1
|
Boebinger S, Payne A, Martino G, Kerr K, Mirdamadi J, McKay JL, Borich M, Ting L. Precise cortical contributions to sensorimotor feedback control during reactive balance. PLoS Comput Biol 2024; 20:e1011562. [PMID: 38630803 PMCID: PMC11057980 DOI: 10.1371/journal.pcbi.1011562] [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: 10/02/2023] [Revised: 04/29/2024] [Accepted: 03/25/2024] [Indexed: 04/19/2024] Open
Abstract
The role of the cortex in shaping automatic whole-body motor behaviors such as walking and balance is poorly understood. Gait and balance are typically mediated through subcortical circuits, with the cortex becoming engaged as needed on an individual basis by task difficulty and complexity. However, we lack a mechanistic understanding of how increased cortical contribution to whole-body movements shapes motor output. Here we use reactive balance recovery as a paradigm to identify relationships between hierarchical control mechanisms and their engagement across balance tasks of increasing difficulty in young adults. We hypothesize that parallel sensorimotor feedback loops engaging subcortical and cortical circuits contribute to balance-correcting muscle activity, and that the involvement of cortical circuits increases with balance challenge. We decomposed balance-correcting muscle activity based on hypothesized subcortically- and cortically-mediated feedback components driven by similar sensory information, but with different loop delays. The initial balance-correcting muscle activity was engaged at all levels of balance difficulty. Its onset latency was consistent with subcortical sensorimotor loops observed in the lower limb. An even later, presumed, cortically-mediated burst of muscle activity became additionally engaged as balance task difficulty increased, at latencies consistent with longer transcortical sensorimotor loops. We further demonstrate that evoked cortical activity in central midline areas measured using electroencephalography (EEG) can be explained by a similar sensory transformation as muscle activity but at a delay consistent with its role in a transcortical loop driving later cortical contributions to balance-correcting muscle activity. These results demonstrate that a neuromechanical model of muscle activity can be used to infer cortical contributions to muscle activity without recording brain activity. Our model may provide a useful framework for evaluating changes in cortical contributions to balance that are associated with falls in older adults and in neurological disorders such as Parkinson's disease.
Collapse
Affiliation(s)
- Scott Boebinger
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, United States of America
| | - Aiden Payne
- Department of Psychology, Florida State University, Tallahassee, Florida, United States of America
| | - Giovanni Martino
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Kennedy Kerr
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, United States of America
| | - Jasmine Mirdamadi
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia, United States of America
| | - J. Lucas McKay
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, United States of America
- Departments of Biomedical Informatics and Neurology, Emory University, Atlanta, Georgia, United States of America
| | - Michael Borich
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, United States of America
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia, United States of America
| | - Lena Ting
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, United States of America
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia, United States of America
| |
Collapse
|
2
|
Witts EC, Mathews MA, Murray AJ. The locus coeruleus directs sensory-motor reflex amplitude across environmental contexts. Curr Biol 2023; 33:4679-4688.e3. [PMID: 37741282 PMCID: PMC10957397 DOI: 10.1016/j.cub.2023.08.085] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/03/2023] [Accepted: 08/25/2023] [Indexed: 09/25/2023]
Abstract
Purposeful movement across unpredictable environments requires quick, accurate, and contextually appropriate motor corrections in response to disruptions in balance and posture.1,2,3 These responses must respect both the current position and limitations of the body, as well as the surrounding environment,4,5,6 and involve a combination of segmental reflexes in the spinal cord, vestibulospinal and reticulospinal pathways in the brainstem, and forebrain structures such as the motor cortex.7,8,9,10 These motor plans can be heavily influenced by the animal's surrounding environment, even when that environment has no mechanical influence on the perturbation itself. This environmental influence has been considered as cortical in nature, priming motor responses to a perturbation.8,11 Similarly, postural responses can be influenced by environments that alter threat levels in humans.12,13,14,15,16,17,18 Such studies are generally in agreement with work done in the mouse showing that optogenetic stimulation of the lateral vestibular nucleus (LVN) only results in motor responses when the animal is on a balance beam at height and not when walking on the stable surface of a treadmill.10 In general, this ability to flexibly modify postural responses across terrains and environmental conditions is a critically important component of the balance system.19,20 Here we show that LVN-generated motor corrections can be altered by manipulating the surrounding environment. Furthermore, environmental influence on corrections requires noradrenergic signaling from the locus coeruleus, suggesting a potential link between forebrain structures that convey sensory information about the environment and brainstem circuits that generate motor corrections.
Collapse
Affiliation(s)
- Emily C Witts
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, W1T 4JG London, UK.
| | - Miranda A Mathews
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, W1T 4JG London, UK
| | - Andrew J Murray
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, W1T 4JG London, UK.
| |
Collapse
|
3
|
A Comparison of Left and Right Leg Static Balance Parameters in Young Handball Players. JOURNAL OF BASIC AND CLINICAL HEALTH SCIENCES 2022. [DOI: 10.30621/jbachs.1059392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
4
|
Nandakumar B, Blumenthal GH, Pauzin FP, Moxon KA. Hindlimb Somatosensory Information Influences Trunk Sensory and Motor Cortices to Support Trunk Stabilization. Cereb Cortex 2021; 31:5165-5187. [PMID: 34165153 DOI: 10.1093/cercor/bhab150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/10/2021] [Accepted: 04/27/2021] [Indexed: 11/14/2022] Open
Abstract
Sensorimotor integration in the trunk system is poorly understood despite its importance for functional recovery after neurological injury. To address this, a series of mapping studies were performed in the rat. First, the receptive fields (RFs) of cells recorded from thoracic dorsal root ganglia were identified. Second, the RFs of cells recorded from trunk primary sensory cortex (S1) were used to assess the extent and internal organization of trunk S1. Finally, the trunk motor cortex (M1) was mapped using intracortical microstimulation to assess coactivation of trunk muscles with hindlimb and forelimb muscles, and integration with S1. Projections from trunk S1 to trunk M1 were not anatomically organized, with relatively weak sensorimotor integration between trunk S1 and M1 compared to extensive integration between hindlimb S1/M1 and trunk M1. Assessment of response latency and anatomical tracing suggest that trunk M1 is abundantly guided by hindlimb somatosensory information that is derived primarily from the thalamus. Finally, neural recordings from awake animals during unexpected postural perturbations support sensorimotor integration between hindlimb S1 and trunk M1, providing insight into the role of the trunk system in postural control that is useful when studying recovery after injury.
