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Poulen G, Perrin FE. Advances in spinal cord injury: insights from non-human primates. Neural Regen Res 2024; 19:2354-2364. [PMID: 38526271 PMCID: PMC11090432 DOI: 10.4103/nrr.nrr-d-23-01505] [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: 09/06/2023] [Revised: 11/13/2023] [Accepted: 12/22/2023] [Indexed: 03/26/2024] Open
Abstract
Spinal cord injury results in significant sensorimotor deficits, currently, there is no curative treatment for the symptoms induced by spinal cord injury. Basic and pre-clinical research on spinal cord injury relies on the development and characterization of appropriate animal models. These models should replicate the symptoms observed in human, allowing for the exploration of functional deficits and investigation into various aspects of physiopathology of spinal cord injury. Non-human primates, due to their close phylogenetic association with humans, share more neuroanatomical, genetic, and physiological similarities with humans than rodents. Therefore, the responses to spinal cord injury in nonhuman primates most likely resemble the responses to traumatism in humans. In this review, we will discuss nonhuman primate models of spinal cord injury, focusing on in vivo assessments, including behavioral tests, magnetic resonance imaging, and electrical activity recordings, as well as ex vivo histological analyses. Additionally, we will present therapeutic strategies developed in non-human primates and discuss the unique specificities of non-human primate models of spinal cord injury.
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Affiliation(s)
- Gaetan Poulen
- University of Montpellier, INSERM, EPHE, Montpellier, France
- Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, Montpellier, France
| | - Florence E. Perrin
- University of Montpellier, INSERM, EPHE, Montpellier, France
- Institut Universitaire de France (IUF), Paris, France
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2
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Girondini M, Montanaro M, Lega C, Gallace A. Spatial sensorimotor mismatch between the motor command and somatosensory feedback decreases motor cortical excitability. A transcranial magnetic stimulation-virtual reality study. Eur J Neurosci 2024; 60:5348-5361. [PMID: 39171623 DOI: 10.1111/ejn.16481] [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: 02/09/2024] [Revised: 06/25/2024] [Accepted: 07/13/2024] [Indexed: 08/23/2024]
Abstract
Effective control of movement predominantly depends on the exchange and integration between sensory feedback received by our body and motor command. However, the precise mechanisms governing the adaptation of the motor system's response to altered somatosensory signals (i.e., discrepancies between an action performed and feedback received) following movement execution remain largely unclear. In order to address these questions, we developed a unique paradigm using virtual reality (VR) technology. This paradigm can induce spatial incongruence between the motor commands executed by a body district (i.e., moving the right hand) and the resulting somatosensory feedback received (i.e., feeling touch on the left ankle). We measured functional sensorimotor plasticity in 17 participants by assessing the effector's motor cortical excitability (right hand) before and after a 10-min VR task. The results revealed a decrease in motor cortical excitability of the movement effector following exposure to a 10-min conflict between the motor output and the somatosensory input, in comparison to the control condition where spatial congruence between the moved body part and the area of the body that received the feedback was maintained. This finding provides valuable insights into the functional plasticity resulting from spatial sensorimotor conflict arising from the discrepancy between the anticipated and received somatosensory feedback following movement execution. The cortical reorganization observed can be attributed to functional plasticity mechanisms within the sensorimotor cortex that are related to establishing a new connection between somatosensory input and motor output, guided by temporal binding and the Hebbian plasticity rule.
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Affiliation(s)
- Matteo Girondini
- Department of Psychology, University of Milano-Bicocca, Milan, Italy
- Mind and Behavior Technological Center, University of Milano-Bicocca, Milan, Italy
- MySpace Lab, Department of Clinical Neuroscience, University Hospital of Lausanne, Lausanne, Switzerland
| | - Massimo Montanaro
- Mind and Behavior Technological Center, University of Milano-Bicocca, Milan, Italy
| | - Carlotta Lega
- Department of Psychology, University of Milano-Bicocca, Milan, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Alberto Gallace
- Department of Psychology, University of Milano-Bicocca, Milan, Italy
- Mind and Behavior Technological Center, University of Milano-Bicocca, Milan, Italy
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3
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Pellicer-Morata V, Wang L, de Jongh Curry A, Tsao JW, Waters RS. Sources of Rapid and Delayed New Lower Jaw Input in the Forepaw Barrel Subfield (FBS) in Rat Primary Somatosensory Cortex (SI) Following Forelimb Deafferentation. J Comp Neurol 2024; 532:e25664. [PMID: 39235156 PMCID: PMC11506729 DOI: 10.1002/cne.25664] [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: 04/05/2024] [Revised: 07/08/2024] [Accepted: 08/06/2024] [Indexed: 09/06/2024]
Abstract
Previously, we reported an immediate emergence of new lower jaw input to the anterior forepaw barrel subfield (FBS) in primary somatosensory cortex (SI) following forelimb deafferentation. However, a delay of 7 weeks or more post-amputation results in the presence of this new input to both anterior and posterior FBS. The immediate change suggests pre-existing latent lower jaw input in the FBS, whereas the delayed alteration implies the involvement of alternative sources. One possible source for immediate lower jaw responses is the neighboring lower jaw barrel subfield (LJBSF). We used anatomical tracers to investigate the possible projection of LJBSF to the FBS in normal and forelimb-amputated rats. Our findings are as follows: (1) anterograde tracer injection into LJBSF in normal and amputated rats labeled fibers and terminals exclusively in the anterior FBS; (2) retrograde tracer injection in the anterior FBS in normal and forelimb-amputated rats, heavily labeled cell bodies predominantly in the posterior LJBSF, with fewer in the anterior LJBSF; (3) retrograde tracer injection in the posterior FBS in normal and forelimb-amputated rats, sparsely labeled cell bodies in the posterior LJBSF; (4) retrograde tracer injection in anterior and posterior FBS in normal and forelimb-amputated rats, labeled cells exclusively in ventral posterior lateral (VPL) nucleus and posterior thalamus (PO); (5) retrograde tracer injection in LJBSF-labeled cell bodies exclusively in ventral posterior medial thalamic nucleus and PO. These findings suggest that LJBSF facilitates rapid lower jaw reorganization in the anterior FBS, whereas VPL and/or other subcortical sites provide a likely substrate for delayed reorganization observed in the posterior FBS.
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Affiliation(s)
- Violeta Pellicer-Morata
- Department of Physiology, University of Tennessee Health Science Center, College of Medicine, 956 Court Avenue, Memphis, TN 38163, USA
| | - Lie Wang
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Suite, Memphis, TN 38163, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - Jack W. Tsao
- Department of Neurology, New York University, Langone School of Medicine, 550 1 Avenue, New York, NY 10016, USA
| | - Robert S. Waters
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Suite, Memphis, TN 38163, USA
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
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4
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Kubota E, Yan X, Tung S, Fascendini B, Tyagi C, Duhameau S, Ortiz D, Grotheer M, Natu VS, Keil B, Grill-Spector K. White matter connections of human ventral temporal cortex are organized by cytoarchitecture, eccentricity, and category-selectivity from birth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.29.605705. [PMID: 39131283 PMCID: PMC11312531 DOI: 10.1101/2024.07.29.605705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Category-selective regions in ventral temporal cortex (VTC) have a consistent anatomical organization, which is hypothesized to be scaffolded by white matter connections. However, it is unknown how white matter connections are organized from birth. Here, we scanned newborn to 6-month-old infants and adults and used a data-driven approach to determine the organization of the white matter connections of VTC. We find that white matter connections are organized by cytoarchitecture, eccentricity, and category from birth. Connectivity profiles of functional regions in the same cytoarchitectonic area are similar from birth and develop in parallel, with decreases in endpoint connectivity to lateral occipital, and parietal, and somatosensory cortex, and increases to lateral prefrontal cortex. Additionally, connections between VTC and early visual cortex are organized topographically by eccentricity bands and predict eccentricity biases in VTC. These data have important implications for theories of cortical functional development and open new possibilities for understanding typical and atypical white matter development.
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Affiliation(s)
- Emily Kubota
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Xiaoqian Yan
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Sarah Tung
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Bella Fascendini
- Department of Psychology, Princeton University, Peretsmfan Scully Hall, Princeton, NJ 08540, USA
| | - Christina Tyagi
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Sophie Duhameau
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Danya Ortiz
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Mareike Grotheer
- Department of Psychology, Philipps-Universität Marburg, Frankfurter Str. 35, Marburg 35037, Germany
- Center for Mind, Brain and Behavior – CMBB, Universities of Marburg, Giessen, and Darmstadt, Marburg 35039, Germany
| | - Vaidehi S. Natu
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Boris Keil
- Center for Mind, Brain and Behavior – CMBB, Universities of Marburg, Giessen, and Darmstadt, Marburg 35039, Germany
- Institute of Medical Physics and Radiation Protection, TH Mittelhessen University of Applied Sciences, Giessen 35390, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Marburg, Philipps-Universität Marburg, Baldinger Str., Marburg 35043, Germany
- LOEWE Research Cluster for Advanced Medical Physics in Imaging and Therapy (ADMIT), TH Mittelhessen University of Applied Sciences, Giessen 35390, Germany
| | - Kalanit Grill-Spector
- Department of Psychology, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, 288 Campus Drive, Stanford, CA 94305 USA
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Calderone A, Cardile D, De Luca R, Quartarone A, Corallo F, Calabrò RS. Brain Plasticity in Patients with Spinal Cord Injuries: A Systematic Review. Int J Mol Sci 2024; 25:2224. [PMID: 38396902 PMCID: PMC10888628 DOI: 10.3390/ijms25042224] [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: 01/18/2024] [Revised: 02/09/2024] [Accepted: 02/11/2024] [Indexed: 02/25/2024] Open
Abstract
A spinal cord injury (SCI) causes changes in brain structure and brain function due to the direct effects of nerve damage, secondary mechanisms, and long-term effects of the injury, such as paralysis and neuropathic pain (NP). Recovery takes place over weeks to months, which is a time frame well beyond the duration of spinal shock and is the phase in which the spinal cord remains unstimulated below the level of injury and is associated with adaptations occurring throughout the nervous system, often referred to as neuronal plasticity. Such changes occur at different anatomical sites and also at different physiological and molecular biological levels. This review aims to investigate brain plasticity in patients with SCIs and its influence on the rehabilitation process. Studies were identified from an online search of the PubMed, Web of Science, and Scopus databases. Studies published between 2013 and 2023 were selected. This review has been registered on OSF under (n) 9QP45. We found that neuroplasticity can affect the sensory-motor network, and different protocols or rehabilitation interventions can activate this process in different ways. Exercise rehabilitation training in humans with SCIs can elicit white matter plasticity in the form of increased myelin water content. This review has demonstrated that SCI patients may experience plastic changes either spontaneously or as a result of specific neurorehabilitation training, which may lead to positive outcomes in functional recovery. Clinical and experimental evidence convincingly displays that plasticity occurs in the adult CNS through a variety of events following traumatic or non-traumatic SCI. Furthermore, efficacy-based, pharmacological, and genetic approaches, alone or in combination, are increasingly effective in promoting plasticity.
