Visual information and evoked responses from the left and right hemispheres

Abstract

Average evoked responses (AER) to verbal and non-verbal stimuli were recorded from left and right occipital EEG leads in ten normal right-handed subjects. Although the two types of stimuli were carefully matched for physical properties, their evoked potential wave forms could be differentiated by means of a computational technique utilizing replicate evoked responses. AER wave forms for verbal and non-verbal stimuli were more different from the left hemispheric lead than from the right. Verbal stimuli had shorter AER latencies. Hemispheric differences in the AER are consistent with the hypothesis that the cerebral hemispheres in man assume an asymmetrical role in governing cognitive behavior.