Fig. 2: Autocorrelation window (ACW) in resting and task states.
From: The brain and its time: intrinsic neural timescales are key for input processing
a ACW is defined as the first lag in which the correlation of the signal with itself drops below 50% of the maximum correlation. It is measured from the autocorrelation function. b The ACW, as recorded in MEG22, shows topographical differences between regions during resting and task states. The colormap is in milliseconds and represents the length of ACW. c The brain map represents the uni-transmodal organization of the brain regions. The table schematically shows how ACW changes from resting to task states and also from unimodal to transmodal units in two arbitrary tasks and four sample units. The table is only for illustration purposes. Unimodal and transmodal units refers to either unimodal or transmodal regions in the brain. The numbers 1 and 2 indicate the hierarchical position (1 = lower; 2 = higher) of the respective region/unit. The blue (unimodal) and red (transmodal) intervals represent the width of their respective intrinsic neural timescales (INT) during rest and two different tasks (task 1 and 2). CfR indicates the change from rest to task with either decreasing (downward arrow), increasing (upward arrow), or maintained (horizontal double-sided arrow) width of the regions’ INT during task relative to rest. Though schematically, the differences in the width and rest–task change of the INT during the two tasks shall indicate the flexible and adaptive nature of the timescales as it is supported on both regional22 and cellular24,36,37 levels (see in rest–task overlap and rest–task modulation sections).
