Extended Data Fig. 9: Changes in neural responses after stimulus offset are more closely aligned to movement onset than stimulus offset.
From: Transitions in dynamical regime and neural mode during perceptual decisions
a, Relative timing of task events. The offset of the auditory click train stimulus always occurred at the end of the 1.5 s minimum fixation period on every trial. b, The median time of movement onset relative to stimulus offset across trials without a neurally inferred time of commitment (nTc) is 0.192 s. The rightmost bin contains trials for which the movement onset is 0.8 s or more after stimulus offset. c, Principal component analysis (PCA) was performed on peri-event time histograms (PETH’s) aligned to stimulus offset (circles) and averaged across trials without a neurally inferred time of commitment (nTc). Spikes were counted in 10 ms bins, and the PETH was not additionally filtered. Spikes after the animal moved away from the fixation port (i.e., movement onset) were included. For each neuron and each trial condition, the PETH is a 100-element vector. Concatenating across 4605 choice-selective neurons and 4 trial conditions gave a 4605-by-400 matrix. The mean of each row (i.e., the average response of each neuron) was subtracted from the matrix, and PCA was performed on the resulting matrix. Triangles indicate the median time of movement onset. Projections are scaled by the standard deviation explained by each PC. d, PCA performed PETH’s aligned to movement onset offset and averaged across trials without nTc.
