Memory Lapses Come When 2 Parts of Brain Compete

FRIDAY Oct. 24, 2008 -- Competition between two areas of the brain involved in learning may explain common memory lapses, suggest Yale University researchers, who add that their findings may help lead to new treatments for drug abusers and people with obsessive-compulsive disorder (OCD).

One area is the striatum, which helps record cues or landmarks that guide you to familiar destinations. When the striatum goes on autopilot, you can arrive at a common destination, such as work, with little memory of the trip.

The other area is the hippocampus, which is used when traveling to an unfamiliar place. The hippocampus is part of the spatial learning system, which a commuter would use if he or she had to run an errand before arriving at work.

"When you have driven the same route many times and are doing it on autopilot, it can be really difficult to change," study senior author Dr. Christopher J. Pittenger, an assistant professor of psychiatry, said in a Yale news release. "This is why I cannot, for the life of me, remember to drop off my dry cleaning on the way to work. If I'm not paying enough attention right at the moment, if I am thinking about something else, I just sail right on by."

In this study, Pittenger and colleagues disrupted areas of the striatum in mice and found this impaired the rodent's ability to complete landmark navigation tasks, but actually improved their spatial learning ability.

When the researchers disrupted areas of the hippocampus involved in spatial learning, mice could no longer navigate spatially but learned landmark tasks more quickly, according to the study, published in this week's issue of the Proceedings of the National Academy of Sciences.

The interactions between these two brain systems may help researchers better understand and treat mental illnesses that cause destructive, habit-like behavior or thought patterns, such as OCD and drug addiction.

"This is part of what we are doing in cognitive-behavioral therapy when we teach patients to recognize their destructive habits, to take a step back, and to learn to do things differently," Pittenger said. "What we're really asking them to do is to use one of these systems to overcome and, ultimately, to re-train the other."

More information

PBS has more about memory.

Posted: October 2008


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