Fig. 3.

Hedonic liking for UCS was increased by opioid stimulation of the NAc hotspot but not by dopamine stimulation. (A) DAMGO microinjection in the NAc increased VP firing to the intraoral UCS sucrose taste (red line; mean firing rate over baseline ± SEM band as in Fig. 2) compared with after vehicle microinjection (gray line). Amphetamine microinjection in the NAc failed to enhance VP firing to the UCS (green line). x axis is as it is in Fig. 2. (B) Behavioral confirmation that DAMGO uniquely enhanced hedonic impact of sucrose was seen in increased orofacial liking reactions to the sucrose taste after opioid stimulation of the NAc but never after dopamine stimulation.