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Oquita R, Cuello V, Uppati S, Mannuru S, Salinas D, Dobbs M, Potter-Baker KA. Moving toward elucidating alternative motor pathway structures post-stroke: the value of spinal cord neuroimaging. Front Neurol 2024; 15:1282685. [PMID: 38419695 PMCID: PMC10899520 DOI: 10.3389/fneur.2024.1282685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
Stroke results in varying levels of motor and sensory disability that have been linked to the neurodegeneration and neuroinflammation that occur in the infarct and peri-infarct regions within the brain. Specifically, previous research has identified a key role of the corticospinal tract in motor dysfunction and motor recovery post-stroke. Of note, neuroimaging studies have utilized magnetic resonance imaging (MRI) of the brain to describe the timeline of neurodegeneration of the corticospinal tract in tandem with motor function following a stroke. However, research has suggested that alternate motor pathways may also underlie disease progression and the degree of functional recovery post-stroke. Here, we assert that expanding neuroimaging techniques beyond the brain could expand our knowledge of alternate motor pathway structure post-stroke. In the present work, we will highlight findings that suggest that alternate motor pathways contribute to post-stroke motor dysfunction and recovery, such as the reticulospinal and rubrospinal tract. Then we review imaging and electrophysiological techniques that evaluate alternate motor pathways in populations of stroke and other neurodegenerative disorders. We will then outline and describe spinal cord neuroimaging techniques being used in other neurodegenerative disorders that may provide insight into alternate motor pathways post-stroke.
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Affiliation(s)
- Ramiro Oquita
- School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Victoria Cuello
- School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Sarvani Uppati
- School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Sravani Mannuru
- School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Daniel Salinas
- Department of Neuroscience, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Michael Dobbs
- Department of Clinical Neurosciences, College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Kelsey A. Potter-Baker
- Department of Neuroscience, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, United States
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Martins-Lopes V, Bellmunt A, Greguske EA, Maroto AF, Boadas-Vaello P, Llorens J. Quantitative Assessment of Anti-Gravity Reflexes to Evaluate Vestibular Dysfunction in Rats. J Assoc Res Otolaryngol 2019; 20:553-563. [PMID: 31297642 DOI: 10.1007/s10162-019-00730-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/20/2019] [Indexed: 12/18/2022] Open
Abstract
The tail-lift reflex and the air-righting reflex are anti-gravity reflexes in rats that depend on vestibular function. To obtain objective and quantitative measures of performance, we recorded these reflexes with slow-motion video in two experiments. In the first experiment, vestibular dysfunction was elicited by acute exposure to 0 (control), 400, 600, or 1000 mg/kg of 3,3'-iminodipropionitrile (IDPN), which causes dose-dependent hair cell degeneration. In the second, rats were exposed to sub-chronic IDPN in the drinking water for 0 (control), 4, or 8 weeks; this causes reversible or irreversible loss of vestibular function depending on exposure time. In the tail-lift test, we obtained the minimum angle defined during the lift and descent maneuver by the nose, the back of the neck, and the base of the tail. In the air-righting test, we obtained the time to right the head. We also obtained vestibular dysfunction ratings (VDRs) using a previously validated behavioral test battery. Each measure, VDR, tail-lift angle, and air-righting time demonstrated dose-dependent loss of vestibular function after acute IDPN and time-dependent loss of vestibular function after sub-chronic IDPN. All measures showed high correlations between each other, and maximal correlation coefficients were found between VDRs and tail-lift angles. In scanning electron microscopy evaluation of the vestibular sensory epithelia, the utricle and the saccule showed diverse pathological outcomes, suggesting that they have a different role in these reflexes. We conclude that these anti-gravity reflexes provide useful objective and quantitative measures of vestibular function in rats that are open to further development.
