The temporal autocorrelation function indexes the timescale over which prior states of the dynamics predict future states (see Experimental Procedures). We calculated autocorrelation width (ACW) values by measuring the full-width-at-half-maximum of the temporal autocorrelation function of each electrode, and found that electrodes with longer TRWs had greater autocorrelation width, regardless of whether GSK1349572 ACW was measured during the intact clip (r = 0.33, p < 0.01; Figure 6F),
the coarse-scrambled clip (r = 0.25, p < 0.05), or the fine-scrambled clip (r = 0.21, p = 0.07; Figure 6G). The LowFq and ACW measures are connected via the Wiener-Khinchin theorem, but this relationship is not always simple. In the current data, we found that the ACW and LowFq parameters were robustly positively correlated (Figure S2), and the ACW analysis confirmed the finding that power fluctuations occurred more slowly on average in regions that accumulate information over longer timescales. Together, the results above identify features of neural dynamics (LowFq and ACW) that are associated on a site-by-site
basis with the processing of temporal information in a stimulus (TRW). A similar relationship between dynamic timescale and the TRW index was observed in the power fluctuations of the θ, α, low β, and γ bands, although the smaller number of reliable electrodes in these bands diminished the statistical power (Figure S3). In addition, a comparable relationship between LowFq and the TRW parameter RG7204 cost was observed when the TRW index was defined as rCOARSE − rFINE rather than as rINFACT − rFINE ( Figure S4). To rule out the possibility that the relationship between the timescale of neural dynamics and the TRW index was driven by temporal statistics of the stimulus (which differ across conditions; Figure S5), we measured LowFq and ACW values during 30 s fixation periods that preceded each stimulus (see Experimental Procedures). Aldehyde dehydrogenase The fixation-period ACW parameter showed a
robust correspondence with the TRW index (r = 0.29, p = 0.01; Figure 6H); this correlation between ACW and TRW values was as strong as those in the movie-stimulated data. Estimates of LowFq parameter during fixation were less precise, because of shorter data windows and fewer overall data points, but we nonetheless observed a weak correlation across electrodes between fixation-period LowFq and the TRW index computed from the movie-viewing data (r = 0.19, p = 0.10; Figure 6E). In addition, both LowFq and ACW values in each electrode were highly correlated between states of fixation and movie viewing (Figure S6). Both short TRW and long TRW regions exhibited increased values of LowFq for the intact stimulus relative to the fine-scrambled stimulus (Figure 6B), which indicated that the dynamics of the stimulus can alter the timescales of the neural responses.