Fig. 4.

Previous reward outcome impacts current reward firing. a, c Normalized activity of all neurons in NAc (a) and VP (c) on sucrose (orange) and maltodextrin (pink) trials of each reward, separated by reward outcome on preceding trial; darker lines indicate that sucrose was the prior trial’s reward. Asterisk indicates a significant main effect of previous reward on normalized firing rate in VP (F(1,1724) = 10.1, p = 0.022) for the epoch bounded by the vertical blue lines. b, d Normalized reward-related activity of every individual neuron in NAc (b) and VP (d) on trials with each combination of previous and current reward. e Mean coefficient weights for the impact of the current and previous 6 trials on normalized firing rate in the same epoch as (a, c) for each neuron in NAc (purple), VP (green), and corresponding data for each neuron with the outcomes shuffled (black) for each region. Error bars are SEM. Asterisks are p < 0.05 for Tukey tests comparing VP coefficients to shuffled data, corrected for multiple comparisons. f Proportion of the neural populations in VP (green), NAc (purple), and corresponding shuffled neurons (black) with significant coefficients for each of the relative trials. Asterisks represent p < 0.05 for chi-square tests on both the distribution of neurons across all four conditions (true and shuffled data from each region) and across the true data from each region