LTM−WM: effects in the beta band.

<p>A) Time-frequency representation of the sensors in the significant cluster and topographical representations of beta band activity when comparing the rehearsal interval of LTM encoding and WM maintenance trials. A decrease in beta power (15–27 Hz) is shown at sensors marked in the topographical plot. The topography of the z-values is shown in the most right panel. B,C) The sources of the decrease of beta power when comparing LTM encoding to WM maintenance. The sources of this effect are widespread but include LIFG and left insula. Z-values of the statistical comparison (B) and power values between half of the maximum to the maximum value are shown (C). D) The average beta power from sensors in the significant cluster shows the time-course of the effect for all conditions separately during word presentation and rehearsal. E) There was a negative correlation between beta power (LTM−WM/LTM+WM) and performance for each subject on the LTM retrieval test (r = −0.52, p = 0.011, N = 23).