Enhanced somatosensory feedback modulates cutaneous reflexes in arm muscles during self-triggered or prolonged stimulation.

Enhanced somatosensory feedback modulates cutaneous reflexes in arm muscles during self-triggered or prolonged stimulation. Exp Brain Res. 2020 Jan 02;: Authors: Sun Y, Pearcey GEP, Zehr EP Abstract Somatosensory feedback plays important roles in regulating all animal movement. The effects of sensory feedback on spinally mediated neural excitability are widely studied using cutaneous electrical stimulation paradigms. Cutaneous reflex amplitudes are reduced when stimulation is self-triggered instead of externally triggered. Altered spinal excitability and motor output are also observed following sustained stimulation with various parameters. Our purpose was to probe for interactions between mode and duration by investigating muscle responses following enhanced cutaneous stimulation. Fifteen neurologically intact participants were recruited. Cutaneous reflexes in the extensor carpi radialis (ECR) were evoked with brief (15 ms, 300 Hz) or sustained (300 ms, 50 Hz) stimulation trains. Stimulation was applied to the superficial radial or median nerve at the wrist and triggered by: (1) a computer program (random-triggered); (2) muscle contraction (EMG-triggered); (3) the participant pressing a button themselves (button-triggered). During each condition, isometric contractions were performed with ECR muscle activity maintained at 10, 25, 35, and 50% of maximal voluntary contraction. Stronger inhibitory reflexes were found following bri...
Source: Experimental Brain Research - Category: Neuroscience Authors: Tags: Exp Brain Res Source Type: research