726264

Arnal, Luc H; Poeppel, David; Giraud, Anne-Lise

2015-01-01

266

Image-Guided Stereotactic Body Radiotherapy for Lung Tumors Using BodyLoc With Tomotherapy: Clinical Implementation and Set-Up Accuracy  

SciTech Connect

We investigated the use of a BodyLoc immobilization and stereotactic localization device combined with TomoTherapy megavoltage CT (MVCT) in lung stereotactic body radiotherapy (SBRT) to reduce set-up uncertainty and treatment time. Eight patients treated with 3-5 fractions of SBRT were retrospectively analyzed. A BodyLoc localizer was used in both CT simulation for localization and the initial patient treatment set-up. Patients were immobilized with a vacuum cushion on the back and a thermoplastic body cast on the anterior body. Pretreatment MVCT from the TomoTherapy unit was fused with the planning kilovoltage CT (KVCT) before each fraction of treatment to determine interfractional set-up error. The comparison of two MVCTs during a fraction of treatment resulted in the intrafractional uncertainty of the treatment. A total of 224 target isocenter shifts were analyzed to assess these inter- and intrafractional tumor motions. We found that for interfractional shifts, the mean set-up errors and standard deviations were -1.1 {+-} 2.8 mm, -2.5 {+-} 8.7 mm, and 4.1 {+-} 2.6 mm, for lateral, longitudinal, and vertical variation, respectively; the mean setup rotational variation was -0.3 {+-} 0.7 deg.; and the maximum motion was 13.5 mm in the longitudinal direction. For intrafractional shifts, the mean set-up errors and standard deviations were -0.1 {+-} 0.7 mm, -0.3 {+-} 2.0 mm, and 0.5 {+-} 1.1 mm for the lateral, longitudinal, and vertical shifts, respectively; the mean rotational variation was 0.1 {+-} 0.2 deg.; and the maximum motion was 3.8 mm in the longitudinal direction. There was no correlation among patient characteristics, set-up uncertainties, and isocenter shifts, and the interfractional set-up uncertainties were larger than the intrafractional isocenter shift. The results of this study suggested that image-guided stereotactic body radiotherapy using the BodyLoc immobilization system with TomoTherapy can improve treatment accuracy.

Zhou Jining [Center for Cancer Treatment, Sharp Grossmont Hospital, La Mesa, CA (United States); Virginia Commonwealth University, Richmond, VA (United States); Mount Sinai Medical Center, New York, NY (United States)], E-mail: jining.zhou@sharp.com; Uhl, Barry; Dewitt, Kelly; Young, Mark; Taylor, Brian; Fei Dingyu; Lo, Y-C [Center for Cancer Treatment, Sharp Grossmont Hospital, La Mesa, CA (United States); Virginia Commonwealth University, Richmond, VA (United States); Mount Sinai Medical Center, New York, NY (United States)

2010-04-01

267

TOP-DOWN CONTROL OF MOTOR CORTEX ENSEMBLES BY DORSOMEDIAL PREFRONTAL CORTEX  

PubMed Central

SUMMARY Dorsomedial prefrontal cortex is critical for the temporal control of behavior. Dorsomedial prefrontal cortex might alter neuronal activity in areas such as motor cortex to inhibit temporally inappropriate responses. We tested this hypothesis by recording from neuronal ensembles in rodent dorsomedial prefrontal cortex during a delayed-response task. One-third of dorsomedial prefrontal neurons were significantly modulated during the delay period. The activity of many of these neurons was predictive of premature responding. We then reversibly inactivated dorsomedial prefrontal cortex while recording ensemble activity in motor cortex. Inactivation of dorsomedial prefrontal cortex reduced delay-related firing, but not response-related firing, in motor cortex. Finally, we made simultaneous recordings in dorsomedial prefrontal cortex and motor cortex and found strong delay-related temporal correlations between neurons in the two cortical areas. These data suggest that functional interactions between dorsomedial prefrontal cortex and motor cortex might serve as a top-down control signal that inhibits inappropriate responding. PMID:17145511

Narayanan, Nandakumar S.; Laubach, Mark

2007-01-01

268

Frontal cortex TMS for tinnitus.  

PubMed

Both invasive and non-invasive neuromodulation of the dorsolateral prefrontal cortex (DLPFC) are capable of suppressing tinnitus loudness. Repetitive transcranial magnetic stimulation (rTMS) of the DLPFC has an add-on effect for auditory cortex (AC) rTMS in improving tinnitus-related distress. We aimed to investigate whether TMS and rTMS of the DLPFC is capable of reducing tinnitus loudness and what mechanism might be involved. Two TMS studies targeting the right DLPFC were performed. Study 1 investigated 44 tinnitus patients who underwent either 1 or 10 Hz real or sham TMS (200 pulses at 80% motor threshold). In Study 2 we performed rTMS (10 sessions of 600 pulses) in responders of study 1. Changes on the visual analog scale (VAS) loudness were evaluated. All patients underwent a pre-TMS electroencephalography: differences in functional connectivity between responders and non-responders were evaluated using sLORETA. Only 1 Hz TMS was capable of significantly reducing tinnitus loudness for 11 patients with a mean suppression of 39.23%. RTMS for these 11 patients yielded a 21% improvement in VAS loudness, and in 7 of 11 rTMS was successful, with, a mean suppression of 27.13%. The responders were characterized by a difference in lagged linear connectivity in the theta band among the DLPFC, anterior cingulate cortex (ACC), parahippocampus and AC. In summary, 1 H, TMS and rTMS of the right DLPFC can transiently reduce the perceived tinnitus loudness mediated via functional connections between the DLPFC and a network consisting of the ACC, parahippocampus and AC. PMID:22853891

De Ridder, Dirk; Song, Jae-Jin; Vanneste, Sven

2013-05-01

269

13C MRS of occipital and frontal lobes at 3 T using a volume coil for stochastic proton decoupling  

PubMed Central

Previously, we devised a novel strategy for in vivo 13C MRS using [2-13C]glucose infusion and low-power proton decoupling, and proposed that this strategy could be used to acquire 13C MR spectra from the frontal lobe of the human brain. Here, we demonstrate, for the first time, in vivo 13C MRS of human frontal lobe acquired at 3 T. Because the primary metabolites of [2-13C]glucose can be decoupled using very-low-radiofrequency power, we used a volume coil for proton decoupling in this study. The homogeneous B1 field of the volume coil was found to significantly enhance the decoupling efficiency of the stochastic decoupling sequence. Detailed specific absorption rates inside the human head were analyzed using the finite difference time domain method to ensure experimental safety. In vivo 13C spectra from the occipital and frontal lobes of the human brain were obtained. At a decoupling power of 30 W (time-averaged power, 2.45 W), the spectra from the occipital lobe showed well-resolved spectral resolution and excellent signal-to-noise ratio. Although frontal lobe 13C spectra were affected by local B0 field inhomogeneity, we demonstrated that the spectral quality could be improved using post-acquisition data processing. In particular, we showed that the frontal lobe glutamine C5 at 178.5 ppm and aspartate C4 at 178.3 ppm could be spectrally resolved with effective proton decoupling and B0 field correction. Because of its large spatial coverage, volume coil decoupling provides the potential to acquire 13C MRS from more than one brain region simultaneously. PMID:20878974

Li, Shizhe; Zhang, Yan; Wang, Shumin; Araneta, Maria Ferraris; Johnson, Christopher S.; Xiang, Yun; Innis, Robert B.; Shen, Jun

2011-01-01

270

Progressive Cognitive Impairment Evolving to Dementia Parallels Parieto-Occipital and Temporal Enlargement in Idiopathic Chronic Hydrocephalus: A Retrospective Cohort Study  

PubMed Central

Little is known regarding progressive enlargement of the ventricular system in symptomatic patients or asymptomatic subjects. Before eventual surgical treatment, we evaluated the clinical and radiological features of an extremely rare group of patients with idiopathic chronic hydrocephalus (ICH) and cognitive impairment evolving to dementia (n?=?11), and an extremely rare group of asymptomatic or minimally symptomatic adults (AMSA) with ventricular enlargement (n?=?10). We quantified changes over time in the ventricular frontal, occipital, and temporal horns by measuring the Evans’ index plus a parieto-occipital ratio and a temporal ratio, and their percentage of progression. Cerebral ventricles expanded over very long term in both demented patients with ICH and in AMSA. In AMSA, frontal enlargement predominated, whereas demented patients showed predominant parieto-occipital (p?=?0.00) and temporal (p?=?0.00) enlargement that progressed faster than in AMSA (p?=?0.00). In ICH, progression of cognitive impairment parallels ventricular parieto-occipital and temporal horn enlargement. Limitations of this study are the retrospective nature, the non-uniform use of neuropsychological tests, the reduced sample size due to the extremely stringent enrollment criteria, the inability to determine the precise rate of progression. PMID:25759681

Missori, Paolo; Currà, Antonio

2015-01-01

271

Prefrontal cortex glutamate and extraversion  

PubMed Central

Extraversion is considered one of the core traits of personality. Low extraversion has been associated with increased vulnerability to affective and anxiety disorders. Brain imaging studies have linked extraversion, approach behaviour and the production of positive emotional states to the dorsolateral prefrontal cortex (DLPFC) and glutamatergic neurotransmission. However, the relationship between extraversion and glutamate in the DLPFC has not been investigated so far. In order to address this issue, absolute glutamate concentrations in the DLPFC and the visual cortex as a control region were measured by 3-Tesla proton magnetic resonance spectroscopy (1H-MRS) in 29 subjects with high and low extraversion. We found increased glutamate levels in the DLPFC of introverts as compared with extraverts. The increased glutamate concentration was specific for the DLPFC and negatively associated with state anxiety. Although preliminary, results indicate altered top-down control of DLPFC due to reduced glutamate concentration as a function of extraversion. Glutamate measurement with 1H-MRS may facilitate the understanding of biological underpinnings of personality traits and psychiatric diseases associated with dysfunctions in approach behaviour and the production of positive emotional states. PMID:22016442

Schubert, Florian; Jaedke, Maren; Gallinat, Jürgen; Bajbouj, Malek

2012-01-01

272

Mapping Prefrontal Cortex Functions in Human Infancy  

ERIC Educational Resources Information Center

It has long been thought that the prefrontal cortex, as the seat of most higher brain functions, is functionally silent during most of infancy. This review highlights recent work concerned with the precise mapping (localization) of brain activation in human infants, providing evidence that prefrontal cortex exhibits functional activation much…

Grossmann, Tobias

2013-01-01

273

Subspecialization in the human posterior medial cortex.  

PubMed

The posterior medial cortex (PMC) is particularly poorly understood. Its neural activity changes have been related to highly disparate mental processes. We therefore investigated PMC properties with a data-driven exploratory approach. First, we subdivided the PMC by whole-brain coactivation profiles. Second, functional connectivity of the ensuing PMC regions was compared by task-constrained meta-analytic coactivation mapping (MACM) and task-unconstrained resting-state correlations (RSFC). Third, PMC regions were functionally described by forward/reverse functional inference. A precuneal cluster was mostly connected to the intraparietal sulcus, frontal eye fields, and right temporo-parietal junction; associated with attention and motor tasks. A ventral posterior cingulate cortex (PCC) cluster was mostly connected to the ventromedial prefrontal cortex and middle left inferior parietal cortex (IPC); associated with facial appraisal and language tasks. A dorsal PCC cluster was mostly connected to the dorsomedial prefrontal cortex, anterior/posterior IPC, posterior midcingulate cortex, and left dorsolateral prefrontal cortex; associated with delay discounting. A cluster in the retrosplenial cortex was mostly connected to the anterior thalamus and hippocampus. Furthermore, all PMC clusters were congruently coupled with the default mode network according to task-unconstrained but not task-constrained connectivity. We thus identified distinct regions in the PMC and characterized their neural networks and functional implications. PMID:25462801

Bzdok, Danilo; Heeger, Adrian; Langner, Robert; Laird, Angela R; Fox, Peter T; Palomero-Gallagher, Nicola; Vogt, Brent A; Zilles, Karl; Eickhoff, Simon B

2015-02-01

274

The Frontal Cortex and Exogenous Attentional Orienting  

E-print Network

orienting system. These results suggest that the dorsolateral prefrontal cortex plays an important role to different parts of the dorsolateral prefrontal cortex. & INTRODUCTION The human visual system is constantly not to affect the early facilitation effects of exogenous cues. Second, dorsolateral prefrontal damage

Chatterjee, Anjan

275

Dissociating motor cortex from the motor  

PubMed Central

Abstract During closed-loop control of a brain–computer interface, neurons in the primary motor cortex can be intensely active even though the subject may be making no detectable movement or muscle contraction. How can neural activity in the primary motor cortex become dissociated from the movements and muscles of the native limb that it normally controls? Here we examine circumstances in which motor cortex activity is known to dissociate from movement – including mental imagery, visuo-motor dissociation and instructed delay. Many such motor cortex neurons may be related to muscle activity only indirectly. Furthermore, the integration of thousands of synaptic inputs by individual ?-motoneurons means that under certain circumstances even cortico-motoneuronal cells, which make monosynaptic connections to ?-motoneurons, can become dissociated from muscle activity. The natural ability of motor cortex neurons under voluntarily control to become dissociated from bodily movement may underlie the utility of this cortical area for controlling brain–computer interfaces. PMID:22005673

Schieber, Marc H

2011-01-01

276

Global optimization of cerebral cortex layout  

PubMed Central

Functional areas of mammalian cerebral cortex seem positioned to minimize costs of their interconnections, down to a best-in-a-billion optimality level. The optimization problem here, originating in microcircuit design, is: Given connections among components, what is the physical placement of the components on a surface that minimizes total length of connections? Because of unfeasibility of measuring long-range “wire length” in the cortex, a simpler adjacency cost was validated. To deal with incomplete information on brain networks, a size law was developed that predicts optimization patterns in subnetworks. Macaque and cat cortex rank better in this connection optimization than the wiring of comparably structured computer chips, but somewhat worse than the macroeconomic commodity-flow network among U.S. states. However, cortex wiring conforms to the size law better than the macroeconomic patterns, which may indicate cortex optimizing mechanisms involve more global processes. PMID:14722353

Cherniak, Christopher; Mokhtarzada, Zekeria; Rodriguez-Esteban, Raul; Changizi, Kelly

2004-01-01

277

Ventral occipital lesions impair object recognition but not object-directed grasping: an fMRI study  

E-print Network

on the same visual input inspired a novel interpretation of the functions of the two main cortical visual considerable atrophy in some regions of the parietal lobes. In par- ticular, an area in the anterior, and the dorsal stream, which also arises in area V1 but projects instead to the posterior parietal cortex

James, Thomas

278

Useful signals from motor cortex  

PubMed Central

Historically, the motor cortical function has been explained as a funnel to muscle activation. This invokes the idea that motor cortical neurons, or ‘upper motoneurons’, directly cause muscle contraction just like spinal motoneurons. Thus, the motor cortex and muscle activity are inextricably entwined like a puppet master and his marionette. Recently, this concept has been challenged by current experimentation showing that many behavioural aspects of action are represented in motor cortical activity. Although this activity may still be related to muscle activation, the relation between the two is likely to be indirect and complex, whereas the relation between cortical activity and kinematic parameters is simple and robust. These findings show how to extract useful signals that help explain the underlying process that generates behaviour and to harness these signals for potentially therapeutic applications. PMID:17255162

Schwartz, Andrew B

2007-01-01

279

Addiction and the adrenal cortex  

PubMed Central

Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion. PMID:23825159

Vinson, Gavin P; Brennan, Caroline H

2013-01-01

280

Addiction and the adrenal cortex.  

PubMed

SUBSTANTIAL EVIDENCE SHOWS THAT THE HYPOPHYSEAL-PITUITARY-ADRENAL (HPA) AXIS AND CORTICOSTEROIDS ARE INVOLVED IN THE PROCESS OF ADDICTION TO A VARIETY OF AGENTS, AND THE ADRENAL CORTEX HAS KEY ROLE. IN GENERAL, PLASMA CONCENTRATIONS OF CORTISOL (OR CORTICOSTERONE IN RATS OR MICE) RISE ON DRUG WITHDRAWAL IN A MANNER THAT SUGGESTS CORRELATION WITH THE BEHAVIOURAL AND SYMPTOMATIC SEQUELAE BOTH IN MAN AND IN EXPERIMENTAL ANIMALS. CORTICOSTEROID LEVELS FALL BACK TO NORMAL VALUES IN RESUMPTION OF DRUG INTAKE. THE POSSIBLE INTERACTIONS BETWEEN BRAIN CORTICOTROPHIN RELEASING HORMONE (CRH) AND PROOPIOMELANOCORTIN (POMC) PRODUCTS AND THE SYSTEMIC HPA, AND ADDITIONALLY WITH THE LOCAL CRH-POMC SYSTEM IN THE ADRENAL GLAND ITSELF, ARE COMPLEX. NEVERTHELESS, THE EVIDENCE INCREASINGLY SUGGESTS THAT ALL MAY BE INTERLINKED AND THAT CRH IN THE BRAIN, AND BRAIN POMC PRODUCTS INTERACT WITH THE BLOOD-BORNE HPA DIRECTLY OR INDIRECTLY. CORTICOSTEROIDS THEMSELVES ARE KNOWN TO AFFECT MOOD PROFOUNDLY, AND MAY THEMSELVES BE ADDICTIVE. ADDITIONALLY, THERE IS A HEIGHTENED SUSCEPTIBILITY FOR ADDICTED SUBJECTS TO RELAPSE IN CONDITIONS THAT ARE ASSOCIATED WITH CHANGE IN HPA ACTIVITY, SUCH AS IN STRESS, OR AT DIFFERENT TIMES OF DAY. RECENT STUDIES GIVE COMPELLING EVIDENCE THAT A SIGNIFICANT PART OF THE ARRAY OF ADDICTIVE SYMPTOMS IS DIRECTLY ATTRIBUTABLE TO THE SECRETORY ACTIVITY OF THE ADRENAL CORTEX AND THE ACTIONS OF CORTICOSTEROIDS. ADDITIONALLY, SEX DIFFERENCES IN ADDICTION MAY ALSO BE ATTRIBUTABLE TO ADRENOCORTICAL FUNCTION: in humans males may be protected through higher secretion of dehydroepiandrosterone (and its sulphate) and in rats females may be more susceptible because of higher corticosterone secretion. PMID:23825159

Vinson, Gavin P; Brennan, Caroline H

2013-05-31

281

Seeing with Profoundly Deactivated Mid-level Visual Areas: Non-hierarchical Functioning in the Human Visual Cortex  

PubMed Central

A fundamental concept in visual processing is that activity in high-order object-category distinctive regions (e.g., lateral occipital complex, fusiform face area, middle temporal+) is dependent on bottom-up flow of activity in earlier retinotopic areas (V2, V3, V4) whose main input originates from primary visual cortex (V1). Thus, activity in down stream areas should reflect lower-level inputs. Here we qualify this notion reporting case LG, a rare case of developmental object agnosia and prosopagnosia. In this person, V1 was robustly activated by visual stimuli, yet intermediate areas (V2–V4) were strongly deactivated. Despite this intermediate deactivation, activity in down stream visual areas remained robust, showing selectivity for houses and places, while selectivity for faces and objects was impaired. The extent of impairment evident in functional magnetic resonance imaging and electroencephalography activations was somewhat larger in the left hemisphere. This pattern of brain activity, coupled with fairly adequate everyday visual performance is compatible with models emphasizing the role of nonlinear local “amplification” of neuronal inputs in eliciting activity in ventral and dorsal visual pathways as well as perceptual experience in the human brain. Thus, while the proper functioning of intermediate areas appears essential for specialization in the cortex, daily visual behavior and reading are maintained even with deactivated intermediate visual areas. PMID:19015369

Gilaie-Dotan, Sharon; Perry, Anat; Bonneh, Yoram; Malach, Rafael

2009-01-01

282

The similarities between the hallucinations associated with the partial epileptic seizures of the occipital lobe and ball lightning observations  

NASA Astrophysics Data System (ADS)

Ball Lightning was seen and described since antiquity and recorded in many places. Ball lightning is usually observed during thunderstorms but large number of ball lightning observations is also reported during fine weather without any connection to thunderstorms or lightning. However, so far no one has managed to generate them in the laboratory. It is photographed very rarely and in many cases the authenticity of them is questionable. It is possible that many different phenomena are grouped together and categorized simply as ball lightning. Indeed, the visual hallucinations associated with simple partial epileptic seizures, during which the patient remains conscious, may also be categorized by a patient unaware of his or her condition as ball lightning observation. Such visual hallucinations may occur as a result of an epileptic seizure in the occipital, temporo-occipital or temporal lobes of the cerebrum [1,2,3]. In some cases the hallucination is perceived as a coloured ball moving horizontally from the periphery to the centre of the vision. The ball may appear to be rotating or spinning. The colour of the ball can be red, yellow, blue or green. Sometimes, the ball may appear to have a solid structure surrounded by a thin glow or in other cases the ball appears to generate spark like phenomena. When the ball is moving towards the centre of the vision it may increase its intensity and when it reaches the centre it can 'explode' illuminating the whole field of vision. During the hallucinations the vision is obscured only in the area occupied by the apparent object. The hallucinations may last for 5 to 30 seconds and rarely up to a minute. Occipital seizures may spread into other regions of the brain giving auditory, olfactory and sensory sensations. These sensations could be buzzing sounds, the smell of burning rubber, pain with thermal perception especially in the arms and the face, and numbness and tingling sensation. In some cases a person may experience only one seizure during lifetime and may not be aware of the reason for the experience. Being of good health otherwise, the person may categorize the experience as a ball lightning encounter. If, as described above, the seizure spread into other regions of the brain the resulting experience may appear as electrical effects (the smell, heat sensation, tingling feeling etc.) of ball lightning. Epileptic seizures are a common and important medical problem, with about one in eleven persons experiencing at least one seizure at some point. Thus some of the ball lightning encounters presented in the literature could very well be associated with the experiences of persons who had an epileptic seizure with visual hallucinations. [1] Blom, S. et al., Epilepsy, Neurology, Edited by S-M Aquilonius and J. Fagius, Liber, 2000. [2] Panayiotopoulos, C. P., J. Neorl. Neurosurg. Psychiatry, 66, 536-540, 1999. [3] Bien et al, Brain,123, 244-253, 2000.

