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Király B, Domonkos A, Jelitai M, Lopes-Dos-Santos V, Martínez-Bellver S, Kocsis B, Schlingloff D, Joshi A, Salib M, Fiáth R, Barthó P, Ulbert I, Freund TF, Viney TJ, Dupret D, Varga V, Hangya B. The medial septum controls hippocampal supra-theta oscillations. Nat Commun 2023; 14:6159. [PMID: 37816713 PMCID: PMC10564782 DOI: 10.1038/s41467-023-41746-0] [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: 07/27/2022] [Accepted: 09/15/2023] [Indexed: 10/12/2023] Open
Abstract
Hippocampal theta oscillations orchestrate faster beta-to-gamma oscillations facilitating the segmentation of neural representations during navigation and episodic memory. Supra-theta rhythms of hippocampal CA1 are coordinated by local interactions as well as inputs from the entorhinal cortex (EC) and CA3 inputs. However, theta-nested gamma-band activity in the medial septum (MS) suggests that the MS may control supra-theta CA1 oscillations. To address this, we performed multi-electrode recordings of MS and CA1 activity in rodents and found that MS neuron firing showed strong phase-coupling to theta-nested supra-theta episodes and predicted changes in CA1 beta-to-gamma oscillations on a cycle-by-cycle basis. Unique coupling patterns of anatomically defined MS cell types suggested that indirect MS-to-CA1 pathways via the EC and CA3 mediate distinct CA1 gamma-band oscillations. Optogenetic activation of MS parvalbumin-expressing neurons elicited theta-nested beta-to-gamma oscillations in CA1. Thus, the MS orchestrates hippocampal network activity at multiple temporal scales to mediate memory encoding and retrieval.
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Affiliation(s)
- Bálint Király
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Department of Biological Physics, Institute of Physics, Eötvös Loránd University, Budapest, Hungary
| | - Andor Domonkos
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Márta Jelitai
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Vítor Lopes-Dos-Santos
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Sergio Martínez-Bellver
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Department of Anatomy and Human Embryology, Faculty of Medicine and Odontology, University of Valencia, Valencia, Spain
| | - Barnabás Kocsis
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Dániel Schlingloff
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Minas Salib
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Richárd Fiáth
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Péter Barthó
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - István Ulbert
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Tamás F Freund
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Tim J Viney
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - David Dupret
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Viktor Varga
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary.
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2
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Ursino M, Cesaretti N, Pirazzini G. A model of working memory for encoding multiple items and ordered sequences exploiting the theta-gamma code. Cogn Neurodyn 2022; 17:489-521. [PMID: 37007198 PMCID: PMC10050512 DOI: 10.1007/s11571-022-09836-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 02/25/2022] [Accepted: 05/27/2022] [Indexed: 11/24/2022] Open
Abstract
AbstractRecent experimental evidence suggests that oscillatory activity plays a pivotal role in the maintenance of information in working memory, both in rodents and humans. In particular, cross-frequency coupling between theta and gamma oscillations has been suggested as a core mechanism for multi-item memory. The aim of this work is to present an original neural network model, based on oscillating neural masses, to investigate mechanisms at the basis of working memory in different conditions. We show that this model, with different synapse values, can be used to address different problems, such as the reconstruction of an item from partial information, the maintenance of multiple items simultaneously in memory, without any sequential order, and the reconstruction of an ordered sequence starting from an initial cue. The model consists of four interconnected layers; synapses are trained using Hebbian and anti-Hebbian mechanisms, in order to synchronize features in the same items, and desynchronize features in different items. Simulations show that the trained network is able to desynchronize up to nine items without a fixed order using the gamma rhythm. Moreover, the network can replicate a sequence of items using a gamma rhythm nested inside a theta rhythm. The reduction in some parameters, mainly concerning the strength of GABAergic synapses, induce memory alterations which mimic neurological deficits. Finally, the network, isolated from the external environment (“imagination phase”) and stimulated with high uniform noise, can randomly recover sequences previously learned, and link them together by exploiting the similarity among items.
