Science.gov

Sample records for abnormal visual input

  1. Abnormal visual experience during development alters the early stages of visual-tactile integration.

    PubMed

    Niechwiej-Szwedo, Ewa; Chin, Jessica; Wolfe, Paul J; Popovich, Christina; Staines, W Richard

    2016-05-01

    Visual experience during the critical periods in early postnatal life is necessary for the normal development of the visual system. Disruption of visual input during this period results in amblyopia, which is associated with reduced activation of the striate and extrastriate cortices. It is well known that visual input converges with other sensory signals and exerts a significant influence on cortical processing in multiple association areas. Recent work in healthy adults has also shown that task-relevant visual input can modulate neural excitability at very early stages of information processing in the primary somatosensory cortex. Here we used electroencephalography to investigate visual-tactile interactions in adults with abnormal binocular vision due to amblyopia and strabismus. Results showed three main findings. First, in comparison to a visually normal control group, participants with abnormal vision had a significantly lower amplitude of the P50 somatosensory event related potential (ERP) when visual and tactile stimuli were presented concurrently. Second, the amplitude of the P100 somatosensory ERP was significantly greater in participants with abnormal vision. These results indicate that task relevant visual input does not significantly influence the excitability of the primary somatosensory cortex, instead, the excitability of the secondary somatosensory cortex is increased. Third, participants with abnormal vision had a higher amplitude of the P1 visual ERP when a tactile stimulus was presented concurrently. Importantly, these results were not modulated by viewing condition, which indicates that the impact of amblyopia on crossmodal interactions is not simply related to the reduced visual acuity as it was evident when viewing with the unaffected eye and binocularly. These results indicate that the consequences of abnormal visual experience on neurophysiological processing extend beyond the primary and secondary visual areas to other modality

  2. The Comparison of Visual Working Memory Representations with Perceptual Inputs

    ERIC Educational Resources Information Center

    Hyun, Joo-seok; Woodman, Geoffrey F.; Vogel, Edward K.; Hollingworth, Andrew; Luck, Steven J.

    2009-01-01

    The human visual system can notice differences between memories of previous visual inputs and perceptions of new visual inputs, but the comparison process that detects these differences has not been well characterized. In this study, the authors tested the hypothesis that differences between the memory of a stimulus array and the perception of a…

  3. On the Nature of Input Channels in Visual Processing

    ERIC Educational Resources Information Center

    Bjork, Elizabeth Ligon; Murray, J. Thomas

    1977-01-01

    This research assesses whether the presence of noise elements in a visual display affects the detection of target letters at the perceptual or feature extraction level of information processing and whether (a) input or processing channels operate in an independent or interactive fashion and (b) how the spatial relation between signal and noise…

  4. Visual and Auditory Input in Second-Language Speech Processing

    ERIC Educational Resources Information Center

    Hardison, Debra M.

    2010-01-01

    The majority of studies in second-language (L2) speech processing have involved unimodal (i.e., auditory) input; however, in many instances, speech communication involves both visual and auditory sources of information. Some researchers have argued that multimodal speech is the primary mode of speech perception (e.g., Rosenblum 2005). Research on…

  5. Adaptation to sensory input tunes visual cortex to criticality

    NASA Astrophysics Data System (ADS)

    Shew, Woodrow L.; Clawson, Wesley P.; Pobst, Jeff; Karimipanah, Yahya; Wright, Nathaniel C.; Wessel, Ralf

    2015-08-01

    A long-standing hypothesis at the interface of physics and neuroscience is that neural networks self-organize to the critical point of a phase transition, thereby optimizing aspects of sensory information processing. This idea is partially supported by strong evidence for critical dynamics observed in the cerebral cortex, but the impact of sensory input on these dynamics is largely unknown. Thus, the foundations of this hypothesis--the self-organization process and how it manifests during strong sensory input--remain unstudied experimentally. Here we show in visual cortex and in a computational model that strong sensory input initially elicits cortical network dynamics that are not critical, but adaptive changes in the network rapidly tune the system to criticality. This conclusion is based on observations of multifaceted scaling laws predicted to occur at criticality. Our findings establish sensory adaptation as a self-organizing mechanism that maintains criticality in visual cortex during sensory information processing.

  6. Reversible visual evoked potential abnormalities in uremic children.

    PubMed

    Ethier, Audrey-Anne; Lippé, Sarah; Mérouani, Aicha; Lassonde, Maryse; Saint-Amour, Dave

    2012-06-01

    In this case study, two cystinosis-related uremic children were followed at the Department of Nephrology, University of Montreal Hospital Center Sainte-Justine. Pattern-reversal visual evoked potentials were recorded at two time points, during dialysis treatment (time 1) and after renal transplant (time 2). Data were compared with those obtained from a control group (n = 6). The P1 component was selected and analyzed as the electrophysiologic marker of interest. At time 1, P1 latency was delayed, and P1 amplitude was reduced compared with control subjects. Both responses fell within normal range after kidney transplantation. These results indicate that renal failure and dialysis are associated with abnormal visual evoked potentials in children with chronic renal failure, but such alterations of visual processing are reversible after kidney transplant. PMID:22633636

  7. Transdiagnostic psychiatric symptoms related to visual evoked potential abnormalities.

    PubMed

    Bedwell, Jeffrey S; Butler, Pamela D; Chan, Chi C; Trachik, Benjamin J

    2015-12-15

    Visual processing abnormalities have been reported across a range of psychotic and mood disorders, but are typically examined within a particular disorder. The current study used a novel transdiagnostic approach to examine diagnostic classes, clinician-rated current symptoms, and self-reported personality traits in relation to visual processing abnormalities. We examined transient visual-evoked potentials (VEPs) from 48 adults (56% female), representing a wide range of psychotic and mood disorders, as well as individuals with no history of psychiatric disorder. Stimuli were low contrast check arrays presented on green and red backgrounds. Pairwise comparisons between individuals with schizophrenia-spectrum disorders (SSD), chronic mood disorders (CMD), and nonpsychiatric controls (NC) revealed no overall differences for either P1 or N1 amplitude. However, there was a significant interaction with the color background in which the NC group showed a significant increase in P1 amplitude to the red, vs. green, background, while the SSD group showed no change. This was related to an increase in social anhedonia and general negative symptoms. Stepwise regressions across the entire sample revealed that individuals with greater apathy and/or eccentric behavior had a reduced P1 amplitude. These relationships provide clues for uncovering the underlying causal pathology for these transdiagnostic symptoms. PMID:26412383

  8. Abnormalities in the Visual Processing of Viewing Complex Visual Stimuli Amongst Individuals With Body Image Concern

    PubMed Central

    Duncum, A. J. F.; Atkins, K. J.; Beilharz, F. L.; Mundy, M. E.

    2016-01-01

    Individuals with body dysmorphic disorder (BDD) and clinically concerning body-image concern (BIC) appear to possess abnormalities in the way they perceive visual information in the form of a bias towards local visual processing. As inversion interrupts normal global processing, forcing individuals to process locally, an upright-inverted stimulus discrimination task was used to investigate this phenomenon. We examined whether individuals with nonclinical, yet high levels of BIC would show signs of this bias, in the form of reduced inversion effects (i.e., increased local processing). Furthermore, we assessed whether this bias appeared for general visual stimuli or specifically for appearance-related stimuli, such as faces and bodies. Participants with high-BIC (n = 25) and low-BIC (n = 30) performed a stimulus discrimination task with upright and inverted faces, scenes, objects, and bodies. Unexpectedly, the high-BIC group showed an increased inversion effect compared to the low-BIC group, indicating perceptual abnormalities may not be present as local processing biases, as originally thought. There was no significant difference in performance across stimulus types, signifying that any visual processing abnormalities may be general rather than appearance-based. This has important implications for whether visual processing abnormalities are predisposing factors for BDD or develop throughout the disorder. PMID:27152128

  9. Abnormalities in the Visual Processing of Viewing Complex Visual Stimuli Amongst Individuals With Body Image Concern.

    PubMed

    Duncum, A J F; Atkins, K J; Beilharz, F L; Mundy, M E

    2016-01-01

    Individuals with body dysmorphic disorder (BDD) and clinically concerning body-image concern (BIC) appear to possess abnormalities in the way they perceive visual information in the form of a bias towards local visual processing. As inversion interrupts normal global processing, forcing individuals to process locally, an upright-inverted stimulus discrimination task was used to investigate this phenomenon. We examined whether individuals with nonclinical, yet high levels of BIC would show signs of this bias, in the form of reduced inversion effects (i.e., increased local processing). Furthermore, we assessed whether this bias appeared for general visual stimuli or specifically for appearance-related stimuli, such as faces and bodies. Participants with high-BIC (n = 25) and low-BIC (n = 30) performed a stimulus discrimination task with upright and inverted faces, scenes, objects, and bodies. Unexpectedly, the high-BIC group showed an increased inversion effect compared to the low-BIC group, indicating perceptual abnormalities may not be present as local processing biases, as originally thought. There was no significant difference in performance across stimulus types, signifying that any visual processing abnormalities may be general rather than appearance-based. This has important implications for whether visual processing abnormalities are predisposing factors for BDD or develop throughout the disorder. PMID:27152128

  10. Altering Visual Perception Abnormalities: A Marker for Body Image Concern

    PubMed Central

    Duncum, Anna J. F.; Mundy, Matthew E.

    2016-01-01

    The body image concern (BIC) continuum ranges from a healthy and positive body image, to clinical diagnoses of abnormal body image, like body dysmorphic disorder (BDD). BDD and non-clinical, yet high-BIC participants have demonstrated a local visual processing bias, characterised by reduced inversion effects. To examine whether this bias is a potential marker of BDD, the visual processing of individuals across the entire BIC continuum was examined. Dysmorphic Concern Questionnaire (DCQ; quantified BIC) scores were expected to correlate with higher discrimination accuracy and faster reaction times of inverted stimuli, indicating reduced inversion effects (occurring due to increased local visual processing). Additionally, an induced global or local processing bias via Navon stimulus presentation was expected to alter these associations. Seventy-four participants completed the DCQ and upright-inverted face and body stimulus discrimination task. Moderate positive associations were revealed between DCQ scores and accuracy rates for inverted face and body stimuli, indicating a graded local bias accompanying increases in BIC. This relationship supports a local processing bias as a marker for BDD, which has significant assessment implications. Furthermore, a moderate negative relationship was found between DCQ score and inverted face accuracy after inducing global processing, indicating the processing bias can temporarily be reversed in high BIC individuals. Navon stimuli were successfully able to alter the visual processing of individuals across the BIC continuum, which has important implications for treating BDD. PMID:27003715

  11. Altering Visual Perception Abnormalities: A Marker for Body Image Concern.

    PubMed

    Beilharz, Francesca L; Atkins, Kelly J; Duncum, Anna J F; Mundy, Matthew E

    2016-01-01

    The body image concern (BIC) continuum ranges from a healthy and positive body image, to clinical diagnoses of abnormal body image, like body dysmorphic disorder (BDD). BDD and non-clinical, yet high-BIC participants have demonstrated a local visual processing bias, characterised by reduced inversion effects. To examine whether this bias is a potential marker of BDD, the visual processing of individuals across the entire BIC continuum was examined. Dysmorphic Concern Questionnaire (DCQ; quantified BIC) scores were expected to correlate with higher discrimination accuracy and faster reaction times of inverted stimuli, indicating reduced inversion effects (occurring due to increased local visual processing). Additionally, an induced global or local processing bias via Navon stimulus presentation was expected to alter these associations. Seventy-four participants completed the DCQ and upright-inverted face and body stimulus discrimination task. Moderate positive associations were revealed between DCQ scores and accuracy rates for inverted face and body stimuli, indicating a graded local bias accompanying increases in BIC. This relationship supports a local processing bias as a marker for BDD, which has significant assessment implications. Furthermore, a moderate negative relationship was found between DCQ score and inverted face accuracy after inducing global processing, indicating the processing bias can temporarily be reversed in high BIC individuals. Navon stimuli were successfully able to alter the visual processing of individuals across the BIC continuum, which has important implications for treating BDD. PMID:27003715

  12. Abnormalities in visual processing amongst students with body image concerns

    PubMed Central

    Mundy E., Matthew; Sadusky, Andrea

    2014-01-01

    Individuals with body dysmorphic disorder (BDD) appear to possess abnormalities in the way they observe and discriminate visual information. A pre-occupation with perceived defects in appearance has been attributed to a local visual processing bias. We studied the nature of visual bias in individuals who may be at risk of developing BDD – those with high body image concerns (BICs) – by using inverted stimulus discrimination. Inversion disrupts global, configural information in favor of local, feature-based processing. 40 individuals with high BIC and 40 low BIC controls performed a discrimination task with upright and inverted faces, bodies, and scenes. Individuals with high BIC discriminated inverted faces and bodies faster than controls, and were also more accurate when discriminating inverted bodies and scenes. This reduction in inversion effect for high BIC individuals may be due to a stimulus-general local, detail-focused processing bias, which may be associated with maladaptive fixation on small features in their appearance. PMID:25157299

  13. Neural correlates for task-relevant facilitation of visual inputs during visually-guided hand movements.

    PubMed

    Lebar, Nicolas; Bernier, Pierre-Michel; Guillaume, Alain; Mouchnino, Laurence; Blouin, Jean

    2015-11-01

    Vision is a powerful source of information for controlling movements, especially fine actions produced by the hand that require a great deal of accuracy. However, the neural processes that enable vision to enhance movement accuracy are not well understood. In the present study, we tested the hypothesis that the cortical sensitivity to visual inputs increases during a spatially-constrained hand movement compared to a situation where visual information is irrelevant to the task. Specifically, we compared the cortical visual-evoked potentials (VEPs) in response to flashes (right visual hemifield) recorded while participants followed the outline of an irregular polygon with a pen (i.e., tracing), with VEPs recorded when participants simply kept the pen still. This tracing task was chosen specifically because it requires many different visual processes (e.g., detection of line orientation, motion perception, visuomotor transformation) to be completed successfully. The tracing and resting tasks were performed with normal vision and also with mirror-reversed vision, thereby increasing task difficulty when tracing. We predicted that the sensitivity to visual inputs would be enhanced (i.e. greater VEPs) during tracing and that this increase in response sensitivity would be greater when tracing was performed with mirror-reversed vision. In addition, in order to investigate the existence of a link between the sensitivity to visual inputs and the accuracy with which participants traced the shape, we assigned participants to high performer (HP) or low performer (LP) groups according to their tracing performance in the condition with mirror-reversed visual feedback. Source analyses revealed that, for both groups, the sensitivity to visual inputs of the left occipital and MT/MST regions increased when participants traced the shape as compared to when they were resting. Also, for both groups of participants, the mirror-reversed vision did not affect the amplitude of the cortical

  14. Asymmetric visual input and route recapitulation in homing pigeons

    PubMed Central

    Martinho, Antone; Biro, Dora; Guilford, Tim; Gagliardo, Anna; Kacelnik, Alex

    2015-01-01

    Pigeons (Columba livia) display reliable homing behaviour, but their homing routes from familiar release points are individually idiosyncratic and tightly recapitulated, suggesting that learning plays a role in route establishment. In light of the fact that routes are learned, and that both ascending and descending visual pathways share visual inputs from each eye asymmetrically to the brain hemispheres, we investigated how information from each eye contributes to route establishment, and how information input is shared between left and right neural systems. Using on-board global positioning system loggers, we tested 12 pigeons' route fidelity when switching from learning a route with one eye to homing with the other, and back, in an A-B-A design. Two groups of birds, trained first with the left or first with the right eye, formed new idiosyncratic routes after switching eyes, but those that flew first with the left eye formed these routes nearer to their original routes. This confirms that vision plays a major role in homing from familiar sites and exposes a behavioural consequence of neuroanatomical asymmetry whose ontogeny is better understood than its functional significance. PMID:26446810

  15. Asymmetric visual input and route recapitulation in homing pigeons.

    PubMed

    Martinho, Antone; Biro, Dora; Guilford, Tim; Gagliardo, Anna; Kacelnik, Alex

    2015-10-01

    Pigeons (Columba livia) display reliable homing behaviour, but their homing routes from familiar release points are individually idiosyncratic and tightly recapitulated, suggesting that learning plays a role in route establishment. In light of the fact that routes are learned, and that both ascending and descending visual pathways share visual inputs from each eye asymmetrically to the brain hemispheres, we investigated how information from each eye contributes to route establishment, and how information input is shared between left and right neural systems. Using on-board global positioning system loggers, we tested 12 pigeons' route fidelity when switching from learning a route with one eye to homing with the other, and back, in an A-B-A design. Two groups of birds, trained first with the left or first with the right eye, formed new idiosyncratic routes after switching eyes, but those that flew first with the left eye formed these routes nearer to their original routes. This confirms that vision plays a major role in homing from familiar sites and exposes a behavioural consequence of neuroanatomical asymmetry whose ontogeny is better understood than its functional significance. PMID:26446810

  16. Mathematical impairment associated with high-contrast abnormalities in change detection and magnocellular visual evoked response.

    PubMed

    Jastrzebski, Nicola R; Crewther, Sheila G; Crewther, David P

    2015-10-01

    The cause of developmental dyscalculia, a specific deficit in acquisition of arithmetic skills, particularly of enumeration, has never been investigated with respect to the patency of the visual magnocellular system. Here, the question of dysfunction of the afferent magnocellular cortical input and its dorsal stream projections was tested directly using nonlinear analysis of the visual evoked potential (VEP) and through the psychophysical ability to rapidly detect visual change. A group of young adults with self-reported deficiencies of arithmetical ability, showed marked impairment in magnitude estimation and enumeration performance-though not in lexical decision reaction times when compared with an arithmetically capable group controlled for age and handedness. Multifocal nonlinear VEPs were recorded at low (24 %) and high (96 %) contrast. First- and second-order VEP kernels were comparable between groups at low contrast, but not at high contrast. The mathematically impaired group showed an abnormal lack of contrast saturation in the shortest latency first-order peak (N60) and a delayed P100 positivity in the first slice of the second-order kernel. Both features have previously been argued to be physiological markers of magnocellular function. Mathematically impaired participants also performed worse on a gap paradigm change detection for digit task showing increased reaction times for high-contrast stimuli but not for low-contrast stimuli compared with controls. The VEP results give direct evidence of abnormality in the occipital processing of magnocellular information in those with mathematical impairment. The anomalous high visual contrast physiological and psychophysical performance suggests an abnormality in the inhibitory processes that normally result in saturation of contrast gain in the magnocellular system. PMID:26195163

  17. Abnormal access of axial vibrotactile input to deafferented somatosensory cortex in human upper limb amputees.

    PubMed

    Kew, J J; Halligan, P W; Marshall, J C; Passingham, R E; Rothwell, J C; Ridding, M C; Marsden, C D; Brooks, D J

    1997-05-01

    We studied two human subjects with total deafferentation of one upper limb secondary to traumatic multiple cervical root avulsions. Both subjects developed a phantom limb and underwent elective amputation of the paralyzed, deafferentated limb. Psychophysical study revealed in each subject an area of skin in the pectoral region ipsilateral to the amputation where vibrotactile stimulation (VS) elicited referred sensations (RS) in the phantom limb. Positron emission tomography was then used to measure regional cerebral blood flow changes during VS of the pectoral region ipsilateral to the amputation with RS and during VS of a homologous part of the pectoral region adjacent to the intact arm without RS. A voxel-based correlation analysis was subsequently used to study functional connectivity. VS of the pectoral region adjacent to the intact arm was associated with activation of the dorsal part of the contralateral primary somatosensory cortex (S1) in a position consistent with the S1 trunk area. In contrast, VS of the pectoral region ipsilateral to the amputation with RS was associated with activation of the contralateral S1 that extended from the level of the trunk representation ventrally over distances of 20 and 12 mm, respectively, in the two subjects. The area of S1 activated during VS of the digits in a normal control subject was coextensive with the ventral S1 region abnormally activated during VS of the ectopic phantom representation in the two amputees, suggesting that the deafferented digit or hand/arm area had been activated by sensory input from the pectoral region. Correlation analysis showed an abnormal pattern of intrinsic connectivity within the deafferented S1 hand/arm area of both amputees. In one subject, the deafferented S1 was functionally connected with 3 times as many S1 voxels as the normally afferented S1. This abnormal functional connectivity extended in both the rostrocaudal and ventrodorsal dimensions. The results demonstrate that sensory

  18. Visualizing how cancer chromosome abnormalities form in living cells

    Cancer.gov

    For the first time, scientists have directly observed events that lead to the formation of a chromosome abnormality that is often found in cancer cells. The abnormality, called a translocation, occurs when part of a chromosome breaks off and becomes attac

  19. Visual input signaling threat gains preferential access to awareness in a breaking continuous flash suppression paradigm.

    PubMed

    Gayet, Surya; Paffen, Chris L E; Belopolsky, Artem V; Theeuwes, Jan; Van der Stigchel, Stefan

    2016-04-01

    Visual input that signals threat is inherently relevant for survival. Accordingly, it has been demonstrated that threatening visual input elicits faster behavioral responses than non-threatening visual input. Considering that awareness is a prerequisite for performing demanding tasks and guiding novel behavior, we hypothesized that threatening visual input would gain faster access to awareness than non-threatening visual input. In the present study, we associated one of two basic visual stimuli, that were devoid of intrinsic relevance (colored annuli), with aversive stimulation (i.e., electric shocks) following a classical fear conditioning procedure. In the subsequent test phase no more electric shocks were delivered, and a breaking continuous flash suppression task was used to measure how fast these stimuli would access awareness. The results reveal that stimuli that were previously paired with an electric shock break through suppression faster than comparable stimuli that were not paired with an electric shock. PMID:26807500

  20. Frequency-Band Signatures of Visual Responses to Naturalistic Input in Ferret Primary Visual Cortex during Free Viewing

    PubMed Central

    Sellers, Kristin K.; Bennett, Davis V.; Frohlich, Flavio

    2015-01-01

    Neuronal firing responses reflect the statistics of visual input and emerge from the interaction with endogenous network dynamics. Artificial visual stimuli presented to animals in which the network dynamics were constrained by anesthetic agents or trained behavioral tasks have provided fundamental understanding of how individual neurons in primary visual cortex respond to input. In contrast, very little is known about the mesoscale network dynamics and their relationship to microscopic spiking activity in the awake animal during free viewing of naturalistic visual input. To address this gap in knowledge, we recorded local field potential (LFP) and multiunit activity (MUA) in all layers of primary visual cortex (V1) of awake, freely viewing ferrets presented with naturalistic visual input (nature movie clips). We found that naturalistic visual stimuli modulated the entire oscillation spectrum; low frequency oscillations were mostly suppressed whereas higher frequency oscillations were enhanced. In average across all cortical layers, stimulus-induced change in delta and alpha power negatively correlated with the MUA responses, whereas sensory-evoked increases in gamma power positively correlated with MUA responses. The time-course of the band-limited power in these frequency bands provided evidence for a model in which naturalistic visual input switched V1 between two distinct, endogenously present activity states defined by the power of low (delta, alpha) and high (gamma) frequency oscillatory activity. Therefore, the two mesoscale activity states delineated in this study may define the engagement of the circuit with processing sensory input at the level of spiking activity. PMID:25498982

  1. Visual display panel functions as computer input/output device

    NASA Technical Reports Server (NTRS)

    Hilborn, E. H.

    1970-01-01

    Display panel permits information entry and erasure using a probe, and has an inherent storage capability for use on time-shared systems. Data input need not be online. Other advantages include direct display of input and output, simplicity, and low fabrication cost.

  2. Visual Learning: Creative Input for the Handicapped Learner.

    ERIC Educational Resources Information Center

    Rogers, Linda

    A teacher of learning disabled secondary students discusses the role of visual learning in motivating students and increasing their communication skills. Application of visual methods in an American and British setting is seen to have resulted in gains in self concept, motivation toward school, and in comunication skills. (CL)

  3. Handwriting generates variable visual input to facilitate symbol learning

    PubMed Central

    Li, Julia X.; James, Karin H.

    2015-01-01

    Recent research has demonstrated that handwriting practice facilitates letter categorization in young children. The present experiments investigated why handwriting practice facilitates visual categorization by comparing two hypotheses: That handwriting exerts its facilitative effect because of the visual-motor production of forms, resulting in a direct link between motor and perceptual systems, or because handwriting produces variable visual instances of a named category in the environment that then changes neural systems. We addressed these issues by measuring performance of 5 year-old children on a categorization task involving novel, Greek symbols across 6 different types of learning conditions: three involving visual-motor practice (copying typed symbols independently, tracing typed symbols, tracing handwritten symbols) and three involving visual-auditory practice (seeing and saying typed symbols of a single typed font, of variable typed fonts, and of handwritten examples). We could therefore compare visual-motor production with visual perception both of variable and similar forms. Comparisons across the six conditions (N=72) demonstrated that all conditions that involved studying highly variable instances of a symbol facilitated symbol categorization relative to conditions where similar instances of a symbol were learned, regardless of visual-motor production. Therefore, learning perceptually variable instances of a category enhanced performance, suggesting that handwriting facilitates symbol understanding by virtue of its environmental output: supporting the notion of developmental change though brain-body-environment interactions. PMID:26726913

  4. Abnormal visual gain control in a Parkinson's disease model

    PubMed Central

    Afsari, Farinaz; Christensen, Kenneth V.; Smith, Garrick Paul; Hentzer, Morten; Nippe, Olivia M.; Elliott, Christopher J. H.; Wade, Alex R.

    2014-01-01

    Our understanding of Parkinson's disease (PD) has been revolutionized by the discovery of disease-causing genetic mutations. The most common of these is the G2019S mutation in the LRRK2 kinase gene, which leads to increased kinase activity. However, the link between increased kinase activity and PD is unclear. Previously, we showed that dopaminergic expression of the human LRRK2-G2019S transgene in flies led to an activity-dependent loss of vision in older animals and we hypothesized that this may have been preceded by a failure to regulate neuronal activity correctly in younger animals. To test this hypothesis, we used a sensitive measure of visual function based on frequency-tagged steady-state visually evoked potentials. Spectral analysis allowed us to identify signals from multiple levels of the fly visual system and wild-type visual response curves were qualitatively similar to those from human cortex. Dopaminergic expression of hLRRK2-G2019S increased contrast sensitivity throughout the retinal network. To test whether this was due to increased kinase activity, we fed Drosophila with kinase inhibitors targeted at LRRK2. Contrast sensitivity in both day 1 and day 14 flies was normalized by a novel LRRK2 kinase inhibitor ‘BMPPB-32’. Biochemical and cellular assays suggested that BMPPB-32 would be a more specific kinase inhibitor than LRRK2-IN-1. We confirmed this in vivo, finding that dLRRK− null flies show large off-target effects with LRRK2-IN-1 but not BMPPB-32. Our data link the increased Kinase activity of the G2019S-LRRK2 mutation to neuronal dysfunction and demonstrate the power of the Drosophila visual system in assaying the neurological effects of genetic diseases and therapies. PMID:24718285

  5. Retinal input instructs alignment of visual topographic maps

    PubMed Central

    Triplett, Jason W.; Owens, Melinda T.; Yamada, Jena; Lemke, Greg; Cang, Jianhua; Stryker, Michael P.; Feldheim, David A.

    2009-01-01

    SUMMARY Sensory information is represented in the brain in the form of topographic maps, in which neighboring neurons respond to adjacent external stimuli. In the visual system, the superior colliculus receives topographic projections from the retina and primary visual cortex (V1) that are aligned. Alignment may be achieved through the use of a gradient of shared axon guidance molecules, or through a retinal-matching mechanism in which axons that monitor identical regions of visual space align. To distinguish between these possibilities, we take advantage of genetically-engineered mice that we show have a duplicated functional retinocollicular map but only a single map in V1. Anatomical tracing revealed that the corticocollicular projection bifurcates to align with the duplicated retinocollicular map in a manner dependent on the normal pattern of spontaneous activity during development. These data suggest a general model in which convergent maps use coincident activity patterns to achieve alignment. PMID:19804762

  6. Abnormal visual field maps in human cortex: a mini-review and a case report.

    PubMed

    Haak, Koen V; Langers, Dave R M; Renken, Remco; van Dijk, Pim; Borgstein, Johannes; Cornelissen, Frans W

    2014-07-01

    Human visual cortex contains maps of the visual field. Much research has been dedicated to answering whether and when these visual field maps change if critical components of the visual circuitry are damaged. Here, we first provide a focused mini-review of the functional magnetic resonance imaging (fMRI) studies that have evaluated the human cortical visual field maps in the face of retinal lesions, brain injury, and atypical retinocortical projections. We find that there is a fair body of research that has found abnormal fMRI activity, but also that this abnormal activity does not necessarily stem from cortical remapping. The abnormal fMRI activity can often be explained in terms of task effects and/or the uncovering of normally hidden system dynamics. We then present the case of a 16-year-old patient who lost the entire left cerebral hemisphere at age three for treatment of chronic focal encephalitis (Rasmussen syndrome) and intractable epilepsy. Using an fMRI retinotopic mapping procedure and population receptive field (pRF) modeling, we found that (1) despite the long period since the hemispherectomy, the retinotopic organization of early visual cortex remained unaffected by the removal of an entire cerebral hemisphere, and (2) the intact lateral occipital cortex contained an exceptionally large representation of the center of the visual field. The same method also indicates that the neuronal receptive fields in these lateral occipital brain regions are extraordinarily small. These features are clearly abnormal, but again they do not necessarily stem from cortical remapping. For example, the abnormal features can also be explained by the notion that the hemispherectomy took place during a critical period in the development of the lateral occipital cortex and therefore arrested its normal development. Thus, caution should be exercised when interpreting abnormal fMRI activity as a marker of cortical remapping; there are often other explanations. PMID:23347557

  7. Automatic human action recognition in a scene from visual inputs

    NASA Astrophysics Data System (ADS)

    Bouma, Henri; Hanckmann, Patrick; Marck, Jan-Willem; Penning, Leo; den Hollander, Richard; ten Hove, Johan-Martijn; van den Broek, Sebastiaan; Schutte, Klamer; Burghouts, Gertjan

    2012-06-01

    Surveillance is normally performed by humans, since it requires visual intelligence. However, this can be dull and dangerous, especially for military operations. Therefore, unmanned autonomous visual-intelligence systems are desired. In this paper, we present a novel system that can recognize human actions, which are relevant to detect operationally significant activity. Central to the system is a break-down of high-level perceptual concepts (verbs) in simpler observable events. The system is trained on 3482 videos and evaluated on 2589 videos from the DARPA Mind's Eye program, with for each video human annotations indicating the presence or absence of 48 different actions. The results show that our system reaches good performance approaching the human average response.

  8. Abnormal late visual responses and alpha oscillations in neurofibromatosis type 1: a link to visual and attention deficits

    PubMed Central

    2014-01-01

    Background Neurofibromatosis type 1 (NF1) affects several areas of cognitive function including visual processing and attention. We investigated the neural mechanisms underlying the visual deficits of children and adolescents with NF1 by studying visual evoked potentials (VEPs) and brain oscillations during visual stimulation and rest periods. Methods Electroencephalogram/event-related potential (EEG/ERP) responses were measured during visual processing (NF1 n = 17; controls n = 19) and idle periods with eyes closed and eyes open (NF1 n = 12; controls n = 14). Visual stimulation was chosen to bias activation of the three detection mechanisms: achromatic, red-green and blue-yellow. Results We found significant differences between the groups for late chromatic VEPs and a specific enhancement in the amplitude of the parieto-occipital alpha amplitude both during visual stimulation and idle periods. Alpha modulation and the negative influence of alpha oscillations in visual performance were found in both groups. Conclusions Our findings suggest abnormal later stages of visual processing and enhanced amplitude of alpha oscillations supporting the existence of deficits in basic sensory processing in NF1. Given the link between alpha oscillations, visual perception and attention, these results indicate a neural mechanism that might underlie the visual sensitivity deficits and increased lapses of attention observed in individuals with NF1. PMID:24559228

  9. Abnormal ventricular development in preterm neonates with visually normal MRIs

    NASA Astrophysics Data System (ADS)

    Shi, Jie; Wang, Yalin; Lao, Yi; Ceschin, Rafael; Mi, Liang; Nelson, Marvin D.; Panigrahy, Ashok; Leporé, Natasha

    2015-12-01

    Children born preterm are at risk for a wide range of neurocognitive and neurobehavioral disorders. Some of these may stem from early brain abnormalities at the neonatal age. Hence, a precise characterization of neonatal neuroanatomy may help inform treatment strategies. In particular, the ventricles are often enlarged in neurocognitive disorders, due to atrophy of surrounding tissues. Here we present a new pipeline for the detection of morphological and relative pose differences in the ventricles of premature neonates compared to controls. To this end, we use a new hyperbolic Ricci flow based mapping of the ventricular surfaces of each subjects to the Poincaré disk. Resulting surfaces are then registered to a template, and a between group comparison is performed using multivariate tensor-based morphometry. We also statistically compare the relative pose of the ventricles within the brain between the two groups, by performing a Procrustes alignment between each subject's ventricles and an average shape. For both types of analyses, differences were found in the left ventricles between the two groups.

  10. Mathematically-Relevant Input during Play of a Caregiver with a Visual Impairment and Her Toddler

    ERIC Educational Resources Information Center

    Lee, Joanne; Kotsopoulos, Donna; Stordy, Caryl-Anne

    2012-01-01

    This research investigated play between two caregivers, one with a visual impairment, and their 15-month-old daughter. The mother has a visual impairment. We aimed to identify the similarities and differences in mathematically-relevant input by comparing the 30-min naturalistic play session conducted separately between the mother-daughter and the…

  11. Speaking Math--A Voice Input, Speech Output Calculator for Students with Visual Impairments

    ERIC Educational Resources Information Center

    Bouck, Emily C.; Flanagan, Sara; Joshi, Gauri S.; Sheikh, Waseem; Schleppenbach, Dave

    2011-01-01

    This project explored a newly developed computer-based voice input, speech output (VISO) calculator. Three high school students with visual impairments educated at a state school for the blind and visually impaired participated in the study. The time they took to complete assessments and the average number of attempts per problem were recorded…

  12. Sudden insight is associated with shutting out visual inputs.

    PubMed

    Salvi, Carola; Bricolo, Emanuela; Franconeri, Steven L; Kounios, John; Beeman, Mark

    2015-12-01

    Creative ideas seem often to appear when we close our eyes, stare at a blank wall, or gaze out of a window--all signs of shutting out distractions and turning attention inward. Prior research has demonstrated that attention-related brain areas are differently active when people solve problems with sudden insight (the Aha! phenomenon), relative to deliberate, analytic solving. We directly investigated the relationship between attention deployment and problem solving by recording eye movements and blinks, which are overt indicators of attention, as people solved short, visually presented problems. In the preparation period, before problems eventually solved by insight, participants blinked more frequently and longer, and made fewer fixations, than before problems eventually solved by analysis. Immediately prior to solutions, participants blinked longer and looked away from the problem more often when solving by insight than when solving analytically. These phenomena extend prior research with a direct demonstration of dynamic differences in attention as people solve problems with sudden insight versus analytically. PMID:26268431

  13. Visual stimulation switches the polarity of excitatory input to starburst amacrine cells

    PubMed Central

    Vlasits, Anna L.; Bos, Rémi; Morrie, Ryan D.; Fortuny, Cécile; Flannery, John G.; Feller, Marla B.; Rivlin-Etzion, Michal

    2014-01-01

    Summary Direction-selective ganglion cells (DSGCs) are tuned to motion in one direction. Starburst amacrine cells (SACs) are thought to mediate this direction selectivity through precise anatomical wiring to DSGCs. Nevertheless, we previously found that visual adaptation can reverse DSGCs’ directional tuning, overcoming the circuit anatomy. Here we explore the role of SACs in the generation and adaptation of direction selectivity. First, using pharmaco-genetics and two-photon calcium imaging, we validate that SACs are necessary for direction selectivity. Next, we demonstrate that exposure to an adaptive stimulus dramatically alters SACs’ synaptic inputs. Specifically, after visual adaptation, On-SACs lose their excitatory input during light onset but gain an excitatory input during light offset. Our data suggest that visual stimulation alters the interactions between rod and cone-mediated inputs that converge on the terminals of On cone BCs. These results demonstrate how the sensory environment can modify computations performed by anatomically-defined neuronal circuits. PMID:25155960

  14. Anorexia Nervosa and Body Dysmorphic Disorder are Associated with Abnormalities in Processing Visual Information

    PubMed Central

    Li, Wei; Lai, Tsz Man; Bohon, Cara; Loo, Sandra K; McCurdy, Danyale; Strober, Michael; Bookheimer, Susan; Feusner, Jamie

    2016-01-01

    Background Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted body image and are frequently comorbid with each other, although their relationship remains little studied. While there is evidence of abnormalities in visual and visuospatial processing in both disorders, no study has directly compared the two. We used two complementary modalities – event-related potentials (ERP) and fMRI – to test for abnormal activity associated with early visual signaling. Methods We acquired fMRI and ERP data in separate sessions from 15 unmedicated individuals in each of three groups (weight-restored AN, BDD, and healthy controls) while they viewed images of faces and houses of different spatial frequencies. We used joint independent component analyses to compare activity in visual systems. Results AN and BDD groups demonstrated similar hypoactivity in early secondary visual processing regions and the dorsal visual stream when viewing low spatial frequency faces, linked to the N170 component, as well as in early secondary visual processing regions when viewing low spatial frequency houses, linked to the P100 component. Additionally, the BDD group exhibited hyperactivity in fusiform cortex when viewing high spatial frequency houses, linked to the N170 component. Greater activity in this component was associated with lower attractiveness ratings of faces. Conclusions Results provide preliminary evidence of similar abnormal spatio-temporal activation in AN and BDD for configural/holistic information for appearance- and nonappearance-related stimuli. This suggests a common phenotype of abnormal early visual system functioning, which may contribute to perceptual distortions. PMID:25652023

  15. Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs

    PubMed Central

    Mahoney, Jeannette R.; Molholm, Sophie; Butler, John S.; Sehatpour, Pejman; Gomez-Ramirez, Manuel; Ritter, Walter; Foxe, John J.

    2015-01-01

    Correlated sensory inputs coursing along the individual sensory processing hierarchies arrive at multisensory convergence zones in cortex where inputs are processed in an integrative manner. The exact hierarchical level of multisensory convergence zones and the timing of their inputs are still under debate, although increasingly, evidence points to multisensory integration (MSI) at very early sensory processing levels. While MSI is said to be governed by stimulus properties including space, time, and magnitude, violations of these rules have been documented. The objective of the current study was to determine, both psychophysically and electrophysiologically, whether differential visual-somatosensory (VS) integration patterns exist for stimuli presented to the same versus opposite hemifields. Using high-density electrical mapping and complementary psychophysical data, we examined multisensory integrative processing for combinations of visual and somatosensory inputs presented to both left and right spatial locations. We assessed how early during sensory processing VS interactions were seen in the event-related potential and whether spatial alignment of the visual and somatosensory elements resulted in differential integration effects. Reaction times to all VS pairings were significantly faster than those to the unisensory conditions, regardless of spatial alignment, pointing to engagement of integrative multisensory processing in all conditions. In support, electrophysiological results revealed significant differences between multisensory simultaneous VS and summed V + S responses, regardless of the spatial alignment of the constituent inputs. Nonetheless, multisensory effects were earlier in the aligned conditions, and were found to be particularly robust in the case of right-sided inputs (beginning at just 55 ms). In contrast to previous work on audio-visual and audio-somatosensory inputs, the current work suggests a degree of spatial specificity to the earliest

  16. Layer-Specific Input to Distinct Cell Types in Layer 6 of Monkey Primary Visual Cortex

    PubMed Central

    Briggs, Farran; Callaway, Edward M.

    2007-01-01

    Layer 6 of monkey V1 contains a physiologically and anatomically diverse population of excitatory pyramidal neurons. Distinctive arborization patterns of axons and dendrites within the functionally specialized cortical layers define eight types of layer 6 pyramidal neurons and suggest unique information processing roles for each cell type. To address how input sources contribute to cellular function, we examined the laminar sources of functional excitatory input onto individual layer 6 pyramidal neurons using scanning laser photostimulation. We find that excitatory input sources correlate with cell type. Class I neurons with axonal arbors selectively targeting magnocellular (M) recipient layer 4Cα receive input from M-dominated layer 4B, whereas class I neurons whose axonal arbors target parvocellular (P) recipient layer 4Cβ receive input from P-dominated layer 2/3. Surprisingly, these neuronal types do not differ significantly in the inputs they receive directly from layers 4Cα or 4Cβ. Class II cells, which lack dense axonal arbors within layer 4C, receive excitatory input from layers targeted by their local axons. Specifically, type IIA cells project axons to and receive input from the deep but not superficial layers. Type IIB neurons project to and receive input from the deepest and most superficial, but not middle layers. Type IIC neurons arborize throughout the cortical layers and tend to receive inputs from all cortical layers. These observations have implications for the functional roles of different layer 6 cell types in visual information processing. PMID:11331389

  17. Visual repetition priming for words relies on access to the visual input lexicon: evidence from a dyslexic patient.

    PubMed

    Carlesimo, G A; Fadda, L; Sabbadini, M; Caltagirone, C

    1994-09-01

    In this study we tested the hypothesis that visual repetition priming for words depends upon the accessibility of lexical units in the visual input lexicon. For this purpose, we investigated a dyslexic patient, A.M., whose neuropsychological performances suggested an impaired access to the lexical route of reading. According to the predictions, Experiments 1 and 2 demonstrated deficient priming in tests involving the visual presentation of words (Word Identification and Stem Completion). In Experiment 3, we demonstrated that A.M.'s deficient priming was specific for visually presented words, in that the auditory presentation elicited a normal priming effect (auditory Stem Completion). These data are discussed in the light of a theoretical framework suggesting a fractionation of the modalities by which repetition priming can be elicited, each mediated by a particular memory subsystem. PMID:7991076

  18. Higher order visual input to the mushroom bodies in the bee, Bombus impatiens

    PubMed Central

    Paulk, Angelique C.; Gronenberg, Wulfila

    2008-01-01

    To produce appropriate behaviors based on biologically relevant associations, sensory pathways conveying different modalities are integrated by higher-order central brain structures, such as insect mushroom bodies. To address this function of sensory integration, we characterized the structure and response of optic lobe neurons projecting to the calyces of the mushroom bodies in bees. Bees are well known for their visual learning and memory capabilities and their brains possess major direct visual input from the optic lobes to the mushroom bodies. To functionally characterize these visual inputs to the mushroom bodies, we recorded intracellularly from neurons in bumblebees (Apidae: Bombus impatiens) and a single neuron in a honeybee (Apidae: Apis mellifera) while presenting color and motion stimuli. All of the mushroom body input neurons were color sensitive while a subset was motion sensitive. Additionally, most of the mushroom body input neurons would respond to the first, but not to subsequent, presentations of repeated stimuli. In general, the medulla or lobula neurons projecting to the calyx signaled specific chromatic, temporal, and motion features of the visual world to the mushroom bodies, which included sensory information required for the biologically relevant associations bees form during foraging tasks. PMID:18635397

  19. Density of Visual Input Enhancement and Grammar Learning: A Research Proposal

    ERIC Educational Resources Information Center

    Tran, Thu Hoang

    2009-01-01

    Research in the field of second language acquisition (SLA) has been done to ascertain the effectiveness of visual input enhancement (VIE) on grammar learning. However, one issue remains unexplored: the effects of VIE density on grammar learning. This paper presents a research proposal to investigate the effects of the density of VIE on English…

  20. Student Preparation and the Power of Visual Input in Veterinary Surgical Education: An Empirical Study.

    PubMed

    Langebæk, Rikke; Nielsen, Søren Saxmose; Koch, Bodil Cathrine; Berendt, Mette

    2016-01-01

    In recent years, veterinary educational institutions have implemented alternative teaching methods, including video demonstrations of surgical procedures. However, the power of the dynamic visual input from videos in relation to recollection of a surgical procedure has never been evaluated. The aim of this study was to investigate how veterinary surgical students perceived the influence of different educational materials on recollection of a surgical procedure. Furthermore, we investigated if surgical technique was associated with a certain method of recollection or use of educational material. During a basic surgical skills course, 112 fourth-year veterinary students participated in the study by completing a questionnaire regarding method of recollection, influence of individual types of educational input, and homework preparation. Furthermore, we observed students performing an orchiectomy in a terminal pig lab. Preparation for the pig lab consisted of homework (textbook, online material, including videos), lecture, cadaver lab, and toy animal models in a skills lab. In the instructional video, a detail was used that was not described elsewhere. Results show that 60% of the students used a visual dynamic method as their main method of recollection and that video was considered the most influential educational input with respect to recollection of a specific procedure. Observation of students' performance during the orchiectomy showed no clear association with students' method of recollection but a significant association (p=.002) with educational input. Our results illustrate the power of a visual input and support prior findings that knowledge is constructed from multiple sources of information. PMID:27152494

  1. Precise Subcellular Input Retinotopy and Its Computational Consequences in an Identified Visual Interneuron

    PubMed Central

    Peron, Simon P.; Jones, Peter W.; Gabbiani, Fabrizio

    2009-01-01

    Summary The Lobula Giant Movement Detector (LGMD) is a higher order visual interneuron of Orthopteran insects that responds preferentially to objects approaching on a collision course. It receives excitatory input from an entire visual hemifield that anatomical evidence suggests is retinotopic. We show that this excitatory projection activates calcium-permeable nicotinic acetylcholine receptors. In vivo calcium imaging reveals that the excitatory projection preserves retinotopy down to the level of a single ommatidium. Examining the impact of retinotopy on the LGMD's computational properties, we show that sublinear synaptic summation can explain orientation preference in this cell. Exploring retinotopy's impact on directional selectivity leads us to infer that the excitatory input to the LGMD is intrinsically directionally selective. Our results show that precise retinotopy has implications for the dendritic integration of visual information in a single neuron. PMID:19778511

  2. Inputs to prefrontal cortex support visual recognition in the aging brain.

    PubMed

    Gilbert, Jessica R; Moran, Rosalyn J

    2016-01-01

    Predictive coding models of brain function propose that top-down cortical signals promote efficient neural codes by carrying predictions of upcoming sensory events. We hypothesized that older brains would employ these codes more prominently given their longer repertoire of sensory experience. We measured the connectivity underlying stimulus-evoked responses in cortical visual networks using electroencephalography and dynamic causal modeling and found that in young adults with reported normal or corrected-to-normal vision, signals propagated from early visual regions and reverberated along reciprocal connections to temporal, parietal and frontal cortices, while in contrast, the network was driven by both early visual and prefrontal inputs in older adults with reported normal or corrected-to-normal vision. Previously thought of as exceptions to the rule of bottom-up signal propagation, our results demonstrate a prominent role for prefrontal inputs in driving vision in aged brains in line with lifespan-dependent predictive neural codes. PMID:27550752

  3. Inputs to prefrontal cortex support visual recognition in the aging brain

    PubMed Central

    Gilbert, Jessica R.; Moran, Rosalyn J.

    2016-01-01

    Predictive coding models of brain function propose that top-down cortical signals promote efficient neural codes by carrying predictions of upcoming sensory events. We hypothesized that older brains would employ these codes more prominently given their longer repertoire of sensory experience. We measured the connectivity underlying stimulus-evoked responses in cortical visual networks using electroencephalography and dynamic causal modeling and found that in young adults with reported normal or corrected-to-normal vision, signals propagated from early visual regions and reverberated along reciprocal connections to temporal, parietal and frontal cortices, while in contrast, the network was driven by both early visual and prefrontal inputs in older adults with reported normal or corrected-to-normal vision. Previously thought of as exceptions to the rule of bottom-up signal propagation, our results demonstrate a prominent role for prefrontal inputs in driving vision in aged brains in line with lifespan-dependent predictive neural codes. PMID:27550752

  4. Functional topography of converging visual and auditory inputs to neurons in the rat superior colliculus.

    PubMed

    Skaliora, Irini; Doubell, Timothy P; Holmes, Nicholas P; Nodal, Fernando R; King, Andrew J

    2004-11-01

    We have used a slice preparation of the infant rat midbrain to examine converging inputs onto neurons in the deeper multisensory layers of the superior colliculus (dSC). Electrical stimulation of the superficial visual layers (sSC) and of the auditory nucleus of the brachium of the inferior colliculus (nBIC) evoked robust monosynaptic responses in dSC cells. Furthermore, the inputs from the sSC were found to be topographically organized as early as the second postnatal week and thus before opening of the eyes and ear canals. This precocious topography was found to be sculpted by GABAA-mediated inhibition of a more widespread set of connections. Tracer injections in the nBIC, both in coronal slices as well as in hemisected brains, confirmed a robust projection originating in the nBIC with distinct terminals in the proximity of the cell bodies of dSC neurons. Combined stimulation of the sSC and nBIC sites revealed that the presumptive visual and auditory inputs are summed linearly. Finally, whereas either input on its own could manifest a significant degree of paired-pulse facilitation, temporally offset stimulation of the two sites revealed no synaptic interactions, indicating again that the two inputs function independently. Taken together, these data provide the first detailed intracellular analysis of convergent sensory inputs onto dSC neurons and form the basis for further exploration of multisensory integration and developmental plasticity. PMID:15229210

  5. Topology of ON and OFF inputs in visual cortex enables an invariant columnar architecture.

    PubMed

    Lee, Kuo-Sheng; Huang, Xiaoying; Fitzpatrick, David

    2016-05-01

    Circuits in the visual cortex integrate the information derived from separate ON (light-responsive) and OFF (dark-responsive) pathways to construct orderly columnar representations of stimulus orientation and visual space. How this transformation is achieved to meet the specific topographic constraints of each representation remains unclear. Here we report several novel features of ON-OFF convergence visualized by mapping the receptive fields of layer 2/3 neurons in the tree shrew (Tupaia belangeri) visual cortex using two-photon imaging of GCaMP6 calcium signals. We show that the spatially separate ON and OFF subfields of simple cells in layer 2/3 exhibit topologically distinct relationships with the maps of visual space and orientation preference. The centres of OFF subfields for neurons in a given region of cortex are confined to a compact region of visual space and display a smooth visuotopic progression. By contrast, the centres of the ON subfields are distributed over a wider region of visual space, display substantial visuotopic scatter, and have an orientation-specific displacement consistent with orientation preference map structure. As a result, cortical columns exhibit an invariant aggregate receptive field structure: an OFF-dominated central region flanked by ON-dominated subfields. This distinct arrangement of ON and OFF inputs enables continuity in the mapping of both orientation and visual space and the generation of a columnar map of absolute spatial phase. PMID:27120162

  6. Learning Complex Grammar in the Virtual Classroom: A Comparison of Processing Instruction, Structured Input, Computerized Visual Input Enhancement, and Traditional Instruction

    ERIC Educational Resources Information Center

    Russell, Victoria

    2012-01-01

    This study investigated the effects of processing instruction (PI) and structured input (SI) on the acquisition of the subjunctive in adjectival clauses by 92 second-semester distance learners of Spanish. Computerized visual input enhancement (VIE) was combined with PI and SI in an attempt to increase the salience of the targeted grammatical form…

  7. Visualizations, Screen Shots, and Data Input Files from VisIT

    DOE Data Explorer

    VisIt is a free interactive parallel visualization and graphical analysis tool for viewing scientific data on Unix and PC platforms. Users can quickly generate visualizations from their data, animate them through time, manipulate them, and save the resulting images for presentations. VisIt contains a rich set of visualization features so that you can view your data in a variety of ways. It can be used to visualize scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured and unstructured meshes. VisIt was designed to handle very large data set sizes in the terascale range and yet can also handle small data sets in the kilobyte range. The VisIT website provides a gallery of vizualizations, another set of screen shots, and allows downloads of data files for input and source codes and executables for the VisIT software suite.

  8. Orientation selectivity and the functional clustering of synaptic inputs in primary visual cortex.

    PubMed

    Wilson, Daniel E; Whitney, David E; Scholl, Benjamin; Fitzpatrick, David

    2016-08-01

    The majority of neurons in primary visual cortex are tuned for stimulus orientation, but the factors that account for the range of orientation selectivities exhibited by cortical neurons remain unclear. To address this issue, we used in vivo two-photon calcium imaging to characterize the orientation tuning and spatial arrangement of synaptic inputs to the dendritic spines of individual pyramidal neurons in layer 2/3 of ferret visual cortex. The summed synaptic input to individual neurons reliably predicted the neuron's orientation preference, but did not account for differences in orientation selectivity among neurons. These differences reflected a robust input-output nonlinearity that could not be explained by spike threshold alone and was strongly correlated with the spatial clustering of co-tuned synaptic inputs within the dendritic field. Dendritic branches with more co-tuned synaptic clusters exhibited greater rates of local dendritic calcium events, supporting a prominent role for functional clustering of synaptic inputs in dendritic nonlinearities that shape orientation selectivity. PMID:27294510

  9. Visual cortical responses to the input from the amblyopic eye are suppressed during binocular viewing.

    PubMed

    Körtvélyes, Judit; Bankó, Eva M; Andics, A; Rudas, G; Németh, J; Hermann, Petra; Vidnyánszky, Z

    2012-01-01

    Amblyopia is a visual disorder caused by an anomalous early visual experience. It has been suggested that suppression of the visual input from the weaker eye might be a primary underlying mechanism of the amblyopic syndrome. However, it is still an unresolved question to what extent neural responses to the visual information coming from the amblyopic eye are suppressed during binocular viewing. To address this question we measured event-related potentials (ERP) to foveal face stimuli in amblyopic patients, both in monocular and binocular viewing conditions. The results revealed no difference in the amplitude and latency of early components of the ERP responses between the binocular and fellow eye stimulation. On the other hand, early ERP components were reduced and delayed in the case of monocular stimulation of the amblyopic eye as compared to the fellow eye stimulation or to binocular viewing. The magnitude of the amblyopic effect measured on the ERP amplitudes was comparable to that found on the fMRI responses in the fusiform face area using the same face stimuli and task conditions. Our findings showing that the amblyopic effects present on the early ERP components in the case of monocular stimulation are not manifested in the ERP responses during binocular viewing suggest that input from the amblyopic eye is completely suppressed already at the earliest stages of visual cortical processing when stimuli are viewed by both eyes. PMID:22453742

  10. Developmental dissociation between visual and auditory repetition priming: the role of input lexicons.

    PubMed

    Carlesimo, G A; Vicari, S; Albertoni, A; Turriziani, P; Caltagirone, C

    2000-04-01

    Contrasting theories posit the source of verbal repetition priming in the activation of preexisting memory representations in the input lexicons or, alternatively, in the formation of new episodic memory traces. The two hypotheses predict different outcomes from the comparison of developmental rates of visual and auditory verbal repetition priming. The activation theory predicts a developmental dissociation between the early maturation of auditory priming and the later maturation of visuo-verbal priming, contingent upon the discrepant acquisition rates of the auditory and visual input lexicons. The episodic theory, instead, does not make such an assumption. We administered visual and auditory implicit Stem Completion to 40 reading beginners (first-graders), 40 third-graders and 20 fifth-graders. Consistent with previous reports, auditory priming was stable across different age groups. Visual priming and a measure of lexicality in reading, instead, showed a parallel developmental increase passing from reading beginners to third-graders and to fifth-graders. In the overall group, visual priming and the measure of lexicality in reading were significantly associated. These data describe a new developmental dissociation in the memory abilities of normal children and provide further support for the hypothesis that repetition priming for words reflects facilitated access to previously established memory representations. PMID:10815705

  11. Organization of columnar inputs in the third optic ganglion of a highly visual crab.

    PubMed

    Bengochea, Mercedes; Berón de Astrada, Martín

    2014-01-01

    Motion information provides essential cues for a wide variety of animal behaviors such as mate, prey, or predator detection. In decapod crustaceans and pterygote insects, visual codification of object motion is associated with visual processing in the third optic neuropile, the lobula. In this neuropile, tangential neurons collect motion information from small field columnar neurons and relay it to the midbrain where behavioral responses would be finally shaped. In highly ordered structures, detailed knowledge of the neuroanatomy can give insight into their function. In spite of the relevance of the lobula in processing motion information, studies on the neuroarchitecture of this neuropile are scant. Here, by applying dextran-conjugated dyes in the second optic neuropile (the medulla) of the crab Neohelice, we mass stained the columnar neurons that convey visual information into the lobula. We found that the arborizations of these afferent columnar neurons lie at four main lobula depths. A detailed examination of serial optical sections of the lobula revealed that these input strata are composed of different number of substrata and that the strata are thicker in the centre of the neuropile. Finally, by staining the different lobula layers composed of tangential processes we combined the present characterization of lobula input strata with the previous characterization of the neuroarchitecture of the crab's lobula based on reduced-silver preparations. We found that the third lobula input stratum overlaps with the dendrites of lobula giant tangential neurons. This suggests that columnar neurons projecting from the medulla can directly provide visual input to the crab's lobula giant neurons. PMID:24929118

  12. Serendipity in Technetium-99m dimethyl iminodiacetic acid cholescintigraphy. [Visualization of nonbiliary incidental abnormalities

    SciTech Connect

    Weissmann, H.S.; Sugarman, L.A.; Frank, M.S.; Freeman, L.M.

    1980-05-01

    Technetium-99m dimethyl iminodiacetic acid cholescintigraphy has contributed significantly to the diagnosis of acute and chronic biliary tract disorders. Yet attention should also be focused on the other structres visualized during the blood pool, hepatocyte, renal excretory, and intestinal phases of the study. Nonbiliary pathology was detected in 42 of 294 patients (14.3%) studied for suspected acute cholecystitis. The serendipitous detection of previously unsuspected abnormalities assisted in directing further work-up away from suspected biliary disease and towards the real source of the patient's acute problem in 28 cases (9.5%).

  13. Thalamus provides layer 4 of primary visual cortex with orientation- and direction-tuned inputs

    PubMed Central

    Sun, Wenzhi; Tan, Zhongchao; Mensh, Brett D.; Ji, Na

    2015-01-01

    Understanding the functions of a brain region requires knowing the neural representations of its myriad inputs, local neurons, and outputs. Primary visual cortex (V1) has long been thought to compute visual orientation from untuned thalamic inputs, but very few thalamic inputs have been measured in any mammal. We determined the response properties of ~28,000 thalamic boutons and ~4,000 cortical neurons in layers 1–5 of awake mouse V1. With adaptive optics allowing accurate measurement of bouton activity deep in cortex, we found that around half of the boutons in the main thalamorecipient L4 carry orientation-tuned information, and their orientation/direction biases are also dominant in the L4 neuron population, suggesting that these neurons may inherit their selectivity from tuned thalamic inputs. Cortical neurons in all layers exhibited sharper tuning than thalamic boutons and a greater diversity of preferred orientations. Our results provide data-rich constraints for refining mechanistic models of cortical computation. PMID:26691829

  14. Thalamus provides layer 4 of primary visual cortex with orientation- and direction-tuned inputs.

    PubMed

    Sun, Wenzhi; Tan, Zhongchao; Mensh, Brett D; Ji, Na

    2016-02-01

    Understanding the functions of a brain region requires knowing the neural representations of its myriad inputs, local neurons and outputs. Primary visual cortex (V1) has long been thought to compute visual orientation from untuned thalamic inputs, but very few thalamic inputs have been measured in any mammal. We determined the response properties of ∼ 28,000 thalamic boutons and ∼ 4,000 cortical neurons in layers 1-5 of awake mouse V1. Using adaptive optics that allows accurate measurement of bouton activity deep in cortex, we found that around half of the boutons in the main thalamorecipient L4 carried orientation-tuned information and that their orientation and direction biases were also dominant in the L4 neuron population, suggesting that these neurons may inherit their selectivity from tuned thalamic inputs. Cortical neurons in all layers exhibited sharper tuning than thalamic boutons and a greater diversity of preferred orientations. Our results provide data-rich constraints for refining mechanistic models of cortical computation. PMID:26691829

  15. On the Visual Input Driving Human Smooth-Pursuit Eye Movements

    NASA Technical Reports Server (NTRS)

    Stone, Leland S.; Beutter, Brent R.; Lorenceau, Jean

    1996-01-01

    Current computational models of smooth-pursuit eye movements assume that the primary visual input is local retinal-image motion (often referred to as retinal slip). However, we show that humans can pursue object motion with considerable accuracy, even in the presence of conflicting local image motion. This finding indicates that the visual cortical area(s) controlling pursuit must be able to perform a spatio-temporal integration of local image motion into a signal related to object motion. We also provide evidence that the object-motion signal that drives pursuit is related to the signal that supports perception. We conclude that current models of pursuit should be modified to include a visual input that encodes perceived object motion and not merely retinal image motion. Finally, our findings suggest that the measurement of eye movements can be used to monitor visual perception, with particular value in applied settings as this non-intrusive approach would not require interrupting ongoing work or training.

