The Use of Commissurotomy in Studies of Interhemispheric Communication

An overview is given of the structure and function of the mammalian cerebral commissures, with an emphasis on their role in interhemispheric communication. A major focus is placed on the use of commissurotomy as a method of selective disconnection of interhemispheric sensory-motor integration. In order for commissure section to be effective it is crucial that the sensory input is under total experimenter control. For example, in the split-brain preparation, the optic chiasma must also be sectioned as well as the corpus callosum in order to restrict the monocular visual input to a single hemisphere. Special consideration is given to differences in the commissural organisation in different species. These differences can mean that the same lesion can have different effects in various animal species. Finally, detailed surgical protocols for callosal and chiasma section are given separately for monkey, cat, rabbit, and rat. Each such surgical protocol is specifically tailored to each species’ neurosurgical vulnerabilities.