A5029856599- Visual perception and processing mechanisms
- Neural dynamics and brain function
- Retinal Development and Disorders
- Retinal Diseases and Treatments
- Face Recognition and Perception
- melanin and skin pigmentation
- Retinal Imaging and Analysis
- Ophthalmology and Visual Impairment Studies
- Vestibular and auditory disorders
- Color Science and Applications
- Advanced Neuroimaging Techniques and Applications
- Neural and Behavioral Psychology Studies
- Glaucoma and retinal disorders
- Retinal and Optic Conditions
- Tactile and Sensory Interactions
- Olfactory and Sensory Function Studies
- Morphological variations and asymmetry
- Optical Imaging and Spectroscopy Techniques
- Color perception and design
- Spatial Neglect and Hemispheric Dysfunction
- Multisensory perception and integration
- EEG and Brain-Computer Interfaces
- Motor Control and Adaptation
- Functional Brain Connectivity Studies
- Photoreceptor and optogenetics research
University of York
2016-2025
Biomedical Research Institute
2019-2023
Hull York Medical School
2012-2021
University College London
1995-2011
Moorfields Eye Hospital NHS Foundation Trust
2011
Royal Holloway University of London
2001-2010
Cognitive Neuroimaging Lab
2008
York University
2007
Imperial College London
1990-2003
Society for Neuroscience
2003
Two subdivisions of human V5/MT+: one located posteriorly (MT/TO-1) and the other more anteriorly (MST/TO-2) were identified in participants using functional magnetic resonance imaging on basis their representations ipsilateral versus contralateral visual field. These then targeted for disruption by application repetitive transcranial stimulation (rTMS). The rTMS was delivered to cortical areas while performed direction discrimination tasks involving 3 different types moving stimuli defined...
Recently, there has been evidence for considerable plasticity in primary sensory areas of adult cortex. In this study, we asked to what extent topographical maps human extrastriate reorganize after damage a portion visual (striate) cortex, V1. Functional magnetic resonance imaging signals were measured subject (G.Y.) with large calcarine lesion that includes most cortex but spares the foveal representation. When stimulation was present, intact lesioned occipital lobe exhibited conventional...
In albinism there is an abnormal projection of part the temporal retina to visual cortex contralateral eye. This projection, together with normally routed fibers from nasal retina, provides a cortical hemisphere input more than normal hemifield space. many mammalian models albinism, possible sensory mismatch in avoided either by reorganization thalamocortical connections give exclusive representation, or being substantially suppressed. this study we examine, fMRI, how human topographically...
Seminal work in the early nineties revealed that visual receptive field of neurons cat primary cortex can change location and size when artificial scotomas are applied. Recent now suggests these single neuron dynamics also pertain to neuronal population (pRF) be measured humans with functional magnetic resonance imaging (fMRI). To examine this further, we estimated pRF twelve healthy participants while masking central portion field. We found changes for two differently sized scotomas, most...
Human patients rendered cortically blind by lesions to V1 can nevertheless discriminate between visual stimuli presented their fields. Experimental evidence suggests that two response modes are involved. Patients either unaware or aware of the stimuli, which they able discriminate. However, under both conditions insist do not see. We investigate fundamental difference percepts derived for normal and affected hemifield in a human hemianope with he was aware. The psychophysical experiments we...
In this report, we evaluate the role of visual areas responsive to motion in human brain perception stimulus speed. We first identified and localized V1, V3A, V5/MT+ individual participants on basis blood oxygenation level-dependent responses obtained retinotopic mapping experiments moving gratings. Repetitive transcranial magnetic stimulation (rTMS) was then used disrupt normal functioning previously each participant. During rTMS application, were required perform delayed discrimination...
