1
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Adegoke MA, Teter O, Meaney DF. Flexibility of in vitro cortical circuits influences resilience from microtrauma. Front Cell Neurosci 2022; 16:991740. [PMID: 36589287 PMCID: PMC9803265 DOI: 10.3389/fncel.2022.991740] [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: 07/11/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Background Small clusters comprising hundreds to thousands of neurons are an important level of brain architecture that correlates single neuronal properties to fulfill brain function, but the specific mechanisms through which this scaling occurs are not well understood. In this study, we developed an in vitro experimental platform of small neuronal circuits (islands) to probe the importance of structural properties for their development, physiology, and response to microtrauma. Methods Primary cortical neurons were plated on a substrate patterned to promote attachment in clusters of hundreds of cells (islands), transduced with GCaMP6f, allowed to mature until 10-13 days in vitro (DIV), and monitored with Ca2+ as a non-invasive proxy for electrical activity. We adjusted two structural factors-island size and cellular density-to evaluate their role in guiding spontaneous activity and network formation in neuronal islands. Results We found cellular density, but not island size, regulates of circuit activity and network function in this system. Low cellular density islands can achieve many states of activity, while high cellular density biases islands towards a limited regime characterized by low rates of activity and high synchronization, a property we summarized as "flexibility." The injury severity required for an island to lose activity in 50% of its population was significantly higher in low-density, high flexibility islands. Conclusion Together, these studies demonstrate flexible living cortical circuits are more resilient to microtrauma, providing the first evidence that initial circuit state may be a key factor to consider when evaluating the consequences of trauma to the cortex.
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Affiliation(s)
- Modupe A. Adegoke
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States
| | - Olivia Teter
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States
| | - David F. Meaney
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States,Department of Neurosurgery, Penn Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States,*Correspondence: David F. Meaney,
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2
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Rojvirat CP, Berlin JR, Nguyen TD. Evaluating spatial and network properties of NMDA-dependent neuronal connectivity in mixed cortical cultures. Brain Res 2022; 1787:147919. [DOI: 10.1016/j.brainres.2022.147919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 11/24/2022]
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3
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Schroeder ME, Bassett DS, Meaney DF. A multilayer network model of neuron-astrocyte populations in vitro reveals mGluR5 inhibition is protective following traumatic injury. Netw Neurosci 2022; 6:499-527. [PMID: 35733423 PMCID: PMC9208011 DOI: 10.1162/netn_a_00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 01/04/2022] [Indexed: 11/16/2022] Open
Abstract
Astrocytes communicate bidirectionally with neurons, enhancing synaptic plasticity and promoting the synchronization of neuronal microcircuits. Despite recent advances in understanding neuron-astrocyte signaling, little is known about astrocytic modulation of neuronal activity at the population level, particularly in disease or following injury. We used high-speed calcium imaging of mixed cortical cultures in vitro to determine how population activity changes after disruption of glutamatergic signaling and mechanical injury. We constructed a multilayer network model of neuron-astrocyte connectivity, which captured distinct topology and response behavior from single-cell-type networks. mGluR5 inhibition decreased neuronal activity, but did not on its own disrupt functional connectivity or network topology. In contrast, injury increased the strength, clustering, and efficiency of neuronal but not astrocytic networks, an effect that was not observed in networks pretreated with mGluR5 inhibition. Comparison of spatial and functional connectivity revealed that functional connectivity is largely independent of spatial proximity at the microscale, but mechanical injury increased the spatial-functional correlation. Finally, we found that astrocyte segments of the same cell often belong to separate functional communities based on neuronal connectivity, suggesting that astrocyte segments function as independent entities. Our findings demonstrate the utility of multilayer network models for characterizing the multiscale connectivity of two distinct but functionally dependent cell populations. Astrocytes communicate bidirectionally with neurons, enhancing synaptic plasticity and promoting the synchronization of neuronal microcircuits. We constructed a multilayer network model of neuron-astrocyte connectivity based on calcium activity in mixed cortical cultures, and used this model to evaluate the effect of glutamatergic inhibition and mechanical injury on network topology. We found that injury increased the strength, clustering, and efficiency of neuronal but not astrocytic networks, an effect that was not observed in injured networks pretreated with a glutamate receptor antagonist. Our findings demonstrate the utility of multilayer network models for characterizing the multiscale connectivity of two distinct but functionally dependent cell populations.
