Brains, Rewards and AddictionTerrence J. Sejnowski, professor and head of the Computational Neurobiology Laboratory, is a pioneer in the field of computational neuroscience.
Among other things, Sejnowski is interested in the hippocampus, believed to play a major role in learning and memory; and the cerebral cortex, which holds our knowledge of the world and how to interact with it. In his lab, Sejnowski's team uses sophisticated electrical and chemical monitoring techniques to measure changes that occur in the connections among nerve cells in the hippocampus during a simple form of learning. They use the results of these studies to instruct large-scale computers to mimic how these nerve cells work. By studying how the resulting computer simulations can perform operations that resemble the activities of the hippocampus, Sejnowski hopes to gain new knowledge of how the human brain is capable of learning and storing memories. This knowledge ultimately may provide medical specialists with critical clues to combating Alzheimer's disease and other disorders that rob people of the critical ability to remember faces, names, places and events.
Lecture Overview
Why do we make certain decisions? For example, are you motivated to study for a class at the beginning of the semester when the first exam is over a month away? Would you baby-sit on a Saturday night? If you had to give up a party, but would be paid double, would you consider missing your party? What encourages you to get involved in volunteer work?
There are circuits of nerve cells in the brains of humans and other animals that act as a reward system. They create pleasurable feelings when we engage in adaptive behaviors, making us want to repeat the task. Unfortunately, by inappropriately activating these neural circuits, drugs can hijack them. Activation of the reward system has a very powerful impact on behavior. For example, if a rat receives stimulation to the reward center in its brain when it presses a lever, it will continue to press the lever, actually ignoring food and eventually starving to death.
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