Fig. 2.

Taste ‘liking’ reactions and contrast map of nucleus accumbens hotspots. Positive ‘liking’ reactions to pleasant sweet tastes shared by human newborn, young orangutan, and adult rat (tongue protrusion, left top) and aversive ‘disliking’ reactions to unpleasant bitter tastes (gape, left bottom). Opioid hotspots and coldspots in the nucleus accumbens (medial shell region shown in sagittal view, right). Green The entire medial shell mediates opioid-stimulated increases in ‘wanting’ for food reward. Red Only a cubic-millimeter-sized hedonic hotspot generates increases in ‘liking’ for the same opioid stimulation. Blue A small hedonic ‘coldspot’ suppresses ‘liking’ reactions to sucrose, whereas a larger purple zone suppresses ‘disliking’ reactions to quinine. Reprinted with permission from Smith et al. (2008), based on data from Peciña and Berridge (2005)