1
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Jones SP, O'Neill N, Carpenter JC, Muggeo S, Colasante G, Kullmann DM, Lignani G. Early developmental alterations of CA1 pyramidal cells in Dravet syndrome. Neurobiol Dis 2024; 201:106688. [PMID: 39368670 DOI: 10.1016/j.nbd.2024.106688] [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: 04/19/2024] [Revised: 08/21/2024] [Accepted: 09/29/2024] [Indexed: 10/07/2024] Open
Abstract
Dravet Syndrome (DS) is most often caused by heterozygous loss-of-function mutations in the voltage-gated sodium channel gene SCN1A (Nav1.1), resulting in severe epilepsy and neurodevelopmental impairment thought to be cause by reduced interneuron excitability. However, recent studies in mouse models suggest that interneuron dysfunction alone does not completely explain all the cellular and network impairments seen in DS. Here, we investigated the development of the intrinsic, synaptic, and network properties of CA1 pyramidal cells in a DS model prior to the appearance of overt seizures. We report that CA1 pyramidal cell development is altered by heterozygous reduction of Scn1a, and propose that this is explained by a period of reduced intrinsic excitability in early postnatal life, during which Scn1a is normally expressed in hippocampal pyramidal cells. We also use a novel ex vivo model of homeostatic plasticity to show an instability in homeostatic response during DS epileptogenesis. This study provides evidence for the early effects of Scn1a haploinsufficiency in pyramidal cells in contributing to the pathophysiology of DS.
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Affiliation(s)
- Steffan P Jones
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Nathanael O'Neill
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Jenna C Carpenter
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Sharon Muggeo
- San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milan, Italy
| | - Gaia Colasante
- San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milan, Italy
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK.
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2
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Piazza MK, Kavalali ET, Monteggia LM. Ketamine induced synaptic plasticity operates independently of long-term potentiation. Neuropsychopharmacology 2024; 49:1758-1766. [PMID: 38898206 PMCID: PMC11399243 DOI: 10.1038/s41386-024-01895-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/11/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024]
Abstract
Synaptic plasticity occurs via multiple mechanisms to regulate synaptic efficacy. Homeostatic and Hebbian plasticity are two such mechanisms by which neuronal synapses can be altered. Although these two processes are mechanistically distinct, they converge on downstream regulation of AMPA receptor activity to modify glutamatergic neurotransmission. However, much remains to be explored regarding how these two prominent forms of plasticity interact. Ketamine, a rapidly acting antidepressant, increases glutamatergic transmission via pharmacologically-induced homeostatic plasticity. Here, we demonstrate that Hebbian plasticity mechanisms are still intact in synapses that have undergone homeostatic scaling by ketamine after either systemic injection or perfusion onto hippocampal brain slices. We also investigated this relationship in the context of stress induced by chronic exposure to corticosterone (CORT) to better model the circumstances under which ketamine may be used as an antidepressant. We found that CORT induced an anhedonia-like behavioral phenotype in mice but did not impair long-term potentiation (LTP) induction. Furthermore, corticosterone exposure does not impact the intersection of homeostatic and Hebbian plasticity mechanisms, as synapses from CORT-exposed mice also demonstrated intact ketamine-induced plasticity and LTP in succession. These results provide a mechanistic explanation for how ketamine used for the treatment of depression does not impair the integrity of learning and memory processes encoded by mechanisms such as LTP.
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Affiliation(s)
- Michelle K Piazza
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37240-7933, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37240-7933, USA
| | - Ege T Kavalali
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37240-7933, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37240-7933, USA
| | - Lisa M Monteggia
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37240-7933, USA.
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37240-7933, USA.
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3
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Zhou YS, Tao HB, Lv SS, Liang KQ, Shi WY, Liu KY, Li YY, Chen LY, Zhou L, Yin SJ, Zhao QR. Effects of Kv1.3 knockout on pyramidal neuron excitability and synaptic plasticity in piriform cortex of mice. Acta Pharmacol Sin 2024; 45:2045-2060. [PMID: 38862816 PMCID: PMC11420205 DOI: 10.1038/s41401-024-01275-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 03/24/2024] [Indexed: 06/13/2024] Open
Abstract
Kv1.3 belongs to the voltage-gated potassium (Kv) channel family, which is widely expressed in the central nervous system and associated with a variety of neuropsychiatric disorders. Kv1.3 is highly expressed in the olfactory bulb and piriform cortex and involved in the process of odor perception and nutrient metabolism in animals. Previous studies have explored the function of Kv1.3 in olfactory bulb, while the role of Kv1.3 in piriform cortex was less known. In this study, we investigated the neuronal changes of piriform cortex and feeding behavior after smell stimulation, thus revealing a link between the olfactory sensation and body weight in Kv1.3 KO mice. Coronal slices including the anterior piriform cortex were prepared, whole-cell recording and Ca2+ imaging of pyramidal neurons were conducted. We showed that the firing frequency evoked by depolarization pulses and Ca2+ influx evoked by high K+ solution were significantly increased in pyramidal neurons of Kv1.3 knockout (KO) mice compared to WT mice. Western blotting and immunofluorescence analyses revealed that the downstream signaling molecules CaMKII and PKCα were activated in piriform cortex of Kv1.3 KO mice. Pyramidal neurons in Kv1.3 KO mice exhibited significantly reduced paired-pulse ratio and increased presynaptic Cav2.1 expression, proving that the presynaptic vesicle release might be elevated by Ca2+ influx. Using Golgi staining, we found significantly increased dendritic spine density of pyramidal neurons in Kv1.3 KO mice, supporting the stronger postsynaptic responses in these neurons. In olfactory recognition and feeding behavior tests, we showed that Kv1.3 conditional knockout or cannula injection of 5-(4-phenoxybutoxy) psoralen, a Kv1.3 channel blocker, in piriform cortex both elevated the olfactory recognition index and altered the feeding behavior in mice. In summary, Kv1.3 is a key molecule in regulating neuronal activity of the piriform cortex, which may lay a foundation for the treatment of diseases related to piriform cortex and olfactory detection.
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Affiliation(s)
- Yong-Sheng Zhou
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Hao-Bo Tao
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Si-Si Lv
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Ke-Qin Liang
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Wen-Yi Shi
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Ke-Yi Liu
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Yun-Yun Li
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Lv-Yi Chen
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Ling Zhou
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Shi-Jin Yin
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China.
| | - Qian-Ru Zhao
- Department of Chemical Biology, School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China.
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4
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Aghi K, Schultz R, Newman ZL, Mendonça P, Li R, Bakshinska D, Isacoff EY. Synapse-to-synapse plasticity variability balanced to generate input-wide constancy of transmitter release. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.11.612562. [PMID: 39314438 PMCID: PMC11419063 DOI: 10.1101/2024.09.11.612562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Basal synaptic strength can vary greatly between synapses formed by an individual neuron because of diverse probabilities of action potential (AP) evoked transmitter release ( Pr ). Optical quantal analysis on large numbers of identified Drosophila larval glutamatergic synapses shows that short-term plasticity (STP) also varies greatly between synapses made by an individual type I motor neuron (MN) onto a single body wall muscle. Synapses with high and low P r and different forms and level of STP have a random spatial distribution in the MN nerve terminal, and ones with very different properties can be located within 200 nm of one other. While synapses start off with widely diverse basal P r at low MN AP firing frequency and change P r differentially when MN firing frequency increases, the overall distribution of P r remains remarkably constant due to a balance between the numbers of synapses that facilitate and depress as well as their degree of change and basal synaptic weights. This constancy in transmitter release can ensure robustness across changing behavioral conditions.
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5
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Chien C, He K, Perry S, Tchitchkan E, Han Y, Li X, Dickman D. Distinct input-specific mechanisms enable presynaptic homeostatic plasticity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.10.612361. [PMID: 39314403 PMCID: PMC11419068 DOI: 10.1101/2024.09.10.612361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Synapses are endowed with the flexibility to change through experience, but must be sufficiently stable to last a lifetime. This tension is illustrated at the Drosophila neuromuscular junction (NMJ), where two motor inputs that differ in structural and functional properties co-innervate most muscles to coordinate locomotion. To stabilize NMJ activity, motor neurons augment neurotransmitter release following diminished postsynaptic glutamate receptor functionality, termed presynaptic homeostatic potentiation (PHP). How these distinct inputs contribute to PHP plasticity remains enigmatic. We have used a botulinum neurotoxin to selectively silence each input and resolve their roles in PHP, demonstrating that PHP is input-specific: Chronic (genetic) PHP selectively targets the tonic MN-Ib, where active zone remodeling enhances Ca2+ influx to promote increased glutamate release. In contrast, acute (pharmacological) PHP selectively increases vesicle pools to potentiate phasic MN-Is. Thus, distinct homeostatic modulations in active zone nanoarchitecture, vesicle pools, and Ca2+ influx collaborate to enable input-specific PHP expression.
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Affiliation(s)
- Chun Chien
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
- USC Neuroscience Graduate Program
| | - Kaikai He
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
- USC Neuroscience Graduate Program
| | - Sarah Perry
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
| | - Elizabeth Tchitchkan
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
| | - Yifu Han
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
- USC Neuroscience Graduate Program
| | - Xiling Li
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
- USC Neuroscience Graduate Program
| | - Dion Dickman
- University of Southern California, Department of Neurobiology, Los Angeles, CA USA
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6
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Koster KP, Green WN. Editorial: Role of protein palmitoylation in synaptic plasticity and neuronal differentiation, volume II. Front Synaptic Neurosci 2024; 16:1473989. [PMID: 39319198 PMCID: PMC11420002 DOI: 10.3389/fnsyn.2024.1473989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Accepted: 08/26/2024] [Indexed: 09/26/2024] Open
Affiliation(s)
- Kevin P. Koster
- Department of Neurobiology, University of Chicago, Chicago, IL, United States
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7
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Bridi MCD, Hong S, Severin D, Moreno C, Contreras A, Kirkwood A. Blockade of GluN2B-Containing NMDA Receptors Prevents Potentiation and Depression of Responses during Ocular Dominance Plasticity. J Neurosci 2024; 44:e0021232024. [PMID: 39117456 PMCID: PMC11376332 DOI: 10.1523/jneurosci.0021-23.2024] [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: 12/14/2022] [Revised: 07/03/2024] [Accepted: 07/27/2024] [Indexed: 08/10/2024] Open
Abstract
Monocular deprivation (MD) causes an initial decrease in synaptic responses to the deprived eye in juvenile mouse primary visual cortex (V1) through Hebbian long-term depression (LTD). This is followed by a homeostatic increase, which has been attributed either to synaptic scaling or to a slide threshold for Hebbian long-term potentiation (LTP) rather than scaling. We therefore asked in mice of all sexes whether the homeostatic increase during MD requires GluN2B-containing NMDA receptor activity, which is required to slide the plasticity threshold but not for synaptic scaling. Selective GluN2B blockade from 2-6 d after monocular lid suture prevented the homeostatic increase in miniature excitatory postsynaptic current (mEPSC) amplitude in monocular V1 of acute slices and prevented the increase in visually evoked responses in binocular V1 in vivo. The decrease in mEPSC amplitude and visually evoked responses during the first 2 d of MD also required GluN2B activity. Together, these results support the idea that GluN2B-containing NMDA receptors first play a role in LTD immediately following eye closure and then promote homeostasis during prolonged MD by sliding the plasticity threshold in favor of LTP.
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Affiliation(s)
- Michelle C D Bridi
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Su Hong
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Daniel Severin
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Cristian Moreno
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Altagracia Contreras
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Alfredo Kirkwood
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
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8
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Lakhani A, Gonzalez-Islas C, Sabra Z, Au Yong N, Wenner P. Homeostatic Regulation of Spike Rate within Bursts in Two Distinct Preparations. eNeuro 2024; 11:ENEURO.0259-24.2024. [PMID: 39160070 PMCID: PMC11391507 DOI: 10.1523/eneuro.0259-24.2024] [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: 06/10/2024] [Revised: 07/26/2024] [Accepted: 08/05/2024] [Indexed: 08/21/2024] Open
Abstract
Homeostatic plasticity represents a set of mechanisms thought to stabilize some function of neural activity. Here, we identified the specific features of cellular or network activity that were maintained after the perturbation of GABAergic blockade in two different systems: mouse cortical neuronal cultures where GABA is inhibitory and motoneurons in the isolated embryonic chick spinal cord where GABA is excitatory (males and females combined in both systems). We conducted a comprehensive analysis of various spiking activity characteristics following GABAergic blockade. We observed significant variability in many features after blocking GABAA receptors (e.g., burst frequency, burst duration, overall spike frequency in culture). These results are consistent with the idea that neuronal networks achieve activity goals using different strategies (degeneracy). On the other hand, some features were consistently altered after receptor blockade in the spinal cord preparation (e.g., overall spike frequency). Regardless, these features did not express strong homeostatic recoveries when tracking individual preparations over time. One feature showed a consistent change and homeostatic recovery following GABAA receptor block. We found that spike rate within a burst (SRWB) increased after receptor block in both the spinal cord preparation and cortical cultures and then returned to baseline within hours. These changes in SRWB occurred at both single cell and population levels. Our findings indicate that the network prioritizes the burst spike rate, which appears to be a variable under tight homeostatic regulation. The result is consistent with the idea that networks can maintain an appropriate behavioral response in the face of challenges.
