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Harris AC, Jin XT, Greer JE, Povlishock JT, Jacobs KM. Somatostatin interneurons exhibit enhanced functional output and resilience to axotomy after mild traumatic brain injury. Neurobiol Dis 2022; 171:105801. [PMID: 35753625 PMCID: PMC9383472 DOI: 10.1016/j.nbd.2022.105801] [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: 04/04/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 11/01/2022] Open
Abstract
Mild traumatic brain injury (mTBI) gives rise to a remarkable breadth of pathobiological consequences, principal among which are traumatic axonal injury and perturbation of the functional integrity of neuronal networks that may arise secondary to the elimination of the presynaptic contribution of axotomized neurons. Because there exists a vast diversity of neocortical neuron subtypes, it is imperative to elucidate the relative vulnerability to axotomy among different subtypes. Toward this end, we exploited SOM-IRES-Cre mice to investigate the consequences of the central fluid percussion model of mTBI on the microanatomical integrity and the functional efficacy of the somatostatin (SOM) interneuron population, one of the principal subtypes of neocortical interneuron. We found that the SOM population is resilient to axotomy, representing only 10% of the global burden of inhibitory interneuron axotomy, a result congruous with past work demonstrating that parvalbumin (PV) interneurons bear most of the burden of interneuron axotomy. However, the intact structure of SOM interneurons after injury did not translate to normal cellular function. One day after mTBI, the SOM population is more intrinsically excitable and demonstrates enhanced synaptic efficacy upon post-synaptic layer 5 pyramidal neurons as measured by optogenetics, yet the global evoked inhibitory tone within layer 5 is stable. Simultaneously, there exists a significant increase in the frequency of miniature inhibitory post-synaptic currents within layer 5 pyramidal neurons. These results are consistent with a scheme in which 1 day after mTBI, SOM interneurons are stimulated to compensate for the release from inhibition of layer 5 pyramidal neurons secondary to the disproportionate axotomy of PV interneurons. The enhancement of SOM interneuron intrinsic excitability and synaptic efficacy may represent the initial phase of a dynamic process of attempted autoregulation of neocortical network homeostasis secondary to mTBI.
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Affiliation(s)
- Alan C Harris
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, United States of America.
| | - Xiao-Tao Jin
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, United States of America.
| | - John E Greer
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, United States of America.
| | - John T Povlishock
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, United States of America.
| | - Kimberle M Jacobs
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, United States of America.
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2
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Jacotte-Simancas A, Middleton JW, Stielper ZF, Edwards S, Molina PE, Gilpin NW. Brain Injury Effects on Neuronal Activation and Synaptic Transmission in the Basolateral Amygdala of Adult Male and Female Wistar Rats. J Neurotrauma 2022; 39:544-559. [PMID: 35081744 PMCID: PMC8978566 DOI: 10.1089/neu.2021.0270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Traumatic brain injury (TBI) is defined as brain damage produced by an external mechanical force that leads to behavioral, cognitive, and psychiatric sequelae. The basolateral amygdala (BLA) is involved in emotional regulation, and its function and morphology are altered following TBI. Little is known about potential sex-specific effects of TBI on BLA neuronal function, but it is critical for the field to identify potential sex differences in TBI effects on brain and behavior. Here, we hypothesized that TBI would produce sex-specific acute (1 h) effects on BLA neuronal activation, excitability, and synaptic transmission in adult male and female rats. Forty-nine Wistar rats (n = 23 males and 26 females) were randomized to TBI (using lateral fluid percussion) or Sham groups in two separate studies. Study 1 used in situ hybridization (i.e., RNAscope) to measure BLA expression of c-fos (a marker of cell activation), vGlut, and vGat (markers of glutamatergic and GABAergic neurons, respectively) messenger RNA (mRNA). Study 2 used slice electrophysiology to measure intrinsic excitability and excitatory/inhibitory synaptic transmission in putative pyramidal neurons in the BLA. Physiological measures of injury severity were collected from all animals. Our results show that females exhibit increased apnea duration and reduced respiratory rate post-TBI relative to males. In male and female rats, TBI increased c-fos expression in BLA glutamatergic cells but not in BLA GABAergic cells, and TBI increased firing rate in BLA pyramidal neurons. Further, TBI increased spontaneous excitatory and inhibitory postsynaptic current (sEPSC and sIPSC) amplitude in BLA neurons of females relative to all other groups. TBI increased sEPSC frequency in BLA neurons of females relative to males but did not alter sIPSC frequency. In summary, lateral fluid percussion produced different physiological responses in male and female rats, as well as sex-specific alterations in BLA neuronal activation, excitability, and synaptic transmission 1 h after injury.
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Affiliation(s)
- Alejandra Jacotte-Simancas
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
- Alcohol and Drug of Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Jason W. Middleton
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Zachary F. Stielper
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Scott Edwards
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
- Alcohol and Drug of Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Patricia E. Molina
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
- Alcohol and Drug of Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Nicholas W. Gilpin
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
- Alcohol and Drug of Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
- Southeast Louisiana VA Healthcare System, New Orleans, Louisiana, USA
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3
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Olsen CM, Corrigan JD. Does Traumatic Brain Injury Cause Risky Substance Use or Substance Use Disorder? Biol Psychiatry 2022; 91:421-437. [PMID: 34561027 PMCID: PMC8776913 DOI: 10.1016/j.biopsych.2021.07.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/07/2021] [Accepted: 07/12/2021] [Indexed: 01/22/2023]
Abstract
There is a high co-occurrence of risky substance use among adults with traumatic brain injury (TBI), although it is unknown if the neurologic sequelae of TBI can promote this behavior. We propose that to conclude that TBI can cause risky substance use, it must be determined that TBI precedes risky substance use, that confounders with the potential to increase the likelihood of both TBI and risky substance use must be ruled out, and that there must be a plausible mechanism of action. In this review, we address these factors by providing an overview of key clinical and preclinical studies and list plausible mechanisms by which TBI could increase risky substance use. Human and animal studies have identified an association between TBI and risky substance use, although the strength of this association varies. Factors that may limit detection of this relationship include differential variability due to substance, sex, age of injury, and confounders that may influence the likelihood of both TBI and risky substance use. We propose possible mechanisms by which TBI could increase substance use that include damage-associated neuroplasticity, chronic changes in neuroimmune signaling, and TBI-associated alterations in brain networks.