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Affiliation(s)
- Margaret E. Schroeder
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Danielle S. Bassett
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physics & Astronomy, College of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Department of Electrical & Systems Engineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David F. Meaney
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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4
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Shoemaker AR, Jones IE, Jeffris KD, Gabrielli G, Togliatti AG, Pichika R, Martin E, Kiskinis E, Franz CK, Finan J. Biofidelic dynamic compression of human cortical spheroids reproduces neurotrauma phenotypes. Dis Model Mech 2021; 14:273823. [PMID: 34746950 PMCID: PMC8713991 DOI: 10.1242/dmm.048916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022] Open
Abstract
Fundamental questions about patient heterogeneity and human-specific pathophysiology currently obstruct progress towards a therapy for traumatic brain injury (TBI). Human in vitro models have the potential to address these questions. 3D spheroidal cell culture protocols for human-origin neural cells have several important advantages over their 2D monolayer counterparts. Three dimensional spheroidal cultures may mature more quickly, develop more biofidelic electrophysiological activity and/or reproduce some aspects of brain architecture. Here, we present the first human in vitro model of non-penetrating TBI employing 3D spheroidal cultures. We used a custom-built device to traumatize these spheroids in a quantifiable, repeatable and biofidelic manner and correlated the heterogeneous, mechanical strain field with the injury phenotype. Trauma reduced cell viability, mitochondrial membrane potential and spontaneous, synchronous, electrophysiological activity in the spheroids. Electrophysiological deficits emerged at lower injury severities than changes in cell viability. Also, traumatized spheroids secreted lactate dehydrogenase, a marker of cell damage, and neurofilament light chain, a promising clinical biomarker of neurotrauma. These results demonstrate that 3D human in vitro models can reproduce important phenotypes of neurotrauma in vitro.
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Affiliation(s)
- Aaron R Shoemaker
- Department of Neurosurgery, NorthShore University Health System, Evanston, IL, USA
| | - Ian E Jones
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Kira D Jeffris
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Gina Gabrielli
- Department of Neurosurgery, NorthShore University Health System, Evanston, IL, USA
| | | | - Rajeswari Pichika
- Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Eric Martin
- Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Colin K Franz
- Shirley Ryan AbilityLab, Chicago, IL, USA.,Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - John Finan
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
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5
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Chang CW, Evans MD, Yu X, Yu GQ, Mucke L. Tau reduction affects excitatory and inhibitory neurons differently, reduces excitation/inhibition ratios, and counteracts network hypersynchrony. Cell Rep 2021; 37:109855. [PMID: 34686344 PMCID: PMC8648275 DOI: 10.1016/j.celrep.2021.109855] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/04/2021] [Accepted: 09/27/2021] [Indexed: 11/27/2022] Open
Abstract
The protein tau has been implicated in many brain disorders. In animal models, tau reduction suppresses epileptogenesis of diverse causes and ameliorates synaptic and behavioral abnormalities in various conditions associated with excessive excitation-inhibition (E/I) ratios. However, the underlying mechanisms are unknown. Global genetic ablation of tau in mice reduces the action potential (AP) firing and E/I ratio of pyramidal cells in acute cortical slices without affecting the excitability of these cells. Tau ablation reduces the excitatory inputs to inhibitory neurons, increases the excitability of these cells, and structurally alters their axon initial segments (AISs). In primary neuronal cultures subjected to prolonged overstimulation, tau ablation diminishes the homeostatic response of AISs in inhibitory neurons, promotes inhibition, and suppresses hypersynchrony. Together, these differential alterations in excitatory and inhibitory neurons help explain how tau reduction prevents network hypersynchrony and counteracts brain disorders causing abnormally increased E/I ratios.
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Affiliation(s)
- Che-Wei Chang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Mark D Evans
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Xinxing Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA; Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA.
