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| Neuropsychology and neuroscience in general have a history that is quite a bit older than one would think. Written records of the nervous system date back as far as 1700 B.C. But the bulk of knowledge about the brain and its functions did not become known until the 17th century. This is when men like Rene Descartes and Thomas Willis began studying the human nervous system and how it worked. | ||
| Rene Descartes (1596-1650) was the first scholar of note to make inclinations about the brain having an effect on behavior. He proposed that movements and subsequent behaviors were caused by the flow of 'animal spirits' through the nerves. Descartes saw the nerves as hollow tubes that transported the fluid causing muscles to be stimulated. This is known as the mechanistic view of behavior. Descartes got the idea when he saw the animated statues of St. Germaine. These were mechanical statues that operated on water that flowed through tubes in the statues themselves. If you would like to learn more about Descartes and his views go here. |  |
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The first detailed 'Anatomy of the Brain' was by Thomas Willis. It was published in 1664. Willis had a different view of the brain than did Descartes. He felt that the structures of the brain itself had influence on behavior, rather than the cerebral spinal fluid or the ventricles. Thomas also found that there were two types of tissue in the brain; gray matter and white matter. The gray matter made up the outer cortex of the brain while the white matter was the fibrous connective tissue found elsewhere in the brain. Willis did however agree with Descartes about the matter of the spirits. He felt that the white matter was a series of channels used to distribute the spirits that were generated in the gray matter. |
| Even with Thomas' detailed findings, the brain did not come under specific scientific study until the 1800's. |
Franz Josef Gall |
One particular offshoot of neuroscience that had its heart in the right place was phrenology. Phrenology translates to 'science of the mind' and is the study of the topography of a person's skull in relation to their brain anatomy. This would then allow for psychological diagnoses to be made just from examining a patient's skull. This technique was developed by Franz Josef Gall. Gall was an accomplished scientist who had done experiments and extensive structural analyses of the brain (human and animal). He found that the larger the brain, the more complex, flexible, and intelligent behavior the organism could engage in. He also made the statement that the brain was the center of higher mental activity. |  Phrenology
bust. |
| This movement was discredited however. It was done through the work of Pierre Flourens, who conducted experiments to show how sections of the brain had different functions than what the phrenologists had proposed. Flourens did this through the process of ablation, or removing parts of the brain in order to determine the function or role of a certain area. |
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One important theory that came from the ideas of phrenology is the theory of localization. This theory postulates that there are specific areas of the brain that perform specific jobs. This theory was supported by the likes of Paul Broca (1824-1880). Broca was interested in how damage to the brain affected people. One famous case was dealt with a man named "Tan". He was called this because that is all he could say. After the man died, Broca performed an autopsy and found a portion of the man's frontal cortex on the left side to be damaged by a lesion. From studying Tan's brain, and other like him, Broca found that that specific area of the brain had control over the expression of language. The people with damage to this area can still read and write, but have trouble verbalizing. This area is now called Broca's area. | |
Brain of patient with damage to Broca's area. |
Behavior and the Brain
The brain has really only recently been linked to the behaviors of individuals. This was begun in the 1900's when scientists started to look at how the mind affected people's behaviors.
1913- John Watson presents his theory that human behavior is based upon conditioned responses to stimuli. His theory goes against the eugenics theory which is reaching its height at this time. This marks the beginning of the behaviorist school of psychology.
Eugenics- The theory that human behavior is an inherited trait.
1930's- Scientists try to affect the workings of the brain in order to treat mental illnesses such as anxiety, depression, and schizophrenia.
Lobotomy- Developed by Moniz, was the surgical severing of connections in the frontal lobe of patients. Resulted in adverse side effects such as mood problems and changes in personality.
Electro-shock Therapy- Developed by Cerletti and Boni. Used electrical shocks to induce positive chemical changes in the brain. This like lobotomy had detrimental side effects.
The use of both of these techniques declined in the 1950's after the development of the medication Thorazine.
1950's and 60's- Wilder Penfield identified specific areas of the brain that control motor impulses, sensory inputs, and memories.
1970's and 80's- New scanning devices like the CT scanner and MRI allow for detailed mapping of the brain's functions.
1975- The roles of brain chemicals such as endorphins are discovered. Behavior is now thought of as a biochemical event.
1990's- With new knowledge more effective drugs are developed for the treatment of mental illnesses.
Genes also are beginning to be studied in order to see if there are ties to behaviors. This could lead to evidence supporting eugenics or knowledge that could link eugenics and behaviorism together.
Current Developments in Neuroscience
Gene therapy being used to treat Alzheimer patients: Genetically altered cells are being injected into areas of the brain that produce a vital chemical called acetylcholine. This chemical is essential for normal brain functions such as memory. The altered genes are infused with nerve growth factor (NGF) that allows for the acetylcholine producing cells to be rejuvenated.
Stem Cell Research: Scientists now are attempting to use bone marrow cells to create new brain and nerve cells. This could possibly replace the use of fetal stem cells, but it is unclear whether or not the new cell will function as nerve cells.