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Garcia-Garcia MG, Kapoor A, Akinwale O, Takemaru L, Kim TH, Paton C, Litwin-Kumar A, Schnitzer MJ, Luo L, Wagner MJ. A cerebellar granule cell-climbing fiber computation to learn to track long time intervals. Neuron 2024:S0896-6273(24)00366-0. [PMID: 38870929 DOI: 10.1016/j.neuron.2024.05.019] [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: 01/01/2024] [Revised: 03/31/2024] [Accepted: 05/16/2024] [Indexed: 06/15/2024]
Abstract
In classical cerebellar learning, Purkinje cells (PkCs) associate climbing fiber (CF) error signals with predictive granule cells (GrCs) that were active just prior (∼150 ms). The cerebellum also contributes to behaviors characterized by longer timescales. To investigate how GrC-CF-PkC circuits might learn seconds-long predictions, we imaged simultaneous GrC-CF activity over days of forelimb operant conditioning for delayed water reward. As mice learned reward timing, numerous GrCs developed anticipatory activity ramping at different rates until reward delivery, followed by widespread time-locked CF spiking. Relearning longer delays further lengthened GrC activations. We computed CF-dependent GrC→PkC plasticity rules, demonstrating that reward-evoked CF spikes sufficed to grade many GrC synapses by anticipatory timing. We predicted and confirmed that PkCs could thereby continuously ramp across seconds-long intervals from movement to reward. Learning thus leads to new GrC temporal bases linking predictors to remote CF reward signals-a strategy well suited for learning to track the long intervals common in cognitive domains.
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Affiliation(s)
- Martha G Garcia-Garcia
- National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD 20894, USA
| | - Akash Kapoor
- National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD 20894, USA
| | - Oluwatobi Akinwale
- National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD 20894, USA
| | - Lina Takemaru
- National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD 20894, USA
| | - Tony Hyun Kim
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Casey Paton
- National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD 20894, USA
| | - Ashok Litwin-Kumar
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Mark J Schnitzer
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Liqun Luo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Mark J Wagner
- National Institute of Neurological Disorders & Stroke, National Institutes of Health, Bethesda, MD 20894, USA.
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2
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Tian J, Bavencoffe AG, Zhu MX, Walters ET. Readiness of nociceptor cell bodies to generate spontaneous activity results from background activity of diverse ion channels and high input resistance. Pain 2024; 165:893-907. [PMID: 37862056 PMCID: PMC10950548 DOI: 10.1097/j.pain.0000000000003091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/09/2023] [Indexed: 10/21/2023]
Abstract
ABSTRACT Nociceptor cell bodies generate "spontaneous" discharge that can promote ongoing pain in persistent pain conditions. Little is known about the underlying mechanisms. Recordings from nociceptor cell bodies (somata) dissociated from rodent and human dorsal root ganglia have shown that previous pain in vivo is associated with low-frequency discharge controlled by irregular depolarizing spontaneous fluctuations of membrane potential (DSFs), likely produced by transient inward currents across the somal input resistance. Using mouse nociceptors, we show that DSFs are associated with high somal input resistance over a wide range of membrane potentials, including depolarized levels where DSFs approach action potential (AP) threshold. Input resistance and both the amplitude and frequency of DSFs were increased in neurons exhibiting spontaneous activity. Ion substitution experiments indicated that the depolarizing phase of DSFs is generated by spontaneous opening of channels permeable to Na + or Ca 2+ and that Ca 2+ -permeable channels are especially important for larger DSFs. Partial reduction of the amplitude or frequency of DSFs by perfusion of pharmacological inhibitors indicated small but significant contributions from Nav1.7, Nav1.8, TRPV1, TRPA1, TRPM4, and N-type Ca 2+ channels. Less specific blockers suggested a contribution from NALCN channels, and global knockout suggested a role for Nav1.9. The combination of high somal input resistance plus background activity of diverse ion channels permeable to Na + or Ca 2+ produces DSFs that are poised to reach AP threshold if resting membrane potential depolarizes, AP threshold decreases, or DSFs become enhanced-all of which can occur under painful neuropathic and inflammatory conditions.