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Affiliation(s)
- Mauro Ursino
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Campus of Cesena Area di Campus Cesena Via Dell’Università 50, 47521 Cesena, FC Italy
| | - Nicole Cesaretti
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Campus of Cesena Area di Campus Cesena Via Dell’Università 50, 47521 Cesena, FC Italy
| | - Gabriele Pirazzini
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Campus of Cesena Area di Campus Cesena Via Dell’Università 50, 47521 Cesena, FC Italy
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3
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The Role of the Posterior Hypothalamus in the Modulation and Production of Rhythmic Theta Oscillations. Neuroscience 2021; 470:100-115. [PMID: 34271089 DOI: 10.1016/j.neuroscience.2021.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/18/2021] [Accepted: 07/05/2021] [Indexed: 11/24/2022]
Abstract
Theta rhythm recorded as an extracellular synchronous field potential is generated in a number of brain sites including the hippocampus. The physiological occurrence of hippocampal theta rhythm is associated with the activation of a number of structures forming the ascending brainstem-hippocampal synchronizing pathway. Experimental evidence indicates that the supramammillary nucleus and posterior hypothalamic nuclei, considered as the posterior hypothalamic area, comprise a critical node of this ascending pathway. The posterior hypothalamic area plays an important role in movement control, place-learning, memory processing, emotion and arousal. In the light of multiplicity of functions of the posterior hypothalamic area and the influence of theta field oscillations on a number of neural processes, it is the authors' intent to summarize the data concerning the involvement of the supramammillary nucleus and posterior hypothalamic nuclei in the modulation of limbic theta rhythmicity as well as the ability of these brain structures to independently generate theta rhythmicity.
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4
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Staszelis A, Kowalczyk T. The role of the posterior hypothalamic area
in the generation of theta rhythm. POSTEP HIG MED DOSW 2021. [DOI: 10.5604/01.3001.0014.9333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Theta rhythm is one of the best synchronized patterns of the oscillatory activity recorded in
the mammalian brain. In humans, this rhythm is associated with REM sleep, spatial navigation,
memory functions, analytical and language processes. On the other hand, it can be treated as
a non-specific marker of such pathological states of the central nervous system as Alzheimer’s
disease or epilepsy. The hippocampal formation is the key structure involved in the generation
of this bioelectric phenomenon, both in humans and rodents (the most commonly studied laboratory
animals). Theta rhythm appearance in the hippocampus is dependent on the interaction
of multiple different structures of the nervous system. One of them is the posterior hypothalamic
area (PHa), which constitutes a crucial part of the neuronal system modulating the ability
of the hippocampal formation to generate theta rhythm. Although the research results encompassed
in this paper emphasize the essential role of the PHa as a modulator of the hippocampal
theta rhythm, it was the authors’ intent to indicate that this area is also capable of generating
local rhythmical theta oscillations, independently of the influence of other brain structures.
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Affiliation(s)
- Agata Staszelis
- Katedra Neurobiologii, Wydział Biologii i Ochrony Środowiska, Uniwersytet Łódzki, Łódź
| | - Tomasz Kowalczyk
- Katedra Neurobiologii, Wydział Biologii i Ochrony Środowiska, Uniwersytet Łódzki, Łódź
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5
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Ibrahim KM, Ariffin MZ, Khanna S. Modulation of Septo-Hippocampal Neural Responses in Anesthetized and Behaving Rats by Septal AMPA Receptor Mechanisms. Front Neural Circuits 2021; 15:663633. [PMID: 34177470 PMCID: PMC8220821 DOI: 10.3389/fncir.2021.663633] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/06/2021] [Indexed: 01/14/2023] Open
Abstract
This study explored the effects of septal glutamatergic transmission on septal-hippocampal theta activity via intraseptal microinjection of antagonist at AMPA receptors (AMPAR). The current results showed that microinjection of AMPAR antagonist, NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione, 20 μg/μl, 0.5 μl), evoked a decrease in the frequency of theta activity evoked by various means in anesthetized and behaving rat. Theta wave activity was induced on: (a) intraseptal microinjection of carbachol, an agonist at cholinergic receptors, (b) reticular stimulation, (c) exploration in novel open field (OF), and (d) hind paw (HP) injection of the algogen, formalin. The effect on frequency in the formalin test was observed in an early period on injection of formalin, which was novel to the animal, but not in the later more sustained phase of the formalin test. The effect of NBQX, being seen in both anesthetized and behaving animals, suggests that the modulation of theta wave frequency, including in novelty, is a function of AMPAR in MS. The effect of the antagonist on theta power was less apparent, being observed only in anesthetized animals. In addition to theta power and frequency, intraseptal NBQX also attenuated suppression of CA1 population spike (PS) induced by intraseptal carbachol, thus suggesting that septal glutamate neurotransmission is involved in the spectrum of MS-mediated network responses. Indeed, in the context of behavior, formalin injection induced an increase in the level of septal glutamate, while NBQX attenuated nociceptive behaviors. Notably, MS is involved in the modulation of formalin nociception. These findings suggest that AMPA receptors are a key modulator of septal physiological function.
