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Olson RJ, Bartlett L, Sonneborn A, Milton R, Bretton-Granatoor Z, Firdous A, Harris AZ, Abbas AI. Decoupling of cortical activity from behavioral state following administration of the classic psychedelic DOI. Neuropharmacology 2024; 257:110030. [PMID: 38851531 DOI: 10.1016/j.neuropharm.2024.110030] [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: 12/19/2023] [Revised: 05/02/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
Administration or consumption of classic psychedelics (CPs) leads to profound changes in experience which are often described as highly novel and meaningful. They have shown substantial promise in treating depressive symptoms and may be therapeutic in other situations. Although research suggests that the therapeutic response is correlated with the intensity of the experience, the neural circuit basis for the alterations in experience caused by CPs requires further study. The medial prefrontal cortex (mPFC), where CPs have been shown to induce rapid, 5-HT2A receptor-dependent structural and neurophysiological changes, is believed to be a key site of action. To investigate the acute neural circuit changes induced by CPs, we recorded single neurons and local field potentials in the mPFC of freely behaving male mice after administration of the 5-HT2A/2C receptor-selective CP, 2,5-Dimethoxy-4-iodoamphetamine (DOI). We segregated recordings into active and rest periods in order to examine cortical activity during desynchronized (active) and synchronized (rest) states. We found that DOI induced a robust decrease in low frequency power when animals were at rest, attenuating the usual synchronization that occurs during less active behavioral states. DOI also increased broadband gamma power and suppressed activity in fast-spiking neurons in both active and rest periods. Together, these results suggest that the CP DOI induces persistent desynchronization in mPFC, including during rest when mPFC typically exhibits more synchronized activity. This shift in cortical dynamics may in part underlie the longer-lasting effects of CPs on plasticity, and may be critical to their therapeutic properties.
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Affiliation(s)
- Randall J Olson
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR 97239, USA
| | - Lowell Bartlett
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR 97239, USA
| | - Alex Sonneborn
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR 97239, USA
| | - Russell Milton
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR 97239, USA
| | | | - Ayesha Firdous
- Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY 10034, USA
| | - Alexander Z Harris
- Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY 10034, USA; Department of Psychiatry, Columbia University, New York, NY, 10034, USA
| | - Atheir I Abbas
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR 97239, USA; Department of Psychiatry, Oregon Health and Science University, Portland OR 97239, USA; VA Portland Health Care System, Portland OR, 97239, USA.
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2
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De Filippo R, Schmitz D. Synthetic surprise as the foundation of the psychedelic experience. Neurosci Biobehav Rev 2024; 157:105538. [PMID: 38220035 PMCID: PMC10839673 DOI: 10.1016/j.neubiorev.2024.105538] [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: 09/18/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
Psychedelic agents, such as LSD and psilocybin, induce marked alterations in consciousness via activation of the 5-HT2A receptor (5-HT2ARs). We hypothesize that psychedelics enforce a state of synthetic surprise through the biased activation of the 5-HTRs system. This idea is informed by recent insights into the role of 5-HT in signaling surprise. The effects on consciousness, explained by the cognitive penetrability of perception, can be described within the predictive coding framework where surprise corresponds to prediction error, the mismatch between predictions and actual sensory input. Crucially, the precision afforded to the prediction error determines its effect on priors, enabling a dynamic interaction between top-down expectations and incoming sensory data. By integrating recent findings on predictive coding circuitry and 5-HT2ARs transcriptomic data, we propose a biological implementation with emphasis on the role of inhibitory interneurons. Implications arise for the clinical use of psychedelics, which may rely primarily on their inherent capacity to induce surprise in order to disrupt maladaptive patterns.
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Affiliation(s)
- Roberto De Filippo
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany.
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Einstein Center for Neuroscience, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Humboldt-Universität zu Berlin, Bernstein Center for Computational Neuroscience, Philippstr. 13, 10115 Berlin, Germany
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3
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Carlos-Lima E, Higa GSV, Viana FJC, Tamais AM, Cruvinel E, Borges FDS, Francis-Oliveira J, Ulrich H, De Pasquale R. Serotonergic Modulation of the Excitation/Inhibition Balance in the Visual Cortex. Int J Mol Sci 2023; 25:519. [PMID: 38203689 PMCID: PMC10778629 DOI: 10.3390/ijms25010519] [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: 09/13/2023] [Revised: 12/18/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Serotonergic neurons constitute one of the main systems of neuromodulators, whose diffuse projections regulate the functions of the cerebral cortex. Serotonin (5-HT) is known to play a crucial role in the differential modulation of cortical activity related to behavioral contexts. Some features of the 5-HT signaling organization suggest its possible participation as a modulator of activity-dependent synaptic changes during the critical period of the primary visual cortex (V1). Cells of the serotonergic system are among the first neurons to differentiate and operate. During postnatal development, ramifications from raphe nuclei become massively distributed in the visual cortical area, remarkably increasing the availability of 5-HT for the regulation of excitatory and inhibitory synaptic activity. A substantial amount of evidence has demonstrated that synaptic plasticity at pyramidal neurons of the superficial layers of V1 critically depends on a fine regulation of the balance between excitation and inhibition (E/I). 5-HT could therefore play an important role in controlling this balance, providing the appropriate excitability conditions that favor synaptic modifications. In order to explore this possibility, the present work used in vitro intracellular electrophysiological recording techniques to study the effects of 5-HT on the E/I balance of V1 layer 2/3 neurons, during the critical period. Serotonergic action on the E/I balance has been analyzed on spontaneous activity, evoked synaptic responses, and long-term depression (LTD). Our results pointed out that the predominant action of 5-HT implies a reduction in the E/I balance. 5-HT promoted LTD at excitatory synapses while blocking it at inhibitory synaptic sites, thus shifting the Hebbian alterations of synaptic strength towards lower levels of E/I balance.
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Affiliation(s)
- Estevão Carlos-Lima
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
- Departamento de Bioquímica, Instituto de Química (USP), São Paulo 05508-900, SP, Brazil;
- Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo 09210-580, SP, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Alicia Moraes Tamais
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
| | - Fernando da Silva Borges
- Department of Physiology & Pharmacology, SUNY Downstate Health Sciences University, New York, NY 11203, USA;
| | - José Francis-Oliveira
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), São Paulo 05508-900, SP, Brazil;
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo 05508-000, SP, Brazil; (E.C.-L.); (G.S.V.H.); (E.C.); (J.F.-O.)