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Affiliation(s)
- Alishah Lakhani
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Carlos Gonzalez-Islas
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
- Doctorado en Ciencias Biológicas Universidad Autónoma de Tlaxcala, Tlaxcala 90070, México
| | - Zahraa Sabra
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Nicholas Au Yong
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Peter Wenner
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
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9
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McGregor JN, Farris CA, Ensley S, Schneider A, Fosque LJ, Wang C, Tilden EI, Liu Y, Tu J, Elmore H, Ronayne KD, Wessel R, Dyer EL, Bhaskaran-Nair K, Holtzman DM, Hengen KB. Failure in a population: Tauopathy disrupts homeostatic set-points in emergent dynamics despite stability in the constituent neurons. Neuron 2024:S0896-6273(24)00578-6. [PMID: 39241778 DOI: 10.1016/j.neuron.2024.08.006] [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: 09/06/2023] [Revised: 06/24/2024] [Accepted: 08/09/2024] [Indexed: 09/09/2024]
Abstract
Homeostatic regulation of neuronal activity is essential for robust computation; set-points, such as firing rate, are actively stabilized to compensate for perturbations. The disruption of brain function central to neurodegenerative disease likely arises from impairments of computationally essential set-points. Here, we systematically investigated the effects of tau-mediated neurodegeneration on all known set-points in neuronal activity. We continuously tracked hippocampal neuronal activity across the lifetime of a mouse model of tauopathy. We were unable to detect effects of disease in measures of single-neuron firing activity. By contrast, as tauopathy progressed, there was disruption of network-level neuronal activity, quantified by measuring neuronal pairwise interactions and criticality, a homeostatically controlled, ideal computational regime. Deviations in criticality correlated with symptoms, predicted underlying anatomical pathology, occurred in a sleep-wake-dependent manner, and could be used to reliably classify an animal's genotype. This work illustrates how neurodegeneration may disrupt the computational capacity of neurobiological systems.
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Affiliation(s)
- James N McGregor
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Clayton A Farris
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Sahara Ensley
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Aidan Schneider
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Leandro J Fosque
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Chao Wang
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in Saint Louis, St. Louis, MO, USA; Institute for Brain Science and Disease, Chongqing Medical University, Chongqing 400016, China
| | - Elizabeth I Tilden
- Department of Neuroscience, Washington University in Saint Louis, St. Louis, MO, USA
| | - Yuqi Liu
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Jianhong Tu
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Halla Elmore
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Keenan D Ronayne
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Ralf Wessel
- Department of Physics, Washington University in Saint Louis, St. Louis, MO, USA
| | - Eva L Dyer
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in Saint Louis, St. Louis, MO, USA
| | - Keith B Hengen
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA.
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10
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Xiong A, Richmond JE, Kim H. Presynaptic neurons self-tune by inversely coupling neurotransmitter release with the abundance of CaV2 voltage-gated Ca 2+ channels. Proc Natl Acad Sci U S A 2024; 121:e2404969121. [PMID: 39172783 PMCID: PMC11363341 DOI: 10.1073/pnas.2404969121] [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: 03/09/2024] [Accepted: 07/12/2024] [Indexed: 08/24/2024] Open
Abstract
The abundance of CaV2 voltage-gated calcium channels is linked to presynaptic homeostatic plasticity (PHP), a process that recalibrates synaptic strength to maintain the stability of neural circuits. However, the molecular and cellular mechanisms governing PHP and CaV2 channels are not completely understood. Here, we uncover a previously not described form of PHP in Caenorhabditis elegans, revealing an inverse regulatory relationship between the efficiency of neurotransmitter release and the abundance of UNC-2/CaV2 channels. Gain-of-function unc-2SL(S240L) mutants, which carry a mutation analogous to the one causing familial hemiplegic migraine type 1 in humans, showed markedly reduced channel abundance despite increased channel functionality. Reducing synaptic release in these unc-2SL(S240L) mutants restored channel levels to those observed in wild-type animals. Conversely, loss-of-function unc-2DA(D726A) mutants, which harbor the D726A mutation in the channel pore, exhibited a marked increase in channel abundance. Enhancing synaptic release in unc-2DA mutants reversed this increase in channel levels. Importantly, this homeostatic regulation of UNC-2 channel levels is accompanied by the structural remodeling of the active zone (AZ); specifically, unc-2DA mutants, which exhibit increased channel abundance, showed parallel increases in select AZ proteins. Finally, our forward genetic screen revealed that WWP-1, a HECT family E3 ubiquitin ligase, is a key homeostatic mediator that removes UNC-2 from synapses. These findings highlight a self-tuning PHP regulating UNC-2/CaV2 channel abundance along with AZ reorganization, ensuring synaptic strength and stability.
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Affiliation(s)
- Ame Xiong
- Discipline of Cell Biology & Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Janet E. Richmond
- Department of Biological Sciences, University of Illinois, Chicago, IL60607
| | - Hongkyun Kim
- Discipline of Cell Biology & Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
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11
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Nair AG, Bollmohr N, Schökle L, Keim J, Melero JMM, Müller M. Presynaptic quantal size enhancement counteracts post-tetanic release depression. J Physiol 2024. [PMID: 39183664 DOI: 10.1113/jp286176] [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: 04/25/2024] [Accepted: 07/30/2024] [Indexed: 08/27/2024] Open
Abstract
Repetitive synaptic stimulation can induce different forms of synaptic plasticity but may also limit the robustness of synaptic transmission by exhausting key resources. Little is known about how synaptic transmission is stabilized after high-frequency stimulation. In the present study, we observed that tetanic stimulation of the Drosophila neuromuscular junction (NMJ) decreases quantal content, release-ready vesicle pool size and synaptic vesicle density for minutes after stimulation. This was accompanied by a pronounced increase in quantal size. Interestingly, action potential-evoked synaptic transmission remained largely unchanged. EPSC amplitude fluctuation analysis confirmed the post-tetanic increase in quantal size and the decrease in quantal content, suggesting that the quantal size increase counteracts release depression to maintain evoked transmission. The magnitude of the post-tetanic quantal size increase and release depression correlated with stimulation frequency and duration, indicating activity-dependent stabilization of synaptic transmission. The post-tetanic quantal size increase persisted after genetic ablation of the glutamate receptor subunits GluRIIA or GluRIIB, and glutamate receptor calcium permeability, as well as blockade of postsynaptic calcium channels. By contrast, it was strongly attenuated by pharmacological or presynaptic genetic perturbation of the GTPase dynamin. Similar observations were made after inhibition of the H+-ATPase, suggesting that the quantal size increase is presynaptically driven. Additionally, dynamin and H+-ATPase perturbation resulted in a post-tetanic decrease in evoked amplitudes. Finally, we observed an increase in synaptic vesicle diameter after tetanic stimulation. Thus, a presynaptically-driven quantal size increase, likely mediated by larger synaptic vesicles, counterbalances post-tetanic release depression, thereby conferring robustness to synaptic transmission on the minute time scale. KEY POINTS: Many synapses transmit robustly after sustained activity despite the limitation of key resources, such as release-ready synaptic vesicles. We report robust synaptic transmission after sustained high-frequency stimulation of the Drosophila neuromuscular junction despite a reduction in release-ready vesicle number. An increased postsynaptic response to individual vesicles, likely driven by an increase in vesicle size due to endocytosis defects, stabilizes synaptic efficacy for minutes after sustained activity. Our study provides novel insights into the mechanisms governing synaptic stability after sustained neural activity.
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Affiliation(s)
- Anu G Nair
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Present address: Roche Pharma Research and Early Development, Basel, Switzerland
| | - Nasrin Bollmohr
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich/ETH Zurich, Zurich, Switzerland
| | - Levin Schökle
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Jennifer Keim
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Present address: AbbVie AG, Cham, Switzerland
| | | | - Martin Müller
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich/ETH Zurich, Zurich, Switzerland
- University Research Priority Program (URPP), Adaptive Brain Circuits in Development and Learning (AdaBD), University of Zurich, Zurich, Switzerland
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12
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Karaba LA, Robinson HL, Harvey RE, Chen W, Fernandez-Ruiz A, Oliva A. A hippocampal circuit mechanism to balance memory reactivation during sleep. Science 2024; 385:738-743. [PMID: 39146421 PMCID: PMC11428313 DOI: 10.1126/science.ado5708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 06/14/2024] [Indexed: 08/17/2024]
Abstract
Memory consolidation involves the synchronous reactivation of hippocampal cells active during recent experience in sleep sharp-wave ripples (SWRs). How this increase in firing rates and synchrony after learning is counterbalanced to preserve network stability is not understood. We discovered a network event generated by an intrahippocampal circuit formed by a subset of CA2 pyramidal cells to cholecystokinin-expressing (CCK+) basket cells, which fire a barrage of action potentials ("BARR") during non-rapid eye movement sleep. CA1 neurons and assemblies that increased their activity during learning were reactivated during SWRs but inhibited during BARRs. The initial increase in reactivation during SWRs returned to baseline through sleep. This trend was abolished by silencing CCK+ basket cells during BARRs, resulting in higher synchrony of CA1 assemblies and impaired memory consolidation.
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Affiliation(s)
- Lindsay A Karaba
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Heath L Robinson
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Ryan E Harvey
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Weiwei Chen
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | | | - Azahara Oliva
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
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13
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Malkin J, O'Donnell C, Houghton CJ, Aitchison L. Signatures of Bayesian inference emerge from energy-efficient synapses. eLife 2024; 12:RP92595. [PMID: 39106188 PMCID: PMC11302983 DOI: 10.7554/elife.92595] [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] [Indexed: 08/09/2024] Open
Abstract
Biological synaptic transmission is unreliable, and this unreliability likely degrades neural circuit performance. While there are biophysical mechanisms that can increase reliability, for instance by increasing vesicle release probability, these mechanisms cost energy. We examined four such mechanisms along with the associated scaling of the energetic costs. We then embedded these energetic costs for reliability in artificial neural networks (ANNs) with trainable stochastic synapses, and trained these networks on standard image classification tasks. The resulting networks revealed a tradeoff between circuit performance and the energetic cost of synaptic reliability. Additionally, the optimised networks exhibited two testable predictions consistent with pre-existing experimental data. Specifically, synapses with lower variability tended to have (1) higher input firing rates and (2) lower learning rates. Surprisingly, these predictions also arise when synapse statistics are inferred through Bayesian inference. Indeed, we were able to find a formal, theoretical link between the performance-reliability cost tradeoff and Bayesian inference. This connection suggests two incompatible possibilities: evolution may have chanced upon a scheme for implementing Bayesian inference by optimising energy efficiency, or alternatively, energy-efficient synapses may display signatures of Bayesian inference without actually using Bayes to reason about uncertainty.
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Affiliation(s)
- James Malkin
- Faculty of Engineering, University of BristolBristolUnited Kingdom
| | - Cian O'Donnell
- Faculty of Engineering, University of BristolBristolUnited Kingdom
- Intelligent Systems Research Centre, School of Computing, Engineering, and Intelligent Systems, Ulster UniversityDerry/LondonderryUnited Kingdom
| | - Conor J Houghton
- Faculty of Engineering, University of BristolBristolUnited Kingdom
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14
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Wen W, Turrigiano GG. Keeping Your Brain in Balance: Homeostatic Regulation of Network Function. Annu Rev Neurosci 2024; 47:41-61. [PMID: 38382543 DOI: 10.1146/annurev-neuro-092523-110001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
To perform computations with the efficiency necessary for animal survival, neocortical microcircuits must be capable of reconfiguring in response to experience, while carefully regulating excitatory and inhibitory connectivity to maintain stable function. This dynamic fine-tuning is accomplished through a rich array of cellular homeostatic plasticity mechanisms that stabilize important cellular and network features such as firing rates, information flow, and sensory tuning properties. Further, these functional network properties can be stabilized by different forms of homeostatic plasticity, including mechanisms that target excitatory or inhibitory synapses, or that regulate intrinsic neuronal excitability. Here we discuss which aspects of neocortical circuit function are under homeostatic control, how this homeostasis is realized on the cellular and molecular levels, and the pathological consequences when circuit homeostasis is impaired. A remaining challenge is to elucidate how these diverse homeostatic mechanisms cooperate within complex circuits to enable them to be both flexible and stable.
