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Ryczko D. The Mesencephalic Locomotor Region: Multiple Cell Types, Multiple Behavioral Roles, and Multiple Implications for Disease. Neuroscientist 2024; 30:347-366. [PMID: 36575956 PMCID: PMC11107129 DOI: 10.1177/10738584221139136] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The mesencephalic locomotor region (MLR) controls locomotion in vertebrates. In humans with Parkinson disease, locomotor deficits are increasingly associated with decreased activity in the MLR. This brainstem region, commonly considered to include the cuneiform and pedunculopontine nuclei, has been explored as a target for deep brain stimulation to improve locomotor function, but the results are variable, from modest to promising. However, the MLR is a heterogeneous structure, and identification of the best cell type to target is only beginning. Here, I review the studies that uncovered the role of genetically defined MLR cell types, and I highlight the cells whose activation improves locomotor function in animal models of Parkinson disease. The promising cell types to activate comprise some glutamatergic neurons in the cuneiform and caudal pedunculopontine nuclei, as well as some cholinergic neurons of the pedunculopontine nucleus. Activation of MLR GABAergic neurons should be avoided, since they stop locomotion or evoke bouts flanked with numerous stops. MLR is also considered a potential target in spinal cord injury, supranuclear palsy, primary progressive freezing of gait, or stroke. Better targeting of the MLR cell types should be achieved through optimized deep brain stimulation protocols, pharmacotherapy, or the development of optogenetics for human use.
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Affiliation(s)
- Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada
- Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada
- Neurosciences Sherbrooke, Sherbrooke, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Canada
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Rejc E, Bowersock C, Pisolkar T, Omofuma I, Luna T, Khan M, Santamaria V, Ugiliweneza B, Angeli CA, Forrest GF, Stein J, Agrawal S, Harkema SJ. Robotic Postural Training With Epidural Stimulation for the Recovery of Upright Postural Control in Individuals With Motor Complete Spinal Cord Injury: A Pilot Study. Neurotrauma Rep 2024; 5:277-292. [PMID: 38515546 PMCID: PMC10956531 DOI: 10.1089/neur.2024.0013] [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] [Indexed: 03/23/2024] Open
Abstract
Activity-based training and lumbosacral spinal cord epidural stimulation (scES) have the potential to restore standing and walking with self-balance assistance after motor complete spinal cord injury (SCI). However, improvements in upright postural control have not previously been addressed in this population. Here, we implemented a novel robotic postural training with scES, performed with free hands, to restore upright postural control in individuals with chronic, cervical (n = 5) or high-thoracic (n = 1) motor complete SCI, who had previously undergone stand training with scES using a walker or a standing frame for self-balance assistance. Robotic postural training re-enabled and/or largely improved the participants' ability to control steady standing, self-initiated trunk movements and upper limb reaching movements while standing with free hands, receiving only external assistance for pelvic control. These improvements were associated with neuromuscular activation pattern adaptations above and below the lesion. These findings suggest that the human spinal cord below the level of injury can generate meaningful postural responses when its excitability is modulated by scES, and can learn to improve these responses. Upright postural control improvements can enhance functional motor recovery promoted by scES after severe SCI.
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Affiliation(s)
- Enrico Rejc
- Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA
- Department of Medicine, University of Udine, Udine, Italy
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Collin Bowersock
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, Arizona, USA
| | - Tanvi Pisolkar
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Isirame Omofuma
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Tatiana Luna
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Moiz Khan
- Department of Radiology at BWH, Harvard Medical School, Boston, Massachusetts, USA
| | - Victor Santamaria
- Department of Physical Therapy, New York Medical College, Valhalla, New York, USA
| | - Beatrice Ugiliweneza
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, USA
| | - Claudia A Angeli
- Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA
| | - Gail F Forrest
- Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Joel Stein
- Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, New York, USA
| | - Sunil Agrawal
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
- Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, New York, USA
| | - Susan J Harkema
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, USA
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Bowersock CD, Pisolkar T, Omofuma I, Luna T, Khan M, Santamaria V, Stein J, Agrawal S, Harkema SJ, Rejc E. Robotic upright stand trainer (RobUST) and postural control in individuals with spinal cord injury. J Spinal Cord Med 2023; 46:889-899. [PMID: 35532324 PMCID: PMC10653750 DOI: 10.1080/10790268.2022.2069532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
CONTEXT/OBJECTIVE Assessed feasibility and potential effectiveness of using a novel robotic upright stand trainer (RobUST) to deliver postural perturbations or provide assistance-as-needed at the trunk while individuals with spinal cord injury (SCI) performed stable standing and self-initiated trunk movements. These tasks were assessed with research participants' hands on handlebars for self-balance assistance (hands on) and with hands off (free hands). DESIGN Proof of concept study. PARTICIPANTS Four individuals with motor complete (n = 3) or incomplete (n = 1) SCI who were not able to achieve independent standing and presented a neurological lesion level ranging from cervical 4 to thoracic 2. OUTCOME MEASURES Ground reaction forces, trunk displacement, and electromyography activity of trunk and lower limb muscles. RESULTS Research participants received continuous pelvic assistance via RobUST, and manual trainer assistance at the knees to maintain standing. Participants were able to attempt all tasks. Free hands trunk perturbations resulted in greater load bearing-related sensory information (73% ipsilateral vertical loading), trunk displacement (57%), and muscle activation compared to hands on. Similarly, free hands stable standing with RobUST assistance-as-needed resulted in 8.5% larger bodyweight bearing, 112% larger trunk movement velocity, and higher trunk muscles activation compared to standing with hands on. Self-initiated trunk movements controlled by hands on showed 116% greater trunk displacement, 10% greater vertical ground reaction force, and greater ankle muscle activation compared to free hands. CONCLUSION RobUST established a safe and challenging standing environment for individuals with SCI and has the potential to improve training paradigms and assessments of standing postural control.
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Affiliation(s)
- Collin D. Bowersock
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Tanvi Pisolkar
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Isirame Omofuma
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Tatiana Luna
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Moiz Khan
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Victor Santamaria
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Joel Stein
- Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, New York, USA
| | - Sunil Agrawal
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
- Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, New York, USA
| | - Susan J. Harkema
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, USA
- Frazier Rehabilitation Institute, University of Louisville Health, Louisville, Kentucky, USA
- Department of Bioengineering, University of Louisville, Louisville, Kentucky, USA
| | - Enrico Rejc
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, USA
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Kalinina DS, Lyakhovetskii VA, Gorskii OV, Shkorbatova PY, Pavlova NV, Bazhenova EY, Sysoev YI, Gainetdinov RR, Musienko PE. Alteration of Postural Reactions in Rats with Different Levels of Dopamine Depletion. Biomedicines 2023; 11:1958. [PMID: 37509596 PMCID: PMC10377029 DOI: 10.3390/biomedicines11071958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/19/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
Dopamine (DA) is the critical neurotransmitter involved in the unconscious control of muscle tone and body posture. We evaluated the general motor capacities and muscle responses to postural disturbance in three conditions: normal DA level (wild-type rats, WT), mild DA deficiency (WT after administration of α-methyl-p-tyrosine-AMPT, that blocks DA synthesis), and severe DA depletion (DAT-KO rats after AMPT). The horizontal displacements in WT rats elicited a multi-component EMG corrective response in the flexor and extensor muscles. Similar to the gradual progression of DA-related diseases, we observed different degrees of bradykinesia, rigidity, and postural instability after AMPT. The mild DA deficiency impaired the initiation pattern of corrective responses, specifically delaying the extensor muscles' activity ipsilaterally to displacement direction and earlier extensor activity from the opposite side. DA depletion in DAT-KO rats after AMPT elicited tremors, general stiffness, and akinesia, and caused earlier response to horizontal displacements in the coactivated flexor and extensor muscles bilaterally. The data obtained show the specific role of DA in postural reactions and suggest that this experimental approach can be used to investigate sensorimotor control in different dopamine-deficient states and to model DA-related diseases.
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Affiliation(s)
- Daria S Kalinina
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223 St. Petersburg, Russia
- Department of Neuroscience, Sirius University of Science and Technology, 354340 Sirius, Russia
| | | | - Oleg V Gorskii
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034 St. Petersburg, Russia
- Center for Biomedical Engineering, National University of Science and Technology "MISIS", 119049 Moscow, Russia
| | - Polina Yu Shkorbatova
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Department of Neuroscience, Sirius University of Science and Technology, 354340 Sirius, Russia
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Natalia V Pavlova
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Elena Yu Bazhenova
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Yurii I Sysoev
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Department of Neuroscience, Sirius University of Science and Technology, 354340 Sirius, Russia
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034 St. Petersburg, Russia
- Department of Pharmacology and Clinical Pharmacology, Saint Petersburg State Chemical and Pharmaceutical University, 197022 St. Petersburg, Russia
| | - Raul R Gainetdinov
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Pavel E Musienko
- Institute of Translational Biomedicine, St. Petersburg State University Hospital, St. Petersburg State University, 199034 St. Petersburg, Russia
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034 St. Petersburg, Russia
- Life Improvement by Future Technologies Center "LIFT", 143025 Moscow, Russia
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Lacroix-Ouellette P, Dubuc R. Brainstem neural mechanisms controlling locomotion with special reference to basal vertebrates. Front Neural Circuits 2023; 17:910207. [PMID: 37063386 PMCID: PMC10098025 DOI: 10.3389/fncir.2023.910207] [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: 04/01/2022] [Accepted: 03/13/2023] [Indexed: 04/03/2023] Open
Abstract
Over the last 60 years, the basic neural circuitry responsible for the supraspinal control of locomotion has progressively been uncovered. Initially, significant progress was made in identifying the different supraspinal structures controlling locomotion in mammals as well as some of the underlying mechanisms. It became clear, however, that the complexity of the mammalian central nervous system (CNS) prevented researchers from characterizing the detailed cellular mechanisms involved and that animal models with a simpler nervous system were needed. Basal vertebrate species such as lampreys, xenopus embryos, and zebrafish became models of choice. More recently, optogenetic approaches have considerably revived interest in mammalian models. The mesencephalic locomotor region (MLR) is an important brainstem region known to control locomotion in all vertebrate species examined to date. It controls locomotion through intermediary cells in the hindbrain, the reticulospinal neurons (RSNs). The MLR comprises populations of cholinergic and glutamatergic neurons and their specific contribution to the control of locomotion is not fully resolved yet. Moreover, the downward projections from the MLR to RSNs is still not fully understood. Reporting on discoveries made in different animal models, this review article focuses on the MLR, its projections to RSNs, and the contribution of these neural elements to the control of locomotion. Excellent and detailed reviews on the brainstem control of locomotion have been recently published with emphasis on mammalian species. The present review article focuses on findings made in basal vertebrates such as the lamprey, to help direct new research in mammals, including humans.