Cooray, G. K.; Cooray, V.

2007-12-01

283

Anticipating action effects recruits audiovisual movement representations in the ventral premotor cortex.  

PubMed

When table tennis players anticipate the course of the ball while preparing their motor responses, they not only observe their opponents striking the ball but also listen to events such as the sound of racket-ball contact. Because visual stimuli can be detected more easily when accompanied by a sound, we assumed that complementary sensory audiovisual information would influence the anticipation of biological motion, especially when the racket-ball contact is not presented visually, but has to be inferred from continuous movement kinematics and an abrupt sound. Twenty-six observers were examined with fMRI while watching point-light displays (PLDs) of an opposing table tennis player. Their task was to anticipate the resultant ball flight. The sound was presented complementary to the veracious event or at a deviant time point in its kinematics. Results showed that participants performed best in the complementary condition. Using a region-of-interest approach, fMRI data showed that complementary audiovisual stimulation elicited higher activation in the left temporo-occipital middle temporal gyrus (MTGto), the left primary motor cortex, and the right anterior intraparietal sulcus (aIPS). Both hemispheres also revealed higher activation in the ventral premotor cortex (vPMC) and the pars opercularis of the inferior frontal gyrus (BA 44). Ranking the behavioral effect of complementary versus conflicting audiovisual information over participants revealed an association between the complementary information and higher activation in the right vPMC. We conclude that the recruitment of movement representations in the auditory and visual modalities in the vPMC can be influenced by task-relevant cross-modal audiovisual interaction. PMID:25463138

Bischoff, Matthias; Zentgraf, Karen; Pilgramm, Sebastian; Stark, Rudolf; Krüger, Britta; Munzert, Jörn

2014-10-29

284

Training Transfers the Limits on Perception from Parietal to Ventral Cortex  

PubMed Central

Summary Visually guided behavior depends on (1) extracting and (2) discriminating signals from complex retinal inputs, and these perceptual skills improve with practice [1]. For instance, training on aerial reconnaissance facilitated World War II Allied military operations [2]; analysts pored over stereoscopic photographs, becoming expert at (1) segmenting pictures into meaningful items to break camouflage from (noisy) backgrounds, and (2) discriminating fine details to distinguish V-weapons from innocuous pylons. Training is understood to optimize neural circuits that process scene features (e.g., orientation) for particular purposes (e.g., judging position) [3–6]. Yet learning is most beneficial when it generalizes to other settings [7, 8] and is critical in recovery after adversity [9], challenging understanding of the circuitry involved. Here we used repetitive transcranial magnetic stimulation (rTMS) to infer the functional organization supporting learning generalization in the human brain. First, we show dissociable contributions of the posterior parietal cortex (PPC) versus lateral occipital (LO) circuits: extracting targets from noise is disrupted by PPC stimulation, in contrast to judging feature differences, which is affected by LO rTMS. Then, we demonstrate that training causes striking changes in this circuit: after feature training, identifying a target in noise is not disrupted by PPC stimulation but instead by LO stimulation. This indicates that training shifts the limits on perception from parietal to ventral brain regions and identifies a critical neural circuit for visual learning. We suggest that generalization is implemented by supplanting dynamic processing conducted in the PPC with specific feature templates stored in the ventral cortex. PMID:25283780

Chang, Dorita H.F.; Mevorach, Carmel; Kourtzi, Zoe; Welchman, Andrew E.

2014-01-01

285

The cerebral cortex of Albert Einstein: a description and preliminary analysis of unpublished photographs  

PubMed Central

Upon his death in 1955, Albert Einstein’s brain was removed, fixed and photographed from multiple angles. It was then sectioned into 240 blocks, and histological slides were prepared. At the time, a roadmap was drawn that illustrates the location within the brain of each block and its associated slides. Here we describe the external gross neuroanatomy of Einstein’s entire cerebral cortex from 14 recently discovered photographs, most of which were taken from unconventional angles. Two of the photographs reveal sulcal patterns of the medial surfaces of the hemispheres, and another shows the neuroanatomy of the right (exposed) insula. Most of Einstein’s sulci are identified, and sulcal patterns in various parts of the brain are compared with those of 85 human brains that have been described in the literature. To the extent currently possible, unusual features of Einstein’s brain are tentatively interpreted in light of what is known about the evolution of higher cognitive processes in humans. As an aid to future investigators, these (and other) features are correlated with blocks on the roadmap (and therefore histological slides). Einstein’s brain has an extraordinary prefrontal cortex, which may have contributed to the neurological substrates for some of his remarkable cognitive abilities. The primary somatosensory and motor cortices near the regions that typically represent face and tongue are greatly expanded in the left hemisphere. Einstein’s parietal lobes are also unusual and may have provided some of the neurological underpinnings for his visuospatial and mathematical skills, as others have hypothesized. Einstein’s brain has typical frontal and occipital shape asymmetries (petalias) and grossly asymmetrical inferior and superior parietal lobules. Contrary to the literature, Einstein’s brain is not spherical, does not lack parietal opercula and has non-confluent Sylvian and inferior postcentral sulci. PMID:23161163

Lepore, Frederick E.; Noe, Adrianne

2013-01-01

286

Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain  

PubMed Central

Background The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected. Results Using microarrays and quantitative PCR, the mRNA expression profiles of these two neuroanatomical regions were compared in postmortem brain tissue from RTT patients and normal controls. A subset of genes was differentially expressed in the frontal cortex of RTT brains, some of which are known to be associated with neurological disorders (clusterin and cytochrome c oxidase subunit 1) or are involved in synaptic vesicle cycling (dynamin 1). RNAi-mediated knockdown of MeCP2 in vitro, followed by further expression analysis demonstrated that the same direction of abnormal expression was recapitulated with MeCP2 knockdown, which for cytochrome c oxidase subunit 1 was associated with a functional respiratory chain defect. Chromatin immunoprecipitation (ChIP) analysis showed that MeCP2 associated with the promoter regions of some of these genes suggesting that loss of MeCP2 function may be responsible for their overexpression. Conclusions This study has shed more light on the subset of aberrantly expressed genes that result from MECP2 mutations. The mitochondrion has long been implicated in the pathogenesis of RTT, however it has not been at the forefront of RTT research interest since the discovery of MECP2 mutations. The functional consequence of the underexpression of cytochrome c oxidase subunit 1 indicates that this is an area that should be revisited. PMID:20420693

2010-01-01

287

Cerebral Cortex doi:10.1093/cercor/bhq210  

E-print Network

temporal lobe, MRI, prefrontal cortex, rhesus monkey Introduction Memory processing dependent on the prefrontal cortex (PFC) and medial temporal lobe is particularly susceptible to the effects of aging were acquired and volumes of the cerebrum, ventricles, prefrontal cortex (PFC), cal- carine cortex

288

The functions of the orbitofrontal cortex Edmund T. Rolls*  

E-print Network

- vocellular, lateral, part of the mediodorsal nucleus projects to the dorsolateral prefrontal cortex The prefrontal cortex is the cortex that receives pro- jections from the mediodorsal nucleus of the thalamus of the mediodorsal nucleus projects to the orbital (ventral) surface of the prefrontal cortex (which includes areas

Rolls, Edmund T.

289

Case History Study Anterior cingulate cortex and cognitive control: Neuropsychological  

E-print Network

between the dorsolateral, orbital and medial prefrontal cortex (MPFC). While the dorsolateral prefrontal and electrophysiological findings in two patients with lesions to dorsomedial prefrontal cortex M. Løvstad a, , I. Funderud: Accepted 25 July 2012 Available online 27 August 2012 Keywords: Anterior cingulate cortex Prefrontal cortex

Knight, Robert T.

290

Disruption of the dorsolateral prefrontal cortex facilitates the consolidation of procedural skills.  

PubMed

In explicit sequence learning tasks, an improvement in performance (skill) typically occurs after sleep-leading to the recent literature on sleep-dependent motor consolidation. Consolidation can also be facilitated during wakefulness if declarative knowledge for the sequence is reduced through a secondary cognitive task. Accordingly, declarative and procedural consolidation processes appear to mutually interact. Here we used TMS to test the hypothesis that functions in the dorsolateral prefrontal cortex (DLPFC) that support declarative memory formation indirectly reduce the formation of procedural representations. We hypothesize that disrupting the DLPFC immediately after sequence learning would degrade the retention or the consolidation of the sequence within the declarative memory system and thus facilitate consolidation within procedural memory systems, evident as wakeful off-line skill improvement. Inhibitory theta-burst TMS was applied to the left DLPFC (n = 10), to the right DLPFC (n = 10), or to an occipital cortical control site (n = 10) immediately after training on the serial reaction time task (SRTT). All groups were retested after eight daytime hours without sleep. TMS of either left or right DLPFC lead to skill improvements on the SRTT. Increase in skill was greater following right DLPFC stimulation than left DLPFC stimulation; there was no improvement in skill for the control group. Across all participants, free recall of the sequence was inversely related to the improvements in performance on the SRTT. These results support the hypothesis of interference between declarative and procedural consolidation processes and are discussed in the framework of the interactions between memory systems. PMID:19413472

Galea, Joseph M; Albert, Neil B; Ditye, Thomas; Miall, R Chris

2010-06-01

291

Integration of "what" and "where" in frontal cortex during visual imagery of scenes.  

PubMed

Imagination is a key function for many human activities, such as reminiscing, learning, or planning. Unravelling its neuro-biological basis is paramount to grasp the essence of our thoughts. Previous neuroimaging studies have identified brain regions subserving the visualisation of "what?" (e.g. faces or objects) and "where?" (e.g. spatial layout) content of mental images. However, the functional role of a common set of involved regions - the frontal regions - and their interplay with the "what" and "where" regions, has remained largely unspecified. This study combines functional MRI and electroencephalography to examine the full-brain network that underlies the visual imagery of complex scenes and to investigate the spectro-temporal properties of its nodes, especially of the frontal cortex. Our results indicate that frontal regions integrate the "what" and "where" content of our thoughts into one visually imagined scene. We link early synchronisation of anterior theta and beta oscillations to regional activation of right and central frontal cortices, reflecting retrieval and integration of information. These frontal regions orchestrate remote occipital-temporal regions (including calcarine sulcus and parahippocampal gyrus) that encode the detailed representations of the objects, and parietal "where" regions that encode the spatial layout into forming one coherent mental picture. Specifically the mesial superior frontal gyrus appears to have a principal integrative role, as its activity during the visualisation of the scene predicts subsequent performance on the imagery task. PMID:22186678

de Borst, Aline W; Sack, Alexander T; Jansma, Bernadette M; Esposito, Fabrizio; de Martino, Federico; Valente, Giancarlo; Roebroeck, Alard; di Salle, Francesco; Goebel, Rainer; Formisano, Elia

2012-03-01

292

Location, Location, Location: Alterations in the Functional Topography of Face- but not Object- or Place-Related Cortex in Adolescents with Autism  

PubMed Central

In autism, impairments in face processing are a relatively recent discovery, but have quickly become a widely accepted aspect of the behavioral profile. Only a handful of studies have investigated potential atypicalities in autism in the development of the neural substrates mediating face processing. High-functioning individuals with autism (HFA) and matched typically developing (TD) controls watched dynamic movie vignettes of faces, common objects, buildings, and scenes of navigation while undergoing an fMRI scan. With these data, we mapped the functional topography of category-selective activation for faces bilaterally in the fusiform gyrus, occipital face area, and posterior superior temporal sulcus. Additionally, we mapped category-selective activation for objects in the lateral occipital area and for places in the parahippocampal place area in the two groups. Our findings do not indicate a generalized disruption in the development of the entire ventral visual pathway in autism. Instead, our results suggest that the functional topography of face-related cortex is selectively disrupted in autism and that this alteration is present in early adolescence. Furthermore, for those HFA adolescents who do exhibit face-selective activation, this activation tends to be located in traditionally object-related regions, which supports the hypothesis that perceptual processing of faces in autism may be more akin to the perceptual processing of common objects in TD individuals. PMID:20631857

Scherf, K. Suzanne; Luna, Beatriz; Minshew, Nancy; Behrmann, Marlene

2009-01-01

293

Extrastriate cortex: A signature of perception grows.  

PubMed

Neuronal activity in area MT of the extrastriate visual cortex is correlated with the choices monkeys make on perceptual tasks. New evidence suggests that this correlation is stronger on some tasks than others. PMID:11566118

Britten, K H

2001-09-18

294

Somatosensory responses in a human motor cortex  

PubMed Central

Somatic sensory signals provide a major source of feedback to motor cortex. Changes in somatosensory systems after stroke or injury could profoundly influence brain computer interfaces (BCI) being developed to create new output signals from motor cortex activity patterns. We had the unique opportunity to study the responses of hand/arm area neurons in primary motor cortex to passive joint manipulation in a person with a long-standing brain stem stroke but intact sensory pathways. Neurons responded to passive manipulation of the contralateral shoulder, elbow, or wrist as predicted from prior studies of intact primates. Thus fundamental properties and organization were preserved despite arm/hand paralysis and damage to cortical outputs. The same neurons were engaged by attempted arm actions. These results indicate that intact sensory pathways retain the potential to influence primary motor cortex firing rates years after cortical outputs are interrupted and may contribute to online decoding of motor intentions for BCI applications. PMID:23343902

Donoghue, John P.; Hochberg, Leigh R.

2013-01-01

295

Effect of Visual Feedback on the Occipital-Parietal-Motor Network in Parkinson’s Disease with Freezing of Gait  

PubMed Central

Freezing of gait (FOG) is an elusive phenomenon that debilitates a large number of Parkinson’s disease (PD) patients regardless of stage of disease, medication status, or deep brain stimulation implantation. Sensory feedback cues, especially visual feedback cues, have been shown to alleviate FOG episodes or even prevent episodes from occurring. Here, we examine cortical information flow between occipital, parietal, and motor areas during the pre-movement stage of gait in a PD-with-FOG patient that had a strong positive behavioral response to visual cues, one PD-with-FOG patient without any behavioral response to visual cues, and age-matched healthy controls, before and after training with visual feedback. Results for this case study show differences in cortical information flow between the responding PD-with-FOG patient and the other two subject types, notably, an increased information flow in the beta range. Tentatively suggesting the formation of an alternative cortical sensory-motor pathway during training with visual feedback, these results are proposed as subject for further verification employing larger cohorts of patients. PMID:24409167

Velu, Priya D.; Mullen, Tim; Noh, Eunho; Valdivia, Matthew C.; Poizner, Howard; Baram, Yoram; de Sa, Virginia R.

2014-01-01

296

A layered network model of sensory cortex  

SciTech Connect

An integrated computational approach to modeling sensory systems which couples realistic layered neural models of sensory cortex and midbrain nuclei to detailed models of the sense organs (e.g., retina or cochlea) is described. The approach is applied to the auditory system. Through an exercise of the model, it is shown that spatial location of sounds may be a natural consequence of the way cochlear response is mapped onto the cortex. 31 refs., 23 figs., 3 tabs.

Travis, B.J.

1986-01-01

297

Food related processes in the insular cortex  

PubMed Central

The insular cortex is a multimodal brain region with regional cytoarchitectonic differences indicating various functional specializations. As a multisensory neural node, the insular cortex integrates perception, emotion, interoceptive awareness, cognition, and gustation. Regarding the latter, predominantly the anterior part of the insular cortex is regarded as the primary taste cortex. In this review, we will specifically focus on the involvement of the insula in food processing and on multimodal integration of food-related items. Influencing factors of insular activation elicited by various foods range from calorie-content to the internal physiologic state, body mass index or eating behavior. Sensory perception of food-related stimuli including seeing, smelling, and tasting elicits increased activation in the anterior and mid-dorsal part of the insular cortex. Apart from the pure sensory gustatory processing, there is also a strong association with the rewarding/hedonic aspects of food items, which is reflected in higher insular activity and stronger connections to other reward-related areas. Interestingly, the processing of food items has been found to elicit different insular activation in lean compared to obese subjects and in patients suffering from an eating disorder (anorexia nervosa (AN), bulimia nervosa (BN)). The knowledge of functional differences in the insular cortex opens up the opportunity for possible noninvasive treatment approaches for obesity and eating disorders. To target brain functions directly, real-time functional magnetic resonance imaging neurofeedback offers a state-of-the-art tool to learn to control the anterior insular cortex activity voluntarily. First evidence indicates that obese adults have an enhanced ability to regulate the anterior insular cortex. PMID:23986683

Frank, Sabine; Kullmann, Stephanie; Veit, Ralf

2013-01-01

298

Ultrasonographic percutaneous anatomy of the atlanto-occipital region and indirect ultrasound-guided cisternal puncture in the dog and the cat.  

