Neural substrates mediating context-dependent sensitization to psychostimulants

Abstract

Exposure to a context previously associated with psychostimulants administration can elicit behavioral activation that partially mimics the psychostimulant-induced response or augments psychostimulant-induced motor activity. This interaction between the environment and the behavioral effect of psychostimulants is known as context-dependent sensitization or drug- induced conditioned locomotor activity. Although the neural substrates underlying context-dependent sensitization remain unknown, recent studies have suggested that behavioral sensitization to psychostimulants may be mediated, in part, by a context-conditioned augmentation in glutamate transmission in the projection from the prefrontal cortex and/or amygdala to the nucleus accumbens. In contrast, while dopamine transmission in the nucleus accumbens is clearly involved in the unconditioned response to the acute or repeated administration of psychostimulants, it seems less likely that it mediates the context-dependent effects of cocaine.