The effect of dissection of corpus callosum on differentiation of instrumental reflexes to symmetrical tactile stimuli in dogs.

In normal dogs a differentiation task consisting of lifting the left or right foreleg in response to the tactile stimuli administered to the left or right side of the body respectively is very difficult, requiring from 500 to 1,000 trials. On the contrary the same task presented to other dogs after transection of the corpus callosum is mastered immediately after the animals have learned to perform the instrumental movements. These results are explained as being due to the role played by callosal connections in the transfer of the afferent information from one side of the body to the other side.