Figure 4.

Neural activity in ABL of aged animals was not increased in response to unexpected reward delivery and omission. a, b, Heat plots showing average raw (a) and normalized (b) activity over all ABL neurons from aged animals (n = 72) that showed a significant effect of delay or size in the ANOVA during the 1 s after reward delivery. Contingencies are the same as in Figure 3a. Data normalized by dividing firing rate by the maximal firing during the trial. c–e, Distribution of indices representing the difference in firing in individual neurons to reward delivery (c) or reward omission (e) early versus late in the relevant trial blocks. Correlation between indices shown in c and e is shown in d. Filled bars (c, e) and dots (d) indicate the values of neurons that showed a significant main effect (p < 0.05) of learning (early vs late) with no interaction in the two-factor ANOVA described in the text.