Relatively little is known about the behavioral correlates of ventral striatal LFPs in healthy subjects. Whereas ventral striatal LFP oscillations in vivo (in rats) have been reported previously, these have generally not been related to task, behavioral, and reward parameters (Berke et al., 2004; Hunt et al., 2006; Kasanetz et al., 2002; Leung and Yim, 1993; but see Gruber et al., 2009 for a recent exception). Recording from a range of sites in striatum, Berke et al. (2004) reported a gradient in gamma power along the dorsolateral-ventromedial axis, with increasing power in the ventromedial aspect. Masimore et al. (2005) found transient 50 Hz events preceding movement, and noted a similar gradient to that reported by Berke et al. (Masimore, 2008). This suggests that 50 Hz gamma oscillations may be particularly important in ventral striatum. Interestingly, Kalenscher et al. (2008) found reward-related gamma oscillations in ventral striatum, but in contrast to Masimore et al. (2005), only a weak relationship to movement parameters. While these results do not imply that gamma oscillations in ventral striatum are locally generated, preliminary reports have found
