1
|
Li L, Chen H, Deng L, Huang Y, Zhang Y, Luo Y, Ou P, Shi L, Dai L, Chen W, Chen H, Wang J, Liu C. Imbalanced optimal feedback motor control system in spinocerebellar ataxia type 3. Eur J Neurol 2024; 31:e16368. [PMID: 38923784 PMCID: PMC11295168 DOI: 10.1111/ene.16368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/02/2024] [Accepted: 05/12/2024] [Indexed: 06/28/2024]
Abstract
BACKGROUND AND PURPOSE Human motor planning and control depend highly on optimal feedback control systems, such as the neocortex-cerebellum circuit. Here, diffusion tensor imaging was used to verify the disruption of the neocortex-cerebellum circuit in spinocerebellar ataxia type 3 (SCA3), and the circuit's disruption correlation with SCA3 motor dysfunction was investigated. METHODS This study included 45 patients with familial SCA3, aged 17-67 years, and 49 age- and sex-matched healthy controls, aged 21-64 years. Tract-based spatial statistics and probabilistic tractography was conducted using magnetic resonance images of the patients and controls. The correlation between the local probability of probabilistic tractography traced from the cerebellum and clinical symptoms measured using specified symptom scales was also calculated. RESULTS The cerebellum-originated probabilistic tractography analysis showed that structural connectivity, mainly in the subcortical cerebellar-thalamo-cortical tract, was significantly reduced and the cortico-ponto-cerebellar tract was significantly stronger in the SCA3 group than in the control group. The enhanced tract was extended to the right lateral parietal region and the right primary motor cortex. The enhanced neocortex-cerebellum connections were highly associated with disease progression, including duration and symptomatic deterioration. Tractography probabilities from the cerebellar to parietal and sensorimotor areas were significantly negatively correlated with motor abilities in patients with SCA3. CONCLUSION To our knowledge, this study is the first to reveal that disrupting the neocortex-cerebellum loop can cause SCA3-induced motor dysfunctions. The specific interaction between the cerebellar-thalamo-cortical and cortico-ponto-cerebellar pathways in patients with SCA3 and its relationship with ataxia symptoms provides a new direction for future research.
Collapse
Affiliation(s)
- Leinian Li
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
- School of PsychologyShandong Normal UniversityJinanChina
| | - Hui Chen
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - LiHua Deng
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - YongHua Huang
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - YuHan Zhang
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - YueYuan Luo
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - PeiLing Ou
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - LinFeng Shi
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - LiMeng Dai
- Department of Medical Genetics, College of Basic Medical ScienceArmy Medical University (Third Military Medical University)ChongqingChina
| | - Wei Chen
- MR Research Collaboration TeamSiemens Healthineers Ltd.WuhanChina
| | - HuaFu Chen
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
- MOE Key Laboratory for Neuro Information, High‐Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan ProvinceUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Jian Wang
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| | - Chen Liu
- 7T Magnetic Resonance Translational Medicine Research Center, Department of Radiology, Southwest HospitalArmy Medical University (Third Military Medical University)ChongqingChina
| |
Collapse
|
2
|
Furuta T, Morita T, Miura G, Naito E. Structural and functional features characterizing the brains of individuals with higher controllability of motor imagery. Sci Rep 2024; 14:17243. [PMID: 39060339 PMCID: PMC11282224 DOI: 10.1038/s41598-024-68425-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 07/23/2024] [Indexed: 07/28/2024] Open
Abstract
Motor imagery is a higher-order cognitive brain function that mentally simulates movements without performing the actual physical one. Although motor imagery has attracted the interest of many researchers, and mental practice utilizing motor imagery has been widely used in sports training and post-stroke rehabilitation, neural bases that determine individual differences in motor imagery ability are not well understood. In this study, using controllability of motor imagery (CMI) test that can objectively evaluate individual ability to manipulate one's imaginary postures, we examined structural and functional features characterizing the brains of individuals with higher controllability of motor imagery, by analyzing T1-weighted structural MRI data obtained from 89 participants and functional MRI data obtained from 28 of 89 participants. The higher CMI test scorers had larger volume in the bilateral superior frontoparietal white matter regions. The CMI test activated the bilateral dorsal premotor cortex (PMD) and superior parietal lobule (SPL); specifically, the left PMD and/or the right SPL enhanced functional coupling with the visual body, somatosensory, and motor/kinesthetic areas in the higher scorers. Hence, controllability of motor imagery is higher for those who well-develop superior frontoparietal network, and for those whose this network accesses these sensory areas to predict the expected multisensory experiences during motor imagery. This study elucidated for the first time the structural and functional features characterizing the brains of individuals with higher controllability of motor imagery, and advanced understanding of individual differences in motor imagery ability.
Collapse
Affiliation(s)
- Tomoya Furuta
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomoyo Morita
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Gen Miura
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Eiichi Naito
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| |
Collapse
|
3
|
Sadeghi M, Sharif Razavian R, Bazzi S, Chowdhury RH, Batista AP, Loughlin PJ, Sternad D. Inferring control objectives in a virtual balancing task in humans and monkeys. eLife 2024; 12:RP88514. [PMID: 38738986 PMCID: PMC11090506 DOI: 10.7554/elife.88514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Natural behaviors have redundancy, which implies that humans and animals can achieve their goals with different strategies. Given only observations of behavior, is it possible to infer the control objective that the subject is employing? This challenge is particularly acute in animal behavior because we cannot ask or instruct the subject to use a particular strategy. This study presents a three-pronged approach to infer an animal's control objective from behavior. First, both humans and monkeys performed a virtual balancing task for which different control strategies could be utilized. Under matched experimental conditions, corresponding behaviors were observed in humans and monkeys. Second, a generative model was developed that represented two main control objectives to achieve the task goal. Model simulations were used to identify aspects of behavior that could distinguish which control objective was being used. Third, these behavioral signatures allowed us to infer the control objective used by human subjects who had been instructed to use one control objective or the other. Based on this validation, we could then infer objectives from animal subjects. Being able to positively identify a subject's control objective from observed behavior can provide a powerful tool to neurophysiologists as they seek the neural mechanisms of sensorimotor coordination.
