Cracking the neural code of human movement.Pearcey, Gregory (PI). Memorial University.
Due to limits in technology, motor unit studies have formerly relied on limited samples of motor units, tasks with limited movement, and focused on muscles chosen for ease of motor unit identification rather than considering their functional roles. The overall goals of this project are: 1) to decode the majority of the motoneuron pool to reveal motor unit recruitment and rate coding strategies across diverse muscle groups, and 2) to examine task-dependent alterations in motor unit recruitment and spike patterns across dynamic motor tasks. Generating an atlas of recruitment and spike patterns across diverse muscle groups and motor tasks will dramatically enhance our understanding of human movement control, with implications for augmentation and repair of movement after injury and/or disease.
The neural control of dorsal neck muscles in non-human primates. Corneil, Brian (PI). Western University.
The muscles of the neck are fundamental for motor control; our eyes and ears are mounted on a mobile head, hence neck muscle recruitment must be coordinated with movement of other body segments for accurate orienting and behaviour in the real world. It has long been recognized that neck muscle anatomy is highly complex, featuring compartmentalizations and sharp heterogeneities in muscle fiber distribution, but we know virtually nothing about the physiological relevance of these complexities. The purpose of this grant is to define neck muscle recruitment synergies, leveraging the unique capabilities of Myomatrix arrays to simultaneously sample motor units within a given muscle and across multiple muscles.
Accelerator Grants
Quantitative Electrophysiological Analysis in Human Nerve Transfer Surgery.Rice, Charles (PI). St. Joseph’s Hospital.
Nerve transfer surgery is often performed following a peripheral nerve injury in which the odds of spontaneous recovery are unfavorable; however, despite its regular use, little is known about the properties of nascent motor units following nerve transfer surgery. The aim of this project is to use the Myomatrix arrays to quantify the properties of nascent motor units post nerve transfer surgery to better understand the process, timing and definition of reinnervated motor units. Results will provide a greater understanding of the basic properties and neurophysiological characteristics of motor units affected by nerve transfer surgery leading to improved clinical outcomes.
Exploring human motor unit recruitment changes between reciprocal and co-contraction patterns of muscle activity.Scott, Steve (PI). Queen’s University.
Most motor actions involve reciprocal patterns of activity between agonist and antagonist muscle groups, but co-contraction of antagonist muscles is commonly observed when performing difficult or novel motor tasks. While motor units generally follow an orderly recruitment pattern, our hypothesis is that co-contraction will lead to changes in this recruitment order. To test this hypothesis, we will compare motor unit recruitment patterns when resisting applied loads versus voluntarily altering co-contraction levels, in both static and dynamic contexts.
Investigating when, where, why, and how movement preparation occurs in the nervous system.Michaels, Jonathan (PI). York University.
It is generally accepted that movements must be prepared before they can be executed and that longer preparation times lead to faster and more accurate movements. However, it is unclear how much of this preparation relies on neural activity at the spinal cord level. This project investigates how movement preparation operates at the level of the spinal cord using a combination of surface muscle recordings, motor unit recordings, and biomechanical modelling during reaching movements.
Probing the flexibility of supraspinal control of motoneurons innervating forearm muscles.Perich, Matt (PI). University of Montreal.
This project explores the flexibility in the relationships between cortical neurons and the spinal motor units that innervate forearm muscles. We will compare how motor unit recruitment across behaviors of varying complexity to determine how descending inputs from the motor cortex to the spinal cord can rapidly reconfigure patterns of MU recruitment based on behavioral demands.