Fig. 7

Match–nonmatch difference. a Mean absolute firing rate difference during the sample (second stimulus) presentation period for a stimulus at the best location of each neuron, when it appears as a match relative to when it appears as a nonmatch. Error bars represent the standard error of the mean calculated across all neurons, before and after training. Only neurons that were tested with the Match-Nonmatch presentation were used in this analysis (n = 3132). Stars indicate significant differences (p < 0.05) in 1-way ANOVA comparing responses between areas prior to training; and 2-way ANOVA and post-hoc Tukey test comparing responses in the same area before and after training. Superimposed circles represent means calculated separately for each individual monkey. Unequal sample sizes were obtained from each monkey therefore bars do not correspond to the mean of the individual monkey values. b The same match/nonmatch difference for the same population of neurons is expressed as dʹ. c Match–nonmatch discharge rate difference plotted along the AP axis of the dorsal prefrontal cortex before training. Each point represents the value of one neuron, prior to training. Line represents linear regression. d. Match–nonmatch discharge rate difference in the dorsal prefrontal cortex, after training. e, f Each point represents the mean value of the |M–NM| quantity calculated in a region, from one monkey, for the dorsal prefrontal cortex. The point is plotted in the AP location corresponding to the mean value of the recordings. Line represents linear regression through these monkey-derived means. g, h Match–nonmatch discharge rate difference in the ventral prefrontal cortex, before and after training. i, j Data from individual monkeys plotted as in (d, e) for the ventral prefrontal cortex