Figure 4.

STN neuronal firing increases are primarily speech-locked. A, An example of an A-sort single unit whose firing rate increase is locked to production onset. Spike raster (top) and mean firing rate (bottom) aligned to cue presentation. Significant spike bursts are shaded for each trial according to their PS index. Trials are sorted by speech production latency; speech production onset for each trial is indicated in green. B, The time interval between cue presentation and burst onset (neuronal response latency) and between burst onset and production onset (neuronal response to production interval) for each trial is correlated against production latency. C, Summary of correlation analyses for all unit recordings with increase-type responses, showing 12/29 responses locked to production onset (red circles), 2/29 responses locked to cue presentation (blue circles), and 2/29 responses locked to both cue and production onset (black circles). Open circles in C and indicate B-sorts.