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Wertz J, Rüttiger L, Bender B, Klose U, Stark RS, Dapper K, Saemisch J, Braun C, Singer W, Dalhoff E, Bader K, Wolpert SM, Knipper M, Munk MHJ. Differential cortical activation patterns: pioneering sub-classification of tinnitus with and without hyperacusis by combining audiometry, gamma oscillations, and hemodynamics. Front Neurosci 2024; 17:1232446. [PMID: 38239827 PMCID: PMC10794389 DOI: 10.3389/fnins.2023.1232446] [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: 05/31/2023] [Accepted: 10/16/2023] [Indexed: 01/22/2024] Open
Abstract
The ongoing controversies about the neural basis of tinnitus, whether linked with central neural gain or not, may hamper efforts to develop therapies. We asked to what extent measurable audiometric characteristics of tinnitus without (T) or with co-occurrence of hyperacusis (TH) are distinguishable on the level of cortical responses. To accomplish this, electroencephalography (EEG) and concurrent functional near-infrared spectroscopy (fNIRS) were measured while patients performed an attentionally demanding auditory discrimination task using stimuli within the individual tinnitus frequency (fTin) and a reference frequency (fRef). Resting-state-fMRI-based functional connectivity (rs-fMRI-bfc) in ascending auditory nuclei (AAN), the primary auditory cortex (AC-I), and four other regions relevant for directing attention or regulating distress in temporal, parietal, and prefrontal cortex was compiled and compared to EEG and concurrent fNIRS activity in the same brain areas. We observed no group differences in pure-tone audiometry (PTA) between 10 and 16 kHz. However, the PTA threshold around the tinnitus pitch was positively correlated with the self-rated tinnitus loudness and also correlated with distress in T-groups, while TH experienced their tinnitus loudness at minimal loudness levels already with maximal suffering scores. The T-group exhibited prolonged auditory brain stem (ABR) wave I latency and reduced ABR wave V amplitudes (indicating reduced neural synchrony in the brainstem), which were associated with lower rs-fMRI-bfc between AAN and the AC-I, as observed in previous studies. In T-subjects, these features were linked with elevated spontaneous and reduced evoked gamma oscillations and with reduced deoxygenated hemoglobin (deoxy-Hb) concentrations in response to stimulation with lower frequencies in temporal cortex (Brodmann area (BA) 41, 42, 22), implying less synchronous auditory responses during active auditory discrimination of reference frequencies. In contrast, in the TH-group gamma oscillations and hemodynamic responses in temporoparietal regions were reversed during active discrimination of tinnitus frequencies. Our findings suggest that T and TH differ in auditory discrimination and memory-dependent directed attention during active discrimination at either tinnitus or reference frequencies, offering a test paradigm that may allow for more precise sub-classification of tinnitus and future improved treatment approaches.
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Affiliation(s)
- Jakob Wertz
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Benjamin Bender
- Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Tübingen, Germany
| | - Uwe Klose
- Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Tübingen, Germany
| | - Robert S. Stark
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Konrad Dapper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Jörg Saemisch
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | | | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Katharina Bader
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Stephan M. Wolpert
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Matthias H. J. Munk
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
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2
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Fox PM, Malepati S, Manaster L, Rossignol E, Noebels JL. Developing a pathway to clinical trials for CACNA1A-related epilepsies: A patient organization perspective. THERAPEUTIC ADVANCES IN RARE DISEASE 2024; 5:26330040241245725. [PMID: 38681799 PMCID: PMC11047245 DOI: 10.1177/26330040241245725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 03/15/2024] [Indexed: 05/01/2024]
Abstract
CACNA1A-related disorders are rare neurodevelopmental disorders linked to variants in the CACNA1A gene. This gene encodes the α1 subunit of the P/Q-type calcium channel Cav2.1, which is globally expressed in the brain and crucial for fast synaptic neurotransmission. The broad spectrum of CACNA1A-related neurological disorders includes developmental and epileptic encephalopathies, familial hemiplegic migraine type 1, episodic ataxia type 2, spinocerebellar ataxia type 6, together with unclassified presentations with developmental delay, ataxia, intellectual disability, autism spectrum disorder, and language impairment. The severity of each disorder is also highly variable. The spectrum of CACNA1A-related seizures is broad across both loss-of-function and gain-of-function variants and includes absence seizures, focal seizures with altered consciousness, generalized tonic-clonic seizures, tonic seizures, status epilepticus, and infantile spasms. Furthermore, over half of CACNA1A-related epilepsies are refractory to current therapies. To date, almost 1700 CACNA1A variants have been reported in ClinVar, with over 400 listed as Pathogenic or Likely Pathogenic, but with limited-to-no clinical or functional data. Robust genotype-phenotype studies and impacts of variants on protein structure and function have also yet to be established. As a result, there are few definitive treatment options for CACNA1A-related epilepsies. The CACNA1A Foundation has set out to change the landscape of available and effective treatments and improve the quality of life for those living with CACNA1A-related disorders, including epilepsy. Established in March 2020, the Foundation has built a robust preclinical toolbox that includes patient-derived induced pluripotent stem cells and novel disease models, launched clinical trial readiness initiatives, and organized a global CACNA1A Research Network. This Research Network is currently composed of over 60 scientists and clinicians committed to collaborating to accelerate the path to CACNA1A-specific treatments and one day, a cure.
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Affiliation(s)
- Pangkong M. Fox
- CACNA1A Foundation, Inc., 31 Pt Road, Norwalk, CT 06854, USA
| | | | | | - Elsa Rossignol
- CACNA1A Foundation, Inc., Norwalk, CT, USA
- CHU Sainte-Justine Research Center, Departments of Neurosciences and Pediatrics, University of Montreal, Montreal, QC, Canada
| | - Jeffrey L. Noebels
- CACNA1A Foundation, Inc., Norwalk, CT, USA
- Blue Bird Circle Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
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3
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Lauerer RJ, Lerche H. Voltage-gated calcium channels in genetic epilepsies. J Neurochem 2023. [PMID: 37822150 DOI: 10.1111/jnc.15983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Voltage-gated calcium channels (VGCC) are abundant in the central nervous system and serve a broad spectrum of functions, either directly in cellular excitability or indirectly to regulate Ca2+ homeostasis. Ca2+ ions act as one of the main connections in excitation-transcription coupling, muscle contraction and excitation-exocytosis coupling, including synaptic transmission. In recent years, many genes encoding VGCCs main α or additional auxiliary subunits have been associated with epilepsy. This review sums up the current state of knowledge on disease mechanisms and provides guidance on disease-specific therapies where applicable.
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Affiliation(s)
- Robert J Lauerer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
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Toudji I, Toumi A, Chamberland É, Rossignol E. Interneuron odyssey: molecular mechanisms of tangential migration. Front Neural Circuits 2023; 17:1256455. [PMID: 37779671 PMCID: PMC10538647 DOI: 10.3389/fncir.2023.1256455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/21/2023] [Indexed: 10/03/2023] Open
Abstract
Cortical GABAergic interneurons are critical components of neural networks. They provide local and long-range inhibition and help coordinate network activities involved in various brain functions, including signal processing, learning, memory and adaptative responses. Disruption of cortical GABAergic interneuron migration thus induces profound deficits in neural network organization and function, and results in a variety of neurodevelopmental and neuropsychiatric disorders including epilepsy, intellectual disability, autism spectrum disorders and schizophrenia. It is thus of paramount importance to elucidate the specific mechanisms that govern the migration of interneurons to clarify some of the underlying disease mechanisms. GABAergic interneurons destined to populate the cortex arise from multipotent ventral progenitor cells located in the ganglionic eminences and pre-optic area. Post-mitotic interneurons exit their place of origin in the ventral forebrain and migrate dorsally using defined migratory streams to reach the cortical plate, which they enter through radial migration before dispersing to settle in their final laminar allocation. While migrating, cortical interneurons constantly change their morphology through the dynamic remodeling of actomyosin and microtubule cytoskeleton as they detect and integrate extracellular guidance cues generated by neuronal and non-neuronal sources distributed along their migratory routes. These processes ensure proper distribution of GABAergic interneurons across cortical areas and lamina, supporting the development of adequate network connectivity and brain function. This short review summarizes current knowledge on the cellular and molecular mechanisms controlling cortical GABAergic interneuron migration, with a focus on tangential migration, and addresses potential avenues for cell-based interneuron progenitor transplants in the treatment of neurodevelopmental disorders and epilepsy.
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Affiliation(s)
- Ikram Toudji
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Asmaa Toumi
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada
| | - Émile Chamberland
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Elsa Rossignol
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
- Department of Pediatrics, Université de Montréal, Montréal, QC, Canada
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Tkatch T, Rysevaite-Kyguoliene K, Sabeckis I, Sabeckiene D, Pauza DH, Baranauskas G. An efficient rAAV vector for protein expression in cortical parvalbumin expressing interneurons. Sci Rep 2022; 12:17851. [PMID: 36284123 PMCID: PMC9596399 DOI: 10.1038/s41598-022-21867-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 10/04/2022] [Indexed: 01/20/2023] Open
Abstract
Recombinant adeno-associated viruses (rAAV) are extensively used in both research and clinical applications. Despite significant advances, there is a lack of short promoters able to drive the expression of virus delivered genes in specific classes of neurons. We designed an efficient rAAV vector suitable for the rAAV-mediated gene expression in cortical interneurons, mainly in the parvalbumin expressing cells. The vector includes a short parvalbumin promoter and a specialized poly(A) sequence. The degree of conservation of the parvalbumin gene adjoining non-coding regions was used in both the promoter design and the selection of the poly(A) sequence. The specificity was established by co-localizing the fluorescence of the virus delivered eGFP and the antibody for a neuronal marker. rAAV particles were injected in the visual cortex area V1/V2 of adult rats (2-4 months old). Neurons expressing the virus delivered eGFP were mainly positive for interneuronal markers: 66.5 ± 2.8% for parvalbumin, 14.6 ± 2.4% for somatostatin, 7.1 ± 1.2% for vasoactive intestinal peptide, 2.8 ± 0.6% for cholecystokinin. Meanwhile, only 2.1 ± 0.5% were positive for CaMKII, a marker for principal cells in the cortex. The efficiency of the construct was verified by optogenetic experiments: the expression of the virus delivered ChR2 channels was sufficient to evoke by blue light laser high frequency bursts of action potentials in putative fast spiking neurons. We conclude that our promoter allows highly specific expression of the rAAV delivered cDNAs in cortical interneurons with a strong preference for the parvalbumin positive cells.
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Affiliation(s)
- Tatiana Tkatch
- grid.45083.3a0000 0004 0432 6841Neurophysiology Laboratory, Neuroscience Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania ,grid.16753.360000 0001 2299 3507Present Address: Department of Physiology, Northwestern University, Chicago, IL USA
| | | | - Ignas Sabeckis
- grid.45083.3a0000 0004 0432 6841Anatomy Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Deimante Sabeckiene
- grid.45083.3a0000 0004 0432 6841Anatomy Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Dainius H. Pauza
- grid.45083.3a0000 0004 0432 6841Anatomy Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Gytis Baranauskas
- grid.45083.3a0000 0004 0432 6841Neurophysiology Laboratory, Neuroscience Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania
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6
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Fish KN, Joffe ME. Targeting prefrontal cortex GABAergic microcircuits for the treatment of alcohol use disorder. Front Synaptic Neurosci 2022; 14:936911. [PMID: 36105666 PMCID: PMC9465392 DOI: 10.3389/fnsyn.2022.936911] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
Developing novel treatments for alcohol use disorders (AUDs) is of paramount importance for improving patient outcomes and alleviating the suffering related to the disease. A better understanding of the molecular and neurocircuit mechanisms through which alcohol alters brain function will be instrumental in the rational development of new efficacious treatments. Clinical studies have consistently associated the prefrontal cortex (PFC) function with symptoms of AUDs. Population-level analyses have linked the PFC structure and function with heavy drinking and/or AUD diagnosis. Thus, targeting specific PFC cell types and neural circuits holds promise for the development of new treatments. Here, we overview the tremendous diversity in the form and function of inhibitory neuron subtypes within PFC and describe their therapeutic potential. We then summarize AUD population genetics studies, clinical neurophysiology findings, and translational neuroscience discoveries. This study collectively suggests that changes in fast transmission through PFC inhibitory microcircuits are a central component of the neurobiological effects of ethanol and the core symptoms of AUDs. Finally, we submit that there is a significant and timely need to examine sex as a biological variable and human postmortem brain tissue to maximize the efforts in translating findings to new clinical treatments.