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Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
| | - Gina G Turrigiano
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
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15
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Siegel JS, Subramanian S, Perry D, Kay BP, Gordon EM, Laumann TO, Reneau TR, Metcalf NV, Chacko RV, Gratton C, Horan C, Krimmel SR, Shimony JS, Schweiger JA, Wong DF, Bender DA, Scheidter KM, Whiting FI, Padawer-Curry JA, Shinohara RT, Chen Y, Moser J, Yacoub E, Nelson SM, Vizioli L, Fair DA, Lenze EJ, Carhart-Harris R, Raison CL, Raichle ME, Snyder AZ, Nicol GE, Dosenbach NUF. Psilocybin desynchronizes the human brain. Nature 2024; 632:131-138. [PMID: 39020167 PMCID: PMC11291293 DOI: 10.1038/s41586-024-07624-5] [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: 10/24/2023] [Accepted: 05/29/2024] [Indexed: 07/19/2024]
Abstract
A single dose of psilocybin, a psychedelic that acutely causes distortions of space-time perception and ego dissolution, produces rapid and persistent therapeutic effects in human clinical trials1-4. In animal models, psilocybin induces neuroplasticity in cortex and hippocampus5-8. It remains unclear how human brain network changes relate to subjective and lasting effects of psychedelics. Here we tracked individual-specific brain changes with longitudinal precision functional mapping (roughly 18 magnetic resonance imaging visits per participant). Healthy adults were tracked before, during and for 3 weeks after high-dose psilocybin (25 mg) and methylphenidate (40 mg), and brought back for an additional psilocybin dose 6-12 months later. Psilocybin massively disrupted functional connectivity (FC) in cortex and subcortex, acutely causing more than threefold greater change than methylphenidate. These FC changes were driven by brain desynchronization across spatial scales (areal, global), which dissolved network distinctions by reducing correlations within and anticorrelations between networks. Psilocybin-driven FC changes were strongest in the default mode network, which is connected to the anterior hippocampus and is thought to create our sense of space, time and self. Individual differences in FC changes were strongly linked to the subjective psychedelic experience. Performing a perceptual task reduced psilocybin-driven FC changes. Psilocybin caused persistent decrease in FC between the anterior hippocampus and default mode network, lasting for weeks. Persistent reduction of hippocampal-default mode network connectivity may represent a neuroanatomical and mechanistic correlate of the proplasticity and therapeutic effects of psychedelics.
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Affiliation(s)
- Joshua S Siegel
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA.
| | - Subha Subramanian
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Demetrius Perry
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Benjamin P Kay
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | - Evan M Gordon
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Timothy O Laumann
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - T Rick Reneau
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Nicholas V Metcalf
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | - Ravi V Chacko
- Department of Emergency Medicine, Advocate Christ Health Care, Oak Lawn, IL, USA
| | - Caterina Gratton
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | | | - Samuel R Krimmel
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | - Joshua S Shimony
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Julie A Schweiger
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Dean F Wong
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - David A Bender
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Kristen M Scheidter
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | - Forrest I Whiting
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | - Jonah A Padawer-Curry
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO, USA
| | - Russell T Shinohara
- Center for Biomedical Image Computing and Analytics, University of Pennsylvania, Philadelphia, PA, USA
- Penn Statistics in Imaging and Visualization Endeavor, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yong Chen
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Julia Moser
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
- Institute of Child Development, University of Minnesota, Minneapolis, MN, USA
| | - Essa Yacoub
- Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA
| | - Steven M Nelson
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Luca Vizioli
- Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA
| | - Damien A Fair
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
- Institute of Child Development, University of Minnesota, Minneapolis, MN, USA
- Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Eric J Lenze
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Robin Carhart-Harris
- Department of Neurology, University of California, San Francisco, CA, USA
- Centre for Psychedelic Research, Imperial College London, London, UK
| | - Charles L Raison
- Usona Institute, Fitchburg, WI, USA
- Department of Psychiatry, University of Wisconsin School of Medicine & Public Health, Madison, WI, USA
| | - Marcus E Raichle
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO, USA
- Department of Psychological and Brain Sciences, Washington University in St Louis, St Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA
| | - Abraham Z Snyder
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Ginger E Nicol
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Nico U F Dosenbach
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO, USA
- Department of Psychological and Brain Sciences, Washington University in St Louis, St Louis, MO, USA
- Department of Pediatrics, Washington University School of Medicine, St Louis, MO, USA
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16
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Savtchenko LP, Rusakov DA. Equal levels of pre- and postsynaptic potentiation produce unequal outcomes. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230235. [PMID: 38853561 PMCID: PMC11343314 DOI: 10.1098/rstb.2023.0235] [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: 10/10/2023] [Revised: 12/06/2023] [Accepted: 01/05/2024] [Indexed: 06/11/2024] Open
Abstract
Which proportion of the long-term potentiation (LTP) expressed in the bulk of excitatory synapses is postsynaptic and which presynaptic remains debatable. To understand better the possible impact of either LTP form, we explored a realistic model of a CA1 pyramidal cell equipped with known membrane mechanisms and multiple, stochastic excitatory axo-spinous synapses. Our simulations were designed to establish an input-output transfer function, the dependence between the frequency of presynaptic action potentials triggering probabilistic synaptic discharges and the average frequency of postsynaptic spiking. We found that, within the typical physiological range, potentiation of the postsynaptic current results in a greater overall output than an equivalent increase in presynaptic release probability. This difference grows stronger at lower input frequencies and lower release probabilities. Simulations with a non-hierarchical circular network of principal neurons indicated that equal increases in either synaptic fidelity or synaptic strength of individual connections also produce distinct changes in network activity, although the network phenomenology is likely to be complex. These observations should help to interpret the machinery of LTP phenomena documented in situ. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Leonid P. Savtchenko
- UCL Queen Square Institute of Neurology, University College London, LondonWC1N 3BG, UK
| | - Dmitri A. Rusakov
- UCL Queen Square Institute of Neurology, University College London, LondonWC1N 3BG, UK
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17
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Bagatelas ED, Kavalali ET. Chronic modulation of cAMP signaling elicits synaptic scaling irrespective of activity. iScience 2024; 27:110176. [PMID: 38989459 PMCID: PMC11233962 DOI: 10.1016/j.isci.2024.110176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/11/2024] [Accepted: 05/31/2024] [Indexed: 07/12/2024] Open
Abstract
Homeostatic plasticity mechanisms act in a negative feedback manner to stabilize neuronal firing around a set point. Classically, homeostatic synaptic plasticity is elicited via rather drastic manipulation of activity in a neuronal population. Here, we employed a chemogenetic approach to regulate activity via eliciting G protein-coupled receptor (GPCR) signaling in hippocampal neurons to trigger homeostatic synaptic plasticity. We demonstrate that chronic activation of hM4D(Gi) signaling induces mild and transient activity suppression, yet still triggers synaptic upscaling akin to tetrodotoxin (TTX)-induced complete activity suppression. Therefore, this homeostatic regulation was irrespective of Gi-signaling regulation of activity, but it was mimicked or occluded by direct manipulation of cyclic AMP (cAMP) signaling in a manner that intersected with the retinoic acid receptor alpha (RARα) signaling pathway. Our data suggest chemogenetic tools can uniquely be used to probe cell-autonomous mechanisms of synaptic scaling and operate via direct modulation of second messenger signaling bypassing activity regulation.
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Affiliation(s)
- Elena D. Bagatelas
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37209, USA
| | - Ege T. Kavalali
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37209, USA
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18
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Koesters AG, Rich MM, Engisch KL. Homeostatic Synaptic Plasticity of Miniature Excitatory Postsynaptic Currents in Mouse Cortical Cultures Requires Neuronal Rab3A. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.14.544980. [PMID: 39071374 PMCID: PMC11275788 DOI: 10.1101/2023.06.14.544980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Following prolonged activity blockade, amplitudes of miniature excitatory postsynaptic currents (mEPSCs) increase, a form of plasticity termed "homeostatic synaptic plasticity." We previously showed that a presynaptic protein, the small GTPase Rab3A, is required for full expression of the increase in miniature endplate current amplitudes following prolonged blockade of action potential activity at the mouse neuromuscular junction in vivo (Wang et al., 2011), but it is unknown whether this form of Rab3A-dependent homeostatic plasticity shares any characteristics with central synapses. We show here that homeostatic synaptic plasticity of mEPSCs is impaired in mouse cortical neuron cultures prepared from Rab3A-/- and mutant mice expressing a single point mutation of Rab3A, Rab3A Earlybird mice. To determine if Rab3A is involved in the well-established homeostatic increase in postsynaptic AMPA-type receptors (AMPARs), we performed a series of experiments in which electrophysiological recordings of mEPSCs and confocal imaging of synaptic AMPAR immunofluorescence were assessed within the same cultures. We found that Rab3A was required for the increase in synaptic AMPARs following prolonged activity blockade, but the increase in mEPSC amplitudes was not always accompanied by an increase in postsynaptic AMPAR levels, suggesting other factors may contribute. Finally, we demonstrate that Rab3A is acting in neurons because only selective loss of Rab3A in neurons, not glia, disrupted the homeostatic increase in mEPSC amplitudes. This is the first demonstration that neuronal Rab3A is required for homeostatic synaptic plasticity and that it does so partially through regulation of the surface expression of AMPA receptors.
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Affiliation(s)
- Andrew G. Koesters
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Mark M. Rich
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45345
| | - Kathrin L. Engisch
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and the College of Science and Mathematics, Wright State University, Dayton, OH 45435
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19
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Caya-Bissonnette L, Béïque JC. Half a century legacy of long-term potentiation. Curr Biol 2024; 34:R640-R662. [PMID: 38981433 DOI: 10.1016/j.cub.2024.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
In 1973, two papers from Bliss and Lømo and from Bliss and Gardner-Medwin reported that high-frequency synaptic stimulation in the dentate gyrus of rabbits resulted in a long-lasting increase in synaptic strength. This form of synaptic plasticity, commonly referred to as long-term potentiation (LTP), was immediately considered as an attractive mechanism accounting for the ability of the brain to store information. In this historical piece looking back over the past 50 years, we discuss how these two landmark contributions directly motivated a colossal research effort and detail some of the resulting milestones that have shaped our evolving understanding of the molecular and cellular underpinnings of LTP. We highlight the main features of LTP, cover key experiments that defined its induction and expression mechanisms, and outline the evidence supporting a potential role of LTP in learning and memory. We also briefly explore some ramifications of LTP on network stability, consider current limitations of LTP as a model of associative memory, and entertain future research orientations.
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Affiliation(s)
- Léa Caya-Bissonnette
- Graduate Program in Neuroscience, University of Ottawa, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada; Brain and Mind Research Institute's Centre for Neural Dynamics and Artificial Intelligence, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada
| | - Jean-Claude Béïque
- Brain and Mind Research Institute's Centre for Neural Dynamics and Artificial Intelligence, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada.
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20
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Song Y, Benna MK. Parallel Synapses with Transmission Nonlinearities Enhance Neuronal Classification Capacity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.01.601490. [PMID: 39005326 PMCID: PMC11244940 DOI: 10.1101/2024.07.01.601490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Cortical neurons often establish multiple synaptic contacts with the same postsynaptic neuron. To avoid functional redundancy of these parallel synapses, it is crucial that each synapse exhibits distinct computational properties. Here we model the current to the soma contributed by each synapse as a sigmoidal transmission function of its presynaptic input, with learnable parameters such as amplitude, slope, and threshold. We evaluate the classification capacity of a neuron equipped with such nonlinear parallel synapses, and show that with a small number of parallel synapses per axon, it substantially exceeds that of the Perceptron. Furthermore, the number of correctly classified data points can increase superlinearly as the number of presynaptic axons grows. When training with an unrestricted number of parallel synapses, our model neuron can effectively implement an arbitrary aggregate transmission function for each axon, constrained only by monotonicity. Nevertheless, successful learning in the model neuron often requires only a small number of parallel synapses. We also apply these parallel synapses in a feedforward neural network trained to classify MNIST images, and show that they can increase the test accuracy. This demonstrates that multiple nonlinear synapses per input axon can substantially enhance a neuron's computational power.
