Fig. 2.

Group average STNr LFP power changes over time. Power change across (A and C) the low effort (SRE levels < 5) and (B and D) high effort (SRE ≥ 5) ranges at different frequencies. There were power increases in the theta (4–7 Hz) and alpha (8–12 Hz) bands, and a decrease in both low (13–22 Hz) and high beta (23–30 Hz) band just prior to and following response onset. There was a prominent increase in gamma (55–90 Hz) power with response onset that was greater over the high effort range. Activities in a broad high frequency band (101–375 Hz) also increased with response onset, more prominently in high effort trials, although the relative increase was much smaller than the activity in the gamma band. LFP power was normalized to the period between 1.5 s and 0.5 s before the cue and re-aligned to movement onset before averaging. Shading represents the standard error.