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Affiliation(s)
- Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Alexis G. Bavencoffe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
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3
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Schreurs BG, O'Dell DE, Wang D. The Role of Cerebellar Intrinsic Neuronal Excitability, Synaptic Plasticity, and Perineuronal Nets in Eyeblink Conditioning. BIOLOGY 2024; 13:200. [PMID: 38534469 DOI: 10.3390/biology13030200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/29/2024] [Accepted: 03/19/2024] [Indexed: 03/28/2024]
Abstract
Evidence is strong that, in addition to fine motor control, there is an important role for the cerebellum in cognition and emotion. The deep nuclei of the mammalian cerebellum also contain the highest density of perineural nets-mesh-like structures that surround neurons-in the brain, and it appears there may be a connection between these nets and cognitive processes, particularly learning and memory. Here, we review how the cerebellum is involved in eyeblink conditioning-a particularly well-understood form of learning and memory-and focus on the role of perineuronal nets in intrinsic membrane excitability and synaptic plasticity that underlie eyeblink conditioning. We explore the development and role of perineuronal nets and the in vivo and in vitro evidence that manipulations of the perineuronal net in the deep cerebellar nuclei affect eyeblink conditioning. Together, these findings provide evidence of an important role for perineuronal net in learning and memory.
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Affiliation(s)
- Bernard G Schreurs
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
| | - Deidre E O'Dell
- Department of Biology, Earth and Environmental Sciences, Pennsylvania Western (PennWest) University, California, PA 15419, USA
| | - Desheng Wang
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
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4
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Lobule-Related Action Potential Shape- and History-Dependent Current Integration in Purkinje Cells of Adult and Developing Mice. Cells 2023; 12:cells12040623. [PMID: 36831290 PMCID: PMC9953991 DOI: 10.3390/cells12040623] [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: 01/06/2023] [Revised: 02/03/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Purkinje cells (PCs) are the principal cells of the cerebellar cortex and form a central element in the modular organization of the cerebellum. Differentiation of PCs based on gene expression profiles revealed two subpopulations with distinct connectivity, action potential firing and learning-induced activity changes. However, which basal cell physiological features underlie the differences between these subpopulations and to what extent they integrate input differentially remains largely unclear. Here, we investigate the cellular electrophysiological properties of PC subpopulation in adult and juvenile mice. We found that multiple fundamental cell physiological properties, including membrane resistance and various aspects of the action potential shape, differ between PCs from anterior and nodular lobules. Moreover, the two PC subpopulations also differed in the integration of negative and positive current steps as well as in size of the hyperpolarization-activated current. A comparative analysis in juvenile mice confirmed that most of these lobule-specific differences are already present at pre-weaning ages. Finally, we found that current integration in PCs is input history-dependent for both positive and negative currents, but this is not a distinctive feature between anterior and nodular PCs. Our results support the concept of a fundamental differentiation of PCs subpopulations in terms of cell physiological properties and current integration, yet reveals that history-dependent input processing is consistent across PC subtypes.
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5
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Alejandre-García T, Kim S, Pérez-Ortega J, Yuste R. Intrinsic excitability mechanisms of neuronal ensemble formation. eLife 2022; 11:77470. [PMID: 35506662 PMCID: PMC9197391 DOI: 10.7554/elife.77470] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
Neuronal ensembles are coactive groups of cortical neurons, found in spontaneous and evoked activity, that can mediate perception and behavior. To understand the mechanisms that lead to the formation of ensembles, we co-activated layer 2/3 pyramidal neurons in brain slices from mouse visual cortex, in animals of both sexes, replicating in vitro an optogenetic protocol to generate ensembles in vivo. Using whole-cell and perforated patch-clamp pair recordings we found that, after optogenetic or electrical stimulation, coactivated neurons increased their correlated activity, a hallmark of ensemble formation. Coactivated neurons showed small biphasic changes in presynaptic plasticity, with an initial depression followed by a potentiation after a recovery period. Optogenetic and electrical stimulation also induced significant increases in frequency and amplitude of spontaneous EPSPs, even after single-cell stimulation. In addition, we observed unexpected strong and persistent increases in neuronal excitability after stimulation, with increases in membrane resistance and reductions in spike threshold. A