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Affiliation(s)
| | - Réjean Dubuc
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
- Department of Physical Activity Sciences, Université du Québec à Montréal, Montréal, QC, Canada
- Research Group for Adapted Physical Activity, Université du Québec à Montréal, Montréal, QC, Canada
- *Correspondence: Réjean Dubuc,
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Feasibility and Validity of Postural Reaction Tests in the Neurological Examination in Healthy Rabbits. Vet Sci 2023; 10:vetsci10030176. [PMID: 36977215 PMCID: PMC10051650 DOI: 10.3390/vetsci10030176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 02/08/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Neurological examination remains a fundamental step in the care of patients with neurological disorders. However, studies evaluating the feasibility and validity of neurological examination in rabbits are limited. In this study, postural reaction tests or methods commonly performed in dogs and cats were evaluated in clinically healthy rabbits, and we aimed to postulate a simplified examination list according to the results. The feasibility and validity of each test were determined and screened using a cut-off value of 90%. For the remaining tests/methods, the response rates of tests with similar neuroanatomical pathways were compared. Among the 34 healthy rabbits tested, one method of the hopping reaction (holding then lowering the rabbit quickly towards the floor with only the tested limb touching the ground), the hemi-walking test, the wheelbarrowing test, and the righting response yielded a feasibility and validity of over 90%. When comparing tests/methods with similar neuroanatomical pathways, the normal response rate of the hopping reaction was comparable to that of the hemi-walking test. We conclude that in healthy rabbits, hopping reaction tests using the method mentioned above, hemi-walking, wheelbarrowing, and righting responses are likely to be feasible postural reaction tests that yield consistent and normal responses.
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Zelenin PV, Lyalka VF, Deliagina TG. Changes in operation of postural networks in rabbits with postural functions recovered after lateral hemisection of the spinal cord. J Physiol 2023; 601:307-334. [PMID: 36463517 PMCID: PMC9840688 DOI: 10.1113/jp283458] [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: 08/19/2022] [Accepted: 11/30/2022] [Indexed: 12/07/2022] Open
Abstract
Acute lateral hemisection of the spinal cord (LHS) severely impairs postural functions, which recover over time. Here, to reveal changes in the operation of postural networks underlying the recovery, male rabbits with recovered postural functions after LHS at T12 (R-rabbits) were used. After decerebration, we characterized the responses of individual spinal interneurons from L5 along with hindlimb EMG responses to stimulation causing postural limb reflexes (PLRs) that substantially contribute to postural corrections in intact animals. The data were compared with those obtained in our previous studies of rabbits with the intact spinal cord and rabbits after acute LHS. Although, in R-rabbits, the EMG responses to postural disturbances both ipsilateral and contralateral to the LHS (ipsi-LHS and co-LHS) were only slightly distorted, PLRs on the co-LHS side (unaffected by acute LHS) were distorted substantially and PLRs on the ipsi-LHS side (abolished by acute LHS) were close to control. Thus, in R-rabbits, plastic changes develop in postural networks both affected and unaffected by acute LHS. PLRs on the ipsi-LHS side recover mainly as a result of changes at brainstem-cerebellum-spinal levels, whereas the forebrain is substantially involved in the generation of PLRs on the co-LHS side. We found that, in areas of grey matter in which the activity of spinal neurons of the postural network was significantly decreased after acute LHS, it recovered to the control level, whereas, in areas unaffected by acute LHS, it was significantly changed. These changes underlie the recovery and distortion of PLRs on the ipsi-LHS and co-LHS sides, respectively. KEY POINTS: After lateral hemisection of the spinal cord (LHS), postural functions recover over time. The underlying changes in the operation of postural networks are unknown. We compared the responses of individual spinal neurons and hindlimb muscles to stimulation causing postural limb reflexes (PLRs) in recovered LHS-rabbits with those obtained in rabbits with the intact spinal cord and rabbits after acute LHS. We demonstrated that changes underlying the recovery of postural functions take place not only in postural networks that are severely impaired, but also in those that are almost unaffected by acute LHS. PLRs on the LHS side recover mainly as a result of changes at brainstem-cerebellum-spinal levels, whereas the forebrain is substantially involved in the generation of PLRs contralateral to the LHS.
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Affiliation(s)
- Pavel V. Zelenin
- Department of Neuroscience Karolinska Institute Stockholm Sweden
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8
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Tarbert DK, Murthy VD, Guzman DSM. Neurological examination in healthy adult inland bearded dragons (Pogona vitticeps). J Am Vet Med Assoc 2022; 260:1013-1023. [PMID: 35417409 DOI: 10.2460/javma.20.12.0706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate neurological tests and expected results in inland bearded dragons (Pogona vitticeps) and generate recommendations for bearded dragon-specific neurological examination. ANIMALS 26 healthy adult inland bearded dragons. PROCEDURES A complete neurological examination utilizing tests described in both mammals and reptiles was performed on each lizard, and test feasibility and outcome were recorded. RESULTS Tests with poor feasibility included oculocardiac reflex (successfully completed in 62% [16/26] of animals) and voluntary ambulation and swallowing by use of a food item (0% [0/26] of animals). Tests with outcomes considered abnormal in mammals but attributable to normal bearded dragon behavior included head position (head tilt present in 12% [3/26]) and head movement (head bob present in 4% [1/26]). Many tests had absent or inconsistent outcomes, including menace response (present in 19% [5/26]), proprioceptive positioning (present in 4% [1/26] in the thoracic limbs and 0% [0/26] in the pelvic limbs), vent reflex (present in 27% [7/26]), and myotatic reflexes (biceps present in 8% [2/26]; patellar, gastrocnemius, and triceps present in 0% [0/26]). Extensor postural thrust was absent in all successfully tested animals, but a novel reflex termed the caudal thoracic extensor reflex was noted instead in all observed animals (100% [21/21]). CLINICAL RELEVANCE Tests with poor feasibility or inconsistent outcomes should have low priority or be excluded from neurological examinations of inland bearded dragons. Normal behaviors should be considered for head position and movement. A bearded dragon-specific neurological examination protocol derived from these findings is described and recommended in order to decrease stress and improve neurolocalization.
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Affiliation(s)
- Danielle K Tarbert
- 1William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA
| | - Vishal D Murthy
- 1William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA
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9
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Dougherty JB, Disse GD, Bridges NR, Moxon KA. Effect of spinal cord injury on neural encoding of spontaneous postural perturbations in the hindlimb sensorimotor cortex. J Neurophysiol 2021; 126:1555-1567. [PMID: 34379540 PMCID: PMC8782649 DOI: 10.1152/jn.00727.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 11/22/2022] Open
Abstract
Supraspinal signals play a significant role in compensatory responses to postural perturbations. Although the cortex is not necessary for basic postural tasks in intact animals, its role in responding to unexpected postural perturbations after spinal cord injury (SCI) has not been studied. To better understand how SCI impacts cortical encoding of postural perturbations, the activity of single neurons in the hindlimb sensorimotor cortex (HLSMC) was recorded in the rat during unexpected tilts before and after a complete midthoracic spinal transection. In a subset of animals, limb ground reaction forces were also collected. HLSMC activity was strongly modulated in response to different tilt profiles. As the velocity of the tilt increased, more information was conveyed by the HLSMC neurons about the perturbation due to increases in both the number of recruited neurons and the magnitude of their responses. SCI led to attenuated and delayed hindlimb ground reaction forces. However, HLSMC neurons remained responsive to tilts after injury but with increased latencies and decreased tuning to slower tilts. Information conveyed by cortical neurons about the tilts was therefore reduced after SCI, requiring more cells to convey the same amount of information as before the transection. Given that reorganization of the hindlimb sensorimotor cortex in response to therapy after complete midthoracic SCI is necessary for behavioral recovery, this sustained encoding of information after SCI could be a substrate for the reorganization that uses sensory information from above the lesion to control trunk muscles that permit weight-supported stepping and postural control.NEW & NOTEWORTHY The role of cortical circuits in the encoding of posture and balance is of interest for developing therapies for spinal cord injury. This work demonstrated that unexpected postural perturbations are encoded in the hindlimb sensorimotor cortex even in the absence of hindlimb sensory feedback. In fact, the hindlimb sensorimotor cortex continues to encode for postural perturbations after complete spinal transection.
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Affiliation(s)
- Jaimie B Dougherty
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania
| | - Gregory D Disse
- Department of Biomedical Engineering, University of California at Davis, Davis, California
| | - Nathaniel R Bridges
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio
| | - Karen A Moxon
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania
- Department of Biomedical Engineering, University of California at Davis, Davis, California
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10
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Martynyuk AE, Ju LS, Morey TE. The potential role of stress and sex steroids in heritable effects of sevoflurane. Biol Reprod 2021; 105:735-746. [PMID: 34192761 DOI: 10.1093/biolre/ioab129] [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] [Received: 03/01/2021] [Revised: 03/17/2021] [Accepted: 06/25/2021] [Indexed: 12/11/2022] Open
Abstract
Most surgical procedures require general anesthesia, which is a reversible deep sedation state lacking all perception. The induction of this state is possible because of complex molecular and neuronal network actions of general anesthetics (GAs) and other pharmacological agents. Laboratory and clinical studies indicate that the effects of GAs may not be completely reversible upon anesthesia withdrawal. The long-term neurocognitive effects of GAs, especially when administered at the extremes of ages, are an increasingly recognized health concern and the subject of extensive laboratory and clinical research. Initial studies in rodents suggest that the adverse effects of GAs, whose actions involve enhancement of GABA type A receptor activity (GABAergic GAs), can also extend to future unexposed offspring. Importantly, experimental findings show that GABAergic GAs may induce heritable effects when administered from the early postnatal period to at least young adulthood, covering nearly all age groups that may have children after exposure to anesthesia. More studies are needed to understand when and how the clinical use of GAs in a large and growing population of patients can result in lower resilience to diseases in the even larger population of their unexposed offspring. This minireview is focused on the authors' published results and data in the literature supporting the notion that GABAergic GAs, in particular sevoflurane, may upregulate systemic levels of stress and sex steroids and alter expressions of genes that are essential for the functioning of these steroid systems. The authors hypothesize that stress and sex steroids are involved in the mediation of sex-specific heritable effects of sevoflurane.
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Affiliation(s)
- Anatoly E Martynyuk
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA.,McKnight Brain Institute, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ling-Sha Ju
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Timothy E Morey
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA
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11
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Chang SJ, Cajigas I, Guest JD, Noga BR, Widerström-Noga E, Haq I, Fisher L, Luca CC, Jagid JR. Deep brain stimulation of the Cuneiform nucleus for levodopa-resistant freezing of gait in Parkinson's disease: study protocol for a prospective, pilot trial. Pilot Feasibility Stud 2021; 7:117. [PMID: 34078477 PMCID: PMC8169408 DOI: 10.1186/s40814-021-00855-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 05/21/2021] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Freezing of gait (FOG) is a particularly debilitating motor deficit seen in a subset of Parkinson's disease (PD) patients that is poorly responsive to standard levodopa therapy or deep brain stimulation (DBS) of established PD targets such as the subthalamic nucleus and the globus pallidus interna. The proposal of a DBS target in the midbrain, known as the pedunculopontine nucleus (PPN) to address FOG, was based on its observed pathology in PD and its hypothesized involvement in locomotor control as a part of the mesencephalic locomotor region, a functionally defined area of the midbrain that elicits locomotion in both intact animals and decerebrate animal preparations with electrical stimulation. Initial reports of PPN DBS were met with much enthusiasm; however, subsequent studies produced mixed results, and recent meta-analysis results have been far less convincing than initially expected. A closer review of the extensive mesencephalic locomotor region (MLR) preclinical literature, including recent optogenetics studies, strongly suggests that the closely related cuneiform nucleus (CnF), just dorsal to the PPN, may be a superior target to promote gait initiation. METHODS We will conduct a prospective, open-label, single-arm pilot study to assess safety and feasibility of CnF DBS in PD patients with levodopa-refractory FOG. Four patients will receive CnF DBS and have gait assessments with and without DBS during a 6-month follow-up. DISCUSSION This paper presents the study design and rationale for a pilot study investigating a novel DBS target for gait dysfunction, including targeting considerations. This pilot study is intended to support future larger scale clinical trials investigating this target. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT04218526 (registered January 6, 2020).
