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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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Sadeghmousavi S, Soltani Khaboushan A, Jafarnezhad-Ansariha F, Nejad-Gashti R, Farsi M, Esmaeil-Pour R, Alijani M, Majidi Zolbin M, Niknejad H, Kajbafzadeh AM. The role of spinal cord tractography in detecting lesions following selective bladder afferent and efferent fibers: A novel method for induction of neurogenic lower urinary tract dysfunction in rabbit. Neurourol Urodyn 2022; 41:1539-1552. [PMID: 35842827 DOI: 10.1002/nau.25009] [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: 03/21/2022] [Revised: 06/07/2022] [Accepted: 06/19/2022] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Neurogenic lower urinary tract dysfunction (NLUTD), a challenging disorder, is defined by lack of bladder control due to the abnormalities in neural pathways and can be classified based on the location of lesions within the nervous system, thus investigating the neural pathways can help us to know the site of the lesion and specify the class of the NLUTD. Diffusion Tensor Imaging (DTI) tractography, a noninvasive advanced imaging method, is capable of detecting central nervous system pathologies, even if routine magnetic resonance imaging shows no abnormality. Accordingly, tractography is an ideal technique to evaluate patients with NLUTD and visualize the pathology site within the spine. This study aimed to introduce a novel method of spinal cord injury (SCI) to establish NLUTD in the rabbit and to investigate the potential of tractography in tracing neural tracts of the spinal cord in an induced NLUTD animal model. MATERIALS AND METHODS An animal model of NLUTD was induced through cauterization of the spinal cord at the level T12-L1 in 12 rabbits. Then rabbits were assessed via DTI, urodynamic studies (UDS), voiding cystourethrogram (VCUG), and pathology assessments using antineurofilament 200 (NF200) antibody, anti-S100, anti-Smooth Muscle Actin, anti-Myogenin, and anti-MyoD1. RESULTS The tractography visualized lesions within spinal cord fibers. DTI parameters including fractional anisotropy (FA) value and tract density were significantly decreased (FA: p-value = 0.01, Tract density: p-value = 0.05) after injury. The mean diffusivity (MD) was insignificantly increased compared to before the injury. Also, the results of UDS and pathology assessments corroborated that applying SCI and the establishment of the NLUTD model was completely successful. CONCLUSION In the present study, we investigated the auxiliary role of tractography in detecting the spinal cord lesions in the novel established rabbit model of NLUTD. The introduced method of NLUTD induction was without the leg's neurological deficit, easily applicable, low-cost, and was accompanied by minimal surgical preparation and a satisfactory survival rate in comparison with other SCI animal models.
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Affiliation(s)
- Shaghayegh Sadeghmousavi
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alireza Soltani Khaboushan
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Students' Scientific Research Center, Tehran University of Medical Science, Tehran, Iran
| | - Fahimeh Jafarnezhad-Ansariha
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Nejad-Gashti
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Farsi
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Esmaeil-Pour
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Alijani
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoumeh Majidi Zolbin
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Niknejad
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abdol-Mohammad Kajbafzadeh
- Pediatric Urology and Regenerative Medicine Research Center, Section of Tissue Engineering and Stem Cells Therapy, Children's Hospital Medical Center, Pediatrics' Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Pediatric Urology and Regenerative Medicine Research Center, Gene, Cell and Tissue Research Institute, Childern's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
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Lyakhovetskii V, Merkulyeva N, Gorskii O, Musienko P. Simultaneous bidirectional hindlimb locomotion in decerebrate cats. Sci Rep 2021; 11:3252. [PMID: 33547397 PMCID: PMC7865075 DOI: 10.1038/s41598-021-82722-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 12/18/2020] [Indexed: 11/08/2022] Open
Abstract
We show that epidural spinal cord stimulation can elicit stable bidirectional locomotion of decerebrate cats on a split-belt treadmill. The stepping pattern of one limb was similar to unidirectional forward walking and, the other-was similar to unidirectional backward walking. This confirms that spinal and brainstem circuitry are sufficient to control such complex and extraordinary motor tasks driven by somatosensory input. Interlimb coordination during forward and backward walking was preserved in 2 out of 4 animals during 'extreme' conditions when one of the treadmill belts was stopped. Bidirectional locomotion worsened but was still possible after temporary spinalization by cooling the spinal cord on a low thoracic level. These present evidence for the great degree of the automatism for this stepping mode defined by the spinal neuronal networks.
