1
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Yang HH, Brezovec BE, Serratosa Capdevila L, Vanderbeck QX, Adachi A, Mann RS, Wilson RI. Fine-grained descending control of steering in walking Drosophila. Cell 2024:S0092-8674(24)00962-0. [PMID: 39293446 DOI: 10.1016/j.cell.2024.08.033] [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: 10/31/2023] [Revised: 06/18/2024] [Accepted: 08/16/2024] [Indexed: 09/20/2024]
Abstract
Locomotion involves rhythmic limb movement patterns that originate in circuits outside the brain. Purposeful locomotion requires descending commands from the brain, but we do not understand how these commands are structured. Here, we investigate this issue, focusing on the control of steering in walking Drosophila. First, we describe different limb "gestures" associated with different steering maneuvers. Next, we identify a set of descending neurons whose activity predicts steering. Focusing on two descending cell types downstream of distinct brain networks, we show that they evoke specific limb gestures: one lengthens strides on the outside of a turn, while the other attenuates strides on the inside of a turn. Our results suggest that a single descending neuron can have opposite effects during different locomotor rhythm phases, and we identify networks positioned to implement this phase-specific gating. Together, our results show how purposeful locomotion emerges from specific, coordinated modulations of low-level patterns.
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Affiliation(s)
- Helen H Yang
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Bella E Brezovec
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA
| | | | - Quinn X Vanderbeck
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Atsuko Adachi
- Department of Biochemistry and Molecular Biophysics, Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Richard S Mann
- Department of Biochemistry and Molecular Biophysics, Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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2
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Ambrad Giovannetti E, Rancz E. Behind mouse eyes: The function and control of eye movements in mice. Neurosci Biobehav Rev 2024; 161:105671. [PMID: 38604571 DOI: 10.1016/j.neubiorev.2024.105671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/12/2024] [Accepted: 04/08/2024] [Indexed: 04/13/2024]
Abstract
The mouse visual system has become the most popular model to study the cellular and circuit mechanisms of sensory processing. However, the importance of eye movements only started to be appreciated recently. Eye movements provide a basis for predictive sensing and deliver insights into various brain functions and dysfunctions. A plethora of knowledge on the central control of eye movements and their role in perception and behaviour arose from work on primates. However, an overview of various eye movements in mice and a comparison to primates is missing. Here, we review the eye movement types described to date in mice and compare them to those observed in primates. We discuss the central neuronal mechanisms for their generation and control. Furthermore, we review the mounting literature on eye movements in mice during head-fixed and freely moving behaviours. Finally, we highlight gaps in our understanding and suggest future directions for research.
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Affiliation(s)
| | - Ede Rancz
- INMED, INSERM, Aix-Marseille University, Marseille, France.
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3
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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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4
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Juárez Tello A, van der Zouwen CI, Dejas L, Duque-Yate J, Boutin J, Medina-Ortiz K, Suresh JS, Swiegers J, Sarret P, Ryczko D. Dopamine-sensitive neurons in the mesencephalic locomotor region control locomotion initiation, stop, and turns. Cell Rep 2024; 43:114187. [PMID: 38722743 PMCID: PMC11157412 DOI: 10.1016/j.celrep.2024.114187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 03/31/2024] [Accepted: 04/17/2024] [Indexed: 06/01/2024] Open
Abstract
The locomotor role of dopaminergic neurons is traditionally attributed to their ascending projections to the basal ganglia, which project to the mesencephalic locomotor region (MLR). In addition, descending dopaminergic projections to the MLR are present from basal vertebrates to mammals. However, the neurons targeted in the MLR and their behavioral role are unknown in mammals. Here, we identify genetically defined MLR cells that express D1 or D2 receptors and control different motor behaviors in mice. In the cuneiform nucleus, D1-expressing neurons promote locomotion, while D2-expressing neurons stop locomotion. In the pedunculopontine nucleus, D1-expressing neurons promote locomotion, while D2-expressing neurons evoke ipsilateral turns. Using RNAscope, we show that MLR dopamine-sensitive neurons comprise a combination of glutamatergic, GABAergic, and cholinergic neurons, suggesting that different neurotransmitter-based cell types work together to control distinct behavioral modules. Altogether, our study uncovers behaviorally relevant cell types in the mammalian MLR based on the expression of dopaminergic receptors.
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Affiliation(s)
- Andrea Juárez Tello
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Cornelis Immanuel van der Zouwen
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Léonie Dejas
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Juan Duque-Yate
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Joël Boutin
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Katherine Medina-Ortiz
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Jacinthlyn Sylvia Suresh
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Jordan Swiegers
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Philippe Sarret
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada; Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Neurosciences Sherbrooke, Institut de Pharmacologie de Sherbrooke, Sherbrooke, QC, Canada
| | - Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada; Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Neurosciences Sherbrooke, Institut de Pharmacologie de Sherbrooke, Sherbrooke, QC, Canada.
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5
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Cregg JM, Sidhu SK, Leiras R, Kiehn O. Basal ganglia-spinal cord pathway that commands locomotor gait asymmetries in mice. Nat Neurosci 2024; 27:716-727. [PMID: 38347200 PMCID: PMC11001584 DOI: 10.1038/s41593-024-01569-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 01/05/2024] [Indexed: 04/10/2024]
Abstract
The basal ganglia are essential for executing motor actions. How the basal ganglia engage spinal motor networks has remained elusive. Medullary Chx10 gigantocellular (Gi) neurons are required for turning gait programs, suggesting that turning gaits organized by the basal ganglia are executed via this descending pathway. Performing deep brainstem recordings of Chx10 Gi Ca2+ activity in adult mice, we show that striatal projection neurons initiate turning gaits via a dominant crossed pathway to Chx10 Gi neurons on the contralateral side. Using intersectional viral tracing and cell-type-specific modulation, we uncover the principal basal ganglia-spinal cord pathway for locomotor asymmetries in mice: basal ganglia → pontine reticular nucleus, oral part (PnO) → Chx10 Gi → spinal cord. Modulating the restricted PnO → Chx10 Gi pathway restores turning competence upon striatal damage, suggesting that dysfunction of this pathway may contribute to debilitating turning deficits observed in Parkinson's disease. Our results reveal the stratified circuit architecture underlying a critical motor program.
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Affiliation(s)
- Jared M Cregg
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Simrandeep K Sidhu
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Roberto Leiras
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ole Kiehn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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6
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Lemieux M, Karimi N, Bretzner F. Functional plasticity of glutamatergic neurons of medullary reticular nuclei after spinal cord injury in mice. Nat Commun 2024; 15:1542. [PMID: 38378819 PMCID: PMC10879492 DOI: 10.1038/s41467-024-45300-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/17/2024] [Indexed: 02/22/2024] Open
Abstract
Spinal cord injury disrupts the descending command from the brain and causes a range of motor deficits. Here, we use optogenetic tools to investigate the functional plasticity of the glutamatergic reticulospinal drive of the medullary reticular formation after a lateral thoracic hemisection in female mice. Sites evoking stronger excitatory descending drive in intact conditions are the most impaired after injury, whereas those associated with a weaker drive are potentiated. After lesion, pro- and anti-locomotor activities (that is, initiation/acceleration versus stop/deceleration) are overall preserved. Activating the descending reticulospinal drive improves stepping ability on a flat surface of chronically impaired injured mice, and its priming enhances recovery of skilled locomotion on a horizontal ladder. This study highlights the resilience and capacity for reorganization of the glutamatergic reticulospinal command after injury, along with its suitability as a therapeutical target to promote functional recovery.
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Affiliation(s)
- Maxime Lemieux
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC, G1V 4G2, Canada
| | - Narges Karimi
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC, G1V 4G2, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, G1V 4G2, Canada
| | - Frederic Bretzner
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC, G1V 4G2, Canada.
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, G1V 4G2, Canada.
