The role of the corpus callosum and some subcortical commissures in interocular transfer in the hooded rat.

The effect of sectioning the corpus callosum on interocular transfer of a brightness and a horizontal/vertical discrimination was examined in hooded rats. Lesions of the posterior portion of the callosum usually led to moderate transfer deficits, but considerable individual variation was found. Lesions involving only the anterior part of the callosum had little effect on transfer. This suggests a functional localisation in the corpus callosum of the rat similar to that seen in higher mammals. Section of the posterior and tectal commissures and the thalamic massa intermedia in addition to the callosum had no greater effect on transfer thatn callosal section alone. It is therefore unlikely that these structures play a crucial role in interocular transfer in the rat.