Collapse
Affiliation(s)
- Bharadwaj Nandakumar
- Department of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, 19104 PA, USA.,Department of Biomedical Engineering, University of California, Davis, 95616 CA, USA
| | - Gary H Blumenthal
- Department of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, 19104 PA, USA.,Department of Biomedical Engineering, University of California, Davis, 95616 CA, USA
| | | | - Karen A Moxon
- Department of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, 19104 PA, USA.,Department of Biomedical Engineering, University of California, Davis, 95616 CA, USA.,Center for Neuroscience, Davis, 95618 CA, USA
| |
Collapse
|
5
|
Rudroff T, Workman CD. Transcranial Direct Current Stimulation as a Treatment Tool for Mild Traumatic Brain Injury. Brain Sci 2021; 11:brainsci11060806. [PMID: 34207004 PMCID: PMC8235194 DOI: 10.3390/brainsci11060806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 11/16/2022] Open
Abstract
Mild traumatic brain injury (mTBI) has been defined as a transient (<24 h) condition of confusion and/or loss of consciousness for less than 30 min after brain injury and can result in short- and long-term motor and cognitive impairments. Recent studies have documented the therapeutic potential of non-invasive neuromodulation techniques for the enhancement of cognitive and motor function in mTBI. Alongside repetitive transcranial magnetic stimulation (rTMS), the main technique used for this purpose is transcranial direct current stimulation (tDCS). The focus of this review was to provide a detailed, comprehensive (i.e., both cognitive and motor impairment) overview of the literature regarding therapeutic tDCS paradigms after mTBI. A publication search of the PubMed, Scopus, CINAHL, and PsycINFO databases was performed to identify records that applied tDCS in mTBI. The publication search yielded 14,422 records from all of the databases, however, only three met the inclusion criteria and were included in the final review. Based on the review, there is limited evidence of tDCS improving cognitive and motor performance. Surprisingly, there were only three studies that used tDCS in mTBI, which highlights an urgent need for more research to provide additional insights into ideal therapeutic brain targets and optimized stimulation parameters.
Collapse
Affiliation(s)
- Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA;
- Department of Neurology, University of Iowa Health Clinics, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-319-467-0363
| | - Craig D. Workman
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA;
| |
Collapse
|
6
|
Park G, Suh JH, Han SJ. Transcranial direct current stimulation for balance and gait in repetitive mild traumatic brain injury in rats. BMC Neurosci 2021; 22:26. [PMID: 33865318 PMCID: PMC8052850 DOI: 10.1186/s12868-021-00633-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/06/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Balance impairment and lack of postural orientation are serious problems in patients with repetitive mild traumatic brain injury (mTBI). OBJECTIVE To investigate whether anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) can improve balance control and gait in repetitive mTBI rat models. METHODS In this prospective animal study, 65 repetitive mTBI rats were randomly assigned to two groups: the tDCS group and the control group. To create repetitive mTBI model rats, we induced mTBI in the rats for 3 consecutive days. The tDCS group received one session of anodal tDCS over the M1 area 24 h after the third induced mTBI, while the control group did not receive tDCS treatment. Motor-evoked potential (MEP), foot-fault test, and rotarod test were evaluated before mTBI, before tDCS and after tDCS. The Mann-Whitney U test and Wilcoxon signed rank test were used to assess the effects of variables between the two groups. RESULTS Anodal tDCS over the M1 area significantly improved the amplitude of MEP in the tDCS group (p = 0.041). In addition, rotarod duration was significantly increased in the tDCS group (p = 0.001). The foot-fault ratio was slightly lower in the tDCS group, however, this was not statistically significant. CONCLUSION Anodal tDCS at the M1 area could significantly improve the amplitude of MEP and balance function in a repetitive mTBI rat model. We expect that anodal tDCS would have the potential to improve balance in patients with repetitive mTBI.
Collapse
Affiliation(s)
- Gahee Park
- Department of Rehabilitation Medicine, College of Medicine, Ewha Womans University, 1071 An-Yang-Cheon Ro, Yang-Cheon Gu, Seoul, 07985, Republic of Korea
| | - Jee Hyun Suh
- Department of Rehabilitation Medicine, College of Medicine, Ewha Womans University, 1071 An-Yang-Cheon Ro, Yang-Cheon Gu, Seoul, 07985, Republic of Korea. .,Department of Rehabilitation Medicine, Bundang Jesaeng General Hospital, 20, Seohyeon-ro 180 beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13590, Republic of Korea.
