Sperry and colleagues, including Michael Gazzaniga, conducted extensive experiments on an epileptic patient who had had his corpus collosum, the "bridge" between the left and right hemispheres of the brain, split so that the connection was severed. At first the patient seemed normal, but experimentation showed that certain activities, such as naming objects or putting blocks together in a prescribed way, could only be done when using one side of the brain or the other. (Since the right eye connects to the left brain, the left hand to the right brain, and so on throughout the body, the stimulus would be given to the side of the body opposite the brain hemisphere being tested.) These abilities were not absolute, but it seemed that the left hemisphere specializes in language processes and the right is dominant in visual-construction tasks. Sperry's work helped chart the brain and opened fields of new psychological and philosophical research. For his "left brain - right brain" research Sperry shared the Nobel prize in 1981.

Sperry's chemoaffinity hypothesis, which states that neurons make connections with their targets based on interactions with specific molecular markers^[1] and, therefore, that the initial wiring diagram of an organism is (indirectly) determined by its genotype. The markers are generated during cellular differentiation and aid not only with synaptogenesis, but also act as guidance cues for their respective axon."  Digital facsimile from PubMedCentral at this link.