Proactive Selective Inhibition Targeted at the Neck Muscles: This Proximal Constraint Facilitates Learning and Regulates Global Control

Abstract

While individual muscle function is known, the sensory and motor value of muscles within the whole-body sensorimotor network is complicated. Specifically, the relationship between neck muscle action and distal muscle synergies is unknown. This work demonstrates a causal relationship between regulation of the neck muscles and global motor control. Studying violinists performing unskilled and skilled manual tasks, we provided ultrasound feedback of the neck muscles with instruction to minimize neck muscle change during task performance and observed the indirect effect on whole-body movement. Analysis of ultrasound, kinematic, electromyographic and electrodermal recordings showed that proactive inhibition targeted at neck muscles had an indirect global effect reducing the cost of movement, reducing complex involuntary, task-irrelevant movement patterns and improving balance. This effect was distinct from the effect of gaze alignment which increased physiological cost and reduced laboratory-referenced movement. Neck muscle inhibition imposes a proximal constraint on the global motor plan, forcing a change in highly automated sensorimotor control. The proximal location ensures global influence. The criterion, inhibition of unnecessary action, ensures reduced cost while facilitating task-relevant variation. This mechanism regulates global motor function and facilitates reinforcement learning to change engrained, maladapted sensorimotor control associated with chronic pain, injury and performance limitation.

Visuo‐manual tracking: does intermittent control with aperiodic sampling explain linear power and non‐linear remnant without sensorimotor noise?

“…; Loram et al . , ; Loram, ) at a temporal scale of 200–500 ms, rather than the more traditional location which is outside the inner control loop (Skogestad & Postlethwaite, ; Pruszynski & Scott, ) at the level of action selection. Extending these executive processes within the feedback loop to the level of sub‐movements gives biological control its characteristic flexibility and adaptability still not observed in engineering systems (Loram et al .…”

Estimation of absolute states of human skeletal muscle via standard B-mode ultrasound imaging and deep convolutional neural networks

“…In science, we need activity, particularly from deep muscles in the neck, back, lower and upper limbs, to understand how control of the muscular system is organised. Muscular control is hierarchical and synergistic in nature, and currently that science is immature simply because we cannot measure activity easily in all the important deep muscles [6]. In medicine, healthy control of muscles has broken down for many possible reasons.…”

“…Work-related upper limb and neck musculoskeletal disorders are one of the most common occupational disorders around the world [5] and the cost of these in the EU has been estimated to be between 0.5% and 2% of gross national product [5]. Personalised diagnosis requires available, non-invasive, accurate, objective measurement of function and condition for skeletal muscles throughout the body [2]- [4], [6], [7].…”

Automated analysis of neck muscle boundaries for cervical dystonia using ultrasound imaging and deep learning

“…Linked US-Vicon dataset: Forty seven retroreflective markers were attached to the body to allow motion analysis of eighteen body segments (head, neck, thorax, pelvis, thighs, shanks, feet, clavicles, upper arms, forearms, hand) [14]. Participants stood in the middle of the calibrated volume and were instructed to perform pitch (flexion/extension), yaw (right/left) and roll (right side/left side) head rotations, turning their heads as far as possible in both directions and each trial was repeated starting in the opposite direction.…”