Fig. 2
Decision to switch strategies increases theta-band power in left lateral frontopolar cortex. (A) Time–frequency plot of grand average changes in power across all trials (-1 sec before to 0.2 s after response) compared to a baseline period (-1.2 to -1 s before response) averaged over all frontal channels. The dashed box shows the interval with a significant increase in theta-band activity (-0.95 s before to 0.2 s after response; 2-6 Hz) . (B) Topographic distribution of channels with a significant theta power difference: Task vs. baseline. Please note that this plot shows t-values, and the corresponding channel significance (marked with asterisks), averaged over time-window and frequencies for which the significant theta power increase was observed (see A). Thus, frontal channels with the most consistent theta power differences across time and frequencies are shown as significant (N = 16 out of 26). (C) Baseline-corrected changes over time in theta-band power (2-6 Hz) averaged across significant channels and both conditions. The epoch with a significant difference in theta activity as compared to baseline is marked in grey. (D) Time–frequency plot of relative power differences between task conditions (switch vs. maintain) averaged over channels with a significant effect (see E). The dashed box shows the interval with a significant switch effect (-0.25 s before to 0.2 s after response; 2-6 Hz). (E) Topographic distribution of channels with a significant switch effect (asterisks). (F) Changes over time in theta-band power (2-6 Hz) averaged across significant channels (see E). The epoch with a significant difference between the switch vs. maintain condition is marked in grey. (G) Cortical distribution of theta-band (4 Hz) switch effects at the source level (frontal and left view). The dashed circles indicate locations from which the theta-band activity was extracted for the connectivity analyses. (H) Time series of 2-6 Hz activity extracted from left lateral frontopolar cortex (MNI: -32 66 0; see G).
