February 19, 2013

Prof. David Smith Researches Memory Retrieval Triggers

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If you want to increase your grade on your next prelim or exam, take the test in same room in which you learned the material. According to Prof. David Smith, psychology, this is a form of contextual memory, or memory that can be recalled with better accuracy if a person is in the same setting where he or she first learned the information. Contextual memory is used by crime investigators to obtain more information from eyewitnesses. But eyewitnesses do not have to return to the scene of the crime to trigger contextual memories.

The simple act of closing one’s eyes and imagining oneself back at the crime scene, known as context reinstatement, can bring back a flood of memories that would otherwise be unreachable.

Smith focuses on pinpointing the areas in the brain that influence memory encoding and retrieval, specifically which area of the brain contributes most to the phenomenon of contextual memory.

To do this, Smith places rodents under general anesthesia and surgically introduces a tube into their brains, which is directly connected to the hippocampus, the area of the brain associated with memory.

Because the brain has no pain receptors, the rodents feel no pain or discomfort during or after the procedure.

Smith injects a small amount of Muscimol, a drug that shuts down the brain for a short period of time, into the rodents’ hippocampi.

According to Smith, without a functioning hippocampus, rodents can still learn and remember a signal in the form of an odor, but their ability to recall contextual memory is impaired.

The control group of rodents, which were not injected with Muscimol, were able to recall odors more precisely when they were in the same setting where they had first smelled the odors, but the experimental group of rodents did not show the same memory retrieval improvement.

According to Smith, previous studies on contextual memory in humans concluded that lists of items can be recalled with more precision at the same physical location they were learned.

In those studies, however, it was unclear which part of the brain was responsible for this phenomenon. Smith’s findings that the hippocampus controls contextual memory in rats can be translated to humans because rodent brain structure is similar to that of humans.

Aside from his research, Smith teaches Psychology 2230, Introduction to Biological Psychology, in the fall semester.

According to Smith, the class is “an introduction to how the brain works.” Students in his lecture learn about the functionality of the brain, including sensory systems, emotions and memories.

In the spring semester, he teaches a seminar that looks more deeply into one field within neurobiology. The topic changes each year, but this year, the seminar focuses on the hippocampus and its functions.

Smith also leads a year-round journal discussion, in which discusses a recent journal article in the field of neurobiology with students. The discussion is held every Tuesday and is open to graduate students and several advanced undergraduate students with permission.

Original Author: Amit Blumfield