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Affiliation(s)
| | - Max E. Joffe
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
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7
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Godoy LD, Prizon T, Rossignoli MT, Leite JP, Liberato JL. Parvalbumin Role in Epilepsy and Psychiatric Comorbidities: From Mechanism to Intervention. Front Integr Neurosci 2022; 16:765324. [PMID: 35250498 PMCID: PMC8891758 DOI: 10.3389/fnint.2022.765324] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
Parvalbumin is a calcium-binding protein present in inhibitory interneurons that play an essential role in regulating many physiological processes, such as intracellular signaling and synaptic transmission. Changes in parvalbumin expression are deeply related to epilepsy, which is considered one of the most disabling neuropathologies. Epilepsy is a complex multi-factor group of disorders characterized by periods of hypersynchronous activity and hyperexcitability within brain networks. In this scenario, inhibitory neurotransmission dysfunction in modulating excitatory transmission related to the loss of subsets of parvalbumin-expressing inhibitory interneuron may have a prominent role in disrupted excitability. Some studies also reported that parvalbumin-positive interneurons altered function might contribute to psychiatric comorbidities associated with epilepsy, such as depression, anxiety, and psychosis. Understanding the epileptogenic process and comorbidities associated with epilepsy have significantly advanced through preclinical and clinical investigation. In this review, evidence from parvalbumin altered function in epilepsy and associated psychiatric comorbidities were explored with a translational perspective. Some advances in potential therapeutic interventions are highlighted, from current antiepileptic and neuroprotective drugs to cutting edge modulation of parvalbumin subpopulations using optogenetics, designer receptors exclusively activated by designer drugs (DREADD) techniques, transcranial magnetic stimulation, genome engineering, and cell grafting. Creating new perspectives on mechanisms and therapeutic strategies is valuable for understanding the pathophysiology of epilepsy and its psychiatric comorbidities and improving efficiency in clinical intervention.
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Affiliation(s)
- Lívea Dornela Godoy
- Department of Psychology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Tamiris Prizon
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Matheus Teixeira Rossignoli
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - João Pereira Leite
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- João Pereira Leite,
| | - José Luiz Liberato
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- *Correspondence: José Luiz Liberato,
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8
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Dubey M, Pascual-Garcia M, Helmes K, Wever DD, Hamada MS, Kushner SA, Kole MHP. Myelination synchronizes cortical oscillations by consolidating parvalbumin-mediated phasic inhibition. eLife 2022; 11:73827. [PMID: 35001871 PMCID: PMC8887893 DOI: 10.7554/elife.73827] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/28/2021] [Indexed: 12/18/2022] Open
Abstract
Parvalbumin-positive (PV+) γ-aminobutyric acid (GABA) interneurons are critically involved in producing rapid network oscillations and cortical microcircuit computations, but the significance of PV+ axon myelination to the temporal features of inhibition remains elusive. Here, using toxic and genetic mouse models of demyelination and dysmyelination, respectively, we find that loss of compact myelin reduces PV+ interneuron presynaptic terminals and increases failures, and the weak phasic inhibition of pyramidal neurons abolishes optogenetically driven gamma oscillations in vivo. Strikingly, during behaviors of quiet wakefulness selectively theta rhythms are amplified and accompanied by highly synchronized interictal epileptic discharges. In support of a causal role of impaired PV-mediated inhibition, optogenetic activation of myelin-deficient PV+ interneurons attenuated the power of slow theta rhythms and limited interictal spike occurrence. Thus, myelination of PV axons is required to consolidate fast inhibition of pyramidal neurons and enable behavioral state-dependent modulation of local circuit synchronization.
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Affiliation(s)
- Mohit Dubey
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | | | - Koke Helmes
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | - Dennis D Wever
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | - Mustafa S Hamada
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands.,Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Steven A Kushner
- Department of Psychiatry, Erasmus Medical Centre, Rotterdam, Netherlands
| | - Maarten H P Kole
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands.,Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
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9
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Knipper M, Singer W, Schwabe K, Hagberg GE, Li Hegner Y, Rüttiger L, Braun C, Land R. Disturbed Balance of Inhibitory Signaling Links Hearing Loss and Cognition. Front Neural Circuits 2022; 15:785603. [PMID: 35069123 PMCID: PMC8770933 DOI: 10.3389/fncir.2021.785603] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/08/2021] [Indexed: 12/19/2022] Open
Abstract
Neuronal hyperexcitability in the central auditory pathway linked to reduced inhibitory activity is associated with numerous forms of hearing loss, including noise damage, age-dependent hearing loss, and deafness, as well as tinnitus or auditory processing deficits in autism spectrum disorder (ASD). In most cases, the reduced central inhibitory activity and the accompanying hyperexcitability are interpreted as an active compensatory response to the absence of synaptic activity, linked to increased central neural gain control (increased output activity relative to reduced input). We here suggest that hyperexcitability also could be related to an immaturity or impairment of tonic inhibitory strength that typically develops in an activity-dependent process in the ascending auditory pathway with auditory experience. In these cases, high-SR auditory nerve fibers, which are critical for the shortest latencies and lowest sound thresholds, may have either not matured (possibly in congenital deafness or autism) or are dysfunctional (possibly after sudden, stressful auditory trauma or age-dependent hearing loss linked with cognitive decline). Fast auditory processing deficits can occur despite maintained basal hearing. In that case, tonic inhibitory strength is reduced in ascending auditory nuclei, and fast inhibitory parvalbumin positive interneuron (PV-IN) dendrites are diminished in auditory and frontal brain regions. This leads to deficits in central neural gain control linked to hippocampal LTP/LTD deficiencies, cognitive deficits, and unbalanced extra-hypothalamic stress control. Under these conditions, a diminished inhibitory strength may weaken local neuronal coupling to homeostatic vascular responses required for the metabolic support of auditory adjustment processes. We emphasize the need to distinguish these two states of excitatory/inhibitory imbalance in hearing disorders: (i) Under conditions of preserved fast auditory processing and sustained tonic inhibitory strength, an excitatory/inhibitory imbalance following auditory deprivation can maintain precise hearing through a memory linked, transient disinhibition that leads to enhanced spiking fidelity (central neural gain⇑) (ii) Under conditions of critically diminished fast auditory processing and reduced tonic inhibitory strength, hyperexcitability can be part of an increased synchronization over a broader frequency range, linked to reduced spiking reliability (central neural gain⇓). This latter stage mutually reinforces diminished metabolic support for auditory adjustment processes, increasing the risks for canonical dementia syndromes.
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Affiliation(s)
- Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
- *Correspondence: Marlies Knipper,
| | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Kerstin Schwabe
- Experimental Neurosurgery, Department of Neurosurgery, Hannover Medical School, Hanover, Germany
| | - Gisela E. Hagberg
- Department of Biomedical Magnetic Resonance, University Hospital Tübingen (UKT), Tübingen, Germany
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Yiwen Li Hegner
- MEG Center, University of Tübingen, Tübingen, Germany
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Christoph Braun
- MEG Center, University of Tübingen, Tübingen, Germany
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Rüdiger Land
- Department of Experimental Otology, Institute for Audioneurotechnology, Hannover Medical School, Hanover, Germany
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Reversing frontal disinhibition rescues behavioural deficits in models of CACNA1A-associated neurodevelopment disorders. Mol Psychiatry 2021; 26:7225-7246. [PMID: 34127816 DOI: 10.1038/s41380-021-01175-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/27/2021] [Accepted: 05/12/2021] [Indexed: 12/20/2022]
Abstract
CACNA1A deletions cause epilepsy, ataxia, and a range of neurocognitive deficits, including inattention, impulsivity, intellectual deficiency and autism. To investigate the underlying mechanisms, we generated mice carrying a targeted Cacna1a deletion restricted to parvalbumin-expressing (PV) neurons (PVCre;Cacna1ac/+) or to cortical pyramidal cells (PC) (Emx1Cre;Cacna1ac/+). GABA release from PV-expressing GABAergic interneurons (PV-INs) is reduced in PVCre;Cacna1ac/+ mutants, resulting in impulsivity, cognitive rigidity and inattention. By contrast, the deletion of Cacna1a in PCs does not impact cortical excitability or behaviour in Emx1Cre;Cacna1ac/+ mutants. A targeted Cacna1a deletion in the orbitofrontal cortex (OFC) results in reversal learning deficits while a medial prefrontal cortex (mPFC) deletion impairs selective attention. These deficits can be rescued by the selective chemogenetic activation of cortical PV-INs in the OFC or mPFC of PVCre;Cacna1ac/+ mutants. Thus, Cacna1a haploinsufficiency disrupts perisomatic inhibition in frontal cortical circuits, leading to a range of potentially reversible neurocognitive deficits.
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11
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Alehabib E, Esmaeilizadeh Z, Ranji-Burachaloo S, Tafakhori A, Darvish H, Movafagh A. Clinical and molecular spectrum of P/Q type calcium channel Cav2.1 in epileptic patients. Orphanet J Rare Dis 2021; 16:461. [PMID: 34727962 PMCID: PMC8562004 DOI: 10.1186/s13023-021-02101-y] [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: 01/08/2021] [Accepted: 10/24/2021] [Indexed: 11/24/2022] Open
Abstract
Background Epilepsy is a neurological disorder characterized by the potential to induce seizure and accompanied by cognitive, psychological, and social consequences. CACNA1A gene is a voltage-gated P/Q-type Cav2.1 channel that is broadly expressed in the central nervous system, and the pathogenic variants within this gene may be associated with the epileptic phenotype. In the present study, we collected clinical and molecular data related to epileptic patients with CACNA1A pathogenic variants and investigated possible meaningful relationship between age at onset, neurodevelopmental disorders, type of seizures, brain imaging abnormalities, genotype, and protein domains. Results In our retrospective literature studies, from among 890 articles reviewed, a total of 90 individuals were related to epilepsy phenotype. Our findings showed that about 90 percent of patients have shown the first symptoms in childhood and teenage years and different types of neurodevelopmental disorders, such as intellectual disability, developmental arrest, and behavioral disorders, have been common findings for these patients. Further, a wide range of abnormalities have been observed in their brain imaging, and generalized seizures have been the most type of seizures in these patients. However, our data showed no specific genotype–phenotype correlation in epileptic patients with CACNA1A pathogenic alterations. Conclusions Our study focused on epileptic phenotype in patients with CACNA1A pathogenic variants and showed a wide range of clinical and molecular heterogeneity with no specific genotype–phenotype correlation. It seems that incomplete penetrance, de-novo variants, and modifier genes are obstacles in predicting the clinical outcome. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-02101-y.
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Affiliation(s)
- Elham Alehabib
- Student Research Committee, Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Esmaeilizadeh
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sakineh Ranji-Burachaloo
- Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Abbas Tafakhori
- Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Darvish
- Neuroscience Research Center, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Abolfazl Movafagh
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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12
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Knipper M, Mazurek B, van Dijk P, Schulze H. Too Blind to See the Elephant? Why Neuroscientists Ought to Be Interested in Tinnitus. J Assoc Res Otolaryngol 2021; 22:609-621. [PMID: 34686939 PMCID: PMC8599745 DOI: 10.1007/s10162-021-00815-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/30/2021] [Indexed: 01/13/2023] Open
Abstract
A curative therapy for tinnitus currently does not exist. One may actually exist but cannot currently be causally linked to tinnitus due to the lack of consistency of concepts about the neural correlate of tinnitus. Depending on predictions, these concepts would require either a suppression or enhancement of brain activity or an increase in inhibition or disinhibition. Although procedures with a potential to silence tinnitus may exist, the lack of rationale for their curative success hampers an optimization of therapeutic protocols. We discuss here six candidate contributors to tinnitus that have been suggested by a variety of scientific experts in the field and that were addressed in a virtual panel discussion at the ARO round table in February 2021. In this discussion, several potential tinnitus contributors were considered: (i) inhibitory circuits, (ii) attention, (iii) stress, (iv) unidentified sub-entities, (v) maladaptive information transmission, and (vi) minor cochlear deafferentation. Finally, (vii) some potential therapeutic approaches were discussed. The results of this discussion is reflected here in view of potential blind spots that may still remain and that have been ignored in most tinnitus literature. We strongly suggest to consider the high impact of connecting the controversial findings to unravel the whole complexity of the tinnitus phenomenon; an essential prerequisite for establishing suitable therapeutic approaches.