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Affiliation(s)
- Christopher M Olsen
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin; Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin.
| | - John D Corrigan
- Department of Physical Medicine & Rehabilitation, Wexner Medical Center, The Ohio State University, Columbus, Ohio
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4
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Faillot M, Chaillet A, Palfi S, Senova S. Rodent models used in preclinical studies of deep brain stimulation to rescue memory deficits. Neurosci Biobehav Rev 2021; 130:410-432. [PMID: 34437937 DOI: 10.1016/j.neubiorev.2021.08.012] [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: 02/08/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 11/28/2022]
Abstract
Deep brain stimulation paradigms might be used to treat memory disorders in patients with stroke or traumatic brain injury. However, proof of concept studies in animal models are needed before clinical translation. We propose here a comprehensive review of rodent models for Traumatic Brain Injury and Stroke. We systematically review the histological, behavioral and electrophysiological features of each model and identify those that are the most relevant for translational research.
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Affiliation(s)
- Matthieu Faillot
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Antoine Chaillet
- Laboratoire des Signaux et Systèmes (L2S-UMR8506) - CentraleSupélec, Université Paris Saclay, Institut Universitaire de France, France
| | - Stéphane Palfi
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Suhan Senova
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France.
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5
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Zheng XS, Yang Q, Vazquez AL, Tracy Cui X. Imaging the Efficiency of Poly(3,4-ethylenedioxythiophene) Doped with Acid-Functionalized Carbon Nanotube and Iridium Oxide Electrode Coatings for Microstimulation. ADVANCED NANOBIOMED RESEARCH 2021; 1:2000092. [PMID: 34746928 PMCID: PMC8552016 DOI: 10.1002/anbr.202000092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/18/2021] [Indexed: 12/02/2022] Open
Abstract
Electrical microstimulation has shown promise in restoring neural deficits in humans. Electrodes coated with materials like the conducting polymer poly(3,4-ethylenedioxythiophene) doped with acid-functionalized carbon nanotubes (PEDOT/CNTs, or PC) exhibit superior charge injection than traditional metals like platinum. However, the stimulation performance of PC remains to be fully characterized. Advanced imaging techniques and transgenic tools allow for real-time observations of neural activity in vivo. Herein, microelectrodes coated with PC and iridium oxide (IrOx) (a commonly used high-charge-injection material) are implanted in GCaMP6s mice and electrical stimulation is applied while imaging neuronal calcium responses. Results show that PC-coated electrodes stimulate more intense and broader GCaMP responses than IrOx. Two-photon microscopy reveals that PC-coated electrodes activate significantly more neuronal soma and neuropil than IrOx-coated electrodes in constant-voltage stimulation and significantly more neuronal soma in constant-current stimulation. Furthermore, with the same injected charge, both materials activate more spatially confined neural elements with shorter pulses than longer pulses, providing a means to tune stimulation selectivity. Finite element analyses reveal that the PC coating creates a denser and nonuniform electric field, increasing the likelihood of activating nearby neural elements. PC coating can significantly improve energy efficiency for electrical stimulation applications.
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Affiliation(s)
- Xin S. Zheng
- Department of BioengineeringUniversity of Pittsburgh3501 Fifth Ave.PittsburghPA15213USA
| | - Qianru Yang
- Department of BioengineeringUniversity of Pittsburgh3501 Fifth Ave.PittsburghPA15213USA
| | - Alberto L. Vazquez
- Departments of Radiology and BioengineeringUniversity of Pittsburgh3025 E. Carson St.PittsburghPA15203USA
| | - Xinyan Tracy Cui
- Department of BioengineeringUniversity of Pittsburgh3501 Fifth Ave.PittsburghPA15213USA
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6
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High-frequency head impact causes chronic synaptic adaptation and long-term cognitive impairment in mice. Nat Commun 2021; 12:2613. [PMID: 33972519 PMCID: PMC8110563 DOI: 10.1038/s41467-021-22744-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
Repeated head impact exposure can cause memory and behavioral impairments. Here, we report that exposure to non-damaging, but high frequency, head impacts can alter brain function in mice through synaptic adaptation. High frequency head impact mice develop chronic cognitive impairments in the absence of traditional brain trauma pathology, and transcriptomic profiling of mouse and human chronic traumatic encephalopathy brain reveal that synapses are strongly affected by head impact. Electrophysiological analysis shows that high frequency head impacts cause chronic modification of the AMPA/NMDA ratio in neurons that underlie the changes to cognition. To demonstrate that synaptic adaptation is caused by head impact-induced glutamate release, we pretreated mice with memantine prior to head impact. Memantine prevents the development of the key transcriptomic and electrophysiological signatures of high frequency head impact, and averts cognitive dysfunction. These data reveal synapses as a target of high frequency head impact in human and mouse brain, and that this physiological adaptation in response to head impact is sufficient to induce chronic cognitive impairment in mice.
