Figure 3. Outcome selectivity in ventral striatum of sham-lesioned rats.

A,B. Shown are population averages of normalized firing rate across the time of the trial, aligned to the end of the odor period, for all odor-responsive units (n=66). Activity is averaged by preferred (left panel) and anti-preferred (right panel) directions, and by the specific reward available at the end of the trial (in different colors). Preferred direction was defined for each unit by the direction with the highest average activity during the epoch from odor initiation to port withdrawal (in gray shading). Only correct forced-choice trials in the latter part of the block (after the first twenty correct trials) are included in the averages. Black bars indicate bins with a significant effect of number of drops of reward, by ANOVA on a sliding average of five bins across neurons. There were no bins with a significant effect of reward flavor.

B. Shown are number-selectivity indices during the odor epoch for each neuron in the population, separately for the preferred (left panels) and anti-preferred (right panels) directions. Insets show indices early in blocks immediately following number shifts. Number-selectivity index was defined as the difference in normalized firing rate between conditions with the large reward and those with the small reward. Dark-coded units are those in which this difference was significant across trials.

**, p<0.01, both the indices of the population and the proportion of significant neurons were significantly shifted to the right.

C. Shown are flavor-selectivity indices with the same conventions as in B., with insets showing the indices in the trials immediately after flavor shifts. Indices were not shifted towards either flavor (except early in the preferred direction), but had a larger magnitude (absolute value) and were more likely to be significant, in the preferred direction compared to the anti-preferred, late in blocks.