pharmacological agent that blocks changes in membrane resistance reverted this effect. These significant increases in excitability can explain the observed biphasic synaptic plasticity. We conclude that cell-intrinsic changes in excitability are involved in the formation of neuronal ensembles. We propose an ‘iceberg’ model, by which increased neuronal excitability makes subthreshold connections suprathreshold, enhancing the effect of already existing synapses, and generating a new neuronal ensemble. In the brain, groups of neurons that are activated together – also known as neuronal ensembles – are the basic units that underpin perception and behavior. Yet, exactly how these coactive circuits are established remains under investigation. In 1949, Canadian psychologist Donald Hebb proposed that, when brains learn something new, the neurons which are activated together connect to form ensembles, and their connections become stronger each time this specific piece of knowledge is recalled. This idea that ‘neurons that fire together, wire together’ can explain how memories are acquired and recalled, by strengthening their wiring. However, recent studies have questioned whether strengthening connections is the only mechanism by which neural ensembles can be created. Changes in the excitability of neurons (how easily they are to fire and become activated) may also play a role. In other words, ensembles could emerge because certain neurons become more excitable and fire more readily. To solve this conundrum, Alejandre-García et al. examined both hypotheses in the same system. Neurons in slices of the mouse visual cortex were stimulated electrically or optically, via a technique that controls neural activity with light. The activity of individual neurons and their connections was then measured with electrodes. Spontaneous activity among connected neurons increased after stimulation, indicative of the formation of neuronal ensembles. Connected neurons also showed small changes in the strength of their connections, which first decreased and then rebounded after an initial recovery period. Intriguingly, cells also showed unexpected strong and persistent increases in neuronal excitability after stimulation, such that neurons fired more readily to the same stimulus. In other words, neurons maintained a cellular memory of having been stimulated. The authors conclude that ensembles form because connected neurons become more excitable, which in turn, may strengthen connections of the circuit at a later stage. These results provide fresh insights about the neural circuits underpinning learning and memory. In time, the findings could also help to understand disorders such as Alzheimer’s disease and schizophrenia, which are characterised by memory impairments and disordered thinking.
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Affiliation(s)
| | - Samuel Kim
- Department of Biological Sciences, Columbia University, New York, United States
| | - Jesús Pérez-Ortega
- Department of Biological Sciences, Columbia University, New York, United States
| | - Rafael Yuste
- Department of Biological Sciences, Columbia University, New York, United States
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6
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Ohtsuki G, Shishikura M, Ozaki A. Synergistic excitability plasticity in cerebellar functioning. FEBS J 2020; 287:4557-4593. [PMID: 32367676 DOI: 10.1111/febs.15355] [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: 01/06/2020] [Revised: 04/22/2020] [Accepted: 04/30/2020] [Indexed: 12/27/2022]
Abstract
The cerebellum, a universal processor for sensory acquisition and internal models, and its association with synaptic and nonsynaptic plasticity have been envisioned as the biological correlates of learning, perception, and even thought. Indeed, the cerebellum is no longer considered merely as the locus of motor coordination and its learning. Here, we introduce the mechanisms underlying the induction of multiple types of plasticity in cerebellar circuit and give an overview focusing on the plasticity of nonsynaptic intrinsic excitability. The discovery of long-term potentiation of synaptic responsiveness in hippocampal neurons led investigations into changes of their intrinsic excitability. This activity-dependent potentiation of neuronal excitability is distinct from that of synaptic efficacy. Systematic examination of excitability plasticity has indicated that the modulation of various types of Ca2+ - and voltage-dependent K+ channels underlies the phenomenon, which is also triggered by immune activity. Intrinsic plasticity is expressed specifically on dendrites and modifies the integrative processing and filtering effect. In Purkinje cells, modulation of the discordance of synaptic current on soma and dendrite suggested a novel type of cellular learning mechanism. This property enables a plausible synergy between synaptic efficacy and intrinsic excitability, by amplifying electrical conductivity and influencing the polarity of bidirectional synaptic plasticity. Furthermore, the induction of intrinsic plasticity in the cerebellum correlates with motor performance and cognitive processes, through functional connections from the cerebellar nuclei to neocortex and associated regions: for example, thalamus and midbrain. Taken together, recent advances in neuroscience have begun to shed light on the complex functioning of nonsynaptic excitability and the synergy.
