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Chen M, Chen Z, Xiao X, Zhou L, Fu R, Jiang X, Pang M, Xia J. Corticospinal circuit neuroplasticity may involve silent synapses: Implications for functional recovery facilitated by neuromodulation after spinal cord injury. IBRO Neurosci Rep 2022; 14:185-194. [PMID: 36824667 PMCID: PMC9941655 DOI: 10.1016/j.ibneur.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/15/2022] [Indexed: 10/15/2022] Open
Abstract
Spinal cord injury (SCI) leads to devastating physical consequences, such as severe sensorimotor dysfunction even lifetime disability, by damaging the corticospinal system. The conventional opinion that SCI is intractable due to the poor regeneration of neurons in the adult central nervous system (CNS) needs to be revisited as the CNS is capable of considerable plasticity, which underlie recovery from neural injury. Substantial spontaneous neuroplasticity has been demonstrated in the corticospinal motor circuitry following SCI. Some of these plastic changes appear to be beneficial while others are detrimental toward locomotor function recovery after SCI. The beneficial corticospinal plasticity in the spared corticospinal circuits can be harnessed therapeutically by multiple contemporary neuromodulatory approaches, especially the electrical stimulation-based modalities, in an activity-dependent manner to improve functional outcomes in post-SCI rehabilitation. Silent synapse generation and unsilencing contribute to profound neuroplasticity that is implicated in a variety of neurological disorders, thus they may be involved in the corticospinal motor circuit neuroplasticity following SCI. Exploring the underlying mechanisms of silent synapse-mediated neuroplasticity in the corticospinal motor circuitry that may be exploited by neuromodulation will inform a novel direction for optimizing therapeutic repair strategies and rehabilitative interventions in SCI patients.
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Key Words
- AMPARs, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors
- BDNF, brain-derived neurotrophic factor
- BMIs, brain-machine interfaces
- CPG, central pattern generator
- CST, corticospinal tract
- Corticospinal motor circuitry
- DBS, deep brain stimulation
- ESS, epidural spinal stimulation
- MEPs, motor-evoked potentials
- NHPs, non-human primates
- NMDARs, N-methyl-d-aspartate receptors
- Neuromodulation
- Neuroplasticity
- PSNs, propriospinal neurons
- Rehabilitation
- SCI, spinal cord injury
- STDP, spike timing-dependent plasticity
- Silent synapses
- Spinal cord injury
- TBS, theta burst stimulation
- TMS, transcranial magnetic stimulation
- TrkB, tropomyosin-related kinase B
- cTBS, continuous TBS
- iTBS, intermittent TBS
- mTOR, mammalian target of rapamycin
- rTMS, repetitive TMS
- tDCS, transcranial direct current stimulation
- tcSCS, transcutaneous spinal cord stimulation
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Affiliation(s)
- Mingcong Chen
- Department of Orthopedics and Traumatology, Shenzhen University General Hospital, Shenzhen, Guangdong 518055, China
| | - Zuxin Chen
- Shenzhen Key Laboratory of Drug Addiction, Shenzhen Neher Neural Plasticity Laboratory, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS); Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, Guangdong 518055, China
| | - Xiao Xiao
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence, Ministry of Education; Behavioral and Cognitive Neuroscience Center, Institute of Science and Technology for Brain-Inspired Intelligence; MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200433, China
| | - Libing Zhou
- Guangdong-Hongkong-Macau CNS Regeneration Institute of Jinan University, Key Laboratory of CNS Regeneration (Jinan University)-Ministry of Education, Guangzhou, Guangdong 510632, China
| | - Rao Fu
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong 518100, China
| | - Xian Jiang
- Institute of Neurological and Psychiatric Disorder, Shenzhen Bay laboratory, Shenzhen, Guangdong 518000, China
| | - Mao Pang
- Department of Spine Surgery, the Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, Guangzhou, Guangdong 510630, China
| | - Jianxun Xia
- Department of Basic Medical Sciences, Yunkang School of Medicine and Health, Nanfang College, Guangzhou, Guangdong 510970, China,Corresponding author.
