The purpose of this study was to investigate the aging effects on the motor related regions of the brain, especially basal ganglia-thalamo-motor loop. Ten young healthy subjects and 10 aged healthy subjects participated in this study. We performed the functional magnetic resonance image (fMRI) mapping of sequential left-hand finger movements at five different paces under self-initiated (SI) and externally triggered (ET) conditions, respectively. fMRI signal change was extracted at the activated regions within the basal ganglia-thalamo-motor loop. Then, we computed interregional correlation, constructed correlation matrix and calculated path coefficients. In the young subjects, strong interactions were found from supplementary motor area (SMA) to sensorimotor cortex (SMC) via putamen and thalamus in SI task, whereas interactions were present only from premotor cortex (PM) to SMC in ET task. In the aged subjects, interactions decreased from SMA to putamen in SI task, and from PM to SMC in ET task. Additional interactions appeared between SMA and PM in both tasks. These results suggest the decline of primary loop function followed by compensatory recruitment of other mechanisms due to aging.

DESCENTE SPORTS SCIENCE Vol.25/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE