Lateralized suppression of dichotically presented digits after commissural section in man.

Right-handed patients with surgical disconnection of the cerebral hemispheres cannot report verbal input to the left ear if diferent verbal stimuli have been channeled simultaneously to the right ear. With monaural stimulation, they show equal accuracy of report for the two ears. These findings highlight the dominance of the contralateral over the ipsilateral auditory projection system. Suppression of right-ear input is obtained in nonverbal tests. Dissociation between verbal and left-hand stereognostic responses indicate a right-left dichotomy for auditory experience in the disconnected hemispheres.