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Affiliation(s)
- Andrea Calderone
- Graduate School of Health Psychology, Department of Clinical and Experimental Medicine, University of Messina, 98122 Messina, Italy;
| | - Davide Cardile
- IRCCS Centro Neurolesi Bonino-Pulejo, S.S. 113 Via Palermo, C.da Casazza, 98124 Messina, Italy
| | - Rosaria De Luca
- IRCCS Centro Neurolesi Bonino-Pulejo, S.S. 113 Via Palermo, C.da Casazza, 98124 Messina, Italy
| | - Angelo Quartarone
- IRCCS Centro Neurolesi Bonino-Pulejo, S.S. 113 Via Palermo, C.da Casazza, 98124 Messina, Italy
| | - Francesco Corallo
- IRCCS Centro Neurolesi Bonino-Pulejo, S.S. 113 Via Palermo, C.da Casazza, 98124 Messina, Italy
| | - Rocco Salvatore Calabrò
- IRCCS Centro Neurolesi Bonino-Pulejo, S.S. 113 Via Palermo, C.da Casazza, 98124 Messina, Italy
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Zhao S, Tang C, Weinberger J, Gao D, Hou S. Sprouting of afferent and efferent inputs to pelvic organs after spinal cord injury. J Neuropathol Exp Neurol 2023; 83:20-29. [PMID: 38102789 PMCID: PMC10746698 DOI: 10.1093/jnen/nlad108] [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: 12/17/2023] Open
Abstract
Neural plasticity occurs within the central and peripheral nervous systems after spinal cord injury (SCI). Although central alterations have extensively been studied, it is largely unknown whether afferent and efferent fibers in pelvic viscera undergo similar morphological changes. Using a rat spinal cord transection model, we conducted immunohistochemistry to investigate afferent and efferent innervations to the kidney, colon, and bladder. Approximately 3-4 weeks after injury, immunostaining demonstrated that tyrosine hydroxylase (TH)-labeled postganglionic sympathetic fibers and calcitonin gene-related peptide (CGRP)-immunoreactive sensory terminals sprout in the renal pelvis and colon. Morphologically, sprouted afferent or efferent projections showed a disorganized structure. In the bladder, however, denser CGRP-positive primary sensory fibers emerged in rats with SCI, whereas TH-positive sympathetic efferent fibers did not change. Numerous CGRP-positive afferents were observed in the muscle layer and the lamina propria of the bladder following SCI. TH-positive efferent inputs displayed hypertrophy with large diameters, but their innervation patterns were sustained. Collectively, afferent or efferent inputs sprout widely in the pelvic organs after SCI, which may be one of the morphological bases underlying functional adaptation or maladaptation.
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Affiliation(s)
- Shunyi Zhao
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, USA
- Department of Pharmacology and Physiology, Drexel University College of Medicine, USA
| | - Chuanxi Tang
- Department of Neurobiology and Cell Biology, Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jeremy Weinberger
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, USA
| | - Dianshuai Gao
- Department of Neurobiology and Cell Biology, Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Shaoping Hou
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, USA
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Pellicer-Morata V, Wang L, Curry ADJ, Tsao JW, Waters RS. Lower jaw-to-forepaw rapid and delayed reorganization in the rat forepaw barrel subfield in primary somatosensory cortex. J Comp Neurol 2023; 531:1651-1668. [PMID: 37496376 PMCID: PMC10530121 DOI: 10.1002/cne.25523] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/24/2023] [Accepted: 06/26/2023] [Indexed: 07/28/2023]
Abstract
We used the forepaw barrel subfield (FBS), that normally receives input from the forepaw skin surface, in rat primary somatosensory cortex as a model system to study rapid and delayed lower jaw-to-forepaw cortical reorganization. Single and multi-unit recording from FBS neurons was used to examine the FBS for the presence of "new" lower jaw input following deafferentations that include forelimb amputation, brachial plexus nerve cut, and brachial plexus anesthesia. The major findings are as follows: (1) immediately following forelimb deafferentations, new input from the lower jaw becomes expressed in the anterior FBS; (2) 7-27 weeks after forelimb amputation, new input from the lower jaw is expressed in both anterior and posterior FBS; (3) evoked response latencies recorded in the deafferented FBS following electrical stimulation of the lower jaw skin surface are significantly longer in both rapid and delayed deafferents compared to control latencies for input from the forepaw to reach the FBS or for input from lower jaw to reach the LJBSF; (4) the longer latencies suggest that an additional relay site is imposed along the somatosensory pathway for lower jaw input to access the deafferented FBS. We conclude that different sources of input and different mechanisms underlie rapid and delayed reorganization in the FBS and suggest that these findings are relevant, as an initial step, for developing a rodent animal model to investigate phantom limb phenomena.
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Affiliation(s)
- Violeta Pellicer-Morata
- Department of Physiology, University of Tennessee Health
Science Center, College of Medicine, 956 Court Avenue, Memphis, TN 38163, USA
| | - Lie Wang
- Department of Anatomy and Neurobiology, University of
Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Suite,
Memphis, TN 38163, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of
Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152,
USA
| | - Jack W. Tsao
- Department of Neurology, New York University, Langone
School of Medicine, 550 1 Avenue, New York, NY 10016, USA
| | - Robert S. Waters
- Department of Anatomy and Neurobiology, University of
Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Suite,
Memphis, TN 38163, USA
- Department of Biomedical Engineering, University of
Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152,
USA
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Alonso-Calviño E, Fernández-López E, Zaforas M, Rosa JM, Aguilar J. Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury. Exp Neurol 2023; 369:114504. [PMID: 37591355 DOI: 10.1016/j.expneurol.2023.114504] [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: 04/29/2023] [Revised: 07/07/2023] [Accepted: 08/11/2023] [Indexed: 08/19/2023]
Abstract
The complete or partial damage of ascending somatosensory pathways produced by a spinal cord injury triggers changes in the somatosensory cortex consisting in a functional expansion of activity from intact cortical regions towards deafferented ones, a process known as cortical reorganization. However, it is still unclear whether cortical reorganization depends on the severity of the spinal cord damage or if a spinal cord injury always leads to a similar cortical reorganization process in the somatosensory cortex. To answer these open questions in the field, we obtained longitudinal somatosensory evoked responses from bilateral hindlimb and forelimb cortex from animals with chronic full-transection or contusive spinal cord injury at thoracic level (T9-T10) to induce sensory deprivation of hindlimb cortex while preserving intact the forelimb cortex. Electrophysiological recordings from the four locations were obtained before lesion and weekly for up to 4 weeks. Our results show that cortical reorganization depends on the type of spinal cord injury, which tends to be more bilateral in full transection while is more unilateral in the model of contusive spinal cord injury. Moreover, in full transection of spinal cord, the deafferented and intact cortex exhibited similar increments of somatosensory evoked responses in both models of spinal cord injury - a feature observed in about 80% of subjects. The other 20% were unaffected by the injury indicating that cortical reorganization does not undergo in all subjects. In addition, we demonstrated an increased probability of triggered up-states in animals with spinal cord injury. This data indicates increased cortical excitability that could be proposed as a new feature of cortical reorganization. Finally, decreased levels of GABA marker GAD67 across cortical layers were only found in those animals with increased somatosensory evoked responses, but not in the unaffected population. In conclusion, cortical reorganization depends on the types of spinal cord injuries, and suggest that the phenomenon is strongly determined by cortical circuits. Moreover, changes in GABAergic transmission at the deprived cortex may be considered one of the mechanisms underlying the process of cortical reorganization and increased excitability.
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Affiliation(s)
- Elena Alonso-Calviño
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain
| | - Elena Fernández-López
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain
| | - Marta Zaforas
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain
| | - Juliana M Rosa
- Neuronal Circuits and Behaviour Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain
| | - Juan Aguilar
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain.
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Ueta Y, Miyata M. Functional and structural synaptic remodeling mechanisms underlying somatotopic organization and reorganization in the thalamus. Neurosci Biobehav Rev 2023; 152:105332. [PMID: 37524138 DOI: 10.1016/j.neubiorev.2023.105332] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/09/2023] [Accepted: 07/27/2023] [Indexed: 08/02/2023]
Abstract
The somatosensory system organizes the topographic representation of body maps, termed somatotopy, at all levels of an ascending hierarchy. Postnatal maturation of somatotopy establishes optimal somatosensation, whereas deafferentation in adults reorganizes somatotopy, which underlies pathological somatosensation, such as phantom pain and complex regional pain syndrome. Here, we focus on the mouse whisker somatosensory thalamus to study how sensory experience shapes the fine topography of afferent connectivity during the critical period and what mechanisms remodel it and drive a large-scale somatotopic reorganization after peripheral nerve injury. We will review our findings that, following peripheral nerve injury in adults, lemniscal afferent synapses onto thalamic neurons are remodeled back to immature configuration, as if the critical period reopens. The remodeling process is initiated with local activation of microglia in the brainstem somatosensory nucleus downstream to injured nerves and heterosynaptically controlled by input from GABAergic and cortical neurons to thalamic neurons. These fruits of thalamic studies complement well-studied cortical mechanisms of somatotopic organization and reorganization and unveil potential intervention points in treating pathological somatosensation.
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Affiliation(s)
- Yoshifumi Ueta
- Division of Neurophysiology, Department of Physiology, School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Mariko Miyata
- Division of Neurophysiology, Department of Physiology, School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan.
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10
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Datta A. The effect of dorsal column lesions in the primary somatosensory cortex and medulla of adult rats. IBRO Neurosci Rep 2023; 14:466-482. [PMID: 37273897 PMCID: PMC10238474 DOI: 10.1016/j.ibneur.2023.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/12/2023] [Indexed: 06/06/2023] Open
Abstract
Spinal cord injury is a devastating condition that haunts human lives. Typically, patients experience referred phantom sensations on the hand when they are touched on the face. In adult monkeys, massive deafferentations such as chronic dorsal column lesions at higher cervical levels result in the large-scale expansion of face inputs into the deafferented hand cortex of area 3b. However, adult rats with thoracic dorsal column lesions do not demonstrate such large-scale reorganization. The large-scale face expansion in area 3b of monkeys is driven by the reorganization of the cuneate nucleus in the medulla. The sprouting of afferents from the trigeminal nucleus to the adjacent deafferented cuneate nucleus is facilitated by close proximity and compactness of the medulla in primates. Previously, in adult rats with thoracic lesions, the cuneate nucleus was not deafferented and its functional organization was not explored. The extent of the deafferentation and the duration of the recovery period are two major factors that determine the extent of reorganization. Hence, higher cervical (C3-C4) dorsal column lesions were performed, which cause massive deafferentations, and physiological maps were obtained after prolonged recovery periods (3 weeks -18 months). In spite of the above, the expansion of the intact face inputs was not observed in the deafferented zones of the primary somatosensory cortex (SI) and medulla of adult rats. The deafferented forelimb and hindlimb representations in SI were unresponsive to cutaneous stimulation of any part of the body. The cuneate and gracile nuclei in rats with complete dorsal column lesions remained mostly inactive except for a few sites which responded to stimulation of the spared upper arm. Hence, dorsal column lesions have different effects on the adult primate and rodent somatosensory systems. Appreciating this inter-species difference can aid in identifying the underlying neural substrates and restrict maladaptive reorganizations to cure phantom sensations.