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Affiliation(s)
- Stephano J Chang
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurosurgery, University of British Columbia, Vancouver, BC, Canada
| | - Iahn Cajigas
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 N.W. 14th Terrace, Miami, FL, 33136, USA
| | - James D Guest
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 N.W. 14th Terrace, Miami, FL, 33136, USA
| | - Brian R Noga
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 N.W. 14th Terrace, Miami, FL, 33136, USA
| | - Eva Widerström-Noga
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 N.W. 14th Terrace, Miami, FL, 33136, USA
| | - Ihtsham Haq
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Letitia Fisher
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 N.W. 14th Terrace, Miami, FL, 33136, USA
| | - Corneliu C Luca
- The Miami Project to Cure Paralysis, Miami, FL, USA.,Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jonathan R Jagid
- The Miami Project to Cure Paralysis, Miami, FL, USA. .,Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 N.W. 14th Terrace, Miami, FL, 33136, USA.
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12
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Differential Contribution of V0 Interneurons to Execution of Rhythmic and Nonrhythmic Motor Behaviors. J Neurosci 2021; 41:3432-3445. [PMID: 33637562 DOI: 10.1523/jneurosci.1979-20.2021] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 11/21/2022] Open
Abstract
Locomotion, scratching, and stabilization of the body orientation in space are basic motor functions which are critically important for animal survival. Their execution requires coordinated activity of muscles located in the left and right halves of the body. Commissural interneurons (CINs) are critical elements of the neuronal networks underlying the left-right motor coordination. V0 interneurons (characterized by the early expression of the transcription factor Dbx1) contain a major class of CINs in the spinal cord (excitatory, V0V; inhibitory, V0D), and a small subpopulation of excitatory ipsilaterally projecting interneurons. The role of V0 CINs in left-right coordination during forward locomotion was demonstrated earlier. Here, to reveal the role of glutamatergic V0 and other V0 subpopulations in control of backward locomotion, scratching, righting behavior, and postural corrections, kinematics of these movements performed by wild-type mice and knock-out mice with glutamatergic V0 or all V0 interneurons ablated were compared. Our results suggest that the functional effect of excitatory V0 neurons during backward locomotion and scratching is inhibitory, and that the execution of scratching involves active inhibition of the contralateral scratching central pattern generator mediated by excitatory V0 neurons. By contrast, other V0 subpopulations are elements of spinal networks generating postural corrections. Finally, all V0 subpopulations contribute to the generation of righting behavior. We found that different V0 subpopulations determine left-right coordination in the anterior and posterior parts of the body during a particular behavior. Our study shows a differential contribution of V0 subpopulations to diverse motor acts that provides new insight to organization of motor circuits.SIGNIFICANCE STATEMENT Commissural interneurons with their axons crossing the midline of the nervous system are critical elements of the neuronal networks underlying the left-right motor coordination. For the majority of motor behaviors, the neuronal mechanisms underlying left-right coordination are unknown. Here, we demonstrate the functional role of excitatory V0 neurons and other subpopulations of V0 interneurons in control of a number of basic motor behaviors-backward locomotion, scratching, righting behavior, and postural corrections-which are critically important for animal survival. We have shown that different subpopulations of V0 neurons determine left-right coordination in the context of different behaviors as well as in the anterior and posterior parts of the body during a particular behavior.
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13
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Chen M, Ouyang W, Xia Y, Zeng Y, Wang S, Duan K, Fang C. Association between well‐characterized gene polymorphisms and the hypnosis response caused by sevoflurane‐induced anaesthesia. J Clin Pharm Ther 2020; 45:1442-1451. [PMID: 33016519 DOI: 10.1111/jcpt.13275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/28/2020] [Accepted: 09/07/2020] [Indexed: 01/01/2023]
Affiliation(s)
- Ming‐Hua Chen
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
- Hunan Key Laboratory of Brain Homeostasis Third Xiangya Hospital Central South University Changsha China
| | - Wen Ouyang
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
- Hunan Key Laboratory of Brain Homeostasis Third Xiangya Hospital Central South University Changsha China
| | - Yu‐Hao Xia
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
| | - You‐Jie Zeng
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
| | - Sai‐Ying Wang
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
| | - Kai‐Ming Duan
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
| | - Chao Fang
- Department of Anesthesiology Third Xiangya Hospital Central South University Changsha China
- Hunan Key Laboratory of Brain Homeostasis Third Xiangya Hospital Central South University Changsha China
- Postdoctoral Research Workstation of Clinical Medicine Third Xiangya Hospital Central South University Changsha China
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14
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Latash EM, Barnett WH, Park H, Rider JM, Klishko AN, Prilutsky BI, Molkov YI. Frontal plane dynamics of the centre of mass during quadrupedal locomotion on a split-belt treadmill. J R Soc Interface 2020; 17:20200547. [PMID: 32900302 PMCID: PMC7536050 DOI: 10.1098/rsif.2020.0547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/14/2020] [Indexed: 01/08/2023] Open
Abstract
Our previous study of cat locomotion demonstrated that lateral displacements of the centre of mass (COM) were strikingly similar to those of human walking and resembled the behaviour of an inverted pendulum (Park et al. 2019 J. Exp. Biol.222, 14. (doi:10.1242/jeb.198648)). Here, we tested the hypothesis that frontal plane dynamics of quadrupedal locomotion are consistent with an inverted pendulum model. We developed a simple mathematical model of balance control in the frontal plane based on an inverted pendulum and compared model behaviour with that of four cats locomoting on a split-belt treadmill. The model accurately reproduced the lateral oscillations of cats' COM vertical projection. We inferred the effects of experimental perturbations on the limits of dynamic stability using data from different split-belt speed ratios with and without ipsilateral paw anaesthesia. We found that the effect of paw anaesthesia could be explained by the induced bias in the perceived position of the COM, and the magnitude of this bias depends on the belt speed difference. Altogether, our findings suggest that the balance control system is actively involved in cat locomotion to provide dynamic stability in the frontal plane, and that paw cutaneous receptors contribute to the representation of the COM position in the nervous system.
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Affiliation(s)
- E. M. Latash
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA, USA
| | - W. H. Barnett
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA, USA
| | - H. Park
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA
| | - J. M. Rider
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA, USA
| | - A. N. Klishko
- School of Biological Sciences, Georgia Institute of Technology, 555 14th street NW, Atlanta 30332, GA, USA
| | - B. I. Prilutsky
- School of Biological Sciences, Georgia Institute of Technology, 555 14th street NW, Atlanta 30332, GA, USA
| | - Y. I. Molkov
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
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15
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Zelenin PV, Lyalka VF, Orlovsky GN, Deliagina TG. Changes in Activity of Spinal Postural Networks at Different Time Points After Spinalization. Front Cell Neurosci 2019; 13:387. [PMID: 31496938 PMCID: PMC6712497 DOI: 10.3389/fncel.2019.00387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/06/2019] [Indexed: 11/25/2022] Open
Abstract
Postural limb reflexes (PLRs) are an essential component of postural corrections. Spinalization leads to disappearance of postural functions (including PLRs). After spinalization, spastic, incorrectly phased motor responses to postural perturbations containing oscillatory EMG bursting gradually develop, suggesting plastic changes in the spinal postural networks. Here, to reveal these plastic changes, rabbits at 3, 7, and 30 days after spinalization at T12 were decerebrated, and responses of spinal interneurons from L5 along with hindlimb muscles EMG responses to postural sensory stimuli, causing PLRs in subjects with intact spinal cord (control), were characterized. Like in control and after acute spinalization, at each of three studied time points after spinalization, neurons responding to postural sensory stimuli were found. Proportion of such neurons during 1st month after spinalization did not reach the control level, and was similar to that observed after acute spinalization. In contrast, their activity (which was significantly decreased after acute spinalization) reached the control value at 3 days after spinalization and remained close to this level during the following month. However, the processing of postural sensory signals, which was severely distorted after acute spinalization, did not recover by 30 days after injury. In addition, we found a significant enhancement of the oscillatory activity in a proportion of the examined neurons, which could contribute to generation of oscillatory EMG bursting. Motor responses to postural stimuli (which were almost absent after acute spinalization) re-appeared at 3 days after spinalization, although they were very weak, irregular, and a half of them was incorrectly phased in relation to postural stimuli. Proportion of correct and incorrect motor responses remained almost the same during the following month, but their amplitude gradually increased. Thus, spinalization triggers two processes of plastic changes in the spinal postural networks: rapid (taking days) restoration of normal activity level in spinal interneurons, and slow (taking months) recovery of motoneuronal excitability. Most likely, recovery of interneuronal activity underlies re-appearance of motor responses to postural stimuli. However, absence of recovery of normal processing of postural sensory signals and enhancement of oscillatory activity of neurons result in abnormal PLRs and loss of postural functions.
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16
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Daghfous G, Auclair F, Clotten F, Létourneau JL, Atallah E, Millette JP, Derjean D, Robitaille R, Zielinski BS, Dubuc R. GABAergic modulation of olfactomotor transmission in lampreys. PLoS Biol 2018; 16:e2005512. [PMID: 30286079 PMCID: PMC6191151 DOI: 10.1371/journal.pbio.2005512] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 10/16/2018] [Accepted: 09/18/2018] [Indexed: 12/21/2022] Open
Abstract
Odor-guided behaviors, including homing, predator avoidance, or food and mate searching, are ubiquitous in animals. It is only recently that the neural substrate underlying olfactomotor behaviors in vertebrates was uncovered in lampreys. It consists of a neural pathway extending from the medial part of the olfactory bulb (medOB) to locomotor control centers in the brainstem via a single relay in the caudal diencephalon. This hardwired olfactomotor pathway is present throughout life and may be responsible for the olfactory-induced motor behaviors seen at all life stages. We investigated modulatory mechanisms acting on this pathway by conducting anatomical (tract tracing and immunohistochemistry) and physiological (intracellular recordings and calcium imaging) experiments on lamprey brain preparations. We show that the GABAergic circuitry of the olfactory bulb (OB) acts as a gatekeeper of this hardwired sensorimotor pathway. We also demonstrate the presence of a novel olfactomotor pathway that originates in the non-medOB and consists of a projection to the lateral pallium (LPal) that, in turn, projects to the caudal diencephalon and to the mesencephalic locomotor region (MLR). Our results indicate that olfactory inputs can induce behavioral responses by activating brain locomotor centers via two distinct pathways that are strongly modulated by GABA in the OB. The existence of segregated olfactory subsystems in lampreys suggests that the organization of the olfactory system in functional clusters may be a common ancestral trait of vertebrates.