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7
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Morgenstern NA, Esposito MS. The Basal Ganglia and Mesencephalic Locomotor Region Connectivity Matrix. Curr Neuropharmacol 2024; 22:1454-1472. [PMID: 37559244 PMCID: PMC11097982 DOI: 10.2174/1570159x21666230809112840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/16/2023] [Accepted: 02/23/2023] [Indexed: 08/11/2023] Open
Abstract
Although classically considered a relay station for basal ganglia (BG) output, the anatomy, connectivity, and function of the mesencephalic locomotor region (MLR) were redefined during the last two decades. In striking opposition to what was initially thought, MLR and BG are actually reciprocally and intimately interconnected. New viral-based, optogenetic, and mapping technologies revealed that cholinergic, glutamatergic, and GABAergic neurons coexist in this structure, which, in addition to extending descending projections, send long-range ascending fibers to the BG. These MLR projections to the BG convey motor and non-motor information to specific synaptic targets throughout different nuclei. Moreover, MLR efferent fibers originate from precise neuronal subpopulations located in particular MLR subregions, defining independent anatomo-functional subcircuits involved in particular aspects of animal behavior such as fast locomotion, explorative locomotion, posture, forelimb- related movements, speed, reinforcement, among others. In this review, we revised the literature produced during the last decade linking MLR and BG. We conclude that the classic framework considering the MLR as a homogeneous output structure passively receiving input from the BG needs to be revisited. We propose instead that the multiple subcircuits embedded in this region should be taken as independent entities that convey relevant and specific ascending information to the BG and, thus, actively participate in the execution and tuning of behavior.
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Affiliation(s)
- Nicolás A. Morgenstern
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medicine, University of Lisbon, Instituto De Medicina Molecular João Lobo Antunes, Lisbon, Portugal
| | - Maria S. Esposito
- Department of Medical Physics, Centro Atomico Bariloche, CNEA, CONICET, Av. Bustillo 9500, San Carlos de Bariloche, Rio Negro, Argentina
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8
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Ryczko D, Dubuc R. Dopamine control of downstream motor centers. Curr Opin Neurobiol 2023; 83:102785. [PMID: 37774481 DOI: 10.1016/j.conb.2023.102785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/18/2023] [Accepted: 08/26/2023] [Indexed: 10/01/2023]
Abstract
The role of dopamine in the control of movement is traditionally associated with ascending projections to the basal ganglia. However, more recently descending dopaminergic pathways projecting to downstream brainstem motor circuits were discovered. In lampreys, salamanders, and rodents, these include projections to the downstream Mesencephalic Locomotor Region (MLR), a brainstem region controlling locomotion. Such descending dopaminergic projections could prime brainstem networks controlling movement. Other descending dopaminergic projections have been shown to reach reticulospinal cells involved in the control of locomotion. In addition, dopamine directly modulates the activity of interneurons and motoneurons. Beyond locomotion, dopaminergic inputs modulate visuomotor transformations within the optic tectum (mammalian superior colliculus). Loss of descending dopaminergic inputs will likely contribute to pathological conditions such as in Parkinson's disease.
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Affiliation(s)
- Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada; Neurosciences Sherbrooke, Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Sherbrooke, Canada.
| | - Réjean Dubuc
- Groupe de Recherche en Activité Physique Adaptée, Département des Sciences de l'Activité Physique, Université du Québec à Montréal, Montréal, Québec, Canada; Groupe de recherche sur la Signalisation Neurale et la Circuiterie, Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada.
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9
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Carbo-Tano M, Lapoix M, Jia X, Thouvenin O, Pascucci M, Auclair F, Quan FB, Albadri S, Aguda V, Farouj Y, Hillman EMC, Portugues R, Del Bene F, Thiele TR, Dubuc R, Wyart C. The mesencephalic locomotor region recruits V2a reticulospinal neurons to drive forward locomotion in larval zebrafish. Nat Neurosci 2023; 26:1775-1790. [PMID: 37667039 PMCID: PMC10545542 DOI: 10.1038/s41593-023-01418-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/24/2023] [Indexed: 09/06/2023]
Abstract
The mesencephalic locomotor region (MLR) is a brain stem area whose stimulation triggers graded forward locomotion. How MLR neurons recruit downstream vsx2+ (V2a) reticulospinal neurons (RSNs) is poorly understood. Here, to overcome this challenge, we uncovered the locus of MLR in transparent larval zebrafish and show that the MLR locus is distinct from the nucleus of the medial longitudinal fasciculus. MLR stimulations reliably elicit forward locomotion of controlled duration and frequency. MLR neurons recruit V2a RSNs via projections onto somata in pontine and retropontine areas, and onto dendrites in the medulla. High-speed volumetric imaging of neuronal activity reveals that strongly MLR-coupled RSNs are active for steering or forward swimming, whereas weakly MLR-coupled medullary RSNs encode the duration and frequency of the forward component. Our study demonstrates how MLR neurons recruit specific V2a RSNs to control the kinematics of forward locomotion and suggests conservation of the motor functions of V2a RSNs across vertebrates.
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Affiliation(s)
- Martin Carbo-Tano
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique-Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Mathilde Lapoix
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique-Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Xinyu Jia
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique-Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Olivier Thouvenin
- Institut Langevin, École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, Paris Sciences et Lettres, Centre National de la Recherche Scientifique, Paris, France
| | - Marco Pascucci
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique-Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
- Université Paris-Saclay, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Centre National de la Recherche Scientifique, NeuroSpin, Baobab, Centre d'études de Saclay, Gif-sur-Yvette, France
- The American University of Paris, Paris, France
| | - François Auclair
- Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréal, Quebec, Canada
| | - Feng B Quan
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique-Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Shahad Albadri
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris, France
| | - Vernie Aguda
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Younes Farouj
- Institute of Neuroscience, Technical University of Munich, Munich, Germany
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Kavli Institute for Brain Science, Columbia University, New York, NY, USA
| | - Ruben Portugues
- Institute of Neuroscience, Technical University of Munich, Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Filippo Del Bene
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris, France
| | - Tod R Thiele
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Réjean Dubuc
- Département de Neurosciences, Faculté de Médecine, Université de Montréal, Montréal, Quebec, Canada.
- Groupe de Recherche en Activité Physique Adaptée, Department of Exercise Science, Université du Québec à Montréal, Montréal, Quebec, Canada.
| | - Claire Wyart
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique-Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France.
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10
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Wyart C, Carbo-Tano M, Cantaut-Belarif Y, Orts-Del'Immagine A, Böhm UL. Cerebrospinal fluid-contacting neurons: multimodal cells with diverse roles in the CNS. Nat Rev Neurosci 2023; 24:540-556. [PMID: 37558908 DOI: 10.1038/s41583-023-00723-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 08/11/2023]
Abstract
The cerebrospinal fluid (CSF) is a complex solution that circulates around the CNS, and whose composition changes as a function of an animal's physiological state. Ciliated neurons that are bathed in the CSF - and thus referred to as CSF-contacting neurons (CSF-cNs) - are unusual polymodal interoceptive neurons. As chemoreceptors, CSF-cNs respond to variations in pH and osmolarity and to bacterial metabolites in the CSF. Their activation during infections of the CNS results in secretion of compounds to enhance host survival. As mechanosensory neurons, CSF-cNs operate together with an extracellular proteinaceous polymer known as the Reissner fibre to detect compression during spinal curvature. Once activated, CSF-cNs inhibit motor neurons, premotor excitatory neurons and command neurons to enhance movement speed and stabilize posture. At longer timescales, CSF-cNs instruct morphogenesis throughout life via the release of neuropeptides that act over long distances on skeletal muscle. Finally, recent evidence suggests that mouse CSF-cNs may act as neural stem cells in the spinal cord, inspiring new paths of investigation for repair after injury.