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Qi HX, Reed JL, Liao CC, Kaas JH. Regressive changes in sizes of somatosensory cuneate nucleus after sensory loss in primates. Proc Natl Acad Sci U S A 2023; 120:e2222076120. [PMID: 36877853 PMCID: PMC10242712 DOI: 10.1073/pnas.2222076120] [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: 01/04/2023] [Accepted: 02/06/2023] [Indexed: 03/08/2023] Open
Abstract
Neurons in the early stages of processing sensory information suffer transneuronal atrophy when deprived of their activating inputs. For over 40 y, members of our laboratory have studied the reorganization of the somatosensory cortex during and after recovering from different types of sensory loss. Here, we took advantage of the preserved histological material from these studies of the cortical effects of sensory loss to evaluate the histological consequences in the cuneate nucleus of the lower brainstem and the adjoining spinal cord. The neurons in the cuneate nucleus are activated by touch on the hand and arm, and relay this activation to the contralateral thalamus, and from the thalamus to the primary somatosensory cortex. Neurons deprived of activating inputs tend to shrink and sometimes die. We considered the effects of differences in species, type and extent of sensory loss, recovery time after injury, and age at the time of injury on the histology of the cuneate nucleus. The results indicate that all injuries that deprived part or all of the cuneate nucleus of sensory activation result in some atrophy of neurons as reflected by a decrease in nucleus size. The extent of the atrophy is greater with greater sensory loss and with longer recovery times. Based on supporting research, atrophy appears to involve a reduction in neuron size and neuropil, with little or no neuron loss. Thus, the potential exists for restoring the hand to cortex pathway with brain-machine interfaces, for bionic prosthetics, or biologically with hand replacement surgery.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN37240
| | - Jamie L. Reed
- Department of Psychology, Vanderbilt University, Nashville, TN37240
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN37240
| | - Jon H. Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN37240
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Beisheim-Ryan EH, Pohlig RT, Hicks GE, Horne JR, Sions JM. Post-amputation pain: Comparing pain presentations between adults with and without increased amputated-region sensitivity. Pain Pract 2023; 23:155-166. [PMID: 36250812 PMCID: PMC9905279 DOI: 10.1111/papr.13172] [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: 12/13/2021] [Revised: 09/27/2022] [Accepted: 10/11/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Among adults with persistent post-amputation pain, increased amputated-region pain sensitivity may reflect peripheral sensitization or indicate underlying central sensitization. To determine whether underlying central sensitization may contribute to increased pain sensitivity in this population, this study compared clinical signs and symptoms associated with central sensitization between adults with post-amputation pain who demonstrate or lack increased amputated-region sensitivity (as compared to reference data). DESIGN Cross-sectional. SUBJECTS Ninety-nine adults (60 with a unilateral, transtibial amputation and post-amputation pain, 39 pain-free controls with intact limbs). METHODS Participants underwent pain-pressure threshold testing of amputated-region and secondary (non-amputated region) sites and completed outcome measures assessing central sensitization symptoms (Patient-Reported Outcomes Measurement Information System® pain intensity and interference domains, Central Sensitization Inventory). Among the full sample, the presence and frequency of specific central sensitization symptoms were evaluated. Participants with post-amputation pain were then grouped based on whether normalized, amputated-region pain-pressure thresholds fell below (i.e., sensitive) or above (i.e., non-sensitive) the 25th percentile of sex-specific reference data. Between-group differences in normalized secondary-site sensitivity were evaluated using a multivariate analysis of variance; central sensitization symptom scores were compared using a Kruskal-Wallis test. RESULTS Noteworthy symptoms associated with central sensitization (e.g., fatigue, sleep disturbance, cognitive difficulty) were reported by 33%-62% of participants. Secondary-site pain sensitivity was greater among individuals with increased amputated-region sensitivity (n = 24) compared to peers without increased amputated-region sensitivity ([n = 36], mean difference > 1.33 standard deviation [SD], p < 0.001). Central sensitization symptom scores, however, were similar between groups (p > 0.187). CONCLUSIONS Participants with increased amputated-region sensitivity demonstrate generalized, secondary-site pain hypersensitivity, potentially indicating underlying central sensitization. Central sensitization symptom scores, however, were similar between groups, suggesting differences in physiological pain sensitivity may not manifest in subjective post-amputation pain descriptions.
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Affiliation(s)
- Emma Haldane Beisheim-Ryan
- University of Delaware Department of Physical Therapy, 540 South College Avenue, Newark, DE, 19713, USA
- VA Eastern Colorado Geriatric Research, Education, and Clinical Center (GRECC), VA Eastern Colorado Health Care System, 1700 N Wheeling Street, Aurora, CO, 80045, USA
| | - Ryan Todd Pohlig
- University of Delaware Biostatistics Core, 102B STAR Tower, Newark, DE, 19713, USA
| | - Gregory Evan Hicks
- University of Delaware Department of Physical Therapy, 540 South College Avenue, Newark, DE, 19713, USA
| | - John Robert Horne
- Independence Prosthetics-Orthotics, Inc., 550 South College Avenue, Suite 111, Newark, DE, 19713, USA
| | - Jaclyn Megan Sions
- University of Delaware Department of Physical Therapy, 540 South College Avenue, Newark, DE, 19713, USA
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Liu S, Fu W, Wei C, Ma F, Cui N, Shan X, Zhang Y. Interference of unilateral lower limb amputation on motor imagery rhythm and remodeling of sensorimotor areas. Front Hum Neurosci 2022; 16:1011463. [DOI: 10.3389/fnhum.2022.1011463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/19/2022] [Indexed: 11/05/2022] Open
Abstract
PurposeThe effect of sensorimotor stripping on neuroplasticity and motor imagery capacity is unknown, and the physiological mechanisms of post-amputation phantom limb pain (PLP) illness remain to be investigated.Materials and methodsIn this study, an electroencephalogram (EEG)-based event-related (de)synchronization (ERD/ERS) analysis was conducted using a bilateral lower limb motor imagery (MI) paradigm. The differences in the execution of motor imagery tasks between left lower limb amputations and healthy controls were explored, and a correlation analysis was calculated between level of phantom limb pain and ERD/ERS.ResultsThe multiple frequency bands showed a significant ERD phenomenon when the healthy control group performed the motor imagery task, whereas amputees showed significant ERS phenomena in mu band. Phantom limb pain in amputees was negatively correlated with bilateral sensorimotor areas electrode powers.ConclusionSensorimotor abnormalities reduce neural activity in the sensorimotor cortex, while the motor imagination of the intact limb is diminished. In addition, phantom limb pain may lead to over-activation of sensorimotor areas, affecting bilateral sensorimotor area remodeling.
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Plasticity of the Central Nervous System Involving Peripheral Nerve Transfer. Neural Plast 2022; 2022:5345269. [PMID: 35342394 PMCID: PMC8956439 DOI: 10.1155/2022/5345269] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/09/2022] [Accepted: 02/28/2022] [Indexed: 11/22/2022] Open
Abstract
Peripheral nerve injury can lead to partial or complete loss of limb function, and nerve transfer is an effective surgical salvage for patients with these injuries. The inability of deprived cortical regions representing damaged nerves to overcome corresponding maladaptive plasticity after the reinnervation of muscle fibers and sensory receptors is thought to be correlated with lasting and unfavorable functional recovery. However, the concept of central nervous system plasticity is rarely elucidated in classical textbooks involving peripheral nerve injury, let alone peripheral nerve transfer. This article is aimed at providing a comprehensive understanding of central nervous system plasticity involving peripheral nerve injury by reviewing studies mainly in human or nonhuman primate and by highlighting the functional and structural modifications in the central nervous system after peripheral nerve transfer. Hopefully, it will help surgeons perform successful nerve transfer under the guidance of modern concepts in neuroplasticity.
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Leemhuis E, Giuffrida V, De Martino ML, Forte G, Pecchinenda A, De Gennaro L, Giannini AM, Pazzaglia M. Rethinking the Body in the Brain after Spinal Cord Injury. J Clin Med 2022; 11:jcm11020388. [PMID: 35054089 PMCID: PMC8780443 DOI: 10.3390/jcm11020388] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 01/12/2022] [Indexed: 02/05/2023] Open
Abstract
Spinal cord injuries (SCI) are disruptive neurological events that severly affect the body leading to the interruption of sensorimotor and autonomic pathways. Recent research highlighted SCI-related alterations extend beyond than the expected network, involving most of the central nervous system and goes far beyond primary sensorimotor cortices. The present perspective offers an alternative, useful way to interpret conflicting findings by focusing on the deafferented and deefferented body as the central object of interest. After an introduction to the main processes involved in reorganization according to SCI, we will focus separately on the body regions of the head, upper limbs, and lower limbs in complete, incomplete, and deafferent SCI participants. On one hand, the imprinting of the body’s spatial organization is entrenched in the brain such that its representation likely lasts for the entire lifetime of patients, independent of the severity of the SCI. However, neural activity is extremely adaptable, even over short time scales, and is modulated by changing conditions or different compensative strategies. Therefore, a better understanding of both aspects is an invaluable clinical resource for rehabilitation and the successful use of modern robotic technologies.
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Affiliation(s)
- Erik Leemhuis
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Valentina Giuffrida
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Maria Luisa De Martino
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Giuseppe Forte
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Correspondence: (G.F.); (M.P.); Tel.: +39-6-49917633 (M.P.)
| | - Anna Pecchinenda
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
| | - Luigi De Gennaro
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Anna Maria Giannini
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
| | - Mariella Pazzaglia
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy; (E.L.); (V.G.); (M.L.D.M.); (A.P.); (L.D.G.); (A.M.G.)
- Action and Body Lab, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Correspondence: (G.F.); (M.P.); Tel.: +39-6-49917633 (M.P.)
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Behavioral recovery after a spinal deafferentation injury in monkeys does not correlate with extent of corticospinal sprouting. Behav Brain Res 2022; 416:113533. [PMID: 34453971 PMCID: PMC8492525 DOI: 10.1016/j.bbr.2021.113533] [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: 05/19/2021] [Revised: 07/26/2021] [Accepted: 08/13/2021] [Indexed: 01/09/2023]
Abstract
A long held view in the spinal cord injury field is that corticospinal terminal sprouting is needed for new connections to form, that then mediate behavioral recovery. This makes sense, but tells us little about the relationship between corticospinal sprouting extent and recovery potential. The inference has been that more extensive axonal sprouting predicts greater recovery, though there is little evidence to support this. Here we addressed this by comparing behavioral data from monkeys that had received one of two established deafferentation spinal injury models in monkeys (Darian-Smith et al., 2014, Fisher et al., 2019, 2020). Both injuries cut similar afferent pools supplying the thumb, index and middle fingers of one hand but each resulted in a very different corticospinal tract (CST) sprouting response. Following a cervical dorsal root lesion, the somatosensory CST retracted significantly, while the motor CST stayed largely intact. In contrast, when a dorsal column lesion was combined with the DRL, somatosensory and motor CSTs sprouted dramatically within the cervical cord. How these two responses relate to the behavioral outcome was not clear. Here we analyzed the behavioral outcome for the two lesions, and provide a clear example that sprouting extent does not track with behavioral recovery.
