Interhemispheric transfer without forebrain commissures

Abstract Surglcal sectlon of the corpus callosum (CC) usually produces disconnection deflcits. The absence of disconnection symptoms In Individuals born without a CC has been attributed to the use of residual commlssures, such as the anterlor commissure (AC). The aim of the present study was to evaluate interhemlspheric transfer of sensory and cognitive information In a patient who lacks both the CC and the AC. Flrst, to assess transfer of sensory informatlon, Interhemispheric transmission times (Ins) to simple visual, auditory and somesthetic stimuli were measured using Poffenberger's paradigm. Second, a visual letter dlscrlmlnatlon task was used to evaluate Interhemispheric transfer of cognitive information. Subjects made a samddlfferent judgment based on the physlcal or the lexical characteristics of the stlmull by pressing one of two response keys. Results of the sensory tasks showed that the visual and somesthetic IlTs of the agenetlc subject were slgniflcantly longer than those of controls, whereas ...