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Kida H, Toyoshima S, Kawakami R, Sakimoto Y, Mitsushima D. Properties of layer V pyramidal neurons in the primary motor cortex that represent acquired motor skills. Neuroscience 2024; 559:54-63. [PMID: 39209105 DOI: 10.1016/j.neuroscience.2024.08.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 08/19/2024] [Accepted: 08/22/2024] [Indexed: 09/04/2024]
Abstract
Layer V neurons in primary motor cortex (M1) are required for motor skill learning. We analyzed training-induced plasticity using a whole-cell slice patch-clamp technique with a rotor rod task, and found that training induces diverse changes in intrinsic properties and synaptic plasticity in M1 layer V neurons. Although the causal relationship between specific cellular changes and motor performance is unclear, by linking individual motor performance to cellular/synaptic functions, we identified several cellular and synaptic parameters that represent acquired motor skills. With respect to cellular properties, motor performance was positively correlated with resting membrane potential and fast afterhyperpolarization, but not with the membrane resistance, capacitance, or threshold. With respect to synaptic function, the performance was positively correlated with AMPA receptor-mediated postsynaptic currents, but not with GABAA receptor-mediated postsynaptic currents. With respect to live imaging analysis in Thy1-YFP mice, we further demonstrated a cross-correlation between motor performance, spine head volume, and self-entropy per spine. In the present study, we identified several changes in M1 layer V pyramidal neurons after motor training that represent acquired motor skills. Furthermore, training increased extracellular acetylcholine levels known to promote synaptic plasticity, which is correlated with individual motor performance. These results suggest that systematic control of specific intracellular parameters and enhancement of synaptic plasticity in M1 layer V neurons may be useful for improving motor skills.
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Affiliation(s)
- H Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan.
| | - S Toyoshima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - R Kawakami
- Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine, Ehime University, Ehime 791-0295, Japan
| | - Y Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - D Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan.
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2
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Hansel C, Yuste R. Neural ensembles: role of intrinsic excitability and its plasticity. Front Cell Neurosci 2024; 18:1440588. [PMID: 39144154 PMCID: PMC11322048 DOI: 10.3389/fncel.2024.1440588] [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: 05/29/2024] [Accepted: 07/18/2024] [Indexed: 08/16/2024] Open
Abstract
Synaptic connectivity defines groups of neurons that engage in correlated activity during specific functional tasks. These co-active groups of neurons form ensembles, the operational units involved in, for example, sensory perception, motor coordination and memory (then called an engram). Traditionally, ensemble formation has been thought to occur via strengthening of synaptic connections via long-term potentiation (LTP) as a plasticity mechanism. This synaptic theory of memory arises from the learning rules formulated by Hebb and is consistent with many experimental observations. Here, we propose, as an alternative, that the intrinsic excitability of neurons and its plasticity constitute a second, non-synaptic mechanism that could be important for the initial formation of ensembles. Indeed, enhanced neural excitability is widely observed in multiple brain areas subsequent to behavioral learning. In cortical structures and the amygdala, excitability changes are often reported as transient, even though they can last tens of minutes to a few days. Perhaps it is for this reason that they have been traditionally considered as modulatory, merely supporting ensemble formation by facilitating LTP induction, without further involvement in memory function (memory allocation hypothesis). We here suggest-based on two lines of evidence-that beyond modulating LTP allocation, enhanced excitability plays a more fundamental role in learning. First, enhanced excitability constitutes a signature of active ensembles and, due to it, subthreshold synaptic connections become suprathreshold in the absence of synaptic plasticity (iceberg model). Second, enhanced excitability promotes the propagation of dendritic potentials toward the soma and allows for enhanced coupling of EPSP amplitude (LTP) to the spike output (and thus ensemble participation). This permissive gate model describes a need for permanently increased excitability, which seems at odds with its traditional consideration as a short-lived mechanism. We propose that longer modifications in excitability are made possible by a low threshold for intrinsic plasticity induction, suggesting that excitability might be on/off-modulated at short intervals. Consistent with this, in cerebellar Purkinje cells, excitability lasts days to weeks, which shows that in some circuits the duration of the phenomenon is not a limiting factor in the first place. In our model, synaptic plasticity defines the information content received by neurons through the connectivity network that they are embedded in. However, the plasticity of cell-autonomous excitability could dynamically regulate the ensemble participation of individual neurons as well as the overall activity state of an ensemble.