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Liao C, Qi H, Reed JL, Jeoung H, Kaas JH. Corticocuneate projections are altered after spinal cord dorsal column lesions in New World monkeys. J Comp Neurol 2021; 529:1669-1702. [PMID: 33029803 PMCID: PMC7987845 DOI: 10.1002/cne.25050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 12/31/2022]
Abstract
Recovery of responses to cutaneous stimuli in the area 3b hand cortex of monkeys after dorsal column lesions (DCLs) in the cervical spinal cord relies on neural rewiring in the cuneate nucleus (Cu) over time. To examine whether the corticocuneate projections are modified during recoveries after the DCL, we injected cholera toxin subunit B into the hand representation in Cu to label the cortical neurons after various recovery times, and related results to the recovery of neural responses in the affected area 3b hand cortex. In normal New World monkeys, labeled neurons were predominately distributed in the hand regions of contralateral areas 3b, 3a, 1 and 2, parietal ventral (PV), secondary somatosensory cortex (S2), and primary motor cortex (M1), with similar distributions in the ipsilateral cortex in significantly smaller numbers. In monkeys with short-term recoveries, the area 3b hand neurons were unresponsive or responded weakly to touch on the hand, while the cortical labeling pattern was largely unchanged. After longer recoveries, the area 3b hand neurons remained unresponsive, or responded to touch on the hand or somatotopically abnormal parts, depending on the lesion extent. The distributions of cortical labeled neurons were much more widespread than the normal pattern in both hemispheres, especially when lesions were incomplete. The proportion of labeled neurons in the contralateral area 3b hand cortex was not correlated with the functional reactivation in the area 3b hand cortex. Overall, our findings indicated that corticocuneate inputs increase during the functional recovery, but their functional role is uncertain.
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Affiliation(s)
- Chia‐Chi Liao
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Hui‐Xin Qi
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Jamie L. Reed
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Ha‐Seul Jeoung
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Jon H. Kaas
- Department of Psychology Vanderbilt University Nashville Tennessee USA
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18
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Qi HX, Liao CC, Reed JL, Kaas JH. Reorganization of Higher-Order Somatosensory Cortex After Sensory Loss from Hand in Squirrel Monkeys. Cereb Cortex 2020; 29:4347-4365. [PMID: 30590401 DOI: 10.1093/cercor/bhy317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/18/2018] [Accepted: 11/20/2018] [Indexed: 12/31/2022] Open
Abstract
Unilateral dorsal column lesions (DCL) at the cervical spinal cord deprive the hand regions of somatosensory cortex of tactile activation. However, considerable cortical reactivation occurs over weeks to months of recovery. While most studies focused on the reactivation of primary somatosensory area 3b, here, for the first time, we address how the higher-order somatosensory cortex reactivates in the same monkeys after DCL that vary across cases in completeness, post-lesion recovery times, and types of treatments. We recorded neural responses to tactile stimulation in areas 3a, 3b, 1, secondary somatosensory cortex (S2), parietal ventral (PV), and occasionally areas 2/5. Our analysis emphasized comparisons of the responsiveness, somatotopy, and receptive field size between areas 3b, 1, and S2/PV across DCL conditions and recovery times. The results indicate that the extents of the reactivation in higher-order somatosensory areas 1 and S2/PV closely reflect the reactivation in primary somatosensory cortex. Responses in higher-order areas S2 and PV can be stronger than those in area 3b, thus suggesting converging or alternative sources of inputs. The results also provide evidence that both primary and higher-order fields are effectively activated after long recovery times as well as after behavioral and electrocutaneous stimulation interventions.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
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Park E, Cha H, Kim E, Min YS, Kim AR, Lee HJ, Jung TD, Chang Y. Alterations in power spectral density in motor- and pain-related networks on neuropathic pain after spinal cord injury. Neuroimage Clin 2020; 28:102342. [PMID: 32798908 PMCID: PMC7453139 DOI: 10.1016/j.nicl.2020.102342] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND The mechanisms by which mobility function and neuropathic pain are mutually influenced by supraspinal plasticity in motor- and pain-related brain networks following spinal cord injury (SCI) remains poorly understood. OBJECTIVE To determine cortical and subcortical resting-state network alterations using power spectral density (PSD) analysis and investigate the relationships between these intrinsic alterations and mobility function and neuropathic pain following SCI. METHODS A total of 41 patients with incomplete SCI and 33 healthy controls were included. The degree of mobility and balance function and severity of neuropathic pain and depressive mood were evaluated. The resting-state functional magnetic resonance imaging data of low-frequency fluctuations were analyzed based on PSD. Differences in PSD values between patients with SCI and controls were assessed using the two-sample t-test (false discovery rate-corrected P < 0.05). The relationship between PSD values and mobility function and pain intensity was assessed using Pearson's correlation coefficient adjusted for the severity of depressive mood. RESULTS Compared with healthy controls, lower PSD values in supplementary motor and medial prefrontal areas (the anterior cingulate cortex, ventral medial prefrontal cortex, and superior orbito-prefrontal cortex) were associated with greater pain severity and poorer postural balance and mobility (P < 0.05) in patients with SCI, whereas higher PSD values in the primary motor cortex, premotor cortex, thalamus, and periaqueductal gray were associated with greater pain severity and poorer postural balance and mobility (P < 0.05). CONCLUSIONS Cortical and subcortical plastic alterations in intrinsic motor- and pain-related networks were observed in patients with SCI and were simultaneously associated with neuropathic pain intensity and degree of mobility function.
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Affiliation(s)
- Eunhee Park
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu, 41944, Korea
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Hyunsil Cha
- Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Korea
| | - Eunji Kim
- Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Korea
| | - Yu-Sun Min
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu, 41944, Korea
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Ae Ryoung Kim
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu, 41944, Korea
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Hui Joong Lee
- Department of Radiology, School of Medicine, Kyungpook National University, Daegu, Korea
- Department of Radiology, Kyungpook National University Hospital, Daegu, Korea
| | - Tae-Du Jung
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu, 41944, Korea
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Yongmin Chang
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu, 41944, Korea
- Department of Radiology, Kyungpook National University Hospital, Daegu, Korea
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu, Korea
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Melo MC, Macedo DR, Soares AB. Divergent Findings in Brain Reorganization After Spinal Cord Injury: A Review. J Neuroimaging 2020; 30:410-427. [PMID: 32418286 DOI: 10.1111/jon.12711] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/02/2020] [Accepted: 03/24/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) leads to a general lack of sensory and motor functions below the level of injury and may promote deafferentation-induced brain reorganization. Functional magnetic resonance imaging (fMRI) has been established as an essential tool in neuroscience research and can precisely map the spatiotemporal distribution of brain activity. Task-based fMRI experiments associated with the tongue, upper limbs, or lower limbs have been used as the primary paradigms to study brain reorganization following SCI. A review of the current literature on the subject shows one common trait: while most articles agree that brain networks are usually preserved after SCI, and that is not the case as some articles describe possible alterations in brain activation after the lesion. There is no consensus if those alterations indeed occur. In articles that show alterations, there is no agreement if they are transient or permanent. Besides, there is no consensus on which areas are most prone to activation changes, or on the intensity and direction (increase vs. decrease) of those possible changes. In this article, we present a critical review of the literature and trace possible reasons for those contradictory findings on brain reorganization following SCI. fMRI studies based on the ankle dorsiflexion, upper-limb, and tongue paradigms are used as case studies for the analyses.
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Affiliation(s)
- Mariana Cardoso Melo
- Biomedical Engineering Lab, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Dhainner Rocha Macedo
- Biomedical Engineering Lab, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Alcimar Barbosa Soares
- Biomedical Engineering Lab, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
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Regional Hyperexcitability and Chronic Neuropathic Pain Following Spinal Cord Injury. Cell Mol Neurobiol 2020; 40:861-878. [PMID: 31955281 DOI: 10.1007/s10571-020-00785-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 01/02/2020] [Indexed: 12/15/2022]
Abstract
Spinal cord injury (SCI) causes maladaptive changes to nociceptive synaptic circuits within the injured spinal cord. Changes also occur at remote regions including the brain stem, limbic system, cortex, and dorsal root ganglia. These maladaptive nociceptive synaptic circuits frequently cause neuronal hyperexcitability in the entire nervous system and enhance nociceptive transmission, resulting in chronic central neuropathic pain following SCI. The underlying mechanism of chronic neuropathic pain depends on the neuroanatomical structures and electrochemical communication between pre- and postsynaptic neuronal membranes, and propagation of synaptic transmission in the ascending pain pathways. In the nervous system, neurons are the only cell type that transmits nociceptive signals from peripheral receptors to supraspinal systems due to their neuroanatomical and electrophysiological properties. However, the entire range of nociceptive signaling is not mediated by any single neuron. Current literature describes regional studies of electrophysiological or neurochemical mechanisms for enhanced nociceptive transmission post-SCI, but few studies report the electrophysiological, neurochemical, and neuroanatomical changes across the entire nervous system following a regional SCI. We, along with others, have continuously described the enhanced nociceptive transmission in the spinal dorsal horn, brain stem, thalamus, and cortex in SCI-induced chronic central neuropathic pain condition, respectively. Thus, this review summarizes the current understanding of SCI-induced neuronal hyperexcitability and maladaptive nociceptive transmission in the entire nervous system that contributes to chronic central neuropathic pain.
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Halder P, Kambi N, Chand P, Jain N. Altered Expression of Reorganized Inputs as They Ascend From the Cuneate Nucleus to Cortical Area 3b in Monkeys With Long-Term Spinal Cord Injuries. Cereb Cortex 2019; 28:3922-3938. [PMID: 29045569 DOI: 10.1093/cercor/bhx256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/12/2017] [Indexed: 01/03/2023] Open
Abstract
Chronic deafferentations in adult mammals result in reorganization of the brain. Lesions of the dorsal columns of the spinal cord at cervical levels in monkeys result in expansion of the intact chin inputs into the deafferented hand representation in area 3b, second somatosensory (S2) and parietal ventral (PV) areas of the somatosensory cortex, ventroposterior lateral nucleus (VPL) of the thalamus, and cuneate nucleus of the brainstem. Here, we describe the extent and nature of reorganization of the cuneate and gracile nuclei of adult macaque monkeys with chronic unilateral lesions of the dorsal columns, and compare it with the reorganization of area 3b in the same monkeys. In both, area 3b and the cuneate nucleus chin inputs expand to reactivate the deafferented neurons. However, unlike area 3b, neurons in the cuneate nucleus also acquire receptive fields on the shoulder, neck, and occiput. A comparison with the previously published results shows that reorganization in the cuneate nucleus is similar to that in VPL. Thus, the emergent topography following deafferentations by spinal cord injuries undergoes transformation as the reorganized inputs ascend from subcortical nuclei to area 3b. The results help us understand mechanisms of the brain plasticity following spinal cord injuries.
