Abstract: The corpus callosum is the largest neural pathway connecting the two cerebral hemispheres in mammals. Not only does it transmit information between the hemispheres, but also regulates interhemispheric information processing. “Inhibitory model” and “excitatory model” are the primary models proposed to explain the regulation mechanisms. The former hypothesized that the corpus callosum could inhibit the transfer of information between the hemispheres, so that the function of the dominant hemisphere was enhanced and the activity of non-dominant hemisphere was suppressed. As a result, the independence of the processing information in each hemisphere and the degree of the cerebral functional lateralization could be increased. In contrast, the latter assumed that the corpus callosum might play an excitatory role in interhemispheric transfer of information. According to the excitatory model, both hemispheres would be activated simultaneously and the interhemispheric connectivity would be strengthened. This mechanism might reduce the cerebral functional asymmetry and facilitate the share and the integration of interhemispheric information. However, some new evidence showed that the corpus callosum is not a single structural and functional body, but consists of multiple information processing channels separating or interacting spatially and temporally. Inhibitory and excitatory information could be transmitted separately between cerebral hemispheres through these different spatial channels at different speeds. Meanwhile, this information transfer might be regulated by task-computing types and task complexity. Therefore, the coordination of inhibition and excitation of the corpus callosum could regulate the dynamic interactions between the two cerebral hemispheres.

Key words: corpus callosum, inhibitory model, excitatory model, dynamic interhemispheric interactions