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Affiliation(s)
- Christian Hansel
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, IL, United States
| | - Rafael Yuste
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY, United States
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3
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Lin TF, Busch SE, Hansel C. Intrinsic and synaptic determinants of receptive field plasticity in Purkinje cells of the mouse cerebellum. Nat Commun 2024; 15:4645. [PMID: 38821918 PMCID: PMC11143328 DOI: 10.1038/s41467-024-48373-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 04/28/2024] [Indexed: 06/02/2024] Open
Abstract
Non-synaptic (intrinsic) plasticity of membrane excitability contributes to aspects of memory formation, but it remains unclear whether it merely facilitates synaptic long-term potentiation or plays a permissive role in determining the impact of synaptic weight increase. We use tactile stimulation and electrical activation of parallel fibers to probe intrinsic and synaptic contributions to receptive field plasticity in awake mice during two-photon calcium imaging of cerebellar Purkinje cells. Repetitive activation of both stimuli induced response potentiation that is impaired in mice with selective deficits in either synaptic or intrinsic plasticity. Spatial analysis of calcium signals demonstrated that intrinsic, but not synaptic plasticity, enhances the spread of dendritic parallel fiber response potentiation. Simultaneous dendrite and axon initial segment recordings confirm these dendritic events affect axonal output. Our findings support the hypothesis that intrinsic plasticity provides an amplification mechanism that exerts a permissive control over the impact of long-term potentiation on neuronal responsiveness.
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Affiliation(s)
- Ting-Feng Lin
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Silas E Busch
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Christian Hansel
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, IL, USA.
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Neyhart E, Zhou N, Munn BR, Law RG, Smith C, Mridha ZH, Blanco FA, Li G, Li Y, McGinley MJ, Shine JM, Reimer J. Cortical acetylcholine dynamics are predicted by cholinergic axon activity and behavior state. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.14.567116. [PMID: 38352527 PMCID: PMC10862699 DOI: 10.1101/2023.11.14.567116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Even under spontaneous conditions and in the absence of changing environmental demands, awake animals alternate between increased or decreased periods of alertness. These changes in brain state can occur rapidly, on a timescale of seconds, and neuromodulators such as acetylcholine (ACh) are thought to play an important role in driving these spontaneous state transitions. Here, we perform the first simultaneous imaging of ACh sensors and GCaMP-expressing axons in vivo, to examine the spatiotemporal properties of cortical ACh activity and release during spontaneous changes in behavioral state. We observed a high correlation between simultaneously recorded basal forebrain axon activity and neuromodulator sensor fluorescence around periods of locomotion and pupil dilation. Consistent with volume transmission of ACh, increases in axon activity were accompanied by increases in local ACh levels that fell off with the distance from the nearest axon. GRAB-ACh fluorescence could be accurately predicted from axonal activity alone, providing the first validation that neuromodulator axon activity is a reliable proxy for nearby neuromodulator levels. Deconvolution of fluorescence traces allowed us to account for the kinetics of the GRAB-ACh sensor and emphasized the rapid clearance of ACh for smaller transients outside of running periods. Finally, we trained a predictive model of ACh fluctuations from the combination of pupil size and running speed; this model performed better than using either variable alone, and generalized well to unseen data. Overall, these results contribute to a growing understanding of the precise timing and spatial characteristics of cortical ACh during fast brain state transitions.