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Lin Y, Xu Y, Feng H, You L, Dong J, Gao Z, Peng S, Deng Y, Wu P. Involuntary, forced or voluntary exercise can ameliorate the cognitive deficits by enhancing levels of hippocampal NMDAR1, pAMPAR1 and pCaMKII in a model of vascular dementia. Neurol Res 2021; 43:349-357. [PMID: 33393454 DOI: 10.1080/01616412.2020.1866351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Objectives: To investigate the effect on vascular dementia of involuntary exercise induced by functional electrical stimulation and of forced and voluntary exercise, focusing on the recovery of cognitive function and using a rat model of dementia.Methods: A demential model was created in Wistar rats who were then given forced exercise, allowed voluntary exercise (wheel running) or had exercise induced through functional electrical stimulation. Their responses were quantified using a Morris water maze and by measuring long-term potentiation in the hippocampus. Immunohistochemical staining was used to evaluate neurogenesis in the hippocampus and Nissl staining was applied to visualize viable neuron loss in the DG sector. In addition, the levels of NMDAR1, AMPAR1, pAMPAR1, pCaMKII, CaMKII, Bcl-2 and Bax in the hippocampus were assessed by western blotting.Results: All of the exercise groups showed a recovery of cognitive performance and improved long-term potentiation. The three modes of exercise all increased the number of DCX immunopositive cells and reduced losses of intact-appearing neurons in the hippocampal DG zones roughly equally. All proved about equally effective in increasing the levels of NMDAR1, pAMPAR1 and pCaMKII and increasing the Bcl-2/Bax ratio to protect neurons from apoptosis.Conclusion: Exercise induced by electrical stimulation has beneficial effects comparable to those of other types of exercise for alleviating the cognitive deficits of vascular dementia.
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Affiliation(s)
- Yangyang Lin
- Department of Rehabilitation Medicine, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yangfan Xu
- Department of Rehabilitation Medicine, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Huiting Feng
- Department of Rehabilitation Medicine, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Longfei You
- Department of Rehabilitation Medicine, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Juntao Dong
- Department of Rehabilitation, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zunlin Gao
- Department of Rehabilitation, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Suiying Peng
- Department of Rehabilitation Medicine, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yujie Deng
- Department of Rehabilitation Medicine, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Peihui Wu
- Department of Joint Surgery, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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Al-Chami A, Ross A, Hayley S, Sun H. Early life stress facilitates synapse premature unsilencing to enhance AMPA receptor function in the developing hippocampus. J Neurophysiol 2020; 124:815-821. [PMID: 32783592 DOI: 10.1152/jn.00339.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic early life stress (ELS) increases vulnerability to psychopathologies and cognitive deficits in adulthood by disrupting the function of related neural circuits. However, whether this disruption emerges early in the developing brain remains largely unexplored. In the current study, using an established limited-bedding and nesting model of ELS in postnatal day (P)2-10 mice, we provide direct evidence that ELS caused early modification of hippocampal glutamatergic synapses in the developing brain. We demonstrated that ELS induced rapid enhancement of AMPA receptor function in hippocampal CA1 pyramidal neurons through a postsynaptic mechanism, and importantly, this was associated with premature unsilencing of NMDA receptor-only silent hippocampal synapses. These results suggest that potentiation of AMPAR function may represent an early mediator of ELS-induced alterations of neural networks in the developing brain and may potentially contribute to subsequent cognitive impairments later in life.NEW & NOTEWORTHY Early life stress (ELS) is known to increase the risk of later life cognitive deficits by disrupting neural circuit function. However, whether this disruption emerges early in the developing brain remains largely unexplored. The current study presents direct evidence that ELS prematurely unsilences hippocampal synapses to enhance AMPA receptor functions in a limited-bedding and nesting model, revealing an early mediator of ELS-induced neural circuit reorganizations.