  16. From faces to hands: Changing visual input in the first two years.

    PubMed

    Fausey, Caitlin M; Jayaraman, Swapnaa; Smith, Linda B

    2016-07-01

    Human development takes place in a social context. Two pervasive sources of social information are faces and hands. Here, we provide the first report of the visual frequency of faces and hands in the everyday scenes available to infants. These scenes were collected by having infants wear head cameras during unconstrained everyday activities. Our corpus of 143hours of infant-perspective scenes, collected from 34 infants aged 1month to 2years, was sampled for analysis at 1/5Hz. The major finding from this corpus is that the faces and hands of social partners are not equally available throughout the first two years of life. Instead, there is an earlier period of dense face input and a later period of dense hand input. At all ages, hands in these scenes were primarily in contact with objects and the spatio-temporal co-occurrence of hands and faces was greater than expected by chance. The orderliness of the shift from faces to hands suggests a principled transition in the contents of visual experiences and is discussed in terms of the role of developmental gates on the timing and statistics of visual experiences. PMID:27043744

  17. Magnetoencephalographic evidence for non-geniculostriate visual input to human cortical area V5.

    PubMed

    Holliday, I E; Anderson, S J; Harding, G F

    1997-08-01

    The aim of this study was to establish whether there is non-geniculostriate input to the extrastriate motion-sensitive area V5 in humans. Responses were measured with a SQUID neuro-magnetometer to motion stimuli presented within the blind hemifield of GY, a well-documented subject with a complete absence of the left primary visual cortical area V1. The motion stimulus was a 0.5c/deg, rapidly drifting (16Hz) achromatic sinusoidal grating. With this stimulus, the magnetic responses recorded over the temporo-parieto-occipital region in normals are well modelled by localized current sources in areas V1 and V5 (Anderson, S. J. et al., Proceedings of the Royal Society, London, Series B, 1996, 263, 423-431). As a control, evoked responses were measured to a 1.0 c/deg, stationary, photometrically isoluminant red/green sinusoidal grating. With the chromatic stimulus, the principal component of the magnetic responses recorded over the occipital pole in normals is well modelled by a current source in area V1 (Fylan, F. et al., Investigative Ophthalmology and Visual Science, 1995, 36, s1053). Both stimuli subtended 4 deg vertically by 6 deg horizontally, positioned such that the stimulus extended beyond the area of macular sparing into the lower field quadrant of the blind (or sighted) hemifield. Chromatic stimuli failed to evoked responses from GY's blind (contralateral) hemifield, consistent with there being no V1 activity in his left cortical hemisphere. However, motion stimuli did evoke responses from GY's blind hemifield, originating from a location consistent with activity in area V5. We further observed that both colour and motion stimuli evoked responses from GY's sighted (ipsilateral) hemifield. We conclude that there is non-geniculostriate input to extrastriate motion-sensitive areas in the human visual system, and that this pathway subserves the residual visual sensitivity to motion in the blind hemifield that has been demonstrated psychophysically in observer GY

  18. The Visual Input to the Retina during Natural Head-Free Fixation

    PubMed Central

    Victor, Jonathan D.; Rucci, Michele

    2014-01-01

    Head and eye movements incessantly modulate the luminance signals impinging onto the retina during natural intersaccadic fixation. Yet, little is known about how these fixational movements influence the statistics of retinal stimulation. Here, we provide the first detailed characterization of the visual input to the human retina during normal head-free fixation. We used high-resolution recordings of head and eye movements in a natural viewing task to examine how they jointly transform spatial information into temporal modulations. In agreement with previous studies, we report that both the head and the eyes move considerably during fixation. However, we show that fixational head and eye movements mostly compensate for each other, yielding a spatiotemporal redistribution of the input power to the retina similar to that previously observed under head immobilization. The resulting retinal image motion counterbalances the spectral distribution of natural scenes, giving temporal modulations that are equalized in power over a broad range of spatial frequencies. These findings support the proposal that “ocular drift,” the smooth fixational motion of the eye, is under motor control, and indicate that the spatiotemporal reformatting caused by fixational behavior is an important computational element in the encoding of visual information. PMID:25232108

  19. Dyspraxia in a patient with corticobasal degeneration: the role of visual and tactile inputs to action

    PubMed Central

    Graham, N.; Zeman, A.; Young, A.; Patterson, K.; Hodges, J.

    1999-01-01

    OBJECTIVES—To investigate the roles of visual and tactile information in a dyspraxic patient with corticobasal degeneration (CBD) who showed dramatic facilitation in miming the use of a tool or object when he was given a tool to manipulate; and to study the nature of the praxic and neuropsychological deficits in CBD.
METHODS—The subject had clinically diagnosed CBD, and exhibited alien limb behaviour and striking ideomotor dyspraxia. General neuropsychological evaluation focused on constructional and visuospatial abilities, calculation, verbal fluency, episodic and semantic memory, plus spelling and writing because impairments in this domain were presenting complaints. Four experiments assessed the roles of visual and tactile information in the facilitation of motor performance by tools. Experiment 1 evaluated the patient's performance of six limb transitive actions under six conditions: (1) after he described the relevant tool from memory, (2) after he was shown a line drawing of the tool, (3) after he was shown a real exemplar of the tool, (4) after he watched the experimenter perform the action, (5) while he was holding the tool, and (6) immediately after he had performed the action with the tool but with the tool removed from his grasp. Experiment 2 evaluated the use of the same six tools when the patient had tactile but no visual information (while he was blindfolded). Experiments 3 and 4 assessed performance of actions appropriate to the same six tools when the patient had either neutral or inappropriate tactile feedback—that is, while he was holding a non-tool object or a different tool.
RESULTS—Miming of tool use was not facilitated by visual input; moreover, lack of visual information in the blindfolded condition did not reduce performance. The principal positive finding was a dramatic facilitation of the patient's ability to demonstrate object use when he was holding either the appropriate tool or a neutral object. Tools inappropriate to the

  20. Oscillatory Recruitment of Bilateral Visual Cortex during Spatial Attention to Competing Rhythmic Inputs

    PubMed Central

    Gray, Michael J.; Frey, Hans-Peter; Wilson, Tommy J.

    2015-01-01

    Selective attention uses temporal regularity of relevant inputs to bias the phase of ongoing population-level neuronal oscillations. This phase entrainment streamlines processing, allowing attended information to arrive at moments of high neural excitability. How entrainment resolves competition between spatially segregated inputs during visuospatial tasks is not yet established. Using high-density electroencephalography in humans, a bilateral entrainment response to the rhythm (1.3 or 1.5 Hz) of an attended stimulation stream was observed, concurrent with a considerably weaker contralateral entrainment to a competing rhythm. That ipsilateral visual areas strongly entrained to the attended stimulus is notable because competitive inputs to these regions were being driven at an entirely different rhythm. Strong modulations of phase locking and weak modulations of single-trial power suggest that entrainment was primarily driven by phase-alignment of ongoing oscillatory activity. In addition, interhemispheric differences in entrained phase were found to be modulated by attended hemifield, implying that the bilateral nature of the response reflected a functional flow of information between hemispheres. This modulation was strongest at the third of at least four harmonics that were strongly entrained. Ipsilateral increases in alpha-band (8–12 Hz) power were also observed during bilateral entrainment, reflecting suppression of the ignored stimulation stream. Furthermore, both entrainment and alpha lateralization significantly affected task performance. We conclude that oscillatory entrainment is a functionally relevant mechanism that synchronizes endogenous activity across the cortical hierarchy to resolve spatial competition. We further speculate that concurrent suppression of ignored input might facilitate the widespread propagation of attended information during spatial attention. PMID:25855167

  1. PDF-modulated visual inputs and cryptochrome define diurnal behavior in Drosophila.

    PubMed

    Cusumano, Paola; Klarsfeld, André; Chélot, Elisabeth; Picot, Marie; Richier, Benjamin; Rouyer, François

    2009-11-01

    Morning and evening circadian oscillators control the bimodal activity of Drosophila in light-dark cycles. The lateral neurons evening oscillator (LN-EO) is important for promoting diurnal activity at dusk. We found that the LN-EO autonomously synchronized to light-dark cycles through either the cryptochrome (CRY) that it expressed or the visual system. In conditions in which CRY was not activated, flies depleted for pigment-dispersing factor (PDF) or its receptor lost the evening activity and displayed reversed PER oscillations in the LN-EO. Rescue experiments indicated that normal PER cycling and the presence of evening activity relied on PDF secretion from the large ventral lateral neurons and PDF receptor function in the LN-EO. The LN-EO thus integrates light inputs and PDF signaling to control Drosophila diurnal behavior, revealing a new clock-independent function for PDF. PMID:19820704

  2. Visual Predictive Check in Models with Time-Varying Input Function.

    PubMed

    Largajolli, Anna; Bertoldo, Alessandra; Campioni, Marco; Cobelli, Claudio

    2015-11-01

    The nonlinear mixed effects models are commonly used modeling techniques in the pharmaceutical research as they enable the characterization of the individual profiles together with the population to which the individuals belong. To ensure a correct use of them is fundamental to provide powerful diagnostic tools that are able to evaluate the predictive performance of the models. The visual predictive check (VPC) is a commonly used tool that helps the user to check by visual inspection if the model is able to reproduce the variability and the main trend of the observed data. However, the simulation from the model is not always trivial, for example, when using models with time-varying input function (IF). In this class of models, there is a potential mismatch between each set of simulated parameters and the associated individual IF which can cause an incorrect profile simulation. We introduce a refinement of the VPC by taking in consideration a correlation term (the Mahalanobis or normalized Euclidean distance) that helps the association of the correct IF with the individual set of simulated parameters. We investigate and compare its performance with the standard VPC in models of the glucose and insulin system applied on real and simulated data and in a simulated pharmacokinetic/pharmacodynamic (PK/PD) example. The newly proposed VPC performance appears to be better with respect to the standard VPC especially for the models with big variability in the IF where the probability of simulating incorrect profiles is higher. PMID:26265094

  3. Local structure of subcellular input retinotopy in an identified visual interneuron

    NASA Astrophysics Data System (ADS)

    Zhu, Ying; Gabbiani, Fabrizio; Fabrizio Gabbiani's lab Team

    2015-03-01

    How does the spatial layout of the projections that a neuron receives impact its synaptic integration and computation? What is the mapping topography of subcellular wiring at the single neuron level? The LGMD (lobula giant movement detector) neuron in the locust is an identified neuron that responds preferentially to objects approaching on a collision course. It receives excitatory inputs from the entire visual hemifield through calcium-permeable nicotinic acetylcholine receptors. Previous work showed that the projection from the locust compound eye to the LGMD preserved retinotopy down to the level of a single ommatidium (facet) by employing in vivo widefield calcium imaging. Because widefield imaging relies on global excitation of the preparation and has a relatively low resolution, previous work could not investigate this retinotopic mapping at the level of individual thin dendritic branches. Our current work employs a custom-built two-photon microscope with sub-micron resolution in conjunction with a single-facet stimulation setup that provides visual stimuli to the single ommatidium of locust adequate to explore the local structure of this retinotopy at a finer level. We would thank NIMH for funding this research.

  4. Influence of visual inputs on quasi-static standing postural steadiness in individuals with spinal cord injury.

    PubMed

    Lemay, Jean-François; Gagnon, Dany; Duclos, Cyril; Grangeon, Murielle; Gauthier, Cindy; Nadeau, Sylvie

    2013-06-01

    Postural steadiness while standing is impaired in individuals with spinal cord injury (SCI) and could be potentially associated with increased reliance on visual inputs. The purpose of this study was to compare individuals with SCI and able-bodied participants on their use of visual inputs to maintain standing postural steadiness. Another aim was to quantify the association between visual contribution to achieve postural steadiness and a clinical balance scale. Individuals with SCI (n = 15) and able-bodied controls (n = 14) performed quasi-static stance, with eyes open or closed, on force plates for two 45 s trials. Measurements of the centre of pressure (COP) included the mean value of the root mean square (RMS), mean COP velocity (MV) and COP sway area (SA). Individuals with SCI were also evaluated with the Mini-Balance Evaluation Systems Test (Mini BESTest), a clinical outcome measure of postural steadiness. Individuals with SCI were significantly less stable than able-bodied controls in both conditions. The Romberg ratios (eyes open/eyes closed) for COP MV and SA were significantly higher for individuals with SCI, indicating a higher contribution of visual inputs for postural steadiness in that population. Romberg ratios for RMS and SA were significantly associated with the Mini-BESTest. This study highlights the contribution of visual inputs in individuals with SCI when maintaining quasi-static standing posture. PMID:23332191

  5. Kainate Receptors Mediate Synaptic Input to Transient and Sustained OFF Visual Pathways in Primate Retina

    PubMed Central

    Percival, Kumiko A.; Venkataramani, Sowmya; Gayet-Primo, Jacqueline; Grünert, Ulrike; Taylor, W. Rowland

    2014-01-01

    Visual signals are segregated into parallel pathways at the first synapse in the retina between cones and bipolar cells. Within the OFF pathways of mammals, the selective expression of AMPA or kainate-type glutamate receptors in the dendrites of different OFF-bipolar cell types is thought to contribute to formation of distinct temporal channels. AMPA receptors, with rapid recovery from desensitization, are proposed to transmit high temporal frequency signals, whereas kainate receptors (KARs) are presumed to encode lower temporal frequencies. Here we studied the glutamate receptors expressed by OFF-bipolar cells in slice preparations of macaque monkey retina, where the low (midget/parvocellular) and high-frequency (parasol/magnocellular) temporal channels are well characterized. We found that all OFF-bipolar types receive input primarily through KARs and that KAR antagonists block light-evoked input to both OFF-midget and OFF-parasol ganglion cells. KAR subunits were differentially expressed in OFF-bipolar types; the diffuse bipolar (DB) cells, DB2 and DB3b, expressed GluK1 and showed transient responses to glutamate and the KAR agonist, ATPA. In contrast, flat midget bipolar, DB1, and DB3a cells lacked GluK1 and showed relatively sustained responses. Finally, we found that the KAR accessory protein, Neto1, is expressed at the base of cone pedicles but is not colocalized with the GluK1 subunit. In summary, the results indicate that transient signaling in the OFF pathway of macaques is not dependent on AMPA receptors and that heterogeneity of KARs and accessory proteins may contribute to the formation of parallel temporal channels. PMID:24872565

  6. Paradoxical visuomotor adaptation to reversed visual input is predicted by BDNF Val66Met polymorphism

    PubMed Central

    Barton, Brian; Treister, Andrew; Humphrey, Melanie; Abedi, Garen; Cramer, Steven C.; Brewer, Alyssa A.

    2014-01-01

    Brain-derived neurotrophic factor (BDNF) is the most abundant neurotrophin in the brain, influencing neural development, plasticity, and repair (Chen et al., 2004; Thoenen, 1995). The BDNF gene contains a single-nucleotide polymorphism (SNP) called Val66Met. The Met allele interferes with intracellular BDNF-trafficking, decreases activity-dependent BDNF secretion, and consequently is often associated with a shift from plasticity to stability in neural circuits (Egan et al., 2003). We investigated the behavioral consequences of the presence of the Met allele by comparing how 40 heterozygous subjects with the Val/Met genotype and 35 homozygous subjects with the Val/Val genotype performed on visuomotor tasks (reaching and navigation) under two conditions: normal vision and completely left-right reversed vision. As expected, subjects did not differ in their short-term ability to learn the tasks with normal vision (p = 0.58). Intuitively, it would be expected that homozygous Val/Val subjects with a propensity for greater BDNF-induced activity-dependent plasticity would learn new tasks more quickly than heterozygous Val/Met subjects with decreased BDNF secretion (Gilbert, Li, & Piech, 2009). However, we found the opposite here. When short-term mechanisms of visuomotor adaptation were engaged to compensate for the misalignment of visual and somatomotor information created by the left-right reversal of vision, heterozygous Val/Met subjects learned significantly more quickly than their homozygous Val/Val counterparts (p = 0.027). Our results demonstrate the paradoxical finding that the presence of the Met allele, which is thought to promote cortical stability, here improves immediate visuomotor adaptation to left–right-reversed visual input. PMID:25104829

  7. Olfactory input increases visual sensitivity in zebrafish: a possible function for the terminal nerve and dopaminergic interplexiform cells.

    PubMed

    Maaswinkel, Hans; Li, Lei

    2003-07-01

    Centrifugal innervation of the neural retina has been documented in many species. In zebrafish Danio rerio, the only so-far described centrifugal pathway originates from terminal nerve (TN) cell bodies that are located in the olfactory bulb. Most of the TN axons terminate in the forebrain and midbrain, but some project via the optic nerve to the neural retina, where they synapse onto dopaminergic interplexiform cells (DA-IPCs). While the anatomical pathway between the olfactory and visual organs has been described, it is unknown if and how olfactory signals influence visual system functions. We demonstrate here that olfactory input is involved in the modulation of visual sensitivity in zebrafish. As determined by a behavioral assay and by electroretinographic (ERG) recording, zebrafish visual sensitivity was increased upon presentation of amino acids as olfactory stimuli. This effect, however, was observed only in the early morning hours when zebrafish are least sensitive to light. The effect of olfactory input on vision was eliminated after lesion of the olfactory bulbs or after the destruction of DA-IPCs. Intraocular injections of a dopamine D(2) but not a D(1) receptor antagonist blocked the effect of olfactory input on visual sensitivity. Although we cannot exclude the involvement of other anatomical pathways, our data suggest that the TN and DA-IPCs are the prime candidates for olfactory modulation of visual sensitivity. PMID:12771169

  8. Visual input controls the functional activity of goldfish Mauthner neuron through the reciprocal synaptic mechanism.

    PubMed

    Moshkov, Dmitry A; Shtanchaev, Rashid S; Mikheeva, Irina B; Bezgina, Elena N; Kokanova, Nadezhda A; Mikhailova, Gulnara Z; Tiras, Nadezhda R; Pavlik, Lyubov' L

    2013-03-01

    Goldfish are known to exhibit motor asymmetry due to functional asymmetry of their Mauthner neurons that induce the turns to the right or left during free swimming. It has been previously found that if the less active neuron is subjected to prolonged aimed visual stimulation via its ventral dendrite, the motor asymmetry of goldfish is inverted, testifying that this neuron becomes functionally dominant, while the size of the ventral dendrite under these conditions is reduced 2-3 times compared to its counterpart in mirror neuron. Earlier it has been also revealed that training optokinetic stimulation induces adaptation, a substantial resistance of both fish motor asymmetry and morphofunctional state of Mauthner neurons against prolonged optokinetic stimulation. The aim of this work was to study the cellular mechanisms of the effect of an unusual visual afferent input on goldfish motor asymmetry and Mauthner neuron function in norm and under adaptation. It was shown that serotonin applied onto Mauthner neurons greatly reduces their activity whereas its antagonist ondansetron increases it. Against the background of visual stimulation, serotonin strengthens functional asymmetry between neurons whereas ondansetron smoothes it. Taken together these data suggest the involvement of serotonergic excitatory synaptic transmission in the regulation of Mauthner neurons by vision. Ultrastructural study of the ventral dendrites after prolonged optokinetic stimulation has revealed depletions of numeral axo-axonal synapses with specific morphology, identified by means of immunogold label as serotonergic ones. These latter in turn are situated mainly on shaft boutons, which according to specific ultrastructural features are assigned to axo-dendritic inhibitory synapses. Thus, the excitatory serotonergic synapses seem to affect Mauthner neuron indirectly through inhibitory synapses. Further, it was morphometrically established that adaptation is accompanied by the significant

  9. Development and Implementation of Software for Visualizing and Editing Multidimensional Flight Simulation Input Data

    NASA Technical Reports Server (NTRS)

    Whelan, Todd Michael

    1996-01-01

    In a real-time or batch mode simulation that is designed to model aircraft dynamics over a wide range of flight conditions, a table look- up scheme is implemented to determine the forces and moments on the vehicle based upon the values of parameters such as angle of attack, altitude, Mach number, and control surface deflections. Simulation Aerodynamic Variable Interface (SAVI) is a graphical user interface to the flight simulation input data, designed to operate on workstations that support X Windows. The purpose of the application is to provide two and three dimensional visualization of the data, to allow an intuitive sense of the data set. SAVI also allows the user to manipulate the data, either to conduct an interactive study of the influence of changes on the vehicle dynamics, or to make revisions to data set based on new information such as flight test. This paper discusses the reasons for developing the application, provides an overview of its capabilities, and outlines the software architecture and operating environment.

  10. Preserved local but disrupted contextual figure-ground influences in an individual with abnormal function of intermediate visual areas

    PubMed Central

    Brooks, Joseph L.; Gilaie-Dotan, Sharon; Rees, Geraint; Bentin, Shlomo; Driver, Jon

    2012-01-01

    Visual perception depends not only on local stimulus features but also on their relationship to the surrounding stimulus context, as evident in both local and contextual influences on figure-ground segmentation. Intermediate visual areas may play a role in such contextual influences, as we tested here by examining LG, a rare case of developmental visual agnosia. LG has no evident abnormality of brain structure and functional neuroimaging showed relatively normal V1 function, but his intermediate visual areas (V2/V3) function abnormally. We found that contextual influences on figure-ground organization were selectively disrupted in LG, while local sources of figure-ground influences were preserved. Effects of object knowledge and familiarity on figure-ground organization were also significantly diminished. Our results suggest that the mechanisms mediating contextual and familiarity influences on figure-ground organization are dissociable from those mediating local influences on figure-ground assignment. The disruption of contextual processing in intermediate visual areas may play a role in the substantial object recognition difficulties experienced by LG. PMID:22947116

  11. Subjective Visual Vertical and Horizontal Abnormalities in a Patient with Lateral Medullary Syndrome-A Case Report

    PubMed Central

    Tyagi, Amit Kumar; Ashish, Gaurav; Lepcha, Anjali; Balraj, Achamma

    2015-01-01

    Introduction: Evaluation of persistent vertigo in post infarct patients is very important as the management depends on whether the cause is purely of central origin or due to associated vestibular affliction. Case Report: A patient with left sided dorsolateral medullary syndrome and persistent vestibular symptoms was evaluated. Vestibular test battery showed abnormal smooth pursuit, bilateral hyperactive caloric responses, and abnormal dynamic subjective visual vertical and dynamic subjective visual horizontal tests. Conclusion: Dorsolateral medullary infarctions (Wallenberg’s syndrome) typically cause a central vestibular tonus imbalance in the roll plane with ipsilateral deviations of perceived vertical orientation. The SVV and SVH tests may have a role in localizing the pathology in a patient with lateral medullary syndrome. PMID:25745615

  12. Visual Input Enhancement via Essay Coding Results in Deaf Learners' Long-Term Retention of Improved English Grammatical Knowledge

    ERIC Educational Resources Information Center

    Berent, Gerald P.; Kelly, Ronald R.; Schmitz, Kathryn L.; Kenney, Patricia

    2009-01-01

    This study explored the efficacy of visual input enhancement, specifically "essay enhancement", for facilitating deaf college students' improvement in English grammatical knowledge. Results documented students' significant improvement immediately after a 10-week instructional intervention, a replication of recent research. Additionally, the…

  13. Visual cortical input alters spatial tuning in monkey lateral geniculate nucleus cells.

    PubMed Central

    McClurkin, J W; Marrocco, R T

    1984-01-01

    The response of monkey lateral geniculate nucleus (l.g.n.) cells to flashing spots, annuli, and drifting sine-wave gratings were recorded with tungsten micro-electrodes. These stimuli were presented (a) monocularly, through an aperture in the centre of a radial grating, or (b) dichoptically, in which the spots or drifting gratings were presented to the dominant eye's receptive field, while the centre of the radial grating was positioned on the corresponding retinal location of the other eye. Movement of the radial grating produced changes in the l.g.n. cell responses evoked by the spots and sine-wave gratings. These changes were reversed by cryogenic blockade of the striate cortex. Therefore, radial grating movement altered the responses of l.g.n. cells by activating the corticogeniculate (c.g.) pathway. In about half of all cells, radial grating-induced alterations of centre, or surround, or both responses to spots and annuli were produced. By adopting a simple spatial filtering model of the centre and surround mechanisms, it was possible to predict how these alterations in centre/surround balance would affect the cell's responses to sine-wave gratings. Alterations were observed in the peak and band width of the spatial and/or temporal tuning curves. The radial gratings did not alter the spatial summation properties of cells. Minor alterations in the spectral neutral points of chromatically opponent neurones were occasionally found. These results are interpreted as support for the view that spatial and temporal tuning are dynamic properties of some l.g.n. neurones by virtue of descending input from the visual cortex. PMID:6716281

  14. Detecting Visual Function Abnormality with a Contrast-Dependent Visual Test in Patients with Type 2 Diabetes.

    PubMed

    Tsai, Li-Ting; Liao, Kuo-Meng; Jang, Yuh; Hu, Fu-Chang; Wu, Wei-Chi

    2016-01-01

    In addition to diabetic retinopathy, diabetes also causes early retinal neurodegeneration and other eye problems, which cause various types of visual deficits. This study used a computer-based visual test (Macular Multi-Function Assessment (MMFA)) to assess contrast-dependent macular visual function in patients with type 2 diabetes to collect more visual information than possible with only the visual acuity test. Because the MMFA is a newly developed test, this study first compared the agreement and discriminative ability of the MMFA and the Early Treatment Diabetic Retinopathy Study (ETDRS) contrast acuity charts. Then symbol discrimination performances of diabetic patients and controls were evaluated at 4 contrast levels using the MMFA. Seventy-seven patients and 45 controls participated. The agreement between MMFA and ETDRS scores was examined by fitting three-level linear mixed-effect models to estimate the intraclass correlation coefficients (ICCs). The estimated areas under the receiver operating characteristic (ROC) curve were used to compare the discriminative ability of diseased versus non-diseased participants between the two tests. The MMFA scores of patients and controls were compared with multiple linear regression analysis after adjusting the effects of age, sex, hypertension and cataract. Results showed that the scores of the MMFA and ETDRS tests displayed high levels of agreement and acceptable and similar discriminative ability. The MMFA performance was correlated with the severity of diabetic retinopathy. Most of the MMFA scores differed significantly between the diabetic patients and controls. In the low contrast condition, the MMFA scores were significantly lower for 006Eon-DR patients than for controls. The potential utility of the MMFA as an easy screening tool for contrast-dependent visual function and for detecting early functional visual change in patients with type 2 diabetes is discussed. PMID:27611680

  15. Flexibility of vestibulo-ocular reflex adaptation to modified visual input in human.

    PubMed

    Watanabe, Shoji; Hattori, Kosuke; Koizuka, Izumi

    2003-02-01

    The vestibulo-ocular reflex (VOR) serves to keep images relatively stable on the retina. To maintain appropriate performance and minimize image slip throughout life, VOR is subjected to long-term adaptive regulation by visual input. It has been reported that adaptive changes in VOR gain (eye velocity/head velocity) are evoked either by fitting subjects with magnifying, miniaturizing, or reversing spectacles during normal behavior, or by moving a large visual field in or out of phase relative to the subject's head movement. The changes in VOR gain are frequency selective. Here, we examine the extent of VOR gain flexibility by causing VORs of similar direction to undergo different behavioral gain changes. Nine healthy adults participated in the study, ranging in age from 24 to 38 years (mean: 26 years) and with no history of neurotological symptoms. All subjects were clinically normal according to a screening battery that included combined neurologic and otologic physical examinations. Horizontal and vertical eye positions were recorded by bitemporal DC-coupled electro-oculography (EOG). The subject sat in a rotating chair. The axis of rotation of the body was always earth-vertical, with the interaural axis crossing the axis of rotation of the chair. The head was pointed 20 degrees downwards in all experiments and stabilized in this position using a chin rest. The chair was surrounded by a half-cylindrical optokinetic screen (78 cm in diameter) placed in front of the subject, onto which random dot patterns were projected. Goggles were used to ensure that the subject was in complete darkness during both pre- and postadaptation periods. The chair was rotated sinusoidally at maximum amplitude of 30 degrees or 60 degrees : for 30 degrees the stimulation was at 0.1, 0.2, 0.3, and 0.4 Hz; for 60 degrees it was at 0.1, 0.2, and 0.3 Hz. VOR adaptation was obtained by inducing a retinal slip velocity by short-term alteration of the visual input of the large field; this change

  16. [Flexibility in the adaptation of the vestibulo-ocular reflex to modified visual inputs in humans].

    PubMed

    Hattori, K; Watanabe, S; Nakamura, T; Kato, I

    2000-10-01

    The vestibulo-ocular reflex (VOR) serves to stabilize images on the retina. To maintain appropriate performance and minimize image slippage throughout life, the VOR is subject to long-term adaptive regulation in response to visual input. Adaptive changes in VOR gain (eye velocity/head velocity) can be evoked either by fitting subjects with magnifying, miniaturizing, or reversing spectacles during normal behavior or by moving a large visual field in or out of phase relative to the subject's head movement. These changes exhibit frequency-selectivity. Here, we examine the flexibility of VOR gains by causing VOR in similar directions to undergo different behavioral gain changes. Nine healthy adults, ranging in age from 24 to 38 (mean 28.5) with no history of neurotological symptoms participated in the study. All subjects demonstrated clinically normal functioning on a screening battery of tests that included combined neurologic and otologic physical examinations. Horizontal and vertical eye positions were recorded by bitemporal DC coupled electrooculography (EOG). The subject sat in a rotating chair. The axis of rotation of the body was always earth-vertical, the interaural axis crossing the axis of rotation of the chair. The head was positioned at 20 degrees down in all experiments and was stabilized in this position using a chin rest. The chair was 78 cm in diameter and was shielded by a half-cylindrical optokinetic screen positioned in front of the subjects. Random dot patterns were projected onto this screen. During per- and post-adaptation periods, goggles were fitted to ensure that the subject was in complete darkness and the chair was rotated sinusoidally. The amplitude of the rotating chair was 30 degrees and 60 degrees. Frequencies of rotation were 0.1 Hz, 0.2 Hz, 0.3 Hz and 0.4 Hz for amplitudes of 30 degrees and 0.1 Hz, 0.2 Hz, and 0.3 Hz for amplitudes of 60 degrees. To induce VOR adaptation, the retinal slippage velocity caused by the visual input of a

  17. Do Visual and Vestibular Inputs Compensate for Somatosensory Loss in the Perception of Spatial Orientation? Insights from a Deafferented Patient.

    PubMed

    Bringoux, Lionel; Scotto Di Cesare, Cécile; Borel, Liliane; Macaluso, Thomas; Sarlegna, Fabrice R

    2016-01-01

    The present study aimed at investigating the consequences of a massive loss of somatosensory inputs on the perception of spatial orientation. The occurrence of possible compensatory processes for external (i.e., object) orientation perception and self-orientation perception was examined by manipulating visual and/or vestibular cues. To that aim, we compared perceptual responses of a deafferented patient (GL) with respect to age-matched Controls in two tasks involving gravity-related judgments. In the first task, subjects had to align a visual rod with the gravitational vertical (i.e., Subjective Visual Vertical: SVV) when facing a tilted visual frame in a classic Rod-and-Frame Test. In the second task, subjects had to report whether they felt tilted when facing different visuo-postural conditions which consisted in very slow pitch tilts of the body and/or visual surroundings away from vertical. Results showed that, much more than Controls, the deafferented patient was fully dependent on spatial cues issued from the visual frame when judging the SVV. On the other hand, the deafferented patient did not rely at all on visual cues for self-tilt detection. Moreover, the patient never reported any sensation of tilt up to 18° contrary to Controls, hence showing that she did not rely on vestibular (i.e., otoliths) signals for the detection of very slow body tilts either. Overall, this study demonstrates that a massive somatosensory deficit substantially impairs the perception of spatial orientation, and that the use of the remaining sensory inputs available to a deafferented patient differs regarding whether the judgment concerns external vs. self-orientation. PMID:27199704

  18. Do Visual and Vestibular Inputs Compensate for Somatosensory Loss in the Perception of Spatial Orientation? Insights from a Deafferented Patient

    PubMed Central

    Bringoux, Lionel; Scotto Di Cesare, Cécile; Borel, Liliane; Macaluso, Thomas; Sarlegna, Fabrice R.

    2016-01-01

    The present study aimed at investigating the consequences of a massive loss of somatosensory inputs on the perception of spatial orientation. The occurrence of possible compensatory processes for external (i.e., object) orientation perception and self-orientation perception was examined by manipulating visual and/or vestibular cues. To that aim, we compared perceptual responses of a deafferented patient (GL) with respect to age-matched Controls in two tasks involving gravity-related judgments. In the first task, subjects had to align a visual rod with the gravitational vertical (i.e., Subjective Visual Vertical: SVV) when facing a tilted visual frame in a classic Rod-and-Frame Test. In the second task, subjects had to report whether they felt tilted when facing different visuo-postural conditions which consisted in very slow pitch tilts of the body and/or visual surroundings away from vertical. Results showed that, much more than Controls, the deafferented patient was fully dependent on spatial cues issued from the visual frame when judging the SVV. On the other hand, the deafferented patient did not rely at all on visual cues for self-tilt detection. Moreover, the patient never reported any sensation of tilt up to 18° contrary to Controls, hence showing that she did not rely on vestibular (i.e., otoliths) signals for the detection of very slow body tilts either. Overall, this study demonstrates that a massive somatosensory deficit substantially impairs the perception of spatial orientation, and that the use of the remaining sensory inputs available to a deafferented patient differs regarding whether the judgment concerns external vs. self-orientation. PMID:27199704

  19. Resting-State Retinotopic Organization in the Absence of Retinal Input and Visual Experience

    PubMed Central

    Binda, Paola; Benson, Noah C.; Bridge, Holly; Watkins, Kate E.

    2015-01-01

    Early visual areas have neuronal receptive fields that form a sampling mosaic of visual space, resulting in a series of retinotopic maps in which the same region of space is represented in multiple visual areas. It is not clear to what extent the development and maintenance of this retinotopic organization in humans depend on retinal waves and/or visual experience. We examined the corticocortical receptive field organization of resting-state BOLD data in normally sighted, early blind, and anophthalmic (in which both eyes fail to develop) individuals and found that resting-state correlations between V1 and V2/V3 were retinotopically organized for all subject groups. These results show that the gross retinotopic pattern of resting-state connectivity across V1-V3 requires neither retinal waves nor visual experience to develop and persist into adulthood. SIGNIFICANCE STATEMENT Evidence from resting-state BOLD data suggests that the connections between early visual areas develop and are maintained even in the absence of retinal waves and visual experience. PMID:26354906

  20. Resting-State Retinotopic Organization in the Absence of Retinal Input and Visual Experience.

    PubMed

    Bock, Andrew S; Binda, Paola; Benson, Noah C; Bridge, Holly; Watkins, Kate E; Fine, Ione

    2015-09-01

    Early visual areas have neuronal receptive fields that form a sampling mosaic of visual space, resulting in a series of retinotopic maps in which the same region of space is represented in multiple visual areas. It is not clear to what extent the development and maintenance of this retinotopic organization in humans depend on retinal waves and/or visual experience. We examined the corticocortical receptive field organization of resting-state BOLD data in normally sighted, early blind, and anophthalmic (in which both eyes fail to develop) individuals and found that resting-state correlations between V1 and V2/V3 were retinotopically organized for all subject groups. These results show that the gross retinotopic pattern of resting-state connectivity across V1-V3 requires neither retinal waves nor visual experience to develop and persist into adulthood. Significance statement: Evidence from resting-state BOLD data suggests that the connections between early visual areas develop and are maintained even in the absence of retinal waves and visual experience. PMID:26354906

  1. Clusters of synaptic inputs on dendrites of layer 5 pyramidal cells in mouse visual cortex

    PubMed Central

    Gökçe, Onur; Bonhoeffer, Tobias; Scheuss, Volker

    2016-01-01

    The spatial organization of synaptic inputs on the dendritic tree of cortical neurons plays a major role for dendritic integration and neural computations, yet, remarkably little is known about it. We mapped the spatial organization of glutamatergic synapses between layer 5 pyramidal cells by combining optogenetics and 2-photon calcium imaging in mouse neocortical slices. To mathematically characterize the organization of inputs we developed an approach based on combinatorial analysis of the likelihoods of specific synapse arrangements. We found that the synapses of intralaminar inputs form clusters on the basal dendrites of layer 5 pyramidal cells. These clusters contain 4 to 14 synapses within ≤30 µm of dendrite. According to the spatiotemporal characteristics of synaptic summation, these numbers suggest that there will be non-linear dendritic integration of synaptic inputs during synchronous activation. DOI: http://dx.doi.org/10.7554/eLife.09222.001 PMID:27431612

  2. Online Least Squares One-Class Support Vector Machines-Based Abnormal Visual Event Detection

    PubMed Central

    Wang, Tian; Chen, Jie; Zhou, Yi; Snoussi, Hichem

    2013-01-01

    The abnormal event detection problem is an important subject in real-time video surveillance. In this paper, we propose a novel online one-class classification algorithm, online least squares one-class support vector machine (online LS-OC-SVM), combined with its sparsified version (sparse online LS-OC-SVM). LS-OC-SVM extracts a hyperplane as an optimal description of training objects in a regularized least squares sense. The online LS-OC-SVM learns a training set with a limited number of samples to provide a basic normal model, then updates the model through remaining data. In the sparse online scheme, the model complexity is controlled by the coherence criterion. The online LS-OC-SVM is adopted to handle the abnormal event detection problem. Each frame of the video is characterized by the covariance matrix descriptor encoding the moving information, then is classified into a normal or an abnormal frame. Experiments are conducted, on a two-dimensional synthetic distribution dataset and a benchmark video surveillance dataset, to demonstrate the promising results of the proposed online LS-OC-SVM method. PMID:24351629

  3. Cross-Modal Stimulus Conflict: The Behavioral Effects of Stimulus Input Timing in a Visual-Auditory Stroop Task

    PubMed Central

    Donohue, Sarah E.; Appelbaum, Lawrence G.; Park, Christina J.; Roberts, Kenneth C.; Woldorff, Marty G.

    2013-01-01

    Cross-modal processing depends strongly on the compatibility between different sensory inputs, the relative timing of their arrival to brain processing components, and on how attention is allocated. In this behavioral study, we employed a cross-modal audio-visual Stroop task in which we manipulated the within-trial stimulus-onset-asynchronies (SOAs) of the stimulus-component inputs, the grouping of the SOAs (blocked vs. random), the attended modality (auditory or visual), and the congruency of the Stroop color-word stimuli (congruent, incongruent, neutral) to assess how these factors interact within a multisensory context. One main result was that visual distractors produced larger incongruency effects on auditory targets than vice versa. Moreover, as revealed by both overall shorter response times (RTs) and relative shifts in the psychometric incongruency-effect functions, visual-information processing was faster and produced stronger and longer-lasting incongruency effects than did auditory. When attending to either modality, stimulus incongruency from the other modality interacted with SOA, yielding larger effects when the irrelevant distractor occurred prior to the attended target, but no interaction with SOA grouping. Finally, relative to neutral-stimuli, and across the wide range of the SOAs employed, congruency led to substantially more behavioral facilitation than did incongruency to interference, in contrast to findings that within-modality stimulus-compatibility effects tend to be more evenly split between facilitation and interference. In sum, the present findings reveal several key characteristics of how we process the stimulus compatibility of cross-modal sensory inputs, reflecting stimulus processing patterns that are critical for successfully navigating our complex multisensory world. PMID:23638149

  4. Electrophysiological Evidence that Abnormal Early Visual Experience Can Modify the Human Brain.

    PubMed

    Freeman, R D; Thibos, L N

    1973-06-15

    In the caption of the cover photograph for 25 May 1973, the word "below" is misplaced; it should be deleted from the first sentence, and the second sentence should read: "(Below) Same view taken through a cylindrical lens . . ." Two errors occurred in the report by Freeman and Thibos in the same issue, p. 876: in column 2, line 4, "Freeman and co-workers" should be changed to "Freeman et al." in column 3, line 44, "the visual resolution" should be changed to "visual resolution"-Ed. PMID:17743606

  5. Abnormal Attention in Autism Shown by Steady-State Visual Evoked Potentials.

    ERIC Educational Resources Information Center

    Belmonte, Matthew

    2000-01-01

    Eight males with autism were required to shift attention between rapidly flashed targets alternating between left and right visual hemifields. When targets were separated by less than 700 ms, steady-state brain electrical response in both hemispheres was augmented and background EEG decreased for rightward shifts as compared with leftward shifts.…

  6. Ventral Lateral Geniculate Input to the Medial Pons Is Necessary for Visual Eyeblink Conditioning in Rats

    ERIC Educational Resources Information Center

    Halverson, Hunter E.; Freeman, John H.

    2010-01-01

    The conditioned stimulus (CS) pathway that is necessary for visual delay eyeblink conditioning was investigated in the current study. Rats were initially given eyeblink conditioning with stimulation of the ventral nucleus of the lateral geniculate (LGNv) as the CS followed by conditioning with light and tone CSs in separate training phases.…

  7. The roles of visual expertise and visual input in the face inversion effect: behavioral and neurocomputational evidence.

    PubMed

    McCleery, Joseph P; Zhang, Lingyun; Ge, Liezhong; Wang, Zhe; Christiansen, Eric M; Lee, Kang; Cottrell, Garrison W

    2008-02-01

    Research has shown that inverting faces significantly disrupts the processing of configural information, leading to a face inversion effect. We recently used a contextual priming technique to show that the presence or absence of the face inversion effect can be determined via the top-down activation of face versus non-face processing systems [Ge, L., Wang, Z., McCleery, J., & Lee, K. (2006). Activation of face expertise and the inversion effect. Psychological Science, 17(1), 12-16]. In the current study, we replicate these findings using the same technique but under different conditions. We then extend these findings through the application of a neural network model of face and Chinese character expertise systems. Results provide support for the hypothesis that a specialized face expertise system develops through extensive training of the visual system with upright faces, and that top-down mechanisms are capable of influencing when this face expertise system is engaged. PMID:18226826

  8. The role of vestibular and support-tactile-proprioceptive inputs in visual-manual tracking

    NASA Astrophysics Data System (ADS)

    Kornilova, Ludmila; Naumov, Ivan; Glukhikh, Dmitriy; Khabarova, Ekaterina; Pavlova, Aleksandra; Ekimovskiy, Georgiy; Sagalovitch, Viktor; Smirnov, Yuriy; Kozlovskaya, Inesa

    Sensorimotor disorders in weightlessness are caused by changes of functioning of gravity-dependent systems, first of all - vestibular and support. The question arises, what’s the role and the specific contribution of the support afferentation in the development of observed disorders. To determine the role and effects of vestibular, support, tactile and proprioceptive afferentation on characteristics of visual-manual tracking (VMT) we conducted a comparative analysis of the data obtained after prolonged spaceflight and in a model of weightlessness - horizontal “dry” immersion. Altogether we examined 16 Russian cosmonauts before and after prolonged spaceflights (129-215 days) and 30 subjects who stayed in immersion bath for 5-7 days to evaluate the state of the vestibular function (VF) using videooculography and characteristics of the visual-manual tracking (VMT) using electrooculography & joystick with biological visual feedback. Evaluation of the VF has shown that both after immersion and after prolonged spaceflight there were significant decrease of the static torsional otolith-cervical-ocular reflex (OCOR) and simultaneous significant increase of the dynamic vestibular-cervical-ocular reactions (VCOR) with a revealed negative correlation between parameters of the otoliths and canals reactions, as well as significant changes in accuracy of perception of the subjective visual vertical which correlated with changes in OCOR. Analyze of the VMT has shown that significant disorders of the visual tracking (VT) occurred from the beginning of the immersion up to 3-4 day after while in cosmonauts similar but much more pronounced oculomotor disorders and significant changes from the baseline were observed up to R+9 day postflight. Significant changes of the manual tracking (MT) were revealed only for gain and occurred on 1 and 3 days in immersion while after spaceflight such changes were observed up to R+5 day postflight. We found correlation between characteristics

  9. Response variability of frontal eye field neurons modulates with sensory input and saccade preparation but not visual search salience.

    PubMed

    Purcell, Braden A; Heitz, Richard P; Cohen, Jeremiah Y; Schall, Jeffrey D

    2012-11-01

    Discharge rate modulation of frontal eye field (FEF) neurons has been identified with a representation of visual search salience (physical conspicuity and behavioral relevance) and saccade preparation. We tested whether salience or saccade preparation are evident in the trial-to-trial variability of discharge rate. We quantified response variability via the Fano factor in FEF neurons recorded in monkeys performing efficient and inefficient visual search tasks. Response variability declined following stimulus presentation in most neurons, but despite clear discharge rate modulation, variability did not change with target salience. Instead, we found that response variability was modulated by stimulus luminance and the number of items in the visual field independently of attentional demands. Response variability declined to a minimum before saccade initiation, and presaccadic response variability was directionally tuned. In addition, response variability was correlated with the response time of memory-guided saccades. These results indicate that the trial-by-trial response variability of FEF neurons reflects saccade preparation and the strength of sensory input, but not visual search salience or attentional allocation. PMID:22956785

  10. Nonthermal sensory input and altered human thermoregulation: effects of visual information depicting hot or cold environments.

    PubMed

    Takakura, Jun'ya; Nishimura, Takayuki; Choi, Damee; Egashira, Yuka; Watanuki, Shigeki

    2015-10-01

    A recent study showed that thermoregulatory-like cardiovascular responses can be invoked simply by exposure to visual information, even though the thermal environments are neutral and unchanged. However, it was not clear how such responses affect actual human body temperature regulation. We investigated whether such visually invoked physiological responses can substantively affect human core body temperature in a thermally challenging cold environment. Participants comprised 13 graduate or undergraduate students viewing different video images containing hot, cold, or no scenery, while room temperature was gradually lowered from 28 to 16 °C over 80 min. Rectal temperature, mean skin temperature, core to skin temperature gradient, and oxygen consumption were measured during the experiment. Rectal temperature was significantly lower when hot video images were presented compared to when control video images were presented. Oxygen consumption was comparable among all video images, but core to skin temperature gradient was significantly lower when hot video images were presented. This result suggests that visual information, even in the absence of thermal energy, can affect human thermodynamics and core body temperature. PMID:25609478

  11. Nonthermal sensory input and altered human thermoregulation: effects of visual information depicting hot or cold environments

    NASA Astrophysics Data System (ADS)

    Takakura, Jun'ya; Nishimura, Takayuki; Choi, Damee; Egashira, Yuka; Watanuki, Shigeki

    2015-10-01

    A recent study showed that thermoregulatory-like cardiovascular responses can be invoked simply by exposure to visual information, even though the thermal environments are neutral and unchanged. However, it was not clear how such responses affect actual human body temperature regulation. We investigated whether such visually invoked physiological responses can substantively affect human core body temperature in a thermally challenging cold environment. Participants comprised 13 graduate or undergraduate students viewing different video images containing hot, cold, or no scenery, while room temperature was gradually lowered from 28 to 16 °C over 80 min. Rectal temperature, mean skin temperature, core to skin temperature gradient, and oxygen consumption were measured during the experiment. Rectal temperature was significantly lower when hot video images were presented compared to when control video images were presented. Oxygen consumption was comparable among all video images, but core to skin temperature gradient was significantly lower when hot video images were presented. This result suggests that visual information, even in the absence of thermal energy, can affect human thermodynamics and core body temperature.

  12. Improving postural control through integration of sensory inputs and visual biofeedback.

    PubMed

    Fuller, K; Huber, L

    1995-01-01

    Postural control is an essential component to be considered in the rehabilitation of stroke survivors. This article attempts to provide the clinician with terminology and frameworks for classification in order to provide a more focused intervention. There is a comparison of some of the available assessments of impairment and disability. Treatment emphasizing the specific use of visual biofeedback to improve postural control is described. Control of the sensory environment during treatment to challenge a patient's ability to integrate available sensory information to perform balance activities is described. A case study incorporating treatment ideas is included. PMID:27619900

  13. Abnormal visual-evoked potentials in leukemic children after cranial radiation

    SciTech Connect

    Russo, A.; Tomarchio, S.; Pero, G.; Consoli, G.; Marina, R.; Rizzari, C.; Schiliro, G.

    1985-01-01

    Visual-evoked potentials (VEPs) were studied in 55 asymptomatic children with leukemia or solid tumors in remission in order to detect subclinical demyelination of the optic pathway after CNS prophylaxis. In group I (11 patients with ALL studied prospectively), VEP latency was increased in ten after cranial radiation (CR) as compared with previous values. Group II (18 patients with ALL in maintenance) and group III (16 patients with ALL off therapy) were studied retrospectively and VEP latency was found above normal limits in 33 and 31%, respectively. In group IV (four patients with solid tumors and six with leukemia, all of whom received no CR), VEP latency was normal despite periodical intrathecal methotrexate administrations to five of them. The authors conclude that CR determines a slowing of conduction on VEP test, probably due to demyelination of the optic pathway, in a high proportion of patients. The future clinical significance of these findings must be established throughout a prolonged follow-up period.

  14. Top-down inputs enhance orientation selectivity in neurons of the primary visual cortex during perceptual learning.

    PubMed

    Moldakarimov, Samat; Bazhenov, Maxim; Sejnowski, Terrence J

    2014-08-01

    Perceptual learning has been used to probe the mechanisms of cortical plasticity in the adult brain. Feedback projections are ubiquitous in the cortex, but little is known about their role in cortical plasticity. Here we explore the hypothesis that learning visual orientation discrimination involves learning-dependent plasticity of top-down feedback inputs from higher cortical areas, serving a different function from plasticity due to changes in recurrent connections within a cortical area. In a Hodgkin-Huxley-based spiking neural network model of visual cortex, we show that modulation of feedback inputs to V1 from higher cortical areas results in shunting inhibition in V1 neurons, which changes the response properties of V1 neurons. The orientation selectivity of V1 neurons is enhanced without changing orientation preference, preserving the topographic organizations in V1. These results provide new insights to the mechanisms of plasticity in the adult brain, reconciling apparently inconsistent experiments and providing a new hypothesis for a functional role of the feedback connections. PMID:25121603

  15. 3D PATTERN OF BRAIN ABNORMALITIES IN WILLIAMS SYNDROME VISUALIZED USING TENSOR-BASED MORPHOMETRY

    PubMed Central

    Chiang, Ming-Chang; Reiss, Allan L.; Lee, Agatha D.; Bellugi, Ursula; Galaburda, Albert M.; Korenberg, Julie R.; Mills, Debra L.; Toga, Arthur W.; Thompson, Paul M.

    2009-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder associated with deletion of ~20 contiguous genes in chromosome band 7q11.23. Individuals with WS exhibit mild to moderate mental retardation, but are relatively more proficient in specific language and musical abilities. We used tensor-based morphometry (TBM) to visualize the complex pattern of gray/white matter reductions in WS, based on fluid registration of structural brain images. Methods 3D T1-weighted brain MRIs of 41 WS subjects (age: 29.2±9.2SD years; 23F/18M) and 39 age-matched healthy controls (age: 27.5±7.4 years; 23F/16M) were fluidly registered to a minimum deformation target. Fine-scale volumetric differences were mapped between diagnostic groups. Local regions were identified where regional structure volumes were associated with diagnosis, and with intelligence quotient (IQ) scores. Brain asymmetry was also mapped and compared between diagnostic groups. Results WS subjects exhibited widely distributed brain volume reductions (~10–15% reduction; P < 0.0002, permutation test). After adjusting for total brain volume, the frontal lobes, anterior cingulate, superior temporal gyrus, amygdala, fusiform gyrus and cerebellum were found to be relatively preserved in WS, but parietal and occipital lobes, thalamus and basal ganglia, and midbrain were disproportionally decreased in volume (P < 0.0002). These regional volumes also correlated positively with performance IQ in adult WS subjects (age ≥ 30 years, P = 0.038). Conclusion TBM facilitates 3D visualization of brain volume reductions in WS. Reduced parietal/occipital volumes may be associated with visuospatial deficits in WS. By contrast, frontal lobes, amygdala, and cingulate gyrus are relatively preserved or even enlarged, consistent with unusual affect regulation and language production in WS. PMID:17512756

  16. Multiple spectral inputs improve motion discrimination in the Drosophila visual system.

    PubMed

    Wardill, Trevor J; List, Olivier; Li, Xiaofeng; Dongre, Sidhartha; McCulloch, Marie; Ting, Chun-Yuan; O'Kane, Cahir J; Tang, Shiming; Lee, Chi-Hon; Hardie, Roger C; Juusola, Mikko

    2012-05-18

    Color and motion information are thought to be channeled through separate neural pathways, but it remains unclear whether and how these pathways interact to improve motion perception. In insects, such as Drosophila, it has long been believed that motion information is fed exclusively by one spectral class of photoreceptor, so-called R1 to R6 cells; whereas R7 and R8 photoreceptors, which exist in multiple spectral classes, subserve color vision. Here, we report that R7 and R8 also contribute to the motion pathway. By using electrophysiological, optical, and behavioral assays, we found that R7/R8 information converge with and shape the motion pathway output, explaining flies' broadly tuned optomotor behavior by its composite responses. Our results demonstrate that inputs from photoreceptors of different spectral sensitivities improve motion discrimination, increasing robustness of perception. PMID:22605779

  17. Correlations between vocal input and visual response apparently enhance presence in a virtual environment.

    PubMed

    Groenegress, Christoph; Thomsen, Mette Ramsgard; Slater, Mel

    2009-08-01

    Abstract This work investigates novel alternative means of interaction in a virtual environment (VE). We analyze whether humans can remap established body functions to learn to interact with digital information in an environment that is cross-sensory by nature and uses vocal utterances in order to influence (abstract) virtual objects. We thus establish a correlation among learning, control of the interface, and the perceived sense of presence in the VE. The application enables intuitive interaction by mapping actions (the prosodic aspects of the human voice) to a certain response (i.e., visualization). A series of single-user and multiuser studies shows that users can gain control of the intuitive interface and learn to adapt to new and previously unseen tasks in VEs. Despite the abstract nature of the presented environment, presence scores were generally very high. PMID:19630585

  18. Face to face: visual scanpath evidence for abnormal processing of facial expressions in social phobia.

    PubMed

    Horley, Kaye; Williams, Leanne M; Gonsalvez, Craig; Gordon, Evian

    2004-06-30

    Cognitive models of social phobia propose that cognitive biases and fears regarding negative evaluation by others result in preferential attention to interpersonal sources of threat. These fears may account for the hypervigilance and avoidance of eye contact commonly reported by clinicians. This study provides the first objective examination of threat-related processing in social phobia. It was predicted that hyperscanning (hypervigilance) and eye avoidance would be most apparent in social phobia for overt expressions of threat. An infrared corneal reflection technique was used to record visual scanpaths in response to angry, sad, and happy vs. neutral facial expressions. Twenty-two subjects with social phobia were compared with age- and sex-matched normal controls. As predicted, social phobia subjects displayed hyperscanning, (increased scanpath length) and avoidance (reduced foveal fixations) of the eyes, particularly evident for angry faces. The results could not be explained by either medication or co-morbid depression. These findings are consistent with theories emphasising the role of information processing biases in social phobia, and show promise in the application to treatment evaluation in this disorder. PMID:15261704

  19. Object-based attention benefits reveal selective abnormalities of visual integration in autism.

    PubMed

    Falter, Christine M; Grant, Kate C Plaisted; Davis, Greg

    2010-06-01

    A pervasive integration deficit could provide a powerful and elegant account of cognitive processing in autism spectrum disorders (ASD). However, in the case of visual Gestalt grouping, typically assessed by tasks that require participants explicitly to introspect on their own grouping perception, clear evidence for such a deficit remains elusive. To resolve this issue, we adopt an index of Gestalt grouping from the object-based attention literature that does not require participants to assess their own grouping perception. Children with ASD and mental- and chronological-age matched typically developing children (TD) performed speeded orientation discriminations of two diagonal lines. The lines were superimposed on circles that were either grouped together or segmented on the basis of color, proximity or these two dimensions in competition. The magnitude of performance benefits evident for grouped circles, relative to ungrouped circles, provided an index of grouping under various conditions. Children with ASD showed comparable grouping by proximity to the TD group, but reduced grouping by similarity. ASD seems characterized by a selective bias away from grouping by similarity combined with typical levels of grouping by proximity, rather than by a pervasive integration deficit. PMID:20578070

  20. Abnormal brain activation and connectivity to standardized disorder-related visual scenes in social anxiety disorder.

    PubMed

    Heitmann, Carina Yvonne; Feldker, Katharina; Neumeister, Paula; Zepp, Britta Maria; Peterburs, Jutta; Zwitserlood, Pienie; Straube, Thomas

    2016-04-01

    Our understanding of altered emotional processing in social anxiety disorder (SAD) is hampered by a heterogeneity of findings, which is probably due to the vastly different methods and materials used so far. This is why the present functional magnetic resonance imaging (fMRI) study investigated immediate disorder-related threat processing in 30 SAD patients and 30 healthy controls (HC) with a novel, standardized set of highly ecologically valid, disorder-related complex visual scenes. SAD patients rated disorder-related as compared with neutral scenes as more unpleasant, arousing and anxiety-inducing than HC. On the neural level, disorder-related as compared with neutral scenes evoked differential responses in SAD patients in a widespread emotion processing network including (para-)limbic structures (e.g. amygdala, insula, thalamus, globus pallidus) and cortical regions (e.g. dorsomedial prefrontal cortex (dmPFC), posterior cingulate cortex (PCC), and precuneus). Functional connectivity analysis yielded an altered interplay between PCC/precuneus and paralimbic (insula) as well as cortical regions (dmPFC, precuneus) in SAD patients, which emphasizes a central role for PCC/precuneus in disorder-related scene processing. Hyperconnectivity of globus pallidus with amygdala, anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) additionally underlines the relevance of this region in socially anxious threat processing. Our findings stress the importance of specific disorder-related stimuli for the investigation of altered emotion processing in SAD. Disorder-related threat processing in SAD reveals anomalies at multiple stages of emotion processing which may be linked to increased anxiety and to dysfunctionally elevated levels of self-referential processing reported in previous studies. PMID:26806013

  1. Effect of visual input on normalized standing stability in subjects with recurrent low back pain.

    PubMed

    Lee, Dongchul C; Ham, Yong Woon; Sung, Paul S

    2012-07-01

    Although a number of studies have evaluated kinematic stability changes in subjects with low back pain (LBP), the combined sensitivity of normalized standing stability from the ground force and kinematic rotational angle of the body segment were not carefully examined for postural responses. The purpose of this study was to evaluate normalized standing stability in subjects with and without recurrent LBP while they stood quietly with the tested foot parallel to the other lower extremity at hip width. The subjects were then instructed to stand freely on one leg for 25 s with the contra lateral hip flexed 90° based on dominance side (dominant leg vs. non-dominant lower extremity) and visual condition (eyes open vs. eyes closed). A total of 42 subjects (27 subjects without LBP and 15 subjects with LBP) participated in the study. The dominant leg standing stability was significantly different during the eyes closed condition (0.68±0.30 for control vs. 0.37±0.32 for LBP, T=-3.23, p=0.002) compared to the eyes open condition. The standing kinematic stability, especially of the dominant thigh, was greater in the control subjects than in the subjects with LBP (T=-2.43, p=0.02). This sensitive detection of kinematic imbalance with postural stability is important for effective rehabilitation strategies and to understanding compensatory mechanisms in subjects with recurrent LBP. PMID:22717729

  2. Spatial vision in insects is facilitated by shaping the dynamics of visual input through behavioral action

    PubMed Central

    Egelhaaf, Martin; Boeddeker, Norbert; Kern, Roland; Kurtz, Rafael; Lindemann, Jens P.