| | - Soo Jeong Han
- Department of Rehabilitation Medicine, College of Medicine, Ewha Womans University, 1071 An-Yang-Cheon Ro, Yang-Cheon Gu, Seoul, 07985, Republic of Korea
| |
Collapse
|
7
|
Ghosn NJ, Palmer JA, Borich MR, Ting LH, Payne AM. Cortical Beta Oscillatory Activity Evoked during Reactive Balance Recovery Scales with Perturbation Difficulty and Individual Balance Ability. Brain Sci 2020; 10:E860. [PMID: 33207570 PMCID: PMC7697848 DOI: 10.3390/brainsci10110860] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/06/2020] [Accepted: 11/12/2020] [Indexed: 11/16/2022] Open
Abstract
Cortical beta oscillations (13-30 Hz) reflect sensorimotor processing, but are not well understood in balance recovery. We hypothesized that sensorimotor cortical activity would increase under challenging balance conditions. We predicted greater beta power when balance was challenged, either by more difficult perturbations or by lower balance ability. In 19 young adults, we measured beta power over motor cortical areas (electroencephalography, Cz electrode) during three magnitudes of backward support -surface translations. Peak beta power was measured during early (50-150 ms), late (150-250 ms), and overall (0-400 ms) time bins, and wavelet-based analyses quantified the time course of evoked beta power. An ANOVA was used to compare peak beta power across perturbation magnitudes in each time bin. We further tested the association between perturbation-evoked beta power and individual balance ability measured in a challenging beam walking task. Beta power increased ~50 ms after perturbation, and to a greater extent in larger perturbations. Lower individual balance ability was associated with greater beta power in only the late (150-250 ms) time bin. These findings demonstrate greater sensorimotor cortical engagement under more challenging balance conditions, which may provide a biomarker for reduced automaticity in balance control that could be used in populations with neurological impairments.
Collapse
Affiliation(s)
- Nina J. Ghosn
- Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | | | - Michael R. Borich
- Emory University, Atlanta, GA 30332, USA; (J.A.P.); (M.R.B.); (L.H.T.)
| | - Lena H. Ting
- Emory University, Atlanta, GA 30332, USA; (J.A.P.); (M.R.B.); (L.H.T.)
| | - Aiden M. Payne
- Emory University, Atlanta, GA 30332, USA; (J.A.P.); (M.R.B.); (L.H.T.)
| |
Collapse
|
8
|
Guillaud E, Seyres P, Barrière G, Jecko V, Bertrand SS, Cazalets JR. Locomotion and dynamic posture: neuro-evolutionary basis of bipedal gait. Neurophysiol Clin 2020; 50:467-477. [PMID: 33176989 DOI: 10.1016/j.neucli.2020.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/23/2020] [Accepted: 10/23/2020] [Indexed: 12/24/2022] Open
Abstract
Body displacement during locomotion is a major challenge for motor control, requiring complex synergistic postural regulation and the integrated functioning of all body musculature, including that of the four limbs, trunk and neck. Despite the obvious pivotal role played by the trunk during locomotion, most studies devoted to understanding the neural basis of locomotor control have only addressed the operation of the neural circuits driving leg movements, and relatively little is known of the networks that control trunk muscles in limbed vertebrates. This review addresses this issue, both in animals and humans. We first review studies addressing the central role played by central pattern generator (CPG) circuit interactions within the spinal cord in coordinating trunk and hind limb muscle activities in a variety of vertebrates, and present evidence that vestibulo-spinal reflexes are differentially involved in trunk and hind limb control. We finally highlight the role of the various components that participate in maintaining dynamic equilibrium during stepping, including connective tissues. We propose that many aspects of the organization of the motor systems involved in trunk-hind limb movement control in vertebrates have been highly conserved throughout evolution.
Collapse
Affiliation(s)
- Etienne Guillaud
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Philippe Seyres
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Gregory Barrière
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Vincent Jecko
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Sandrine S Bertrand
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Jean-René Cazalets
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France.
| |
Collapse
|
9
|
Bhatt T, Patel P, Dusane S, DelDonno SR, Langenecker SA. Neural Mechanisms Involved in Mental Imagery of Slip-Perturbation While Walking: A Preliminary fMRI Study. Front Behav Neurosci 2018; 12:203. [PMID: 30319366 PMCID: PMC6168704 DOI: 10.3389/fnbeh.2018.00203] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 08/16/2018] [Indexed: 11/21/2022] Open
Abstract
Background: Behavioral evidence for cortical involvement in reactive balance control in response to environmental perturbation is established, however, the neural correlates are not known. This study aimed to examine the neural mechanisms involved in reactive balance control for recovery from slip-like perturbations using mental imagery and to evaluate the difference in activation patterns between imagined and observed slipping. Methods: Ten healthy young participants after an exposure to regular walking and slip-perturbation trial on a treadmill, performed mental imagery and observation tasks in the MR scanner. Participants received verbal instructions to imagine walking (IW), observe walking (OW), imagine slipping (IS) and observe slipping (OS) while walking. Results: Analysis using general linear model showed increased activation during IS versus IW condition in precentral gyrus, middle frontal gyrus, superior, middle and transverse temporal gyrus, parahippocampal gyrus, cingulate gyrus, insula, pulvinar nucleus of the thalamus, pons, anterior and posterior cerebellar lobes. During IS versus OS condition, there was additional activation in parahippocampus, cingulate gyrus, inferior parietal lobule, superior temporal, middle and inferior frontal gyrus. Conclusion: The findings of the current study support involvement of higher cortical and subcortical structures in reactive balance control. Greater activation during slipping could be attributed to the complexity of the sensorimotor task and increased demands to maintain postural stability during slipping as compared with regular walking. Furthermore, our findings suggest that mental imagery of slipping recruited greater neural substrates rather than observation of slipping, possibly due to increased sensory, cognitive and perceptual processing demands. New and Noteworthy: The behavioral factors contributing to falls from external perturbations while walking are better understood than neural mechanisms underlying the behavioral response. This study examines the neural activation pattern associated with reactive balance control during slip-like perturbations while walking through an fMRI paradigm. This study identified specific neural mechanisms involved in complex postural movements during sudden perturbations, to particularly determine the role of cortical structures in reactive balance control. It further highlights the specific differences in neural structures involved in regular unperturbed versus perturbed walking.