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6
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Mott RE, von Reyn CR, Firestein BL, Meaney DF. Regional Neurodegeneration in vitro: The Protective Role of Neural Activity. Front Comput Neurosci 2021; 15:580107. [PMID: 33854425 PMCID: PMC8039287 DOI: 10.3389/fncom.2021.580107] [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] [Received: 07/04/2020] [Accepted: 02/11/2021] [Indexed: 12/20/2022] Open
Abstract
Traumatic brain injury is a devastating public health problem, the eighth leading cause of death across the world. To improve our understanding of how injury at the cellular scale affects neural circuit function, we developed a protocol to precisely injure individual neurons within an in vitro neural network. We used high speed calcium imaging to estimate alterations in neural activity and connectivity that occur followed targeted microtrauma. Our studies show that mechanically injured neurons inactivate following microtrauma and eventually re-integrate into the network. Single neuron re-integration is dependent on its activity prior to injury and initial connections in the network: more active and integrated neurons are more resistant to microtrauma and more likely to re-integrate into the network. Micromechanical injury leads to neuronal death 6 h post-injury in a subset of both injured and uninjured neurons. Interestingly, neural activity and network participation after injury were associated with survival in linear discriminate analysis (77.3% correct prediction, Wilks' Lambda = 0.838). Based on this observation, we modulated neuronal activity to rescue neurons after microtrauma. Inhibition of neuronal activity provided much greater survivability than did activation of neurons (ANOVA, p < 0.01 with post-hoc Tukey HSD, p < 0.01). Rescue of neurons by blocking activity in the post-acute period is partially mediated by mitochondrial energetics, as we observed silencing neurons after micromechanical injury led to a significant reduction in mitochondrial calcium accumulation. Overall, the present study provides deeper insight into the propagation of injury within networks, demonstrating that together the initial activity, network structure, and post-injury activity levels contribute to the progressive changes in a neural circuit after mechanical trauma.
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Affiliation(s)
| | - Catherine R von Reyn
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, United States.,Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - David F Meaney
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, United States
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7
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Keating CE, Browne KD, Cullen DK. Dietary manipulation of vulnerability to traumatic brain injury-induced neuronal plasma membrane permeability. Exp Neurol 2021; 340:113649. [PMID: 33600812 DOI: 10.1016/j.expneurol.2021.113649] [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] [Received: 09/14/2020] [Revised: 01/22/2021] [Accepted: 02/12/2021] [Indexed: 01/22/2023]
Abstract
Traumatic brain injury (TBI) can produce physical disruptions in the plasma membranes of neurons, referred to as mechanoporation, which lead to increased cell permeability. We suspect that such trauma-induced membrane disruptions may be influenced by the physical properties of the plasma membrane, such as elasticity or rigidity. These membrane properties are influenced by lipid composition, which can be modulated via diet, leading to the intriguing possibility of prophylactically altering diet to confer resiliency to this mechanism of acute neuronal damage in TBI. In this proof-of-concept study, we used three different diets-one high in polyunsaturated fatty acids suggested to increase elasticity (Fish Oil), one high in saturated fatty acids and cholesterol suggested to increase rigidity (High Fat), and one standard rat chow (Control)-to alter brain plasma membrane lipid composition before subjecting rats to lateral fluid percussion injury (FPI). Lipid analysis (n = 12 rats) confirmed that diets altered brain fatty acid composition after 4 weeks of feeding, with the Fish Oil diet increasing unsaturated fatty acids, and interestingly, the High Fat diet increasing omega-6 docosapentaenoic acid. One cohort of animals (n = 34 rats) was assessed immediately after FPI or sham injury for acute changes in neuronal membrane permeability in the injury-adjacent cortex. Surprisingly, sham animals fed Fish Oil had increased membrane permeability, suggesting altered passive membrane properties. In contrast, injured animals fed the High Fat diet displayed less intense uptake of permeability marker, suggesting a reduced extent of injury-induced plasma membrane disruption, although the density of affected cells matched the other diet groups. In a separate cohort survived for 7 days after FPI (n = 48 rats), animals fed the High Fat diet exhibited a reduced lesion area. At both time points there were no statistically significant differences in inflammation. Unexpectedly, these results indicate that the High Fat diet, as opposed to the Fish Oil diet, beneficially modulated acute plasma membrane permeability and resulted in a smaller lesion size at 7 days post-injury. Additional studies are necessary to determine the impact of these various diets on behavioral outcomes post-TBI. Further investigation is also needed to understand the physical properties in neuronal plasma membranes that may underlie increased resiliency to trauma-induced disruptions and, importantly, to understand how these properties may be influenced by targeted dietary modifications for vulnerable populations.
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Affiliation(s)
- Carolyn E Keating
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, 19104, USA.
| | - Kevin D Browne
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, 19104, USA.
| | - D Kacy Cullen
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, 19104, USA.