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Affiliation(s)
- Claire Wyart
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France.
| | - Martin Carbo-Tano
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France
| | - Yasmine Cantaut-Belarif
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France
| | | | - Urs L Böhm
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
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11
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Gutiérrez-Ibáñez C, Wylie DR, Altshuler DL. From the eye to the wing: neural circuits for transforming optic flow into motor output in avian flight. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:839-854. [PMID: 37542566 DOI: 10.1007/s00359-023-01663-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/07/2023]
Abstract
Avian flight is guided by optic flow-the movement across the retina of images of surfaces and edges in the environment due to self-motion. In all vertebrates, there is a short pathway for optic flow information to reach pre-motor areas: retinal-recipient regions in the midbrain encode optic flow, which is then sent to the cerebellum. One well-known role for optic flow pathways to the cerebellum is the control of stabilizing eye movements (the optokinetic response). However, the role of this pathway in controlling locomotion is less well understood. Electrophysiological and tract tracing studies are revealing the functional connectivity of a more elaborate circuit through the avian cerebellum, which integrates optic flow with other sensory signals. Here we review the research supporting this framework and identify the cerebellar output centres, the lateral (CbL) and medial (CbM) cerebellar nuclei, as two key nodes with potentially distinct roles in flight control. The CbM receives bilateral optic flow information and projects to sites in the brainstem that suggest a primary role for flight control over time, such as during forward flight. The CbL receives monocular optic flow and other types of visual information. This site provides feedback to sensory areas throughout the brain and has a strong projection the nucleus ruber, which is known to have a dominant role in forelimb muscle control. This arrangement suggests primary roles for the CbL in the control of wing morphing and for rapid maneuvers.
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Affiliation(s)
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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12
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Chacon C, Nwachukwu CV, Shahsavani N, Cowley KC, Chopek JW. Lumbar V3 interneurons provide direct excitatory synaptic input onto thoracic sympathetic preganglionic neurons, linking locomotor, and autonomic spinal systems. Front Neural Circuits 2023; 17:1235181. [PMID: 37701071 PMCID: PMC10493276 DOI: 10.3389/fncir.2023.1235181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/10/2023] [Indexed: 09/14/2023] Open
Abstract
Although sympathetic autonomic systems are activated in parallel with locomotion, the neural mechanisms mediating this coordination are incompletely understood. Sympathetic preganglionic neurons (SPNs), primarily located in the intermediate laminae of thoracic and upper lumbar segments (T1-L2), increase activation of tissues and organs that provide homeostatic and metabolic support during movement and exercise. Recent evidence suggests integration between locomotor and autonomic nuclei occurs within the brainstem, initiating both descending locomotor and sympathetic activation commands. However, both locomotor and sympathetic autonomic spinal systems can be activated independent of supraspinal input, in part due to a distributed network involving propriospinal neurons. Whether an intraspinal mechanism exists to coordinate activation of these systems is unknown. We hypothesized that ascending spinal neurons located in the lumbar region provide synaptic input to thoracic SPNs. Here, we demonstrate that synaptic contacts from locomotor-related V3 interneurons (INs) are present in all thoracic laminae. Injection of an anterograde tracer into lumbar segments demonstrated that 8-20% of glutamatergic input onto SPNs originated from lumbar V3 INs and displayed a somatotopographical organization of synaptic input. Whole cell patch clamp recording in SPNs demonstrated prolonged depolarizations or action potentials in response to optical activation of either lumbar V3 INs in spinal cord preparations or in response to optical activation of V3 terminals in thoracic slice preparations. This work demonstrates a direct intraspinal connection between lumbar locomotor and thoracic sympathetic networks and suggests communication between motor and autonomic systems may be a general function of the spinal cord.
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13
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Dubuc R, Cabelguen JM, Ryczko D. Locomotor pattern generation and descending control: a historical perspective. J Neurophysiol 2023; 130:401-416. [PMID: 37465884 DOI: 10.1152/jn.00204.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 07/20/2023] Open
Abstract
The ability to generate and control locomotor movements depends on complex interactions between many areas of the nervous system, the musculoskeletal system, and the environment. How the nervous system manages to accomplish this task has been the subject of investigation for more than a century. In vertebrates, locomotion is generated by neural networks located in the spinal cord referred to as central pattern generators. Descending inputs from the brain stem initiate, maintain, and stop locomotion as well as control speed and direction. Sensory inputs adapt locomotor programs to the environmental conditions. This review presents a comparative and historical overview of some of the neural mechanisms underlying the control of locomotion in vertebrates. We have put an emphasis on spinal mechanisms and descending control.
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Affiliation(s)
- Réjean Dubuc
- Groupe de Recherche en Activité Physique Adaptée, Département des Sciences de l'Activité Physique, Université du Québec à Montréal, Montreal, Quebec, Canada
- Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de Montréal, Montreal, Quebec, Canada
| | - Jean-Marie Cabelguen
- Institut National de la Santé et de la Recherche Médicale (INSERM) U 1215-Neurocentre Magendie, Université de Bordeaux, Bordeaux Cedex, France
| | - Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec, Canada
- Neurosciences Sherbrooke, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
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14
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Sengupta M, Bagnall MW. Spinal Interneurons: Diversity and Connectivity in Motor Control. Annu Rev Neurosci 2023; 46:79-99. [PMID: 36854318 DOI: 10.1146/annurev-neuro-083122-025325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
The spinal cord is home to the intrinsic networks for locomotion. An animal in which the spinal cord has been fully severed from the brain can still produce rhythmic, patterned locomotor movements as long as some excitatory drive is provided, such as physical, pharmacological, or electrical stimuli. Yet it remains a challenge to define the underlying circuitry that produces these movements because the spinal cord contains a wide variety of neuron classes whose patterns of interconnectivity are still poorly understood. Computational models of locomotion accordingly rely on untested assumptions about spinal neuron network element identity and connectivity. In this review, we consider the classes of spinal neurons, their interconnectivity, and the significance of their circuit connections along the long axis of the spinal cord. We suggest several lines of analysis to move toward a definitive understanding of the spinal network.
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Affiliation(s)
- Mohini Sengupta
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, USA;
| | - Martha W Bagnall
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, USA;
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15
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Zahler SH, Taylor DE, Wright BS, Wong JY, Shvareva VA, Park YA, Feinberg EH. Hindbrain modules differentially transform activity of single collicular neurons to coordinate movements. Cell 2023; 186:3062-3078.e20. [PMID: 37343561 PMCID: PMC10424787 DOI: 10.1016/j.cell.2023.05.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/10/2023] [Accepted: 05/19/2023] [Indexed: 06/23/2023]
Abstract
Seemingly simple behaviors such as swatting a mosquito or glancing at a signpost involve the precise coordination of multiple body parts. Neural control of coordinated movements is widely thought to entail transforming a desired overall displacement into displacements for each body part. Here we reveal a different logic implemented in the mouse gaze system. Stimulating superior colliculus (SC) elicits head movements with stereotyped displacements but eye movements with stereotyped endpoints. This is achieved by individual SC neurons whose branched axons innervate modules in medulla and pons that drive head movements with stereotyped displacements and eye movements with stereotyped endpoints, respectively. Thus, single neurons specify a mixture of endpoints and displacements for different body parts, not overall displacement, with displacements for different body parts computed at distinct anatomical stages. Our study establishes an approach for unraveling motor hierarchies and identifies a logic for coordinating movements and the resulting pose.
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Affiliation(s)
- Sebastian H Zahler
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David E Taylor
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Brennan S Wright
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joey Y Wong
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Varvara A Shvareva
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yusol A Park
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Evan H Feinberg
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA; Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA.
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16
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Liao SM, Kleinfeld D. A change in behavioral state switches the pattern of motor output that underlies rhythmic head and orofacial movements. Curr Biol 2023; 33:1951-1966.e6. [PMID: 37105167 PMCID: PMC10225163 DOI: 10.1016/j.cub.2023.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/27/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023]
Abstract
The breathing rhythm serves as a reference that paces orofacial motor actions and orchestrates active sensing. Past work has reported that pacing occurs solely at a fixed phase relative to sniffing. We re-evaluated this constraint as a function of exploratory behavior. Allocentric and egocentric rotations of the head and the electromyogenic activity of the motoneurons for head and orofacial movements were recorded in free-ranging rats as they searched for food. We found that a change in state from foraging to rearing is accompanied by a large phase shift in muscular activation relative to sniffing, and a concurrent change in the frequency of sniffing, so that pacing now occurs at one of the two phases. Further, head turning is biased such that an animal gathers a novel sample of its environment upon inhalation. In total, the coordination of active sensing has a previously unrealized computational complexity. This can emerge from hindbrain circuits with fixed architecture and credible synaptic time delays.