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Affiliation(s)
- Yuru Song
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Marcus K. Benna
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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21
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Van Hook MJ, McCool S. Enhanced Synaptic Inhibition in the Dorsolateral Geniculate Nucleus in a Mouse Model of Glaucoma. eNeuro 2024; 11:ENEURO.0263-24.2024. [PMID: 38937109 PMCID: PMC11242868 DOI: 10.1523/eneuro.0263-24.2024] [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: 06/13/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024] Open
Abstract
Elevated intraocular pressure (IOP) triggers glaucoma by damaging the output neurons of the retina called retinal ganglion cells (RGCs). This leads to the loss of RGC signaling to visual centers of the brain such as the dorsolateral geniculate nucleus (dLGN), which is critical for processing and relaying information to the cortex for conscious vision. In response to altered levels of activity or synaptic input, neurons can homeostatically modulate postsynaptic neurotransmitter receptor numbers, allowing them to scale their synaptic responses to stabilize spike output. While prior work has indicated unaltered glutamate receptor properties in the glaucomatous dLGN, it is unknown whether glaucoma impacts dLGN inhibition. Here, using DBA/2J mice, which develop elevated IOP beginning at 6-7 months of age, we tested whether the strength of inhibitory synapses on dLGN thalamocortical relay neurons is altered in response to the disease state. We found an enhancement of feedforward disynaptic inhibition arising from local interneurons along with increased amplitude of quantal inhibitory synaptic currents. A combination of immunofluorescence staining for the γ-aminobutyric acid (GABA)A-α1 receptor subunit, peak-scaled nonstationary fluctuation analysis, and measures of homeostatic synaptic scaling pointed to an ∼1.4-fold increase in GABA receptors at postsynaptic inhibitory synapses, although several pieces of evidence indicate a nonuniform scaling across inhibitory synapses within individual relay neurons. Together, these results indicate an increase in inhibitory synaptic strength in the glaucomatous dLGN, potentially pointing toward homeostatic compensation for disruptions in network and neuronal function triggered by increased IOP.
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Affiliation(s)
- Matthew J Van Hook
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198
- Departments of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Shaylah McCool
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198
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22
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Gonzalez-Islas C, Sabra Z, Fong MF, Yilmam P, Au Yong N, Engisch K, Wenner P. GABAergic synaptic scaling is triggered by changes in spiking activity rather than AMPA receptor activation. eLife 2024; 12:RP87753. [PMID: 38941139 PMCID: PMC11213567 DOI: 10.7554/elife.87753] [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] [Indexed: 06/29/2024] Open
Abstract
Homeostatic plasticity represents a set of mechanisms that are thought to recover some aspect of neural function. One such mechanism called AMPAergic scaling was thought to be a likely candidate to homeostatically control spiking activity. However, recent findings have forced us to reconsider this idea as several studies suggest AMPAergic scaling is not directly triggered by changes in spiking. Moreover, studies examining homeostatic perturbations in vivo have suggested that GABAergic synapses may be more critical in terms of spiking homeostasis. Here, we show results that GABAergic scaling can act to homeostatically control spiking levels. We found that perturbations which increased or decreased spiking in cortical cultures triggered multiplicative GABAergic upscaling and downscaling, respectively. In contrast, we found that changes in AMPA receptor (AMPAR) or GABAR transmission only influence GABAergic scaling through their indirect effect on spiking. We propose that GABAergic scaling represents a stronger candidate for spike rate homeostat than AMPAergic scaling.
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Affiliation(s)
- Carlos Gonzalez-Islas
- Department of Cell Biology, Emory UniversityAtlantaUnited States
- Doctorado en Ciencias Biológicas Universidad Autónoma de TlaxcalaTlaxMexico
| | - Zahraa Sabra
- Department of Neurosurgery, Emory UniversityAtlantaUnited States
| | - Ming-fai Fong
- Department of Cell Biology, Emory UniversityAtlantaUnited States
- Department of Biomedical Engineering, Georgia Tech and Emory UniversityAtlantaUnited States
| | - Pernille Yilmam
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Nicholas Au Yong
- Department of Neurosurgery, Emory UniversityAtlantaUnited States
| | - Kathrin Engisch
- Department of Neuroscience, Cell Biology and Physiology, Wright State UniversityDaytonUnited States
| | - Peter Wenner
- Department of Cell Biology, Emory UniversityAtlantaUnited States
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23
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Eckmann S, Young EJ, Gjorgjieva J. Synapse-type-specific competitive Hebbian learning forms functional recurrent networks. Proc Natl Acad Sci U S A 2024; 121:e2305326121. [PMID: 38870059 PMCID: PMC11194505 DOI: 10.1073/pnas.2305326121] [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: 04/04/2023] [Accepted: 04/25/2024] [Indexed: 06/15/2024] Open
Abstract
Cortical networks exhibit complex stimulus-response patterns that are based on specific recurrent interactions between neurons. For example, the balance between excitatory and inhibitory currents has been identified as a central component of cortical computations. However, it remains unclear how the required synaptic connectivity can emerge in developing circuits where synapses between excitatory and inhibitory neurons are simultaneously plastic. Using theory and modeling, we propose that a wide range of cortical response properties can arise from a single plasticity paradigm that acts simultaneously at all excitatory and inhibitory connections-Hebbian learning that is stabilized by the synapse-type-specific competition for a limited supply of synaptic resources. In plastic recurrent circuits, this competition enables the formation and decorrelation of inhibition-balanced receptive fields. Networks develop an assembly structure with stronger synaptic connections between similarly tuned excitatory and inhibitory neurons and exhibit response normalization and orientation-specific center-surround suppression, reflecting the stimulus statistics during training. These results demonstrate how neurons can self-organize into functional networks and suggest an essential role for synapse-type-specific competitive learning in the development of cortical circuits.
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Affiliation(s)
- Samuel Eckmann
- Computation in Neural Circuits Group, Max Planck Institute for Brain Research, Frankfurt am Main60438, Germany
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, CambridgeCB2 1PZ, United Kingdom
| | - Edward James Young
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, CambridgeCB2 1PZ, United Kingdom
| | - Julijana Gjorgjieva
- Computation in Neural Circuits Group, Max Planck Institute for Brain Research, Frankfurt am Main60438, Germany
- School of Life Sciences, Technical University Munich, Freising85354, Germany
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24
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Shallow MC, Tian L, Lin H, Lefton KB, Chen S, Dougherty JD, Culver JP, Lambo ME, Hengen KB. At the onset of active whisking, the input layer of barrel cortex exhibits a 24 h window of increased excitability that depends on prior experience. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597353. [PMID: 38895408 PMCID: PMC11185658 DOI: 10.1101/2024.06.04.597353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The development of motor control over sensory organs is a critical milestone in sensory processing, enabling active exploration and shaping of the sensory environment. However, whether the onset of sensory organ motor control directly influences the development of corresponding sensory cortices remains unknown. Here, we exploit the late onset of whisking behavior in mice to address this question in the somatosensory system. Using ex vivo electrophysiology, we discovered a transient increase in the intrinsic excitability of excitatory neurons in layer IV of the barrel cortex, which processes whisker input, precisely coinciding with the onset of active whisking at postnatal day 14 (P14). This increase in neuronal gain was specific to layer IV, independent of changes in synaptic strength, and required prior sensory experience. Strikingly, the effect was not observed in layer II/III of the barrel cortex or in the visual cortex upon eye opening, suggesting a unique interaction between the development of active sensing and the thalamocortical input layer in the somatosensory system. Predictive modeling indicated that changes in active membrane conductances alone could reliably distinguish P14 neurons in control but not whisker-deprived hemispheres. Our findings demonstrate an experience-dependent, lamina-specific refinement of neuronal excitability tightly linked to the emergence of active whisking. This transient increase in the gain of the thalamic input layer coincides with a critical period for synaptic plasticity in downstream layers, suggesting a role in facilitating cortical maturation and sensory processing. Together, our results provide evidence for a direct interaction between the development of motor control and sensory cortex, offering new insights into the experience-dependent development and refinement of sensory systems. These findings have broad implications for understanding the interplay between motor and sensory development, and how the mechanisms of perception cooperate with behavior.
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Affiliation(s)
| | - Lucy Tian
- Department of Biology, Washington University in Saint Louis
| | - Hudson Lin
- Department of Biology, Washington University in Saint Louis
| | - Katheryn B Lefton
- Department of Biology, Washington University in Saint Louis
- Department of Neuroscience, Washington University in Saint Louis
| | - Siyu Chen
- Department of Genetics, Washington University in Saint Louis
| | | | - Joe P Culver
- Department of Radiology, Washington University in Saint Louis
| | - Mary E Lambo
- Department of Biology, Washington University in Saint Louis
| | - Keith B Hengen
- Department of Biology, Washington University in Saint Louis
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25
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Wen W, Turrigiano GG. Modular Arrangement of Synaptic and Intrinsic Homeostatic Plasticity within Visual Cortical Circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596982. [PMID: 38853882 PMCID: PMC11160741 DOI: 10.1101/2024.06.01.596982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Neocortical circuits use synaptic and intrinsic forms of homeostatic plasticity to stabilize key features of network activity, but whether these different homeostatic mechanisms act redundantly, or can be independently recruited to stabilize different network features, is unknown. Here we used pharmacological and genetic perturbations both in vitro and in vivo to determine whether synaptic scaling and intrinsic homeostatic plasticity (IHP) are arranged and recruited in a hierarchical or modular manner within L2/3 pyramidal neurons in rodent V1. Surprisingly, although the expression of synaptic scaling and IHP was dependent on overlapping trafficking pathways, they could be independently recruited by manipulating spiking activity or NMDAR signaling, respectively. Further, we found that changes in visual experience that affect NMDAR activation but not mean firing selectively trigger IHP, without recruiting synaptic scaling. These findings support a modular model in which synaptic and intrinsic homeostatic plasticity respond to and stabilize distinct aspects of network activity.
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Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
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26
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Wise DL, Escobedo-Lozoya Y, Valakh V, Gao EY, Bhonsle A, Lei QL, Cheng X, Greene SB, Van Hooser SD, Nelson SB. Prolonged Activity Deprivation Causes Pre- and Postsynaptic Compensatory Plasticity at Neocortical Excitatory Synapses. eNeuro 2024; 11:ENEURO.0366-23.2024. [PMID: 38777611 PMCID: PMC11163391 DOI: 10.1523/eneuro.0366-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 05/10/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
Homeostatic plasticity stabilizes firing rates of neurons, but the pressure to restore low activity rates can significantly alter synaptic and cellular properties. Most previous studies of homeostatic readjustment to complete activity silencing in rodent forebrain have examined changes after 2 d of deprivation, but it is known that longer periods of deprivation can produce adverse effects. To better understand the mechanisms underlying these effects and to address how presynaptic as well as postsynaptic compartments change during homeostatic plasticity, we subjected mouse cortical slice cultures to a more severe 5 d deprivation paradigm. We developed and validated a computational framework to measure the number and morphology of presynaptic and postsynaptic compartments from super-resolution light microscopy images of dense cortical tissue. Using these tools, combined with electrophysiological miniature excitatory postsynaptic current measurements, and synaptic imaging at the electron microscopy level, we assessed the functional and morphological results of prolonged deprivation. Excitatory synapses were strengthened both presynaptically and postsynaptically. Surprisingly, we also observed a decrement in the density of excitatory synapses, both as measured from colocalized staining of pre- and postsynaptic proteins in tissue and from the number of dendritic spines. Overall, our results suggest that cortical networks deprived of activity progressively move toward a smaller population of stronger synapses.