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8
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Keating CE, Cullen DK. Mechanosensation in traumatic brain injury. Neurobiol Dis 2020; 148:105210. [PMID: 33259894 DOI: 10.1016/j.nbd.2020.105210] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/10/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) is distinct from other neurological disorders because it is induced by a discrete event that applies extreme mechanical forces to the brain. This review describes how the brain senses, integrates, and responds to forces under both normal conditions and during injury. The response to forces is influenced by the unique mechanical properties of brain tissue, which differ by region, cell type, and sub-cellular structure. Elements such as the extracellular matrix, plasma membrane, transmembrane receptors, and cytoskeleton influence its properties. These same components also act as force-sensors, allowing neurons and glia to respond to their physical environment and maintain homeostasis. However, when applied forces become too large, as in TBI, these components may respond in an aberrant manner or structurally fail, resulting in unique pathological sequelae. This so-called "pathological mechanosensation" represents a spectrum of cellular responses, which vary depending on the overall biomechanical parameters of the injury and may be compounded by repetitive injuries. Such aberrant physical responses and/or damage to cells along with the resulting secondary injury cascades can ultimately lead to long-term cellular dysfunction and degeneration, often resulting in persistent deficits. Indeed, pathological mechanosensation not only directly initiates secondary injury cascades, but this post-physical damage environment provides the context in which these cascades unfold. Collectively, these points underscore the need to use experimental models that accurately replicate the biomechanics of TBI in humans. Understanding cellular responses in context with injury biomechanics may uncover therapeutic targets addressing various facets of trauma-specific sequelae.
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Affiliation(s)
- Carolyn E Keating
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, USA
| | - D Kacy Cullen
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, USA.
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9
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Keating CE, Browne KD, Duda JE, Cullen DK. Neurons in Subcortical Oculomotor Regions Are Vulnerable to Plasma Membrane Damage after Repetitive Diffuse Traumatic Brain Injury in Swine. J Neurotrauma 2020; 37:1918-1932. [PMID: 32178582 DOI: 10.1089/neu.2019.6738] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oculomotor deficits, such as insufficiencies in accommodation, convergence, and saccades, are common following traumatic brain injury (TBI). Previous studies in patients with mild TBI attributed these deficits to insufficient activation of subcortical oculomotor nuclei, although the exact mechanism is unknown. A possible cause for neuronal dysfunction in these regions is biomechanically induced plasma membrane permeability. We used our established porcine model of head rotational TBI to investigate whether cell permeability changes occurred in subcortical oculomotor areas following single or repetitive TBI, with repetitive injuries separated by 15 min, 3 days, or 7 days. Swine were subjected to sham conditions or head rotational acceleration in the sagittal plane using a HYGE pneumatic actuator. Two hours prior to the final injury, the cell-impermeant dye Lucifer Yellow was injected into the ventricles to diffuse throughout the interstitial space to assess plasmalemmal permeability. Animals were sacrificed 15 min after the final injury for immunohistological analysis. Brain regions examined for cell membrane permeability included caudate, substantia nigra pars reticulata, superior colliculus, and cranial nerve oculomotor nuclei. We found that the distribution of permeabilized neurons varied depending on the number and spacing of injuries. Repetitive injuries separated by 15 min or 3 days resulted in the most permeability. Many permeabilized cells lost neuron-specific nuclear protein reactivity, although no neuronal loss occurred acutely after injury. Microglia contacted and appeared to begin phagocytosing permeabilized neurons in repetitively injured animals. These pathologies within oculomotor areas may mediate transient dysfunction and/or degeneration that may contribute to oculomotor deficits following diffuse TBI.
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Affiliation(s)
- Carolyn E Keating
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin D Browne
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John E Duda
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - D Kacy Cullen
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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10
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Eles JR, Vazquez AL, Kozai TDY, Cui XT. In vivo imaging of neuronal calcium during electrode implantation: Spatial and temporal mapping of damage and recovery. Biomaterials 2018; 174:79-94. [PMID: 29783119 PMCID: PMC5987772 DOI: 10.1016/j.biomaterials.2018.04.043] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/16/2018] [Accepted: 04/21/2018] [Indexed: 12/13/2022]
Abstract
Implantable electrode devices enable long-term electrophysiological recordings for brain-machine interfaces and basic neuroscience research. Implantation of these devices, however, leads to neuronal damage and progressive neural degeneration that can lead to device failure. The present study uses in vivo two-photon microscopy to study the calcium activity and morphology of neurons before, during, and one month after electrode implantation to determine how implantation trauma injures neurons. We show that implantation leads to prolonged, elevated calcium levels in neurons within 150 μm of the electrode interface. These neurons show signs of mechanical distortion and mechanoporation after implantation, suggesting that calcium influx is related to mechanical trauma. Further, calcium-laden neurites develop signs of axonal injury at 1-3 h post-insert. Over the first month after implantation, physiological neuronal calcium activity increases, suggesting that neurons may be recovering. By defining the mechanisms of neuron damage after electrode implantation, our results suggest new directions for therapies to improve electrode longevity.