    2012-01-01

    Insects such as flies or bees, with their miniature brains, are able to control highly aerobatic flight maneuvres and to solve spatial vision tasks, such as avoiding collisions with obstacles, landing on objects, or even localizing a previously learnt inconspicuous goal on the basis of environmental cues. With regard to solving such spatial tasks, these insects still outperform man-made autonomous flying systems. To accomplish their extraordinary performance, flies and bees have been shown by their characteristic behavioral actions to actively shape the dynamics of the image flow on their eyes (“optic flow”). The neural processing of information about the spatial layout of the environment is greatly facilitated by segregating the rotational from the translational optic flow component through a saccadic flight and gaze strategy. This active vision strategy thus enables the nervous system to solve apparently complex spatial vision tasks in a particularly efficient and parsimonious way. The key idea of this review is that biological agents, such as flies or bees, acquire at least part of their strength as autonomous systems through active interactions with their environment and not by simply processing passively gained information about the world. These agent-environment interactions lead to adaptive behavior in surroundings of a wide range of complexity. Animals with even tiny brains, such as insects, are capable of performing extraordinarily well in their behavioral contexts by making optimal use of the closed action–perception loop. Model simulations and robotic implementations show that the smart biological mechanisms of motion computation and visually-guided flight control might be helpful to find technical solutions, for example, when designing micro air vehicles carrying a miniaturized, low-weight on-board processor. PMID:23269913

  3. Visualization study of nucleate pool boiling of liquid nitrogen with quasi-steady heat input

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaobin; Chen, Jianye; Xiong, Wei; Jin, Tao

    2015-12-01

    A visualization experimental device has been built to investigate the bubble behaviors in the nucleate pool boiling of cryogenic fluids at atmospheric pressure. The general morphologies of the bubbles are analyzed based on the captured films using a high-speed camera. The bubble behaviors leaving the wall at different heat flux can be divided into three regimes (low heat flux regime, fully developed nucleate boiling regime and intermediate regime) according to the availability of bubble parameters. In the low heat flux regime, the bubble is discrete and the interactive effects are ignorable. In the fully developed nucleate boiling regime close to CHF, the bubbles depart in the form of bubble cluster with a neck. In the intermediate regime, the interactive effect between the bubbles is significant and the bubbles follow a random pattern neither discretely nor as cluster neck. The information about the bubble departure diameter, the detachment frequency and the number density of activated sites are specially investigated. These data are used to evaluate the existing semi-empirical correlations widely applied to either the room-temperature or cryogenic fluids. It is found that the Kim's correlation for the departure diameter predicts a satisfactory agreement with the experimental results in the isolated bubble regime. For the predictions of the detachment frequency, the correlation by Katto and Yokoya is recommended after comparison. The relation between the diameter and frequency can also be well determined by the correlation proposed by Mcfadden et al. The number density of active sites for liquid nitrogen still can be considered to be linearly proportional to ΔTm as it is for water, except that the exponent absolute m is much smaller.

  4. Increased apoptosis and abnormal visual behavior by histone modifications with exposure to para-xylene in developing Xenopus.

    PubMed

    Gao, Juanmei; Ruan, Hangze; Qi, Xianjie; Guo, Xia; Zheng, Jingna; Liu, Cong; Fang, Yanxiao; Huang, Minjiao; Xu, Miao; Shen, Wanhua

    2016-09-01

    Xylene and its derivatives are raw materials widely used in industry and known to be toxic to animals. However, the mechanism underlying the neurotoxicity of para-xylene (PX) to the central nervous system (CNS) in vivo is less clear. Here, we exposed Xenopus laevis tadpoles to sub-lethal concentrations of PX during the critical period of brain development to determine the effects of PX on Xenopus development and visual behavior. We found that the abnormality rate was significantly increased with exposure to increasing concentrations of PX. In particular, the number of apoptotic cells in the optic tectum was dramatically increased with exposure to PX at 2mM. Long-term PX exposure also resulted in significant deficits in visually guided avoidance behavior. Strikingly, co-incubation with PX and d-glucuronolactone (GA) decreased the number of apoptotic cells and rescued the avoidance behavior. Furthermore, we found that the acetylation of H4K12 (H4K12ac) and the dimethylation of H3K9 (H3K9me2) in the optic tectum were significantly increased in PX-treated animals, and these effects were suppressed by GA treatment. In particular, the increase in apoptotic cells in PX-treated brains was also inhibited by GA treatment. These effects indicate that epigenetic regulation plays a key role in PX-induced apoptosis and animal behavior. In an effort to characterize the neurotoxic effects of PX on brain development and behavior, these results suggest that the neurotoxicity of PX requires further evaluation regarding the safety of commercial and industrial uses. PMID:27343828

  5. Visual inputs to the mushroom body calyces of the whirligig beetle Dineutus sublineatus: modality switching in an insect.

    PubMed

    Lin, Chan; Strausfeld, Nicholas J

    2012-08-15

    The mushroom bodies are prominent lobed centers in the forebrain, or protocerebrum, of most insects. Previous studies on mushroom bodies have focused on higher olfactory processing, including olfactory-based learning and memory. Anatomical studies provide strong support that in terrestrial insects with mushroom bodies, the primary input region, or calyces, are predominantly supplied by olfactory projection neurons from the antennal lobe glomeruli. In aquatic species that generally lack antennal lobes, the calyces are vestigial or absent. Here we report an exception to this in the whirligig beetle Dineutus sublineatus (Coleoptera: Gyrinidae). This aquatic species lives on water and is equipped with two separate pairs of compound eyes, one pair viewing above and one viewing below the water surface. As in other aquatic insects, the whirligig beetle lacks antennal lobes, but unlike other aquatic insects its mushroom bodies possess robust calyces. Golgi impregnations and fluorescent tracer injections revealed that the calyces are exclusively supplied by visual neurons from the medulla of the dorsal eye optic lobes. No other sensory inputs reach the calyces, thereby showing a complete switch of calyx modality from olfaction to vision. Potential functions of the mushroom bodies of D. sublineatus are discussed in the context of the behavioral ecology of whirligig beetles. PMID:22684942

  6. Gap Effect Abnormalities during a Visually Guided Pro-Saccade Task in Children with Attention Deficit Hyperactivity Disorder

    PubMed Central

    Taniike, Masako; Mohri, Ikuko; Kobashi, Syoji; Tachibana, Masaya; Kobayashi, Yasushi; Kitamura, Yuri

    2015-01-01

    Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that starts in early childhood and has a comprehensive impact on psychosocial activity and education as well as general health across the lifespan. Despite its prevalence, the current diagnostic criteria for ADHD are debated. Saccadic eye movements are easy to quantify and may be a quantitative biomarker for a wide variety of neurological and psychiatric disorders, including ADHD. The goal of this study was to examine whether children with ADHD exhibit abnormalities during a visually guided pro-saccadic eye-movement and to clarify the neurophysiological mechanisms associated with their behavioral impairments. Thirty-seven children with ADHD (aged 5–11 years) and 88 typically developing (TD) children (aged 5–11 years) were asked to perform a simple saccadic eye-movement task in which step and gap conditions were randomly interleaved. We evaluated the gap effect, which is the difference in the reaction time between the two conditions. Children with ADHD had a significantly longer reaction time than TD children (p < 0.01) and the gap effect was markedly attenuated (p < 0.01). These results suggest that the measurement of saccadic eye movements may provide a novel method for evaluating the behavioral symptoms and clinical features of ADHD, and that the gap effect is a potential biomarker for the diagnosis of ADHD in early childhood. PMID:26018057

  7. Static and dynamic posture control in postlingual cochlear implanted patients: effects of dual-tasking, visual and auditory inputs suppression

    PubMed Central

    Bernard-Demanze, Laurence; Léonard, Jacques; Dumitrescu, Michel; Meller, Renaud; Magnan, Jacques; Lacour, Michel

    2014-01-01

    Posture control is based on central integration of multisensory inputs, and on internal representation of body orientation in space. This multisensory feedback regulates posture control and continuously updates the internal model of body's position which in turn forwards motor commands adapted to the environmental context and constraints. The peripheral localization of the vestibular system, close to the cochlea, makes vestibular damage possible following cochlear implant (CI) surgery. Impaired vestibular function in CI patients, if any, may have a strong impact on posture stability. The simple postural task of quiet standing is generally paired with cognitive activity in most day life conditions, leading therefore to competition for attentional resources in dual-tasking, and increased risk of fall particularly in patients with impaired vestibular function. This study was aimed at evaluating the effects of postlingual cochlear implantation on posture control in adult deaf patients. Possible impairment of vestibular function was assessed by comparing the postural performance of patients to that of age-matched healthy subjects during a simple postural task performed in static (stable platform) and dynamic (platform in translation) conditions, and during dual-tasking with a visual or auditory memory task. Postural tests were done in eyes open (EO) and eyes closed (EC) conditions, with the CI activated (ON) or not (OFF). Results showed that the postural performance of the CI patients strongly differed from the controls, mainly in the EC condition. The CI patients showed significantly reduced limits of stability and increased postural instability in static conditions. In dynamic conditions, they spent considerably more energy to maintain equilibrium, and their head was stabilized neither in space nor on trunk: they behaved dynamically without vision like an inverted pendulum while the controls showed a whole body rigidification strategy. Hearing (prosthesis on) as well

  8. Visualization of Ca2+ Filling Mechanisms upon Synaptic Inputs in the Endoplasmic Reticulum of Cerebellar Purkinje Cells.

    PubMed

    Okubo, Yohei; Suzuki, Junji; Kanemaru, Kazunori; Nakamura, Naotoshi; Shibata, Tatsuo; Iino, Masamitsu

    2015-12-01

    The endoplasmic reticulum (ER) plays crucial roles in intracellular Ca(2+) signaling, serving as both a source and sink of Ca(2+), and regulating a variety of physiological and pathophysiological events in neurons in the brain. However, spatiotemporal Ca(2+) dynamics within the ER in central neurons remain to be characterized. In this study, we visualized synaptic activity-dependent ER Ca(2+) dynamics in mouse cerebellar Purkinje cells (PCs) using an ER-targeted genetically encoded Ca(2+) indicator, G-CEPIA1er. We used brief parallel fiber stimulation to induce a local decrease in the ER luminal Ca(2+) concentration ([Ca(2+)]ER) in dendrites and spines. In this experimental system, the recovery of [Ca(2+)]ER takes several seconds, and recovery half-time depends on the extent of ER Ca(2+) depletion. By combining imaging analysis and numerical simulation, we show that the intraluminal diffusion of Ca(2+), rather than Ca(2+) reuptake, is the dominant mechanism for the replenishment of the local [Ca(2+)]ER depletion immediately following the stimulation. In spines, the ER filled almost simultaneously with parent dendrites, suggesting that the ER within the spine neck does not represent a significant barrier to Ca(2+) diffusion. Furthermore, we found that repetitive climbing fiber stimulation, which induces cytosolic Ca(2+) spikes in PCs, cumulatively increased [Ca(2+)]ER. These results indicate that the neuronal ER functions both as an intracellular tunnel to redistribute stored Ca(2+) within the neurons, and as a leaky integrator of Ca(2+) spike-inducing synaptic inputs. PMID:26631466

  9. Bit-depth extension using spatiotemporal microdither based on models of the equivalent input noise of the visual system

    NASA Astrophysics Data System (ADS)

    Daly, Scott J.; Feng, Xiaofan

    2003-01-01

    Continuous tone, or "contone", imagery usually has 24 bits/pixel as a minimum, with eight bits each for the three primaries in typical displays. However, lower-cost displays constrain this number because of various system limitations. Conversely, high quality displays seek to achieve 9-10 bits/pixel/color, though there may be system bottlenecks limited at 8. The two main artifacts from reduced bit-depth are contouring and loss of amplitude detail; these can be prevented by dithering the image prior to these bit-depth losses. Early work in this area includes Roberts" noise modulation technique, Mista"s blue noise mask, Tyler"s technique of bit-stealing, and Mulligan"s use of the visual system"s spatiotemporal properties for spatiotemporal dithering. However, most halftoning/dithering work was primarily directed to displays at the lower end of bits/pixel (e.g., 1 bit as in halftoning) and higher ppi. Like Tyler, we approach the problem from the higher end of bits/pixel/color, say 6-8, and use available high frequency color content to generate even higher luminance amplitude resolution. Bit-depth extension with a high starting bit-depth (and often lower spatial resolution) changes the game substantially from halftoning experience. For example, complex algorithms like error diffusion and annealing are not needed, just the simple addition of noise. Instead of a spatial dither, it is better to use an amplitude dither, termed microdither by Pappas. We have looked at methods of generating the highest invisible opponent color spatiotemporal noise and other patterns, and have used Ahumada"s concept of equivalent input noise to guide our work. This paper will report on techniques and observations made in achieving contone quality on ~100 ppi 6 bits/pixel/color LCD displays with no visible dither patterns, noise, contours, or loss of amplitude detail at viewing distances as close as the near focus limit (~120 mm). These include the interaction of display nonlinearities and

  10. Effects of Normal and Abnormal Visual Experience on the Development of Opposing Aftereffects for Upright and Inverted Faces

    ERIC Educational Resources Information Center

    Robbins, Rachel A.; Maurer, Daphne; Hatry, Alexandra; Anzures, Gizelle; Mondloch, Catherine J.

    2012-01-01

    We used opposing figural aftereffects to investigate whether there are at least partially separable representations of upright and inverted faces in patients who missed early visual experience because of bilateral congenital cataracts (mean age at test 19.5 years). Visually normal adults and 10-year-olds were tested for comparison. Adults showed…

  11. Infant Face Preferences after Binocular Visual Deprivation

    ERIC Educational Resources Information Center

    Mondloch, Catherine J.; Lewis, Terri L.; Levin, Alex V.; Maurer, Daphne

    2013-01-01

    Early visual deprivation impairs some, but not all, aspects of face perception. We investigated the possible developmental roots of later abnormalities by using a face detection task to test infants treated for bilateral congenital cataract within 1 hour of their first focused visual input. The seven patients were between 5 and 12 weeks old…

  12. Neuron analysis of visual perception

    NASA Technical Reports Server (NTRS)

    Chow, K. L.

    1980-01-01

    The receptive fields of single cells in the visual system of cat and squirrel monkey were studied investigating the vestibular input affecting the cells, and the cell's responses during visual discrimination learning process. The receptive field characteristics of the rabbit visual system, its normal development, its abnormal development following visual deprivation, and on the structural and functional re-organization of the visual system following neo-natal and prenatal surgery were also studied. The results of each individual part of each investigation are detailed.

  13. Abnormal Brain Activation in Neurofibromatosis Type 1: A Link between Visual Processing and the Default Mode Network

    PubMed Central

    Violante, Inês R.; Ribeiro, Maria J.; Cunha, Gil; Bernardino, Inês; Duarte, João V.; Ramos, Fabiana; Saraiva, Jorge; Silva, Eduardo; Castelo-Branco, Miguel

    2012-01-01

    Neurofibromatosis type 1 (NF1) is one of the most common single gene disorders affecting the human nervous system with a high incidence of cognitive deficits, particularly visuospatial. Nevertheless, neurophysiological alterations in low-level visual processing that could be relevant to explain the cognitive phenotype are poorly understood. Here we used functional magnetic resonance imaging (fMRI) to study early cortical visual pathways in children and adults with NF1. We employed two distinct stimulus types differing in contrast and spatial and temporal frequencies to evoke relatively different activation of the magnocellular (M) and parvocellular (P) pathways. Hemodynamic responses were investigated in retinotopically-defined regions V1, V2 and V3 and then over the acquired cortical volume. Relative to matched control subjects, patients with NF1 showed deficient activation of the low-level visual cortex to both stimulus types. Importantly, this finding was observed for children and adults with NF1, indicating that low-level visual processing deficits do not ameliorate with age. Moreover, only during M-biased stimulation patients with NF1 failed to deactivate or even activated anterior and posterior midline regions of the default mode network. The observation that the magnocellular visual pathway is impaired in NF1 in early visual processing and is specifically associated with a deficient deactivation of the default mode network may provide a neural explanation for high-order cognitive deficits present in NF1, particularly visuospatial and attentional. A link between magnocellular and default mode network processing may generalize to neuropsychiatric disorders where such deficits have been separately identified. PMID:22723888

  14. The Rubber Hand Illusion in Children with Autism Spectrum Disorders: Delayed Influence of Combined Tactile and Visual Input on Proprioception

    ERIC Educational Resources Information Center

    Cascio, Carissa J.; Foss-Feig, Jennifer H.; Burnette, Courtney P.; Heacock, Jessica L.; Cosby, Akua A.

    2012-01-01

    In the rubber hand illusion, perceived hand ownership can be transferred to a rubber hand after synchronous visual and tactile stimulation. Perceived body ownership and self-other relation are foundational for development of self-awareness, imitation, and empathy, which are all affected in autism spectrum disorders (ASD). We examined the rubber…

  15. Visual scanpath abnormalities in 22q11.2 deletion syndrome: is this a face specific deficit?

    PubMed

    McCabe, Kathryn; Rich, Dominique; Loughland, Carmel Maree; Schall, Ulrich; Campbell, Linda Elisabet

    2011-09-30

    People with 22q11.2 deletion syndrome (22q11DS) have deficits in face emotion recognition. However, it is not known whether this is a deficit specific to faces, or represents maladaptive information processing strategies to complex stimuli in general. This study examined the specificity of face emotion processing deficits in 22q11DS by exploring recognition accuracy and visual scanpath performance to a Faces task compared to a Weather Scene task. Seventeen adolescents with 22q11DS (11=females, age=17.4) and 18 healthy controls (11=females, age=17.7) participated in the study. People with 22q11DS displayed an overall impoverished scanning strategy to face and weather stimuli alike, resulting in poorer accuracy across all stimuli for the 22q11DS participants compared to controls. While the control subjects altered their information processing in response to faces, a similar change was not present in the 22q11DS group indicating different visual scanpath strategies to identify category within each of the tasks, of which faces appear to represent a particularly difficult subcategory. To conclude, while this study indicates that people with 22q11DS have a general visual processing deficit, the lack of strategic change between tasks suggest that the 22q11DS group did not adapt to the change in stimuli content as well as the controls, indicative of cognitive inflexibility rather than a face specific deficit. PMID:21831452

  16. Abnormal development of sensory-motor, visual temporal and parahippocampal cortex in children with learning disabilities and borderline intellectual functioning

    PubMed Central

    Baglio, Francesca; Cabinio, Monia; Ricci, Cristian; Baglio, Gisella; Lipari, Susanna; Griffanti, Ludovica; Preti, Maria G.; Nemni, Raffaello; Clerici, Mario; Zanette, Michela; Blasi, Valeria

    2014-01-01

    Borderline intellectual functioning (BIF) is a condition characterized by an intelligence quotient (IQ) between 70 and 85. BIF children present with cognitive, motor, social, and adaptive limitations that result in learning disabilities and are more likely to develop psychiatric disorders later in life. The aim of this study was to investigate brain morphometry and its relation to IQ level in BIF children. Thirteen children with BIF and 14 age- and sex-matched typically developing (TD) children were enrolled. All children underwent a full IQ assessment (WISC-III scale) and a magnetic resonance (MR) examination including conventional sequences to assess brain structural abnormalities and high resolution 3D images for voxel-based morphometry analysis. To investigate to what extent the group influenced gray matter (GM) volumes, both univariate and multivariate generalized linear model analysis of variance were used, and the varimax factor analysis was used to explore variable correlations and clusters among subjects. Results showed that BIF children, compared to controls have increased regional GM volume in bilateral sensorimotor and right posterior temporal cortices and decreased GM volume in the right parahippocampal gyrus. GM volumes were highly correlated with IQ indices. The present work is a case study of a group of BIF children showing that BIF is associated with abnormal cortical development in brain areas that have a pivotal role in motor, learning, and behavioral processes. Our findings, although allowing for little generalization to the general population, contribute to the very limited knowledge in this field. Future longitudinal MR studies will be useful in verifying whether cortical features can be modified over time even in association with rehabilitative intervention. PMID:25360097

  17. Combination of blood oxygen level–dependent functional magnetic resonance imaging and visual evoked potential recordings for abnormal visual cortex in two types of amblyopia

    PubMed Central

    Wang, Xinmei; Cui, Dongmei; Zheng, Ling; Yang, Xiao; Yang, Hui

    2012-01-01

    Purpose To elucidate the different neuromechanisms of subjects with strabismic and anisometropic amblyopia compared with normal vision subjects using blood oxygen level–dependent functional magnetic resonance imaging (BOLD-fMRI) and pattern-reversal visual evoked potential (PR-VEP). Methods Fifty-three subjects, age range seven to 12 years, diagnosed with strabismic amblyopia (17 cases), anisometropic amblyopia (20 cases), and normal vision (16 cases), were examined using the BOLD-fMRI and PR-VEP of UTAS-E3000 techniques. Cortical activation by binocular viewing of reversal checkerboard patterns was examined in terms of the calcarine region of interest (ROI)-based and spatial frequency–dependent analysis. The correlation of cortical activation in fMRI and the P100 amplitude in VEP were analyzed using the SPSS 12.0 software package. Results In the BOLD-fMRI procedure, reduced areas and decreased activation levels were found in Brodmann area (BA) 17 and other extrastriate areas in subjects with amblyopia compared with the normal vision group. In general, the reduced areas mainly resided in the striate visual cortex in subjects with anisometropic amblyopia. In subjects with strabismic amblyopia, a more significant cortical impairment was found in bilateral BA 18 and BA 19 than that in subjects with anisometropic amblyopia. The activation by high-spatial-frequency stimuli was reduced in bilateral BA 18 and 19 as well as BA 17 in subjects with anisometropic amblyopia, whereas the activation was mainly reduced in BA 18 and BA 19 in subjects with strabismic amblyopia. These findings were further confirmed by the ROI-based analysis of BA 17. During spatial frequency–dependent VEP detection, subjects with anisometropic amblyopia had reduced sensitivity for high spatial frequency compared to subjects with strabismic amblyopia. The cortical activation in fMRI with the calcarine ROI-based analysis of BA 17 was significantly correlated with the P100 amplitude in VEP

  18. Gait characteristics of patients with phobic postural vertigo: effects of fear of falling, attention, and visual input.

    PubMed

    Schniepp, Roman; Wuehr, Max; Huth, Sabrina; Pradhan, Cauchy; Brandt, Thomas; Jahn, Klaus

    2014-04-01

    Phobic postural vertigo (PPV) is the most common cause of chronic dizziness in middle-aged patients. Many patients report symptoms involving gait. We investigated the gait performance and its relationship to the fear of falling and attention of PPV patients in a prospective study of 24 patients with PPV and 24 healthy subjects (HS) using a pressure-sensitive mat (GAITRite(®)). Subjects walked at three different speeds (slow, preferred, fast), both during cognitive dual tasks (DTc) and with eyes closed (EC). Falls efficacy and balance confidence were rated by the Falls Efficacy Scale-International (FES-I) and the Activities-specific Balance Confidence Scale (ABC). PPV patients walked slower, with reduced cadence (all p < 0.01), stride length (p < 0.05), and increased double support (p < 0.01) compared to HS. These changes correlated with FES-I (R = -0.528, p < 0.001) and ABC (R = 0.481, p < 0.01). Walking deterioration under DTc did not differ between PPV patients and HS, but patients showed a reduced cognitive processing speed (p < 0.05). When walking with EC, gait speed decreased more in PPV patients compared to HS (p < 0.05). Patients with PPV show gait changes which correlate with their fear of falling and balance confidence. Absent visual feedback leads to more pronounced gait deteriorations in PPV patients than in HS, indicating a higher reliance of patients on visual information during walking. These findings support the view that the gait characteristics of PPV can be attributed to an inadequate, cautious gait control. PMID:24519356

  19. Transcranial Direct Current Stimulation (tDCS) of the visual cortex: a proof-of-concept study based on interictal electrophysiological abnormalities in migraine

    PubMed Central

    2013-01-01

    Background Preventive pharmacotherapy for migraine is not satisfactory because of the low efficacy/tolerability ratio of many available drugs. Novel and more efficient preventive strategies are therefore warranted. Abnormal excitability of cortical areas appears to play a pivotal role in migraine pathophysiology. Transcranial direct current stimulation (tDCS) is a non-invasive and safe technique that is able to durably modulate the activity of the underlying cerebral cortex, and is being tested in various medical indications. The results of small open studies using tDCS in migraine prophylaxis are conflicting, possibly because the optimal stimulation settings and the brain targets were not well chosen. We have previously shown that the cerebral cortex, especially the visual cortex, is hyperresponsive in migraine patients between attacks and provided evidence from evoked potential studies that this is due to a decreased cortical preactivation level. If one accepts this concept, anodal tDCS over the visual cortex may have therapeutic potentials in migraine prevention, as it is able to increase neuronal firing. Objective To study the effects of anodal tDCS on visual cortex activity in healthy volunteers (HV) and episodic migraine without aura patients (MoA), and its potentials for migraine prevention. Methods We recorded pattern-reversal visual evoked potentials (VEP) before and after a 15-min session of anodal tDCS over the visual cortex in 11 HV and 13 MoA interictally. Then 10 MoA patients reporting at least 4 attacks/month subsequently participated in a therapeutic study, and received 2 similar sessions of tDCS per week for 8 weeks as migraine preventive therapy. Results In HV as well as in MoA, anodal tDCS transiently increased habituation of the VEP N1P1 component. VEP amplitudes were not modified by tDCS. Preventive treatment with anodal tDCS turned out to be beneficial in MoA: migraine attack frequency, migraine days, attack duration and acute medication

  20. Oscillatory Sensory Selection Mechanisms during Intersensory Attention to Rhythmic Auditory and Visual Inputs: A Human Electro-Corticographic Investigation

    PubMed Central

    Gomez-Ramirez, Manuel; Kelly, Simon P.; Molholm, Sophie; Sehatpour, Pejman; Schwartz, Theodore H.; Foxe, John J.

    2012-01-01

    Oscillatory entrainment mechanisms are invoked during attentional processing of rhythmically occurring stimuli, whereby their phase-alignment regulates the excitability state of neurons coding for anticipated inputs. These mechanisms have been examined in the delta-band (1-3 Hz) where entrainment frequency matches the stimulation rate. Here, we investigated entrainment for sub-delta rhythmic stimulation, recording from intracranial electrodes over human auditory cortex during an intersensory audiovisual task. Audiovisual stimuli were presented at 0.67-Hz while participants detected targets within one sensory stream and ignored the other. It was found that entrainment operated at twice the stimulation rate (1.33Hz), and this was reflected by higher amplitude values in the FFT-spectrum, cyclic modulation of alpha-amplitude, and phase-amplitude coupling between delta-phase and alpha-power. In addition, we found that alpha-amplitude was relatively increased in auditory cortex coincident with to-be-ignored auditory stimuli during attention to vision. Thus, the data suggest that entrainment mechanisms operate within a delimited pass-band such that for sub-delta task rhythms, oscillatory harmonics are invoked. The phase of these delta-entrained oscillations modulates alpha-band power. This may in turn increase or decrease responsiveness to relevant and irrelevant stimuli, respectively. PMID:22171054

  1. Meiotic abnormalities

    SciTech Connect

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  2. Congenital Abnormalities

    MedlinePlus

    ... serious health problems (e.g. Down syndrome ). Single-Gene Abnormalities Sometimes the chromosomes are normal in number, ... blood flow to the fetus impair fetal growth. Alcohol consumption and certain drugs during pregnancy significantly increase ...

  3. Craniofacial Abnormalities

    MedlinePlus

    ... of the skull and face. Craniofacial abnormalities are birth defects of the face or head. Some, like cleft ... palate, are among the most common of all birth defects. Others are very rare. Most of them affect ...

  4. Walking abnormalities

    MedlinePlus

    ... include: Arthritis of the leg or foot joints Conversion disorder (a psychological disorder) Foot problems (such as a ... injuries. For an abnormal gait that occurs with conversion disorder, counseling and support from family members are strongly ...

  5. Chromosome Abnormalities

    MedlinePlus

    ... decade, newer techniques have been developed that allow scientists and doctors to screen for chromosomal abnormalities without using a microscope. These newer methods compare the patient's DNA to a normal DNA ...

  6. Nail abnormalities

    MedlinePlus

    Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails. ... Fungus or yeast cause changes in the color, texture, and shape of the nails. Bacterial infection may ...

  7. Differences in Visual-Spatial Input May Underlie Different Compression Properties of Firing Fields for Grid Cell Modules in Medial Entorhinal Cortex

    PubMed Central

    Raudies, Florian; Hasselmo, Michael E.

    2015-01-01

    Firing fields of grid cells in medial entorhinal cortex show compression or expansion after manipulations of the location of environmental barriers. This compression or expansion could be selective for individual grid cell modules with particular properties of spatial scaling. We present a model for differences in the response of modules to barrier location that arise from different mechanisms for the influence of visual features on the computation of location that drives grid cell firing patterns. These differences could arise from differences in the position of visual features within the visual field. When location was computed from the movement of visual features on the ground plane (optic flow) in the ventral visual field, this resulted in grid cell spatial firing that was not sensitive to barrier location in modules modeled with small spacing between grid cell firing fields. In contrast, when location was computed from static visual features on walls of barriers, i.e. in the more dorsal visual field, this resulted in grid cell spatial firing that compressed or expanded based on the barrier locations in modules modeled with large spacing between grid cell firing fields. This indicates that different grid cell modules might have differential properties for computing location based on visual cues, or the spatial radius of sensitivity to visual cues might differ between modules. PMID:26584432

  8. How cortical neurons help us see: visual recognition in the human brain.

    PubMed

    Blumberg, Julie; Kreiman, Gabriel

    2010-09-01

    Through a series of complex transformations, the pixel-like input to the retina is converted into rich visual perceptions that constitute an integral part of visual recognition. Multiple visual problems arise due to damage or developmental abnormalities in the cortex of the brain. Here, we provide an overview of how visual information is processed along the ventral visual cortex in the human brain. We discuss how neurophysiological recordings in macaque monkeys and in humans can help us understand the computations performed by visual cortex. PMID:20811161

  9. Parsing abnormal grain growth in specialty aluminas

    NASA Astrophysics Data System (ADS)

    Lawrence, Abigail Kremer

    Grain growth in alumina is strongly affected by the impurities present in the material. Certain impurity elements are known to have characteristic effects on abnormal grain growth in alumina. Specialty alumina powders contain multiple impurity species including MgO, CaO, SiO2, and Na 2O. In this work, sintered samples made from alumina powders containing various amounts of the impurities in question were characterized by their grain size and aspect ratio distributions. Multiple quantitative methods were used to characterize and classify samples with varying microstructures. The grain size distributions were used to partition the grain size population into subpopulations depending on the observed deviation from normal behavior. Using both grain size and aspect ratio a new visual representation for a microstructure was introduced called a morphology frequency map that gives a fingerprint for the material. The number of subpopulations within a sample and the shape of the distribution on the morphology map provided the basis for a classification scheme for different types of microstructures. Also using the two parameters a series of five metrics were calculated that describe the character of the abnormal grains in the sample, these were called abnormal character values. The abnormal character values describe the fraction of grains that are considered abnormal, the average magnitude of abnormality (including both grain size and aspect ratio), the average size, and variance in size. The final metric is the correlation between grain size and aspect ratio for the entire population of grains. The abnormal character values give a sense of how different from "normal" the sample is, given the assumption that a normal sample has a lognormal distribution of grain size and a Gaussian distribution of aspect ratios. In the second part of the work the quantified measures of abnormality were correlated with processing parameters such as composition and heat treatment conditions. A

  10. Coexpression of two visual pigments in a photoreceptor causes an abnormally broad spectral sensitivity in the eye of the butterfly Papilio xuthus.

    PubMed

    Arikawa, Kentaro; Mizuno, Shin; Kinoshita, Michiyo; Stavenga, Doekele G

    2003-06-01

    The compound eye of the butterfly Papilio xuthus consists of three different types of ommatidia, each containing nine photoreceptor cells (R1-R9). We have found previously that the R5-R8 photoreceptors of type II ommatidia coexpress two different mRNAs, encoding opsins of green- and orange-red-absorbing visual pigments (Kitamoto et al., 1998). Do these cells contain two functionally distinct visual pigments? First, we identified the sensitivity spectrum of these photoreceptors by using combined intracellular recording and dye injection. We thus found that the R5-R8 of type II ommatidia have a characteristic sensitivity spectrum extending over an excessively broad spectral range, from the violet to the red region; the photoreceptors are therefore termed broadband photoreceptors. The spectral shape was interpreted with a computational model for type II ommatidia, containing a UV visual pigment in cells R1 and R2, two green visual pigments in cells R3 and R4, a far-UV-absorbing screening pigment (3-hydroxyretinol) in the distal part of the ommatidium, and a red-screening pigment that surrounds the rhabdom. The modeling suggests that both visual pigments in the R5-R8 photoreceptors participate in phototransduction. This work provides the first compelling evidence that multiple visual pigments participate in phototransduction in single invertebrate photoreceptors. PMID:12805293

  11. What are the Effects of Severe Visual Impairment on the Cortical Organization and Connectivity of Primary Visual Cortex?

    PubMed Central

    Larsen, DeLaine D.; Luu, Julie D.; Burns, Marie E.; Krubitzer, Leah

    2009-01-01

    The organization and connections of the primary visual area (V1) were examined in mice that lacked functional rods (Gnat−/−), but had normal cone function. Because mice are nocturnal and rely almost exclusively on rod vision for normal behaviors, the Gnat−/− mice used in the present study are considered functionally blind. Our goal was to determine if visual cortex is reorganized in these mice, and to examine the neuroanatomical connections that may subserve reorganization. We found that most neurons in V1 responded to auditory, or some combination of auditory, somatosensory, and/or visual stimulation. We also determined that cortical connections of V1 in Gnat−/− mice were similar to those in normal animals, but even in normal animals, there is sparse input from auditory cortex (AC) to V1. An important observation was that most of the subcortical inputs to V1 were from thalamic nuclei that normally project to V1 such as the lateral geniculate (LG), lateral posterior (LP), and lateral dorsal (LD) nuclei. However, V1 also received some abnormal subcortical inputs from the anterior thalamic nuclei, the ventral posterior, the ventral lateral and the posterior nuclei. While the vision generated from the small number of cones appears to be sufficient to maintain most of the patterns of normal connectivity, the sparse abnormal thalamic inputs to VI, existing inputs from AC, and possibly abnormal inputs to LG and LP may be responsible for generating the alterations in the functional organization of V1. PMID:20057935

  12. Effects of Auditory Input in Individuation Tasks

    ERIC Educational Resources Information Center

    Robinson, Christopher W.; Sloutsky, Vladimir M.

    2008-01-01

    Under many conditions auditory input interferes with visual processing, especially early in development. These interference effects are often more pronounced when the auditory input is unfamiliar than when the auditory input is familiar (e.g. human speech, pre-familiarized sounds, etc.). The current study extends this research by examining how…

  13. Investigation of abnormal negative threshold voltage shift under positive bias stress in input/output n-channel metal-oxide-semiconductor field-effect transistors with TiN/HfO{sub 2} structure using fast I-V measurement

    SciTech Connect

    Ho, Szu-Han; Chen, Ching-En; Tseng, Tseung-Yuen; Chang, Ting-Chang Lu, Ying-Hsin; Tsai, Jyun-Yu; Liu, Kuan-Ju; Cheng, Osbert; Huang, Cheng-Tung; Lu, Ching-Sen

    2014-03-17

    This letter investigates abnormal negative threshold voltage shifts under positive bias stress in input/output (I/O) TiN/HfO{sub 2} n-channel metal-oxide-semiconductor field-effect transistors using fast I-V measurement. This phenomenon is attributed to a reversible charge/discharge effect in pre-existing bulk traps. Moreover, in standard performance devices, threshold-voltage (V{sub t}) shifts positively during fast I-V double sweep measurement. However, in I/O devices, V{sub t} shifts negatively since electrons escape from bulk traps to metal gate rather than channel electrons injecting to bulk traps. Consequently, decreasing pre-existing bulk traps in I/O devices, which can be achieved by adopting Hf{sub x}Zr{sub 1−x}O{sub 2} as gate oxide, can reduce the charge/discharge effect.

  14. Recognizing patterns of visual field loss using unsupervised machine learning

    NASA Astrophysics Data System (ADS)

    Yousefi, Siamak; Goldbaum, Michael H.; Zangwill, Linda M.; Medeiros, Felipe A.; Bowd, Christopher

    2014-03-01

    Glaucoma is a potentially blinding optic neuropathy that results in a decrease in visual sensitivity. Visual field abnormalities (decreased visual sensitivity on psychophysical tests) are the primary means of glaucoma diagnosis. One form of visual field testing is Frequency Doubling Technology (FDT) that tests sensitivity at 52 points within the visual field. Like other psychophysical tests used in clinical practice, FDT results yield specific patterns of defect indicative of the disease. We used Gaussian Mixture Model with Expectation Maximization (GEM), (EM is used to estimate the model parameters) to automatically separate FDT data into clusters of normal and abnormal eyes. Principal component analysis (PCA) was used to decompose each cluster into different axes (patterns). FDT measurements were obtained from 1,190 eyes with normal FDT results and 786 eyes with abnormal (i.e., glaucomatous) FDT results, recruited from a university-based, longitudinal, multi-center, clinical study on glaucoma. The GEM input was the 52-point FDT threshold sensitivities for all eyes. The optimal GEM model separated the FDT fields into 3 clusters. Cluster 1 contained 94% normal fields (94% specificity) and clusters 2 and 3 combined, contained 77% abnormal fields (77% sensitivity). For clusters 1, 2 and 3 the optimal number of PCA-identified axes were 2, 2 and 5, respectively. GEM with PCA successfully separated FDT fields from healthy and glaucoma eyes and identified familiar glaucomatous patterns of loss.

  15. Complex patterns of abnormal heartbeats

    NASA Technical Reports Server (NTRS)

    Schulte-Frohlinde, Verena; Ashkenazy, Yosef; Goldberger, Ary L.; Ivanov, Plamen Ch; Costa, Madalena; Morley-Davies, Adrian; Stanley, H. Eugene; Glass, Leon

    2002-01-01

    Individuals having frequent abnormal heartbeats interspersed with normal heartbeats may be at an increased risk of sudden cardiac death. However, mechanistic understanding of such cardiac arrhythmias is limited. We present a visual and qualitative method to display statistical properties of abnormal heartbeats. We introduce dynamical "heartprints" which reveal characteristic patterns in long clinical records encompassing approximately 10(5) heartbeats and may provide information about underlying mechanisms. We test if these dynamics can be reproduced by model simulations in which abnormal heartbeats are generated (i) randomly, (ii) at a fixed time interval following a preceding normal heartbeat, or (iii) by an independent oscillator that may or may not interact with the normal heartbeat. We compare the results of these three models and test their limitations to comprehensively simulate the statistical features of selected clinical records. This work introduces methods that can be used to test mathematical models of arrhythmogenesis and to develop a new understanding of underlying electrophysiologic mechanisms of cardiac arrhythmia.

  16. Retinal abnormalities in β-thalassemia major.

    PubMed

    Bhoiwala, Devang L; Dunaief, Joshua L

    2016-01-01

    Patients with beta (β)-thalassemia (β-TM: β-thalassemia major, β-TI: β-thalassemia intermedia) have a variety of complications that may affect all organs, including the eye. Ocular abnormalities include retinal pigment epithelial degeneration, angioid streaks, venous tortuosity, night blindness, visual field defects, decreased visual acuity, color vision abnormalities, and acute visual loss. Patients with β-thalassemia major are transfusion dependent and require iron chelation therapy to survive. Retinal degeneration may result from either retinal iron accumulation from transfusion-induced iron overload or retinal toxicity induced by iron chelation therapy. Some who were never treated with iron chelation therapy exhibited retinopathy, and others receiving iron chelation therapy had chelator-induced retinopathy. We will focus on retinal abnormalities present in individuals with β-thalassemia major viewed in light of new findings on the mechanisms and manifestations of retinal iron toxicity. PMID:26325202

  17. Abnormal Head Position

    MedlinePlus

    ... cause. Can a longstanding head turn lead to any permanent problems? Yes, a significant abnormal head posture could cause permanent ... occipitocervical synostosis and unilateral hearing loss. Are there any ... postures? Yes. Abnormal head postures can usually be improved depending ...

  18. Urine - abnormal color

    MedlinePlus

    ... straw-yellow. Abnormally colored urine may be cloudy, dark, or blood-colored. Causes Abnormal urine color may ... red blood cells, or mucus in the urine. Dark brown but clear urine is a sign of ...

  19. Visual processing in anorexia nervosa and body dysmorphic disorder: similarities, differences, and future research directions.

    PubMed

    Madsen, Sarah K; Bohon, Cara; Feusner, Jamie D

    2013-10-01

    Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are psychiatric disorders that involve distortion of the experience of one's physical appearance. In AN, individuals believe that they are overweight, perceive their body as "fat," and are preoccupied with maintaining a low body weight. In BDD, individuals are preoccupied with misperceived defects in physical appearance, most often of the face. Distorted visual perception may contribute to these cardinal symptoms, and may be a common underlying phenotype. This review surveys the current literature on visual processing in AN and BDD, addressing lower- to higher-order stages of visual information processing and perception. We focus on peer-reviewed studies of AN and BDD that address ophthalmologic abnormalities, basic neural processing of visual input, integration of visual input with other systems, neuropsychological tests of visual processing, and representations of whole percepts (such as images of faces, bodies, and other objects). The literature suggests a pattern in both groups of over-attention to detail, reduced processing of global features, and a tendency to focus on symptom-specific details in their own images (body parts in AN, facial features in BDD), with cognitive strategy at least partially mediating the abnormalities. Visuospatial abnormalities were also evident when viewing images of others and for non-appearance related stimuli. Unfortunately no study has directly compared AN and BDD, and most studies were not designed to disentangle disease-related emotional responses from lower-order visual processing. We make recommendations for future studies to improve the understanding of visual processing abnormalities in AN and BDD. PMID:23810196

  20. Visual processing in anorexia nervosa and body dysmorphic disorder: similarities, differences, and future research directions

    PubMed Central

    Madsen, Sarah K.; Bohon, Cara; Feusner, Jamie D.

    2013-01-01

    Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are psychiatric disorders that involve distortion of the experience of one’s physical appearance. In AN, individuals believe that they are overweight, perceive their body as “fat,” and are preoccupied with maintaining a low body weight. In BDD, individuals are preoccupied with misperceived defects in physical appearance, most often of the face. Distorted visual perception may contribute to these cardinal symptoms, and may be a common underlying phenotype. This review surveys the current literature on visual processing in AN and BDD, addressing lower- to higher-order stages of visual information processing and perception. We focus on peer-reviewed studies of AN and BDD that address ophthalmologic abnormalities, basic neural processing of visual input, integration of visual input with other systems, neuropsychological tests of visual processing, and representations of whole percepts (such as images of faces, bodies, and other objects). The literature suggests a pattern in both groups of over-attention to detail, reduced processing of global features, and a tendency to focus on symptom-specific details in their own images (body parts in AN, facial features in BDD), with cognitive strategy at least partially mediating the abnormalities. Visuospatial abnormalities were also evident when viewing images of others and for non-appearance related stimuli. Unfortunately no study has directly compared AN and BDD, and most studies were not designed to disentangle disease-related emotional responses from lower-order visual processing. We make recommendations for future studies to improve the understanding of visual processing abnormalities in AN and BDD. PMID:23810196

  1. Visual cognition

    PubMed Central

    Cavanagh, Patrick

    2011-01-01

    Visual cognition, high-level vision, mid-level vision and top-down processing all refer to decision-based scene analyses that combine prior knowledge with retinal input to generate representations. The label “visual cognition” is little used at present, but research and experiments on mid- and high-level, inference-based vision have flourished, becoming in the 21st century a significant, if often understated part, of current vision research. How does visual cognition work? What are its moving parts? This paper reviews the origins and architecture of visual cognition and briefly describes some work in the areas of routines, attention, surfaces, objects, and events (motion, causality, and agency). Most vision scientists avoid being too explicit when presenting concepts about visual cognition, having learned that explicit models invite easy criticism. What we see in the literature is ample evidence for visual cognition, but few or only cautious attempts to detail how it might work. This is the great unfinished business of vision research: at some point we will be done with characterizing how the visual system measures the world and we will have to return to the question of how vision constructs models of objects, surfaces, scenes, and events. PMID:21329719

  2. Abnormal Saccadic Eye Movements in Autistic Children.

    ERIC Educational Resources Information Center

    Kemner, C.; Verbaten, M. N.; Cuperus, J. M.; Camfferman, G.; van Engeland, H.

    1998-01-01

    The saccadic eye movements, generated during a visual oddball task, were compared for 10 autistic children, 10 children with attention deficit hyperactivity disorder, 10 dyslexic children, and 10 typically developing children. Several abnormal patterns of saccades were found in the autistic group. (DB)

  3. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  4. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... from many different conditions. Specific diseases can affect tooth shape, tooth color, time of appearance, or absence ...

  5. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  6. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    PubMed

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    whose frequency correlated significantly with generalized reductions in cortical thickness. Patients with both posterior cortical atrophy and typical Alzheimer's disease showed lower gain in smooth pursuit compared to controls. The current study establishes that eye movement abnormalities are near-ubiquitous in posterior cortical atrophy, and highlights multiple aspects of saccadic performance which distinguish posterior cortical atrophy from typical Alzheimer's disease. We suggest the posterior cortical atrophy oculomotor profile (e.g. exacerbation of the saccadic gap/overlap effect, preserved saccadic velocity) reflects weak input from degraded occipito-parietal spatial representations of stimulus location into a superior collicular spatial map for eye movement regulation. This may indicate greater impairment of identification of oculomotor targets rather than generation of oculomotor movements. The results highlight the critical role of spatial attention and object identification but also precise stimulus localization in explaining the complex real world perception deficits observed in posterior cortical atrophy and many other patients with dementia-related visual impairment. PMID:25895507

  7. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy

    PubMed Central

    Kaski, Diego; Yong, Keir X. X.; Paterson, Ross W.; Slattery, Catherine F.; Ryan, Natalie S.; Schott, Jonathan M.; Crutch, Sebastian J.

    2015-01-01

    saccadic intrusions whose frequency correlated significantly with generalized reductions in cortical thickness. Patients with both posterior cortical atrophy and typical Alzheimer’s disease showed lower gain in smooth pursuit compared to controls. The current study establishes that eye movement abnormalities are near-ubiquitous in posterior cortical atrophy, and highlights multiple aspects of saccadic performance which distinguish posterior cortical atrophy from typical Alzheimer’s disease. We suggest the posterior cortical atrophy oculomotor profile (e.g. exacerbation of the saccadic gap/overlap effect, preserved saccadic velocity) reflects weak input from degraded occipito-parietal spatial representations of stimulus location into a superior collicular spatial map for eye movement regulation. This may indicate greater impairment of identification of oculomotor targets rather than generation of oculomotor movements. The results highlight the critical role of spatial attention and object identification but also precise stimulus localization in explaining the complex real world perception deficits observed in posterior cortical atrophy and many other patients with dementia-related visual impairment. PMID:25895507

  8. "Jeopardy" in Abnormal Psychology.

    ERIC Educational Resources Information Center

    Keutzer, Carolin S.

    1993-01-01

    Describes the use of the board game, Jeopardy, in a college level abnormal psychology course. Finds increased student interaction and improved application of information. Reports generally favorable student evaluation of the technique. (CFR)

  9. Abnormal Uterine Bleeding

    MedlinePlus

    ... Abnormal uterine bleeding is any bleeding from the uterus (through your vagina) other than your normal monthly ... or fibroids (small and large growths) in the uterus can also cause bleeding. Rarely, a thyroid problem, ...

  10. Abnormal Uterine Bleeding FAQ

    MedlinePlus

    ... as cancer of the uterus, cervix, or vagina • Polycystic ovary syndrome How is abnormal bleeding diagnosed? Your health care ... before the fetus can survive outside the uterus. Polycystic Ovary Syndrome: A condition characterized by two of the following ...

  11. Spectrum of visual disorders in children with cerebral visual impairment.

    PubMed

    Fazzi, Elisa; Signorini, Sabrina Giovanna; Bova, Stefania Maria; La Piana, Roberta; Ondei, Paola; Bertone, Chiara; Misefari, Walter; Bianchi, Paolo Emilio

    2007-03-01

    Cerebral visual impairment is a visual function deficit caused by damage to the retrogeniculate visual pathways in the absence of any major ocular disease. It is the main visual deficit in children in the developed world. Preperinatal hypoxic-ischemic damage is the most frequent cause of cerebral visual impairment, but the etiology is variable. The authors set out to evaluate the presence of visual disorders not attributable to any major ocular pathology in a sample of children with central nervous system disease and to describe the clinical picture of cerebral visual impairment in this cohort. One hundred twenty-one patients with central nervous system damage and visual impairment underwent a protocol developed at the authors' center that included neurologic, neurophthalmologic, and neuroradiologic assessments (brain magnetic resonance imaging). Reduced visual acuity was found in 105 of 121 patients, reduced contrast sensitivity in 58, abnormal optokinetic nystagmus in 88, and visual field deficit in 7. Fixation was altered in 58 patients, smooth pursuit in 95, and saccadic movements in 41. Strabismus was present in 88 patients, and abnormal ocular movements were found in 43 patients. Of the 27 patients in whom they could be assessed, visual-perceptual abilities were found to be impaired in 24. Fundus oculi abnormalities and refractive errors were frequently associated findings. This study confirms that the clinical expression of cerebral visual impairment can be variable and that, in addition to already well-documented symptoms (such as reduced visual acuity, visual field deficits, reduced contrast sensitivity), the clinical picture can also be characterized by oculomotor or visual-cognitive disorders. Cerebral visual impairment is often associated with ophthalmologic abnormalities, and these should be carefully sought. Early and careful assessment, taking into account both the neurophthalmologic and the ophthalmologic aspects, is essential for a correct

  12. Chromosomal Abnormalities and Schizophrenia

    PubMed Central

    BASSETT, ANNE S.; CHOW, EVA W.C.; WEKSBERG, ROSANNA

    2011-01-01

    Schizophrenia is a common and serious psychiatric illness with strong evidence for genetic causation, but no specific loci yet identified. Chromosomal abnormalities associated with schizophrenia may help to understand the genetic complexity of the illness. This paper reviews the evidence for associations between chromosomal abnormalities and schizophrenia and related disorders. The results indicate that 22q11.2 microdeletions detected by fluorescence in-situ hybridization (FISH) are significantly associated with schizophrenia. Sex chromosome abnormalities seem to be increased in schizophrenia but insufficient data are available to indicate whether schizophrenia or related disorders are increased in patients with sex chromosome aneuploidies. Other reports of chromosomal abnormalities associated with schizophrenia have the potential to be important adjuncts to linkage studies in gene localization. Advances in molecular cytogenetic techniques (i.e., FISH) have produced significant increases in rates of identified abnormalities in schizophrenia, particularly in patients with very early age at onset, learning difficulties or mental retardation, or dysmorphic features. The results emphasize the importance of considering behavioral phenotypes, including adult onset psychiatric illnesses, in genetic syndromes and the need for clinicians to actively consider identifying chromosomal abnormalities and genetic syndromes in selected psychiatric patients. PMID:10813803

  13. Sound can suppress visual perception.

    PubMed

    Hidaka, Souta; Ide, Masakazu

    2015-01-01

    In a single modality, the percept of an input (e.g., voices of neighbors) is often suppressed by another (e.g., the sound of a car horn nearby) due to close interactions of neural responses to these inputs. Recent studies have also suggested that close interactions of neural responses could occur even across sensory modalities, especially for audio-visual interactions. However, direct behavioral evidence regarding the audio-visual perceptual suppression effect has not been reported in a study with humans. Here, we investigated whether sound could have a suppressive effect on visual perception. We found that white noise bursts presented through headphones degraded visual orientation discrimination performance. This auditory suppression effect on visual perception frequently occurred when these inputs were presented in a spatially and temporally consistent manner. These results indicate that the perceptual suppression effect could occur across auditory and visual modalities based on close and direct neural interactions among those sensory inputs. PMID:26023877

  14. Talking Speech Input.

    ERIC Educational Resources Information Center

    Berliss-Vincent, Jane; Whitford, Gigi

    2002-01-01

    This article presents both the factors involved in successful speech input use and the potential barriers that may suggest that other access technologies could be more appropriate for a given individual. Speech input options that are available are reviewed and strategies for optimizing use of speech recognition technology are discussed. (Contains…

  15. MDS MIC Catalog Inputs

    NASA Technical Reports Server (NTRS)

    Johnson-Throop, Kathy A.; Vowell, C. W.; Smith, Byron; Darcy, Jeannette

    2006-01-01

    This viewgraph presentation reviews the inputs to the MDS Medical Information Communique (MIC) catalog. The purpose of the group is to provide input for updating the MDS MIC Catalog and to request that MMOP assign Action Item to other working groups and FSs to support the MITWG Process for developing MIC-DDs.

  16. High input impedance amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard L.

    1995-01-01

    High input impedance amplifiers are provided which reduce the input impedance solely to a capacitive reactance, or, in a somewhat more complex design, provide an extremely high essentially infinite, capacitive reactance. In one embodiment, where the input impedance is reduced in essence, to solely a capacitive reactance, an operational amplifier in a follower configuration is driven at its non-inverting input and a resistor with a predetermined magnitude is connected between the inverting and non-inverting inputs. A second embodiment eliminates the capacitance from the input by adding a second stage to the first embodiment. The second stage is a second operational amplifier in a non-inverting gain-stage configuration where the output of the first follower stage drives the non-inverting input of the second stage and the output of the second stage is fed back to the non-inverting input of the first stage through a capacitor of a predetermined magnitude. These amplifiers, while generally useful, are very useful as sensor buffer amplifiers that may eliminate significant sources of error.

  17. Format( )MEDIC( )Input

    NASA Astrophysics Data System (ADS)

    Foster, K.

    1994-09-01

    This document is a description of a computer program called Format( )MEDIC( )Input. The purpose of this program is to allow the user to quickly reformat wind velocity data in the Model Evaluation Database (MEDb) into a reasonable 'first cut' set of MEDIC input files (MEDIC.nml, StnLoc.Met, and Observ.Met). The user is cautioned that these resulting input files must be reviewed for correctness and completeness. This program will not format MEDb data into a Problem Station Library or Problem Metdata File. A description of how the program reformats the data is provided, along with a description of the required and optional user input and a description of the resulting output files. A description of the MEDb is not provided here but can be found in the RAS Division Model Evaluation Database Description document.

  18. Morphological abnormalities in elasmobranchs.

    PubMed

    Moore, A B M

    2015-08-01

    A total of 10 abnormal free-swimming (i.e., post-birth) elasmobranchs are reported from The (Persian-Arabian) Gulf, encompassing five species and including deformed heads, snouts, caudal fins and claspers. The complete absence of pelvic fins in a milk shark Rhizoprionodon acutus may be the first record in any elasmobranch. Possible causes, including the extreme environmental conditions and the high level of anthropogenic pollution particular to The Gulf, are briefly discussed. PMID:25903257

  19. Chromosome abnormalities in glioma

    SciTech Connect

    Li, Y.S.; Ramsay, D.A.; Fan, Y.S.

    1994-09-01

    Cytogenetic studies were performed in 25 patients with gliomas. An interesting finding was a seemingly identical abnormality, an extra band on the tip of the short arm of chromosome 1, add(1)(p36), in two cases. The abnormality was present in all cells from a patient with a glioblastoma and in 27% of the tumor cells from a patient with a recurrent irradiated anaplastic astrocytoma; in the latter case, 7 unrelated abnormal clones were identified except 4 of those clones shared a common change, -Y. Three similar cases have been described previously. In a patient with pleomorphic astrocytoma, the band 1q42 in both homologues of chromosome 1 was involved in two different rearrangements. A review of the literature revealed that deletion of the long arm of chromosome 1 including 1q42 often occurs in glioma. This may indicate a possible tumor suppressor gene in this region. Cytogenetic follow-up studies were carried out in two patients and emergence of unrelated clones were noted in both. A total of 124 clonal breakpoints were identified in the 25 patients. The breakpoints which occurred three times or more were: 1p36, 1p22, 1q21, 1q25, 3q21, 7q32, 8q22, 9q22, 16q22, and 22q13.

  20. [Congenital foot abnormalities].

    PubMed

    Delpont, M; Lafosse, T; Bachy, M; Mary, P; Alves, A; Vialle, R

    2015-03-01

    The foot may be the site of birth defects. These abnormalities are sometimes suspected prenatally. Final diagnosis depends on clinical examination at birth. These deformations can be simple malpositions: metatarsus adductus, talipes calcaneovalgus and pes supinatus. The prognosis is excellent spontaneously or with a simple orthopedic treatment. Surgery remains outstanding. The use of a pediatric orthopedist will be considered if malposition does not relax after several weeks. Malformations (clubfoot, vertical talus and skew foot) require specialized care early. Clubfoot is characterized by an equine and varus hindfoot, an adducted and supine forefoot, not reducible. Vertical talus combines equine hindfoot and dorsiflexion of the forefoot, which is performed in the midfoot instead of the ankle. Skew foot is suspected when a metatarsus adductus is resistant to conservative treatment. Early treatment is primarily orthopedic at birth. Surgical treatment begins to be considered after walking age. Keep in mind that an abnormality of the foot may be associated with other conditions: malposition with congenital hip, malformations with syndromes, neurological and genetic abnormalities. PMID:25524290

  1. Electroencephalographic Abnormalities in Clozapine-Treated Patients: A Cross-Sectional Study

    PubMed Central

    Goyal, Nishant; Desarkar, Pushpal; Nizamie, Haque

    2011-01-01

    The objective of our study was to examine the electroencephalogram (EEG) abnormalities associated with clozapine treatment. It was a cross-sectional study on 87 psychiatric patients on clozapine treatment. 32 channel digital EEG was recorded and analysed visually for abnormalities. EEG abnormalities were observed in 63.2% of patients. Both slowing and epileptiform activities were noted in 41.4% of patients. The EEG abnormalities were not associated with dose or duration of clozapine exposure. PMID:22216049

  2. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

    So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

  3. Feeling Abnormal: Simulation of Deviancy in Abnormal and Exceptionality Courses.

    ERIC Educational Resources Information Center

    Fernald, Charles D.

    1980-01-01

    Describes activity in which student in abnormal psychology and psychology of exceptional children classes personally experience being judged abnormal. The experience allows the students to remember relevant research, become sensitized to the feelings of individuals classified as deviant, and use caution in classifying individuals as abnormal.…

  4. Modeling Recognition Memory Using the Similarity Structure of Natural Input

    ERIC Educational Resources Information Center

    Lacroix, Joyca P. W.; Murre, Jaap M. J.; Postma, Eric O.; van den Herik, H. Jaap

    2006-01-01

    The natural input memory (NAM) model is a new model for recognition memory that operates on natural visual input. A biologically informed perceptual preprocessing method takes local samples (eye fixations) from a natural image and translates these into a feature-vector representation. During recognition, the model compares incoming preprocessed…

  5. Input Decimated Ensembles

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Oza, Nikunj C.; Clancy, Daniel (Technical Monitor)

    2001-01-01

    Using an ensemble of classifiers instead of a single classifier has been shown to improve generalization performance in many pattern recognition problems. However, the extent of such improvement depends greatly on the amount of correlation among the errors of the base classifiers. Therefore, reducing those correlations while keeping the classifiers' performance levels high is an important area of research. In this article, we explore input decimation (ID), a method which selects feature subsets for their ability to discriminate among the classes and uses them to decouple the base classifiers. We provide a summary of the theoretical benefits of correlation reduction, along with results of our method on two underwater sonar data sets, three benchmarks from the Probenl/UCI repositories, and two synthetic data sets. The results indicate that input decimated ensembles (IDEs) outperform ensembles whose base classifiers use all the input features; randomly selected subsets of features; and features created using principal components analysis, on a wide range of domains.

  6. Abnormal human sex chromosome constitutions

    SciTech Connect

    1993-12-31

    Chapter 22, discusses abnormal human sex chromosome constitution. Aneuploidy of X chromosomes with a female phenotype, sex chromosome aneuploidy with a male phenotype, and various abnormalities in X chromosome behavior are described. 31 refs., 2 figs.

  7. Exercises to Improve Gait Abnormalities

    MedlinePlus

    ... Home About iChip Articles Directories Videos Resources Contact Exercises to Improve Gait Abnormalities Home » Article Categories » Exercise and Fitness Font Size: A A A A Exercises to Improve Gait Abnormalities Next Page The manner ...

  8. Spirometric abnormalities among welders

    SciTech Connect

    Rastogi, S.K.; Gupta, B.N.; Husain, T.; Mathur, N.; Srivastava, S. )

    1991-10-01

    A group of manual welders age group 13-60 years having a mean exposure period of 12.4 {plus minus} 1.12 years were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The welders showed a significantly higher prevalence of respiratory impairment than that observed among the unexposed controls as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the expose group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment followed by a mixed ventilatory defect among the welders. The effect of age on pulmonary impairment was not discernible. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years. Smoking also had a contributory role.

  9. Visual field

    MedlinePlus

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam : This is a quick and basic check of the visual field. The health care provider ...

  10. Visual Learning.

    ERIC Educational Resources Information Center

    Kirrane, Diane E.