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Beitchman JA, Lifshitz J, Harris NG, Thomas TC, Lafrenaye AD, Hånell A, Dixon CE, Povlishock JT, Rowe RK. Spatial Distribution of Neuropathology and Neuroinflammation Elucidate the Biomechanics of Fluid Percussion Injury. Neurotrauma Rep 2021; 2:59-75. [PMID: 34223546 PMCID: PMC8240834 DOI: 10.1089/neur.2020.0046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Diffuse brain injury is better described as multi-focal, where pathology can be found adjacent to seemingly uninjured neural tissue. In experimental diffuse brain injury, pathology and pathophysiology have been reported far more lateral than predicted by the impact site. We hypothesized that local thickening of the rodent skull at the temporal ridges serves to focus the intracranial mechanical forces experienced during brain injury and generate predictable pathology. We demonstrated local thickening of the skull at the temporal ridges using contour analysis on magnetic resonance imaging. After diffuse brain injury induced by midline fluid percussion injury (mFPI), pathological foci along the anterior-posterior length of cortex under the temporal ridges were evident acutely (1, 2, and 7 days) and chronically (28 days) post-injury by deposition of argyophilic reaction product. Area CA3 of the hippocampus and lateral nuclei of the thalamus showed pathological change, suggesting that mechanical forces to or from the temporal ridges shear subcortical regions. A proposed model of mFPI biomechanics suggests that injury force vectors reflect off the skull base and radiate toward the temporal ridge, thereby injuring ventral thalamus, dorsolateral hippocampus, and sensorimotor cortex. Surgically thinning the temporal ridge before injury reduced injury-induced inflammation in the sensorimotor cortex. These data build evidence for temporal ridges of the rodent skull to contribute to the observed pathology, whether by focusing extracranial forces to enter the cranium or intracranial forces to escape the cranium. Pre-clinical investigations can take advantage of the predicted pathology to explore injury mechanisms and treatment efficacy.
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Affiliation(s)
- Joshua A Beitchman
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Midwestern University, Glendale, Arizona, USA
| | - Jonathan Lifshitz
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Arizona State University, Tempe, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| | - Neil G Harris
- UCLA Brain Injury Research Center, Department of Neurosurgery, and Intellectual Development and Disabilities Research Center, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA
| | - Theresa Currier Thomas
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Arizona State University, Tempe, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| | | | - Anders Hånell
- Virginia Commonwealth University, Richmond, Virginia, USA.,Uppsala University Hospital, Uppsala, Sweden
| | | | | | - Rachel K Rowe
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
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8
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An update on the association between traumatic brain injury and Alzheimer's disease: Focus on Tau pathology and synaptic dysfunction. Neurosci Biobehav Rev 2020; 120:372-386. [PMID: 33171143 DOI: 10.1016/j.neubiorev.2020.10.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/09/2020] [Accepted: 10/19/2020] [Indexed: 02/06/2023]
Abstract
L.P. Li, J.W. Liang and H.J. Fu. An update on the association between traumatic brain injury and Alzheimer's disease: Focus on Tau pathology and synaptic dysfunction. NEUROSCI BIOBEHAV REVXXX-XXX,2020.-Traumatic brain injury (TBI) and Alzheimer's disease (AD) are devastating conditions that have long-term consequences on individual's cognitive functions. Although TBI has been considered a risk factor for the development of AD, the link between TBI and AD is still in debate. Aggregation of hyperphosphorylated tau and intercorrelated synaptic dysfunction, two key pathological elements in both TBI and AD, play a pivotal role in mediating neurodegeneration and cognitive deficits, providing a mechanistic link between these two diseases. In the first part of this review, we analyze the experimental literatures on tau pathology in various TBI models and review the distribution, biological features and mechanisms of tau pathology following TBI with implications in AD pathogenesis. In the second part, we review evidences of TBI-mediated structural and functional impairments in synapses, with a focus on the overlapped mechanisms underlying synaptic abnormalities in both TBI and AD. Finally, future perspectives are proposed for uncovering the complex relationship between TBI and neurodegeneration, and developing potential therapeutic avenues for alleviating cognitive deficits after TBI.
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9
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Sawant-Pokam PA, Vail TJ, Metcalf CS, Maguire JL, McKean TO, McKean NO, Brennan K. Preventing neuronal edema increases network excitability after traumatic brain injury. J Clin Invest 2020; 130:6005-6020. [PMID: 33044227 PMCID: PMC7598047 DOI: 10.1172/jci134793] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 08/06/2020] [Indexed: 12/31/2022] Open
Abstract
Edema is an important target for clinical intervention after traumatic brain injury (TBI). We used in vivo cellular resolution imaging and electrophysiological recording to examine the ionic mechanisms underlying neuronal edema and their effects on neuronal and network excitability after controlled cortical impact (CCI) in mice. Unexpectedly, we found that neuronal edema 48 hours after CCI was associated with reduced cellular and network excitability, concurrent with an increase in the expression ratio of the cation-chloride cotransporters (CCCs) NKCC1 and KCC2. Treatment with the CCC blocker bumetanide prevented neuronal swelling via a reversal in the NKCC1/KCC2 expression ratio, identifying altered chloride flux as the mechanism of neuronal edema. Importantly, bumetanide treatment was associated with increased neuronal and network excitability after injury, including increased susceptibility to spreading depolarizations (SDs) and seizures, known agents of clinical worsening after TBI. Treatment with mannitol, a first-line edema treatment in clinical practice, was also associated with increased susceptibility to SDs and seizures after CCI, showing that neuronal volume reduction, regardless of mechanism, was associated with an excitability increase. Finally, we observed an increase in excitability when neuronal edema normalized by 1 week after CCI. We conclude that neuronal swelling may exert protective effects against damaging excitability in the aftermath of TBI and that treatment of edema has the potential to reverse these effects.
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Affiliation(s)
| | | | - Cameron S. Metcalf
- Anticonvulsant Drug Development Program, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA
| | - Jamie L. Maguire
- Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | | | - K.C. Brennan
- Department of Neurology, School of Medicine, and
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10
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Abstract
Microglia dynamically interact with neurons influencing the development, structure, and function of neuronal networks. Recent studies suggest microglia may also influence neuronal activity by physically interacting with axonal domains responsible for action potential initiation and propagation. However, the nature of these microglial process interactions is not well understood. Microglial-axonal contacts are present early in development and persist through adulthood, implicating microglial interactions in the regulation of axonal integrity in both the developing and mature central nervous system. Moreover, changes in microglial-axonal contact have been described in disease states such as multiple sclerosis (MS) and traumatic brain injury (TBI). Depending on the disease state, there are increased associations with specific axonal segments. In MS, there is enhanced contact with the axon initial segment and node of Ranvier, while, in TBI, microglia alter interactions with axons at the site of injury, as well as at the axon initial segment. In this article, we review the interactions of microglial processes with axonal segments, analyzing their associations with various axonal domains and how these interactions may differ between MS and TBI. Furthermore, we discuss potential functional consequences and molecular mechanisms of these interactions and how these may differ among various types of microglial-axonal interactions.
