To investigate whether changes in gamma power were related to behavior other than reward receipt (or the absence thereof), we identified “turnaround” or “reversal” points in the rats' path (van der Meer and Redish, 2009), where animals deviated from the correct path before returning. Consistent with previous reports of 50 Hz oscillations preceding movement initiation (Masimore et al., 2005), gamma-50 power was transiently increased before the turnaround time (Figure 10A). Gamma-80 power did not show a clearly turnaround-aligned profile, although it was markedly higher before compared to after the turnaround (Figures 10B,C). Turnaround points were taken from the sequence of turns on the central part of the maze only, such that in contrast to movement initiation at the reward sites (Figure 9) they were not preceded by recent reward receipt.