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Affiliation(s)
- Gen Ohtsuki
- The Hakubi Center for Advanced Research, Kyoto University, Japan.,Department of Biophysics, Kyoto University Graduate School of Science, Japan.,Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Japan
| | - Mari Shishikura
- Department of Biophysics, Kyoto University Graduate School of Science, Japan
| | - Akitoshi Ozaki
- Department of Biophysics, Kyoto University Graduate School of Science, Japan
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7
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Destabilization of light NREM sleep by thalamic PLCβ4 deletion impairs sleep-dependent memory consolidation. Sci Rep 2020; 10:8813. [PMID: 32483199 PMCID: PMC7264240 DOI: 10.1038/s41598-020-64377-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 04/15/2020] [Indexed: 01/20/2023] Open
Abstract
Sleep abnormality often accompanies the impairment of cognitive function. Both rapid eye movement (REM) and non-REM (NREM) sleep have associated with improved memory performance. However, the role of composition in NREM sleep, consisting of light and deep NREM, for memory formation is not fully understood. We investigated how the dynamics of NREM sleep states influence memory consolidation. Thalamocortical (TC) neuron-specific phospholipase C β4 (PLCβ4) knockout (KO) increased the total duration of NREM sleep, consisting of destabilized light NREM and stabilized deep NREM. Surprisingly, the longer NREM sleep did not improve memory consolidation but rather impaired it in TC-specific PLCβ4 KO mice. Memory function was positively correlated with the stability of light NREM and spindle activity occurring in maintained light NREM period. Our study suggests that a single molecule, PLCβ4, in TC neurons is critical for tuning the NREM sleep states and thus affects sleep-dependent memory formation.
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8
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Ohtsuki G. Modification of Synaptic-Input Clustering by Intrinsic Excitability Plasticity on Cerebellar Purkinje Cell Dendrites. J Neurosci 2020; 40:267-282. [PMID: 31754008 PMCID: PMC6948944 DOI: 10.1523/jneurosci.3211-18.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 10/08/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
The role of dendrites in the integration of widespread synaptic activity has been studied in experiments and theories (Johnston et al., 1996; Magee, 2007). However, whether the conduction of synaptic currents from dendrites to the soma depends on excitability of those dendritic branches is unclear. How modulation of the branch excitability affects the conduction of synaptic inputs and their selection on dendrites is also elusive. Here, I performed simultaneous voltage-clamp recordings from the soma and dendrites of single cerebellar Purkinje neurons in male Sprague-Dawley rats and analyzed the relationship between spontaneous EPSCs on both sides. I found that EPSCs on distal dendrites have a salient discordance in amplitude compared with those on the soma. Furthermore, individual ratios of the EPSC concurrently recorded on the soma and dendrites were not unique, but discrete, suggesting the occurrence of various attenuations in different paths of dendritic branches to the soma. The obtained data and simulations indicate several distinct groups (4.5 ± 0.3, n = 22 somatodendritic recordings) of co-occurred synaptic inputs in Purkinje cell dendrites. This clustering of synaptic currents was suggested to emerge at farther distances than the secondary bifurcations. Finally, ratios of the co-EPSCs were uniformly distributed after either intrinsic plasticity induction or SK-channel blockade. Overall, results suggest that in Purkinje cells the excitability along the dendrite processes modulates the conduction of EPSCs and makes active inputs heterogeneous through SK channel activity, intrinsic plasticity, and dendritic branching. These properties of dendrites may confer branch-specific computational power to neurons.SIGNIFICANCE STATEMENT I have previously studied the "non-synaptic" plasticity of the intrinsic excitability in the cerebellar Purkinje cells (Belmeguenai et al., 2010), and branch-specific increase of intrinsic excitability of the dendrites (Ohtsuki et al., 2012b; Ohtsuki and Hansel, 2018) through the downregulation of SK (small conductance Ca2+-activated K+) channels. In this study, I show that a dendritic filtering of synaptic electroconductivity is heterogeneous among the branches on distal dendrites and that the increase in the dendritic excitability accompanied with the intrinsic plasticity alters a state with the heterogeneity to a globally excitable state in Purkinje neurons. My findings propose a new learning model relying on the intrinsic excitability plasticity of the dendritic branch fields.