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Affiliation(s)
- Marlies Knipper
- Molecular Physiology of Hearing, Tübingen Hearing Research Centre (THRC), Department of Otolaryngology, Head & Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Straße 5, 72076, Tübingen, Germany.
| | - Birgit Mazurek
- Tinnitus Center Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Pim van Dijk
- Department of Otorhinolaryngology/Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands
| | - Holger Schulze
- Experimental Otolaryngology, Friedrich-Alexander Universität Erlangen-Nürnberg, Waldstrasse 1, 91054, Erlangen, Germany
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13
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Current Pharmacologic Strategies for Treatment of Intractable Epilepsy in Children. Int Neurourol J 2021; 25:S8-18. [PMID: 34053206 PMCID: PMC8171244 DOI: 10.5213/inj.2142166.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 05/02/2021] [Indexed: 11/26/2022] Open
Abstract
Epileptic encephalopathy (EE) is a devastating pediatric disease that features medically resistant seizures, which can contribute to global developmental delays. Despite technological advancements in genetics, the neurobiological mechanisms of EEs are not fully understood, leaving few therapeutic options for affected patients. In this review, we introduce the most common EEs in pediatrics (i.e., Ohtahara syndrome, Dravet syndrome, and Lennox-Gastaut syndrome) and their molecular mechanisms that cause excitation/inhibition imbalances. We then discuss some of the essential molecules that are frequently dysregulated in EEs. Specifically, we explore voltage-gated ion channels, synaptic transmission-related proteins, and ligand-gated ion channels in association with the pathophysiology of Ohtahara syndrome, Dravet syndrome, and Lennox-Gastaut syndrome. Finally, we review currently available antiepileptic drugs used to treat seizures in patients with EEs. Since these patients often fail to achieve seizure relief even with the combination therapy, further extensive research efforts to explore the involved molecular mechanisms will be required to develop new drugs for patients with intractable epilepsy.
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14
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Panthi S, Leitch B. Chemogenetic Activation of Feed-Forward Inhibitory Parvalbumin-Expressing Interneurons in the Cortico-Thalamocortical Network During Absence Seizures. Front Cell Neurosci 2021; 15:688905. [PMID: 34122016 PMCID: PMC8193234 DOI: 10.3389/fncel.2021.688905] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022] Open
Abstract
Parvalbumin-expressing (PV+) interneurons are a subset of GABAergic inhibitory interneurons that mediate feed-forward inhibition (FFI) within the cortico-thalamocortical (CTC) network of the brain. The CTC network is a reciprocal loop with connections between cortex and thalamus. FFI PV+ interneurons control the firing of principal excitatory neurons within the CTC network and prevent runaway excitation. Studies have shown that generalized spike-wave discharges (SWDs), the hallmark of absence seizures on electroencephalogram (EEG), originate within the CTC network. In the stargazer mouse model of absence epilepsy, reduced FFI is believed to contribute to absence seizure genesis as there is a specific loss of excitatory α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) at synaptic inputs to PV+ interneurons within the CTC network. However, the degree to which this deficit is directly related to seizure generation has not yet been established. Using chemogenetics and in vivo EEG recording, we recently demonstrated that functional silencing of PV+ interneurons in either the somatosensory cortex (SScortex) or the reticular thalamic nucleus (RTN) is sufficient to generate absence-SWDs. Here, we used the same approach to assess whether activating PV+ FFI interneurons within the CTC network during absence seizures would prevent or reduce seizures. To target these interneurons, mice expressing Cre recombinase in PV+ interneurons (PV-Cre) were bred with mice expressing excitatory Gq-DREADD (hM3Dq-flox) receptors. An intraperitoneal dose of pro-epileptic chemical pentylenetetrazol (PTZ) was used to induce absence seizure. The impact of activation of FFI PV+ interneurons during seizures was tested by focal injection of the “designer drug” clozapine N-oxide (CNO) into either the SScortex or the RTN thalamus. Seizures were assessed in PVCre/Gq-DREADD animals using EEG/video recordings. Overall, DREADD-mediated activation of PV+ interneurons provided anti-epileptic effects against PTZ-induced seizures. CNO activation of FFI either prevented PTZ-induced absence seizures or suppressed their severity. Furthermore, PTZ-induced tonic-clonic seizures were also reduced in severity by activation of FFI PV+ interneurons. In contrast, administration of CNO to non-DREADD wild-type control animals did not afford any protection against PTZ-induced seizures. These data demonstrate that FFI PV+ interneurons within CTC microcircuits could be a potential therapeutic target for anti-absence seizure treatment in some patients.
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Affiliation(s)
- Sandesh Panthi
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Beulah Leitch
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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15
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Verriello L, Pauletto G, Nilo A, Lonigro I, Betto E, Valente M, Curcio F, Gigli GL. Epilepsy and episodic ataxia type 2: family study and review of the literature. J Neurol 2021; 268:4296-4302. [PMID: 33983550 DOI: 10.1007/s00415-021-10555-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Episodic ataxia type 2 (EA2) is a hereditary disorder characterized by paroxysmal attacks of ataxia, vertigo and nausea, due to mutations in the CACNA1A gene, which encodes for α1 subunit of the P/Q-type voltage-gated Ca2+ channel (CaV2.1). Other manifestations may be associated to CACNA1A mutations, such as migraine and epilepsy. The correlation between episodic ataxia and epilepsy is often underestimated and misdiagnosed. Clinical presentation of EA2 varies among patients and within the same family, and the same genetic mutation can lead to different clinical phenotypes. We herewith describe an Italian family presenting with typical EA2 and, in two of the family members (patients II.3 and III.1), epileptic seizures. The sequencing revealed a heterozygous deletion of 6 nucleotides in exon 28 of CACNA1A gene, present in all affected patients. Evidence suggests that mutations of CACNA1A, conferring a loss/reduction of CaV2.1 function, lead to an increase of thalamocortical excitation that contributes to epileptiform discharges. Our description highlights intra-family variability of EA2 phenotype and suggests that mutations in the CACNA1A gene should be suspected in individuals with focal or generalized epilepsy, associated with a family history of episodic ataxia.
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Affiliation(s)
- Lorenzo Verriello
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Piazzale Santa Maria della Misericordia 15, 33100, Udine, Italy.
| | - Giada Pauletto
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Piazzale Santa Maria della Misericordia 15, 33100, Udine, Italy
| | - Annacarmen Nilo
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Incoronata Lonigro
- Department of Medicine (DAME), University of Udine, Udine, Italy.,Department of Laboratory Medicine, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Elena Betto
- Department of Laboratory Medicine, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Mariarosaria Valente
- Department of Medicine (DAME), University of Udine, Udine, Italy.,Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Francesco Curcio
- Department of Medicine (DAME), University of Udine, Udine, Italy.,Department of Laboratory Medicine, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Gian Luigi Gigli
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.,Department of Mathematics, Informatics and Physics (DMIF), University of Udine, Udine, Italy
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16
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Song CG, Kang X, Yang F, Du WQ, Zhang JJ, Liu L, Kang JJ, Jia N, Yue H, Fan LY, Wu SX, Jiang W, Gao F. Endocannabinoid system in the neurodevelopment of GABAergic interneurons: implications for neurological and psychiatric disorders. Rev Neurosci 2021; 32:803-831. [PMID: 33781002 DOI: 10.1515/revneuro-2020-0134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 02/20/2021] [Indexed: 02/07/2023]
Abstract
In mature mammalian brains, the endocannabinoid system (ECS) plays an important role in the regulation of synaptic plasticity and the functioning of neural networks. Besides, the ECS also contributes to the neurodevelopment of the central nervous system. Due to the increase in the medical and recreational use of cannabis, it is inevitable and essential to elaborate the roles of the ECS on neurodevelopment. GABAergic interneurons represent a group of inhibitory neurons that are vital in controlling neural network activity. However, the role of the ECS in the neurodevelopment of GABAergic interneurons remains to be fully elucidated. In this review, we provide a brief introduction of the ECS and interneuron diversity. We focus on the process of interneuron development and the role of ECS in the modulation of interneuron development, from the expansion of the neural stem/progenitor cells to the migration, specification and maturation of interneurons. We further discuss the potential implications of the ECS and interneurons in the pathogenesis of neurological and psychiatric disorders, including epilepsy, schizophrenia, major depressive disorder and autism spectrum disorder.
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Affiliation(s)
- Chang-Geng Song
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China.,Department of Neurology, Xijing Hospital, Fourth Military Medical University, 127 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Xin Kang
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Fang Yang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 127 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Wan-Qing Du
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Jia-Jia Zhang
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Long Liu
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Jun-Jun Kang
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Ning Jia
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Hui Yue
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Lu-Yu Fan
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Sheng-Xi Wu
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Wen Jiang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 127 Chang Le Xi Road, Xi'an710032, Shaanxi, China
| | - Fang Gao
- Department of Neurobiology and Institute of Neurosciences, Collaborative Innovation Center for Brain Science, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an710032, Shaanxi, China
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17
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Wachsmuth L, Datunashvili M, Kemper K, Albers F, Lambers H, Lüttjohann A, Kreitz S, Budde T, Faber C. Retrosplenial Cortex Contributes to Network Changes during Seizures in the GAERS Absence Epilepsy Rat Model. Cereb Cortex Commun 2021; 2:tgab023. [PMID: 34296168 PMCID: PMC8263073 DOI: 10.1093/texcom/tgab023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 11/14/2022] Open
Abstract
Resting state-fMRI was performed to explore brain networks in Genetic Absence Epilepsy Rats from Strasbourg and in nonepileptic controls (NEC) during monitoring of the brain state by simultaneous optical Ca2+-recordings. Graph theoretical analysis allowed for the identification of acute and chronic network changes and revealed preserved small world topology before and after seizure onset. The most prominent acute change in network organization during seizures was the segregation of cortical regions from the remaining brain. Stronger connections between thalamic with limbic regions compared with preseizure state indicated network regularization during seizures. When comparing between strains, intrathalamic connections were prominent in NEC, on local level represented by higher thalamic strengths and hub scores. Subtle differences were observed for retrosplenial cortex (RS), forming more connections beyond cortex in epileptic rats, and showing a tendency to lateralization during seizures. A potential role of RS as hub between subcortical and cortical regions in epilepsy was supported by increased numbers of parvalbumin-positive (PV+) interneurons together with enhanced inhibitory synaptic activity and neuronal excitability in pyramidal neurons. By combining multimodal fMRI data, graph theoretical methods, and electrophysiological recordings, we identified the RS as promising target for modulation of seizure activity and/or comorbidities.
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Affiliation(s)
- Lydia Wachsmuth
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Maia Datunashvili
- Institute of Physiology I, University of Münster, 48149 Münster, Germany
| | - Katharina Kemper
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Franziska Albers
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Henriette Lambers
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Annika Lüttjohann
- Institute of Physiology I, University of Münster, 48149 Münster, Germany
| | - Silke Kreitz
- Experimental and Clinical Pharmacology and Toxicology, University of Erlangen, 91054 Erlangen, Germany
| | - Thomas Budde
- Institute of Physiology I, University of Münster, 48149 Münster, Germany
| | - Cornelius Faber
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
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18
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Prakash C, Mishra M, Kumar P, Kumar V, Sharma D. Response of Voltage-Gated Sodium and Calcium Channels Subtypes on Dehydroepiandrosterone Treatment in Iron-Induced Epilepsy. Cell Mol Neurobiol 2021; 41:279-292. [PMID: 32318899 DOI: 10.1007/s10571-020-00851-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/14/2020] [Indexed: 12/28/2022]
Abstract
Epilepsy is a neurological disorder characterized by the occurrence of spontaneous and recurrent seizures. In post-traumatic epilepsy (PTE), the mechanism of epileptogenesis is very complex and seems to be linked with voltage-gated ion channels. Dehydroepiandrosterone (DHEA), a neurosteroid have shown beneficial effect against various neurological disorders. We investigated antiepileptic effect of DHEA with respect to expression of voltage-gated ion channels subtypes in iron-induced epilepsy. Iron (FeCl3) solution was intracartically injected to induce epilepsy in rats and DHEA was intraperitoneally administered for 21 days. Results showed markedly increased epileptiform seizures activity along with up-regulation of Nav1.1 and Nav1.6, and down-regulation of Cav2.1α at the mRNA and protein level in the cortex and hippocampus of epileptic rats. Moreover, the study demonstrated that these channels subtypes were predominantly expressed in the neurons. DHEA treatment has countered the epileptic seizures, down-regulated Nav1.1 and Nav1.6, and up-regulated Cav2.1α without affecting their cellular localization. In conclusion, the present study demonstrates antiepileptic potential of DHEA, escorted by regulation of Nav1.1, Nav1.6, and Cav2.1α subtypes in the neurons of iron-induced epileptic rats.