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Affiliation(s)
- Savannah D Benusa
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Audrey D Lafrenaye
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
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11
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Fucich EA, Stielper ZF, Cancienne HL, Edwards S, Gilpin NW, Molina PE, Middleton JW. Endocannabinoid degradation inhibitors ameliorate neuronal and synaptic alterations following traumatic brain injury. J Neurophysiol 2020; 123:707-717. [PMID: 31913777 PMCID: PMC7052644 DOI: 10.1152/jn.00570.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/03/2020] [Accepted: 01/03/2020] [Indexed: 12/13/2022] Open
Abstract
Our previous work showed that lateral fluid percussion injury to the sensorimotor cortex (SMC) of anesthetized rats increased neuronal synaptic hyperexcitability in layer 5 (L5) neurons in ex vivo brain slices 10 days postinjury. Furthermore, endocannabinoid (EC) degradation inhibition via intraperitoneal JZL184 injection 30 min postinjury attenuated synaptic hyperexcitability. This study tested the hypothesis that traumatic brain injury (TBI) induces synaptic and intrinsic neuronal alterations of L5 SMC pyramidal neurons and that these alterations are significantly attenuated by in vivo post-TBI treatment with EC degradation inhibitors. We tested the effects of systemically administered EC degradation enzyme inhibitors (JZL184, MJN110, URB597, or JZL195) with differential selectivity for fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) on electrophysiological parameters in SMC neurons of TBI- and sham-treated rats 10 days post-TBI. We recorded intrinsic neuronal properties, including resting membrane voltage, input resistance, spike threshold, spiking responses to current input, voltage "sag" (rebound response to hyperpolarization-activated inward current), and burst firing. We also measured the frequency and amplitude of spontaneous excitatory postsynaptic currents. We then used the aggregate parameter sets (intrinsic + synaptic properties) to apply a machine learning classification algorithm to quantitatively compare neural population responses from each experimental group. Collectively, our electrophysiological and computational results indicate that sham neurons are the most distinguishable from TBI neurons. Administration of EC degradation inhibitors post-TBI exerted varying degrees of rescue, approximating the neuronal phenotype of sham neurons, with neurons from TBI/JZL195 (a dual MAGL/FAAH inhibitor) being most similar to neurons from sham rats.NEW & NOTEWORTHY This study elucidates neuronal properties altered by traumatic brain injury (TBI) in layer 5 of sensorimotor cortex, which may be implicated in post-TBI circuit dysfunction. We compared effects of systemic administration of four different endocannabinoid degradation inhibitors within a clinically relevant window postinjury. Electrophysiological measures and using a machine learning classification algorithm collectively suggest that pharmacological inhibitors targeting both monoacylglycerol lipase and fatty acid amide hydrolase (e.g., JZL195) may be most efficacious in attenuating TBI-induced neuronal dysfunction at site of injury.
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Affiliation(s)
- Elizabeth A Fucich
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Zachary F Stielper
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Heather L Cancienne
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Scott Edwards
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Nicholas W Gilpin
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Patricia E Molina
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Jason W Middleton
- Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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12
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Verley DR, Torolira D, Pulido B, Gutman B, Bragin A, Mayer A, Harris NG. Remote Changes in Cortical Excitability after Experimental Traumatic Brain Injury and Functional Reorganization. J Neurotrauma 2018; 35:2448-2461. [PMID: 29717625 DOI: 10.1089/neu.2017.5536] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Although cognitive and behavioral deficits are well known to occur following traumatic brain injury (TBI), motor deficits that occur even after mild trauma are far less known, yet are equally persistent. This study was aimed at making progress toward determining how the brain reorganizes in response to TBI. We used the adult rat controlled cortical impact injury model to study the ipsilesional forelimb map evoked by electrical stimulation of the affected limb, as well as the contralesional forelimb map evoked by stimulation of the unaffected limb, both before injury and at 1, 2, 3, and 4 weeks after using functional magnetic resonance imaging (fMRI). End-point c-FOS immunohistochemistry data following 1 h of constant stimulation of the unaffected limb were acquired in the same rats to avoid any potential confounds due to altered cerebrovascular coupling. Single and paired-pulse sensory evoked potential (SEP) data were recorded from skull electrodes over the contralesional cortex in a parallel series of rats before injury, at 3 days, and at 1, 2, 3, and 4 weeks after injury in order to determine whether alterations in cortical excitability accompanied reorganization of the cortical map. The results show a transient trans-hemispheric shift in the ipsilesional cortical map as indicated by fMRI, remote contralesional increases in cortical excitability that occur in spatially similar regions to altered fMRI activity and greater c-FOS activation, and reduced or absent ipsilesional cortical activity chronically. The contralesional changes also were indicated by reduced SEP latency within 3 days after injury, but not by blood oxygenation level-dependent fMRI until much later. Detailed interrogation of cortical excitability using paired-pulse electrophysiology showed that the contralesional cortex undergoes both an early and a late post-injury period of hyper-excitability in response to injury, interspersed by a period of relatively normal activity. From these data, we postulate a cross-hemispheric mechanism by which remote cortex excitability inhibits ipsilesional activation by rebalanced cortical excitation-inhibition.
