P300 AND HANDEDNESS - ON THE POSSIBLE CONTRIBUTION OF CORPUS CALLOSALSIZE TO ERPS

The P300 event-related potential (ERP) was elicited in left- and right -handed young adult male and female participants (n = 20/group) with b oth auditory and visual stimulus discrimination tasks that varied syst ematically in difficulty. P300 amplitude was larger across all task co nditions for left- than for right-handed participants at anterior and central electrode sites. P300 latency was shorter across all task cond itions for left- than for right-handers. Task difficulty did not affec t the ERP handedness differences. Male and female subjects demonstrate d comparable ERP handedness effects, although smaller P300 components were obtained for males than for females. When considered in the conte xt of corpus callosal size differences for left- versus right-handed a nd male versus female participants, the findings suggest that the P300 reflects callosal size and interhemispheric transmission efficacy.