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Affiliation(s)
- Chandra Prakash
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Monika Mishra
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pavan Kumar
- Department of Developmental Neurogenetics, Medical University of South Carolina, Charleston, SC, USA
| | - Vikas Kumar
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Deepak Sharma
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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19
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Lenck-Santini PP, Sakkaki S. Alterations of Neuronal Dynamics as a Mechanism for Cognitive Impairment in Epilepsy. Curr Top Behav Neurosci 2021; 55:65-106. [PMID: 33454922 DOI: 10.1007/7854_2020_193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Epilepsy is commonly associated with cognitive and behavioral deficits that dramatically affect the quality of life of patients. In order to identify novel therapeutic strategies aimed at reducing these deficits, it is critical first to understand the mechanisms leading to cognitive impairments in epilepsy. Traditionally, seizures and epileptiform activity in addition to neuronal injury have been considered to be the most significant contributors to cognitive dysfunction. In this review we however highlight the role of a new mechanism: alterations of neuronal dynamics, i.e. the timing at which neurons and networks receive and process neural information. These alterations, caused by the underlying etiologies of epilepsy syndromes, are observed in both animal models and patients in the form of abnormal oscillation patterns in unit firing, local field potentials, and electroencephalogram (EEG). Evidence suggests that such mechanisms significantly contribute to cognitive impairment in epilepsy, independently of seizures and interictal epileptiform activity. Therefore, therapeutic strategies directly targeting neuronal dynamics rather than seizure reduction may significantly benefit the quality of life of patients.
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Affiliation(s)
- Pierre-Pascal Lenck-Santini
- Aix-Marseille Université, INSERM, INMED, Marseille, France. .,Department of Neurological sciences, University of Vermont, Burlington, VT, USA.
| | - Sophie Sakkaki
- Department of Neurological sciences, University of Vermont, Burlington, VT, USA.,Université de. Montpellier, CNRS, INSERM, IGF, Montpellier, France
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20
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The Neural Bases of Tinnitus: Lessons from Deafness and Cochlear Implants. J Neurosci 2021; 40:7190-7202. [PMID: 32938634 DOI: 10.1523/jneurosci.1314-19.2020] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/05/2020] [Accepted: 08/08/2020] [Indexed: 02/06/2023] Open
Abstract
Subjective tinnitus is the conscious perception of sound in the absence of any acoustic source. The literature suggests various tinnitus mechanisms, most of which invoke changes in spontaneous firing rates of central auditory neurons resulting from modification of neural gain. Here, we present an alternative model based on evidence that tinnitus is: (1) rare in people who are congenitally deaf, (2) common in people with acquired deafness, and (3) potentially suppressed by active cochlear implants used for hearing restoration. We propose that tinnitus can only develop after fast auditory fiber activity has stimulated the synapse formation between fast-spiking parvalbumin positive (PV+) interneurons and projecting neurons in the ascending auditory path and coactivated frontostriatal networks after hearing onset. Thereafter, fast auditory fiber activity promotes feedforward and feedback inhibition mediated by PV+ interneuron activity in auditory-specific circuits. This inhibitory network enables enhanced stimulus resolution, attention-driven contrast improvement, and augmentation of auditory responses in central auditory pathways (neural gain) after damage of slow auditory fibers. When fast auditory fiber activity is lost, tonic PV+ interneuron activity is diminished, resulting in the prolonged response latencies, sudden hyperexcitability, enhanced cortical synchrony, elevated spontaneous γ oscillations, and impaired attention/stress-control that have been described in previous tinnitus models. Moreover, because fast processing is gained through sensory experience, tinnitus would not exist in congenital deafness. Electrical cochlear stimulation may have the potential to reestablish tonic inhibitory networks and thus suppress tinnitus. The proposed framework unites many ideas of tinnitus pathophysiology and may catalyze cooperative efforts to develop tinnitus therapies.
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21
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Crunelli V, Lőrincz ML, McCafferty C, Lambert RC, Leresche N, Di Giovanni G, David F. Clinical and experimental insight into pathophysiology, comorbidity and therapy of absence seizures. Brain 2020; 143:2341-2368. [PMID: 32437558 PMCID: PMC7447525 DOI: 10.1093/brain/awaa072] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/19/2019] [Accepted: 01/31/2020] [Indexed: 12/24/2022] Open
Abstract
Absence seizures in children and teenagers are generally considered relatively benign because of their non-convulsive nature and the large incidence of remittance in early adulthood. Recent studies, however, show that 30% of children with absence seizures are pharmaco-resistant and 60% are affected by severe neuropsychiatric comorbid conditions, including impairments in attention, cognition, memory and mood. In particular, attention deficits can be detected before the epilepsy diagnosis, may persist even when seizures are pharmacologically controlled and are aggravated by valproic acid monotherapy. New functional MRI-magnetoencephalography and functional MRI-EEG studies provide conclusive evidence that changes in blood oxygenation level-dependent signal amplitude and frequency in children with absence seizures can be detected in specific cortical networks at least 1 min before the start of a seizure, spike-wave discharges are not generalized at seizure onset and abnormal cortical network states remain during interictal periods. From a neurobiological perspective, recent electrical recordings and imaging of large neuronal ensembles with single-cell resolution in non-anaesthetized models show that, in contrast to the predominant opinion, cortical mechanisms, rather than an exclusively thalamic rhythmogenesis, are key in driving seizure ictogenesis and determining spike-wave frequency. Though synchronous ictal firing characterizes cortical and thalamic activity at the population level, individual cortico-thalamic and thalamocortical neurons are sparsely recruited to successive seizures and consecutive paroxysmal cycles within a seizure. New evidence strengthens previous findings on the essential role for basal ganglia networks in absence seizures, in particular the ictal increase in firing of substantia nigra GABAergic neurons. Thus, a key feature of thalamic ictogenesis is the powerful increase in the inhibition of thalamocortical neurons that originates at least from two sources, substantia nigra and thalamic reticular nucleus. This undoubtedly provides a major contribution to the ictal decrease in total firing and the ictal increase of T-type calcium channel-mediated burst firing of thalamocortical neurons, though the latter is not essential for seizure expression. Moreover, in some children and animal models with absence seizures, the ictal increase in thalamic inhibition is enhanced by the loss-of-function of the astrocytic GABA transporter GAT-1 that does not necessarily derive from a mutation in its gene. Together, these novel clinical and experimental findings bring about paradigm-shifting views of our understanding of absence seizures and demand careful choice of initial monotherapy and continuous neuropsychiatric evaluation of affected children. These issues are discussed here to focus future clinical and experimental research and help to identify novel therapeutic targets for treating both absence seizures and their comorbidities.
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Affiliation(s)
- Vincenzo Crunelli
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK
| | - Magor L Lőrincz
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK.,Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Cian McCafferty
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Régis C Lambert
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine and Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - Nathalie Leresche
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine and Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - Giuseppe Di Giovanni
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK
| | - François David
- Cerebral dynamics, learning and plasticity, Integrative Neuroscience and Cognition Center - UMR 8002, Paris, France
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22
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Elzoheiry S, Lewen A, Schneider J, Both M, Hefter D, Boffi JC, Hollnagel JO, Kann O. Mild metabolic stress is sufficient to disturb the formation of pyramidal cell ensembles during gamma oscillations. J Cereb Blood Flow Metab 2020; 40:2401-2415. [PMID: 31842665 PMCID: PMC7820691 DOI: 10.1177/0271678x19892657] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Disturbances of cognitive functions occur rapidly during acute metabolic stress. However, the underlying mechanisms are not fully understood. Cortical gamma oscillations (30-100 Hz) emerging from precise synaptic transmission between excitatory principal neurons and inhibitory interneurons, such as fast-spiking GABAergic basket cells, are associated with higher brain functions, like sensory perception, selective attention and memory formation. We investigated the alterations of cholinergic gamma oscillations at the level of neuronal ensembles in the CA3 region of rat hippocampal slice cultures. We combined electrophysiology, calcium imaging (CamKII.GCaMP6f) and mild metabolic stress that was induced by rotenone, a lipophilic and highly selective inhibitor of complex I in the respiratory chain of mitochondria. The detected pyramidal cell ensembles showing repetitive patterns of activity were highly sensitive to mild metabolic stress. Whereas such synchronised multicellular activity diminished, the overall activity of individual pyramidal cells was unaffected. Additionally, mild metabolic stress had no effect on the rate of action potential generation in fast-spiking neural units. However, the partial disinhibition of slow-spiking neural units suggests that disturbances of ensemble formation likely result from alterations in synaptic inhibition. Our study bridges disturbances on the (multi-)cellular and network level to putative cognitive impairment on the system level.
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Affiliation(s)
- Shehabeldin Elzoheiry
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Andrea Lewen
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Justus Schneider
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Martin Both
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Dimitri Hefter
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany.,RG Animal Models in Psychiatry, Clinic of Psychiatry and Psychotherapy, Central Institute of Mental Health, Mannheim, Germany
| | - Juan Carlos Boffi
- Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Jan-Oliver Hollnagel
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany.,Interdisciplinary Centre for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
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23
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Paracrine Role for Somatostatin Interneurons in the Assembly of Perisomatic Inhibitory Synapses. J Neurosci 2020; 40:7421-7435. [PMID: 32847968 DOI: 10.1523/jneurosci.0613-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/24/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
GABAergic interneurons represent a heterogenous group of cell types in neocortex that can be clustered based on developmental origin, morphology, physiology, and connectivity. Two abundant populations of cortical GABAergic interneurons include the low-threshold, somatostatin (SST)-expressing cells and the fast-spiking, parvalbumin (PV)-expressing cells. While SST+ and PV+ interneurons are both early born and migrate into the developing neocortex at similar times, SST+ cells are incorporated into functional circuits prior to PV+ cells. During this early period of neural development, SST+ cells play critical roles in the assembly and maturation of other cortical circuits; however, the mechanisms underlying this process remain poorly understood. Here, using both sexes of conditional mutant mice, we discovered that SST+ interneuron-derived Collagen XIX, a synaptogenic extracellular matrix protein, is required for the formation of GABAergic, perisomatic synapses by PV+ cells. These results, therefore, identify a paracrine mechanism by which early-born SST+ cells orchestrate inhibitory circuit formation in the developing neocortex.SIGNIFICANCE STATEMENT Inhibitory interneurons in the cerebral cortex represent a heterogenous group of cells that generate the inhibitory neurotransmitter GABA. One such interneuron type is the low-threshold, somatostatin (SST)-expressing cell, which is one of the first types of interneurons to migrate into the cerebral cortex and become incorporated into functional circuits. In addition, to contributing important roles in controlling the flow of information in the adult cerebral cortex, SST+ cells play important roles in the development of other neural circuits in the developing brain. Here, we identified an extracellular matrix protein that is released by these early-born SST+ neurons to orchestrate inhibitory circuit formation in the developing cerebral cortex.
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24
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Vormstein-Schneider D, Lin JD, Pelkey KA, Chittajallu R, Guo B, Arias-Garcia MA, Allaway K, Sakopoulos S, Schneider G, Stevenson O, Vergara J, Sharma J, Zhang Q, Franken TP, Smith J, Ibrahim LA, M Astro KJ, Sabri E, Huang S, Favuzzi E, Burbridge T, Xu Q, Guo L, Vogel I, Sanchez V, Saldi GA, Gorissen BL, Yuan X, Zaghloul KA, Devinsky O, Sabatini BL, Batista-Brito R, Reynolds J, Feng G, Fu Z, McBain CJ, Fishell G, Dimidschstein J. Viral manipulation of functionally distinct interneurons in mice, non-human primates and humans. Nat Neurosci 2020; 23:1629-1636. [PMID: 32807948 DOI: 10.1038/s41593-020-0692-9] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 07/10/2020] [Indexed: 12/21/2022]
Abstract
Recent success in identifying gene-regulatory elements in the context of recombinant adeno-associated virus vectors has enabled cell-type-restricted gene expression. However, within the cerebral cortex these tools are largely limited to broad classes of neurons. To overcome this limitation, we developed a strategy that led to the identification of multiple new enhancers to target functionally distinct neuronal subtypes. By investigating the regulatory landscape of the disease gene Scn1a, we discovered enhancers selective for parvalbumin (PV) and vasoactive intestinal peptide-expressing interneurons. Demonstrating the functional utility of these elements, we show that the PV-specific enhancer allowed for the selective targeting and manipulation of these neurons across vertebrate species, including humans. Finally, we demonstrate that our selection method is generalizable and characterizes additional PV-specific enhancers with exquisite specificity within distinct brain regions. Altogether, these viral tools can be used for cell-type-specific circuit manipulation and hold considerable promise for use in therapeutic interventions.
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Affiliation(s)
| | - Jessica D Lin
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Kenneth A Pelkey
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Ramesh Chittajallu
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Baolin Guo
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Mario A Arias-Garcia
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Kathryn Allaway
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA.,NYU Langone Medical Center, New York University, New York, NY, USA
| | - Sofia Sakopoulos
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Gates Schneider
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Olivia Stevenson
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Josselyn Vergara
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Jitendra Sharma
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Qiangge Zhang
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tom P Franken
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Jared Smith
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Leena A Ibrahim
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Kevin J M Astro
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Ehsan Sabri
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Shuhan Huang
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Emilia Favuzzi
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Timothy Burbridge
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Qing Xu
- Center for Genomics & Systems Biology, New York University, Abu Dhabi, UAE
| | - Lihua Guo
- Center for Genomics & Systems Biology, New York University, Abu Dhabi, UAE
| | - Ian Vogel
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Vanessa Sanchez
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Giuseppe A Saldi
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Bram L Gorissen
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Xiaoqing Yuan
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Kareem A Zaghloul
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY, USA
| | - Bernardo L Sabatini
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | | | - John Reynolds
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Guoping Feng
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Zhanyan Fu
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Chris J McBain
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gord Fishell
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA.