Collapse
Affiliation(s)
- Mohsen Sadeghi
- Department of Biology, Northeastern UniversityBostonUnited States
| | - Reza Sharif Razavian
- Department of Biology, Northeastern UniversityBostonUnited States
- Department of Electrical and Computer Engineering, Northeastern UniversityBostonUnited States
- Department of Mechanical Engineering, Northern Arizona UniversityFlagstaffUnited States
| | - Salah Bazzi
- Department of Biology, Northeastern UniversityBostonUnited States
- Department of Electrical and Computer Engineering, Northeastern UniversityBostonUnited States
- Institute for Experiential Robotics, Northeastern UniversityBostonUnited States
| | - Raeed H Chowdhury
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of PittsburghPittsburghUnited States
| | - Aaron P Batista
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of PittsburghPittsburghUnited States
| | - Patrick J Loughlin
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of PittsburghPittsburghUnited States
| | - Dagmar Sternad
- Department of Biology, Northeastern UniversityBostonUnited States
- Department of Electrical and Computer Engineering, Northeastern UniversityBostonUnited States
- Institute for Experiential Robotics, Northeastern UniversityBostonUnited States
- Department of Physics, Northeastern UniversityBostonUnited States
| |
Collapse
|
4
|
Gotoh M, Dezawa S, Takashima I, Yamamoto S. Effects of focal cortical cooling on somatosensory evoked potentials in rats. Brain Res 2024; 1840:148995. [PMID: 38735427 DOI: 10.1016/j.brainres.2024.148995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 05/14/2024]
Abstract
Although the focal brain cooling technique is widely used to examine brain function, the effects of cortical temperature at various levels on sensory information processing and neural mechanisms remain underexplored. To elucidate the mechanisms of temperature modulation in somatosensory processing, this study aimed to examine how P1 and N1 deflections of somatosensory evoked potentials (SEPs) depend on cortical temperature and how excitatory and inhibitory inputs contribute to this temperature dependency. SEPs were generated through electrical stimulation of the contralateral forepaw in anesthetized rats. The SEPs were recorded while cortical temperatures were altered between 17-38 °C either without any antagonists, with a gamma-aminobutyric acid type A (GABAA) receptor antagonist (gabazine), with an aminomethylphosphonic acid (AMPA) receptor antagonist (NBQX), or with an N-Methyl-D-aspartic acid (NMDA) receptor antagonist ([R]-CPP). The effects of different gabazine concentrations (0, 1, and 10 µM) were examined in the 35-38 °C range. The P1/N1 amplitudes and their peak-to-peak differences plotted against cortical temperature showed an inverted U relationship with a maximum at approximately 27.5 °C when no antagonists were administered. The negative correlation between these amplitudes and temperatures of ≥ 27.5 °C plateaued after gabazine administration, which occurred progressively as the gabazine concentration increased. In contrast, the correlation remained negative after the administration of NBQX and (R)-CPP. These results suggest that GABAergic inhibitory inputs contribute to the negative correlation between SEP amplitude and cortical temperature around the physiological cortical temperature.
Collapse
Affiliation(s)
- Mizuho Gotoh
- Department of Information Technology and Human Factors, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Japan; Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Shinnosuke Dezawa
- Department of Information Technology and Human Factors, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Japan; Faculty of Medical and Health Sciences, Tsukuba International University, Tsuchiura, Japan
| | - Ichiro Takashima
- Department of Information Technology and Human Factors, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Japan; Department of Information, Artificial Intelligence and Data Science, Daiichi Institute of Technology, Tokyo, Japan
| | - Shinya Yamamoto
- Department of Information Technology and Human Factors, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Japan.
| |
Collapse
|
5
|
Greene P, Bastian AJ, Schieber MH, Sarma SV. Optimal reaching subject to computational and physical constraints reveals structure of the sensorimotor control system. Proc Natl Acad Sci U S A 2024; 121:e2319313121. [PMID: 38551834 PMCID: PMC10998569 DOI: 10.1073/pnas.2319313121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/13/2024] [Indexed: 04/02/2024] Open
Abstract
Optimal feedback control provides an abstract framework describing the architecture of the sensorimotor system without prescribing implementation details such as what coordinate system to use, how feedback is incorporated, or how to accommodate changing task complexity. We investigate how such details are determined by computational and physical constraints by creating a model of the upper limb sensorimotor system in which all connection weights between neurons, feedback, and muscles are unknown. By optimizing these parameters with respect to an objective function, we find that the model exhibits a preference for an intrinsic (joint angle) coordinate representation of inputs and feedback and learns to calculate a weighted feedforward and feedback error. We further show that complex reaches around obstacles can be achieved by augmenting our model with a path-planner based on via points. The path-planner revealed "avoidance" neurons that encode directions to reach around obstacles and "placement" neurons that make fine-tuned adjustments to via point placement. Our results demonstrate the surprising capability of computationally constrained systems and highlight interesting characteristics of the sensorimotor system.
Collapse
Affiliation(s)
- Patrick Greene
- Institute for Computational Medicine, The Johns Hopkins University, Baltimore, MD21218
| | - Amy J. Bastian
- Kennedy Krieger Institute, Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Marc H. Schieber
- Department of Neurology, University of Rochester, Rochester, NY14642
| | - Sridevi V. Sarma
- Institute for Computational Medicine, The Johns Hopkins University, Baltimore, MD21218
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine & Whiting School of Engineering, Baltimore, MD21218
| |
Collapse
|
6
|
Almani MN, Lazzari J, Chacon A, Saxena S. μSim: A goal-driven framework for elucidating the neural control of movement through musculoskeletal modeling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578628. [PMID: 38405828 PMCID: PMC10888726 DOI: 10.1101/2024.02.02.578628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
How does the motor cortex (MC) produce purposeful and generalizable movements from the complex musculoskeletal system in a dynamic environment? To elucidate the underlying neural dynamics, we use a goal-driven approach to model MC by considering its goal as a controller driving the musculoskeletal system through desired states to achieve movement. Specifically, we formulate the MC as a recurrent neural network (RNN) controller producing muscle commands while receiving sensory feedback from biologically accurate musculoskeletal models. Given this real-time simulated feedback implemented in advanced physics simulation engines, we use deep reinforcement learning to train the RNN to achieve desired movements under specified neural and musculoskeletal constraints. Activity of the trained model can accurately decode experimentally recorded neural population dynamics and single-unit MC activity, while generalizing well to testing conditions significantly different from training. Simultaneous goal- and data- driven modeling in which we use the recorded neural activity as observed states of the MC further enhances direct and generalizable single-unit decoding. Finally, we show that this framework elucidates computational principles of how neural dynamics enable flexible control of movement and make this framework easy-to-use for future experiments.
Collapse
|
7
|
Ito S, Gomi H. Modulations of stretch reflex by altering visuomotor contexts. Front Hum Neurosci 2024; 18:1336629. [PMID: 38419960 PMCID: PMC10899434 DOI: 10.3389/fnhum.2024.1336629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 02/02/2024] [Indexed: 03/02/2024] Open
Abstract
Various functional modulations of the stretch reflex help to stabilize actions, but the computational mechanism behind its context-dependent tuning remains unclear. While many studies have demonstrated that motor contexts associated with the task goal cause functional modulation of the stretch reflex of upper limbs, it is not well understood how visual contexts independent of the task requirements affect the stretch reflex. To explore this issue, we conducted two experiments testing 20 healthy human participants (age range 20-45, average 31.3 ± 9.0), in which visual contexts were manipulated in a visually guided reaching task. During wrist flexion movements toward a visual target, a mechanical load was applied to the wrist joint to evoke stretch reflex of wrist flexor muscle (flexor carpi radialis). The first experiment (n = 10) examined the effect of altering the visuomotor transformation on the stretch reflex that was evaluated with surface electromyogram. We found that the amplitude of the stretch reflex decreased (p = 0.024) when a rotational transformation of 90° was introduced between the hand movement and the visual cursor, whereas the amplitude did not significantly change (p = 0.26) when the rotational transformation was accompanied by a head rotation so that the configuration of visual feedback was maintained in visual coordinates. The results suggest that the stretch reflex was regulated depending on whether the visuomotor mapping had already been acquired or not. In the second experiment (n = 10), we examined how uncertainty in the visual target or hand cursor affects the stretch reflex by removing these visual stimuli. We found that the reflex amplitude was reduced by the disappearance of the hand cursor (p = 0.039), but was not affected by removal of the visual target (p = 0.27), suggesting that the visual state of the body and target contribute differently to the reflex tuning. These findings support the idea that visual updating of the body state is crucial for regulation of quick motor control driven by proprioceptive signals.
