The P300 event-related potential (ERP) was elicited
in left- and right-handed young adult male and female participants
(n = 20/group) with both auditory and visual stimulus
discrimination tasks that varied systematically in difficulty.
P300 amplitude was larger across all task conditions for
left- than for right-handed participants at anterior and
central electrode sites. P300 latency was shorter across
all task conditions for left- than for right-handers. Task
difficulty did not affect the ERP handedness differences.
Male and female subjects demonstrated comparable ERP handedness
effects, although smaller P300 components were obtained
for males than for females. When considered in the context
of corpus callosal size differences for left- versus right-handed
and male versus female participants, the findings suggest
that the P300 reflects callosal size and interhemispheric
transmission efficacy.