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Affiliation(s)
- Gheylen Daghfous
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
| | - François Auclair
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Felix Clotten
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Jean-Luc Létourneau
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Elias Atallah
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Jean-Patrick Millette
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Dominique Derjean
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Richard Robitaille
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Barbara S. Zielinski
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada
| | - Réjean Dubuc
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
- * E-mail:
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17
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Nigral Glutamatergic Neurons Control the Speed of Locomotion. J Neurosci 2017; 37:9759-9770. [PMID: 28924005 DOI: 10.1523/jneurosci.1810-17.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/08/2017] [Accepted: 08/26/2017] [Indexed: 01/16/2023] Open
Abstract
The mesencephalic locomotor region (MLR) plays a crucial role in locomotor control. In vertebrates, stimulation of the MLR at increasing intensities elicits locomotion of growing speed. This effect has been presumed to result from higher brain inputs activating the MLR like a dimmer switch. Here, we show in lampreys (Petromyzon marinus) of either sex that incremental stimulation of a region homologous to the mammalian substantia nigra pars compacta (SNc) evokes increasing activation of MLR cells with a graded increase in the frequency of locomotor movements. Neurons co-storing glutamate and dopamine were found to project from the primal SNc to the MLR. Blockade of glutamatergic transmission largely diminished MLR cell responses and locomotion. Local blockade of D1 receptors in the MLR decreased locomotor frequency, but did not disrupt the SNc-evoked graded control of locomotion. Our findings revealed the presence of a glutamatergic input to the MLR originating from the primal SNc that evokes graded locomotor movements.SIGNIFICANCE STATEMENT The mesencephalic locomotor region (MLR) plays a crucial role in the control of locomotion. It projects downward to reticulospinal neurons that in turn activate the spinal locomotor networks. Increasing the intensity of MLR stimulation produces a growing activation of reticulospinal cells and a progressive increase in the speed of locomotor movements. Since the discovery of the MLR some 50 years ago, it has been presumed that higher brain regions activate the MLR in a graded fashion, but this has not been confirmed yet. Here, using a combination of techniques from cell to behavior, we provide evidence of a new glutamatergic pathway activating the MLR in a graded fashion, and consequently evoking a progressive increase in locomotor output.
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18
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Ryczko D, Dubuc R. Dopamine and the Brainstem Locomotor Networks: From Lamprey to Human. Front Neurosci 2017; 11:295. [PMID: 28603482 PMCID: PMC5445171 DOI: 10.3389/fnins.2017.00295] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/11/2017] [Indexed: 11/13/2022] Open
Abstract
In vertebrates, dopamine neurons are classically known to modulate locomotion via their ascending projections to the basal ganglia that project to brainstem locomotor networks. An increased dopaminergic tone is associated with increase in locomotor activity. In pathological conditions where dopamine cells are lost, such as in Parkinson's disease, locomotor deficits are traditionally associated with the reduced ascending dopaminergic input to the basal ganglia. However, a descending dopaminergic pathway originating from the substantia nigra pars compacta was recently discovered. It innervates the mesencephalic locomotor region (MLR) from basal vertebrates to mammals. This pathway was shown to increase locomotor output in lampreys, and could very well play an important role in mammals. Here, we provide a detailed account on the newly found dopaminergic pathway in lamprey, salamander, rat, monkey, and human. In lampreys and salamanders, dopamine release in the MLR is associated with the activation of reticulospinal neurons that carry the locomotor command to the spinal cord. Dopamine release in the MLR potentiates locomotor movements through a D1-receptor mechanism in lampreys. In rats, stimulation of the substantia nigra pars compacta elicited dopamine release in the pedunculopontine nucleus, a known part of the MLR. In a monkey model of Parkinson's disease, a reduced dopaminergic innervation of the brainstem locomotor networks was reported. Dopaminergic fibers are also present in human pedunculopontine nucleus. We discuss the conserved locomotor role of this pathway from lamprey to mammals, and the hypothesis that this pathway could play a role in the locomotor deficits reported in Parkinson's disease.
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Affiliation(s)
- Dimitri Ryczko
- Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de MontréalMontréal, QC, Canada
| | - Réjean Dubuc
- Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de MontréalMontréal, QC, Canada.,Groupe de Recherche en Activité Physique Adaptée, Département des Sciences de l'Activité Physique, Université du Québec à MontréalMontréal, QC, Canada
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19
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Hsu LJ, Zelenin PV, Lyalka VF, Vemula MG, Orlovsky GN, Deliagina TG. Neural mechanisms of single corrective steps evoked in the standing rabbit. Neuroscience 2017; 347:85-102. [PMID: 28215990 PMCID: PMC5374252 DOI: 10.1016/j.neuroscience.2017.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/25/2017] [Accepted: 02/05/2017] [Indexed: 10/20/2022]
Abstract
Single steps in different directions are often used for postural corrections. However, our knowledge about the neural mechanisms underlying their generation is scarce. This study was aimed to characterize the corrective steps generated in response to disturbances of the basic body configuration caused by forward, backward or outward displacement of the hindlimb, as well as to reveal location in the CNS of the corrective step generating mechanisms. Video recording of the motor response to translation of the supporting surface under the hindlimb along with contact forces and activity of back and limb muscles was performed in freely standing intact and in fixed postmammillary rabbits. In intact rabbits, displacement of the hindlimb in any direction caused a lateral trunk movement toward the contralateral hindlimb, and then a corrective step in the direction opposite to the initial displacement. The time difference between onsets of these two events varied considerably. The EMG pattern in the supporting hindlimb was similar for all directions of corrective steps. It caused the increase in the limb stiffness. EMG pattern in the stepping limb differed in steps with different directions. In postmammillary rabbits the corrective stepping movements, as well as EMG patterns in both stepping and standing hindlimbs were similar to those observed in intact rabbits. This study demonstrates that the corrective trunk and limb movements are generated by separate mechanisms activated by sensory signals from the deviated limb. The neuronal networks generating postural corrective steps reside in the brainstem, cerebellum, and spinal cord.
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Affiliation(s)
- L-J Hsu
- Department of Neuroscience, Karolinska Institute, Stockholm SE-17177, Sweden
| | - P V Zelenin
- Department of Neuroscience, Karolinska Institute, Stockholm SE-17177, Sweden
| | - V F Lyalka
- Department of Neuroscience, Karolinska Institute, Stockholm SE-17177, Sweden
| | - M G Vemula
- Department of Neuroscience, Karolinska Institute, Stockholm SE-17177, Sweden
| | - G N Orlovsky
- Department of Neuroscience, Karolinska Institute, Stockholm SE-17177, Sweden
| | - T G Deliagina
- Department of Neuroscience, Karolinska Institute, Stockholm SE-17177, Sweden.
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20
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Zelenin PV, Lyalka VF, Orlovsky GN, Deliagina TG. Effect of acute lateral hemisection of the spinal cord on spinal neurons of postural networks. Neuroscience 2016; 339:235-253. [PMID: 27702647 PMCID: PMC5118056 DOI: 10.1016/j.neuroscience.2016.09.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/10/2016] [Accepted: 09/25/2016] [Indexed: 01/24/2023]
Abstract
In quadrupeds, acute lateral hemisection of the spinal cord (LHS) severely impairs postural functions, which recover over time. Postural limb reflexes (PLRs) represent a substantial component of postural corrections in intact animals. The aim of the present study was to characterize the effects of acute LHS on two populations of spinal neurons (F and E) mediating PLRs. For this purpose, in decerebrate rabbits, responses of individual neurons from L5 to stimulation causing PLRs were recorded before and during reversible LHS (caused by temporal cold block of signal transmission in lateral spinal pathways at L1), as well as after acute surgical LHS at L1. Results obtained after Sur-LHS were compared to control data obtained in our previous study. We found that acute LHS caused disappearance of PLRs on the affected side. It also changed a proportion of different types of neurons on that side. A significant decrease and increase in the proportion of F- and non-modulated neurons, respectively, was found. LHS caused a significant decrease in most parameters of activity in F-neurons located in the ventral horn on the lesioned side and in E-neurons of the dorsal horn on both sides. These changes were caused by a significant decrease in the efficacy of posture-related sensory input from the ipsilateral limb to F-neurons, and from the contralateral limb to both F- and E-neurons. These distortions in operation of postural networks underlie the impairment of postural control after acute LHS, and represent a starting point for the subsequent recovery of postural functions.
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Affiliation(s)
- P V Zelenin
- Department of Neuroscience, Karolinska Institute, SE-17177 Stockholm, Sweden
| | - V F Lyalka
- Department of Neuroscience, Karolinska Institute, SE-17177 Stockholm, Sweden
| | - G N Orlovsky
- Department of Neuroscience, Karolinska Institute, SE-17177 Stockholm, Sweden
| | - T G Deliagina
- Department of Neuroscience, Karolinska Institute, SE-17177 Stockholm, Sweden.
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21
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Koyama Y, Andoh T, Kamiya Y, Miyazaki T, Maruyama K, Kariya T, Goto T. Bumetanide, an Inhibitor of NKCC1 (Na-K-2Cl Cotransporter Isoform 1), Enhances Propofol-Induced Loss of Righting Reflex but Not Its Immobilizing Actions in Neonatal Rats. PLoS One 2016; 11:e0164125. [PMID: 27783647 PMCID: PMC5081196 DOI: 10.1371/journal.pone.0164125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 09/20/2016] [Indexed: 01/15/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) has been shown to induce excitation on immature neurons due to increased expression of Na+-K+-2Cl- co-transporter isoform 1 (NKCC1), and the transition of GABAergic signaling from excitatory to inhibitory occurs before birth in the rat spinal cord and spreads rostrally according to the developmental changes in cation-chloride co-transporter expression. We previously showed that midazolam activates the hippocampal CA3 area and induces less sedation in neonatal rats compared with adolescent rats in an NKCC1-dependent manner. In the present study, we tested the hypothesis that propofol-induced loss of righting reflex (LORR) but not immobilizing actions are modulated by NKCC1-dependent mechanisms and reduced in neonatal rats compared with adolescent rats. We estimated neuronal activity in the cortex, hippocampus and thalamus after propofol administration with or without bumetanide, an NKCC1 inhibitor, by immunostaining of phosphorylated cyclic adenosine monophosphate-response element binding protein (pCREB). We studied effects of bumetanide on propofol-induced LORR and immobilizing actions in postnatal day 7 and 28 (P7 and P28) rats. The pCREB expression in the cortex (P = 0.001) and hippocampus (P = 0.01) was significantly greater in the rats receiving propofol only than in the rats receiving propofol plus bumetanide at P 7. Propofol-induced LORR or immobilizing effects did not differ significantly between P7 and P28. Bumetanide significantly enhanced propofol-induced LORR (P = 0.031) but not immobilization in P7 rats. These results are partially consistent with our hypothesis. They suggest that propofol may activate the rostral but not caudal central nervous system dependently on NKCC1, and these differential actions may underlie the different properties of sedative and immobilizing actions observed in neonatal rats.