PubMed

Cisternal puncture in dogs and cats is commonly carried out. This article describes the percutaneous ultrasound anatomy of the cisternal region in the dog and the cat and an indirect technique for ultrasound-guided cisternal puncture. Ultrasound images obtained ex vivo and in vivo were compared with anatomic sections and used to identify the landmarks for ultrasound-guided cisternal puncture. The ultrasound-guided procedure was established in cadavers and then applied in vivo in seven dogs and two cats. The anatomic landmarks for the ultrasound-guided puncture are the cisterna magna, the spinal cord, the two occipital condyles on transverse images, the external occipital crest and the dorsal arch of the first cervical vertebra on longitudinal images. Using these ultrasound anatomic landmarks, an indirect ultrasound-guided technique for cisternal puncture is applicable in the dog and the cat. PMID:24712312

Etienne, A-L; Audigié, F; Peeters, D; Gabriel, A; Busoni, V

2015-04-01

299

Intracranial spectral amplitude dynamics of perceptual suppression in fronto-insular, occipito-temporal, and primary visual cortex  

PubMed Central

If conscious perception requires global information integration across active distant brain networks, how does the loss of conscious perception affect neural processing in these distant networks? Pioneering studies on perceptual suppression (PS) described specific local neural network responses in primary visual cortex, thalamus and lateral prefrontal cortex of the macaque brain. Yet the neural effects of PS have rarely been studied with intracerebral recordings outside these cortices and simultaneously across distant brain areas. Here, we combined (1) a novel experimental paradigm in which we produced a similar perceptual disappearance and also re-appearance by using visual adaptation with transient contrast changes, with (2) electrophysiological observations from human intracranial electrodes sampling wide brain areas. We focused on broadband high-frequency (50–150 Hz, i.e., gamma) and low-frequency (8–24 Hz) neural activity amplitude modulations related to target visibility and invisibility. We report that low-frequency amplitude modulations reflected stimulus visibility in a larger ensemble of recording sites as compared to broadband gamma responses, across distinct brain regions including occipital, temporal and frontal cortices. Moreover, the dynamics of the broadband gamma response distinguished stimulus visibility from stimulus invisibility earlier in anterior insula and inferior frontal gyrus than in temporal regions, suggesting a possible role of fronto-insular cortices in top–down processing for conscious perception. Finally, we report that in primary visual cortex only low-frequency amplitude modulations correlated directly with perceptual status. Interestingly, in this sensory area broadband gamma was not modulated during PS but became positively modulated after 300 ms when stimuli were rendered visible again, suggesting that local networks could be ignited by top–down influences during conscious perception. PMID:25642199

Vidal, Juan R.; Perrone-Bertolotti, Marcela; Kahane, Philippe; Lachaux, Jean-Philippe

2015-01-01

300

Feedforward and feedback projections of caudal belt and parabelt areas of auditory cortex: refining the hierarchical model  

PubMed Central

Our working model of the primate auditory cortex recognizes three major regions (core, belt, parabelt), subdivided into thirteen areas. The connections between areas are topographically ordered in a manner consistent with information flow along two major anatomical axes: core-belt-parabelt and caudal-rostral. Remarkably, most of the connections supporting this model were revealed using retrograde tracing techniques. Little is known about laminar circuitry, as anterograde tracing of axon terminations has rarely been used. The purpose of the present study was to examine the laminar projections of three areas of auditory cortex, pursuant to analysis of all areas. The selected areas were: middle lateral belt (ML); caudomedial belt (CM); and caudal parabelt (CPB). Injections of anterograde tracers yielded data consistent with major features of our model, and also new findings that compel modifications. Results supporting the model were: (1) feedforward projection from ML and CM terminated in CPB; (2) feedforward projections from ML and CPB terminated in rostral areas of the belt and parabelt; and (3) feedback projections typified inputs to the core region from belt and parabelt. At odds with the model was the convergence of feedforward inputs into rostral medial belt from ML and CPB. This was unexpected since CPB is at a higher stage of the processing hierarchy, with mainly feedback projections to all other belt areas. Lastly, extending the model, feedforward projections from CM, ML, and CPB overlapped in the temporal parietal occipital area (TPO) in the superior temporal sulcus, indicating significant auditory influence on sensory processing in this region. The combined results refine our working model and highlight the need to complete studies of the laminar inputs to all areas of auditory cortex. Their documentation is essential for developing informed hypotheses about the neurophysiological influences of inputs to each layer and area. PMID:24795550

Hackett, Troy A.; de la Mothe, Lisa A.; Camalier, Corrie R.; Falchier, Arnaud; Lakatos, Peter; Kajikawa, Yoshinao; Schroeder, Charles E.

2014-01-01

301

Epilepsy surgery in the posterior cortex.  

PubMed

Fourteen (74%) of 19 patients obtained a significant reduction in seizures after posterior corticectomy; 6 (32%) were seizure-free over a median follow-up of 3.7 years (range, 1 to 14 years). Surgery included limited resections of the occipital lobe in 16 patients, posterior temporal region in 11, and posterior portion of parietal lobe in 7. Surgical failure related to probable multiple areas of epileptogenesis (4 patients), or limited resections (2 patients) to preserve visual fields (2 patients) and to avoid dyslexia (1 patient). Of 14 patients without a complete hemianopia preoperatively, 6 (43%) developed a new or increased visual field deficit, 2 (14%) of which were hemianopia. Four (36%) of 11 occipital lobe resections resulted in a new or increased visual field deficit: quadrantanopia in 3 and hemianopia in 1. Visual phenomena were the most common initial ictal symptoms, occurring in 13 (68%) of the 19 patients. Twelve patients had complex partial seizures: in 2, always without warning; in 7, always following an aura, usually visual; and in 3 patients, with or without warning. Scalp electroencephalography identified the origin of most recorded seizures in 12 (63%) of the 19 patients. A principal interictal spike focus appeared in 15 patients (79%), and always correlated with the epileptogenic lobe as defined by scalp and/or subdural-recorded seizures (14 patients) or by clinical analysis and computed tomography (1 patient). PMID:1892366

Blume, W T; Whiting, S E; Girvin, J P

1991-06-01

302

Temperature Instability of ReNu with MoistureLoc: A New Theory to Explain the Worldwide Fusarium Keratitis Epidemic of 2004–2006  

PubMed Central

Purpose A 2006 US Food and Drug Administration (FDA) inspection of Bausch & Lomb’s (B&L's) Greenville, South Carolina, manufacturing site indicated that B&L failed to regulate storage and transport temperatures of their products. The present study investigated the effect of storage temperature on the ability of contact lens solutions to inhibit growth of Fusarium species. Methods Six contact lens solutions were studied: ReNu with MoistureLoc (ReNu ML), ReNu MultiPlus, Complete Moistureplus, AQuify, Clear Care, and OPTI-FREE RepleniSH. Two bottles of each solution were separately stored at room temperature and 60°C for 4 weeks, serially diluted, then tested for their ability to inhibit growth of 11 Fusarium isolates (7 of which were associated with the keratitis epidemic). Results ReNu ML demonstrated the greatest decline in efficacy after 60°C storage. Clear Care and ReNu MultiPlus performed the best. Regarding the keratitis epidemic isolates only, the ReNu ML bottle stored at room temperature allowed growth in 27 of 84 combinations vs 67 of 84 combinations with the 60°C stored bottle. Conclusions When exposed to prolonged temperature elevation, ReNu ML loses its in vitro fungistatic activity to a much greater extent than other products. Improper temperature control of ReNu ML may have contributed to the Fusarium keratitis epidemic of 2004–2006. PMID:19277227

Bullock, John D.; Warwar, Ronald E.; Elder, B. Laurel; Northern, William I.

2008-01-01

303

Flood risk analysis and adaptive strategy in context of uncertainties: a case study of Nhieu Loc Thi Nghe Basin, Ho Chi Minh City  

NASA Astrophysics Data System (ADS)

The Nhieu Loc - Thi Nghe basin is the most important administrative and business area of Ho Chi Minh City. Due to system complexity of the basin such as the increasing trend of rainfall intensity, (tidal) water level and land subsidence, the simulation of hydrological, hydraulic variables for flooding prediction seems rather not adequate in practical projects. The basin is still highly vulnerable despite of multi-million USD investment for urban drainage improvement projects since the last decade. In this paper, an integrated system analysis in both spatial and temporal aspects based on statistical, GIS and modelling approaches has been conducted in order to: (1) Analyse risks before and after projects, (2) Foresee water-related risk under uncertainties of unfavourable driving factors and (3) Develop a sustainable flood risk management strategy for the basin. The results show that given the framework of risk analysis and adaptive strategy, certain urban developing plans in the basin must be carefully revised and/or checked in order to reduce the highly unexpected loss in the future

Ho, Long-Phi; Chau, Nguyen-Xuan-Quang; Nguyen, Hong-Quan

2013-04-01

304

Elastic instabilities in a layered cerebral cortex: A revised axonal tension model for cortex folding  

E-print Network

We model the elasticity of the cerebral cortex as a layered material with bending energy along the layers and elastic energy between them in both planar and polar geometries. The cortex is also subjected to axons pulling from the underlying white matter. Above a critical threshold force, a "flat" cortex configuration becomes unstable and periodic unduluations emerge, i.e. a buckling instability occurs. These undulations may indeed initiate folds in the cortex. We identify analytically the critical force and the critical wavelength of the undulations. Both quantities are physiologically relevant values. Our model is a revised version of the axonal tension model for cortex folding, with our version taking into account the layered structure of the cortex. Moreover, our model draws a connection with another competing model for cortex folding, namely the differential growth-induced buckling model. For the polar geometry, we study the relationship between brain size and the critical force and wavelength to understand why small mice brains exhibit no folds, while larger human brains do, for example. Finally, an estimate of the bending rigidity constant for the cortex can be made based on the critical wavelength.

O. V. Manyuhina; David Mayett; J. M. Schwarz

2014-12-04

305

Binding crossmodal object features in perirhinal cortex  

PubMed Central

Knowledge of objects in the world is stored in our brains as rich, multimodal representations. Because the neural pathways that process this diverse sensory information are largely anatomically distinct, a fundamental challenge to cognitive neuroscience is to explain how the brain binds the different sensory features that comprise an object to form meaningful, multimodal object representations. Studies with nonhuman primates suggest that a structure at the culmination of the object recognition system (the perirhinal cortex) performs this critical function. In contrast, human neuroimaging studies implicate the posterior superior temporal sulcus (pSTS). The results of the functional MRI study reported here resolve this apparent discrepancy by demonstrating that both pSTS and the perirhinal cortex contribute to crossmodal binding in humans, but in different ways. Significantly, only perirhinal cortex activity is modulated by meaning variables (e.g., semantic congruency and semantic category), suggesting that these two regions play complementary functional roles, with pSTS acting as a presemantic, heteromodal region for crossmodal perceptual features, and perirhinal cortex integrating these features into higher-level conceptual representations. This interpretation is supported by the results of our behavioral study: Patients with lesions, including the perirhinal cortex, but not patients with damage restricted to frontal cortex, were impaired on the same crossmodal integration task, and their performance was significantly influenced by the same semantic factors, mirroring the functional MRI findings. These results integrate nonhuman and human primate research by providing converging evidence that human perirhinal cortex is also critically involved in processing meaningful aspects of multimodal object representations. PMID:16702554

Taylor, Kirsten I.; Moss, Helen E.; Stamatakis, Emmanuel A.; Tyler, Lorraine K.

2006-01-01

306

Auditory connections and functions of prefrontal cortex  

PubMed Central

The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC). In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG) most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition. PMID:25100931

Plakke, Bethany; Romanski, Lizabeth M.

2014-01-01

307

Casagrande, V.A. and J.H. Kaas The afferent, intrinsic, and efferent of visual cortex primates. In: Cerebral Cortex, 10, Primary VisualCortex A. Peters  

E-print Network

Casagrande, V.A. and J.H. Kaas The afferent, intrinsic, and efferent of visual cortex primates. In-259. The Afferent, Intrinsic, and Efferent Connections of Primary Visual Cortex in Primates VIVIEN A, CASAGRANDE vi- sual cortex, area 17 or of primates, can be easily identified in most mammals (Kaas, 1987). (also

Casagrande, Vivien

308

Motor Cortex Neuroplasticity Following Brachial Plexus Transfer  

PubMed Central

In the past decade, research has demonstrated that cortical plasticity, once thought only to exist in the early stages of life, does indeed continue on into adulthood. Brain plasticity is now acknowledged as a core principle of brain function and describes the ability of the central nervous system to adapt and modify its structural organization and function as an adaptive response to functional demand. In this clinical case study we describe how we used neuroimaging techniques to observe the functional topographical expansion of a patch of cortex along the sensorimotor cortex of a 27-year-old woman following brachial plexus transfer surgery to re-innervate her left arm. We found bilateral activations present in the thalamus, caudate, insula as well as across the sensorimotor cortex during an elbow flex motor task. In contrast we found less activity in the sensorimotor cortex for a finger tap motor task in addition to activations lateralized to the left inferior frontal gyrus and thalamus and bilaterally for the insula. From a pain perspective the patient who had experienced extensive phantom limb pain (PLP) before surgery found these sensations were markedly reduced following transfer of the right brachial plexus to the intact left arm. Within the context of this clinical case the results suggest that functional improvements in limb mobility are associated with increased activation in the sensorimotor cortex as well as reduced PLP. PMID:23966938

Dimou, Stefan; Biggs, Michael; Tonkin, Michael; Hickie, Ian B.; Lagopoulos, Jim

2013-01-01

309

Auditory motion processing after early blindness  

PubMed Central

Studies showing that occipital cortex responds to auditory and tactile stimuli after early blindness are often interpreted as demonstrating that early blind subjects “see” auditory and tactile stimuli. However, it is not clear whether these occipital responses directly mediate the perception of auditory/tactile stimuli, or simply modulate or augment responses within other sensory areas. We used fMRI pattern classification to categorize the perceived direction of motion for both coherent and ambiguous auditory motion stimuli. In sighted individuals, perceived motion direction was accurately categorized based on neural responses within the planum temporale (PT) and right lateral occipital cortex (LOC). Within early blind individuals, auditory motion decisions for both stimuli were successfully categorized from responses within the human middle temporal complex (hMT+), but not the PT or right LOC. These findings suggest that early blind responses within hMT+ are associated with the perception of auditory motion, and that these responses in hMT+ may usurp some of the functions of nondeprived PT. Thus, our results provide further evidence that blind individuals do indeed “see” auditory motion. PMID:25378368

Jiang, Fang; Stecker, G. Christopher; Fine, Ione

2014-01-01

310

Insular cortex and neuropsychiatric disorders: a review of recent literature.  

PubMed

The insular cortex is located in the centre of the cerebral hemisphere, having connections with the primary and secondary somatosensory areas, anterior cingulate cortex, amygdaloid body, prefrontal cortex, superior temporal gyrus, temporal pole, orbitofrontal cortex, frontal and parietal opercula, primary and association auditory cortices, visual association cortex, olfactory bulb, hippocampus, entorhinal cortex, and motor cortex. Accordingly, dense connections exist among insular cortex neurons. The insular cortex is involved in the processing of visceral sensory, visceral motor, vestibular, attention, pain, emotion, verbal, motor information, inputs related to music and eating, in addition to gustatory, olfactory, visual, auditory, and tactile data. In this article, the literature on the relationship between the insular cortex and neuropsychiatric disorders was summarized following a computer search of the Pub-Med database. Recent neuroimaging data, including voxel based morphometry, PET and fMRI, revealed that the insular cortex was involved in various neuropsychiatric diseases such as mood disorders, panic disorders, PTSD, obsessive-compulsive disorders, eating disorders, and schizophrenia. Investigations of functions and connections of the insular cortex suggest that sensory information including gustatory, olfactory, visual, auditory, and tactile inputs converge on the insular cortex, and that these multimodal sensory information may be integrated there. PMID:17416488

Nagai, M; Kishi, K; Kato, S

2007-09-01

311

The Age of Human Cerebral Cortex Neurons  

SciTech Connect

The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J

2006-04-06

312

Nicotine and Synaptic Plasticity in Prefrontal Cortex  

NSDL National Science Digital Library

Nicotinic receptor activation enhances working memory and attention. The prefrontal cortex is a key brain area involved in working memory, and plasticity of excitatory synaptic transmission within the cortex is likely an important cellular mechanism of memory. A recent study has explored the cellular and synaptic basis of nicotine’s effects on excitability within the prefrontal cortex. The findings suggest that nicotine enhances inhibitory synaptic inputs to layer V pyramidal cells, which suppresses induction of long-term potentiation (LTP). This inhibitory effect can be overcome by stimulating the pyramidal cells in bursts, which suggests a modification in the signal-to-noise ratio for synaptic input. Thus, the impact of strong stimuli on working memory would be enhanced when combined with nicotinic receptor activity. These findings may lead to novel and more effective treatments for memory disorders.

Daniel S. McGehee (University of Chicago; Department of Anesthesia and Critical Care REV)

2007-08-14

313

Sexual differentiation of mammalian frontal cortex  

SciTech Connect

The pattern of distribution of the progesterone binding sites was examined in selected nuclei of the brain of male and female rat. In female rats the frontal cortex resulted to be the region with the highest concentration of /sup 3/H R5020 biding sites. However, in male rats the same region showed very little progestin binding activity. When female rats were androgenized via neonatal exposure to testosterone, the progestin binding activity of the frontal cortex became similar to that observed in male rats. The present investigation indicates that sexual differentiation of the rat brain may include also brain regions not clearly involved in sex related functions like the frontal cortex. 30 references, 2 figures, 1 table.

Maggi, A.; Zucchi, I.

1987-03-23

314

Spatial updating in human parietal cortex  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

315

The anterior cingulate cortex and pain processing  

PubMed Central

The neural network that contributes to the suffering which accompanies persistent pain states involves a number of brain regions. Of primary interest is the contribution of the cingulate cortex in processing the affective component of pain. The purpose of this review is to summarize recent data obtained using novel behavioral paradigms in animals based on measuring escape and/or avoidance of a noxious stimulus. These paradigms have successfully been used to study the nature of the neuroanatomical and neurochemical contributions of the anterior cingulate cortex (ACC) to higher order pain processing in rodents. PMID:24829554

Fuchs, Perry N.; Peng, Yuan Bo; Boyette-Davis, Jessica A.; Uhelski, Megan L.

2014-01-01

316

Keynote Address: Revaluing the Orbital Prefrontal Cortex  

PubMed Central

The importance of orbitofrontal cortex (OFC) in human behavioral regulation is no longer a matter of dispute, though its precise role remains a matter of ongoing investigation. It is ironic that this revaluation of OFC required a major departure from a historical nadir, during which it was viewed as redundant or “silent cortex,” a situation that prevailed even up to the latter half of the 20th century. The increasing wealth of data from diverse fields within neuroscience now provides an unambiguous testament to the importance of this cortical region in behavioral regulation and cognition in general. PMID:17846153

DOLAN, R. J.

2010-01-01

317

Encoding externally and internally accredited value in prefrontal cortex  

E-print Network

Smaller volume of prefrontal lobe in polysubstance abusers:prefrontal cortex: Anatomy, physiology, and neuropsychol- ogy of the frontal lobe.prefrontal cortex (PFC) occupies the front portion of the frontal lobe

Luk, Chung-Hay

2011-01-01

318

Growth and maintenance of the mouse adrenal cortex   

E-print Network

The adrenal cortex is classically divided into three morphologically and biochemically distinct zones, covered by a thin, cellular capsule. The adult adrenal cortex is a dynamic tissue in which distinct regions of cell ...

Chang, Su-Ping

2008-01-01

319

Neural substrates of visual spatial coding and visual feedback control for hand movements in allocentric and target-directed tasks.  