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Affiliation(s)
- Gen Ohtsuki
- The Hakubi Center for Advanced Research, Kyoto University, Yoshida, Sakyo-ward, Kyoto 606-8501, Japan, and
- Department of Biophysics, Kyoto University Graduate School of Science, Kitashirakawa-Oiwake-cho, Sakyo-ward, Kyoto 606-8224, Japan
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9
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Grasselli G, Boele HJ, Titley HK, Bradford N, van Beers L, Jay L, Beekhof GC, Busch SE, De Zeeuw CI, Schonewille M, Hansel C. SK2 channels in cerebellar Purkinje cells contribute to excitability modulation in motor-learning-specific memory traces. PLoS Biol 2020; 18:e3000596. [PMID: 31905212 PMCID: PMC6964916 DOI: 10.1371/journal.pbio.3000596] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 01/16/2020] [Accepted: 12/19/2019] [Indexed: 01/05/2023] Open
Abstract
Neurons store information by changing synaptic input weights. In addition, they can adjust their membrane excitability to alter spike output. Here, we demonstrate a role of such "intrinsic plasticity" in behavioral learning in a mouse model that allows us to detect specific consequences of absent excitability modulation. Mice with a Purkinje-cell-specific knockout (KO) of the calcium-activated K+ channel SK2 (L7-SK2) show intact vestibulo-ocular reflex (VOR) gain adaptation but impaired eyeblink conditioning (EBC), which relies on the ability to establish associations between stimuli, with the eyelid closure itself depending on a transient suppression of spike firing. In these mice, the intrinsic plasticity of Purkinje cells is prevented without affecting long-term depression or potentiation at their parallel fiber (PF) input. In contrast to the typical spike pattern of EBC-supporting zebrin-negative Purkinje cells, L7-SK2 neurons show reduced background spiking but enhanced excitability. Thus, SK2 plasticity and excitability modulation are essential for specific forms of motor learning.
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Affiliation(s)
- Giorgio Grasselli
- Department of Neurobiology, University of Chicago, Chicago, Illinois, United States of America
| | - Henk-Jan Boele
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Heather K. Titley
- Department of Neurobiology, University of Chicago, Chicago, Illinois, United States of America
| | - Nora Bradford
- Department of Neurobiology, University of Chicago, Chicago, Illinois, United States of America
| | - Lisa van Beers
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Lindsey Jay
- Department of Neurobiology, University of Chicago, Chicago, Illinois, United States of America
| | - Gerco C. Beekhof
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Silas E. Busch
- Department of Neurobiology, University of Chicago, Chicago, Illinois, United States of America
| | - Chris I. De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience, Royal Academy of Sciences, Amsterdam, The Netherlands
| | | | - Christian Hansel
- Department of Neurobiology, University of Chicago, Chicago, Illinois, United States of America
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10
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Changes in cerebellar intrinsic neuronal excitability and synaptic plasticity result from eyeblink conditioning. Neurobiol Learn Mem 2019; 166:107094. [PMID: 31542329 DOI: 10.1016/j.nlm.2019.107094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/27/2019] [Accepted: 09/16/2019] [Indexed: 12/21/2022]
Abstract
There is a long history of research documenting plasticity in the cerebellum as well as the role of the cerebellum in learning and memory. Recordings in slices of cerebellum have provided evidence of long-term depression and long-term potentiation at several excitatory and inhibitory synapses. Lesions and recordings show the cerebellum is crucial for eyeblink conditioning and it appears changes in both synaptic and membrane plasticity are involved. In addition to its role in fine motor control, there is growing consensus that the cerebellum is crucial for perceptual, cognitive, and emotional functions. In the current review, we explore the evidence that eyeblink conditioning results in significant changes in intrinsic membrane excitability as well as synaptic plasticity in Purkinje cells of the cerebellar cortex in rabbits and changes in intrinsic membrane excitability in principal neurons of the deep cerebellar nuclei in rats.