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Affiliation(s)
- Vanessa Martins-Lopes
- Departament de Ciències Fisiològiques, Institut de Neurociènces, Universitat de Barcelona, Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Catalunya, Spain
| | - Anna Bellmunt
- Departament de Ciències Fisiològiques, Institut de Neurociènces, Universitat de Barcelona, Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Catalunya, Spain
| | - Erin A Greguske
- Departament de Ciències Fisiològiques, Institut de Neurociènces, Universitat de Barcelona, Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Catalunya, Spain.,Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907, L'Hospitalet de Llobregat, Catalunya, Spain
| | - Alberto F Maroto
- Departament de Ciències Fisiològiques, Institut de Neurociènces, Universitat de Barcelona, Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Catalunya, Spain.,Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907, L'Hospitalet de Llobregat, Catalunya, Spain
| | - Pere Boadas-Vaello
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Departament de Ciències Mèdiques, Facultat de Medicina, Universitat de Girona, 17003, Girona, Catalunya, Spain
| | - Jordi Llorens
- Departament de Ciències Fisiològiques, Institut de Neurociènces, Universitat de Barcelona, Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Catalunya, Spain. .,Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907, L'Hospitalet de Llobregat, Catalunya, Spain.
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Murray AJ, Croce K, Belton T, Akay T, Jessell TM. Balance Control Mediated by Vestibular Circuits Directing Limb Extension or Antagonist Muscle Co-activation. Cell Rep 2019; 22:1325-1338. [PMID: 29386118 DOI: 10.1016/j.celrep.2018.01.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 11/29/2017] [Accepted: 01/03/2018] [Indexed: 11/28/2022] Open
Abstract
Maintaining balance after an external perturbation requires modification of ongoing motor plans and the selection of contextually appropriate muscle activation patterns that respect body and limb position. We have used the vestibular system to generate sensory-evoked transitions in motor programming. In the face of a rapid balance perturbation, the lateral vestibular nucleus (LVN) generates exclusive extensor muscle activation and selective early extension of the hindlimb, followed by the co-activation of extensor and flexor muscle groups. The temporal separation in EMG response to balance perturbation reflects two distinct cell types within the LVN that generate different phases of this motor program. Initially, an LVNextensor population directs an extension movement that reflects connections with extensor, but not flexor, motor neurons. A distinct LVNco-activation population initiates muscle co-activation via the pontine reticular nucleus. Thus, distinct circuits within the LVN generate different elements of a motor program involved in the maintenance of balance.
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Affiliation(s)
- Andrew J Murray
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA; Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, London, UK.
| | - Katherine Croce
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Timothy Belton
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Turgay Akay
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Thomas M Jessell
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
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McPherson LM, Dewald JPA. Differences between flexion and extension synergy-driven coupling at the elbow, wrist, and fingers of individuals with chronic hemiparetic stroke. Clin Neurophysiol 2019; 130:454-468. [PMID: 30771722 DOI: 10.1016/j.clinph.2019.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The flexion and extension synergies were quantified at the paretic elbow, forearm, wrist, and finger joints within the same group of participants for the first time. Differences in synergy expression at each of the four joints were examined, as were the ways these differences varied across the joints. METHODS Twelve post-stroke individuals with chronic moderate-to-severe hemiparesis and six age-matched controls participated. Participants generated isometric shoulder abduction (SABD) and shoulder adduction (SADD) at four submaximal levels to progressively elicit the flexion and extension synergies, respectively. Isometric joint torques and EMG were recorded from shoulder, elbow, forearm (radio-ulnar), wrist, and finger joints and muscles. RESULTS SABD elicited strong wrist and finger flexion torque that increased with shoulder torque level. SADD produced primarily wrist and finger flexion torque, but magnitudes at the wrist were less than during SABD. Findings contrasted with those at the elbow and forearm, where torques and EMG generated due to SABD and SADD were opposite in direction. CONCLUSIONS Flexion and extension synergy expression are more similar at the hand than at the shoulder and elbow. Specific bulbospinal pathways that may underlie flexion and extension synergy expression are discussed. SIGNIFICANCE Whole-limb behavior must be considered when examining paretic hand function in moderately-to-severely impaired individuals.