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Affiliation(s)
- Derek L Wise
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | | | - Vera Valakh
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | - Emma Y Gao
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | - Aishwarya Bhonsle
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | - Qian L Lei
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | - Xinyu Cheng
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | - Samuel B Greene
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
| | | | - Sacha B Nelson
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454 9110
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27
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Koster KP, Fyke Z, Nguyen TTA, Niqula A, Noriega-González LY, Woolfrey KM, Dell’Acqua ML, Cologna SM, Yoshii A. Akap5 links synaptic dysfunction to neuroinflammatory signaling in a mouse model of infantile neuronal ceroid lipofuscinosis. Front Synaptic Neurosci 2024; 16:1384625. [PMID: 38798824 PMCID: PMC11116793 DOI: 10.3389/fnsyn.2024.1384625] [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: 02/10/2024] [Accepted: 04/23/2024] [Indexed: 05/29/2024] Open
Abstract
Palmitoylation and depalmitoylation represent dichotomic processes by which a labile posttranslational lipid modification regulates protein trafficking and degradation. The depalmitoylating enzyme, palmitoyl-protein thioesterase 1 (PPT1), is associated with the devastating pediatric neurodegenerative condition, infantile neuronal ceroid lipofuscinosis (CLN1). CLN1 is characterized by the accumulation of autofluorescent lysosomal storage material (AFSM) in neurons and robust neuroinflammation. Converging lines of evidence suggest that in addition to cellular waste accumulation, the symptomology of CLN1 corresponds with disruption of synaptic processes. Indeed, loss of Ppt1 function in cortical neurons dysregulates the synaptic incorporation of the GluA1 AMPA receptor (AMPAR) subunit during a type of synaptic plasticity called synaptic scaling. However, the mechanisms causing this aberration are unknown. Here, we used the Ppt1-/- mouse model (both sexes) to further investigate how Ppt1 regulates synaptic plasticity and how its disruption affects downstream signaling pathways. To this end, we performed a palmitoyl-proteomic screen, which provoked the discovery that Akap5 is excessively palmitoylated at Ppt1-/- synapses. Extending our previous data, in vivo induction of synaptic scaling, which is regulated by Akap5, caused an excessive upregulation of GluA1 in Ppt1-/- mice. This synaptic change was associated with exacerbated disease pathology. Furthermore, the Akap5- and inflammation-associated transcriptional regulator, nuclear factor of activated T cells (NFAT), was sensitized in Ppt1-/- cortical neurons. Suppressing the upstream regulator of NFAT activation, calcineurin, with the FDA-approved therapeutic FK506 (Tacrolimus) modestly improved neuroinflammation in Ppt1-/- mice. These findings indicate that the absence of depalmitoylation stifles synaptic protein trafficking and contributes to neuroinflammation via an Akap5-associated mechanism.
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Affiliation(s)
- Kevin P. Koster
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Zach Fyke
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Thu T. A. Nguyen
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, United States
| | - Amanda Niqula
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
| | | | - Kevin M. Woolfrey
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Stephanie M. Cologna
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, United States
| | - Akira Yoshii
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL, United States
- Department of Neurology, University of Illinois at Chicago, Chicago, IL, United States
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28
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Zeldenrust F, Calcini N, Yan X, Bijlsma A, Celikel T. The tuning of tuning: How adaptation influences single cell information transfer. PLoS Comput Biol 2024; 20:e1012043. [PMID: 38739640 PMCID: PMC11115315 DOI: 10.1371/journal.pcbi.1012043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 05/23/2024] [Accepted: 04/01/2024] [Indexed: 05/16/2024] Open
Abstract
Sensory neurons reconstruct the world from action potentials (spikes) impinging on them. To effectively transfer information about the stimulus to the next processing level, a neuron needs to be able to adapt its working range to the properties of the stimulus. Here, we focus on the intrinsic neural properties that influence information transfer in cortical neurons and how tightly their properties need to be tuned to the stimulus statistics for them to be effective. We start by measuring the intrinsic information encoding properties of putative excitatory and inhibitory neurons in L2/3 of the mouse barrel cortex. Excitatory neurons show high thresholds and strong adaptation, making them fire sparsely and resulting in a strong compression of information, whereas inhibitory neurons that favour fast spiking transfer more information. Next, we turn to computational modelling and ask how two properties influence information transfer: 1) spike-frequency adaptation and 2) the shape of the IV-curve. We find that a subthreshold (but not threshold) adaptation, the 'h-current', and a properly tuned leak conductance can increase the information transfer of a neuron, whereas threshold adaptation can increase its working range. Finally, we verify the effect of the IV-curve slope in our experimental recordings and show that excitatory neurons form a more heterogeneous population than inhibitory neurons. These relationships between intrinsic neural features and neural coding that had not been quantified before will aid computational, theoretical and systems neuroscientists in understanding how neuronal populations can alter their coding properties, such as through the impact of neuromodulators. Why the variability of intrinsic properties of excitatory neurons is larger than that of inhibitory ones is an exciting question, for which future research is needed.
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Affiliation(s)
- Fleur Zeldenrust
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen - the Netherlands
| | - Niccolò Calcini
- Maastricht Centre for Systems Biology (MaCSBio), University of Maastricht, Maastricht, The Netherlands
| | - Xuan Yan
- Institute of Neuroscience, Chinese Academy of Sciences, Beijing, China
| | - Ate Bijlsma
- Department of Population Health Sciences / Department of Biology, Universiteit Utrecht, the Netherlands
| | - Tansu Celikel
- School of Psychology, Georgia Institute of Technology, Atlanta - GA, United States of America
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29
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Wise DL, Greene SB, Escobedo-Lozoya Y, Van Hooser SD, Nelson SB. Progressive Circuit Hyperexcitability in Mouse Neocortical Slice Cultures with Increasing Duration of Activity Silencing. eNeuro 2024; 11:ENEURO.0362-23.2024. [PMID: 38653560 PMCID: PMC11079856 DOI: 10.1523/eneuro.0362-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
Forebrain neurons deprived of activity become hyperactive when activity is restored. Rebound activity has been linked to spontaneous seizures in vivo following prolonged activity blockade. Here, we measured the time course of rebound activity and the contributing circuit mechanisms using calcium imaging, synaptic staining, and whole-cell patch clamp in organotypic slice cultures of mouse neocortex. Calcium imaging revealed hypersynchronous activity increasing in intensity with longer periods of deprivation. While activity partially recovered 3 d after slices were released from 5 d of deprivation, they were less able to recover after 10 d of deprivation. However, even after the longer period of deprivation, activity patterns eventually returned to baseline levels. The degree of deprivation-induced rebound was age-dependent, with the greatest effects occurring when silencing began in the second week. Pharmacological blockade of NMDA receptors indicated that hypersynchronous rebound activity did not require activation of Hebbian plasticity. In single-neuron recordings, input resistance roughly doubled with a concomitant increase in intrinsic excitability. Synaptic imaging of pre- and postsynaptic proteins revealed dramatic reductions in the number of presumptive synapses with a larger effect on inhibitory than excitatory synapses. Putative excitatory synapses colocalizing PSD-95 and Bassoon declined by 39 and 56% following 5 and 10 d of deprivation, but presumptive inhibitory synapses colocalizing gephyrin and VGAT declined by 55 and 73%, respectively. The results suggest that with prolonged deprivation, a progressive reduction in synapse number is accompanied by a shift in the balance between excitation and inhibition and increased cellular excitability.
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Affiliation(s)
- Derek L Wise
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Samuel B Greene
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | | | | | - Sacha B Nelson
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
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30
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Sun SED, Levenstein D, Li B, Mandelberg N, Chenouard N, Suutari BS, Sanchez S, Tian G, Rinzel J, Buzsáki G, Tsien RW. Synaptic homeostasis transiently leverages Hebbian mechanisms for a multiphasic response to inactivity. Cell Rep 2024; 43:113839. [PMID: 38507409 DOI: 10.1016/j.celrep.2024.113839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/19/2023] [Accepted: 02/05/2024] [Indexed: 03/22/2024] Open
Abstract
Homeostatic regulation of synapses is vital for nervous system function and key to understanding a range of neurological conditions. Synaptic homeostasis is proposed to operate over hours to counteract the destabilizing influence of long-term potentiation (LTP) and long-term depression (LTD). The prevailing view holds that synaptic scaling is a slow first-order process that regulates postsynaptic glutamate receptors and fundamentally differs from LTP or LTD. Surprisingly, we find that the dynamics of scaling induced by neuronal inactivity are not exponential or monotonic, and the mechanism requires calcineurin and CaMKII, molecules dominant in LTD and LTP. Our quantitative model of these enzymes reconstructs the unexpected dynamics of homeostatic scaling and reveals how synapses can efficiently safeguard future capacity for synaptic plasticity. This mechanism of synaptic adaptation supports a broader set of homeostatic changes, including action potential autoregulation, and invites further inquiry into how such a mechanism varies in health and disease.
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Affiliation(s)
- Simón E D Sun
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Daniel Levenstein
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, 3810 University Street, Montreal, QC, Canada
| | - Boxing Li
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China
| | - Nataniel Mandelberg
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Nicolas Chenouard
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Sorbonne Université, INSERM U1127, UMR CNRS 7225, Institut du Cerveau (ICM), 47 bld de l'hôpital, 75013 Paris, France
| | - Benjamin S Suutari
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Sandrine Sanchez
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Guoling Tian
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - John Rinzel
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - György Buzsáki
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Richard W Tsien
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
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31
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Wang CS, McCarthy CI, Guzikowski NJ, Kavalali ET, Monteggia LM. Brain-derived neurotrophic factor scales presynaptic calcium transients to modulate excitatory neurotransmission. Proc Natl Acad Sci U S A 2024; 121:e2303664121. [PMID: 38621124 PMCID: PMC11047077 DOI: 10.1073/pnas.2303664121] [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: 03/06/2023] [Accepted: 02/28/2024] [Indexed: 04/17/2024] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays a critical role in synaptic physiology, as well as mechanisms underlying various neuropsychiatric diseases and their treatment. Despite its clear physiological role and disease relevance, BDNF's function at the presynaptic terminal, a fundamental unit of neurotransmission, remains poorly understood. In this study, we evaluated single synapse dynamics using optical imaging techniques in hippocampal cell cultures. We find that exogenous BDNF selectively increases evoked excitatory neurotransmission without affecting spontaneous neurotransmission. However, acutely blocking endogenous BDNF has no effect on evoked or spontaneous release, demonstrating that different approaches to studying BDNF may yield different results. When we suppressed BDNF-Tropomyosin receptor kinase B (TrkB) activity chronically over a period of days to weeks using a mouse line enabling conditional knockout of TrkB, we found that evoked glutamate release was significantly decreased while spontaneous release remained unchanged. Moreover, chronic blockade of BDNF-TrkB activity selectively downscales evoked calcium transients without affecting spontaneous calcium events. Via pharmacological blockade by voltage-gated calcium channel (VGCC) selective blockers, we found that the changes in evoked calcium transients are mediated by the P/Q subtype of VGCCs. These results suggest that BDNF-TrkB activity increases presynaptic VGCC activity to selectively increase evoked glutamate release.
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Affiliation(s)
- Camille S. Wang
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN3729-7933
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240-7933
| | - Clara I. McCarthy
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN3729-7933
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240-7933
| | - Natalie J. Guzikowski
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN3729-7933
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240-7933
| | - Ege T. Kavalali
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN3729-7933
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240-7933
| | - Lisa M. Monteggia
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN3729-7933
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240-7933
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32
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Zárate-Rochín AM. Contemporary neurocognitive models of memory: A descriptive comparative analysis. Neuropsychologia 2024; 196:108846. [PMID: 38430963 DOI: 10.1016/j.neuropsychologia.2024.108846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/05/2024]
Abstract
The great complexity involved in the study of memory has given rise to numerous hypotheses and models associated with various phenomena at different levels of analysis. This has allowed us to delve deeper in our knowledge about memory but has also made it difficult to synthesize and integrate data from different lines of research. In this context, this work presents a descriptive comparative analysis of contemporary models that address the structure and function of multiple memory systems. The main goal is to outline a panoramic view of the key elements that constitute these models in order to visualize both the current state of research and possible future directions. The elements that stand out from different levels of analysis are distributed neural networks, hierarchical organization, predictive coding, homeostasis, and evolutionary perspective.
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Affiliation(s)
- Alba Marcela Zárate-Rochín
- Instituto de Investigaciones Cerebrales, Universidad Veracruzana, Dr. Castelazo Ayala s/n, Industrial Animas, 91190, Xalapa-Enríquez, Veracruz, Mexico.