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11
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Izumisawa Y, Tanaka-Yamamoto K, Ciriello J, Kitamura N, Shibuya I. Persistent cytosolic Ca 2+ increase induced by angiotensin II at nanomolar concentrations in acutely dissociated subfornical organ (SFO) neurons of rats. Brain Res 2019; 1718:137-147. [PMID: 31085158 DOI: 10.1016/j.brainres.2019.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/23/2019] [Accepted: 05/11/2019] [Indexed: 10/26/2022]
Abstract
It is known that angiotensin II (AII) is sensed by subfornical organ (SFO) to induce drinking behaviors and autonomic changes. AII at picomolar concentrations have been shown to induce Ca2+ oscillations and increase in the amplitude and frequency of spontaneous Ca2+ oscillations in SFO neurons. The present study was conducted to examine effects of nanomolar concentrations of AII using the Fura-2 Ca2+-imaging technique in acutely dissociated SFO neurons. AII at nanomolar concentrations induced an initial [Ca2+]i peak followed by a persistent [Ca2+]i increase lasting for longer than 1 hour. By contrast, [Ca2+]i responses to 50 mM K+, maximally effective concentrations of glutamate, carbachol, and vasopressin, and AII given at picomolar concentrations returned to the basal level within 20 min. The AII-induced [Ca2+]i increase was blocked by the AT1 antagonist losartan. However, losartan had no effect when added during the persistent phase. The persistent phase was suppressed by extracellular Ca2+ removal, significantly inhibited by blockers of L and P/Q type Ca2+ channels , but unaffected by inhibition of Ca2+ store Ca2+ ATPase. The persistent phase was reversibly suppressed by GABA and inhibited by CaMK and PKC inhibitors. These results suggest that the persistent [Ca2+]i increase evoked by nanomolar concentrations of AII is initiated by AT1 receptor activation and maintained by Ca2+ entry mechanisms in part through L and P/Q type Ca2+ channels, and that CaMK and PKC are involved in this process. The persistent [Ca2+]i increase induced by AII at high pathophysiological levels may have a significant role in altering SFO neuronal functions.
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Affiliation(s)
- Yu Izumisawa
- Department of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-0945, Japan
| | - Keiko Tanaka-Yamamoto
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
| | - John Ciriello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Naoki Kitamura
- Department of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-0945, Japan
| | - Izumi Shibuya
- Department of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-0945, Japan.
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12
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Shim HG, Jang SS, Kim SH, Hwang EM, Min JO, Kim HY, Kim YS, Ryu C, Chung G, Kim Y, Yoon BE, Kim SJ. TNF-α increases the intrinsic excitability of cerebellar Purkinje cells through elevating glutamate release in Bergmann Glia. Sci Rep 2018; 8:11589. [PMID: 30072733 PMCID: PMC6072779 DOI: 10.1038/s41598-018-29786-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 07/18/2018] [Indexed: 11/17/2022] Open
Abstract
For decades, the glial function has been highlighted not only as the ‘structural glue’, but also as an ‘active participant’ in neural circuits. Here, we suggest that tumor necrosis factor α (TNF-α), a key inflammatory cytokine, alters the neural activity of the cerebellar Purkinje cells (PCs) by facilitating gliotransmission in the juvenile male rat cerebellum. A bath application of TNF-α (100 ng/ml) in acute cerebellar slices elevates spiking activity of PCs with no alterations in the regularity of PC firings. Interestingly, the effect of TNF-α on the intrinsic excitability of PCs was abolished under a condition in which the type1 TNF receptor (TNFR1) in Bergmann glia (BG) was genetically suppressed by viral delivery of an adeno-associated virus (AAV) containing TNFR1-shRNA. In addition, we measured the concentration of glutamate derived from dissociated cerebellar cortical astrocyte cultures treated with TNF-α and observed a progressive increase of glutamate in a time-dependent manner. We hypothesised that TNF-α-induced elevation of glutamate from BGs enveloping the synaptic cleft may directly activate metabotropic glutamate receptor1 (mGluR1). Pharmacological inhibition of mGluR1, indeed, prevented the TNF-α-mediated elevation of the intrinsic excitability in PCs. Taken together, our study reveals that TNF-α triggers glutamate release in BG, thereby increasing the intrinsic excitability of cerebellar PCs in a mGluR1-dependent manner.
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Affiliation(s)
- Hyun Geun Shim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Sung-Soo Jang
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Seung Ha Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Korea
| | - Joo Ok Min
- Department of Molecular biology, Dankook University, Chungnam, Korea
| | - Hye Yun Kim
- Department of Pharmacy and Integrated Science and Engineering Division, Yonsei University, Incheon, Korea
| | - Yoo Sung Kim
- Department of Molecular biology, Dankook University, Chungnam, Korea
| | - Changhyeon Ryu
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Geehoon Chung
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Brain and Cognitive Science, College of Science, Seoul National University, Seoul, Korea
| | - YoungSoo Kim
- Department of Pharmacy and Integrated Science and Engineering Division, Yonsei University, Incheon, Korea
| | - Bo-Eun Yoon
- Department of Molecular biology, Dankook University, Chungnam, Korea
| | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea. .,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea. .,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea.