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Affiliation(s)
| | - Niranjan Kambi
- National Brain Research Centre, N.H. 8, Manesar, Haryana, India
| | - Prem Chand
- National Brain Research Centre, N.H. 8, Manesar, Haryana, India
| | - Neeraj Jain
- National Brain Research Centre, N.H. 8, Manesar, Haryana, India
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Remapping in Cerebral and Cerebellar Cortices Is Not Restricted by Somatotopy. J Neurosci 2019; 39:9328-9342. [PMID: 31611305 PMCID: PMC6867820 DOI: 10.1523/jneurosci.2599-18.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 07/16/2019] [Accepted: 08/05/2019] [Indexed: 12/27/2022] Open
Abstract
A fundamental organizing principle in the somatosensory and motor systems is somatotopy, where specific body parts are represented separately and adjacently to other body parts, resulting in a body map. Different terminals of the sensorimotor network show varied somatotopic layouts, in which the relative position, distance, and overlap between body-part representations differ. Since somatotopy is best characterized in the primary somatosensory (S1) and motor (M1) cortices, these terminals have been the main focus of research on somatotopic remapping following loss of sensory input (e.g., arm amputation). Cortical remapping is generally considered to be driven by the layout of the underlying somatotopy, such that neighboring body-part representations tend to activate the deprived brain region. Here, we challenge the assumption that somatotopic layout restricts remapping, by comparing patterns of remapping in humans born without one hand (hereafter, one-handers, n = 26) across multiple terminals of the sensorimotor pathway. We first report that, in the cerebellum of one-handers, the deprived hand region represents multiple body parts. Importantly, the native representations of some of these body parts do not neighbor the deprived hand region. We further replicate our previous findings, showing a similar pattern of remapping in the deprived hand region of the cerebral cortex in one-handers. Finally, we report preliminary results of a similar remapping pattern in the putamen of one-handers. Since these three sensorimotor terminals (cerebellum, cerebrum, putamen) contain different somatotopic layouts, the parallel remapping they undergo demonstrates that the mere spatial layout of body-part representations may not exclusively dictate remapping in the sensorimotor systems. SIGNIFICANCE STATEMENT When a hand is missing, the brain region that typically processes information from that hand may instead process information from other body parts, a phenomenon termed remapping. It is commonly thought that only body parts whose information is processed in regions neighboring the hand region could “take up” the resources of this now deprived region. Here we demonstrate that information from multiple body parts is processed in the hand regions of both the cerebral cortex and cerebellum. The native brain regions of these body parts have varying levels of overlap with the hand regions of the cerebral cortex and cerebellum, and do not necessarily neighbor the hand regions. We therefore propose that proximity between brain regions does not limit brain remapping.
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Crowley M, Lilak A, Ahloy-Dallaire J, Darian-Smith C. Spinal cord injury transiently alters Meissner's corpuscle density in the digit pads of macaque monkeys. J Comp Neurol 2019; 527:1901-1912. [PMID: 30707439 DOI: 10.1002/cne.24655] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/14/2019] [Accepted: 01/28/2019] [Indexed: 02/04/2023]
Abstract
Meissner's corpuscles (MCs) are cutaneous mechanoreceptors found in glabrous skin and are exquisitely sensitive to light touch. Along with other receptors, they provide continuous sensory feedback that informs the execution of fine manual behaviors. Following cervical spinal deafferentation injuries, hand use can be initially severely impaired, but substantial recovery occurs over many weeks, even when ~95% of the original input is permanently lost. While most SCI research focuses on central neural pathway responses, little is known about the role of peripheral receptors in facilitating recovery. We begin to address this by asking the following: (1) What is the normal pattern of MCs in the distal pads of all five digits in the macaque monkey (with hands similar to humans)? (2) What happens to these receptors 4-5 months following either a dorsal column lesion (DCL) or a combined dorsal root/dorsal column lesion (DRL/DCL), when functional recovery is largely complete? (3) What happens chronically, 12-14 months later? Our findings show that in normal monkeys, MCs are densest in the distal pads of the opposing thumb and index finger, with the greatest concentration on the thumb. This reflects a close functional relationship between receptor density and precision grip. At 4-5 months post-injury, there was a (~30%) loss of MCs on the deafferented digits of the injured hand compared with the contralateral side. However, 12-14 months after a DRL/DCL, receptor densities had returned to normal levels. Our findings indicate a complex peripheral response and highlight the importance of the periphery in shaping central changes.
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Affiliation(s)
- Matthew Crowley
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
| | - Alayna Lilak
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
| | - Jamie Ahloy-Dallaire
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California.,Département des sciences animales, Université Laval, Québec, Quebec, Canada
| | - Corinna Darian-Smith
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
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The Homuncular Jigsaw: Investigations of Phantom Limb and Body Awareness Following Brachial Plexus Block or Avulsion. J Clin Med 2019; 8:jcm8020182. [PMID: 30717476 PMCID: PMC6406464 DOI: 10.3390/jcm8020182] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 01/29/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Many neuropsychological theories agree that the brain maintains a relatively persistent representation of one’s own body, as indicated by vivid “phantom” experiences. It remains unclear how the loss of sensory and motor information contributes to the presence of this representation. Here, we focus on new empirical and theoretical evidence of phantom sensations following damage to or an anesthetic block of the brachial plexus. We suggest a crucial role of this structure in understanding the interaction between peripheral and central mechanisms in health and in pathology. Studies of brachial plexus function have shed new light on how neuroplasticity enables “somatotopic interferences”, including pain and body awareness. Understanding the relations among clinical disorders, their neural substrate, and behavioral outcomes may enhance methods of sensory rehabilitation for phantom limbs.
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What is the functional relevance of reorganization in primary motor cortex after spinal cord injury? Neurobiol Dis 2019; 121:286-295. [DOI: 10.1016/j.nbd.2018.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 09/10/2018] [Indexed: 01/15/2023] Open
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Filipp ME, Travis BJ, Henry SS, Idzikowski EC, Magnuson SA, Loh MY, Hellenbrand DJ, Hanna AS. Differences in neuroplasticity after spinal cord injury in varying animal models and humans. Neural Regen Res 2019; 14:7-19. [PMID: 30531063 PMCID: PMC6263009 DOI: 10.4103/1673-5374.243694] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Rats have been the primary model to study the process and underlying mechanisms of recovery after spinal cord injury. Two weeks after a severe spinal cord contusion, rats can regain weight-bearing abilities without therapeutic interventions, as assessed by the Basso, Beattie and Bresnahan locomotor scale. However, many human patients suffer from permanent loss of motor function following spinal cord injury. While rats are the most understood animal model, major differences in sensorimotor pathways between quadrupeds and bipeds need to be considered. Understanding the major differences between the sensorimotor pathways of rats, non-human primates, and humans is a start to improving targets for treatments of human spinal cord injury. This review will discuss the neuroplasticity of the brain and spinal cord after spinal cord injury in rats, non-human primates, and humans. A brief overview of emerging interventions to induce plasticity in humans with spinal cord injury will also be discussed.
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Affiliation(s)
- Mallory E Filipp
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Benjamin J Travis
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Stefanie S Henry
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Emma C Idzikowski
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Sarah A Magnuson
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Megan Yf Loh
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | | | - Amgad S Hanna
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
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Li W, An D, Tong X, Liu W, Xiao F, Ren J, Niu R, Tang Y, Zhou B, Lei D, Jiang Y, Luo C, Yao D, Gong Q, Zhou D. Different patterns of white matter changes after successful surgery of mesial temporal lobe epilepsy. NEUROIMAGE-CLINICAL 2018; 21:101631. [PMID: 30553761 PMCID: PMC6411915 DOI: 10.1016/j.nicl.2018.101631] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/29/2018] [Accepted: 12/07/2018] [Indexed: 02/05/2023]
Abstract
Objectives To explore the dynamic changes of white matters following anterior temporal lobectomy (ATL) in mesial temporal lobe epilepsy (MTLE) patients who achieved seizure-free at two-year follow-up. Methods Diffusion tensor imaging (DTI) was obtained in ten MTLE patients at five serial time points: before surgery, three months, six months, 12 months and 24 months after surgery, as well as in 11 age- and sex-matched healthy controls at one time point. Regions with significant postoperative fractional anisotropy (FA) changes and their dynamic changes were confirmed by comparing all preoperative and postoperative data using Tract-Based Spatial Statistics (TBSS). Results After successful ATL, significant FA changes were found in widespread ipsilateral and contralateral white matter regions (P <.05, FWE correction). Ipsilateral external capsule, cingulum, superior corona radiate, body of corpus callosum, inferior longitudinal fasciculus, optic radiation and contralateral inferior cerebellar peduncle, inferior longitudinal fasciculus showed significant FA decrease at three months after surgery, without further changes. Ipsilateral superior cerebellar peduncle and contralateral corpus callosum, anterior corona radiate, external capsule, optic radiation showed significant FA decrease at three months follow up but increase later. Ipsilateral cerebral peduncle and contralateral middle cerebellar peduncle showed significant FA decrease at three months follow up, with further decrease after that. While ipsilateral posterior limb of internal capsule, retrolenticular part of internal capsule and contralateral posterior corona radiate showed significant FA increase after surgery. Conclusions FA changes after successful ATL presented as four distinct patterns, reflecting different structural adaptions following epilepsy surgery. Some FA increases indicated the reversibility of preoperative diffusion abnormalities and the possibility of structural reorganization, especially in the contralateral hemisphere. Widespread white matter abnormalities existed in mesial temporal lobe epilepsy. We explored longitudinal DTI changes at five serial time points before and after anterior temporal lobectomy. We found four distinct patterns of diffusion changes, reflecting different structural adaptions following epilepsy surgery. Structural reorganization did occur after surgery, especially in contralateral hemisphere.
