et al., 2007). This hypothesis is wildly different from another prominent perspective that views these DA projections as critical for the attribution of incentive salience, and hence motivational drive, to reward-related stimuli; this theory posits that repeated drug use increases DA sensitivity, leading to increased “wanting” behavior or drug craving (Robinson & Berridge, 2003). According to this perspective, DA is not critical for mediating the hedonic, affective reaction (i.e., “liking” response) to a rewarding stimulus. Instead, such “liking” reactions are coordinated by other neurochemical systems in various small, opioid and cannabinoid-sensitive “hot spots” of positive hedonic affect within portions of the NAc and ventral pallidum (Smith & Berridge, 2005).