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4
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Scheuer KS, Jansson AM, Zhao X, Jackson MB. Inter and Intralaminar Excitation of Parvalbumin Interneurons in Mouse Barrel Cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543448. [PMID: 37398428 PMCID: PMC10312540 DOI: 10.1101/2023.06.02.543448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Parvalbumin (PV) interneurons are inhibitory fast-spiking cells with essential roles in directing the flow of information through cortical circuits. These neurons set the balance between excitation and inhibition, control rhythmic activity, and have been linked to disorders including autism spectrum and schizophrenia. PV interneurons differ between cortical layers in their morphology, circuitry, and function, but how their electrophysiological properties vary has received little attention. Here we investigate responses of PV interneurons in different layers of primary somatosensory barrel cortex (BC) to different excitatory inputs. With the genetically-encoded hybrid voltage sensor, hVOS, we recorded voltage changes simultaneously in many L2/3 and L4 PV interneurons to stimulation in either L2/3 or L4. Decay-times were consistent across L2/3 and L4. Amplitude, half-width, and rise-time were greater for PV interneurons residing in L2/3 compared to L4. Stimulation in L2/3 elicited responses in both L2/3 and L4 with longer latency compared to stimulation in L4. These differences in latency between layers could influence their windows for temporal integration. Thus PV interneurons in different cortical layers of BC show differences in response properties with potential roles in cortical computations.
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Affiliation(s)
- Kate S Scheuer
- Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, Wisconsin, 53705
| | - Anna M Jansson
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, 53705
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, 53705
| | - Meyer B Jackson
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, 53705
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5
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Tang ZH, Yu ZP, Li Q, Zhang XQ, Muhetaer K, Wang ZC, Xu P, Shen HW. The effects of serotonergic psychedelics in synaptic and intrinsic properties of neurons in layer II/III of the orbitofrontal cortex. Psychopharmacology (Berl) 2023; 240:1275-1285. [PMID: 37071130 DOI: 10.1007/s00213-023-06366-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/06/2023] [Indexed: 04/19/2023]
Abstract
RATIONALE Serotonergic psychedelics show promise in the treatment of psychiatric disorders, including obsessive-compulsive disorder. Dysfunction of the orbitofrontal cortex (OFc) has been implicated in the pathophysiology of compulsive behavior, which might be a key region for the efficacy of psychedelics. However, the effects of psychedelics on the neural activities and local excitation/inhibition (E/I) balance in the OFc are unclear. OBJECTIVES This study aimed to investigate how 25C-NBOMe, a substituted phenethylamine psychedelic, regulated the synaptic and intrinsic properties of neurons in layer II/III of the OFc. METHODS Acute brain slices containing the OFc of adult male Sprague Dawley rats were used for ex vivo whole-cell recording. The synaptic and intrinsic properties of neurons were monitored using voltage and current clamps, respectively. Electrically evoked action potential (eAP) was used to measure synaptic-driven pyramidal activity. RESULTS 25C-NBOMe enhanced spontaneous neurotransmission at glutamatergic synapses but diminished that in GABAergic synapses through the 5-HT2A receptor. 25C-NBOMe also increased both evoked excitatory currents and evoked action potentials. Moreover, 25C-NBOMe promoted the excitability of pyramidal neurons but not fast-spiking neurons. Either inhibiting G protein-gated inwardly rectifying potassium channels or activating protein kinase C significantly obstructed the facilitative effect of 25C-NBOMe on the intrinsic excitability of pyramidal neurons. CONCLUSIONS This work reveals the multiple roles of 25C-NBOMe in modulating synaptic and neuronal function in the OFc, which collectively promotes local E/I ratios.
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Affiliation(s)
- Zi-Hang Tang
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
| | - Zhi-Peng Yu
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
- Faculty of Electrical Engineering and Computer Science, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
| | - Qiong Li
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
| | - Xiao-Qin Zhang
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
| | - Kadeliya Muhetaer
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
| | - Zheng-Chun Wang
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China
| | - Peng Xu
- Key Laboratory of Drug Monitoring and Control, Drug Intelligence and Forensic Center, Ministry of Public Security, Beijing, 100093, People's Republic of China
| | - Hao-Wei Shen
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, 818 Fenghua Rd, Ningbo, Zhejiang, 315211, People's Republic of China.
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, 315010, People's Republic of China.
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6
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Smausz R, Neill J, Gigg J. Neural mechanisms underlying psilocybin's therapeutic potential - the need for preclinical in vivo electrophysiology. J Psychopharmacol 2022; 36:781-793. [PMID: 35638159 PMCID: PMC9247433 DOI: 10.1177/02698811221092508] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Psilocybin is a naturally occurring psychedelic compound with profound perception-, emotion- and cognition-altering properties and great potential for treating brain disorders. However, the neural mechanisms mediating its effects require in-depth investigation as there is still much to learn about how psychedelic drugs produce their profound and long-lasting effects. In this review, we outline the current understanding of the neurophysiology of psilocybin's psychoactive properties, highlighting the need for additional preclinical studies to determine its effect on neural network dynamics. We first describe how psilocybin's effect on brain regions associated with the default-mode network (DMN), particularly the prefrontal cortex and hippocampus, likely plays a key role in mediating its consciousness-altering properties. We then outline the specific receptor and cell types involved and discuss contradictory evidence from neuroimaging studies regarding psilocybin's net effect on activity within these regions. We go on to argue that in vivo electrophysiology is ideally suited to provide a more holistic, neural network analysis approach to understand psilocybin's mode of action. Thus, we integrate information about the neural bases for oscillatory activity generation with the accumulating evidence about psychedelic drug effects on neural synchrony within DMN-associated areas. This approach will help to generate important questions for future preclinical and clinical studies. Answers to these questions are vital for determining the neural mechanisms mediating psilocybin's psychotherapeutic potential, which promises to improve outcomes for patients with severe depression and other difficulty to treat conditions.
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Affiliation(s)
- Rebecca Smausz
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK
| | - Joanna Neill
- Division of Pharmacy and
Optometry, Faculty of Biology, Medicine and Health, The University of
Manchester, Manchester, UK,Medical Psychedelics Working
Group, Drug Science, UK
| | - John Gigg
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK,John Gigg, Division of Neuroscience
and Experimental Psychology, Faculty of Biology, Medicine and Health,
The University of Manchester, Manchester, M13 9PT, UK.
