Aging differentially affects online control and offline control in finger force production

• Published in: PloS one Vol. 13; no. 5; p. e0198084
• Main Authors: Park, Yang Sun, Koh, Kyung, Kwon, Hyun Joon, Lee, Okjin, Shim, Jae Kun
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 31.05.2018; Public Library of Science (PLoS)
• Subjects: Activities of daily living; Aged; Aging; Aging (Biology); Aging - physiology; Analysis; Biology and Life Sciences; Brain research; Central nervous system; Central Nervous System - physiology; Covariance; Decomposition; Engineering schools; Equilibrium; Female; Finger; Fingers; Fingers - physiology; Geriatrics; Hand; Hand Strength - physiology; Human mechanics; Human subjects; Humans; Influence; Internet; Kinesiology; Male; Mechanical engineering; Medicine and Health Sciences; Neurosciences; Older people; Online Systems; People and Places; Physical Sciences; Physiological aspects; Physiology; Quality of life; Sport science; Sports medicine; Torque; Young Adult; United States > US; South Korea
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0198084

Human central nervous system (CNS) undergoes neurological changes during the aging process, leading to declines in hand and finger functions. Previous studies have shown that the CNS can independently process multi-finger force control and moment of force control. However, if both force and moment control are simultaneously imposed by motor task constraints, the CNS needs to resolve competing interests of generating negative and positive covariances between fingers, respectively, which causes "conflict of interest or COI". Here, we investigated how aging affects the CNS's abilities to solve COI through a new experimental paradigm. Both elderly and young subjects performed a constant force production task using index and middle fingers under two conditions, multi-finger pressing with no COI and with COI. We found that the elderly increased variance of a virtual finger (VF: an imagined finger producing the same mechanical effect as both fingers together) in time-to-time basis (i.e. online control), while increasing covariance between individual fingers (IF) forces in trial-to-trial basis (i.e. offline control) with COI than no COI. Aging affects the CNS's abilities to solve COI by deteriorating VF actions in online control and IF actions in offline control.