Neural substrates mediating context-dependent sensitization to psychostimulants

Exposure to a context previously associated with psychostimulants administr ation can elicit behavioral activation that partially mimics the psychostim ulant-induced response or augments psychostimulant-induced motor activity. This interaction between the environment and the behavioral effect of psych ostimulants is known as context-dependent sensitization Or drug-induced con ditioned locomotor activity. Although the neural substrates underlying cont ext-dependent sensitization remain unknown, recent studies have suggested t hat behavioral sensitization to psychostimulants may be mediated, in part, by a context-conditioned augmentation in glutamate transmission in the proj ection from the prefrontal cortex and/or amygdala to the nucleus accumbens. In contrast, while dopamine transmission in the nucleus accumbens is clear ly involved in the unconditioned response to the acute or repeated administ ration of psychostimulants, it seems less likely that it mediates the conte xt-dependent effects of cocaine.