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Affiliation(s)
- Laura Miller McPherson
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA; Department of Physical Therapy, Nicole Wertheim College of Nursing and Health Sciences, Florida International University, Miami, FL, USA; Department of Biomedical Engineering, College of Engineering and Computing, Florida International University, Miami, FL, USA
| | - Julius P A Dewald
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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Characterization of novel dystonia musculorum mutant mice: Implications for central nervous system abnormality. Neurobiol Dis 2016; 96:271-283. [DOI: 10.1016/j.nbd.2016.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 09/20/2016] [Accepted: 09/24/2016] [Indexed: 11/19/2022] Open
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McCall AA, Miller DM, DeMayo WM, Bourdages GH, Yates BJ. Vestibular nucleus neurons respond to hindlimb movement in the conscious cat. J Neurophysiol 2016; 116:1785-1794. [PMID: 27440244 DOI: 10.1152/jn.00414.2016] [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: 05/26/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
The limbs constitute the sole interface with the ground during most waking activities in mammalian species; it is therefore expected that somatosensory inputs from the limbs provide important information to the central nervous system for balance control. In the decerebrate cat model, the activity of a subset of neurons in the vestibular nuclei (VN) has been previously shown to be modulated by hindlimb movement. However, decerebration can profoundly alter the effects of sensory inputs on the activity of brain stem neurons, resulting in epiphenomenal responses. Thus, before this study, it was unclear whether and how somatosensory inputs from the limb affected the activity of VN neurons in conscious animals. We recorded brain stem neuronal activity in the conscious cat and characterized the responses of VN neurons to flexion and extension hindlimb movements and to whole body vertical tilts (vestibular stimulation). Among 96 VN neurons whose activity was modulated by vestibular stimulation, the firing rate of 65 neurons (67.7%) was also affected by passive hindlimb movement. VN neurons in conscious cats most commonly encoded hindlimb movement irrespective of the direction of movement (n = 33, 50.8%), in that they responded to all flexion and extension movements of the limb. Other VN neurons overtly encoded information about the direction of hindlimb movement (n = 27, 41.5%), and the remainder had more complex responses. These data confirm that hindlimb somatosensory and vestibular inputs converge onto VN neurons of the conscious cat, suggesting that VN neurons integrate somatosensory inputs from the limbs in computations that affect motor outflow to maintain balance.
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Affiliation(s)
- Andrew A McCall
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Derek M Miller
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - William M DeMayo
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - George H Bourdages
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Bill J Yates
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania; and Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
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Basaldella E, Takeoka A, Sigrist M, Arber S. Multisensory Signaling Shapes Vestibulo-Motor Circuit Specificity. Cell 2015; 163:301-12. [DOI: 10.1016/j.cell.2015.09.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/22/2015] [Accepted: 09/01/2015] [Indexed: 12/31/2022]
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Tuszynski MH, Steward O. Concepts and methods for the study of axonal regeneration in the CNS. Neuron 2012; 74:777-91. [PMID: 22681683 PMCID: PMC3387806 DOI: 10.1016/j.neuron.2012.05.006] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2012] [Indexed: 12/22/2022]
Abstract
Progress in the field of axonal regeneration research has been like the process of axonal growth itself: there is steady progress toward reaching the target, but there are episodes of mistargeting, misguidance along false routes, and connections that must later be withdrawn. This primer will address issues in the study of axonal growth after central nervous system injury in an attempt to provide guidance toward the goal of progress in the field. We address definitions of axonal growth, sprouting and regeneration after injury, and the research tools to assess growth.
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Affiliation(s)
- Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093-0662, USA.
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Bilateral postsynaptic actions of pyramidal tract and reticulospinal neurons on feline erector spinae motoneurons. J Neurosci 2010; 30:858-69. [PMID: 20089894 DOI: 10.1523/jneurosci.4859-09.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Trunk muscles are important for postural adjustments associated with voluntary movements but little has been done to analyze mechanisms of supraspinal control of these muscles at a cellular level. The present study therefore aimed to investigate the input from pyramidal tract (PT) neurons to motoneurons of the musculus longissimus lumborum of the erector spinae and to analyze to what extent it is relayed by reticulospinal (RS) neurons. Intracellular records from motoneurons were used to evaluate effects of electrical stimulation of medullary pyramids and of axons of RS neurons descending in the medial longitudinal fasciculus (MLF). The results revealed that similar synaptic actions were evoked from the ipsilateral and contralateral PTs, including disynaptic and trisynaptic EPSPs and trisynaptic IPSPs. Stimulation of the MLF-evoked monosynaptic and disynaptic EPSPs and disynaptic or trisynaptic IPSPs in the same motoneurons. All short-latency PSPs of PT origin were abolished by transection of the MLF, while they remained after transection of PT fibers at a spinal level. Hence, RS neurons might serve as the main relay neurons of the most direct PT actions on musculus (m.) longissimus. However, longer-latency IPSPs remaining after MLF or PT spinal lesions and after ipsilateral or contralateral hemisection of spinal cord indicate that PT actions are also mediated by ipsilaterally and/or contralaterally located spinal interneurons. The bilateral effects of PT stimulation thereby provide an explanation why trunk movements after unilateral injuries of PT neurons (e.g., stroke) are impaired to a lesser degree than movements of the extremities.