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33
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Godavarthi SK, Hiramoto M, Ignatyev Y, Levin JB, Li HQ, Pratelli M, Borchardt J, Czajkowski C, Borodinsky LN, Sweeney L, Cline HT, Spitzer NC. Postsynaptic receptors regulate presynaptic transmitter stability through transsynaptic bridges. Proc Natl Acad Sci U S A 2024; 121:e2318041121. [PMID: 38568976 PMCID: PMC11009644 DOI: 10.1073/pnas.2318041121] [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: 10/17/2023] [Accepted: 02/27/2024] [Indexed: 04/05/2024] Open
Abstract
Stable matching of neurotransmitters with their receptors is fundamental to synapse function and reliable communication in neural circuits. Presynaptic neurotransmitters regulate the stabilization of postsynaptic transmitter receptors. Whether postsynaptic receptors regulate stabilization of presynaptic transmitters has received less attention. Here, we show that blockade of endogenous postsynaptic acetylcholine receptors (AChR) at the neuromuscular junction destabilizes the cholinergic phenotype in motor neurons and stabilizes an earlier, developmentally transient glutamatergic phenotype. Further, expression of exogenous postsynaptic gamma-aminobutyric acid type A receptors (GABAA receptors) in muscle cells stabilizes an earlier, developmentally transient GABAergic motor neuron phenotype. Both AChR and GABAA receptors are linked to presynaptic neurons through transsynaptic bridges. Knockdown of specific components of these transsynaptic bridges prevents stabilization of the cholinergic or GABAergic phenotypes. Bidirectional communication can enforce a match between transmitter and receptor and ensure the fidelity of synaptic transmission. Our findings suggest a potential role of dysfunctional transmitter receptors in neurological disorders that involve the loss of the presynaptic transmitter.
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Affiliation(s)
- Swetha K. Godavarthi
- Neurobiology Department, University of California San Diego, La Jolla, CA92093
- Kavli Institute for Brain & Mind, University of California San Diego, La Jolla, CA92093
| | - Masaki Hiramoto
- Neuroscience Department, The Scripps Research Institute, La Jolla, CA92037
| | - Yuri Ignatyev
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Jacqueline B. Levin
- Department of Physiology & Membrane Biology Shriners Hospital for Children Northern California, University of California Davis School of Medicine, Sacramento, CA95817
| | - Hui-quan Li
- Neurobiology Department, University of California San Diego, La Jolla, CA92093
- Kavli Institute for Brain & Mind, University of California San Diego, La Jolla, CA92093
| | - Marta Pratelli
- Neurobiology Department, University of California San Diego, La Jolla, CA92093
- Kavli Institute for Brain & Mind, University of California San Diego, La Jolla, CA92093
| | - Jennifer Borchardt
- Neuroscience Department, University of Wisconsin Madison, Madison, WI53705
| | - Cynthia Czajkowski
- Neuroscience Department, University of Wisconsin Madison, Madison, WI53705
| | - Laura N. Borodinsky
- Department of Physiology & Membrane Biology Shriners Hospital for Children Northern California, University of California Davis School of Medicine, Sacramento, CA95817
| | - Lora Sweeney
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Hollis T. Cline
- Neuroscience Department, The Scripps Research Institute, La Jolla, CA92037
| | - Nicholas C. Spitzer
- Neurobiology Department, University of California San Diego, La Jolla, CA92093
- Kavli Institute for Brain & Mind, University of California San Diego, La Jolla, CA92093
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34
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Van Hook MJ, McCool S. Nonuniform scaling of synaptic inhibition in the dorsolateral geniculate nucleus in a mouse model of glaucoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.587036. [PMID: 38586044 PMCID: PMC10996666 DOI: 10.1101/2024.03.27.587036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Elevated intraocular pressure (IOP) triggers glaucoma by damaging the output neurons of the retina called retinal ganglion cells (RGCs). This leads to the loss of RGC signaling to visual centers of the brain such as the dorsolateral geniculate nucleus (dLGN), which is critical for processing and relaying information to the cortex for conscious vision. In response to altered levels of activity or synaptic input, neurons can homeostatically modulate postsynaptic neurotransmitter receptor numbers, allowing them to scale their synaptic responses to stabilize spike output. While prior work has indicated unaltered glutamate receptor properties in the glaucomatous dLGN, it is unknown whether glaucoma impacts dLGN inhibition. Here, using DBA/2J mice, which develop elevated IOP beginning at 6-7 months of age, we tested whether the strength of inhibitory synapses on dLGN thalamocortical relay neurons is altered in response to the disease state. We found an enhancement of feed-forward disynaptic inhibition arising from local interneurons along with increased amplitude of quantal inhibitory synaptic currents. A combination of immunofluorescence staining for the GABA A -α1 receptor subunit, peak-scaled nonstationary fluctuation analysis, and measures of homeostatic synaptic scaling indicated this was the result of an approximately 1.4-fold increase in GABA receptor number at post-synaptic inhibitory synapses, although several pieces of evidence strongly indicate a non-uniform scaling across inhibitory synapses within individual relay neurons. Together, these results indicate an increase in inhibitory synaptic strength in the glaucomatous dLGN, potentially pointing toward homeostatic compensation for disruptions in network and neuronal function triggered by increased IOP. Significance Statement Elevated eye pressure in glaucoma leads to loss of retinal outputs to the dorsolateral geniculate nucleus (dLGN), which is critical for relaying information to the cortex for conscious vision. Alterations in neuronal activity, as could arise from excitatory synapse loss, can trigger homeostatic adaptations to synaptic function that attempt to maintain activity within a meaningful dynamic range, although whether this occurs uniformly at all synapses within a given neuron or is a non-uniform process is debated. Here, using a mouse model of glaucoma, we show that dLGN inhibitory synapses undergo non-uniform upregulation due to addition of post-synaptic GABA receptors. This is likely to be a neuronal adaptation to glaucomatous pathology in an important sub-cortical visual center.
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35
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Tamosiunaite M, Tetzlaff C, Wörgötter F. Unsupervised learning of perceptual feature combinations. PLoS Comput Biol 2024; 20:e1011926. [PMID: 38442095 PMCID: PMC10942261 DOI: 10.1371/journal.pcbi.1011926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 03/15/2024] [Accepted: 02/19/2024] [Indexed: 03/07/2024] Open
Abstract
In many situations it is behaviorally relevant for an animal to respond to co-occurrences of perceptual, possibly polymodal features, while these features alone may have no importance. Thus, it is crucial for animals to learn such feature combinations in spite of the fact that they may occur with variable intensity and occurrence frequency. Here, we present a novel unsupervised learning mechanism that is largely independent of these contingencies and allows neurons in a network to achieve specificity for different feature combinations. This is achieved by a novel correlation-based (Hebbian) learning rule, which allows for linear weight growth and which is combined with a mechanism for gradually reducing the learning rate as soon as the neuron's response becomes feature combination specific. In a set of control experiments, we show that other existing advanced learning rules cannot satisfactorily form ordered multi-feature representations. In addition, we show that networks, which use this type of learning always stabilize and converge to subsets of neurons with different feature-combination specificity. Neurons with this property may, thus, serve as an initial stage for the processing of ecologically relevant real world situations for an animal.
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Affiliation(s)
- Minija Tamosiunaite
- Department for Computational Neuroscience, Third Physics Institute, University of Göttingen, Göttingen, Germany
- Vytautas Magnus University, Faculty of Informatics, Kaunas, Lithuania
| | - Christian Tetzlaff
- Computational Synaptic Physiology, Department for Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
- Campus Institute Data Science, Göttingen, Germany
| | - Florentin Wörgötter
- Department for Computational Neuroscience, Third Physics Institute, University of Göttingen, Göttingen, Germany
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36
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Sharma V, Swaminathan K, Shukla R. The Ribosome Hypothesis: Decoding Mood Disorder Complexity. Int J Mol Sci 2024; 25:2815. [PMID: 38474062 PMCID: PMC10931790 DOI: 10.3390/ijms25052815] [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: 01/19/2024] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
Several types of mood disorders lie along a continuum, with nebulous boundaries between them. Understanding the mechanisms that contribute to mood disorder complexity is critical for effective treatment. However, present treatments are largely centered around neurotransmission and receptor-based hypotheses, which, given the high instance of treatment resistance, fail to adequately explain the complexities of mood disorders. In this opinion piece, based on our recent results, we propose a ribosome hypothesis of mood disorders. We suggest that any hypothesis seeking to explain the diverse nature of mood disorders must incorporate infrastructure diversity that results in a wide range of effects. Ribosomes, with their mobility across neurites and complex composition, have the potential to become specialized during stress; thus, ribosome diversity and dysregulation are well suited to explaining mood disorder complexity. Here, we first establish a framework connecting ribosomes to the current state of knowledge associated with mood disorders. Then, we describe the potential mechanisms through which ribosomes could homeostatically regulate systems to manifest diverse mood disorder phenotypes and discuss approaches for substantiating the ribosome hypothesis. Investigating these mechanisms as therapeutic targets holds promise for transdiagnostic avenues targeting mood disorders.
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Affiliation(s)
- Vandana Sharma
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA;
- Department of Neurosciences, University of Wyoming, Laramie, WY 82071, USA
| | - Karthik Swaminathan
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA;
- Department of Neurosciences, University of Wyoming, Laramie, WY 82071, USA
| | - Rammohan Shukla
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA;
- Department of Neurosciences, University of Wyoming, Laramie, WY 82071, USA
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37
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Lemieux M, Karimi N, Bretzner F. Functional plasticity of glutamatergic neurons of medullary reticular nuclei after spinal cord injury in mice. Nat Commun 2024; 15:1542. [PMID: 38378819 PMCID: PMC10879492 DOI: 10.1038/s41467-024-45300-4] [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: 07/26/2023] [Accepted: 01/17/2024] [Indexed: 02/22/2024] Open
Abstract
Spinal cord injury disrupts the descending command from the brain and causes a range of motor deficits. Here, we use optogenetic tools to investigate the functional plasticity of the glutamatergic reticulospinal drive of the medullary reticular formation after a lateral thoracic hemisection in female mice. Sites evoking stronger excitatory descending drive in intact conditions are the most impaired after injury, whereas those associated with a weaker drive are potentiated. After lesion, pro- and anti-locomotor activities (that is, initiation/acceleration versus stop/deceleration) are overall preserved. Activating the descending reticulospinal drive improves stepping ability on a flat surface of chronically impaired injured mice, and its priming enhances recovery of skilled locomotion on a horizontal ladder. This study highlights the resilience and capacity for reorganization of the glutamatergic reticulospinal command after injury, along with its suitability as a therapeutical target to promote functional recovery.
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Affiliation(s)
- Maxime Lemieux
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC, G1V 4G2, Canada
| | - Narges Karimi
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC, G1V 4G2, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, G1V 4G2, Canada
| | - Frederic Bretzner
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC, G1V 4G2, Canada.
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, G1V 4G2, Canada.
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38
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Koesters AG, Rich MM, Engisch KL. Diverging from the Norm: Reevaluating What Miniature Excitatory Postsynaptic Currents Tell Us about Homeostatic Synaptic Plasticity. Neuroscientist 2024; 30:49-70. [PMID: 35904350 DOI: 10.1177/10738584221112336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The idea that the nervous system maintains a set point of network activity and homeostatically returns to that set point in the face of dramatic disruption-during development, after injury, in pathologic states, and during sleep/wake cycles-is rapidly becoming accepted as a key plasticity behavior, placing it alongside long-term potentiation and depression. The dramatic growth in studies of homeostatic synaptic plasticity of miniature excitatory synaptic currents (mEPSCs) is attributable, in part, to the simple yet elegant mechanism of uniform multiplicative scaling proposed by Turrigiano and colleagues: that neurons sense their own activity and globally multiply the strength of every synapse by a single factor to return activity to the set point without altering established differences in synaptic weights. We have recently shown that for mEPSCs recorded from control and activity-blocked cultures of mouse cortical neurons, the synaptic scaling factor is not uniform but is close to 1 for the smallest mEPSC amplitudes and progressively increases as mEPSC amplitudes increase, which we term divergent scaling. Using insights gained from simulating uniform multiplicative scaling, we review evidence from published studies and conclude that divergent synaptic scaling is the norm rather than the exception. This conclusion has implications for hypotheses about the molecular mechanisms underlying synaptic scaling.
