Effective binocular integration at the midline requires the corpus callosum.
To study the role of the corpus callosum (CC) in midline binocular integration, the effects of late callosotomy and congenital CC agenesis on the ability to perceive dichoptic plaid motion was assessed. Coherent motion was well perceived at all locations in the visual field under dioptic viewing but not along the vertical meridian (VM) when the components were dichoptically presented. This deficit was totally abolished in the agenesis subject and reduced in the callosotomized individual when stimulus size was increased beyond the VM. Electrophysiological correlates were also examined by recording visual evoked potentials and these showed that the P1/N2 components were abnormal for small dichoptic stimuli presented on the midline. These findings attest to the importance of the contribution of CC to midline binocular integration and the effects of cerebral plasticity.
Saint-Amour
Dave
D
Groupe de Recherche en Neuropsychologie et Cognition, Département de Psychologie, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Canada H3C 3J7.
Lepore
Franco
F
Lassonde
Maryse
M
Guillemot
Jean-Paul
JP
D000328:Adult; D061085:Agenesis of Corpus Callosum; D016022:Case-Control Studies; D003337:Corpus Callosum / Q000502:physiology*; D003867:Depth Perception / Q000502:physiology*; D004192:Discrimination, Psychological; D004569:Electroencephalography / Q000379:methods; D004594:Electrophysiology / Q000379:methods; D005074:Evoked Potentials, Visual; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D011601:Psychophysics / Q000379:methods; D012858:Size Perception; D015348:Vision, Binocular / Q000502:physiology*; D014794:Visual Fields