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Affiliation(s)
- Yukihide Koyama
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Anesthesiology, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan
- * E-mail:
| | - Tomio Andoh
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Anesthesiology, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan
| | - Yoshinori Kamiya
- Department of Anesthesiology, Niigata University Graduate School of Medicine, Niigata, Japan
| | - Tomoyuki Miyazaki
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Koichi Maruyama
- Department of Anesthesiology, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan
| | - Takayuki Kariya
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takahisa Goto
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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22
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The neural control of respiration in lampreys. Respir Physiol Neurobiol 2016; 234:14-25. [PMID: 27562521 DOI: 10.1016/j.resp.2016.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 08/08/2016] [Accepted: 08/21/2016] [Indexed: 11/24/2022]
Abstract
This review focuses on past and recent findings that have contributed to characterize the neural networks controlling respiration in the lamprey, a basal vertebrate. As in other vertebrates, respiration in lampreys is generated centrally in the brainstem. It is characterized by the presence of a fast and a slow respiratory rhythm. The anatomical and the basic physiological properties of the neural networks underlying the generation of the fast rhythm have been more thoroughly investigated; less is known about the generation of the slow respiratory rhythm. Comparative aspects with respiratory generators in other vertebrates as well as the mechanisms of modulation of respiration in association with locomotion are discussed.
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Zelenin PV, Lyalka VF, Hsu LJ, Orlovsky GN, Deliagina TG. Effects of acute spinalization on neurons of postural networks. Sci Rep 2016; 6:27372. [PMID: 27302149 PMCID: PMC4908393 DOI: 10.1038/srep27372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 05/18/2016] [Indexed: 11/15/2022] Open
Abstract
Postural limb reflexes (PLRs) represent a substantial component of postural corrections. Spinalization results in loss of postural functions, including disappearance of PLRs. The aim of the present study was to characterize the effects of acute spinalization on two populations of spinal neurons (F and E) mediating PLRs, which we characterized previously. For this purpose, in decerebrate rabbits spinalized at T12, responses of interneurons from L5 to stimulation causing PLRs before spinalization, were recorded. The results were compared to control data obtained in our previous study. We found that spinalization affected the distribution of F- and E-neurons across the spinal grey matter, caused a significant decrease in their activity, as well as disturbances in processing of posture-related sensory inputs. A two-fold decrease in the proportion of F-neurons in the intermediate grey matter was observed. Location of populations of F- and E-neurons exhibiting significant decrease in their activity was determined. A dramatic decrease of the efficacy of sensory input from the ipsilateral limb to F-neurons, and from the contralateral limb to E-neurons was found. These changes in operation of postural networks underlie the loss of postural control after spinalization, and represent a starting point for the development of spasticity.
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Affiliation(s)
- Pavel V. Zelenin
- Department of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
| | - Vladimir F. Lyalka
- Department of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
| | - Li-Ju Hsu
- Department of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
| | - Grigori N. Orlovsky
- Department of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
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Daghfous G, Green WW, Alford ST, Zielinski BS, Dubuc R. Sensory Activation of Command Cells for Locomotion and Modulatory Mechanisms: Lessons from Lampreys. Front Neural Circuits 2016; 10:18. [PMID: 27047342 PMCID: PMC4801879 DOI: 10.3389/fncir.2016.00018] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/07/2016] [Indexed: 11/13/2022] Open
Abstract
Sensorimotor transformation is one of the most fundamental and ubiquitous functions of the central nervous system (CNS). Although the general organization of the locomotor neural circuitry is relatively well understood, less is known about its activation by sensory inputs and its modulation. Utilizing the lamprey model, a detailed understanding of sensorimotor integration in vertebrates is emerging. In this article, we explore how the vertebrate CNS integrates sensory signals to generate motor behavior by examining the pathways and neural mechanisms involved in the transformation of cutaneous and olfactory inputs into motor output in the lamprey. We then review how 5-hydroxytryptamine (5-HT) acts on these systems by modulating both sensory inputs and motor output. A comprehensive review of this fundamental topic should provide a useful framework in the fields of motor control, sensorimotor integration and neuromodulation.
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Affiliation(s)
- Gheylen Daghfous
- Groupe de Recherche en Activité Physique Adaptée, Département des Sciences de l'Activité Physique, Université du Québec à MontréalMontréal, QC, Canada; Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de MontréalMontréal, QC, Canada
| | - Warren W Green
- Department of Biological Sciences and Great Lakes Institute for Environmental Research, University of Windsor Windsor, ON, Canada
| | - Simon T Alford
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago Chicago, IL, USA
| | - Barbara S Zielinski
- Department of Biological Sciences and Great Lakes Institute for Environmental Research, University of Windsor Windsor, ON, Canada
| | - Réjean Dubuc
- Groupe de Recherche en Activité Physique Adaptée, Département des Sciences de l'Activité Physique, Université du Québec à MontréalMontréal, QC, Canada; Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de MontréalMontréal, QC, Canada
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Zhang J, Xu C, Puentes DL, Seubert CN, Gravenstein N, Martynyuk AE. Role of Steroids in Hyperexcitatory Adverse and Anesthetic Effects of Sevoflurane in Neonatal Rats. Neuroendocrinology 2016; 103:440-51. [PMID: 26159049 PMCID: PMC4698089 DOI: 10.1159/000437267] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 06/28/2015] [Indexed: 11/19/2022]
Abstract
UNLABELLED Recent studies have demonstrated that long-term developmental effects of neonatal anesthesia were more prominent in males. We tested whether steroids, in general, and sex steroids, in particular, are involved in the mediation of sevoflurane-caused paradoxical cortical seizures during the early postnatal period. METHODS Cortical electroencephalograms, hippocampal synaptic activity, serum levels of steroids and the loss of the righting reflex (LORR), a marker of anesthetic effect, were measured on postnatal days 4-6 in Sprague Dawley rats of both genders exposed to 2.1% sevoflurane. RESULTS Episodes of seizures, persistent spikes in electroencephalograms and increases in serum corticosterone were similar in both genders. In the order of increasing potency, the corticosteroid receptor antagonist RU 28318, the estradiol receptor antagonist ICI 182780 and the estradiol synthesis inhibitor formestane decreased sevoflurane-induced seizures. Exogenous estradiol increased sevoflurane-caused seizures, spikes and serum levels of corticosterone. These estradiol-enhanced seizures and spikes were depressed by ICI 182780 and the NKCC1 inhibitor, bumetanide, while RU 28318 decreased seizures only. In hippocampal CA1 neurons, estradiol increased the amplitude, rise time and area under the curve of gamma-aminobutyric acid type A receptor (GABAAR)-mediated miniature postsynaptic currents. Exogenous estradiol shortened, while ICI 182780 and formestane lengthened the time needed for sevoflurane to induce LORR. CONCLUSION These findings provide evidence for gender-independent acute electroencephalographic effects of sevoflurane at this age. Corticosterone and estradiol are involved in the mediation of sevoflurane-induced seizures. Estradiol, but not corticosterone, also contributes to sevoflurane-caused spikes, by enhancing GABAAR-mediated excitation in the cortex. By increasing GABAAR-mediated inhibition in more mature caudal regions of the brain, estradiol contributes to sevoflurane-induced LORR.
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Affiliation(s)
- Jiaqiang Zhang
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL
- Department of Anesthesiology, People’s Hosptial of Zhengzhou University, Zhengzhou, P.R. China
| | - Changqing Xu
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL
| | - Dyanet L. Puentes
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL
| | - Christoph N. Seubert
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL
| | - Nikolaus Gravenstein
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL
- McKnight Brain Institute, University of Florida College of Medicine, Gainesville, FL
| | - Anatoly E. Martynyuk
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL
- McKnight Brain Institute, University of Florida College of Medicine, Gainesville, FL
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Ryczko D, Auclair F, Cabelguen JM, Dubuc R. The mesencephalic locomotor region sends a bilateral glutamatergic drive to hindbrain reticulospinal neurons in a tetrapod. J Comp Neurol 2015; 524:1361-83. [PMID: 26470600 PMCID: PMC5019149 DOI: 10.1002/cne.23911] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/01/2015] [Accepted: 10/07/2015] [Indexed: 01/09/2023]
Abstract
In vertebrates, stimulation of the mesencephalic locomotor region (MLR) on one side evokes symmetrical locomotor movements on both sides. How this occurs was previously examined in detail in a swimmer using body undulations (lamprey), but in tetrapods the downstream projections from the MLR to brainstem neurons are not fully understood. Here we examined the brainstem circuits from the MLR to identified reticulospinal neurons in the salamander Notophthalmus viridescens. Using neural tracing, we show that the MLR sends bilateral projections to the middle reticular nucleus (mRN, rostral hindbrain) and the inferior reticular nucleus (iRN, caudal hindbrain). Ca2+ imaging coupled to electrophysiology in in vitro isolated brains revealed very similar responses in reticulospinal neurons on both sides to a unilateral MLR stimulation. As the strength of MLR stimulation was increased, the responses increased in size in reticulospinal neurons of the mRN and iRN, but the responses in the iRN were smaller. Bath‐application or local microinjections of glutamatergic antagonists markedly reduced reticulospinal neuron responses, indicating that the MLR sends glutamatergic inputs to reticulospinal neurons. In addition, reticulospinal cells responded to glutamate microinjections and the size of the responses paralleled the amount of glutamate microinjected. Immunofluorescence coupled with anatomical tracing confirmed the presence of glutamatergic projections from the MLR to reticulospinal neurons. Overall, we show that the brainstem circuits activated by the MLR in the salamander are organized similarly to those previously described in lampreys, indicating that the anatomo‐physiological features of the locomotor drive are well conserved in vertebrates. J. Comp. Neurol. 524:1361–1383, 2016. © 2015 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Dimitri Ryczko
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Francois Auclair
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Jean-Marie Cabelguen
- INSERM U862 - Neurocentre Magendie, Motor System Diseases Team, Bordeaux Cedex, France
| | - Réjean Dubuc
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada.,Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Québec, Canada
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Gildenhuys A, Zandiyeh P, Kuntze G, Goldsmith P, Ronsky JL. Biomechanical Analysis of a Dynamic Stability Test System to Evoke Sway and Step Recovery. J Biomech Eng 2015; 137:104501. [DOI: 10.1115/1.4031329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/14/2015] [Indexed: 11/08/2022]
Abstract
This paper reports on the dynamic analysis and experimental validation of a method to perturb the balance of subjects in quiet standing. Electronically released weights pull the subject's waist through a specified displacement sensed by a photoelectric sensor. A dynamic model is derived that computes the force applied to the subject as a function of waist acceleration. This model accurately predicts the acceleration of mock subjects (suspended masses) with high repeatability. The validity and simplicity of this model suggest that this method can provide a standard for provocation testing on stable surfaces. Proof-of-concept trials on human subjects demonstrate that the device can be used with a force platform and motion tracking and that the device can induce both sway and step recoveries in healthy male adults.