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Affiliation(s)
- Andrew G Koesters
- Department of Behavior, Cognition, and Neurophysiology, Environmental Health Effects Laboratory, Naval Medical Research Unit-Dayton, Wright-Patterson AFB, OH, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology, and Physiology, College of Science and Mathematics, and Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Kathrin L Engisch
- Department of Neuroscience, Cell Biology, and Physiology, College of Science and Mathematics, and Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
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39
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Shirani F, Choi H. On the physiological and structural contributors to the overall balance of excitation and inhibition in local cortical networks. J Comput Neurosci 2024; 52:73-107. [PMID: 37837534 DOI: 10.1007/s10827-023-00863-x] [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: 04/13/2023] [Revised: 06/25/2023] [Accepted: 09/08/2023] [Indexed: 10/16/2023]
Abstract
Overall balance of excitation and inhibition in cortical networks is central to their functionality and normal operation. Such orchestrated co-evolution of excitation and inhibition is established through convoluted local interactions between neurons, which are organized by specific network connectivity structures and are dynamically controlled by modulating synaptic activities. Therefore, identifying how such structural and physiological factors contribute to establishment of overall balance of excitation and inhibition is crucial in understanding the homeostatic plasticity mechanisms that regulate the balance. We use biologically plausible mathematical models to extensively study the effects of multiple key factors on overall balance of a network. We characterize a network's baseline balanced state by certain functional properties, and demonstrate how variations in physiological and structural parameters of the network deviate this balance and, in particular, result in transitions in spontaneous activity of the network to high-amplitude slow oscillatory regimes. We show that deviations from the reference balanced state can be continuously quantified by measuring the ratio of mean excitatory to mean inhibitory synaptic conductances in the network. Our results suggest that the commonly observed ratio of the number of inhibitory to the number of excitatory neurons in local cortical networks is almost optimal for their stability and excitability. Moreover, the values of inhibitory synaptic decay time constants and density of inhibitory-to-inhibitory network connectivity are critical to overall balance and stability of cortical networks. However, network stability in our results is sufficiently robust against modulations of synaptic quantal conductances, as required by their role in learning and memory. Our study based on extensive bifurcation analyses thus reveal the functional optimality and criticality of structural and physiological parameters in establishing the baseline operating state of local cortical networks.
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Affiliation(s)
- Farshad Shirani
- School of Mathematics, Georgia Institute of Technology, Atlanta, 30332, Georgia, USA.
| | - Hannah Choi
- School of Mathematics, Georgia Institute of Technology, Atlanta, 30332, Georgia, USA
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40
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McClaskey CM. Neural hyperactivity and altered envelope encoding in the central auditory system: Changes with advanced age and hearing loss. Hear Res 2024; 442:108945. [PMID: 38154191 PMCID: PMC10942735 DOI: 10.1016/j.heares.2023.108945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 12/04/2023] [Accepted: 12/22/2023] [Indexed: 12/30/2023]
Abstract
Temporal modulations are ubiquitous features of sound signals that are important for auditory perception. The perception of temporal modulations, or temporal processing, is known to decline with aging and hearing loss and negatively impact auditory perception in general and speech recognition specifically. However, neurophysiological literature also provides evidence of exaggerated or enhanced encoding of specifically temporal envelopes in aging and hearing loss, which may arise from changes in inhibitory neurotransmission and neuronal hyperactivity. This review paper describes the physiological changes to the neural encoding of temporal envelopes that have been shown to occur with age and hearing loss and discusses the role of disinhibition and neural hyperactivity in contributing to these changes. Studies in both humans and animal models suggest that aging and hearing loss are associated with stronger neural representations of both periodic amplitude modulation envelopes and of naturalistic speech envelopes, but primarily for low-frequency modulations (<80 Hz). Although the frequency dependence of these results is generally taken as evidence of amplified envelope encoding at the cortex and impoverished encoding at the midbrain and brainstem, there is additional evidence to suggest that exaggerated envelope encoding may also occur subcortically, though only for envelopes with low modulation rates. A better understanding of how temporal envelope encoding is altered in aging and hearing loss, and the contexts in which neural responses are exaggerated/diminished, may aid in the development of interventions, assistive devices, and treatment strategies that work to ameliorate age- and hearing-loss-related auditory perceptual deficits.
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Affiliation(s)
- Carolyn M McClaskey
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Ave, MSC 550, Charleston, SC 29425, United States.
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41
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Diehl GW, Redish AD. Measuring excitation-inhibition balance through spectral components of local field potentials. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.24.577086. [PMID: 38328057 PMCID: PMC10849740 DOI: 10.1101/2024.01.24.577086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The balance between excitation and inhibition is critical to brain functioning, and dysregulation of this balance is a hallmark of numerous psychiatric conditions. Measuring this excitation-inhibition (E:I) balance in vivo has remained difficult, but theoretical models have proposed that characteristics of local field potentials (LFP) may provide an accurate proxy. To establish a conclusive link between LFP and E:I balance, we recorded single units and LFP from the prefrontal cortex (mPFC) of rats during decision making. Dynamic measures of synaptic coupling strength facilitated direct quantification of E:I balance and revealed a strong inverse relationship to broadband spectral power of LFP. These results provide a critical link between LFP and underlying network properties, opening the door for non-invasive recordings to measure E:I balance in clinical settings.
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Affiliation(s)
- Geoffrey W Diehl
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - A David Redish
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
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42
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Ruffini G, Lopez-Sola E, Vohryzek J, Sanchez-Todo R. Neural Geometrodynamics, Complexity, and Plasticity: A Psychedelics Perspective. ENTROPY (BASEL, SWITZERLAND) 2024; 26:90. [PMID: 38275498 PMCID: PMC11154528 DOI: 10.3390/e26010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024]
Abstract
We explore the intersection of neural dynamics and the effects of psychedelics in light of distinct timescales in a framework integrating concepts from dynamics, complexity, and plasticity. We call this framework neural geometrodynamics for its parallels with general relativity's description of the interplay of spacetime and matter. The geometry of trajectories within the dynamical landscape of "fast time" dynamics are shaped by the structure of a differential equation and its connectivity parameters, which themselves evolve over "slow time" driven by state-dependent and state-independent plasticity mechanisms. Finally, the adjustment of plasticity processes (metaplasticity) takes place in an "ultraslow" time scale. Psychedelics flatten the neural landscape, leading to heightened entropy and complexity of neural dynamics, as observed in neuroimaging and modeling studies linking increases in complexity with a disruption of functional integration. We highlight the relationship between criticality, the complexity of fast neural dynamics, and synaptic plasticity. Pathological, rigid, or "canalized" neural dynamics result in an ultrastable confined repertoire, allowing slower plastic changes to consolidate them further. However, under the influence of psychedelics, the destabilizing emergence of complex dynamics leads to a more fluid and adaptable neural state in a process that is amplified by the plasticity-enhancing effects of psychedelics. This shift manifests as an acute systemic increase of disorder and a possibly longer-lasting increase in complexity affecting both short-term dynamics and long-term plastic processes. Our framework offers a holistic perspective on the acute effects of these substances and their potential long-term impacts on neural structure and function.
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Affiliation(s)
- Giulio Ruffini
- Brain Modeling Department, Neuroelectrics, 08035 Barcelona, Spain; (E.L.-S.); (R.S.-T.)
| | - Edmundo Lopez-Sola
- Brain Modeling Department, Neuroelectrics, 08035 Barcelona, Spain; (E.L.-S.); (R.S.-T.)
- Computational Neuroscience Group, Universitat Pompeu Fabra, 08018 Barcelona, Spain;
| | - Jakub Vohryzek
- Computational Neuroscience Group, Universitat Pompeu Fabra, 08018 Barcelona, Spain;
- Centre for Eudaimonia and Human Flourishing, Linacre College, University of Oxford, Oxford OX3 9BX, UK
| | - Roser Sanchez-Todo
- Brain Modeling Department, Neuroelectrics, 08035 Barcelona, Spain; (E.L.-S.); (R.S.-T.)
- Computational Neuroscience Group, Universitat Pompeu Fabra, 08018 Barcelona, Spain;
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43
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Kruse P, Brandes G, Hemeling H, Huang Z, Wrede C, Hegermann J, Vlachos A, Lenz M. Synaptopodin Regulates Denervation-Induced Plasticity at Hippocampal Mossy Fiber Synapses. Cells 2024; 13:114. [PMID: 38247806 PMCID: PMC10814840 DOI: 10.3390/cells13020114] [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: 11/21/2023] [Revised: 12/17/2023] [Accepted: 12/27/2023] [Indexed: 01/23/2024] Open
Abstract
Neurological diseases can lead to the denervation of brain regions caused by demyelination, traumatic injury or cell death. The molecular and structural mechanisms underlying lesion-induced reorganization of denervated brain regions, however, are a matter of ongoing investigation. In order to address this issue, we performed an entorhinal cortex lesion (ECL) in mouse organotypic entorhino-hippocampal tissue cultures of both sexes and studied denervation-induced plasticity of mossy fiber synapses, which connect dentate granule cells (dGCs) with CA3 pyramidal cells (CA3-PCs) and play important roles in learning and memory formation. Partial denervation caused a strengthening of excitatory neurotransmission in dGCs, CA3-PCs and their direct synaptic connections, as revealed by paired recordings (dGC-to-CA3-PC). These functional changes were accompanied by ultrastructural reorganization of mossy fiber synapses, which regularly contain the plasticity-regulating protein synaptopodin and the spine apparatus organelle. We demonstrate that the spine apparatus organelle and synaptopodin are related to ribosomes in close proximity to synaptic sites and reveal a synaptopodin-related transcriptome. Notably, synaptopodin-deficient tissue preparations that lack the spine apparatus organelle failed to express lesion-induced synaptic adjustments. Hence, synaptopodin and the spine apparatus organelle play a crucial role in regulating lesion-induced synaptic plasticity at hippocampal mossy fiber synapses.
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Affiliation(s)
- Pia Kruse
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Gudrun Brandes
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany
| | - Hanna Hemeling
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Zhong Huang
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, 30625 Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, 30625 Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, 30625 Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, 30625 Hannover, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- Center BrainLinks-BrainTools, University of Freiburg, 79104 Freiburg, Germany
| | - Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany
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44
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Fetterly TL, Catalfio AM, Ferrario CR. Effects of junk-food on food-motivated behavior and nucleus accumbens glutamate plasticity; insights into the mechanism of calcium-permeable AMPA receptor recruitment. Neuropharmacology 2024; 242:109772. [PMID: 37898332 PMCID: PMC10883075 DOI: 10.1016/j.neuropharm.2023.109772] [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: 08/14/2023] [Revised: 10/03/2023] [Accepted: 10/17/2023] [Indexed: 10/30/2023]
Abstract
In rats, eating obesogenic diets increases calcium-permeable AMPA receptor (CP-AMPAR) transmission in the nucleus accumbens (NAc) core, and enhances food-motivated behavior. Interestingly, these diet-induced alterations in NAc transmission are pronounced and sustained in obesity-prone (OP) male rats and absent in obesity-resistant (OR) populations. However, effects of diet manipulation on food motivation, and the mechanisms underlying this NAc plasticity in OPs is unknown. Using male selectively-bred OP and OR rats, we assessed food-motivated behavior following ad lib access to chow (CH), junk-food (JF), or 10d of JF followed by a return to chow diet (JF-Dep). Motivation for food was greater in OP than OR rats, as expected. However, JF-Dep only produced enhancements in food-seeking in OP groups, while continuous JF access reduced food-seeking in both OPs and ORs. Additionally, optogenetic, chemogenetic, and pharmacological approaches were used to examine NAc CP-AMPAR recruitment following diet manipulation and ex vivo treatment of brain slices. Reducing excitatory transmission in the NAc was sufficient to recruit CP-AMPARs to synapses in OPs, but not ORs. In OPs, JF-induced increases in CP-AMPARs occurred in mPFC-, but not BLA-to-NAc inputs. Together results show that diet differentially affects behavioral and neural plasticity in obesity susceptible populations. We also identify conditions for acute recruitment of NAc CP-AMPARs; these results suggest that synaptic scaling mechanisms contribute to NAc CP-AMPAR recruitment. Overall, this work helps elucidate how diet interacts with obesity susceptibility to influence food-motivated behavior and extends our fundamental understanding of NAc CP-AMPAR recruitment.
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Affiliation(s)
- Tracy L Fetterly
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Amanda M Catalfio
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carrie R Ferrario
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA; Psychology Department (Biopsychology) University of Michigan, Ann Arbor, MI, 48109, USA.
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45
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Doorn N. Unraveling Dravet Syndrome: Exploring the complex effects of sodium channel mutations on neuronal networks. Sci Prog 2024; 107:368504231225076. [PMID: 38373395 PMCID: PMC10878221 DOI: 10.1177/00368504231225076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Dravet Syndrome (DS) is a severe developmental epileptic encephalopathy with frequent intractable seizures accompanied by cognitive impairment, often caused by pathogenic variants in SCN1A encoding sodium channel NaV1.1. Recent research utilizing in vitro patient-derived neuronal networks and accompanying in silico models uncovered that not just sodium-but also potassium-and synaptic currents were impaired in DS networks. Here, we explore the implications of these findings for three questions that remain elusive in DS: How do sodium channel impairments result in epilepsy? How can identical variants lead to varying phenotypes? What mechanisms underlie the developmental delay in DS patients? We speculate that impaired potassium currents might be a secondary effect to NaV1.1 mutations and could result in hyperexcitable neurons and epileptic networks. Moreover, we reason that homeostatic plasticity is actively engaged in DS networks, possibly affecting the phenotype and impairing learning and development when driven to extremes.