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Affiliation(s)
- Song-Mao Liao
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - David Kleinfeld
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA; Department of Neurobiology, University of California San Diego, La Jolla, CA 92093, USA.
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17
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Hérent C, Diem S, Usseglio G, Fortin G, Bouvier J. Upregulation of breathing rate during running exercise by central locomotor circuits in mice. Nat Commun 2023; 14:2939. [PMID: 37217517 DOI: 10.1038/s41467-023-38583-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 05/02/2023] [Indexed: 05/24/2023] Open
Abstract
While respiratory adaptation to exercise is compulsory to cope with the increased metabolic demand, the neural signals at stake remain poorly identified. Using neural circuit tracing and activity interference strategies in mice, we uncover here two systems by which the central locomotor network can enable respiratory augmentation in relation to running activity. One originates in the mesencephalic locomotor region (MLR), a conserved locomotor controller. Through direct projections onto the neurons of the preBötzinger complex that generate the inspiratory rhythm, the MLR can trigger a moderate increase of respiratory frequency, prior to, or even in the absence of, locomotion. The other is the lumbar enlargement of the spinal cord containing the hindlimb motor circuits. When activated, and through projections onto the retrotrapezoid nucleus (RTN), it also potently upregulates breathing rate. On top of identifying critical underpinnings for respiratory hyperpnea, these data also expand the functional implication of cell types and pathways that are typically regarded as "locomotor" or "respiratory" related.
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Affiliation(s)
- Coralie Hérent
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400, Saclay, France
- Champalimaud Research, Champalimaud Foundation, 1400-038, Lisbon, Portugal
| | - Séverine Diem
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400, Saclay, France
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, 34094, Montpellier, France
| | - Giovanni Usseglio
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400, Saclay, France
| | - Gilles Fortin
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Research University, 75005, Paris, France
| | - Julien Bouvier
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400, Saclay, France.
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18
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Hayashi M, Gullo M, Senturk G, Di Costanzo S, Nagasaki SC, Kageyama R, Imayoshi I, Goulding M, Pfaff SL, Gatto G. A spinal synergy of excitatory and inhibitory neurons coordinates ipsilateral body movements. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.21.533603. [PMID: 36993220 PMCID: PMC10055247 DOI: 10.1101/2023.03.21.533603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Innate and goal-directed movements require a high-degree of trunk and appendicular muscle coordination to preserve body stability while ensuring the correct execution of the motor action. The spinal neural circuits underlying motor execution and postural stability are finely modulated by propriospinal, sensory and descending feedback, yet how distinct spinal neuron populations cooperate to control body stability and limb coordination remains unclear. Here, we identified a spinal microcircuit composed of V2 lineage-derived excitatory (V2a) and inhibitory (V2b) neurons that together coordinate ipsilateral body movements during locomotion. Inactivation of the entire V2 neuron lineage does not impair intralimb coordination but destabilizes body balance and ipsilateral limb coupling, causing mice to adopt a compensatory festinating gait and be unable to execute skilled locomotor tasks. Taken together our data suggest that during locomotion the excitatory V2a and inhibitory V2b neurons act antagonistically to control intralimb coordination, and synergistically to coordinate forelimb and hindlimb movements. Thus, we suggest a new circuit architecture, by which neurons with distinct neurotransmitter identities employ a dual-mode of operation, exerting either synergistic or opposing functions to control different facets of the same motor behavior.
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Affiliation(s)
- Marito Hayashi
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Miriam Gullo
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Gokhan Senturk
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Biological Sciences Graduate Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92037, USA
| | - Stefania Di Costanzo
- Biological Sciences Graduate Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92037, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Shinji C. Nagasaki
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Ryoichiro Kageyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
- RIKEN Center for Brain Science, Wako 351-0198, Japan
| | - Itaru Imayoshi
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Samuel L. Pfaff
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Graziana Gatto
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Neurology Department, University Hospital of Cologne, Cologne, 50937, Germany
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19
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Roussel M, Lafrance-Zoubga D, Josset N, Lemieux M, Bretzner F. Functional contribution of mesencephalic locomotor region nuclei to locomotor recovery after spinal cord injury. Cell Rep Med 2023; 4:100946. [PMID: 36812893 PMCID: PMC9975330 DOI: 10.1016/j.xcrm.2023.100946] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/09/2022] [Accepted: 01/23/2023] [Indexed: 02/23/2023]
Abstract
Spinal cord injury (SCI) results in a disruption of information between the brain and the spinal circuit. Electrical stimulation of the mesencephalic locomotor region (MLR) can promote locomotor recovery in acute and chronic SCI rodent models. Although clinical trials are currently under way, there is still debate about the organization of this supraspinal center and which anatomic correlate of the MLR should be targeted to promote recovery. Combining kinematics, electromyographic recordings, anatomic analysis, and mouse genetics, our study reveals that glutamatergic neurons of the cuneiform nucleus contribute to locomotor recovery by enhancing motor efficacy in hindlimb muscles, and by increasing locomotor rhythm and speed on a treadmill, over ground, and during swimming in chronic SCI mice. In contrast, glutamatergic neurons of the pedunculopontine nucleus slow down locomotion. Therefore, our study identifies the cuneiform nucleus and its glutamatergic neurons as a therapeutical target to improve locomotor recovery in patients living with SCI.
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Affiliation(s)
- Marie Roussel
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - David Lafrance-Zoubga
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Nicolas Josset
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Maxime Lemieux
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Frederic Bretzner
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada; Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC G1V 4G2, Canada.
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20
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Yang W, Kanodia H, Arber S. Structural and functional map for forelimb movement phases between cortex and medulla. Cell 2023; 186:162-177.e18. [PMID: 36608651 PMCID: PMC9842395 DOI: 10.1016/j.cell.2022.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/10/2022] [Accepted: 12/05/2022] [Indexed: 01/07/2023]
Abstract
The cortex influences movement by widespread top-down projections to many nervous system regions. Skilled forelimb movements require brainstem circuitry in the medulla; however, the logic of cortical interactions with these neurons remains unexplored. Here, we reveal a fine-grained anatomical and functional map between anterior cortex (AC) and medulla in mice. Distinct cortical regions generate three-dimensional synaptic columns tiling the lateral medulla, topographically matching the dorso-ventral positions of postsynaptic neurons tuned to distinct forelimb action phases. Although medial AC (MAC) terminates ventrally and connects to forelimb-reaching-tuned neurons and its silencing impairs reaching, lateral AC (LAC) influences dorsally positioned neurons tuned to food handling, and its silencing impairs handling. Cortico-medullary neurons also extend collaterals to other subcortical structures through a segregated channel interaction logic. Our findings reveal a precise alignment between cortical location, its function, and specific forelimb-action-tuned medulla neurons, thereby clarifying interaction principles between these two key structures and beyond.
