Sunday, June 14, 2009

Memory and Fear

In today's excerpt - memory and fear. The emotion of each memory is chemically encoded in the brain's amygdala. And each memory is changed - chemically altered - each time we retrieve it, for better or for worse. Therapists try and use this in helping patients overcome fears:

"Learned fears [such as stage-fright] are acquired in part in circuitry centering on the amygdala, which Joseph LeDoux likes to call the brain's 'Fear Central.' LeDoux knows the neural terrain of the amygdala intimately; he's been studying this clump of neurons for decades at the Center for Neural Science at New York University. The cells in the amygdala where sensory information registers, and the adjacent areas that acquire fear, LeDoux has discovered, actually fire in new patterns at the moment a fear has been learned.

"Our memories are in part reconstructions. Whenever we retrieve a memory, the brain rewrites it a bit, updating the past according to our present concerns and understanding. At the cellular level, LeDoux explains, retrieving a memory means it will be 'reconsolidated,' slightly altered chemically by a new protein synthesis that will help store it anew after being updated.

"Thus each time we bring a memory to mind, we adjust its very chemistry: the next time we retrieve it, that memory will come up as we last modified it. The specifics of the new consolidation depend on what we learn as we recall it. If we merely have a flare-up of the same fear, we deepen our fearfulness.

"But, ... if at the time of the fear we tell ourselves something that eases its grip, then the same memory becomes reencoded with less power over us. Gradually, we can bring the once-feared memory to mind without feeling the rush of distress all over again. In such a case, says LeDoux, the cells in our amygdala reprogram so that we lose the original fear conditioning. One goal of therapy, then, can be seen as gradually altering the neurons for learned fear.

"Treatments sometimes actually expose the person to whatever primes their fear. Exposure sessions begin with getting the person relaxed, often through a few minutes of slow abdominal breathing. Then the person confronts the threatening situation, in a careful gradation culminating in the very worst version.

"[For example], one New York City traffic officer confided that she had flown into a rage at a motorist who called her a 'low-life bitch.' So in her exposure therapy that phrase was repeated to her, first in a flat tone, then with increasing emotional intensity, and finally with added obscene gestures. The exposure succeeds when, no matter how obnoxious the repeated phrase, she can stay relaxed - and presumably when back on the street she can calmly write a traffic ticket despite insults."

Daniel Goleman, Social Intelligence, Bantam, Copyright 2006, pp. 78-79.

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