Individual differences in interhemispheric transfer time (IHTT) as measured by event related potentials

The present study examined possible gender differences in interhemisperic transfer time (IHTT), as measured by event related potentials (ERPs). Using visual half-field presentations of letter pairs in a match/no-match paradigm, N1 latency was measured for each visual half-field and hemisphere. IHTTs were determined by subtracting the "direct" (i.e., contralateral or non-callosal) pathway N1 latency from the "indirect" (i.e., callosal) pathway N1 latency. Based on studies showing gender differences in corpus callosum size and function, we hypothesized that females would show more symmetric and faster overall transfer times than males. Results showed faster right-to-left IHTT across all participants, but females had more symmetric IHTT and shorter overall IHTT--primarily due to significantly shorter left-to-right times compared to males. Little support was found for the influence of hemisphere (i.e., "direct" pathway) response, or potential lateralization of function, on the length of IHTT in either direction.