Collapse
Affiliation(s)
- Tanvi Bhatt
- Department of Physical Therapy, College of Applied Health Sciences, Chicago, IL, United States
| | - Prakruti Patel
- Department of Physical Therapy, College of Applied Health Sciences, Chicago, IL, United States
| | - Shamali Dusane
- Department of Physical Therapy, College of Applied Health Sciences, Chicago, IL, United States
| | - Sophie R. DelDonno
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Scott A. Langenecker
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| |
Collapse
|
10
|
Development of vestibular behaviors in zebrafish. Curr Opin Neurobiol 2018; 53:83-89. [PMID: 29957408 DOI: 10.1016/j.conb.2018.06.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 01/09/2023]
Abstract
Most animals orient their bodies with respect to gravity to facilitate locomotion and perception. The neural circuits responsible for these orienting movements have long served as a model to address fundamental questions in systems neuroscience. Though postural control is vital, we know little about development of either balance reflexes or the neural circuitry that produces them. Recent work in a genetically and optically accessible vertebrate, the larval zebrafish, has begun to reveal the mechanisms by which such vestibular behaviors and circuits come to function. Here we highlight recent work that leverages the particular advantages of the larval zebrafish to illuminate mechanisms of postural development, the role of sensation for balance circuit development, and the organization of developing vestibular circuits. Further, we frame open questions regarding the developmental mechanisms for functional circuit assembly and maturation where studying the zebrafish vestibular system is likely to open new frontiers.
Collapse
|
11
|
Varghese JP, McIlroy RE, Barnett-Cowan M. Perturbation-evoked potentials: Significance and application in balance control research. Neurosci Biobehav Rev 2017; 83:267-280. [PMID: 29107828 DOI: 10.1016/j.neubiorev.2017.10.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/16/2017] [Accepted: 10/24/2017] [Indexed: 01/23/2023]
Abstract
Historically, balance control was thought to be mediated solely by subcortical structures based on animal research. However, recent findings provide compelling evidence of cortical involvement during balance reactions evoked by whole-body postural perturbations. In humans, an external perturbation elicits an evoked potential, termed the perturbation-evoked potential (PEP). PEPs are widely distributed over fronto-centro-parietal areas with maximal amplitude at the FCz/Cz electrode. From our literature review it is evident that the PEPs are comprised of a small positive potential (P1) that peaks around 30-90ms after perturbation onset, a large negative potential (N1) that peaks around 90-160ms, followed by positive (P2) and negative (N2) potentials between 200 and 400ms. Converging results across multiple studies suggest that these different PEP components are influenced by perturbation characteristics, postural set, environmental, and psychological factors. This review summarizes and integrates seminal research on the PEP, with a special emphasis on the PEP N1. Implications for future studies in PEP research are discussed to encourage further empirical investigation of PEP characteristics in healthy and patient populations.
Collapse
Affiliation(s)
- Jessy Parokaran Varghese
- Department of Kinesiology, University of Waterloo, 200 University Ave W, Waterloo, Ontario, N2L 3G1, Canada
| | - Robert E McIlroy
- Department of Kinesiology, University of Waterloo, 200 University Ave W, Waterloo, Ontario, N2L 3G1, Canada
| | - Michael Barnett-Cowan
- Department of Kinesiology, University of Waterloo, 200 University Ave W, Waterloo, Ontario, N2L 3G1, Canada
| |
Collapse
|
12
|
Cebolla AM, Petieau M, Dan B, Balazs L, McIntyre J, Cheron G. "Cerebellar contribution to visuo-attentional alpha rhythm: insights from weightlessness". Sci Rep 2016; 6:37824. [PMID: 27883068 PMCID: PMC5121637 DOI: 10.1038/srep37824] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/02/2016] [Indexed: 11/23/2022] Open
Abstract
Human brain adaptation in weightlessness follows the necessity to reshape the dynamic integration of the neural information acquired in the new environment. This basic aspect was here studied by the electroencephalogram (EEG) dynamics where oscillatory modulations were measured during a visuo-attentional state preceding a visuo-motor docking task. Astronauts in microgravity conducted the experiment in free-floating aboard the International Space Station, before the space flight and afterwards. We observed stronger power decrease (~ERD: event related desynchronization) of the ~10 Hz oscillation from the occipital-parietal (alpha ERD) to the central areas (mu ERD). Inverse source modelling of the stronger alpha ERD revealed a shift from the posterior cingulate cortex (BA31, from the default mode network) on Earth to the precentral cortex (BA4, primary motor cortex) in weightlessness. We also observed significant contribution of the vestibular network (BA40, BA32, and BA39) and cerebellum (lobule V, VI). We suggest that due to the high demands for the continuous readjustment of an appropriate body posture in free-floating, this visuo-attentional state required more contribution from the motor cortex. The cerebellum and the vestibular network involvement in weightlessness might support the correction signals processing necessary for postural stabilization, and the increased demand to integrate incongruent vestibular information.