Collapse
Affiliation(s)
- Sho Ito
- NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Atsugi, Japan
- School of Engineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroaki Gomi
- NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Atsugi, Japan
| |
Collapse
|
8
|
Cross KP, Cook DJ, Scott SH. Rapid Online Corrections for Proprioceptive and Visual Perturbations Recruit Similar Circuits in Primary Motor Cortex. eNeuro 2024; 11:ENEURO.0083-23.2024. [PMID: 38238081 PMCID: PMC10867723 DOI: 10.1523/eneuro.0083-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 12/22/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024] Open
Abstract
An important aspect of motor function is our ability to rapidly generate goal-directed corrections for disturbances to the limb or behavioral goal. The primary motor cortex (M1) is a key region involved in processing feedback for rapid motor corrections, yet we know little about how M1 circuits are recruited by different sources of sensory feedback to make rapid corrections. We trained two male monkeys (Macaca mulatta) to make goal-directed reaches and on random trials introduced different sensory errors by either jumping the visual location of the goal (goal jump), jumping the visual location of the hand (cursor jump), or applying a mechanical load to displace the hand (proprioceptive feedback). Sensory perturbations evoked a broad response in M1 with ∼73% of neurons (n = 257) responding to at least one of the sensory perturbations. Feedback responses were also similar as response ranges between the goal and cursor jumps were highly correlated (range of r = [0.91, 0.97]) as were the response ranges between the mechanical loads and the visual perturbations (range of r = [0.68, 0.86]). Lastly, we identified the neural subspace each perturbation response resided in and found a strong overlap between the two visual perturbations (range of overlap index, 0.73-0.89) and between the mechanical loads and visual perturbations (range of overlap index, 0.36-0.47) indicating each perturbation evoked similar structure of activity at the population level. Collectively, our results indicate rapid responses to errors from different sensory sources target similar overlapping circuits in M1.
Collapse
Affiliation(s)
- Kevin P Cross
- Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Douglas J Cook
- Department of Surgery, Queen's University, Kingston, Ontario K7L 3N6, Canada
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Stephen H Scott
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
- Departments of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
- Medicine, Queen's University, Kingston, Ontario K7L 3N6, Canada
| |
Collapse
|
9
|
Sadeghi M, Razavian RS, Bazzi S, Chowdhury R, Batista A, Loughlin P, Sternad D. Inferring control objectives in a virtual balancing task in humans and monkeys. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539055. [PMID: 37205497 PMCID: PMC10187212 DOI: 10.1101/2023.05.02.539055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Natural behaviors have redundancy, which implies that humans and animals can achieve their goals with different control objectives. Given only observations of behavior, is it possible to infer the control strategy that the subject is employing? This challenge is particularly acute in animal behavior because we cannot ask or instruct the subject to use a particular control strategy. This study presents a threepronged approach to infer an animal's control strategy from behavior. First, both humans and monkeys performed a virtual balancing task for which different control objectives could be utilized. Under matched experimental conditions, corresponding behaviors were observed in humans and monkeys. Second, a generative model was developed that represented two main control strategies to achieve the task goal. Model simulations were used to identify aspects of behavior that could distinguish which control objective was being used. Third, these behavioral signatures allowed us to infer the control objective used by human subjects who had been instructed to use one control objective or the other. Based on this validation, we could then infer strategies from animal subjects. Being able to positively identify a subject's control objective from behavior can provide a powerful tool to neurophysiologists as they seek the neural mechanisms of sensorimotor coordination.
Collapse
Affiliation(s)
- Mohsen Sadeghi
- Department of Biology, Northeastern University
- Department of Electrical and Computer Engineering, Northeastern University
| | | | - Salah Bazzi
- Institute for Experiential Robotics, Northeastern University
| | - Raeed Chowdhury
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of Pittsburgh, PA, USA
| | - Aaron Batista
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of Pittsburgh, PA, USA
| | - Patrick Loughlin
- Department of Bioengineering, and Center for the Neural Basis of Cognition, University of Pittsburgh, PA, USA
| | - Dagmar Sternad
- Department of Biology, Northeastern University
- Department of Electrical and Computer Engineering, Northeastern University
- Institute for Experiential Robotics, Northeastern University
- Department of Physics, Northeastern University
| |
Collapse
|
10
|
Maurus P, Jackson K, Cashaback JG, Cluff T. The nervous system tunes sensorimotor gains when reaching in variable mechanical environments. iScience 2023; 26:106756. [PMID: 37213228 PMCID: PMC10197011 DOI: 10.1016/j.isci.2023.106756] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/10/2023] [Accepted: 04/23/2023] [Indexed: 05/23/2023] Open
Abstract
Humans often move in the presence of mechanical disturbances that can vary in direction and amplitude throughout movement. These disturbances can jeopardize the outcomes of our actions, such as when drinking from a glass of water on a turbulent flight or carrying a cup of coffee while walking on a busy sidewalk. Here, we examine control strategies that allow the nervous system to maintain performance when reaching in the presence of mechanical disturbances that vary randomly throughout movement. Healthy participants altered their control strategies to make movements more robust against disturbances. The change in control was associated with faster reaching movements and increased responses to proprioceptive and visual feedback that were tuned to the variability of the disturbances. Our findings highlight that the nervous system exploits a continuum of control strategies to increase its responsiveness to sensory feedback when reaching in the presence of increasingly variable physical disturbances.
Collapse
Affiliation(s)
- Philipp Maurus
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Kuira Jackson
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Joshua G.A. Cashaback
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA
- Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, USA
- Biomechanics and Movement Science Program, University of Delaware, Newark, DE 19716, USA
| | - Tyler Cluff
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Corresponding author
| |
Collapse
|
11
|
Marciniak Dg Agra K, Dg Agra P. F = ma. Is the macaque brain Newtonian? Cogn Neuropsychol 2023; 39:376-408. [PMID: 37045793 DOI: 10.1080/02643294.2023.2191843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Intuitive Physics, the ability to anticipate how the physical events involving mass objects unfold in time and space, is a central component of intelligent systems. Intuitive physics is a promising tool for gaining insight into mechanisms that generalize across species because both humans and non-human primates are subject to the same physical constraints when engaging with the environment. Physical reasoning abilities are widely present within the animal kingdom, but monkeys, with acute 3D vision and a high level of dexterity, appreciate and manipulate the physical world in much the same way humans do.