PubMed

Neuropsychological evidence suggests that different brain areas may be involved in movements that are directed at visual targets (e.g., pointing or reaching), and movements that are based on allocentric visual information (e.g., drawing or copying). Here we used fMRI to investigate the neural correlates of these two types of movements in healthy volunteers. Subjects (n?=?14) performed right hand movements in either a target-directed task (moving a cursor to a target dot) or an allocentric task (moving a cursor to reproduce the distance and direction between two distal target dots) with or without visual feedback about their hand movement. Movements were monitored with an MR compatible touch panel. A whole brain analysis revealed that movements in allocentric conditions led to an increase in activity in the fundus of the left intra-parietal sulcus (IPS), in posterior IPS, in bilateral dorsal premotor cortex (PMd), and in the lateral occipital complex (LOC). Visual feedback in both target-directed and allocentric conditions led to an increase in activity in area MT+, superior parietal-occipital cortex (SPOC), and posterior IPS (all bilateral). In addition, we found that visual feedback affected brain activity differently in target-directed as compared to allocentric conditions, particularly in the pre-supplementary motor area, PMd, IPS, and parieto-occipital cortex. Our results, in combination with previous findings, suggest that the LOC is essential for allocentric visual coding and that SPOC is involved in visual feedback control. The differences in brain activity between target-directed and allocentric visual feedback conditions may be related to behavioral differences in visual feedback control. Our results advance the understanding of the visual coordinate frame used by the LOC. In addition, because of the nature of the allocentric task, our results have relevance for the understanding of neural substrates of magnitude estimation and vector coding of movements. PMID:21941474

Thaler, Lore; Goodale, Melvyn A

2011-01-01

320

Neural Substrates of Visual Spatial Coding and Visual Feedback Control for Hand Movements in Allocentric and Target-Directed Tasks  

PubMed Central

Neuropsychological evidence suggests that different brain areas may be involved in movements that are directed at visual targets (e.g., pointing or reaching), and movements that are based on allocentric visual information (e.g., drawing or copying). Here we used fMRI to investigate the neural correlates of these two types of movements in healthy volunteers. Subjects (n?=?14) performed right hand movements in either a target-directed task (moving a cursor to a target dot) or an allocentric task (moving a cursor to reproduce the distance and direction between two distal target dots) with or without visual feedback about their hand movement. Movements were monitored with an MR compatible touch panel. A whole brain analysis revealed that movements in allocentric conditions led to an increase in activity in the fundus of the left intra-parietal sulcus (IPS), in posterior IPS, in bilateral dorsal premotor cortex (PMd), and in the lateral occipital complex (LOC). Visual feedback in both target-directed and allocentric conditions led to an increase in activity in area MT+, superior parietal–occipital cortex (SPOC), and posterior IPS (all bilateral). In addition, we found that visual feedback affected brain activity differently in target-directed as compared to allocentric conditions, particularly in the pre-supplementary motor area, PMd, IPS, and parieto-occipital cortex. Our results, in combination with previous findings, suggest that the LOC is essential for allocentric visual coding and that SPOC is involved in visual feedback control. The differences in brain activity between target-directed and allocentric visual feedback conditions may be related to behavioral differences in visual feedback control. Our results advance the understanding of the visual coordinate frame used by the LOC. In addition, because of the nature of the allocentric task, our results have relevance for the understanding of neural substrates of magnitude estimation and vector coding of movements. PMID:21941474

Thaler, Lore; Goodale, Melvyn A.

2011-01-01

321

Structure and plasticity potential of neural networks in the cerebral cortex  

NASA Astrophysics Data System (ADS)

In this thesis, we first described a theoretical framework for the analysis of spine remodeling plasticity. We provided a quantitative description of two models of spine remodeling in which the presence of a bouton is either required or not for the formation of a new synapse. We derived expressions for the density of potential synapses in the neuropil, the connectivity fraction, which is the ratio of actual to potential synapses, and the number of structurally different circuits attainable with spine remodeling. We calculated these parameters in mouse occipital cortex, rat CA1, monkey V1, and human temporal cortex. We found that on average a dendritic spine can choose among 4-7 potential targets in rodents and 10-20 potential targets in primates. The neuropil's potential for structural circuit remodeling is highest in rat CA1 (7.1-8.6 bits/mum3) and lowest in monkey V1 (1.3-1.5 bits/mum 3 We next studied the role neuron morphology plays in defining synaptic connectivity. As previously stated it is clear that only pairs of neurons with closely positioned axonal and dendritic branches can be synaptically coupled. For excitatory neurons in the cerebral cortex, ). We also evaluated the lower bound of neuron selectivity in the choice of synaptic partners. Post-synaptic excitatory neurons in rodents make synaptic contacts with more than 21-30% of pre-synaptic axons encountered with new spine growth. Primate neurons appear to be more selective, making synaptic connections with more than 7-15% of encountered axons. We next studied the role neuron morphology plays in defining synaptic connectivity. As previously stated it is clear that only pairs of neurons with closely positioned axonal and dendritic branches can be synaptically coupled. For excitatory neurons in the cerebral cortex, such axo-dendritic oppositions, or potential synapses, must be bridged by dendritic spines to form synaptic connections. To explore the rules by which synaptic connections are formed within the constraints imposed by neuron morphology, we compared the distributions of the numbers of actual and potential synapses between pre- and post-synaptic neurons forming different laminar projections in rat barrel cortex. Quantitative comparison explicitly ruled out the hypothesis that individual synapses between neurons are formed independently of each other. Instead, the data are consistent with a cooperative scheme of synapse formation, where multiple-synaptic connections between neurons are stabilized, while neurons that do not establish a critical number of synapses are not likely to remain synaptically coupled. In the above two projects, analysis of potential synapse numbers played an important role in shaping our understanding of connectivity and structural plasticity. In the third part of this thesis, we shift our attention to the study of the distribution of potential synapse numbers. This distribution is dependent on the details of neuron morphology and it defines synaptic connectivity patterns attainable with spine remodeling. To better understand how the distribution of potential synapse numbers is influenced by the overlap and the shapes of axonal and dendritic arbors, we first analyzed uniform disconnected arbors generated in silico. The resulting distributions are well described by binomial functions. We used a dataset of neurons reconstructed in 3D and generated the potential synapse distributions for neurons of different classes. Quantitative analysis showed that the binomial distribution is a good fit to this data as well. All distributions considered clustered into two categories, inhibitory to inhibitory and excitatory to excitatory projections. We showed that the distributions of potential synapse numbers are universally described by a family of single parameter (p) binomial functions, where p = 0.08, and for the inhibitory and p = 0.19 for the excitatory projections. In the last part of this thesis an attempt is made to incorporate some of the biological constraints we considered thus far, into an artificial neural network model. It became

Fares, Tarec Edmond

322

Anatomo-functional study of the temporo-parieto-occipital region: dissection, tractographic and brain mapping evidence from a neurosurgical perspective.  

PubMed

The temporo-parieto-occipital (TPO) junction is a complex brain territory heavily involved in several high-level neurological functions, such as language, visuo-spatial recognition, writing, reading, symbol processing, calculation, self-processing, working memory, musical memory, and face and object recognition. Recent studies indicate that this area is covered by a thick network of white matter (WM) connections, which provide efficient and multimodal integration of information between both local and distant cortical nodes. It is important for neurosurgeons to have good knowledge of the three-dimensional subcortical organisation of this highly connected region to minimise post-operative permanent deficits. The aim of this dissection study was to highlight the subcortical functional anatomy from a topographical surgical perspective. Eight human hemispheres (four left, four right) obtained from four human cadavers were dissected according to Klingler's technique. Proceeding latero-medially, the authors describe the anatomical courses of and the relationships between the main pathways crossing the TPO. The results obtained from dissection were first integrated with diffusion tensor imaging reconstructions and subsequently with functional data obtained from three surgical cases, all resection of infiltrating glial tumours using direct electrical mapping in awake patients. The subcortical limits for performing safe lesionectomies within the TPO region are as follows: within the parietal region, the anterior horizontal part of the superior longitudinal fasciculus and, more deeply, the arcuate fasciculus; dorsally, the vertical projective thalamo-cortical fibres. For lesions located within the temporal and occipital lobes, the resection should be tailored according to the orientation of the horizontal associative pathways (the inferior fronto-occipital fascicle, inferior longitudinal fascicle and optic radiation). The relationships between the WM tracts and the ventricle system were also examined. These results indicate that a detailed anatomo-functional awareness of the WM architecture within the TPO area is mandatory when approaching intrinsic brain lesions to optimise surgical results and to minimise post-operative morbidity. PMID:24975421

De Benedictis, Alessandro; Duffau, Hugues; Paradiso, Beatrice; Grandi, Enrico; Balbi, Sergio; Granieri, Enrico; Colarusso, Enzo; Chioffi, Franco; Marras, Carlo Efisio; Sarubbo, Silvio

2014-08-01

323

A Survey on ARM Cortex A Overview of ARM Processors  

E-print Network

1 A Survey on ARM Cortex A Processors Wei Wang Tanima Dey #12;2 Overview of ARM Processors Focusing on Cortex A9 & Cortex A15 ARM ships no processors but only IP cores For SoC integration RCT etc. #12;10 ARM Instruction Set Architecture · ARM processor architecture supports 32-bit ARM

Skadron, Kevin

324

Receptive Fields in Human Visual Cortex Mapped with Surface Electrodes  

E-print Network

the presence of multiple retinotopically organized visual areas in the human brain that appear to be homologous) organization in human visual cortex. This is particularly true in later stages of visual cortex, where largeReceptive Fields in Human Visual Cortex Mapped with Surface Electrodes Daniel Yoshor1 , William H

Ghose, Geoff

325

Research Report Involvement of right dorsolateral prefrontal cortex in  

E-print Network

Research Report Involvement of right dorsolateral prefrontal cortex in ill-structured design, the design task was associated with greater activity in right dorsolateral prefrontal cortex compared evidence on the role of right dorsolateral prefrontal cortex in ill-structured situations, such as those

326

Prefrontal Cortex Function in Nonpsychotic Siblings of Individuals with Schizophrenia  

E-print Network

of the dorsolateral prefrontal cortex (DLPFC) (4). The results of several studies in individuals with schizophreniaPrefrontal Cortex Function in Nonpsychotic Siblings of Individuals with Schizophrenia Zainab prefrontal cortex (DLPFC). Methods: We used a variation of the continuous performance task, the AX

327

Behavioral/Systems/Cognitive Dorsolateral Prefrontal Cortex Drives Mesolimbic  

E-print Network

Behavioral/Systems/Cognitive Dorsolateral Prefrontal Cortex Drives Mesolimbic Dopaminergic Regions behavior (for review, see Goto and Grace, 2005). The PFC, spe- cifically the dorsolateral prefrontal cortex tegmental area (VTA) to the nucleus accumbens (NAcc) and the prefrontal cortex (PFC) (Berridge and Robinson

Adcock, R. Alison

328

ORIGINAL ARTICLES Working Memory and Prefrontal Cortex Dysfunction  

E-print Network

significant group differences in the activation of dorsolateral prefrontal cortex associated with working activation of right dorsolateral prefrontal cortex in re- sponse to working memory tasks demands, whereas those with major depression showed clear activation of right and left dorsolateral prefrontal cortex

Steinbach, Joe Henry

329

Sound frequency representation in cat auditory cortex  

Microsoft Academic Search

Using the intrinsic signal optical recording technique, we reconstructed the two-dimensional pattern of stimulus-evoked neuronal activities in the auditory cortex of anesthetized and paralyzed cats. The average magnitude of intrinsic signal in response to a pure tone stimulus increased steadily as the sound pressure level increased. A detailed analysis demonstrated that the evoked signals at early frames were scaled by

Vassiliy Tsytsarev; Tadashi Yamazaki; Jérôme Ribot; Shigeru Tanaka

2004-01-01

330

INTENTIONAL MAPS IN POSTERIOR PARIETAL CORTEX  

Microsoft Academic Search

? Abstract The posterior parietal cortex (PPC), historically believed to be a sensory structure, is now viewed as an area important for sensory-motor integration. Among its functions is the forming of intentions, that is, high-level cognitive plans for movement. There is a map of intentions within the PPC, with different subregions dedicated to the planning of eye movements, reaching movements,

Richard A. Andersen; Christopher A. Buneo

2002-01-01

331

Excitatory neuronal connectivity in the barrel cortex  

PubMed Central

Neocortical areas are believed to be organized into vertical modules, the cortical columns, and the horizontal layers 1–6. In the somatosensory barrel cortex these columns are defined by the readily discernible barrel structure in layer 4. Information processing in the neocortex occurs along vertical and horizontal axes, thereby linking individual barrel-related columns via axons running through the different cortical layers of the barrel cortex. Long-range signaling occurs within the neocortical layers but also through axons projecting through the white matter to other neocortical areas and subcortical brain regions. Because of the ease of identification of barrel-related columns, the rodent barrel cortex has become a prototypical system to study the interactions between different neuronal connections within a sensory cortical area and between this area and other cortical as well subcortical regions. Such interactions will be discussed specifically for the feed-forward and feedback loops between the somatosensory and the somatomotor cortices as well as the different thalamic nuclei. In addition, recent advances concerning the morphological characteristics of excitatory neurons and their impact on the synaptic connectivity patterns and signaling properties of neuronal microcircuits in the whisker-related somatosensory cortex will be reviewed. In this context, their relationship between the structural properties of barrel-related columns and their function as a module in vertical synaptic signaling in the whisker-related cortical areas will be discussed. PMID:22798946

Feldmeyer, Dirk

2012-01-01

332

The insular cortex: a comparative perspective.  

PubMed

The human insular cortex is involved in a variety of viscerosensory, visceromotor, and interoceptive functions, and plays a role in complex processes such as emotions, music, and language. Across mammals, the insula has considerable morphologic variability. We review the structure and connectivity of the insula in laboratory animals (mouse, domestic cat, macaque monkey), and we present original data on the morphology and cytoarchitecture of insular cortex in less common species including a large carnivore (the Atlantic walrus, Odobenus rosmarus), two artiodactyls (the pigmy hippopotamus, Hexaprotodon liberiensis, and the Western bongo, Tragelaphus eurycerus), two cetaceans (the beluga whale, Delphinapterus leucas, and the minke whale, Balaenoptera acutorostrata), and a sirenian (the Florida manatee, Trichechus manatus latirostris). The insula shows substantial variability in shape, extent, and gyral and sulcal patterns, as well as differences in laminar organization, cellular specialization, and structural association with the claustrum. Our observations reveal that the insular cortex is extremely variable among mammals. These differences could be related to the role exerted by specific and selective pressures on cortical structure during evolution. We conclude that it is not possible to identify a general model of organization for the mammalian insular cortex. PMID:20512368

Butti, Camilla; Hof, Patrick R

2010-06-01

333

Motor Cortex Reorganization across the Lifespan  

ERIC Educational Resources Information Center

The brain is a highly dynamic structure with the capacity for profound structural and functional change. Such neural plasticity has been well characterized within motor cortex and is believed to represent one of the neural mechanisms for acquiring and modifying motor behaviors. A number of behavioral and neural signals have been identified that…

Plowman, Emily K.; Kleim, Jeffrey A.

2010-01-01

334

Speech offsets activate the right parietal cortex.  

PubMed

Speech offsets, i.e., sudden transitions from continuous speech sound to silence, activated both hemispheres differently. In addition to peak activities in the bilateral temporal cortices at about 120 ms after the offsets, the right parietal cortex was activated later irrespective of the stimulated ear. The result was discussed in the context of auditory attention. PMID:15350281

Hamada, Takashi; Iwaki, Sunao; Kawano, Tsuneo

2004-09-01

335

The chronoarchitecture of the cerebral cortex  

Microsoft Academic Search

We review here a new approach to mapping the human cerebral cortex into distinct subdivisions. Unlike cytoarchitecture or traditional functional imaging, it does not rely on specific anatomical markers or functional hypotheses. Instead, we propose that the unique activity time course (ATC) of each cortical subdivision, elicited during natural conditions, acts as a temporal fingerprint that can be used to

Andreas Bartels; Semir Zeki

2005-01-01

336

Developmental Outcomes after Early Prefrontal Cortex Damage  

ERIC Educational Resources Information Center

The neuropsychological bases of cognitive, social, and moral development are minimally understood, with a seemingly wide chasm between developmental theories and brain maturation models. As one approach to bridging ideas in these areas, we review 10 cases of early prefrontal cortex damage from the clinical literature, highlighting overall clinical…

Eslinger, Paul J.; Flaherty-Craig, Claire V.; Benton, Arthur L.

2004-01-01

337

Neurophotonics applications to motor cortex research  

PubMed Central

Neurophotonics methods offer powerful ways to access neuronal signals and circuits. We highlight recent advances and current themes in this area, emphasizing tools for mapping, monitoring, and manipulating excitatory projection neurons and their synaptic circuits in mouse motor cortex. PMID:25553337

Suter, Benjamin A.; Yamawaki, Naoki; Borges, Katharine; Li, Xiaojian; Kiritani, Taro; Hooks, Bryan M.; Shepherd, Gordon M. G.

2014-01-01

338

The harmonic organization of auditory cortex  

PubMed Central

A fundamental structure of sounds encountered in the natural environment is the harmonicity. Harmonicity is an essential component of music found in all cultures. It is also a unique feature of vocal communication sounds such as human speech and animal vocalizations. Harmonics in sounds are produced by a variety of acoustic generators and reflectors in the natural environment, including vocal apparatuses of humans and animal species as well as music instruments of many types. We live in an acoustic world full of harmonicity. Given the widespread existence of the harmonicity in many aspects of the hearing environment, it is natural to expect that it be reflected in the evolution and development of the auditory systems of both humans and animals, in particular the auditory cortex. Recent neuroimaging and neurophysiology experiments have identified regions of non-primary auditory cortex in humans and non-human primates that have selective responses to harmonic pitches. Accumulating evidence has also shown that neurons in many regions of the auditory cortex exhibit characteristic responses to harmonically related frequencies beyond the range of pitch. Together, these findings suggest that a fundamental organizational principle of auditory cortex is based on the harmonicity. Such an organization likely plays an important role in music processing by the brain. It may also form the basis of the preference for particular classes of music and voice sounds. PMID:24381544

Wang, Xiaoqin

2013-01-01

339

The Piriform Cortex and Human Focal Epilepsy  

PubMed Central

It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic – being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in human beings. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review, we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology, and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability. PMID:25538678

Vaughan, David N.; Jackson, Graeme D.

2014-01-01

340

Cholecystokinin from the entorhinal cortex enables neural plasticity in the auditory cortex  

PubMed Central

Patients with damage to the medial temporal lobe show deficits in forming new declarative memories but can still recall older memories, suggesting that the medial temporal lobe is necessary for encoding memories in the neocortex. Here, we found that cortical projection neurons in the perirhinal and entorhinal cortices were mostly immunopositive for cholecystokinin (CCK). Local infusion of CCK in the auditory cortex of anesthetized rats induced plastic changes that enabled cortical neurons to potentiate their responses or to start responding to an auditory stimulus that was paired with a tone that robustly triggered action potentials. CCK infusion also enabled auditory neurons to start responding to a light stimulus that was paired with a noise burst. In vivo intracellular recordings in the auditory cortex showed that synaptic strength was potentiated after two pairings of presynaptic and postsynaptic activity in the presence of CCK. Infusion of a CCKB antagonist in the auditory cortex prevented the formation of a visuo-auditory association in awake rats. Finally, activation of the entorhinal cortex potentiated neuronal responses in the auditory cortex, which was suppressed by infusion of a CCKB antagonist. Together, these findings suggest that the medial temporal lobe influences neocortical plasticity via CCK-positive cortical projection neurons in the entorhinal cortex. PMID:24343575

Li, Xiao; Yu, Kai; Zhang, Zicong; Sun, Wenjian; Yang, Zhou; Feng, Jingyu; Chen, Xi; Liu, Chun-Hua; Wang, Haitao; Guo, Yi Ping; He, Jufang

2014-01-01

341

The role of prefrontal cortex and posterior parietal cortex in task switching  

PubMed Central

Human ability to switch from one cognitive task to another involves both endogenous preparation without an external stimulus and exogenous adjustment in response to the external stimulus. In an event-related functional MRI study, participants performed pairs of two tasks that are either the same (task repetition) or different (task switch) from each other. On half of the trials, foreknowledge about task repetition or task switch was available. On the other half, it was not. Endogenous preparation seems to involve lateral prefrontal cortex (BA 46/45) and posterior parietal cortex (BA 40). During preparation, higher activation increases in inferior lateral prefrontal cortex and superior posterior parietal cortex were associated with foreknowledge than with no foreknowledge. Exogenous adjustment seems to involve superior prefrontal cortex (BA 8) and posterior parietal cortex (BA 39/40) in general. During a task switch with no foreknowledge, activations in these areas were relatively higher than during a task repetition with no foreknowledge. These results suggest that endogenous preparation and exogenous adjustment for a task switch may be independent processes involving different brain areas. PMID:11069306

Sohn, Myeong-Ho; Ursu, Stefan; Anderson, John R.; Stenger, V. Andrew; Carter, Cameron S.

