Cocaine dependence remains a serious problem in the US today and in spite of two decades of intense research, efficacious pharmacotherapeutic treatments have not been identified. Cocaine-associated environmental cues can elicit drug craving and exposure to cocaine-related cues is likely to be involved in relapse. Emerging data supports the role of glutamate in extinction of associative learning in animal models of rear-conditioning and clinical studies of exposure treatment for anxiety disorders. A recent study demonstrated DCS acceleration of cocaine-induced conditioned place preference in rats (Botreau et al., 2006). Exploration of DCS in facilitating extinction of response to drug-related cues in humans is needed. The proposed study will extend these innovative and promising findings from the basic science arena and anxiety disorders field in a proof of concept investigation of DCS facilitation of extinction of response to cocaine-related cues in a human laboratory paradigm.