Inter-dependence between mathematically independent variability components in human multi-finger force control

Publication date: Available online 14 September 2019Source: Neuroscience ResearchAuthor(s): Yushin Kim, Kyung Koh, Jae Kun ShimAbstractIn human movement control, inherent error or uncertainty in the controller, motor system, and sensory system causes variability in motor outcomes. Previous studies have suggested different methods to quantify and examine independent components of the motor variability of motor outputs in a redundant motor system. While these motor variability components are mathematically independent, it is unknown if these components are behaviorally independent among subjects. The aim of this study was to investigate inter-relations between mathematically independent motor variability components in multi-finger force control among subjects. Nineteen healthy subjects performed two tasks, producing a constant force and a sinusoidal force for 12 seconds over 12 trials. We used the hierarchical variability decomposition (HVD) model to quantify mathematically independent variability components, i.e., online task-relevant variance (onTRV), online task-irrelevant variance (onTIV), offline task-relevant variance (offTRV), and offline task-irrelevant variance (offTIV) for each subject. The correlation analysis performed among all subjects showed that online and offline motor variability components were positively correlated, while task-relevant and –irrelevant variability components were not. The results indicate that these mathematically independent motor variabil...
Source: Neuroscience Research - Category: Neuroscience Source Type: research