2000-01-01

342

Cerebral cortex structure in prodromal Huntington disease.  

PubMed

Neuroimaging studies of subjects who are gene-expanded for Huntington Disease, but not yet diagnosed (termed prodromal HD), report that the cortex is "spared," despite the decrement in striatal and cerebral white-matter volume. Measurement of whole-cortex volume can mask more subtle, but potentially clinically relevant regional changes in volume, thinning, or surface area. The current study addressed this limitation by evaluating cortical morphology of 523 prodromal HD subjects. Participants included 693 individuals enrolled in the PREDICT-HD protocol. Of these participants, 523 carried the HD gene mutation (prodromal HD group); the remaining 170 were non gene-expanded and served as the comparison group. Based on age and CAG repeat length, gene-expanded subjects were categorized as "Far from onset," "Midway to onset," "Near onset," and "already diagnosed." MRI scans were processed using FreeSurfer. Cortical volume, thickness, and surface area were not significantly different between the Far from onset group and controls. However, beginning in the Midway to onset group, the cortex showed significant volume decrement, affecting most the posterior and superior cerebral regions. This pattern progressed when evaluating the groups further into the disease process. Areas that remained mostly unaffected included ventral and medial regions of the frontal and temporal cortex. Morphologic changes were mostly in thinning as surface area did not substantially change in most regions. Early in the course of HD, the cortex shows changes that are manifest as cortical thinning and are most robust in the posterior and superior regions of the cerebrum. PMID:20688164

Nopoulos, Peggy C; Aylward, Elizabeth H; Ross, Christopher A; Johnson, Hans J; Magnotta, Vincent A; Juhl, Andrew R; Pierson, Ronald K; Mills, James; Langbehn, Douglas R; Paulsen, Jane S

2010-12-01

343

Cerebral Cortex Structure in Prodromal Huntington Disease  

PubMed Central

Neuroimaging studies of subjects who are gene-expanded for Huntington Disease, but not yet diagnosed (termed prodromal HD), report that the cortex is “spared,” despite the decrement in striatal and cerebral white-matter volume. Measurement of whole-cortex volume can mask more subtle, but potentially clinically relevant regional changes in volume, thinning, or surface area. The current study addressed this limitation by evaluating cortical morphology of 523 prodromal HD subjects. Participants included 693 individuals enrolled in the PREDICT-HD protocol. Of these participants, 523 carried the HD gene mutation (prodromal HD group); the remaining 170 were non gene-expanded and served as the comparison group. Based on age and CAG repeat length, gene-expanded subjects were categorized as “Far from onset,” “Midway to onset,” “Near onset,” and “already diagnosed.” MRI scans were processed using FreeSurfer. Cortical volume, thickness, and surface area were not significantly different between the Far from onset group and controls. However, beginning in the Midway to onset group, the cortex showed significant volume decrement, affecting most the posterior and superior cerebral regions. This pattern progressed when evaluating the groups further into the disease process. Areas that remained mostly unaffected included ventral and medial regions of the frontal and temporal cortex. Morphologic changes were mostly in thinning as surface area did not substantially change in most regions. Early in the course of HD, the cortex shows changes that are manifest as cortical thinning and are most robust in the posterior and superior regions of the cerebrum. PMID:20688164

Nopoulos, Peggy C.; Aylward, Elizabeth H.; Ross, Christopher A.; Johnson, Hans J.; Magnotta, Vincent A.; Juhl, Andrew R.; Pierson, Ronald K.; Mills, James; Langbehn, Douglas R.; Paulsen, Jane S.

2010-01-01

344

Research report Necrosis, apoptosis and hybrid death in the cortex and thalamus after barrel cortex ischemia in rats  

Microsoft Academic Search

Focal ischemia in the cerebral cortex results in acute and delayed cell death in the ischemic cortex and non-ischemic thalamus. We examined the hypothesis that neurons in ischemic and non-ischemic regions died from different mechanisms; specifically, we tested whether a mixed form of cell death containing both necrotic and apoptotic changes could be identified in individual cells. Focal barrel cortex

Ling Wei; Da-Jun Ying; Lin Cui; Jennifer Langsdorf; Shan Ping Yu

345

Reduced visual cortex gray matter volume and thickness in young adults who witnessed domestic violence during childhood.  

PubMed

Exposure to interparental violence is associated with negative outcomes, such as depression, post-traumatic stress disorder and reduced cognitive abilities. However, little is known about the potential effects of witnessing domestic violence during childhood on gray matter volume (GMV) or cortical thickness. High-resolution 3.0 T volumetric scans (Siemens Trio Scanner) were obtained on 52 subjects (18-25 years) including 22 (6 males/16 females) with a history of visually witnessing episodes of domestic violence, and 30 (8 males/22 females) unexposed control subjects, with neither a current nor past DSM-IV Axis I or II disorder. Potential confounding effects of age, gender, level of parental verbal aggression, parental education, financial stress, full scale IQ, and total GMV, or average thickness were modeled using voxel based morphometry and FreeSurfer. Witnessing domestic violence subjects had a 6.1% GMV reduction in the right lingual gyrus (BA18) (P?=?0.029, False Discovery Rate corrected peak level). Thickness in this region was also reduced, as was thickness in V2 bilaterally and left occipital pole. Theses regions were maximally sensitive to exposure to witnessing domestic violence between 11-13 years of age. Regional reductions in GMV and thickness were observed in both susceptible and resilient witnessing domestic violence subjects. Results in subjects witnessing domestic violence were similar to previously reported results in subjects with childhood sexual abuse, as the primary region affected was visual cortex. Brain regions that process and convey the adverse sensory input of the abuse may be specifically modified by this experience, particularly in subjects exposed to a single type of maltreatment. Exposure to multiple types of maltreatment is more commonly associated with morphological alterations in corticolimbic regions. These findings fit with preclinical studies showing that visual cortex is a highly plastic structure. PMID:23300699

Tomoda, Akemi; Polcari, Ann; Anderson, Carl M; Teicher, Martin H

2012-01-01

346

Patterns of neural activity in the human ventral premotor cortex reflect a whole-body multisensory percept.  

PubMed

Previous research has shown that the integration of multisensory signals from the body in fronto-parietal association areas underlies the perception of a body part as belonging to one's physical self. What are the neural mechanisms that enable the perception of one's entire body as a unified entity? In one behavioral and one fMRI multivoxel pattern analysis experiment, we used a full-body illusion to investigate how congruent visuo-tactile signals from a single body part facilitate the emergence of the sense of ownership of the entire body. To elicit this illusion, participants viewed the body of a mannequin from the first-person perspective via head-mounted displays while synchronous touches were applied to the hand, abdomen, or leg of the bodies of the participant and the mannequin; asynchronous visuo-tactile stimuli served as controls. The psychometric data indicated that the participants perceived ownership of the entire artificial body regardless of the body segment that received the synchronous visuo-tactile stimuli. Based on multivoxel pattern analysis, we found that the neural responses in the left ventral premotor cortex displayed illusion-specific activity patterns that generalized across all tested pairs of body parts. Crucially, a tripartite generalization analysis revealed the whole-body specificity of these premotor activity patterns. Finally, we also identified multivoxel patterns in the premotor, intraparietal, and lateral occipital cortices and in the putamen that reflected multisensory responses specific to individual body parts. Based on these results, we propose that the dynamic formation of a whole-body percept may be mediated by neuronal populations in the ventral premotor cortex that contain visuo-tactile receptive fields encompassing multiple body segments. PMID:25583608

Gentile, Giovanni; Björnsdotter, Malin; Petkova, Valeria I; Abdulkarim, Zakaryah; Ehrsson, H Henrik

2015-04-01

347

Patterns of neural activity in the human ventral premotor cortex reflect a whole-body multisensory percept  

PubMed Central

Previous research has shown that the integration of multisensory signals from the body in fronto-parietal association areas underlies the perception of a body part as belonging to one's physical self. What are the neural mechanisms that enable the perception of one's entire body as a unified entity? In one behavioral and one fMRI multivoxel pattern analysis experiment, we used a full-body illusion to investigate how congruent visuo-tactile signals from a single body part facilitate the emergence of the sense of ownership of the entire body. To elicit this illusion, participants viewed the body of a mannequin from the first-person perspective via head-mounted displays while synchronous touches were applied to the hand, abdomen, or leg of the bodies of the participant and the mannequin; asynchronous visuo-tactile stimuli served as controls. The psychometric data indicated that the participants perceived ownership of the entire artificial body regardless of the body segment that received the synchronous visuo-tactile stimuli. Based on multivoxel pattern analysis, we found that the neural responses in the left ventral premotor cortex displayed illusion-specific activity patterns that generalized across all tested pairs of body parts. Crucially, a tripartite generalization analysis revealed the whole-body specificity of these premotor activity patterns. Finally, we also identified multivoxel patterns in the premotor, intraparietal, and lateral occipital cortices and in the putamen that reflected multisensory responses specific to individual body parts. Based on these results, we propose that the dynamic formation of a whole-body percept may be mediated by neuronal populations in the ventral premotor cortex that contain visuo-tactile receptive fields encompassing multiple body segments. PMID:25583608

Gentile, Giovanni; Björnsdotter, Malin; Petkova, Valeria I.; Abdulkarim, Zakaryah; Ehrsson, H. Henrik

2015-01-01

348

Reduced Visual Cortex Gray Matter Volume and Thickness in Young Adults Who Witnessed Domestic Violence during Childhood  

PubMed Central

Exposure to interparental violence is associated with negative outcomes, such as depression, post-traumatic stress disorder and reduced cognitive abilities. However, little is known about the potential effects of witnessing domestic violence during childhood on gray matter volume (GMV) or cortical thickness. High-resolution 3.0 T volumetric scans (Siemens Trio Scanner) were obtained on 52 subjects (18–25 years) including 22 (6 males/16 females) with a history of visually witnessing episodes of domestic violence, and 30 (8 males/22 females) unexposed control subjects, with neither a current nor past DSM-IV Axis I or II disorder. Potential confounding effects of age, gender, level of parental verbal aggression, parental education, financial stress, full scale IQ, and total GMV, or average thickness were modeled using voxel based morphometry and FreeSurfer. Witnessing domestic violence subjects had a 6.1% GMV reduction in the right lingual gyrus (BA18) (P?=?0.029, False Discovery Rate corrected peak level). Thickness in this region was also reduced, as was thickness in V2 bilaterally and left occipital pole. Theses regions were maximally sensitive to exposure to witnessing domestic violence between 11–13 years of age. Regional reductions in GMV and thickness were observed in both susceptible and resilient witnessing domestic violence subjects. Results in subjects witnessing domestic violence were similar to previously reported results in subjects with childhood sexual abuse, as the primary region affected was visual cortex. Brain regions that process and convey the adverse sensory input of the abuse may be specifically modified by this experience, particularly in subjects exposed to a single type of maltreatment. Exposure to multiple types of maltreatment is more commonly associated with morphological alterations in corticolimbic regions. These findings fit with preclinical studies showing that visual cortex is a highly plastic structure. PMID:23300699

Tomoda, Akemi; Polcari, Ann; Anderson, Carl M.; Teicher, Martin H.

2012-01-01

349

fMRI analysis of contrast polarity in face-selective cortex in humans and monkeys.  

PubMed

Recognition is strongly impaired when the normal contrast polarity of faces is reversed. For instance, otherwise-familiar faces become very difficult to recognize when viewed as photographic negatives. Here, we used fMRI to demonstrate related properties in visual cortex: 1) fMRI responses in the human Fusiform Face Area (FFA) decreased strongly (26%) to contrast-reversed faces across a wide range of contrast levels (5.3-100% RMS contrast), in all subjects tested. In a whole brain analysis, this contrast polarity bias was largely confined to the Fusiform Face Area (FFA; p<0.0001), with possible involvement of a left occipital face-selective region. 2) It is known that reversing facial contrast affects three image properties in parallel (absorbance, shading, and specular reflection). Here, comparison of FFA responses to those in V1 suggests that the contrast polarity bias is produced in FFA only when all three component properties were reversed simultaneously, which suggests a prominent non-linearity in FFA processing. 3) Across a wide range (180°) of illumination source angles, 3D face shapes without texture produced response constancy in FFA, without a contrast polarity bias. 4) Consistent with psychophysics, analogous fMRI biases for normal contrast polarity were not produced by non-face objects, with image statistics similar to the face stimuli. 5) Using fMRI, we also demonstrated a contrast polarity bias in awake behaving macaque monkeys, in the cortical region considered homologous to human FFA. Thus common cortical mechanisms may underlie facial contrast processing across ~25 million years of primate evolution. PMID:23518007

Yue, Xiaomin; Nasr, Shahin; Devaney, Kathryn J; Holt, Daphne J; Tootell, Roger B H

2013-08-01

350

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity  

PubMed Central

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnamese-American family identified the ADDWOC causative locus on chromosome 2q36.1 with a multipoint parametric LOD score of 3.3, while haplotype analysis refined the locus to 1.1 Mb. Sequencing of the five known genes in this locus did not identify any protein-altering mutations. However, a terminal deletion of chromosome 2 in a patient with an isolated case of Dandy-Walker malformation also encompassed the 2q36.1 chromosomal region. The Brazilian pedigree did not show linkage to this 2q36.1 region. Taken together, these results demonstrate a locus for ADDWOC on 2q36.1 and also suggest locus heterogeneity for ADDWOC. PMID:18204864

Jalali, Ali; Aldinger, Kimberly A.; Chary, Ajit; Mclone, David G.; Bowman, Robin M.; Le, Luan Cong; Jardine, Phillip; Newbury-Ecob, Ruth; Mallick, Andrew; Jafari, Nadereh; Russell, Eric J.; Curran, John; Nguyen, Pam; Ouahchi, Karim; Lee, Charles; Dobyns, William B.; Millen, Kathleen J.; Pina-Neto, Joao M.; Kessler, John A.; Bassuk, Alexander G.

2010-01-01

351

The post-occipital spinal venous sinus of the Nile crocodile Crocodylus niloticus: its anatomy and use for blood sample collection and intravenous infusions.  

PubMed

The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions. PMID:24831995

Myburgh, Jan G; Kirberger, Robert M; Steyl, Johan C A; Soley, John T; Booyse, Dirk G; Huchzermeyer, Fritz W; Lowers, Russel H; Guillette, Louis J

2014-01-01

352

A new method for automated high-dimensional lesion segmentation evaluated in vascular injury and applied to the human occipital lobe  

PubMed Central

Making robust inferences about the functional neuroanatomy of the brain is critically dependent on experimental techniques that examine the consequences of focal loss of brain function. Unfortunately, the use of the most comprehensive such technique—lesion-function mapping—is complicated by the need for time-consuming and subjective manual delineation of the lesions, greatly limiting the practicability of the approach. Here we exploit a recently-described general measure of statistical anomaly, zeta, to devise a fully-automated, high-dimensional algorithm for identifying the parameters of lesions within a brain image given a reference set of normal brain images. We proceed to evaluate such an algorithm in the context of diffusion-weighted imaging of the commonest type of lesion used in neuroanatomical research: ischaemic damage. Summary performance metrics exceed those previously published for diffusion-weighted imaging and approach the current gold standard—manual segmentation—sufficiently closely for fully-automated lesion-mapping studies to become a possibility. We apply the new method to 435 unselected images of patients with ischaemic stroke to derive a probabilistic map of the pattern of damage in lesions involving the occipital lobe, demonstrating the variation of anatomical resolvability of occipital areas so as to guide future lesion-function studies of the region. PMID:23347558

Mah, Yee-Haur; Jager, Rolf; Kennard, Christopher; Husain, Masud; Nachev, Parashkev

2014-01-01

353

Inhibitory repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex modulates early affective processing.  

PubMed

The dorsolateral prefrontal cortex (dlPFC) has often been suggested as a key modulator of emotional stimulus appraisal and regulation. Therefore, in clinical trials, it is one of the most frequently targeted regions for non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). In spite of various encouraging reports that demonstrate beneficial effects of rTMS in anxiety disorders, psychophysiological studies exploring the underlying neural mechanisms are sparse. Here we investigated how inhibitory rTMS influences early affective processing when applied over the right dlPFC. Before and after rTMS or sham stimulation, subjects viewed faces with fearful or neutral expressions while whole-head magnetoencephalography (MEG) was recorded. Due to the disrupted functioning of the right dlPFC, visual processing in bilateral parietal, temporal, and occipital areas was amplified starting at around 90 ms after stimulus onset. Moreover, increased fear-specific activation was found in the right TPJ area in a time-interval between 110 and 170 ms. These neurophysiological effects were reflected in slowed reaction times for fearful, but not for neutral faces in a facial expression identification task while there was no such effect on a gender discrimination control task. Our study confirms the specific and important role of the dlPFC in regulation of early emotional attention and encourages future clinical research to use minimal invasive methods such as transcranial magnetic (TMS) or direct current stimulation (tDCS). PMID:25019678

Zwanzger, Peter; Steinberg, Christian; Rehbein, Maimu Alissa; Bröckelmann, Ann-Kathrin; Dobel, Christian; Zavorotnyy, Maxim; Domschke, Katharina; Junghöfer, Markus

2014-11-01

354

Phencyclidine and ketamine: comparison with the effect of cocaine on the noradrenergic neurones of the rat brain cortex.  

PubMed

In slices of rat occipital cortex, the influence of phencyclidine and ketamine on the accumulation of 3H-noradrenaline and the subsequent outflow of tritium was investigated, and was compared with the effect of cocaine.--All three drugs inhibited the accumulation of tritium during incubation of the slices with 3H-noradrenaline. Phencyclidine was slightly, whereas ketamine was much less effective than cocaine.--All three drugs accelerated the spontaneous outflow of tritium from slices preincubated with 3H-noradrenaline. The acceleration caused by low concentrations probably reflects an inhibition of the re-uptake of spontaneously released 3H-noradrenaline; in addition, high concentrations (10(-4) M phencyclidine, 3 X 10(-4)-10(-3) M cocaine and 10(-3)-3 X 10(-3) M ketamine) appear to release tritiated compounds from the neurones. The distance between uptake-inhibiting and releasing concentrations was much greater for cocaine than for phencyclidine and ketamine.--All three drugs enhanced the overflow of tritium evoked by electrical field stimulation. The increase probably reflects an inhibition of the re-uptake of released 3H-noradrenaline; in addition, phencyclidine appears to enhance the release of noradrenaline per pulse.--The actions of phencyclidine and ketamine on central noradrenergic neurones may contribute to the characteristic psychotropic side-effects of these general anaesthetics. PMID:1196407

Taube, H D; Montel, H; Hau, G; Starke, K

1975-01-01

355

Projections from Orbitofrontal Cortex to Anterior Piriform Cortex in the Rat Suggest a Role in Olfactory Information Processing  

PubMed Central

The orbitofrontal cortex (OFC) has been characterized as a higher-order, multimodal sensory cortex. Evidence from electrophysiological and behavioral studies in the rat has suggested that OFC plays a role in modulating olfactory guided behavior, and a significant projection to OFC arises from piriform cortex, the traditional primary olfactory cortex. To discern how OFC interacts with primary olfactory structures, the anterograde tracer Phaseolus vulgaris leucoagglutinin was injected into orbitofrontal cortical areas in adult male rats. Labeled fibers were found in the piriform cortex and olfactory bulb on the side ipsilateral to the injection. Notably, the projection to piriform cortex was predominantly from ventrolateral orbital cortex, and was not uniform; rostrally, the projection to the ventral portion of the anterior piriform cortex (APC) was substantial, while the dorsal APC was virtually free of labeled fibers. Labeled fibers were found in both the dorsal and ventral portions in more caudal regions of APC. Most labeled fibers were found in layer III, although a substantial number of fibers were observed in layers Ib and II. Labeled fibers in posterior piriform cortex also were seen after injection into orbitofrontal areas. Taken together with previous reports, these findings suggest that piriform cortex includes multiple subdivisions, which may perform separate, parallel functions in olfactory information processing. Further, these results suggest that the OFC, in addition to its putative role in encoding information about the significance of olfactory stimuli, may play a role in modulating odor response properties of neurons in piriform cortex. PMID:15924345

ILLIG, KURT R.