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Affiliation(s)
- James R Eles
- Bioengineering, University of Pittsburgh, United States; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, United States
| | - Alberto L Vazquez
- Bioengineering, University of Pittsburgh, United States; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, United States; Radiology, University of Pittsburgh, United States
| | - Takashi D Y Kozai
- Bioengineering, University of Pittsburgh, United States; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, United States; NeuroTech Center of the University of Pittsburgh Brain Institute, United States; Center for Neuroscience, University of Pittsburgh, United States
| | - X Tracy Cui
- Bioengineering, University of Pittsburgh, United States; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, United States.
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11
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Alterations in Mesoscopic Oscillations affecting Episodic Memory following Developmental Traumatic Brain Injury. Exp Neurol 2017; 300:259-273. [PMID: 29066322 DOI: 10.1016/j.expneurol.2017.10.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/27/2017] [Accepted: 10/20/2017] [Indexed: 11/20/2022]
Abstract
Certain deficits of episodic memory among young adults are the delayed consequences of an earlier mild or moderate Traumatic Brain Injury (mTBI). We examined alterations in hippocampal Local Field Oscillations (LFOs) of equivalently-impaired juvenile rodents to identify reliable functional markers of single-incidence mTBI. Two persistent, behavior-dependent, electrophysiological markers of injury were identified in the absence of external physiological symptoms by the analysis of wirelessly-transmitted hippocampal LFOs (3-80Hz) during repeat measures of the Novel Object Recognition (NOR) paradigm. Using a new method for detecting functional network activity at a single recording site, we correlated instantaneous increases in theta frequency and gamma magnitude with injury during periods of functional network organization and dissolution, presented here as Theta Epochs (TEs) and Theta Non-Epochs (TNEs), respectively. We estimated the efficacy of networks across pairs of such sites using new metrics such as the Coherence of Theta Phase (PCOH) and Inter-Epoch Intervals (IEIs) and demonstrated that behavioral deficits observed during the NOR testing stage correspond to electrophysiological deficits recorded during the preceding NOR familiarization stage. Increased theta frequency during TNEs and increased smoothness of PCOH during TEs were found to be robust markers of injury during memory-reliant behaviors.
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12
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Vogel EW, Morales FN, Meaney DF, Bass CR, Morrison B. Phosphodiesterase-4 inhibition restored hippocampal long term potentiation after primary blast. Exp Neurol 2017; 293:91-100. [PMID: 28366471 PMCID: PMC6016024 DOI: 10.1016/j.expneurol.2017.03.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/08/2017] [Accepted: 03/30/2017] [Indexed: 01/03/2023]
Abstract
Due to recent military conflicts and terrorist attacks, blast-induced traumatic brain injury (bTBI) presents a health concern for military and civilian personnel alike. Although secondary blast (penetrating injury) and tertiary blast (inertia-driven brain deformation) are known to be injurious, the effects of primary blast caused by the supersonic shock wave interacting with the skull and brain remain debated. Our group previously reported that in vitro primary blast exposure reduced long-term potentiation (LTP), the electrophysiological correlate of learning and memory, in rat organotypic hippocampal slice cultures (OHSCs) and that primary blast affects key proteins governing LTP. Recent studies have investigated phosphodiesterase-4 (PDE4) inhibition as a therapeutic strategy for reducing LTP deficits following inertia-driven TBI. We investigated the therapeutic potential of PDE4 inhibitors, specifically roflumilast, to ameliorate primary blast-induced deficits in LTP. We found that roflumilast at concentrations of 1nM or greater prevented deficits in neuronal plasticity measured 24h post-injury. We also observed a therapeutic window of at least 6h, but <23h. Additionally, we investigated molecular mechanisms that could elucidate this therapeutic effect. Roflumilast treatment (1nM delivered 6h post-injury) significantly increased total AMPA glutamate receptor 1 (GluR1) subunit expression, phosphorylation of the GluR1 subunit at the serine-831 site, and phosphorylation of stargazin at the serine-239/240 site upon LTP induction, measured 24h following injury. Roflumilast treatment significantly increased PSD-95 regardless of LTP induction. These findings indicate that further investigation into the translation of PDE4 inhibition as a therapy following bTBI is warranted.
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Affiliation(s)
- Edward W Vogel
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Fatima N Morales
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - David F Meaney
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Cameron R Bass
- Department of Biomedical Engineering, Duke University, Durham, NC 27705, USA
| | - Barclay Morrison
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA.
