Fig. 3.

Whole-brain cofluctuation amplitude synchronizes during passive movie watching. We compared cofluctuation time series during resting state and movie watching. For both conditions, we computed cofluctuation time series for 29 subjects. We show those time series in A (movie) and C (rest). We find that when subjects watch movies, their cofluctuation time series are synchronous, presumably due to the shared audiovisual stimulus. At rest, cofluctuation time series are asynchronous. We demonstrate this synchrony by computing the intersubject correlation matrix of subjects’ cofluctuation time series. We show matrices for movie watching and rest in B and D, respectively. By comparing the elements of these matrices, we demonstrate statistically that movie watching leads to increased intersubject correlations. We show the distributions in E. We find, however, that the overall amplitude of fluctuations (RSS) is not statistically different from one condition to the other (F). To further contrast these two conditions, we repeated the analysis from High-Amplitude Frames Are Driven by Fluctuations of Task-Positive/Task-Negative Mode of Brain Activity to identify modes of brain activity that underpin high-amplitude frames. We find that the resting mode recapitulates the topographic distribution reported in the previous section (H), emphasizing a task-positive/task-negative division. During movie watching, however, the mode of activity emphasizes contributions of visual and dorsal attention networks (G). In I–K, we compare rest and movie-watching modes of activity more directly. I depicts the region-wise differences in modes, J groups those differences by system, and K presents them as a scatterplot, highlighting differences associated with visual, dorsal attention, and salience/ventral attention networks.