The suppression of scale-free fMRI brain dynamics across three different sources of effort: aging, task novelty and task difficulty.

ABSTRACT: There is growing evidence that fluctuations in brain activity may exhibit scale-free ("fractal") dynamics. Scale-free signals follow a spectral-power curve of the form P(f ) ∝ f(-β), where spectral power decreases in a power-law fashion with increasing frequency. In this study, we demonstrated that fractal scaling of BOLD fMRI signal is consistently suppressed for different sources of cognitive effort. Decreases in the Hurst exponent (H), which quantifies scale-free signal, was related to three different sources of cognitive effort/task engagement: 1) task difficulty, 2) task novelty, and 3) aging effects. These results were consistently observed across multiple datasets and task paradigms. We also demonstrated that estimates of H are robust across a range of time-window sizes. H was also

SUBMITTER: Churchill NW 

PROVIDER: S-EPMC4976369 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature