[Interzonal transcallosal connections of the visual and parietal cortices]

Interzonal transcallosal EPs induced by the stimulation of contralateral visual cortex were recorded all over parietal cortex and had two forms: positive-negative and negative-positive ones. The former EPs had a greater latency and peaks of phases whereas the amplitudes of similar components of contrphasic potentials did not differ much. Negative-positive EPs disappeared after section of the corpus callosum whereas positive-negative EPs practically did not change. Analogous changes of contrphasic responses occurred after section of intracortical projections on the side of recording and/or on the side of stimulation. Interzonal transcallosal responses are characterized by a functional interhemisphere asummetry. The amplitude of early components of any EPs proved to be higher and the latency longer in the right hemisphere. The left hemisphere had a larger delayed positive wave.