Interocular transfer in the hooded rat

Cortical spreading depression was used as a means of providing a reversible split-brain in several experiments on interocular transfer in the hooded rat. It was shown that this phenomenon cannot be explained on the basis of the presence of a small number of ipsilateral fibers, but that central mechanisms are likely involved. Two such mechanisms were described: (1) the bilateral storage of memory traces during monocular learning, with the primary trace (hemisphere contralateral to the open eye) being stronger than the secondary trace (ipsilateral hemisphere); and, (2) the use of the traces in both hemispheres during monocular performance through the naive eye. Implications of these results for the general problem of interhemispheric communication are discussed.