Collapse
Affiliation(s)
- Karolina Marciniak Dg Agra
- The Rockefeller University, Laboratory of Neural Circuits, New York, NY, USA
- Center for Brain, Minds and Machines, Cambridge, MA, USA
| | - Pedro Dg Agra
- The Rockefeller University, Laboratory of Neural Circuits, New York, NY, USA
- Center for Brain, Minds and Machines, Cambridge, MA, USA
| |
Collapse
|
12
|
Floegel M, Kasper J, Perrier P, Kell CA. How the conception of control influences our understanding of actions. Nat Rev Neurosci 2023; 24:313-329. [PMID: 36997716 DOI: 10.1038/s41583-023-00691-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2023] [Indexed: 04/01/2023]
Abstract
Wilful movement requires neural control. Commonly, neural computations are thought to generate motor commands that bring the musculoskeletal system - that is, the plant - from its current physical state into a desired physical state. The current state can be estimated from past motor commands and from sensory information. Modelling movement on the basis of this concept of plant control strives to explain behaviour by identifying the computational principles for control signals that can reproduce the observed features of movements. From an alternative perspective, movements emerge in a dynamically coupled agent-environment system from the pursuit of subjective perceptual goals. Modelling movement on the basis of this concept of perceptual control aims to identify the controlled percepts and their coupling rules that can give rise to the observed characteristics of behaviour. In this Perspective, we discuss a broad spectrum of approaches to modelling human motor control and their notions of control signals, internal models, handling of sensory feedback delays and learning. We focus on the influence that the plant control and the perceptual control perspective may have on decisions when modelling empirical data, which may in turn shape our understanding of actions.
Collapse
Affiliation(s)
- Mareike Floegel
- Department of Neurology and Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Johannes Kasper
- Department of Neurology and Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Pascal Perrier
- Univ. Grenoble Alpes, CNRS, Grenoble INP, GIPSA-lab, Grenoble, France
| | - Christian A Kell
- Department of Neurology and Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany.
| |
Collapse
|
13
|
Proprioceptive and Visual Feedback Responses in Macaques Exploit Goal Redundancy. J Neurosci 2023; 43:787-802. [PMID: 36535766 PMCID: PMC9899082 DOI: 10.1523/jneurosci.1332-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/07/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
A common problem in motor control concerns how to generate patterns of muscle activity when there are redundant solutions to attain a behavioral goal. Optimal feedback control is a theory that has guided many behavioral studies exploring how the motor system incorporates task redundancy. This theory predicts that kinematic errors that deviate the limb should not be corrected if one can still attain the behavioral goal. Studies in humans demonstrate that the motor system can flexibly integrate visual and proprioceptive feedback of the limb with goal redundancy within 90 ms and 70 ms, respectively. Here, we show monkeys (Macaca mulatta) demonstrate similar abilities to exploit goal redundancy. We trained four male monkeys to reach for a goal that was either a narrow square or a wide, spatially redundant rectangle. Monkeys exhibited greater trial-by-trial variability when reaching to the wide goal consistent with exploiting goal redundancy. On random trials we jumped the visual feedback of the hand and found monkeys corrected for the jump when reaching to the narrow goal and largely ignored the jump when reaching for the wide goal. In a separate set of experiments, we applied mechanical loads to the arm of the monkey and found similar corrective responses based on goal shape. Muscle activity reflecting these different corrective responses were detected for the visual and mechanical perturbations starting at ∼90 and ∼70 ms, respectively. Thus, rapid motor responses in macaques can exploit goal redundancy similar to humans, creating a paradigm to study the neural basis of goal-directed motor action and motor redundancy.SIGNIFICANCE STATEMENT Moving in the world requires selecting from an infinite set of possible motor commands. Theories predict that motor commands are selected that exploit redundancies. Corrective responses in humans to either visual or proprioceptive disturbances of the limb can rapidly exploit redundant trajectories to a goal in <100 ms after a disturbance. However, uncovering the neural correlates generating these rapid motor corrections has been hampered by the absence of an animal model. We developed a behavioral paradigm in monkeys that incorporates redundancy in the form of the shape of the goal. Critically, monkeys exhibit corrective responses and timings similar to humans performing the same task. Our paradigm provides a model for investigating the neural correlates of sophisticated rapid motor corrections.
Collapse
|
14
|
Codol O, Kashefi M, Forgaard CJ, Galea JM, Pruszynski JA, Gribble PL. Sensorimotor feedback loops are selectively sensitive to reward. eLife 2023; 12:81325. [PMID: 36637162 PMCID: PMC9910828 DOI: 10.7554/elife.81325] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 12/29/2022] [Indexed: 01/14/2023] Open
Abstract
Although it is well established that motivational factors such as earning more money for performing well improve motor performance, how the motor system implements this improvement remains unclear. For instance, feedback-based control, which uses sensory feedback from the body to correct for errors in movement, improves with greater reward. But feedback control encompasses many feedback loops with diverse characteristics such as the brain regions involved and their response time. Which specific loops drive these performance improvements with reward is unknown, even though their diversity makes it unlikely that they are contributing uniformly. We systematically tested the effect of reward on the latency (how long for a corrective response to arise?) and gain (how large is the corrective response?) of seven distinct sensorimotor feedback loops in humans. Only the fastest feedback loops were insensitive to reward, and the earliest reward-driven changes were consistently an increase in feedback gains, not a reduction in latency. Rather, a reduction of response latencies only tended to occur in slower feedback loops. These observations were similar across sensory modalities (vision and proprioception). Our results may have implications regarding feedback control performance in athletic coaching. For instance, coaching methodologies that rely on reinforcement or 'reward shaping' may need to specifically target aspects of movement that rely on reward-sensitive feedback responses.
Collapse
Affiliation(s)
- Olivier Codol
- Brain and Mind Institute, University of Western OntarioLondonCanada
- Department of Psychology, University of Western OntarioLondonCanada
- School of Psychology, University of BirminghamBirminghamUnited Kingdom
| | - Mehrdad Kashefi
- Brain and Mind Institute, University of Western OntarioLondonCanada
- Department of Psychology, University of Western OntarioLondonCanada
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, University of Western OntarioOntarioCanada
- Robarts Research Institute, University of Western OntarioLondonCanada
| | - Christopher J Forgaard
- Brain and Mind Institute, University of Western OntarioLondonCanada
- Department of Psychology, University of Western OntarioLondonCanada
| | - Joseph M Galea
- School of Psychology, University of BirminghamBirminghamUnited Kingdom
| | - J Andrew Pruszynski
- Brain and Mind Institute, University of Western OntarioLondonCanada
- Department of Psychology, University of Western OntarioLondonCanada
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, University of Western OntarioOntarioCanada
- Robarts Research Institute, University of Western OntarioLondonCanada
| | - Paul L Gribble
- Brain and Mind Institute, University of Western OntarioLondonCanada
- Department of Psychology, University of Western OntarioLondonCanada
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, University of Western OntarioOntarioCanada
- Haskins LaboratoriesNew HavenUnited States
| |
Collapse
|
15
|
Izawa J, Higo N, Murata Y. Accounting for the valley of recovery during post-stroke rehabilitation training via a model-based analysis of macaque manual dexterity. FRONTIERS IN REHABILITATION SCIENCES 2022; 3:1042912. [PMID: 36644290 PMCID: PMC9838193 DOI: 10.3389/fresc.2022.1042912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
Background True recovery, in which a stroke patient regains the same precise motor skills observed in prestroke conditions, is the fundamental goal of rehabilitation training. However, a transient drop in task performance during rehabilitation training after stroke, observed in human clinical outcome as well as in both macaque and squirrel monkey retrieval data, might prevent smooth transitions during recovery. This drop, i.e., recovery valley, often occurs during the transition from compensatory skill to precision skill. Here, we sought computational mechanisms behind such transitions and recovery. Analogous to motor skill learning, we considered that the motor recovery process is composed of spontaneous recovery and training-induced recovery. Specifically, we hypothesized that the interaction of these multiple skill update processes might determine profiles of the recovery valley. Methods A computational model of motor recovery was developed based on a state-space model of motor learning that incorporates a retention factor and interaction terms for training-induced recovery and spontaneous recovery. The model was fit to previously reported macaque motor recovery data where the monkey practiced precision grip skills after a lesion in the sensorimotor area in the cortex. Multiple computational models and the effects of each parameter were examined by model comparisons based on information criteria and sensitivity analyses of each parameter. Result Both training-induced and spontaneous recoveries were necessary to explain the behavioral data. Since these two factors contributed following logarithmic function, the training-induced recovery were effective only after spontaneous biological recovery had developed. In the training-induced recovery component, the practice of the compensation also contributed to recovery of the precision grip skill as if there is a significant generalization effect of learning between these two skills. In addition, a retention factor was critical to explain the recovery profiles. Conclusions We found that spontaneous recovery, training-induced recovery, retention factors, and interaction terms are crucial to explain recovery and recovery valley profiles. This simulation-based examination of the model parameters provides suggestions for effective rehabilitation methods to prevent the recovery valley, such as plasticity-promoting medications, brain stimulation, and robotic rehabilitation technologies.