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Affiliation(s)
- Derek R Verley
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
| | - Daniel Torolira
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
| | - Brandon Pulido
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
| | - Boris Gutman
- 2 Department of Neurology, Imaging Genetics Center, Keck/ University of Southern California School of Medicine, Institute for Neuroimaging and Informatics, University of Southern California , California
| | - Anatol Bragin
- 3 Department of Neurology, University of California , Los Angeles, California
| | - Andrew Mayer
- 4 The MIND Research Network and Department of Neurology, University of New Mexico , Albuquerque, New Mexico
| | - Neil G Harris
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
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13
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Qin Y, Han C, Che Y, Zhao J. Vibrational resonance in a randomly connected neural network. Cogn Neurodyn 2018; 12:509-518. [PMID: 30250629 DOI: 10.1007/s11571-018-9492-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/24/2018] [Accepted: 06/14/2018] [Indexed: 01/17/2023] Open
Abstract
A randomly connected network is constructed with similar characteristics (e.g., the ratio of excitatory and inhibitory neurons, the connection probability between neurons, and the axonal conduction delays) as that in the mammalian neocortex and the effects of high-frequency electrical field on the response of the network to a subthreshold low-frequency electrical field are studied in detail. It is found that both the amplitude and frequency of the high-frequency electrical field can modulate the response of the network to the low-frequency electric field. Moreover, vibrational resonance (VR) phenomenon induced by the two types of electrical fields can also be influenced by the network parameters, such as the neuron population, the connection probability between neurons and the synaptic strength. It is interesting that VR is found to be related with the ratio of excitatory neurons that are under high-frequency electrical stimuli. In summary, it is suggested that the interaction of excitatory and inhibitory currents is also an important factor that can influence the performance of VR in neural networks.
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Affiliation(s)
- Yingmei Qin
- 1Tianjin Key Laboratory of Information Sensing and Intelligent Control, School of Automation and Electrical Engineering, Tianjin University of Technology and Education, Tianjin, China
| | - Chunxiao Han
- 1Tianjin Key Laboratory of Information Sensing and Intelligent Control, School of Automation and Electrical Engineering, Tianjin University of Technology and Education, Tianjin, China
| | - Yanqiu Che
- 1Tianjin Key Laboratory of Information Sensing and Intelligent Control, School of Automation and Electrical Engineering, Tianjin University of Technology and Education, Tianjin, China
| | - Jia Zhao
- 2Key Laboratory of Cognition and Personality (Ministry of Education) and Faculty of Psychology, Southwest University, Chongqing, China.,Chongqing Collaborative Innovation Center for Brain Science, Chongqing, China
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14
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Vascak M, Jin X, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Induces Structural and Functional Disconnection of Local Neocortical Inhibitory Networks via Parvalbumin Interneuron Diffuse Axonal Injury. Cereb Cortex 2018; 28:1625-1644. [PMID: 28334184 PMCID: PMC5907353 DOI: 10.1093/cercor/bhx058] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/20/2017] [Indexed: 12/18/2022] Open
Abstract
Diffuse axonal injury (DAI) plays a major role in cortical network dysfunction posited to cause excitatory/inhibitory imbalance after mild traumatic brain injury (mTBI). Current thought holds that white matter (WM) is uniquely vulnerable to DAI. However, clinically diagnosed mTBI is not always associated with WM DAI. This suggests an undetected neocortical pathophysiology, implicating GABAergic interneurons. To evaluate this possibility, we used mild central fluid percussion injury to generate DAI in mice with Cre-driven tdTomato labeling of parvalbumin (PV) interneurons. We followed tdTomato+ profiles using confocal and electron microscopy, together with patch-clamp analysis to probe for DAI-mediated neocortical GABAergic interneuron disruption. Within 3 h post-mTBI tdTomato+ perisomatic axonal injury (PSAI) was found across somatosensory layers 2-6. The DAI marker amyloid precursor protein colocalized with GAD67 immunoreactivity within tdTomato+ PSAI, representing the majority of GABAergic interneuron DAI. At 24 h post-mTBI, we used phospho-c-Jun, a surrogate DAI marker, for retrograde assessments of sustaining somas. Via this approach, we estimated DAI occurs in ~9% of total tdTomato+ interneurons, representing ~14% of pan-neuronal DAI. Patch-clamp recordings of tdTomato+ interneurons revealed decreased inhibitory transmission. Overall, these data show that PV interneuron DAI is a consistent and significant feature of experimental mTBI with important implications for cortical network dysfunction.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - Xiaotao Jin
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
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15
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Wolf JA, Johnson BN, Johnson VE, Putt ME, Browne KD, Mietus CJ, Brown DP, Wofford KL, Smith DH, Grady MS, Cohen AS, Cullen DK. Concussion Induces Hippocampal Circuitry Disruption in Swine. J Neurotrauma 2017; 34:2303-2314. [PMID: 28298170 PMCID: PMC5510797 DOI: 10.1089/neu.2016.4848] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hippocampal-dependent deficits in learning and memory formation are a prominent feature of traumatic brain injury (TBI); however, the role of the hippocampus in cognitive dysfunction after concussion (mild TBI) is unknown. We therefore investigated functional and structural changes in the swine hippocampus following TBI using a model of head rotational acceleration that closely replicates the biomechanics and neuropathology of closed-head TBI in humans. We examined neurophysiological changes using a novel ex vivo hippocampal slice paradigm with extracellular stimulation and recording in the dentate gyrus and CA1 occurring at 7 days following non-impact inertial TBI in swine. Hippocampal neurophysiology post-injury revealed reduced axonal function, synaptic dysfunction, and regional hyperexcitability at one week following even "mild" injury levels. Moreover, these neurophysiological changes occurred in the apparent absence of intra-hippocampal neuronal or axonal degeneration. Input-output curves demonstrated an elevated excitatory post-synaptic potential (EPSP) output for a given fiber volley input in injured versus sham animals, suggesting a form of homeostatic plasticity that manifested as a compensatory response to decreased axonal function in post-synaptic regions. These data indicate that closed-head rotational acceleration-induced TBI, the common cause of concussion in humans, may induce significant alterations in hippocampal circuitry function that have not resolved at 7 days post-injury. This circuitry dysfunction may underlie some of the post-concussion symptomatology associated with the hippocampus, such as post-traumatic amnesia and ongoing cognitive deficits.
