Interhemispheric transfer of visuo-motor inputs in a split-brain patient: Electrophysiological and behavioral indexes

Marzi and colleagues described the case of two partially acallosal patients, suggesting that their interhemispheric transfer in a Poffenberger paradigm could be mediated by slow subcortical routes. Some discrepancies between the CUD in RTs and visual event-related potentials (ERPs), along with a dishomogeneity in lesion locus, make it difficult to compare the data of the two patients and draw any straightforward conclusion. We present ERP data of a commissurotomized patient engaged in selective attention tasks to lateralized patterned stimuli. These data provide evidence of a delayed synchronized evoked response affected by stimulus eccentricity over the disconnected nonviewing hemisphere, probably mediated by collicular subcortical pathways.