What Cruel Acts of Fate Teach Us about Brain Function
Much of the research and discoveries regarding how our brain functions can be attributed to cruel acts of fate- the brain injuries and disorders which damage key areas of the brain. It is through studying how these injuries and disorders affect human behavior, that we gain insight into how different brain structures contribute to human functional capability. The literature of neuropsychology is filled with countless case histories that document how specific brain lesions have affected a particular patient¹s abilities.
As early as 1868, the case of Phineas Gage provided us with an example of brain damage and how it can lead to discoveries about brain function. Phineas Gage, a dynamite worker, was involved in an explosion that drove a 1.25 inch-wide iron bar through the front of his head. Gage survived, but his behavior was completely changed. His friends who knew him well said he was another person. Once a calm man, his personality became belligerent. Gage¹s injury effected primarily his left frontal lobe. This case gave insight into how frontal lobe lesions can alter personality (Kolb & Whishaw, 1990).
Alexander Luria, the famous Russian neuropsychologist, expanded the use of the case history by studying one individual and his brain injury over 25 years. His book The Man With a Shattered World documents a patient¹s
struggle to overcome the cognitive deficits resulting from a bullet wound to the brain during World War II. Dr. Oliver Sacks has popularized the case study as a window into how the brain functions through his many articles and books including The Man Who Mistook His Wife For a Hat, in which he takes us into the strange world of Dr. P who suffered from an unusual syndrome called visual agnosia. Visual agnosia is a syndrome in which an individual is able to see, but is not able to attach meaning to what he sees (Weiten, 1998). Perhaps even more bizarre are recent case histories describing individuals who are able to perceive the world around them without any conscious knowledge of that perception. Studies of disorders such as blindsight, inverse Anton¹s Syndrome, prosapagnosia, and blind touch, provide us with an opportunity to understand the complex process of perception.
Blindsight is a pattern of behavior that is displayed by individuals who are blind due to a damaged striate cortex. In cases of blindsight, the patient claims not to see something within their field of view, but shows in their behavior that they are stimulated by this object that they claim not to be seeing (Natsoulas, 1997). Individuals with blindsight, despite their blindness, were able to look towards a stimulus in their field of view, and point to it, but not identify it. In one study, a patient with complete cortical blindness was presented with a large moving striped display. The patient was able to follow this moving stimulus with his eyes, but claimed that he could not see it. Research into...