Collapse
Affiliation(s)
- A. M. Cebolla
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - M. Petieau
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - B. Dan
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Inkendaal Rehabilitation Hospital, 1602 Vlezenbeek, Belgium
| | - L. Balazs
- Institute for Psychology of the Hungarian Academy of Sciences, Department of Experimental Psychology, 1132 Budapest, Hungary
| | - J. McIntyre
- LNRS/CNRS-Université René Descartes Paris V, 75006, Paris, France
| | - G. Cheron
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Laboratory of Electrophysiology, Université de Mons, 7000 Mons, Belgium
| |
Collapse
|
13
|
Musculoskeletal modeling of human lower limb during normal walking, one-legged forward hopping and side jumping: Comparison of measured EMG and predicted muscle activity patterns. J Biomech 2016; 49:3660-3666. [DOI: 10.1016/j.jbiomech.2016.09.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 09/22/2016] [Accepted: 09/30/2016] [Indexed: 11/23/2022]
|
14
|
Role of brain hemispheric dominance in anticipatory postural control strategies. Exp Brain Res 2016; 234:1997-2005. [DOI: 10.1007/s00221-016-4603-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 02/18/2016] [Indexed: 11/26/2022]
|
15
|
Bionic Control of Cheetah Bounding with a Segmented Spine. Appl Bionics Biomech 2016; 2016:5031586. [PMID: 27065749 PMCID: PMC4808829 DOI: 10.1155/2016/5031586] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 11/25/2022] Open
Abstract
A cheetah model is built to mimic real cheetah and its mechanical and dimensional parameters are derived from the real cheetah. In particular, two joints in spine and four joints in a leg are used to realize the motion of segmented spine and segmented legs which are the key properties of the cheetah bounding. For actuating and stabilizing the bounding gait of cheetah, we present a bioinspired controller based on the state-machine. The controller mainly mimics the function of the cerebellum to plan the locomotion and keep the body balance. The haptic sensor and proprioception system are used to detect the trigger of the phase transition. Besides, the vestibular modulation could perceive the pitching angle of the trunk. At last, the cerebellum acts as the CPU to operate the information from the biological sensors. In addition, the calculated results are transmitted to the low-level controller to actuate and stabilize the cheetah bounding. Moreover, the delay feedback control method is employed to plan the motion of the leg joints to stabilize the pitching motion of trunk with the stability criterion. Finally, the cyclic cheetah bounding with biological properties is realized. Meanwhile, the stability and dynamic properties of the cheetah bounding gait are analyzed elaborately.
Collapse
|
16
|
Poortvliet PC, Tucker KJ, Finnigan S, Scott D, Sowman P, Hodges PW. Cortical activity differs between position- and force-control knee extension tasks. Exp Brain Res 2015; 233:3447-57. [DOI: 10.1007/s00221-015-4404-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 08/03/2015] [Indexed: 11/24/2022]
|
17
|
Patel P, Bhatt T. Adaptation to large-magnitude treadmill-based perturbations: improvements in reactive balance response. Physiol Rep 2015; 3:3/2/e12247. [PMID: 25649245 PMCID: PMC4393185 DOI: 10.14814/phy2.12247] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We aimed to examine the trial-to-trial changes in the reactive balance response to large magnitude slip-like treadmill perturbations in stance and whether the acquired adaptive changes could be appropriately scaled to a higher intensity perturbation. Seventeen young adults experienced 15 slips for training on level I intensity. Pre- and post-training slips were delivered at a higher intensity (20% > level I). Pre- and post-slip onset stability (at liftoff and touchdown of stepping limb) was measured as the shortest distance of the center of mass (COM) position (XCOM/BOS) and velocity (ẊCOM/BOS) relative to base of support (BOS) from a predicted threshold for backward loss of balance. The number of steps to recover balance, compensatory step length and peak trunk angle were recorded. The post-slip onset stability (at liftoff and touchdown) significantly increased across the trials with no change in preslip stability. Improvement in stability at touchdown positively correlated with an anterior shift in XCOM/BOS but not with ẊCOM/BOS. Consequently, the number of steps required to recover balance declined. The adaptive change in XCOM/BOS resulted from an increase in compensatory step length and reduced trunk extension. Individuals also improved post-slip onset stability on a higher intensity perturbation post-training compared with the pre-training trial. The results support that the CNS adapts to fixed intensity slip-like perturbations primarily by improving the reactive stability via modulation in compensatory step length and trunk extension. Furthermore, based on prior experience from the training phase, the acquired adaptive response can be successfully calibrated to a higher intensity perturbation.
Collapse
Affiliation(s)
- Prakruti Patel
- Department of Physical Therapy, University of Illinois at Chicago, 1919 W, Taylor Street, 4th Floor., Chicago, 60612, Illinois
| | - Tanvi Bhatt
- Department of Physical Therapy, University of Illinois at Chicago, 1919 W, Taylor Street, 4th Floor., Chicago, 60612, Illinois
| |
Collapse
|
18
|
Fisher AR, Bacon CJ, Mannion JVH. The effect of cervical spine manipulation on postural sway in patients with nonspecific neck pain. J Manipulative Physiol Ther 2014; 38:65-73. [PMID: 25467613 DOI: 10.1016/j.jmpt.2014.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 08/25/2014] [Accepted: 09/01/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This crossover study aimed to determine whether a single high-velocity, low-amplitude manipulation of the cervical spine would affect postural sway in adults with nonspecific neck pain. METHODS Ten participants received, in random order, 7 days apart, a high-velocity, low-amplitude manipulation applied to a dysfunctional spinal segment and a passive head-movement control. Four parameters of postural sway were measured before, immediately after, and at 5 and 10 minutes after each procedure. RESULTS Results showed no differences between interventions in change in any of the parameters. When changes before and immediately after each procedure were analyzed separately, only the control showed a significant change in the length of center of pressure path (an increase from median, 118 mm; interquartlie range, 93-137 mm to an increase to 132 mm; 112-147; P = .02). CONCLUSION This study failed to show evidence that single manipulation of the cervical spine influenced postural sway. Given the ability of the postural control system to reweight the hierarchy of sensory information to compensate for inadequacies in any 1 component, it is possible that any improvements in the mechanisms controlling postural sway elicited by the manipulative intervention may have been concealed.