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Galea MP, Hammar I, Nilsson E, Jankowska E. Bilateral postsynaptic actions of pyramidal tract and reticulospinal neurons on feline erector spinae motoneurons. J Neurosci 2010. [PMID: 20089894 DOI: 10.1158/0008-5472.can-10-4002.bone] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Trunk muscles are important for postural adjustments associated with voluntary movements but little has been done to analyze mechanisms of supraspinal control of these muscles at a cellular level. The present study therefore aimed to investigate the input from pyramidal tract (PT) neurons to motoneurons of the musculus longissimus lumborum of the erector spinae and to analyze to what extent it is relayed by reticulospinal (RS) neurons. Intracellular records from motoneurons were used to evaluate effects of electrical stimulation of medullary pyramids and of axons of RS neurons descending in the medial longitudinal fasciculus (MLF). The results revealed that similar synaptic actions were evoked from the ipsilateral and contralateral PTs, including disynaptic and trisynaptic EPSPs and trisynaptic IPSPs. Stimulation of the MLF-evoked monosynaptic and disynaptic EPSPs and disynaptic or trisynaptic IPSPs in the same motoneurons. All short-latency PSPs of PT origin were abolished by transection of the MLF, while they remained after transection of PT fibers at a spinal level. Hence, RS neurons might serve as the main relay neurons of the most direct PT actions on musculus (m.) longissimus. However, longer-latency IPSPs remaining after MLF or PT spinal lesions and after ipsilateral or contralateral hemisection of spinal cord indicate that PT actions are also mediated by ipsilaterally and/or contralaterally located spinal interneurons. The bilateral effects of PT stimulation thereby provide an explanation why trunk movements after unilateral injuries of PT neurons (e.g., stroke) are impaired to a lesser degree than movements of the extremities.
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Affiliation(s)
- Mary Pauline Galea
- Department of Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
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Stecina K, Jankowska E. Uncrossed actions of feline corticospinal tract neurones on hindlimb motoneurones evoked via ipsilaterally descending pathways. J Physiol 2007; 580:119-32. [PMID: 17255171 PMCID: PMC2075439 DOI: 10.1113/jphysiol.2006.122721] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Despite numerous investigations on the corticospinal system there is only scant information on neuronal networks mediating actions of corticospinal neurones on ipsilateral motoneurones. We have previously demonstrated double crossed pathways through which pyramidal tract neurones can influence ipsilateral motoneurones, via contralaterally descending reticulospinal neurones and spinal commissural interneurones. The aim of the present study was to examine the effects of stimulation of pyramidal tract (PT) fibres mediated via ipsilaterally descending pathways and to find out which neurones relay these effects. This was done by using intracellular recordings from 96 lumbar motoneurones in deeply anaesthetized cats. To eliminate actions of fibres descending on the side contralateral to the location of the motoneurones, the spinal cords were hemisected on this side at a low-thoracic level. Stimuli that selectively activated ipsilateral PT fibres evoked EPSPs and/or IPSPs in 34/47 motoneurones tested. These PSPs were evoked at latencies indicating that the most direct coupling between PT neurones and motoneurones in uncrossed pathways is disynaptic. Occlusion and spatial facilitation between actions evoked by stimulation of ipsilateral PT and of reticulospinal tract fibres in the ipsilateral medial longitudinal fascicle (MLF) indicated that PT actions are mediated by reticulospinal neurones with axons in the MLF. However, after transection of the MLF in the caudal medulla, stimulation of the ipsilateral PT continued to evoke EPSPs and IPSPs with characteristics similar to when the MLF was intact (in 15/49 motoneurones) suggesting the existence of parallel disynaptic pathways via other relay neurones.