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25
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Vickers E, Osypenko D, Clark C, Okur Z, Scheiffele P, Schneggenburger R. LTP of inhibition at PV interneuron output synapses requires developmental BMP signaling. Sci Rep 2020; 10:10047. [PMID: 32572071 PMCID: PMC7308402 DOI: 10.1038/s41598-020-66862-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/27/2020] [Indexed: 11/09/2022] Open
Abstract
Parvalbumin (PV)-expressing interneurons (PV-INs) mediate well-timed inhibition of cortical principal neurons, and plasticity of these interneurons is involved in map remodeling of primary sensory cortices during critical periods of development. To assess whether bone morphogenetic protein (BMP) signaling contributes to the developmental acquisition of the synapse- and plasticity properties of PV-INs, we investigated conditional/conventional double KO mice of BMP-receptor 1a (BMPR1a; targeted to PV-INs) and 1b (BMPR1a/1b (c)DKO mice). We report that spike-timing dependent LTP at the synapse between PV-INs and principal neurons of layer 4 in the auditory cortex was absent, concomitant with a decreased paired-pulse ratio (PPR). On the other hand, baseline synaptic transmission at this connection, and action potential (AP) firing rates of PV-INs were unchanged. To explore possible gene expression targets of BMP signaling, we measured the mRNA levels of the BDNF receptor TrkB and of P/Q-type Ca2+ channel α-subunits, but did not detect expression changes of the corresponding genes in PV-INs of BMPR1a/1b (c)DKO mice. Our study suggests that BMP-signaling in PV-INs during and shortly after the critical period is necessary for the expression of LTP at PV-IN output synapses, involving gene expression programs that need to be addressed in future work.
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Affiliation(s)
- Evan Vickers
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA
| | - Denys Osypenko
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Christopher Clark
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Institute for Regenerative Medicine, University of Zürich, 8952, Schlieren, Switzerland
| | - Zeynep Okur
- Biozentrum, University of Basel, 4056, Basel, Switzerland
| | | | - Ralf Schneggenburger
- Laboratory of Synaptic Mechanisms, Brain Mind Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
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26
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Bartholome O, de la Brassinne Bonardeaux O, Neirinckx V, Rogister B. A Composite Sketch of Fast-Spiking Parvalbumin-Positive Neurons. Cereb Cortex Commun 2020; 1:tgaa026. [PMID: 34296100 PMCID: PMC8153048 DOI: 10.1093/texcom/tgaa026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/15/2020] [Accepted: 06/15/2020] [Indexed: 01/28/2023] Open
Abstract
Parvalbumin-positive neurons are inhibitory neurons that release GABA and are mostly represented by fast-spiking basket or chandelier cells. They constitute a minor neuronal population, yet their peculiar profiles allow them to react quickly to any event in the brain under normal or pathological conditions. In this review, we will summarize the current knowledge about the fundamentals of fast-spiking parvalbumin-positive neurons, focusing on their morphology and specific channel/protein content. Next, we will explore their development, maturation, and migration in the brain. Finally, we will unravel their potential contribution to the physiopathology of epilepsy.
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Affiliation(s)
| | | | | | - Bernard Rogister
- GIGA-Neurosciences, University of Liege, 4000 Liège, Belgium.,Neurology Department, CHU, Academic Hospital, University of Liege, 4000 Liège, Belgium
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27
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Gu F, Parada I, Yang T, Longo FM, Prince DA. Partial Activation of TrkB Receptors Corrects Interneuronal Calcium Channel Dysfunction and Reduces Epileptogenic Activity in Neocortex following Injury. Cereb Cortex 2020; 30:5180-5189. [PMID: 32488246 PMCID: PMC7391412 DOI: 10.1093/cercor/bhz254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 11/13/2022] Open
Abstract
Decreased GABAergic inhibition due to dysfunction of inhibitory interneurons plays an important role in post-traumatic epileptogenesis. Reduced N-current Ca2+ channel function in GABAergic terminals contributes to interneuronal abnormalities and neural circuit hyperexcitability in the partial neocortical isolation (undercut, UC) model of post-traumatic epileptogenesis. Because brain-derived neurotrophic factor (BDNF) supports the development and maintenance of interneurons, we hypothesized that the activation of BDNF tropomyosin kinase B (TrkB) receptors by a small molecule, TrkB partial agonist, PTX BD4-3 (BD), would correct N channel abnormalities and enhance inhibitory synaptic transmission in UC cortex. Immunocytochemistry (ICC) and western blots were used to quantify N- and P/Q-type channels. We recorded evoked (e)IPSCs and responses to N and P/Q channel blockers to determine the effects of BD on channel function. Field potential recordings were used to determine the effects of BD on circuit hyperexcitability. Chronic BD treatment 1) upregulated N and P/Q channel immunoreactivity in GABAergic terminals; 2) increased the effects of N or P/Q channel blockade on evoked inhibitory postsynaptic currents (eIPSCs); 3) increased GABA release probability and the frequency of sIPSCs; and 4) reduced the incidence of epileptiform discharges in UC cortex. The results suggest that chronic TrkB activation is a promising approach for rescuing injury-induced calcium channel abnormalities in inhibitory terminals, thereby improving interneuronal function and suppressing circuit hyperexcitability.
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Affiliation(s)
- Feng Gu
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305-5122, USA
| | - Isabel Parada
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305-5122, USA
| | - Tao Yang
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305-5122, USA
| | - Frank M Longo
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305-5122, USA
| | - David A Prince
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305-5122, USA
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28
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Mossner JM, Batista-Brito R, Pant R, Cardin JA. Developmental loss of MeCP2 from VIP interneurons impairs cortical function and behavior. eLife 2020; 9:55639. [PMID: 32343226 PMCID: PMC7213975 DOI: 10.7554/elife.55639] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/28/2020] [Indexed: 12/24/2022] Open
Abstract
Rett Syndrome is a devastating neurodevelopmental disorder resulting from mutations in the gene MECP2. Mutations of Mecp2 that are restricted to GABAergic cell types largely replicate the behavioral phenotypes associated with mouse models of Rett Syndrome, suggesting a pathophysiological role for inhibitory interneurons. Recent work has suggested that vasoactive intestinal peptide-expressing (VIP) interneurons may play a critical role in the proper development and function of cortical circuits, making them a potential key point of vulnerability in neurodevelopmental disorders. However, little is known about the role of VIP interneurons in Rett Syndrome. Here we find that loss of MeCP2 specifically from VIP interneurons replicates key neural and behavioral phenotypes observed following global Mecp2 loss of function.
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Affiliation(s)
- James M Mossner
- Department of Neuroscience, Yale University, New Haven, United States
| | - Renata Batista-Brito
- Department of Neuroscience, Yale University, New Haven, United States.,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, United States
| | - Rima Pant
- Department of Neuroscience, Yale University, New Haven, United States
| | - Jessica A Cardin
- Department of Neuroscience, Yale University, New Haven, United States.,Kavli Institute for Neuroscience, Yale University, New Haven, United States
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29
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Papasavvas CA, Trevelyan AJ, Kaiser M, Wang Y. Divisive gain modulation enables flexible and rapid entrainment in a neocortical microcircuit model. J Neurophysiol 2020; 123:1133-1143. [PMID: 32023140 PMCID: PMC7099485 DOI: 10.1152/jn.00401.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neocortical circuits exhibit a rich dynamic repertoire, and their ability to achieve entrainment (adjustment of their frequency to match the input frequency) is thought to support many cognitive functions and indicate functional flexibility. Although previous studies have explored the influence of various circuit properties on this phenomenon, the role of divisive gain modulation (or divisive inhibition) is unknown. This gain control mechanism is thought to be delivered mainly by the soma-targeting interneurons in neocortical microcircuits. In this study, we use a neural mass model of the neocortical microcircuit (extended Wilson-Cowan model) featuring both soma-targeting and dendrite-targeting interneuronal subpopulations to investigate the role of divisive gain modulation in entrainment. Our results demonstrate that the presence of divisive inhibition in the microcircuit, as delivered by the soma-targeting interneurons, enables its entrainment to a wider range of input frequencies. Divisive inhibition also promotes a faster entrainment, with the microcircuit needing less time to converge to the fully entrained state. We suggest that divisive inhibition, working alongside subtractive inhibition, allows for more adaptive oscillatory responses in neocortical circuits and, thus, supports healthy brain functioning.NEW & NOTEWORTHY We introduce a computational neocortical microcircuit model that features two inhibitory neural populations, with one providing subtractive and the other divisive inhibition to the excitatory population. We demonstrate that divisive inhibition widens the range of input frequencies to which the microcircuit can become entrained and diminishes the time needed to reach full entrainment. We suggest that divisive inhibition enables more adaptive oscillatory activity, with important implications for both normal and pathological brain function.
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Affiliation(s)
- Christoforos A Papasavvas
- CNNP Lab, Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom.,Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew J Trevelyan
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Marcus Kaiser
- CNNP Lab, Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom.,Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,Department of Functional Neurosurgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yujiang Wang
- CNNP Lab, Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom.,Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
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30
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Zhang L, Wen Y, Zhang Q, Chen Y, Wang J, Shi K, Du L, Bao X. CACNA1A Gene Variants in Eight Chinese Patients With a Wide Range of Phenotypes. Front Pediatr 2020; 8:577544. [PMID: 33425808 PMCID: PMC7793878 DOI: 10.3389/fped.2020.577544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/20/2020] [Indexed: 11/13/2022] Open
Abstract
Background: The CACNA1A gene encodes the voltage-dependent P/Q-type calcium channel subunit alpha-1A, which is widely expressed throughout the CNS. The biological roles of the P/Q channel are diverse and the phenotypic spectrum caused by CACNA1A mutations is wide. The aim of this study is to demonstrate its phenotypic diversity and analyze the genotype-phenotype correlations in a cohort of Chinese patients. Methods: Patients with hemiplegic migraine, cerebellar ataxia, developmental delay, or epilepsy without known causes were tested by trios whole-exome sequencing. Patients with pathogenic CACNA1A gene variants were recruited. The clinical information of the patients was collected, and the association between the genotype and the phenotype was investigated. Results: In total, eight patients (six females and two males) were found to have CACNA1A gene variants. All the variants were de novo including six missense variants and one frameshift variant. Four de novo missense variants were found in five patients located in the S4, S5, or S6 transmembrane segments of Domain II and III (p.R1352Q, p.G701V, p.A713T, p.V1393M). All of them were correlated with severe phenotypes, including three with sporadic hemiplegic migraine type 1 and epilepsy, and two with developmental and epileptic encephalopathy. The other two missense variants, p.Y62C and p.F1814L, located in the cytoplasmic side of the N-terminus and C-terminus, respectively. The variant p.Y62C was associated with severe hemiconvulsion-hemiplegia-epilepsy syndrome, and p.F1814L was associated with relatively mild phenotypes. All the missense variants were speculated as gain-of-function (GOF) mutations. The only frameshift variant, p.Q681Rfs*100, a lose-of-function (LOF) mutation, was found in a patient with episodic ataxia type 2. Meanwhile, all the patients had developmental delay ranging from mild to severe, as well as cerebellar ataxia including one with congenital ataxia, one with episodic ataxia, and six with non-progressive ataxia. Conclusions: CACNA1A variants could lead to a wide spectrum of neurological disorders including epileptic or non-epileptic paroxysmal events, cerebellar ataxia, and developmental delay. The variants could be both GOF and LOF mutations. There appeared to be some correlations between genotypes and phenotypes.