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Affiliation(s)
- Wuzhou Yang
- Biozentrum, Department of Cell Biology, University of Basel, 4056 Basel, Switzerland,Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Harsh Kanodia
- Biozentrum, Department of Cell Biology, University of Basel, 4056 Basel, Switzerland,Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Silvia Arber
- Biozentrum, Department of Cell Biology, University of Basel, 4056 Basel, Switzerland,Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland,Corresponding author
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21
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Lynch E, Dempsey B, Saleeba C, Monteiro E, Turner A, Burke PGR, Allen AM, Dampney RAL, Hildreth CM, Cornish JL, Goodchild AK, McMullan S. Descending pathways from the superior colliculus mediating autonomic and respiratory effects associated with orienting behaviour. J Physiol 2022; 600:5311-5332. [PMID: 36271640 PMCID: PMC10107157 DOI: 10.1113/jp283789] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/14/2022] [Indexed: 01/05/2023] Open
Abstract
The ability to discriminate competing external stimuli and initiate contextually appropriate behaviours is a key brain function. Neurons in the deep superior colliculus (dSC) integrate multisensory inputs and activate descending projections to premotor pathways responsible for orienting, attention and defence, behaviours which involve adjustments to respiratory and cardiovascular parameters. However, the neural pathways that subserve the physiological components of orienting are poorly understood. We report that orienting responses to optogenetic dSC stimulation are accompanied by short-latency autonomic, respiratory and electroencephalographic effects in awake rats, closely mimicking those evoked by naturalistic alerting stimuli. Physiological responses were not accompanied by detectable aversion or fear, and persisted under urethane anaesthesia, indicating independence from emotional stress. Anterograde and trans-synaptic viral tracing identified a monosynaptic pathway that links the dSC to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA), a key hub for the coordination of orienting and locomotor behaviours. In urethane-anaesthetized animals, sympathoexcitatory and cardiovascular, but not respiratory, responses to dSC stimulation were replicated by optogenetic stimulation of the dSC-GiA terminals, suggesting a likely role for this pathway in mediating the autonomic components of dSC-mediated responses. Similarly, extracellular recordings from putative GiA sympathetic premotor neurons confirmed short-latency excitatory inputs from the dSC. This pathway represents a likely substrate for autonomic components of orienting responses that are mediated by dSC neurons and suggests a mechanism through which physiological and motor components of orienting behaviours may be integrated without the involvement of higher centres that mediate affective components of defensive responses. KEY POINTS: Neurons in the deep superior colliculus (dSC) integrate multimodal sensory signals to elicit context-dependent innate behaviours that are accompanied by stereotypical cardiovascular and respiratory activities. The pathways responsible for mediating the physiological components of colliculus-mediated orienting behaviours are unknown. We show that optogenetic dSC stimulation evokes transient orienting, respiratory and autonomic effects in awake rats which persist under urethane anaesthesia. Anterograde tracing from the dSC identified projections to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA). Stimulation of this pathway recapitulated autonomic effects evoked by stimulation of dSC neurons. Electrophysiological recordings from putative GiA sympathetic premotor neurons confirmed short latency excitatory input from dSC neurons. This disynaptic dSC-GiA-spinal sympathoexcitatory pathway may underlie autonomic adjustments to salient environmental cues independent of input from higher centres.
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Affiliation(s)
- Erin Lynch
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Bowen Dempsey
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Christine Saleeba
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Eloise Monteiro
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Anita Turner
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Peter G R Burke
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Andrew M Allen
- Department of Physiology, University of Melbourne, Victoria, Australia
| | - Roger A L Dampney
- School of Medical Sciences (Physiology), University of Sydney, Sydney, New South Wales, Australia
| | - Cara M Hildreth
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Jennifer L Cornish
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Ann K Goodchild
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Simon McMullan
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
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22
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Keifer J. Emergence of In Vitro Preparations and Their Contribution to Understanding the Neural Control of Behavior in Vertebrates. J Neurophysiol 2022; 128:511-526. [PMID: 35946803 DOI: 10.1152/jn.00142.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One of the longstanding goals of the field of neuroscience is to understand the neural control of behavior in both invertebrate and vertebrate species. A series of early discoveries showed that certain motor patterns like locomotion could be generated by neuronal circuits without sensory feedback or descending control systems. These were called fictitious, or "fictive", motor programs because they could be expressed by neurons in the absence of movement. This finding lead investigators to isolate central nervous system tissue and maintain it in a dish in vitro to better study mechanisms of motor pattern generation. A period of rapid development of in vitro preparations from invertebrate species that could generate fictive motor programs from the activity of central pattern generating circuits (CPGs) emerged that was gradually followed by the introduction of such preparations from vertebrates. Here, I will review some of the notable in vitropreparations from both mammalian and non-mammalian vertebrate species developed to study the neural circuits underlying a variety of complex behaviors. This approach has been instrumental in delineating not only the cellular substrates underlying locomotion, respiration, scratching, and other behaviors, but also mechanisms underlying the modifiability of motor pathways through synaptic plasticity. In vitro preparations have had a significant impact on the field of motor systems neuroscience and the expansion of our understanding of how nervous systems control behavior. The field is ready for further advancement of this approach to explore neural substrates for variations in behavior generated by social and seasonal context, and the environment.
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Affiliation(s)
- Joyce Keifer
- Neuroscience Group, Basic Biomedical Sciences, University of South Dakota Sanford School of Medicine, Vermillion, SD, United States
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23
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Wang Z, Romanski A, Mehra V, Wang Y, Brannigan M, Campbell BC, Petsko GA, Tsoulfas P, Blackmore MG. Brain-wide analysis of the supraspinal connectome reveals anatomical correlates to functional recovery after spinal injury. eLife 2022; 11:76254. [PMID: 35838234 PMCID: PMC9345604 DOI: 10.7554/elife.76254] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 07/12/2022] [Indexed: 11/15/2022] Open
Abstract
The supraspinal connectome is essential for normal behavior and homeostasis and consists of numerous sensory, motor, and autonomic projections from brain to spinal cord. Study of supraspinal control and its restoration after damage has focused mostly on a handful of major populations that carry motor commands, with only limited consideration of dozens more that provide autonomic or crucial motor modulation. Here, we assemble an experimental workflow to rapidly profile the entire supraspinal mesoconnectome in adult mice and disseminate the output in a web-based resource. Optimized viral labeling, 3D imaging, and registration to a mouse digital neuroanatomical atlas assigned tens of thousands of supraspinal neurons to 69 identified regions. We demonstrate the ability of this approach to clarify essential points of topographic mapping between spinal levels, measure population-specific sensitivity to spinal injury, and test the relationships between region-specific neuronal sparing and variability in functional recovery. This work will spur progress by broadening understanding of essential but understudied supraspinal populations.
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Affiliation(s)
- Zimei Wang
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Adam Romanski
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Vatsal Mehra
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Yunfang Wang
- Department of Neurological Surgery, University of Miami, Miami, United States
| | - Matthew Brannigan
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Benjamin C Campbell
- Helen and Robert Appel Alzheimer's Disease Research Institute, Cornell University, New York, United States
| | - Gregory A Petsko
- Helen and Robert Appel Alzheimer's Disease Research Institute, Cornell University, New York, United States
| | - Pantelis Tsoulfas
- Department of Neurological Surgery, University of Miami, Miami, United States
| | - Murray G Blackmore
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
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24
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Flaive A, Ryczko D. From retina to motoneurons: A substrate for visuomotor transformation in salamanders. J Comp Neurol 2022; 530:2518-2536. [PMID: 35662021 PMCID: PMC9545292 DOI: 10.1002/cne.25348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 11/18/2022]
Abstract
The transformation of visual input into motor output is essential to approach a target or avoid a predator. In salamanders, visually guided orientation behaviors have been extensively studied during prey capture. However, the neural circuitry involved is not resolved. Using salamander brain preparations, calcium imaging and tracing experiments, we describe a neural substrate through which retinal input is transformed into spinal motor output. We found that retina stimulation evoked responses in reticulospinal neurons of the middle reticular nucleus, known to control steering movements in salamanders. Microinjection of glutamatergic antagonists in the optic tectum (superior colliculus in mammals) decreased the reticulospinal responses. Using tracing, we found that retina projected to the dorsal layers of the contralateral tectum, where the dendrites of neurons projecting to the middle reticular nucleus were located. In slices, stimulation of the tectal dorsal layers evoked glutamatergic responses in deep tectal neurons retrogradely labeled from the middle reticular nucleus. We then examined how tectum activation translated into spinal motor output. Tectum stimulation evoked motoneuronal responses, which were decreased by microinjections of glutamatergic antagonists in the contralateral middle reticular nucleus. Reticulospinal fibers anterogradely labeled from tracer injection in the middle reticular nucleus were preferentially distributed in proximity with the dendrites of ipsilateral motoneurons. Our work establishes a neural substrate linking visual and motor centers in salamanders. This retino‐tecto‐reticulo‐spinal circuitry is well positioned to control orienting behaviors. Our study bridges the gap between the behavioral studies and the neural mechanisms involved in the transformation of visual input into motor output in salamanders.