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Affiliation(s)
- Khairunisa Mohamad Ibrahim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Mohammed Zacky Ariffin
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Sanjay Khanna
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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6
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Billwiller F, Castillo L, Elseedy H, Ivanov AI, Scapula J, Ghestem A, Carponcy J, Libourel PA, Bras H, Abdelmeguid NE, Krook-Magnuson E, Soltesz I, Bernard C, Luppi PH, Esclapez M. GABA-glutamate supramammillary neurons control theta and gamma oscillations in the dentate gyrus during paradoxical (REM) sleep. Brain Struct Funct 2020; 225:2643-2668. [PMID: 32970253 PMCID: PMC7674372 DOI: 10.1007/s00429-020-02146-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 09/08/2020] [Indexed: 12/25/2022]
Abstract
Several studies suggest that neurons from the lateral region of the SuM (SuML) innervating the dorsal dentate gyrus (DG) display a dual GABAergic and glutamatergic transmission and are specifically activated during paradoxical (REM) sleep (PS). The objective of the present study is to characterize the anatomical, neurochemical and electrophysiological properties of the SuML-DG projection neurons and to determine how they control DG oscillations and neuronal activation during PS and other vigilance states. For this purpose, we combine structural connectivity techniques using neurotropic viral vectors (rabies virus, AAV), neurochemical anatomy (immunohistochemistry, in situ hybridization) and imaging (light, electron and confocal microscopy) with in vitro (patch clamp) and in vivo (LFP, EEG) optogenetic and electrophysiological recordings performed in transgenic VGLUT2-cre male mice. At the cellular level, we show that the SuML-DG neurons co-release GABA and glutamate on dentate granule cells and increase the activity of a subset of DG granule cells. At the network level, we show that activation of the SuML-DG pathway increases theta power and frequency during PS as well as gamma power during PS and waking in the DG. At the behavioral level, we show that the activation of this pathway does not change animal behavior during PS, induces awakening during slow wave sleep and increases motor activity during waking. These results suggest that the SuML-DG pathway is capable of supporting the increase of theta and gamma power in the DG observed during PS and plays an important modulatory role of DG network activity during this state.
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Affiliation(s)
- Francesca Billwiller
- UMR 5292 CNRS/U1028 INSERM, Centre hospitalier le vinatier, Neurocampus, University Lyon I, Bron, France
| | - Laura Castillo
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France
| | - Heba Elseedy
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France
- Zoology Department, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Anton Ivanovich Ivanov
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France
| | - Jennyfer Scapula
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France
| | - Antoine Ghestem
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France
| | - Julien Carponcy
- UMR 5292 CNRS/U1028 INSERM, Centre hospitalier le vinatier, Neurocampus, University Lyon I, Bron, France
| | - Paul Antoine Libourel
- UMR 5292 CNRS/U1028 INSERM, Centre hospitalier le vinatier, Neurocampus, University Lyon I, Bron, France
| | - Hélène Bras
- CNRS, INT, Institut de Neurosciences Timone, Aix-Marseille Univ, Marseille, France
| | | | | | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, USA
| | - Christophe Bernard
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France
| | - Pierre-Hervé Luppi
- UMR 5292 CNRS/U1028 INSERM, Centre hospitalier le vinatier, Neurocampus, University Lyon I, Bron, France
| | - Monique Esclapez
- INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille Univ, Marseille, France.