2006-01-01

356

Specificity and randomness in the visual cortex  

PubMed Central

Summary Research on the functional anatomy of visual cortical circuit has recently zoomed in from the macroscopic level to the microscopic. High-resolution functional imaging has revealed that the functional architecture of orientation maps in higher mammals is built with single-cell precision. In contrast, orientation selectivity in rodents is dispersed on visual cortex in a salt-and-pepper fashion, despite highly tuned visual responses. Recent studies of synaptic physiology indicate that there are disjoint subnetworks of interconnected cells in the rodent visual cortex. These intermingled subnetworks, described in vitro, may relate to the intermingled ensembles of cells tuned to different orientations, described in vivo. This hypothesis may soon be tested with new anatomic techniques that promise to reveal detailed wiring diagrams in cortical circuits. PMID:17720489

Ohki, Kenichi; Reid, R. Clay

2009-01-01

357

Reconstructing Speech from Human Auditory Cortex  

PubMed Central

How the human auditory system extracts perceptually relevant acoustic features of speech is unknown. To address this question, we used intracranial recordings from nonprimary auditory cortex in the human superior temporal gyrus to determine what acoustic information in speech sounds can be reconstructed from population neural activity. We found that slow and intermediate temporal fluctuations, such as those corresponding to syllable rate, were accurately reconstructed using a linear model based on the auditory spectrogram. However, reconstruction of fast temporal fluctuations, such as syllable onsets and offsets, required a nonlinear sound representation based on temporal modulation energy. Reconstruction accuracy was highest within the range of spectro-temporal fluctuations that have been found to be critical for speech intelligibility. The decoded speech representations allowed readout and identification of individual words directly from brain activity during single trial sound presentations. These findings reveal neural encoding mechanisms of speech acoustic parameters in higher order human auditory cortex. PMID:22303281

Pasley, Brian N.; David, Stephen V.; Mesgarani, Nima; Flinker, Adeen; Shamma, Shihab A.; Crone, Nathan E.; Knight, Robert T.; Chang, Edward F.

2012-01-01

358

Telocytes in the human kidney cortex  

PubMed Central

Renal interstitial cells play an important role in the physiology and pathology of the kidneys. As a novel type of interstitial cell, telocytes (TCs) have been described in various tissues and organs, including the heart, lung, skeletal muscle, urinary tract, etc. (www.telocytes.com). However, it is not known if TCs are present in the kidney interstitium. We demonstrated the presence of TCs in human kidney cortex interstitium using primary cell culture, transmission electron microscopy (TEM) and in situ immunohistochemistry (IHC). Renal TCs were positive for CD34, CD117 and vimentin. They were localized in the kidney cortex interstitial compartment, partially covering the tubules and vascular walls. Morphologically, renal TCs resemble TCs described in other organs, with very long telopodes (Tps) composed of thin segments (podomers) and dilated segments (podoms). However, their possible roles (beyond intercellular signalling) as well as their specific phenotype in the kidney remain to be established. PMID:23241355

Qi, Guisheng; Lin, Miao; Xu, Ming; Manole, C G; Wang, Xiangdong; Zhu, Tongyu

2012-01-01

359

Hierarchical Models of Object Recognition in Cortex  

E-print Network

The classical model of visual processing in cortex is a hierarchy of increasingly sophisticated representations, extending in a natural way the model of simple to complex cells of Hubel and Wiesel. Somewhat surprisingly, little quantitative modeling has been done in the last 15 years to explore the biological feasibility of this class of models to explain higher level visual processing, such as object recognition. We describe a new hierarchical model that accounts well for this complex visual task, is consistent with several recent physiological experiments in inferotemporal cortex and makes testable predictions. The model is based on a novel MAX-like operation on the inputs to certain cortical neurons which may have a general role in cortical function.

Maximilian Riesenhuber; Tomaso Poggio

1999-01-01

360

Area patterning of the mammalian cortex.  

PubMed

Here we describe mechanisms regulating area patterning of developing mammalian neocortex, referred to as arealization. Current findings indicate an interplay between intrinsic genetic mechanisms and extrinsic information relayed to cortex by thalamocortical input. Intrinsic mechanisms are based on morphogens and signaling molecules secreted by patterning centers, positioned at the perimeter of dorsal telencephalon, that generate across nascent cortex the graded expression of transcription factors in cortical progenitors. Two major patterning centers are the commissural plate, which expresses Fgf8 and Fgf17, and the cortical hem, which expresses Bmps and Wnts. Four transcription factors, COUP-TFI, Emx2, Pax6, and Sp8, with graded expression across the embryonic cortical axes, are shown to determine sizes and positions of cortical areas by specifying or repressing area identities within cortical progenitors. They also interact to modify their expression, as well as expression of Fgf8. We review these mechanisms of arealization and discuss models and concepts of cortical area patterning. PMID:17964244

O'Leary, Dennis D M; Chou, Shen-Ju; Sahara, Setsuko

2007-10-25

361

Anterior Insular Cortex and Emotional Awareness  

PubMed Central

This paper reviews the foundation for a role of the human anterior insular cortex (AIC) in emotional awareness, defined as the conscious experience of emotions. We first introduce the neuroanatomical features of AIC and existing findings on emotional awareness. Using empathy, the awareness and understanding of other people’s emotional states, as a test case, we then present evidence to demonstrate: 1) AIC and anterior cingulate cortex (ACC) are commonly coactivated as revealed by a meta-analysis, 2) AIC is functionally dissociable from ACC, 3) AIC integrates stimulus-driven and top-down information, and 4) AIC is necessary for emotional awareness. We propose a model in which AIC serves two major functions: integrating bottom-up interoceptive signals with top-down predictions to generate a current awareness state and providing descending predictions to visceral systems that provide a point of reference for autonomic reflexes. We argue that AIC is critical and necessary for emotional awareness. PMID:23749500

Gu, Xiaosi; Hof, Patrick R.; Friston, Karl J.; Fan, Jin

2014-01-01

362

The Auditory Cortex: The Final Frontier  

Microsoft Academic Search

\\u000a The auditory cortex consists of 10–15 interconnected areas or fields whose neurons receive a modest input from the thalamus\\u000a and about 10–100 times more input from other auditory cortical areas and nonauditory cortical fields from the same and contralateral\\u000a hemisphere. Modeling this conglomerate as a black box functional network model is potentially doable (Stephan et al. 2000),\\u000a but that does

Jos J. Eggermont

363

Claustral afferents to the rat's visual cortex.  

PubMed

Horseradish peroxidase (HRP) was injected electrophoretically into the rat's primary visual cortex (V1), and three other retinotopically organized cortical areas, anterior medial visual area (AM), posterior medial visual area (PM) and anterior lateral area (AL). While the HRP injections into V1 labelled many neurons in the ipsilateral claustrum, the injections in any of the three other visual areas labelled very few claustral neurons. PMID:6493606

Shameem, N; Sanderson, K; Dreher, B

1984-08-31

364

Evaluation of inputs to rat primary auditory cortex from the suprageniculate nucleus and extrastriate visual cortex  

PubMed Central

Evidence indicates that visual stimuli influence cells in primary auditory cortex. To evaluate potential sources of this visual input and how they enter into circuitry of the auditory cortex, we examined axonal terminations in primary auditory cortex from non-primary extrastriate visual cortex (V2M, V2L) and from the multimodal thalamic suprageniculate nucleus (SG). Gross biocytin/BDA injections into SG or extrastriate cortex labeled inputs terminating primarily in superficial and deep layers. SG projects primarily to layers I, V and VI, V2M and V2L project primarily to layers I and VI with V2L also targeting layers II/III. Layer I inputs differ in that SG terminals are concentrated superficially, V2L deeper and V2M are equally distributed throughout. Individual axonal reconstructions document that single axons can 1) innervate multiple layers, 2) run considerable distances in layer I, and 3) run preferentially in the dorsoventral direction similar to isofrequency axes. At the electron microscopic level SG and V2M terminals are 1) the same size regardless of layer, 2) non-GABAergic, 3) smaller than ventral medial geniculate terminals synapsing in layer IV and 4) make asymmetric synapses onto dendrites/spines which 5) are non-GABAergic and 6) are slightly larger in layer I. Thus, both areas provide a substantial feedback-like input with differences that may indicate potentially different roles. PMID:20653029

Smith, Philip; Manning, Karen A.; Uhlrich, Daniel J.

2010-01-01

365

Hemispherical map for the human brain cortex  

NASA Astrophysics Data System (ADS)

Understanding the function of the human brain cortex is a primary goal in human brain mapping. Methods to unfold and flatten the cortical surface for visualization and measurement have been described in previous literature; but comparison across multiple subjects is still difficult because of the lack of a standard mapping technique. We describe a new approach that maps each hemisphere of the cortex to a portion of a sphere in a standard way, making comparison of anatomy and function across different subjects possible. Starting with a three-dimensional magnetic resonance image of the brain, the cortex is segmented and represented as a triangle mesh. Defining a cut around the corpus collosum identifies the left and right hemispheres. Together, the two hemispheres are mapped to the complex plane using a conformal mapping technique. A Mobius transformation, which is conformal, is used to transform the points on the complex plane so that a projective transformation maps each brain hemisphere onto a spherical segment comprising a sphere with a cap removed. We determined the best size of the spherical cap by minimizing the relative area distortion between hemispherical maps and original cortical surfaces. The relative area distortion between the hemispherical maps and the original cortical surfaces for fifteen human brains is analyzed.

Tosun, Duygu; Prince, Jerry L.

2001-07-01

366

Amodal processing in human prefrontal cortex.  

PubMed

Information enters the cortex via modality-specific sensory regions, whereas actions are produced by modality-specific motor regions. Intervening central stages of information processing map sensation to behavior. Humans perform this central processing in a flexible, abstract manner such that sensory information in any modality can lead to response via any motor system. Cognitive theories account for such flexible behavior by positing amodal central information processing (e.g., "central executive," Baddeley and Hitch, 1974; "supervisory attentional system," Norman and Shallice, 1986; "response selection bottleneck," Pashler, 1994). However, the extent to which brain regions embodying central mechanisms of information processing are amodal remains unclear. Here we apply multivariate pattern analysis to functional magnetic resonance imaging (fMRI) data to compare response selection, a cognitive process widely believed to recruit an amodal central resource across sensory and motor modalities. We show that most frontal and parietal cortical areas known to activate across a wide variety of tasks code modality, casting doubt on the notion that these regions embody a central processor devoid of modality representation. Importantly, regions of anterior insula and dorsolateral prefrontal cortex consistently failed to code modality across four experiments. However, these areas code at least one other task dimension, process (instantiated as response selection vs response execution), ensuring that failure to find coding of modality is not driven by insensitivity of multivariate pattern analysis in these regions. We conclude that abstract encoding of information modality is primarily a property of subregions of the prefrontal cortex. PMID:23843526

Tamber-Rosenau, Benjamin J; Dux, Paul E; Tombu, Michael N; Asplund, Christopher L; Marois, René

2013-07-10

367

Parietal Cortex Signals Come Unstuck in Time  

PubMed Central

Humans and other animals are surprisingly adept at estimating the duration of temporal intervals, even without the use of watches and clocks. This ability is typically studied in the lab by asking observers to indicate their estimate of the time between two external sensory events. The results of such studies confirm that humans can accurately estimate durations on a variety of time scales. Although many brain areas are thought to contribute to the representation of elapsed time, recent neurophysiological studies have linked the parietal cortex in particular to the perception of sub-second time intervals. In this Primer, we describe previous work on parietal cortex and time perception, and we highlight the findings of a study published in this issue of PLOS Biology, in which Schneider and Ghose [1] characterize single-neuron responses during performance of a novel “Temporal Production” task. During temporal production, the observer must track the passage of time without anticipating any external sensory event, and it appears that the parietal cortex may use a unique strategy to support this type of measurement. PMID:23118615

Cook, Erik P.; Pack, Christopher C.

2012-01-01

368

Parietal cortex signals come unstuck in time.  

PubMed

Humans and other animals are surprisingly adept at estimating the duration of temporal intervals, even without the use of watches and clocks. This ability is typically studied in the lab by asking observers to indicate their estimate of the time between two external sensory events. The results of such studies confirm that humans can accurately estimate durations on a variety of time scales. Although many brain areas are thought to contribute to the representation of elapsed time, recent neurophysiological studies have linked the parietal cortex in particular to the perception of sub-second time intervals. In this Primer, we describe previous work on parietal cortex and time perception, and we highlight the findings of a study published in this issue of PLOS Biology, in which Schneider and Ghose characterize single-neuron responses during performance of a novel "Temporal Production" task. During temporal production, the observer must track the passage of time without anticipating any external sensory event, and it appears that the parietal cortex may use a unique strategy to support this type of measurement. PMID:23118615

Cook, Erik P; Pack, Christopher C

2012-01-01

369

Amodal Processing in Human Prefrontal Cortex  

PubMed Central

Information enters the cortex via modality-specific sensory regions, whereas actions are produced by modality-specific motor regions. Intervening central stages of information processing map sensation to behavior. Humans perform this central processing in a flexible, abstract manner such that sensory information in any modality can lead to response via any motor system. Cognitive theories account for such flexible behavior by positing amodal central information processing (e.g., “central executive,” Baddeley and Hitch, 1974; “supervisory attentional system,” Norman and Shallice, 1986; “response selection bottleneck,” Pashler, 1994). However, the extent to which brain regions embodying central mechanisms of information processing are amodal remains unclear. Here we apply multivariate pattern analysis to functional magnetic resonance imaging (fMRI) data to compare response selection, a cognitive process widely believed to recruit an amodal central resource across sensory and motor modalities. We show that most frontal and parietal cortical areas known to activate across a wide variety of tasks code modality, casting doubt on the notion that these regions embody a central processor devoid of modality representation. Importantly, regions of anterior insula and dorsolateral prefrontal cortex consistently failed to code modality across four experiments. However, these areas code at least one other task dimension, process (instantiated as response selection vs response execution), ensuring that failure to find coding of modality is not driven by insensitivity of multivariate pattern analysis in these regions. We conclude that abstract encoding of information modality is primarily a property of subregions of the prefrontal cortex. PMID:23843526

Dux, Paul E.; Tombu, Michael N.; Asplund, Christopher L.; Marois, René

2013-01-01

370

Neural structures underlying set-shifting: roles of medial prefrontal cortex and anterior cingulate cortex.  

PubMed

Impaired attentional set-shifting and inflexible decision-making are problems frequently observed during normal aging and in several psychiatric disorders. To understand the neuropathophysiology of underlying inflexible behavior, animal models of attentional set-shifting have been developed to mimic tasks such as the Wisconsin Card Sorting Task (WCST), which tap into a number of cognitive functions including stimulus-response encoding, working memory, attention, error detection, and conflict resolution. Here, we review many of these tasks in several different species and speculate on how prefrontal cortex and anterior cingulate cortex might contribute to normal performance during set-shifting. PMID:23664821

Bissonette, Gregory B; Powell, Elizabeth M; Roesch, Matthew R

2013-08-01

371

Long-Term Potentiation in the Motor Cortex  

NASA Astrophysics Data System (ADS)

Long-term potentiation (LTP) is a model for learning and memory processes. Tetanic stimulation of the sensory cortex produces LTP in motor cortical neurons, whereas tetanization of the ventrolateral nucleus of the thalamus, which also projects to the motor cortex, does not. However, after simultaneous high-frequency stimulation of both the sensory cortex and the ventrolateral nucleus of the thalamus, LTP of thalamic input to motor cortical neurons is induced. This associative LTP occurs only in neurons in the superficial layers of the motor cortex that receive monosynaptic input from both the sensory cortex and the ventrolateral nucleus of the thalamus. Associative LTP in the motor cortex may constitute a basis for the retention of motor skills.

Iriki, Atsushi; Pavlides, Constantine; Keller, Asaf; Asanuma, Hiroshi

1989-09-01

372

A Comparative Volumetric Analysis of the Prefrontal Cortex in Human and Baboon MRI  

Microsoft Academic Search

The proportion of prefrontal cortex in humans was compared to the proportion of prefrontal cortex in baboons (Papio anubis). Prefrontal cortex, dorsal prefrontal, orbital prefrontal cortex and total brain volumes were determined from magnetic resonance images of 20 healthy adult human females and 5 adult female baboons. Results showed that the proportion of prefrontal cortex volume relative to total brain

Thomas McBride; Steven E. Arnold; Ruben C. Gur

1999-01-01

373

Aging, self-referencing, and medial prefrontal cortex  

Microsoft Academic Search

The lateral prefrontal cortex undergoes both structural and functional changes with healthy aging. In contrast, there is little structural change in the medial prefrontal cortex, but relatively little is known about the functional changes to this region with age. Using an event-related fMRI design, we investigated the response of medial prefrontal cortex during self-referencing in order to compare age groups

Angela H. Gutchess; Elizabeth A. Kensinger; Daniel L. Schacter

2007-01-01

374

Serial and parallel processing in rhesus monkey auditory cortex  

Microsoft Academic Search

Auditory cortex on the exposed supratemporal plane in four anesthetized rhesus monkeys was mapped electrophysiologically with both pure-tone (PT) and broad-band complex sounds. The mapping confirmed the existence of at least three tonotopic areas. Primary auditory cortex, AI, was then aspirated, and the remainder of the cortex on the supratemporal plane was remapped. PT-responses in the caudomedial area, CM, were

Josef P. Rauschecker; Biao Tian; Timothy Pons; Mortimer Mishkin

1997-01-01

375

Ictal Generalized EEG Attenuation (IGEA) and hypopnea in a child with occipital type 1 cortical dysplasia - Is it a biomarker for SUDEP?  

PubMed

An interesting association of ictal hypopnea and ictal generalized EEG attenuation (IGEA) as possible marker of sudden unexpected death in epilepsy (SUDEP) is reported. We describe a 5-years-old girl with left focal seizures with secondary generalization due to right occipital cortical dysplasia presenting with ictal hypopnea and IGEA. She had repeated episodes of the ictal apnoea in the past requiring ventilator support and intensive care unit (ICU) admission during episodes of status epilepticus. The IGEA lasted for 0.26-4.68 seconds coinciding with the ictal hypopnea during which both clinical seizure and electrical epileptic activity stopped. Review of literature showed correlation between post-ictal apnoea and post ictal generalized EEG suppression and increased risk for SUDEP. The report adds to the growing body of literature on peri-ictal apnea, about its association with IGEA might be considered as a marker for SUDEP. She is seizure free for 4 months following surgery. PMID:25745325

Chaitanya, Ganne; Santosh, N Subbareddy; Velmurugan, Jayabal; Arivazhagan, Arima; Bharath, Rose D; Mahadevan, Anita; Nagappa, Madhu; Bindu, Parayil S; Rao, Malla Bhaskara; Taly, Arun B; Satishchandra, Parthasarathy; Sinha, Sanjib

2015-01-01

376

Similar splicing mutations of the Menkes/mottled copper-transporting ATPase gene in occipital horn syndrome and the blotchy mouse.  