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Affiliation(s)
- K Stecina
- Department of Physiology, Medicinaregatan 11, Box 432, 40530 Göteborg, Sweden
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Jankowska E, Stecina K, Cabaj A, Pettersson LG, Edgley SA. Neuronal relays in double crossed pathways between feline motor cortex and ipsilateral hindlimb motoneurones. J Physiol 2006; 575:527-41. [PMID: 16740611 PMCID: PMC1819437 DOI: 10.1113/jphysiol.2006.112425] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Coupling between pyramidal tract (PT) neurones and ipsilateral hindlimb motoneurones was investigated by recording from commissural interneurones interposed between them. Near maximal stimulation of either the left or right PT induced short latency EPSPs in more than 80% of 20 commissural interneurones that were monosynaptically excited by reticulospinal tract fibres in the medial longitudinal fascicle (MLF). The EPSPs were evoked at latencies that were only 1-2 ms longer than those of EPSPs evoked from the MLF, compatible with a disynaptic coupling between PT fibres and these commissural interneurones. EPSPs evoked by PT stimulation were frequently associated with IPSPs which either followed or preceded the EPSPs. The latencies of the IPSPs (on average about 1 ms longer than latencies of the earliest EPSPs) indicated that they were mediated via single additional inhibitory interneurones. Records from a sample of nine commissural interneurones from a different population (with monosynaptic input from group I and/or II muscle afferents, and disynaptically excited from the MLF) suggest that actions of PT fibres on such interneurones are weaker because only four of them were excited by PT stimuli and at longer latencies. By demonstrating disynaptic coupling between PT neurones and commissural interneurones via reticulospinal fibres, the results provide a direct demonstration of trisynaptic coupling in the most direct pathways between PT neurones and ipsilateral motoneurones, and thereby strengthen the proposal that the double crossed pathways between PT neurones and ipsilateral motoneurones might be used to replace crossed actions of damaged PT neurones.
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Affiliation(s)
- E Jankowska
- Department of Physiology, Medicinaregatan 11, Box 432, 405 30 Göteborg, Sweden.
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Cabaj A, Stecina K, Jankowska E. Same spinal interneurons mediate reflex actions of group Ib and group II afferents and crossed reticulospinal actions. J Neurophysiol 2006; 95:3911-22. [PMID: 16554505 PMCID: PMC1890023 DOI: 10.1152/jn.01262.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the study was to analyze interactions between neuronal networks mediating centrally initiated movements and reflex reactions evoked by peripheral afferents; specifically whether interneurons in pathways from group Ib afferents and from group II muscle afferents mediate actions of reticulospinal neurons on spinal motoneurons by contralaterally located commissural interneurons. To this end reticulospinal tract fibers were stimulated in the contralateral medial longitudinal fascicle (MLF) in chloralose-anesthetized cats in which the ipsilateral half of the spinal cord was transected rostral to the lumbosacral enlargement. In the majority of interneurons mediating reflex actions of group Ib and group II afferents, MLF stimuli evoked either excitatory or inhibitory postsynaptic potentials (EPSPs and IPSPs, respectively) or both EPSPs and IPSPs attributable to disynaptic actions by commissural interneurons. In addition, in some interneurons EPSPs were evoked at latencies compatible with monosynaptic actions of crossed axon collaterals of MLF fibers. Intracellular records from motoneurons demonstrated that both excitation and inhibition from group Ib and group II afferents are modulated by contralaterally descending reticulospinal neurons. The results lead to the conclusion that commissural interneurons activated by reticulospinal neurons affect motoneurons not only directly, but also by enhancing or weakening activation of premotor interneurons in pathways from group Ib and group II afferents. The results also show that both excitatory and inhibitory premotor interneurons are affected in this way and that commissural interneurons may assist in the selection of reflex actions of group Ib and group II afferents during centrally initiated movements.
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Affiliation(s)
- A Cabaj
- Department of Physiology, Göteborg University, Sweden
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Floeter MK, Sholomenko GN, Gossard JP, Burke RE. Disynaptic excitation from the medial longitudinal fasciculus to lumbosacral motoneurons: modulation by repetitive activation, descending pathways, and locomotion. Exp Brain Res 1993; 92:407-19. [PMID: 8454006 DOI: 10.1007/bf00229029] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Short-latency excitatory postsynaptic potentials (EPSPs) evoked by stimulation in the medial longitudinal fasciculus (MLF) were recorded intracellularly from motoneurons in the cat lumbosacral spinal cord. Monosynaptic and disynaptic EPSPs occurred in most flexor and extensor motoneurons studied. These EPSPs resulted from the activation of fast (> 100 m/s) descending axons from the MLF to the spinal cord. Several features distinguished monosynaptic and disynaptic MLF EPSPs. Disynaptic EPSPs exhibited temporal facilitation during short trains of stimulation, whereas monosynaptic EPSPs did not. Disynaptic EPSPs, but not monosynaptic EPSPs, were also facilitated by stimulation of the pyramidal tract and the mesencephalic locomotor region. However, disynaptic MLF EPSPs exhibited little or no facilitation when conditioned by short-latency cutaneous pathways. During fictive locomotion, the amplitude of disynaptic MLF EPSPs was modulated, with maximal amplitudes during the step cycle phase when the recorded motoneuron was active, resulting in reciprocal patterns of modulation of flexors and extensors. No comparable change was seen in the amplitude of monosynaptic MLF EPSPs during fictive stepping. These data suggest that the central pattern generator for locomotion modulates disynaptic MLF excitation at a premotoneuronal level in a phase-dependent manner. The effects of lesions made in the MLF and thoracic cord suggest that the interneurons in the disynaptic pathway from the MLF to motoneurons reside in the lumbosacral cord.