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Affiliation(s)
- Linxia Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China.,Department of Neurology, Children's Hospital of Shanxi, Taiyuan, China
| | - Yongxin Wen
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Qingping Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Yan Chen
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Jiaping Wang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Kaili Shi
- Department of Neurology, Children's Hospital of Shanxi, Taiyuan, China
| | - Lijun Du
- Department of Neurology, Children's Hospital of Shanxi, Taiyuan, China
| | - Xinhua Bao
- Department of Pediatric, Peking University First Hospital, Beijing, China
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Gawel K, Turski WA, van der Ent W, Mathai BJ, Kirstein-Smardzewska KJ, Simonsen A, Esguerra CV. Phenotypic Characterization of Larval Zebrafish (Danio rerio) with Partial Knockdown of the cacna1a Gene. Mol Neurobiol 2019; 57:1904-1916. [PMID: 31875924 PMCID: PMC7118054 DOI: 10.1007/s12035-019-01860-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/15/2019] [Indexed: 12/18/2022]
Abstract
The CACNA1A gene encodes the pore-forming α1 subunit of voltage-gated P/Q type Ca2+ channels (Cav2.1). Mutations in this gene, among others, have been described in patients and rodents suffering from absence seizures and episodic ataxia type 2 with/without concomitant seizures. In this study, we aimed for the first time to assess phenotypic and behavioral alterations in larval zebrafish with partial cacna1aa knockdown, placing special emphasis on changes in epileptiform-like electrographic discharges in larval brains. Whole-mount in situ hybridization analysis revealed expression of cacna1aa in the optic tectum and medulla oblongata of larval zebrafish at 4 and 5 days post-fertilization. Next, microinjection of two antisense morpholino oligomers (individually or in combination) targeting all splice variants of cacna1aa into fertilized zebrafish eggs resulted in dose-dependent mortality and decreased or absent touch response. Over 90% knockdown of cacna1aa on protein level induced epileptiform-like discharges in the optic tectum of larval zebrafish brains. Incubation of morphants with antiseizure drugs (sodium valproate, ethosuximide, lamotrigine, topiramate) significantly decreased the number and, in some cases, cumulative duration of epileptiform-like discharges. In this context, sodium valproate seemed to be the least effective. Carbamazepine did not affect the number and duration of epileptiform-like discharges. Altogether, our data indicate that cacna1aa loss-of-function zebrafish may be considered a new model of absence epilepsy and may prove useful both for the investigation of Cacna1a-mediated epileptogenesis and for in vivo drug screening.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.,Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | - Waldemar A Turski
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Benan J Mathai
- Faculty of Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Karolina J Kirstein-Smardzewska
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Anne Simonsen
- Faculty of Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway. .,School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Sem Sælandsvei 24, 0371, Oslo, Norway.
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Jiang X, Raju PK, D'Avanzo N, Lachance M, Pepin J, Dubeau F, Mitchell WG, Bello-Espinosa LE, Pierson TM, Minassian BA, Lacaille JC, Rossignol E. Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome. Epilepsia 2019; 60:1881-1894. [PMID: 31468518 DOI: 10.1111/epi.16316] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. METHODS We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV 2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. RESULTS We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. SIGNIFICANCE Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.
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Affiliation(s)
- Xiao Jiang
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada.,Department of Neurosciences, University of Montréal, Montreal, Canada
| | - Praveen K Raju
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada.,Department of Neurosciences, University of Montréal, Montreal, Canada
| | - Nazzareno D'Avanzo
- Department of Pharmacology and Physiology, University of Montréal, Montréal, Canada
| | - Mathieu Lachance
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada
| | - Julie Pepin
- Department of Neurosciences, University of Montréal, Montreal, Canada
| | - François Dubeau
- Department of Neurosciences, The Montreal Neurological Institute, McGill University, Montréal, Canada
| | - Wendy G Mitchell
- Neurology Division, Children's Hospital Los Angeles & Department of Neurology, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | | | - Tyler M Pierson
- Departments of Pediatrics and Neurology, The Board of Governors Regenerative Medicine Institute, Los Angeles, CA, USA
| | | | | | - Elsa Rossignol
- Sainte-Justine University Hospital Center, University of Montréal, Montréal, Canada.,Department of Neurosciences, University of Montréal, Montreal, Canada
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Schevon CA, Tobochnik S, Eissa T, Merricks E, Gill B, Parrish RR, Bateman LM, McKhann GM, Emerson RG, Trevelyan AJ. Multiscale recordings reveal the dynamic spatial structure of human seizures. Neurobiol Dis 2019; 127:303-311. [PMID: 30898669 PMCID: PMC6588430 DOI: 10.1016/j.nbd.2019.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/11/2019] [Accepted: 03/15/2019] [Indexed: 02/07/2023] Open
Abstract
The cellular activity underlying human focal seizures, and its relationship to key signatures in the EEG recordings used for therapeutic purposes, has not been well characterized despite many years of investigation both in laboratory and clinical settings. The increasing use of microelectrodes in epilepsy surgery patients has made it possible to apply principles derived from laboratory research to the problem of mapping the spatiotemporal structure of human focal seizures, and characterizing the corresponding EEG signatures. In this review, we describe results from human microelectrode studies, discuss some data interpretation pitfalls, and explain the current understanding of the key mechanisms of ictogenesis and seizure spread.
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Affiliation(s)
- Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, New York, NY, USA.
| | - Steven Tobochnik
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Tahra Eissa
- Department of Applied Mathematics, University of Colorado at Boulder, Boulder, CO, USA
| | - Edward Merricks
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Brian Gill
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - R Ryley Parrish
- Institute for Aging, Newcastle University, Newcastle-Upon-Tyne, UK
| | - Lisa M Bateman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Ronald G Emerson
- Department of Neurology, Weill Cornell Medical Center, New York, NY, USA
| | - Andrew J Trevelyan
- Department of Neurology, Columbia University Medical Center, New York, NY, USA; Institute for Aging, Newcastle University, Newcastle-Upon-Tyne, UK
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Abstract
Remodeled Cortical Inhibition Prevents Motor Seizures in Generalized Epilepsy Jiang X, Lupien-Meilleur A, Tazerart S, Lachance M, Samarova E, Araya R, Lacaille JC, Rossignol E. Ann Neurol. 2018 Sep;84(3):436-451. OBJECTIVE Deletions of CACNA1A, encoding the α1 subunit of CaV 2.1 channels, cause epilepsy with ataxia in humans. Whereas the deletion of Cacna1a in γ-aminobutyric acidergic (GABAergic) interneurons (INs) derived from the medial ganglionic eminence (MGE) impairs cortical inhibition and causes generalized seizures in Nkx2.1Cre;Cacna1ac/c mice, the targeted deletion of Cacna1a in somatostatin-expressing INs (SOM-INs), a subset of MGE-derived INs, does not result in seizures, indicating a crucial role of parvalbumin-expressing (PV) INs. Here, we identify the cellular and network consequences of Cacna1a deletion specifically in PV-INs. METHODS We generated PVCre;Cacna1ac/c mutant mice carrying a conditional Cacna1a deletion in PV neurons and evaluated the cortical cellular and network outcomes of this mutation by combining immunohistochemical assays, in vitro electrophysiology, 2-photon imaging, and in vivo video-electroencephalographic recordings. RESULTS PVCre;Cacna1ac/c mice display reduced cortical perisomatic inhibition and frequent absences, but only rare motor seizures. Compared to Nkx2.1Cre;Cacna1ac/c mice, PVCre;Cacna1ac/c mice have a net increase in cortical inhibition, with a gain of dendritic inhibition through sprouting of SOM-IN axons, largely preventing motor seizures. This beneficial compensatory remodeling of cortical GABAergic innervation is mechanistic target of rapamycin complex 1 (mTORC1)-dependent, and its inhibition with rapamycin leads to a striking increase in motor seizures. Furthermore, we show that a direct chemogenic activation of cortical SOM-INs prevents motor seizures in a model of kainate-induced seizures. INTERPRETATION Our findings provide novel evidence suggesting that the remodeling of cortical inhibition, with an mTOR-dependent gain of dendritic inhibition, determines the seizure phenotype in generalized epilepsy and that mTOR inhibition can be detrimental in epilepsies not primarily due to mTOR hyperactivation.
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Miri ML, Vinck M, Pant R, Cardin JA. Altered hippocampal interneuron activity precedes ictal onset. eLife 2018; 7:40750. [PMID: 30387711 PMCID: PMC6245730 DOI: 10.7554/elife.40750] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/02/2018] [Indexed: 12/29/2022] Open
Abstract
Although failure of GABAergic inhibition is a commonly hypothesized mechanism underlying seizure disorders, the series of events that precipitate a rapid shift from healthy to ictal activity remain unclear. Furthermore, the diversity of inhibitory interneuron populations poses a challenge for understanding local circuit interactions during seizure initiation. Using a combined optogenetic and electrophysiological approach, we examined the activity of identified mouse hippocampal interneuron classes during chemoconvulsant seizure induction in vivo. Surprisingly, synaptic inhibition from parvalbumin- (PV) and somatostatin-expressing (SST) interneurons remained intact throughout the preictal period and early ictal phase. However, these two sources of inhibition exhibited cell-type-specific differences in their preictal firing patterns and sensitivity to input. Our findings suggest that the onset of ictal activity is not associated with loss of firing by these interneurons or a failure of synaptic inhibition but is instead linked with disruptions of the respective roles these interneurons play in the hippocampal circuit.
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Affiliation(s)
- Mitra L Miri
- Department of Neuroscience, Yale University School of Medicine, New Haven, United States
| | - Martin Vinck
- Department of Neuroscience, Yale University School of Medicine, New Haven, United States
| | - Rima Pant
- Department of Neuroscience, Yale University School of Medicine, New Haven, United States
| | - Jessica A Cardin
- Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Kavli Institute for Neuroscience, Yale University, New Haven, United States
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36
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Hill JL, Jimenez DV, Mai Y, Ren M, Hallock HL, Maynard KR, Chen HY, Hardy NF, Schloesser RJ, Maher BJ, Yang F, Martinowich K. Cortistatin-expressing interneurons require TrkB signaling to suppress neural hyper-excitability. Brain Struct Funct 2018; 224:471-483. [PMID: 30377803 DOI: 10.1007/s00429-018-1783-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 10/21/2018] [Indexed: 01/12/2023]
Abstract
Signaling of brain-derived neurotrophic factor (BDNF) via tropomyosin receptor kinase B (TrkB) plays a critical role in the maturation of cortical inhibition and controls expression of inhibitory interneuron markers, including the neuropeptide cortistatin (CST). CST is expressed exclusively in a subset of cortical and hippocampal GABAergic interneurons, where it has anticonvulsant effects and controls sleep slow-wave activity (SWA). We hypothesized that CST-expressing interneurons play a critical role in regulating excitatory/inhibitory balance, and that BDNF, signaling through TrkB receptors on CST-expressing interneurons, is required for this function. Ablation of CST-expressing cells caused generalized seizures and premature death during early postnatal development, demonstrating a critical role for these cells in providing inhibition. Mice in which TrkB was selectively deleted from CST-expressing interneurons were hyperactive, slept less and developed spontaneous seizures. Frequencies of spontaneous excitatory post-synaptic currents (sEPSCs) on CST-expressing interneurons were attenuated in these mice. These data suggest that BDNF, signaling through TrkB receptors on CST-expressing cells, promotes excitatory drive onto these cells. Loss of excitatory drive onto CST-expressing cells that lack TrkB receptors may contribute to observed hyperexcitability and epileptogenesis.
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Affiliation(s)
- Julia L Hill
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Dennisse V Jimenez
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Yishan Mai
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Ming Ren
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Henry L Hallock
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Kristen R Maynard
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Huei-Ying Chen
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Nicholas F Hardy
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | | | - Brady J Maher
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA.,Departments of Psychiatry and Behavioral Sciences, and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Feng Yang
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Keri Martinowich
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA. .,Departments of Psychiatry and Behavioral Sciences, and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Cardin JA. Inhibitory Interneurons Regulate Temporal Precision and Correlations in Cortical Circuits. Trends Neurosci 2018; 41:689-700. [PMID: 30274604 PMCID: PMC6173199 DOI: 10.1016/j.tins.2018.07.015] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 01/16/2023]
Abstract
GABAergic interneurons, which are highly diverse, have long been thought to contribute to the timing of neural activity as well as to the generation and shaping of brain rhythms. GABAergic activity is crucial not only for entrainment of oscillatory activity across a neural population, but also for precise regulation of the timing of action potentials and the suppression of slow-timescale correlations. The diversity of inhibition provides the potential for flexible regulation of patterned activity, but also poses a challenge to identifying the elements of excitatory-inhibitory interactions underlying network engagement. This review highlights the key roles of inhibitory interneurons in spike correlations and brain rhythms, describes several scales on which GABAergic inhibition regulates timing in neural networks, and identifies potential consequences of inhibitory dysfunction.
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Affiliation(s)
- Jessica A Cardin
- Department of Neuroscience, Yale University, New Haven, CT 06520, USA; Kavli Institute for Neuroscience, Yale University, New Haven, CT 06520, USA.