PubMed Central

The connective-tissue disorder occipital horn syndrome (OHS) is hypothesized to be allelic to Menkes disease. The two diseases have different clinical presentations but have a similar abnormality of copper transport. Mice hemizygous for the blotchy allele of the X-linked mottled locus have similar connective-tissue defects as OHS and may represent a mouse model of this disease. We have analyzed the Menkes/mottled copper-transporting ATPase in these two potentially homologous disorders and have identified similar splicing mutations in both. Some expression of normal mRNA was detectable by reverse transcription-PCR in the mutant tissues. These findings contrast with the more debilitating mutations observed in Menkes disease and suggest that low amounts of an otherwise normal protein product could result in the relatively mild phenotype of OHS and of the blotchy mouse. Images Figure 1 Figure 2 PMID:7887410

Das, S; Levinson, B; Vulpe, C; Whitney, S; Gitschier, J; Packman, S

1995-01-01

377

Chiari I Malformation Associated with Atlanto-Occipital Assimilation Presenting as Orthopnea and Cough Syncope: A Case Report and Review of Literature  

PubMed Central

Although it is not uncommon for patients with Chiari I malformations to present with respiratory complaints, cough syncope is a rare presenting symptom. We report an adult patient who harbored both a Chiari I malformation and atlanto-occipital assimilation who complained of cough syncope, orthopnea, and central sleep apnea. The patient underwent decompressive craniectomy of the posterior fossa and cervical level 2 laminectomy. However, due to a possible initial underappreciation of the profound narrowing of the foramen magnum as a result of these concomitant pathologies, the patient may have had continued impaired cerebrospinal fluid flow, leading to a symptomatic pseudomeningocele and requiring a more extensive decompression that included a cervical level 3 laminectomy as well as a temporary lumbar drain. On 2-year follow-up, he has remained asymptomatic. PMID:25083365

Mangubat, Erwin Zeta; Wilson, Tom; Mitchell, Brian A.; Byrne, Richard W.

2013-01-01

378

Ictal Generalized EEG Attenuation (IGEA) and hypopnea in a child with occipital type 1 cortical dysplasia – Is it a biomarker for SUDEP?  

PubMed Central

An interesting association of ictal hypopnea and ictal generalized EEG attenuation (IGEA) as possible marker of sudden unexpected death in epilepsy (SUDEP) is reported. We describe a 5-years-old girl with left focal seizures with secondary generalization due to right occipital cortical dysplasia presenting with ictal hypopnea and IGEA. She had repeated episodes of the ictal apnoea in the past requiring ventilator support and intensive care unit (ICU) admission during episodes of status epilepticus. The IGEA lasted for 0.26-4.68 seconds coinciding with the ictal hypopnea during which both clinical seizure and electrical epileptic activity stopped. Review of literature showed correlation between post-ictal apnoea and post ictal generalized EEG suppression and increased risk for SUDEP. The report adds to the growing body of literature on peri-ictal apnea, about its association with IGEA might be considered as a marker for SUDEP. She is seizure free for 4 months following surgery.

Chaitanya, Ganne; Santosh, N. Subbareddy; Velmurugan, Jayabal; Arivazhagan, Arima; Bharath, Rose D.; Mahadevan, Anita; Nagappa, Madhu; Bindu, Parayil S; Rao, Malla Bhaskara; Taly, Arun B.; Satishchandra, Parthasarathy; Sinha, Sanjib

2015-01-01

379

Gateways of ventral and dorsal streams in mouse visual cortex  

PubMed Central

It is widely held that the spatial processing functions underlying rodent navigation are similar to those encoding human episodic memory (Doeller et al, 2010). Spatial and nonspatial information are provided by all senses including vision. It has been suggested that visual inputs are fed to the navigational network in cortex and hippocampus through dorsal and ventral intracortical streams (Whitlock et al, 2008), but this has not been shown directly in rodents. We have used cyto- and chemoarchitectonic markers, topographic mapping of receptive fields and pathway tracing to determine in mouse visual cortex whether the lateromedial (LM) and the anterolateral fields (AL), which are the principal targets of primary visual cortex (V1) (Wang and Burkhalter, 2007) specialized for processing nonspatial and spatial visual information (Gao et al, 2006), are distinct areas with diverse connections. We have found that the LM/AL border coincides with a change in type 2 muscarinic acetylcholine receptor (m2AChR) expression in layer 4 and with the representation of the lower visual field periphery. Our quantitative analyses further show that LM strongly projects to temporal cortex as well as the lateral entorhinal cortex, which has weak spatial selectivity (Hargreaves et al, 2005). In contrast, AL has stronger connections with posterior parietal cortex, motor cortex and the spatially selective medial entorhinal cortex (Haftig et al, 2005). These results support the notion that LM and AL are architecturally, topographically and connectionally distinct areas of extrastriate visual cortex and that they are gateways for ventral and dorsal streams. PMID:21289200

Wang, Quanxin; Gao, Enquan; Burkhalter, Andreas

2011-01-01

380

Object decoding with attention in inferior temporal cortex  

E-print Network

Recognizing objects in cluttered scenes requires attentional mechanisms to filter out distracting information. Previous studies have found several physiological correlates of attention in visual cortex, including larger ...

Zhang, Ying

381

Representation of Multiple, Independent Categories in the Primate Prefrontal Cortex  

E-print Network

Neural correlates of visual categories have been previously identified in the prefrontal cortex (PFC). However, whether individual neurons can represent multiple categories is unknown. Varying degrees of generalization ...

Cromer, Jason A.

382

Retinotopic Organization of Human Ventral Visual Cortex  

PubMed Central

Functional magnetic resonance imaging (fMRI) studies have shown that human ventral visual cortex anterior to area hV4 contains two visual field maps, VO-1 and VO-2, that together form the VO-cluster (Brewer et al., 2005). This cluster is characterized by common functional response properties and responds preferentially to color and object stimuli. Here, we confirm the topographic and functional characteristics of the VO-cluster and describe two new visual field maps that are located anterior to VO-2 extending across the collateral sulcus into the posterior parahippocampal cortex (PHC). We refer to these visual field maps as parahippocampal areas PHC-1 and PHC-2. Each PHC map contains a topographic representation of contralateral visual space. The polar angle representation in PHC-1 extends from regions near the lower vertical meridian (that is the shared border with VO-2) to those close to the upper vertical meridian (that is the shared border with PHC-2). The polar angle representation in PHC-2 is a mirror-reversal of the PHC-1 representation. PHC-1 and PHC-2 share a foveal representation and show a strong bias towards representations of peripheral eccentricities. Both the foveal and peripheral representations of PHC-1 and PHC-2 respond more strongly to scenes than to objects or faces, with greater scene preference in PHC-2 than PHC-1. Importantly, both areas heavily overlap with the functionally defined parahippocampal place area (PPA). Our results suggest that ventral visual cortex can be subdivided on the basis of topographic criteria into a greater number of discrete maps than previously thought. PMID:19710316

Arcaro, Michael J.; McMains, Stephanie A.; Singer, Benjamin D.; Kastner, Sabine

2009-01-01

383

Interhemispheric inhibition of the human motor cortex.  

PubMed Central

1. Using two magnetic stimulators, we investigated the effect of a conditioning magnetic stimulus over the motor cortex of one hemisphere on the size of EMG responses evoked in the first dorsal interosseous (FDI) muscle by a magnetic test stimulus given over the opposite hemisphere. 2. A single conditioning shock to one hemisphere produced inhibition of the test response evoked from the opposite hemisphere when the conditioning-test interval was 5-6 ms or longer. We shall refer to this as interhemispheric inhibition. However, the minimum latency of inhibition observed using surface EMG responses may have underestimated the true interhemispheric conduction time. Single motor unit studies suggested values 4-7 ms longer than the minimum interval observed with surface EMG. 3. Interhemispheric inhibition was seen when the test muscle was active or relaxed. Increasing the intensity of the conditioning stimulus increased the duration of inhibition: increasing the intensity of the test stimulus reduced the depth of inhibition. 4. The conditioning coil had to be placed on the appropriate area of scalp for inhibition to occur. The effect of the conditioning stimulus was maximal when it was applied over the hand area of motor cortex, and decreased when the stimulus was moved medial or lateral to that point. 5. The inhibitory effect on the test stimulus probably occurred at the level of the cerebral cortex. In contrast to the inhibition of test responses evoked by magnetic test stimuli, test responses evoked in active FDI by a small anodal electric shock were not significantly inhibited by a contralateral magnetic conditioning stimulus. Similarly, H reflexes in relaxed forearm flexor muscles were unaffected by conditioning stimuli to the ipsilateral hemisphere. However, inhibition was observed if the experiment was repeated with the muscles active. PMID:1464843

Ferbert, A; Priori, A; Rothwell, J C; Day, B L; Colebatch, J G; Marsden, C D

1992-01-01

384

Vestibular projections in the human cortex.  

PubMed

There is considerable evidence from studies on cats and monkeys that several cortical areas such as area 2v at the tip of the intraparietal sulcus, area 3av in the sulcus centralis, the parietoinsular vestibular cortex adjacent to the posterior insula (PIVC) and area 7 in the inferior parietal lobule are involved in the processing of vestibular information. Microelectrode recordings from these areas have shown that: (1) most of these cortical neurons are connected trisynaptically to the labyrinthine endorgans and (2) they receive converging vestibular, visual and somatosensory inputs. These data suggest that a multimodal cortical system is involved in postural and gaze control. In humans, recent positron emission tomography (PET) scans and functional magnetic resonance imaging (fMRI) studies have largely confirmed these data. However, because of the limited temporal resolution of these two methods, the minimum time of arrival of labyrinthine inputs from the vestibular hair cells to these cortical areas has not yet been determined. In this study, we used the evoked potential method to attempt to answer this question. Due to its excellent temporal resolution, this method is ideal for the investigation of the tri- or polysynaptic nature of the vestibulocortical pathways. Eleven volunteer patients, who underwent a vestibular neurectomy due to intractable Meniere's disease (MD) or acoustic neurinoma resection, were included in this experiment. Patients were anesthetized and the vestibular nerve was electrically stimulated. The evoked potentials were recorded by 30 subcutaneous active electrodes located on the scalp. The brain electrical source imaging (BESA) program (version 2.0, 1995) was used to calculate dipole sources. The latency period for the activation of five distinct cortical zones, including the prefrontal and/or the frontal lobe, the ipsilateral temporoparietal cortex, the anterior portion of the supplementary motor area (SMA) and the contralateral parietal cortex, was 6 ms. The short latency period recorded for each of these areas indicates that several trisynaptic pathways, passing through the vestibular nuclei and the thalamic neurons, link the primary vestibular afferents to the cortex. We suggest that all these areas, including the prefrontal area, process egomotion information and may be involved in planning motor synergies to counteract loss of equilibrium. PMID:11810147

de Waele, C; Baudonnière, P M; Lepecq, J C; Tran Ba Huy, P; Vidal, P P

2001-12-01

385

Perirhinal Cortex Lesions Impair Context Aversion Learning  

PubMed Central

Rats with perirhinal cortex lesions were compared with sham controls on a conditional discrimination in which saccharin was paired with LiCl in context 1, but paired with saline in context 2. Perirhinal-lesioned rats were slightly slower to acquire the discrimination but reached control levels by the end of acquisition. Both groups showed transfer to familiar tap water, consuming less in context 1 than in context 2. Unlike sham rats, perirhinal rats failed to show an aversion to context 1 on a place choice test. These data provide neuroanatomical support for the postulated difference between Pavlovian conditioning and conditional learning. PMID:12773580

Howse, Dana J.; Squires, Amanda S.; Martin, Gerard M.; Skinner, Darlene M.

2003-01-01

386

Functional Organization of Human Intraparietal and Frontal Cortex for Attending, Looking, and Pointing  

E-print Network

Functional Organization of Human Intraparietal and Frontal Cortex for Attending, Looking, Missouri 63110 We studied the functional organization of human posterior parietal and frontal cortex using pointing Introduction The functional organization of human posterior parietal cortex (PPC) and its

Van Essen, David

387

Behavioral/Systems/Cognitive Dorsolateral Prefrontal Cortex Promotes Long-Term  

E-print Network

Behavioral/Systems/Cognitive Dorsolateral Prefrontal Cortex Promotes Long-Term Memory Formation from neuroimaging studies have shown that the dorsolateral prefrontal cortex (DLPFC) implements that require WM maintenance. More dorsolateral prefrontal areas [dorsolateral prefrontal cortex (DLPFC

Murray, Scott

388

Emotion-Modulated Performance and Activity in Left Dorsolateral Prefrontal Cortex  

E-print Network

Emotion-Modulated Performance and Activity in Left Dorsolateral Prefrontal Cortex John D words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant affect, dorsolateral prefrontal cortex, functional MRI, brain asymmetry Emotion influences cognition

Banich, Marie T.

389

Dynamic Representation of Eye Position in the Parieto-Occipital Sulcus K. NAKAMURA, H. H. CHUNG, M.S.A. GRAZIANO, AND C. G. GROSS  

E-print Network

.S.A. GRAZIANO, AND C. G. GROSS Department of Psychology, Green Hall, Princeton University, Princeton, New Jersey 08544 Nakamura, K., H. H. Chung, M.S.A. Graziano, and C. G. Gross. Dynamic representation of eye al. 1993; Graziano et al. 1994b). In the dorsomedial frontal cortex (DMFC), the neurons

Graziano, Michael

390

Vibrissae motor cortex unit activity during whisking.  

PubMed

Rats generate stereotyped exploratory (5-12 Hz) vibrissa movements when navigating through their environment. Like other rhythmic behaviors, the production of whisking relies on a subcortical pattern generator. However, the relatively large vibrissae representation in motor cortex (vMCx) suggests that cortex also contributes to the control of whisker movements. The goal of this study was to examine the relationship between neuronal activity in vMCx and the kinematics of vibrissae movements. We recorded multiunit activity (MUA) and single units in the rhythmic region of vMCx while measuring vibrissa position in awake, head-restrained rats. The rats were engaged in one of two behavioral tasks where they were rewarded for either 1) producing noncontact whisking epochs that met specified criteria (epochs ?4 Hz, whisks >5 mm) or 2) whisking to contact an object. There was significant coherence between the frequency of MUA and vibrissae movements during free-air whisking but not when animals were using their vibrissae to contact an object. Spike rate in vMCx was most frequently correlated with the amplitude of vibrissa movements; correlations with movement frequency did not exceed chance levels. These findings suggest that the specific parameter under cortical control may be the amplitude of whisker movements. PMID:21994257

Friedman, Wendy A; Zeigler, H Philip; Keller, Asaf

2012-01-01

391

The state of somatosensory cortex during neuromodulation  

PubMed Central

During behavioral quiescence, such as slow-wave sleep and anesthesia, the neocortex is in a deactivated state characterized by the presence of slow oscillations. During arousal, slow oscillations are absent and the neocortex is in an activated state that greatly impacts information processing. Neuromodulators acting in neocortex are believed to mediate these state changes, but the mechanisms are poorly understood. We investigated the actions of noradrenergic and cholinergic activation on slow oscillations, cellular excitability, and synaptic inputs in thalamocortical slices of somatosensory cortex. The results show that neuromodulation abolishes slow oscillations, dampens the excitability of principal cells, and rebalances excitatory and inhibitory synaptic inputs in thalamocortical-recipient layers IV–III. Sensory cortex is much more selective about the inputs that can drive it. The source of neuromodulation is critically important in determining this selectivity. Cholinergic activation suppresses the excitatory and inhibitory conductances driven by thalamocortical and intracortical inputs. Noradrenergic activation suppresses the excitatory conductance driven by intracortical inputs but not by thalamocortical inputs and enhances the inhibitory conductance driven by thalamocortical inputs but not by intracortical inputs. Thus noradrenergic activation emphasizes thalamocortical (sensory) inputs relative to intracortical inputs, while cholinergic activation suppresses both. PMID:22623484

Favero, Morgana; Varghese, Gladis

2012-01-01

392

Probabilistic functional tractography of the human cortex.  

PubMed

Single-pulse direct electrical stimulation of cortical regions in patients suffering from focal drug-resistant epilepsy who are explored using intracranial electrodes induces cortico-cortical potentials that can be used to infer functional and anatomical connectivity. Here, we describe a neuroimaging framework that allows development of a new probabilistic atlas of functional tractography of the human cortex from those responses. This atlas is unique because it allows inference in vivo of the directionality and latency of cortico-cortical connectivity, which are still largely unknown at the human brain level. In this technical note, we include 1535 stimulation runs performed in 35 adult patients. We use a case of frontal lobe epilepsy to illustrate the asymmetrical connectivity between the posterior hippocampal gyrus and the orbitofrontal cortex. In addition, as a proof of concept for group studies, we study the probabilistic functional tractography between the posterior superior temporal gyrus and the inferior frontal gyrus. In the near future, the atlas database will be continuously increased, and the methods will be improved in parallel, for more accurate estimation of features of interest. Generated probabilistic maps will be freely distributed to the community because they provide critical information for further understanding and modelling of large-scale brain networks. PMID:23707583

David, Olivier; Job, Anne-Sophie; De Palma, Luca; Hoffmann, Dominique; Minotti, Lorella; Kahane, Philippe

2013-10-15

393

Abnormal Asymmetry in Language Association Cortex in Autism  

E-print Network

Abnormal Asymmetry in Language Association Cortex in Autism Martha R. Herbert, MD, PhD,1 Gordon J Masanori Takeoka, MD,7 Helen Tager-Flusberg, PhD,4 and Verne S. Caviness, Jr., MD1 Autism- related cortex in autistic and control subjects. Subjects included 16 boys with autism (aged 7­11 years

Chabris, Christopher F.

394

Mapping the Structural Core of Human Cerebral Cortex  

Microsoft Academic Search

Structurally segregated and functionally specialized regions of the human cerebral cortex are interconnected by a dense network of cortico-cortical axonal pathways. By using diffusion spectrum imaging, we noninvasively mapped these pathways within and across cortical hemispheres in individual human participants. An analysis of the resulting large-scale structural brain networks reveals a structural core within posterior medial and parietal cerebral cortex,

Patric Hagmann; Leila Cammoun; Xavier Gigandet; Reto Meuli; Christopher J. Honey; Van J. Wedeen; Olaf Sporns

2008-01-01

395

Reduced Anterior Cingulate Cortex Glutamatergic Concentrations in Childhood Major Depression  

ERIC Educational Resources Information Center

Objective: To examine in vivo glutamatergic neurochemical alterations in the anterior cingulate cortex of children with major depressive disorder (MDD). Method: Single-voxel proton magnetic resonance spectroscopic ([.sup.1]H-MRS) examinations of the anterior cingulate cortex were conducted in 13 psychotropic-naive children and adolescents with MDD…

Mirza, Yousha; Tang, Jennifer; Russell, Aileen; Banerjee, S. Preeya; Bhandari, Rashmi; Ivey, Jennifer; Rose, Michelle; Moore, Gregory J.; Rosenberg, David R.

2004-01-01

396

Projections From Auditory Cortex to Cochlear Nucleus: A Comparative  

E-print Network

Projections From Auditory Cortex to Cochlear Nucleus: A Comparative Analysis of Rat and Mouse NOAH were injected into AI. The cochlear nucleus was dissected and examined for terminal fibers by light cells of the cochlear nucleus. This report provides evidence for direct auditory cortex projections

Ryugo, David K.

397

Thickening in the somatosensory cortex of patients with migraine  

E-print Network

Thickening in the somatosensory cortex of patients with migraine Alexandre F.M. DaSilva, DDS, DMSc changes in the somatosensory cortex (SSC) of patients with migraine. Methods: Cortical thickness of the SSC of patients with migraine was measured in vivo and com- pared with age- and sex-matched healthy

Hadjikhani, Nouchine

398

Olfactocentric Paralimbic Cortex Morphology in Adolescents with Bipolar Disorder  

ERIC Educational Resources Information Center

The olfactocentric paralimbic cortex plays a critical role in the regulation of emotional and neurovegetative functions that are disrupted in core features of bipolar disorder. Adolescence is thought to be a critical period in both the maturation of the olfactocentric paralimbic cortex and in the emergence of bipolar disorder pathology. Together,…

Wang, Fei; Kalmar, Jessica H.; Womer, Fay Y.; Edmiston, Erin E.; Chepenik, Lara G.; Chen, Rachel; Spencer, Linda; Blumberg, Hilary P.

2011-01-01

399

Activity in Prelimbic Cortex Subserves Fear Memory Reconsolidation over Time  

ERIC Educational Resources Information Center

The prelimbic cortex has been implicated in the consolidation of previously learned fear. Herein, we report that temporarily inactivating this medial prefrontal cortex subregion with the GABA [subscript A] agonist muscimol (4.0 nmol in 0.2 µL per hemisphere) was able to equally disrupt 1-, 7-, and 21-d-old contextual fear memories after their…

Stern, Cristina A. J.; Gazarini, Lucas; Vanvossen, Ana C.; Hames, Mayara S.; Bertoglio, Leandro J.