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Affiliation(s)
- Anne Gildenhuys
- Dynastream Innovations, Inc., A Subsidiary of Garmin Ltd., Cochrane, AB T4C 0S4, Canada e-mail:
| | - Payam Zandiyeh
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada e-mail:
| | - Gregor Kuntze
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada e-mail:
| | - Peter Goldsmith
- Associate Professor Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada e-mail:
| | - Janet L. Ronsky
- Professor Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada e-mail:
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Nonnekes J, Carpenter MG, Inglis JT, Duysens J, Weerdesteyn V. What startles tell us about control of posture and gait. Neurosci Biobehav Rev 2015; 53:131-8. [PMID: 25882206 DOI: 10.1016/j.neubiorev.2015.04.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 03/12/2015] [Accepted: 04/03/2015] [Indexed: 11/17/2022]
Abstract
Recently, there has been an increase in studies evaluating startle reflexes and StartReact, many in tasks involving postural control and gait. These studies have provided important new insights. First, several experiments indicate a superimposition of startle reflex activity on the postural response during unexpected balance perturbations. Overlap in the expression of startle reflexes and postural responses emphasizes the possibility of, at least partly, a common substrate for these two types of behavior. Second, it is recognized that the range of behaviors, susceptible to StartReact, has expanded considerably. Originally this work was concentrated on simple voluntary ballistic movements, but gait initiation, online step adjustments and postural responses can be initiated earlier by a startling stimulus as well, indicating advanced motor preparation of posture and gait. Third, recent experiments on StartReact using TMS and patients with corticospinal lesions suggest that this motor preparation involves a close interaction between cortical and subcortical structures. In this review, we provide a comprehensive overview on startle reflexes, StartReact, and their interaction with posture and gait.
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Affiliation(s)
- Jorik Nonnekes
- Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Department of Rehabilitation, Nijmegen, The Netherlands.
| | - Mark G Carpenter
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - J Timothy Inglis
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Jacques Duysens
- Research Center for Movement Control and Neuroplasticity, Department of Kinesiology, KU Leuven, Leuven, Belgium
| | - Vivian Weerdesteyn
- Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Department of Rehabilitation, Nijmegen, The Netherlands; Sint Maartenskliniek Research, Nijmegen, The Netherlands
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Jacobs JV, Wu G, Kelly KM. Evidence for beta corticomuscular coherence during human standing balance: Effects of stance width, vision, and support surface. Neuroscience 2015; 298:1-11. [PMID: 25869620 DOI: 10.1016/j.neuroscience.2015.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/04/2015] [Accepted: 04/06/2015] [Indexed: 12/30/2022]
Abstract
The role of the cerebral cortex in maintaining human standing balance remains unclear. Beta corticomuscular coherence (CMC) provides a measure of communication between the sensory-motor cortex and muscle, but past literature has not demonstrated significant beta CMC during human stance. This study evaluated the effects of stance width, vision, and surface compliance on beta CMC during human stance using methods to enhance sensitivity to CMC. Ten healthy, young adults stood for three 60-s trials in each of a wide or narrow stance width while on a firm surface and in narrow stance on a foam surface, each with eyes open or closed. Beta CMC was calculated between contralateral electroencephalographic and electromyographic recordings. Electromyography was recorded from bilateral tibialis anterior and gastrocnemius lateralis muscles. CMC magnitude was defined as the average integrated area of coherence spectrum above a significance threshold. Measures of center-of-pressure (COP) sway were derived from force plates under the subjects' feet. Results of CMC from four muscles across six stance conditions (a total of 24 combinations) demonstrated significant average CMC magnitude from every subject in 20 combinations and significant average CMC magnitude in nine of 10 subjects in the remaining four combinations. The CMC magnitude was significantly larger in the wide-stance condition than in the narrow-stance condition with eyes open. No significant differences were detected when comparing eyes-open to eyes-closed conditions or when comparing firm- to foam-surface conditions. Correlations between CMC magnitude and COP sway elicited some significant relationships, but there was no consistent direction or pattern of correlation based on muscle or stance condition. Results demonstrate that significant beta CMC is evident during human standing balance, and that beta CMC is responsive to changes in mechanical, but not visual or surface, conditions.
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Affiliation(s)
- J V Jacobs
- Department of Rehabilitation and Movement Science, University of Vermont, 305 Rowell Building, 106 Carrigan Drive, Burlington, VT 05405, USA.
| | - G Wu
- Department of Rehabilitation and Movement Science, University of Vermont, 305 Rowell Building, 106 Carrigan Drive, Burlington, VT 05405, USA.
| | - K M Kelly
- Department of Rehabilitation and Movement Science, University of Vermont, 305 Rowell Building, 106 Carrigan Drive, Burlington, VT 05405, USA.
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Zelenin PV, Hsu LJ, Lyalka VF, Orlovsky GN, Deliagina TG. Putative spinal interneurons mediating postural limb reflexes provide a basis for postural control in different planes. Eur J Neurosci 2015; 41:168-81. [PMID: 25370349 PMCID: PMC4300251 DOI: 10.1111/ejn.12780] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 10/01/2014] [Accepted: 10/08/2014] [Indexed: 11/27/2022]
Abstract
The dorsal-side-up trunk orientation in standing quadrupeds is maintained by the postural system driven mainly by somatosensory inputs from the limbs. Postural limb reflexes (PLRs) represent a substantial component of this system. Earlier we described spinal neurons presumably contributing to the generation of PLRs. The first aim of the present study was to reveal trends in the distribution of neurons with different parameters of PLR-related activity across the gray matter of the spinal cord. The second aim was to estimate the contribution of PLR-related neurons with different patterns of convergence of sensory inputs from the limbs to stabilization of body orientation in different planes. For this purpose, the head and vertebral column of the decerebrate rabbit were fixed and the hindlimbs were positioned on a platform. Activity of individual neurons from L5 to L6 was recorded during PLRs evoked by lateral tilts of the platform. In addition, the neurons were tested by tilts of the platform under only the ipsilateral or only the contralateral limb, as well as during in-phase tilts of the platforms under both limbs. We found that, across the spinal gray matter, strength of PLR-related neuronal activity and sensory input from the ipsilateral limb decreased in the dorsoventral direction, while strength of the input from the contralateral limb increased. A near linear summation of tilt-related sensory inputs from different limbs was found. Functional roles were proposed for individual neurons. The obtained data present the first characterization of posture-related spinal neurons, forming a basis for studies of postural networks impaired by injury.
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Affiliation(s)
- Pavel V Zelenin
- Department of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
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Huryn TP, Blouin JS, Croft EA, Koehle MS, Van der Loos HFM. Experimental Performance Evaluation of Human Balance Control Models. IEEE Trans Neural Syst Rehabil Eng 2014; 22:1115-27. [DOI: 10.1109/tnsre.2014.2318351] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Deliagina TG, Beloozerova IN, Orlovsky GN, Zelenin PV. Contribution of supraspinal systems to generation of automatic postural responses. Front Integr Neurosci 2014; 8:76. [PMID: 25324741 PMCID: PMC4181245 DOI: 10.3389/fnint.2014.00076] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 09/14/2014] [Indexed: 11/13/2022] Open
Abstract
Different species maintain a particular body orientation in space due to activity of the closed-loop postural control system. In this review we discuss the role of neurons of descending pathways in operation of this system as revealed in animal models of differing complexity: lower vertebrate (lamprey) and higher vertebrates (rabbit and cat). In the lamprey and quadruped mammals, the role of spinal and supraspinal mechanisms in the control of posture is different. In the lamprey, the system contains one closed-loop mechanism consisting of supraspino-spinal networks. Reticulospinal (RS) neurons play a key role in generation of postural corrections. Due to vestibular input, any deviation from the stabilized body orientation leads to activation of a specific population of RS neurons. Each of the neurons activates a specific motor synergy. Collectively, these neurons evoke the motor output necessary for the postural correction. In contrast to lampreys, postural corrections in quadrupeds are primarily based not on the vestibular input but on the somatosensory input from limb mechanoreceptors. The system contains two closed-loop mechanisms - spinal and spino-supraspinal networks, which supplement each other. Spinal networks receive somatosensory input from the limb signaling postural perturbations, and generate spinal postural limb reflexes. These reflexes are relatively weak, but in intact animals they are enhanced due to both tonic supraspinal drive and phasic supraspinal commands. Recent studies of these supraspinal influences are considered in this review. A hypothesis suggesting common principles of operation of the postural systems stabilizing body orientation in a particular plane in the lamprey and quadrupeds, that is interaction of antagonistic postural reflexes, is discussed.
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Affiliation(s)
| | | | | | - Pavel V. Zelenin
- Department of Neuroscience, Karolinska InstituteStockholm, Sweden
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Tresch UA, Perreault EJ, Honeycutt CF. Startle evoked movement is delayed in older adults: implications for brainstem processing in the elderly. Physiol Rep 2014; 2:2/6/e12025. [PMID: 24907294 PMCID: PMC4208637 DOI: 10.14814/phy2.12025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Little attention has been given to how age affects the neural processing of movement within the brainstem. Since the brainstem plays a critical role in motor control throughout the whole body, having a clear understanding of deficits in brainstem function could provide important insights into movement deficits in older adults. A unique property of the startle reflex is its ability to involuntarily elicit planned movements, a phenomenon referred to as startReact. The noninvasive startReact response has previously been used to probe both brainstem utilization and motor planning. Our objective was to evaluate deficits in startReact hand extension movements in older adults. We hypothesized that startReact hand extension will be intact but delayed. Electromyography was recorded from the sternocleidomastoid (SCM) muscle to detect startle and the extensor digitorum communis (EDC) to quantify movement onset in both young (24 ± 1) and older adults (70 ± 11). Subjects were exposed to a startling loud sound when prepared to extend their hand. Trials were split into those where a startle did (SCM+) and did not (SCM−) occur. We found that startReact was intact but delayed in older adults. SCM+ onset latencies were faster than SCM− trials in both the populations, however, SCM+ onset latencies were slower in older adults compared to young (Δ = 8 msec). We conclude that the observed age‐related delay in the startReact response most likely arises from central processing delays within the brainstem. Our objective was to utilize the noninvasive startReact phenomenon, which is mediated through the brainstem, to gain insight into brainstem processing in older adults. We found that startReact hand extension was intact but delayed in older adults. The observed age‐related delay in the startReact response most likely arises from central processing delays within the brainstem. Our result that the startReact response is delayed in older individuals highlights that movements (e.g., posture, locomotion) and reflexes (e.g., long‐latency stretch reflexes) that are coordinated by the brainstem may have similar deficits in older adults.
