Extended Data Fig. 4: The time-frequency spectrograms of oscillatory power.
a-f, Time-frequency spectrograms (t-value maps) across 4-150 Hz for initiation state (a, b), maintenance state (c, d), between-state contrast (e, f) in the amygdala/TPJ. Initiation state exhibited increased power, covering broad gamma and high-gamma bands, in both the amygdala (a, from initiation onset and lasted up to 1290 ms, between 24-150 Hz) and TPJ (b, one significant cluster between onset and 1170 ms, 30-150 Hz; another 1380-2000 ms and 41-120 Hz). In addition, we found decreased power in the low frequency band (4-30 Hz) between 940 ms to 1820 ms in the TPJ. Maintenance state was featured with significant power decreases across a broad frequency range (c, amygdala: beginning 110 ms after the maintenance onset, between 10-150 Hz; d, TPJ: from 450 ms after the maintenance onset above 30 Hz and extending the whole maintenance epoch below 30 Hz). A positive cluster was also found in TPJ from 40 ms to 390 ms and between 58-150 Hz, possibly due to the transition effect. Direct comparisons of high-frequency power between initiation and maintenance states revealed significant clusters covering a broad frequency band in the amygdala (e, a cluster extending the whole epoch between 12-150 Hz) and in the TPJ (f, a cluster from epoch onset to 1270 ms at a lower frequency band of 4-24 Hz, another cluster from 310 ms to 2000 ms at the high frequency band of 26-150 Hz). g-j, Time-frequency spectrograms across 4-150 Hz of 2 s around state transition points of reset (g, h) and connection (i, j) for the amygdala/TPJ. During maintenance-to-initiation transition, we observed activity changes from decreased to increased power within gamma and high-gamma bands in the amygdala (g, negative power clusters lasted up to 320 ms before reset points, between 33-150 Hz; a positive power cluster occurring 310 ms after reset points, between 28-134 Hz) and TPJ (h, a negative cluster lasted up to 90 ms before reset points, between 52-150 Hz; a positive power cluster occurring 230 ms after reset points, between 34-146 Hz). In addition, a negative cluster was observed from 650 ms prior to reset points to 910 ms after reset points in across a lower frequency band of 4-54 Hz. During initiation-to-maintenance transition, we observed an opposite pattern of activity, which changed from increased to decreased power within gamma and high-gamma bands in the amygdala (i, positive clusters from 1000 to 140 ms prior to connection points, between 30-100 Hz; a negative cluster from 200 ms to 1000 ms after connection points, between 28-150 Hz) and the TPJ (j, positive clusters from 1000 prior to connection points to 480 ms after connection points, between 49-150 Hz; a negative cluster from 510 ms to 1000 ms after connection points, at high-gamma band of 105-150 Hz). We also found decreased power at the lower frequency band before and after transition in TPJ (a cluster from 1000 prior to connection points to 180 ms after connection points, between 6-46 Hz; another from 530 ms to 2000 ms after connection points, between 4-52 Hz). For display purposes, heat maps were smoothed by convolving power time series with a moving Gaussian window of 250 ms for each frequency bin. Black contours delimit significant clusters after two-sided cluster-based permutation tests (pcorr < 0.05, n = 10000).