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Affiliation(s)
- M K Floeter
- Laboratory of Neural Control, NINDS, National Institutes of Health, Bethesda, MD 20892
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Kelland MD, Asdourian D. Pedunculopontine tegmental nucleus-induced inhibition of muscle activity in the rat. Behav Brain Res 1989; 34:213-34. [PMID: 2789701 DOI: 10.1016/s0166-4328(89)80103-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The connections of the pedunculopontine tegmental nucleus (PPN) have led us to propose that this structure mediates striatally induced inhibition of muscle activity by directing basal ganglia output to an inhibitory reticulospinal system (nucleus reticularis gigantocellularis and ventralis, nrGi-V). We conducted experiments in order to examine the effects of electrical stimulation of the PPN on the activity of selected neck and shoulder muscles. PPN stimulation at low rates (0.1 Hz) elicited bilateral muscle excitation. As the rate of stimulation was increased (e.g. to 10 Hz), less excitation was observed. Anodal DC current inactivation of the nrGi-V during concurrent 10 Hz PPN stimulation resulted in an augmentation of muscle activity above the levels observed during 10 Hz PPN stimulation alone. PPN stimulation (10 Hz) also profoundly inhibited cortically-induced muscle activity. Further support for our proposal stems from increased baseline activity (0.1 Hz PPN-induced excitation) in animals with ibotenic acid lesions of the PPN as compared to normal animals. Apparently, destruction of the PPN releases the musculature from tonic and/or phasic inhibition. A model is discussed which attempts to account for both the rate-dependent changes in excitation and the inhibition of cortically induced muscle activity.
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Affiliation(s)
- M D Kelland
- Department of Psychology, Wayne State University, Detroit, MI 48202
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Elliott SG, McLaughlin CS. The yeast cell cycle: coordination of growth and division rates. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1983; 28:143-76. [PMID: 6348875 DOI: 10.1016/s0079-6603(08)60086-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Ten Donkelaar HJ. Organization of descending pathways to the spinal cord in amphibians and reptiles. PROGRESS IN BRAIN RESEARCH 1982; 57:25-67. [PMID: 7156397 DOI: 10.1016/s0079-6123(08)64123-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Molina-Negro P, Bertrand RA, Martin E, Gioani Y. The role of the vestibular system in relation to muscle tone and postural reflexes in man. Acta Otolaryngol 1980; 89:524-33. [PMID: 6969516 DOI: 10.3109/00016488009127170] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Monosynaptic excitation of motoneurons of the accessory nerve nucleus by reticulofugal impulses. NEUROPHYSIOLOGY+ 1980. [DOI: 10.1007/bf01065269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
1. The reflex connexions from muscle afferents and ventral root fibres to the motoneurones of the muscles biventer-cervicis, complexus, sternocleidomastoid, trapezius and splenius, the principal muscles involved in head movement in the cat, were studied with the technique of intracellular recording. 2. Electrical stimulation of homonymous muscle afferents of biventer-cervicis and complexus, sternocleidomastoid and trapezius, at strengths below 1.6 times threshold of the dorsal root afferent volley, produced monosynaptic e.p.s.p.s in the corresponding motoneurones. Recruitment of higher threshold muscle afferents produced additional p.s.p.s with longer central delays. 3. Stimulation of low-threshold muscle afferents did not produce any p.s.p.s in the motoneurones of the ipsilateral antagonist. Stimulation of higher threshold afferents evoked i.p.s.p.s with central delays longer than 1.6 msec, or mixed e.p.s.p.-i.p.s.p.s in the ipsilateral antagonist. 4. Mixed e.p.s.p.-i.p.s.p.s or i.p.s.p.s with central delays longer than 1.5 msec were evoked in trapezius motoneurones upon stimulation of high threshold afferents from biventer-cervicis and complexus, while stimulation of low-threshold biventercervicis and complexus afferents evoked no p.s.p.s in trapezius motoneurones. 