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Affiliation(s)
- Erin Neyhart
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - Na Zhou
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - Brandon R Munn
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Australia
- Complex Systems Group, School of Physics, Faculty of Science, The University of Sydney, Australia
| | - Robert G Law
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - Cameron Smith
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - Zakir H Mridha
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - Francisco A Blanco
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - Guochuan Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Matthew J McGinley
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
| | - James M Shine
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Australia
- Complex Systems Group, School of Physics, Faculty of Science, The University of Sydney, Australia
| | - Jacob Reimer
- Neuroscience Department, Baylor College of Medicine, Houston, Texas, USA
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Blankenship HE, Carter KA, Cassidy NT, Markiewicz AN, Thellmann MI, Sharpe AL, Freeman WM, Beckstead MJ. VTA dopamine neurons are hyperexcitable in 3xTg-AD mice due to casein kinase 2-dependent SK channel dysfunction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567486. [PMID: 38014232 PMCID: PMC10680865 DOI: 10.1101/2023.11.16.567486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Alzheimer's disease (AD) patients exhibit neuropsychiatric symptoms that extend beyond classical cognitive deficits, suggesting involvement of subcortical areas. Here, we investigated the role of midbrain dopamine (DA) neurons in AD using the amyloid + tau-driven 3xTg-AD mouse model. We found deficits in reward-based operant learning in AD mice, suggesting possible VTA DA neuron dysregulation. Physiological assessment revealed hyperexcitability and disrupted firing in DA neurons caused by reduced activity of small-conductance calcium-activated potassium (SK) channels. RNA sequencing from contents of single patch-clamped DA neurons (Patch-seq) identified up-regulation of the SK channel modulator casein kinase 2 (CK2). Pharmacological inhibition of CK2 restored SK channel activity and normal firing patterns in 3xTg-AD mice. These findings shed light on a complex interplay between neuropsychiatric symptoms and subcortical circuits in AD, paving the way for novel treatment strategies.
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Lin TF, Busch SE, Hansel C. Intrinsic and synaptic determinants of receptive field plasticity in Purkinje cells of the mouse cerebellum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.19.549760. [PMID: 37502848 PMCID: PMC10370111 DOI: 10.1101/2023.07.19.549760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Non-synaptic ('intrinsic') plasticity of membrane excitability contributes to aspects of memory formation, but it remains unclear whether it merely facilitates synaptic long-term potentiation (LTP), or whether it plays a permissive role in determining the impact of synaptic weight increase. We use tactile stimulation and electrical activation of parallel fibers to probe intrinsic and synaptic contributions to receptive field (RF) plasticity in awake mice during two-photon calcium imaging of cerebellar Purkinje cells. Repetitive activation of both stimuli induced response potentiation that is impaired in mice with selective deficits in either intrinsic plasticity (SK2 KO) or LTP (CaMKII TT305/6VA). Intrinsic, but not synaptic, plasticity expands the local, dendritic RF representation. Simultaneous dendrite and axon initial segment recordings confirm that these dendritic events affect axonal output. Our findings support the hypothesis that intrinsic plasticity provides an amplification mechanism that exerts a permissive control over the impact of LTP on neuronal responsiveness.