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7
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5-HT2A receptor dysregulation in a schizophrenia relevant mouse model of NMDA receptor hypofunction. Transl Psychiatry 2022; 12:168. [PMID: 35459266 PMCID: PMC9033804 DOI: 10.1038/s41398-022-01930-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 03/22/2022] [Accepted: 04/08/2022] [Indexed: 11/30/2022] Open
Abstract
Blockade of N-methyl-D-aspartate receptors (NMDAR) is known to augment cortical serotonin 2A receptors (5-HT2ARs), which is implicated in psychosis. However, the pathways from NMDAR hypofunction to 5-HT2AR up-regulation are unclear. Here we addressed in mice whether genetic deletion of the indispensable NMDAR-subunit Grin1 principally in corticolimbic parvalbumin-positive fast-spiking interneurons, could up-regulate 5-HT2ARs leading to cortical hyper-excitability. First, in vivo local-field potential recording revealed that auditory cortex in Grin1 mutant mice became hyper-excitable upon exposure to acoustic click-train stimuli that release 5-HT in the cortex. This excitability increase was reproduced ex vivo where it consisted of an increased frequency of action potential (AP) firing in layer 2/3 pyramidal neurons of mutant auditory cortex. Application of the 5-HT2AR agonist TCB-2 produced similar results. The effect of click-trains was reversed by the 5-HT2AR antagonist M100907 both in vivo and ex vivo. Increase in AP frequency of pyramidal neurons was also reversed by application of Gαq protein inhibitor BIM-46187 and G protein-gated inwardly-rectifying K+ (GIRK) channel activator ML297. In fast-spiking interneurons, 5-HT2AR activation normally promotes GABA release, contributing to decreased excitability of postsynaptic pyramidal neurons, which was missing in the mutants. Moreover, unlike the controls, the GABAA receptor antagonist (+)-bicuculline had little effect on AP frequency of mutant pyramidal neurons, indicating a disinhibition state. These results suggest that the auditory-induced hyper-excitable state is conferred via GABA release deficits from Grin1-lacking interneurons leading to 5-HT2AR dysregulation and GIRK channel suppression in cortical pyramidal neurons, which could be involved in auditory psychosis.
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8
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Pfeiffer P, Barreda Tomás FJ, Wu J, Schleimer JH, Vida I, Schreiber S. A dynamic clamp protocol to artificially modify cell capacitance. eLife 2022; 11:75517. [PMID: 35362411 PMCID: PMC9135398 DOI: 10.7554/elife.75517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
Dynamics of excitable cells and networks depend on the membrane time constant, set by membrane resistance and capacitance. Whereas pharmacological and genetic manipulations of ionic conductances of excitable membranes are routine in electrophysiology, experimental control over capacitance remains a challenge. Here, we present capacitance clamp, an approach that allows electrophysiologists to mimic a modified capacitance in biological neurons via an unconventional application of the dynamic clamp technique. We first demonstrate the feasibility to quantitatively modulate capacitance in a mathematical neuron model and then confirm the functionality of capacitance clamp in in vitro experiments in granule cells of rodent dentate gyrus with up to threefold virtual capacitance changes. Clamping of capacitance thus constitutes a novel technique to probe and decipher mechanisms of neuronal signaling in ways that were so far inaccessible to experimental electrophysiology.
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Affiliation(s)
- Paul Pfeiffer
- Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Jiameng Wu
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jan-Hendrik Schleimer
- Institute of Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne Schreiber
- Institute of Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
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9
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Grossman CD, Cohen JY. Neuromodulation and Neurophysiology on the Timescale of Learning and Decision-Making. Annu Rev Neurosci 2022; 45:317-337. [PMID: 35363533 DOI: 10.1146/annurev-neuro-092021-125059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nervous systems evolved to effectively navigate the dynamics of the environment to achieve their goals. One framework used to study this fundamental problem arose in the study of learning and decision-making. In this framework, the demands of effective behavior require slow dynamics-on the scale of seconds to minutes-of networks of neurons. Here, we review the phenomena and mechanisms involved. Using vignettes from a few species and areas of the nervous system, we view neuromodulators as key substrates for temporal scaling of neuronal dynamics. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Cooper D Grossman
- The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, and Kavli Neuroscience Discovery Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;
| | - Jeremiah Y Cohen
- The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, and Kavli Neuroscience Discovery Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;
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10
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Sohal VS. Transforming Discoveries About Cortical Microcircuits and Gamma Oscillations Into New Treatments for Cognitive Deficits in Schizophrenia. Am J Psychiatry 2022; 179:267-276. [PMID: 35360913 DOI: 10.1176/appi.ajp.20220147] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The major cause of disability in schizophrenia is cognitive impairment, which remains largely refractory to existing treatments. This reflects the fact that antipsychotics and other therapies have not been designed to address specific brain abnormalities that cause cognitive impairment. This overview proposes that understanding how specific cellular and synaptic loci within cortical microcircuits contribute to cortical gamma oscillations may reveal treatments for cognitive impairment. Gamma oscillations are rhythmic patterns of high frequency (∼30-100 Hz) neuronal activity that are synchronized within and across brain regions, generated by a class of inhibitory interneurons that express parvalbumin, and recruited during a variety of cognitive tasks. In schizophrenia, both parvalbumin interneuron function and task-evoked gamma oscillations are deficient. While it has long been controversial whether gamma oscillations are merely a biomarker of circuit function or actually contribute to information processing by neuronal networks, recent neurobiological studies in mice have shown that disrupting or enhancing synchronized gamma oscillations can reproduce or ameliorate cognitive deficits resembling those seen in schizophrenia. In fact, transiently enhancing the synchrony of parvalbumin interneuron-generated gamma oscillations can lead to long-lasting improvements in cognition in mice that model aspects of schizophrenia. Gamma oscillations emerge from specific patterns of connections between a variety of cell types within cortical microcircuits. Thus, a critical next step is to understand how specific cell types and synapses generate gamma oscillations, mediate the effects of gamma oscillations on information processing, and/or undergo plasticity following the induction of gamma oscillations. Modulating these circuit loci, potentially in combination with other approaches such as cognitive training and brain stimulation, may yield potent and selective interventions for enhancing cognition in schizophrenia.