5. Stimulation of contralateral low-threshold biventer-cervicis and complexus afferents evoked a sequence of i.p.s.p. disinhibition in sternocleidomastoid motoneurones, and vice versa, with central delays longer than 1.7 msec. 6. Stimulation of the deafferented biventer-cervicis, complexus, splenius, sternocleidomastoid and trapezius muscle nerves frequently activated interneurones in the ventral horn at monosynaptic central delays. Activation of homoynmous ventral root fibres rarely evoked p.s.p.s in biventer-cervicis, complexius, splenius or sternocleidomastoid motoneurones, while it produced disynaptic i.p.s.p.s in 80% of trapezius motoneurones. 7. It is concluded that Ia reciprocal inhibition and recurrent inhibition, two reflex circuits which are so prominent in limb segments of the spinal cord, do not play a major role in the generation of head movement. Rather, head movement may be primarily controlled from supraspinal centres.
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Thoden U, Dichgans J, Doerr M, Savides T. Direction-specific vestibular and visual modulation of fore- and hindlimb reflexes in cats. PROGRESS IN BRAIN RESEARCH 1979; 50:211-8. [PMID: 551427 DOI: 10.1016/s0079-6123(08)60821-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Thoden U, Wenzel D. Tonic cervical influences on forelimb and hindlimb monosynaptic reflexes. PROGRESS IN BRAIN RESEARCH 1979; 50:281-8. [PMID: 551433 DOI: 10.1016/s0079-6123(08)60828-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Igarashi M, Levy JK, Reschke MF, Kubo T, Watson T. Locomotor dysfunction after surgical lesions in the unilateral vestibular nuclei region in squirrel monkeys. ARCHIVES OF OTO-RHINO-LARYNGOLOGY 1978; 221:89-95. [PMID: 109072 DOI: 10.1007/bf00455879] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The present experimental results in squirrel monkeys indicated that the performance of psycho-physically advanced locomotor task (squirrel monkey rail test) was severely impaired after the placement of the medium to relatively large surgical lesions in the unilateral vestibular nuclei area, and therefore, confirmed that this brain-stem structure is essential for the signal relay and/or input coordination. The severest locomotor disability was found 10-14 days after the surgery; thereafter, squirrel monkeys showed very gradual and only limited degree of performance recovery. The post-ablative performance levels were no better than 1/5 of their pre-ablative performance levels.
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Wenzel D, Thoden U, Frank A. Forelimb reflexes modulated by tonic neck positions in cats. Pflugers Arch 1978; 374:107-13. [PMID: 566419 DOI: 10.1007/bf00581288] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The modulation of monosynaptic forelimb reflexes by tonic neck positions was investigated in cats with the head fixed. Lateral flexion of the body in a horizontal plane markedly facilitates reflexes of the deep radial nerve (DR) in the ipsilateral forelimb, while the antagonistic ulnar nerve (ULN) reflexes are strongly inhibited. Opposite effects are seen after contralaternal body movement. Dorsiflexion of the body clearly increases DR-reflexes and exerts a reciprocal although more pronounced inhibition on ULN reflexes. Opposite effects appear after ventriflexion. The reflex modulation starts with head-body displacements of approximately 5 degrees and increases with increasing angles. Furthermore reflex modulation does not depend on the intact cerebrum and cerebellum. The comparison of forelimb and hindlimb reflexes shows a decrease of the neck influences along the spinal cord.
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Thoden U, Dichgans J, Savidis T. Direction-specific optokinetic modulation of monosynaptic hind limb reflexes in cats. Exp Brain Res 1977; 30:155-60. [PMID: 304014 DOI: 10.1007/bf00237867] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The excitability of hindlimb extensor and flexor motoneurons is tonically modulated by animal tilt and a large visual stimulus rotating about the animal's line of sight. This direction-specific modulation is opposite for extensor and flexor motoneurons and opposite for optokinetic and vestibular stimuli, thus combining to a functionally significant pattern of postural reflexes.