2014-01-01

400

Frontal Cortex and Response Suppression in the Rat  

Microsoft Academic Search

Parts of the rails neocortex were mapped for sites where electrical stimulation, square waves at 10\\/sec, will suppress a bar-press response for food. Effective sites were found in the frontal pole and over most of the frontal dorsolateral cortex. Within these regions the strongest inhibitory influences were at sites in the frontal pole and adjacent frontal cortex, and at sites

R. C. Wilcott; B. A. Sabol; R. P. Yurcheshen

1976-01-01

401

Representation of Cochlea Within Primav Auditory Cortex in the Cat  

E-print Network

Representation of Cochlea Within Primav Auditory Cortex in the Cat MICHAEL M. MERZENPCH, PAUL L of the cochlear basilar par- tition in the auditory region of the cerebral cortex of the cat. Their classic evoked patches in the dog (54-56) and cat (26) substanti- ated these conclusions. The former studies more

Kilgard, Michael P.

402

Electrophysiological indices of sleep in the cerebral cortex  

NASA Technical Reports Server (NTRS)

An electrophysiological investigation of the nerve structures in which sleep inhibition develops is discussed. Twenty-four points of the cat's brain were selected for recordings. It was found that the anterior cortex produced delta waves in the initial period of sleep. The waves subsequently spread over the entire cortex. Subsequent investigation reveals similar facts pertinent to other waves in subsequent stages.

Kogan, A. B.; Feldman, G. L.

1973-01-01

403

Zinc-rich synaptic boutons in human temporal cortex biopsies  

Microsoft Academic Search

The distribution of zinc-rich synaptic boutons in biopsies of the temporal cortex from epileptic patients who had undergone surgery is described. Unfixed cryostat sections were exposed to H2S vapour to precipitate endogenous zinc, which was subsequently shown by silver enhancement. In the temporal cortex, the stain for zinc was arranged in bands: stain was heavy in layers II and VI,

N Franco-Pons; C Casanovas-Aguilar; S Arroyo; J Rumià; J Pérez-Clausell; G Danscher

2000-01-01

404

Multiple Somatosensory Areas in the Anterior Parietal Cortex  

E-print Network

Multiple Somatosensory Areas in the Anterior Parietal Cortex of the California Ground Squirrel of the California ground squirrel contains multiple representations of the sensory epithelium. This work, as well electrophysiological recording techniques were used to explore the somatosen- sory cortex of the California ground

Krubitzer, Leah A.

405

Cerebral Cortex doi:10.1093/cercor/bhr228  

E-print Network

squirrel (Sciurus carolinensis) and cortical connec- tions of motor cortex in the California ground of Motor Cortex in Squirrels Dylan F. Cooke1 , Jeffrey Padberg2 , Tony Zahner1,3 and Leah Krubitzer1,3 1 Center for Neuroscience, University of California, Davis, Davis, CA 95618, USA, 2 Department of Biology

Krubitzer, Leah A.

406

Responses of human visual cortex to uniform surfaces  

Microsoft Academic Search

Surface perception is fundamental to human vision, yet most studies of visual cortex have focused on the processing of borders. We therefore investigated the responses of human visual cortex to parametric changes in the luminance of uniform surfaces by using functional MRI. Early visual areas V1 and V2\\/V3 showed strong and reliable increases in signal for both increments and decrements

John-Dylan Haynes; R. Beau Lotto; Geraint Rees

2004-01-01

407

Borderline Personality Disorder, Impulsivity, and the Orbitofrontal Cortex  

Microsoft Academic Search

Objective: Orbitofrontal cortex lesions produce disinhibited or socially inappro- priate behavior and emotional irregulari- ties. Characteristics of borderline person- ality disorder include impulsivity and affective instability. The authors investi- gated whether aspects of borderline per- sonality disorder, in particular impulsivity, are associated with orbitofrontal cortex dysfunction. Method: Measures of personality, emo- tion, impulsivity, time perception, sensi- tivity to reinforcers, and

Heather A. Berlin; D. Phil; M. P. H. Edmund; T. Rolls; Susan D. Iversen

2005-01-01

408

Successful cryopreservation of human ovarian cortex tissues using supercooling  

PubMed Central

The development of new method to cryopreserve human ovarian cortex tissues without damage is needed for the improvement of quality of life (QOL) of female cancer patients. Here we show novel cryopreservation method of human ovarian cortex tissues by using supercooling (S.C.) procedure. Our method will be helpful in order to preserve fertility of female cancer patients. PMID:22844578

Moriguchi, Hisashi; Zhang, Yue; Mihara, Makoto; Sato, Chifumi

2012-01-01

409

Modulation of motor cortex excitability induced by pinch grip repetition  

Microsoft Academic Search

Summary. We examined the influence of right handed pinch grips and the effect of a motor training on motor cortex excitability of the left first dorsal interosseus muscle (FDI). TMS single and paired pulses were applied over the right human motor cortex (M1) during and after right handed pinch grips with low force. In another experiment, these stimulations were performed

A. Gorsler; S. Zittel; C. Weiller; A. Münchau; J. Liepert

2004-01-01

410

The scaling of frontal cortex in primates and carnivores  

E-print Network

The scaling of frontal cortex in primates and carnivores Eliot C. Bush* and John M. Allman Biology primates and 15 carnivores. We find evidence for significant differences in scaling between pri- mates and carnivores. Primate frontal cortex hyperscales relative to the rest of neocortex and the rest of the brain

Allman, John M.

411

THE ORGANIZATION OF BEHAVIORAL REPERTOIRE IN MOTOR CORTEX  

Microsoft Academic Search

Motor cortex in the primate brain was once thought to contain a simple map of the body's muscles. Recent evidence suggests, how- ever, that it operates at a radically more complex level, coordinat- ing behaviorally useful actions. Specific subregions of motor cortex may emphasize different ethologically relevant categories of behav- ior, such as interactions between the hand and the mouth,

Michael Graziano

2006-01-01

412

Mapping Striate and Extrastriate Visual Areas in Human Cerebral Cortex  

Microsoft Academic Search

Functional magnetic resonance imaging (fMRI) was used to identify and map the representation of the visual field in seven areas of human cerebral cortex and to identify at least two additional visually responsive regions. The cortical locations of neurons responding to stimulation along the vertical or horizontal visual field meridia were charted on three-dimensional models of the cortex and on

Edgar A. Deyoe; George J. Carman; Peter Bandettini; Seth Glickman; Jon Wieser; Robert Cox; David Miller; Jay Neitz

1996-01-01

413

Taste-related activity in the human dorsolateral prefrontal cortex  

Microsoft Academic Search

Taste remains one of the least-explored human senses. Cortical taste responses were investigated using neuroimaging in 40 subjects tasting a range of different taste stimuli compared to a neutral tasteless control. Activation was found in the anterior insula\\/frontal opercular taste cortex and caudal orbitofrontal cortex, both areas established as taste cortical areas by neuronal recordings in primates. A novel finding

Morten L. Kringelbach; Ivan E. T de Araujo; Edmund T Rolls

2004-01-01

414

Discourse Production Following Injury to the Dorsolateral Prefrontal Cortex  

ERIC Educational Resources Information Center

Individuals with damage to the prefrontal cortex, and the dorsolateral prefrontal cortex (DLPFC) in particular, often demonstrate difficulties with the formulation of complex language not attributable to aphasia. The present study employed a discourse analysis procedure to characterize the language of individuals with left (L) or right (R) DLPFC…

Coelho, Carl; Le, Karen; Mozeiko, Jennifer; Krueger, Frank; Grafman, Jordan

2012-01-01

415

Metaphorically Feeling: Comprehending Textural Metaphors Activates Somatosensory Cortex  

ERIC Educational Resources Information Center

Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging…

Lacey, Simon; Stilla, Randall; Sathian, K.

2012-01-01

416

Insular Cortex Is Involved in Consolidation of Object Recognition Memory  

ERIC Educational Resources Information Center

Extensive evidence indicates that the insular cortex (IC), also termed gustatory cortex, is critically involved in conditioned taste aversion and taste recognition memory. Although most studies of the involvement of the IC in memory have investigated taste, there is some evidence that the IC is involved in memory that is not based on taste. In…

Bermudez-Rattoni, Federico; Okuda, Shoki; Roozendaal, Benno; McGaugh, James L.

2005-01-01

417

A motor cortex circuit for motor planning and movement.  

PubMed

Activity in motor cortex predicts specific movements seconds before they occur, but how this preparatory activity relates to upcoming movements is obscure. We dissected the conversion of preparatory activity to movement within a structured motor cortex circuit. An anterior lateral region of the mouse cortex (a possible homologue of premotor cortex in primates) contains equal proportions of intermingled neurons predicting ipsi- or contralateral movements, yet unilateral inactivation of this cortical region during movement planning disrupts contralateral movements. Using cell-type-specific electrophysiology, cellular imaging and optogenetic perturbation, we show that layer 5 neurons projecting within the cortex have unbiased laterality. Activity with a contralateral population bias arises specifically in layer 5 neurons projecting to the brainstem, and only late during movement planning. These results reveal the transformation of distributed preparatory activity into movement commands within hierarchically organized cortical circuits. PMID:25731172

Li, Nuo; Chen, Tsai-Wen; Guo, Zengcai V; Gerfen, Charles R; Svoboda, Karel

2015-03-01

418

Cortical spectroscopy: localized spectroscopy of the cerebral cortex in rats.  

PubMed

A method for obtaining nuclear magnetic resonance (NMR) spectroscopic signals confined to the cerebral cortex in rat using a cortical coil constructed based on the principles of the zig-zag coil is described. We obtained 31P NMR spectra of normal cerebral cortex and cold-induced injured cortex using this cortical coil. The cortical coil clearly demonstrated an increase in inorganic phosphate (Pi) confirmed to cerebral cortex which, by contrast, the conventional planar surface coil failed to detect. There are significant metabolic differences between cortex and subcortical tissues. The technique described here, capable of assessing cortical metabolism in vivo without contamination by the underlying tissue, has substantial application to studies of cerebral metabolism. PMID:2628684

Houkin, K; Nakada, T; Suzuki, N; Kwee, I L

1989-12-01

419

Competition and representation during memory retrieval: Roles of the prefrontal cortex and the posterior parietal cortex  

PubMed Central

In this functional-MRI study we examined the hypothesis that the prefrontal cortex responds differently to the extent of competition during retrieval, whereas the parietal cortex is responsible for problem representation that should not be directly related to the competition. Participants mastered arbitrary person–location pairs, and their recognition memory was tested in a functional-MRI session. The pairs were constructed such that a person was associated with one, two, or three different locations and vice versa. The recognition time increased with the number of associations, reflecting increased competition. A confirmatory analysis of imaging data with prespecified prefrontal and parietal regions showed that, although both regions were highly involved during memory retrieval, only the prefrontal region responded to the levels of competition. This result was consistent with predictions of an information-processing model as well as with an exploratory identification of regions of interest. PMID:12773617

Sohn, Myeong-Ho; Goode, Adam; Stenger, V. Andrew; Carter, Cameron S.; Anderson, John R.

2003-01-01

420

Co-release of noradrenaline and dopamine in the cerebral cortex elicited by single train and repeated train stimulation of the locus coeruleus  

PubMed Central

Background Previous studies by our group suggest that extracellular dopamine (DA) and noradrenaline (NA) may be co-released from noradrenergic nerve terminals in the cerebral cortex. We recently demonstrated that the concomitant release of DA and NA could be elicited in the cerebral cortex by electrical stimulation of the locus coeruleus (LC). This study analyses the effect of both single train and repeated electrical stimulation of LC on NA and DA release in the medial prefrontal cortex (mPFC), occipital cortex (Occ), and caudate nucleus. To rule out possible stressful effects of electrical stimulation, experiments were performed on chloral hydrate anaesthetised rats. Results Twenty min electrical stimulation of the LC, with burst type pattern of pulses, increased NA and DA both in the mPFC and in the Occ. NA in both cortices and DA in the mPFC returned to baseline within 20 min after the end of the stimulation period, while DA in the Occ reached a maximum increase during 20 min post-stimulation and remained higher than baseline values at 220 min post-stimulation. Local perfusion with tetrodotoxin (TTX, 10 ?M) markedly reduced baseline NA and DA in the mPFC and Occ and totally suppressed the effect of electrical stimulation in both areas. A sequence of five 20 min stimulations at 20 min intervals were delivered to the LC. Each stimulus increased NA to the same extent and duration as the first stimulus, whereas DA remained elevated at the time next stimulus was delivered, so that baseline DA progressively increased in the mPFC and Occ to reach about 130 and 200% the initial level, respectively. In the presence of the NA transport (NAT) blocker desipramine (DMI, 100 ?M), multiple LC stimulation still increased extracellular NA and DA levels. Electrical stimulation of the LC increased NA levels in the homolateral caudate nucleus, but failed to modify DA level. Conclusion The results confirm and extend that LC stimulation induces a concomitant release of DA and NA in the mPFC and Occ. The different time-course of LC-induced elevation of DA and NA suggests that their co-release may be differentially controlled. PMID:15865626

Devoto, Paola; Flore, Giovanna; Saba, Pierluigi; Fà, Mauro; Gessa, Gian Luigi

2005-01-01

421

Primary motor cortex isolation: complete paralysis with preserved primary motor cortex  

Microsoft Academic Search

We present a left-sided hemiplegic patient with a cerebrovascular lesion involving the medial part of the right frontal and parietal lobes and the corpus callosum, but sparing the hand area of right primary motor cortex (M1). Several studies using transcranial magnetic stimulation demonstrated functional integrity of the efferent pathways from the right M1, intact sensory afferents to M1, an impairment

Katsuyuki Sakai; Emiko Kojima; Masahiko Suzuki; Yoshikazu Ugawa; Yasuo Terao; Ritsuko Hanajima; Ichiro Kanazawa

1998-01-01

422

A six year retrospective review of occipital nerve stimulation practice - controversies and challenges of an emerging technique for treating refractory headache syndromes  

PubMed Central

Background A retrospective review of patients treated with Occipital Nerve Stimulation (ONS) at two large tertiary referral centres has been audited in order to optimise future treatment pathways. Methods Patient’s medical records were retrospectively reviewed, and each patient was contacted by a trained headache expert to confirm clinical diagnosis and system efficacy. Results were compared to reported outcomes in current literature on ONS for primary headaches. Results Twenty-five patients underwent a trial of ONS between January 2007 and December 2012, and 23 patients went on to have permanent implantation of ONS. All 23 patients reached one-year follow/up, and 14 of them (61%) exceeded two years of follow-up. Seventeen of the 23 had refractory chronic migraine (rCM), and 3 refractory occipital neuralgia (ON). 11 of the 19 rCM patients had been referred with an incorrect headache diagnosis. Nine of the rCM patients (53%) reported 50% or more reduction in headache pain intensity and or frequency at long term follow-up (11–77 months). All 3 ON patients reported more than 50% reduction in pain intensity and/or frequency at 28–31 months. Ten (43%) subjects underwent surgical revision after an average of 11 ± 7 months from permanent implantation - in 90% of cases due to lead problems. Seven patients attended a specifically designed, multi-disciplinary, two-week pre-implant programme and showed improved scores across all measured psychological and functional parameters independent of response to subsequent ONS. Conclusions Our retrospective review: 1) confirms the long-term ONS success rate in refractory chronic headaches, consistent with previously published studies; 2) suggests that some headaches types may respond better to ONS than others (ON vs CM); 3) calls into question the role of trial stimulation in ONS; 4) confirms the high rate of complications related to the equipment not originally designed for ONS; 5) emphasises the need for specialist multidisciplinary care in these patients. PMID:23919570

2013-01-01

423

Diffeomorphic Sulcal Shape Analysis on the Cortex  

PubMed Central

We present a diffeomorphic approach for constructing intrinsic shape atlases of sulci on the human cortex. Sulci are represented as square-root velocity functions of continuous open curves in ?3, and their shapes are studied as functional representations of an infinite-dimensional sphere. This spherical manifold has some advantageous properties – it is equipped with a Riemannian metric on the tangent space and facilitates computational analyses and correspondences between sulcal shapes. Sulcal shape mapping is achieved by computing geodesics in the quotient space of shapes modulo scales, translations, rigid rotations and reparameterizations. The resulting sulcal shape atlas preserves important local geometry inherently present in the sample population. The sulcal shape atlas is integrated in a cortical registration framework and exhibits better geometric matching compared to the conventional euclidean method. We demonstrate experimental results for sulcal shape mapping, cortical surface registration, and sulcal classification for two different surface extraction protocols for separate subject populations. PMID:22328177

Joshi, Shantanu H.; Cabeen, Ryan P.; Joshi, Anand A.; Sun, Bo; Dinov, Ivo; Narr, Katherine L.; Toga, Arthur W.; Woods, Roger P.

2014-01-01

424

Dynamic Neuroplasticity after Human Prefrontal Cortex Damage  

PubMed Central

Summary Memory and attention deficits are common after prefrontal cortex (PFC) damage, yet people generally recover some function over time. Recovery is thought to be dependent upon undamaged brain regions but the temporal dynamics underlying cognitive recovery are poorly understood. Here we provide evidence that the intact PFC compensates for damage in the lesioned PFC on a trial-by-trial basis dependent on cognitive load. The extent of this rapid functional compensation is indexed by transient increases in electrophysiological measures of attention and memory in the intact PFC, detectable within a second after stimulus presentation and only when the lesioned hemisphere is challenged. These observations provide evidence supporting a dynamic and flexible model of compensatory neural plasticity. PMID:21040843

Voytek, Bradley; Davis, Matar; Yago, Elena; Barceló, Francisco; Vogel, Edward K.; Knight, Robert T.

2010-01-01

425

Periodicity and Evoked Responses in Motor Cortex  

PubMed Central

Spiking in primary motor cortex (MI) exhibits a characteristic ?-frequency periodicity, but the functional relevance of this rhythmic firing is controversial. We simultaneously recorded multiple single units and local field potentials (LFPs) in MI in two monkeys (Macaca Mulatta) during continuous, self-paced movements to serially presented targets. We find that the appearance of each new target evokes precisely-timed spiking in MI at a characteristic latency, but that the exact timing of this response varies depending on its relationship to the phase of the ongoing ?-range oscillation. As a result of this interaction between evoked spiking and endogenous ? periodicity, we find that the amount of information about target location encoded in the spiking of MI neurons is not simply a function of elapsed time, but depends also on oscillatory phase. Our results suggest that periodicity may be an important feature of the early stages of sensorimotor processing in the cortical motor system. PMID:20739573

Reimer, Jacob; Hatsopoulos, Nicholas G.

2010-01-01

426

Perceptual learning in the developing auditory cortex.  

PubMed

A hallmark of the developing auditory cortex is the heightened plasticity in the critical period, during which acoustic inputs can indelibly alter cortical function. However, not all sounds in the natural acoustic environment are ethologically relevant. How does the auditory system resolve relevant sounds from the acoustic environment in such an early developmental stage when most associative learning mechanisms are not yet fully functional? What can the auditory system learn from one of the most important classes of sounds, animal vocalizations? How does naturalistic acoustic experience shape cortical sound representation and perception? To answer these questions, we need to consider an unusual strategy, statistical learning, where what the system needs to learn is embedded in the sensory input. Here, I will review recent findings on how certain statistical structures of natural animal vocalizations shape auditory cortical acoustic representations, and how cortical plasticity may underlie learned categorical sound perception. These results will be discussed in the context of human speech perception. PMID:25728188

Bao, Shaowen

2015-03-01

427

Diffeomorphic sulcal shape analysis on the cortex.  

PubMed

We present a diffeomorphic approach for constructing intrinsic shape atlases of sulci on the human cortex. Sulci are represented as square-root velocity functions of continuous open curves in R³, and their shapes are studied as functional representations of an infinite-dimensional sphere. Th