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Perkins EM, Clarkson YL, Suminaite D, Lyndon AR, Tanaka K, Rothstein JD, Skehel PA, Wyllie DJA, Jackson M. Loss of cerebellar glutamate transporters EAAT4 and GLAST differentially affects the spontaneous firing pattern and survival of Purkinje cells. Hum Mol Genet 2018; 27:2614-2627. [PMID: 29741614 PMCID: PMC6049029 DOI: 10.1093/hmg/ddy169] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/30/2018] [Accepted: 05/01/2018] [Indexed: 12/20/2022] Open
Abstract
Loss of excitatory amino acid transporters (EAATs) has been implicated in a number of human diseases including spinocerebellar ataxias, Alzhiemer's disease and motor neuron disease. EAAT4 and GLAST/EAAT1 are the two predominant EAATs responsible for maintaining low extracellular glutamate levels and preventing neurotoxicity in the cerebellum, the brain region essential for motor control. Here using genetically modified mice we identify new critical roles for EAAT4 and GLAST/EAAT1 as modulators of Purkinje cell (PC) spontaneous firing patterns. We show high EAAT4 levels, by limiting mGluR1 signalling, are essential in constraining inherently heterogeneous firing of zebrin-positive PCs. Moreover mGluR1 antagonists were found to restore regular spontaneous PC activity and motor behaviour in EAAT4 knockout mice. In contrast, GLAST/EAAT1 expression is required to sustain normal spontaneous simple spike activity in low EAAT4 expressing (zebrin-negative) PCs by restricting NMDA receptor activation. Blockade of NMDA receptor activity restores spontaneous activity in zebrin-negative PCs of GLAST knockout mice and furthermore alleviates motor deficits. In addition both transporters have differential effects on PC survival, with zebrin-negative PCs more vulnerable to loss of GLAST/EAAT1 and zebrin-positive PCs more vulnerable to loss of EAAT4. These findings reveal that glutamate transporter dysfunction through elevated extracellular glutamate and the aberrant activation of extrasynaptic receptors can disrupt cerebellar output by altering spontaneous PC firing. This expands our understanding of disease mechanisms in cerebellar ataxias and establishes EAATs as targets for restoring homeostasis in a variety of neurological diseases where altered cerebellar output is now thought to play a key role in pathogenesis.
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Affiliation(s)
- Emma M Perkins
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Yvonne L Clarkson
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Daumante Suminaite
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Alastair R Lyndon
- School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, John Muir Building, Riccarton, Edinburgh, UK
| | - Kohichi Tanaka
- Laboratory of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-Ku, Tokyo, Japan
| | - Jeffrey D Rothstein
- Department of Neurology and Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Paul A Skehel
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - David J A Wyllie
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Mandy Jackson
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
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14
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Shim HG, Lee YS, Kim SJ. The Emerging Concept of Intrinsic Plasticity: Activity-dependent Modulation of Intrinsic Excitability in Cerebellar Purkinje Cells and Motor Learning. Exp Neurobiol 2018; 27:139-154. [PMID: 30022866 PMCID: PMC6050419 DOI: 10.5607/en.2018.27.3.139] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 12/15/2022] Open
Abstract
What is memory? How does the brain process the sensory information and modify an organism's behavior? Many neuroscientists have focused on the activity- and experience-dependent modifications of synaptic functions in order to solve these fundamental questions in neuroscience. Recently, the plasticity of intrinsic excitability (called intrinsic plasticity) has emerged as an important element for information processing and storage in the brain. As the cerebellar Purkinje cells are the sole output neurons in the cerebellar cortex and the information is conveyed from a neuron to its relay neurons by forms of action potential firing, the modulation of the intrinsic firing activity may play a critical role in the cerebellar learning. Many voltage-gated and/or Ca2+-activated ion channels are involved in shaping the spiking output as well as integrating synaptic inputs to finely tune the cerebellar output. Recent studies suggested that the modulation of the intrinsic excitability and its plasticity in the cerebellar Purkinje cells might function as an integrator for information processing and memory formation. Moreover, the intrinsic plasticity might also determine the strength of connectivity to the sub-cortical areas such as deep cerebellar nuclei and vestibular nuclei to trigger the consolidation of the cerebellar-dependent memory by transferring the information.