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Abstract
In cats with the head fixed in a stereotactic frame a slight facilitation of the gastrocnemiussoleus (GS) monosynaptic reflexes in the ipsilateral hindlimb, accompanied by an inhibition of the monosynaptic reflex of the antagnostic deep peroneal nerve (DP), occurs following lateral flexion and rotation around the body axis at an angle of 25 degrees. Following dorsiflexion of the body a moderate inhibition of the extensor reflexes (GS) up to 10% and a reciprocal slight excitation in the same range of the monosynaptic reflexes of flexor muscles (DP) is recorded. On the other hand after ventriflexion of the body there is a marked inhibition in the range of 50% of all the monosynaptic extensor and flexor reflexes for all the stimulus intensities used. This inhibition can already be demonstrated in ventriflexion of 10 degrees-15 degrees. All these patterns of reflex modulation are similar in cortically intact, ischemically decorticated and precollicularly decerebrated cats. Furthermore these patterns are not essentially influenced by cerebellectomy, although all reflex amplitudes are reduced. However, the spinal reflexes can not be modulated by these body movements after acute spinalization.
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Magherini PC, Precht W, Richter A. Vestibulospinal effects on hindlimb motoneurons of the frog. Pflugers Arch 1974; 348:211-23. [PMID: 4365684 DOI: 10.1007/bf00587412] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Reticulofugal influences of interneurons in the lateral region of gray matter of the cat spinal cord. NEUROPHYSIOLOGY+ 1973. [DOI: 10.1007/bf01068002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Matsushita M, Ikeda M. Propriospinal fiber connections of the cervical motor nuclei in the cat: a light and electron microscope study. J Comp Neurol 1973; 150:1-32. [PMID: 4722145 DOI: 10.1002/cne.901500102] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Synaptic activation of thoracic spinal interneurons by reticulospinal pathways. NEUROPHYSIOLOGY+ 1973. [DOI: 10.1007/bf01062652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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ten Bruggencate G, Teichmann R, Weller E. Neuronal activity in the lateral vestibular nucleus of the cat. I. Patterns of postsynaptic potentials and discharges in deiters neurones evoked by stimulation of the spinal cord. Pflugers Arch 1972; 337:119-34. [PMID: 4675072 DOI: 10.1007/bf00587835] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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McLaughlin BJ. Propriospinal and supraspinal projections to the motor nuclei in the cat spinal cord. J Comp Neurol 1972; 144:475-500. [PMID: 5071349 DOI: 10.1002/cne.901440406] [Citation(s) in RCA: 76] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Grillner S, Hongo T. Vestibulospinal effects on motoneurones and interneurones in the lumbosacral cord. PROGRESS IN BRAIN RESEARCH 1972; 37:243-62. [PMID: 4642044 DOI: 10.1016/s0079-6123(08)63906-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Study of neuronal structures of the brain stem which produce rapid reactions in reticulo-spinal pathways. NEUROPHYSIOLOGY+ 1972. [DOI: 10.1007/bf01065494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Pompeiano O. Vestibulospinal relations: vestibular influences on gamma motoneurons and primary afferents. PROGRESS IN BRAIN RESEARCH 1972; 37:197-232. [PMID: 4264584 DOI: 10.1016/s0079-6123(08)63904-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Grillner S, Hongo T, Lund S. Convergent effects on alpha motoneurones from the vestibulospinal tract and a pathway descending in the medial longitudinal fasciculus. Exp Brain Res 1971; 12:457-79. [PMID: 5093725 DOI: 10.1007/bf00234243] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Monosynaptic excitory postsynaptic potentials in thoracic motoneurons under reticulospinal influences. NEUROPHYSIOLOGY+ 1971. [DOI: 10.1007/bf01063651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Grillner S, Hongo T, Lund S. The vestibulospinal tract. Effects on alpha-motoneurones in the lumbosacral spinal cord in the cat. Exp Brain Res 1970; 10:94-120. [PMID: 5411977 DOI: 10.1007/bf00340521] [Citation(s) in RCA: 210] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wilson VJ, Yoshida M. Monosynaptic inhibition of neck motoneurons by the medial vestibular nucleus. Exp Brain Res 1969; 9:365-80. [PMID: 5364416 DOI: 10.1007/bf00235245] [Citation(s) in RCA: 140] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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