Tools for Studying the Brain

 

In more authoritarian times, scientists believed that the brain had a strictly hierarchical organization. Each relay station was supposed to send increasingly complex information to a higher level until it reached the very top, where everything would somehow be put together.

Now scientists see the brain as a pattern processor and categorizer that recognizes which categories go together with a particular stimulus. Microelectrode techniques are used to study single neurons, whereas macroelectrode techniques are used to study overall activity in particular regions of the brain. Structural imaging techniques are used to map structures in the living brain. Functional imaging techniques observe neural activity as it reacts to sensory stimuli. A new field, computational neuroscience, studies neural networks and the interaction of neurons on behavior. As pointed out by Dr. Frederick Petty, a psychiatry professor at UT Southwestern, "You just can't do brain biopsies like you can do cardiac catheterizations." In the past 15 to 20 years, brain imaging technology has provided better pictures of mental illness and how drugs work. Brain scans have shown that people with depression have less nerve activity in the prefrontal regions that oversee complex thought. Brain imaging has also indicated that people with depression have a smaller hippocampus. Dr. Dwight German, also a professor at UT Southwestern, focused on a subregion of the thalamus and determined that people with schizophrenia have a million fewer nerve cells there. Dr. German is using a $1 million grant from the National Institute of Mental Health to map the thalamus. He indicated, however, that it is too early to determine if some mental illnesses are related to the structure of the brain. "We are just starting to scratch the surface really," German said in a recent article in the Dallas Morning News.

Dr. Dwight German, Professor, The Carl J. & Hortense M. Thomsen Chair in Alzheimer's Disease Research Department of Psychiatry UT Southwestern Medical Center.

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