Pronounced feeding can be elicited by injections of the GABA(A) agonist muscimol into the medial shell region of the nucleus accumbens (AcbSh). This region of AcbSh has been shown to project to both the lateral hypothalamus (LH) and the medial ventral pallidum (VPm). The current study examined the effects of unilateral LH or VPm lesions on the ingestive responses induced by injections of muscimol into the AcbSh on either the same or the opposite side of the brain. We found that lesions of either of these structures drastically attenuated feeding induced from the ipsilateral, as compared to the contralateral, AcbSh. The "ipsilateral/contralateral disruption design" employed here virtually rules out the possibility that the suppressive effects of the lesions were nonspecific and suggests that the VPm and LH play essential roles in mediating the ingestive effects of inactivation of the AcbSh.
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