Lesions

One of the ways that we lose our mental abilities is through the development of brain lesions. Whether from various diseases, traumas, other other sources, they all appear to end the same way, with some sort of disruption of mental facilities. While the lesion can be devastating and disruptive to an individual, it provides the opportunity for researchers to look at the mind that ethics and modern science would otherwise not allow. In experiments, good scientists look to control for every factor that they can. Experimenting with the human mind or brain, there have been temporary ways to knock out part of the brain as in the Wada test or through the use of TMS. However, to permanently remove some part of the brain would be unethical. With lesions of the brain, nature has made these temporary knock-outs permanent and has also made them (generally) very focally. Through the use of brain imaging techniques and behavioral assays, the location of the lesion can generally be identified. When a lesion is identified, testing to see how the loss of a certain part of the brain can begin.

Although some are not exact definitions of the lesion technique, the following names have offered much to the study of the brain through their loss of. Phineas Gage is probably one of the best known examples of the lesion. While working on a railroad in the 19th century, a tamping rod exploded and shot through the skull of Gage. He survived the accident, but his friends would later describe him as, "Gage was no longer Gage." It appears that the part of the brain that was lost in the accident was part of the system for regulating emotions and drive. Another example would include the man H.M. As a boy he suffered intractable seizures from epilepsy. His doctor (Scoville) decided to remove the areas from where the seizures were originating, which happened to be approximately 2/3 of the hippocampus, and surrounding area as well as the amygdala bilaterally. After the surgery it appeared that he had no memory for the present and was unable to form new memories. Years of testing (the rest of his life) has offered great insights into the function of the hippocamus and its role in memory. The last example is similar to H.M. Clive Wearing a former world class musician suffered encephalitis caused by the herpes virus which bilaterally wiped his hippocampus. He currently displays profound amnesia and has been dubbed "memento" (later a movie by the same name).

These are just three examples of thousands which demonstrate the accuracy and the power of the lesion method. Lesions in all parts of the brain are able to demonstrate the power and the function of these certain areas. While it is interesting to think about how the lesion method can teach us, piece by piece how the brain functions, it is also interesting to look at lesions in children. It appears that children are often able to recover and cope with the loss of certain brain areas fairly well. It is amazing to think about the plasticity and the adaptability of the brain at a young age.

The University of Iowa has the largest database of lesion patients. With the collaboration of the University Hospital and the patients themselves, the college is able to watch, learn and research with these interesting cases of the brain. It will be interesting to see what the lesion method can teach me.