Recent work in neuroscience supports the idea that variability in brain function is necessary for optimal brain responsivity to a changing environment. In this review, we discuss a series of functional magnetic resonance imaging (fMRI) studies in younger and older adults to assess age-related differences in variability of the fMRI signal. This work shows that moment-to-moment brain signal variability represents an important “signal” within what is typically considered measurement-related “noise” in fMRI. This accumulation of evidence suggests that moving beyond the mean will provide a complementary window into aging-related neural processes.
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We also found a similar pattern of relations between positive signal variability and cognitive performance when we analyzed the two age groups separately.
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This work was supported by the Canadian Institutes of Health Research (grant #MOP14036). C.L.G. also is supported by the Canada Research Chairs program, the Ontario Research Fund, and the Canadian Foundation for Innovation.
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Grady, C.L., Garrett, D.D. Understanding variability in the BOLD signal and why it matters for aging. Brain Imaging and Behavior 8, 274–283 (2014). https://doi.org/10.1007/s11682-013-9253-0
- BOLD signal