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7
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Liu CY, Tsai CJ, Yasugaki S, Nagata N, Morita M, Isotani A, Yanagisawa M, Hayashi Y. Copine-7 is required for REM sleep regulation following cage change or water immersion and restraint stress in mice. Neurosci Res 2020; 165:14-25. [PMID: 32283105 DOI: 10.1016/j.neures.2020.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 10/24/2022]
Abstract
Sleep is affected by the environment. In rodents, changes in the amount of rapid eye movement sleep (REMS) can precede those of other sleep/wake stages. The molecular mechanism underlying the dynamic regulation of REMS remains poorly understood. Here, we focused on the sublaterodorsal nucleus (SLD), located in the pontine tegmental area, which plays a crucial role in the regulation of REMS. We searched for genes selectively expressed in the SLD and identified copine-7 (Cpne7), whose involvement in sleep was totally unknown. We generated Cpne7-Cre knock-in mice, which enabled both the knockout (KO) of Cpne7 and the genetic labeling of Cpne7-expressing cells. While Cpne7-KO mice exhibited normal sleep under basal conditions, the amount of REMS in Cpne7-KO mice was larger compared to wildtype mice following cage change or water immersion and restraint stress, both of which are conditions that acutely reduce REMS. Thus, it was suggested that copine-7 is involved in negatively regulating REMS under certain conditions. In addition, chemogenetically activating Cpne7-expressing neurons in the SLD reduced the amount of REMS, suggesting that these neurons negatively regulate REMS. These results identify copine-7 and Cpne7-expressing neurons in the SLD as candidate molecular or neuronal components of the regulatory system that controls REMS.
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Affiliation(s)
- Chih-Yao Liu
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Chia-Jung Tsai
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Shinnosuke Yasugaki
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Nanae Nagata
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Miho Morita
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Ayako Isotani
- NPO for Biotechnology Research and Development, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Department of Molecular Genetics, University of Texas Southwestern Medical Center, 75390, Dallas, TX, USA; Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; R&D Center for Frontiers of MIRAI in Policy and Technology (F-MIRAI), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Yu Hayashi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
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8
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Sil’kis IG. Possible Mechanisms of the Complex Effects of Acetylcholine on Theta Activity, Learning, and Memory. NEUROCHEM J+ 2019. [DOI: 10.1134/s1819712419020119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Unal G, Crump MG, Viney TJ, Éltes T, Katona L, Klausberger T, Somogyi P. Spatio-temporal specialization of GABAergic septo-hippocampal neurons for rhythmic network activity. Brain Struct Funct 2018; 223:2409-2432. [PMID: 29500537 PMCID: PMC5968071 DOI: 10.1007/s00429-018-1626-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 02/10/2018] [Indexed: 01/06/2023]
Abstract
Medial septal GABAergic neurons of the basal forebrain innervate the hippocampus and related cortical areas, contributing to the coordination of network activity, such as theta oscillations and sharp wave-ripple events, via a preferential innervation of GABAergic interneurons. Individual medial septal neurons display diverse activity patterns, which may be related to their termination in different cortical areas and/or to the different types of innervated interneurons. To test these hypotheses, we extracellularly recorded and juxtacellularly labeled single medial septal neurons in anesthetized rats in vivo during hippocampal theta and ripple oscillations, traced their axons to distant cortical target areas, and analyzed their postsynaptic interneurons. Medial septal GABAergic neurons exhibiting different hippocampal theta phase preferences and/or sharp wave-ripple related activity terminated in restricted hippocampal regions, and selectively targeted a limited number of interneuron types, as established on the basis of molecular markers. We demonstrate the preferential innervation of bistratified cells in CA1 and of basket cells in CA3 by individual axons. One group of septal neurons was suppressed during sharp wave-ripples, maintained their firing rate across theta and non-theta network states and mainly fired along the descending phase of CA1 theta oscillations. In contrast, neurons that were active during sharp wave-ripples increased their firing significantly during "theta" compared to "non-theta" states, with most firing during the ascending phase of theta oscillations. These results demonstrate that specialized septal GABAergic neurons contribute to the coordination of network activity through parallel, target area- and cell type-selective projections to the hippocampus.