Collapse
Affiliation(s)
- Alison R Fisher
- Osteopath, Department of Osteopathy, Unitec Institute of Technology, Auckland, New Zealand
| | - Catherine J Bacon
- Research Supervisor, Department of Osteopathy, Unitec Institute of Technology, Auckland, New Zealand; Postdoctoral Research Fellow, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Jamie V H Mannion
- Lecturer, Department of Osteopathy, Unitec Institute of Technology, Auckland, New Zealand
| |
Collapse
|
19
|
Farrell BJ, Bulgakova MA, Beloozerova IN, Sirota MG, Prilutsky BI. Body stability and muscle and motor cortex activity during walking with wide stance. J Neurophysiol 2014; 112:504-24. [PMID: 24790167 PMCID: PMC4122701 DOI: 10.1152/jn.00064.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/23/2014] [Indexed: 11/22/2022] Open
Abstract
Biomechanical and neural mechanisms of balance control during walking are still poorly understood. In this study, we examined the body dynamic stability, activity of limb muscles, and activity of motor cortex neurons [primarily pyramidal tract neurons (PTNs)] in the cat during unconstrained walking and walking with a wide base of support (wide-stance walking). By recording three-dimensional full-body kinematics we found for the first time that during unconstrained walking the cat is dynamically unstable in the forward direction during stride phases when only two diagonal limbs support the body. In contrast to standing, an increased lateral between-paw distance during walking dramatically decreased the cat's body dynamic stability in double-support phases and prompted the cat to spend more time in three-legged support phases. Muscles contributing to abduction-adduction actions had higher activity during stance, while flexor muscles had higher activity during swing of wide-stance walking. The overwhelming majority of neurons in layer V of the motor cortex, 82% and 83% in the forelimb and hindlimb representation areas, respectively, were active differently during wide-stance walking compared with unconstrained condition, most often by having a different depth of stride-related frequency modulation along with a different mean discharge rate and/or preferred activity phase. Upon transition from unconstrained to wide-stance walking, proximal limb-related neuronal groups subtly but statistically significantly shifted their activity toward the swing phase, the stride phase where most of body instability occurs during this task. The data suggest that the motor cortex participates in maintenance of body dynamic stability during locomotion.
Collapse
Affiliation(s)
- Brad J Farrell
- School of Applied Physiology, Center for Human Movement Studies, Georgia Institute of Technology, Atlanta, Georgia; and
| | - Margarita A Bulgakova
- School of Applied Physiology, Center for Human Movement Studies, Georgia Institute of Technology, Atlanta, Georgia; and Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Irina N Beloozerova
- Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Mikhail G Sirota
- Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Boris I Prilutsky
- School of Applied Physiology, Center for Human Movement Studies, Georgia Institute of Technology, Atlanta, Georgia; and
| |
Collapse
|
20
|
Barter JW, Castro S, Sukharnikova T, Rossi MA, Yin HH. The role of the substantia nigra in posture control. Eur J Neurosci 2014; 39:1465-73. [PMID: 24628921 DOI: 10.1111/ejn.12540] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/13/2014] [Accepted: 02/03/2014] [Indexed: 11/26/2022]
Abstract
Disorders implicating the basal ganglia are often characterized by postural deficits, but little is known about the role of the basal ganglia in posture control. Using wireless multi-electrode recording, we measured single unit activity from GABAergic and dopaminergic neurons in the substantia nigra as unrestrained mice stood on an elevated platform while introducing continuous postural disturbances in the roll plane. We found two major types of neurons - those activated by tilt to the left side of the body and suppressed by tilt to the right side, and others activated by tilt to the right side and suppressed by tilt to the left side. Contrary to the prevailing view that the basal ganglia output from the substantia nigra pars reticulata either inhibits or disinhibits downstream structures in an all or none fashion, we showed that it continuously sends anti-phase signals to their downstream targets. We also demonstrated for the first time that nigrostriatal dopaminergic transmission is modulated by postural disturbances.
Collapse
Affiliation(s)
- Joseph W Barter
- Department of Psychology and Neuroscience, Duke University, Durham, NC, 27708, USA; Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
| | | | | | | | | |
Collapse
|
21
|
Bolton DAE, Williams L, Staines WR, McIlroy WE. Contribution of primary motor cortex to compensatory balance reactions. BMC Neurosci 2012; 13:102. [PMID: 22898241 PMCID: PMC3502544 DOI: 10.1186/1471-2202-13-102] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 07/31/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rapid compensatory arm reactions represent important response strategies following an unexpected loss of balance. While it has been assumed that early corrective actions arise largely from sub-cortical networks, recent findings have prompted speculation about the potential role of cortical involvement. To test the idea that cortical motor regions are involved in early compensatory arm reactions, we used continuous theta burst stimulation (cTBS) to temporarily suppress the hand area of primary motor cortex (M1) in participants prior to evoking upper limb balance reactions in response to whole body perturbation. We hypothesized that following cTBS to the M1 hand area evoked EMG responses in the stimulated hand would be diminished. To isolate balance reactions to the upper limb participants were seated in an elevated tilt-chair while holding a stable handle with both hands. The chair was held vertical by a magnet and was triggered to fall backward unpredictably. To regain balance, participants used the handle to restore upright stability as quickly as possible with both hands. Muscle activity was recorded from proximal and distal muscles of both upper limbs. RESULTS Our results revealed an impact of cTBS on the amplitude of the EMG responses in the stimulated hand muscles often manifest as inhibition in the stimulated hand. The change in EMG amplitude was specific to the target hand muscles and occasionally their homologous pairs on the non-stimulated hand with no consistent effects on the remaining more proximal arm muscles. CONCLUSIONS Present findings offer support for cortical contributions to the control of early compensatory arm reactions following whole-body perturbation.
