Figure 4.

Functional dose–response VP maps of DAMGO effects on hedonic “liking” and eating behavior. A, Location of VP maps in horizontal and sagittal sections (Paxinos and Watson, 1998) (horizontal insert overlaid with enkephalin stain). R, Right; L, left. B, DAMGO effects on sucrose “liking.” Color function maps shows change in hedonic “liking” reactions elicited by sucrose taste after each dose of DAMGO (0.01, 0.1, 0.25 μg) compared with vehicle (percentage change from vehicle, 100% at same sites). Symbols as in Figures 2 and 3. The bottom bar graph represents number of positive hedonic “liking” reactions after DAMGO or vehicle in anterior and posterior halves of VP (*p < 0.05; **p < 0.01). C, DAMGO-evoked eating behavior. Color maps showe ating durations evoked by each dose of DAMGO (0.01, 0.1, 0.25 μg) compared with vehicle (absolute change). Bar graph represents eating total duration in anterior and posterior VP halves after vehicle or each DAMGO dose. Error bars represent SEM.