    1992-01-01

    An increasingly visual culture is affecting work and training. Achievement of visual literacy means acquiring competence in critical analysis of visual images and in communicating through visual media. (SK)

  11. Visual field

    MedlinePlus

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam : This is a quick and basic check of the visual field. The health care provider sits directly in front ...

  12. Visual disorders in children with brain lesions: 2. Visual impairment associated with cerebral palsy.

    PubMed

    Guzzetta, A; Mercuri, E; Cioni, G

    2001-01-01

    Disorders of visual function are a common finding in children with cerebral palsy. In some cases they are secondary to ophthalmologic abnormalities such as cataract or retinopathy, but more often they are due to damage of the central visual pathway. We review the literature on the prevalence and distribution of visual abnormalities in children with cerebral palsy and their relation to cognitive, motor and emotional development. PMID:11589165

  13. Serial dependence in visual perception

    PubMed Central

    Fischer, Jason; Whitney, David

    2014-01-01

    Visual input often arrives in a noisy and discontinuous stream, owing to head and eye movements, occlusion, lighting changes, and many other factors. Yet the physical world is generally stable—objects and physical characteristics rarely change spontaneously. How then does the human visual system capitalize on continuity in the physical environment over time? Here we show that visual perception is serially dependent, using both prior and present input to inform perception at the present moment. Using an orientation judgment task, we found that even when visual input changes randomly over time, perceived orientation is strongly and systematically biased toward recently seen stimuli. Further, the strength of this bias is modulated by attention and tuned to the spatial and temporal proximity of successive stimuli. These results reveal a serial dependence in perception characterized by a spatiotemporally tuned, orientation-selective operator—which we call a continuity field—that may promote visual stability over time. PMID:24686785

  14. Eye movement abnormalities.

    PubMed

    Moncayo, Jorge; Bogousslavsky, Julien

    2012-01-01

    Generation and control of eye movements requires the participation of the cortex, basal ganglia, cerebellum and brainstem. The signals of this complex neural network finally converge on the ocular motoneurons of the brainstem. Infarct or hemorrhage at any level of the oculomotor system (though more frequent in the brain-stem) may give rise to a broad spectrum of eye movement abnormalities (EMAs). Consequently, neurologists and particularly stroke neurologists are routinely confronted with EMAs, some of which may be overlooked in the acute stroke setting and others that, when recognized, may have a high localizing value. The most complex EMAs are due to midbrain stroke. Horizontal gaze disorders, some of them manifesting unusual patterns, may occur in pontine stroke. Distinct varieties of nystagmus occur in cerebellar and medullary stroke. This review summarizes the most representative EMAs from the supratentorial level to the brainstem. PMID:22377853

  15. Abnormal Fixational Eye Movements in Amblyopia

    PubMed Central

    Shaikh, Aasef G.; Otero-Millan, Jorge; Kumar, Priyanka; Ghasia, Fatema F.

    2016-01-01

    Purpose Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood. Methods Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls. Results We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift. Discussion This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity. PMID:26930079

  16. When audiovisual correspondence disturbs visual processing.

    PubMed

    Hong, Sang Wook; Shim, Won Mok

    2016-05-01

    Multisensory integration is known to create a more robust and reliable perceptual representation of one's environment. Specifically, a congruent auditory input can make a visual stimulus more salient, consequently enhancing the visibility and detection of the visual target. However, it remains largely unknown whether a congruent auditory input can also impair visual processing. In the current study, we demonstrate that temporally congruent auditory input disrupts visual processing, consequently slowing down visual target detection. More importantly, this cross-modal inhibition occurs only when the contrast of visual targets is high. When the contrast of visual targets is low, enhancement of visual target detection is observed, consistent with the prediction based on the principle of inverse effectiveness (PIE) in cross-modal integration. The switch of the behavioral effect of audiovisual interaction from benefit to cost further extends the PIE to encompass the suppressive cross-modal interaction. PMID:26884130

  17. Hypermnesia using auditory input.

    PubMed

    Allen, J

    1992-07-01

    The author investigated whether hypermnesia would occur with auditory input. In addition, the author examined the effects of subjects' knowledge that they would later be asked to recall the stimuli. Two groups of 26 subjects each were given three successive recall trials after they listened to an audiotape of 59 high-imagery nouns. The subjects in the uninformed group were not told that they would later be asked to remember the words; those in the informed group were. Hypermnesia was evident, but only in the uninformed group. PMID:1447564

  18. Input distributions for VISA

    SciTech Connect

    Liebetrau, A.M.

    1983-10-01

    Work is underway at Pacific Northwest Laboratory (PNL) to improve the probabilistic analysis used to model pressurized thermal shock (PTS) incidents in reactor pressure vessels, and, further, to incorporate these improvements into the existing Vessel Integrity Simulation Analysis (VISA) code. Two topics related to work on input distributions in VISA are discussed in this paper. The first involves the treatment of flaw size distributions and the second concerns errors in the parameters in the (Guthrie) equation which is used to compute ..delta..RT/sub NDT/, the shift in reference temperature for nil ductility transition.

  19. Neurophysiological model of the normal and abnormal human pupil

    NASA Technical Reports Server (NTRS)

    Krenz, W.; Robin, M.; Barez, S.; Stark, L.

    1985-01-01

    Anatomical, experimental, and computer simulation studies were used to determine the structure of the neurophysiological model of the pupil size control system. The computer simulation of this model demonstrates the role played by each of the elements in the neurological pathways influencing the size of the pupil. Simulations of the effect of drugs and common abnormalities in the system help to illustrate the workings of the pathways and processes involved. The simulation program allows the user to select pupil condition (normal or an abnormality), specific site along the neurological pathway (retina, hypothalamus, etc.) drug class input (barbiturate, narcotic, etc.), stimulus/response mode, display mode, stimulus type and input waveform, stimulus or background intensity and frequency, the input and output conditions, and the response at the neuroanatomical site. The model can be used as a teaching aid or as a tool for testing hypotheses regarding the system.

  20. Ictal Cardiac Ryhthym Abnormalities

    PubMed Central

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic–clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  1. Abnormal uterine bleeding.

    PubMed

    Whitaker, Lucy; Critchley, Hilary O D

    2016-07-01

    Abnormal uterine bleeding (AUB) is a common and debilitating condition with high direct and indirect costs. AUB frequently co-exists with fibroids, but the relationship between the two remains incompletely understood and in many women the identification of fibroids may be incidental to a menstrual bleeding complaint. A structured approach for establishing the cause using the Fédération International de Gynécologie et d'Obstétrique (FIGO) PALM-COEIN (Polyp, Adenomyosis, Leiomyoma, Malignancy (and hyperplasia), Coagulopathy, Ovulatory disorders, Endometrial, Iatrogenic and Not otherwise classified) classification system will facilitate accurate diagnosis and inform treatment options. Office hysteroscopy and increasing sophisticated imaging will assist provision of robust evidence for the underlying cause. Increased availability of medical options has expanded the choice for women and many will no longer need to recourse to potentially complicated surgery. Treatment must remain individualised and encompass the impact of pressure symptoms, desire for retention of fertility and contraceptive needs, as well as address the management of AUB in order to achieve improved quality of life. PMID:26803558

  2. A model of visual perception.

    PubMed

    Borello, L; Ferraro, M; Penengo, P; Rossotti, M L

    1981-01-01

    In this paper we propose a model of visual perception in which a positive feedback mechanism can reproduce the pattern stimulus on a neurons screen. The pattern stimulus reproduction is based on informations coming from the spatial derivatives of visual pattern. This information together with the response of the feature extractors provides to the reproduction of the visual pattern as neuron screen electric activity. We simulate several input patterns and prove that the model reproduces the percept. PMID:7236747

  3. Electrocardiograph abnormalities revealed during laparoscopy

    PubMed Central

    Nijjer, Sukhjinder; Dubrey, Simon William

    2010-01-01

    This brief case presents a well patient in whom an electrocardiograph abnormality consistent with an accessory pathway was found during a routine procedure. We present the electrocardiographs, explain the underlying condition, and consider why the abnormality was revealed in this manner. PMID:22419949

  4. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  5. Haem degradation in abnormal haemoglobins.

    PubMed Central

    Brown, S B; Docherty, J C

    1978-01-01

    The coupled oxidation of certain abnormal haemoglobins leads to different bile-pigment isomer distributions from that of normal haemoglobin. The isomer pattern may be correlated with the structure of the abnormal haemoglobin in the neighbourhood of the haem pocket. This is support for haem degradation by an intramolecular reaction. PMID:708385

  6. Arctic science input wanted

    NASA Astrophysics Data System (ADS)

    The Arctic Research and Policy Act (Eos, June 26, 1984, p. 412) was signed into law by President Ronald Reagan this past July. One of its objectives is to develop a 5-year research plan for the Arctic. A request for input to this plan is being issued this week to nearly 500 people in science, engineering, and industry.To promote Arctic research and to recommend research policy in the Arctic, the new law establishes a five-member Arctic Research Commission, to be appointed by the President, and establishes an Interagency Arctic Research Policy Committee, to be composed of representatives from nearly a dozen agencies having interests in the region. The commission will make policy recommendations, and the interagency committee will implement those recommendations. The National Science Foundation (NSF) has been designated as the lead agency of the interagency committee.

  7. Which visual functions depend on intermediate visual regions? Insights from a case of developmental visual form agnosia.

    PubMed

    Gilaie-Dotan, Sharon

    2016-03-01

    A key question in visual neuroscience is the causal link between specific brain areas and perceptual functions; which regions are necessary for which visual functions? While the contribution of primary visual cortex and high-level visual regions to visual perception has been extensively investigated, the contribution of intermediate visual areas (e.g. V2/V3) to visual processes remains unclear. Here I review more than 20 visual functions (early, mid, and high-level) of LG, a developmental visual agnosic and prosopagnosic young adult, whose intermediate visual regions function in a significantly abnormal fashion as revealed through extensive fMRI and ERP investigations. While expectedly, some of LG's visual functions are significantly impaired, some of his visual functions are surprisingly normal (e.g. stereopsis, color, reading, biological motion). During the period of eight-year testing described here, LG trained on a perceptual learning paradigm that was successful in improving some but not all of his visual functions. Following LG's visual performance and taking into account additional findings in the field, I propose a framework for how different visual areas contribute to different visual functions, with an emphasis on intermediate visual regions. Thus, although rewiring and plasticity in the brain can occur during development to overcome and compensate for hindering developmental factors, LG's case seems to indicate that some visual functions are much less dependent on strict hierarchical flow than others, and can develop normally in spite of abnormal mid-level visual areas, thereby probably less dependent on intermediate visual regions. PMID:26209358

  8. Electroencephalographic abnormalities in antisocial personality disorder.

    PubMed

    Calzada-Reyes, Ana; Alvarez-Amador, Alfredo; Galán-García, Lídice; Valdés-Sosa, Mitchell

    2012-01-01

    The presence of brain dysfunction in violent offenders has been frequently examined with inconsistent results. The aim of the study was to assess the EEG of 84 violent offenders by visual inspection and frequency-domain quantitative analysis in 84 violent prisoners. Low-resolution electromagnetic tomography (LORETA) was also employed for theta band of the EEG spectra. Antisocial personality disorder (ASPD) was present in 50 of the offenders and it was absent in the remaining 34. The prevalence of EEG abnormalities, by visual inspection, was similar for both the ASPD group (82%) and non-ASPD group (79%). The brain topography of these anomalies also did not differ between groups, in contrast to results of the EEG quantitative analysis (QEEG) and LORETA that showed remarkable regional differences between both groups. QEEG analysis showed a pattern of excess of theta-delta activities and decrease of alpha band on the right fronto-temporal and left temporo-parietal regions in the ASPD group. LORETA signified an increase of theta activity (5.08 Hz) in ASPD group relative to non-ASPD group within left temporal and parietal regions. Findings indicate that QEEG analysis and techniques of source localization may reveal differences in brain electrical activity among offenders with ASPD, which was not obvious to visual inspection. PMID:22152445

  9. Computer Access for the Visually Impaired.

    ERIC Educational Resources Information Center

    Krolick, Bettye

    1984-01-01

    Provides information on and evaluation of microcomputer equipment modifications for improving accessibility to the visually impaired. Equipment discussed includes input and visual output modification techniques and devices, software designed for visually impaired users, and braille output peripherals. Lists sources for available peripherals,…

  10. Input Multiplicities in Process Control.

    ERIC Educational Resources Information Center

    Koppel, Lowell B.

    1983-01-01

    Describes research investigating potential effect of input multiplicity on multivariable chemical process control systems. Several simple processes are shown to exhibit the possibility of theoretical developments on input multiplicity and closely related phenomena are discussed. (JN)

  11. Modeling and generating input processes

    SciTech Connect

    Johnson, M.E.

    1987-01-01

    This tutorial paper provides information relevant to the selection and generation of stochastic inputs to simulation studies. The primary area considered is multivariate but much of the philosophy at least is relevant to univariate inputs as well. 14 refs.

  12. Chromosomal abnormalities in human sperm

    SciTech Connect

    Martin, R.H.

    1985-01-01

    The ability to analyze human sperm chromosome complements after penetration of zona pellucida-free hamster eggs provides the first opportunity to study the frequency and type of chromosomal abnormalities in human gametes. Two large-scale studies have provided information on normal men. We have studied 1,426 sperm complements from 45 normal men and found an abnormality rate of 8.9%. Brandriff et al. (5) found 8.1% abnormal complements in 909 sperm from 4 men. The distribution of numerical and structural abnormalities was markedly dissimilar in the 2 studies. The frequency of aneuploidy was 5% in our sample and only 1.6% in Brandriff's, perhaps reflecting individual variability among donors. The frequency of 24,YY sperm was low: 0/1,426 and 1/909. This suggests that the estimates of nondisjunction based on fluorescent Y body data (1% to 5%) are not accurate. We have also studied men at increased risk of sperm chromosomal abnormalities. The frequency of chromosomally unbalanced sperm in 6 men heterozygous for structural abnormalities varied dramatically: 77% for t11;22, 32% for t6;14, 19% for t5;18, 13% for t14;21, and 0% for inv 3 and 7. We have also studied 13 cancer patients before and after radiotherapy and demonstrated a significant dose-dependent increase of sperm chromosome abnormalities (numerical and structural) 36 months after radiation treatment.

  13. Haematological abnormalities in mitochondrial disorders

    PubMed Central

    Finsterer, Josef; Frank, Marlies

    2015-01-01

    INTRODUCTION This study aimed to assess the kind of haematological abnormalities that are present in patients with mitochondrial disorders (MIDs) and the frequency of their occurrence. METHODS The blood cell counts of a cohort of patients with syndromic and non-syndromic MIDs were retrospectively reviewed. MIDs were classified as ‘definite’, ‘probable’ or ‘possible’ according to clinical presentation, instrumental findings, immunohistological findings on muscle biopsy, biochemical abnormalities of the respiratory chain and/or the results of genetic studies. Patients who had medical conditions other than MID that account for the haematological abnormalities were excluded. RESULTS A total of 46 patients (‘definite’ = 5; ‘probable’ = 9; ‘possible’ = 32) had haematological abnormalities attributable to MIDs. The most frequent haematological abnormality in patients with MIDs was anaemia. 27 patients had anaemia as their sole haematological problem. Anaemia was associated with thrombopenia (n = 4), thrombocytosis (n = 2), leucopenia (n = 2), and eosinophilia (n = 1). Anaemia was hypochromic and normocytic in 27 patients, hypochromic and microcytic in six patients, hyperchromic and macrocytic in two patients, and normochromic and microcytic in one patient. Among the 46 patients with a mitochondrial haematological abnormality, 78.3% had anaemia, 13.0% had thrombopenia, 8.7% had leucopenia and 8.7% had eosinophilia, alone or in combination with other haematological abnormalities. CONCLUSION MID should be considered if a patient’s abnormal blood cell counts (particularly those associated with anaemia, thrombopenia, leucopenia or eosinophilia) cannot be explained by established causes. Abnormal blood cell counts may be the sole manifestation of MID or a collateral feature of a multisystem problem. PMID:26243978

  14. An anatomical basis for visual calibration of the auditory space map in the barn owl's midbrain.

    PubMed

    Feldman, D E; Knudsen, E I

    1997-09-01

    The map of auditory space in the external nucleus of the inferior colliculus (ICX) of the barn owl is calibrated by visual experience during development. ICX neurons are tuned for interaural time difference (ITD), the owl's primary cue for sound source azimuth, and are arranged into a map of ITD. When vision is altered by rearing owls with prismatic spectacles that shift the visual field in azimuth, ITD tuning in the ICX shifts adaptively. In contrast, ITD tuning remains unchanged in the lateral shell of the central nucleus of the inferior colliculus (ICCls), which provides the principal auditory input to the ICX, suggesting that the projection from the ICCls to the ICX is altered by prism-rearing. In this study, the topography of the ICCls-ICX projection was assessed in normal and prism-reared owls by retrograde labeling using biotinylated dextran amine. In juvenile owls at the age before prism attachment, and in normal adults, labeling patterns were consistent with a topographic projection, with each ICX site receiving input from a restricted region of the ICCls with similar ITD tuning. In prism-reared owls, labeling patterns were systematically altered: each ICX site received additional, abnormal input from a region of the ICCls where ITD tuning matched the shifted ITD tuning of the ICX neurons. These results indicate that anatomical reorganization of the ICCls-ICX projection contributes to the visual calibration of the ICX auditory space map. PMID:9254692

  15. Visual agnosia.

    PubMed

    Álvarez, R; Masjuan, J

    2016-03-01

    Visual agnosia is defined as an impairment of object recognition, in the absence of visual acuity or cognitive dysfunction that would explain this impairment. This condition is caused by lesions in the visual association cortex, sparing primary visual cortex. There are 2 main pathways that process visual information: the ventral stream, tasked with object recognition, and the dorsal stream, in charge of locating objects in space. Visual agnosia can therefore be divided into 2 major groups depending on which of the two streams is damaged. The aim of this article is to conduct a narrative review of the various visual agnosia syndromes, including recent developments in a number of these syndromes. PMID:26358494

  16. Perceived functional impact of abnormal facial appearance.

    PubMed

    Rankin, Marlene; Borah, Gregory L

    2003-06-01

    Functional facial deformities are usually described as those that impair respiration, eating, hearing, or speech. Yet facial scars and cutaneous deformities have a significant negative effect on social functionality that has been poorly documented in the scientific literature. Insurance companies are declining payments for reconstructive surgical procedures for facial deformities caused by congenital disabilities and after cancer or trauma operations that do not affect mechanical facial activity. The purpose of this study was to establish a large, sample-based evaluation of the perceived social functioning, interpersonal characteristics, and employability indices for a range of facial appearances (normal and abnormal). Adult volunteer evaluators (n = 210) provided their subjective perceptions based on facial physical appearance, and an analysis of the consequences of facial deformity on parameters of preferential treatment was performed. A two-group comparative research design rated the differences among 10 examples of digitally altered facial photographs of actual patients among various age and ethnic groups with "normal" and "abnormal" congenital deformities or posttrauma scars. Photographs of adult patients with observable congenital and posttraumatic deformities (abnormal) were digitally retouched to eliminate the stigmatic defects (normal). The normal and abnormal photographs of identical patients were evaluated by the large sample study group on nine parameters of social functioning, such as honesty, employability, attractiveness, and effectiveness, using a visual analogue rating scale. Patients with abnormal facial characteristics were rated as significantly less honest (p = 0.007), less employable (p = 0.001), less trustworthy (p = 0.01), less optimistic (p = 0.001), less effective (p = 0.02), less capable (p = 0.002), less intelligent (p = 0.03), less popular (p = 0.001), and less attractive (p = 0.001) than were the same patients with normal facial

  17. Visual field asymmetries in visual evoked responses

    PubMed Central

    Hagler, Donald J.

    2014-01-01

    Behavioral responses to visual stimuli exhibit visual field asymmetries, but cortical folding and the close proximity of visual cortical areas make electrophysiological comparisons between different stimulus locations problematic. Retinotopy-constrained source estimation (RCSE) uses distributed dipole models simultaneously constrained by multiple stimulus locations to provide separation between individual visual areas that is not possible with conventional source estimation methods. Magnetoencephalography and RCSE were used to estimate time courses of activity in V1, V2, V3, and V3A. Responses to left and right hemifield stimuli were not significantly different. Peak latencies for peripheral stimuli were significantly shorter than those for perifoveal stimuli in V1, V2, and V3A, likely related to the greater proportion of magnocellular input to V1 in the periphery. Consistent with previous results, sensor magnitudes for lower field stimuli were about twice as large as for upper field, which is only partially explained by the proximity to sensors for lower field cortical sources in V1, V2, and V3. V3A exhibited both latency and amplitude differences for upper and lower field responses. There were no differences for V3, consistent with previous suggestions that dorsal and ventral V3 are two halves of a single visual area, rather than distinct areas V3 and VP. PMID:25527151

  18. Central Mechanisms of Abnormal Sympathoexcitation in Chronic Heart Failure

    PubMed Central

    Kishi, Takuya; Hirooka, Yoshitaka

    2012-01-01

    It has been recognized that the sympathetic nervous system is abnormally activated in chronic heart failure, and leads to further worsening chronic heart failure. In the treatment of chronic heart failure many clinical studies have already suggested that the inhibition of the abnormal sympathetic hyperactivity by beta blockers is beneficial. It has been classically considered that abnormal sympathetic hyperactivity in chronic heart failure is caused by the enhancement of excitatory inputs including changes in peripheral baroreceptor and chemoreceptor reflexes and chemical mediators that control sympathetic outflow. Recently, the abnormalities in the central regulation of sympathetic nerve activity mediated by brain renin angiotensin system-oxidative stress axis and/or proinflammatory cytokines have been focused. Central renin angiotensin system, proinflammatory cytokines, and the interaction between them have been determined as the target of the sympathoinhibitory treatment in experimental animal models with chronic heart failure. In conclusion, we must recognize that chronic heart failure is a syndrome with an abnormal sympathoexcitation, which is caused by the abnormalities in the central regulation of sympathetic nerve activity. PMID:22919539

  19. Bilateral Input Protects the Cortex from Unilaterally-Driven Reorganization in Children Who Are Deaf

    ERIC Educational Resources Information Center

    Gordon, Karen A.; Wong, Daniel D. E.; Papsin, Blake C.

    2013-01-01

    Unilateral hearing in childhood restricts input along the bilateral auditory pathways, possibly causing permanent reorganization. In this study we asked: (i) do the auditory pathways develop abnormally in children who are bilaterally deaf and hear with a unilateral cochlear implant? and (ii) can such differences be reversed by restoring input to…

  20. Serial Input Output

    SciTech Connect

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  1. SDR input power estimation algorithms

    NASA Astrophysics Data System (ADS)

    Briones, J. C.; Nappier, J. M.

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  2. SDR Input Power Estimation Algorithms

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  3. Changes in input strength and number are driven by distinct mechanisms at the retinogeniculate synapse

    PubMed Central

    Lin, David J.; Kang, Erin

    2014-01-01

    Recent studies have demonstrated that vision influences the functional remodeling of the mouse retinogeniculate synapse, the connection between retinal ganglion cells and thalamic relay neurons in the dorsal lateral geniculate nucleus (LGN). Initially, each relay neuron receives a large number of weak retinal inputs. Over a 2- to 3-wk developmental window, the majority of these inputs are eliminated, and the remaining inputs are strengthened. This period of refinement is followed by a critical period when visual experience changes the strength and connectivity of the retinogeniculate synapse. Visual deprivation of mice by dark rearing from postnatal day (P)20 results in a dramatic weakening of synaptic strength and recruitment of additional inputs. In the present study we asked whether experience-dependent plasticity at the retinogeniculate synapse represents a homeostatic response to changing visual environment. We found that visual experience starting at P20 following visual deprivation from birth results in weakening of existing retinal inputs onto relay neurons without significant changes in input number, consistent with homeostatic synaptic scaling of retinal inputs. On the other hand, the recruitment of new inputs to the retinogeniculate synapse requires previous visual experience prior to the critical period. Taken together, these findings suggest that diverse forms of homeostatic plasticity drive experience-dependent remodeling at the retinogeniculate synapse. PMID:24848465

  4. Cone inputs to murine striate cortex

    PubMed Central

    Ekesten, Björn; Gouras, Peter

    2008-01-01

    Background We have recorded responses from single neurons in murine visual cortex to determine the effectiveness of the input from the two murine cone photoreceptor mechanisms and whether there is any unique selectivity for cone inputs at this higher region of the visual system that would support the possibility of colour vision in mice. Each eye was stimulated by diffuse light, either 370 (strong stimulus for the ultra-violet (UV) cone opsin) or 505 nm (exclusively stimulating the middle wavelength sensitive (M) cone opsin), obtained from light emitting diodes (LEDs) in the presence of a strong adapting light that suppressed the responses of rods. Results Single cells responded to these diffuse stimuli in all areas of striate cortex. Two types of responsive cells were encountered. One type (135/323 – 42%) had little to no spontaneous activity and responded at either the on and/or the off phase of the light stimulus with a few impulses often of relatively large amplitude. A second type (166/323 – 51%) had spontaneous activity and responded tonically to light stimuli with impulses often of small amplitude. Most of the cells responded similarly to both spectral stimuli. A few (18/323 – 6%) responded strongly or exclusively to one or the other spectral stimulus and rarely in a spectrally opponent manner. Conclusion Most cells in murine striate cortex receive excitatory inputs from both UV- and M-cones. A small fraction shows either strong selectivity for one or the other cone mechanism and occasionally cone opponent responses. Cells that could underlie chromatic contrast detection are present but extremely rare in murine striate cortex. PMID:19014590

  5. Visual hallucinations.

    PubMed

    Collerton, Daniel; Mosimann, Urs Peter

    2010-11-01

    Understanding of visual hallucinations is developing rapidly. Single-factor explanations based on specific pathologies have given way to complex multifactor models with wide potential applicability. Clinical studies of disorders with frequent hallucinations-dementia, delirium, eye disease and psychosis-show that dysfunction within many parts of the distributed ventral object perception system is associated with a range of perceptions from simple flashes and dots to complex formed figures and landscapes. Dissociations between these simple and complex hallucinations indicate at least two hallucinatory syndromes, though exact boundaries need clarification. Neural models of hallucinations variably emphasize the importance of constraints from top down dorsolateral frontal systems, bottom up occipital systems, interconnecting tracts, and thalamic and brainstem regulatory systems. No model has yet gained general acceptance. Both qualitative (a small number of necessary and sufficient constraints) and quantitative explanations (an accumulation of many nonspecific factors) fit existing data. Variable associations of hallucinations with emotional distress and thought disorders across and within pathologies may reflect the roles of cognitive and regulatory systems outside of the purely perceptual. Functional imaging demonstrates that hallucinations and veridical perceptions occur in the same brain areas, intimating a key role for the negotiating interface between top down and bottom up processes. Thus, hallucinations occur when a perception that incorporates a hallucinatory element can provide a better match between predicted and actual sensory input than does a purely veridical experience. Translational research that integrates understandings from clinical hallucinations and basic vision science is likely to be the key to better treatments. WIREs Cogn Sci 2010 1 781-786 For further resources related to this article, please visit the WIREs website. PMID:26271777

  6. What are Visual Data and What Utility Do They Have in Science Education?

    ERIC Educational Resources Information Center

    Finson, Kevin; Pederson, Jon

    2011-01-01

    Visual data differs from visual information since it must be recorded, analyzed, and manipulated in some manner, whereas visual information is primarily sensory input. Our environment is constantly infused with visual inputs, and it is sometimes difficult to make sense of them or to determine how best to deal with them for instructional purposes…

  7. Molecular abnormalities in Ewing's sarcoma.

    PubMed

    Burchill, Susan Ann

    2008-10-01

    Ewing's sarcoma is one of the few solid tumors for which the underlying molecular genetic abnormality has been described: rearrangement of the EWS gene on chromosome 22q12 with an ETS gene family member. These translocations define the Ewing's sarcoma family of tumors (ESFT) and provide a valuable tool for their accurate and unequivocal diagnosis. They also represent ideal targets for the development of tumor-specific therapeutics. Although secondary abnormalities occur in over 80% of primary ESFT the clinical utility of these is currently unclear. However, abnormalities in genes that regulate the G(1)/S checkpoint are frequently described and may be important in predicting outcome and response. Increased understanding of the molecular events that arise in ESFT and their role in the development and maintenance of the malignant phenotype will inform the improved stratification of patients for therapy and identify targets and pathways for the design of more effective cancer therapeutics. PMID:18925858

  8. Visual Scripting.

    ERIC Educational Resources Information Center

    Halas, John

    Visual scripting is the coordination of words with pictures in sequence. This book presents the methods and viewpoints on visual scripting of fourteen film makers, from nine countries, who are involved in animated cinema; it contains concise examples of how a storybook and preproduction script can be prepared in visual terms; and it includes a…

  9. Integrate-and-fire vs Poisson models of LGN input to V1 cortex: noisier inputs reduce orientation selectivity.

    PubMed

    Lin, I-Chun; Xing, Dajun; Shapley, Robert

    2012-12-01

    One of the reasons the visual cortex has attracted the interest of computational neuroscience is that it has well-defined inputs. The lateral geniculate nucleus (LGN) of the thalamus is the source of visual signals to the primary visual cortex (V1). Most large-scale cortical network models approximate the spike trains of LGN neurons as simple Poisson point processes. However, many studies have shown that neurons in the early visual pathway are capable of spiking with high temporal precision and their discharges are not Poisson-like. To gain an understanding of how response variability in the LGN influences the behavior of V1, we study response properties of model V1 neurons that receive purely feedforward inputs from LGN cells modeled either as noisy leaky integrate-and-fire (NLIF) neurons or as inhomogeneous Poisson processes. We first demonstrate that the NLIF model is capable of reproducing many experimentally observed statistical properties of LGN neurons. Then we show that a V1 model in which the LGN input to a V1 neuron is modeled as a group of NLIF neurons produces higher orientation selectivity than the one with Poisson LGN input. The second result implies that statistical characteristics of LGN spike trains are important for V1's function. We conclude that physiologically motivated models of V1 need to include more realistic LGN spike trains that are less noisy than inhomogeneous Poisson processes. PMID:22684587

  10. [Emotion Disorders and Abnormal Perspiration].

    PubMed

    Umeda, Satoshi

    2016-08-01

    This article reviewed the relationship between emotional disorders and abnormal perspiration. First, I focused on local brain areas related to emotional processing, and summarized the functions of the emotional network involving those local areas. Functional disorders followed by the damage in the amygdala, orbitofrontal cortex, and insular cortex were reviewed, including related abnormal perspiration. I then addressed the mechanisms of how autonomic disorders influence emotional processing. Finally, possible future directions for integrated understanding of the connection between neural activities and bodily reactions were discussed. PMID:27503817

  11. Ultrasonographic assessment of abnormal pregnancy.

    PubMed

    England, G C

    1998-07-01

    Ultrasonographic imaging is widely used in small animal practice for the diagnosis of pregnancy and the determination of fetal number. Ultrasonography can also be used to monitor abnormal pregnancies, for example, conceptuses that are poorly developed for their gestational age (and therefore are likely to fail), and pregnancies in which there is embryonic resorption or fetal abortion. An ultrasound examination may reveal fetal abnormalities and therefore alter the management of the pregnant bitch or queen prior to parturition. There are, however, a number of ultrasonographic features of normal pregnancies that may mimic disease, and these must be recognized. PMID:9698618

  12. REL - English Bulk Data Input.

    ERIC Educational Resources Information Center

    Bigelow, Richard Henry

    A bulk data input processor which is available for the Rapidly Extensible Language (REL) English versions is described. In REL English versions, statements that declare names of data items and their interrelationships normally are lines from a terminal or cards in a batch input stream. These statements provide a convenient means of declaring some…

  13. Visual Imagery without Visual Perception?

    ERIC Educational Resources Information Center

    Bertolo, Helder

    2005-01-01

    The question regarding visual imagery and visual perception remain an open issue. Many studies have tried to understand if the two processes share the same mechanisms or if they are independent, using different neural substrates. Most research has been directed towards the need of activation of primary visual areas during imagery. Here we review…

  14. Extracellular Matrix Abnormalities in Schizophrenia

    PubMed Central

    Berretta, Sabina

    2011-01-01

    Emerging evidence points to the involvement of the brain extracellular matrix (ECM) in the pathophysiology of schizophrenia (SZ). Abnormalities affecting several ECM components, including Reelin and chondroitin sulfate proteoglycans (CSPGs), have been described in subjects with this disease. Solid evidence supports the involvement of Reelin, an ECM glycoprotein involved in corticogenesis, synaptic functions and glutamate NMDA receptor regulation, expressed prevalently in distinct populations of GABAergic neurons, which secrete it into the ECM. Marked changes of Reelin expression in SZ have typically been reported in association with GABA-related abnormalities in subjects with SZ and bipolar disorder. Recent findings from our group point to substantial abnormalities affecting CSPGs, a main ECM component, in the amygdala and entorhinal cortex of subjects with schizophrenia, but not bipolar disorder. Striking increases of glial cells expressing CSPGs were accompanied by reductions of perineuronal nets, CSPG- and Reelin-enriched ECM aggregates enveloping distinct neuronal populations. CSPGs developmental and adult functions, including neuronal migration, axon guidance, synaptic and neurotransmission regulation are highly relevant to the pathophysiology of SZ. Together with reports of anomalies affecting several other ECM components, these findings point to the ECM as a key component of the pathology of SZ. We propose that ECM abnormalities may contribute to several aspects of the pathophysiology of this disease, including disrupted connectivity and neuronal migration, synaptic anomalies and altered GABAergic, glutamatergic and dopaminergic neurotransmission. PMID:21856318

  15. Estimating nonstationary input signals from a single neuronal spike train

    NASA Astrophysics Data System (ADS)

    Kim, Hideaki; Shinomoto, Shigeru

    2012-11-01

    Neurons temporally integrate input signals, translating them into timed output spikes. Because neurons nonperiodically emit spikes, examining spike timing can reveal information about input signals, which are determined by activities in the populations of excitatory and inhibitory presynaptic neurons. Although a number of mathematical methods have been developed to estimate such input parameters as the mean and fluctuation of the input current, these techniques are based on the unrealistic assumption that presynaptic activity is constant over time. Here, we propose tracking temporal variations in input parameters with a two-step analysis method. First, nonstationary firing characteristics comprising the firing rate and non-Poisson irregularity are estimated from a spike train using a computationally feasible state-space algorithm. Then, information about the firing characteristics is converted into likely input parameters over time using a transformation formula, which was constructed by inverting the neuronal forward transformation of the input current to output spikes. By analyzing spike trains recorded in vivo, we found that neuronal input parameters are similar in the primary visual cortex V1 and middle temporal area, whereas parameters in the lateral geniculate nucleus of the thalamus were markedly different.

  16. Visual Cortex Plasticity Following Peripheral Damage To The Visual System: fMRI Evidence.

    PubMed

    Lemos, João; Pereira, Daniela; Castelo-Branco, Miguel

    2016-10-01

    Over the last two decades, functional magnetic resonance imaging (fMRI) has become a powerful research method to investigate cortical visual plasticity. Abnormal fMRI response patterns have been occasionally detected in the visually deprived cortex of patients with bilateral retinal diseases. Controversy remains whether these observations indicate structural reorganization of the visual cortex or unmasking of previously silent cortico-cortical connections. In optic nerve diseases, there is weak evidence showing that early visual cortex seems to lack reorganization, while higher-order visual areas undergo plastic changes which may contribute to optimise visual function. There is however accumulating imaging evidence demonstrating trans-synaptic degeneration of the visual cortex in patients with disease of the anterior visual pathways. This may preclude the use of restorative treatments in these patients. Here, we review and update the body of fMRI evidence on visual cortical plasticity. PMID:27542799

  17. Characterization of an energy storage capacitor in abnormal thermal environments

    SciTech Connect

    Edwards, L.R.; Chen, K.C.; Baron, R.V.

    2000-01-05

    There are applications of high-voltage, energy-storage, capacitors where it is desirable that the energy storage capability can be reliably and predictably negated in abnormal environments such as fire. This property serves as a safety feature to prevent events of unintended consequence. The present paper describes studies of the thermal response characteristics of a cylindrically wound, discrete Mylar film/foil capacitor design. The experimental setups that simulate fires will be presented. Three different heat input geometries were employed: uniform radial input, spot radial input, and axial input. Heat input was controlled via feedback system to maintain specific temperature ramp rates. Both capacitor voltage and current were monitored during the thermal excursion to ascertain the failure temperature, i.e. when the capacitor permanently shorts. Temperature of failure data is presented for the three heat input cases along with a statistical analysis of the results and application implications. The physics of failure will be described in terms of the thermal/mechanical properties of the Mylar.

  18. Nonlinear input-output systems

    NASA Technical Reports Server (NTRS)

    Hunt, L. R.; Luksic, Mladen; Su, Renjeng

    1987-01-01

    Necessary and sufficient conditions that the nonlinear system dot-x = f(x) + ug(x) and y = h(x) be locally feedback equivalent to the controllable linear system dot-xi = A xi + bv and y = C xi having linear output are found. Only the single input and single output case is considered, however, the results generalize to multi-input and multi-output systems.

  19. Auto Draw from Excel Input Files

    NASA Technical Reports Server (NTRS)

    Strauss, Karl F.; Goullioud, Renaud; Cox, Brian; Grimes, James M.

    2011-01-01

    The design process often involves the use of Excel files during project development. To facilitate communications of the information in the Excel files, drawings are often generated. During the design process, the Excel files are updated often to reflect new input. The problem is that the drawings often lag the updates, often leading to confusion of the current state of the design. The use of this program allows visualization of complex data in a format that is more easily understandable than pages of numbers. Because the graphical output can be updated automatically, the manual labor of diagram drawing can be eliminated. The more frequent update of system diagrams can reduce confusion and reduce errors and is likely to uncover symmetric problems earlier in the design cycle, thus reducing rework and redesign.

  20. GLIAL ABNORMALITIES IN MOOD DISORDERS

    PubMed Central

    Öngür, Dost; Bechtholt, Anita J.; Carlezon, William A.; Cohen, Bruce M.

    2015-01-01

    Multiple lines of evidence indicate that mood disorders are associated with abnormalities in the brain's cellular composition, especially in glial cells. Considered inert support cells in the past, glial cells are now known to be important for brain function. Treatments for mood disorders enhance glial cell proliferation, and experimental stimulation of cell growth has antidepressant effects in animal models of mood disorders. These findings suggest that the proliferation and survival of glial cells may be important in the pathogenesis of mood disorders and may be possible targets for the development of new treatments. In this chapter, we will review the evidence for glial abnormalities in mood disorders. We will discuss glial cell biology and evidence from postmortem studies of mood disorders. This is not carry out a comprehensive review; rather we selectively discuss existing evidence in building an argument for the role of glial cells in mood disorders. PMID:25377605

  1. Suppressive mechanisms in visual motion processing: From perception to intelligence.

    PubMed

    Tadin, Duje

    2015-10-01

    Perception operates on an immense amount of incoming information that greatly exceeds the brain's processing capacity. Because of this fundamental limitation, the ability to suppress irrelevant information is a key determinant of perceptual efficiency. Here, I will review a series of studies investigating suppressive mechanisms in visual motion processing, namely perceptual suppression of large, background-like motions. These spatial suppression mechanisms are adaptive, operating only when sensory inputs are sufficiently robust to guarantee visibility. Converging correlational and causal evidence links these behavioral results with inhibitory center-surround mechanisms, namely those in cortical area MT. Spatial suppression is abnormally weak in several special populations, including the elderly and individuals with schizophrenia-a deficit that is evidenced by better-than-normal direction discriminations of large moving stimuli. Theoretical work shows that this abnormal weakening of spatial suppression should result in motion segregation deficits, but direct behavioral support of this hypothesis is lacking. Finally, I will argue that the ability to suppress information is a fundamental neural process that applies not only to perception but also to cognition in general. Supporting this argument, I will discuss recent research that shows individual differences in spatial suppression of motion signals strongly predict individual variations in IQ scores. PMID:26299386

  2. Mathematical Visualization

    ERIC Educational Resources Information Center

    Rogness, Jonathan

    2011-01-01

    Advances in computer graphics have provided mathematicians with the ability to create stunning visualizations, both to gain insight and to help demonstrate the beauty of mathematics to others. As educators these tools can be particularly important as we search for ways to work with students raised with constant visual stimulation, from video games…

  3. Visual Literacy

    ERIC Educational Resources Information Center

    Felten, Peter

    2008-01-01

    Living in an image-rich world does not mean students (or faculty and administrators) naturally possess sophisticated visual literacy skills, just as continually listening to an iPod does not teach a person to critically analyze or create music. Instead, "visual literacy involves the ability to understand, produce, and use culturally significant…

  4. Visual Literacy.

    ERIC Educational Resources Information Center

    Lamberski, Richard J.

    A series of articles examines visual literacy from the perspectives of definition, research, curriculum, and resources. Articles examining the definition of visual literacy approach it in terms of semantics, techniques, and exploratory definition areas. There are surveys of present and potential research, and a discussion of the problem of…

  5. Visual Closure.

    ERIC Educational Resources Information Center

    Groffman, Sidney

    An experimental test of visual closure based on an information-theory concept of perception was devised to test the ability to discriminate visual stimuli with reduced cues. The test is to be administered in a timed individual situation in which the subject is presented with sets of incomplete drawings of simple objects that he is required to name…

  6. Visual Thinking.

    ERIC Educational Resources Information Center

    Arnheim, Rudolf

    Based on the more general principle that all thinking (including reasoning) is basically perceptual in nature, the author proposes that visual perception is not a passive recording of stimulus material but an active concern of the mind. He delineates the task of visually distinguishing changes in size, shape, and position and points out the…

  7. Input Type and Parameter Resetting: Is Naturalistic Input Necessary?

    ERIC Educational Resources Information Center

    Rothman, Jason; Iverson, Michael

    2007-01-01

    It has been argued that extended exposure to naturalistic input provides L2 learners with more of an opportunity to converge of target morphosyntactic competence as compared to classroom-only environments, given that the former provide more positive evidence of less salient linguistic properties than the latter (e.g., Isabelli 2004). Implicitly,…

  8. Output, Input Enhancement, and the Noticing Hypothesis: An Experimental Study on ESL Relativization.

    ERIC Educational Resources Information Center

    Izumi, Shinichi

    2002-01-01

    Investigates potentially facilitative effects of internal and external attention-drawing devices--output and visual input enhancement--on acquisition of English relativization by adult English-as-a-Second-Language (ESL) learners. Addresses whether producing output promotes noticing of formal elements in target language input and affects subsequent…

  9. Using State Estimation Residuals to Detect Abnormal SCADA Data

    SciTech Connect

    Ma, Jian; Chen, Yousu; Huang, Zhenyu; Wong, Pak C.

    2010-04-30

    Detection of abnormal supervisory control and data acquisition (SCADA) data is critically important for safe and secure operation of modern power systems. In this paper, a methodology of abnormal SCADA data detection based on state estimation residuals is presented. Preceded with a brief overview of outlier detection methods and bad SCADA data detection for state estimation, the framework of the proposed methodology is described. Instead of using original SCADA measurements as the bad data sources, the residuals calculated based on the results of the state estimator are used as the input for the outlier detection algorithm. The BACON algorithm is applied to the outlier detection task. The IEEE 118-bus system is used as a test base to evaluate the effectiveness of the proposed methodology. The accuracy of the BACON method is compared with that of the 3-σ method for the simulated SCADA measurements and residuals.

  10. Improving the performance of cardiac abnormality detection from PCG signal

    NASA Astrophysics Data System (ADS)

    Sujit, N. R.; Kumar, C. Santhosh; Rajesh, C. B.

    2016-03-01

    The Phonocardiogram (PCG) signal contains important information about the condition of heart. Using PCG signal analysis prior recognition of coronary illness can be done. In this work, we developed a biomedical system for the detection of abnormality in heart and methods to enhance the performance of the system using SMOTE and AdaBoost technique have been presented. Time and frequency domain features extracted from the PCG signal is input to the system. The back-end classifier to the system developed is Decision Tree using CART (Classification and Regression Tree), with an overall classification accuracy of 78.33% and sensitivity (alarm accuracy) of 40%. Here sensitivity implies the precision obtained from classifying the abnormal heart sound, which is an essential parameter for a system. We further improve the performance of baseline system using SMOTE and AdaBoost algorithm. The proposed approach outperforms the baseline system by an absolute improvement in overall accuracy of 5% and sensitivity of 44.92%.

  11. Exploring Ensemble Visualization

    PubMed Central

    Phadke, Madhura N.; Pinto, Lifford; Alabi, Femi; Harter, Jonathan; Taylor, Russell M.; Wu, Xunlei; Petersen, Hannah; Bass, Steffen A.; Healey, Christopher G.

    2012-01-01

    An ensemble is a collection of related datasets. Each dataset, or member, of an ensemble is normally large, multidimensional, and spatio-temporal. Ensembles are used extensively by scientists and mathematicians, for example, by executing a simulation repeatedly with slightly different input parameters and saving the results in an ensemble to see how parameter choices affect the simulation. To draw inferences from an ensemble, scientists need to compare data both within and between ensemble members. We propose two techniques to support ensemble exploration and comparison: a pairwise sequential animation method that visualizes locally neighboring members simultaneously, and a screen door tinting method that visualizes subsets of members using screen space subdivision. We demonstrate the capabilities of both techniques, first using synthetic data, then with simulation data of heavy ion collisions in high-energy physics. Results show that both techniques are capable of supporting meaningful comparisons of ensemble data. PMID:22347540

  12. Abnormal Functional Connectivity Density in Post-traumatic Stress Disorder.

    PubMed

    Zhang, Youxue; Xie, Bing; Chen, Heng; Li, Meiling; Liu, Feng; Chen, Huafu

    2016-05-01

    Post-traumatic stress disorder (PTSD) is a psychiatric disorder that occurs in individuals who have experienced life-threatening mental traumas. Previous neuroimaging studies have indicated that the pathology of PTSD may be associated with the abnormal functional integration among brain regions. In the current study, we used functional connectivity density (FCD) mapping, a novel voxel-wise data-driven approach based on graph theory, to explore aberrant FC through the resting-state functional magnetic resonance imaging of the PTSD. We calculated both short- and long-range FCD in PTSD patients and healthy controls (HCs). Compared with HCs, PTSD patients showed significantly increased long-range FCD in the left dorsolateral prefrontal cortex (DLPFC), but no abnormal short-range FCD was found in PTSD. Furthermore, seed-based FC analysis of the left DLPFC showed increased connectivity in the left superior parietal lobe and visual cortex of PTSD patients. The results suggested that PTSD patients experienced a disruption of intrinsic long-range functional connections in the fronto-parietal network and visual cortex, which are associated with attention control and visual information processing. PMID:26830769

  13. Neocortical Rebound Depolarization Enhances Visual Perception.

    PubMed

    Funayama, Kenta; Minamisawa, Genki; Matsumoto, Nobuyoshi; Ban, Hiroshi; Chan, Allen W; Matsuki, Norio; Murphy, Timothy H; Ikegaya, Yuji

    2015-08-01

    Animals are constantly exposed to the time-varying visual world. Because visual perception is modulated by immediately prior visual experience, visual cortical neurons may register recent visual history into a specific form of offline activity and link it to later visual input. To examine how preceding visual inputs interact with upcoming information at the single neuron level, we designed a simple stimulation protocol in which a brief, orientated flashing stimulus was subsequently coupled to visual stimuli with identical or different features. Using in vivo whole-cell patch-clamp recording and functional two-photon calcium imaging from the primary visual cortex (V1) of awake mice, we discovered that a flash of sinusoidal grating per se induces an early, transient activation as well as a long-delayed reactivation in V1 neurons. This late response, which started hundreds of milliseconds after the flash and persisted for approximately 2 s, was also observed in human V1 electroencephalogram. When another drifting grating stimulus arrived during the late response, the V1 neurons exhibited a sublinear, but apparently increased response, especially to the same grating orientation. In behavioral tests of mice and humans, the flashing stimulation enhanced the detection power of the identically orientated visual stimulation only when the second stimulation was presented during the time window of the late response. Therefore, V1 late responses likely provide a neural basis for admixing temporally separated stimuli and extracting identical features in time-varying visual environments. PMID:26274866

  14. Neocortical Rebound Depolarization Enhances Visual Perception

    PubMed Central

    Funayama, Kenta; Ban, Hiroshi; Chan, Allen W.; Matsuki, Norio; Murphy, Timothy H.; Ikegaya, Yuji

    2015-01-01

    Animals are constantly exposed to the time-varying visual world. Because visual perception is modulated by immediately prior visual experience, visual cortical neurons may register recent visual history into a specific form of offline activity and link it to later visual input. To examine how preceding visual inputs interact with upcoming information at the single neuron level, we designed a simple stimulation protocol in which a brief, orientated flashing stimulus was subsequently coupled to visual stimuli with identical or different features. Using in vivo whole-cell patch-clamp recording and functional two-photon calcium imaging from the primary visual cortex (V1) of awake mice, we discovered that a flash of sinusoidal grating per se induces an early, transient activation as well as a long-delayed reactivation in V1 neurons. This late response, which started hundreds of milliseconds after the flash and persisted for approximately 2 s, was also observed in human V1 electroencephalogram. When another drifting grating stimulus arrived during the late response, the V1 neurons exhibited a sublinear, but apparently increased response, especially to the same grating orientation. In behavioral tests of mice and humans, the flashing stimulation enhanced the detection power of the identically orientated visual stimulation only when the second stimulation was presented during the time window of the late response. Therefore, V1 late responses likely provide a neural basis for admixing temporally separated stimuli and extracting identical features in time-varying visual environments. PMID:26274866

  15. Methods of visualizing graphs

    DOEpatents

    Wong, Pak C.; Mackey, Patrick S.; Perrine, Kenneth A.; Foote, Harlan P.; Thomas, James J.

    2008-12-23

    Methods for visualizing a graph by automatically drawing elements of the graph as labels are disclosed. In one embodiment, the method comprises receiving node information and edge information from an input device and/or communication interface, constructing a graph layout based at least in part on that information, wherein the edges are automatically drawn as labels, and displaying the graph on a display device according to the graph layout. In some embodiments, the nodes are automatically drawn as labels instead of, or in addition to, the label-edges.

  16. The primary visual cortex in the neural circuit for visual orienting

    NASA Astrophysics Data System (ADS)

    Zhaoping, Li

    The primary visual cortex (V1) is traditionally viewed as remote from influencing brain's motor outputs. However, V1 provides the most abundant cortical inputs directly to the sensory layers of superior colliculus (SC), a midbrain structure to command visual orienting such as shifting gaze and turning heads. I will show physiological, anatomical, and behavioral data suggesting that V1 transforms visual input into a saliency map to guide a class of visual orienting that is reflexive or involuntary. In particular, V1 receives a retinotopic map of visual features, such as orientation, color, and motion direction of local visual inputs; local interactions between V1 neurons perform a local-to-global computation to arrive at a saliency map that highlights conspicuous visual locations by higher V1 responses. The conspicuous location are usually, but not always, where visual input statistics changes. The population V1 outputs to SC, which is also retinotopic, enables SC to locate, by lateral inhibition between SC neurons, the most salient location as the saccadic target. Experimental tests of this hypothesis will be shown. Variations of the neural circuit for visual orienting across animal species, with more or less V1 involvement, will be discussed. Supported by the Gatsby Charitable Foundation.

  17. Giant axonal neuropathy: visual and oculomotor deficits.

    PubMed

    Kirkham, T H; Guitton, D; Coupland, S G

    1980-08-01

    Giant axonal neuropathy, a generalised disorder or neurofilaments, presents as a chronic, progressive peripheral neuropathy in childhood. Evidence for central nervous system involvement is demonstrated in this study of four male patients with giant axonal neuropathy who had defective visual function and abnormal ocular motility. The visual system was studied by electroretinography, which showed normal retinal function, and by visual evoked potentials, which showed disease of both optic nerves and retrochiasmal visual pathways. The ocular motility disorder, studied by electrooculography, comprised defective pursuit, inability to maintain eccentric gaze with gaze paretic and rebound nystagmus, abnormal optokinetic responses and failure of suppression of the vestibulo-ocular reflex by fixation. These findings suggested involvement by giant axonal neuropathy of the cerebellar and brain stem pathways important in the control of ocular motility. PMID:7192592

  18. Making chromosome abnormalities treatable conditions.

    PubMed

    Cody, Jannine DeMars; Hale, Daniel Esten

    2015-09-01

    Individuals affected by the classic chromosome deletion syndromes which were first identified at the beginning of the genetic age, are now positioned to benefit from genomic advances. This issue highlights five of these conditions (4p-, 5p-, 11q-, 18p-, and 18q-). It focuses on the increased in understanding of the molecular underpinnings and envisions how these can be transformed into effective treatments. While it is scientifically exciting to see the phenotypic manifestations of hemizygosity being increasingly understood at the molecular and cellular level, it is even more amazing to consider that we are now on the road to making chromosome abnormalities treatable conditions. PMID:26351122

  19. Foot abnormalities of wild birds

    USGS Publications Warehouse

    Herman, C.M.; Locke, L.N.; Clark, G.M.

    1962-01-01

    The various foot abnormalities that occur in birds, including pox, scaly-leg, bumble-foot, ergotism and freezing are reviewed. In addition, our findings at the Patuxent Wildlife Research Center include pox from dove, mockingbird, cowbird, grackle and several species of sparrows. Scaly-leg has been particularly prevalent on icterids. Bumble foot has been observed in a whistling swan and in a group of captive woodcock. Ergotism is reported from a series of captive Canada geese from North Dakota. Several drug treatments recommended by others are presented.

  20. Automated objective characterization of visual field defects in 3D

    NASA Technical Reports Server (NTRS)

    Fink, Wolfgang (Inventor)

    2006-01-01

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

  1. Visual impairment.

    PubMed

    Ellenberger, Carl

    2016-01-01

    This chapter can guide the use of imaging in the evaluation of common visual syndromes: transient visual disturbance, including migraine and amaurosis fugax; acute optic neuropathy complicating multiple sclerosis, neuromyelitis optica spectrum disorder, Leber hereditary optic neuropathy, and Susac syndrome; papilledema and pseudotumor cerebri syndrome; cerebral disturbances of vision, including posterior cerebral arterial occlusion, posterior reversible encephalopathy, hemianopia after anterior temporal lobe resection, posterior cortical atrophy, and conversion blindness. Finally, practical efforts in visual rehabilitation by sensory substitution for blind patients can improve their lives and disclose new information about the brain. PMID:27430448

  2. The advanced LIGO input optics.

    PubMed

    Mueller, Chris L; Arain, Muzammil A; Ciani, Giacomo; DeRosa, Ryan T; Effler, Anamaria; Feldbaum, David; Frolov, Valery V; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J; Kokeyama, Keiko; Korth, William Z; Martin, Rodica M; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H; Tanner, David B; Vorvick, Cheryl; Williams, Luke F; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design. PMID:26827334

  3. The advanced LIGO input optics

    NASA Astrophysics Data System (ADS)

    Mueller, Chris L.; Arain, Muzammil A.; Ciani, Giacomo; DeRosa, Ryan. T.; Effler, Anamaria; Feldbaum, David; Frolov, Valery V.; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J.; Kokeyama, Keiko; Korth, William Z.; Martin, Rodica M.; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H.; Tanner, David B.; Vorvick, Cheryl; Williams, Luke F.; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  4. Signal Prediction With Input Identification

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Chen, Ya-Chin

    1999-01-01

    A novel coding technique is presented for signal prediction with applications including speech coding, system identification, and estimation of input excitation. The approach is based on the blind equalization method for speech signal processing in conjunction with the geometric subspace projection theory to formulate the basic prediction equation. The speech-coding problem is often divided into two parts, a linear prediction model and excitation input. The parameter coefficients of the linear predictor and the input excitation are solved simultaneously and recursively by a conventional recursive least-squares algorithm. The excitation input is computed by coding all possible outcomes into a binary codebook. The coefficients of the linear predictor and excitation, and the index of the codebook can then be used to represent the signal. In addition, a variable-frame concept is proposed to block the same excitation signal in sequence in order to reduce the storage size and increase the transmission rate. The results of this work can be easily extended to the problem of disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. Simulations are included to demonstrate the proposed method.

  5. World Input-Output Network

    PubMed Central

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  6. Regional Hospital Input Price Indexes

    PubMed Central

    Freeland, Mark S.; Schendler, Carol Ellen; Anderson, Gerard

    1981-01-01

    This paper describes the development of regional hospital input price indexes that is consistent with the general methodology used for the National Hospital Input Price Index. The feasibility of developing regional indexes was investigated because individuals inquired whether different regions experienced different rates of increase in hospital input prices. The regional indexes incorporate variations in cost-share weights (the amount an expense category contributes to total spending) associated with hospital type and location, and variations in the rate of input price increases for various regions. We found that between 1972 and 1979 none of the regional price indexes increased at average annual rates significantly different from the national rate. For the more recent period 1977 through 1979, the increase in one Census Region was significantly below the national rate. Further analyses indicated that variations in cost-share weights for various types of hospitals produced no substantial variations in the regional price indexes relative to the national index. We consider these findings preliminary because of limitations in the availability of current, relevant, and reliable data, especially for local area wage rate increases. PMID:10309557

  7. World Input-Output Network.

    PubMed

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  8. Analog Input Data Acquisition Software

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  9. Input/output interface module

    NASA Technical Reports Server (NTRS)

    Ozyazici, E. M.

    1980-01-01

    Module detects level changes in any of its 16 inputs, transfers changes to its outputs, and generates interrupts when changes are detected. Up to four changes-in-state per line are stored for later retrieval by controlling computer. Using standard TTL logic, module fits 19-inch rack-mounted console.

