Summary
A bioRxiv preprint analysing fMRI data from 1,712 people reports that task-related changes in brain activity timescales vary across cortical regions, track cognitive performance and follow a two-stage pattern during youth. The findings link these changes to cortical features associated with neural plasticity, but do not establish a causal mechanism.
A bioRxiv preprint reports that the brain’s characteristic activity timescales change when people perform cognitively demanding tasks, and that the pattern of change develops across youth. The analysis covered four independent fMRI datasets with 1,712 participants aged 8–64. The authors found that task-related timescale changes were strongest in association cortex, tracked cognitive performance, and followed a two-stage pattern during development.
How brain timescales change during tasks
Intrinsic neural timescales describe how far apart in time activity in a brain region remains related. At rest, these timescales vary across the cortex: they tend to be faster in sensorimotor regions and slower in association areas, which support more complex information processing. The researchers call the rest-to-task changes in these timescales “timescale deflections.”
Across all four datasets, timescales became shorter under cognitive load. The reduction was greatest in association cortex, partly narrowing the difference between the faster and slower ends of the resting-state hierarchy. This suggests that the cortical pattern of temporal integration is not fixed: it shifts with task demands. The size of those shifts also varied between individuals and was organised along the sensorimotor-to-association axis.
The study used fMRI, which estimates brain activity indirectly through changes in blood oxygenation rather than recording individual neurons. The results therefore describe patterns in fMRI-derived activity timescales.
A two-stage pattern across youth
Among young participants, the authors report a general reduction in timescale deflections through childhood, followed from mid-adolescence by an expansion concentrated in association cortex. Individual differences in deflections tracked cognitive performance in both youth and adults. These relationships connect the measured flexibility with behaviour, though they do not show that changing timescales causes differences in performance.
The timing of the developmental pattern aligned with cortical gradients of inhibitory gene expression and intracortical myelin content. Both features have been implicated in the opening and closing of critical periods—phases when the brain may be especially responsive to experience. This alignment offers a possible developmental context for the findings, but the abstract does not establish that either feature drives timescale changes.
The work is a preprint posted on bioRxiv and has not yet undergone peer review. Its findings offer a way to study how the brain’s temporal organisation varies with cognitive demands and matures across adolescence; the detailed task and analysis methods are needed to assess how the reported measures were defined and compared.