Optimal Trajectories of Brain State Transitions Indicate Motor Function Changes Associated with Aging.

Abstract

Healthy aging is associated with structural and functional changes in sensorimotor systems, leading to a deterioration in motor function. However, most of the previous studies focused on the descriptive measures of alteration, little is known about how structural network facilitate functional dynamics during aging. Based on the structural brain network constructed by diffusion-weighted imaging, we employed recent network control theory to evaluate the control energy necessary to drive the state transition from baseline condition with default mode network (DMN) activation to motor network activation in a large cohort (n = 625; 18-88 years). We found at the whole, the control energy required to activate the motor network declined with aging, in which the motor network contributed most of the control energy. The control energy of nodes within motor network showed both positive and negative age effects, reflecting an aberrant functional integration associated with aging. Interestingly, the control energy of subcortical network most significantly increased with aging, suggesting an altered motor-subcortical circuit, thus requiring more energy for the optimal control. Moreover, the control energy of bilateral putamen showed the largest positive age effect, and this pattern was also supported by the energetic impact of nodes, implying a key role for motor modulation associated with aging. Taken together, our results offer insights of control energy cost necessary for the age-dependent decline in motor task, and provide new clues for brain optimal control of neuromodulation in older adults.