Evidence for paracallosal verbal transfer after callosal section. A possible consequence of bilateral language organization.

The covert interhemispheric transfer of linguistic information was demonstrated in a commissurotomy patient with bilateral language organization. It was found that under conditions of unilateral stimulation, a verbal association established in one hemisphere was available to the untrained hemisphere as well. Such interhemispheric transfer was observed only for phonetically codable information. Moreover, transfer was not observed under conditions of simultaneous bilateral stimulation. These results suggest that the point of convergence between the left and right hemisphere language systems allows for the paracallosal transfer of linguistic information.