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Affiliation(s)
- Wei Li
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Dongmei An
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xin Tong
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Wenyu Liu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Fenglai Xiao
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jiechuan Ren
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Running Niu
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yingying Tang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Baiwan Zhou
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Du Lei
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yuchao Jiang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Cheng Luo
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Dezhong Yao
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Qiyong Gong
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Dong Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
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Seif M, Curt A, Thompson AJ, Grabher P, Weiskopf N, Freund P. Quantitative MRI of rostral spinal cord and brain regions is predictive of functional recovery in acute spinal cord injury. Neuroimage Clin 2018; 20:556-563. [PMID: 30175042 PMCID: PMC6115607 DOI: 10.1016/j.nicl.2018.08.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 07/11/2018] [Accepted: 08/17/2018] [Indexed: 10/28/2022]
Abstract
Objective To reveal the immediate extent of trauma-induced neurodegenerative changes rostral to the level of lesion and determine the predictive clinical value of quantitative MRI (qMRI) following acute spinal cord injury (SCI). Methods Twenty-four acute SCI patients and 23 healthy controls underwent a high-resolution T1-weighted protocol. Eighteen of those patients and 20 of controls additionally underwent a multi-parameter mapping (MPM) MRI protocol sensitive to the content of tissue structure, including myelin and iron. Patients were examined clinically at baseline, 2, 6, 12, and 24 months post-SCI. We assessed volume and microstructural changes in the spinal cord and brain using T1-weighted MRI, magnetization transfer (MT), longitudinal relaxation rate (R1), and effective transverse relaxation rate (R2*) maps. Regression analysis determined associations between acute qMRI parameters and recovery. Results At baseline, cord area and its anterior-posterior width were decreased in patients, whereas MT, R1, and R2* parameters remained unchanged in the cord. Within the cerebellum, volume decrease was paralleled by increases of MT and R2* parameters. Early grey matter changes were observed within the primary motor cortex and limbic system. Importantly, early volume and microstructural changes of the cord and cerebellum predicted functional recovery following injury. Conclusions Neurodegenerative changes rostral to the level of lesion occur early in SCI, with varying temporal and spatial dynamics. Early qMRI markers of spinal cord and cerebellum are predictive of functional recovery. These neuroimaging biomarkers may supplement clinical assessments and provide insights into the potential of therapeutic interventions to enhance neural plasticity.
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Key Words
- APW, anterior posterior width
- Acute micro-structural changes
- Brain and spinal cord atrophy
- ISNCSCI, international standards for the neurological classification of spinal cord injury
- LRW, left right width
- MPM, multi-parameter mapping
- MT, magnetization transfer
- PD*, effective proton density
- Quantitative neuroimaging
- R1, longitudinal relaxation rate
- R2*, effective transverse relaxation rate
- ROI, region of interest
- SCA, spinal cord area
- SCI, spinal cord injury
- SCIM, spinal cord independence measure
- Spinal cord injury
- VBCT, voxel based cortical thickness
- VBM, voxel based morphometry
- VBQ, voxel based quantification
- Voxel-based morphometry and quantification
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Affiliation(s)
- Maryam Seif
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Armin Curt
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland
| | - Alan J Thompson
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK
| | - Patrick Grabher
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, UK
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, University of Zurich, Switzerland; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, UK.
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Mohammed H, Hollis ER. Cortical Reorganization of Sensorimotor Systems and the Role of Intracortical Circuits After Spinal Cord Injury. Neurotherapeutics 2018; 15:588-603. [PMID: 29882081 PMCID: PMC6095783 DOI: 10.1007/s13311-018-0638-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Abstract
The plasticity of sensorimotor systems in mammals underlies the capacity for motor learning as well as the ability to relearn following injury. Spinal cord injury, which both deprives afferent input and interrupts efferent output, results in a disruption of cortical somatotopy. While changes in corticospinal axons proximal to the lesion are proposed to support the reorganization of cortical motor maps after spinal cord injury, intracortical horizontal connections are also likely to be critical substrates for rehabilitation-mediated recovery. Intrinsic connections have been shown to dictate the reorganization of cortical maps that occurs in response to skilled motor learning as well as after peripheral injury. Cortical networks incorporate changes in motor and sensory circuits at subcortical or spinal levels to induce map remodeling in the neocortex. This review focuses on the reorganization of cortical networks observed after injury and posits a role of intracortical circuits in recovery.
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Affiliation(s)
- Hisham Mohammed
- Burke Neurological Institute, 785 Mamaroneck Avenue, White Plains, NY, 10605, USA
| | - Edmund R Hollis
- Burke Neurological Institute, 785 Mamaroneck Avenue, White Plains, NY, 10605, USA.
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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31
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Second-order spinal cord pathway contributes to cortical responses after long recoveries from dorsal column injury in squirrel monkeys. Proc Natl Acad Sci U S A 2018; 115:4258-4263. [PMID: 29610299 DOI: 10.1073/pnas.1718826115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Months after the occurrence of spinal cord dorsal column lesions (DCLs) at the cervical level, neural responses in the hand representation of somatosensory area 3b hand cortex recover, along with hand use. To examine whether the second-order spinal cord pathway contributes to this functional recovery, we injected cholera toxin subunit B (CTB) into the hand representation in the cuneate nucleus (Cu) to label the spinal cord neurons, and related results to cortical reactivation in four squirrel monkeys (Saimiri boliviensis) at least 7 months after DCL. In two monkeys with complete DCLs, few CTB-labeled neurons were present below the lesion, and few neurons in the affected hand region in area 3b responded to touch on the hand. In two other cases with large but incomplete DCLs, CTB-labeled neurons were abundant below the lesion, and the area 3b hand cortex responded well to tactile stimulation in a roughly somatotopic organization. The proportions of labeled neurons in the spinal cord hand region reflected the extent of cortical reactivation to the hand. Comparing monkeys with short and long recovery times suggests that the numbers of labeled neurons below the lesion increase with time following incomplete DCLs (<95%) but decrease with time after nearly complete DCLs (≥95%). Taken together, these results suggest that the second-order spinal cord pathway facilitates cortical reactivation, likely through the potentiation of persisting tactile inputs from the hand to the Cu over months of postlesion recovery.
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Thomaty S, Pezard L, Xerri C, Brezun JM. Acute granulocyte macrophage-colony stimulating factor treatment modulates neuroinflammatory processes and promotes tactile recovery after spinal cord injury. Neuroscience 2017; 349:144-164. [DOI: 10.1016/j.neuroscience.2017.02.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 02/17/2017] [Accepted: 02/17/2017] [Indexed: 11/25/2022]
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Chen Q, Zheng W, Chen X, Wan L, Qin W, Qi Z, Chen N, Li K. Brain Gray Matter Atrophy after Spinal Cord Injury: A Voxel-Based Morphometry Study. Front Hum Neurosci 2017; 11:211. [PMID: 28503142 PMCID: PMC5408078 DOI: 10.3389/fnhum.2017.00211] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 04/11/2017] [Indexed: 01/15/2023] Open
Abstract
The aim of this study was to explore possible changes in whole brain gray matter volume (GMV) after spinal cord injury (SCI) using voxel-based morphometry (VBM), and to study their associations with the injury duration, severity, and clinical variables. In total, 21 patients with SCI (10 with complete and 11 with incomplete SCI) and 21 age- and sex-matched healthy controls (HCs) were recruited. The 3D high-resolution T1-weighted structural images of all subjects were obtained using a 3.0 Tesla MRI system. Disease duration and American Spinal Injury Association (ASIA) Scale scores were also obtained from each patient. Voxel-based morphometry analysis was carried out to investigate the differences in GMV between patients with SCI and HCs, and between the SCI sub-groups. Associations between GMV and clinical variables were also analyzed. Compared with HCs, patients with SCI showed significant GMV decrease in the dorsal anterior cingulate cortex, bilateral anterior insular cortex, bilateral orbital frontal cortex (OFC), and right superior temporal gyrus. No significant difference in GMV in these areas was found either between the complete and incomplete SCI sub-groups, or between the sub-acute (duration <1 year) and chronic (duration >1 year) sub-groups. Finally, the GMV of the right OFC was correlated with the clinical motor scores of left extremities in not only all SCI patients, but especially the CSCI subgroup. In the sub-acute subgroup, we found a significant positive correlation between the dACC GMV and the total clinical motor scores, and a significant negative correlation between right OFC GMV and the injury duration. These findings indicate that SCI can cause remote atrophy of brain gray matter, especially in the salient network. In general, the duration and severity of SCI may be not associated with the degree of brain atrophy in total SCI patients, but there may be associations between them in subgroups.
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Affiliation(s)
- Qian Chen
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China
| | - Weimin Zheng
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China.,Department of Radiology, Dongfang Hospital Beijing University of Chinese MedicineBeijing, China
| | - Xin Chen
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China
| | - Lu Wan
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China
| | - Wen Qin
- Department of Radiology, Tianjin Medical University General HospitalTianjin, China
| | - Zhigang Qi
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China
| | - Nan Chen
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China
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Afferent Fiber Remodeling in the Somatosensory Thalamus of Mice as a Neural Basis of Somatotopic Reorganization in the Brain and Ectopic Mechanical Hypersensitivity after Peripheral Sensory Nerve Injury. eNeuro 2017; 4:eN-NWR-0345-16. [PMID: 28396882 PMCID: PMC5378058 DOI: 10.1523/eneuro.0345-16.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/22/2017] [Accepted: 03/03/2017] [Indexed: 01/12/2023] Open
Abstract
Plastic changes in the CNS in response to peripheral sensory nerve injury are a series of complex processes, ranging from local circuit remodeling to somatotopic reorganization. However, the link between circuit remodeling and somatotopic reorganization remains unclear. We have previously reported that transection of the primary whisker sensory nerve causes the abnormal rewiring of lemniscal fibers (sensory afferents) on a neuron in the mouse whisker sensory thalamus (V2 VPM). In the present study, using transgenic mice whose lemniscal fibers originate from the whisker sensory principle trigeminal nucleus (PrV2) are specifically labeled, we identified that the transection induced retraction of PrV2-originating lemniscal fibers and invasion of those not originating from PrV2 in the V2 VPM. This anatomical remodeling with somatotopic reorganization was highly correlated with the rewiring of lemniscal fibers. Origins of the non-PrV2-origin lemniscal fibers in the V2 VPM included the mandibular subregion of trigeminal nuclei and the dorsal column nuclei (DCNs), which normally represent body parts other than whiskers. The transection also resulted in ectopic receptive fields of V2 VPM neurons and extraterritorial pain behavior on the uninjured mandibular region of the face. The anatomical remodeling, emergence of ectopic receptive fields, and extraterritorial pain behavior all concomitantly developed within a week and lasted more than three months after the transection. Our findings, thus, indicate a strong linkage between these plastic changes after peripheral sensory nerve injury, which may provide a neural circuit basis underlying large-scale reorganization of somatotopic representation and abnormal ectopic sensations.
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35
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Makin TR, Bensmaia SJ. Stability of Sensory Topographies in Adult Cortex. Trends Cogn Sci 2017; 21:195-204. [PMID: 28214130 DOI: 10.1016/j.tics.2017.01.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 12/30/2016] [Accepted: 01/03/2017] [Indexed: 01/03/2023]
Abstract
Textbooks teach us that the removal of sensory input to sensory cortex, for example, following arm amputation, results in massive reorganisation in the adult brain. In this opinion article, we critically examine evidence for functional reorganisation of sensory cortical representations, focusing on the sequelae of arm amputation on somatosensory topographies. Based on literature from human and non-human primates, we conclude that the cortical representation of the limb remains remarkably stable despite the loss of its main peripheral input. Furthermore, the purportedly massive reorganisation results primarily from the formation or potentiation of new pathways in subcortical structures and does not produce novel functional sensory representations. We discuss the implications of the stability of sensory representations on the development of upper-limb neuroprostheses.