  10. Ocular abnormalities in multi-transfused beta-thalassemia patients

    PubMed Central

    Jafari, Reza; Heydarian, Samira; Karami, Hosein; Shektaei, Mohammad Momeni; Dailami, Kiumars Noruzpour; Amiri, Ahmad Ahmadzadeh; Rezaee, Majid Reza Sheikh; Far, Asad Allah Farrokh

    2015-01-01

    Aims: The aim of this study was to assess ocular changes in thalassemia patients who have received multiple transfusions and chelate binding therapy in order to avoid iron accumulation. Settings and Design: A cross-sectional study. Subjects and Methods: A total of 54 thalassemia major patients were selected as case group, and 54 age- and sex-matched healthy subjects were regarded as a control group. Ocular examination included visual acuity, refraction testing, slit lamp examination, funduscopy, tonometry, perimetry, tear break-up time test, and color vision testing were performed for all the participants. We computed the frequency and duration of blood transfusion, the mean serum ferritin level, pretransfusion hemoglobin concentration, and type, duration, and daily dose of chelation therapy for thalassemia patients based on their records. Statistical Analysis Used: All data analysis was performed using SPSS, version 19. Results: All the thalassemic patients were asymptomatic, but abnormal ocular findings (dry eye (33.3%), cataract (10.2%), retinal pigment epithelium degeneration (16.7%), color vision deficiency (3.7%), and visual field defects (33.7%)) were seen in 68.5% of thalassemic group. The prevalence of ocular abnormalities in normal group was 19.4%, which was significantly lower than that in thalassemia patients (P = 0.000). No significant correlation was found between ocular abnormalities and mean serum ferritin level (P = 0.627) and mean hemoglobin concentration (P = 0.143). Correlation of number of blood transfusion with the presence of ocular abnormalities was found to be statistically significant (P = 0.005). Conclusions: As life expectancy for beta-thalassemia patients extends, regular ophthalmological evaluation to detect early changes in their ocular system is recommended. PMID:26632126

  11. Visual scoring of clots in foremilk.

    PubMed

    Rasmussen, Morten D

    2005-11-01

    The necessary unequivocal and generally accepted definitions of normal and abnormal milk are not available. A precise definition is needed in order for companies to develop sensors to detect and sort abnormal milk at the time of milking. Experts at a workshop defined abnormal milk to be that from cows whose foremilk had changed in homogeneity or was coloured by blood. The objectives of this paper were: firstly, to explore how different groups of people scored the appearance of foremilk; and secondly, to develop a method suitable as an objective reference for testing of manual and automatic detection systems. Consumers, farmers and advisors did not agree on the visual appearance of normal, watery, clotty milk, or milk with blood, and experience is needed to score the visual appearance of foremilk correctly. It seems reasonable to expect a sensitivity of at least 70% for detection of abnormal milk during foremilking. Filter sizes 0.05, 0.07, 0.1, 0.2, 0.5, 1.0, and 2.0 mm were used to filter milk from cows with visually abnormal foremilk. If clots appeared in the foremilk, clots appeared on all size filters, but the filter with pore size 0.1 mm was the easiest to read and work with. The filter method is not reliable in identifying quarters with watery, yellowish, or bloody milk, whereas the method seems consistent, and at least as good as scoring of visual appearance in finding clots in the milk. Clots should show clearly on the filter to be counted as abnormal milk. All clinical cases with clots in the foremilk can be found on the filter and such cases have high somatic cell count (SCC). Both trained and untrained persons using the filter method can score normal and abnormal foremilk with a high specificity (>90%) and a high sensitivity (>80%). The filter method is recommended as a reference for scoring the homogeneity of foremilk. PMID:16223455

  12. Abnormality on Liver Function Test

    PubMed Central

    2013-01-01

    Children with abnormal liver function can often be seen in outpatient clinics or inpatients wards. Most of them have respiratory disease, or gastroenteritis by virus infection, accompanying fever. Occasionally, hepatitis by the viruses causing systemic infection may occur, and screening tests are required. In patients with jaundice, the tests for differential diagnosis and appropriate treatment are important. In the case of a child with hepatitis B virus infection vertically from a hepatitis B surface antigen positive mother, the importance of the recognition of immune clearance can't be overstressed, for the decision of time to begin treatment. Early diagnosis changes the fate of a child with Wilson disease. So, screening test for the disease should not be omitted. Non-alcoholic fatty liver disease, which is mainly discovered in obese children, is a new strong candidate triggering abnormal liver function. Muscular dystrophy is a representative disease mimicking liver dysfunction. Although muscular dystrophy is a progressive disorder, and early diagnosis can't change the fate of patients, it will be better to avoid parent's blame for delayed diagnosis. PMID:24511518

  13. Medical management of abnormal pregnancy.

    PubMed

    Ratnam, S S; Prasad, R N

    1990-06-01

    Medical termination of abnormal pregnancy requires specific techniques since some conditions make therapy more effective, e.g., missed abortion intrauterine death and molar pregnancy, and others less so, e.g. anencephalic pregnancy. In all cases it is best to terminate the pregnancy as soon as possible to reduce anguish and risks of complications such as consumptive coagulopathy. Oxytocin is not consistently effective, but intraamniotic rivanol has oxytocic properties, and prostaglandins (PGs) are effective by several routes. Surgical methods are more popular in Japan and the US. A diagnostic flow chart is included and described. For missed abortion and fetal death vacuum aspiration or dilatation and evacuation are appropriate for early pregnancy, or PGs are used for later pregnancy, unless there are medical contraindications. Anencephalic pregnancy, usually diagnoses in 2nd or 3rd trimester, is resistant to medical therapy and must often be terminated by cesarean section. Molar pregnancy can be managed with vacuum aspiration at any length of gestation, but must be completed by curettage. Intraamniotic PGs are not advised for mole or fetal death. PG analogs can be administered intramuscularly, or vaginally in gel form. Other types of abnormal pregnancy that can be managed with PGs are spina bifida, hydrocephalus, hydrops fetalis, Dandy-Walker syndrome and Down's syndrome. Tubal pregnancy can be evacuated with intratubally administered PGs under laparoscopic control, thereby preserving tubal integrity. PMID:2225605

  14. Visual cognition

    SciTech Connect

    Pinker, S.

    1985-01-01

    This book consists of essays covering issues in visual cognition presenting experimental techniques from cognitive psychology, methods of modeling cognitive processes on computers from artificial intelligence, and methods of studying brain organization from neuropsychology. Topics considered include: parts of recognition; visual routines; upward direction; mental rotation, and discrimination of left and right turns in maps; individual differences in mental imagery, computational analysis and the neurological basis of mental imagery: componental analysis.

  15. Visual Literacy: The Missing Piece of Your Technology Integration Course

    ERIC Educational Resources Information Center

    Sosa, Teri

    2009-01-01

    This article reports the result of an action research study that explored the need for visual literacy as an additional instructional input for students creating technology integration solutions. The introduction of visual literacy concepts is useful in two ways. First, it raises visual considerations to the conscious consideration of students.…

  16. Systems and methods for reconfiguring input devices

    NASA Technical Reports Server (NTRS)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  17. Imaging of Retrochiasmal and Higher Cortical Visual Disorders.

    PubMed

    Tantiwongkosi, Bundhit; Salamon, Noriko

    2015-08-01

    Retrochiasmal visual pathways include optic tracts, lateral geniculate nuclei, optic radiations, and striate cortex (V1). Homonymous hemianopsia and field defect variants with relatively normal visual acuity suggest that the lesions involve retrochiasmal pathways. From V1, visual input is projected to higher visual association areas that are responsible for perception of objects, faces, colors, and orientation. Visual association areas are classified into ventral and dorsal pathways. Damage to the ventral stream results in visual object agnosia, prosopagnosia, and achromatopsia. Balint syndrome, visual inattention, and pure alexia are examples of dorsal stream disorders. Posterior cortical atrophy can involve ventral and dorsal streams, often preceding dementia. PMID:26208417

  18. Visual Data Analysis for Satellites

    NASA Technical Reports Server (NTRS)

    Lau, Yee; Bhate, Sachin; Fitzpatrick, Patrick

    2008-01-01

    The Visual Data Analysis Package is a collection of programs and scripts that facilitate visual analysis of data available from NASA and NOAA satellites, as well as dropsonde, buoy, and conventional in-situ observations. The package features utilities for data extraction, data quality control, statistical analysis, and data visualization. The Hierarchical Data Format (HDF) satellite data extraction routines from NASA's Jet Propulsion Laboratory were customized for specific spatial coverage and file input/output. Statistical analysis includes the calculation of the relative error, the absolute error, and the root mean square error. Other capabilities include curve fitting through the data points to fill in missing data points between satellite passes or where clouds obscure satellite data. For data visualization, the software provides customizable Generic Mapping Tool (GMT) scripts to generate difference maps, scatter plots, line plots, vector plots, histograms, timeseries, and color fill images.

  19. Visual evoked potentials to multiple temporal frequencies. Use in the differential diagnosis of optic neuropathy.

    PubMed

    Bobak, P; Friedman, R; Brigell, M; Goodwin, J; Anderson, R

    1988-07-01

    The usefulness of the visual evoked potential (VEP) in differential diagnosis increases when stimulus parameters such as check size and grating orientation are varied. In this study we varied the stimulation frequency. Temporal frequency-specific abnormalities were compared in three patient categories, including retrobulbar optic neuritis (eight patients), pseudotumor cerebri (11 patients), and thyroid eye disease (seven patients). All patients had minimal clinical evidence of optic nerve damage when tested. A 2.3 cycle-per-degree sinusoidal grating of 55% contrast was phase reversed at either 1 or 4 Hz. The P1 latency of the 1-Hz data and the phase at 8 Hz, the second harmonic of the 4-Hz input frequency, were measured. In retrobulbar neuritis, latency (phase) was severely abnormal at both temporal frequencies. In thyroid eye disease, VEP phase was abnormal at 8 Hz while the P1 latency was normal at 1 Hz. The P1 latency and phase were normal in most cases of pseudotumor cerebri. The results suggest differing mechanisms for damage in compressive vs primary demyelinating neuropathies. PMID:3390057

  20. Contrast Sensitivity versus Visual Evoked Potentials in Multiple Sclerosis

    PubMed Central

    Shandiz, Javad Heravian; Nourian, Abbas; Hossaini, Mercedeh Bahr; Moghaddam, Hadi Ostadi; yekta, Abbas-Ali; Sharifzadeh, Laleh; Marouzi, Parviz

    2010-01-01

    Purpose To compare the Cambridge contrast sensitivity (CS) test and visual evoked potentials (VEP) in detecting visual impairment in a population of visually symptomatic and asymptomatic patients affected by clinically definite multiple sclerosis (MS). Methods Fifty patients (100 eyes) presenting with MS and 25 healthy subjects (50 eyes) with normal corrected visual acuity were included in this study. CS was determined using the Cambridge Low Contrast Grating test and VEP was obtained in all eyes. Findings were evaluated in two age strata of 10–29 and 30–49 years. Results Of the 42 eyes in the 10–29 year age group, CS was abnormal in 22 (52%), VEP was also abnormal in 22 (52%), but only 12 eyes (28%) had visual symptoms. Of the 58 eyes in the 30–49 year group, CS was abnormal in 7 (12%), VEP was abnormal in 34 (58%), while only 11 eyes were symptomatic. No single test could detect all of the abnormal eyes. Conclusion The Cambridge Low Contrast Grating test is useful for detection of clinical and subclinical visual dysfunction especially in young patients with multiple sclerosis. Nevertheless, only a combination of CS and VEP tests can detect most cases of visual dysfunction associated with MS. PMID:22737353

  1. Modular use of peripheral input channels tunes motion-detecting circuitry.

    PubMed

    Silies, Marion; Gohl, Daryl M; Fisher, Yvette E; Freifeld, Limor; Clark, Damon A; Clandinin, Thomas R

    2013-07-10

    In the visual system, peripheral processing circuits are often tuned to specific stimulus features. How this selectivity arises and how these circuits are organized to inform specific visual behaviors is incompletely understood. Using forward genetics and quantitative behavioral studies, we uncover an input channel to motion detecting circuitry in Drosophila. The second-order neuron L3 acts combinatorially with two previously known inputs, L1 and L2, to inform circuits specialized to detect moving light and dark edges. In vivo calcium imaging of L3, combined with neuronal silencing experiments, suggests a neural mechanism to achieve selectivity for moving dark edges. We further demonstrate that different innate behaviors, turning and forward movement, can be independently modulated by visual motion. These two behaviors make use of different combinations of input channels. Such modular use of input channels to achieve feature extraction and behavioral specialization likely represents a general principle in sensory systems. PMID:23849199

  2. Modular use of peripheral input channels tunes motion-detecting circuitry

    PubMed Central

    Silies, Marion; Gohl, Daryl M.; Fisher, Yvette E.; Freifeld, Limor; Clark, Damon A.; Clandinin, Thomas R.

    2013-01-01

    SUMMARY In the visual system, peripheral processing circuits are often tuned to specific stimulus features. How this selectivity arises and how these circuits are organized to inform specific visual behaviors is incompletely understood. Using forward genetics and quantitative behavioral studies, we uncover a new input channel to motion detecting circuitry in Drosophila. The second order neuron L3 acts combinatorially with two previously known inputs, L1 and L2, to inform circuits specialized to detect moving light and dark edges. In vivo calcium imaging of L3, combined with neuronal silencing experiments, suggests a neural mechanism to achieve selectivity for moving dark edges. We further demonstrate that different innate behaviors, turning and forward movement, can be independently modulated by visual motion. These two behaviors make use of different combinations of input channels. Such modular use of input channels to achieve feature extraction and behavioral specialization likely represents a general principle in sensory systems. PMID:23849199

  3. Visual function and perinatal focal cerebral infarction.

    PubMed Central

    Mercuri, E; Atkinson, J; Braddick, O; Anker, S; Nokes, L; Cowan, F; Rutherford, M; Pennock, J; Dubowitz, L

    1996-01-01

    AIMS: To evaluate the visual function of infants with perinatal cerebral infarction in whom the site and size of the lesion has been determined using magnetic resonance imaging (MRI). METHODS: Twelve infants with cerebral infarction on MRI were studied with a battery of tests specifically designed to evaluate visual function in infancy. This included tests: for visual attention (fixation shifts); of cerebral asymmetry (optokinetic nystagmus, visual fields); for assessment of acuity (forced choice preferential looking); and neurophysiological measures of vision (phase reversal and orientation reversal visual evoked potential). RESULTS: A considerable incidence of abnormalities on at least one of the tests for visual function used was observed. The presence or severity of visual abnormalities could not always be predicted by the site and extent of the lesion seen on imaging. CONCLUSIONS: Early focal lesions affecting the visual pathway can, to some extent, be compensated for by the immature developing brain. These data suggest that all the infants presenting with focal lesions need to be investigated with a detailed assessment of various aspects of vision. Images PMID:8949687

  4. Spent fuel behavior under abnormal thermal transients during dry storage

    SciTech Connect

    Stahl, D.; Landow, M.P.; Burian, R.J.; Pasupathi, V.

    1986-01-01

    This study was performed to determine the effects of abnormally high temperatures on spent fuel behavior. Prior to testing, calculations using the CIRFI3 code were used to determine the steady-state fuel and cask component temperatures. The TRUMP code was used to determine transient heating rates under postulated abnormal events during which convection cooling of the cask surfaces was obstructed by a debris bed covering the cask. The peak rate of temperature rise during the first 6 h was calculated to be about 15/sup 0/C/h, followed by a rate of about 1/sup 0/C/h. A Turkey Point spent fuel rod segment was heated to approx. 800/sup 0/C. The segment deformed uniformly with an average strain of 17% at failure and a local strain of 60%. Pretest characterization of the spent fuel consisted of visual examination, profilometry, eddy-current examination, gamma scanning, fission gas collection, void volume measurement, fission gas analysis, hydrogen analysis of the cladding, burnup analysis, cladding metallography, and fuel ceramography. Post-test characterization showed that the failure was a pinhole cladding breach. The results of the tests showed that spent fuel temperatures in excess of 700/sup 0/C are required to produce a cladding breach in fuel rods pressurized to 500 psing (3.45 MPa) under postulated abnormal thermal transient cask conditions. The pinhole cladding breach that developed would be too small to compromise the confinement of spent fuel particles during an abnormal event or after normal cooling conditions are restored. This behavior is similar to that found in other slow ramp tests with irradiated and nonirradiated rod sections and nonirradiated whole rods under conditions that bracketed postulated abnormal heating rates. This similarity is attributed to annealing of the irradiation-strengthened Zircaloy cladding during heating. In both cases, the failure was a benign, ductile pinhole rupture.

  5. Visual and proprioceptive interaction in patients with bilateral vestibular loss.

    PubMed

    Cutfield, Nicholas J; Scott, Gregory; Waldman, Adam D; Sharp, David J; Bronstein, Adolfo M

    2014-01-01

    Following bilateral vestibular loss (BVL) patients gradually adapt to the loss of vestibular input and rely more on other sensory inputs. Here we examine changes in the way proprioceptive and visual inputs interact. We used functional magnetic resonance imaging (fMRI) to investigate visual responses in the context of varying levels of proprioceptive input in 12 BVL subjects and 15 normal controls. A novel metal-free vibrator was developed to allow vibrotactile neck proprioceptive input to be delivered in the MRI system. A high level (100 Hz) and low level (30 Hz) control stimulus was applied over the left splenius capitis; only the high frequency stimulus generates a significant proprioceptive stimulus. The neck stimulus was applied in combination with static and moving (optokinetic) visual stimuli, in a factorial fMRI experimental design. We found that high level neck proprioceptive input had more cortical effect on brain activity in the BVL patients. This included a reduction in visual motion responses during high levels of proprioceptive input and differential activation in the midline cerebellum. In early visual cortical areas, the effect of high proprioceptive input was present for both visual conditions but in lateral visual areas, including V5/MT, the effect was only seen in the context of visual motion stimulation. The finding of a cortical visuo-proprioceptive interaction in BVL patients is consistent with behavioural data indicating that, in BVL patients, neck afferents partly replace vestibular input during the CNS-mediated compensatory process. An fMRI cervico-visual interaction may thus substitute the known visuo-vestibular interaction reported in normal subject fMRI studies. The results provide evidence for a cortical mechanism of adaptation to vestibular failure, in the form of an enhanced proprioceptive influence on visual processing. The results may provide the basis for a cortical mechanism involved in proprioceptive substitution of vestibular

  6. Visual and proprioceptive interaction in patients with bilateral vestibular loss☆

    PubMed Central

    Cutfield, Nicholas J.; Scott, Gregory; Waldman, Adam D.; Sharp, David J.; Bronstein, Adolfo M.

    2014-01-01

    Following bilateral vestibular loss (BVL) patients gradually adapt to the loss of vestibular input and rely more on other sensory inputs. Here we examine changes in the way proprioceptive and visual inputs interact. We used functional magnetic resonance imaging (fMRI) to investigate visual responses in the context of varying levels of proprioceptive input in 12 BVL subjects and 15 normal controls. A novel metal-free vibrator was developed to allow vibrotactile neck proprioceptive input to be delivered in the MRI system. A high level (100 Hz) and low level (30 Hz) control stimulus was applied over the left splenius capitis; only the high frequency stimulus generates a significant proprioceptive stimulus. The neck stimulus was applied in combination with static and moving (optokinetic) visual stimuli, in a factorial fMRI experimental design. We found that high level neck proprioceptive input had more cortical effect on brain activity in the BVL patients. This included a reduction in visual motion responses during high levels of proprioceptive input and differential activation in the midline cerebellum. In early visual cortical areas, the effect of high proprioceptive input was present for both visual conditions but in lateral visual areas, including V5/MT, the effect was only seen in the context of visual motion stimulation. The finding of a cortical visuo-proprioceptive interaction in BVL patients is consistent with behavioural data indicating that, in BVL patients, neck afferents partly replace vestibular input during the CNS-mediated compensatory process. An fMRI cervico-visual interaction may thus substitute the known visuo-vestibular interaction reported in normal subject fMRI studies. The results provide evidence for a cortical mechanism of adaptation to vestibular failure, in the form of an enhanced proprioceptive influence on visual processing. The results may provide the basis for a cortical mechanism involved in proprioceptive substitution of vestibular

  7. Abnormalities of the Erythrocyte Membrane

    PubMed Central

    Gallagher, Patrick G.

    2014-01-01

    Synopsis Primary abnormalities of the erythrocyte membrane, including the hereditary spherocytosis and hereditary elliptocytosis syndromes, are an important group of inherited hemolytic anemias. Classified by distinctive morphology on peripheral blood smear, these disorders are characterized by clinical, laboratory, and genetic heterogeneity. Among this group, hereditary spherocytosis patients are more likely to experience symptomatic anemia. Treatment of hereditary spherocytosis with splenectomy is curative in most patients. Once considered routine, growing recognition of the longterm risks of splenectomy, including cardiovascular disease, thrombotic disorders, and pulmonary hypertension, as well as the emergence of penicillin-resistant pneumococci, a concern for infection in overwhelming postsplenectomy infection, have led to re-evaluation of the role of splenectomy. Current management guidelines acknowledge these important considerations when entertaining splenectomy and recommend detailed discussion between health care providers, patient, and family. The hereditary elliptocytosis syndromes are the most common primary disorders of erythrocyte membrane proteins. However, most elliptocytosis patients are asymptomatic and do not require therapy. PMID:24237975

  8. Grid Visualization Tool

    NASA Technical Reports Server (NTRS)

    Chouinard, Caroline; Fisher, Forest; Estlin, Tara; Gaines, Daniel; Schaffer, Steven

    2005-01-01

    The Grid Visualization Tool (GVT) is a computer program for displaying the path of a mobile robotic explorer (rover) on a terrain map. The GVT reads a map-data file in either portable graymap (PGM) or portable pixmap (PPM) format, representing a gray-scale or color map image, respectively. The GVT also accepts input from path-planning and activity-planning software. From these inputs, the GVT generates a map overlaid with one or more rover path(s), waypoints, locations of targets to be explored, and/or target-status information (indicating success or failure in exploring each target). The display can also indicate different types of paths or path segments, such as the path actually traveled versus a planned path or the path traveled to the present position versus planned future movement along a path. The program provides for updating of the display in real time to facilitate visualization of progress. The size of the display and the map scale can be changed as desired by the user. The GVT was written in the C++ language using the Open Graphics Library (OpenGL) software. It has been compiled for both Sun Solaris and Linux operating systems.

  9. Visual integration in autism

    PubMed Central

    Smith, Danielle; Ropar, Danielle; Allen, Harriet A.

    2015-01-01

    Atypical integration is a topic of debate in the autism literature. Some theories suggest that altered perception in autism spectrum disorder (ASD) is due to a failure to integrate information from meaningful context into the final percept, whereas others suggest that integration of low-level features is impaired. Empirical research which forms the basis for these theories has failed to account for higher-level influences not inherent in the stimuli (i.e., instructions and goals) and assess integration at both lower and higher perceptual levels within the same task. Here, we describe how perceived expectations and goals of a task can modulate the processing of low-level visual input via the medial prefrontal cortex (mPFC). We then go on to illustrate how future research might assess the relative contribution of both low and high-level processes using the same paradigm. We conclude by recommending that when results appear conflicting, consideration of the relative strength of low-level input vs. feedback or high-level processes may prove helpful. Importantly, research in this area needs to more broadly consider the various influences on perception, and find better ways to assess the contributions of early and later visual processes. PMID:26190994

  10. Adults with Chromosome 18 Abnormalities.

    PubMed

    Soileau, Bridgette; Hasi, Minire; Sebold, Courtney; Hill, Annice; O'Donnell, Louise; Hale, Daniel E; Cody, Jannine D

    2015-08-01

    The identification of an underlying chromosome abnormality frequently marks the endpoint of a diagnostic odyssey. However, families are frequently left with more questions than answers as they consider their child's future. In the case of rare chromosome conditions, a lack of longitudinal data often makes it difficult to provide anticipatory guidance to these families. The objective of this study is to describe the lifespan, educational attainment, living situation, and behavioral phenotype of adults with chromosome 18 abnormalities. The Chromosome 18 Clinical Research Center has enrolled 483 individuals with one of the following conditions: 18q-, 18p-, Tetrasomy 18p, and Ring 18. As a part of the ongoing longitudinal study, we collect data on living arrangements, educational level attained, and employment status as well as data on executive functioning and behavioral skills on an annual basis. Within our cohort, 28 of the 483 participants have died, the majority of whom have deletions encompassing the TCF4 gene or who have unbalanced rearrangement involving other chromosomes. Data regarding the cause of and age at death are presented. We also report on the living situation, educational attainment, and behavioral phenotype of the 151 participants over the age of 18. In general, educational level is higher for people with all these conditions than implied by the early literature, including some that received post-high school education. In addition, some individuals are able to live independently, though at this point they represent a minority of patients. Data on executive function and behavioral phenotype are also presented. Taken together, these data provide insight into the long-term outcome for individuals with a chromosome 18 condition. This information is critical in counseling families on the range of potential outcomes for their child. PMID:25403900

  11. National Hospital Input Price Index

    PubMed Central

    Freeland, Mark S.; Anderson, Gerard; Schendler, Carol Ellen

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 percent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies. PMID:10309052

  12. Neuroanatomical Visualization of the Impaired Striatal Connectivity in Huntington's Disease Mouse Model.

    PubMed

    Kim, Dohee; Jeon, Jeha; Cheong, Eunji; Kim, Dong Jin; Ryu, Hoon; Seo, Hyemyung; Kim, Yun Kyung

    2016-05-01

    Huntington's disease (HD) is a movement disorder characterized by the early selective degeneration of striatum. For motor control, the striatum receives excitatory inputs from multiple brain regions and projects the information to other basal ganglia nuclei. Despite the pathological importance of the striatal degeneration in HD, there are little anatomical data that show impaired striatal connectivity in HD. For the anatomical mapping of the striatum, we injected here a neurotracer DiD to the dorsal striatum of HD mouse model (YAC128). Compared with littermate controls, the number of the traced inputs to the striatum was reduced dramatically in YAC128 mice at 12 months of age suggesting massive destruction of the striatal connections. Basal ganglia inputs were significantly damaged in HD mice by showing 61 % decrease in substantia nigra pars compacta, 85% decrease in thalamic centromedian nucleus, and 55% decrease in thalamic parafascicular nucleus. Cortical inputs were also greatly decreased by 43% in motor cortex, 48% in somatosensory cortex, and 72% in visual cortex. Besides the known striatal connections, the neurotracer DiD also traced inputs from amygdala and the amygdala inputs were decreased by 68% in YAC128 mice. Considering the role of amygdala in emotion processing, the impairment in amygdalostriatal connectivity strongly suggests that emotional disturbances could occur in HD mice. Indeed, open-field tests further indicated that YAC128 mice exhibited changes in emotional behaviors related to symptoms of depression and anxiety. Although onset of HD is clinically determined on the basis of motor abnormality, emotional deficits are also common features of the disease. Therefore, our anatomical connectivity mapping of the striatum provides a new insight to interpret brain dysfunction in HD. PMID:25976370

  13. Visual outcome in children with congenital hemiplegia: correlation with MRI findings.

    PubMed

    Mercuri, E; Spanò, M; Bruccini, G; Frisone, M F; Trombetta, J C; Blandino, A; Longo, M; Guzzetta, F

    1996-08-01

    Fourteen children with congenital hemiplegia were studied with a detailed assessment of various aspects of vision (linear acuity, stereopsis, visual fields) and MRI. The aim of this study was to evaluate the effect of a congenital lesion on visual function. The results showed a very high incidence (78%) of children who had abnormal results on at least one of the visual tests. Visual abnormalities were not correlated with the clinical severity of hemiplegia or with a specific pattern of lesion on MRI. Similarly no constant association could be found between visual structures (optic radiations and primary visual cortex) and visual function. Finally, our results would suggest that all the children with congenital hemiplegia need to be investigated irrespective of the clinical severity or of the type or the extent of the lesion. This would help to identify children with minor visual abnormalities which can affect everyday life performance. PMID:8892366

  14. Visual Prosthesis

    PubMed Central

    Schiller, Peter H.; Tehovnik, Edward J.

    2009-01-01

    There are more than 40 million blind individuals in the world whose plight would be greatly ameliorated by creating a visual prosthetic. We begin by outlining the basic operational characteristics of the visual system as this knowledge is essential for producing a prosthetic device based on electrical stimulation through arrays of implanted electrodes. We then list a series of tenets that we believe need to be followed in this effort. Central among these is our belief that the initial research in this area, which is in its infancy, should first be carried out in animals. We suggest that implantation of area V1 holds high promise as the area is of a large volume and can therefore accommodate extensive electrode arrays. We then proceed to consider coding operations that can effectively convert visual images viewed by a camera to stimulate electrode arrays to yield visual impressions that can provide shape, motion and depth information. We advocate experimental work that mimics electrical stimulation effects non-invasively in sighted human subjects using a camera from which visual images are converted into displays on a monitor akin to those created by electrical stimulation. PMID:19065857

  15. Visual stability

    PubMed Central

    Melcher, David

    2011-01-01

    Our vision remains stable even though the movements of our eyes, head and bodies create a motion pattern on the retina. One of the most important, yet basic, feats of the visual system is to correctly determine whether this retinal motion is owing to real movement in the world or rather our own self-movement. This problem has occupied many great thinkers, such as Descartes and Helmholtz, at least since the time of Alhazen. This theme issue brings together leading researchers from animal neurophysiology, clinical neurology, psychophysics and cognitive neuroscience to summarize the state of the art in the study of visual stability. Recently, there has been significant progress in understanding the limits of visual stability in humans and in identifying many of the brain circuits involved in maintaining a stable percept of the world. Clinical studies and new experimental methods, such as transcranial magnetic stimulation, now make it possible to test the causal role of different brain regions in creating visual stability and also allow us to measure the consequences when the mechanisms of visual stability break down. PMID:21242136

  16. Inguinal Abnormalities in Male Patients with Acetabular Fractures Treated Using an Ilioinguinal Exposure

    PubMed Central

    Firoozabadi, Reza; Stafford, Paul; Routt, Milton

    2015-01-01

    Background: Surgeons performing an ilioinguinal exposure for acetabular fracture surgery need to be aware of aberrant findings such as inguinal hernias and spermatic cord lesions. The purpose of this study is to report these occurrences in a clinical series of adult males undergoing acetabular fracture fixation and a series of adult male cadavers. The secondary aim is to characterize these abnormalities to aid surgeons in detecting these abnormalities preoperatively and coordinating a surgical plan with a general surgeon. Methods: Clinical study- Retrospective review of treated acetabular fractures through an ilioinguinal approach. Incidence of inguinal canal and spermatic cord abnormalities requiring general surgery consultation were identified. Corresponding CT scans were reviewed and radiographic characteristics of the spermatic cord abnormalities and/or hernias were noted. Cadaveric study- 18 male cadavers dissected bilaterally using an ilioinguinal exposure. The inguinal canal and the contents of the spermatic cord were identified and characterized. Results: Clinical Study- 5.7% (5/87) of patients had spermatic cord lesion and/or inguinal hernia requiring general surgical intervention. Preoperative pelvic CT scan review identified abnormalities noted intraoperatively in four of the five patients. Cord lipomas visualized as enlargements of the spermatic cord with homogeneous density. Hernias visualized as enlarged spermatic cords with heterogeneous density. Cadaver Study- 31% (11/36) of cadavers studied had spermatic cord and/or inguinal canal abnormalities. Average cord diameter in those with abnormalities was 24.9 mm (15-28) compared to 16 mm (11-22) in normal cords, which was statistically significant. Discussion: The clinical and cadaveric findings emphasize the importance of understanding inguinal abnormalities and the value of detecting them preoperatively. The preoperative pelvic CT scans were highly sensitive in detecting inguinal abnormalities. PMID

  17. A new quantitative indicator of visual fatigue

    NASA Technical Reports Server (NTRS)

    Goussard, Yves; Martin, Bernard; Stark, Lawrence

    1987-01-01

    Ocular-motor correlates of visual fatigue have remained elusive. Performance of ocular-motor tracking with a wide-band white noise input and the response of the dual-mode, smooth pursuit-saccadic eye movement system as output was used to test visual fatigue. A new visual fatigue indicator, VFI, was defined as the nonlinear remnant after subtracting an identified impulse response contribution to the output. Subjects were required to perform very fatiguing CRT screen reading tasks, and the VFI correlated well with the subjective reports of visual fatigue.

  18. Breathing abnormalities in sleep in achondroplasia.

    PubMed Central

    Waters, K A; Everett, F; Sillence, D; Fagan, E; Sullivan, C E

    1993-01-01

    Overnight sleep studies were performed in 20 subjects with achondroplasia to document further the respiratory abnormalities present in this group. Somatosensory evoked potentials (SEPs) were recorded in 19 of the subjects to screen for the presence of brainstem abnormalities, which are one of the potential aetiological mechanisms. Fifteen children aged 1 to 14 years, and five young adults, aged 20 to 31 years were included. All had upper airway obstruction and 15 (75%) had a pathological apnoea index (greater than five per hour). Other sleep associated respiratory abnormalities, including partial obstruction, central apnoea, and abnormal electromyographic activity of accessory muscles of respiration, also showed a high prevalence. SEPs were abnormal in eight (42%), but there was no correlation between abnormal SEPs and apnoea during sleep, either qualitatively or quantitatively. A high prevalence of both sleep related respiratory abnormalities and abnormal SEPs in young subjects with achondroplasia was demonstrated. However, the sleep related respiratory abnormalities do not always result in significant blood gas disturbances or correlate with abnormal SEPs in this group. PMID:8215519

  19. Multiperspective Focus+Context Visualization.

    PubMed

    Wu, Meng-Lin; Popescu, Voicu

    2016-05-01

    Occlusions are a severe bottleneck for the visualization of large and complex datasets. Conventional images only show dataset elements to which there is a direct line of sight, which significantly limits the information bandwidth of the visualization. Multiperspective visualization is a powerful approach for alleviating occlusions to show more than what is visible from a single viewpoint. However, constructing and rendering multiperspective visualizations is challenging. We present a framework for designing multiperspective focus+context visualizations with great flexibility by manipulating the underlying camera model. The focus region viewpoint is adapted to alleviate occlusions. The framework supports multiperspective visualization in three scenarios. In a first scenario, the viewpoint is altered independently for individual image regions to avoid occlusions. In a second scenario, conventional input images are connected into a multiperspective image. In a third scenario, one or several data subsets of interest (i.e., targets) are visualized where they would be seen in the absence of occluders, as the user navigates or the targets move. The multiperspective images are rendered at interactive rates, leveraging the camera model's fast projection operation. We demonstrate the framework on terrain, urban, and molecular biology geometric datasets, as well as on volume rendered density datasets. PMID:27045911

  20. Comparative measurement of visual stability in Earth and cosmic space (L-4)

    NASA Technical Reports Server (NTRS)

    Koga, Kazugo

    1993-01-01

    object motion velocity. The VOR is constantly simulated under 1-g conditions on Earth. In fact, human beings have been habituated and 'programmed' for orientation (visual stability) in their everyday, 1-g environment. When humans are exposed to a different gravity situation, this programmed behavior must change; that is, it is reprogrammed. This is called habituation or familiarization. We hope to examine how object motion perception is perturbed and subsequently adapted in the microgravity environment. This experiment is focused on the cooperation of visual, vestibular, and somatosensory perception coordination and how it is changed or reduced in space compared to 1-g environment. We will obtain information on the coordination between eye movement and neck muscle activity by using EOG and EMG. We will also collect data from Payload Specialists using a self-diagnostic questionnaire concerned with perceptual abnormality. When each sensory input function and its integration in the higher nervous system are well-characterized, then more effective techniques to control SAS may be developed.

  1. Visually Guided Step Descent in Children with Williams Syndrome

    ERIC Educational Resources Information Center

    Cowie, Dorothy; Braddick, Oliver; Atkinson, Janette

    2012-01-01

    Individuals with Williams syndrome (WS) have impairments in visuospatial tasks and in manual visuomotor control, consistent with parietal and cerebellar abnormalities. Here we examined whether individuals with WS also have difficulties in visually controlling whole-body movements. We investigated visual control of stepping down at a change of…

  2. FMRI of visual working memory in high school football players.

    PubMed

    Shenk, Trey E; Robinson, Meghan E; Svaldi, Diana O; Abbas, Kausar; Breedlove, Katherine M; Leverenz, Larry J; Nauman, Eric A; Talavage, Thomas M

    2015-01-01

    Visual working memory deficits have been observed in at-risk athletes. This study uses a visual N-back working memory functional magnetic resonance imaging task to longitudinally assess asymptomatic football athletes for abnormal activity. Athletes were increasingly "flagged" as the season progressed. Flagging may provide early detection of injury. PMID:25961587

  3. Tactile Gap Detection Deteriorates during Bimanual Symmetrical Movements under Mirror Visual Feedback

    PubMed Central

    Bultitude, Janet H.; Juravle, Georgiana; Spence, Charles

    2016-01-01

    It has been suggested that incongruence between signals for motor intention and sensory input can cause pain and other sensory abnormalities. This claim is supported by reports that moving in an environment of induced sensorimotor conflict leads to elevated pain and sensory symptoms in those with certain painful conditions. Similar procedures can lead to reports of anomalous sensations in healthy volunteers too. In the present study, we used mirror visual feedback to investigate the effects of sensorimotor incongruence on responses to stimuli that arise from sources external to the body, in particular, touch. Incongruence between the sensory and motor signals for the right arm was manipulated by having the participants make symmetrical or asymmetrical movements while watching a reflection of their left arm in a parasagittal mirror, or the left hand surface of a similarly positioned opaque board. In contrast to our prediction, sensitivity to the presence of gaps in tactile stimulation of the right forearm was not reduced when participants made asymmetrical movements during mirror visual feedback, as compared to when they made symmetrical or asymmetrical movements with no visual feedback. Instead, sensitivity was reduced when participants made symmetrical movements during mirror visual feedback relative to the other three conditions. We suggest that small discrepancies between sensory and motor information, as they occur during mirror visual feedback with symmetrical movements, can impair tactile processing. In contrast, asymmetrical movements with mirror visual feedback may not impact tactile processing because the larger discrepancies between sensory and motor information may prevent the integration of these sources of information. These results contrast with previous reports of anomalous sensations during exposure to both low and high sensorimotor conflict, but are nevertheless in agreement with a forward model interpretation of perceptual modulations during goal

  4. Tactile Gap Detection Deteriorates during Bimanual Symmetrical Movements under Mirror Visual Feedback.

    PubMed

    Bultitude, Janet H; Juravle, Georgiana; Spence, Charles

    2016-01-01

    It has been suggested that incongruence between signals for motor intention and sensory input can cause pain and other sensory abnormalities. This claim is supported by reports that moving in an environment of induced sensorimotor conflict leads to elevated pain and sensory symptoms in those with certain painful conditions. Similar procedures can lead to reports of anomalous sensations in healthy volunteers too. In the present study, we used mirror visual feedback to investigate the effects of sensorimotor incongruence on responses to stimuli that arise from sources external to the body, in particular, touch. Incongruence between the sensory and motor signals for the right arm was manipulated by having the participants make symmetrical or asymmetrical movements while watching a reflection of their left arm in a parasagittal mirror, or the left hand surface of a similarly positioned opaque board. In contrast to our prediction, sensitivity to the presence of gaps in tactile stimulation of the right forearm was not reduced when participants made asymmetrical movements during mirror visual feedback, as compared to when they made symmetrical or asymmetrical movements with no visual feedback. Instead, sensitivity was reduced when participants made symmetrical movements during mirror visual feedback relative to the other three conditions. We suggest that small discrepancies between sensory and motor information, as they occur during mirror visual feedback with symmetrical movements, can impair tactile processing. In contrast, asymmetrical movements with mirror visual feedback may not impact tactile processing because the larger discrepancies between sensory and motor information may prevent the integration of these sources of information. These results contrast with previous reports of anomalous sensations during exposure to both low and high sensorimotor conflict, but are nevertheless in agreement with a forward model interpretation of perceptual modulations during goal

  5. Spreading Photoparoxysmal EEG Response is Associated with an Abnormal Cortical Excitability Pattern

    ERIC Educational Resources Information Center

    Siniatchkin, Michael; Groppa, Sergey; Jerosch, Bettina; Muhle, Hiltrud; Kurth, Christoph; Shepherd, Alex J.; Siebner, Hartwig; Stephani, Ulrich

    2007-01-01

    Photosensitivity or photoparoxysmal response (PPR) is a highly heritable electroencephalographic trait characterized by an abnormal cortical response to intermittent photic stimulation (IPS). In PPR-positive individuals, IPS induces spikes, spike-waves or intermittent slow waves. The PPR may be restricted to posterior visual areas (i.e. local PPR…

  6. Executive function abnormalities in pathological gamblers

    PubMed Central

    2008-01-01

    Background Pathological gambling (PG) is an impulse control disorder characterized by persistent and maladaptive gambling behaviors with disruptive consequences for familial, occupational and social functions. The pathophysiology of PG is still unclear, but it is hypothesized that it might include environmental factors coupled with a genetic vulnerability and dysfunctions of different neurotransmitters and selected brain areas. Our study aimed to evaluate a group of patients suffering from PG by means of some neuropsychological tests in order to explore the brain areas related to the disorder. Methods Twenty outpatients (15 men, 5 women), with a diagnosis of PG according to DSM-IV criteria, were included in the study and evaluated with a battery of neuropsychological tests: the Wisconsin Card Sorting Test (WCST), the Wechsler Memory Scale revised (WMS-R) and the Verbal Associative Fluency Test (FAS). The results obtained in the patients were compared with normative values of matched healthy control subjects. Results The PG patients showed alterations at the WCST only, in particular they had a great difficulty in finding alternative methods of problem-solving and showed a decrease, rather than an increase, in efficiency, as they progressed through the consecutive phases of the test. The mean scores of the other tests were within the normal range. Conclusion Our findings showed that patients affected by PG, in spite of normal intellectual, linguistic and visual-spatial abilities, had abnormalities emerging from the WCST, in particular they could not learn from their mistakes and look for alternative solutions. Our results would seem to confirm an altered functioning of the prefrontal areas which might provoke a sort of cognitive "rigidity" that might predispose to the development of impulsive and/or compulsive behaviors, such as those typical of PG. PMID:18371193

  7. Sensory experience modifies feature map relationships in visual cortex.

    PubMed

    Cloherty, Shaun L; Hughes, Nicholas J; Hietanen, Markus A; Bhagavatula, Partha S; Goodhill, Geoffrey J; Ibbotson, Michael R

    2016-01-01

    The extent to which brain structure is influenced by sensory input during development is a critical but controversial question. A paradigmatic system for studying this is the mammalian visual cortex. Maps of orientation preference (OP) and ocular dominance (OD) in the primary visual cortex of ferrets, cats and monkeys can be individually changed by altered visual input. However, the spatial relationship between OP and OD maps has appeared immutable. Using a computational model we predicted that biasing the visual input to orthogonal orientation in the two eyes should cause a shift of OP pinwheels towards the border of OD columns. We then confirmed this prediction by rearing cats wearing orthogonally oriented cylindrical lenses over each eye. Thus, the spatial relationship between OP and OD maps can be modified by visual experience, revealing a previously unknown degree of brain plasticity in response to sensory input. PMID:27310531

  8. Sensory experience modifies feature map relationships in visual cortex

    PubMed Central

    Cloherty, Shaun L; Hughes, Nicholas J; Hietanen, Markus A; Bhagavatula, Partha S

    2016-01-01

    The extent to which brain structure is influenced by sensory input during development is a critical but controversial question. A paradigmatic system for studying this is the mammalian visual cortex. Maps of orientation preference (OP) and ocular dominance (OD) in the primary visual cortex of ferrets, cats and monkeys can be individually changed by altered visual input. However, the spatial relationship between OP and OD maps has appeared immutable. Using a computational model we predicted that biasing the visual input to orthogonal orientation in the two eyes should cause a shift of OP pinwheels towards the border of OD columns. We then confirmed this prediction by rearing cats wearing orthogonally oriented cylindrical lenses over each eye. Thus, the spatial relationship between OP and OD maps can be modified by visual experience, revealing a previously unknown degree of brain plasticity in response to sensory input. DOI: http://dx.doi.org/10.7554/eLife.13911.001 PMID:27310531

  9. The Temporal Dynamics of Visual Processing in Multiple Sclerosis.

    PubMed

    Lopes Costa, Silvana; Gonçalves, Oscar F; DeLuca, John; Chiaravalloti, Nancy; Chakravarthi, Ramakrishna; Almeida, Jorge

    2016-01-01

    Although the integrity of the visual system is often affected in multiple sclerosis (MS), the potential relationship between the temporal dynamics of visual processing and performance on neuropsychological tests assessing processing speed (PS) remains relatively unexplored. Here, we test if a PS deficit is related to abnormalities within the visual system, rather than impaired higher-level cognitive function. Two groups of participants with MS (1 group with PS deficits and another without) and a healthy control group, matched for age and education, were included. To explore the temporal dynamics of visual processing, we used 2 psychophysical paradigms: attention enhancement/prioritization and rapid serial visual presentation. Visual PS deficits were associated with a decreased capability to detect visual stimuli and a higher limitation in visual temporal-processing capacity. These results suggest that a latent sensorial temporal limitation of the visual system is significantly associated to PS deficits in MS. PMID:26508328

  10. 22q11 chromosome abnormalities and the cleft service.

    PubMed

    Nugent, N; McGillivary, A; Earley, M J

    2010-04-01

    Deletion of chromosome 22q11 gives rise to a spectrum of anomalies, including cleft palate. These are grouped together as the DiGeorge or velocardiofacial syndrome. Patients with this chromosomal abnormality account for a small, but noteworthy proportion of patients attending our cleft service. They frequently have other significant comorbidities consistent with their diagnosis. Over a ten-year period, 16 patients within our cleft service have been diagnosed, using chromosome analysis, as having deletions at 22q11. All had either a cleft palate and/or velopharyngeal incompetence, for which they underwent repair of the cleft palate or pharyngoplasty. Several have required secondary palate surgery following initial palate surgery. Poor quality of speech was the indication for secondary procedures in the majority of cases. Fourteen of the 16 have other comorbidities, ranging from congenital heart disease to ocular abnormalities. In addition, 15 of the 16 have developmental delays and/or learning difficulties. Other specialties, such as ENT, cardiology, genetics and ophthalmology have been involved in the care of all these patients. Although comprising only a small proportion of patients attending a cleft team, the diagnosis of this chromosomal abnormality is significant, as these patients may require substantial input of resources and the expertise of several specialties. Early recognition of features of this entity and diagnosis can aid more efficient intervention. PMID:19249264

  11. Autonomous detection of heart sound abnormalities using an auscultation jacket.

    PubMed

    Visagie, C; Scheffer, C; Lubbe, W W; Doubell, A F

    2009-12-01

    This paper presents a study using an auscultation jacket with embedded electronic stethoscopes, and a software classification system capable of differentiating between normal and certain auscultatory abnormalities. The aim of the study is to demonstrate the potential of such a system for semi-automated diagnosis for underserved locations, for instance in rural areas or in developing countries where patients far outnumber the available medical personnel. Using an "auscultation jacket", synchronous data was recorded at multiple chest locations on 31 healthy volunteers and 21 patients with heart pathologies. Electrocardiograms (ECGs) were also recorded simultaneously with phonocardiographic data. Features related to heart pathologies were extracted from the signals and used as input to a feed-forward artificial neural network. The system is able to classify between normal and certain abnormal heart sounds with a sensitivity of 84% and a specificity of 86%. Though the number of training and testing samples presented are limited, the system performed well in differentiating between normal and abnormal heart sounds in the given database of available recordings. The results of this study demonstrate the potential of such a system to be used as a fast and cost-effective screening tool for heart pathologies. PMID:20169844

  12. Making memories: the development of long-term visual knowledge in children with visual agnosia.

    PubMed

    Metitieri, Tiziana; Barba, Carmen; Pellacani, Simona; Viggiano, Maria Pia; Guerrini, Renzo

    2013-01-01

    There are few reports about the effects of perinatal acquired brain lesions on the development of visual perception. These studies demonstrate nonseverely impaired visual-spatial abilities and preserved visual memory. Longitudinal data analyzing the effects of compromised perceptions on long-term visual knowledge in agnosics are limited to lesions having occurred in adulthood. The study of children with focal lesions of the visual pathways provides a unique opportunity to assess the development of visual memory when perceptual input is degraded. We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2  years and 3.7  years from the initial assessment. All children exhibited apperceptive visual agnosia and visual memory impairment. We observed a longitudinal improvement of visual memory modulated by the structural properties of objects. Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment. PMID:24319599

  13. Transient uniocular visual loss on deviation of the eye in association with intraorbital tumours.

    PubMed

    Bradbury, P G; Levy, I S; McDonald, W I

    1987-05-01

    Five patients with unilateral orbital tumours are described in whom transient loss of vision occurred on deviation of the affected eye from the primary position. Other presenting features were diplopia, proptosis, poor visual acuity, visual field defects, pupillary abnormalities, fundal changes and altered colour vision. Abnormalities on fluorescein angiography suggest that the visual loss is due to transient ischaemia. Temporary uniocular loss of vision on eye movement may be an early sign of an intra-orbital mass. PMID:3035104

  14. Transient uniocular visual loss on deviation of the eye in association with intraorbital tumours.

    PubMed Central

    Bradbury, P G; Levy, I S; McDonald, W I

    1987-01-01

    Five patients with unilateral orbital tumours are described in whom transient loss of vision occurred on deviation of the affected eye from the primary position. Other presenting features were diplopia, proptosis, poor visual acuity, visual field defects, pupillary abnormalities, fundal changes and altered colour vision. Abnormalities on fluorescein angiography suggest that the visual loss is due to transient ischaemia. Temporary uniocular loss of vision on eye movement may be an early sign of an intra-orbital mass. Images PMID:3035104

  15. Visual evoked potentials in infants and children.

    PubMed

    Taylor, M J; McCulloch, D L

    1992-07-01

    Visual evoked potential (VEP) studies are of great value in a wide variety of pediatric patients, including those with disorders of the sensory visual pathway and those at risk for visual pathway damage. VEPs are simple, non-invasive, and are particularly appropriate for infants and young children who cannot communicate visual symptoms or cooperate for standard vision assessment. VEPs in pediatric patients have the following main purposes: (1) detecting lesions causing dysfunction of the sensory visual pathways (the VEP is a sensitive indicator of subclinical lesions and can be used to differentiate visual impairment from visual inattention in young infants); (2) confirming functional loss when disorders of the visual system are present; (3) quantifying visual impairment in patients with known visual disorders, accomplished either empirically by noting the severity of the VEP abnormality to flash and pattern stimuli or by visual acuity estimation studies (early quantification of vision loss allows referral to early intervention programs, which can ameliorate the long-term consequences of the disability); (4) monitoring patients who are at risk for visual complications either from diseases (such as hydrocephalus or neurofibromatosis) or as a complication of therapeutic intervention (e.g., neurosurgery, chemotherapy) to help detect and avoid long-term sequelae of such therapies on the developing nervous system; (5) establishing prognosis for visual and systemic recovery based on flash VEPs for specific pediatric disorders including perinatal asphyxia in full-term neonates, acute-onset cortical blindness, and, to a fair extent, in comatose children; and (6) in some cases, contributing to the differential diagnosis. Abnormalities of flash and/or pattern VEPs are generally nonspecific to the type of exact location of the lesion, except in distinguishing prefrom postchiasmal lesions. However, in certain conditions, such as the hereditary ataxias of childhood, VEP

  16. Dynamics of visually guided auditory plasticity in the optic tectum of the barn owl.

    PubMed

    Brainard, M S; Knudsen, E I

    1995-02-01

    1. In the optic tectum of normal barn owls, bimodal (auditory-visual) neurons are tuned to the values of interaural time difference (ITD) that are produced by sounds at the locations of their visual receptive fields (VRFs). The auditory tuning of tectal neurons is actively guided by visual experience during development: in the tectum of adult owls reared with an optically displaced visual field, neurons are tuned to abnormal values of ITD that are close to the values produced by sounds at the locations of their optically displaced VRFs. In this study we investigated the dynamics of this experience-dependent plasticity. 2. Owls were raised from shortly after eye-opening (14-22 days of age) with prismatic spectacles that displaced the visual field to the right or left. Starting at approximately 60 days of age, multiunit recordings were made to assess the tuning of tectal neurons to ITD presented via earphones. In the earliest recording sessions (ages 60-80 days), ITD tuning was often close to normal, even though the majority of the owls' previous experience was with an altered correspondence between ITD values and VRF locations. Subsequently, over a period of weeks, responses to the normal range of ITDs were gradually eliminated while responses to values of ITD corresponding with the optically displaced VRF were acquired. 3. At intermediate stages in this process, the ITD tuning at many sites became abnormally broad, so that responses were simultaneously present to both normal values of ITD and to values corresponding with the optically displaced VRF. At this stage the latencies and durations of newly acquired responses systematically exceeded the latencies and durations of the responses to normal values of ITD. 4. Dynamic changes in ITD tuning similar to those recorded in the optic tectum also occurred in the external nucleus of the inferior colliculus (ICX), which provides the major source of ascending auditory input to the tectum. 5. These results suggest the

  17. Visualizing inequality

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo

    2016-07-01

    The study of socioeconomic inequality is of substantial importance, scientific and general alike. The graphic visualization of inequality is commonly conveyed by Lorenz curves. While Lorenz curves are a highly effective statistical tool for quantifying the distribution of wealth in human societies, they are less effective a tool for the visual depiction of socioeconomic inequality. This paper introduces an alternative to Lorenz curves-the hill curves. On the one hand, the hill curves are a potent scientific tool: they provide detailed scans of the rich-poor gaps in human societies under consideration, and are capable of accommodating infinitely many degrees of freedom. On the other hand, the hill curves are a powerful infographic tool: they visualize inequality in a most vivid and tangible way, with no quantitative skills that are required in order to grasp the visualization. The application of hill curves extends far beyond socioeconomic inequality. Indeed, the hill curves are highly effective 'hyperspectral' measures of statistical variability that are applicable in the context of size distributions at large. This paper establishes the notion of hill curves, analyzes them, and describes their application in the context of general size distributions.

  18. Biochemical abnormalities in Pearson syndrome.

    PubMed

    Crippa, Beatrice Letizia; Leon, Eyby; Calhoun, Amy; Lowichik, Amy; Pasquali, Marzia; Longo, Nicola

    2015-03-01

    Pearson marrow-pancreas syndrome is a multisystem mitochondrial disorder characterized by bone marrow failure and pancreatic insufficiency. Children who survive the severe bone marrow dysfunction in childhood develop Kearns-Sayre syndrome later in life. Here we report on four new cases with this condition and define their biochemical abnormalities. Three out of four patients presented with failure to thrive, with most of them having normal development and head size. All patients had evidence of bone marrow involvement that spontaneously improved in three out of four patients. Unique findings in our patients were acute pancreatitis (one out of four), renal Fanconi syndrome (present in all patients, but symptomatic only in one), and an unusual organic aciduria with 3-hydroxyisobutyric aciduria in one patient. Biochemical analysis indicated low levels of plasma citrulline and arginine, despite low-normal ammonia levels. Regression analysis indicated a significant correlation between each intermediate of the urea cycle and the next, except between ornithine and citrulline. This suggested that the reaction catalyzed by ornithine transcarbamylase (that converts ornithine to citrulline) might not be very efficient in patients with Pearson syndrome. In view of low-normal ammonia levels, we hypothesize that ammonia and carbamylphosphate could be diverted from the urea cycle to the synthesis of nucleotides in patients with Pearson syndrome and possibly other mitochondrial disorders. PMID:25691415

  19. Semen abnormalities with SSRI antidepressants.

    PubMed

    2015-01-01

    Despite decades of widespread use, the adverse effect profile of "selective" serotonin reuptake inhibitor (SSRI) antidepressants has still not been fully elucidated. Studies in male animals have shown delayed sexual development and reduced fertility. Three prospective cohort studies conducted in over one hundred patients exposed to an SSRI for periods ranging from 5 weeks to 24 months found altered semen param-eters after as little as 3 months of exposure: reduced sperm concentration, reduced sperm motility, a higher percentage of abnormal spermatozoa, and increased levels of sperm DNA fragmentation. One clinical trial showed growth retardation in children considered depressed who were exposed to SSRls. SSRls may have endocrine disrupting properties. Dapoxetine is a short-acting serotonin reuptake inhibitor that is chemically related to fluoxetine and marketed in the European Union for men complaining of premature ejaculation. But the corresponding European summary of product characteristics does not mention any effects on fertility. In practice, based on the data available as of mid-2014, the effects of SSRI exposure on male fertility are unclear. However, it is a risk that should be taken into account and pointed out to male patients who would like to father a child or who are experiencing fertility problems. PMID:25729824

  20. The XXXXY Sex Chromosome Abnormality

    PubMed Central

    Barr, M. L.; Carr, D. H.; Pozsonyi, J.; Wilson, R. A.; Dunn, H. G.; Jacobson, T. S.; Miller, J. R.; Chown, B.

    1962-01-01

    The most common sex chromosome complex in sex chromatin-positive males with Klinefelter's syndrome is XXY. When the complex is XXYY or XXXY, the clinical findings do not seem to differ materially from those seen in XXY subjects, although more patients with these intersexual chromosome complements need to be studied to establish possible phenotypical expressions of the chromosomal variants. Two male children with an XXXXY sex chromosome abnormality are described. The data obtained from the study of these cases and five others described in the literature suggest that the XXXXY patient is likely to have congenital defects not usually seen in the common form of the Klinefelter syndrome. These include a triad of (1) skeletal anomalies (including radioulnar synostosis), (2) hypogenitalism (hypoplasia of penis and scrotum, incomplete descent of testes and defective prepubertal development of seminiferous tubules), and (3) greater risk of severe mental deficiency. That the conclusions are based on data from a small number of patients is emphasized, together with the need for a cytogenetic survey of a large control or unselected population. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10 PMID:13969480

  1. Abnormal Mitochondrial Dynamics and Neurodegenerative Diseases

    PubMed Central

    Su, Bo; Wang, Xinglong; Zheng, Ling; Perry, George; Smith, Mark A.; Zhu, Xiongwei

    2009-01-01

    Mitochondrial dysfunction is a prominent feature of various neurodegenerative diseases. A deeper understanding of the remarkably dynamic nature of mitochondria, characterized by a delicate balance of fission and fusion, has helped to fertilize a recent wave of new studies demonstrating abnormal mitochondrial dynamics in neurodegenerative diseases. This review highlights mitochondrial dysfunction and abnormal mitochondrial dynamics in Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, and Huntington disease and discusses how these abnormal mitochondrial dynamics may contribute to mitochondrial and neuronal dysfunction. We propose that abnormal mitochondrial dynamics represents a key common pathway that mediates or amplifies mitochondrial dysfunction and neuronal dysfunction during the course of neurodegeneration. PMID:19799998

  2. Chromosomal abnormalities in child psychiatric patients.

    PubMed

    Hong, K E; Kim, J H; Moon, S Y; Oh, S K

    1999-08-01

    To determine the frequency of chromosomal abnormalities in a child psychiatric population, and to evaluate possible associations between types of abnormalities and patient's clinical characteristics, cytogenetic examination was performed on 604 patients. Demographic data, reasons for karyotyping, clinical signs, and other patient characteristics were assessed and correlated with the results from karyotyping. Chromosomal abnormalities were found in 69 patients (11.3%); these were structural in 49 cases and numerical in 20. Inversion of chromosome nine was found in 15 subjects, trisomy of chromosome 21 in 11, and fragile X in five patients. When karyotyping was performed because of intellectual impairment or multiple developmental delay, significantly more abnormalities were found than average; when performed because autistic disorder was suspected, the number of abnormalities was significantly fewer. There were no differences in clinical variables between structural and numerical abnormalities, nor among nine types of chromosomal abnormalities, except that numerical abnormalities and polymorphism were found at a later age, and that walking was more delayed and IQ was lower in patients with Down syndrome. Clinicians should be aware of the possible presence of chromosomal abnormalities in child psychiatric populations; the close collaboration with geneticists and the use of more defined guidelines for cytogenetic investigation are important. PMID:10485616

  3. Radiologic atlas of pulmonary abnormalities in children

    SciTech Connect

    Singleton, E.B.; Wagner, M.L.; Dutton, R.V.

    1988-01-01

    This book is an atlas about thoracic abnormalities in infants and children. The authors include computed tomographic, digital subtraction angiographic, ultrasonographic, and a few magnetic resonance (MR) images. They recognize and discuss how changes in the medical treatment of premature infants and the management of infection and pediatric tumors have altered some of the appearances and considerations in these diseases. Oriented toward all aspects of pulmonary abnormalities, the book starts with radiographic techniques and then discusses the normal chest, the newborn, infections, tumors, and pulmonary vascular diseases. There is comprehensive treatment of mediastinal abnormalities and a discussion of airway abnormalities.