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13
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Ko J, Hemphill MA, Gabrieli D, Wu L, Yelleswarapu V, Lawrence G, Pennycooke W, Singh A, Meaney DF, Issadore D. Smartphone-enabled optofluidic exosome diagnostic for concussion recovery. Sci Rep 2016; 6:31215. [PMID: 27498963 PMCID: PMC4976377 DOI: 10.1038/srep31215] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 07/15/2016] [Indexed: 01/23/2023] Open
Abstract
A major impediment to improving the treatment of concussion is our current inability to identify patients that will experience persistent problems after the injury. Recently, brain-derived exosomes, which cross the blood-brain barrier and circulate following injury, have shown great potential as a noninvasive biomarker of brain recovery. However, clinical use of exosomes has been constrained by their small size (30–100 nm) and the extensive sample preparation (>24 hr) needed for traditional exosome measurements. To address these challenges, we developed a smartphone-enabled optofluidic platform to measure brain-derived exosomes. Sample-to-answer on our chip is 1 hour, 10x faster than conventional techniques. The key innovation is an optofluidic device that can detect enzyme amplified exosome biomarkers, and is read out using a smartphone camera. Using this approach, we detected and profiled GluR2+ exosomes in the post-injury state using both in vitro and murine models of concussion.
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Affiliation(s)
- Jina Ko
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Matthew A Hemphill
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - David Gabrieli
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Leon Wu
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Venkata Yelleswarapu
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Gladys Lawrence
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Wesley Pennycooke
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Anup Singh
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
| | - Dave F Meaney
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States.,Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - David Issadore
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States.,Department of Electrical and Systems Engineering, School of Engineering and Applied Sciences, University of Pennsylvania. Philadelphia, Pennsylvania, United States
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14
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Vogel EW, Effgen GB, Patel TP, Meaney DF, Bass CRD, Morrison B. Isolated Primary Blast Inhibits Long-Term Potentiation in Organotypic Hippocampal Slice Cultures. J Neurotrauma 2015; 33:652-61. [PMID: 26414012 DOI: 10.1089/neu.2015.4045] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Over the last 13 years, traumatic brain injury (TBI) has affected over 230,000 U.S. service members through the conflicts in Iraq and Afghanistan, mostly as a result of exposure to blast events. Blast-induced TBI (bTBI) is multi-phasic, with the penetrating and inertia-driven phases having been extensively studied. The effects of primary blast injury, caused by the shockwave interacting with the brain, remain unclear. Earlier in vivo studies in mice and rats have reported mixed results for primary blast effects on behavior and memory. Using a previously developed shock tube and in vitro sample receiver, we investigated the effect of isolated primary blast on the electrophysiological function of rat organotypic hippocampal slice cultures (OHSC). We found that pure primary blast exposure inhibited long-term potentiation (LTP), the electrophysiological correlate of memory, with a threshold between 9 and 39 kPa·ms impulse. This deficit occurred well below a previously identified threshold for cell death (184 kPa·ms), supporting our previously published finding that primary blast can cause changes in brain function in the absence of cell death. Other functional measures such as spontaneous activity, network synchronization, stimulus-response curves, and paired-pulse ratios (PPRs) were less affected by primary blast exposure, as compared with LTP. This is the first study to identify a tissue-level tolerance threshold for electrophysiological changes in neuronal function to isolated primary blast.
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Affiliation(s)
- Edward W Vogel
- 1 Department of Biomedical Engineering, Columbia University , New York, New York
| | - Gwen B Effgen
- 1 Department of Biomedical Engineering, Columbia University , New York, New York
| | - Tapan P Patel
- 2 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania
| | - David F Meaney
- 2 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Cameron R Dale Bass
- 3 Department of Biomedical Engineering, Duke University , Durham, North Carolina
| | - Barclay Morrison
- 1 Department of Biomedical Engineering, Columbia University , New York, New York
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15
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Eisenman LN, Emnett CM, Mohan J, Zorumski CF, Mennerick S. Quantification of bursting and synchrony in cultured hippocampal neurons. J Neurophysiol 2015; 114:1059-71. [PMID: 26041823 DOI: 10.1152/jn.00079.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/01/2015] [Indexed: 11/22/2022] Open
Abstract
It is widely appreciated that neuronal networks exhibit patterns of bursting and synchrony that are not captured by simple measures such as average spike rate. These patterns can encode information or represent pathological behavior such as seizures. However, methods for quantifying bursting and synchrony are not agreed upon and can be confounded with spike rate measures. Previous validation has largely relied on in silico networks and single experimental conditions. How published measures of bursting and synchrony perform when applied to biological networks of varied average spike rate and subjected to varied experimental challenges is unclear. In multielectrode array recordings of network activity, we found that two mechanistically distinct drugs, cyclothiazide and bicuculline, produced equivalent increases in average spike rate but differed in bursting and synchrony. We applied several measures of bursting to the recordings (2 threshold interval methods and a surprise-based method) and found that a measure based on an average critical interval, adjusted for the array-wide spike rate, performed best in quantifying differential drug effects. To quantify synchrony, we compared a coefficient of variation-based measure, the recently proposed spike time tiling coefficient, the SPIKE-distance measure, and a global synchrony index. The spike time tiling coefficient, the SPIKE-distance measure, and the global synchrony index all captured a difference between drugs with the best performance exhibited by the global synchrony index. In summary, our exploration should aid other investigators by highlighting strengths and limitations of current methods.