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Affiliation(s)
| | - Eric J Perreault
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois Department of Biomedical Engineering, Northwestern University, Evanston, Illinois Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois
| | - Claire F Honeycutt
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois
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Musienko PE, Deliagina TG, Gerasimenko YP, Orlovsky GN, Zelenin PV. Limb and trunk mechanisms for balance control during locomotion in quadrupeds. J Neurosci 2014; 34:5704-16. [PMID: 24741060 PMCID: PMC3988419 DOI: 10.1523/jneurosci.4663-13.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 02/21/2014] [Accepted: 03/19/2014] [Indexed: 11/21/2022] Open
Abstract
In quadrupeds, the most critical aspect of postural control during locomotion is lateral stability. However, neural mechanisms underlying lateral stability are poorly understood. Here, we studied lateral stability in decerebrate cats walking on a treadmill with their hindlimbs. Two destabilizing factors were used: a brief lateral push of the cat and a sustained lateral tilt of the treadmill. It was found that the push caused considerable trunk bending and twisting, as well as changes in the stepping pattern, but did not lead to falling. Due to postural reactions, locomotion with normal body configuration was restored in a few steps. It was also found that the decerebrate cat could keep balance during locomotion on the laterally tilted treadmill. This postural adaptation was based on the transformation of the symmetrical locomotor pattern into an asymmetrical one, with different functional lengths of the right and left limbs. Then, we analyzed limb and trunk neural mechanisms contributing to postural control during locomotion. It was found that one of the limb mechanisms operates in the transfer phase and secures a standard (relative to the trunk) position for limb landing. Two other limb mechanisms operate in the stance phase; they counteract distortions of the locomotor pattern by regulating the limb stiffness. The trunk configuration mechanism controls the body shape on the basis of sensory information coming from trunk afferents. We suggest that postural reactions generated by these four mechanisms are integrated, thus forming a response of the whole system to perturbation of balance during locomotion.
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Affiliation(s)
- Pavel E Musienko
- Pavlov Institute of Physiology, 100034 St Petersburg, Russia, and Department of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
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Reduced StartReact effect and freezing of gait in Parkinson’s disease: two of a kind? J Neurol 2014; 261:943-50. [DOI: 10.1007/s00415-014-7304-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/24/2014] [Accepted: 02/26/2014] [Indexed: 11/26/2022]
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Abstract
Postural limb reflexes (PLRs) represent a substantial component of the postural system responsible for stabilization of dorsal-side-up trunk orientation in quadrupeds. Spinalization causes spinal shock, that is a dramatic reduction of extensor tone and spinal reflexes, including PLRs. The goal of our study was to determine changes in activity of spinal interneurons, in particular those mediating PLRs, that is caused by spinalization. For this purpose, in decerebrate rabbits, activity of individual interneurons from L5 was recorded during stimulation causing PLRs under two conditions: (1) when neurons received supraspinal influences and (2) when these influences were temporarily abolished by a cold block of spike propagation in spinal pathways at T12 ("reversible spinalization"; RS). The effect of RS, that is a dramatic reduction of PLRs, was similar to the effect of surgical spinalization. In the examined population of interneurons (n = 199), activity of 84% of them correlated with PLRs, suggesting that they contribute to PLR generation. RS affected differently individual neurons: the mean frequency decreased in 67% of neurons, increased in 15%, and did not change in 18%. Neurons with different RS effects were differently distributed across the spinal cord: 80% of inactivated neurons were located in the intermediate area and ventral horn, whereas 50% of nonaffected neurons were located in the dorsal horn. We found a group of neurons that were coactivated with extensors during PLRs before RS and exhibited a dramatic (>80%) decrease in their activity during RS. We suggest that these neurons are responsible for reduction of extensor tone and postural reflexes during spinal shock.
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Petrenko AB, Yamakura T, Sakimura K, Baba H. Defining the role of NMDA receptors in anesthesia: Are we there yet? Eur J Pharmacol 2014; 723:29-37. [DOI: 10.1016/j.ejphar.2013.11.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 11/05/2013] [Accepted: 11/24/2013] [Indexed: 12/26/2022]
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Deficits in startle-evoked arm movements increase with impairment following stroke. Clin Neurophysiol 2013; 125:1682-8. [PMID: 24411525 DOI: 10.1016/j.clinph.2013.12.102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 12/03/2013] [Accepted: 12/05/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The startle reflex elicits involuntary release of planned movements (startReact). Following stroke, startReact flexion movements are intact but startReact extension movements are impaired by task-inappropriate flexor activity impeding arm extension. Our objective was to quantify deficits in startReact elbow extension movements, particularly how these deficits are influenced by impairment. METHODS Data were collected in 8 stroke survivors performing elbow extension following two non-startling acoustic stimuli representing "get ready" and "go", respectively. Randomly, the "go" was replaced with a startling acoustic stimulus. We hypothesized that task-inappropriate flexor activity originates from unsuppressed classic startle reflex. We expected that increasing damage to the cortex (increasing impairment) would relate to increasing task-inappropriate flexor activity causing poor elbow extension movement and target acquisition. RESULTS Task-inappropriate flexor activity increased with impairment resulting in larger flexion deflections away from the subjects' intended target corresponding to decreased target acquisition. CONCLUSIONS We conclude that the task-inappropriate flexor activity likely results from cortical or corticospinal damage leading to an unsuppressed or hypermetric classic startle reflex that interrupts startReact elbow extension. SIGNIFICANCE Given startReact's functional role in compensation during environmental disturbances, our results may have important implications for our understanding deficits in stroke survivor's response to unexpected environmental disturbances.
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Honeycutt CF, Kharouta M, Perreault EJ. Evidence for reticulospinal contributions to coordinated finger movements in humans. J Neurophysiol 2013; 110:1476-83. [PMID: 23825395 DOI: 10.1152/jn.00866.2012] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The reticulospinal tract was recently shown to have synaptic connections to the intrinsic muscles of the fingers in nonhuman primates, indicating it may contribute to hand function long thought to be controlled exclusively through corticospinal pathways. Our objective was to obtain evidence supporting the hypothesis that these same anatomical connections exist in humans. startReact, an involuntary release of a planned movement via the startle reflex, provides a noninvasive means to examine the reticulospinal tract in humans. We found that startReact was triggered during coordinated grasp but not individuated finger movements. This result suggests that the reticulospinal tract does have connections to the intrinsic muscles of the fingers in humans but its functional role is limited to coordinated movement of the whole hand. These results do not diminish the well-established role of corticospinal pathways in the control of hand movement. Indeed, they cement the significance of corticospinal pathways in individuated finger movement control. Still, these results point to an updated and expanded view of distal hand control where reticulospinal and corticospinal pathways work in parallel to generate a large repertoire of diverse, coordinated movement in the hand. Finally, the presence of reticulospinal pathways to the muscles of the hand makes this pathway an attractive therapeutic target for clinical populations where the corticospinal tract is absent or injured.
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Ravichandran VJ, Honeycutt CF, Shemmell J, Perreault EJ. Instruction-dependent modulation of the long-latency stretch reflex is associated with indicators of startle. Exp Brain Res 2013; 230:59-69. [PMID: 23811739 DOI: 10.1007/s00221-013-3630-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 06/18/2013] [Indexed: 12/01/2022]
Abstract
Long-latency responses elicited by postural perturbation are modulated by how a subject is instructed to respond to the perturbation, yet the neural pathways responsible for this modulation remain unclear. The goal of this study was to determine whether instruction-dependent modulation is associated with activity in brainstem pathways contributing to startle. Our hypothesis was that elbow perturbations can evoked startle, indicated by activity in the sternocleidomastoid muscle (SCM). Perturbation responses were compared to those elicited by a loud acoustic stimulus, known to elicit startle. Postural perturbations and startling acoustic stimuli both evoked SCM activity, but only when a ballistic elbow extension movement was planned. Both stimuli triggered SCM activity with the same probability. When SCM activity was present, there was an associated early onset of triceps electromyographic (EMG), as required for the planned movement. This early EMG onset occurred at a time often attributed to long-latency stretch reflexes (75-100 ms). The nature of the perturbation-triggered EMG (excitatory or inhibitory) was independent of the perturbation direction (flexion or extension) indicating that it was not a feedback response appropriate for returning the limb to its original position. The net EMG response to perturbations delivered after a movement had been planned could be explained as the sum of a stretch reflex opposing the perturbation and a startle-evoked response associated with the prepared movement. These results demonstrate that rapid perturbations can trigger early release of a planned ballistic movement, and that this release is associated with activity in the brainstem pathways contributing to startle reflexes.
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Honeycutt CF, Perreault EJ. Planning of ballistic movement following stroke: insights from the startle reflex. PLoS One 2012; 7:e43097. [PMID: 22952634 PMCID: PMC3431358 DOI: 10.1371/journal.pone.0043097] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 07/17/2012] [Indexed: 11/18/2022] Open
Abstract
Following stroke, reaching movements are slow, segmented, and variable. It is unclear if these deficits result from a poorly constructed movement plan or an inability to voluntarily execute an appropriate plan. The acoustic startle reflex provides a means to initiate a motor plan involuntarily. In the presence of a movement plan, startling acoustic stimulus triggers non-voluntary early execution of planned movement, a phenomenon known as the startReact response. In unimpaired individuals, the startReact response is identical to a voluntarily initiated movement, except that it is elicited 30–40 ms. As the startReact response is thought to be mediated by brainstem pathways, we hypothesized that the startReact response is intact in stroke subjects. If startReact is intact, it may be possible to elicit more task-appropriate patterns of muscle activation than can be elicited voluntarily. We found that startReact responses were intact following stroke. Responses were initiated as rapidly as those in unimpaired subjects, and with muscle coordination patterns resembling those seen during unimpaired volitional movements. Results were striking for elbow flexion movements, which demonstrated no significant differences between the startReact responses elicited in our stroke and unimpaired subject groups. The results during planned extension movements were less straightforward for stroke subjects, since the startReact response exhibited task inappropriate activity in the flexors. This inappropriate activity diminished over time. This adaptation suggests that the inappropriate activity was transient in nature and not related to the underlying movement plan. We hypothesize that the task-inappropriate flexor activity during extension results from an inability to suppress the classic startle reflex, which primarily influences flexor muscles and adapts rapidly with successive stimuli. These results indicate that stroke subjects are capable of planning ballistic elbow movements, and that when these planned movements are involuntarily executed they can be as rapid and appropriate as those in unimpaired individuals.
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Affiliation(s)
- Claire Fletcher Honeycutt
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois, United States of America.
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Hsu LJ, Zelenin PV, Orlovsky GN, Deliagina TG. Effects of galvanic vestibular stimulation on postural limb reflexes and neurons of spinal postural network. J Neurophysiol 2012; 108:300-13. [PMID: 22514291 DOI: 10.1152/jn.00041.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Quadrupeds maintain the dorsal side up body orientation due to the activity of the postural control system driven by limb mechanoreceptors. Binaural galvanic vestibular stimulation (GVS) causes a lateral body sway toward the anode. Previously, we have shown that this new position is actively stabilized, suggesting that GVS changes a set point in the reflex mechanisms controlling body posture. The aim of the present study was to reveal the underlying neuronal mechanisms. Experiments were performed on decerebrate rabbits. The vertebral column was rigidly fixed, whereas hindlimbs were positioned on a platform. Periodic lateral tilts of the platform caused postural limb reflexes (PLRs): activation of extensors in the loaded and flexing limb and a decrease in extensor activity in the opposite (unloaded and extending) limb. Putative spinal interneurons were recorded in segments L4-L5 during PLRs, with and without GVS. We have found that GVS enhanced PLRs on the cathode side and reduced them on the anode side. This asymmetry in PLRs can account for changes in the stabilized body orientation observed in normal rabbits subjected to continuous GVS. Responses to platform tilts (frequency modulation) were observed in 106 spinal neurons, suggesting that they can contribute to PLR generation. Two neuron groups were active in opposite phases of the tilt cycle of the ipsi-limb: F-neurons in the flexion phase, and E-neurons in the extension phase. Neurons were driven mainly by afferent input from the ipsi-limb. If one supposes that F- and E-neurons contribute, respectively, to excitation and inhibition of extensor motoneurons, one can expect that the pattern of response to GVS in F-neurons will be similar to that in extensor muscles, whereas E-neurons will have an opposite pattern. We have found that ~40% of all modulated neurons meet this condition, suggesting that they contribute to the generation of PLRs and to the GVS-caused changes in PLRs.