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Affiliation(s)
- Aycheh Al-Chami
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Alysia Ross
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Shawn Hayley
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Hongyu Sun
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
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Park WJ, Fine I. New insights into cortical development and plasticity: from molecules to behavior. CURRENT OPINION IN PHYSIOLOGY 2020; 16:50-60. [PMID: 32923755 PMCID: PMC7480792 DOI: 10.1016/j.cophys.2020.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human brain contains 100 billion neurons, and each neuron can have up to 200,000 connections to other neurons. Recent advancements in neuroscience-ranging from molecular studies in animal models to behavioral studies in humans-have given us deeper insights into the development of this extraordinarily intricate system. Studies show a complex interaction between biological predispositions and environment; while the gross neuroanatomy and low-level functions develop early prior to receiving environmental inputs, functional selectivity is shaped through experience, governed by the maturation of local excitatory and inhibitory circuits and synaptic plasticity during sensitive periods early in development. Plasticity does not end with the closing of the early sensitive period - the environment continues to play an important role in learning throughout the lifespan. Recent work delineating the cascade of events that initiates, controls and ends sensitive periods, offers new hope of eventually being able to remediate various clinical conditions by selectively reopening plasticity.
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Affiliation(s)
- Woon Ju Park
- Department of Psychology, University of Washington, Seattle, WA 98195
| | - Ione Fine
- Department of Psychology, University of Washington, Seattle, WA 98195
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Persic D, Thomas ME, Pelekanos V, Ryugo DK, Takesian AE, Krumbholz K, Pyott SJ. Regulation of auditory plasticity during critical periods and following hearing loss. Hear Res 2020; 397:107976. [PMID: 32591097 PMCID: PMC8546402 DOI: 10.1016/j.heares.2020.107976] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/15/2020] [Accepted: 04/14/2020] [Indexed: 02/07/2023]
Abstract
Sensory input has profound effects on neuronal organization and sensory maps in the brain. The mechanisms regulating plasticity of the auditory pathway have been revealed by examining the consequences of altered auditory input during both developmental critical periods—when plasticity facilitates the optimization of neural circuits in concert with the external environment—and in adulthood—when hearing loss is linked to the generation of tinnitus. In this review, we summarize research identifying the molecular, cellular, and circuit-level mechanisms regulating neuronal organization and tonotopic map plasticity during developmental critical periods and in adulthood. These mechanisms are shared in both the juvenile and adult brain and along the length of the auditory pathway, where they serve to regulate disinhibitory networks, synaptic structure and function, as well as structural barriers to plasticity. Regulation of plasticity also involves both neuromodulatory circuits, which link plasticity with learning and attention, as well as ascending and descending auditory circuits, which link the auditory cortex and lower structures. Further work identifying the interplay of molecular and cellular mechanisms associating hearing loss-induced plasticity with tinnitus will continue to advance our understanding of this disorder and lead to new approaches to its treatment. During CPs, brain plasticity is enhanced and sensitive to acoustic experience. Enhanced plasticity can be reinstated in the adult brain following hearing loss. Molecular, cellular, and circuit-level mechanisms regulate CP and adult plasticity. Plasticity resulting from hearing loss may contribute to the emergence of tinnitus. Modifying plasticity in the adult brain may offer new treatments for tinnitus.
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Affiliation(s)
- Dora Persic
- University of Groningen, University Medical Center Groningen, Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713, GZ, Groningen, the Netherlands
| | - Maryse E Thomas
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear and Department of Otorhinolaryngology and Head/Neck Surgery, Harvard Medical School, Boston, MA, USA
| | - Vassilis Pelekanos
- Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, University Park, Nottingham, UK
| | - David K Ryugo
- Hearing Research, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia; School of Medical Sciences, UNSW Sydney, Sydney, NSW, 2052, Australia; Department of Otolaryngology, Head, Neck & Skull Base Surgery, St Vincent's Hospital, Sydney, NSW, 2010, Australia
| | - Anne E Takesian
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear and Department of Otorhinolaryngology and Head/Neck Surgery, Harvard Medical School, Boston, MA, USA
| | - Katrin Krumbholz
- Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, University Park, Nottingham, UK
| | - Sonja J Pyott
- University of Groningen, University Medical Center Groningen, Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713, GZ, Groningen, the Netherlands.
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