Collapse
Affiliation(s)
- David A E Bolton
- Department of Kinesiology, University of Waterloo, 200 University Avenue W, Waterloo, ON, N2L 3 G1, Canada.
| | | | | | | |
Collapse
|
22
|
Roh J, Cheung VCK, Bizzi E. Modules in the brain stem and spinal cord underlying motor behaviors. J Neurophysiol 2011; 106:1363-78. [PMID: 21653716 PMCID: PMC3174810 DOI: 10.1152/jn.00842.2010] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 06/03/2011] [Indexed: 12/28/2022] Open
Abstract
Previous studies using intact and spinalized animals have suggested that coordinated movements can be generated by appropriate combinations of muscle synergies controlled by the central nervous system (CNS). However, which CNS regions are responsible for expressing muscle synergies remains an open question. We address whether the brain stem and spinal cord are involved in expressing muscle synergies used for executing a range of natural movements. We analyzed the electromyographic (EMG) data recorded from frog leg muscles before and after transection at different levels of the neuraxis-rostral midbrain (brain stem preparations), rostral medulla (medullary preparations), and the spinal-medullary junction (spinal preparations). Brain stem frogs could jump, swim, kick, and step, while medullary frogs could perform only a partial repertoire of movements. In spinal frogs, cutaneous reflexes could be elicited. Systematic EMG analysis found two different synergy types: 1) synergies shared between pre- and posttransection states and 2) synergies specific to individual states. Almost all synergies found in natural movements persisted after transection at rostral midbrain or medulla but not at the spinal-medullary junction for swim and step. Some pretransection- and posttransection-specific synergies for a certain behavior appeared as shared synergies for other motor behaviors of the same animal. These results suggest that the medulla and spinal cord are sufficient for the expression of most muscle synergies in frog behaviors. Overall, this study provides further evidence supporting the idea that motor behaviors may be constructed by muscle synergies organized within the brain stem and spinal cord and activated by descending commands from supraspinal areas.
Collapse
Affiliation(s)
- Jinsook Roh
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
| | | | | |
Collapse
|
23
|
Bingham JT, Choi JT, Ting LH. Stability in a frontal plane model of balance requires coupled changes to postural configuration and neural feedback control. J Neurophysiol 2011; 106:437-48. [PMID: 21543754 DOI: 10.1152/jn.00010.2011] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Postural stability depends on interactions between the musculoskeletal system and neural control mechanisms. We present a frontal plane model stabilized by delayed feedback to analyze the effects of altered stance width on postural responses to perturbations. We hypothesized that changing stance width alters the mechanical dynamics of the body and limits the range of delayed feedback gains that produce stable postural behaviors. Surprisingly, mechanical stability was found to decrease as stance width increased due to decreased effective inertia. Furthermore, due to sensorimotor delays and increased leverage of hip joint torque on center-of-mass motion, the magnitudes of the stabilizing delayed feedback gains decreased as stance width increased. Moreover, the ranges of the stable feedback gains were nonoverlapping across different stance widths such that using a single neural feedback control strategy at both narrow and wide stances could lead to instability. The set of stable feedback gains was further reduced by constraints on foot lift-off and perturbation magnitude. Simulations were fit to experimentally measured kinematics, and the identified feedback gains corroborated model predictions. In addition, analytical gain margin of the linearized system was found to predict step transitions without the need for simulation. In conclusion, this model offers a method to dissociate the complex interactions between postural configuration, delayed sensorimotor feedback, and nonlinear foot lift-off constraints. The model demonstrates that stability at wide stances can only be achieved if delayed neural feedback gains decrease. This model may be useful in explaining both expected and paradoxical changes in stance width in healthy and neurologically impaired individuals.
Collapse
Affiliation(s)
- Jeffrey T Bingham
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | | |
Collapse
|
24
|
Bunderson NE, McKay JL, Ting LH, Burkholder TJ. Directional constraint of endpoint force emerges from hindlimb anatomy. ACTA ACUST UNITED AC 2010; 213:2131-41. [PMID: 20511528 DOI: 10.1242/jeb.037879] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Postural control requires the coordination of force production at the limb endpoints to apply an appropriate force to the body. Subjected to horizontal plane perturbations, quadruped limbs stereotypically produce force constrained along a line that passes near the center of mass. This phenomenon, referred to as the force constraint strategy, may reflect mechanical constraints on the limb or body, a specific neural control strategy or an interaction among neural controls and mechanical constraints. We used a neuromuscular model of the cat hindlimb to test the hypothesis that the anatomical constraints restrict the mechanical action of individual muscles during stance and constrain the response to perturbations to a line independent of perturbation direction. In a linearized neuromuscular model of the cat hindlimb, muscle lengthening directions were highly conserved across 10,000 different muscle activation patterns, each of which produced an identical, stance-like endpoint force. These lengthening directions were closely aligned with the sagittal plane and reveal an anatomical structure for directionally constrained force responses. Each of the 10,000 activation patterns was predicted to produce stable stance based on Lyapunov stability analysis. In forward simulations of the nonlinear, seven degree of freedom model under the action of 200 random muscle activation patterns, displacement of the endpoint from its equilibrium position produced restoring forces, which were also biased toward the sagittal plane. The single exception was an activation pattern based on minimum muscle stress optimization, which produced destabilizing force responses in some perturbation directions. The sagittal force constraint increased during simulations as the system shifted from an inertial response during the acceleration phase to a viscoelastic response as peak velocity was obtained. These results qualitatively match similar experimental observations and suggest that the force constraint phenomenon may result from the anatomical arrangement of the limb.