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Affiliation(s)
- Vikaas S Sohal
- Department of Psychiatry and Behavioral Sciences, Weill Institute for Neurosciences, and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco
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11
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Transcriptomically-Guided Pharmacological Experiments in Neocortical and Hippocampal NPY-Positive GABAergic Interneurons. eNeuro 2022; 9:ENEURO.0005-22.2022. [PMID: 35437266 PMCID: PMC9045474 DOI: 10.1523/eneuro.0005-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/25/2022] [Accepted: 03/30/2022] [Indexed: 12/13/2022] Open
Abstract
Cortical GABAergic interneurons have been shown to fulfil important roles by inhibiting excitatory principal neurons. Recent transcriptomic studies have confirmed seminal discoveries that used anatomic and electrophysiological methods highlighting the existence of multiple different classes of GABAergic interneurons. Although some of these studies have emphasized that inter-regional differences may exist for a given class, the extent of such differences remains unknown. To address this problem, we used single-cell Patch-RNAseq to characterize neuropeptide Y (NPY)-positive GABAergic interneurons in superficial layers of the primary auditory cortex (AC) and in distal layers of area CA3 in mice. We found that more than 300 genes are differentially expressed in NPY-positive neurons between these two brain regions. For example, the AMPA receptor (AMPAR) auxiliary subunit Shisa9/CKAMP44 and the 5HT2a receptor (5HT2aR) are significantly higher expressed in auditory NPY-positive neurons. These findings guided us to perform pharmacological experiments that revealed a role for 5HT2aRs in auditory NPY-positive neurons. Specifically, although the application of 5HT led to a depolarization of both auditory and CA3 NPY-positive neurons, the 5HT2aR antagonist ketanserin only reversed membrane potential changes in auditory NPY-positive neurons. Our study demonstrates the potential of single-cell transcriptomic studies in guiding directed pharmacological experiments.
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12
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Wang Y, Zhang Y, Wang K, Zhu Z, Wang D, Yang Q, Dong H. Esketamine Increases Neurotransmitter Releases but Simplifies Neurotransmitter Networks in Mouse Prefrontal Cortex. J Neurophysiol 2022; 127:586-595. [PMID: 35080449 DOI: 10.1152/jn.00462.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
General anesthesia induces a profound but reversible unconscious state, which is accompanied by changes in various neurotransmitters in the cortex. Unlike the "brain silencing" effect of γ-aminobutyric acid (GABA) receptor potentiator anesthesia, ketamine anesthesia leads the brain to a paradoxical active state with higher cortical activity, which is manifested as dissociative anesthesia. However, how the overall neurotransmitter network evolves across conscious states after ketamine administration remains unclear. Using in vivo microdialysis, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis, and electroencephalogram (EEG) recording technique, we continuously measured the concentrations of six neurotransmitters and the EEG signals during anesthesia with esketamine, an S-enantiomer of ketamine racemate. We found that there was an increase in the release of five cortical neurotransmitters after the administration of esketamine. The correlation of cortical neurotransmitters was dynamically simplified along with behavioral changes until full recovery after anesthesia. The esketamine-increased gamma oscillation power was positively correlated only with the concentration of 5-hydroxytryptamine (5-HT) in the medial prefrontal cortex. This study suggests that the transformation of the neurotransmitter network rather than the concentrations of neurotransmitters could be more indicative of the consciousness shift during esketamine anesthesia.
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Affiliation(s)
- Ye Wang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yunyun Zhang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Kai Wang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Zhenghua Zhu
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Dan Wang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Qianzi Yang
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Hailong Dong
- Department of Anaesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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13
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Yan Z, Rein B. Mechanisms of synaptic transmission dysregulation in the prefrontal cortex: pathophysiological implications. Mol Psychiatry 2022; 27:445-465. [PMID: 33875802 PMCID: PMC8523584 DOI: 10.1038/s41380-021-01092-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 03/13/2021] [Accepted: 03/29/2021] [Indexed: 02/02/2023]
Abstract
The prefrontal cortex (PFC) serves as the chief executive officer of the brain, controlling the highest level cognitive and emotional processes. Its local circuits among glutamatergic principal neurons and GABAergic interneurons, as well as its long-range connections with other brain regions, have been functionally linked to specific behaviors, ranging from working memory to reward seeking. The efficacy of synaptic signaling in the PFC network is profundedly influenced by monoaminergic inputs via the activation of dopamine, adrenergic, or serotonin receptors. Stress hormones and neuropeptides also exert complex effects on the synaptic structure and function of PFC neurons. Dysregulation of PFC synaptic transmission is strongly linked to social deficits, affective disturbance, and memory loss in brain disorders, including autism, schizophrenia, depression, and Alzheimer's disease. Critical neural circuits, biological pathways, and molecular players that go awry in these mental illnesses have been revealed by integrated electrophysiological, optogenetic, biochemical, and transcriptomic studies of PFC. Novel epigenetic mechanism-based strategies are proposed as potential avenues of therapeutic intervention for PFC-involved diseases. This review provides an overview of PFC network organization and synaptic modulation, as well as the mechanisms linking PFC dysfunction to the pathophysiology of neurodevelopmental, neuropsychiatric, and neurodegenerative diseases. Insights from the preclinical studies offer the potential for discovering new medical treatments for human patients with these brain disorders.
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Affiliation(s)
- Zhen Yan
- Department of Physiology and Biophysics, State University of New York at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA.
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14
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Bryson A, Berkovic SF, Petrou S, Grayden DB. State transitions through inhibitory interneurons in a cortical network model. PLoS Comput Biol 2021; 17:e1009521. [PMID: 34653178 PMCID: PMC8550371 DOI: 10.1371/journal.pcbi.1009521] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 10/27/2021] [Accepted: 10/04/2021] [Indexed: 11/18/2022] Open
Abstract
Inhibitory interneurons shape the spiking characteristics and computational properties of cortical networks. Interneuron subtypes can precisely regulate cortical function but the roles of interneuron subtypes for promoting different regimes of cortical activity remains unclear. Therefore, we investigated the impact of fast spiking and non-fast spiking interneuron subtypes on cortical activity using a network model with connectivity and synaptic properties constrained by experimental data. We found that network properties were more sensitive to modulation of the fast spiking population, with reductions of fast spiking excitability generating strong spike correlations and network oscillations. Paradoxically, reduced fast spiking excitability produced a reduction of global excitation-inhibition balance and features of an inhibition stabilised network, in which firing rates were driven by the activity of excitatory neurons within the network. Further analysis revealed that the synaptic interactions and biophysical features associated with fast spiking interneurons, in particular their rapid intrinsic response properties and short synaptic latency, enabled this state transition by enhancing gain within the excitatory population. Therefore, fast spiking interneurons may be uniquely positioned to control the strength of recurrent excitatory connectivity and the transition to an inhibition stabilised regime. Overall, our results suggest that interneuron subtypes can exert selective control over excitatory gain allowing for differential modulation of global network state. Inhibitory interneurons comprise a significant proportion of all cortical neurons and play a crucial role in sustaining normal neural activity in the brain. Although it is well established that there exist distinct subtypes of interneurons, the impact of different interneuron subtypes upon cortical function remains unclear. In this work, we explore the role of interneuron subtypes for modulating neural activity using a network model containing two of the most common interneuron subtypes. We find that one interneuron subtype, known as fast spiking interneurons, preferentially control the strength of activity between excitatory neurons to regulate changes in network state. These findings suggest that interneuron subtypes may selectively modulate cortical activity to promote different computational capabilities.