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Affiliation(s)
- John A. Wolf
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Brian N. Johnson
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Victoria E. Johnson
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mary E. Putt
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kevin D. Browne
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Constance J. Mietus
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel P. Brown
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Kathryn L. Wofford
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Douglas H. Smith
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - M. Sean Grady
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Akiva S. Cohen
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - D. Kacy Cullen
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
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16
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Vascak M, Sun J, Baer M, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Evokes Pyramidal Neuron Axon Initial Segment Plasticity and Diffuse Presynaptic Inhibitory Terminal Loss. Front Cell Neurosci 2017. [PMID: 28634442 PMCID: PMC5459898 DOI: 10.3389/fncel.2017.00157] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The axon initial segment (AIS) is the site of action potential (AP) initiation, thus a crucial regulator of neuronal activity. In excitatory pyramidal neurons, the high density of voltage-gated sodium channels (NaV1.6) at the distal AIS regulates AP initiation. A surrogate AIS marker, ankyrin-G (ankG) is a structural protein regulating neuronal functional via clustering voltage-gated ion channels. In neuronal circuits, changes in presynaptic input can alter postsynaptic output via AIS structural-functional plasticity. Recently, we showed experimental mild traumatic brain injury (mTBI) evokes neocortical circuit disruption via diffuse axonal injury (DAI) of excitatory and inhibitory neuronal systems. A key finding was that mTBI-induced neocortical electrophysiological changes involved non-DAI/ intact excitatory pyramidal neurons consistent with AIS-specific alterations. In the current study we employed Thy1-yellow fluorescent protein (YFP)-H mice to test if mTBI induces AIS structural and/or functional plasticity within intact pyramidal neurons 2 days after mTBI. We used confocal microscopy to assess intact YFP+ pyramidal neurons in layer 5 of primary somatosensory barrel field (S1BF), whose axons were continuous from the soma of origin to the subcortical white matter (SCWM). YFP+ axonal traces were superimposed on ankG and NaV1.6 immunofluorescent profiles to determine AIS position and length. We found that while mTBI had no effect on ankG start position, the length significantly decreased from the distal end, consistent with the site of AP initiation at the AIS. However, NaV1.6 structure did not change after mTBI, suggesting uncoupling from ankG. Parallel quantitative analysis of presynaptic inhibitory terminals along the postsynaptic perisomatic domain of these same intact YFP+ excitatory pyramidal neurons revealed a significant decrease in GABAergic bouton density. Also within this non-DAI population, patch-clamp recordings of intact YFP+ pyramidal neurons showed AP acceleration decreased 2 days post-mTBI, consistent with AIS functional plasticity. Simulations of realistic pyramidal neuron computational models using experimentally determined AIS lengths showed a subtle decrease is NaV1.6 density is sufficient to attenuate AP acceleration. Collectively, these findings highlight the complexity of mTBI-induced neocortical circuit disruption, involving changes in extrinsic/presynaptic inhibitory perisomatic input interfaced with intrinsic/postsynaptic intact excitatory neuron AIS output.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Jianli Sun
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Matthew Baer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
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17
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Chen W, Sheng J, Guo J, Peng G, Hong J, Li B, Chen X, Li K, Wang S. Cytokine cascades induced by mechanical trauma injury alter voltage-gated sodium channel activity in intact cortical neurons. J Neuroinflammation 2017; 14:73. [PMID: 28359334 PMCID: PMC5374609 DOI: 10.1186/s12974-017-0847-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 03/21/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) triggers both immediate (primary) and long-term (secondary) tissue damages. Secondary damages can last from hours to days or even a lifetime. Secondary damages implicate several mechanisms, including influence of inflammatory mediators, mainly cytokines, on excitability of ion channels. However, studies should further explore the effects of inflammatory cytokines on voltage-gated sodium channels (VGSCs) and excitability in distal intact neurons. METHODS Mixed cultures of mouse cortical astrocytes and neurons were subjected to mechanical injury (trauma) to mimic TBI in vitro. Expression of various cytokines in these cultures were measured by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. A trauma-conditioned medium with or without brain-derived neurotrophic factor (BDNF) was added to mouse primary cortical neurons for 6 and 24 h to mimic combined effects of multiple inflammatory cytokines on VGSCs. Spike behaviors of distal intact neurons were examined by whole-cell patch-clamp recordings. RESULTS Mechanical injury in mixed cortical neuron-astrocyte cultures significantly increased expression levels of multiple cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, monocyte chemoattractant protein-1, chemokine (C-C motif) ligand-5, IL-10, and transforming growth factor-β1, at 6 and 24 h after injury. Incubation in trauma-conditioned medium increased functional VGSCs in neuronal membranes and Na+ currents. Enhanced VGSCs were almost completely abolished by BDNF, and reinforcement of Na+ currents was also reduced in a dose-dependent manner. BDNF (30 ng/mL) also significantly reversed reduced neuronal cell viability, which was induced by medium conditioned at 6 h. At 6 and 24 h, trauma-conditioned medium significantly increased spike frequency but not spike threshold. CONCLUSIONS In TBI, the combined effect of inflammatory cytokines is directly involved in VGSC, Na+ current, and excitability dysfunction in distal intact neurons. BDNF may partly exert neuroprotective effects by maintaining balance of VGSC function in distal intact neurons.