  4. Early abnormalities in transgenic mouse models of amyotrophic lateral sclerosis.

    PubMed

    Durand, Jacques; Amendola, Julien; Bories, Cyril; Lamotte d'Incamps, Boris

    2006-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative and fatal human disorder characterized by progressive loss of motor neurons. Transgenic mouse models of ALS are very useful to study the initial mechanisms underlying this neurodegenerative disease. We will focus here on the earlier abnormalities observed in superoxide dismutase 1 (SOD1) mutant mice. Several hypotheses have been advanced to explain the selective loss of motor neurons such as apoptosis, neurofilament disorganisation, oxidative stress, mitochondrial dysfunction, astrogliosis and excitotoxicity. Although disease onset appears at adulthood, recent studies have detected abnormalities during embryonic and postnatal maturation in animal models of ALS. We reported that SOD1(G85R) mutant mice exhibit specific delays in acquiring sensory-motor skills during the first week after birth. In addition, physiological measurements on in vitro spinal cord preparations reveal defects in evoking rhythmic activity with N-methyl-DL-aspartate and serotonin at lumbar, but not sacral roots. This is potentially significant, as functions involving sacral roots are spared at late stages of the disease. Moreover, electrical properties of SOD1 lumbar motoneurons are altered as early as the second postnatal week when mice begin to walk. Alterations concern the input resistance and the gain of SOD1 motoneurons which are lower than in control motoneurons. Whether or not the early changes in discharge firing are responsible for the uncoupling between motor axon terminals and muscles is still an open question. A link between these early electrical abnormalities and the late degeneration of motoneurons is proposed in this short review. Our data suggest that ALS, as other neurodegenerative diseases, could be a consequence of an abnormal development of neurons and network properties. We hypothesize that the SOD1 mutation could induce early changes during the period of maturation of motor systems and that compensatory mechanisms

  5. Transformation priming helps to disambiguate sudden changes of sensory inputs.

    PubMed

    Pastukhov, Alexander; Vivian-Griffiths, Solveiga; Braun, Jochen

    2015-11-01

    Retinal input is riddled with abrupt transients due to self-motion, changes in illumination, object-motion, etc. Our visual system must correctly interpret each of these changes to keep visual perception consistent and sensitive. This poses an enormous challenge, as many transients are highly ambiguous in that they are consistent with many alternative physical transformations. Here we investigated inter-trial effects in three situations with sudden and ambiguous transients, each presenting two alternative appearances (rotation-reversing structure-from-motion, polarity-reversing shape-from-shading, and streaming-bouncing object collisions). In every situation, we observed priming of transformations as the outcome perceived in earlier trials tended to repeat in subsequent trials and this repetition was contingent on perceptual experience. The observed priming was specific to transformations and did not originate in priming of perceptual states preceding a transient. Moreover, transformation priming was independent of attention and specific to low level stimulus attributes. In summary, we show how "transformation priors" and experience-driven updating of such priors helps to disambiguate sudden changes of sensory inputs. We discuss how dynamic transformation priors can be instantiated as "transition energies" in an "energy landscape" model of the visual perception. PMID:26416529

  6. Distributed visualization framework architecture

    NASA Astrophysics Data System (ADS)

    Mishchenko, Oleg; Raman, Sundaresan; Crawfis, Roger

    2010-01-01

    An architecture for distributed and collaborative visualization is presented. The design goals of the system are to create a lightweight, easy to use and extensible framework for reasearch in scientific visualization. The system provides both single user and collaborative distributed environment. System architecture employs a client-server model. Visualization projects can be synchronously accessed and modified from different client machines. We present a set of visualization use cases that illustrate the flexibility of our system. The framework provides a rich set of reusable components for creating new applications. These components make heavy use of leading design patterns. All components are based on the functionality of a small set of interfaces. This allows new components to be integrated seamlessly with little to no effort. All user input and higher-level control functionality interface with proxy objects supporting a concrete implementation of these interfaces. These light-weight objects can be easily streamed across the web and even integrated with smart clients running on a user's cell phone. The back-end is supported by concrete implementations wherever needed (for instance for rendering). A middle-tier manages any communication and synchronization with the proxy objects. In addition to the data components, we have developed several first-class GUI components for visualization. These include a layer compositor editor, a programmable shader editor, a material editor and various drawable editors. These GUI components interact strictly with the interfaces. Access to the various entities in the system is provided by an AssetManager. The asset manager keeps track of all of the registered proxies and responds to queries on the overall system. This allows all user components to be populated automatically. Hence if a new component is added that supports the IMaterial interface, any instances of this can be used in the various GUI components that work with this

  7. An Abnormal Psychology Community Based Interview Assignment

    ERIC Educational Resources Information Center

    White, Geoffry D.

    1977-01-01

    A course option in abnormal psychology involves students in interviewing and observing the activities of individuals in the off-campus community who are concerned with some aspect of abnormal psychology. The technique generates student interest in the field when they interview people about topics such as drug abuse, transsexualism, and abuse of…

  8. Detection of Structural Abnormalities Using Neural Nets

    NASA Technical Reports Server (NTRS)

    Zak, M.; Maccalla, A.; Daggumati, V.; Gulati, S.; Toomarian, N.

    1996-01-01

    This paper describes a feed-forward neural net approach for detection of abnormal system behavior based upon sensor data analyses. A new dynamical invariant representing structural parameters of the system is introduced in such a way that any structural abnormalities in the system behavior are detected from the corresponding changes to the invariant.

  9. Immune Abnormalities in Patients with Autism.

    ERIC Educational Resources Information Center

    Warren, Reed P.; And Others

    1986-01-01

    A study of 31 autistic patients (3-28 years old) has revealed several immune-system abnormalities, including decreased numbers of T lymphocytes and an altered ratio of helper-to-suppressor T cells. Immune-system abnormalities may be directly related to underlying biologic processes of autism or an indirect reflection of the actual pathologic…

  10. Nail abnormalities in patients with vitiligo*

    PubMed Central

    Topal, Ilteris Oguz; Gungor, Sule; Kocaturk, Ozgur Emek; Duman, Hatice; Durmuscan, Mustafa

    2016-01-01

    Background Vitiligo is an acquired pigmentary skin disorder affecting 0.1-4% of the general population. The nails may be affected in patients with an autoimmune disease such as psoriasis, and in those with alopecia areata. It has been suggested that nail abnormalities should be apparent in vitiligo patients. Objective We sought to document the frequency and clinical presentation of nail abnormalities in vitiligo patients compared to healthy volunteers. We also examined the correlations between nail abnormalities and various clinical parameters. Methods This study included 100 vitiligo patients and 100 healthy subjects. Full medical histories were collected from the subjects, who underwent thorough general and nail examinations. All nail changes were noted. In the event of clinical suspicion of a fungal infection, additional mycological investigations were performed. Results Nail abnormalities were more prevalent in the patients (78%) than in the controls (55%) (p=0.001). Longitudinal ridging was the most common finding (42%), followed by (in descending order): leukonychia, an absent lunula, onycholysis, nail bed pallor, onychomycosis, splinter hemorrhage and nail plate thinning. The frequency of longitudinal ridging was significantly higher in patients than in controls (p<0.001). Conclusions Nail abnormalities were more prevalent in vitiligo patients than in controls. Systematic examination of the nails in such patients is useful because nail abnormalities are frequent. However, the causes of such abnormalities require further study. Longitudinal ridging and leukonychia were the most common abnormalities observed in this study. PMID:27579738

  11. Visualizing Progress

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Reality Capture Technologies, Inc. is a spinoff company from Ames Research Center. Offering e-business solutions for optimizing management, design and production processes, RCT uses visual collaboration environments (VCEs) such as those used to prepare the Mars Pathfinder mission.The product, 4-D Reality Framework, allows multiple users from different locations to manage and share data. The insurance industry is one targeted commercial application for this technology.

  12. Flow visualization

    NASA Astrophysics Data System (ADS)

    Weinstein, Leonard M.

    Flow visualization techniques are reviewed, with particular attention given to those applicable to liquid helium flows. Three techniques capable of obtaining qualitative and quantitative measurements of complex 3D flow fields are discussed including focusing schlieren, particle image volocimetry, and holocinematography (HCV). It is concluded that the HCV appears to be uniquely capable of obtaining full time-varying, 3D velocity field data, but is limited to the low speeds typical of liquid helium facilities.

  13. Flow visualization

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.

    1991-01-01

    Flow visualization techniques are reviewed, with particular attention given to those applicable to liquid helium flows. Three techniques capable of obtaining qualitative and quantitative measurements of complex 3D flow fields are discussed including focusing schlieren, particle image volocimetry, and holocinematography (HCV). It is concluded that the HCV appears to be uniquely capable of obtaining full time-varying, 3D velocity field data, but is limited to the low speeds typical of liquid helium facilities.

  14. Early visual processing for low spatial frequency fearful face is correlated with cortical volume in patients with schizophrenia.

    PubMed

    Lee, Jung Suk; Park, Gewnhi; Song, Myeong Ju; Choi, Kee-Hong; Lee, Seung-Hwan

    2016-01-01

    Patients with schizophrenia present with dysfunction of the magnocellular pathway, which might impair their early visual processing. We explored the relationship between functional abnormality of early visual processing and brain volumetric changes in schizophrenia. Eighteen patients and 16 healthy controls underwent electroencephalographic recordings and high-resolution magnetic resonance imaging. During electroencephalographic recordings, participants passively viewed neutral or fearful faces with broad, high, or low spatial frequency characteristics. Voxel-based morphometry was performed to investigate brain volume correlates of visual processing deficits. Event related potential analysis suggested that patients with schizophrenia had relatively impaired P100 processing of low spatial frequency fearful face stimuli compared with healthy controls; patients' gray-matter volumes in the dorsolateral and medial prefrontal cortices positively correlated with this amplitude. In addition, patients' gray-matter volume in the right cuneus positively correlated with the P100 amplitude in the left hemisphere for the high spatial frequency neutral face condition and that in the left dorsolateral prefrontal cortex negatively correlated with the negative score of the Positive and Negative Syndrome Scale. No significant correlations were observed in healthy controls. This study suggests that the cuneus and prefrontal cortex are significantly involved with the early visual processing of magnocellular input in patients with schizophrenia. PMID:26730192

  15. [Abnormality in bone metabolism after burn].

    PubMed

    Gong, X; Xie, W G

    2016-08-20

    Burn causes bone metabolic abnormality in most cases, including the changes in osteoblasts and osteoclasts, bone mass loss, and bone absorption, which results in decreased bone mineral density. These changes are sustainable for many years after burn and even cause growth retardation in burned children. The mechanisms of bone metabolic abnormality after burn include the increasing glucocorticoids due to stress response, a variety of cytokines and inflammatory medium due to inflammatory response, vitamin D deficiency, hypoparathyroidism, and bone loss due to long-term lying in bed. This article reviews the pathogenesis and regularity of bone metabolic abnormality after burn, the relationship between bone metabolic abnormality and burn area/depth, and the treatment of bone metabolic abnormality, etc. and discusses the research directions in the future. PMID:27562160

  16. M-Stream Deficits and Reading-Related Visual Processes in Developmental Dyslexia

    ERIC Educational Resources Information Center

    Boden, Catherine; Giaschi, Deborah

    2007-01-01

    Some visual processing deficits in developmental dyslexia have been attributed to abnormalities in the subcortical M stream and/or the cortical dorsal stream of the visual pathways. The nature of the relationship between these visual deficits and reading is unknown. The purpose of the present article was to characterize reading-related perceptual…

  17. Finite Element Results Visualization for Unstructured Grids

    SciTech Connect

    Speck, Douglas E.; Dovey, Donald J.

    1996-07-15

    GRIZ is a general-purpose post-processing application supporting interactive visualization of finite element analysis results on unstructured grids. In addition to basic pseudocolor renderings of state variables over the mesh surface, GRIZ provides modern visualization techniques such as isocontours and isosurfaces, cutting planes, vector field display, and particle traces. GRIZ accepts both command-line and mouse-driven input, and is portable to virtually any UNIX platform which provides Motif and OpenGl libraries.

  18. Oculo-Visual Dysfunction in Parkinson’s Disease

    PubMed Central

    Armstrong, R.A.

    2015-01-01

    This review describes the oculo-visual problems likely to be encountered in Parkinson’s disease (PD) with special reference to three questions: (1) are there visual symptoms characteristic of the prodromal phase of PD, (2) is PD dementia associated with specific visual changes, and (3) can visual symptoms help in the differential diagnosis of the parkinsonian syndromes, viz. PD, progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and corticobasal degeneration (CBD)? Oculo-visual dysfunction in PD can involve visual acuity, dynamic contrast sensitivity, colour discrimination, pupil reactivity, eye movement, motion perception, and visual processing speeds. In addition, disturbance of visuo-spatial orientation, facial recognition problems, and chronic visual hallucinations may be present. Prodromal features of PD may include autonomic system dysfunction potentially affecting pupil reactivity, abnormal colour vision, abnormal stereopsis associated with postural instability, defects in smooth pursuit eye movements, and deficits in visuo-motor adaptation, especially when accompanied by idiopathic rapid eye movement (REM) sleep behaviour disorder. PD dementia is associated with the exacerbation of many oculo-visual problems but those involving eye movements, visuo-spatial function, and visual hallucinations are most characteristic. Useful diagnostic features in differentiating the parkinsonian symptoms are the presence of visual hallucinations, visuo-spatial problems, and variation in saccadic eye movement dysfunction. PMID:26599301

  19. Repositioning Recitation Input in College English Teaching

    ERIC Educational Resources Information Center

    Xu, Qing

    2009-01-01

    This paper tries to discuss how recitation input helps overcome the negative influences on the basis of second language acquisition theory and confirms the important role that recitation input plays in improving college students' oral and written English.

  20. Processing of Visual Imagery by an Adaptive Model of the Visual System: Its Performance and its Significance. Final Report, June 1969-March 1970.

    ERIC Educational Resources Information Center

    Tallman, Oliver H.

    A digital simulation of a model for the processing of visual images is derived from known aspects of the human visual system. The fundamental principle of computation suggested by a biological model is a transformation that distributes information contained in an input stimulus everywhere in a transform domain. Each sensory input contributes under…

  1. VGC ANALYZER: A SOFTWARE FOR STATISTICAL ANALYSIS OF FULLY CROSSED MULTIPLE-READER MULTIPLE-CASE VISUAL GRADING CHARACTERISTICS STUDIES.

    PubMed

    Båth, Magnus; Hansson, Jonny

    2016-06-01

    Visual grading characteristics (VGC) analysis is a non-parametric rank-invariant method for analysis of visual grading data. In VGC analysis, image quality ratings for two different conditions are compared by producing a VGC curve, similar to how the ratings for normal and abnormal cases in receiver operating characteristic (ROC) analysis are used to create an ROC curve. The use of established ROC software for the analysis of VGC data has therefore previously been proposed. However, the ROC analysis is based on the assumption of independence between normal and abnormal cases. In VGC analysis, this independence cannot always be assumed, e.g. if the ratings are based on the same patients imaged under both conditions. A dedicated software intended for analysis of VGC studies, which takes possible dependencies between ratings into account in the statistical analysis of a VGC study, has therefore been developed. The software-VGC Analyzer-determines the area under the VGC curve and its uncertainty using non-parametric resampling techniques. This article gives an introduction to VGC Analyzer, describes the types of analyses that can be performed and instructs the user about the input and output data. PMID:26769908

  2. Flight Test Validation of Optimal Input Design and Comparison to Conventional Inputs

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    1997-01-01

    A technique for designing optimal inputs for aerodynamic parameter estimation was flight tested on the F-18 High Angle of Attack Research Vehicle (HARV). Model parameter accuracies calculated from flight test data were compared on an equal basis for optimal input designs and conventional inputs at the same flight condition. In spite of errors in the a priori input design models and distortions of the input form by the feedback control system, the optimal inputs increased estimated parameter accuracies compared to conventional 3-2-1-1 and doublet inputs. In addition, the tests using optimal input designs demonstrated enhanced design flexibility, allowing the optimal input design technique to use a larger input amplitude to achieve further increases in estimated parameter accuracy without departing from the desired flight test condition. This work validated the analysis used to develop the optimal input designs, and demonstrated the feasibility and practical utility of the optimal input design technique.

  3. Input filter compensation for switching regulators

    NASA Technical Reports Server (NTRS)

    Lee, F. C.

    1984-01-01

    Problems caused by input filter interaction and conventional input filter design techniques are discussed. The concept of feedforward control is modeled with an input filter and a buck regulator. Experimental measurement and comparison to the analytical predictions is carried out. Transient response and the use of a feedforward loop to stabilize the regulator system is described. Other possible applications for feedforward control are included.

  4. Textual Enhancement of Input: Issues and Possibilities

    ERIC Educational Resources Information Center

    Han, ZhaoHong; Park, Eun Sung; Combs, Charles

    2008-01-01

    The input enhancement hypothesis proposed by Sharwood Smith (1991, 1993) has stimulated considerable research over the last 15 years. This article reviews the research on textual enhancement of input (TE), an area where the majority of input enhancement studies have aggregated. Methodological idiosyncrasies are the norm of this body of research.…

  5. Input Devices for Young Handicapped Children.

    ERIC Educational Resources Information Center

    Morris, Karen

    The versatility of the computer can be expanded considerably for young handicapped children by using input devices other than the typewriter-style keyboard. Input devices appropriate for young children can be classified into four categories: alternative keyboards, contact switches, speech input devices, and cursor control devices. Described are…

  6. Visualization-by-Sketching: An Artist's Interface for Creating Multivariate Time-Varying Data Visualizations.

    PubMed

    Schroeder, David; Keefe, Daniel F

    2016-01-01

    We present Visualization-by-Sketching, a direct-manipulation user interface for designing new data visualizations. The goals are twofold: First, make the process of creating real, animated, data-driven visualizations of complex information more accessible to artists, graphic designers, and other visual experts with traditional, non-technical training. Second, support and enhance the role of human creativity in visualization design, enabling visual experimentation and workflows similar to what is possible with traditional artistic media. The approach is to conceive of visualization design as a combination of processes that are already closely linked with visual creativity: sketching, digital painting, image editing, and reacting to exemplars. Rather than studying and tweaking low-level algorithms and their parameters, designers create new visualizations by painting directly on top of a digital data canvas, sketching data glyphs, and arranging and blending together multiple layers of animated 2D graphics. This requires new algorithms and techniques to interpret painterly user input relative to data "under" the canvas, balance artistic freedom with the need to produce accurate data visualizations, and interactively explore large (e.g., terabyte-sized) multivariate datasets. Results demonstrate a variety of multivariate data visualization techniques can be rapidly recreated using the interface. More importantly, results and feedback from artists support the potential for interfaces in this style to attract new, creative users to the challenging task of designing more effective data visualizations and to help these users stay "in the creative zone" as they work. PMID:26529734

  7. Visual bioethics.

    PubMed

    Lauritzen, Paul

    2008-12-01

    Although images are pervasive in public policy debates in bioethics, few who work in the field attend carefully to the way that images function rhetorically. If the use of images is discussed at all, it is usually to dismiss appeals to images as a form of manipulation. Yet it is possible to speak meaningfully of visual arguments. Examining the appeal to images of the embryo and fetus in debates about abortion and stem cell research, I suggest that bioethicists would be well served by attending much more carefully to how images function in public policy debates. PMID:19085479

  8. A ventral visual stream reading center independent of visual experience.

    PubMed

    Reich, Lior; Szwed, Marcin; Cohen, Laurent; Amedi, Amir

    2011-03-01

    The visual word form area (VWFA) is a ventral stream visual area that develops expertise for visual reading. It is activated across writing systems and scripts and encodes letter strings irrespective of case, font, or location in the visual field with striking anatomical reproducibility across individuals. In the blind, comparable reading expertise can be achieved using Braille. This study investigated which area plays the role of the VWFA in the blind. One would expect this area to be at either parietal or bilateral occipital cortex, reflecting the tactile nature of the task and crossmodal plasticity, respectively. However, according to the metamodal theory, which suggests that brain areas are responsive to a specific representation or computation regardless of their input sensory modality, we predicted recruitment of the left-hemispheric VWFA, identically to the sighted. Using functional magnetic resonance imaging, we show that activation during Braille reading in blind individuals peaks in the VWFA, with striking anatomical consistency within and between blind and sighted. Furthermore, the VWFA is reading selective when contrasted to high-level language and low-level sensory controls. Thus, we propose that the VWFA is a metamodal reading area that develops specialization for reading regardless of visual experience. PMID:21333539

  9. Sleep physiology, abnormal States, and therapeutic interventions.

    PubMed

    Wickboldt, Alvah T; Bowen, Alex F; Kaye, Aaron J; Kaye, Adam M; Rivera Bueno, Franklin; Kaye, Alan D

    2012-01-01

    Sleep is essential. Unfortunately, a significant portion of the population experiences altered sleep states that often result in a multitude of health-related issues. The regulation of sleep and sleep-wake cycles is an area of intense research, and many options for treatment are available. The following review summarizes the current understanding of normal and abnormal sleep-related conditions and the available treatment options. All clinicians managing patients must recommend appropriate therapeutic interventions for abnormal sleep states. Clinicians' solid understanding of sleep physiology, abnormal sleep states, and treatments will greatly benefit patients regardless of their disease process. PMID:22778676

  10. Sleep Physiology, Abnormal States, and Therapeutic Interventions

    PubMed Central

    Wickboldt, Alvah T.; Bowen, Alex F.; Kaye, Aaron J.; Kaye, Adam M.; Rivera Bueno, Franklin; Kaye, Alan D.

    2012-01-01

    Sleep is essential. Unfortunately, a significant portion of the population experiences altered sleep states that often result in a multitude of health-related issues. The regulation of sleep and sleep-wake cycles is an area of intense research, and many options for treatment are available. The following review summarizes the current understanding of normal and abnormal sleep-related conditions and the available treatment options. All clinicians managing patients must recommend appropriate therapeutic interventions for abnormal sleep states. Clinicians' solid understanding of sleep physiology, abnormal sleep states, and treatments will greatly benefit patients regardless of their disease process. PMID:22778676

  11. Right Liver Lobe Hypoplasia and Related Abnormalities

    PubMed Central

    Alicioglu, Banu

    2015-01-01

    Summary Background Hypoplasia and agenesis of the liver lobe is a rare abnormality. It is associated with biliary system abnormalities, high location of the right kidney, and right colon interposition. These patients are prone to gallstones, portal hypertension and possible surgical complications because of anatomical disturbance. Case Report Magnetic resonance imaging features of a rare case of hypoplasia of the right lobe of the liver in a sigmoid cancer patient are presented. Conclusions Hypoplasia of the right liver should not be confused with liver atrophy; indeed, associations with other coexistent abnormalities are also possible. Awareness and familiarity with these anomalies are necessary to avoid fatal surgical and interventional complications. PMID:26634012

  12. Numerically abnormal chromosome constitutions in humans

    SciTech Connect

    1993-12-31

    Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

  13. Optical Coherence Tomography versus Visual Evoked Potentials in detecting subclinical visual impairment in multiple sclerosis

    PubMed Central

    Grecescu, M

    2014-01-01

    Rationale. Visual impairment is one of the most common clinical manifestations of multiple sclerosis (MS). Some multiple sclerosis patients complain of poor vision although the Snellen visual acuity is 20/20. This study reveals that sensitive measurements like visual evoked potential (VEP) and optical coherence tomography (OCT) can evidence subclinical disturbances of visual pathway. These methods examine the relation between the visual function (VEP) and retinal nerve fiber layer (RNFL) thickness, as a structural biomarker for axonal loss in patients with multiple sclerosis (MS). The findings in this study indicate the utility of combining structural and functional testing in clinical research on patients with MS. Purpose. To detect visual impairment in a population of visually asymptomatic patients affected by clinically definite multiple sclerosis (MS) and to compare the utility of optical coherence tomography (OCT) versus visual evoked potentials (VEP). Material and methods. Fourteen patients (28 eyes) affected by clinically definite MS, without a history of optic neuritis and asymptomatic for visual disturbances, were initially fully examined (visual acuity, ocular fundus, biomicroscopy) from an ophthalmic point of view and then measured by OCT (RNFL thickness) and VEP. Patients with a history of glaucoma or other retinal or optic nerve disease were excluded. Results. Of fourteen patients (28 eyes), VEP was abnormal in 11 cases (78,57%) and OCT (RNFL thickness) was abnormal in 5 cases (35,71%), while 3 patients had no abnormalities on neither tests. Conclusions. Optical coherence tomography (OCT) is less sensitive than visual evoked potentials (VEPs) in detecting visual subclinical impairment in patients with multiple sclerosis (MS). VEP remains the preferred test for the detection of clinical and subclinical optic neuritis. OCT may provide complementary information to VEP in cases with clinical definite MS and represent a valuable research instrument for the

  14. COSMIC/NASTRAN Free-field Input

    NASA Technical Reports Server (NTRS)

    Chan, G. C.

    1984-01-01

    A user's guide to the COSMIC/NASTRAN free field input for the Bulk Data section of the NASTRAN program is proposed. The free field input is designed to be user friendly and the user is not forced out of the computer system due to input errors. It is easy to use, with only a few simple rules to follow. A stand alone version of the COSMIC/NASTRAN free field input is also available. The use of free field input is illustrated by a number of examples.

  15. Combined contributions of feedforward and feedback inputs to bottom-up attention

    PubMed Central

    Khorsand, Peyman; Moore, Tirin; Soltani, Alireza

    2015-01-01

    In order to deal with a large amount of information carried by visual inputs entering the brain at any given point in time, the brain swiftly uses the same inputs to enhance processing in one part of visual field at the expense of the others. These processes, collectively called bottom-up attentional selection, are assumed to solely rely on feedforward processing of the external inputs, as it is implied by the nomenclature. Nevertheless, evidence from recent experimental and modeling studies points to the role of feedback in bottom-up attention. Here, we review behavioral and neural evidence that feedback inputs are important for the formation of signals that could guide attentional selection based on exogenous inputs. Moreover, we review results from a modeling study elucidating mechanisms underlying the emergence of these signals in successive layers of neural populations and how they depend on feedback from higher visual areas. We use these results to interpret and discuss more recent findings that can further unravel feedforward and feedback neural mechanisms underlying bottom-up attention. We argue that while it is descriptively useful to separate feedforward and feedback processes underlying bottom-up attention, these processes cannot be mechanistically separated into two successive stages as they occur at almost the same time and affect neural activity within the same brain areas using similar neural mechanisms. Therefore, understanding the interaction and integration of feedforward and feedback inputs is crucial for better understanding of bottom-up attention. PMID:25784883

  16. PREVIMER : Meteorological inputs and outputs

    NASA Astrophysics Data System (ADS)

    Ravenel, H.; Lecornu, F.; Kerléguer, L.

    2009-09-01

    PREVIMER is a pre-operational system aiming to provide a wide range of users, from private individuals to professionals, with short-term forecasts about the coastal environment along the French coastlines bordering the English Channel, the Atlantic Ocean, and the Mediterranean Sea. Observation data and digital modelling tools first provide 48-hour (probably 96-hour by summer 2009) forecasts of sea states, currents, sea water levels and temperatures. The follow-up of an increasing number of biological parameters will, in time, complete this overview of coastal environment. Working in partnership with the French Naval Hydrographic and Oceanographic Service (Service Hydrographique et Océanographique de la Marine, SHOM), the French National Weather Service (Météo-France), the French public science and technology research institute (Institut de Recherche pour le Développement, IRD), the European Institute of Marine Studies (Institut Universitaire Européen de la Mer, IUEM) and many others, IFREMER (the French public institute fo marine research) is supplying the technologies needed to ensure this pertinent information, available daily on Internet at http://www.previmer.org, and stored at the Operational Coastal Oceanographic Data Centre. Since 2006, PREVIMER publishes the results of demonstrators assigned to limited geographic areas and to specific applications. This system remains experimental. The following topics are covered : Hydrodynamic circulation, sea states, follow-up of passive tracers, conservative or non-conservative (specifically of microbiological origin), biogeochemical state, primary production. Lastly, PREVIMER provides researchers and R&D departments with modelling tools and access to the database, in which the observation data and the modelling results are stored, to undertake environmental studies on new sites. The communication will focus on meteorological inputs to and outputs from PREVIMER. It will draw the lessons from almost 3 years during

  17. Turn customer input into innovation.

    PubMed

    Ulwick, Anthony W

    2002-01-01

    It's difficult to find a company these days that doesn't strive to be customer-driven. Too bad, then, that most companies go about the process of listening to customers all wrong--so wrong, in fact, that they undermine innovation and, ultimately, the bottom line. What usually happens is this: Companies ask their customers what they want. Customers offer solutions in the form of products or services. Companies then deliver these tangibles, and customers just don't buy. The reason is simple--customers aren't expert or informed enough to come up with solutions. That's what your R&D team is for. Rather, customers should be asked only for outcomes--what they want a new product or service to do for them. The form the solutions take should be up to you, and you alone. Using Cordis Corporation as an example, this article describes, in fine detail, a series of effective steps for capturing, analyzing, and utilizing customer input. First come indepth interviews, in which a moderator works with customers to deconstruct a process or activity in order to unearth "desired outcomes." Addressing participants' comments one at a time, the moderator rephrases them to be both unambiguous and measurable. Once the interviews are complete, researchers then compile a comprehensive list of outcomes that participants rank in order of importance and degree to which they are satisfied by existing products. Finally, using a simple mathematical formula called the "opportunity calculation," researchers can learn the relative attractiveness of key opportunity areas. These data can be used to uncover opportunities for product development, to properly segment markets, and to conduct competitive analysis. PMID:12964470

  18. Scientific Visualization and Computational Science: Natural Partners

    NASA Technical Reports Server (NTRS)

    Uselton, Samuel P.; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    Scientific visualization is developing rapidly, stimulated by computational science, which is gaining acceptance as a third alternative to theory and experiment. Computational science is based on numerical simulations of mathematical models derived from theory. But each individual simulation is like a hypothetical experiment; initial conditions are specified, and the result is a record of the observed conditions. Experiments can be simulated for situations that can not really be created or controlled. Results impossible to measure can be computed.. Even for observable values, computed samples are typically much denser. Numerical simulations also extend scientific exploration where the mathematics is analytically intractable. Numerical simulations are used to study phenomena from subatomic to intergalactic scales and from abstract mathematical structures to pragmatic engineering of everyday objects. But computational science methods would be almost useless without visualization. The obvious reason is that the huge amounts of data produced require the high bandwidth of the human visual system, and interactivity adds to the power. Visualization systems also provide a single context for all the activities involved from debugging the simulations, to exploring the data, to communicating the results. Most of the presentations today have their roots in image processing, where the fundamental task is: Given an image, extract information about the scene. Visualization has developed from computer graphics, and the inverse task: Given a scene description, make an image. Visualization extends the graphics paradigm by expanding the possible input. The goal is still to produce images; the difficulty is that the input is not a scene description displayable by standard graphics methods. Visualization techniques must either transform the data into a scene description or extend graphics techniques to display this odd input. Computational science is a fertile field for visualization

  19. Unfolding Dynamic Networks for Visual Exploration.

    PubMed

    Bach, Benjamin

    2016-01-01

    Visualization builds on the human capacity to quickly process parallel visual inputs and to offload cognitive processes. Interactive visualizations can become interfaces between humans, their data, and the phenomena represented by the data. Such interfaces can allow for exploration, enable serendipitous discoveries, and serve as a mental metaphor to help us remember and reason about the data. This article gives a brief overview of the author's dissertation research, which is concerned with creating and evaluating novel interfaces to explore dynamic networks, supporting analysts in formulating hypotheses, and discussing proper analysis methods. PMID:26960029

  20. Low-set ears and pinna abnormalities

    MedlinePlus

    Low-set ears; Microtia; "Lop" ear; Pinna abnormalities; Genetic defect-pinna; Congenital defect-pinna ... The outer ear or "pinna" forms when the baby is growing in the mother's womb. The growth of this ear part ...

  1. Pinna abnormalities and low-set ears

    MedlinePlus

    ... because they do not affect hearing. However, sometimes cosmetic surgery is recommended. Skin tags may be tied off, ... 5 years old. More severe abnormalities may require surgery for cosmetic reasons as well as for function. Surgery to ...

  2. Abnormal Uterine Bleeding (Beyond the Basics)

    MedlinePlus

    ... Approach to abnormal uterine bleeding in nonpregnant reproductive-age women Differential diagnosis of genital tract bleeding in women Postmenopausal uterine bleeding The following organizations also provide reliable health information. ● National Library of Medicine ( www.nlm.nih.gov/ ...

  3. Spontaneous occurrence of chromosome abnormality in cats.

    PubMed

    THULINE, H C; NORBY, D W

    1961-08-25

    A syndrome in male cats analogous to chromatin-positive Klinefelter's syndrome in human males has been demonstrated. The physical characteristics which suggested an abnormality of chromosome number in cats were "calico" or "tortoise-shell" coat colors in a male. Buccal mucosal smears were found to have "female-type" patterns in two out of 12 such male cats screened, and these two were found to have a diploid chromosome number of 39 rather than the normal 38. Testicular biopsy performed on one revealed an abnormal pattern; no gonadal tissue was found in the other cat with an abnormal chromosome number. These findings indicate that the cat, in addition to the mouse, is available for experimental study of chromosome number abnormalities. PMID:13776765

  4. Abnormal brain scan with subacute extradural haematomas

    PubMed Central

    Morley, J. Barrie; Langford, Keith H.

    1970-01-01

    Four patients are described with proven subacute extradural haematomas, each with an abnormal cerebral scan of diagnostic assistance. A possible mechanism of production of the subacute extradural haematoma is discussed, and appears to be similar to the mechanism involved in the subacute subdural haematoma. The means by which the abnormal scan results in such cases is also examined, from which it appears that non-specific meningeal membrane inflammatory reaction surrounding the haematoma is significant. Images PMID:5478950

  5. Prevalence of asymptomatic urinary abnormalities among adolescents.

    PubMed

    Fouad, Mohamed; Boraie, Maher

    2016-05-01

    To determine the prevalence of asymptomatic urinary abnormalities in adolescents, first morning clean mid-stream urine specimens were obtained from 2500 individuals and examined by dipstick and light microscopy. Adolescents with abnormal screening results were reexamined after two weeks and those who had abnormal results twice were subjected to systemic clinical examination and further clinical and laboratory investigations. Eight hundred and three (32.1%) individuals had urinary abnormalities at the first screening, which significantly decreased to 345 (13.8%) at the second screening, (P <0.001). Hematuria was the most common urinary abnormalities detected in 245 (9.8%) adolescents who had persistent urine abnormalities; 228 (9.1%) individuals had non glomerular hematuria. The hematuria was isolated in 150 (6%) individuals, combined with leukocyturia in 83 (3.3%) individuals, and combined with proteinuria in 12 (0.5%) individuals. Leukocyturia was detected in 150 (6%) of all studied adolescents; it was isolated in 39 (1.6%) individuals and combined with proteinuria in 28 (1.1%) of them. Asymptomatic bacteriuria was detected in 23 (0.9%) of all studied adolescents; all the cases were females. Proteinuria was detected in 65 (2.6%) of all the studied adolescents; 45 (1.8%) individuals had <0.5 g/day and twenty (0.8%) individuals had 0.5-3 g/day. Asymptomatic urinary abnormalities were more common in males than females and adolescents from rural than urban areas (P <0.01) and (P <0.001), respectively. The present study found a high prevalence of asymptomatic urinary abnormalities among adolescents in our population. PMID:27215241

  6. Abnormal ferrite in hyper-eutectoid steels

    SciTech Connect

    Chairuangsri, T.; Edmonds, D.V.

    2000-04-19

    The microstructural characteristics of ultra-high carbon hyper-eutectoid Fe-C and Fe-C-Cu experimental steels have been examined after isothermal transformation in a range just beneath the eutectoid temperature. Particular attention was paid to the formation of so-called abnormal ferrite, which refers to coarse ferrite grains which can form, in hyper-eutectoid compositions, on the pro-eutectoid cementite before the pearlite reaction occurs. Thus it is confirmed that the abnormal ferrite is not a result of pearlite coarsening, but of austenite decomposition before the conditions for coupled growth of pearlite are established. The abnormal ferrite formed on both allotriomorphic and Widmanstaetten forms of pro-eutectoid cementite, and significantly, it was observed that the pro-eutectoid cementite continued to grow, despite being enclosed by the abnormal ferrite. Under certain conditions this could lead to the eventual formation of substantially reduced amounts of pearlite. Thus, a model for carbon redistribution that allows the proeutectoid cementite to thicken concurrently with the abnormal ferrite is presented. The orientation relationships between the abnormal ferrite and pro-eutectoid cementite were also determined and found to be close to those which have been reported between pearlitic ferrite and pearlitic cementite.

  7. Semantic-based crossmodal processing during visual suppression

    PubMed Central

    Cox, Dustin; Hong, Sang Wook

    2015-01-01

    To reveal the mechanisms underpinning the influence of auditory input on visual awareness, we examine, (1) whether purely semantic-based multisensory integration facilitates the access to visual awareness for familiar visual events, and (2) whether crossmodal semantic priming is the mechanism responsible for the semantic auditory influence on visual awareness. Using continuous flash suppression, we rendered dynamic and familiar visual events (e.g., a video clip of an approaching train) inaccessible to visual awareness. We manipulated the semantic auditory context of the videos by concurrently pairing them with a semantically matching soundtrack (congruent audiovisual condition), a semantically non-matching soundtrack (incongruent audiovisual condition), or with no soundtrack (neutral video-only condition). We found that participants identified the suppressed visual events significantly faster (an earlier breakup of suppression) in the congruent audiovisual condition compared to the incongruent audiovisual condition and video-only condition. However, this facilitatory influence of semantic auditory input was only observed when audiovisual stimulation co-occurred. Our results suggest that the enhanced visual processing with a semantically congruent auditory input occurs due to audiovisual crossmodal processing rather than semantic priming, which may occur even when visual information is not available to visual awareness. PMID:26082736

  8. Visualization rhetoric: framing effects in narrative visualization.

    PubMed

    Hullman, Jessica; Diakopoulos, Nicholas

    2011-12-01

    Narrative visualizations combine conventions of communicative and exploratory information visualization to convey an intended story. We demonstrate visualization rhetoric as an analytical framework for understanding how design techniques that prioritize particular interpretations in visualizations that "tell a story" can significantly affect end-user interpretation. We draw a parallel between narrative visualization interpretation and evidence from framing studies in political messaging, decision-making, and literary studies. Devices for understanding the rhetorical nature of narrative information visualizations are presented, informed by the rigorous application of concepts from critical theory, semiotics, journalism, and political theory. We draw attention to how design tactics represent additions or omissions of information at various levels-the data, visual representation, textual annotations, and interactivity-and how visualizations denote and connote phenomena with reference to unstated viewing conventions and codes. Classes of rhetorical techniques identified via a systematic analysis of recent narrative visualizations are presented, and characterized according to their rhetorical contribution to the visualization. We describe how designers and researchers can benefit from the potentially positive aspects of visualization rhetoric in designing engaging, layered narrative visualizations and how our framework can shed light on how a visualization design prioritizes specific interpretations. We identify areas where future inquiry into visualization rhetoric can improve understanding of visualization interpretation. PMID:22034342

  9. Proprioceptive versus Visual Control in Autistic Children.

    ERIC Educational Resources Information Center

    Masterton, B. A.; Biederman, G. B.

    1983-01-01

    The autistic children's presumed preference for proximal over distal sensory input was studied by requiring that "autistic," retarded, and "normal" children (7-15 years old) adapt to lateral displacement of the visual field. Only autistic Ss demonstrated transfer of adaptation to the nonadapted hand, indicating reliance on proprioception rather…

  10. Patient DF's visual brain in action: Visual feedforward control in visual form agnosia.

    PubMed

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Barat, Masihullah; Goodale, Melvyn A

    2015-05-01

    Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF's grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF's performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF's grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets. In a second condition, the haptic feedback was of a constant intermediate width while the visual target varied trial by trial. Despite this incongruent feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF's spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing. PMID:25199609

  11. Time-sharing visual and auditory tracking tasks

    NASA Technical Reports Server (NTRS)

    Tsang, Pamela S.; Vidulich, Michael A.

    1987-01-01

    An experiment is described which examined the benefits of distributing the input demands of two tracking tasks as a function of task integrality. Visual and auditory compensatory tracking tasks were utilized. Results indicate that presenting the two tracking signals in two input modalities did not improve time-sharing efficiency. This was attributed to the difficulty insensitivity phenomenon.

  12. Inferring Nonlinear Neuronal Computation Based on Physiologically Plausible Inputs

    PubMed Central

    McFarland, James M.; Cui, Yuwei; Butts, Daniel A.

    2013-01-01

    The computation represented by a sensory neuron's response to stimuli is constructed from an array of physiological processes both belonging to that neuron and inherited from its inputs. Although many of these physiological processes are known to be nonlinear, linear approximations are commonly used to describe the stimulus selectivity of sensory neurons (i.e., linear receptive fields). Here we present an approach for modeling sensory processing, termed the Nonlinear Input Model (NIM), which is based on the hypothesis that the dominant nonlinearities imposed by physiological mechanisms arise from rectification of a neuron's inputs. Incorporating such ‘upstream nonlinearities’ within the standard linear-nonlinear (LN) cascade modeling structure implicitly allows for the identification of multiple stimulus features driving a neuron's response, which become directly interpretable as either excitatory or inhibitory. Because its form is analogous to an integrate-and-fire neuron receiving excitatory and inhibitory inputs, model fitting can be guided by prior knowledge about the inputs to a given neuron, and elements of the resulting model can often result in specific physiological predictions. Furthermore, by providing an explicit probabilistic model with a relatively simple nonlinear structure, its parameters can be efficiently optimized and appropriately regularized. Parameter estimation is robust and efficient even with large numbers of model components and in the context of high-dimensional stimuli with complex statistical structure (e.g. natural stimuli). We describe detailed methods for estimating the model parameters, and illustrate the advantages of the NIM using a range of example sensory neurons in the visual and auditory systems. We thus present a modeling framework that can capture a broad range of nonlinear response functions while providing physiologically interpretable descriptions of neural computation. PMID:23874185

  13. Visual Interface for Materials Simulations

    2004-08-01

    VIMES (Visual Inteface for Materials Simulations) is a graphical user interface (GUI) for pre- and post-processing alomistic materials science calculations. The code includes tools for building and visualizing simple crystals, supercells, and surfaces, as well as tools for managing and modifying the input to Sandia materials simulations codes such as Quest (Peter Schultz, SNL 9235) and Towhee (Marcus Martin, SNL 9235). It is often useful to have a graphical interlace to construct input for materialsmore » simulations codes and to analyze the output of these programs. VIMES has been designed not only to build and visualize different materials systems, but also to allow several Sandia codes to be easier to use and analyze. Furthermore. VIMES has been designed to be reasonably easy to extend to new materials programs. We anticipate that users of Sandia materials simulations codes will use VIMCS to simplify the submission and analysis of these simulations. VIMES uses standard OpenGL graphics (as implemented in the Python programming language) to display the molecules. The algorithms used to rotate, zoom, and pan molecules are all standard applications using the OpenGL libraries. VIMES uses the Marching Cubes algorithm for isosurfacing 3D data such as molecular orbitals or electron densities around the molecules.« less

  14. Cardiac ultrasonography in structural abnormalities and arrhythmias. Recognition and treatment.

    PubMed Central

    Brook, M M; Silverman, N H; Villegas, M

    1993-01-01

    Fetal cardiac ultrasonography has become an important tool in the evaluation of fetuses at risk for cardiac anomalies. It can both guide prenatal treatment and assist the management and timing of delivery. We recommend that a fetal echocardiogram be done when there is a family history of congenital heart disease; maternal disease that may affect the fetus; a history of maternal drug use, either therapeutic or illegal; evidence of other fetal abnormalities; or evidence of fetal hydrops. The optimal timing of evaluation is 18 to 22 weeks' gestation. An entire range of structural cardiac defects can be visualized prenatally, including atrioventricular septal defect, ventricular septal defect, cardiomyopathy, ventricular outlet obstruction, and complex cardiac defects. The outcome for a fetus with a recognized abnormality is unfavourable, with less than 50% surviving the neonatal period. Fetal cardiac arrhythmias are also a common occurrence, 15% in the series described here. Premature atrial or ventricular contractions are most commonly seen and usually require no treatment. Supraventricular tachycardia can result in hydrops and require in utero treatment to prevent fetal demise. Complete heart block, particularly in association with structural heart disease, has a poor prognosis for fetal survival. Images PMID:8236970

  15. Fatal subarachnoid hemorrhage caused by Aspergillus arteritis without angiographic abnormalities.

    PubMed

    Miki, Yasuo; Tomiyama, Masahiko; Haga, Rie; Nishijima, Haruo; Suzuki, Chieko; Nishijima, Michiharu; Midorikawa, Hiroshi; Sannohe, Seiya; Kurotaki, Hidekachi; Wakabayashi, Koichi; Baba, Masayuki

    2012-10-01

    No source of bleeding is detected by angiogram in 15-20% of patients with nonaneurysmal subarachnoid hemorrhage (SAH). This negative angiographic finding might suggest a benign prognosis. We describe a case of fatal SAH caused by Aspergillus arteritis without formation of fusiform dilatation or aneurysms. A 76-year-old man with a 2-month history of progressive visual loss due to pachymeningitis around the optic nerves suffered from SAH in the bilateral sylvian fissures. Repetitive serum galactomannan assay and angiography showed no abnormality. Post mortem examination revealed marked proliferation of Aspergillus in the granulomas of the frontal base dura mater. In addition, major trunks and several branches of the bilateral middle cerebral arteries were invaded by Aspergillus hyphae, which destroyed the walls in the absence of dilatation and aneurysms. Invasive aspergillosis of the CNS often forms a mycotic aneurysm. However, four autopsy cases of nonaneurysmal SAH due to invasive aspergillosis have been reported. The present case is the second autopsy case of Aspergillus arteritis without angiographic abnormality, resulting in fatal SAH. Aggressive and continuous antifungal therapy is absolutely necessary in suspected cases of invasive aspergillosis of the CNS, even if angiography is negative and therapeutic markers of aspergillosis are normal. PMID:22239342

  16. Visual search performance by paranoid and chronic undifferentiated schizophrenics.

    PubMed

    Portnoff, L A; Yesavage, J A; Acker, M B

    1981-10-01

    Disturbances in attention are among the most frequent cognitive abnormalities in schizophrenia. Recent research has suggested that some schizophrenics have difficulty with visual tracking, which is suggestive of attentional deficits. To investigate differential visual-search performance by schizophrenics, 15 chronic undifferentiated and 15 paranoid schizophrenics were compared with 15 normals on two tests measuring visual search in a systematic and an unsystematic stimulus mode. Chronic schizophrenics showed difficulty with both kinds of visual-search tasks. In contrast, paranoids had only a deficit in the systematic visual-search task. Their ability for visual search in an unsystematized stimulus array was equivalent to that of normals. Although replication and cross-validation is needed to confirm these findings, it appears that the two tests of visual search may provide a useful ancillary method for differential diagnosis between these two types of schizophrenia. PMID:7312527

  17. Abnormal Contrast Responses in the Extrastriate Cortex of Blindsight Patients

    PubMed Central

    Rees, Geraint; Kennard, Christopher; Bridge, Holly

    2015-01-01

    When the human primary visual cortex (V1) is damaged, the dominant geniculo-striate pathway can no longer convey visual information to the occipital cortex. However, many patients with such damage retain some residual visual function that must rely on an alternative pathway directly to extrastriate occipital regions. This residual vision is most robust for moving stimuli, suggesting a role for motion area hMT+. However, residual vision also requires high-contrast stimuli, which is inconsistent with hMT+ sensitivity to contrast in which even low-contrast levels elicit near-maximal neural activation. We sought to investigate this discrepancy by measuring behavioral and neural responses to increasing contrast in patients with V1 damage. Eight patients underwent behavioral testing and functional magnetic resonance imaging to record contrast sensitivity in hMT+ of their damaged hemisphere, using Gabor stimuli with a spatial frequency of 1 cycle/°. The responses from hMT+ of the blind hemisphere were compared with hMT+ and V1 responses in the sighted hemisphere of patients and a group of age-matched controls. Unlike hMT+, neural responses in V1 tend to increase linearly with increasing contrast, likely reflecting a dominant parvocellular channel input. Across all patients, the responses in hMT+ of the blind hemisphere no longer showed early saturation but increased linearly with contrast. Given the spatiotemporal parameters used in this study and the known direct subcortical projections from the koniocellular layers of the lateral geniculate nucleus to hMT+, we propose that this altered contrast sensitivity in hMT+ could be consistent with input from the koniocellular pathway. PMID:26019336

  18. Gaze and Feet as Additional Input Modalities for Interacting with Geospatial Interfaces

    NASA Astrophysics Data System (ADS)

    Çöltekin, A.; Hempel, J.; Brychtova, A.; Giannopoulos, I.; Stellmach, S.; Dachselt, R.

    2016-06-01

    Geographic Information Systems (GIS) are complex software environments and we often work with multiple tasks and multiple displays when we work with GIS. However, user input is still limited to mouse and keyboard in most workplace settings. In this project, we demonstrate how the use of gaze and feet as additional input modalities can overcome time-consuming and annoying mode switches between frequently performed tasks. In an iterative design process, we developed gaze- and foot-based methods for zooming and panning of map visualizations. We first collected appropriate gestures in a preliminary user study with a small group of experts, and designed two interaction concepts based on their input. After the implementation, we evaluated the two concepts comparatively in another user study to identify strengths and shortcomings in both. We found that continuous foot input combined with implicit gaze input is promising for supportive tasks.

  19. Mapping Synaptic Input Fields of Neurons with Super-Resolution Imaging.

    PubMed

    Sigal, Yaron M; Speer, Colenso M; Babcock, Hazen P; Zhuang, Xiaowei

    2015-10-01

    As a basic functional unit in neural circuits, each neuron integrates input signals from hundreds to thousands of synapses. Knowledge of the synaptic input fields of individual neurons, including the identity, strength, and location of each synapse, is essential for understanding how neurons compute. Here, we developed a volumetric super-resolution reconstruction platform for large-volume imaging and automated segmentation of neurons and synapses with molecular identity information. We used this platform to map inhibitory synaptic input fields of On-Off direction-selective ganglion cells (On-Off DSGCs), which are important for computing visual motion direction in the mouse retina. The reconstructions of On-Off DSGCs showed a GABAergic, receptor subtype-specific input field for generating direction selective responses without significant glycinergic inputs for mediating monosynaptic crossover inhibition. These results demonstrate unique capabilities of this super-resolution platform for interrogating neural circuitry. PMID:26435106

  20. Visual embedding: a model for visualization.

    PubMed

    Demiralp, Çağatay; Scheidegger, Carlos E; Kindlmann, Gordon L; Laidlaw, David H; Heer, Jeffrey

    2014-01-01

    The authors propose visual embedding as a model for automatically generating and evaluating visualizations. A visual embedding is a function from data points to a space of visual primitives that measurably preserves structures in the data (domain) within the mapped perceptual space (range). The authors demonstrate its use with three examples: coloring of neural tracts, scatterplots with icons, and evaluation of alternative diffusion tensor glyphs. They discuss several techniques for generating visual-embedding functions, including probabilistic graphical models for embedding in discrete visual spaces. They also describe two complementary approaches--crowdsourcing and visual product spaces--for building visual spaces with associated perceptual--distance measures. In addition, they recommend several research directions for further developing the visual-embedding model. PMID:24808163

  1. Input filter compensation for switching regulators

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Kelkar, S. S.

    1982-01-01

    The problems caused by the interaction between the input filter, output filter, and the control loop are discussed. The input filter design is made more complicated because of the need to avoid performance degradation and also stay within the weight and loss limitations. Conventional input filter design techniques are then dicussed. The concept of pole zero cancellation is reviewed; this concept is the basis for an approach to control the peaking of the output impedance of the input filter and thus mitigate some of the problems caused by the input filter. The proposed approach for control of the peaking of the output impedance of the input filter is to use a feedforward loop working in conjunction with feedback loops, thus forming a total state control scheme. The design of the feedforward loop for a buck regulator is described. A possible implementation of the feedforward loop design is suggested.

  2. Input estimation from measured structural response

    SciTech Connect

    Harvey, Dustin; Cross, Elizabeth; Silva, Ramon A; Farrar, Charles R; Bement, Matt

    2009-01-01

    This report will focus on the estimation of unmeasured dynamic inputs to a structure given a numerical model of the structure and measured response acquired at discrete locations. While the estimation of inputs has not received as much attention historically as state estimation, there are many applications where an improved understanding of the immeasurable input to a structure is vital (e.g. validating temporally varying and spatially-varying load models for large structures such as buildings and ships). In this paper, the introduction contains a brief summary of previous input estimation studies. Next, an adjoint-based optimization method is used to estimate dynamic inputs to two experimental structures. The technique is evaluated in simulation and with experimental data both on a cantilever beam and on a three-story frame structure. The performance and limitations of the adjoint-based input estimation technique are discussed.

  3. Sensitivity to the visual field origin of natural image patches in human low-level visual cortex

    PubMed Central

    2015-01-01

    Asymmetries in the response to visual patterns in the upper and lower visual fields (above and below the centre of gaze) have been associated with ecological factors relating to the structure of typical visual environments. Here, we investigated whether the content of the upper and lower visual field representations in low-level regions of human visual cortex are specialised for visual patterns that arise from the upper and lower visual fields in natural images. We presented image patches, drawn from above or below the centre of gaze of an observer navigating a natural environment, to either the upper or lower visual fields of human participants (n = 7) while we used functional magnetic resonance imaging (fMRI) to measure the magnitude of evoked activity in the visual areas V1, V2, and V3. We found a significant interaction between the presentation location (upper or lower visual field) and the image patch source location (above or below fixation); the responses to lower visual field presentation were significantly greater for image patches sourced from below than above fixation, while the responses in the upper visual field were not significantly different for image patches sourced from above and below fixation. This finding demonstrates an association between the representation of the lower visual field in human visual cortex and the structure of the visual input that is likely to be encountered below the centre of gaze. PMID:26131378

  4. GVS - GENERAL VISUALIZATION SYSTEM

    NASA Technical Reports Server (NTRS)

    Keith, S. R.

    1994-01-01

    The primary purpose of GVS (General Visualization System) is to support scientific visualization of data output by the panel method PMARC_12 (inventory number ARC-13362) on the Silicon Graphics Iris computer. GVS allows the user to view PMARC geometries and wakes as wire frames or as light shaded objects. Additionally, geometries can be color shaded according to phenomena such as pressure coefficient or velocity. Screen objects can be interactively translated and/or rotated to permit easy viewing. Keyframe animation is also available for studying unsteady cases. The purpose of scientific visualization is to allow the investigator to gain insight into the phenomena they are examining, therefore GVS emphasizes analysis, not artistic quality. GVS uses existing IRIX 4.0 image processing tools to allow for conversion of SGI RGB files to other formats. GVS is a self-contained program which contains all the necessary interfaces to control interaction with PMARC data. This includes 1) the GVS Tool Box, which supports color histogram analysis, lighting control, rendering control, animation, and positioning, 2) GVS on-line help, which allows the user to access control elements and get information about each control simultaneously, and 3) a limited set of basic GVS data conversion filters, which allows for the display of data requiring simpler data formats. Specialized controls for handling PMARC data include animation and wakes, and visualization of off-body scan volumes. GVS is written in C-language for use on SGI Iris series computers running IRIX. It requires 28Mb of RAM for execution. Two separate hardcopy documents are available for GVS. The basic document price for ARC-13361 includes only the GVS User's Manual, which outlines major features of the program and provides a tutorial on using GVS with PMARC_12 data. Programmers interested in modifying GVS for use with data in formats other than PMARC_12 format may purchase a copy of the draft GVS 3.1 Software Maintenance

  5. Retinal representation of the elementary visual signal

    PubMed Central

    Li, Peter H.; Field, Greg D.; Greschner, Martin; Ahn, Daniel; Gunning, Deborah E.; Mathieson, Keith; Sher, Alexander; Litke, Alan M.; Chichilnisky, E.J.

    2014-01-01

    Summary The propagation of visual signals from individual cone photoreceptors through parallel neural circuits was examined in the primate retina. Targeted stimulation of individual cones was combined with simultaneous recording from multiple retinal ganglion cells of identified types. The visual signal initiated by an individual cone produced strong responses with different kinetics in three of the four numerically dominant ganglion cell types. The magnitude and kinetics of light responses in each ganglion cell varied nonlinearly with stimulus strength, but in a manner that was independent of the cone of origin after accounting for the overall input strength of each cone. Based on this property of independence, the receptive field profile of an individual ganglion cell could be well estimated from responses to stimulation of each cone individually. Together these findings provide a quantitative account of how elementary visual inputs form the ganglion cell receptive field. PMID:24411737

  6. Visual function in term infants with hypoxic-ischaemic insults: correlation with neurodevelopment at 2 years of age

    PubMed Central

    Mercuri, E.; Haataja, L.; Guzzetta, A.; Anker, S.; Cowan, F.; Rutherford, M.; Andrew, R.; Braddick, O.; Cioni, G.; Dubowitz, L.; Atkinson, J.

    1999-01-01

    AIMS—To determine if there is any association between the findings of visual assessment performed at the age of 5 months and neurodevelopmental outcome at the age of 2 years in children who have sustained hypoxic-ischaemic insults.
METHODS—Twenty nine term infants with hypoxic-ischaemic encephalopathy and/or brain lesions on neonatal magnetic resonance imaging (MRI) were prospectively evaluated. At 5 months of age all the infants had their visual function assessed using the Atkinson Battery of Child Development for Examining Functional Vision, which includes the assessments of optokinetic nystagmus (OKN), acuity, visual fields, fixation shift and phase and orientation reversal visual evoked potentials. At 2 years of age the children had a structured neurological evaluation and a Griffiths developmental assessment.
RESULTS—There was good correlation between the extent of the early detected visual impairment and both neuromotor and global development. Children with more than three out of five abnormal visual tests at 5 months of age tended to have abnormal neurological examination results and abnormal developmental quotients. Children with three or fewer abnormalities tended to have developmental quotients in the normal range; the level of their performance, however, was still related to the number of visual tests passed.
CONCLUSIONS—Individual visual tests can provide important prognostic information. While abnormal OKN and acuity were always associated with abnormal outcome, normal results on visual evoked potentials and fixation shift tended to be associated with normal outcome.

 PMID:10325784

  7. Reversible cold-induced abnormalities in myocardial perfusion and function in systemic sclerosis

    SciTech Connect

    Alexander, E.L.; Firestein, G.S.; Weiss, J.L.; Heuser, R.R.; Leitl, G.; Wagner, H.N. Jr.; Brinker, J.A.; Ciuffo, A.A.; Becker, L.C.

    1986-11-01

    The effects of peripheral cold exposure on myocardial perfusion and function were studied in 13 patients with scleroderma without clinically evident myocardial disease. Ten patients had at least one transient, cold-induced, myocardial perfusion defect visualized by thallium-201 scintigraphy, and 12 had reversible, cold-induced, segmental left ventricular hypokinesis by two-dimensional echocardiography. The 10 patients with transient perfusion defects all had anatomically corresponding ventricular wall motion abnormalities. No one in either of two control groups (9 normal volunteers and 7 patients with chest pain and normal coronary arteriograms) had cold-induced abnormalities. This study is the first to show the simultaneous occurrence of cold-induced abnormalities in myocardial perfusion and function in patients with scleroderma. The results suggest that cold exposure in such patients may elicit transient reflex coronary vasoconstriction resulting in reversible myocardial ischemia and dysfunction. Chronic recurrent episodes of coronary spasm may lead to focal myocardial fibrosis.

  8. Input apparatus for dynamic signature verification systems

    DOEpatents

    EerNisse, Errol P.; Land, Cecil E.; Snelling, Jay B.

    1978-01-01

    The disclosure relates to signature verification input apparatus comprising a writing instrument and platen containing piezoelectric transducers which generate signals in response to writing pressures.

  9. Why Teach Visual Culture?

    ERIC Educational Resources Information Center

    Passmore, Kaye

    2007-01-01

    Visual culture is a hot topic in art education right now as some teachers are dedicated to teaching it and others are adamant that it has no place in a traditional art class. Visual culture, the author asserts, can include just about anything that is visually represented. Although people often think of visual culture as contemporary visuals such…

  10. Concept of visual sensation.

    PubMed

    Bundesen, C

    1977-06-01

    A direct-realist account of visual sensation is outlined. The explanatory notion of elements in visual sensation (atomic sensations) is reinterpreted, and the suggested interpretation is formally justified by constructing a Boolean algebra for visual sensations. The related notion of sensory levels (visual field vs visual world) is discussed. PMID:887374

  11. Central Cross-Talk in Task Switching : Evidence from Manipulating Input-Output Modality Compatibility

    ERIC Educational Resources Information Center

    Stephan, Denise Nadine; Koch, Iring

    2010-01-01

    Two experiments examined the role of compatibility of input and output (I-O) modality mappings in task switching. We define I-O modality compatibility in terms of similarity of stimulus modality and modality of response-related sensory consequences. Experiment 1 included switching between 2 compatible tasks (auditory-vocal vs. visual-manual) and…

  12. Rapid Airplane Parametric Input Design (RAPID)

    NASA Technical Reports Server (NTRS)

    Smith, Robert E.

    1995-01-01

    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool

  13. Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence

    NASA Astrophysics Data System (ADS)

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-03-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet --> singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature.

  14. Abnormal magnetic field effects on electrogenerated chemiluminescence.

    PubMed

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-01-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)3(3+) … TPrA(•)] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet → singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)3(3+) … TPrA(•)] complexes in solution at room temperature. PMID:25772580

  15. Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence

    PubMed Central

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-01-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet → singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature. PMID:25772580

  16. Distributed visualization

    SciTech Connect

    Arnold, T.R.

    1991-12-31

    Within the last half decade or so, two technological evolutions have culminated in mature products of potentially great utility to computer simulation. One is the emergence of low-cost workstations with versatile graphics and substantial local CPU power. The other is the adoption of UNIX as a de facto ``standard`` operating system on at least some machines offered by virtually all vendors. It is now possible to perform transient simulations in which the number- crunching capability of a supercomputer is harnessed to allow both process control and graphical visualization on a workstation. Such a distributed computer system is described as it now exists: a large FORTRAN application on a CRAY communicates with the balance of the simulation on a SUN-3 or SUN-4 via remote procedure call (RPC) protocol. The hooks to the application and the graphics have been made very flexible. Piping of output from the CRAY to the SUN is nonselective, allowing the user to summon data and draw or plot at will. The ensemble of control, application, data handling, and graphics modules is loosely coupled, which further generalizes the utility of the software design.

