Proximal and distal spinal neurons innervating multiple synergist and antagonist motor pools

eLife

Camille Lancelin¹  Robert M Brownstone¹  Remi Ronzano¹  Gardave Singh Bhumbra²  Marco Beato³ 

[1] Department of Neuromuscular Diseases, University College London, London, United Kingdom;Department of Neuroscience Physiology and Pharmacology, University College London, London, United Kingdom;Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom;

关键词: spinal cord;    trans-synaptic tracing;    rabies;    premotor interneurons;    motoneurons;    Mouse;   

DOI  :  10.7554/eLife.70858

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Motoneurons (MNs) control muscle contractions, and their recruitment by premotor circuits is tuned to produce accurate motor behaviours. To understand how these circuits coordinate movement across and between joints, it is necessary to understand whether spinal neurons pre-synaptic to motor pools have divergent projections to more than one MN population. Here, we used modified rabies virus tracing in mice to investigate premotor interneurons projecting to synergist flexor or extensor MNs, as well as those projecting to antagonist pairs of muscles controlling the ankle joint. We show that similar proportions of premotor neurons diverge to synergist and antagonist motor pools. Divergent premotor neurons were seen throughout the spinal cord, with decreasing numbers but increasing proportion with distance from the hindlimb enlargement. In the cervical cord, divergent long descending propriospinal neurons were found in contralateral lamina VIII, had large somata, were neither glycinergic, nor cholinergic, and projected to both lumbar and cervical MNs. We conclude that distributed spinal premotor neurons coordinate activity across multiple motor pools and that there are spinal neurons mediating co-contraction of antagonist muscles.

【 授权许可】

CC BY