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Affiliation(s)
- Alexander Bryson
- Ion Channels and Disease Group, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
- Department of Neurology, Austin Health, Heidelberg, Australia
- * E-mail: (AB); (DBG)
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Australia
| | - Steven Petrou
- Ion Channels and Disease Group, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
| | - David B. Grayden
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Australia
- * E-mail: (AB); (DBG)
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15
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Interactions among diameter, myelination, and the Na/K pump affect axonal resilience to high-frequency spiking. Proc Natl Acad Sci U S A 2021; 118:2105795118. [PMID: 34353911 PMCID: PMC8364126 DOI: 10.1073/pnas.2105795118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The reliability of spike propagation in axons is determined by complex interactions among ionic currents, ion pumps, and morphological properties. We use compartment-based modeling to reveal that interactions of diameter, myelination, and the Na/K pump determine the reliability of high-frequency spike propagation. By acting as a “reservoir” of nodal Na+ influx, myelinated compartments efficiently increase propagation reliability. Although spike broadening was thought to oppose fast spiking, its effect on spike propagation is complicated, depending on the balance of Na+ channel inactivation gate recovery, Na+ influx, and axial charge. Our findings suggest that slow Na+ removal influences axonal resilience to high-frequency spike propagation and that different strategies may be required to overcome this constraint in different neurons. Axons reliably conduct action potentials between neurons and/or other targets. Axons have widely variable diameters and can be myelinated or unmyelinated. Although the effect of these factors on propagation speed is well studied, how they constrain axonal resilience to high-frequency spiking is incompletely understood. Maximal firing frequencies range from ∼1 Hz to >300 Hz across neurons, but the process by which Na/K pumps counteract Na+ influx is slow, and the extent to which slow Na+ removal is compatible with high-frequency spiking is unclear. Modeling the process of Na+ removal shows that large-diameter axons are more resilient to high-frequency spikes than are small-diameter axons, because of their slow Na+ accumulation. In myelinated axons, the myelinated compartments between nodes of Ranvier act as a “reservoir” to slow Na+ accumulation and increase the reliability of axonal propagation. We now find that slowing the activation of K+ current can increase the Na+ influx rate, and the effect of minimizing the overlap between Na+ and K+ currents on spike propagation resilience depends on complex interactions among diameter, myelination, and the Na/K pump density. Our results suggest that, in neurons with different channel gating kinetic parameters, different strategies may be required to improve the reliability of axonal propagation.
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Effects of Withdrawal from Cocaine Self-Administration on Rat Orbitofrontal Cortex Parvalbumin Neurons Expressing Cre recombinase: Sex-Dependent Changes in Neuronal Function and Unaltered Serotonin Signaling. eNeuro 2021; 8:ENEURO.0017-21.2021. [PMID: 34083381 PMCID: PMC8266218 DOI: 10.1523/eneuro.0017-21.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 11/21/2022] Open
Abstract
The orbitofrontal cortex (OFC) is a brain region involved in higher-order decision-making. Rodent studies show that cocaine self-administration (CSA) reduces OFC contribution to goal-directed behavior and behavioral strategies to avoid drug intake. This change in OFC function persists for many weeks after cocaine withdrawal, suggesting involvement in the process of addiction. The mechanisms underlying impaired OFC function by cocaine are not well-understood. However, studies implicate altered OFC serotonin (5-HT) function in disrupted cognitive processes during addiction and other psychiatric disorders. Thus, it is hypothesized that cocaine impairment of OFC function involves changes in 5-HT signaling, and previous work shows that 5-HT1A and 5-HT2A receptor-mediated effects on OFC pyramidal neurons (PyNs) are impaired weeks after cocaine withdrawal. However, 5-HT effects on other contributors to OFC circuit function have not been fully investigated, including the parvalbumin-containing, fast-spiking interneurons (OFCPV), whose function is essential to normal OFC-mediated behavior. Here, 5-HT function in naive rats and those withdrawn from CSA were evaluated using a novel rat transgenic line in which the rat parvalbumin promoter drives Cre-recombinase expression to permit identification of OFCPV cells by fluorescent reporter protein expression. We find that whereas CSA altered basal synaptic and membrane properties of the OFCPV neurons in a sex-dependent manner, the effects of 5-HT on these cells were unchanged by CSA. These data suggest that the behavioral effects of dysregulated OFC 5-HT function caused by cocaine experience are primarily mediated by changes in 5-HT signaling at PyNs, and not at OFCPV neurons.
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17
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Pereyra AE, Mininni CJ, Zanutto BS. Information capacity and robustness of encoding in the medial prefrontal cortex are modulated by the bioavailability of serotonin and the time elapsed from the cue during a reward-driven task. Sci Rep 2021; 11:13882. [PMID: 34230550 PMCID: PMC8260631 DOI: 10.1038/s41598-021-93313-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023] Open
Abstract
Serotonin (5-HT) is a key neuromodulator of medial prefrontal cortex (mPFC) functions. Pharmacological manipulation of systemic 5-HT bioavailability alters the electrical activity of mPFC neurons. However, 5-HT modulation at the population level is not well characterized. In the present study, we made single neuron extracellular recordings in the mPFC of rats performing an operant conditioning task, and analyzed the effect of systemic administration of fluoxetine (a selective serotonin reuptake inhibitor) on the information encoded in the firing activity of the neural population. Chronic (longer than 15 days), but not acute (less than 15 days), fluoxetine administration reduced the firing rate of mPFC neurons. Moreover, fluoxetine treatment enhanced pairwise entropy but diminished noise correlation and redundancy in the information encoded, thus showing how mPFC differentially encodes information as a function of 5-HT bioavailability. Information about the occurrence of the reward-predictive stimulus was maximized during reward consumption, around 3 to 4 s after the presentation of the cue, and it was higher under chronic fluoxetine treatment. However, the encoded information was less robust to noise corruption when compared to control conditions.
