Spatial misperceptions in amblyopic vision: abnormal activation of the primary visual cortex?

Sireteanu, R., Bäumer, C., Sârbu, C., Tsujimura, S. and Muckli, L. (2007) Spatial misperceptions in amblyopic vision: abnormal activation of the primary visual cortex? Klinische Monatsblaetter fuer Augenheilkunde, 224(10), pp. 780-786. (doi: 10.1055/s-2007-963469)

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Abstract

<b>BACKGROUND</b>: The aim of this study was to provide a description of the spatial distortions and temporal instability in amblyopic vision, and to attempt to define a cortical substrate of the spatial distortions in strabismic amblyopia. <b>MATERIAL AND METHODS</b>: The perceptual distortions and instabilities occurring in amblyopic vision were investigated psychophysically, by asking 17 subjects to describe and sketch their percepts. This was then visualised with an animated computer programme and validated by the subjects. In a second experiment, the cortical responses of normal observers to patterns corresponding to the spatial distortions reported by amblyopic subjects were investigated using functional magnetic resonance imaging. <b>RESULTS</b>: Spatial distortions were more marked in strabismic than in anisometropic amblyopes or in strabismic subjects with alternating fixation. Temporal instability occurred mainly in strabismic amblyopes and affected mainly patterns with higher spatial frequencies. Experiments with functional magnetic resonance imaging showed that the patterns with the highest spatial distortions yield increased activation in the primary visual cortex of normally-sighted observers. <b>CONCLUSIONS</b>: The results of the imaging experiment suggest that the occurrence of spatial distortions might explain the higher activation in the primary visual cortex of some amblyopic subjects. The occurrence of temporal instability in strabismic amblyopia suggests an involvement of higher-order, extrastriate visual areas of the dorsal, "where" visual pathway in amblyopia, in addition to the known deficits in the ventral, "what" visual pathway.

Item Type:Articles
Additional Information:Article published in German under the title 'Basiert der verzerrte Seheindruck bei Amblyopie auf einer erhöhten Aktivierung in der primären Sehrinde?'
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Muckli, Professor Lars
Authors: Sireteanu, R., Bäumer, C., Sârbu, C., Tsujimura, S., and Muckli, L.
Subjects:B Philosophy. Psychology. Religion > BF Psychology
College/School:College of Science and Engineering > School of Psychology
College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Klinische Monatsblaetter fuer Augenheilkunde
ISSN:0023-2165
ISSN (Online):1439-3999

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