CALLOSAL TRANSMISSION TIME BEFORE AND AFTER PARTIAL COMMISSUROTOMY

INTERHEMISPHERIC transmission time was measured in a patient, before and after partial commissurotomy sparing the splenium of the corpus callosum, using a simple reaction time paradigm with unimanual responses to lateralized flashes at 4 degrees and 8 degrees of eccentricity. Post-operative transfer time was longer than pre-operative transfer time at 8 degrees but not at 4 degrees of eccentricity. These data do not support the notion that the callosal transfer time is always faster through motor rather than visual fibers. They rather suggest that the callosal transfer time through visual fibers is longer than the callosal transfer time through motor fibers only for flashes at large eccentricities.