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Affiliation(s)
- L-J Hsu
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
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Musienko P, Courtine G, Tibbs JE, Kilimnik V, Savochin A, Garfinkel A, Roy RR, Edgerton VR, Gerasimenko Y. Somatosensory control of balance during locomotion in decerebrated cat. J Neurophysiol 2012; 107:2072-82. [PMID: 22236709 PMCID: PMC3331606 DOI: 10.1152/jn.00730.2011] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 01/04/2012] [Indexed: 01/24/2023] Open
Abstract
Postmammillary decerebrated cats can generate stepping on a moving treadmill belt when the brain stem or spinal cord is stimulated tonically and the hindquarters are supported both vertically and laterally. While adequate propulsion seems to be generated by the hindlimbs under these conditions, the ability to sustain equilibrium during locomotion has not been examined extensively. We found that tonic epidural spinal cord stimulation (5 Hz at L5) of decerebrated cats initiated and sustained unrestrained weight-bearing hindlimb stepping for extended periods. Detailed analyses of the relationships among hindlimb muscle EMG activity and trunk and limb kinematics and kinetics indicated that the motor circuitries in decerebrated cats actively maintain equilibrium during walking, similar to that observed in intact animals. Because of the suppression of vestibular, visual, and head-neck-trunk sensory input, balance-related adjustments relied entirely on the integration of somatosensory information arising from the moving hindquarters. In addition to dynamic balance control during unperturbed locomotion, sustained stepping could be reestablished rapidly after a collapse or stumble when the hindquarters switched from a restrained to an unrestrained condition. Deflecting the body by pulling the tail laterally induced adaptive modulations in the EMG activity, step cycle features, and left-right ground reaction forces that were sufficient to maintain lateral stability. Thus the brain stem-spinal cord circuitry of decerebrated cats in response to tonic spinal cord stimulation can control dynamic balance during locomotion using only somatosensory input.
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Physiological and circuit mechanisms of postural control. Curr Opin Neurobiol 2012; 22:646-52. [PMID: 22446009 DOI: 10.1016/j.conb.2012.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/27/2012] [Accepted: 03/05/2012] [Indexed: 11/21/2022]
Abstract
The postural system maintains a specific body orientation and equilibrium during standing and during locomotion in the presence of many destabilizing factors (external and internal). Numerous studies in humans have revealed essential features of the functional organization of this system. Recent studies on different animal models have significantly supplemented human studies. They have greatly expanded our knowledge of how the control system operates, how the postural functions are distributed within different parts of CNS, and how these parts interact with each other to produce postural corrections and adjustments. This review outlines recent advances in the studies of postural control in quadrupeds, with special attention given the neuronal postural mechanisms.
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Zelenin PV, Hsu LJ, Orlovsky GN, Deliagina TG. Use of galvanic vestibular feedback to control postural orientation in decerebrate rabbits. J Neurophysiol 2012; 107:3020-6. [PMID: 22402660 DOI: 10.1152/jn.00042.2012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In quadrupeds, the dorsal-side-up body orientation during standing is maintained due to a postural system that is driven by feedback signals coming mainly from limb mechanoreceptors. In caudally decerebrated (postmammillary) rabbits, the efficacy of this system is considerably reduced. In this paper, we report that the efficacy of postural control in these animals can be restored with galvanic vestibular stimulation (GVS) applied transcutaneously to the labyrinths. In standing intact rabbits, GVS causes a lateral body sway towards the positive electrode. We used this GVS-caused sway to counteract the lateral body sway resulting from a mechanical perturbation of posture. Experiments were performed on postmammillary rabbits that stood on the tilting platform with their hindlimbs. To make the GVS value dependent on the postural perturbation (i.e., on the lateral body sway caused by tilt of the platform), an artificial feedback loop was formed in the following ways: 1) Information about the body sway was provided by a mechanical sensor; 2) The GVS current was applied when the sway exceeded a threshold value; the polarity of the current was determined by the sway direction. This simple algorithm allowed the "hybrid" postural system to maintain the dorsal-side-up orientation of the hindquarters when the platform was tilted by ± 20°. Thus, an important postural function, i.e., securing lateral stability during standing, can be restored in decerebrate rabbits with the GVS-based artificial feedback. We suggest that such a control system can compensate for the loss of lateral stability of various etiologies, and can be used for restoration of balance control in patients with impaired postural functions.
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Affiliation(s)
- P V Zelenin
- Dept. of Neuroscience, Karolinska Institute, SE-17177, Stockholm, Sweden
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Abstract
Freezing of gait (FoG) is a unique and disabling clinical phenomenon characterised by brief episodes of inability to step or by extremely short steps that typically occur on initiating gait or on turning while walking. Patients with FoG, which is a feature of parkinsonian syndromes, show variability in gait metrics between FoG episodes and a substantial reduction in step length with frequent trembling of the legs during FoG episodes. Physiological, functional imaging, and clinical-pathological studies point to disturbances in frontal cortical regions, the basal ganglia, and the midbrain locomotor region as the probable origins of FoG. Medications, deep brain stimulation, and rehabilitation techniques can alleviate symptoms of FoG in some patients, but these treatments lack efficacy in patients with advanced FoG. A better understanding of the phenomenon is needed to aid the development of effective therapeutic strategies.
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Le Ray D, Juvin L, Ryczko D, Dubuc R. Supraspinal control of locomotion. PROGRESS IN BRAIN RESEARCH 2011; 188:51-70. [DOI: 10.1016/b978-0-444-53825-3.00009-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Musienko PE, Zelenin PV, Orlovsky GN, Deliagina TG. Facilitation of postural limb reflexes with epidural stimulation in spinal rabbits. J Neurophysiol 2010; 103:1080-92. [PMID: 20018835 PMCID: PMC2822695 DOI: 10.1152/jn.00575.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 12/16/2009] [Indexed: 11/22/2022] Open
Abstract
It is known that after spinalization animals lose their ability to maintain lateral stability when standing or walking. A likely reason for this is a reduction of the postural limb reflexes (PLRs) driven by stretch and load receptors of the limbs. The aim of this study was to clarify whether spinal networks contribute to the generation of PLRs. For this purpose, first, PLRs were recorded in decerebrated rabbits before and after spinalization at T12. Second, the effects of epidural electrical stimulation (EES) at L7 on the limb reflexes were studied after spinalization. To evoke PLRs, the vertebrate column of the rabbit was fixed, whereas the hindlimbs were positioned on the platform. Periodic lateral tilts of the platform caused antiphase flexion-extension limbs movements, similar to those observed in intact animals keeping balance on the tilting platform. Before spinalization, these movements evoked PLRs: augmentation of extensor EMGs and increase of contact force during limb flexion, suggesting their stabilizing postural effects. Spinalization resulted in almost complete disappearance of PLRs. After EES, however, the PLRs reappeared and persisted for up to several minutes, although their values were reduced. The post-EES effects could be magnified by intrathecal application of quipazine (5-HT agonist) at L4-L6. Results of this study suggest that the spinal cord contains the neuronal networks underlying PLRs; they can contribute to the maintenance of lateral stability in intact subjects. In acute spinal animals, these networks can be activated by EES, suggesting that they are normally activated by a tonic supraspinal drive.
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Affiliation(s)
- P. E. Musienko
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden; and
- Pavlov Institute of Physiology, St. Petersburg, Russia
| | - P. V. Zelenin
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden; and
| | - G. N. Orlovsky
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden; and
| | - T. G. Deliagina
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden; and
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Honeycutt CF, Nichols TR. The decerebrate cat generates the essential features of the force constraint strategy. J Neurophysiol 2010; 103:3266-73. [PMID: 20089811 DOI: 10.1152/jn.00764.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cats actively respond to horizontal perturbations of the supporting surface according to the force constraint strategy. In this strategy, the force responses fall into two groups oriented in either rostral and medial directions or caudal and lateral directions, rather than in strict opposition to the direction of perturbation. When the distance between forelimbs and hindlimbs is decreased, the responses are less constrained and directed more in line with the perturbation. We have recently shown that electromyographic responses from limb muscles of the decerebrate cat resemble those obtained in the intact animal. Our objectives here were to determine whether the decerebrate cat preparation would also exhibit the force constraint strategy and whether that strategy would exhibit the characteristic dependence on limb position on the strategy. Horizontal support surface perturbations were delivered and three-dimensional exerted forces were recorded from all four limbs. Clustered force responses were generated by all four limbs and were found to be statistically indistinguishable between animals decerebrated using two different levels of transection. The directionality of the force responses was preserved throughout successive time epochs during the perturbations. In addition, the clustering of force responses increased with distance between forelimbs and hindlimbs. These results indicate that the force constraint strategy used by terrestrial animals to maintain stability can be generated without the assistance of the cerebral cortices and without prior training. This suggests an important role for the lower brain stem and spinal cord in generating an appropriate strategy to maintain stability.
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Affiliation(s)
- Claire F Honeycutt
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA.
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Honeycutt CF, Gottschall JS, Nichols TR. Electromyographic responses from the hindlimb muscles of the decerebrate cat to horizontal support surface perturbations. J Neurophysiol 2009; 101:2751-61. [PMID: 19321638 DOI: 10.1152/jn.91040.2008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The sensory and neural mechanisms underlying postural control have received much attention in recent decades but remain poorly understood. Our objectives were 1) to establish the decerebrate cat as an appropriate model for further research into the sensory mechanisms of postural control and 2) to observe what elements of the postural response can be generated by the brain stem and spinal cord. Ten animals were decerebrated using a modified premammillary technique, which consists of a premammillary decerebration that is modified with a vertical transection near the subthalamic nucleus to eliminate spontaneous locomotion. Horizontal support surface perturbations were applied to all four limbs and electromyographic recordings were collected from 14 muscles of the right hindlimb. Muscle activation was quantified with tuning curves, which compared increases and decreases in muscle activity to background and graphed the difference against perturbation direction. Parallels were drawn between these tuning curves, which were further quantified with a principal direction and breadth (range of directions of muscle activation), and data collected by other researchers from the intact animal. We found a strong similarity in the direction and breadth of the tuning curves generated in the decerebrate and intact cat. These results support our hypothesis that directionally specific tuning of muscles in response to support surface perturbations does not require the cortex, further indicating a strong role for the brain stem and spinal cord circuits in mediating directionally appropriate muscle activation patterns.
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Affiliation(s)
- Claire F Honeycutt
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332-0356, USA
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