Extended Data Fig. 5: Detailed analysis of lSC activity modulation after iSPN stimulation.

a. Example units that were not significantly modulated by stimulation. Peri-stimulus histogram showing no stimulation trials (left) and stimulation trials (right, light blue=laser on) during left- (blue) and right- (red) cued trials. b. Changes in firing rate (similar as in Fig.2i) but with data separated for contraversive preferring, ipsiversive preferring and no-preference units during left-cued trials (left column) and right-cued trials (right column) in right lSC (top row) and left lSC (bottom row). Only contraversive preferring neurons were significant modulated by iSPN activation in both left and right trials in left and right lSC (p-values for two-tailed t-test in the 100ms window after stimulation onset are shown). c. Changes in firing rate induced by stimulation (Δspikes s⁻¹ = activity in stim trials – activity in no stim trials) for units in the right (top) and left (bottom) lSC for stimulation trials but including only data from the subset of sessions that had both incorrect and miss outcomes (incorrect: blue, miss: grey; Methods) and separating trials based on outcome. Changes in firing rates in right SC did not differ (n = 129, P = 0.40, two-tailed t-test) but changes were larger in left SC during incorrect licking vs miss trials (n = 64, P = 0.01, two-tailed t-test). Firing rate are show as mean ± s.e.m. across units. d. Fractions of neurons that were excited, inhibited, or unchanged by optogenetic stimulation in left- and right-cued trials for contraversive-lick-preferring (left), ipsiversive-lick-preferring (middle), and untuned (no pref, right) groups (similar analysis as Fig.2g) recorded in the left or right SC. e. iSPN activation during the ITI (e-f). Example units recorded in the left SC (left panel) and right SC (right panel). Peri-stimulus histogram shows trials during which the stimulation did (red/blue) or did not (grey) induce licking. Firing rates are given as mean ± s.e.m across trials. f. Average changes in firing rate after stimulation (Δspikes s⁻¹) in left SC (left panel) and right SC (right panel) grouped by behavioral outcome (red/blue=lick; grey=no lick). Firing rates shown as mean ± s.e.m across units (left SC: n = 225; right SC: n = 201). g. Average firing rates during the 100 ms stimulation window for stimulation trials without (y-axis) vs. with (x-axis) licking. Each dot represents a single unit. P-values show significance of modulation (two-tailed t-test).