Question

Describe the ground-breaking study of Myers and Sperry on split-brain cats. Explain why it has been so influential, and describe three of its contributions

Answer 1

In the 1950s and 1960s, Roger Sperry and his associate Myers performed experiments on cats, monkeys, and humans to study functional differences between the two hemispheres of the brain in the United States. To do so they studied the corpus callosum, which is a large bundle of neurons that connects the two hemispheres of the brain. Sperry severed the corpus callosum in cats and monkeys to study the function of each side of the brain. He found that if hemispheres were not connected, they functioned independently of one another, which he called a split-brain.

The experiment on split brain cats of Myers and Sperry showed that one function of the corpus callosum is to transfer learned information from one hemisphere to the other and when the corpus callosum is cut, each hemisphere can function independently; each split brain cat appeared to have 2 brains.

The experiment of Myers and Sperry established that one function of the corpus callosum is to transmit learned information between hemispheres, the key to studying the function of the cerebral commissures is to develop experimental procedures for presenting information to one hemisphere while keeping it out of the other, one hemisphere is capable of solving simple problems as rapidly as two hemispheres working together and the cerebral hemispheres are capable of functioning independently.

There was no other cure for people who suffered from a special kind of epilepsy than by cutting off the connection, corpus callosum, between the two hemispheres. Epilepsy is a kind of storm in the brain, which is caused by the excessive signaling of nerve cells, and in these patients, the brain storm was prevented from spreading to the other hemisphere when the corpus callosum was cut off. This made it possible for the patients to live a normal life after the operation.

Contributions

This research contributed greatly to understanding the lateralization of brain function. The lateralization of brain function is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other. The medial longitudinal fissure separates the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. Although the macrostructure of the two hemispheres appears to be almost identical, different composition of neuronal networks allows for specialized function that is different in each hemisphere.

The two hemispheres of split-brain patients can in fact learn two different things at once.

Split-brain patients can actually search for and identify a visual target item in an array of similar items more quickly than healthy controls can, presumably because the two hemispheres are conducting two independent searches at once.