Collapse
Affiliation(s)
- Jun Izawa
- Faculty of Engineering, Information and Systems, University of Tsukuba, Tsukuba, Japan,Correspondence: Jun Izawa Yumi Murata
| | - Noriyuki Higo
- Neurorehabilitation Research Group, Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Yumi Murata
- Neurorehabilitation Research Group, Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan,Correspondence: Jun Izawa Yumi Murata
| |
Collapse
|
16
|
Thura D, Cabana JF, Feghaly A, Cisek P. Integrated neural dynamics of sensorimotor decisions and actions. PLoS Biol 2022; 20:e3001861. [PMID: 36520685 PMCID: PMC9754259 DOI: 10.1371/journal.pbio.3001861] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 09/29/2022] [Indexed: 12/23/2022] Open
Abstract
Recent theoretical models suggest that deciding about actions and executing them are not implemented by completely distinct neural mechanisms but are instead two modes of an integrated dynamical system. Here, we investigate this proposal by examining how neural activity unfolds during a dynamic decision-making task within the high-dimensional space defined by the activity of cells in monkey dorsal premotor (PMd), primary motor (M1), and dorsolateral prefrontal cortex (dlPFC) as well as the external and internal segments of the globus pallidus (GPe, GPi). Dimensionality reduction shows that the four strongest components of neural activity are functionally interpretable, reflecting a state transition between deliberation and commitment, the transformation of sensory evidence into a choice, and the baseline and slope of the rising urgency to decide. Analysis of the contribution of each population to these components shows meaningful differences between regions but no distinct clusters within each region, consistent with an integrated dynamical system. During deliberation, cortical activity unfolds on a two-dimensional "decision manifold" defined by sensory evidence and urgency and falls off this manifold at the moment of commitment into a choice-dependent trajectory leading to movement initiation. The structure of the manifold varies between regions: In PMd, it is curved; in M1, it is nearly perfectly flat; and in dlPFC, it is almost entirely confined to the sensory evidence dimension. In contrast, pallidal activity during deliberation is primarily defined by urgency. We suggest that these findings reveal the distinct functional contributions of different brain regions to an integrated dynamical system governing action selection and execution.
Collapse
Affiliation(s)
- David Thura
- Groupe de recherche sur la signalisation neurale et la circuiterie, Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
| | - Jean-François Cabana
- Groupe de recherche sur la signalisation neurale et la circuiterie, Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
| | - Albert Feghaly
- Groupe de recherche sur la signalisation neurale et la circuiterie, Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
| | - Paul Cisek
- Groupe de recherche sur la signalisation neurale et la circuiterie, Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
| |
Collapse
|
17
|
Silva AB, Liu JR, Zhao L, Levy DF, Scott TL, Chang EF. A Neurosurgical Functional Dissection of the Middle Precentral Gyrus during Speech Production. J Neurosci 2022; 42:8416-8426. [PMID: 36351829 PMCID: PMC9665919 DOI: 10.1523/jneurosci.1614-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Classical models have traditionally focused on the left posterior inferior frontal gyrus (Broca's area) as a key region for motor planning of speech production. However, converging evidence suggests that it is not critical for either speech motor planning or execution. Alternative cortical areas supporting high-level speech motor planning have yet to be defined. In this review, we focus on the precentral gyrus, whose role in speech production is often thought to be limited to lower-level articulatory muscle control. In particular, we highlight neurosurgical investigations that have shed light on a cortical region anatomically located near the midpoint of the precentral gyrus, hence called the middle precentral gyrus (midPrCG). The midPrCG is functionally located between dorsal hand and ventral orofacial cortical representations and exhibits unique sensorimotor and multisensory functions relevant for speech processing. This includes motor control of the larynx, auditory processing, as well as a role in reading and writing. Furthermore, direct electrical stimulation of midPrCG can evoke complex movements, such as vocalization, and selective injury can cause deficits in verbal fluency, such as pure apraxia of speech. Based on these findings, we propose that midPrCG is essential to phonological-motoric aspects of speech production, especially syllabic-level speech sequencing, a role traditionally ascribed to Broca's area. The midPrCG is a cortical brain area that should be included in contemporary models of speech production with a unique role in speech motor planning and execution.
Collapse
Affiliation(s)
- Alexander B Silva
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
- Medical Scientist Training Program, University of California, San Francisco, California, 94158
- Graduate Program in Bioengineering, University of California, Berkeley, California 94720, & University of California, San Francisco, California, 94158
| | - Jessie R Liu
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
- Graduate Program in Bioengineering, University of California, Berkeley, California 94720, & University of California, San Francisco, California, 94158
| | - Lingyun Zhao
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
| | - Deborah F Levy
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
| | - Terri L Scott
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
| | - Edward F Chang
- Department of Neurological Surgery, University of California, San Francisco, California, 94158
- Weill Institute for Neurosciences, University of California, San Francisco, California, 94158
- Graduate Program in Bioengineering, University of California, Berkeley, California 94720, & University of California, San Francisco, California, 94158
| |
Collapse
|
18
|
Zhao Y, Ding S, Todoh M. Validate the force-velocity relation of the Hill's muscle model from a molecular perspective. Front Bioeng Biotechnol 2022; 10:1006571. [PMID: 36312549 PMCID: PMC9614041 DOI: 10.3389/fbioe.2022.1006571] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/30/2022] [Indexed: 07/30/2023] Open
Affiliation(s)
- Yongkun Zhao
- Division of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido University, Sapporo, Japan
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Shihang Ding
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Masahiro Todoh
- Division of Mechanical and Aerospace Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan
| |
Collapse
|
19
|
Scott M. Sensory attenuation from action observation. Exp Brain Res 2022; 240:2923-2937. [PMID: 36123539 DOI: 10.1007/s00221-022-06460-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 08/27/2022] [Indexed: 11/28/2022]
Abstract
A central claim of many embodied approaches to cognition is that understanding others' actions is achieved by covertly simulating the observed actions and their consequences in one's own motor system. If such a simulation occurs, it may be accomplished through forward models, a component of the motor system already known to perform simulations of actions and their consequences in order to support sensory-monitoring of one's own actions. Forward-model simulations cause an attenuation of sensory intensity, so if the simulations hypothesized by embodied cognition are indeed provided by forward models, then action observation should trigger this sensory attenuation. To test this hypothesis, the experiments reported here measured the perceived intensity of a touch sensation on the finger when participants observed an active touch (a finger reaching to touch a ball) vs. a passive touch (a ball rolling to touch an unmoving finger). The touch sensation was perceived as less intense during observation of active touch in comparison with observation of passive touch, providing evidence that forward models are indeed engaged during action observation. The strength of this sensory attenuation is compared and contrasted with a well-established sensory-amplification effect caused by visual attention. This sensory-amplification effect has not generally been considered in studies related to sensory attenuation in action observation, which may explain conflicting results reported in the field.
