Sperry And Gazzaniga

Discuss how Sperry and Gazzaniga’s research has contributed to a greater understanding of brain lateralization and localization. Before attempting to understand this question and to answer it justifiably one should make clear what brain lateralization and localization is and what are the differences between them. Localization refers to the specific area of the brain that is responsible for a specific function. For example people who suffer from Broca's and Wernicke's aphasia, are prime examples of disorders which are the result of damage to a localized area (known as Broca's area and Wernicke's area) which leads to different types of aphasia. Lateralization refers to the differences between right hemisphere and left hemisphere brain functioning.

For instance in the majority of patients it was evident that they favored the right side of the body in fact for a large amount of time after the injury it was clear that the left side of the body rarely showed activity and wasn’t responsive to any stimulation. For example, when responding to sensory stimuli the patients favored the right side of the body, which is controlled by the dominant left half of the brain whereas the left side of the body was rarely active(when he brushed against something with his left side he did not notice that he had done so, and when an object was placed in his left hand he generally denied its presence). This observation now called bisected brain syndrome was further validated by visual auditory and other motor tests. In all tests the subject had one side which was more dominant than the other, effectively giving Gazzinga and his team the conclusion that various functions carried out by the body are indeed subject to localization in certain areas of the brain, however Gazzinga also unearthed new information on the lateralization of the Brain. This was best exemplified in a visual study to check the responses of visual

Therefore this next experiment was done to figure out what parts of the brain are localized in the right side. It turns out the ability for the human brain for construction from visual stimuli seems to lie in the right hemisphere which is why patients could only draw 3d shapes with their left hand(non dominant). Tests by Gazzinga and by Bogen have shown that in these patients the left hand is capable of arranging blocks to match a pictured design and of drawing a cube in three dimensions, whereas the right hand, deprived of instructions from the right hemisphere could not perform either of these