Figure 5. The bias of reward responsive VTA unit activity towards the replay of reward locations is greater for centrifugal than centripetal replay.

(A1,2) Bayesian reconstruction of run position and run direction on the linear track (500 ms time bins). Outbound refers to run direction from 0 to 200 cm. (A3) Position confusion plot for this recording session, using alternating 1 s epochs for training and testing the reconstruction algorithm. (A4) Run direction confusion plot. (B) Centrifugal, forward replay event occurring while the rat paused at the far reward site (190 cm; black circle indicates the rat’s position). (B1) Position reconstruction (25 ms time bins). (B2) direction reconstruction). (B3) The associated hippocampal multiunit activity. (C) Centripetal, forward replay event occurring while the rat paused at the far reward site. (C1) Position reconstruction. (C2) Direction reconstruction. (C3) Associated hippocampal multiunit activity. (D) Across centrifugal replay time bins, RR unit spikes preferentially coordinated with replay of reward locations compared to centrifugal replay content in general (p=0.014, chi=6.0, Chi-square test) and compared to nonRR units at centrifugal replay (p=0.05, nonparametric permutation test). Error bars represent s.d. (E) Across centripetal replay time bins, RR unit spikes showed no increase in coordination with replay of reward locations compared to centripetal replay content in general (p=0.5, chi=0.5, Chi-square test). Error bars represent s.d.

DOI: http://dx.doi.org/10.7554/eLife.05360.010

Figure 5—figure supplement 1. Centrifugal and centripetal replayed locations associated with RR unit activity on the SWM task and the linear track.

(A) On the SWM task, the distribution of centrifugal replayed locations (green) is less concentrated at reward sites (marked by vertical lines) than the distribution of RR unit-associated centrifugal replayed locations (blue). See Figure 5 for statistics. Maze segments were aggregated by apposing them in the direction of run in the choice direction: from force reward sites (R3, R4) to force point (fp) to choice point (cp) to choice reward sites (R1, R2). Spatial bins 1–10 show the average of the force arms of the task (arms 3 and 4), spatial bins 11–20 show the central arm, and spatial bins 21–30 show the average of the choice arms (arms 1 and 2). (B) The distribution of centripetal replayed locations (green) on the SWM task is similar to the distribution of RR unit-associated centripetal replayed locations (blue). (C) On the linear track, the distributions of centrifugal replayed locations (green) and RR unit-associated centrifugal replayed locations (blue) are similar. (D) On the linear track, the distribution of centripetal replayed locations (green) and the distribution of RR unit-associated centripetal replayed locations (blue) are also similar.

DOI: http://dx.doi.org/10.7554/eLife.05360.011