AGING DIMINISHES THE DIRECT ASSOCIATION BETWEEN BRAIN ACTIVATION AND POSTURAL CONTROL DURING THE N-BACK TASK

Abstract Aging diminishes the control of standing posture, which relies upon the capacity to activate brain regions involved in cognitive-motor function. Our prior work shows that impaired cerebral blood flow (CBF) regulation within the middle cerebral artery (MCA) in response to the N-Back executive function task is linked to worse walking performance in older adults. However, the effects of aging on the relationship between CBF regulation and postural control during the N-Back task is unknown. Sixteen young (27 years) and 15 older participants (76 years) stood upright and completed the N-Back (i.e., control [Identify X, IdX] and an experimental condition [2-Back]) presented on a screen while CBF and postural sway were simultaneously recorded. CBF was recorded using transcranial Doppler. Sway was recorded using a lumbar motion sensor. Elliptical area, root mean square (RMS), distance, velocity, and acceleration were computed. There were no group differences in sway outcomes (p>0.37). Young participants had higher CBF during the IdX and 2-Back compared to older participants (p