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Voltage-Dependent Calcium Channels, Calcium Binding Proteins, and Their Interaction in the Pathological Process of Epilepsy. Int J Mol Sci 2018; 19:ijms19092735. [PMID: 30213136 PMCID: PMC6164075 DOI: 10.3390/ijms19092735] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 01/08/2023] Open
Abstract
As an important second messenger, the calcium ion (Ca2+) plays a vital role in normal brain function and in the pathophysiological process of different neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), and epilepsy. Ca2+ takes part in the regulation of neuronal excitability, and the imbalance of intracellular Ca2+ is a trigger factor for the occurrence of epilepsy. Several anti-epileptic drugs target voltage-dependent calcium channels (VDCCs). Intracellular Ca2+ levels are mainly controlled by VDCCs located in the plasma membrane, the calcium-binding proteins (CBPs) inside the cytoplasm, calcium channels located on the intracellular calcium store (particular the endoplasmic reticulum/sarcoplasmic reticulum), and the Ca2+-pumps located in the plasma membrane and intracellular calcium store. So far, while many studies have established the relationship between calcium control factors and epilepsy, the mechanism of various Ca2+ regulatory factors in epileptogenesis is still unknown. In this paper, we reviewed the function, distribution, and alteration of VDCCs and CBPs in the central nervous system in the pathological process of epilepsy. The interaction of VDCCs with CBPs in the pathological process of epilepsy was also summarized. We hope this review can provide some clues for better understanding the mechanism of epileptogenesis, and for the development of new anti-epileptic drugs targeting on VDCCs and CBPs.
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Calcium currents in striatal fast-spiking interneurons: dopaminergic modulation of Ca V1 channels. BMC Neurosci 2018; 19:42. [PMID: 30012109 PMCID: PMC6048700 DOI: 10.1186/s12868-018-0441-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/07/2018] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Striatal fast-spiking interneurons (FSI) are a subset of GABAergic cells that express calcium-binding protein parvalbumin (PV). They provide feed-forward inhibition to striatal projection neurons (SPNs), receive cortical, thalamic and dopaminergic inputs and are coupled together by electrical and chemical synapses, being important components of the striatal circuitry. It is known that dopamine (DA) depolarizes FSI via D1-class DA receptors, but no studies about the ionic mechanism of this action have been reported. Here we ask about the ion channels that are the effectors of DA actions. This work studies their Ca2+ currents. RESULTS Whole-cell recordings in acutely dissociated and identified FSI from PV-Cre transgenic mice were used to show that FSI express an array of voltage gated Ca2+ channel classes: CaV1, CaV2.1, CaV2.2, CaV2.3 and CaV3. However, CaV1 Ca2+ channel carries most of the whole-cell Ca2+ current in FSI. Activation of D1-like class of DA receptors by the D1-receptor selective agonist SKF-81297 (SKF) enhances whole-cell Ca2+ currents through CaV1 channels modulation. A previous block of CaV1 channels with nicardipine occludes the action of the DA-agonist, suggesting that no other Ca2+ channel is modulated by D1-receptor activation. Bath application of SKF in brain slices increases the firing rate and activity of FSI as measured with both whole-cell and Ca2+ imaging recordings. These actions are reduced by nicardipine. CONCLUSIONS The present work discloses one final effector of DA modulation in FSI. We conclude that the facilitatory action of DA in FSI is in part due to CaV1 Ca2+ channels positive modulation.
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Czéh B, Vardya I, Varga Z, Febbraro F, Csabai D, Martis LS, Højgaard K, Henningsen K, Bouzinova EV, Miseta A, Jensen K, Wiborg O. Long-Term Stress Disrupts the Structural and Functional Integrity of GABAergic Neuronal Networks in the Medial Prefrontal Cortex of Rats. Front Cell Neurosci 2018; 12:148. [PMID: 29973870 PMCID: PMC6020798 DOI: 10.3389/fncel.2018.00148] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 05/14/2018] [Indexed: 12/12/2022] Open
Abstract
Clinical and experimental data suggest that fronto-cortical GABAergic deficits contribute to the pathophysiology of major depressive disorder (MDD). To further test this hypothesis, we used a well characterized rat model for depression and examined the effect of stress on GABAergic neuron numbers and GABA-mediated synaptic transmission in the medial prefrontal cortex (mPFC) of rats. Adult male Wistar rats were subjected to 9-weeks of chronic mild stress (CMS) and based on their hedonic-anhedonic behavior they were behaviorally phenotyped as being stress-susceptible (anhedonic) or stress-resilient. Post mortem quantitative histopathology was used to examine the effect of stress on parvalbumin (PV)-, calretinin- (CR), calbindin- (CB), cholecystokinin- (CCK), somatostatin-(SST) and neuropeptide Y-positive (NPY+) GABAergic neuron numbers in all cortical subareas of the mPFC (anterior cingulate (Cg1), prelimbic (PrL) and infralimbic (IL) cortexes). In vitro, whole-cell patch-clamp recordings from layer II–III pyramidal neurons of the ventral mPFC was used to examine GABAergic neurotransmission. The cognitive performance of the animals was assessed in a hippocampal-prefrontal-cortical circuit dependent learning task. Stress exposure reduced the number of CCK-, CR- and PV-positive GABAergic neurons in the mPFC, most prominently in the IL cortex. Interestingly, in the stress-resilient animals, we found higher number of neuropeptide Y-positive neurons in the entire mPFC. The electrophysiological analysis revealed reduced frequencies of spontaneous and miniature IPSCs in the anhedonic rats and decreased release probability of perisomatic-targeting GABAergic synapses and alterations in GABAB receptor mediated signaling. In turn, pyramidal neurons showed higher excitability. Anhedonic rats were also significantly impaired in the object-place paired-associate learning task. These data demonstrate that long-term stress results in functional and structural deficits of prefrontal GABAergic networks. Our findings support the concept that fronto-limbic GABAergic dysfunctions may contribute to emotional and cognitive symptoms of MDD.
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Affiliation(s)
- Boldizsár Czéh
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark.,Neurobiology of Stress Research Group, János Szentágothai Research Centre & Centre for Neuroscience, Pécs, Hungary.,Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, Hungary
| | - Irina Vardya
- Synaptic Physiology Laboratory, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Zsófia Varga
- Neurobiology of Stress Research Group, János Szentágothai Research Centre & Centre for Neuroscience, Pécs, Hungary
| | - Fabia Febbraro
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Dávid Csabai
- Neurobiology of Stress Research Group, János Szentágothai Research Centre & Centre for Neuroscience, Pécs, Hungary
| | | | | | - Kim Henningsen
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Elena V Bouzinova
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Attila Miseta
- Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, Hungary
| | - Kimmo Jensen
- Synaptic Physiology Laboratory, Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ove Wiborg
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark.,Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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Activating Transcription Factor 4 (ATF4) Regulates Neuronal Activity by Controlling GABA BR Trafficking. J Neurosci 2018; 38:6102-6113. [PMID: 29875265 DOI: 10.1523/jneurosci.3350-17.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 05/29/2018] [Accepted: 05/31/2018] [Indexed: 11/21/2022] Open
Abstract
Activating Transcription Factor 4 (ATF4) has been postulated as a key regulator of learning and memory. We previously reported that specific hippocampal ATF4 downregulation causes deficits in synaptic plasticity and memory and reduction of glutamatergic functionality. Here we extend our studies to address ATF4's role in neuronal excitability. We find that long-term ATF4 knockdown in cultured rat hippocampal neurons significantly increases the frequency of spontaneous action potentials. This effect is associated with decreased functionality of metabotropic GABAB receptors (GABABRs). Knocking down ATF4 results in significant reduction of GABABR-induced GIRK currents and increased mIPSC frequency. Furthermore, reducing ATF4 significantly decreases expression of membrane-exposed, but not total, GABABR 1a and 1b subunits, indicating that ATF4 regulates GABABR trafficking. In contrast, ATF4 knockdown has no effect on surface expression of GABABR2s, several GABABR-coupled ion channels or β2 and γ2 GABAARs. Pharmacologic manipulations confirmed the relationship between GABABR functionality and action potential frequency in our cultures. Specifically, the effects of ATF4 downregulation cited above are fully rescued by transcriptionally active, but not by transcriptionally inactive, shRNA-resistant, ATF4. We previously reported that ATF4 promotes stabilization of the actin-regulatory protein Cdc42 by a transcription-dependent mechanism. To test the hypothesis that this action underlies the mechanism by which ATF4 loss affects neuronal firing rates and GABABR trafficking, we downregulated Cdc42 and found that this phenocopies the effects of ATF4 knockdown on these properties. In conclusion, our data favor a model in which ATF4, by regulating Cdc42 expression, affects trafficking of GABABRs, which in turn modulates the excitability properties of neurons.SIGNIFICANCE STATEMENT GABAB receptors (GABABRs), the metabotropic receptors for the inhibitory neurotransmitter GABA, have crucial roles in controlling the firing rate of neurons. Deficits in trafficking/functionality of GABABRs have been linked to a variety of neurological and psychiatric conditions, including epilepsy, anxiety, depression, schizophrenia, addiction, and pain. Here we show that GABABRs trafficking is influenced by Activating Transcription Factor 4 (ATF4), a protein that has a pivotal role in hippocampal memory processes. We found that ATF4 downregulation in hippocampal neurons reduces membrane-bound GABABR levels and thereby increases intrinsic excitability. These effects are mediated by loss of the small GTPase Cdc42 following ATF4 downregulation. These findings reveal a critical role for ATF4 in regulating the modulation of neuronal excitability by GABABRs.
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Bombardi C, Venzi M, Crunelli V, Di Giovanni G. Developmental changes of GABA immunoreactivity in cortico-thalamic networks of an absence seizure model. Neuropharmacology 2018; 136:56-67. [PMID: 29471054 PMCID: PMC6018618 DOI: 10.1016/j.neuropharm.2018.01.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/09/2018] [Accepted: 01/29/2018] [Indexed: 12/24/2022]
Abstract
Absence seizures (ASs) are associated with abnormalities in gamma-aminobutyric acid (GABA) neurotransmission in the thalamus and the cortex. In the present study, we used light microscopy GABA immunocytochemistry to quantify the GABA-immunoreactive (GABA-IR) neurons and neuropil in the thalamic ventral basal (VB) nucleus, the nucleus reticularis thalami (NRT), the dorsal lateral geniculate (dLGN), the primary motor cortex (M1) and perioral region of the somatosensory cortex (S1po) of genetic absence epilepsy rats from Strasbourg (GAERS). We used both the relative non-epileptic control (NEC) and normal Wistar rats as control strains, and investigated GABA immunostaining at postnatal day 15 (P15), P25, and P90. The main findings were i) an increase in GABA-IR neuropil in the VB at P25 and P90 in GAERS but not in NEC and Wistar rats; ii) an increase in NRT GABA-IR neurons in GAERS and NEC, but not Wistar, rats at both P25 and P90; and iii) an increase in GABA-IR neuron density in S1po of GAERS at P25 and P90 and in Wistar at P90. These results indicate that the increased GABAergic innervation in the VB at P25 most likely contributes to the enhanced tonic inhibition observed in GAERS prior to AS onset, whereas the lack of any anatomo-morphological GABAergic differences in GAERS S1po suggests that functional more than structural abnormalities underlie the origin of cortical paroxysms in S1po of this AS model. This article is part of the “Special Issue Dedicated to Norman G. Bowery”. GABA-IR profiles increase in P25 to P90 VB neuropil in GAERS but not in NEC and Wistar rats. NRT GABA-IR neurons increase in P25 and P90 GAERS and NEC, but not in Wistar rats. GABA-IR neuron density increases in S1po of GAERS at P25 and P90 and in Wistar at P90.
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Affiliation(s)
- Cristiano Bombardi
- University of Bologna, Department of Veterinary Medical Science, Bologna, Italy
| | - Marcello Venzi
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Department of Physiology and Biochemistry, University of Malta, Malta.
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Department of Physiology and Biochemistry, University of Malta, Malta.
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43
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Casas-Torremocha D, Clascá F, Núñez Á. Posterior Thalamic Nucleus Modulation of Tactile Stimuli Processing in Rat Motor and Primary Somatosensory Cortices. Front Neural Circuits 2017; 11:69. [PMID: 29021744 PMCID: PMC5623691 DOI: 10.3389/fncir.2017.00069] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/12/2017] [Indexed: 12/18/2022] Open
Abstract
Rodents move rhythmically their facial whiskers and compute differences between signals predicted and those resulting from the movement to infer information about objects near their head. These computations are carried out by a large network of forebrain structures that includes the thalamus and the primary somatosensory (S1BF) and motor (M1wk) cortices. Spatially and temporally precise mechanorreceptive whisker information reaches the S1BF cortex via the ventroposterior medial thalamic nucleus (VPM). Other whisker-related information may reach both M1wk and S1BF via the axons from the posterior thalamic nucleus (Po). However, Po axons may convey, in addition to direct sensory signals, the dynamic output of computations between whisker signals and descending motor commands. It has been proposed that this input may be relevant for adjusting cortical responses to predicted vs. unpredicted whisker signals, but the effects of Po input on M1wk and S1BF function have not been directly tested or compared in vivo. Here, using electrophysiology, optogenetics and pharmacological tools, we compared in adult rats M1wk and S1BF in vivo responses in the whisker areas of the motor and primary somatosensory cortices to passive multi-whisker deflection, their dependence on Po activity, and their changes after a brief intense activation of Po axons. We report that the latencies of the first component of tactile-evoked local field potentials in M1wk and S1BF are similar. The evoked potentials decrease markedly in M1wk, but not in S1BF, by injection in Po of the GABAA agonist muscimol. A brief high-frequency electrical stimulation of Po decreases the responsivity of M1wk and S1BF cells to subsequent whisker stimulation. This effect is prevented by the local application of omega-agatoxin, suggesting that it may in part depend on GABA release by fast-spiking parvalbumin (PV)-expressing cortical interneurons. Local optogenetic activation of Po synapses in different cortical layers also diminishes M1wk and S1BF responses. This effect is most pronounced in the superficial layers of both areas, known to be the main source and target of their reciprocal cortico-cortical connections.