Collapse
Affiliation(s)
- Mark Scott
- Department of Psychology, Memorial University of Newfoundland, St. John's, Canada.
| |
Collapse
|
20
|
Maceira-Elvira P, Timmermann JE, Popa T, Schmid AC, Krakauer JW, Morishita T, Wessel MJ, Hummel FC. Dissecting motor skill acquisition: Spatial coordinates take precedence. SCIENCE ADVANCES 2022; 8:eabo3505. [PMID: 35857838 PMCID: PMC9299540 DOI: 10.1126/sciadv.abo3505] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Practicing a previously unknown motor sequence often leads to the consolidation of motor chunks, which enable its accurate execution at increasing speeds. Recent imaging studies suggest the function of these structures to be more related to the encoding, storage, and retrieval of sequences rather than their sole execution. We found that optimal motor skill acquisition prioritizes the storage of the spatial features of the sequence in memory over its rapid execution early in training, as proposed by Hikosaka in 1999. This process, seemingly diminished in older adults, was partially restored by anodal transcranial direct current stimulation over the motor cortex, as shown by a sharp improvement in accuracy and an earlier yet gradual emergence of motor chunks. These results suggest that the emergence of motor chunks is preceded by the storage of the sequence in memory but is not its direct consequence; rather, these structures depend on, and result from, motor practice.
Collapse
Affiliation(s)
- Pablo Maceira-Elvira
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL Valais, Clinique Romande de Réadaptation Sion, Switzerland
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL, Geneva, Switzerland
| | | | - Traian Popa
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL Valais, Clinique Romande de Réadaptation Sion, Switzerland
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL, Geneva, Switzerland
| | - Anne-Christine Schmid
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL Valais, Clinique Romande de Réadaptation Sion, Switzerland
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL, Geneva, Switzerland
| | - John W. Krakauer
- Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Takuya Morishita
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL Valais, Clinique Romande de Réadaptation Sion, Switzerland
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL, Geneva, Switzerland
| | - Maximilian J. Wessel
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL Valais, Clinique Romande de Réadaptation Sion, Switzerland
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL, Geneva, Switzerland
- Department of Neurology, University Hospital and Julius Maximilians University, Wuerzburg, Germany
| | - Friedhelm C. Hummel
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL Valais, Clinique Romande de Réadaptation Sion, Switzerland
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, EPFL, Geneva, Switzerland
- Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland
| |
Collapse
|
21
|
Goldring AB, Cooke DF, Pineda CR, Recanzone GH, Krubitzer LA. Functional characterization of the fronto-parietal reaching and grasping network: reversible deactivation of M1 and areas 2, 5, and 7b in awake behaving monkeys. J Neurophysiol 2022; 127:1363-1387. [PMID: 35417261 PMCID: PMC9109808 DOI: 10.1152/jn.00279.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 04/04/2022] [Accepted: 04/04/2022] [Indexed: 11/22/2022] Open
Abstract
In the present investigation, we examined the role of different cortical fields in the fronto-parietal reaching and grasping network in awake, behaving macaque monkeys. This network is greatly expanded in primates compared to other mammals and coevolved with glabrous hands with opposable thumbs and the extraordinary dexterous behaviors employed by a number of primates, including humans. To examine this, we reversibly deactivated the primary motor area (M1), anterior parietal area 2, and posterior parietal areas 5L and 7b individually while monkeys were performing two types of reaching and grasping tasks. Reversible deactivation was accomplished with small microfluidic thermal regulators abutting specifically targeted cortical areas. Placement of these devices in the different cortical fields was confirmed post hoc in histologically processed tissue. Our results indicate that the different areas examined form a complex network of motor control that is overlapping. However, several consistent themes emerged that suggest the independent roles that motor cortex, area 2, area 7b, and area 5L play in the motor planning and execution of reaching and grasping movements. Area 5L is involved in the early stages and area 7b the later stages of a reaching and grasping movement, motor cortex is involved in all aspects of the execution of the movement, and area 2 provides proprioceptive feedback throughout the movement. We discuss our results in the context of previous studies that explored the fronto-parietal network, the overlapping (but also independent) functions of different nodes of this network, and the rapid compensatory plasticity of this network.NEW & NOTEWORTHY This is the first study to directly compare the results of cooling different portions of the fronto-parietal reaching and grasping network (motor cortex, anterior and posterior parietal cortex) in the same animals and the first to employ a complex, bimanual reaching and grasping task that is ethologically relevant. Whereas cooling area 7b or area 5L evoked deficits at distinct task phases, cooling M1 evoked a general set of deficits and cooling area 2 evoked proprioceptive deficits.
Collapse
Affiliation(s)
- Adam B Goldring
- Department of Psychology, University of California, Davis, California
- Center for Neuroscience, University of California, Davis, California
| | - Dylan F Cooke
- Center for Neuroscience, University of California, Davis, California
- Department of Biomedical Physiology and Kinesiology (BPK), Simon Fraser University, Burnaby, British Columbia, Canada
| | - Carlos R Pineda
- Department of Psychology, University of California, Davis, California
- Center for Neuroscience, University of California, Davis, California
| | - Gregg H Recanzone
- Center for Neuroscience, University of California, Davis, California
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - Leah A Krubitzer
- Department of Psychology, University of California, Davis, California
- Center for Neuroscience, University of California, Davis, California
| |
Collapse
|
22
|
Abstract
A hallmark of adaptation in humans and other animals is our ability to control how we think and behave across different settings. Research has characterized the various forms cognitive control can take-including enhancement of goal-relevant information, suppression of goal-irrelevant information, and overall inhibition of potential responses-and has identified computations and neural circuits that underpin this multitude of control types. Studies have also identified a wide range of situations that elicit adjustments in control allocation (e.g., those eliciting signals indicating an error or increased processing conflict), but the rules governing when a given situation will give rise to a given control adjustment remain poorly understood. Significant progress has recently been made on this front by casting the allocation of control as a decision-making problem. This approach has developed unifying and normative models that prescribe when and how a change in incentives and task demands will result in changes in a given form of control. Despite their successes, these models, and the experiments that have been developed to test them, have yet to face their greatest challenge: deciding how to select among the multiplicity of configurations that control can take at any given time. Here, we will lay out the complexities of the inverse problem inherent to cognitive control allocation, and their close parallels to inverse problems within motor control (e.g., choosing between redundant limb movements). We discuss existing solutions to motor control's inverse problems drawn from optimal control theory, which have proposed that effort costs act to regularize actions and transform motor planning into a well-posed problem. These same principles may help shed light on how our brains optimize over complex control configuration, while providing a new normative perspective on the origins of mental effort.