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Affiliation(s)
- Aurélie Flaive
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada.,Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec, Canada.,Centre d'excellence en neurosciences de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada.,Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
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25
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Wheatcroft T, Saleem AB, Solomon SG. Functional Organisation of the Mouse Superior Colliculus. Front Neural Circuits 2022; 16:792959. [PMID: 35601532 PMCID: PMC9118347 DOI: 10.3389/fncir.2022.792959] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/07/2022] [Indexed: 11/30/2022] Open
Abstract
The superior colliculus (SC) is a highly conserved area of the mammalian midbrain that is widely implicated in the organisation and control of behaviour. SC receives input from a large number of brain areas, and provides outputs to a large number of areas. The convergence and divergence of anatomical connections with different areas and systems provides challenges for understanding how SC contributes to behaviour. Recent work in mouse has provided large anatomical datasets, and a wealth of new data from experiments that identify and manipulate different cells within SC, and their inputs and outputs, during simple behaviours. These data offer an opportunity to better understand the roles that SC plays in these behaviours. However, some of the observations appear, at first sight, to be contradictory. Here we review this recent work and hypothesise a simple framework which can capture the observations, that requires only a small change to previous models. Specifically, the functional organisation of SC can be explained by supposing that three largely distinct circuits support three largely distinct classes of simple behaviours-arrest, turning towards, and the triggering of escape or capture. These behaviours are hypothesised to be supported by the optic, intermediate and deep layers, respectively.
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Affiliation(s)
| | | | - Samuel G. Solomon
- Institute of Behavioural Neuroscience, University College London, London, United Kingdom
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26
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Networking brainstem and basal ganglia circuits for movement. Nat Rev Neurosci 2022; 23:342-360. [DOI: 10.1038/s41583-022-00581-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2022] [Indexed: 12/14/2022]
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27
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Parallel locomotor control strategies in mice and flies. Curr Opin Neurobiol 2022; 73:102516. [DOI: 10.1016/j.conb.2022.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/23/2021] [Accepted: 01/06/2022] [Indexed: 12/26/2022]
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28
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Abstract
Locomotion is a universal motor behavior that is expressed as the output of many integrated brain functions. Locomotion is organized at several levels of the nervous system, with brainstem circuits acting as the gate between brain areas regulating innate, emotional, or motivational locomotion and executive spinal circuits. Here we review recent advances on brainstem circuits involved in controlling locomotion. We describe how delineated command circuits govern the start, speed, stop, and steering of locomotion. We also discuss how these pathways interface between executive circuits in the spinal cord and diverse brain areas important for context-specific selection of locomotion. A recurrent theme is the need to establish a functional connectome to and from brainstem command circuits. Finally, we point to unresolved issues concerning the integrated function of locomotor control. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Roberto Leiras
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jared M. Cregg
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ole Kiehn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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29
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Chopek JW, Zhang Y, Brownstone RM. Intrinsic brainstem circuits comprised of Chx10-expressing neurons contribute to reticulospinal output in mice. J Neurophysiol 2021; 126:1978-1990. [PMID: 34669520 PMCID: PMC8715053 DOI: 10.1152/jn.00322.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Glutamatergic reticulospinal neurons in the gigantocellular reticular nucleus (GRN) of the medullary reticular formation can function as command neurons, transmitting motor commands to spinal cord circuits to instruct movement. Recent advances in our understanding of this neuron-dense region have been facilitated by the discovery of expression of the transcriptional regulator, Chx10, in excitatory reticulospinal neurons. Here, we address the capacity of local circuitry in the GRN to contribute to reticulospinal output. We define two subpopulations of Chx10-expressing neurons in this region, based on distinct electrophysiological properties and soma size (small and large), and show that these populations correspond to local interneurons and reticulospinal neurons, respectively. Using focal release of caged glutamate combined with patch clamp recordings, we demonstrated that Chx10 neurons form microcircuits in which the Chx10 local interneurons project to and facilitate the firing of Chx10 reticulospinal neurons. We discuss the implications of these microcircuits in terms of movement selection. NEW & NOTEWORTHY Reticulospinal neurons in the medullary reticular formation integrate inputs from higher regions to effectively instruct spinal motor circuits. Using photoactivation of neurons in brainstem slices, we studied connectivity of reticular formation neurons that express the transcriptional regulator, Chx10. We show that a subpopulation of these neurons functions as local interneurons that affect descending commands. The results shed light on the internal organization and microcircuit formation of reticular formation neurons.
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Affiliation(s)
- Jeremy W Chopek
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.,Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ying Zhang
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert M Brownstone
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
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30
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Optogenetic stimulation of glutamatergic neurons in the cuneiform nucleus controls locomotion in a mouse model of Parkinson's disease. Proc Natl Acad Sci U S A 2021; 118:2110934118. [PMID: 34670837 DOI: 10.1073/pnas.2110934118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 01/22/2023] Open
Abstract
In Parkinson's disease (PD), the loss of midbrain dopaminergic cells results in severe locomotor deficits, such as gait freezing and akinesia. Growing evidence indicates that these deficits can be attributed to the decreased activity in the mesencephalic locomotor region (MLR), a brainstem region controlling locomotion. Clinicians are exploring the deep brain stimulation of the MLR as a treatment option to improve locomotor function. The results are variable, from modest to promising. However, within the MLR, clinicians have targeted the pedunculopontine nucleus exclusively, while leaving the cuneiform nucleus unexplored. To our knowledge, the effects of cuneiform nucleus stimulation have never been determined in parkinsonian conditions in any animal model. Here, we addressed this issue in a mouse model of PD, based on the bilateral striatal injection of 6-hydroxydopamine, which damaged the nigrostriatal pathway and decreased locomotor activity. We show that selective optogenetic stimulation of glutamatergic neurons in the cuneiform nucleus in mice expressing channelrhodopsin in a Cre-dependent manner in Vglut2-positive neurons (Vglut2-ChR2-EYFP mice) increased the number of locomotor initiations, increased the time spent in locomotion, and controlled locomotor speed. Using deep learning-based movement analysis, we found that the limb kinematics of optogenetic-evoked locomotion in pathological conditions were largely similar to those recorded in intact animals. Our work identifies the glutamatergic neurons of the cuneiform nucleus as a potentially clinically relevant target to improve locomotor activity in parkinsonian conditions. Our study should open avenues to develop the targeted stimulation of these neurons using deep brain stimulation, pharmacotherapy, or optogenetics.
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31
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Russo M, Ozeri-Engelhard N, Hupfeld K, Nettekoven C, Thibault S, Sedaghat-Nejad E, Buchwald D, Xing D, Zobeiri O, Kilteni K, Albert ST, Ariani G. Highlights from the 30th Annual Meeting of the Society for the Neural Control of Movement. J Neurophysiol 2021; 126:967-975. [PMID: 34406885 PMCID: PMC8560412 DOI: 10.1152/jn.00334.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/10/2021] [Indexed: 11/22/2022] Open
Affiliation(s)
- Marta Russo
- Department of Neurology, Tor Vergata Polyclinic, Rome, Italy
- Department of Biology, Northeastern University, Boston, Massachusetts
| | - Nofar Ozeri-Engelhard
- WM Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Kathleen Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Caroline Nettekoven
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Simon Thibault
- ImpAct team, Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR5292, University of Lyon 1, Lyon, France
| | - Ehsan Sedaghat-Nejad
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Daniela Buchwald
- Ottobock SE & Co. KGaA, Software & Electronics Engineering, Duderstadt, Germany
| | - David Xing
- Department of Neurobiology, Northwestern University, Evanston, Illinois
| | - Omid Zobeiri
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | | | - Scott T Albert
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Giacomo Ariani
- The Brain and Mind Institute, Western University, London, Ontario, Canada
- Department of Computer Science, Western University, London, Ontario, Canada
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32
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Chaterji S, Barik A, Sathyamurthy A. Intraspinal injection of adeno-associated viruses into the adult mouse spinal cord. STAR Protoc 2021; 2:100786. [PMID: 34505088 PMCID: PMC8414904 DOI: 10.1016/j.xpro.2021.100786] [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] [Indexed: 12/19/2022] Open
Abstract
Genetic dissection of neural circuits has been accelerated by recent advances in viral-based vectors. This protocol describes an effective approach to performing intraspinal injections of adeno-associated viruses, which can be used to label, manipulate, and monitor spinal and supraspinal neurons. By avoiding invasive laminectomies and restrictive spinal-clamping and by adopting injectable anaesthetics and tough quartz glass micropipettes, our protocol presents a time-saving and efficient approach for genetic manipulation of neural circuits nucleated in the spinal cord. For complete details on the use and execution of this protocol, please refer to Sathyamurthy et al. (2020).
