Figure 1.

(a, b) Timelines illustrating order of behavioral training and testing in the cocaine and food self-administration experiments, respectively. As indicated in the Materials and Methods section, not all animals completed all steps. (c) Active and inactive lever presses and infusions during cocaine self-administration. (d) Active and inactive lever presses and number of food pellets during food self-administration. (e) Diagram showing microinjection tracks terminating in the RMTg for both the cocaine- and food-seeking groups. Figures adapted from Paxinos and Watson (2007) and A/P coordinates (in mm) are given relative to Bregma. Owing to the lack of clear structural boundaries for the RMTg, inclusion of data from animals was based on a conservative analysis and thus only needle tracks confirmed to be within the RMTg were included. In all cases, there was little evidence of tissue damage at the injection sites.