The Split Brain: Some Thoughts :: Biology Essays Research Papers

The Split Brain: Some Thoughts "Left, right, left, right--the marching song of the two-mind movement. To hear them talk, you'd think that everyone had a second mind, suppressed by the first. That the vocal left brain dominated the poor artistic right brain. Preventing it from getting a creative thought in edgewise. Soon there will be a consciousness raising movement: Stop referring to the left cerebral hemisphere as the "dominant" one. Invent a more egalitarian term like co-chairperson. Co-chairhemisphere?" William H. Calvin, "Left Brain, Right Brain: Science or the New Phrenology." The brain is separated into two hemispheres in your brain, the right and the left. At first glance these hemispheres appear to be mirror images of one another, but on closer observations the two hemispheres have highly specialized regions that serve differing functions (1). In general, the right hemisphere interprets information and controls actions of the left side of the body. The left hemisphere interprets information and controls actions of the right side of the body. A thick band of fiber called the corpus callosum connects the two hemispheres. Evidently if the connection between the hemispheres is severed, a once common practice to relieve epileptic attacks, sensory information cannot pass to the correct region of the brain in order for a corresponding response to be made (2). Thus, your brain is SPLIT...! To me the split brain theory seemed a bizarre notion. Isn't my brain a whole- controlled by the centrally located "little man" who receives my thoughts, processes and multiple functions of my brain? If this is true how could the brain be split into two? Do you have two "yous" then? The split brain effect was first discovered by Roger Sperry and Ronald Meyers in the early 1960s (3). Meyers and Sperry showed that when the cat had its optic chiasm and corpus callosum severed, two independent learning centers were established - one in each hemisphere of the cat's brain. If the cat had its right eye open and its left eye covered and learned to make a simple conditioned response, it was unable to make the same response when the right eye was covered and the left eye was open. It was as if the learning was unable to be communicated to the other side of the brain (2); thus, it was obvious that information available to one side remained off-limits to the other.