Cognitive flexibility as a target for relapse prevention - Abstract
Recovery involves replacing drinking with more adaptive behavior. Once the more adaptive behavior
becomes habitual, recovery is more resistant to relapse produced by stimuli previously occasioning
drinking. However, until this transition occurs, the new adaptive behavior is easily displaced. This
transition requires cognitive flexibility in order to attend to the stimuli and contingencies associated
with the new behavior. Unfortunately, heavy drinking reduces cognitive flexibility, especially in
females. This reduced cognitive flexibility appears to result from reduced cholinergic activity at α4β2
and α7 nicotinic receptors, particularly those in the hippocampus and anterior cingulate innervated by
cholinergic neurons originating in the medial septum. Restoring cholinergic function may restore
cognitive flexibility during the new learning involved in transitioning from habitual drinking to more
adaptive habits; and thus, speed this transition. Speeding this transition minimizes the most fragile
period of recovery, the early stages before new habits have developed. However, increasing
cholinergic function above an optimal level impairs new learning. Thus, enhancing cholinergic
function may only speed recovery when chronic drinking has reduced cognitive flexibility, perhaps
more so in females. We explore these possibilities using a rat model of recovery we developed. Like
in the real world, in this model high and low levels of drinking are controlled not by changing ethanol
availability, but rather by changing the contingencies governing the availability of alternatives, in this
case food. In the presence of one stimulus, food is costly and drinking predominates. In the presence
of another, food is easily available and little drinking occurs, simulating recovery. After several
consecutive recovery sessions in which rats only encounter low cost food conditions, presenting the
high-cost food stimulus no longer controls responding for ethanol. Instead rats persist at responding
for food, indicating this response has become habitual and control by the high-cost food stimulus has
weakened. We propose examining whether chronic intermittent ethanol exposure slows the
development of recovery, and whether this effect is greater in females. Further, we compare effects of
nicotine to those of epibatidine and PNU-282987, which preferentially activate α4β2 and α7 receptors,
respectively. Finally, we examine effects of delivering nicotine into the hippocampus and cingulate and
compare these to those following administration into the thalamus (not expected to influence cognitive
flexibility). This project explores an innovative target for relapse prevention: medications intended to
speed new habit formation, such as might occur during behavioral therapy. This strategy may
reduce relapse during the early, critical period of recovery, thus improving therapeutic outcomes.