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Affiliation(s)
- Shrivas Chaterji
- Centre for Neuroscience, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Arnab Barik
- Centre for Neuroscience, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Anupama Sathyamurthy
- Centre for Neuroscience, Indian Institute of Science, Bangalore, Karnataka 560012, India
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33
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Grillner S. Evolution of the vertebrate motor system - from forebrain to spinal cord. Curr Opin Neurobiol 2021; 71:11-18. [PMID: 34450468 DOI: 10.1016/j.conb.2021.07.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/12/2021] [Accepted: 07/27/2021] [Indexed: 11/29/2022]
Abstract
A comparison of the vertebrate motor systems of the oldest group of now living vertebrates (lamprey) with that of mammals shows that there are striking similarities not only in the basic organization but also with regard to synaptic properties, transmitters and neuronal properties. The lamprey dorsal pallium (cortex) has a motor, a visual and a somatosensory area, and the basal ganglia, including the dopamine system, are organized in a virtually identical way in the lamprey and rodents. This also applies to the midbrain, brainstem and spinal cord. However, during evolution additional capabilities such as systems for the control of foreleg/arms, hands and fingers have evolved. The findings suggest that when the evolutionary lineages of mammals and lamprey became separate around 500 million years ago, the blueprint of the vertebrate motor system had already evolved.
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Affiliation(s)
- Sten Grillner
- Department of Neuroscience, Karolinska Institutet, SE 17177, Stockholm, Sweden.
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34
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Lemieux M, Thiry L, Laflamme OD, Bretzner F. Role of DSCAM in the Development of Neural Control of Movement and Locomotion. Int J Mol Sci 2021; 22:ijms22168511. [PMID: 34445216 PMCID: PMC8395195 DOI: 10.3390/ijms22168511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 11/30/2022] Open
Abstract
Locomotion results in an alternance of flexor and extensor muscles between left and right limbs generated by motoneurons that are controlled by the spinal interneuronal circuit. This spinal locomotor circuit is modulated by sensory afferents, which relay proprioceptive and cutaneous inputs that inform the spatial position of limbs in space and potential contacts with our environment respectively, but also by supraspinal descending commands of the brain that allow us to navigate in complex environments, avoid obstacles, chase prey, or flee predators. Although signaling pathways are important in the establishment and maintenance of motor circuits, the role of DSCAM, a cell adherence molecule associated with Down syndrome, has only recently been investigated in the context of motor control and locomotion in the rodent. DSCAM is known to be involved in lamination and delamination, synaptic targeting, axonal guidance, dendritic and cell tiling, axonal fasciculation and branching, programmed cell death, and synaptogenesis, all of which can impact the establishment of motor circuits during development, but also their maintenance through adulthood. We discuss herein how DSCAM is important for proper motor coordination, especially for breathing and locomotion.
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Affiliation(s)
- Maxime Lemieux
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
| | - Louise Thiry
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
| | - Olivier D. Laflamme
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
| | - Frédéric Bretzner
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Université Laval, Québec, QC G1V 4G2, Canada
- Correspondence:
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35
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Guérout N. Plasticity of the Injured Spinal Cord. Cells 2021; 10:cells10081886. [PMID: 34440655 PMCID: PMC8395000 DOI: 10.3390/cells10081886] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 12/11/2022] Open
Abstract
Complete spinal cord injury (SCI) leads to permanent motor, sensitive and sensory deficits. In humans, there is currently no therapy to promote recovery and the only available treatments include surgical intervention to prevent further damage and symptomatic relief of pain and infections in the acute and chronic phases, respectively. Basically, the spinal cord is classically viewed as a nonregenerative tissue with limited plasticity. Thereby the establishment of the “glial” scar which appears within the SCI is mainly described as a hermetic barrier for axon regeneration. However, recent discoveries have shed new light on the intrinsic functional plasticity and endogenous recovery potential of the spinal cord. In this review, we will address the different aspects that the spinal cord plasticity can take on. Indeed, different experimental paradigms have demonstrated that axonal regrowth can occur even after complete SCI. Moreover, recent articles have demonstrated too that the “glial” scar is in fact composed of several cellular populations and that each of them exerts specific roles after SCI. These recent discoveries underline the underestimation of the plasticity of the spinal cord at cellular and molecular levels. Finally, we will address the modulation of this endogenous spinal cord plasticity and the perspectives of future therapeutic opportunities which can be offered by modulating the injured spinal cord microenvironment.
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Affiliation(s)
- Nicolas Guérout
- EA3830 GRHV, Institute for Research and Innovation in Biomedicine (IRIB), Normandie Université, UNIROUEN, 76000 Rouen, France
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36
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Computational Modeling of Spinal Locomotor Circuitry in the Age of Molecular Genetics. Int J Mol Sci 2021; 22:ijms22136835. [PMID: 34202085 PMCID: PMC8267724 DOI: 10.3390/ijms22136835] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/13/2022] Open
Abstract
Neuronal circuits in the spinal cord are essential for the control of locomotion. They integrate supraspinal commands and afferent feedback signals to produce coordinated rhythmic muscle activations necessary for stable locomotion. For several decades, computational modeling has complemented experimental studies by providing a mechanistic rationale for experimental observations and by deriving experimentally testable predictions. This symbiotic relationship between experimental and computational approaches has resulted in numerous fundamental insights. With recent advances in molecular and genetic methods, it has become possible to manipulate specific constituent elements of the spinal circuitry and relate them to locomotor behavior. This has led to computational modeling studies investigating mechanisms at the level of genetically defined neuronal populations and their interactions. We review literature on the spinal locomotor circuitry from a computational perspective. By reviewing examples leading up to and in the age of molecular genetics, we demonstrate the importance of computational modeling and its interactions with experiments. Moving forward, neuromechanical models with neuronal circuitry modeled at the level of genetically defined neuronal populations will be required to further unravel the mechanisms by which neuronal interactions lead to locomotor behavior.
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37
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van der Zouwen CI, Boutin J, Fougère M, Flaive A, Vivancos M, Santuz A, Akay T, Sarret P, Ryczko D. Freely Behaving Mice Can Brake and Turn During Optogenetic Stimulation of the Mesencephalic Locomotor Region. Front Neural Circuits 2021; 15:639900. [PMID: 33897379 PMCID: PMC8062873 DOI: 10.3389/fncir.2021.639900] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
A key function of the mesencephalic locomotor region (MLR) is to control the speed of forward symmetrical locomotor movements. However, the ability of freely moving mammals to integrate environmental cues to brake and turn during MLR stimulation is poorly documented. Here, we investigated whether freely behaving mice could brake or turn, based on environmental cues during MLR stimulation. We photostimulated the cuneiform nucleus (part of the MLR) in mice expressing channelrhodopsin in Vglut2-positive neurons in a Cre-dependent manner (Vglut2-ChR2-EYFP) using optogenetics. We detected locomotor movements using deep learning. We used patch-clamp recordings to validate the functional expression of channelrhodopsin and neuroanatomy to visualize the stimulation sites. In the linear corridor, gait diagram and limb kinematics were similar during spontaneous and optogenetic-evoked locomotion. In the open-field arena, optogenetic stimulation of the MLR evoked locomotion, and increasing laser power increased locomotor speed. Mice could brake and make sharp turns (~90°) when approaching a corner during MLR stimulation in the open-field arena. The speed during the turn was scaled with the speed before the turn, and with the turn angle. Patch-clamp recordings in Vglut2-ChR2-EYFP mice show that blue light evoked short-latency spiking in MLR neurons. Our results strengthen the idea that different brainstem neurons convey braking/turning and MLR speed commands in mammals. Our study also shows that Vglut2-positive neurons of the cuneiform nucleus are a relevant target to increase locomotor activity without impeding the ability to brake and turn when approaching obstacles, thus ensuring smooth and adaptable navigation. Our observations may have clinical relevance since cuneiform nucleus stimulation is increasingly considered to improve locomotion function in pathological states such as Parkinson's disease, spinal cord injury, or stroke.