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Affiliation(s)
- Weiqiang Chen
- Department of Neurosurgery, Fuzhou General Hospital, Xiamen University Medical College, 156 North Road, West Second Ring, Fuzhou, 350025 Fujian China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, 57 Changping Road, Shantou, 515041 Guangdong China
| | - Jiangtao Sheng
- Department of Microbiology and Immunology, Key Immunopathology Laboratory of Guangdong Province, Shantou University Medical College, 22 Xinling Road, Shantou, 515041 Guangdong China
| | - Jingfang Guo
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, 57 Changping Road, Shantou, 515041 Guangdong China
| | - Guoyi Peng
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, 57 Changping Road, Shantou, 515041 Guangdong China
| | - Jinfang Hong
- Department of Neurosurgery, Fuzhou General Hospital, Xiamen University Medical College, 156 North Road, West Second Ring, Fuzhou, 350025 Fujian China
| | - Bingbing Li
- Department of Neurosurgery, Fuzhou General Hospital, Xiamen University Medical College, 156 North Road, West Second Ring, Fuzhou, 350025 Fujian China
| | - Xiaoxuan Chen
- Department of Microbiology and Immunology, Key Immunopathology Laboratory of Guangdong Province, Shantou University Medical College, 22 Xinling Road, Shantou, 515041 Guangdong China
| | - Kangsheng Li
- Department of Microbiology and Immunology, Key Immunopathology Laboratory of Guangdong Province, Shantou University Medical College, 22 Xinling Road, Shantou, 515041 Guangdong China
| | - Shousen Wang
- Department of Neurosurgery, Fuzhou General Hospital, Xiamen University Medical College, 156 North Road, West Second Ring, Fuzhou, 350025 Fujian China
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18
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Abstract
Disorders of learning and memory have a large social and economic impact in today's society. Unfortunately, existing medical treatments have shown limited clinical efficacy or potential for modification of the disease course. Deep brain stimulation is a successful treatment for movement disorders and has shown promise in a variety of other diseases including psychiatric disorders. The authors review the potential of neuromodulation for the treatment of disorders of learning and memory. They briefly discuss learning circuitry and its involvement in Alzheimer disease and traumatic brain injury. They then review the literature supporting various targets for neuromodulation to improve memory in animals and humans. Multiple targets including entorhinal cortex, fornix, nucleus basalis of Meynert, basal ganglia, and pedunculopontine nucleus have shown a promising potential for improving dysfunctional memory by mechanisms such as altering firing patterns in neuronal networks underlying memory and increasing synaptic plasticity and neurogenesis. Significant work remains to be done to translate these findings into durable clinical therapies.
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Affiliation(s)
- Sarah K B Bick
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts
| | - Emad N Eskandar
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts
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19
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Bin Zahid A, Hubbard ME, Dammavalam VM, Balser DY, Pierre G, Kim A, Kolecki R, Mehmood T, Wall SP, Frangos SG, Huang PP, Tupper DE, Barr W, Samadani U. Assessment of acute head injury in an emergency department population using sport concussion assessment tool - 3rd edition. APPLIED NEUROPSYCHOLOGY-ADULT 2016; 25:110-119. [PMID: 27854143 DOI: 10.1080/23279095.2016.1248765] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Sport Concussion Assessment Tool version 3 (SCAT-3) is one of the most widely researched concussion assessment tools in athletes. Here normative data for SCAT3 in nonathletes are presented. The SCAT3 was administered to 98 nonathlete healthy controls, as well as 118 participants with head-injury and 46 participants with other body trauma (OI) presenting to the ED. Reference values were derived and classifier functions were built to assess the accuracy of SCAT3. The control population had a mean of 2.30 (SD = 3.62) symptoms, 4.38 (SD = 8.73) symptom severity score (SSS), and 26.02 (SD = 2.52) standardized assessment of concussion score (SAC). Participants were more likely to be diagnosed with a concussion (from among healthy controls) if the SSS > 7; or SSS ≤ 7 and SAC ≤22 (sensitivity = 96%, specificity = 77%). Identification of head injury patients from among both, healthy controls and body trauma was possible using rule SSS > 7 and headache or pressure in head present, or SSS ≤ 7 and SAC ≤ 22 (sensitivity = 87%, specificity = 80%). In this current study, the SCAT-3 provided high sensitivity to discriminate acute symptoms of TBI in the ED setting. Individuals with a SSS > 7 and headache or pressure in head, or SSS ≤ 7 but with a SAC ≤ 22 within 48-hours of an injury should undergo further testing.
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Affiliation(s)
- Abdullah Bin Zahid
- a Division of Neurosurgery , Hennepin County Medical Center , Minneapolis , Minnesota , USA.,b Division of Neurosurgery , Minneapolis VA Health Care System , Minneapolis , Minnesota , USA.,c Department of Neurosurgery , University of Minnesota , Minneapolis , Minnesota , USA
| | - Molly E Hubbard
- a Division of Neurosurgery , Hennepin County Medical Center , Minneapolis , Minnesota , USA.,c Department of Neurosurgery , University of Minnesota , Minneapolis , Minnesota , USA
| | - Vikalpa M Dammavalam
- a Division of Neurosurgery , Hennepin County Medical Center , Minneapolis , Minnesota , USA.,b Division of Neurosurgery , Minneapolis VA Health Care System , Minneapolis , Minnesota , USA
| | - David Y Balser
- a Division of Neurosurgery , Hennepin County Medical Center , Minneapolis , Minnesota , USA.,b Division of Neurosurgery , Minneapolis VA Health Care System , Minneapolis , Minnesota , USA
| | - Gritz Pierre
- d Department of Neurosurgery , New York University School of Medicine , New York , New York , USA
| | - Amie Kim
- e Department of Surgery , Westchester Medical Center , Valhallah , New York , USA
| | | | - Talha Mehmood
- e Department of Surgery , Westchester Medical Center , Valhallah , New York , USA
| | - Stephen P Wall
- g Ronald O. Perelman Department of Emergency Medicine , New York University School of Medicine , New York , New York , USA
| | - Spiros G Frangos
- h Department of Surgery , New York University School of Medicine , New York , New York , USA
| | - Paul P Huang
- d Department of Neurosurgery , New York University School of Medicine , New York , New York , USA.,i Department of Neurosurgery , Bellevue Hospital Center , New York , New York , USA
| | - David E Tupper
- j Neuropsychology Section (G8) , Hennepin County Medical Center , Minneapolis , Minnesota , USA
| | - William Barr
- k Departments of Neurology & Psychiatry , New York University School of Medicine , New York , New York , USA
| | - Uzma Samadani
- a Division of Neurosurgery , Hennepin County Medical Center , Minneapolis , Minnesota , USA.,b Division of Neurosurgery , Minneapolis VA Health Care System , Minneapolis , Minnesota , USA.,c Department of Neurosurgery , University of Minnesota , Minneapolis , Minnesota , USA