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Affiliation(s)
- Ting-Feng Lin
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| | - Silas E Busch
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| | - Christian Hansel
- Department of Neurobiology and Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
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7
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Zhang M, Luo Y, Wang J, Sun Y, Xie B, Zhang L, Cong B, Ma C, Wen D. Roles of nucleus accumbens shell small-conductance calcium-activated potassium channels in the conditioned fear freezing. J Psychiatr Res 2023; 163:180-194. [PMID: 37216772 DOI: 10.1016/j.jpsychires.2023.05.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/27/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
BACKGROUND Posttraumatic stress disorder (PTSD), a psychiatric disorder caused by stressful events, is characterized by long-lasting fear memory. The nucleus accumbens shell (NAcS) is a key brain region that regulates fear-associated behavior. Small-conductance calcium-activated potassium channels (SK channels) play a key role in regulating the excitability of NAcS medium spiny neurons (MSNs) but their mechanisms of action in fear freezing are unclear. METHOD We established an animal model of traumatic memory using conditioned fear freezing paradigm, and investigated the alterations in SK channels of NAc MSNs subsequent to fear conditioning in mice. We then utilized an adeno-associated virus (AAV) transfection system to overexpress the SK3 subunit and explore the function of the NAcS MSNs SK3 channel in conditioned fear freezing. RESULTS Fear conditioning activated NAcS MSNs with enhanced excitability and reduced the SK channel-mediated medium after-hyperpolarization (mAHP) amplitude. The expression of NAcS SK3 were also reduced time-dependently. The overexpression of NAcS SK3 impaired conditioned fear consolidation without affecting conditioned fear expression, and blocked fear conditioning-induced alterations in NAcS MSNs excitability and mAHP amplitude. Additionally, the amplitudes of mEPSC, AMPAR/NMDAR ratio, and membrane surface GluA1/A2 expression in NAcS MSNs was increased by fear conditioning and returned to normal levels upon SK3 overexpression, indicating that fear conditioning-induced decrease of SK3 expression caused postsynaptic excitation by facilitating AMPAR transmission to the membrane. CONCLUSION These findings show that the NAcS MSNs SK3 channel plays a critical role in conditioned fear consolidation and that it may influence PTSD pathogenesis, making it a potential therapeutic target against PTSD.
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Affiliation(s)
- Minglong Zhang
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Yixiao Luo
- Hunan Province People's Hospital, The First-Affiliated Hospital of Hunan Normal University, Changsha, 410081, PR China
| | - Jian Wang
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Yufei Sun
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Bing Xie
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Ludi Zhang
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Bin Cong
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Chunling Ma
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China.
| | - Di Wen
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China.
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Yang R, Feng X, Arias-Cavieres A, Mitchell RM, Polo A, Hu K, Zhong R, Qi C, Zhang RS, Westneat N, Portillo CA, Nobrega MA, Hansel C, Garcia Iii AJ, Zhang X. Upregulation of SYNGAP1 expression in mice and human neurons by redirecting alternative splicing. Neuron 2023; 111:1637-1650.e5. [PMID: 36917980 PMCID: PMC10198817 DOI: 10.1016/j.neuron.2023.02.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/20/2022] [Accepted: 02/13/2023] [Indexed: 03/14/2023]
Abstract
The Ras GTPase-activating protein SYNGAP1 plays a central role in synaptic plasticity, and de novo SYNGAP1 mutations are among the most frequent causes of autism and intellectual disability. How SYNGAP1 is regulated during development and how to treat SYNGAP1-associated haploinsufficiency remain challenging questions. Here, we characterize an alternative 3' splice site (A3SS) of SYNGAP1 that induces nonsense-mediated mRNA decay (A3SS-NMD) in mouse and human neural development. We demonstrate that PTBP1/2 directly bind to and promote SYNGAP1 A3SS inclusion. Genetic deletion of the Syngap1 A3SS in mice upregulates Syngap1 protein and alleviates the long-term potentiation and membrane excitability deficits caused by a Syngap1 knockout allele. We further report a splice-switching oligonucleotide (SSO) that converts SYNGAP1 unproductive isoform to the functional form in human iPSC-derived neurons. This study describes the regulation and function of SYNGAP1 A3SS-NMD, the genetic rescue of heterozygous Syngap1 knockout mice, and the development of an SSO to potentially alleviate SYNGAP1-associated haploinsufficiency.
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Affiliation(s)
- Runwei Yang
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xinran Feng
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Alejandra Arias-Cavieres
- Section of Emergency Medicine, Department of Medicine, Institute for Integrative Physiology, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Robin M Mitchell
- Department of Neurobiology, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Ashleigh Polo
- Section of Emergency Medicine, Department of Medicine, Institute for Integrative Physiology, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Kaining Hu
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Rong Zhong
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Cai Qi
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Rachel S Zhang
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Nathaniel Westneat
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Cristabel A Portillo
- Department of Neurobiology, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA; Department of Anatomy and Neurobiology, University of California Irvine, Irvine, CA 92697, USA
| | - Marcelo A Nobrega
- Department of Human Genetics, the University of Chicago, Chicago, IL 60637, USA
| | - Christian Hansel
- Department of Neurobiology, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Alfredo J Garcia Iii
- Section of Emergency Medicine, Department of Medicine, Institute for Integrative Physiology, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaochang Zhang
- Department of Human Genetics, Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA.
