Moment-to-moment brain signal variability: A next frontier in human brain mapping?

Neuroscientists have long observed that brain activity is naturally variable from moment-to-moment, but neuroimaging research has largely ignored the potential importance of this phenomenon. An emerging research focus on within-person brain signal variability is providing novel insights, and offering highly predictive, complementary, and even orthogonal views of brain function in relation to human lifespan development, cognitive performance, and various clinical conditions. As a result, brain signal variability is evolving as a bona fide signal of interest, and should no longer be dismissed as meaningless noise when mapping the human brain.

► Neuroimaging is often rooted in the pursuit of central tendency when examining brain activity within and across persons. ► However, broad neuroscientific evidence supports the inherent fluctuating state of the brain. ► Measures of brain signal variability demonstrate results not attainable by traditional methods. ► Such measures reveal novel insights regarding cognition, the lifespan, brain injury, and disease. ► Signal variability should represent a next frontier in human brain mapping.