The Cahill Laboratory at the University of California, Irvine

Focusing on Neural Mechanisms of Emotionally Influenced Memory

"Selection is the very keel on which our mental ship is built. And in the case of memory its utility is obvious. If we remembered everything, we should on most occasions be as ill off as if we remembered nothing."
-- William James, Principles of Psychology, 1890

This quote by the great American psychologist neatly summarizes the main thrust of our research. Most neuroscientists interested in memory study what they hope prove to be neural mechanisms mediating the formation of memory- the "memory trace." Just as important, in our view, will be understanding mechanisms which regulate the actual information storage mechanisms. We assume that the brain must possess the means to "weight" information storage according to the importance of the information to be stored. Such mechanisms are required so the brain may "select," to borrow William James' term, information for storage.

Our research focuses on neural mechanisms of memory formation for emotionally arousing events.

Although in the past we have pursued this goal using both animal and human subject models, our current work focuses primarily on human subject studies. We employ neuropharmacological, neuropsychological, and brain imaging approaches in these studies. Our research suggests that activation of beta-adrenergic receptors and the amygdala in humans are critical for enhanced conscious ("declarative") memory associated with emotional arousal. For example, we have found that beta-adrenergic blockade in healthy humans selectively impairs long-term memory for emotionally arousing material. Patients with selective damage to the amygdala show a similar deficit. Furthermore, amnesic patients with intact amygdalae demonstrate enhanced memory for emotional material despite their overall impaired memory performance.

Finally, human brain imaging studies are consistent with the neuropyschological findings in suggesting that amygdala activity in humans is selectively related to memory formation under conditions of emotional arousal.

More recently, our work is showing that sex and cerebral hemisphere constitute twin, interacting influences on brain mechanisms of emotion and memory that can no longer be ignored.

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