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Affiliation(s)
- Hyun Geun Shim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Yong-Seok Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080, Korea
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15
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Long-Term Depression of Intrinsic Excitability Accompanied by Synaptic Depression in Cerebellar Purkinje Cells. J Neurosci 2017; 37:5659-5669. [PMID: 28495974 DOI: 10.1523/jneurosci.3464-16.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 04/11/2017] [Accepted: 04/26/2017] [Indexed: 11/21/2022] Open
Abstract
Long-term depression (LTD) at the parallel fiber (PF)-to-cerebellar Purkinje cell (PC) synapse is implicated in the output of PCs, the sole output of the cerebellar cortex. In addition to synaptic plasticity, intrinsic excitability is also one of the components that determines PC output. Although long-term potentiation of intrinsic excitability (LTP-IE) has been suggested, it has yet to be investigated how PF-PC LTD modifies intrinsic excitability of PCs. Here, we show that pairing of the PF and climbing fiber (CF) for PF-PC LTD induction evokes LTD-IE in cerebellar PCs from male C57BL/6 mice. Interestingly, this intrinsic plasticity showed different kinetics from synaptic plasticity, but both forms of plasticity share Ca2+ signaling and protein kinase C pathway as their underlying mechanism. Although small-conductance Ca2+-activated K+ channels play important roles in LTP-IE, no direct implication has been found. After PF-PC LTD induction, neither the temporal summation of dendritic EPSP nor the power of spike frequency adaptation is changed, indicating that cerebellar LTD executes the information processing in a quantitative way without quality changes of synaptic integration and generation of output signals. Our results suggest that LTD-IE may have a synergistic effect with synaptic depression on the total net output of neurons by amplifying the modification of PF synaptic transmission.SIGNIFICANCE STATEMENT Although the output of Purkinje cells (PCs) is a critical component of cerebellum-dependent learning and memory, the changes of PC excitability when synaptic LTD occurs are unclear. Here, we show that the induction of PF-PC LTD evokes LTD-IE in PCs. Our observation complements previous intrinsic plasticity phenomenon of long-term potentiation of intrinsic excitability (LTP-IE), providing evidence for the idea that intrinsic plasticity has bidirectionality as synaptic plasticity. LTD-IE occurs together with synaptic LTD and both phenomena are dependent on the Ca2+ signaling pathway. Furthermore, our findings raise the prospect that this synaptic and intrinsic plasticity acts synergistically in PCs to modify neuronal activity in the same direction when learning occurs.
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16
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Lv X, Dickerson JW, Rook JM, Lindsley CW, Conn PJ, Xiang Z. M 1 muscarinic activation induces long-lasting increase in intrinsic excitability of striatal projection neurons. Neuropharmacology 2017; 118:209-222. [PMID: 28336323 DOI: 10.1016/j.neuropharm.2017.03.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 02/20/2017] [Accepted: 03/15/2017] [Indexed: 01/11/2023]
Abstract
The dorsolateral striatum is critically involved in movement control and motor learning. Striatal function is regulated by a variety of neuromodulators including acetylcholine. Previous studies have shown that cholinergic activation excites striatal principal projection neurons, medium spiny neurons (MSNs), and this action is mediated by muscarinic acetylcholine subtype 1 receptors (M1) through modulating multiple potassium channels. In the present study, we used electrophysiology techniques in conjunction with optogenetic and pharmacological tools to determine the long-term effects of striatal cholinergic activation on MSN intrinsic excitability. A transient increase in acetylcholine release in the striatum by optogenetic stimulation resulted in a long-lasting increase in excitability of MSNs, which was associated with hyperpolarizing shift of action potential threshold and decrease in afterhyperpolarization (AHP) amplitude, leading to an increase in probability of EPSP-action potential coupling. The M1 selective antagonist VU0255035 prevented, while the M1 selective positive allosteric modulator (PAM) VU0453595 potentiated the cholinergic activation-induced persistent increase in MSN intrinsic excitability, suggesting that M1 receptors are critically involved in the induction of this long-lasting response. This M1 receptor-dependent long-lasting change in MSN intrinsic excitability could have significant impact on striatal processing and might provide a novel mechanism underlying cholinergic regulation of the striatum-dependent motor learning and cognitive function. Consistent with this, behavioral studies indicate that potentiation of M1 receptor signaling by VU0453595 enhanced performance of mice in cue-dependent water-based T-maze, a dorsolateral striatum-dependent learning task.
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Affiliation(s)
- Xiaohui Lv
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Jonathan W Dickerson
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Jerri M Rook
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Zixiu Xiang
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA.
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