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Hosoi Y, Akita T, Watanabe M, Ito T, Miyajima H, Fukuda A. Taurine depletion during fetal and postnatal development blunts firing responses of neocortical layer II/III pyramidal neurons. Front Mol Neurosci 2022; 15:806798. [PMID: 36466806 PMCID: PMC9712787 DOI: 10.3389/fnmol.2022.806798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 10/27/2022] [Indexed: 08/22/2023] Open
Abstract
Fetal and infant brains are rich in maternally derived taurine. We previously demonstrated that taurine action regulates the cation-chloride cotransporter activity and the differentiation and radial migration of pyramidal neuron progenitors in the developing neocortex of rodent fetuses. Here we examined the effects of fetal and infantile taurine depletion caused by knockout of the taurine transporter Slc6a6 on firing properties of layer II/III pyramidal neurons in the mouse somatosensory cortex at 3 weeks of postnatal age, using the whole-cell patch-clamp technique. The membrane excitability under resting conditions was similar between the neurons in knockout mice and those in wildtype littermates. However, the frequency of repetitive spike firing during moderate current injection was significantly lower, along with lower membrane voltage levels during interspike intervals in knockout neurons. When strong currents were injected, by which repetitive firing was rapidly abolished due to inactivation of voltage-gated Na+ channels in wildtype neurons, the firing in knockout neurons lasted for a much longer period than in wildtype neurons. This was due to much lower membrane voltage levels during interspike intervals in knockout neurons, promoting greater recovery of voltage-gated Na+ channels from inactivation. Thus, taurine depletion in pyramidal neurons blunted neuronal responses to external stimuli through increasing the stability of repetitive firing, presumably mediated by larger increases in membrane K+ conductance during interspike intervals.
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Affiliation(s)
- Yasushi Hosoi
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
- Division of Health Science, Department of Basic Nursing, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Takashi Ito
- Department of Biosciences and Biotechnology, Fukui Prefectural University, Fukui, Japan
| | - Hiroaki Miyajima
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Sun J, Liu Y, Hao X, Baudry M, Bi X. Lack of UBE3A-Mediated Regulation of Synaptic SK2 Channels Contributes to Learning and Memory Impairment in the Female Mouse Model of Angelman Syndrome. Neural Plast 2022; 2022:3923384. [PMID: 36237484 PMCID: PMC9553421 DOI: 10.1155/2022/3923384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/16/2022] [Indexed: 11/29/2022] Open
Abstract
Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe developmental delay, motor impairment, language and cognition deficits, and often with increased seizure activity. AS is caused by deficiency of UBE3A, which is both an E3 ligase and a cofactor for transcriptional regulation. We previously showed that the small conductance potassium channel protein SK2 is a UBE3A substrate, and that increased synaptic SK2 levels contribute to impairments in synaptic plasticity and fear-conditioning memory, as inhibition of SK2 channels significantly improved both synaptic plasticity and fear memory in male AS mice. In the present study, we investigated UBE3a-mediated regulation of synaptic plasticity and fear-conditioning in female AS mice. Results from both western blot and immunofluorescence analyses showed that synaptic SK2 levels were significantly increased in hippocampus of female AS mice, as compared to wild-type (WT) littermates. Like in male AS mice, long-term potentiation (LTP) was significantly reduced while long-term depression (LTD) was enhanced at hippocampal CA3-CA1 synapses of female AS mice, as compared to female WT mice. Both alterations were significantly reduced by treatment with the SK2 inhibitor, apamin. The shunting effect of SK2 channels on NMDA receptor was significantly larger in female AS mice as compared to female WT mice. Female AS mice also showed impairment in both contextual and tone memory recall, and this impairment was significantly reduced by apamin treatment. Our results indicate that like male AS mice, female AS mice showed significant impairment in both synaptic plasticity and fear-conditioning memory due to increased levels of synaptic SK2 channels. Any therapeutic strategy to reduce SK2-mediated inhibition of NMDAR should be beneficial to both male and female patients.