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Affiliation(s)
- A Ezequiel Pereyra
- Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina.
| | - Camilo J Mininni
- Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina
| | - B Silvano Zanutto
- Instituto de Biología y Medicina Experimental (IBYME), CONICET, Buenos Aires, Argentina
- Universidad de Buenos Aires, Facultad de Ingeniería, Instituto de Ingeniería Biomédica, Buenos Aires, Argentina
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18
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Yalcinbas EA, Cazares C, Gremel CM. Call for a more balanced approach to understanding orbital frontal cortex function. Behav Neurosci 2021; 135:255-266. [PMID: 34060878 DOI: 10.1037/bne0000450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Orbital frontal cortex (OFC) research has historically emphasized the function of this associative cortical area within top-down theoretical frameworks. This approach has largely focused on mapping OFC activity onto human-defined psychological or cognitive constructs and has often led to OFC circuitry bearing the weight of entire theoretical frameworks. New techniques and tools developed in the last decade have made it possible to revisit long-standing basic science questions in neuroscience and answer them with increasing sophistication. We can now study and specify the genetic, molecular, cellular, and circuit architecture of a brain region in much greater detail, which allows us to piece together how they contribute to emergent circuit functions. For instance, adopting such systematic and unbiased bottom-up approaches to elucidating the function of the visual system has paved the way to building a greater understanding of the spectrum of its computational capabilities. In the same vein, we argue that OFC research would benefit from a more balanced approach that also places focus on novel bottom-up investigations into OFC's computational capabilities. Furthermore, we believe that the knowledge gained by employing a more bottom-up approach to investigating OFC function will ultimately allow us to look at OFC's dysfunction in disease through a more nuanced biological lens. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Affiliation(s)
- Ege A Yalcinbas
- The Neurosciences Graduate Program, University of California, San Diego
| | - Christian Cazares
- The Neurosciences Graduate Program, University of California, San Diego
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19
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de Filippo R, Rost BR, Stumpf A, Cooper C, Tukker JJ, Harms C, Beed P, Schmitz D. Somatostatin interneurons activated by 5-HT 2A receptor suppress slow oscillations in medial entorhinal cortex. eLife 2021; 10:66960. [PMID: 33789079 PMCID: PMC8016478 DOI: 10.7554/elife.66960] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/10/2021] [Indexed: 12/31/2022] Open
Abstract
Serotonin (5-HT) is one of the major neuromodulators present in the mammalian brain and has been shown to play a role in multiple physiological processes. The mechanisms by which 5-HT modulates cortical network activity, however, are not yet fully understood. We investigated the effects of 5-HT on slow oscillations (SOs), a synchronized cortical network activity universally present across species. SOs are observed during anesthesia and are considered to be the default cortical activity pattern. We discovered that (±)3,4-methylenedioxymethamphetamine (MDMA) and fenfluramine, two potent 5-HT releasers, inhibit SOs within the entorhinal cortex (EC) in anesthetized mice. Combining opto- and pharmacogenetic manipulations with in vitro electrophysiological recordings, we uncovered that somatostatin-expressing (Sst) interneurons activated by the 5-HT2A receptor (5-HT2AR) play an important role in the suppression of SOs. Since 5-HT2AR signaling is involved in the etiology of different psychiatric disorders and mediates the psychological effects of many psychoactive serotonergic drugs, we propose that the newly discovered link between Sst interneurons and 5-HT will contribute to our understanding of these complex topics.
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Affiliation(s)
- Roberto de Filippo
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Cluster of Excellence NeuroCure, Berlin, Germany
| | - Benjamin R Rost
- German Centre for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Alexander Stumpf
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany
| | - Claire Cooper
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany
| | - John J Tukker
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany.,German Centre for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Christoph Harms
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Experimental Neurology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Center for Stroke Research Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Prateep Beed
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Cluster of Excellence NeuroCure, Berlin, Germany.,German Centre for Neurodegenerative Diseases (DZNE), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Einstein Center for Neurosciences Berlin, Berlin, Germany
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20
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Almog Y, Fadila S, Brusel M, Mavashov A, Anderson K, Rubinstein M. Developmental alterations in firing properties of hippocampal CA1 inhibitory and excitatory neurons in a mouse model of Dravet syndrome. Neurobiol Dis 2020; 148:105209. [PMID: 33271326 DOI: 10.1016/j.nbd.2020.105209] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/07/2020] [Accepted: 11/24/2020] [Indexed: 11/17/2022] Open
Abstract
Dravet syndrome (Dravet) is a rare, severe childhood-onset epilepsy, caused by heterozygous de novo mutations in the SCN1A gene, encoding for the alpha subunit of the voltage-gated sodium channel, NaV1.1. The neuronal basis of Dravet is debated, with evidence favoring reduced function of inhibitory neurons, that might be transient, or enhanced activity of excitatory cells. Here, we utilized Dravet mice to trace developmental changes in the hippocampal CA1 circuit, examining the properties of CA1 horizontal stratum-oriens (SO) interneurons and pyramidal neurons, through the pre-epileptic, severe and stabilization stages of Dravet. Our data indicate that reduced function of SO interneurons persists from the pre-epileptic through the stabilization stages, with the greatest functional impairment observed during the severe stage. In contrast, opposing changes were detected in CA1 excitatory neurons, with a transient increase in their excitability during the pre-epileptic stage, followed by reduced excitability at the severe stage. Interestingly, alterations in the function of both inhibitory and excitatory neurons were more pronounced when the firing was evoked by synaptic stimulation, implying that loss of function of NaV1.1 may also affect somatodendritic functions. These results suggest a complex pathophysiological mechanism and indicate that the developmental trajectory of this disease is governed by reciprocal functional changes in both excitatory and inhibitory neurons.
