Fig. 4. Populations of RSC neurons exhibit selective responses spanning trial duration.

(A and B) Imaging of excitatory neuron populations using two-photon microscopy (A) through a cranial window over bilateral RSC (B) during task performance. (C) Example 4-mm cranial window (left; scale bar, 500 μm) and two-photon imaging field (right); scale bar, 50 μm. (D) Example cells exhibiting selective responses for particular contexts (cells 1 to 2) or for both contexts with different dynamics (cell 3). For each cell: top: ΔF/F trace across concatenated correct trials for (context 1, yellow; context 2, blue). Middle: normalized responses across correct trials for context 1 (left) and context 2 (right). Bottom: average activity across correct context 1 (left) and context 2 (right) trials. (E) Average normalized activity of all neurons (n = 10 mice) preferring correct trials in context 1 (top, n = 2634 neurons) and context 2 (bottom, n = 2560 neurons). Averages include only even trials, sorted by peak latency on odd trials. (F) Average normalized activity for all responsive neurons (n = 5194 neurons from 10 mice) for the preferred (left) and nonpreferred (right) context. Averages include only even trials, sorted by peak latency on odd trials. (G) Fraction of neurons with peak activity at each trial time (mean ± 97.5% CIs). (H) Average peak response magnitude of all neurons as a function of trial time (mean ± SEM). (I) Neuronal activity trajectories for correct trials in both contexts obtained by targeted dimensionality reduction. Trajectories are initially similar but diverge as a result of the context and motor decision, followed by parallel displacement in the outcome dimension for both trajectories (s, trial start; d, decision point; e, trial end). a.u., arbitrary units. (J) Distance between trajectories described by neuronal activity in correct trials for both contexts (mean ± bootstrap-estimated SEM). Arrowheads indicate trial start (black), decision point (gray), and trial end (cyan).