Figure 3.

(A) Firing rates for all cells during ABCD, sorted for CA3 and CA1 by condition that elicited maximal firing rate. Z-axis is the trial averaged z-normalized firing rate. X-axis sorts trial types by Context, Position, Valence, and Item. Strong item coding is reflected in different firing rates among items within a position. (B) Simultaneously recorded cell ensembles for seven trials within an example session. Each histogram is the population vector composed of z-scored (range −1.95 to 7.02 SD) firing rates during one trial identified by Context (Con), Position (Pos), Item (A,B,C,D) and reward valence (+,−). (C) An example correlation matrix from one session showing correlation coefficients by color code (right scale). (D) The mean correlation coefficients (+SEM) for within- and between-condition item sampling events for each task dimension (see Table 1). For all dimensions except set, the correlation coefficients are higher for within-condition trials than between. IVSPC as defined in Table 1. See Figure S2 for individual rat data. (E) A dendrogram showing that ensembles of the same valence in the same position are most similar, followed by ensembles associated with items of opposing valence within the same position. Positions within the same context were also coded more similarly than positions in the opposing context. See also Figures S1-S3.