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Affiliation(s)
- Lawrence N Eisenman
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
| | - Christine M Emnett
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Jayaram Mohan
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri; and Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
| | - Steven Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri; and Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
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16
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Kang WH, Cao W, Graudejus O, Patel TP, Wagner S, Meaney DF, Morrison B. Alterations in Hippocampal Network Activity after In Vitro Traumatic Brain Injury. J Neurotrauma 2015; 32:1011-9. [PMID: 25517970 DOI: 10.1089/neu.2014.3667] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Traumatic brain injury (TBI) alters function and behavior, which can be characterized by changes in electrophysiological function in vitro. A common cognitive deficit after mild-to-moderate TBI is disruption of persistent working memory, of which the in vitro correlate is long-lasting, neuronal network synchronization that can be induced pharmacologically by the gamma-aminobutyric acid A antagonist, bicuculline. We utilized a novel in vitro platform for TBI research, the stretchable microelectrode array (SMEA), to investigate the effects of TBI on bicuculline-induced, long-lasting network synchronization in the hippocampus. Mechanical stimulation significantly disrupted bicuculline-induced, long-lasting network synchronization 24 h after injury, despite the continued ability of the injured neurons to fire, as revealed by a significant increase in the normalized spontaneous event rate in the dentate gyrus (DG) and CA1. A second challenge with bicuculline 24 h after the first challenge significantly decreased the normalized spontaneous event rate in the DG. In addition, we illustrate the utility of the SMEA for TBI research by combining multiple experimental paradigms in one platform, which has the potential to enable novel investigations into the mechanisms responsible for functional consequences of TBI and speed the rate of drug discovery.
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Affiliation(s)
- Woo Hyeun Kang
- 1 Department of Biomedical Engineering, Columbia University , New York, New York
| | - Wenzhe Cao
- 2 Department of Electrical Engineering, Princeton University , Princeton, New Jersey
| | - Oliver Graudejus
- 2 Department of Electrical Engineering, Princeton University , Princeton, New Jersey.,3 Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona
| | - Tapan P Patel
- 4 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Sigurd Wagner
- 2 Department of Electrical Engineering, Princeton University , Princeton, New Jersey
| | - David F Meaney
- 4 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Barclay Morrison
- 1 Department of Biomedical Engineering, Columbia University , New York, New York
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17
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Abstract
With a growing interest in how the brain responds and remodels itself following a traumatic injury, this chapter outlines the major organizing principles of how to study these injuries in the laboratory and extend these findings back into the clinic. A new repertoire of models is available to examine the response of isolated circuits of the brain in vitro, and to study precisely how mechanical forces applied to even small regions of these circuits can disrupt the entire circuit dysfunction. We review the existing knowledge garnered from these models and our current understanding of mechanically sensitive receptors and channels activated immediately following trauma. In turn, we point to the emergence of in silico models of network function that will lead to an improved understanding of the principles for the remodeling of circuit structure after traumatic, possibly pointing out new biological rules for circuit reassembly that would help guide new therapies for reconstructing brain circuits after trauma.
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Affiliation(s)
- David F Meaney
- Departments of Bioengineering and Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA.