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Affiliation(s)
- Nina Doorn
- Department of Clinical Neurophysiology, University of Twente, Enschede, The Netherlands
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46
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Karbowski J, Urban P. Information encoded in volumes and areas of dendritic spines is nearly maximal across mammalian brains. Sci Rep 2023; 13:22207. [PMID: 38097675 PMCID: PMC10721930 DOI: 10.1038/s41598-023-49321-9] [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: 09/05/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023] Open
Abstract
Many experiments suggest that long-term information associated with neuronal memory resides collectively in dendritic spines. However, spines can have a limited size due to metabolic and neuroanatomical constraints, which should effectively limit the amount of encoded information in excitatory synapses. This study investigates how much information can be stored in the population of sizes of dendritic spines, and whether it is optimal in any sense. It is shown here, using empirical data for several mammalian brains across different regions and physiological conditions, that dendritic spines nearly maximize entropy contained in their volumes and surface areas for a given mean size in cortical and hippocampal regions. Although both short- and heavy-tailed fitting distributions approach [Formula: see text] of maximal entropy in the majority of cases, the best maximization is obtained primarily for short-tailed gamma distribution. We find that most empirical ratios of standard deviation to mean for spine volumes and areas are in the range [Formula: see text], which is close to the theoretical optimal ratios coming from entropy maximization for gamma and lognormal distributions. On average, the highest entropy is contained in spine length ([Formula: see text] bits per spine), and the lowest in spine volume and area ([Formula: see text] bits), although the latter two are closer to optimality. In contrast, we find that entropy density (entropy per spine size) is always suboptimal. Our results suggest that spine sizes are almost as random as possible given the constraint on their size, and moreover the general principle of entropy maximization is applicable and potentially useful to information and memory storing in the population of cortical and hippocampal excitatory synapses, and to predicting their morphological properties.
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Affiliation(s)
- Jan Karbowski
- Institute of Applied Mathematics and Mechanics, University of Warsaw, Warsaw, Poland.
| | - Paulina Urban
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Warsaw, Poland
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
- Laboratory of Databases and Business Analytics, National Information Processing Institute, National Research Institute, Warsaw, Poland
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47
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Koster KP, Flores-Barrera E, Artur de la Villarmois E, Caballero A, Tseng KY, Yoshii A. Loss of Depalmitoylation Disrupts Homeostatic Plasticity of AMPARs in a Mouse Model of Infantile Neuronal Ceroid Lipofuscinosis. J Neurosci 2023; 43:8317-8335. [PMID: 37884348 PMCID: PMC10711723 DOI: 10.1523/jneurosci.1113-23.2023] [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: 06/07/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023] Open
Abstract
Protein palmitoylation is the only reversible post-translational lipid modification. Palmitoylation is held in delicate balance by depalmitoylation to precisely regulate protein turnover. While over 20 palmitoylation enzymes are known, depalmitoylation is conducted by fewer enzymes. Of particular interest is the lack of the depalmitoylating enzyme palmitoyl-protein thioesterase 1 (PPT1) that causes the devastating pediatric neurodegenerative condition infantile neuronal ceroid lipofuscinosis (CLN1). While most of the research on Ppt1 function has centered on its role in the lysosome, recent findings demonstrated that many Ppt1 substrates are synaptic proteins, including the AMPA receptor (AMPAR) subunit GluA1. Still, the impact of Ppt1-mediated depalmitoylation on synaptic transmission and plasticity remains elusive. Thus, the goal of the present study was to use the Ppt1 -/- mouse model (both sexes) to determine whether Ppt1 regulates AMPAR-mediated synaptic transmission and plasticity, which are crucial for the maintenance of homeostatic adaptations in cortical circuits. Here, we found that basal excitatory transmission in the Ppt1 -/- visual cortex is developmentally regulated and that chemogenetic silencing of the Ppt1 -/- visual cortex excessively enhanced the synaptic expression of GluA1. Furthermore, triggering homeostatic plasticity in Ppt1 -/- primary neurons caused an exaggerated incorporation of GluA1-containing, calcium-permeable AMPARs, which correlated with increased GluA1 palmitoylation. Finally, Ca2+ imaging in awake Ppt1 -/- mice showed visual cortical neurons favor a state of synchronous firing. Collectively, our results elucidate a crucial role for Ppt1 in AMPAR trafficking and show that impeded proteostasis of palmitoylated synaptic proteins drives maladaptive homeostatic plasticity and abnormal recruitment of cortical activity in CLN1.SIGNIFICANCE STATEMENT Neuronal communication is orchestrated by the movement of receptors to and from the synaptic membrane. Protein palmitoylation is the only reversible post-translational lipid modification, a process that must be balanced precisely by depalmitoylation. The significance of depalmitoylation is evidenced by the discovery that mutation of the depalmitoylating enzyme palmitoyl-protein thioesterase 1 (Ppt1) causes severe pediatric neurodegeneration. In this study, we found that the equilibrium provided by Ppt1-mediated depalmitoylation is critical for AMPA receptor (AMPAR)-mediated plasticity and associated homeostatic adaptations of synaptic transmission in cortical circuits. This finding complements the recent explosion of palmitoylation research by emphasizing the necessity of balanced depalmitoylation.
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Affiliation(s)
- Kevin P Koster
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Eden Flores-Barrera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612
| | | | - Adriana Caballero
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Kuei Y Tseng
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Akira Yoshii
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612
- Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois 60612
- Department of Neurology, University of Illinois at Chicago, Chicago, Illinois 60612
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48
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Radulescu CI, Doostdar N, Zabouri N, Melgosa-Ecenarro L, Wang X, Sadeh S, Pavlidi P, Airey J, Kopanitsa M, Clopath C, Barnes SJ. Age-related dysregulation of homeostatic control in neuronal microcircuits. Nat Neurosci 2023; 26:2158-2170. [PMID: 37919424 PMCID: PMC10689243 DOI: 10.1038/s41593-023-01451-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/06/2023] [Indexed: 11/04/2023]
Abstract
Neuronal homeostasis prevents hyperactivity and hypoactivity. Age-related hyperactivity suggests homeostasis may be dysregulated in later life. However, plasticity mechanisms preventing age-related hyperactivity and their efficacy in later life are unclear. We identify the adult cortical plasticity response to elevated activity driven by sensory overstimulation, then test how plasticity changes with age. We use in vivo two-photon imaging of calcium-mediated cellular/synaptic activity, electrophysiology and c-Fos-activity tagging to show control of neuronal activity is dysregulated in the visual cortex in late adulthood. Specifically, in young adult cortex, mGluR5-dependent population-wide excitatory synaptic weakening and inhibitory synaptogenesis reduce cortical activity following overstimulation. In later life, these mechanisms are downregulated, so that overstimulation results in synaptic strengthening and elevated activity. We also find overstimulation disrupts cognition in older but not younger animals. We propose that specific plasticity mechanisms fail in later life dysregulating neuronal microcircuit homeostasis and that the age-related response to overstimulation can impact cognitive performance.
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Affiliation(s)
- Carola I Radulescu
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Nazanin Doostdar
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Nawal Zabouri
- Department of Biomedical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Leire Melgosa-Ecenarro
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Xingjian Wang
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Sadra Sadeh
- Department of Biomedical Engineering, Imperial College London, South Kensington Campus, London, UK
- Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Pavlina Pavlidi
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Joe Airey
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | | | - Claudia Clopath
- Department of Biomedical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Samuel J Barnes
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK.
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49
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Yuan X, Puvogel S, van Rhijn JR, Ciptasari U, Esteve-Codina A, Meijer M, Rouschop S, van Hugte EJH, Oudakker A, Schoenmaker C, Frega M, Schubert D, Franke B, Nadif Kasri N. A human in vitro neuronal model for studying homeostatic plasticity at the network level. Stem Cell Reports 2023; 18:2222-2239. [PMID: 37863044 PMCID: PMC10679660 DOI: 10.1016/j.stemcr.2023.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023] Open
Abstract
Mechanisms that underlie homeostatic plasticity have been extensively investigated at single-cell levels in animal models, but are less well understood at the network level. Here, we used microelectrode arrays to characterize neuronal networks following induction of homeostatic plasticity in human induced pluripotent stem cell (hiPSC)-derived glutamatergic neurons co-cultured with rat astrocytes. Chronic suppression of neuronal activity through tetrodotoxin (TTX) elicited a time-dependent network re-arrangement. Increased expression of AMPA receptors and the elongation of axon initial segments were associated with increased network excitability following TTX treatment. Transcriptomic profiling of TTX-treated neurons revealed up-regulated genes related to extracellular matrix organization, while down-regulated genes related to cell communication; also astrocytic gene expression was found altered. Overall, our study shows that hiPSC-derived neuronal networks provide a reliable in vitro platform to measure and characterize homeostatic plasticity at network and single-cell levels; this platform can be extended to investigate altered homeostatic plasticity in brain disorders.
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Affiliation(s)
- Xiuming Yuan
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Sofía Puvogel
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Jon-Ruben van Rhijn
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Ummi Ciptasari
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
| | - Mandy Meijer
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Simon Rouschop
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Eline J H van Hugte
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Astrid Oudakker
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Chantal Schoenmaker
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Monica Frega
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, the Netherlands
| | - Dirk Schubert
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Barbara Franke
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands.
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50
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Cain SM, Alles SRA, Gopaul R, Bernier LP, Yung AC, Bauman A, Yang Y, Baker GB, Kozlowski P, MacVicar BA, Snutch TP. Chronic pregabalin treatment protects against spreading depolarization and alters hippocampal synaptic characteristics in a model of familial hemiplegic migraine-type 1. Mol Brain 2023; 16:76. [PMID: 37924146 PMCID: PMC10623724 DOI: 10.1186/s13041-023-01062-6] [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: 04/25/2023] [Accepted: 10/04/2023] [Indexed: 11/06/2023] Open
Abstract
Familial hemiplegic migraine type-1 (FHM-1) is a form of migraine with aura caused by mutations in the P/Q-type (Cav2.1) voltage-gated calcium channel. Pregabalin, used clinically in the treatment of chronic pain and epilepsy, inhibits P/Q-type calcium channel activity and recent studies suggest that it may have potential for the treatment of migraine. Spreading Depolarization (SD) is a neurophysiological phenomenon that can occur during migraine with aura by propagating a wave of silenced neuronal function through cortex and sometimes subcortical brain structures. Here, utilizing an optogenetic stimulation technique optimized to allow for non-invasive initiation of cortical SD, we demonstrate that chronic pregabalin administration [12 mg/kg/day (s.c.)] in vivo increased the threshold for cortical spreading depolarization in transgenic mice harboring the clinically-relevant Cav2.1S218L mutation (S218L). In addition, chronic pregabalin treatment limited subcortical propagation of recurrent spreading depolarization events to the striatum and hippocampus in both wild-type and S218L mice. To examine contributing underlying mechanisms of action of chronic pregabalin, we performed whole-cell patch-clamp electrophysiology in CA1 neurons in ex vivo brain slices from mice treated with chronic pregabalin vs vehicle. In WT mice, chronic pregabalin produced a decrease in spontaneous excitatory postsynaptic current (sEPSC) amplitude with no effect on frequency. In contrast, in S218L mice chronic pregabalin produced an increase in sEPSC amplitude and decreased frequency. These electrophysiological findings suggest that in FHM-1 mice chronic pregabalin acts through both pre- and post-synaptic mechanisms in CA1 hippocampal neurons to elicit FHM-1 genotype-specific inhibitory action. The results highlight the potential of chronic pregabalin to limit recurrent SD to subcortical brain structures during pathophysiological events in both the genetically-normal and FHM-1 brain. The work further provides insights into FHM-1 pathophysiology and the potential for chronic pregabalin treatment to prevent SD in migraineurs.
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Affiliation(s)
- Stuart M Cain
- Michael Smith Laboratories, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada
| | - Sascha R A Alles
- Michael Smith Laboratories, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Ray Gopaul
- Michael Smith Laboratories, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada
| | - Louis-Philippe Bernier
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada
| | - Andrew C Yung
- UBC MRI Research Facility, University of British Columbia, Vancouver, Canada
| | - Andrew Bauman
- UBC MRI Research Facility, University of British Columbia, Vancouver, Canada
| | - Yi Yang
- Michael Smith Laboratories, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada
| | - Glen B Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Canada
| | - Piotr Kozlowski
- UBC MRI Research Facility, University of British Columbia, Vancouver, Canada
| | - Brian A MacVicar
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, Canada.
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