Collapse
|
23
|
Jeschke M, Ohl FW, Wang X. Effects of Cortical Cooling on Sound Processing in Auditory Cortex and Thalamus of Awake Marmosets. Front Neural Circuits 2022; 15:786740. [PMID: 35069125 PMCID: PMC8766342 DOI: 10.3389/fncir.2021.786740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/10/2021] [Indexed: 12/15/2022] Open
Abstract
The auditory thalamus is the central nexus of bottom-up connections from the inferior colliculus and top-down connections from auditory cortical areas. While considerable efforts have been made to investigate feedforward processing of sounds in the auditory thalamus (medial geniculate body, MGB) of non-human primates, little is known about the role of corticofugal feedback in the MGB of awake non-human primates. Therefore, we developed a small, repositionable cooling probe to manipulate corticofugal feedback and studied neural responses in both auditory cortex and thalamus to sounds under conditions of normal and reduced cortical temperature. Cooling-induced increases in the width of extracellularly recorded spikes in auditory cortex were observed over the distance of several hundred micrometers away from the cooling probe. Cortical neurons displayed reduction in both spontaneous and stimulus driven firing rates with decreased cortical temperatures. In thalamus, cortical cooling led to increased spontaneous firing and either increased or decreased stimulus driven activity. Furthermore, response tuning to modulation frequencies of temporally modulated sounds and spatial tuning to sound source location could be altered (increased or decreased) by cortical cooling. Specifically, best modulation frequencies of individual MGB neurons could shift either toward higher or lower frequencies based on the vector strength or the firing rate. The tuning of MGB neurons for spatial location could both sharpen or widen. Elevation preference could shift toward higher or lower elevations and azimuth tuning could move toward ipsilateral or contralateral locations. Such bidirectional changes were observed in many parameters which suggests that the auditory thalamus acts as a filter that could be adjusted according to behaviorally driven signals from auditory cortex. Future work will have to delineate the circuit elements responsible for the observed effects.
Collapse
Affiliation(s)
- Marcus Jeschke
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States,Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany,Auditory Neuroscience and Optogenetics Group, Cognitive Hearing in Primates Laboratory, German Primate Center-Leibniz Institute for Primate Research, Göttingen, Germany,*Correspondence: Marcus Jeschke
| | - Frank W. Ohl
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany,Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Xiaoqin Wang
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States,Xiaoqin Wang
| |
Collapse
|
24
|
Kalidindi HT, Cross KP, Lillicrap TP, Omrani M, Falotico E, Sabes PN, Scott SH. Rotational dynamics in motor cortex are consistent with a feedback controller. eLife 2021; 10:e67256. [PMID: 34730516 PMCID: PMC8691841 DOI: 10.7554/elife.67256] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
Recent studies have identified rotational dynamics in motor cortex (MC), which many assume arise from intrinsic connections in MC. However, behavioral and neurophysiological studies suggest that MC behaves like a feedback controller where continuous sensory feedback and interactions with other brain areas contribute substantially to MC processing. We investigated these apparently conflicting theories by building recurrent neural networks that controlled a model arm and received sensory feedback from the limb. Networks were trained to counteract perturbations to the limb and to reach toward spatial targets. Network activities and sensory feedback signals to the network exhibited rotational structure even when the recurrent connections were removed. Furthermore, neural recordings in monkeys performing similar tasks also exhibited rotational structure not only in MC but also in somatosensory cortex. Our results argue that rotational structure may also reflect dynamics throughout the voluntary motor system involved in online control of motor actions.
Collapse
Affiliation(s)
| | - Kevin P Cross
- Centre for Neuroscience Studies, Queen's UniversityKingstonCanada
| | - Timothy P Lillicrap
- Centre for Computation, Mathematics and Physics, University College LondonLondonUnited Kingdom
| | - Mohsen Omrani
- Centre for Neuroscience Studies, Queen's UniversityKingstonCanada
| | - Egidio Falotico
- The BioRobotics Institute, Scuola Superiore Sant'AnnaPisaItaly
| | - Philip N Sabes
- Department of Physiology, University of California, San FranciscoSan FranciscoUnited States
| | - Stephen H Scott
- Centre for Neuroscience Studies, Queen's UniversityKingstonCanada
| |
Collapse
|
25
|
Lehmann SJ, Corneil BD. Completing the puzzle: Why studies in non-human primates are needed to better understand the effects of non-invasive brain stimulation. Neurosci Biobehav Rev 2021; 132:1074-1085. [PMID: 34742722 DOI: 10.1016/j.neubiorev.2021.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 09/29/2021] [Accepted: 10/31/2021] [Indexed: 11/27/2022]
Abstract
Brain stimulation is a core method in neuroscience. Numerous non-invasive brain stimulation (NIBS) techniques are currently in use in basic and clinical research, and recent advances promise the ability to non-invasively access deep brain structures. While encouraging, there is a surprising gap in our understanding of precisely how NIBS perturbs neural activity throughout an interconnected network, and how such perturbed neural activity ultimately links to behaviour. In this review, we will consider why non-human primate (NHP) models of NIBS are ideally situated to address this gap in knowledge, and why the oculomotor network that moves our line of sight offers a particularly valuable platform in which to empirically test hypothesis regarding NIBS-induced changes in brain and behaviour. NHP models of NIBS will enable investigation of the complex, dynamic effects of brain stimulation across multiple hierarchically interconnected brain areas, networks, and effectors. By establishing such links between brain and behavioural output, work in NHPs can help optimize experimental and therapeutic approaches, improve NIBS efficacy, and reduce side-effects of NIBS.
Collapse
Affiliation(s)
- Sebastian J Lehmann
- Department of Physiology and Pharmacology, Western University, London, Ontario, N6A 5B7, Canada.
| | - Brian D Corneil
- Department of Physiology and Pharmacology, Western University, London, Ontario, N6A 5B7, Canada; Department of Psychology, Western University, London, Ontario, N6A 5B7, Canada; Robarts Research Institute, London, Ontario, N6A 5B7, Canada.
| |
Collapse
|
26
|
Maurus P, Kurtzer I, Antonawich R, Cluff T. Similar stretch reflexes and behavioral patterns are expressed by the dominant and nondominant arms during postural control. J Neurophysiol 2021; 126:743-762. [PMID: 34320868 DOI: 10.1152/jn.00152.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Limb dominance is evident in many daily activities, leading to the prominent idea that each hemisphere of the brain specializes in controlling different aspects of movement. Past studies suggest that the dominant arm is primarily controlled via an internal model of limb dynamics that enables the nervous system to produce efficient movements. In contrast, the nondominant arm may be primarily controlled via impedance mechanisms that rely on the strong modulation of sensory feedback from individual joints to control limb posture. We tested whether such differences are evident in behavioral responses and stretch reflexes following sudden displacement of the arm during posture control. Experiment 1 applied specific combinations of elbow-shoulder torque perturbations (the same for all participants). Peak joint displacements, return times, end point accuracy, and the directional tuning and amplitude of stretch reflexes in nearly all muscles were not statistically different between the two arms. Experiment 2 induced specific combinations of joint motion (the same for all participants). Again, peak joint displacements, return times, end point accuracy, and the directional tuning and amplitude of stretch reflexes in nearly all muscles did not differ statistically when countering the imposed loads with each arm. Moderate to strong correlations were found between stretch reflexes and behavioral responses to the perturbations with the two arms across both experiments. Collectively, the results do not support the idea that the dominant arm specializes in exploiting internal models and the nondominant arm in impedance control by increasing reflex gains to counter sudden loads imposed on the arms during posture control.NEW & NOTEWORTHY A prominent hypothesis is that the nervous system controls the dominant arm through predictive internal models and the nondominant arm through impedance mechanisms. We tested whether stretch reflexes of muscles in the two arms also display such specialization during posture control. Nearly all behavioral responses and stretch reflexes did not differ statistically but were strongly correlated between the arms. The results indicate individual signatures of feedback control that are common for the two arms.
