13 April 2011

Drink to remember (subconsciously, at least)

by Kate Melville

According to researcher Hitoshi Morikawa, repeated ethanol exposure enhances synaptic plasticity in the brain, providing further evidence toward an emerging scientific consensus that drug and alcohol addiction is fundamentally a learning and memory disorder.

"Drinking alcohol primes certain areas of our brain to learn and remember better," contends Morikawa, from The University of Texas at Austin. "Usually, when we talk about learning and memory, we're talking about conscious memory. Alcohol diminishes our ability to hold on to pieces of information like your colleague's name or where you parked your car this morning. But our subconscious is learning and remembering too, and alcohol may actually increase our capacity to learn, or 'conditionability,' at that level."

Writing about his findings in the Journal of Neuroscience, Morikawa explains that when we drink alcohol (or shoot up heroin, or snort cocaine), our subconscious mind is learning to consume more. We become more receptive to forming subconscious memories and habits with respect to food, music - even people and social situations.

Alcoholics aren't addicted to the experience of pleasure or relief they get from drinking, Morikawa says, they're addicted to the environmental and behavioral cues that are reinforced when alcohol triggers the release of dopamine in the brain. "People commonly think of dopamine as a happy transmitter, or a pleasure transmitter, but more accurately it's a learning transmitter. It strengthens those synapses that are active when dopamine is released."

Alcohol, he adds, is an enabler. It hijacks the dopaminergic system, and it tells our brain that what we're doing at that moment is rewarding (and thus worth repeating). Among the things we learn is that drinking alcohol is rewarding. We also learn that going to the bar, chatting with friends, eating certain foods and listening to certain kinds of music are rewarding. The more often we do these things while drinking - and the more dopamine that gets released - the more "potentiated" the various synapses become and the more we crave the set of experiences and associations that orbit around the alcohol use.

Morikawa's long-term hope is that by understanding the neurobiological underpinnings of addiction better, he can develop anti-addiction drugs that would weaken, rather than strengthen, the key synapses. "We're talking about de-wiring things," he says. "It's kind of scary because it has the potential to be a mind controlling substance. Our goal, though, is to reverse the mind controlling aspects of addictive drugs."

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Source: University of Texas at Austin