  17. Distributed visualization

    SciTech Connect

    Arnold, T.R.

    1991-01-01

    Within the last half decade or so, two technological evolutions have culminated in mature products of potentially great utility to computer simulation. One is the emergence of low-cost workstations with versatile graphics and substantial local CPU power. The other is the adoption of UNIX as a de facto standard'' operating system on at least some machines offered by virtually all vendors. It is now possible to perform transient simulations in which the number- crunching capability of a supercomputer is harnessed to allow both process control and graphical visualization on a workstation. Such a distributed computer system is described as it now exists: a large FORTRAN application on a CRAY communicates with the balance of the simulation on a SUN-3 or SUN-4 via remote procedure call (RPC) protocol. The hooks to the application and the graphics have been made very flexible. Piping of output from the CRAY to the SUN is nonselective, allowing the user to summon data and draw or plot at will. The ensemble of control, application, data handling, and graphics modules is loosely coupled, which further generalizes the utility of the software design.

  18. Alignment of multimodal sensory input in the superior colliculus through a gradient-matching mechanism

    PubMed Central

    Phan, An; Yamada, Jena; Feldheim, David A.

    2012-01-01

    The superior colliculus (SC) is a midbrain structure that integrates visual, somatosensory and auditory inputs to direct head and eye movements. Each of these modalities is topographically mapped and aligned with the others to ensure precise behavioral responses to multimodal stimuli. While it is clear that neural activity is instructive for topographic alignment of inputs from the visual cortex (V1) and auditory system with retinal axons in the SC, there is also evidence that activity-independent mechanisms are used to establish topographic alignment between modalities. Here, we show that the topography of the projection from primary somatosensory cortex (S1) to the SC is established during the first postnatal week. Unlike V1-SC projections, the S1-SC projection does not bifurcate when confronted with a duplicated retinocollicular map, showing that retinal input in the SC does not influence the topography of the S1-SC projection. However, S1-SC topography is disrupted in mice lacking ephrins-As, which we find are expressed in graded patterns along with their binding partners, the EphA4 and EphA7, in both S1 and the somatosensory recipient layer of the SC. Taken together, these data support a model in which somatosensory inputs into the SC map topographically and establish alignment with visual inputs in the SC using a gradient-matching mechanism. PMID:22496572

  19. Network Mechanisms Generating Abnormal and Normal Hippocampal High-Frequency Oscillations: A Computational Analysis1,2,3

    PubMed Central

    Gliske, Stephen; Catoni, Nicholas

    2015-01-01

    Abstract High-frequency oscillations (HFOs) are an intriguing potential biomarker for epilepsy, typically categorized according to peak frequency as either ripples (100–250 Hz) or fast ripples (>250 Hz). In the hippocampus, fast ripples were originally thought to be more specific to epileptic tissue, but it is still very difficult to distinguish which HFOs are caused by normal versus pathological brain activity. In this study, we use a computational model of hippocampus to investigate possible network mechanisms underpinning normal ripples, pathological ripples, and fast ripples. Our results unify several prior findings regarding HFO mechanisms, and also make several new predictions regarding abnormal HFOs. We show that HFOs are generic, emergent phenomena whose characteristics reflect a wide range of connectivity and network input. Although produced by different mechanisms, both normal and abnormal HFOs generate similar ripple frequencies, underscoring that peak frequency is unable to distinguish the two. Abnormal ripples are generic phenomena that arise when input to pyramidal cells overcomes network inhibition, resulting in high-frequency, uncoordinated firing. In addition, fast ripples transiently and sporadically arise from the precise conditions that produce abnormal ripples. Lastly, we show that such abnormal conditions do not require any specific network structure to produce coherent HFOs, as even completely asynchronous activity is capable of producing abnormal ripples and fast ripples in this manner. These results provide a generic, network-based explanation for the link between pathological ripples and fast ripples, and a unifying description for the entire spectrum from normal ripples to pathological fast ripples. PMID:26146658

  20. Abnormal head position in infantile nystagmus syndrome.

    PubMed

    Noval, Susana; González-Manrique, Mar; Rodríguez-Del Valle, José María; Rodríguez-Sánchez, José María

    2011-01-01

    Infantile nystagmus is an involuntary, bilateral, conjugate, and rhythmic oscillation of the eyes which is present at birth or develops within the first 6 months of life. It may be pendular or jerk-like and, its intensity usually increases in lateral gaze, decreasing with convergence. Up to 64% of all patients with nystagmus also present strabismus, and even more patients have an abnormal head position. The abnormal head positions are more often horizontal, but they may also be vertical or take the form of a tilt, even though the nystagmus itself is horizontal. The aim of this article is to review available information about the origin and treatment of the abnormal head position associated to nystagmus, and to describe our treatment strategies. PMID:24533187

  1. Abnormal Grain Growth Suppression in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Hales, Stephen J. (Inventor); Claytor, Harold Dale (Inventor); Alexa, Joel A. (Inventor)

    2015-01-01

    The present invention provides a process for suppressing abnormal grain growth in friction stir welded aluminum alloys by inserting an intermediate annealing treatment ("IAT") after the welding step on the article. The IAT may be followed by a solution heat treatment (SHT) on the article under effectively high solution heat treatment conditions. In at least some embodiments, a deformation step is conducted on the article under effective spin-forming deformation conditions or under effective superplastic deformation conditions. The invention further provides a welded article having suppressed abnormal grain growth, prepared by the process above. Preferably the article is characterized with greater than about 90% reduction in area fraction abnormal grain growth in any friction-stir-welded nugget.

  2. [Nutritional abnormalities in chronic obstructive pulmonary disease].

    PubMed

    Gea, Joaquim; Martínez-Llorens, Juana; Barreiro, Esther

    2014-07-22

    Nutritional abnormalities are associated with chronic obstructive pulmonary disease with a frequency ranging from 2 to 50%, depending on the geographical area and the study design. Diagnostic tools include anthropometry, bioelectrical impedance, dual energy radioabsortiometry and deuterium dilution, being the body mass and the lean mass indices the most frequently used parameters. While the most important consequences of nutritional abnormalities are muscle dysfunction and exercise limitation, factors implicated include an imbalance between caloric intake and consumption, and between anabolic and catabolic hormones, inflammation, tobacco smoking, poor physical activity, hypoxemia, some drugs and aging/comorbidities. The most important molecular mechanism for malnutrition associated with chronic obstructive pulmonary disease appears to be the mismatching between protein synthesis and breakdown. Among the therapeutic measures proposed for these nutritional abnormalities are improvements in lifestyle and nutritional support, although the use of anabolic drugs (such as secretagogues of the growth hormone) offers a new therapeutic strategy. PMID:24054776

  3. Echocardiographic abnormalities in the mucopolysaccharide storage diseases.

    PubMed

    Gross, D M; Williams, J C; Caprioli, C; Dominguez, B; Howell, R R

    1988-01-01

    The mucopolysaccharide storage diseases express themselves clinically with a wide variety of abnormalities, including growth and mental retardation, skeletal abnormalities, clouded corneas, nerve compression syndromes, upper airway obstruction and cardiovascular involvement, to name the most common. In most cases the cause of early death is cardiorespiratory failure secondary to cardiovascular involvement and upper airway obstruction. The findings of cardiac ultrasound examination in 29 children, adolescents and young adults are presented. In addition to the previously well-described abnormalities of the mitral and aortic valves in several types of mucopolysaccharide storage disease, we report patchy involvement in some cases, 3 instances of asymmetric septal hypertrophy not previously reported in mucopolysaccharide storage diseases, cardiac involvement in half of our patients with Sanfilippo syndrome and a lack of age-related severity of cardiac involvement even within the specific syndromes. PMID:3122547

  4. Advances in understanding paternally transmitted Chromosomal Abnormalities

    SciTech Connect

    Marchetti, F; Sloter, E; Wyrobek, A J

    2001-03-01

    Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.

  5. Cone photopigment bleaching abnormalities in diabetes.

    PubMed

    Elsner, A E; Burns, S A; Lobes, L A; Doft, B H

    1987-04-01

    We have used a color-matching technique to obtain estimates of the optical density of cone photopigments as a function of retinal illuminance in patients with insulin-dependent diabetes mellitus (IDDM). We found that the half-bleach illuminance of some patients is abnormally high. That is, it takes more light to bleach an equivalent amount of photopigment in these patients. Since low illuminance color matches for these patients are normal, this implies that these patients have normal amounts of photopigment, but the photopigment is not bleaching normally. This result clearly points to abnormalities in the outer retina of these diabetic patients. The most likely causes of this abnormality are either decreases in the ability of the cones to absorb light, or an increased rate of regeneration of the cone photopigments. PMID:3557875

  6. Schizophrenia and abnormal brain network hubs

    PubMed Central

    Rubinov, Mikail; Bullmore, Ed.

    2013-01-01

    Schizophrenia is a heterogeneous psychiatric disorder of unknown cause or characteristic pathology. Clinical neuroscientists increasingly postulate that schizophrenia is a disorder of brain network organization. In this article we discuss the conceptual framework of this dysconnection hypothesis, describe the predominant methodological paradigm for testing this hypothesis, and review recent evidence for disruption of central/hub brain regions, as a promising example of this hypothesis. We summarize studies of brain hubs in large-scale structural and functional brain networks and find strong evidence for network abnormalities of prefrontal hubs, and moderate evidence for network abnormalities of limbic, temporal, and parietal hubs. Future studies are needed to differentiate network dysfunction from previously observed gray- and white-matter abnormalities of these hubs, and to link endogenous network dysfunction phenotypes with perceptual, behavioral, and cognitive clinical phenotypes of schizophrenia. PMID:24174905

  7. EDP Applications to Musical Bibliography: Input Considerations

    ERIC Educational Resources Information Center

    Robbins, Donald C.

    1972-01-01

    The application of Electronic Data Processing (EDP) has been a boon in the analysis and bibliographic control of music. However, an extra step of encoding must be undertaken for input of music. The best hope to facilitate musical input is the development of an Optical Character Recognition (OCR) music-reading machine. (29 references) (Author/NH)

  8. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Stakeholder input. 3430.607 Section 3430.607 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or via Web site), as well as through a notice in the Federal Register, from the...

  9. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Stakeholder input. 3430.907 Section 3430.907 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND..., requests for input and/or Web site), as well as through a notice in the Federal Register, from...

  10. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Stakeholder input. 3430.907 Section 3430.907 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or Web site), as well as through a notice in the Federal Register, from the following...

  11. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Stakeholder input. 3430.907 Section 3430.907 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or Web site), as well as through a notice in the Federal Register, from the following...

  12. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Stakeholder input. 3430.607 Section 3430.607 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or via Web site), as well as through a notice in the Federal Register, from the...

  13. 7 CFR 3430.907 - Stakeholder input.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Stakeholder input. 3430.907 Section 3430.907 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or Web site), as well as through a notice in the Federal Register, from the following...

  14. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Stakeholder input. 3430.607 Section 3430.607 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or via Web site), as well as through a notice in the Federal Register, from the...

  15. 7 CFR 3430.607 - Stakeholder input.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Stakeholder input. 3430.607 Section 3430.607 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... input and/or via Web site), as well as through a notice in the Federal Register, from the...

  16. Computing Functions by Approximating the Input

    ERIC Educational Resources Information Center

    Goldberg, Mayer

    2012-01-01

    In computing real-valued functions, it is ordinarily assumed that the input to the function is known, and it is the output that we need to approximate. In this work, we take the opposite approach: we show how to compute the values of some transcendental functions by approximating the input to these functions, and obtaining exact answers for their…

  17. Managing Input during Assistive Technology Product Design

    ERIC Educational Resources Information Center

    Choi, Young Mi

    2011-01-01

    Many different sources of input are available to assistive technology innovators during the course of designing products. However, there is little information on which ones may be most effective or how they may be efficiently utilized within the design process. The aim of this project was to compare how three types of input--from simulation tools,…

  18. 39 CFR 3020.92 - Public input.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Public input. 3020.92 Section 3020.92 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PRODUCT LISTS Requests Initiated by the Postal Service to Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish...

  19. Abnormal carbene-silicon halide complexes.

    PubMed

    Wang, Yuzhong; Xie, Yaoming; Wei, Pingrong; Schaefer, Henry F; Robinson, Gregory H

    2016-04-14

    Reaction of the anionic N-heterocyclic dicarbene (NHDC), [:C{[N(2,6-Pr(i)2C6H3)]2CHCLi}]n (1), with SiCl4 gives the trichlorosilyl-substituted (at the C4 carbon) N-heterocyclic carbene complex (7). Abnormal carbene-SiCl4 complex (8) may be conveniently synthesized by combining 7 with HCl·NEt3. In addition, 7 may react with CH2Cl2 in warm hexane, giving the abnormal carbene-complexed SiCl3(+) cation (9). The nature of the bonding in 9 was probed with complementary DFT computations. PMID:26605692

  20. Hemorheological abnormalities in human arterial hypertension

    NASA Astrophysics Data System (ADS)

    Lo Presti, Rosalia; Hopps, Eugenia; Caimi, Gregorio

    2014-05-01

    Blood rheology is impaired in hypertensive patients. The alteration involves blood and plasma viscosity, and the erythrocyte behaviour is often abnormal. The hemorheological pattern appears to be related to some pathophysiological mechanisms of hypertension and to organ damage, in particular left ventricular hypertrophy and myocardial ischemia. Abnormalities have been observed in erythrocyte membrane fluidity, explored by fluorescence spectroscopy and electron spin resonance. This may be relevant for red cell flow in microvessels and oxygen delivery to tissues. Although blood viscosity is not a direct target of antihypertensive therapy, the rheological properties of blood play a role in the pathophysiology of arterial hypertension and its vascular complications.

  1. Ocular motor abnormalities in neurodegenerative disorders

    PubMed Central

    Antoniades, C A; Kennard, C

    2015-01-01

    Eye movements are a source of valuable information to both clinicians and scientists as abnormalities of them frequently act as clues to the localization of a disease process. Classically, they are divided into two main types: those that hold the gaze, keeping images steady on the retina (vestibulo-ocular and optokinetic reflexes) and those that shift gaze and redirect the line of sight to a new object of interest (saccades, vergence, and smooth pursuit). Here we will review some of the major ocular motor abnormalities present in neurodegenerative disorders. PMID:25412716

  2. Nonpathologizing trauma interventions in abnormal psychology courses.

    PubMed

    Hoover, Stephanie M; Luchner, Andrew F; Pickett, Rachel F

    2016-01-01

    Because abnormal psychology courses presuppose a focus on pathological human functioning, nonpathologizing interventions within these classes are particularly powerful and can reach survivors, bystanders, and perpetrators. Interventions are needed to improve the social response to trauma on college campuses. By applying psychodynamic and feminist multicultural theory, instructors can deliver nonpathologizing interventions about trauma and trauma response within these classes. We recommend class-based interventions with the following aims: (a) intentionally using nonpathologizing language, (b) normalizing trauma responses, (c) subjectively defining trauma, (d) challenging secondary victimization, and (e) questioning the delineation of abnormal and normal. The recommendations promote implications for instructor self-reflection, therapy interventions, and future research. PMID:26460794

  3. Normal and abnormal human vestibular ocular function

    NASA Technical Reports Server (NTRS)

    Peterka, R. J.; Black, F. O.

    1986-01-01

    The major motivation of this research is to understand the role the vestibular system plays in sensorimotor interactions which result in spatial disorientation and motion sickness. A second goal was to explore the range of abnormality as it is reflected in quantitative measures of vestibular reflex responses. The results of a study of vestibular reflex measurements in normal subjects and preliminary results in abnormal subjects are presented in this report. Statistical methods were used to define the range of normal responses, and determine age related changes in function.

  4. Learning Visualizations by Analogy: Promoting Visual Literacy through Visualization Morphing.

    PubMed

    Ruchikachorn, Puripant; Mueller, Klaus

    2015-09-01

    We propose the concept of teaching (and learning) unfamiliar visualizations by analogy, that is, demonstrating an unfamiliar visualization method by linking it to another more familiar one, where the in-betweens are designed to bridge the gap of these two visualizations and explain the difference in a gradual manner. As opposed to a textual description, our morphing explains an unfamiliar visualization through purely visual means. We demonstrate our idea by ways of four visualization pair examples: data table and parallel coordinates, scatterplot matrix and hyperbox, linear chart and spiral chart, and hierarchical pie chart and treemap. The analogy is commutative i.e. any member of the pair can be the unfamiliar visualization. A series of studies showed that this new paradigm can be an effective teaching tool. The participants could understand the unfamiliar visualization methods in all of the four pairs either fully or at least significantly better after they observed or interacted with the transitions from the familiar counterpart. The four examples suggest how helpful visualization pairings be identified and they will hopefully inspire other visualization morphings and associated transition strategies to be identified. PMID:26357285

  5. Statistical identification of effective input variables. [SCREEN

    SciTech Connect

    Vaurio, J.K.

    1982-09-01

    A statistical sensitivity analysis procedure has been developed for ranking the input data of large computer codes in the order of sensitivity-importance. The method is economical for large codes with many input variables, since it uses a relatively small number of computer runs. No prior judgemental elimination of input variables is needed. The sceening method is based on stagewise correlation and extensive regression analysis of output values calculated with selected input value combinations. The regression process deals with multivariate nonlinear functions, and statistical tests are also available for identifying input variables that contribute to threshold effects, i.e., discontinuities in the output variables. A computer code SCREEN has been developed for implementing the screening techniques. The efficiency has been demonstrated by several examples and applied to a fast reactor safety analysis code (Venus-II). However, the methods and the coding are general and not limited to such applications.

  6. The locus of flicker adaptation in the migraine visual system: A dichoptic study

    PubMed Central

    Thabet, Michel; Wilkinson, Frances; Wilson, Hugh R.; Karanovic, Olivera

    2014-01-01

    Background Flickering light has been shown to sensitize the migraine visual system at high stimulus contrast while elevating thresholds at low contrast. The present study employs a dichoptic psychophysical paradigm to ask whether the abnormal adaptation to flicker in migraine occurs before or after the binocular combination of inputs from the two eyes in the visual cortex. Methods Following adaptation to high contrast flicker presented to one eye only, flicker contrast increment thresholds were measured in each eye separately using dichoptic viewing. Results Modest inter-ocular transfer of adaptation was seen in both migraine and control groups at low contrast. Sensitization at high contrast in migraine relative to control participants was seen in the adapted eye only, and an unanticipated threshold elevation occurred in the non-adapted eye. Migraineurs also showed significantly lower aversion thresholds to full field flicker than control participants, but aversion scores and increment thresholds were not correlated. Conclusions The results are simulated with a three-stage neural model of adaptation that points to strong adaptation at monocular sites prior to binocular combination, and weaker adaptation at the level of cortical binocular neurons. The sensitization at high contrast in migraine is proposed to result from stronger adaptation of inhibitory neurons, which act as a monocular normalization pool. PMID:23147164

  7. VMD: visual molecular dynamics.

    PubMed

    Humphrey, W; Dalke, A; Schulten, K

    1996-02-01

    VMD is a molecular graphics program designed for the display and analysis of molecular assemblies, in particular biopolymers such as proteins and nucleic acids. VMD can simultaneously display any number of structures using a wide variety of rendering styles and coloring methods. Molecules are displayed as one or more "representations," in which each representation embodies a particular rendering method and coloring scheme for a selected subset of atoms. The atoms displayed in each representation are chosen using an extensive atom selection syntax, which includes Boolean operators and regular expressions. VMD provides a complete graphical user interface for program control, as well as a text interface using the Tcl embeddable parser to allow for complex scripts with variable substitution, control loops, and function calls. Full session logging is supported, which produces a VMD command script for later playback. High-resolution raster images of displayed molecules may be produced by generating input scripts for use by a number of photorealistic image-rendering applications. VMD has also been expressly designed with the ability to animate molecular dynamics (MD) simulation trajectories, imported either from files or from a direct connection to a running MD simulation. VMD is the visualization component of MDScope, a set of tools for interactive problem solving in structural biology, which also includes the parallel MD program NAMD, and the MDCOMM software used to connect the visualization and simulation programs. VMD is written in C++, using an object-oriented design; the program, including source code and extensive documentation, is freely available via anonymous ftp and through the World Wide Web. PMID:8744570

  8. Maturation of GABAergic Inhibition Promotes Strengthening of Temporally Coherent Inputs among Convergent Pathways

    PubMed Central

    Kuhlman, Sandra J.; Lu, Jiangteng; Lazarus, Matthew S.; Huang, Z. Josh

    2010-01-01

    Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven by converging inputs modifiable by STDP, we determined that a sufficient level of inhibition was critical to ensure that temporal coherence (correlation among presynaptic spike times) of synaptic inputs, rather than initial strength or number of inputs within a pathway, controlled postsynaptic spike timing. Inhibition exerted this effect by preferentially reducing synaptic efficacy, the ability of inputs to evoke postsynaptic action potentials, of the less coherent inputs. In visual cortical slices, inhibition potently reduced synaptic efficacy at ages during but not before the critical period of ocular dominance (OD) plasticity. Whole-cell recordings revealed that the amplitude of unitary IPSCs from parvalbumin positive (Pv+) interneurons to pyramidal neurons increased during the critical period, while the synaptic decay time-constant decreased. In addition, intrinsic properties of Pv+ interneurons matured, resulting in an increase in instantaneous firing rate. Our results suggest that maturation of inhibition in visual cortex ensures that the temporally coherent inputs (e.g. those from the open eye during monocular deprivation) control postsynaptic spike times of binocular neurons, a prerequisite for Hebbian mechanisms to induce OD plasticity. PMID:20532211

  9. Measuring Input Thresholds on an Existing Board

    NASA Technical Reports Server (NTRS)

    Kuperman, Igor; Gutrich, Daniel G.; Berkun, Andrew C.

    2011-01-01

    A critical PECL (positive emitter-coupled logic) interface to Xilinx interface needed to be changed on an existing flight board. The new Xilinx input interface used a CMOS (complementary metal-oxide semiconductor) type of input, and the driver could meet its thresholds typically, but not in worst-case, according to the data sheet. The previous interface had been based on comparison with an external reference, but the CMOS input is based on comparison with an internal divider from the power supply. A way to measure what the exact input threshold was for this device for 64 inputs on a flight board was needed. The measurement technique allowed an accurate measurement of the voltage required to switch a Xilinx input from high to low for each of the 64 lines, while only probing two of them. Directly driving an external voltage was considered too risky, and tests done on any other unit could not be used to qualify the flight board. The two lines directly probed gave an absolute voltage threshold calibration, while data collected on the remaining 62 lines without probing gave relative measurements that could be used to identify any outliers. The PECL interface was forced to a long-period square wave by driving a saturated square wave into the ADC (analog to digital converter). The active pull-down circuit was turned off, causing each line to rise rapidly and fall slowly according to the input s weak pull-down circuitry. The fall time shows up as a change in the pulse width of the signal ready by the Xilinx. This change in pulse width is a function of capacitance, pulldown current, and input threshold. Capacitance was known from the different trace lengths, plus a gate input capacitance, which is the same for all inputs. The pull-down current is the same for all inputs including the two that are probed directly. The data was combined, and the Excel solver tool was used to find input thresholds for the 62 lines. This was repeated over different supply voltages and

  10. Fine and distributed subcellular retinotopy of excitatory inputs to the dendritic tree of a collision-detecting neuron.

    PubMed

    Zhu, Ying; Gabbiani, Fabrizio

    2016-06-01

    Individual neurons in several sensory systems receive synaptic inputs organized according to subcellular topographic maps, yet the fine structure of this topographic organization and its relation to dendritic morphology have not been studied in detail. Subcellular topography is expected to play a role in dendritic integration, particularly when dendrites are extended and active. The lobula giant movement detector (LGMD) neuron in the locust visual system is known to receive topographic excitatory inputs on part of its dendritic tree. The LGMD responds preferentially to objects approaching on a collision course and is thought to implement several interesting dendritic computations. To study the fine retinotopic mapping of visual inputs onto the excitatory dendrites of the LGMD, we designed a custom microscope allowing visual stimulation at the native sampling resolution of the locust compound eye while simultaneously performing two-photon calcium imaging on excitatory dendrites. We show that the LGMD receives a distributed, fine retinotopic projection from the eye facets and that adjacent facets activate overlapping portions of the same dendritic branches. We also demonstrate that adjacent retinal inputs most likely make independent synapses on the excitatory dendrites of the LGMD. Finally, we show that the fine topographic mapping can be studied using dynamic visual stimuli. Our results reveal the detailed structure of the dendritic input originating from individual facets on the eye and their relation to that of adjacent facets. The mapping of visual space onto the LGMD's dendrites is expected to have implications for dendritic computation. PMID:27009157

  11. Sleep Disturbances among Persons Who Are Visually Impaired: Survey of Dog Guide Users.

    ERIC Educational Resources Information Center

    Fouladi, Massoud K.; Moseley, Merrick J.; Jones, Helen S.; Tobin, Michael J.

    1998-01-01

    A survey completed by 1237 adults with severe visual impairments found that 20% described the quality of their sleep as poor or very poor. Exercise was associated with better sleep and depression with poorer sleep. However, visual acuity did not predict sleep quality, casting doubt on the idea that restricted visual input (light) causes sleep…

  12. Abnormal behaviors detection using particle motion model

    NASA Astrophysics Data System (ADS)

    Chen, Yutao; Zhang, Hong; Cheng, Feiyang; Yuan, Ding; You, Yuhu

    2015-03-01

    Human abnormal behaviors detection is one of the most challenging tasks in the video surveillance for the public security control. Interaction Energy Potential model is an effective and competitive method published recently to detect abnormal behaviors, but their model of abnormal behaviors is not accurate enough, so it has some limitations. In order to solve this problem, we propose a novel Particle Motion model. Firstly, we extract the foreground to improve the accuracy of interest points detection since the complex background usually degrade the effectiveness of interest points detection largely. Secondly, we detect the interest points using the graphics features. Here, the movement of each human target can be represented by the movements of detected interest points of the target. Then, we track these interest points in videos to record their positions and velocities. In this way, the velocity angles, position angles and distance between each two points can be calculated. Finally, we proposed a Particle Motion model to calculate the eigenvalue of each frame. An adaptive threshold method is proposed to detect abnormal behaviors. Experimental results on the BEHAVE dataset and online videos show that our method could detect fight and robbery events effectively and has a promising performance.

  13. Abnormally high formation pressures, Potwar Plateau, Pakistan

    USGS Publications Warehouse

    Law, B.E.; Shah, S.H.A.; Malik, M.A.

    1998-01-01

    Abnormally high formation pressures in the Potwar Plateau of north-central Pakistan are major obstacles to oil and gas exploration. Severe drilling problems associated with high pressures have, in some cases, prevented adequate evaluation of reservoirs and significantly increased drilling costs. Previous investigations of abnormal pressure in the Potwar Plateau have only identified abnormal pressures in Neogene rocks. We have identified two distinct pressure regimes in this Himalayan foreland fold and thrust belt basin: one in Neogene rocks and another in pre-Neogene rocks. Pore pressures in Neogene rocks are as high as lithostatic and are interpreted to be due to tectonic compression and compaction disequilibrium associated with high rates of sedimentation. Pore pressure gradients in pre-Neogene rocks are generally less than those in Neogene rocks, commonly ranging from 0.5 to 0.7 psi/ft (11.3 to 15.8 kPa/m) and are most likely due to a combination of tectonic compression and hydrocarbon generation. The top of abnormally high pressure is highly variable and doesn't appear to be related to any specific lithologic seal. Consequently, attempts to predict the depth to the top of overpressure prior to drilling are precluded.

  14. Esophageal motility abnormalities in gastroesophageal reflux disease.

    PubMed

    Martinucci, Irene; de Bortoli, Nicola; Giacchino, Maria; Bodini, Giorgia; Marabotto, Elisa; Marchi, Santino; Savarino, Vincenzo; Savarino, Edoardo

    2014-05-01

    Esophageal motility abnormalities are among the main factors implicated in the pathogenesis of gastroesophageal reflux disease. The recent introduction in clinical and research practice of novel esophageal testing has markedly improved our understanding of the mechanisms contributing to the development of gastroesophageal reflux disease, allowing a better management of patients with this disorder. In this context, the present article intends to provide an overview of the current literature about esophageal motility dysfunctions in patients with gastroesophageal reflux disease. Esophageal manometry, by recording intraluminal pressure, represents the gold standard to diagnose esophageal motility abnormalities. In particular, using novel techniques, such as high resolution manometry with or without concurrent intraluminal impedance monitoring, transient lower esophageal sphincter (LES) relaxations, hypotensive LES, ineffective esophageal peristalsis and bolus transit abnormalities have been better defined and strongly implicated in gastroesophageal reflux disease development. Overall, recent findings suggest that esophageal motility abnormalities are increasingly prevalent with increasing severity of reflux disease, from non-erosive reflux disease to erosive reflux disease and Barrett's esophagus. Characterizing esophageal dysmotility among different subgroups of patients with reflux disease may represent a fundamental approach to properly diagnose these patients and, thus, to set up the best therapeutic management. Currently, surgery represents the only reliable way to restore the esophagogastric junction integrity and to reduce transient LES relaxations that are considered to be the predominant mechanism by which gastric contents can enter the esophagus. On that ground, more in depth future studies assessing the pathogenetic role of dysmotility in patients with reflux disease are warranted. PMID:24868489

  15. Pancreatic abnormalities and AIDS related sclerosing cholangitis.

    PubMed Central

    Teare, J P; Daly, C A; Rodgers, C; Padley, S P; Coker, R J; Main, J; Harris, J R; Scullion, D; Bray, G P; Summerfield, J A

    1997-01-01

    OBJECTIVES: Biliary tract abnormalities are well recognised in AIDS, most frequently related to opportunistic infection with Cryptosporidium, Microsporidium, and cytomegalovirus. We noted a high frequency of pancreatic abnormalities associated with biliary tract disease. To define these further we reviewed the clinical and radiological features in these patients. METHODS: Notes and radiographs were available from two centres for 83 HIV positive patients who had undergone endoscopic retrograde cholangiopancreatography for the investigation of cholestatic liver function tests or abdominal pain. RESULTS: 56 patients had AIDS related sclerosing cholangitis (ARSC); 86% of these patients had epigastric or right upper quadrant pain and 52% had hepatomegaly. Of the patients with ARSC, 10 had papillary stenosis alone, 11 had intra- and extrahepatic sclerosing cholangitis alone, and 35 had a combination of the two. Ampullary biopsies performed in 24 patients confirmed an opportunistic infection in 16. In 15 patients, intraluminal polyps were noted on the cholangiogram. Pancreatograms were available in 34 of the 45 patients with papillary stenosis, in which 29 (81%) had associated pancreatic duct dilatation, often with associated features of chronic pancreatitis. In the remaining 27 patients, final diagnoses included drug induced liver disease, acalculous cholecystitis, gall bladder empyema, chronic B virus hepatitis, and alcoholic liver disease. CONCLUSION: Pancreatic abnormalities are commonly seen with ARSC and may be responsible for some of the pain not relieved by biliary sphincterotomy. The most frequent radiographic biliary abnormality is papillary stenosis combined with ductal sclerosis. Images PMID:9389948

  16. Teaching Abnormal Psychology in a Multimedia Classroom.

    ERIC Educational Resources Information Center

    Brewster, JoAnne

    1996-01-01

    Examines the techniques used in teaching an abnormal psychology class in a multimedia environment with two computers and a variety of audiovisual equipment. Students respond anonymously to various questions via keypads mounted on their desks, then immediately view and discuss summaries of their responses. (MJP)

  17. Psychology Faculty Perceptions of Abnormal Psychology Textbooks

    ERIC Educational Resources Information Center

    Rapport, Zachary

    2011-01-01

    The problem. The purpose of the current study was to investigate the perceptions and opinions of psychology professors regarding the accuracy and inclusiveness of abnormal psychology textbooks. It sought answers from psychology professors to the following questions: (1) What are the expectations of the psychology faculty at a private university of…

  18. Schizophrenogenic Parenting in Abnormal Psychology Textbooks.

    ERIC Educational Resources Information Center

    Wahl, Otto F.

    1989-01-01

    Considers the treatment of family causation of schizophrenia in undergraduate abnormal psychology textbooks. Reviews texts published only after 1986. Points out a number of implications for psychologists which arise from the inclusion in these texts of the idea that parents cause schizophrenia, not the least of which is the potential for…

  19. Familial Precocious Fetal Abnormal Cortical Sulcation.

    PubMed

    Frassoni, Carolina; Avagliano, Laura; Inverardi, Francesca; Spaccini, Luigina; Parazzini, Cecilia; Rustico, Maria Angela; Bulfamante, Gaetano; Righini, Andrea

    2016-08-01

    The development of the human cerebral cortex is a complex and precisely programmed process by which alterations may lead to morphological and functional neurological abnormalities. We report familial cases of prenatally diagnosed abnormal brain, characterized by aberrant symmetrical mesial oversulcation of the parietooccipital lobes, in fetuses affected by abnormal skeletal features. Fetal brain anomalies were characterized by prenatal magnetic resonance imaging at 21 weeks of gestation and histologically evaluated at 22 weeks. Histological examination added relevant information showing some focal cortical areas of micropoligyria and heterotopic extension of the cortical plate into the marginal zone beneath the cortical surface. Genetic analysis of the fetuses excluded FGFR3 mutations known to be related to skeletal dysplasia and aberrant symmetrical oversulcation in other brain areas (temporal lobes). Hence, the present report suggests the existence of a class of rare syndromes of skeleton and brain development abnormality unrelated to FGFR3 mutations or related to other not described FGFR3 gene defects. Using magnetic resonance imaging, histopathology and molecular characterization we provide an example of a translational study of a rare and unreported brain congenital malformation. PMID:27177044

  20. Abnormal Web Usage Control by Proxy Strategies.

    ERIC Educational Resources Information Center

    Yu, Hsiang-Fu; Tseng, Li-Ming

    2002-01-01

    Approaches to designing a proxy server with Web usage control and to making the proxy server effective on local area networks are proposed to prevent abnormal Web access and to prioritize Web usage. A system is implemented to demonstrate the approaches. The implementation reveals that the proposed approaches are effective, such that the abnormal…

  1. Ultrasonography of gallbladder abnormalities due to schistosomiasis.

    PubMed

    Richter, Joachim; Azoulay, Daniel; Dong, Yi; Holtfreter, Martha C; Akpata, Robert; Calderaro, Julien; El-Scheich, Tarik; Breuer, Matthias; Neumayr, Andreas; Hatz, Christoph; Kircheis, Gerald; Botelho, Monica C; Dietrich, Christoph F

    2016-08-01

    After malaria, schistosomiasis remains the most important tropical parasitic disease in large parts of the world. Schistosomiasis has recently re-emerged in Southern Europe. Intestinal schistosomiasis is caused by most Schistosoma (S.) spp. pathogenic to humans and leads to chronic inflammation and fibrosis of the colon as well as to liver fibrosis. Gallbladder abnormalities usually occur in patients with advanced hepatic portal fibrosis due to Schistosoma mansoni infection. Occasionally, gallbladder abnormalities have been seen also in children and occurring without associated overt liver abnormalities.The specific S. mansoni-induced gallbladder abnormalities detectable by ultrasound include typical hyperechogenic wall thickening with external gallbladder wall protuberances. The luminal wall surface is smooth. The condition is usually clinically silent although some cases of symptomatic cholecystitis have been described. The ultrasonographic Murphy response is negative. Gallbladder contractility is impaired but sludge and calculi occur rarely. Contrary to other trematodes such as liver flukes, S. mansoni does not obstruct the biliary tract. Advanced gallbladder fibrosis is unlikely to reverse after therapy. PMID:27169865

  2. Abnormal interhemispheric connectivity in male psychopathic offenders

    PubMed Central

    Hoppenbrouwers, Sylco S.; De Jesus, Danilo R.; Sun, Yinming; Stirpe, Tania; Hofman, Dennis; McMaster, Jeff; Hughes, Ginny; Daskalakis, Zafiris J.; Schutter, Dennis J.L.G.

    2014-01-01

    Background Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. Methods We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. Results We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. Limitations The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. Conclusion To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders. PMID:23937798

  3. Craniofacial abnormalities among patients with Edwards Syndrome

    PubMed Central

    Rosa, Rafael Fabiano M.; Rosa, Rosana Cardoso M.; Lorenzen, Marina Boff; Zen, Paulo Ricardo G.; Graziadio, Carla; Paskulin, Giorgio Adriano

    2013-01-01

    OBJECTIVE To determine the frequency and types of craniofacial abnormalities observed in patients with trisomy 18 or Edwards syndrome (ES). METHODS This descriptive and retrospective study of a case series included all patients diagnosed with ES in a Clinical Genetics Service of a reference hospital in Southern Brazil from 1975 to 2008. The results of the karyotypic analysis, along with clinical data, were collected from medical records. RESULTS: The sample consisted of 50 patients, of which 66% were female. The median age at first evaluation was 14 days. Regarding the karyotypes, full trisomy of chromosome 18 was the main alteration (90%). Mosaicism was observed in 10%. The main craniofacial abnormalities were: microretrognathia (76%), abnormalities of the ear helix/dysplastic ears (70%), prominent occiput (52%), posteriorly rotated (46%) and low set ears (44%), and short palpebral fissures/blepharophimosis (46%). Other uncommon - but relevant - abnormalities included: microtia (18%), orofacial clefts (12%), preauricular tags (10%), facial palsy (4%), encephalocele (4%), absence of external auditory canal (2%) and asymmetric face (2%). One patient had an initial suspicion of oculo-auriculo-vertebral spectrum (OAVS) or Goldenhar syndrome. CONCLUSIONS: Despite the literature description of a characteristic clinical presentation for ES, craniofacial alterations may be variable among these patients. The OAVS findings in this sample are noteworthy. The association of ES with OAVS has been reported once in the literature. PMID:24142310

  4. Abnormal Cervical Cancer Screening Test Results

    MedlinePlus

    ... LEEP) —A thin wire loop that carries an electric current is used to remove abnormal areas of the ... the cervix using a thin wire loop and electric energy. Pap ... this document sets forth current information and opinions related to women’s health. The ...

  5. Dynamic Abnormal Grain Growth in Refractory Metals

    NASA Astrophysics Data System (ADS)

    Noell, Philip J.; Taleff, Eric M.

    2015-11-01

    High-temperature plastic deformation of the body-centered cubic (BCC) refractory metals Mo and Ta can initiate and propagate abnormal grains at significantly lower temperatures and faster rates than is possible by static annealing alone. This discovery reveals a new and potentially important aspect of abnormal grain growth (AGG) phenomena. The process of AGG during plastic deformation at elevated temperatures, termed dynamic abnormal grain growth (DAGG), was observed at homologous temperatures between 0.52 and 0.72 in both Mo and Ta sheet materials; these temperatures are much lower than those for previous observations of AGG in these materials during static annealing. DAGG was used to repeatedly grow single crystals several centimeters in length. Investigations to date have produced a basic understanding of the conditions that lead to DAGG and how DAGG is affected by microstructure in BCC refractory metals. The current state of understanding for DAGG is reviewed in this paper. Attention is given to the roles of temperature, plastic strain, boundary mobility and preexisting microstructure. DAGG is considered for its potential useful applications in solid-state crystal growth and its possibly detrimental role in creating undesired abnormal grains during thermomechanical processing.

  6. On (ab)normality: Einstein's fusiform gyrus.

    PubMed

    Weiner, Kevin S

    2015-03-01

    Recently, Hines (2014) wrote an evocative paper challenging findings from both histological and morphological studies of Einstein's brain. In this discussion paper, I extend Hines' theoretical point and further discuss how best to determine 'abnormal' morphology. To do so, I assess the sulcal patterning of Einstein's fusiform gyrus (FG) for the first time. The sulcal patterning of the FG was unconsidered in prior studies because the morphological features of the mid-fusiform sulcus have only been clarified recently. On the one hand, the sulcal patterning of Einstein's FG is abnormal relative to averages of 'normal' brains generated from two independent datasets (N = 39 and N = 15, respectively). On the other hand, within the 108 hemispheres used to make these average brains, it is not impossible to find FG sulcal patterns that resemble those of Einstein. Thus, concluding whether a morphological pattern is normal or abnormal heavily depends on the chosen analysis method (e.g. group average vs. individual). Such findings question the functional meaning of morphological 'abnormalities' when determined by comparing an individual to an average brain or average frequency characteristics. These observations are not only important for analyzing a rare brain such as that of Einstein, but also for comparing macroanatomical features between typical and atypical populations. PMID:25562419

  7. Behavioral abnormalities in captive nonhuman primates.

    PubMed

    Mallapur, Avanti; Choudhury, B C

    2003-01-01

    In this study, we dealt with 11 species of nonhuman primates across 10 zoos in India. We recorded behavior as instantaneous scans between 9 a.m. and 5 p.m. In the study, we segregated behaviors for analyses into abnormal, undesirable, active, and resting. The 4 types of abnormal behavior exhibited included floating limb, self-biting, self-clasping, and stereotypic pacing. In the study, we recorded 2 types of undesirable behavior: autoerotic stimulation and begging. Langurs and group-housed macaques did not exhibit undesirable behaviors. A male lion-tailed macaque and a male gibbon exhibited begging behavior. autoerotic stimulation and self-biting occurred rarely. Males exhibited higher levels of undesirable behavior than did females. Animals confiscated from touring zoos, circuses, and animal traders exhibited higher levels of abnormal behaviors than did animals reared in larger, recognized zoos. The stump-tailed macaque was the only species to exhibit floating limb, autoerotic stimulation, self-biting, and self-clasping. Our results show that rearing experience and group composition influence the proportions of abnormal behavior exhibited by nonhuman primates in captivity. The history of early social and environmental deprivation in these species of captive nonhuman primates probably is critical in the development of behavioral pathologies. Establishing this will require further research. PMID:14965782

  8. First-Trimester Detection of Surface Abnormalities

    PubMed Central

    Rousian, Melek; Koning, Anton H. J.; Bonsel, Gouke J.; Eggink, Alex J.; Cornette, Jérôme M. J.; Schoonderwaldt, Ernst M.; Husen-Ebbinge, Margreet; Teunissen, Katinka K.; van der Spek, Peter J.; Steegers, Eric A. P.; Exalto, Niek

    2014-01-01

    The aim was to determine the diagnostic performance of 3-dimensional virtual reality ultrasound (3D_VR_US) and conventional 2- and 3-dimensional ultrasound (2D/3D_US) for first-trimester detection of structural abnormalities. Forty-eight first trimester cases (gold standard available, 22 normal, 26 abnormal) were evaluated offline using both techniques by 5 experienced, blinded sonographers. In each case, we analyzed whether each organ category was correctly indicated as normal or abnormal and whether the specific diagnosis was correctly made. Sensitivity in terms of normal or abnormal was comparable for both techniques (P = .24). The general sensitivity for specific diagnoses was 62.6% using 3D_VR_US and 52.2% using 2D/3D_US (P = .075). The 3D_VR_US more often correctly diagnosed skeleton/limb malformations (36.7% vs 10%; P = .013). Mean evaluation time in 3D_VR_US was 4:24 minutes and in 2D/3D_US 2:53 minutes (P < .001). General diagnostic performance of 3D_VR_US and 2D/3D_US apparently is comparable. Malformations of skeleton and limbs are more often detected using 3D_VR_US. Evaluation time is longer in 3D_VR_US. PMID:24440996

  9. Sensory Abnormalities in Autism: A Brief Report

    ERIC Educational Resources Information Center

    Klintwall Lars; Holm, Anette; Eriksson, Mats; Carlsson, Lotta Hoglund; Olsson, Martina Barnevik; Hedvall, Asa; Gillberg, Christopher; Fernell, Elisabeth

    2011-01-01

    Sensory abnormalities were assessed in a population-based group of 208 20-54-month-old children, diagnosed with autism spectrum disorder (ASD) and referred to a specialized habilitation centre for early intervention. The children were subgrouped based upon degree of autistic symptoms and cognitive level by a research team at the centre. Parents…

  10. Saccadic Corollary Discharge Underlies Stable Visual Perception

    PubMed Central

    Berman, Rebecca A.; Joiner, Wilsaan M.; Wurtz, Robert H.

    2016-01-01

    Saccadic eye movements direct the high-resolution foveae of our retinas toward objects of interest. With each saccade, the image jumps on the retina, causing a discontinuity in visual input. Our visual perception, however, remains stable. Philosophers and scientists over centuries have proposed that visual stability depends upon an internal neuronal signal that is a copy of the neuronal signal driving the eye movement, now referred to as a corollary discharge (CD) or efference copy. In the old world monkey, such a CD circuit for saccades has been identified extending from superior colliculus through MD thalamus to frontal cortex, but there is little evidence that this circuit actually contributes to visual perception. We tested the influence of this CD circuit on visual perception by first training macaque monkeys to report their perceived eye direction, and then reversibly inactivating the CD as it passes through the thalamus. We found that the monkey's perception changed; during CD inactivation, there was a difference between where the monkey perceived its eyes to be directed and where they were actually directed. Perception and saccade were decoupled. We established that the perceived eye direction at the end of the saccade was not derived from proprioceptive input from eye muscles, and was not altered by contextual visual information. We conclude that the CD provides internal information contributing to the brain's creation of perceived visual stability. More specifically, the CD might provide the internal saccade vector used to unite separate retinal images into a stable visual scene. SIGNIFICANCE STATEMENT Visual stability is one of the most remarkable aspects of human vision. The eyes move rapidly several times per second, displacing the retinal image each time. The brain compensates for this disruption, keeping our visual perception stable. A major hypothesis explaining this stability invokes a signal within the brain, a corollary discharge, that informs

  11. The effect of visual context on manual localization of remembered targets

    NASA Technical Reports Server (NTRS)

    Barry, S. R.; Bloomberg, J. J.; Huebner, W. P.

    1997-01-01

    This paper examines the contribution of egocentric cues and visual context to manual localization of remembered targets. Subjects pointed in the dark to the remembered position of a target previously viewed without or within a structured visual scene. Without a remembered visual context, subjects pointed to within 2 degrees of the target. The presence of a visual context with cues of straight ahead enhanced pointing performance to the remembered location of central but not off-center targets. Thus, visual context provides strong visual cues of target position and the relationship of body position to target location. Without a visual context, egocentric cues provide sufficient input for accurate pointing to remembered targets.

  12. Multitask visual learning using genetic programming.

    PubMed

    Jaśkowski, Wojciech; Krawiec, Krzysztof; Wieloch, Bartosz

    2008-01-01

    We propose a multitask learning method of visual concepts within the genetic programming (GP) framework. Each GP individual is composed of several trees that process visual primitives derived from input images. Two trees solve two different visual tasks and are allowed to share knowledge with each other by commonly calling the remaining GP trees (subfunctions) included in the same individual. The performance of a particular tree is measured by its ability to reproduce the shapes contained in the training images. We apply this method to visual learning tasks of recognizing simple shapes and compare it to a reference method. The experimental verification demonstrates that such multitask learning often leads to performance improvements in one or both solved tasks, without extra computational effort. PMID:19053494

  13. NERSC 'Visualization Greenbook' Future visualization needs of the DOE computational science community hosted at NERSC

    SciTech Connect

    Hamann, Bernd; Bethel, E. Wes; Simon, Horst; Meza, Juan

    2002-11-04

    This report presents the findings and recommendations that emerged from a one-day workshop held at Lawrence Berkeley National Laboratory (LBNL) on June 5, 2002, in conjunction with the NERSC User Group (NUG) Meeting. The motivation for this workshop was to solicit direct input from the application science community on the subject of visualization. The workshop speakers and participants included computational scientists from a cross-section of disciplines that use the NERSC facility, as well as visualization researchers from across the country. We asked the workshop contributors how they currently visualize their results, and how they would like to do visualization in the future. We were especially interested in each individual's view of how visualization tools and services could be improved in order to better meet the needs of future computational science projects. The outcome of this workshop is a set of findings and recommendations that are presented in more detail later in this report, and briefly summarized here.

  14. Haptic over visual information in the distribution of visual attention after tool-use in near and far space.

    PubMed

    Park, George D; Reed, Catherine L

    2015-10-01

    Despite attentional prioritization for grasping space near the hands, tool-use appears to transfer attentional bias to the tool's end/functional part. The contributions of haptic and visual inputs to attentional distribution along a tool were investigated as a function of tool-use in near (Experiment 1) and far (Experiment 2) space. Visual attention was assessed with a 50/50, go/no-go, target discrimination task, while a tool was held next to targets appearing near the tool-occupied hand or tool-end. Target response times (RTs) and sensitivity (d-prime) were measured at target locations, before and after functional tool practice for three conditions: (1) open-tool: tool-end visible (visual + haptic inputs), (2) hidden-tool: tool-end visually obscured (haptic input only), and (3) short-tool: stick missing tool's length/end (control condition: hand occupied but no visual/haptic input). In near space, both open- and hidden-tool groups showed a tool-end, attentional bias (faster RTs toward tool-end) before practice; after practice, RTs near the hand improved. In far space, the open-tool group showed no bias before practice; after practice, target RTs near the tool-end improved. However, the hidden-tool group showed a consistent tool-end bias despite practice. Lack of short-tool group results suggested that hidden-tool group results were specific to haptic inputs. In conclusion, (1) allocation of visual attention along a tool due to tool practice differs in near and far space, and (2) visual attention is drawn toward the tool's end even when visually obscured, suggesting haptic input provides sufficient information for directing attention along the tool. PMID:26126805

  15. Effects of aging on audio-visual speech integration.

    PubMed

    Huyse, Aurélie; Leybaert, Jacqueline; Berthommier, Frédéric

    2014-10-01

    This study investigated the impact of aging on audio-visual speech integration. A syllable identification task was presented in auditory-only, visual-only, and audio-visual congruent and incongruent conditions. Visual cues were either degraded or unmodified. Stimuli were embedded in stationary noise alternating with modulated noise. Fifteen young adults and 15 older adults participated in this study. Results showed that older adults had preserved lipreading abilities when the visual input was clear but not when it was degraded. The impact of aging on audio-visual integration also depended on the quality of the visual cues. In the visual clear condition, the audio-visual gain was similar in both groups and analyses in the framework of the fuzzy-logical model of perception confirmed that older adults did not differ from younger adults in their audio-visual integration abilities. In the visual reduction condition, the audio-visual gain was reduced in the older group, but only when the noise was stationary, suggesting that older participants could compensate for the loss of lipreading abilities by using the auditory information available in the valleys of the noise. The fuzzy-logical model of perception confirmed the significant impact of aging on audio-visual integration by showing an increased weight of audition in the older group. PMID:25324091

  16. Optical input impedance of nanostrip antennas

    NASA Astrophysics Data System (ADS)

    Wang, Ivan; Du, Ya-ping

    2012-05-01

    We conduct an investigation into optical nanoantennas in the form of a strip dipole made from aluminum. With the finite-difference time domain simulation both optical input impedance and radiation efficiency of nanostrip antennas are addressed. An equivalent circuit is presented as well for the nanostrip antennas at optical resonances. The optical input resistance can be adjusted by varying the geometric parameters of antenna strips. By changing both strip area and strip length simultaneously, optical input resistance can be adjusted for matching impedance with an external feeding or loading circuit. It is found that the optical radiation efficiency does not change significantly when the size of a nanostrip antenna varies moderately.

  17. Wireless, relative-motion computer input device

    DOEpatents

    Holzrichter, John F.; Rosenbury, Erwin T.

    2004-05-18

    The present invention provides a system for controlling a computer display in a workspace using an input unit/output unit. A train of EM waves are sent out to flood the workspace. EM waves are reflected from the input unit/output unit. A relative distance moved information signal is created using the EM waves that are reflected from the input unit/output unit. Algorithms are used to convert the relative distance moved information signal to a display signal. The computer display is controlled in response to the display signal.

  18. Feedforward and Feedback Motor Control Abnormalities Implicate Cerebellar Dysfunctions in Autism Spectrum Disorder

    PubMed Central

    Mohanty, Suman; Greene, Rachel K.; Cook, Edwin H.; Vaillancourt, David E.; Sweeney, John A.

    2015-01-01

    Sensorimotor abnormalities are common in autism spectrum disorder (ASD) and among the earliest manifestations of the disorder. They have been studied far less than the social-communication and cognitive deficits that define ASD, but a mechanistic understanding of sensorimotor abnormalities in ASD may provide key insights into the neural underpinnings of the disorder. In this human study, we examined rapid, precision grip force contractions to determine whether feedforward mechanisms supporting initial motor output before sensory feedback can be processed are disrupted in ASD. Sustained force contractions also were examined to determine whether reactive adjustments to ongoing motor behavior based on visual feedback are altered. Sustained force was studied across multiple force levels and visual gains to assess motor and visuomotor mechanisms, respectively. Primary force contractions of individuals with ASD showed greater peak rate of force increases and large transient overshoots. Individuals with ASD also showed increased sustained force variability that scaled with force level and was more severe when visual gain was highly amplified or highly degraded. When sustaining a constant force level, their reactive adjustments were more periodic than controls, and they showed increased reliance on slower feedback mechanisms. Feedforward and feedback mechanism alterations each were associated with more severe social-communication impairments in ASD. These findings implicate anterior cerebellar circuits involved in feedforward motor control and posterior cerebellar circuits involved in transforming visual feedback into precise motor adjustments in ASD. PMID:25653359

  19. Abnormal White Matter Blood-Oxygen-Level-Dependent Signals in Chronic Mild Traumatic Brain Injury.

    PubMed

    Astafiev, Serguei V; Shulman, Gordon L; Metcalf, Nicholas V; Rengachary, Jennifer; MacDonald, Christine L; Harrington, Deborah L; Maruta, Jun; Shimony, Joshua S; Ghajar, Jamshid; Diwakar, Mithun; Huang, Ming-Xiong; Lee, Roland R; Corbetta, Maurizio

    2015-08-15

    Concussion, or mild traumatic brain injury (mTBI), can cause persistent behavioral symptoms and cognitive impairment, but it is unclear if this condition is associated with detectable structural or functional brain changes. At two sites, chronic mTBI human subjects with persistent post-concussive symptoms (three months to five years after injury) and age- and education-matched healthy human control subjects underwent extensive neuropsychological and visual tracking eye movement tests. At one site, patients and controls also performed the visual tracking tasks while blood-oxygen-level-dependent (BOLD) signals were measured with functional magnetic resonance imaging. Although neither neuropsychological nor visual tracking measures distinguished patients from controls at the level of individual subjects, abnormal BOLD signals were reliably detected in patients. The most consistent changes were localized in white matter regions: anterior internal capsule and superior longitudinal fasciculus. In contrast, BOLD signals were normal in cortical regions, such as the frontal eye field and intraparietal sulcus, that mediate oculomotor and attention functions necessary for visual tracking. The abnormal BOLD signals accurately differentiated chronic mTBI patients from healthy controls at the single-subject level, although they did not correlate with symptoms or neuropsychological performance. We conclude that subjects with persistent post-concussive symptoms can be identified years after their TBI using fMRI and an eye movement task despite showing normal structural MRI and DTI. PMID:25758167

  20. Frequent occurrence of new hepatobiliary abnormalities after bone marrow transplantation: results of a prospective study using scintigraphy and sonography.

    PubMed

    Jacobson, A F; Teefey, S A; Lee, S P; Hollister, M S; Higano, C A; Bianco, J A

    1993-07-01

    With hepatobiliary scintigraphy and sonography, we prospectively studied the occurrence of new hepatobiliary abnormalities in 18 patients before, and from 1 to 103 days after, bone marrow transplantation (BMT). Prior to BMT, all patients had normal hepatic uptake and visualization of the gallbladder by 60 min on scintigraphy, and no sludge, stones, or other abnormalities on sonography. After BMT, 16 patients (89%) developed new scintigraphic and/or sonographic hepatobiliary abnormalities. Fifteen patients had impaired liver uptake of mebrofenin, while 11 developed gallbladder uptake of mebrofenin, while 11 developed gallbladder sludge and/or stones, and 10 had gallbladder nonvisualization at 60 min. Nevertheless, no patient developed clinical or laboratory evidence of acute cholecystitis. New hepatobiliary abnormalities are more common during the first months post-BMT than clinically suspected, probably reflecting the combined effects of hepatotoxic chemoradiation therapy, graft-versus-host disease, and prolonged administration of parenteral alimentation. Evidence of acute cholecystitis is generally not found. PMID:8317403

  1. Snowflake Visualization

    NASA Astrophysics Data System (ADS)

    Bliven, L. F.; Kucera, P. A.; Rodriguez, P.

    2010-12-01

    NASA Snowflake Video Imagers (SVIs) enable snowflake visualization at diverse field sites. The natural variability of frozen precipitation is a complicating factor for remote sensing retrievals in high latitude regions. Particle classification is important for understanding snow/ice physics, remote sensing polarimetry, bulk radiative properties, surface emissivity, and ultimately, precipitation rates and accumulations. Yet intermittent storms, low temperatures, high winds, remote locations and complex terrain can impede us from observing falling snow in situ. SVI hardware and software have some special features. The standard camera and optics yield 8-bit gray-scale images with resolution of 0.05 x 0.1 mm, at 60 frames per second. Gray-scale images are highly desirable because they display contrast that aids particle classification. Black and white (1-bit) systems display no contrast, so there is less information to recognize particle types, which is particularly burdensome for aggregates. Data are analyzed at one-minute intervals using NASA's Precipitation Link Software that produces (a) Particle Catalogs and (b) Particle Size Distributions (PSDs). SVIs can operate nearly continuously for long periods (e.g., an entire winter season), so natural variability can be documented. Let’s summarize results from field studies this past winter and review some recent SVI enhancements. During the winter of 2009-2010, SVIs were deployed at two sites. One SVI supported weather observations during the 2010 Winter Olympics and Paralympics. It was located close to the summit (Roundhouse) of Whistler Mountain, near the town of Whistler, British Columbia, Canada. In addition, two SVIs were located at the King City Weather Radar Station (WKR) near Toronto, Ontario, Canada. Access was prohibited to the SVI on Whistler Mountain during the Olympics due to security concerns. So to meet the schedule for daily data products, we operated the SVI by remote control. We also upgraded the

  2. The simple fly larval visual system can process complex images.

    PubMed

    Justice, Elizabeth Daubert; Macedonia, Nicholas James; Hamilton, Catherine; Condron, Barry

    2012-01-01

    Animals that have simple eyes are thought to only detect crude visual detail such as light level. However, predatory insect larvae using a small number of visual inputs seem to distinguish complex image targets. Here we show that Drosophila melanogaster larvae, which have 12 photoreceptor cells per hemisphere, are attracted to distinct motions of other, tethered larvae and that this recognition requires the visual system but not the olfactory system. In addition, attraction to tethered larvae still occurs across a clear plastic barrier, does not occur significantly in the dark and attraction occurs to a computer screen movie of larval motion. By altering the artificial attractant movie, we conclude that visual recognition involves both spatial and temporal components. Our results demonstrate that a simple but experimentally tractable visual system can distinguish complex images and that processing in the relatively large central brain may compensate for the simple input. PMID:23093193

  3. Visual Sample Plan

    2007-10-25

    VSP selects the appropriate number and location of environmental samples to ensure that the results of statistical tests performed to provide input to risk decisions have the required confidence and performance. VSP Version 5.0 provides sample-size equations or algorithms needed by specific statistical tests appropriate for specific environmental sampling objectives. It also provides data quality assessment and statistical analysis functions to support evaluation of the data and determine whether the data support decisions regarding sitesmore » suspected of contamination. The easy-to-use program is highly visual and graphic. VSP runs on personal computers with Microsoft Windows operating systems (98, NT, 2000, Millennium Edition, CE, and XP) Designed primarily for project managers and users without expertise in statistics, VSP is applicable to two- and three-dimensional populations to be sampled (e.g., rooms and buildings, surface soil, a defined layer of subsurface soil, water bodies, and other similar applications) for studies of environmental quality. VSP is also applicable for designing sampling plans for assessing chem./rad/bio threat and hazard identification within rooms and buildings, and for designing geophysical surveys for UXO identification.« less

  4. HETEROSYNAPTIC REGULATION OF EXTERNAL GLOBUS PALLIDUS INPUTS TO THE SUBTHALAMIC NUCLEUS BY MOTOR CORTEX

    PubMed Central

    Chu, Hong-Yuan; Atherton, Jeremy F.; Wokosin, David; Surmeier, D. James; Bevan, Mark D.