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Affiliation(s)
- Tamar R Makin
- FMRIB Centre, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX39DU, UK; Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK.
| | - Sliman J Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
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Abstract
We do not know precisely why pain develops and becomes chronic after peripheral nerve injury (PNI), but it is likely due to biological and psychological factors. Here, we tested the hypotheses that (1) high Pain Catastrophizing Scale (PCS) scores at the time of injury and repair are associated with pain and cold sensitivity after 1-year recovery and (2) insula gray matter changes reflect the course of injury and improvements over time. Ten patients with complete median and/or ulnar nerve transections and surgical repair were tested ∼3 weeks after surgical nerve repair (time 1) and ∼1 year later for 6 of the 10 patients (time 2). Patients and 10 age-/sex-matched healthy controls completed questionnaires that assessed pain (patients) and personality and underwent quantitative sensory testing and 3T MRI to assess cortical thickness. In patients, pain intensity and neuropathic pain correlated with pain catastrophizing. Time 1 pain catastrophizing trended toward predicting cold pain thresholds at time 2, and at time 1 cortical thickness of the right insula was reduced. At time 2, chronic pain was related to the time 1 pain-PCS relationship and cold sensitivity, pain catastrophizing correlated with cold pain threshold, and insula thickness reversed to control levels. This study highlights the interplay between personality, sensory function, and pain in patients following PNI and repair. The PCS-pain association suggests that a focus on affective or negative components of pain could render patients vulnerable to chronic pain. Cold sensitivity and structural insula changes may reflect altered thermosensory or sensorimotor awareness representations.
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37
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Reed JL, Liao CC, Qi HX, Kaas JH. Plasticity and Recovery After Dorsal Column Spinal Cord Injury in Nonhuman Primates. J Exp Neurosci 2016; 10:11-21. [PMID: 27578996 PMCID: PMC4991577 DOI: 10.4137/jen.s40197] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/26/2016] [Accepted: 06/28/2016] [Indexed: 12/15/2022] Open
Abstract
Here, we review recent work on plasticity and recovery after dorsal column spinal cord injury in nonhuman primates. Plasticity in the adult central nervous system has been established and studied for the past several decades; however, capacities and limits of plasticity are still under investigation. Studies of plasticity include assessing multiple measures before and after injury in animal models. Such studies are particularly important for improving recovery after injury in patients. In summarizing work by our research team and others, we suggest how the findings from plasticity studies in nonhuman primate models may affect therapeutic interventions for conditions involving sensory loss due to spinal cord injury.
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Affiliation(s)
- Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
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38
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Qi HX, Wang F, Liao CC, Friedman RM, Tang C, Kaas JH, Avison MJ. Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys. Neuroimage 2016; 142:431-453. [PMID: 27523450 DOI: 10.1016/j.neuroimage.2016.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/23/2016] [Accepted: 08/09/2016] [Indexed: 11/17/2022] Open
Abstract
After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution cerebral blood volume-based functional magnetic resonance imaging (CBV-fMRI) mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6weeks after a mid-cervical level contralateral DC lesion. Both low and high intensity ES of digits revealed the expected somatotopy of the area 3b hand representation in pre-lesion monkeys, while in areas 1 and 3a, high intensity stimulation was more effective in activating somatotopic patterns. Six weeks post-lesion, and irrespective of the severity of loss of direct DC inputs (98%, 79%, 40%), somatosensory cortical area 3b of all three animals showed near complete recovery in terms of somatotopy and responsiveness to low and high intensity ES. However there was significant variability in the patterns and amplitudes of reactivation of individual digit territories within and between animals, reflecting differences in the degree of permanent and/or transient silencing of primary DC and secondary inputs 2weeks post-lesion, and their spatio-temporal trajectories of recovery between 2 and 6weeks. Similar variations in the silencing and recovery of somatotopy and responsiveness to high intensity ES in areas 3a and 1 are consistent with individual differences in damage to and recovery of DC and spinocuneate pathways, and possibly the potentiation of spinothalamic pathways. Thus, cortical deactivation and subsequent reactivation depends not only on the degree of DC lesion, but also on the severity and duration of loss of secondary as well as primary inputs revealed by low and high intensity ES.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
| | - Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Robert M Friedman
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Chaohui Tang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Malcolm J Avison
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA; Pharmacology, Vanderbilt University, Nashville, TN 37240, USA
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Increased responses in the somatosensory thalamus immediately after spinal cord injury. Neurobiol Dis 2016; 87:39-49. [DOI: 10.1016/j.nbd.2015.12.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 11/26/2015] [Accepted: 12/14/2015] [Indexed: 11/24/2022] Open
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Simon NG, Franz CK, Gupta N, Alden T, Kliot M. Central Adaptation following Brachial Plexus Injury. World Neurosurg 2016; 85:325-32. [DOI: 10.1016/j.wneu.2015.09.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 12/11/2022]
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Liao CC, Qi HX, Reed JL, Miller DJ, Kaas JH. Congenital foot deformation alters the topographic organization in the primate somatosensory system. Brain Struct Funct 2016; 221:383-406. [PMID: 25326245 PMCID: PMC4446245 DOI: 10.1007/s00429-014-0913-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/07/2014] [Indexed: 12/20/2022]
Abstract
Limbs may fail to grow properly during fetal development, but the extent to which such growth alters the nervous system has not been extensively explored. Here we describe the organization of the somatosensory system in a 6-year-old monkey (Macaca radiata) born with a deformed left foot in comparison to the results from a normal monkey (Macaca fascicularis). Toes 1, 3, and 5 were missing, but the proximal parts of toes 2 and 4 were present. We used anatomical tracers to characterize the patterns of peripheral input to the spinal cord and brainstem, as well as between thalamus and cortex. We also determined the somatotopic organization of primary somatosensory area 3b of both hemispheres using multiunit electrophysiological recording. Tracers were subcutaneously injected into matching locations of each foot to reveal their representations within the lumbar spinal cord, and the gracile nucleus (GrN) of the brainstem. Tracers injected into the representations of the toes and plantar pads of cortical area 3b labeled neurons in the ventroposterior lateral nucleus (VPL) of the thalamus. Contrary to the orderly arrangement of the foot representation throughout the lemniscal pathway in the normal monkey, the plantar representation of the deformed foot was significantly expanded and intruded into the expected representations of toes in the spinal cord, GrN, VPL, and area 3b. We also observed abnormal representation of the intact foot in the ipsilateral spinal cord and contralateral area 3b. Thus, congenital malformation influences the somatotopic representation of the deformed as well as the intact foot.
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Affiliation(s)
- Chia-Chi Liao
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA.
| | - Hui-Xin Qi
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
| | - Jamie L Reed
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
| | - Daniel J Miller
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
| | - Jon H Kaas
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
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Intracortical and Thalamocortical Connections of the Hand and Face Representations in Somatosensory Area 3b of Macaque Monkeys and Effects of Chronic Spinal Cord Injuries. J Neurosci 2015; 35:13475-86. [PMID: 26424892 DOI: 10.1523/jneurosci.2069-15.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Brains of adult monkeys with chronic lesions of dorsal columns of spinal cord at cervical levels undergo large-scale reorganization. Reorganization results in expansion of intact chin inputs, which reactivate neurons in the deafferented hand representation in the primary somatosensory cortex (area 3b), ventroposterior nucleus of the thalamus and cuneate nucleus of the brainstem. A likely contributing mechanism for this large-scale plasticity is sprouting of axons across the hand-face border. Here we determined whether such sprouting takes place in area 3b. We first determined the extent of intrinsic corticocortical connectivity between the hand and the face representations in normal area 3b. Small amounts of neuroanatomical tracers were injected in these representations close to the electrophysiologically determined hand-face border. Locations of the labeled neurons were mapped with respect to the detailed electrophysiological somatotopic maps and histologically determined hand-face border revealed in sections of the flattened cortex stained for myelin. Results show that intracortical projections across the hand-face border are few. In monkeys with chronic unilateral lesions of the dorsal columns and expanded chin representation, connections across the hand-face border were not different compared with normal monkeys. Thalamocortical connections from the hand and face representations in the ventroposterior nucleus to area 3b also remained unaltered after injury. The results show that sprouting of intrinsic connections in area 3b or the thalamocortical inputs does not contribute to large-scale cortical plasticity. Significance statement: Long-term injuries to dorsal spinal cord in adult primates result in large-scale somatotopic reorganization due to which chin inputs expand into the deafferented hand region. Reorganization takes place in multiple cortical areas, and thalamic and medullary nuclei. To what extent this brain reorganization due to dorsal column injuries is related to axonal sprouting is not known. Here we show that reorganization of primary somatosensory area 3b is not accompanied with either an increase in intrinsic cortical connections between the hand and face representations, or any change in thalamocortical inputs to these areas. Axonal sprouting that causes reorganization likely takes place at subthalamic levels.
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Liao CC, Reed JL, Kaas JH, Qi HX. Intracortical connections are altered after long-standing deprivation of dorsal column inputs in the hand region of area 3b in squirrel monkeys. J Comp Neurol 2015; 524:1494-526. [PMID: 26519356 DOI: 10.1002/cne.23921] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 10/01/2015] [Accepted: 10/26/2015] [Indexed: 11/09/2022]
Abstract
A complete unilateral lesion of the dorsal column somatosensory pathway in the upper cervical spinal cord deactivates neurons in the hand region in contralateral somatosensory cortex (areas 3b and 1). Over weeks to months of recovery, parts of the hand region become reactivated by touch on the hand or face. To determine whether changes in cortical connections potentially contribute to this reactivation, we injected tracers into electrophysiologically identified locations in cortex of area 3b representing the reactivated hand and normally activated face in adult squirrel monkeys. Our results indicated that even when only partially reactivated, most of the expected connections of area 3b remained intact. These intact connections include the majority of intrinsic connections within area 3b; feedback connections from area 1, secondary somatosensory cortex (S2), parietal ventral area (PV), and other cortical areas; and thalamic inputs from the ventroposterior lateral nucleus (VPL). In addition, tracer injections in the reactivated hand region of area 3b labeled more neurons in the face and shoulder regions of area 3b than in normal monkeys, and injections in the face region of area 3b labeled more neurons in the hand region. Unexpectedly, the intrinsic connections within area 3b hand cortex were more widespread after incomplete dorsal column lesions (DCLs) than after a complete DCL. Although these additional connections were limited, these changes in connections may contribute to the reactivation process after injuries. J. Comp. Neurol. 524:1494-1526, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
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Jutzeler CR, Curt A, Kramer JLK. Relationship between chronic pain and brain reorganization after deafferentation: A systematic review of functional MRI findings. NEUROIMAGE-CLINICAL 2015; 9:599-606. [PMID: 26740913 PMCID: PMC4644246 DOI: 10.1016/j.nicl.2015.09.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/25/2015] [Accepted: 09/29/2015] [Indexed: 11/08/2022]
Abstract
Background Mechanisms underlying the development of phantom limb pain and neuropathic pain after limb amputation and spinal cord injury, respectively, are poorly understood. The goal of this systematic review was to assess the robustness of evidence in support of “maladaptive plasticity” emerging from applications of advanced functional magnetic resonance imaging (MRI). Methods Using MeSH heading search terms in PubMed and SCOPUS, a systematic review was performed querying published manuscripts. Results From 146 candidate publications, 10 were identified as meeting the inclusion criteria. Results from fMRI investigations provided some level of support for maladaptive cortical plasticity, including longitudinal studies that demonstrated a change in functional organization related to decreases in pain. However, a number of studies have reported no relationship between reorganization, pain and deafferentation, and emerging evidence has also suggested the opposite — that is, chronic pain is associated with preserved cortical function. Conclusion Based solely on advanced functional neuroimaging results, there is only limited evidence for a relationship between chronic pain intensity and reorganization after deafferentation. The review demonstrates the need for additional neuroimaging studies to clarify the relationship between chronic pain and reorganization. There is evidence of a relationship between brain reorganization, deafferentation, and chronic pain. Emerging evidence suggests that reorganization in the CNS could be an adaptive process, preventing the emergence of pain. Future studies adopting standardized protocols are needed to clarify the role of chronic pain and plasticity in the brain.