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Affiliation(s)
- Gunes Unal
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK.
- Department of Psychology, Bogazici University, 34342, Istanbul, Turkey.
| | - Michael G Crump
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Tim J Viney
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Tímea Éltes
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, Hungary
| | - Linda Katona
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Thomas Klausberger
- Center for Brain Research, Medical University of Vienna, 1090, Vienna, Austria
| | - Peter Somogyi
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK.
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, Hungary.
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10
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Hu M, Li W, Liang H. A Copula-Based Granger Causality Measure for the Analysis of Neural Spike Train Data. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2018; 15:562-569. [PMID: 29610104 DOI: 10.1109/tcbb.2014.2388311] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In systems neuroscience, it is becoming increasingly common to record the activity of hundreds of neurons simultaneously via electrode arrays. The ability to accurately measure the causal interactions among multiple neurons in the brain is crucial to understanding how neurons work in concert to generate specific brain functions. The development of new statistical methods for assessing causal influence between spike trains is still an active field of neuroscience research. Here, we suggest a copula-based Granger causality measure for the analysis of neural spike train data. This method is built upon our recent work on copula Granger causality for the analysis of continuous-valued time series by extending it to point-process neural spike train data. The proposed method is therefore able to reveal nonlinear and high-order causality in the spike trains while retaining all the computational advantages such as model-free, efficient estimation, and variability assessment of Granger causality. The performance of our algorithm can be further boosted with time-reversed data. Our method performed well on extensive simulations, and was then demonstrated on neural activity simultaneously recorded from primary visual cortex of a monkey performing a contour detection task.
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11
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Kocsis B, Pittman-Polletta BR, Roy A. Respiration-coupled rhythms in prefrontal cortex: beyond if, to when, how, and why. Brain Struct Funct 2018; 223:11-16. [PMID: 29222723 PMCID: PMC5794025 DOI: 10.1007/s00429-017-1587-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 12/02/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Bernat Kocsis
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | | | - Alexis Roy
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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12
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Kang D, Ding M, Topchiy I, Kocsis B. Reciprocal Interactions between Medial Septum and Hippocampus in Theta Generation: Granger Causality Decomposition of Mixed Spike-Field Recordings. Front Neuroanat 2017; 11:120. [PMID: 29311851 PMCID: PMC5733038 DOI: 10.3389/fnana.2017.00120] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/27/2017] [Indexed: 11/25/2022] Open
Abstract
The medial septum (MS) plays an essential role in rhythmogenesis in the hippocampus (HIPP); theta-rhythmic bursts of MS neurons are believed to drive theta oscillations in rats’ HIPP. The MS theta pacemaker hypothesis has solid foundation but the MS-hippocampal interactions during different behavioral states are poorly understood. The MS and the HIPP have reciprocal connections and it is not clear in particular what role, if any, the strong HIPP to MS projection plays in theta generation. To study the functional interactions between MS and HIPP during different behavioral states, this study investigated the relationship between MS single-unit activity and HIPP field potential oscillations during theta states of active waking and REM sleep and non-theta states of slow wave sleep (SWS) and quiet waking (QW), i.e., sleep-wake states that comprise the full behavioral repertoire of undisturbed, freely moving rats. We used non-parametric Granger causality (GC) to decompose the MS-HIPP synchrony into its directional components, MS→HIPP and HIPP→MS, and to examine the causal interactions between them within the theta frequency band. We found a significant unidirectional MS→HIPP influence in non-theta states which switches to bidirectional theta drive during theta states with MS→HIPP and HIPP→MS GC being of equal magnitude. In non-theta states, unidirectional MS→HIPP influence was accompanied by significant MS-HIPP coherence, but no signs of theta oscillations in the HIPP. In theta states of active waking and REM sleep, sharp theta coherence and strong theta power in both structures was associated with a rise in HIPP→MS to the level of the MS→HIPP drive. Thus, striking differences between waking and REM sleep theta states and non-theta states of SWS and QW were primarily observed in activation of theta influence carried by the descending HIPP→MS pathway associated with more regular rhythmic bursts in the MS and sharper MS→HIPP GC spectra without a significant increase in MS→HIPP GC magnitude. The results of this study suggest an essential role of descending HIPP to MS projections in theta generation.
