title: Across-muscle coherence is modulated as a function of wrist posture during two-digit grasping.
abstract: The purpose of this study was to investigate the extent to which correlated neural inputs, quantified as EMG-EMG coherence across intrinsic and extrinsic hand muscles, varied as a function of wrist angle during a constant force precision grip task. Eight adults (5 males; mean age 29 years) participated in the experiment. Subjects held an object using a two-digit precision grip at a constant force at a flexed, neutral, and extended wrist posture, while the EMG activity from intrinsic and extrinsic hand muscles was recorded through intramuscular fine-wire electrodes. The integral of z-transformed coherence computed across muscles pairs was greatest in the flexed wrist posture and significantly greater than EMG-EMG coherence measured in the neutral and extended wrist posture (P < 0.01 and 0.05, respectively). Furthermore, EMG-EMG coherence did not differ statistically between the extrinsic and intrinsic muscle pairs, even though it tended to be greater for the extrinsic muscle pair (P ≥ 0.063). These findings lend support to the notion of a functional role of correlated neural inputs to hand muscles for the task-dependent coordination of hand muscle activity that is likely mediated by somatosensory feedback.
authors: School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287-9709, United States.
authors: Mark
authors: M
authors: Jesunathadas
authors: Juan
authors: J
authors: Laitano
authors: Thomas M
authors: TM
authors: Hamm
authors: Marco
authors: M
authors: Santello
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D005385:Fingers; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture; D014953:Wrist / Q000502:physiology*; D055815:Young Adult
keywords: Coordination; Electromyography; Force; Hand
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