Abstract Symmetry is effortlessly perceived by humans across changes in viewing geometry. Here, we re‐examined the network subserving symmetry processing context of up‐to‐date retinotopic definitions visual areas. Responses object selective cortex, as defined functional localizers, were also examined. We further examined responses to both frontoparallel and slanted while manipulating attention toward away from symmetry. Symmetry‐specific first emerge V3 continue all downstream areas Of...
Visual Acuity (VA) and structural biomarker assessment before at 24-months after early detection routine treatment of second eye involvement with neovascular age-related macular degeneration (nAMD) additional comparison the first affected. Prospective, 22-centre observational study participants unilateral nAMD in Early Detection Neovascular AMD (EDNA) study, co-enrolled into Observing fibrosis, atrophy subretinal highly reflective material, intervention anti-VEGF (FASBAT) for an 2-year...
A full understanding of how we see our world remains a fundamental research question in vision neuroscience. While topographic profiling has allowed us to identify different visual areas, the exact functional characteristics and organization areas up hierarchy (beyond V1 & V2) is still debated. It hypothesized that area V4 represents vital intermediate stage processing spatial curvature information preceding object recognition. Advancements magnetic resonance imaging hardware acquisition...
We have examined visual functions, including colour vision, in a patient with bilateral cortical lesions involving mainly the fusiform and lingual gyri, areas known to be involved central processing of chromatic stimuli. The has near normal (6/9) acuity, his responses tests binocular function spatial vision are normal, as discrimination changes target speed surface lightness. He does, however, exhibit minor losses upper field, mild prosopagnosia topographical agnosia, all conditions commonly...
In human albinism a part of the temporal retina projects abnormally to contralateral hemisphere. An objective VEP procedure quantify extent abnormality was devised.Monocular VEPs were recorded in 16 subjects with and controls from occipital electrodes pattern-onset stimulation 1 10 adjacent rectangular apertures along horizontal meridian covering total +/-27 degrees. For each eye interhemispheric difference potentials calculated correlated other assess lateralization responses: positive...
There is clear evidence that spatial attention increases neural responses to attended stimuli in extrastriate visual areas and, a lesser degree, earlier areas. Other shows neurons representing unattended locations can also be suppressed. However, the extent which enhancement and suppression observed, their stimulus dependence, stages of system at they are expressed remains poorly understood. Using fMRI we set out characterize both task dependence lateral geniculate nucleus (LGN), primary...
Representations in early visual areas are organized on the basis of retinotopy, but this organizational principle appears to lose prominence extrastriate cortex. Nevertheless, an region, such as shape-selective lateral occipital cortex (LO), must still base its activation responses from earlier retinotopic areas, implying that a transition “functional” organizations should exist. We hypothesized may lie LO-1 or LO-2, two lying between retinotopically defined V3d and functionally LO. Using...
Abstract Albinism is a genetic condition associated with abnormalities of the visual system. Defects in melanin production cause underdevelopment fovea, reduced retinal cell numbers and abnormal routing ganglion nerve fibres at optic chiasm. We examined 19 subjects albinism 26 control to determine whether affect structure cortex. Whole‐brain, high‐resolution anatomical magnetic resonance imaging volumes from each subject were obtained on 1.5‐T scanner segmented into grey white matter. A...
purpose. To compare VEP and fMRI as a means of detecting the abnormal visual projections in albinism different stimulation conditions. methods. Cortical response to monocular full-field pattern-onset hemifield -reversal 18 subjects with known diagnosis albinism, 17 control subjects, 6 infantile nystagmus syndrome (INS) was determined by fMRI. An asymmetry index used quantify extent lateralization measured both The which each method stimulus combination differentiated participant groups...
The spatial sensitivity of the human visual system depends on stimulus color: achromatic gratings can be resolved at relatively high frequencies while to isoluminant color contrast tends more low-pass. Models early vision often assume that receptive field size pattern-sensitive neurons is correlated with their frequency - larger fields are typically associated lower optimal frequency. A strong prediction this model coding chromatic patterns should have, average, a than sensitive patterns....