Understanding variability in the BOLD signal and why it matters for aging

Abstract

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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Acknowledgments

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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Correspondence to Cheryl L. Grady.

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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

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Keyword

  • fMRI
  • BOLD signal
  • Variability
  • Aging
  • Cognition