Figure 1. Experimental apparatus and task.

(A) Illustration of the figure 8 maze. The target feeders are elevated on some trials to impart physical effort. (B) Schematic illustration of the task. The reward volume is indicated by the number of drop symbols, and the climbing effort by the black trace of feeder platform height. The sequence of trial blocks (background shading) is repeated after drug injection. (C) Representative sample of a histological section showing the endpoints of electrodes (arrows). The inset show the relative position of the section aligned to a standard rat brain atlas (Paxinos and Watson, 2014).