Collapse
Affiliation(s)
- Philipp Maurus
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Isaac Kurtzer
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York
| | - Ryan Antonawich
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York
| | - Tyler Cluff
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
27
|
Poscente SV, Peters RM, Cashaback JGA, Cluff T. Rapid Feedback Responses Parallel the Urgency of Voluntary Reaching Movements. Neuroscience 2021; 475:163-184. [PMID: 34302907 DOI: 10.1016/j.neuroscience.2021.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 11/19/2022]
Abstract
Optimal feedback control is a prominent theory used to interpret human motor behaviour. The theory posits that skilled actions emerge from control policies that link voluntary motor control (feedforward) with flexible feedback corrections (feedback control). It is clear the nervous system can generate flexible motor corrections (reflexes) when performing actions with different goals. We know little, however, about shared features of voluntary actions and feedback control in human movement. Here we reveal a link between the timing demands of voluntary actions and flexible responses to mechanical perturbations. In two experiments, 40 human participants (21 females) made reaching movements with different timing demands. We disturbed the arm with mechanical perturbations at movement onset (Experiment 1) and at locations ranging from movement onset to completion (Experiment 2). We used the resulting muscle responses and limb displacements as a proxy for the control policies that support voluntary reaching movements. We observed an increase in the sensitivity of elbow and shoulder muscle responses and a reduction in limb motion when the task imposed greater urgency to respond to the same perturbations. The results reveal a relationship between voluntary actions and feedback control as the limb was displaced less when moving faster in perturbation trials. Muscle responses scaled with changes in the displacement of the limb in perturbation trials within each timing condition. Across both experiments, human behaviour was captured by simulations based on stochastic optimal feedback control. Taken together, the results highlight flexible control that links sensory processing with features of human reaching movements.
Collapse
Affiliation(s)
- Sophia V Poscente
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Ryan M Peters
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Joshua G A Cashaback
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada; Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, USA; Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, USA; Biomechanics and Movement Science Program, University of Delaware, Newark, DE 19716, USA
| | - Tyler Cluff
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
| |
Collapse
|
28
|
Eberle H, Hayashi Y, Kurazume R, Takei T, An Q. Modeling of hyper-adaptability: from motor coordination to rehabilitation. Adv Robot 2021. [DOI: 10.1080/01691864.2021.1943710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Harry Eberle
- Department of Ortho and MSK Science Division of Surgery & Interventional Science, Faculty of Medical Sciences, University College London, London, UK
| | - Yoshikatsu Hayashi
- Biomedical Engineering, School of Biological Sciences, University of Reading, Reading, UK
| | - Ryo Kurazume
- Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan
| | - Tomohiko Takei
- Graduate School of Medicine, Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan
| | - Qi An
- Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan
| |
Collapse
|
29
|
Hausmann SB, Vargas AM, Mathis A, Mathis MW. Measuring and modeling the motor system with machine learning. Curr Opin Neurobiol 2021; 70:11-23. [PMID: 34116423 DOI: 10.1016/j.conb.2021.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/23/2021] [Accepted: 04/18/2021] [Indexed: 12/11/2022]
Abstract
The utility of machine learning in understanding the motor system is promising a revolution in how to collect, measure, and analyze data. The field of movement science already elegantly incorporates theory and engineering principles to guide experimental work, and in this review we discuss the growing use of machine learning: from pose estimation, kinematic analyses, dimensionality reduction, and closed-loop feedback, to its use in understanding neural correlates and untangling sensorimotor systems. We also give our perspective on new avenues, where markerless motion capture combined with biomechanical modeling and neural networks could be a new platform for hypothesis-driven research.
Collapse
Affiliation(s)
| | | | - Alexander Mathis
- EPFL, Swiss Federal Institute of Technology, Lausanne, Switzerland.
| | | |
Collapse
|
30
|
Mathis MW, Schneider S. Motor control: Neural correlates of optimal feedback control theory. Curr Biol 2021; 31:R356-R358. [PMID: 33848495 DOI: 10.1016/j.cub.2021.01.087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent work is revealing neural correlates of a leading theory of motor control. By linking an elegant series of behavioral experiments with neural inactivation in macaques with computational models, a new study shows that premotor and parietal areas can be mapped onto a model for optimal feedback control.
Collapse
Affiliation(s)
- Mackenzie W Mathis
- Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland.
| | - Steffen Schneider
- Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland.
| |
Collapse
|
31
|
Cheung VCK, Seki K. Approaches to revealing the neural basis of muscle synergies: a review and a critique. J Neurophysiol 2021; 125:1580-1597. [PMID: 33729869 DOI: 10.1152/jn.00625.2019] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The central nervous system (CNS) may produce coordinated motor outputs via the combination of motor modules representable as muscle synergies. Identification of muscle synergies has hitherto relied on applying factorization algorithms to multimuscle electromyographic data (EMGs) recorded during motor behaviors. Recent studies have attempted to validate the neural basis of the muscle synergies identified by independently retrieving the muscle synergies through CNS manipulations and analytic techniques such as spike-triggered averaging of EMGs. Experimental data have demonstrated the pivotal role of the spinal premotor interneurons in the synergies' organization and the presence of motor cortical loci whose stimulations offer access to the synergies, but whether the motor cortex is also involved in organizing the synergies has remained unsettled. We argue that one difficulty inherent in current approaches to probing the synergies' neural basis is that the EMG generative model based on linear combination of synergies and the decomposition algorithms used for synergy identification are not grounded on enough prior knowledge from neurophysiology. Progress may be facilitated by constraining or updating the model and algorithms with knowledge derived directly from CNS manipulations or recordings. An investigative framework based on evaluating the relevance of neurophysiologically constrained models of muscle synergies to natural motor behaviors will allow a more sophisticated understanding of motor modularity, which will help the community move forward from the current debate on the neural versus nonneural origin of muscle synergies.
Collapse
Affiliation(s)
- Vincent C K Cheung
- School of Biomedical Sciences and The Gerald Choa Neuroscience Centre, The Chinese University of Hong Kong, Hong Kong, China
| | - Kazuhiko Seki
- Department of Neurophysiology, National Institute of Neuroscience, Kodaira, Tokyo, Japan
| |
Collapse
|