    2014-01-01

    SUMMARY The two principal movement-suppressing pathways of the basal ganglia, the so-called hyperdirect and indirect pathways interact within the subthalamic nucleus (STN). An appropriate level and pattern of hyperdirect pathway cortical excitation and indirect pathway external globus pallidus (GPe) inhibition of the STN are critical for normal movement and greatly perturbed in Parkinson’s disease. Here, we demonstrate that motor cortical inputs to the STN heterosynaptically regulate through activation of postsynaptic NMDA receptors the number of functional GABAA receptor-mediated GPe-STN inputs. Thus, a homeostatic mechanism, intrinsic to the STN, balances cortical excitation by adjusting the strength of GPe inhibition. However, following loss of dopamine, excessive cortical activation of STN NMDA receptors triggers GPe-STN inputs to strengthen abnormally, contributing to the emergence of pathological, correlated activity. PMID:25578364

  5. Bottom-Up and Top-Down Input Augment the Variability of Cortical Neurons.

    PubMed

    Gómez-Laberge, Camille; Smolyanskaya, Alexandra; Nassi, Jonathan J; Kreiman, Gabriel; Born, Richard T

    2016-08-01

    Neurons in the cerebral cortex respond inconsistently to a repeated sensory stimulus, yet they underlie our stable sensory experiences. Although the nature of this variability is unknown, its ubiquity has encouraged the general view that each cell produces random spike patterns that noisily represent its response rate. In contrast, here we show that reversibly inactivating distant sources of either bottom-up or top-down input to cortical visual areas in the alert primate reduces both the spike train irregularity and the trial-to-trial variability of single neurons. A simple model in which a fraction of the pre-synaptic input is silenced can reproduce this reduction in variability, provided that there exist temporal correlations primarily within, but not between, excitatory and inhibitory input pools. A large component of the variability of cortical neurons may therefore arise from synchronous input produced by signals arriving from multiple sources. PMID:27427459

  6. A Role for Synaptic Input Distribution in a Dendritic Computation of Motion Direction in the Retina.

    PubMed

    Vlasits, Anna L; Morrie, Ryan D; Tran-Van-Minh, Alexandra; Bleckert, Adam; Gainer, Christian F; DiGregorio, David A; Feller, Marla B

    2016-03-16

    The starburst amacrine cell in the mouse retina presents an opportunity to examine the precise role of sensory input location on neuronal computations. Using visual receptive field mapping, glutamate uncaging, two-photon Ca(2+) imaging, and genetic labeling of putative synapses, we identify a unique arrangement of excitatory inputs and neurotransmitter release sites on starburst amacrine cell dendrites: the excitatory input distribution is skewed away from the release sites. By comparing computational simulations with Ca(2+) transients recorded near release sites, we show that this anatomical arrangement of inputs and outputs supports a dendritic mechanism for computing motion direction. Direction-selective Ca(2+) transients persist in the presence of a GABA-A receptor antagonist, though the directional tuning is reduced. These results indicate a synergistic interaction between dendritic and circuit mechanisms for generating direction selectivity in the starburst amacrine cell. PMID:26985724

  7. Visuals for Information.

    ERIC Educational Resources Information Center

    Pettersson, Rune

    This report focuses on the visual component of verbo-visual literacy, a communications concept involving the production, transmission, and perception of verbal and visual images. Five current problem areas in verbal-visual research are introduced and discussed: (1) communication (communication models, media consumption, new media, the information…

  8. Spelling: A Visual Skill.

    ERIC Educational Resources Information Center

    Hendrickson, Homer

    1988-01-01

    Spelling problems arise due to problems with form discrimination and inadequate visualization. A child's sequence of visual development involves learning motor control and coordination, with vision directing and monitoring the movements; learning visual comparison of size, shape, directionality, and solidity; developing visual memory or recall;…

  9. Scaling of global input-output networks

    NASA Astrophysics Data System (ADS)

    Liang, Sai; Qi, Zhengling; Qu, Shen; Zhu, Ji; Chiu, Anthony S. F.; Jia, Xiaoping; Xu, Ming

    2016-06-01

    Examining scaling patterns of networks can help understand how structural features relate to the behavior of the networks. Input-output networks consist of industries as nodes and inter-industrial exchanges of products as links. Previous studies consider limited measures for node strengths and link weights, and also ignore the impact of dataset choice. We consider a comprehensive set of indicators in this study that are important in economic analysis, and also examine the impact of dataset choice, by studying input-output networks in individual countries and the entire world. Results show that Burr, Log-Logistic, Log-normal, and Weibull distributions can better describe scaling patterns of global input-output networks. We also find that dataset choice has limited impacts on the observed scaling patterns. Our findings can help examine the quality of economic statistics, estimate missing data in economic statistics, and identify key nodes and links in input-output networks to support economic policymaking.

  10. Saccade abnormalities in autopsy-confirmed frontotemporal lobar degeneration and Alzheimer’s disease

    PubMed Central

    Boxer, Adam L.; Garbutt, Siobhan; Seeley, William W.; Jafari, Aria; Heuer, Hilary W.; Mirsky, Jacob; Hellmuth, Joanna; Trojanowski, John Q.; Huang, Erik; DeArmond, Steven; Neuhaus, John; Miller, Bruce L.

    2012-01-01

    Objective Deficits in the generation and control of saccades have been described in clinically-defined frontotemporal dementia (FTD) and Alzheimer’s disease (AD). Because clinical FTD syndromes can correspond to a number of different underlying neuropathologic FTD and non-FTD diagnoses, we sought to determine the saccade abnormalities associated with autopsy-defined cases of FTLD and AD. Participants and design An infrared eye tracker was used to record visually guided saccades to ten degree targets and antisaccades in 28 autopsy-confirmed FTD and 10 AD subjects, an average of 35.6 ± 10 months prior to death and 27 age-matched normal controls (NC). 12 FTD subjects had FTLD-TDP pathology, 15 had FTLD-tau pathology and one showed FTLD-FUS pathology. Receiver operating curve (ROC) statistics were used to determine diagnostic value of oculomotor variables. Neuroanatomical correlates of oculomotor abnormalities were investigated using voxel-based morphometry (VBM). Results All FTD and AD subjects were impaired relative to NC on the antisaccade task. However, only FTLD-tau and AD cases displayed reflexive visually-guided saccade abnormalities. AD cases displayed prominent increases in horizontal saccade latency that differentiated them from FTD cases. Impairments in velocity and gain were most severe in individuals with Progressive Supranuclear Palsy (PSP) but were also present in other tauopathies. Vertical and horizontal saccade velocity and gain were able to differentiate PSP cases from other patients. Vertical saccade velocity was strongly correlated with dorsal midbrain volume. Conclusion Decreased visually-guided saccade velocity and gain are suggestive of underlying tau pathology in FTD, with vertical saccade abnormalities most diagnostic of PSP. PMID:22491196

  11. Bilateral input protects the cortex from unilaterally-driven reorganization in children who are deaf.

    PubMed

    Gordon, Karen A; Wong, Daniel D E; Papsin, Blake C

    2013-05-01

    Unilateral hearing in childhood restricts input along the bilateral auditory pathways, possibly causing permanent reorganization. In this study we asked: (i) do the auditory pathways develop abnormally in children who are bilaterally deaf and hear with a unilateral cochlear implant? and (ii) can such differences be reversed by restoring input to the deprived ear? We measured multichannel electroencephalography in 34 children using cochlear implants and seven normal hearing peers. Dipole moments of activity became abnormally high in the auditory cortex contralateral to the first implant as unilateral cochlear implant use exceeded 1.5 years. This resulted in increased lateralization of activity to the auditory cortex contralateral to the stimulated ear and a decline in normal contralateral activity in response to stimulation from the newly implanted ear, corresponding to poorer speech perception. These results reflect an abnormal strengthening of pathways from the stimulated ear in consequence to the loss of contralateral activity including inhibitory processes normally involved in bilateral hearing. Although this reorganization occurred within a fairly short period (∼1.5 years of unilateral hearing), it was not reversed by long-term (3-4 years) bilateral cochlear implant stimulation. In bilateral listeners, effects of side of stimulation were assessed; children with long periods of unilateral cochlear implant use prior to bilateral implantation showed a reduction in normal dominance of contralateral input in the auditory cortex ipsilateral to the stimulated ear, further confirming an abnormal strengthening of pathways from the stimulated ear. By contrast, cortical activity in children using bilateral cochlear implants after limited or no unilateral cochlear implant exposure normally lateralized to the hemisphere contralateral to side of stimulation and retained normal contralateral dominance of auditory input in both hemispheres. Results demonstrate that the

  12. Dashboard Visualization for Diverse User Communities

    NASA Astrophysics Data System (ADS)

    Collier, A.; Marini, L.; Minsker, B.

    2008-12-01

    As environmental research begins to intersect further with public policy, a diverse community of both technical and non-technical users is becoming engaged in the process of scientific analysis. These new communities of users, broadly defined as stakeholders, necessitate scientific visualizations consisting of simplified key indicators of environmental status, with the ability to delve into the indicators more deeply if desired. In order to indicate environmental status, a component of change should be integrated, suggesting automatically updating indicators - essentially a real-time visualization. Another key component is that the information be available at-a-glance, with minimal interaction between the visualization and the stakeholder. Lastly, these visualizations need to be readily accessible to stakeholders with diverse levels of software expertise. A new dashboard visualization is introduced which aims to fulfill these requirements of this newly broadened research community. This dashboard consists of four distinct views which show real-time and historical data for an entire environmental system, coupled with methods for filtering the information for extreme values or particular locations. The dashboard accepts input based on the Really Simple Syndication (RSS) standard and standard text files. This input is generated utilizing a custom library for analysis and querying of the Consortium of Universities for the Advancement of Hydrologic Science (CUAHSI) Web services. The input generation components are automated through the use of Cyberintegrator, developed at the National Center for Supercomputing Applications (NCSA). The efficacy of this visualization is demonstrated for the WATERS Network testbed in Corpus Christi Bay, Texas, an environmental system which experiences seasonal hypoxia.

  13. Multiple-input experimental modal analysis

    NASA Technical Reports Server (NTRS)

    Allemang, R. J.; Brown, D. L.

    1985-01-01

    The development of experimental modal analysis techniques is reviewed. System and excitation assumptions are discussed. The methods examined include the forced normal mode excitation method, the frequency response function method, the damped complex exponential response method, the Ibrahim time domain approach, the polyreference approach, and mathematical input-output model methods. The current trend toward multiple input utilization in the estimation of system parameters is noted.

  14. Detection of Childhood Visual Impairment in At-Risk Groups

    ERIC Educational Resources Information Center

    Evenhuis, Heleen; van der Graaf, Gabrielle; Walinga, Margreet; Bindels-de Heus, Karen; van Genderen, Maria; Verhoeff, Marleen; Lantau, Kathleen; van der Meulen-Ennema, Helen; Meester, Nelleke; Wienen, Lien; Schalij-Delfos, Nicoline

    2007-01-01

    Children with intellectual disabilities have an increased risk of visual impairment, caused by both ocular and cerebral abnormalities, but this risk has not been quantified. The same applies to preterm children and children with cerebral palsy with a normal intelligence. Many cases probably go unidentified, because participation of these children…

  15. Input/output system for multiprocessors

    SciTech Connect

    Bernick, D.L.; Chan, K.K.; Chan, W.M.; Dan, Y.F.; Hoang, D.M.; Hussain, Z.; Iswandhi, G.I.; Korpi, J.E.; Sanner, M.W.; Zwangerman, J.A.

    1989-04-11

    A device controller is described, comprising: a first port-input/output controller coupled to a first input/output channel bus; and a second port-input/output controlled coupled to a second input/output channel bus; each of the first and second port-input/output controllers having: a first ownership latch means for granting shared ownership of the device controller to a first host processor to provide a first data path on a first I/O channel through the first port I/O controller between the first host processor and any peripheral, and at least a second ownership latch means operative independently of the first ownership latch means for granting shared ownership of the device controller to a second host processor independently of the first port input/output controller to provide a second data path on a second I/O channel through the second port I/O controller between the second host processor and any peripheral devices coupled to the device controller.

  16. Input filter compensation for switching regulators

    NASA Technical Reports Server (NTRS)

    Kelkar, S. S.; Lee, F. C.

    1983-01-01

    A novel input filter compensation scheme for a buck regulator that eliminates the interaction between the input filter output impedance and the regulator control loop is presented. The scheme is implemented using a feedforward loop that senses the input filter state variables and uses this information to modulate the duty cycle signal. The feedforward design process presented is seen to be straightforward and the feedforward easy to implement. Extensive experimental data supported by analytical results show that significant performance improvement is achieved with the use of feedforward in the following performance categories: loop stability, audiosusceptibility, output impedance and transient response. The use of feedforward results in isolating the switching regulator from its power source thus eliminating all interaction between the regulator and equipment upstream. In addition the use of feedforward removes some of the input filter design constraints and makes the input filter design process simpler thus making it possible to optimize the input filter. The concept of feedforward compensation can also be extended to other types of switching regulators.

  17. Significance of Input Correlations in Striatal Function

    PubMed Central

    Yim, Man Yi; Aertsen, Ad; Kumar, Arvind

    2011-01-01

    The striatum is the main input station of the basal ganglia and is strongly associated with motor and cognitive functions. Anatomical evidence suggests that individual striatal neurons are unlikely to share their inputs from the cortex. Using a biologically realistic large-scale network model of striatum and cortico-striatal projections, we provide a functional interpretation of the special anatomical structure of these projections. Specifically, we show that weak pairwise correlation within the pool of inputs to individual striatal neurons enhances the saliency of signal representation in the striatum. By contrast, correlations among the input pools of different striatal neurons render the signal representation less distinct from background activity. We suggest that for the network architecture of the striatum, there is a preferred cortico-striatal input configuration for optimal signal representation. It is further enhanced by the low-rate asynchronous background activity in striatum, supported by the balance between feedforward and feedback inhibitions in the striatal network. Thus, an appropriate combination of rates and correlations in the striatal input sets the stage for action selection presumably implemented in the basal ganglia. PMID:22125480

  18. Influential input classification in probabilistic multimedia models

    SciTech Connect

    Maddalena, Randy L.; McKone, Thomas E.; Hsieh, Dennis P.H.; Geng, Shu

    1999-05-01

    Monte Carlo analysis is a statistical simulation method that is often used to assess and quantify the outcome variance in complex environmental fate and effects models. Total outcome variance of these models is a function of (1) the uncertainty and/or variability associated with each model input and (2) the sensitivity of the model outcome to changes in the inputs. To propagate variance through a model using Monte Carlo techniques, each variable must be assigned a probability distribution. The validity of these distributions directly influences the accuracy and reliability of the model outcome. To efficiently allocate resources for constructing distributions one should first identify the most influential set of variables in the model. Although existing sensitivity and uncertainty analysis methods can provide a relative ranking of the importance of model inputs, they fail to identify the minimum set of stochastic inputs necessary to sufficiently characterize the outcome variance. In this paper, we describe and demonstrate a novel sensitivity/uncertainty analysis method for assessing the importance of each variable in a multimedia environmental fate model. Our analyses show that for a given scenario, a relatively small number of input variables influence the central tendency of the model and an even smaller set determines the shape of the outcome distribution. For each input, the level of influence depends on the scenario under consideration. This information is useful for developing site specific models and improving our understanding of the processes that have the greatest influence on the variance in outcomes from multimedia models.

  19. Reconstructing representations of dynamic visual objects in early visual cortex.

    PubMed

    Chong, Edmund; Familiar, Ariana M; Shim, Won Mok

    2016-02-01

    As raw sensory data are partial, our visual system extensively fills in missing details, creating enriched percepts based on incomplete bottom-up information. Despite evidence for internally generated representations at early stages of cortical processing, it is not known whether these representations include missing information of dynamically transforming objects. Long-range apparent motion (AM) provides a unique test case because objects in AM can undergo changes both in position and in features. Using fMRI and encoding methods, we found that the "intermediate" orientation of an apparently rotating grating, never presented in the retinal input but interpolated during AM, is reconstructed in population-level, feature-selective tuning responses in the region of early visual cortex (V1) that corresponds to the retinotopic location of the AM path. This neural representation is absent when AM inducers are presented simultaneously and when AM is visually imagined. Our results demonstrate dynamic filling-in in V1 for object features that are interpolated during kinetic transformations. PMID:26712004

  20. Reconstructing representations of dynamic visual objects in early visual cortex

    PubMed Central

    Chong, Edmund; Familiar, Ariana M.; Shim, Won Mok

    2016-01-01

    As raw sensory data are partial, our visual system extensively fills in missing details, creating enriched percepts based on incomplete bottom-up information. Despite evidence for internally generated representations at early stages of cortical processing, it is not known whether these representations include missing information of dynamically transforming objects. Long-range apparent motion (AM) provides a unique test case because objects in AM can undergo changes both in position and in features. Using fMRI and encoding methods, we found that the “intermediate” orientation of an apparently rotating grating, never presented in the retinal input but interpolated during AM, is reconstructed in population-level, feature-selective tuning responses in the region of early visual cortex (V1) that corresponds to the retinotopic location of the AM path. This neural representation is absent when AM inducers are presented simultaneously and when AM is visually imagined. Our results demonstrate dynamic filling-in in V1 for object features that are interpolated during kinetic transformations. PMID:26712004

  1. Beyond control panels: direct manipulation for visual analytics.

    PubMed

    Endert, Alex; Bradel, Lauren; North, Chris

    2013-01-01

    To tackle the onset of big data, visual analytics seeks to marry the human intuition of visualization with mathematical models' analytical horsepower. A critical question is, how will humans interact with and steer these complex models? Initially, users applied direct manipulation to such models the same way they applied it to simpler visualizations in the premodel era--using control panels to directly manipulate model parameters. However, opportunities are arising for direct manipulation of the model outputs, where the users' thought processes take place, rather than the inputs. This article presents this new agenda for direct manipulation for visual analytics. PMID:24808054

  2. Stereoscopic Displays And The Human Dual Visual System

    NASA Astrophysics Data System (ADS)

    Clapp, Robert E.

    1986-05-01

    There is only one real world. We "see" that world as extending into three dimensions because we look at it with two visual systems and with two eyes. We are not presented with two "pictures" of the real world, but with two separate sets of inputs into two separate systems. The analog of the eye as a camera has been a constant problem in the visualization of the "seeing" process. Overcoming the persistence of such an approach is the first requirement in developing a true stereoscopic display system. The eye is a dynamic sensing apparatus and supplies the brain with visual inputs. The brain constructs the scene we "see", and is responsible for our perceptions of the visual world. The sensory inputs from the human dual visual system (Ambient - wide FOV, Focal - detail FOV) are combined with other body senses in this perceptual process. Indeed, other body senses, in some degree, direct and control where and at what our eyes look. This process of conceptualization of the "real" world as perceived by ourselves can be related only within limits to the "real" world as perceived by others.. This paper addresses the processes by which our minds (with sensor inputs) work to form our stereoscopic perceptual concepts of the world, real or simulated, and the advantages (and problems) caused by our egocentric reduction of those data inputs. Discussion and evaluation of stereoscopic display systems compares current and future display systems.

  3. Visual examination apparatus

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Fitzgerald, J. W.; Rositano, S. A. (Inventor)

    1976-01-01

    An automated visual examination apparatus for measuring visual sensitivity and mapping blind spot location including a projection system for displaying to a patient a series of visual stimuli. A response switch enables him to indicate his reaction to the stimuli, and a recording system responsive to both the visual stimuli per se and the patient's response. The recording system thereby provides a correlated permanent record of both stimuli and response from which a substantive and readily apparent visual evaluation can be made.

  4. P300 audio-visual speller

    NASA Astrophysics Data System (ADS)

    Belitski, A.; Farquhar, J.; Desain, P.

    2011-04-01

    The Farwell and Donchin matrix speller is well known as one of the highest performing brain-computer interfaces (BCIs) currently available. However, its use of visual stimulation limits its applicability to users with normal eyesight. Alternative BCI spelling systems which rely on non-visual stimulation, e.g. auditory or tactile, tend to perform much more poorly and/or can be very difficult to use. In this paper we present a novel extension of the matrix speller, based on flipping the letter matrix, which allows us to use the same interface for visual, auditory or simultaneous visual and auditory stimuli. In this way we aim to allow users to utilize the best available input modality for their situation, that is use visual + auditory for best performance and move smoothly to purely auditory when necessary, e.g. when disease causes the user's eyesight to deteriorate. Our results on seven healthy subjects demonstrate the effectiveness of this approach, with our modified visual + auditory stimulation slightly out-performing the classic matrix speller. The purely auditory system performance was lower than for visual stimulation, but comparable to other auditory BCI systems.

  5. The effect of early visual deprivation on the neural bases of multisensory processing.

    PubMed

    Guerreiro, Maria J S; Putzar, Lisa; Röder, Brigitte

    2015-06-01

    Developmental vision is deemed to be necessary for the maturation of multisensory cortical circuits. Thus far, this has only been investigated in animal studies, which have shown that congenital visual deprivation markedly reduces the capability of neurons to integrate cross-modal inputs. The present study investigated the effect of transient congenital visual deprivation on the neural mechanisms of multisensory processing in humans. We used functional magnetic resonance imaging to compare responses of visual and auditory cortical areas to visual, auditory and audio-visual stimulation in cataract-reversal patients and normally sighted controls. The results showed that cataract-reversal patients, unlike normally sighted controls, did not exhibit multisensory integration in auditory areas. Furthermore, cataract-reversal patients, but not normally sighted controls, exhibited lower visual cortical processing within visual cortex during audio-visual stimulation than during visual stimulation. These results indicate that congenital visual deprivation affects the capability of cortical areas to integrate cross-modal inputs in humans, possibly because visual processing is suppressed during cross-modal stimulation. Arguably, the lack of vision in the first months after birth may result in a reorganization of visual cortex, including the suppression of noisy visual input from the deprived retina in order to reduce interference during auditory processing. PMID:25808371

  6. Visual Behaviors and Adaptations Associated with Cortical and Ocular Impairment in Children.

    ERIC Educational Resources Information Center

    Jan, J. E.; Groenveld, M.

    1993-01-01

    This article shows the usefulness of understanding visual behaviors in the diagnosis of various types of visual impairments that are due to ocular and cortical disorders. Behaviors discussed include nystagmus, ocular motor dyspraxia, head position, close viewing, field loss adaptations, mannerisms, photophobia, and abnormal color perception. (JDD)

  7. Factors Related to Impaired Visual Orienting Behavior in Children with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Boot, F. H.; Pel, J .J. M.; Evenhuis, H. M.; van der Steen, J.

    2012-01-01

    It is generally assumed that children with intellectual disabilities (ID) have an increased risk of impaired visual information processing due to brain damage or brain development disorder. So far little evidence has been presented to support this assumption. Abnormal visual orienting behavior is a sensitive tool to evaluate impaired visual…

  8. Investigating the Functional Integrity of the Dorsal Visual Pathway in Autism and Dyslexia

    ERIC Educational Resources Information Center

    Pellicano, Elizabeth; Gibson, Lisa Y.

    2008-01-01

    Numerous reports of elevated global motion thresholds across a variety of neurodevelopmental disorders have prompted researchers to suggest that abnormalities in global motion perception are a result of a general deficiency in the dorsal visual pathway. To test this hypothesis, we assessed the integrity of the dorsal visual pathway at lower…

  9. Ophthalmological, Cognitive, Electrophysiological and MRI Assessment of Visual Processing in Preterm Children without Major Neuromotor Impairment

    ERIC Educational Resources Information Center

    O'Reilly, Michelle; Vollmer, Brigitte; Vargha-Khadem, Faraneh; Neville, Brian; Connelly, Alan; Wyatt, John; Timms, Chris; De Haan, Michelle

    2010-01-01

    Many studies report chronic deficits in visual processing in children born preterm. We investigated whether functional abnormalities in visual processing exist in children born preterm but without major neuromotor impairment (i.e. cerebral palsy). Twelve such children (less than 33 weeks gestation or birthweight less than 1000 g) without major…

  10. Role of Visual Feedback Treatment for Defective /s/ Sounds in Patients with Cleft Palate.

    ERIC Educational Resources Information Center

    Michi, Ken-ichi; And Others

    1993-01-01

    Six patients with cleft palate were provided treatment using either visual feedback for tongue placement and frication or no visual feedback. Results indicated the feedback was especially useful in the treatment of defective /s/ sounds in the patients who exhibited abnormal posterior tongue posturing during dental or alveolar sounds. (Author/DB)

  11. A new synthesis for terrestrial nitrogen inputs

    NASA Astrophysics Data System (ADS)

    Houlton, B. Z.; Morford, S. L.

    2015-04-01

    Nitrogen (N) inputs sustain many different aspects of local soil processes, their services, and their interactions with the broader Earth system. We present a new synthesis for terrestrial N inputs that explicitly considers both rock and atmospheric sources of N. We review evidence for state-factor regulation over biological fixation, deposition, and rock-weathering inputs from local to global scales and in transient vs. steady-state landscapes. Our investigation highlights strong organism and topographic (relief) controls over all three N input pathways, with the anthropogenic factor clearly important in rising N deposition rates. In addition, the climate, parent material, and time factors are shown to influence patterns of fixation and rock-weathering inputs of N in diverse soil systems. Data reanalysis suggests that weathering of N-rich parent material could resolve several known cases of "missing N inputs" in ecosystems, and demonstrates how the inclusion of rock N sources into modern concepts can lead to a richer understanding of spatial and temporal patterns of ecosystem N availability. For example, explicit consideration of rock N inputs into classic pedogenic models (e.g., the Walker and Syers model) yields a fundamentally different expectation from the standard case: weathering of N-rich parent material could enhance N availability and facilitate terrestrial succession in developmentally young sites even in the absence of N-fixing organisms. We conclude that a state-factor framework for N complements our growing understanding multiple-source controls on phosphorus and cation availability in Earth's soil, but with significant exceptions given the lack of an N fixation analogue in all other biogeochemical cycles. Rather, non-symmetrical feedbacks among input pathways in which high N inputs via deposition or rock-weathering sources have the potential to reduce biological fixation rates mark N as fundamentally different from other nutrients. The new synthesis

  12. Chromosomal abnormalities in a psychiatric population

    SciTech Connect

    Lewis, K.E.; Lubetsky, M.J.; Wenger, S.L.; Steele, M.W.

    1995-02-27

    Over a 3.5 year period of time, 345 patients hospitalized for psychiatric problems were evaluated cytogenetically. The patient population included 76% males and 94% children with a mean age of 12 years. The criteria for testing was an undiagnosed etiology for mental retardation and/or autism. Cytogenetic studies identified 11, or 3%, with abnormal karyotypes, including 4 fragile X positive individuals (2 males, 2 females), and 8 with chromosomal aneuploidy, rearrangements, or deletions. While individuals with chromosomal abnormalities do not demonstrate specific behavioral, psychiatric, or developmental problems relative to other psychiatric patients, our results demonstrate the need for an increased awareness to order chromosomal analysis and fragile X testing in those individuals who have combinations of behavioral/psychiatric, learning, communication, or cognitive disturbance. 5 refs., 1 fig., 2 tabs.

  13. Abnormal grain growth in TD-nickel.

    NASA Technical Reports Server (NTRS)

    Petrovic, J. J.; Ebert, L. J.

    1972-01-01

    Characteristics of the coarse grain transformation occurring in TD-nickel 1 in. bar under certain conditions of deformation and annealing were examined. The transformation exhibits Avrami-type kinetics, with an activation energy of 250 kcal per mole. Characteristics of untransformed regions are like those of the as-received state. The transformed grain size increases with increasing deformation and decreasing annealing temperature. The coarse grain transformation is significantly different from primary recrystallization in pure nickel. Its characteristics cannot be rationalized in terms of primary recrystallization concepts, but may be explained in terms of an abnormal grain growth description. The coarse grain transformation in TD-nickel is abnormal grain growth rather than primary recrystallization. The analysis suggests an explanation for the effect of thermomechanical history on the deformation and annealing behavior of TD-nickel.

  14. Evaluation of abnormal liver function tests.

    PubMed

    Agrawal, Swastik; Dhiman, Radha K; Limdi, Jimmy K

    2016-04-01

    Incidentally detected abnormality in liver function tests is a common situation encountered by physicians across all disciplines. Many of these patients do not have primary liver disease as most of the commonly performed markers are not specific for the liver and are affected by myriad factors unrelated to liver disease. Also, many of these tests like liver enzyme levels do not measure the function of the liver, but are markers of liver injury, which is broadly of two types: hepatocellular and cholestatic. A combination of a careful history and clinical examination along with interpretation of pattern of liver test abnormalities can often identify type and aetiology of liver disease, allowing for a targeted investigation approach. Severity of liver injury is best assessed by composite scores like the Model for End Stage Liver Disease rather than any single parameter. In this review, we discuss the interpretation of the routinely performed liver tests along with the indications and utility of quantitative tests. PMID:26842972

  15. Esophageal motility abnormalities in gastroesophageal reflux disease

    PubMed Central

    Martinucci, Irene; de Bortoli, Nicola; Giacchino, Maria; Bodini, Giorgia; Marabotto, Elisa; Marchi, Santino; Savarino, Vincenzo; Savarino, Edoardo

    2014-01-01

    Esophageal motility abnormalities are among the main factors implicated in the pathogenesis of gastroesophageal reflux disease. The recent introduction in clinical and research practice of novel esophageal testing has markedly improved our understanding of the mechanisms contributing to the development of gastroesophageal reflux disease, allowing a better management of patients with this disorder. In this context, the present article intends to provide an overview of the current literature about esophageal motility dysfunctions in patients with gastroesophageal reflux disease. Esophageal manometry, by recording intraluminal pressure, represents the gold standard to diagnose esophageal motility abnormalities. In particular, using novel techniques, such as high resolution manometry with or without concurrent intraluminal impedance monitoring, transient lower esophageal sphincter (LES) relaxations, hypotensive LES, ineffective esophageal peristalsis and bolus transit abnormalities have been better defined and strongly implicated in gastroesophageal reflux disease development. Overall, recent findings suggest that esophageal motility abnormalities are increasingly prevalent with increasing severity of reflux disease, from non-erosive reflux disease to erosive reflux disease and Barrett’s esophagus. Characterizing esophageal dysmotility among different subgroups of patients with reflux disease may represent a fundamental approach to properly diagnose these patients and, thus, to set up the best therapeutic management. Currently, surgery represents the only reliable way to restore the esophagogastric junction integrity and to reduce transient LES relaxations that are considered to be the predominant mechanism by which gastric contents can enter the esophagus. On that ground, more in depth future studies assessing the pathogenetic role of dysmotility in patients with reflux disease are warranted. PMID:24868489

  16. [TMJ morphological changes in abnormal occlusion].

    PubMed

    Volkov, S I; Bazhenov, D V; Semkin, V A; Bogdanov, A O

    2013-01-01

    TMJ dysfunction is one of the most common diseases among all disorders of the maxillofacial region. Any abnormality in synchrony or amplitude of motion of the TMJ results in the malposition of the articular disc. Researchers and clinicians were always interested in topographic anatomy of the TMJ. There is currently no consensus on matters relating to changes in anatomical features of the TMJ by occlusal disturbances. PMID:23715443

  17. Congenital anorectal abnormalities in six dogs.

    PubMed

    Prassinos, N N; Papazoglou, L G; Adamama-Moraitou, K K; Galatos, A D; Gouletsou, P; Rallis, T S

    2003-07-19

    Congenital anorectal abnormalities were diagnosed in three male and three female dogs. One dog had anal stenosis, three had a persistent anal membrane, and the other two had an imperforate anus associated with a rectovaginal fistula. Five of the dogs were treated surgically, and four of them which were followed up for periods ranging from one to five years continued to pass faeces normally. PMID:12892267

  18. Practice and Educational Gaps in Abnormal Pigmentation.

    PubMed

    Mohammad, Tasneem F; Hamzavi, Iltefat H

    2016-07-01

    Dyschromia refers to abnormal pigmentation and is one of the most common diagnoses in dermatology. However, there are many educational and practice gaps in this area, specifically in melasma, postinflammatory hyperpigmentation, and vitiligo. This article aims to review the gold standard of care for these conditions as well as highlight common educational and practice gaps in these areas. Finally, possible solutions to these gaps are addressed. PMID:27363886

  19. CT of trauma to the abnormal kidney

    SciTech Connect

    Rhyner, P.; Federle, M.P.; Jeffrey, R.B.

    1984-04-01

    Traumatic injuries to already abnormal kidneys are difficult to assess by excretory urography and clinical evaluation. Bleeding and urinary extravasation may accompany minor trauma; conversely, underlying tumors, perirenal hemorrhage, and extravasation may be missed on urography. Computed tomography (CT) was performed in eight cases including three neoplasms, one adult polycystic disease, one simple renal cyst, two hydronephrotic kidneys, and one horseshoe kidney. CT provided specific and clinically useful information in each case that was not apparent on excretory urography.

  20. Chromosome abnormalities in chronic active hepatitis

    PubMed Central

    Stefanescu, D. T.; Moanga, M.; Teodorescu, M.; Brucher, J.

    1972-01-01

    An investigation on human peripheral blood lymphocyte chromosomes in chronic active hepatitis was carried out. A higher percentage of chromatid and chromosome lesions was recorded in all patients studied as compared with control groups—normal individuals, healthy subjects who had suffered from acute viral hepatitis, patients with alcoholic liver disease, and patients with mechanical jaundice due to cancer. The possible origin of these abnormalities is discussed. PMID:5076805

  1. Varenicline and Abnormal Sleep Related Events

    PubMed Central

    Savage, Ruth L.; Zekarias, Alem; Caduff-Janosa, Pia

    2015-01-01

    Study Objectives: To assess adverse drug reaction reports of “abnormal sleep related events” associated with varenicline, a partial agonist to the α4β2 subtype of nicotinic acetylcholine receptors on neurones, indicated for smoking cessation. Design: Twenty-seven reports of “abnormal sleep related events” often associated with abnormal dreams, nightmares, or somnambulism, which are known to be associated with varenicline use, were identified in the World Health Organisation (WHO) Global Individual Case Safety Reports Database. Original anonymous reports were obtained from the four national pharmacovigilance centers that submitted these reports and assessed for reaction description and causality. Measurements and Results: These 27 reports include 10 of aggressive activity occurring during sleep and seven of other sleep related harmful or potentially harmful activities, such as apparently deliberate self-harm, moving a child or a car, or lighting a stove or a cigarette. Assessment of these 17 reports of aggression or other actual or potential harm showed that nine patients recovered or were recovering on varenicline withdrawal and there were no consistent alternative explanations. Thirteen patients experienced single events, and two had multiple events. Frequency was not stated for the remaining two patients. Conclusions: The descriptions of the reports of aggression during sleep with violent dreaming are similar to those of rapid eye movement sleep behavior disorder and also nonrapid eye movement (NREM) sleep parasomnias in some adults. Patients who experience somnambulism or dreams of a violent nature while taking varenicline should be advised to consult their health providers. Consideration should be given to clarifying the term sleep disorders in varenicline product information and including sleep related harmful and potentially harmful events. Citation: Savage RL, Zekarias A, Caduff-Janosa P. Varenicline and abnormal sleep related events. SLEEP 2015

  2. Abnormal Activity Detection Using Pyroelectric Infrared Sensors

    PubMed Central

    Luo, Xiaomu; Tan, Huoyuan; Guan, Qiuju; Liu, Tong; Zhuo, Hankz Hankui; Shen, Baihua

    2016-01-01

    Healthy aging is one of the most important social issues. In this paper, we propose a method for abnormal activity detection without any manual labeling of the training samples. By leveraging the Field of View (FOV) modulation, the spatio-temporal characteristic of human activity is encoded into low-dimension data stream generated by the ceiling-mounted Pyroelectric Infrared (PIR) sensors. The similarity between normal training samples are measured based on Kullback-Leibler (KL) divergence of each pair of them. The natural clustering of normal activities is discovered through a self-tuning spectral clustering algorithm with unsupervised model selection on the eigenvectors of a modified similarity matrix. Hidden Markov Models (HMMs) are employed to model each cluster of normal activities and form feature vectors. One-Class Support Vector Machines (OSVMs) are used to profile the normal activities and detect abnormal activities. To validate the efficacy of our method, we conducted experiments in real indoor environments. The encouraging results show that our method is able to detect abnormal activities given only the normal training samples, which aims to avoid the laborious and inconsistent data labeling process. PMID:27271632

  3. Autism and chromosome abnormalities-A review.

    PubMed

    Bergbaum, Anne; Ogilvie, Caroline Mackie

    2016-07-01

    The neuro-behavioral disorder of autism was first described in the 1940s and was predicted to have a biological basis. Since that time, with the growth of genetic investigations particularly in the area of pediatric development, an increasing number of children with autism and related disorders (autistic spectrum disorders, ASD) have been the subject of genetic studies both in the clinical setting and in the wider research environment. However, a full understanding of the biological basis of ASDs has yet to be achieved. Early observations of children with chromosomal abnormalities detected by G-banded chromosome analysis (karyotyping) and in situ hybridization revealed, in some cases, ASD associated with other features arising from such an abnormality. The introduction of higher resolution techniques for whole genome screening, such as array comparative genome hybridization (aCGH), allowed smaller imbalances to be detected, some of which are now considered to represent autism susceptibility loci. In this review, we describe some of the work underpinning the conclusion that ASDs have a genetic basis; a brief history of the developments in genetic analysis tools over the last 50 years; and the most common chromosome abnormalities found in association with ASDs. Introduction of next generation sequencing (NGS) into the clinical diagnostic setting is likely to provide further insights into this complex field but will not be covered in this review. Clin. Anat. 29:620-627, 2016. © 2016 Wiley Periodicals, Inc. PMID:27012322

  4. Apparent Ruvalcaba syndrome with genitourinary abnormalities.

    PubMed

    Bialer, M G; Wilson, W G; Kelly, T E

    1989-07-01

    The Ruvalcaba syndrome is a rare malformation syndrome characterized by skeletal dysplasia, facial anomalies, and mental retardation. We report on a 22-year-old woman with severe growth and mental retardation and numerous manifestations characteristic of the Ruvalcaba syndrome. In addition, she has several anomalies not previously described in the Ruvalcaba syndrome, including upslanting palpebral fissures, torus palatinus, hiatal hernia with gastroesophageal reflux, recurrent respiratory infections, pectus excavatum, equinovarous deformity, hypotonia, unilateral renal hypoplasia, an accessory ovary, and atretic fallopian tube. Review of published reports of Ruvalcaba syndrome confirms variability of the clinical and radiographic changes. Findings present in at least 50% of reported patients include mental retardation, short stature, pubertal delay, an abnormal nose (usually beaked) with hypoplastic nasal alae, microstomia with narrow maxilla, thin upper lip vermilion, broad hips, small hands, joint limitation, short fingers and toes, and vertebral abnormalities. Because 5 of the reported patients had renal abnormalities, a renal ultrasound or contrast study is indicated in the evaluation of these patients. Additional reports, particular from multiplex families, will be important to better characterize this syndrome. PMID:2679089

  5. Abnormal Activity Detection Using Pyroelectric Infrared Sensors.

    PubMed

    Luo, Xiaomu; Tan, Huoyuan; Guan, Qiuju; Liu, Tong; Zhuo, Hankz Hankui; Shen, Baihua

    2016-01-01

    Healthy aging is one of the most important social issues. In this paper, we propose a method for abnormal activity detection without any manual labeling of the training samples. By leveraging the Field of View (FOV) modulation, the spatio-temporal characteristic of human activity is encoded into low-dimension data stream generated by the ceiling-mounted Pyroelectric Infrared (PIR) sensors. The similarity between normal training samples are measured based on Kullback-Leibler (KL) divergence of each pair of them. The natural clustering of normal activities is discovered through a self-tuning spectral clustering algorithm with unsupervised model selection on the eigenvectors of a modified similarity matrix. Hidden Markov Models (HMMs) are employed to model each cluster of normal activities and form feature vectors. One-Class Support Vector Machines (OSVMs) are used to profile the normal activities and detect abnormal activities. To validate the efficacy of our method, we conducted experiments in real indoor environments. The encouraging results show that our method is able to detect abnormal activities given only the normal training samples, which aims to avoid the laborious and inconsistent data labeling process. PMID:27271632

  6. Abnormalities in Hippocampal Functioning with Persistent Pain

    PubMed Central

    Mutso, Amelia A.; Radzicki, Daniel; Baliki, Marwan N.; Huang, Lejian; Banisadr, Ghazal; Centeno, Maria Virginia; Radulovic, Jelena; Martina, Marco; Miller, Richard J.; Apkarian, A. Vania

    2012-01-01

    Chronic pain patients exhibit increased anxiety, depression, and deficits in learning and memory. Yet how persistent pain affects the key brain area regulating these behaviors, the hippocampus, has remained minimally explored. In this study we investigated the impact of spared nerve injury (SNI) neuropathic pain in mice on hippocampal-dependent behavior and underlying cellular and molecular changes. In parallel, we measured the hippocampal volume of three groups of chronic pain patients. We found that SNI animals were unable to extinguish to contextual fear and showed increased anxiety-like behavior. Additionally, SNI mice in comparison to sham animals exhibited hippocampal 1) reduced extracellular signal-regulated kinase (ERK) expression and phosphorylation, 2) decreased neurogenesis and 3) altered short-term synaptic plasticity. In order to relate the observed hippocampal abnormalities with human chronic pain, we measured the volume of human hippocampus in chronic back pain (CBP), complex regional pain syndrome (CRPS), and osteoarthritis patients (OA). Compared to controls, CBP and CRPS, but not OA, had significantly less bilateral hippocampal volume. These results indicate that hippocampus-mediated behavior, synaptic plasticity and neurogenesis are abnormal in neuropathic rodents. The changes may be related to the reduction in hippocampal volume we see in chronic pain patients, and these abnormalities may underlie learning and emotional deficits commonly observed in such patients. PMID:22539837

  7. Persistent Pain and Sensory Abnormalities after Abdominoplasty

    PubMed Central

    Finnerup, Kenneth; Andresen, Sven R.; Nikolajsen, Lone; Finnerup, Nanna B.

    2015-01-01

    Background: Persistent postsurgical pain is a well-recognized problem after a number of common surgical procedures, such as amputation, thoracotomy, and inguinal hernia repair. Less is known about persistent pain after cosmetic surgical procedures. We, therefore, decided to study the incidence and characteristics of persistent pain after abdominoplasty, which is one of the most frequent cosmetic surgical procedures. Methods: In September 2014, a link to a web-based questionnaire was mailed to 217 patients who had undergone abdominoplasty between 2006 and 2014 at the Department of Plastic Surgery, Aalborg University Hospital, Denmark. The questionnaire included questions about pain and sensory abnormalities located to the abdominal skin, and physical and psychological function; patient satisfaction with surgery was rated on a 4-point scale. Results: One hundred seventy patients answered the questionnaire. Fourteen patients (8.2%) reported pain within the past 7 days related to the abdominoplasty. Abnormal abdominal skin sensation was common and reported by 138 patients (81%). Sensory hypersensitivity was associated with the presence of persistent pain. Satisfaction with the procedure was reported by 149 (88%) patients. The majority of patients reported improvement on all physical and psychological factors. Patients with pain were more often disappointed with the surgery and unwilling to recommend the surgery. Conclusions: Overall, patients were satisfied with the procedure, although abnormal abdominal skin sensation was common. However, there is a risk of developing persistent neuropathic pain after abdominoplasty, and patients should be informed about this before surgery. PMID:26893986

  8. Abnormal calcium homeostasis in peripheral neuropathies

    PubMed Central

    Fernyhough, Paul; Calcutt, Nigel A.

    2010-01-01

    Abnormal neuronal calcium (Ca2+) homeostasis has been implicated in numerous diseases of the nervous system. The pathogenesis of two increasingly common disorders of the peripheral nervous system, namely neuropathic pain and diabetic polyneuropathy, has been associated with aberrant Ca2+ channel expression and function. Here we review the current state of knowledge regarding the role of Ca2+ dyshomeostasis and associated mitochondrial dysfunction in painful and diabetic neuropathies. The central impact of both alterations of Ca2+ signalling at the plasma membrane and also intracellular Ca2+ handling on sensory neuron function is discussed and related to abnormal endoplasmic reticulum performance. We also present new data highlighting sub-optimal axonal Ca 2+ signalling in diabetic neuropathy and discuss the putative role for this abnormality in the induction of axonal degeneration in peripheral neuropathies. The accumulating evidence implicating Ca2+ dysregulation with both painful and degenerative neuropathies, along with recent advances in understanding of regional variations in Ca2+ channel and pump structures, makes modulation of neuronal Ca2+ handling an increasingly viable approach for therapeutic interventions against the painful and degenerative aspects of many peripheral neuropathies. PMID:20034667

  9. Dynamic Abnormal Grain Growth in Molybdenum

    NASA Astrophysics Data System (ADS)

    Worthington, Daniel L.; Pedrazas, Nicholas A.; Noell, Philip J.; Taleff, Eric M.

    2013-11-01

    A new abnormal grain growth phenomenon that occurs only during continuous plastic straining, termed dynamic abnormal grain growth (DAGG), was observed in molybdenum (Mo) at elevated temperature. DAGG was produced in two commercial-purity molybdenum sheets and in a commercial-purity molybdenum wire. Single crystals, centimeters in length, were created in these materials through the DAGG process. DAGG was observed only at temperatures of 1713 K (1440 °C) and above and occurred across the range of strain rates investigated, ~10-5 to 10-4 s-1. DAGG initiates only after a critical plastic strain, which decreases with increasing temperature but is insensitive to strain rate. Following initiation of an abnormal grain, the rate of boundary migration during DAGG is on the order of 10 mm/min. This rapid growth provides a convenient means of producing large single crystals in the solid state. When significant normal grain growth occurs prior to DAGG, island grains result. DAGG was observed in sheet materials with two very different primary recrystallization textures. DAGG grains in Mo favor boundary growth along the tensile axis in a <110> direction, preferentially producing single crystals with orientations from an approximately <110> fiber family of orientations. A mechanism of boundary unpinning is proposed to explain the dependence of boundary migration on plastic straining during DAGG.

  10. Visual projections routed to the auditory pathway in ferrets: receptive fields of visual neurons in primary auditory cortex.

    PubMed

    Roe, A W; Pallas, S L; Kwon, Y H; Sur, M

    1992-09-01

    How does cortex that normally processes inputs from one sensory modality respond when provided with input from a different modality? We have addressed such a question with an experimental preparation in which retinal input is routed to the auditory pathway in ferrets. Following neonatal surgical manipulations, a specific population of retinal ganglion cells is induced to innervate the auditory thalamus and provides visual input to cells in auditory cortex (Sur et al., 1988). We have now examined in detail the visual response properties of single cells in primary auditory cortex (A1) of these rewired animals and compared the responses to those in primary visual cortex (V1) of normal animals. Cells in A1 of rewired animals differed from cells in normal V1: they exhibited larger receptive field sizes and poorer visual responsivity, and responded with longer latencies to electrical stimulation of their inputs. However, striking similarities were also found. Like cells in normal V1, A1 cells in rewired animals exhibited orientation and direction selectivity and had simple and complex receptive field organizations. Furthermore, the degree of orientation and directional selectivity as well as the proportions of simple, complex, and nonoriented cells found in A1 and V1 were very similar. These results have significant implications for possible commonalities in intracortical processing circuits between sensory cortices, and for the role of inputs in specifying intracortical circuitry. PMID:1527604

  11. Synaptic input to vasopressin neurons of the paraventricular nucleus (PVN)

    SciTech Connect

    Silverman, A.J.; Oldfield, B.J.

    1984-01-01

    Following injections of horseradish peroxidase into the PVN, retrogradely filled cells were found in regions of the limbic system known to contain glucocorticoid concentrating neurons. To determine if these regions which include the lateral septum, medial amygdala and ventral subiculum have a monosynaptic input to vasopressin neurons the authors developed a double label ultrastructural technique to simultaneously visualize immunoreactive neuropeptide and anterogradely transported HRP. Following injections of tracer into all three of these regions, HRP labeled fibers were seen at the light microscopic level to form a halo in the perinuclear, cell poor zone around the PVN. Ultrastructural examination of this area resulted in the discovery of a small number of limbic system synapses on vasopressin dendrites. In a similar fashion they were interested in determining the distribution of noradrenergic terminals on vasopressin neurons in the various subnuclei of the PVN. The authors have combined immunocytochemistry for vasopressin with radioautography for /sup 3/H-norepinephrine (NE) at the ultrastructural level. NE terminals were numerous in the periventricular zone, innervating both vasopressin containing dendrites and non-immunoreactive dendrites and cell bodies. These studies demonstrate the need for ultrastructural analysis of synaptic input to neurosecretory cells.

  12. Channeling of red and green cone inputs to the zebrafish optomotor response.

    PubMed

    Orger, Michael B; Baier, Herwig

    2005-01-01

    Visual systems break scenes down into individual features, processed in distinct channels, and then selectively recombine those features according to the demands of particular behavioral tasks. In primates, for example, there are distinct pathways for motion and form processing. While form vision utilizes color information, motion pathways receive input from only a subset of cone photoreceptors and are generally colorblind. To explore the link between early channeling of visual information and behavioral output across vertebrate species, we measured the chromatic inputs to the optomotor response of larval zebrafish. Using cone-isolating gratings, we found that there is a strong input from both red and green cones but not short-wavelength cones, which nevertheless do contribute to another behavior, phototaxis. Using a motion-nulling method, we measured precisely the input strength of gratings that stimulated cones in combination. The fish do not respond to gratings that stimulate different cone types out of phase, but have an enhanced response when the cones are stimulated together. This shows that red and green cone signals are pooled at a stage before motion detection. Since the two cone inputs are combined into a single 'luminance' channel, the response to sinusoidal gratings is colorblind. However, we also find that the relative contributions of the two cones at isoluminance varies with spatial frequency. Therefore, natural stimuli, which contain a mixture of spatial frequencies, are likely to be visible regardless of their chromatic composition. PMID:16079003

  13. Solar retinopathy without abnormal exposure: case report.

    PubMed

    Stock, Ricardo Alexandre; Savaris, Simone Louise; de Lima Filho, Erasmo Carlos Rodrigues; Bonamigo, Elcio Luiz

    2013-01-01

    Solar retinopathy is photochemical damage to the retina, usually caused, by direct or indirect solar observation resulting from the use of hallucinogenic drugs, mental disorders or during eclipses. There may be a loss of visual acuity. We report the case of a 38-year-old patient who presented with a clinical diagnosis of solar retinopathy in the left eye, no prior history of sun exposure, normal visual acuity and complaints of metamorphopsia. Optical coherence tomography showed a rupture of the retinal pigment epithelium, confirming class II solar retinopathy. Visual acuity tends to normalize after 3 to 9 months, but not always. Thus, there is a real need to educate people about using eye protection during sun exposure especially given that some people may be highly susceptible to retinal damage, which was presumably the case for this patient. Finally, we note the importance of optical coherence tomography in diagnosing solar retinopathy. PMID:23828473

  14. Declarative Visualization Queries

    NASA Astrophysics Data System (ADS)

    Pinheiro da Silva, P.; Del Rio, N.; Leptoukh, G. G.

    2011-12-01

    In an ideal interaction with machines, scientists may prefer to write declarative queries saying "what" they want from a machine than to write code stating "how" the machine is going to address the user request. For example, in relational database, users have long relied on specifying queries using Structured Query Language (SQL), a declarative language to request data results from a database management system. In the context of visualizations, we see that users are still writing code based on complex visualization toolkit APIs. With the goal of improving the scientists' experience of using visualization technology, we have applied this query-answering pattern to a visualization setting, where scientists specify what visualizations they want generated using a declarative SQL-like notation. A knowledge enhanced management system ingests the query and knows the following: (1) know how to translate the query into visualization pipelines; and (2) how to execute the visualization pipelines to generate the requested visualization. We define visualization queries as declarative requests for visualizations specified in an SQL like language. Visualization queries specify what category of visualization to generate (e.g., volumes, contours, surfaces) as well as associated display attributes (e.g., color and opacity), without any regards for implementation, thus allowing scientists to remain partially unaware of a wide range of visualization toolkit (e.g., Generic Mapping Tools and Visualization Toolkit) specific implementation details. Implementation details are only a concern for our knowledge-based visualization management system, which uses both the information specified in the query and knowledge about visualization toolkit functions to construct visualization pipelines. Knowledge about the use of visualization toolkits includes what data formats the toolkit operates on, what formats they output, and what views they can generate. Visualization knowledge, which is not

  15. Universal visualization platform

    NASA Astrophysics Data System (ADS)

    Gee, Alexander G.; Li, Hongli; Yu, Min; Smrtic, Mary Beth; Cvek, Urska; Goodell, Howie; Gupta, Vivek; Lawrence, Christine; Zhou, Jainping; Chiang, Chih-Hung; Grinstein, Georges G.

    2005-03-01

    Although there are a number of visualization systems to choose from when analyzing data, only a few of these allow for the integration of other visualization and analysis techniques. There are even fewer visualization toolkits and frameworks from which one can develop ones own visualization applications. Even within the research community, scientists either use what they can from the available tools or start from scratch to define a program in which they are able to develop new or modified visualization techniques and analysis algorithms. Presented here is a new general-purpose platform for constructing numerous visualization and analysis applications. The focus of this system is the design and experimentation of new techniques, and where the sharing of and integration with other tools becomes second nature. Moreover, this platform supports multiple large data sets, and the recording and visualizing of user sessions. Here we introduce the Universal Visualization Platform (UVP) as a modern data visualization and analysis system.

  16. Characteristics of visual interference with visuospatial working memory.

    PubMed

    Toms, M; Morris, N; Foley, P

    1994-02-01

    Recent discussions of visuospatial working memory have suggested that this subsystem may incorporate a visual buffer which holds visuospatial information relatively passively. Empirical investigations of visual interference with information held within a visuospatial subsystem have yielded somewhat equivocal results. Nonetheless, evidence from Logie (1986) has indicated that visuospatial processing can be disrupted by passive exposure to irrelevant visual material in a manner analogous to the disruption of serial verbal recall by exposure to irrelevant speech. This paper reports two experiments which explore whether such irrelevant visual input is disruptive to storage of imaginal information in a primarily spatial task--the Brooks spatial matrix task. Experiment 1 shows that exposure to irrelevant visual input during encoding selectively disrupts performance on a spatial, but not a verbal, version of the task. The extent of such disruption is shown to be independent of the visual complexity of the material, its similarity to the to-be-remembered information, or a change in state, with a static white square pattern yielding equivalent disruption to that produced by changing matrix patterns. The second experiment indicates that this pattern of effects is robust, and that such disruption is evident at an equivalent level when the visual material is present only during a 20-second retention interval. These results are interpreted as evidence of obligatory access of external visual material to a passive visual buffer. Implications for the nature of a visuospatial subsystem in working memory are discussed. PMID:8167974

  17. Dyslexia: the Role of Vision and Visual Attention.

    PubMed

    Stein, John

    2014-01-01

    Dyslexia is more than just difficulty with translating letters into sounds. Many dyslexics have problems with clearly seeing letters and their order. These difficulties may be caused by abnormal development of their visual "magnocellular" (M) nerve cells; these mediate the ability to rapidly identify letters and their order because they control visual guidance of attention and of eye fixations. Evidence for M cell impairment has been demonstrated at all levels of the visual system: in the retina, in the lateral geniculate nucleus, in the primary visual cortex and throughout the dorsal visuomotor "where" pathway forward from the visual cortex to the posterior parietal and prefrontal cortices. This abnormality destabilises visual perception; hence, its severity in individuals correlates with their reading deficit. Treatments that facilitate M function, such as viewing text through yellow or blue filters, can greatly increase reading progress in children with visual reading problems. M weakness may be caused by genetic vulnerability, which can disturb orderly migration of cortical neurones during development or possibly reduce uptake of omega-3 fatty acids, which are usually obtained from fish oils in the diet. For example, M cell membranes require replenishment of the omega-3 docosahexaenoic acid to maintain their rapid responses. Hence, supplementing some dyslexics' diets with DHA can greatly improve their M function and their reading. PMID:25346883

  18. Electrocardiographic abnormalities in centenarians: impact on survival

    PubMed Central

    2012-01-01

    Background The centenarian population is gradually increasing, so it is becoming more common to see centenarians in clinical practice. Electrocardiogram abnormalities in the elderly have been reported, but several methodological biases have been detected that limit the validity of their results. The aim of this study is to analyse the ECG abnormalities in a prospective study of the centenarian population and to assess their impact on survival. Method We performed a domiciliary visit, where a medical history, an ECG and blood analysis were obtained. Barthel index (BI), cognitive mini-exam (CME) and Charlson index (ChI) were all determined. Patients were followed up by telephone up until their death. Results A total of 80 centenarians were studied, 26 men and 64 women, mean age 100.8 (SD 1.3). Of these, 81% had been admitted to the hospital at least once in the past, 81.3% were taking drugs (mean 3.3, rank 0–11). ChI was 1.21 (SD 1.19). Men had higher scores both for BI (70 -SD 34.4- vs. 50.4 -SD 36.6-, P = .005) and CME (16.5 -SD 9.1- vs. 9.1 –SD 11.6-, P = .008); 40.3% of the centenarians had anaemia, 67.5% renal failure, 13% hyperglycaemia, 22.1% hypoalbuminaemia and 10.7% dyslipidaemia, without statistically significant differences regarding sex. Only 7% had a normal ECG; 21 (26.3%) had atrial fibrillation (AF), 30 (37.5%) conduction defects and 31 (38.8%) abnormalities suggestive of ischemia, without sex-related differences. A history of heart disease was significantly associated with the presence of AF (P = .002, OR 5.2, CI 95% 1.8 to 15.2) and changes suggestive of ischemia (P = .019, OR 3.2, CI 95% 1.2-8.7). Mean survival was 628 days (SD 578.5), median 481 days. Mortality risk was independently associated with the presence of AF (RR 2.0, P = .011), hyperglycaemia (RR 2.2, P = .032), hypoalbuminaemia (RR 3.5, P < .001) and functional dependence assessed by BI (RR 1.8, P = .024). Conclusion Although ECG abnormalities are

  19. High prevalence of anterolateral ligament abnormalities in magnetic resonance images of anterior cruciate ligament-injured knees.

    PubMed

    Claes, Steven; Bartholomeeusen, Stijn; Bellemans, Johan

    2014-03-01

    The purpose of this study was to identify the newly described anterolateral ligament of the human knee on magnetic resonance imaging and to describe its eventual radiological abnormalities in anterior cruciate ligament-injured subjects. A retrospective cohort study on a series of consecutive subjects undergoing anterior cruciate ligament reconstructive surgery was performed. The MR images of 206 included knees were studied and the status of the anterolateral ligament status was judged to be either "non-visualized", "normal" or "abnormal". Of all the visualized anterolateral ligaments, 44 (21.3%) were considered uninjured, while 162 (78.8%) knees demonstrated radiological ALL abnormalities. The majority of ALL abnormalities were situated in the distal part of the ligament (77.8%). In conclusion, the anterolateral ligament can be identified on classic knee magnetic resonance images. Although anterior cruciate ligament injured subjects often demonstrated associated anterolateral ligament lesions, further research is needed in order to establish the clinical relevance of these highly frequent radiological abnormalities. PMID:24873084

  20. Precise lamination of retinal axons generates multiple parallel input pathways in the tectum

    PubMed Central

    Robles, Estuardo; Filosa, Alessandro; Baier, Herwig

    2013-01-01

    The axons of retinal ganglion cells (RGCs) form topographic connections in the optic tectum, recreating a two-dimensional map of the visual field in the midbrain. RGC axons are also targeted to specific positions along the laminar axis of the tectum. Understanding the sensory transformations performed by the tectum requires identification of the rules that control the formation of synaptic laminae by RGC axons. However, there is little information regarding the spatial relationships between multiple axons as they establish laminar and retinotopic arborization fields within the same region of neuropil. Moreover, the contribution of RGC axon lamination to the processing of visual information is unknown. We have utilized Brainbow genetic labeling to visualize groups of individually identifiable axons during the assembly of a precise laminar map in the tectum. Live imaging of multiple RGCs revealed that axons target specific sublaminar positions during initial innervation and maintain their relative laminar positions throughout early larval development, ruling out a model for lamina selection based on iterative refinements. During this period of laminar stability, RGC arbors undergo structural rearrangements that shift their relative retinotopic positions. Analysis of cell type-specific lamination patterns revealed that distinct combinations of RGCs converge to form each sublamina, and this input heterogeneity correlates with different functional responses to visual stimuli. These findings suggest that lamina-specific sorting of retinal inputs provides an anatomical blueprint for the integration of visual features in the tectum. PMID:23486973