Collapse
Affiliation(s)
- Nathan E Bunderson
- Neural Engineering Center for Artificial Limbs, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA
| | | | | | | |
Collapse
|
25
|
Brocard F, Ryczko D, Fénelon K, Hatem R, Gonzales D, Auclair F, Dubuc R. The transformation of a unilateral locomotor command into a symmetrical bilateral activation in the brainstem. J Neurosci 2010; 30:523-33. [PMID: 20071515 PMCID: PMC6632989 DOI: 10.1523/jneurosci.3433-09.2010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 11/12/2009] [Accepted: 11/12/2009] [Indexed: 11/21/2022] Open
Abstract
A unilateral activation of the mesencephalic locomotor region (MLR) produces symmetrical bilateral locomotion in all vertebrate species tested to date. How this occurs remains unresolved. This study examined the possibility that the symmetry occurred at the level of the inputs from the MLR to reticulospinal (RS) cells. In lamprey semi-intact preparations, we recorded intracellular responses of pairs of large, homologous RS cells on both sides to stimulation of the MLR on one side. The synaptic responses on both sides were very similar in shape, amplitude, and threshold intensity. Increasing MLR stimulation intensity produced a symmetrical increase in the magnitude of the responses on both sides. Ca(2+) imaging confirmed the bilateral activation of smaller-sized RS cells as well. In a high-divalent cation solution, the synaptic responses of homologous RS cells persisted and exhibited a constant latency during high-frequency stimulation. Moreover, during gradual replacement of normal Ringer's solution with a Ca(2+)-free solution, the magnitude of responses showed a gradual reduction with a similar time course in the homologous RS cells. These results support the idea that the MLR projects monosynaptically to RS cells on both sides with symmetrical inputs. During locomotion of the semi-intact preparation, the discharge pattern was also very similar in homologous bilateral RS cells. Anatomical experiments confirmed the presence of MLR neurons projecting ipsilaterally to the reticular formation intermingled with neurons projecting contralaterally. We conclude that the bilaterally symmetrical MLR inputs to RS cells are likely contributors to generating symmetrical locomotor activity.
Collapse
Affiliation(s)
- Frédéric Brocard
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Dimitri Ryczko
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Karine Fénelon
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Raja Hatem
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Delphine Gonzales
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - François Auclair
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Réjean Dubuc
- Département de Kinanthropologie Université du Québec à Montréal, Montréal, Québec H3C 3P8, Canada, and
- Groupe de Recherche sur le Système Nerveux Central, Département de Physiologie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| |
Collapse
|
26
|
Whelan PJ. The involvement of the motor cortex in postural control: a delicate balancing act. J Physiol 2009; 587:3753. [PMID: 19648441 DOI: 10.1113/jphysiol.2009.176750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Patrick J Whelan
- Hotchkiss Brain Institute, Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
27
|
Blood AJ. New hypotheses about postural control support the notion that all dystonias are manifestations of excessive brain postural function. ACTA ACUST UNITED AC 2008; 1:14-25. [PMID: 19180244 DOI: 10.1016/j.bihy.2008.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This paper postulates that all forms of the neurological movement disorder, dystonia, can be argued to reflect excessive function of one or more components of the brain postural system. This is based on four central arguments. First, because some forms of postural control are already known to be dynamic, rather than static, it is suggested that hyperkinetic dystonias reflect excessive function of dynamic postures, rather than abnormal movements. Second, the range of functional roles served by the postural system is hypothesized to include direct control of movement, suggesting a postural basis for task-specific dystonias. Third, by defining posture as a neural system that maintains body stabilization, it can be shown that the range of mechanical means of implementing stabilization, including co-contraction of antagonistic muscles, matches the range of presentations of dystonia. Fourth, it is shown that the above premises are able to account for previously unexplained observations in dystonia. Based on the inhibitory influence that stabilizing mechanisms exert on movement, it is suggested that the broad functional role that is here referred to as posture may be the function served by the indirect pathway of the basal ganglia. Specifically, it is proposed that this pathway centrally coordinates function of the distributed network of brain regions controlling posture and, in conjunction with the direct pathway, coordinates posture and movement.
Collapse
Affiliation(s)
- Anne J Blood
- Departments of Psychiatry and Neurology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, CNY 149-2301, 13th St., Charlestown, MA 02129
| |
Collapse
|
28
|
Lockhart DB, Ting LH. Optimal sensorimotor transformations for balance. Nat Neurosci 2007; 10:1329-36. [PMID: 17873869 DOI: 10.1038/nn1986] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 08/24/2007] [Indexed: 02/05/2023]
Abstract
Here we have identified a sensorimotor transformation that is used by a mammalian nervous system to produce a multijoint motor behavior. Using a simple biomechanical model, a delayed-feedback rule based on an optimal tradeoff between postural error and neural effort explained patterns of muscle activation in response to a sudden loss of balance in cats. Following the loss of large sensory afferents, changes in these muscle-activation patterns reflected an optimal reweighting of sensory feedback gains to minimize postural instability. Specifically, a loss of center-of-mass-acceleration information, which allowed for a rapid initial rise in the muscle activity in intact animals, was absent after large-fiber sensory neuropathy. Our results demonstrate that a simple and flexible neural feedback control strategy coordinates multiple muscles over time via a small set of extrinsic, task-level variables during complex multijoint natural movements.
Collapse
Affiliation(s)
- Daniel B Lockhart
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 313 Ferst Drive, Atlanta, Georgia 30332-0535, USA
| | | |
Collapse
|