addiction’s neural insult, the catch-22

how does the brain adapt to changes in environment? ask a neuroscientist, and the answer may very well be - if the neuroscientist is a particularly honest one - "i have no idea."

well, that’s not quite fair. we know it has something to do with change in a neuron’s dendritic branches, the arms that grab on to neurotransmitters, allowing messages to pass from one neuron to the next. this theory is young. it seems to hold water, though, so we’re running with it.

so what does this have to do with addiction, pray tell? well, a few years ago researchers found that stimulants in cocaine, speed, and even cigarettes do quite a bit of this dendritic modification. that seemed evident, even innocuous, until researchers hit us with another theory: the capacity for this change in neurons (i.e., structural plasticity) may be finite. there is only so much a neuron can adapt, and stimulants are using up some of that precious capacity.

a recent study published in behavioral neuroscience partially confirms this fear. the study, done on rats using nicotine, notes that although we attribute the ill effects of addiction to brain damage,

at least some of the psychological effects associated with stimulant use may be related to subsequent limits on structural plasticity rather than frank damage.

in sum, drugs may diminish the ability to adapt to new circumstances and experiences. unfortunately, that ability is the one thing a recovering addict needs most.

source: hamilton, d. a. and kolb, b. differential effects of nicotine and complex housing on subsequent experience-dependent structural plasticity in the nucleus accumbens. behavioral neuroscience vol 119, no. 2

Labels: neuroscience