Hemispheric differences for P300 amplitude from an auditory oddball task.

The P3(00) event-related potential (ERP) was elicited in 80 normal, right-handed male subjects using a simple auditory stimulus discrimination task, with electroencephalographic (EEG) activity recorded at 19 electrodes. P300 amplitude was larger over the right compared to left hemisphere electrode sites primarily at anterior-medial locations (F3/4, C3/4) for both target and standard stimuli. The N100, P200, and N200 components also demonstrated several similar, albeit less robust, hemispheric asymmetries. No hemispheric effects for P300 latency were observed, with few consistent latency findings for any of the other components obtained. The results suggest that the discrimination process underlying P300 generation may originate with right frontal activation.