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Affiliation(s)
- Jiandong Sun
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California 91766, USA
| | - Yan Liu
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California 91766, USA
| | - Xiaoning Hao
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California 91766, USA
| | - Michel Baudry
- College of Dental Medicine, Western University of Health Sciences, Pomona, California 91766, USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California 91766, USA
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Yamawaki Y, Wada Y, Matsui S, Ohtsuki G. Microglia-triggered hypoexcitability plasticity of pyramidal neurons in the rat medial prefrontal cortex. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100028. [DOI: 10.1016/j.crneur.2022.100028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 01/14/2022] [Accepted: 01/30/2022] [Indexed: 12/16/2022] Open
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12
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Daou A, Margoliash D. Intrinsic plasticity and birdsong learning. Neurobiol Learn Mem 2021; 180:107407. [PMID: 33631346 DOI: 10.1016/j.nlm.2021.107407] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 10/28/2020] [Accepted: 02/11/2021] [Indexed: 10/22/2022]
Abstract
Although information processing and storage in the brain is thought to be primarily orchestrated by synaptic plasticity, other neural mechanisms such as intrinsic plasticity are available. While a number of recent studies have described the plasticity of intrinsic excitability in several types of neurons, the significance of non-synaptic mechanisms in memory and learning remains elusive. After reviewing plasticity of intrinsic excitation in relation to learning and homeostatic mechanisms, we focus on the intrinsic properties of a class of basal-ganglia projecting song system neurons in zebra finch, how these related to each bird's unique learned song, how these properties change over development, and how they are maintained dynamically to rapidly change in response to auditory feedback perturbations. We place these results in the broader theme of learning and changes in intrinsic properties, emphasizing the computational implications of this form of plasticity, which are distinct from synaptic plasticity. The results suggest that exploring reciprocal interactions between intrinsic and network properties will be a fruitful avenue for understanding mechanisms of birdsong learning.
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Affiliation(s)
- Arij Daou
- University of Chicago, United States
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Blockade of the M1 muscarinic acetylcholine receptors impairs eyeblink serial feature-positive discrimination learning in mice. PLoS One 2020; 15:e0237451. [PMID: 32790748 PMCID: PMC7425847 DOI: 10.1371/journal.pone.0237451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/27/2020] [Indexed: 11/19/2022] Open
Abstract
The serial feature-positive discrimination task requires the subjects to respond differentially to the identical stimulus depending on the temporal context given by a preceding cue stimulus. In the present study, we examined the involvement of the M1 muscarinic acetylcholine receptors using a selective M1 antagonist VU0255035 in the serial feature-positive discrimination task of eyeblink conditioning in mice. In this task, mice received a 2-s light stimulus as the conditional cue 5 or 6 s before the presentation of a 350-ms tone conditioned stimulus (CS) paired with a 100-ms peri-orbital electrical shock (cued trials), while they did not receive the cue before the presentation of the CS alone (non-cued trials). Each day mice randomly received 30 cued and 30 non-cued trials. We found that VU0255035 impaired acquisition of the conditional discrimination as well as the overall acquisition of the conditioned response (CR) and diminished the difference in onset latency of the CR between the cued and non-cued trials. VU0255035 administration to the control mice after sufficient learning did not impair the pre-acquired conditional discrimination or the CR expression itself. These effects of VU0255035 were almost similar to those with the scopolamine in our previous study, suggesting that among the several types of muscarinic acetylcholine receptors, the M1 receptors may play an important role in the acquisition of the conditional discrimination memory but not in mediating the discrimination itself after the memory had formed in the eyeblink serial feature-positive discrimination learning.
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