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Affiliation(s)
- C R Jutzeler
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - A Curt
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - J L K Kramer
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; ICORD, School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
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Liao CC, DiCarlo GE, Gharbawie OA, Qi HX, Kaas JH. Spinal cord neuron inputs to the cuneate nucleus that partially survive dorsal column lesions: A pathway that could contribute to recovery after spinal cord injury. J Comp Neurol 2015; 523:2138-60. [PMID: 25845707 PMCID: PMC4575617 DOI: 10.1002/cne.23783] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/02/2015] [Accepted: 04/02/2015] [Indexed: 01/29/2023]
Abstract
Dorsal column lesions at a high cervical level deprive the cuneate nucleus and much of the somatosensory system of its major cutaneous inputs. Over weeks of recovery, much of the hand representations in the contralateral cortex are reactivated. One possibility for such cortical reactivation by hand afferents is that preserved second-order spinal cord neurons reach the cuneate nucleus through pathways that circumvent the dorsal column lesions, contributing to cortical reactivation in an increasingly effective manner over time. To evaluate this possibility, we first injected anatomical tracers into the cuneate nucleus and plotted the distributions of labeled spinal cord neurons and fibers in control monkeys. Large numbers of neurons in the dorsal horn of the cervical spinal cord were labeled, especially ipsilaterally in lamina IV. Labeled fibers were distributed in the cuneate fasciculus and lateral funiculus. In three other squirrel monkeys, unilateral dorsal column lesions were placed at the cervical segment 4 level and tracers were injected into the ipsilateral cuneate nucleus. Two weeks later, a largely unresponsive hand representation in contralateral somatosensory cortex confirmed the effectiveness of the dorsal column lesion. However, tracer injections in the cuneate nucleus labeled only about 5% of the normal number of dorsal horn neurons, mainly in lamina IV, below the level of lesions. Our results revealed a small second-order pathway to the cuneate nucleus that survives high cervical dorsal column lesions by traveling in the lateral funiculus. This could be important for cortical reactivation by hand afferents, and recovery of hand use.
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Affiliation(s)
- Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | | | - Omar A. Gharbawie
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jon H. Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
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Grabher P, Callaghan MF, Ashburner J, Weiskopf N, Thompson AJ, Curt A, Freund P. Tracking sensory system atrophy and outcome prediction in spinal cord injury. Ann Neurol 2015; 78:751-61. [PMID: 26290444 PMCID: PMC4737098 DOI: 10.1002/ana.24508] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/17/2015] [Accepted: 08/18/2015] [Indexed: 11/17/2022]
Abstract
Objective In patients with subacute spinal cord injury (SCI), the motor system undergoes progressive structural changes rostral to the lesion, which are associated with motor outcome. The extent to which the sensory system is affected and how this relates to sensory outcome are uncertain. Methods Changes in the sensory system were prospectively followed by applying a comprehensive magnetic resonance imaging (MRI) protocol to 14 patients with subacute traumatic SCI at baseline, 2 months, 6 months, and 12 months after injury, combined with a full neurological examination and comprehensive pain assessment. Eighteen controls underwent the same MRI protocol. T1‐weighted volumes, myelin‐sensitive magnetization transfer saturation (MT), and longitudinal relaxation rate (R1) mapping provided data on spinal cord and brain morphometry and microstructure. Regression analysis assessed the relationship between MRI readouts and sensory outcomes. Results At 12 months from baseline, sensory scores were unchanged and below‐level neuropathic pain became prominent. Compared with controls, patients showed progressive degenerative changes in cervical cord and brain morphometry across the sensory system. At 12 months, MT and R1 were reduced in areas of structural decline. Sensory scores at 12 months correlated with rate of change in cord area and brain volume and decreased MT in the spinal cord at 12 months. Interpretation This study has demonstrated progressive atrophic and microstructural changes across the sensory system with a close relation to sensory outcome. Structural MRI protocols remote from the site of lesion provide new insights into neuronal degeneration underpinning sensory disturbance and have potential as responsive biomarkers of rehabilitation and treatment interventions. Ann Neurol 2015;78:Ann Neurol 2015;78:679–696
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Affiliation(s)
- Patrick Grabher
- Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Martina F Callaghan
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom
| | - John Ashburner
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Nikolaus Weiskopf
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.,Department of Neurophysics, Max Planck Institute for Human Cognitive, and Brain Sciences, Leipzig, Germany
| | - Alan J Thompson
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Armin Curt
- Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.,Department of Neurophysics, Max Planck Institute for Human Cognitive, and Brain Sciences, Leipzig, Germany.,Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom
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Mayer de Oliveira A, Cabral Miranda F. Are the mechanisms driving somatosensory reorganization cortical or subcortical? Front Neuroanat 2014; 8:62. [PMID: 25071467 PMCID: PMC4081762 DOI: 10.3389/fnana.2014.00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 06/17/2014] [Indexed: 12/04/2022] Open
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Moxon KA, Oliviero A, Aguilar J, Foffani G. Cortical reorganization after spinal cord injury: always for good? Neuroscience 2014; 283:78-94. [PMID: 24997269 DOI: 10.1016/j.neuroscience.2014.06.056] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/09/2014] [Accepted: 06/25/2014] [Indexed: 12/29/2022]
Abstract
Plasticity constitutes the basis of behavioral changes as a result of experience. It refers to neural network shaping and re-shaping at the global level and to synaptic contacts remodeling at the local level, either during learning or memory encoding, or as a result of acute or chronic pathological conditions. 'Plastic' brain reorganization after central nervous system lesions has a pivotal role in the recovery and rehabilitation of sensory and motor dysfunction, but can also be "maladaptive". Moreover, it is clear that brain reorganization is not a "static" phenomenon but rather a very dynamic process. Spinal cord injury immediately initiates a change in brain state and starts cortical reorganization. In the long term, the impact of injury - with or without accompanying therapy - on the brain is a complex balance between supraspinal reorganization and spinal recovery. The degree of cortical reorganization after spinal cord injury is highly variable, and can range from no reorganization (i.e. "silencing") to massive cortical remapping. This variability critically depends on the species, the age of the animal when the injury occurs, the time after the injury has occurred, and the behavioral activity and possible therapy regimes after the injury. We will briefly discuss these dependencies, trying to highlight their translational value. Overall, it is not only necessary to better understand how the brain can reorganize after injury with or without therapy, it is also necessary to clarify when and why brain reorganization can be either "good" or "bad" in terms of its clinical consequences. This information is critical in order to develop and optimize cost-effective therapies to maximize functional recovery while minimizing maladaptive states after spinal cord injury.
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Affiliation(s)
- K A Moxon
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
| | - A Oliviero
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - J Aguilar
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - G Foffani
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain.
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Qi HX, Kaas JH, Reed JL. The reactivation of somatosensory cortex and behavioral recovery after sensory loss in mature primates. Front Syst Neurosci 2014; 8:84. [PMID: 24860443 PMCID: PMC4026759 DOI: 10.3389/fnsys.2014.00084] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 04/22/2014] [Indexed: 02/04/2023] Open
Abstract
In our experiments, we removed a major source of activation of somatosensory cortex in mature monkeys by unilaterally sectioning the sensory afferents in the dorsal columns of the spinal cord at a high cervical level. At this level, the ascending branches of tactile afferents from the hand are cut, while other branches of these afferents remain intact to terminate on neurons in the dorsal horn of the spinal cord. Immediately after such a lesion, the monkeys seem relatively unimpaired in locomotion and often use the forelimb, but further inspection reveals that they prefer to use the unaffected hand in reaching for food. In addition, systematic testing indicates that they make more errors in retrieving pieces of food, and start using visual inspection of the rotated hand to confirm the success of the grasping of the food. Such difficulties are not surprising as a complete dorsal column lesion totally deactivates the contralateral hand representation in primary somatosensory cortex (area 3b). However, hand use rapidly improves over the first post-lesion weeks, and much of the hand representational territory in contralateral area 3b is reactivated by inputs from the hand in roughly a normal somatotopic pattern. Quantitative measures of single neuron response properties reveal that reactivated neurons respond to tactile stimulation on the hand with high firing rates and only slightly longer latencies. We conclude that preserved dorsal column afferents after nearly complete lesions contribute to the reactivation of cortex and the recovery of the behavior, but second-order sensory pathways in the spinal cord may also play an important role. Our microelectrode recordings indicate that these preserved first-order, and second-order pathways are initially weak and largely ineffective in activating cortex, but they are potentiated during the recovery process. Therapies that would promote this potentiation could usefully enhance recovery after spinal cord injury.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University Nashville, TN, USA
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University Nashville, TN, USA
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Cortical neuron response properties are related to lesion extent and behavioral recovery after sensory loss from spinal cord injury in monkeys. J Neurosci 2014; 34:4345-63. [PMID: 24647955 DOI: 10.1523/jneurosci.4954-13.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Lesions of the dorsal columns at a mid-cervical level render the hand representation of the contralateral primary somatosensory cortex (area 3b) unresponsive. Over weeks of recovery, most of this cortex becomes responsive to touch on the hand. Determining functional properties of neurons within the hand representation is critical to understanding the neural basis of this adaptive plasticity. Here, we recorded neural activity across the hand representation of area 3b with a 100-electrode array and compared results from owl monkeys and squirrel monkeys 5-10 weeks after lesions with controls. Even after extensive lesions, performance on reach-to-grasp tasks returned to prelesion levels, and hand touches activated territories mainly within expected cortical locations. However, some digit representations were abnormal, such that receptive fields of presumably reactivated neurons were larger and more often involved discontinuous parts of the hand compared with controls. Hand stimulation evoked similar neuronal firing rates in lesion and control monkeys. By assessing the same monkeys with multiple measures, we determined that properties of neurons in area 3b were highly correlated with both the lesion severity and the impairment of hand use. We propose that the reactivation of neurons with near-normal response properties and the recovery of near-normal somatotopy likely supported the recovery of hand use. Given the near-completeness of the more extensive dorsal column lesions we studied, we suggest that alternate spinal afferents, in addition to the few spared primary axon afferents in the dorsal columns, likely have a major role in the reactivation pattern and return of function.
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