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Affiliation(s)
- Diana Casas-Torremocha
- Department of Anatomy, Histology and Neuroscience, Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain
| | - Francisco Clascá
- Department of Anatomy, Histology and Neuroscience, Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain
| | - Ángel Núñez
- Department of Anatomy, Histology and Neuroscience, Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain
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Maheshwari A, Akbar A, Wang M, Marks RL, Yu K, Park S, Foster BL, Noebels JL. Persistent aberrant cortical phase-amplitude coupling following seizure treatment in absence epilepsy models. J Physiol 2017; 595:7249-7260. [PMID: 28901011 DOI: 10.1113/jp274696] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/16/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS In two monogenic models of absence epilepsy, interictal beta/gamma power is augmented in homozygous stargazer (stg/stg) but not homozygous tottering (tg/tg) mice. There are distinct gene-linked patterns of aberrant phase-amplitude coupling in the interictal EEG of both stg/stg and tg/tg mice, compared to +/+ and stg/+ mice. Treatment with ethosuximide significantly blocks seizures in both genotypes, but the abnormal phase-amplitude coupling remains. Seizure-free stg/+ mice have normal power and phase-amplitude coupling, but beta/gamma power is significantly reduced with NMDA receptor blockade, revealing a latent cortical network phenotype that is separable from, and therefore not a result of, seizures. Altogether, these findings reveal gene-linked quantitative electrographic biomarkers free from epileptiform activity, and provide a potential network correlate for persistent cognitive deficits in absence epilepsy despite effective treatment. ABSTRACT In childhood absence epilepsy, cortical seizures are brief and intermittent; however there are extended periods without behavioural or electrographic ictal events. This genetic disorder is associated with variable degrees of cognitive dysfunction, but no consistent functional biomarkers that might provide insight into interictal cortical function have been described. Previous work in monogenic mouse models of absence epilepsy have shown that the interictal EEG displays augmented beta/gamma power in homozygous stargazer (stg/stg) mice bearing a presynaptic AMPA receptor defect, but not homozygous tottering (tg/tg) mice with a P/Q type calcium channel mutation. To further evaluate the interictal EEG, we quantified phase-amplitude coupling (PAC) in stg/stg, stg/+, tg/tg and wild-type (+/+) mice. We found distinct gene-linked patterns of aberrant PAC in stg/stg and tg/tg mice compared to +/+ and stg/+ mice. Treatment with ethosuximide significantly blocks seizures in both stg/stg and tg/tg, but the abnormal PAC remains. Stg/+ mice are seizure free with normal baseline beta/gamma power and normal theta-gamma PAC, but like stg/stg mice, beta/gamma power is significantly reduced by NMDA receptor blockade, a treatment that paradoxically enhances seizures in stg/stg mice. Stg/+ mice, therefore, have a latent cortical network phenotype that is veiled by NMDA-mediated neurotransmission. Altogether, these findings reveal gene-linked quantitative electrographic biomarkers in the absence of epileptiform activity and provide a potential network correlate for persistent cognitive deficits in absence epilepsy despite effective treatment.
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Affiliation(s)
- Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Abraham Akbar
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Mai Wang
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA.,Rice University, Houston, TX, USA
| | - Rachel L Marks
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Katherine Yu
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA.,Rice University, Houston, TX, USA
| | - Suhyeorn Park
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Brett L Foster
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Jeffrey L Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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45
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Functions and dysfunctions of neocortical inhibitory neuron subtypes. Nat Neurosci 2017; 20:1199-1208. [PMID: 28849791 DOI: 10.1038/nn.4619] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/30/2017] [Indexed: 02/08/2023]
Abstract
Neocortical inhibitory neurons exhibit remarkably diverse morphology, physiological properties and connectivity. Genetic access to molecularly defined subtypes of inhibitory neurons has aided their functional characterization in recent years. These studies have established that, instead of simply balancing excitatory neuron activity, inhibitory neurons actively shape excitatory circuits in a subtype-specific manner. We review the emerging view that inhibitory neuron subtypes perform context-dependent modulation of excitatory activity, as well as regulate experience-dependent plasticity of excitatory circuits. We then review the roles of neuromodulators in regulating the subtype-specific functions of inhibitory neurons. Finally, we discuss the idea that dysfunctions of inhibitory neuron subtypes may be responsible for various aspects of neurological disorders.
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Abstract
Cortical networks are composed of glutamatergic excitatory projection neurons and local GABAergic inhibitory interneurons that gate signal flow and sculpt network dynamics. Although they represent a minority of the total neocortical neuronal population, GABAergic interneurons are highly heterogeneous, forming functional classes based on their morphological, electrophysiological, and molecular features, as well as connectivity and in vivo patterns of activity. Here we review our current understanding of neocortical interneuron diversity and the properties that distinguish cell types. We then discuss how the involvement of multiple cell types, each with a specific set of cellular properties, plays a crucial role in diversifying and increasing the computational power of a relatively small number of simple circuit motifs forming cortical networks. We illustrate how recent advances in the field have shed light onto the mechanisms by which GABAergic inhibition contributes to network operations.
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47
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Chen M, Guo D, Xia Y, Yao D. Control of Absence Seizures by the Thalamic Feed-Forward Inhibition. Front Comput Neurosci 2017; 11:31. [PMID: 28491031 PMCID: PMC5405150 DOI: 10.3389/fncom.2017.00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/10/2017] [Indexed: 11/17/2022] Open
Abstract
As a subtype of idiopathic generalized epilepsies, absence epilepsy is believed to be caused by pathological interactions within the corticothalamic (CT) system. Using a biophysical mean-field model of the CT system, we demonstrate here that the feed-forward inhibition (FFI) in thalamus, i.e., the pathway from the cerebral cortex (Ctx) to the thalamic reticular nucleus (TRN) and then to the specific relay nuclei (SRN) of thalamus that are also directly driven by the Ctx, may participate in controlling absence seizures. In particular, we show that increasing the excitatory Ctx-TRN coupling strength can significantly suppress typical electrical activities during absence seizures. Further, investigation demonstrates that the GABAA- and GABAB-mediated inhibitions in the TRN-SRN pathway perform combination roles in the regulation of absence seizures. Overall, these results may provide an insightful mechanistic understanding of how the thalamic FFI serves as an intrinsic regulator contributing to the control of absence seizures.
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Affiliation(s)
- Mingming Chen
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of ChinaChengdu, China
| | - Daqing Guo
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of ChinaChengdu, China.,Center for Information in BioMedicine, University of Electronic Science and Technology of ChinaChengdu, China
| | - Yang Xia
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of ChinaChengdu, China.,Center for Information in BioMedicine, University of Electronic Science and Technology of ChinaChengdu, China
| | - Dezhong Yao
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of ChinaChengdu, China.,Center for Information in BioMedicine, University of Electronic Science and Technology of ChinaChengdu, China
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48
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Makinson CD, Tanaka BS, Sorokin JM, Wong JC, Christian CA, Goldin AL, Escayg A, Huguenard JR. Regulation of Thalamic and Cortical Network Synchrony by Scn8a. Neuron 2017; 93:1165-1179.e6. [PMID: 28238546 DOI: 10.1016/j.neuron.2017.01.031] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/30/2016] [Accepted: 01/30/2017] [Indexed: 12/22/2022]
Abstract
Voltage-gated sodium channel (VGSC) mutations cause severe epilepsies marked by intermittent, pathological hypersynchronous brain states. Here we present two mechanisms that help to explain how mutations in one VGSC gene, Scn8a, contribute to two distinct seizure phenotypes: (1) hypoexcitation of cortical circuits leading to convulsive seizure resistance, and (2) hyperexcitation of thalamocortical circuits leading to non-convulsive absence epilepsy. We found that loss of Scn8a leads to altered RT cell intrinsic excitability and a failure in recurrent RT synaptic inhibition. We propose that these deficits cooperate to enhance thalamocortical network synchrony and generate pathological oscillations. To our knowledge, this finding is the first clear demonstration of a pathological state tied to disruption of the RT-RT synapse. Our observation that loss of a single gene in the thalamus of an adult wild-type animal is sufficient to cause spike-wave discharges is striking and represents an example of absence epilepsy of thalamic origin.
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Affiliation(s)
- Christopher D Makinson
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA
| | - Brian S Tanaka
- Departments of Microbiology and Molecular Genetics and Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Jordan M Sorokin
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA
| | - Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Catherine A Christian
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA
| | - Alan L Goldin
- Departments of Microbiology and Molecular Genetics and Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA.
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304, USA.
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49
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Huang Y, Xiao H, Qin X, Nong Y, Zou D, Wu Y. The genetic relationship between epilepsy and hemiplegic migraine. Neuropsychiatr Dis Treat 2017; 13:1175-1179. [PMID: 28479855 PMCID: PMC5411172 DOI: 10.2147/ndt.s132451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Epilepsy and migraine are common diseases of the nervous system and share genetic and pathophysiological mechanisms. Familial hemiplegic migraine is an autosomal dominant disease. It is often used as a model of migraine. Four genes often contain one or more mutations in both epilepsy and hemiplegic migraine patients (ie, CACNA1A, ATP1A2, SCN1A, and PRRT2). A better understanding of the shared genetics of epilepsy and hemiplegic migraine may reveal new strategic directions for research and treatment of both the disorders.
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Affiliation(s)
- Yiqing Huang
- Department of Neurology, Guigang City People's Hospital and the Eighth Affiliated Hospital of Guangxi Medical University, Guigang, People's Republic of China
| | - Hai Xiao
- Department of Neurology, Guigang City People's Hospital and the Eighth Affiliated Hospital of Guangxi Medical University, Guigang, People's Republic of China
| | - Xingyue Qin
- Department of Neurology, Guigang City People's Hospital and the Eighth Affiliated Hospital of Guangxi Medical University, Guigang, People's Republic of China
| | - Yuan Nong
- Department of Neurology, Guigang City People's Hospital and the Eighth Affiliated Hospital of Guangxi Medical University, Guigang, People's Republic of China
| | - Donghua Zou
- Department of Neurology, The Fifth Affiliated Hospital of Guangxi Medical University and the First People's Hospital of Nanning, Nanning, People's Republic of China
| | - Yuan Wu
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People's Republic of China
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50
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Su J, Chen J, Lippold K, Monavarfeshani A, Carrillo GL, Jenkins R, Fox MA. Collagen-derived matricryptins promote inhibitory nerve terminal formation in the developing neocortex. J Cell Biol 2016; 212:721-36. [PMID: 26975851 PMCID: PMC4792079 DOI: 10.1083/jcb.201509085] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inhibitory synapses comprise only ∼20% of the total synapses in the mammalian brain but play essential roles in controlling neuronal activity. In fact, perturbing inhibitory synapses is associated with complex brain disorders, such as schizophrenia and epilepsy. Although many types of inhibitory synapses exist, these disorders have been strongly linked to defects in inhibitory synapses formed by Parvalbumin-expressing interneurons. Here, we discovered a novel role for an unconventional collagen-collagen XIX-in the formation of Parvalbumin(+) inhibitory synapses. Loss of this collagen results not only in decreased inhibitory synapse number, but also in the acquisition of schizophrenia-related behaviors. Mechanistically, these studies reveal that a proteolytically released fragment of this collagen, termed a matricryptin, promotes the assembly of inhibitory nerve terminals through integrin receptors. Collectively, these studies not only identify roles for collagen-derived matricryptins in cortical circuit formation, but they also reveal a novel paracrine mechanism that regulates the assembly of these synapses.
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Affiliation(s)
- Jianmin Su
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016
| | - Jiang Chen
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016
| | - Kumiko Lippold
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016
| | - Aboozar Monavarfeshani
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016 Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | | | - Rachel Jenkins
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Michael A Fox
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016 Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
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