Figure 1.

a, Sequence of task events. Upon house-light illumination, rats nose poked into a central odor port. After 500 ms, one of three odors was presented. One odor signaled forced-choice left, another odor signaled forced-choice right, and a third odor signaled free choice. After the 500 ms presentation of the odor, rats had 3 s to respond to one of the fluid wells. After fluid well entry the rats were required to wait in the well until reward was delivered. The size of the reward (large = 2 boli or small = 1 bolus) associated with left and right fluid wells varied from block to block. Trial blocks consisted of at least 60 rewarded trials. See Materials and Methods for more detail. b–d, The height of each bar indicates the percentage choice on free-choice trials (b), and the percentage correct (c) and reaction time (d; odor offset to odor port exit) on large-reward (dark gray) and small-reward (light gray) trials for control and NVHL. e, Latency to nose poke after onset of house lights during the first and last five trials in each block for NVHL (thin) and control (thick) rats. Analyzed behavior comes from recording sessions with reward-response cells from which neural analysis was performed. Asterisks indicate planned comparisons revealing statistically significant differences (t test, p < 0.05). Error bars indicate SEs. #, Indicates main effect of group (NVHL vs control) in the ANOVA (p < 0.05).