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. 2020 Jun 10;9:e57215. doi: 10.7554/eLife.57215

Figure 1. Reactive and Proactive Behavioral Inhibition.

(A) Left, operant box configuration; right, event sequence for Go and Stop trials. RT, reaction time; MT, movement time; SSD, stop-signal delay; Reward, delivery of a sugar pellet to the food port. (B) Left, distributions of Go and Failed-Stop RTs (on Maybe-Stop trials; shading, S.E.M. across n = 63 sessions). Failed-Stop RTs are similar to the faster part of the Go RT distribution, consistent with the ‘race’ model in which a relatively-fast Go process produces failures to stop. The tail of the Failed-Stop distribution (RT >500 ms) is presumed to reflect trials for which rats successfully responded to the Stop cue, but then failed to maintain holding until reward delivery (see Leventhal et al., 2012; Schmidt et al., 2013; Mayse et al., 2014). Right, proportions of failed and successful Stop trials after Contra and Ipsi Go cues. Error bars, S.E.M. across n = 63 sessions. (C) Trial start location indicates stop probabilities (locations counterbalanced across rats). In this example configuration recording from left GP, starting from the middle hole indicates the Maybe-stop Contra condition: Go cues instructing rightward movements might be followed by a Stop cue, but Go cues instructing leftward movements will not. (D) Proactive inhibition causes selective RT slowing for the Maybe-Stop direction (two-tail Wilcoxon signed rank tests on median RT for each session: contra cues in Maybe-Stop-contra versus No-Stop, z = 7.7, p=1.15 × 10−14; ipsi cues in Maybe-Stop-contra versus No-Stop, p=0.32). Additionally, under selective proactive inhibition rats were more likely to fail to respond quickly enough (RT limit errors; Wilcoxon signed rank tests, z = 7.2, p=5.41 × 10−13) and to select the wrong choice (uncued action direction; Wilcoxon signed rank tests, z = 7.0, p=2.59 × 10−12). Error bars, S.E.M. across n = 63 sessions. Only trials without a Stop cue are included here. RT limit error = Nose remained in Center port for >800 ms after Go cue onset; MT limit error = movement time between Center Out and Side port entry >500 ms.

Figure 1.

Figure 1—figure supplement 1. Behavioral data for all sessions and for each individual animal.

Figure 1—figure supplement 1.

(A) Proactive slowing of RT is visible in aggregate across all recorded sessions (n = 251 sessions, from six rats), in both left and right directions. Shading indicates SEM across rats. (B) Cumulative density plots of RT for all sessions included in electrophysiology data analysis for each rat, in the same format as Figure 1. Left plots, comparison of Go RT and Stop-fail RT; right plots, selective proactive inhibition for movements contraversive to the recorded neurons.