2. State-trait dynamics of the human brain reflect individual behavior and life functions

COEX 

Spontaneous fluctuations of brain activity are embedded in time and space, exhibiting rich spatial-temporal information that varies within (state) and between (trait) individuals. The joint properties of state-trait resting-state fMRI signal variation and the mapping of these neural variation to behavior remain poorly understood. To fill this gap, we quantify moment-to-moment changes in brain-wide co-activation patterns (CAPs) derived from resting-state fMRI in healthy young adults (n=337). We demonstrate spatiotemporal features of CAP dynamics that are reproducible at the individual level. We found that distinct parameters of CAP temporal characteristics, such as occupancy and persistence, can be studied together and represented as either state or trait features. A joint analysis of state-trait neural variations and feature reduction reveal general motifs of individual differences, encompassing state-specific and general neural features that exhibit day-to-day variability. The principal neural variations co-vary with the principal variations of 262 behavioral phenotypes. Specifically, people who showed longer time spent in a given CAP, longer persistent periods within a CAP, as well as higher variation in transitioning between all CAPs, also showed higher cognitive function, improved emotion regulation, and lower alcohol and substance use. Critically, person-specific probability of occupying a particular CAP was highly reproducible and associated with both neural and behavioral features. This highlights the importance of studying CAP-derived measures as a neural marker that may be altered as a function of mental health symptoms and may change developmentally. Collectively, these results show a reproducible pattern of neural co-activation dynamics in humans, which capture both within- and between-subject variance that in turn maps onto functional life outcomes across people.