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Affiliation(s)
- V Lyakhovetskii
- Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the RF, Poselok Pesochnyy, Leningradskaya st., 70, Saint-Petersburg, Russia, 197758
- Pavlov Institute of Physiology, Russian Academy of Sciences, emb. Makarova 6, Saint-Petersburg, Russia, 199034
| | - N Merkulyeva
- Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the RF, Poselok Pesochnyy, Leningradskaya st., 70, Saint-Petersburg, Russia, 197758
- Pavlov Institute of Physiology, Russian Academy of Sciences, emb. Makarova 6, Saint-Petersburg, Russia, 199034
- Institute of Translational Biomedicine, Saint-Petersburg State University, Universitetskaya emb. 7/9, Saint-Petersburg, Russia, 199034
| | - O Gorskii
- Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the RF, Poselok Pesochnyy, Leningradskaya st., 70, Saint-Petersburg, Russia, 197758
- Pavlov Institute of Physiology, Russian Academy of Sciences, emb. Makarova 6, Saint-Petersburg, Russia, 199034
- Institute of Translational Biomedicine, Saint-Petersburg State University, Universitetskaya emb. 7/9, Saint-Petersburg, Russia, 199034
| | - Pavel Musienko
- Pavlov Institute of Physiology, Russian Academy of Sciences, emb. Makarova 6, Saint-Petersburg, Russia, 199034.
- Institute of Translational Biomedicine, Saint-Petersburg State University, Universitetskaya emb. 7/9, Saint-Petersburg, Russia, 199034.
- Children's Surgery and Orthopedic Clinic, Saint-Petersburg State Research Institute of Phthisiopulmonology, Ministry of Healthcare of the RF, Saint-Petersburg, Russia, 191036.
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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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Duarte D, Castelo-Branco LEC, Uygur Kucukseymen E, Fregni F. Developing an optimized strategy with transcranial direct current stimulation to enhance the endogenous pain control system in fibromyalgia. Expert Rev Med Devices 2018; 15:863-873. [PMID: 30501532 PMCID: PMC6644718 DOI: 10.1080/17434440.2018.1551129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Fibromyalgia affects more than 5 million people in the United States and has a detrimental impact on individuals' quality of life. Current pharmacological treatments provide limited benefits to relieve the pain of fibromyalgia, along with a risk of adverse effects; a scenario that explains the increasing interest for multimodal approaches. A tailored strategy to focus on this dysfunctional endogenous pain inhibitory system is transcranial direct current stimulation (tDCS) of the primary motor cortex. By combining tDCS with aerobic exercise, the effects can be optimized. Areas covered: The relevant literature was reviewed and discussed the methodological issues for designing a mechanistic clinical trial to test this combined intervention. Also, we reviewed the neural control of different pathways that integrate the endogenous pain inhibitory system, as well as the effects of tDCS and aerobic exercise both alone and combined. In addition, potential neurophysiological assessments are addressed: conditioned pain modulation, temporal slow pain summation, transcranial magnetic stimulation, and electroencephalography in the context of fibromyalgia. Expert commentary: By understanding the neural mechanisms underlying pain processing and potential optimized interventions in fibromyalgia with higher accuracy, the field has an evident potential of advancement in the direction of new neuromarkers and tailored therapies.
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Affiliation(s)
- Dante Duarte
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
| | - Luis Eduardo Coutinho Castelo-Branco
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
| | - Elif Uygur Kucukseymen
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
| | - Felipe Fregni
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
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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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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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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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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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