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Affiliation(s)
- Yael Almog
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; The Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Saja Fadila
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; The Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Marina Brusel
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Anat Mavashov
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Karen Anderson
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Moran Rubinstein
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; The Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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21
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Vann Jones SA, O’Kelly A. Psychedelics as a Treatment for Alzheimer's Disease Dementia. Front Synaptic Neurosci 2020; 12:34. [PMID: 32973482 PMCID: PMC7472664 DOI: 10.3389/fnsyn.2020.00034] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Currently, there are no disease-modifying treatments for Alzheimer's disease (AD) or any other dementia subtype. The renaissance in psychedelic research in recent years, in particular studies involving psilocybin and lysergic acid diethylamide (LSD), coupled with anecdotal reports of cognitive benefits from micro-dosing, suggests that they may have a therapeutic role in a range of psychiatric and neurological conditions due to their potential to stimulate neurogenesis, provoke neuroplastic changes and reduce neuroinflammation. This inevitably makes them interesting candidates for therapeutics in dementia. This mini-review will look at the basic science and current clinical evidence for the role of psychedelics in treating dementia, especially early AD, with a particular focus on micro-dosing of the classical psychedelics LSD and psilocybin.
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22
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Mechanisms underlying gain modulation in the cortex. Nat Rev Neurosci 2020; 21:80-92. [PMID: 31911627 DOI: 10.1038/s41583-019-0253-y] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2019] [Indexed: 01/19/2023]
Abstract
Cortical gain regulation allows neurons to respond adaptively to changing inputs. Neural gain is modulated by internal and external influences, including attentional and arousal states, motor activity and neuromodulatory input. These influences converge to a common set of mechanisms for gain modulation, including GABAergic inhibition, synaptically driven fluctuations in membrane potential, changes in cellular conductance and changes in other biophysical neural properties. Recent work has identified GABAergic interneurons as targets of neuromodulatory input and mediators of state-dependent gain modulation. Here, we review the engagement and effects of gain modulation in the cortex. We highlight key recent findings that link phenomenological observations of gain modulation to underlying cellular and circuit-level mechanisms. Finally, we place these cellular and circuit interactions in the larger context of their impact on perception and cognition.
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24
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Saitow F, Takumi T, Suzuki H. Change in serotonergic modulation contributes to the synaptic imbalance of neuronal circuit at the prefrontal cortex in the 15q11-13 duplication mouse model of autism. Neuropharmacology 2019; 165:107931. [PMID: 31901366 DOI: 10.1016/j.neuropharm.2019.107931] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/25/2019] [Accepted: 12/30/2019] [Indexed: 10/25/2022]
Abstract
The prefrontal cortex (PFC) has been extensively studied in autism spectrum disorder (ASD) in an attempt to understand the deficits in executive and other higher brain functions related to sociability and emotion. Disruption of the excitatory/inhibitory (E/I) balance of cortical circuits is thought to underlie the pathophysiology of ASD. Recently, we showed that 15q dup mice (a model for ASD with human chromosome 15q11-13 paternal duplication) exhibit disruption of the E/I balance in layer 2/3 pyramidal neurons of the somatosensory cortex due to a decrease in the number of inhibitory synapses. However, whether there is a pathological abnormality in E/I balance in the PFC of 15q dup mice remains unknown. In this study, we found that 15q dup facilitates the activity-induced LTP of glutamate synapses onto layer 5 pyramidal neurons by shifting the E/I balance to an excitatory state, which this was associated with differences in synaptic glutamatergic and GABAergic inputs onto GABAergic fast-spiking interneurons (FSINs). Furthermore, we found that FSIN excitability was well-modulated and regulated by the constitutive activation of 5-HT2 receptors in PFC microcircuits. These results provide new insights into the cellular mechanisms underlying maintenance of optimal E/I balance in the PFC.
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Affiliation(s)
- Fumihito Saitow
- Department of Pharmacology, Nippon Medical School, Tokyo, 113-8602, Japan.
| | - Toru Takumi
- RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Nippon Medical School, Tokyo, 113-8602, Japan
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25
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Sargin D, Jeoung HS, Goodfellow NM, Lambe EK. Serotonin Regulation of the Prefrontal Cortex: Cognitive Relevance and the Impact of Developmental Perturbation. ACS Chem Neurosci 2019; 10:3078-3093. [PMID: 31259523 DOI: 10.1021/acschemneuro.9b00073] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The prefrontal cortex is essential for both executive function and emotional regulation. The interrelationships among these behavioral domains are increasingly recognized, as well as their sensitivity to serotonin (5-hydroxytryptamine, 5-HT). Prefrontal cortex receives serotonergic inputs from the dorsal and median raphe nuclei and is modulated by multiple subtypes of 5-HT receptor across its layers and cell types. Extremes of serotonergic modulation alter mood regulation in vulnerable individuals, yet the impact of serotonin under more typical physiological parameters remains unclear. In this regard, new tools are permitting a closer examination of the behavioral impact of the serotonin system. Optogenetic and chemogenetic manipulations of dorsal raphe 5-HT neurons reveal that serotonin has a greater impact on executive function than previously appreciated. Domains that appear sensitive to fluctuations in 5-HT neuronal excitability include patience and cognitive flexibility. This work is broadly consistent with ex vivo research investigating how 5-HT regulates prefrontal cortex and its output projections. A growing literature suggests 5-HT modulation of these prefrontal circuits is unexpectedly flexible to alteration during development by genetic, behavioral, environmental or pharmacological manipulations, with lasting repercussions for cognition and emotional regulation. Here, we review the cellular and circuit mechanisms of prefrontal serotonergic modulation, investigate recent research into the cognitive consequences of the serotonergic system, and probe the lasting consequences of developmental perturbations. Understanding both the complexity of the prefrontal serotonin system and its sensitivity during development are essential to learn more about the vulnerabilities of this system in mood and anxiety disorders and the underappreciated cognitive consequences of these disorders and their treatment.
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Affiliation(s)
- Derya Sargin
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Physiology and Pharmacology, University of Calgary, Calgary AB T2N 1N4, Canada
| | - Ha-Seul Jeoung
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | | | - Evelyn K. Lambe
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of OBGYN, University of Toronto, Toronto, ON M5G 1E2, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada
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26
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Riedemann T. Diversity and Function of Somatostatin-Expressing Interneurons in the Cerebral Cortex. Int J Mol Sci 2019; 20:E2952. [PMID: 31212931 PMCID: PMC6627222 DOI: 10.3390/ijms20122952] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/08/2019] [Accepted: 06/14/2019] [Indexed: 02/01/2023] Open
Abstract
Inhibitory interneurons make up around 10-20% of the total neuron population in the cerebral cortex. A hallmark of inhibitory interneurons is their remarkable diversity in terms of morphology, synaptic connectivity, electrophysiological and neurochemical properties. It is generally understood that there are three distinct and non-overlapping interneuron classes in the mouse neocortex, namely, parvalbumin-expressing, 5-HT3A receptor-expressing and somatostatin-expressing interneuron classes. Each class is, in turn, composed of a multitude of subclasses, resulting in a growing number of interneuron classes and subclasses. In this review, I will focus on the diversity of somatostatin-expressing interneurons (SOM+ INs) in the cerebral cortex and elucidate their function in cortical circuits. I will then discuss pathological consequences of a malfunctioning of SOM+ INs in neurological disorders such as major depressive disorder, and present future avenues in SOM research and brain pathologies.
