ERP and RT signs of a rightward bias for spatial orienting in a split-brain patient.
Neuropsychological data have shown that the two cerebral hemispheres differ in the control of spatial attention. The present study investigated hemispheric asymmetries and visuomotor integration in a split-brain patient and three control subjects. Simple reaction times (RTs) and event-related potentials (ERPs) were recorded to lateralized stimuli presented at different eccentricities in the left and right visual hemifields. Both electrophysiological and behavioural data showed that, unlike controls, the split-brain patient showed a strong rightward attentional bias resulting in shorter RTs and larger P300 potentials to stimuli falling in the rightmost space. Furthermore, ERPs also showed that while the RH has a bilateral control of visual space, the LH spatial orienting capability is most restricted to the contralateral hemifield.
Proverbio
A M
AM
Center for Neuroscience, University of California, Davis.
Zani
A
A
Gazzaniga
M S
MS
Mangun
G R
GR
D000328:Adult; D001519:Behavior / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D003337:Corpus Callosum / Q000601:surgery; D004594:Electrophysiology; D004827:Epilepsy / Q000601:surgery*; D005071:Evoked Potentials; D007839:Functional Laterality; D006801:Humans; D008297:Male; D011930:Reaction Time; D014794:Visual Fields