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20
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Sun J, Jacobs KM. Knockout of Cyclophilin-D Provides Partial Amelioration of Intrinsic and Synaptic Properties Altered by Mild Traumatic Brain Injury. Front Syst Neurosci 2016; 10:63. [PMID: 27489538 PMCID: PMC4951523 DOI: 10.3389/fnsys.2016.00063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 07/07/2016] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are central to cell survival and Ca2+ homeostasis due to their intracellular buffering capabilities. Mitochondrial dysfunction resulting in mitochondrial permeability transition pore (mPTP) opening has been reported after mild traumatic brain injury (mTBI). Cyclosporine A provides protection against the mPTP opening through its interaction with cyclophilin-D (CypD). A recent study has found that the extent of axonal injury after mTBI was diminished in neocortex in cyclophilin-D knockout (CypDKO) mice. Here we tested whether this CypDKO could also provide protection from the increased intrinsic and synaptic neuronal excitability previously described after mTBI in a mild central fluid percussion injury mice model. CypDKO mice were crossed with mice expressing yellow fluorescent protein (YFP) in layer V pyramidal neurons in neocortex to create CypDKO/YFP-H mice. Whole cell patch clamp recordings from axotomized (AX) and intact (IN) YFP+ layer V pyramidal neurons were made 1 and 2 days after sham or mTBI in slices from CypDKO/YFP-H mice. Both excitatory post synaptic currents (EPSCs) recorded in voltage clamp and intrinsic cellular properties, including action potential (AP), afterhyperpolarization (AHP), and depolarizing after potential (DAP) characteristics recorded in current clamp were evaluated. There was no significant difference between sham and mTBI for either spontaneous or miniature EPSC frequency, suggesting that CypDKO ameliorates excitatory synaptic abnormalities. There was a partial amelioration of intrinsic properties altered by mTBI. Alleviated were the increased slope of the AP frequency vs. injected current plot, the increased AP, AHP and DAP amplitudes. Other properties that saw a reversal that became significant in the opposite direction include the current rheobase and AP overshoot. The AP threshold remained depolarized and the input resistance remained increased in mTBI compared to sham. Additional altered properties suggest that the CypDKO likely has a direct effect on membrane properties, rather than producing a selective reduction of the effects of mTBI. These results suggest that inhibiting CypD after TBI is an effective strategy to reduce synaptic hyperexcitation, making it a continued target for potential treatment of network abnormalities.
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Affiliation(s)
- Jianli Sun
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Richmond, VA, USA
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Richmond, VA, USA
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21
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Effects of Ketamine on Neuronal Spontaneous Excitatory Postsynaptic Currents and Miniature Excitatory Postsynaptic Currents in the Somatosensory Cortex of Rats. IRANIAN JOURNAL OF MEDICAL SCIENCES 2016; 41:275-82. [PMID: 27365548 PMCID: PMC4912645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ketamine is a commonly used intravenous anesthetic which produces dissociation anesthesia, analgesia, and amnesia. The mechanism of ketamine-induced synaptic inhibition in high-level cortical areas is still unknown. We aimed to elucidate the effects of different concentrations of ketamine on the glutamatergic synaptic transmission of the neurons in the primary somatosensory cortex by using the whole-cell patch-clamp method. METHODS Sprague-Dawley rats (11-19 postnatal days, n=36) were used to obtain brain slices (300 μM). Spontaneous excitatory postsynaptic currents (data from 40 neurons) were recorded at a command potential of -70 mV in the presence of bicuculline (a competitive antagonist of GABAA receptors, 30 μM) and strychnine (glycine receptor antagonist, 30 μM). Miniature excitatory postsynaptic currents (data from 40 neurons) were also recorded when 1 μM of tetrodotoxin was added into the artificial cerebrospinal fluid. We used GraphPad Prism5for statistical analysis. Significant differences in the mean amplitude and frequency were tested using the Student paired 2-tailed t test. Values of P<0.05 were considered significant. RESULTS Different concentrations of ketamine inhibited the frequency and amplitude of the spontaneous excitatory postsynaptic currents as well as the amplitude of the miniature excitatory postsynaptic currents in a concentration-dependent manner, but they exerted no significant effect on the frequency of the miniature excitatory postsynaptic currents. CONCLUSION Ketamine inhibited the excitatory synaptic transmission of the neurons in the primary somatosensory cortex. The inhibition may have been mediated by a reduction in the sensitivity of the postsynaptic glutamatergic receptors.
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22
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Girgis F, Pace J, Sweet J, Miller JP. Hippocampal Neurophysiologic Changes after Mild Traumatic Brain Injury and Potential Neuromodulation Treatment Approaches. Front Syst Neurosci 2016; 10:8. [PMID: 26903824 PMCID: PMC4746250 DOI: 10.3389/fnsys.2016.00008] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/25/2016] [Indexed: 12/22/2022] Open
Abstract
Traumatic brain injury (TBI) is the leading cause of death and disability in individuals below age 45, and five million Americans live with chronic disability as a result. Mild TBI (mTBI), defined as TBI in the absence of major imaging or histopathological defects, is responsible for a majority of cases. Despite the lack of overt morphological defects, victims of mTBI frequently suffer lasting cognitive deficits, memory difficulties, and behavioral disturbances. There is increasing evidence that cognitive and memory dysfunction is related to subtle physiological changes that occur in the hippocampus, and these impact both the phenotype of deficits observed and subsequent recovery. Therapeutic modulation of physiological activity by means of medications commonly used for other indications or brain stimulation may represent novel treatment approaches. This review summarizes the present body of knowledge regarding neurophysiologic changes that occur in the hippocampus after mTBI, as well as potential targets for therapeutic modulation of neurologic activity.
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Affiliation(s)
- Fady Girgis
- Department of Neurosurgery, University Hospitals Case Medical Center, Case Western Reserve University Cleveland, OH, USA
| | - Jonathan Pace
- Department of Neurosurgery, University Hospitals Case Medical Center, Case Western Reserve University Cleveland, OH, USA
| | - Jennifer Sweet
- Department of Neurosurgery, University Hospitals Case Medical Center, Case Western Reserve University Cleveland, OH, USA
| | - Jonathan P Miller
- Department of Neurosurgery, University Hospitals Case Medical Center, Case Western Reserve University Cleveland, OH, USA
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