| | - Douglas H Smith
- Departments of Bioengineering and Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
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18
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Single-neuron NMDA receptor phenotype influences neuronal rewiring and reintegration following traumatic injury. J Neurosci 2014; 34:4200-13. [PMID: 24647941 DOI: 10.1523/jneurosci.4172-13.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alterations in the activity of neural circuits are a common consequence of traumatic brain injury (TBI), but the relationship between single-neuron properties and the aggregate network behavior is not well understood. We recently reported that the GluN2B-containing NMDA receptors (NMDARs) are key in mediating mechanical forces during TBI, and that TBI produces a complex change in the functional connectivity of neuronal networks. Here, we evaluated whether cell-to-cell heterogeneity in the connectivity and aggregate contribution of GluN2B receptors to [Ca(2+)]i before injury influenced the functional rewiring, spontaneous activity, and network plasticity following injury using primary rat cortical dissociated neurons. We found that the functional connectivity of a neuron to its neighbors, combined with the relative influx of calcium through distinct NMDAR subtypes, together contributed to the individual neuronal response to trauma. Specifically, individual neurons whose [Ca(2+)]i oscillations were largely due to GluN2B NMDAR activation lost many of their functional targets 1 h following injury. In comparison, neurons with large GluN2A contribution or neurons with high functional connectivity both independently protected against injury-induced loss in connectivity. Mechanistically, we found that traumatic injury resulted in increased uncorrelated network activity, an effect linked to reduction of the voltage-sensitive Mg(2+) block of GluN2B-containing NMDARs. This uncorrelated activation of GluN2B subtypes after injury significantly limited the potential for network remodeling in response to a plasticity stimulus. Together, our data suggest that two single-cell characteristics, the aggregate contribution of NMDAR subtypes and the number of functional connections, influence network structure following traumatic injury.
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19
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Volman V, Ng LJ. Computer modeling of mild axonal injury: implications for axonal signal transmission. Neural Comput 2013; 25:2646-81. [PMID: 23777525 DOI: 10.1162/neco_a_00491] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Diffusion imaging and postmortem studies of patients with mild traumatic brain injury (mTBI) of the concussive type are consistent with the observations of diffuse axonal injury to the white matter axons. Mechanical trauma to axons affects the properties of tetrodotoxin-sensitive sodium channels at the nodes of Ranvier, leading to axonal degeneration through intra-axonal accumulation of calcium ions and activation of calcium proteases; however, the immediate implications of axonal trauma regarding axonal functionality and their relevance to transient impairment of function as observed in concussion remain elusive. A biophysically realistic computational model of a myelinated axon was developed to investigate how mTBI could immediately affect axonal function. Traumatized axons showed alterations in signal propagation properties that nonlinearly depended on the level of trauma; subthreshold traumatized axons had decreased spike propagation time, whereas suprathreshold traumatized axons exhibited a slowdown of spike propagation and spike propagation failure. Trauma had consistently reduced axonal spike amplitude. The susceptibility of an axon to trauma could be modulated by the function of an ATP-dependent sodium-potassium pump. The results suggest a mechanism by which concussive mTBI could lead to the immediate impairment of signal propagation through the axon and the emerging dysfunctional neuronal information exchange.
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Affiliation(s)
- Vladislav Volman
- L-3 Applied Technologies/Simulation, Engineering, and Testing, San Diego, CA 92121, USA.
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20
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Caeyenberghs K, Leemans A, Leunissen I, Gooijers J, Michiels K, Sunaert S, Swinnen SP. Altered structural networks and executive deficits in traumatic brain injury patients. Brain Struct Funct 2012; 219:193-209. [PMID: 23232826 DOI: 10.1007/s00429-012-0494-2] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 11/24/2012] [Indexed: 10/27/2022]
Abstract
Recent research on traumatic brain injury (TBI) has shown that impairments in cognitive and executive control functions are accompanied by a disrupted neural connectivity characterized by white matter damage. We constructed binary and weighted brain structural networks in 21 patients with chronic TBI and 17 healthy young adults utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. Executive function was assessed with the local global task and the trail making task, requiring inhibition, updating, and switching. The results revealed that TBI patients were less successful than controls on the executive tasks, as shown by the higher reaction times, higher switch costs, and lower accuracy rates. Moreover, both TBI patients and controls exhibited a small world topology in their white matter networks. More importantly, the TBI patients demonstrated increased shortest path length and decreased global efficiency of the structural network. These findings suggest that TBI patients have a weaker globally integrated structural brain network, resulting in a limited capacity to integrate information across brain regions. Furthermore, we showed that the white matter networks of both groups contained highly connected hub regions that were predominately located in the parietal cortex, frontal cortex, and basal ganglia. Finally, we showed significant correlations between switching performance and network property metrics within the TBI group. Specifically, lower scores on the switching tasks corresponded to a lower global efficiency. We conclude that analyzing the structural brain network connectivity provides new insights into understanding cognitive control changes following brain injury.
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Affiliation(s)
- K Caeyenberghs
- Movement Control and Neuroplasticity Research Group, Department of Kinesiology, Biomedical Sciences Group, K.U.Leuven, Leuven, Belgium,
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