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Affiliation(s)
- Therese Riedemann
- Ludwig-Maximilians-University, Biomedical Center, Physiological Genomics, Großhaderner Str. 9, 82152 Planegg-Martinsried, Germany.
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27
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Burke KJ, Bender KJ. Modulation of Ion Channels in the Axon: Mechanisms and Function. Front Cell Neurosci 2019; 13:221. [PMID: 31156397 PMCID: PMC6533529 DOI: 10.3389/fncel.2019.00221] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022] Open
Abstract
The axon is responsible for integrating synaptic signals, generating action potentials (APs), propagating those APs to downstream synapses and converting them into patterns of neurotransmitter vesicle release. This process is mediated by a rich assortment of voltage-gated ion channels whose function can be affected on short and long time scales by activity. Moreover, neuromodulators control the activity of these proteins through G-protein coupled receptor signaling cascades. Here, we review cellular mechanisms and signaling pathways involved in axonal ion channel modulation and examine how changes to ion channel function affect AP initiation, AP propagation, and the release of neurotransmitter. We then examine how these mechanisms could modulate synaptic function by focusing on three key features of synaptic information transmission: synaptic strength, synaptic variability, and short-term plasticity. Viewing these cellular mechanisms of neuromodulation from a functional perspective may assist in extending these findings to theories of neural circuit function and its neuromodulation.
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Affiliation(s)
- Kenneth J Burke
- Neuroscience Graduate Program and Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Kevin J Bender
- Neuroscience Graduate Program and Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
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28
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Yu W, Yen YC, Lee YH, Tan S, Xiao Y, Lokman H, Ting AKT, Ganegala H, Kwon T, Ho WK, Je HS. Prenatal selective serotonin reuptake inhibitor (SSRI) exposure induces working memory and social recognition deficits by disrupting inhibitory synaptic networks in male mice. Mol Brain 2019; 12:29. [PMID: 30935412 PMCID: PMC6444596 DOI: 10.1186/s13041-019-0452-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/18/2019] [Indexed: 12/21/2022] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed antidepressant drugs in pregnant women. Infants born following prenatal exposure to SSRIs have a higher risk for behavioral abnormalities, however, the underlying mechanisms remains unknown. Therefore, we examined the effects of prenatal fluoxetine, the most commonly prescribed SSRI, in mice. Intriguingly, chronic in utero fluoxetine treatment impaired working memory and social novelty recognition in adult males. In the medial prefrontal cortex (mPFC), a key region regulating these behaviors, we found augmented spontaneous inhibitory synaptic transmission onto the layer 5 pyramidal neurons. Fast-spiking interneurons in mPFC exhibited enhanced intrinsic excitability and serotonin-induced excitability due to upregulated serotonin (5-HT) 2A receptor (5-HT2AR) signaling. More importantly, the behavioral deficits in prenatal fluoxetine treated mice were reversed by the application of a 5-HT2AR antagonist. Taken together, our findings suggest that alterations in inhibitory neuronal modulation are responsible for the behavioral alterations following prenatal exposure to SSRIs.
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Affiliation(s)
- Weonjin Yu
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore.,Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Yi-Chun Yen
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Young-Hwan Lee
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Shawn Tan
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Yixin Xiao
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore
| | - Hidayat Lokman
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Audrey Khoo Tze Ting
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Hasini Ganegala
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Taejoon Kwon
- Department of Biomedical Engineering, School of Life Science, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan, 44919, Republic of Korea
| | - Won-Kyung Ho
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.
| | - H Shawn Je
- Molecular Neurophysiology Laboratory, Signature Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore. .,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
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29
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Fleming E, Hull C. Serotonin regulates dynamics of cerebellar granule cell activity by modulating tonic inhibition. J Neurophysiol 2018; 121:105-114. [PMID: 30281395 DOI: 10.1152/jn.00492.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Understanding how afferent information is integrated by cortical structures requires identifying the factors shaping excitation and inhibition within their input layers. The input layer of the cerebellar cortex integrates diverse sensorimotor information to enable learned associations that refine the dynamics of movement. Specifically, mossy fiber afferents relay sensorimotor input into the cerebellum to excite granule cells, whose activity is regulated by inhibitory Golgi cells. To test how this integration can be modulated, we have used an acute brain slice preparation from young adult rats and found that encoding of mossy fiber input in the cerebellar granule cell layer can be regulated by serotonin (5-hydroxytryptamine, 5-HT) via a specific action on Golgi cells. We find that 5-HT depolarizes Golgi cells, likely by activating 5-HT2A receptors, but does not directly act on either granule cells or mossy fibers. As a result of Golgi cell depolarization, 5-HT significantly increases tonic inhibition onto both granule cells and Golgi cells. 5-HT-mediated Golgi cell depolarization is not sufficient, however, to alter the probability or timing of mossy fiber-evoked feed-forward inhibition onto granule cells. Together, increased granule cell tonic inhibition paired with normal feed-forward inhibition acts to reduce granule cell spike probability without altering spike timing. Hence, these data provide a circuit mechanism by which 5-HT can reduce granule cell activity without altering temporal representations of mossy fiber input. Such changes in network integration could enable flexible, state-specific suppression of cerebellar sensorimotor input that should not be learned or enable reversal learning for unwanted associations. NEW & NOTEWORTHY Serotonin (5-hydroxytryptamine, 5-HT) regulates synaptic integration at the input stage of cerebellar processing by increasing tonic inhibition of granule cells. This circuit mechanism reduces the probability of granule cell spiking without altering spike timing, thus suppressing cerebellar input without altering its temporal representation in the granule cell layer.
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Affiliation(s)
- Elizabeth Fleming
- Department of Neurobiology, Duke University Medical School , Durham, North Carolina
| | - Court Hull
- Department of Neurobiology, Duke University Medical School , Durham, North Carolina
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