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Affiliation(s)
- Cornelis Immanuel van der Zouwen
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Joël Boutin
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Maxime Fougère
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Aurélie Flaive
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Mélanie Vivancos
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Alessandro Santuz
- Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, NS, Canada.,Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Turgay Akay
- Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, NS, Canada
| | - Philippe Sarret
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC, Canada.,Centre d'excellence en neurosciences de l'Université de Sherbrooke, Sherbrooke, QC, Canada.,Institut de pharmacologie de Sherbrooke, Sherbrooke, QC, Canada
| | - Dimitri Ryczko
- Département de pharmacologie-physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC, Canada.,Centre d'excellence en neurosciences de l'Université de Sherbrooke, Sherbrooke, QC, Canada.,Institut de pharmacologie de Sherbrooke, Sherbrooke, QC, Canada
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38
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Spinal Inhibitory Interneurons: Gatekeepers of Sensorimotor Pathways. Int J Mol Sci 2021; 22:ijms22052667. [PMID: 33800863 PMCID: PMC7961554 DOI: 10.3390/ijms22052667] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/26/2021] [Accepted: 03/04/2021] [Indexed: 12/20/2022] Open
Abstract
The ability to sense and move within an environment are complex functions necessary for the survival of nearly all species. The spinal cord is both the initial entry site for peripheral information and the final output site for motor response, placing spinal circuits as paramount in mediating sensory responses and coordinating movement. This is partly accomplished through the activation of complex spinal microcircuits that gate afferent signals to filter extraneous stimuli from various sensory modalities and determine which signals are transmitted to higher order structures in the CNS and to spinal motor pathways. A mechanistic understanding of how inhibitory interneurons are organized and employed within the spinal cord will provide potential access points for therapeutics targeting inhibitory deficits underlying various pathologies including sensory and movement disorders. Recent studies using transgenic manipulations, neurochemical profiling, and single-cell transcriptomics have identified distinct populations of inhibitory interneurons which express an array of genetic and/or neurochemical markers that constitute functional microcircuits. In this review, we provide an overview of identified neural components that make up inhibitory microcircuits within the dorsal and ventral spinal cord and highlight the importance of inhibitory control of sensorimotor pathways at the spinal level.
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39
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Chang SJ, Santamaria AJ, Sanchez FJ, Villamil LM, Saraiva PP, Benavides F, Nunez-Gomez Y, Solano JP, Opris I, Guest JD, Noga BR. Deep brain stimulation of midbrain locomotor circuits in the freely moving pig. Brain Stimul 2021; 14:467-476. [PMID: 33652130 PMCID: PMC9097921 DOI: 10.1016/j.brs.2021.02.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 01/01/2023] Open
Abstract
Background: Deep brain stimulation (DBS) of the mesencephalic locomotor region (MLR) has been studied as a therapeutic target in rodent models of stroke, parkinsonism, and spinal cord injury. Clinical DBS trials have targeted the closely related pedunculopontine nucleus in patients with Parkinson’s disease as a therapy for gait dysfunction, with mixed reported outcomes. Recent studies suggest that optimizing the MLR target could improve its effectiveness. Objective: We sought to determine if stereotaxic targeting and DBS in the midbrain of the pig, in a region anatomically similar to that previously identified as the MLR in other species, could initiate and modulate ongoing locomotion, as a step towards generating a large animal neuromodulation model of gait. Methods: We implanted Medtronic 3389 electrodes into putative MLR structures in Yucatan micropigs to characterize the locomotor effects of acute DBS in this region, using EMG recordings, joint kinematics, and speed measurements on a manual treadmill. Results: MLR DBS initiated and augmented locomotion in freely moving micropigs. Effective locomotor sites centered around the cuneiform nucleus and stimulation frequency controlled locomotor speed and stepping frequency. Off-target stimulation evoked defensive and aversive behaviors that precluded locomotion in the animals. Conclusion: Pigs appear to have an MLR and can be used to model neuromodulation of this gait-promoting center. These results indicate that the pig is a useful model to guide future clinical studies for optimizing MLR DBS in cases of gait deficiencies associated with such conditions as Parkinson’s disease, spinal cord injury, or stroke.
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Affiliation(s)
- Stephano J Chang
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA; Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Andrea J Santamaria
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Francisco J Sanchez
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Luz M Villamil
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Pedro Pinheiro Saraiva
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Francisco Benavides
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Yohjans Nunez-Gomez
- Department of Pediatric Critical Care, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Juan P Solano
- Department of Pediatric Critical Care, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ioan Opris
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - James D Guest
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Brian R Noga
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.
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40
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Akay T, Murray AJ. Relative Contribution of Proprioceptive and Vestibular Sensory Systems to Locomotion: Opportunities for Discovery in the Age of Molecular Science. Int J Mol Sci 2021; 22:1467. [PMID: 33540567 PMCID: PMC7867206 DOI: 10.3390/ijms22031467] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/20/2021] [Accepted: 01/26/2021] [Indexed: 12/29/2022] Open
Abstract
Locomotion is a fundamental animal behavior required for survival and has been the subject of neuroscience research for centuries. In terrestrial mammals, the rhythmic and coordinated leg movements during locomotion are controlled by a combination of interconnected neurons in the spinal cord, referred as to the central pattern generator, and sensory feedback from the segmental somatosensory system and supraspinal centers such as the vestibular system. How segmental somatosensory and the vestibular systems work in parallel to enable terrestrial mammals to locomote in a natural environment is still relatively obscure. In this review, we first briefly describe what is known about how the two sensory systems control locomotion and use this information to formulate a hypothesis that the weight of the role of segmental feedback is less important at slower speeds but increases at higher speeds, whereas the weight of the role of vestibular system has the opposite relation. The new avenues presented by the latest developments in molecular sciences using the mouse as the model system allow the direct testing of the hypothesis.
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Affiliation(s)
- Turgay Akay
- Atlantic Mobility Action Project, Brain Repair Centre, Department of Medical Neuroscience, Life Science Research Institute, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Andrew J. Murray
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, London W1T 4JG, UK
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Orienting Movements: Brainstem Neurons at the Wheel. Curr Biol 2020; 30:R1418-R1420. [PMID: 33290707 DOI: 10.1016/j.cub.2020.09.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The nervous system must constantly adjust its motor output in response to changes in the environment. A new study of the control of orienting movements in mice has identified discrete groups of neurons in the brainstem that connect a sensory integrative area with distinct features of motor behaviour.
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Hérent C, Diem S, Fortin G, Bouvier J. Absent phasing of respiratory and locomotor rhythms in running mice. eLife 2020; 9:61919. [PMID: 33258770 PMCID: PMC7707822 DOI: 10.7554/elife.61919] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022] Open
Abstract
Examining whether and how the rhythms of limb and breathing movements interact is highly informative about the mechanistic origin of hyperpnoea during running exercise. However, studies have failed to reveal regularities. In particular, whether breathing frequency is inherently proportional to limb velocity and imposed by a synchronization of breaths to strides is still unclear. Here, we examined respiratory changes during running in the resourceful mouse model. We show that, for a wide range of trotting speeds on a treadmill, respiratory rate increases to a fixed and stable value irrespective of trotting velocities. Respiratory rate was yet further increased during escape-like running and most particularly at gallop. However, we found no temporal coordination of breaths to strides at any speed, intensity, or gait. Our work thus highlights that exercise hyperpnoea can operate, at least in mice and in the presently examined running regimes, without phasic constraints from limb movements.
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Affiliation(s)
- Coralie Hérent
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, Gif-sur-Yvette, France
| | - Séverine Diem
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, Gif-sur-Yvette, France
| | - Gilles Fortin
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Julien Bouvier
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, Gif-sur-Yvette, France
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