首页|Gradient descent decomposition of force-field motor primitives optogenetically elicited for motor mapping of the murine lumbosacral spinal cord

Gradient descent decomposition of force-field motor primitives optogenetically elicited for motor mapping of the murine lumbosacral spinal cord

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Generating diverse motor behaviors critical for survival is a challenge that confronts the central nervous system (CNS)of all animals. During movement execution, the CNS performs complex calculations to control a large number of neuromusculoskeletal elements. The theory of modular motor control proposes that spinal interneurons are organized in discrete modules that can be linearly combined to generate a variety of behavioral patterns.These modules have been previously represented as stimulus-evoked force fields (FFs) comprising isometric limb-endpoint forces across workspace locations. Here, we ask whether FFs elicited by different stimulations indeed represent the most elementary units of motor control or are themselves the combination of a limited number of even more fundamental motor modules. To probe for potentially more elementary modules, we optogenetically stimulated the lumbosacral spinal cord of intact and spinalized Thy1-ChR2 transgenic mice (n=21), eliciting FFs from as many single stimulation loci as possible (20-70 loci per mouse)at minimally necessary power. We found that the resulting varieties of FFs defied simple categorization with just a few clusters. We used gradient descent to further decompose the FFs into their underlying basic force fields (BFFs),whose linear combination explained FF variability. Across mice, we identified 4-5 BFFs with partially localizable but overlapping representations along the spinal cord. The BFFs were structured and topographically distributed in such a way that a rostral-to-caudal traveling wave of activity across the lumbosacral spinal cord may generate a swing-to-stance gait cycle. These BFFs may represent more rudimentary submodules that can be flexibly merged to produce a library of motor modules for building different motor behaviors.

Motor mappingOptogeneticsSpinal cordMotor primitivesTraveling wave

Paola Salmas、Vincent C.K Cheung

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School of Biomedical Sciences,and Gerald Choa Neuroscience Institute,The Chinese University of Hong Kong,Hong Kong SAR,China

Kunming Institute of Zoology-The Chinese University of Hong Kong(KIZ-CUHK)Joint Laboratory of Bioresources and Molecular Research of Common Diseases,Hong Kong SAR,China

CUHK Faculty of Medicine Faculty Innovation Award FIA2016/A/04 (to V.C.K.C.)Group Research SchemeHong Kong Research Grants CouncilHong Kong Research Grants CouncilHong Kong Research Grants CouncilHong Kong Research Grants CouncilHong Kong Research Grants Council

NL/JW/rc/grs1819/0426/19hc24115318CUHK-R4022-181411472114119022

2023

10.24272/j.issn.2095-8137.2022.276

动物学研究
中国科学院昆明动物研究所 中国动物学会

动物学研究

CSTPCDCSCD
影响因子：0.582
ISSN：0254-5853
年,卷(期)：2023.44(3)
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