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Affiliation(s)
- Daesung Kang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Mingzhou Ding
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Irina Topchiy
- Department of Psychiatry, Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School, Harvard University, Boston, MA, United States
| | - Bernat Kocsis
- Department of Psychiatry, Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School, Harvard University, Boston, MA, United States
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13
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Tsanov M. Differential and complementary roles of medial and lateral septum in the orchestration of limbic oscillations and signal integration. Eur J Neurosci 2017; 48:2783-2794. [DOI: 10.1111/ejn.13746] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Marian Tsanov
- Trinity College Institute of Neuroscience; Trinity College Dublin; Dublin 2 Ireland
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14
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Young CK, Ruan M, McNaughton N. A Critical Assessment of Directed Connectivity Estimates with Artificially Imposed Causality in the Supramammillary-Septo-Hippocampal Circuit. Front Syst Neurosci 2017; 11:72. [PMID: 29033799 PMCID: PMC5627232 DOI: 10.3389/fnsys.2017.00072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 09/19/2017] [Indexed: 11/23/2022] Open
Abstract
Algorithms for estimating directed connectivity have become indispensable to further understand the neurodynamics between functionally coupled brain areas. The evaluation of directed connectivity on the propagation of brain activity has largely been based on simulated data or toy models, where various hidden properties of neurophysiological data may not be fully recapitulated. In this study, directionality was unequivocally manipulated in the freely moving rat in a unique dataset, where normal oscillatory interactions between the supramammillary nucleus (SuM) and hippocampus (HPC) were attenuated by temporary medial septal (MS) inactivation, and replaced by electrical stimulation of the fornix to evaluate the performance of several directed connectivity assessment methods. The directed transfer function, partial directed coherence, directed coherence, pair-wise Geweke-Granger causality, phase slope index, and phase transfer entropy, all found SuM to HPC theta propagation when the MS is inactivated, and HPC activity was driven by peaks of simultaneously recorded SuM theta. As expected from theoretical expectations and simulated data, signal features including coupling strength, signal-to-noise ratio, and stationarity all weakly affected directed connectivity measures. We conclude that all the examined directed connectivity estimates correctly identify artificially imposed uni-directionality of brain oscillations in freely moving animals. Non-auto-regressive modeling based methods appear to be the most robust, and are least affected by inherent features in data such as signal-to-noise ratio and stationarity.
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Affiliation(s)
- Calvin K Young
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Ming Ruan
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,Wuhan Asia Heart Hospital, Wuhan, China
| | - Neil McNaughton
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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15
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Ariffin MZ, Low CM, Khanna S. Medial Septum Modulates Cellular Response Induced in Hippocampus on Microinjection of Cholinergic Agonists into Hypothalamic Lateral Supramammillary Nucleus. Front Neuroanat 2017; 11:79. [PMID: 28966579 PMCID: PMC5605574 DOI: 10.3389/fnana.2017.00079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/31/2017] [Indexed: 11/13/2022] Open
Abstract
Cholinergic mechanisms in supramammillary nucleus (SuM), especially the lateral SuM (lSuM) modulates septo-hippocampal neural activity. The lSuM, as compared to the contiguous medial SuM (mSuM) has relatively dense projections to hippocampus and cingulate cortex (Cg). In the present study, we have investigated whether the effects of cholinergic activation of SuM on hippocampal and cortical neural activities involve a cooperative interaction with the medial septum (MS). Microinjection of the broad-spectrum cholinergic agonist, carbachol, or the cholinergic-nicotinic receptor agonist, nicotine, into the lSuM and the mSuM in urethane anesthetized rat evoked a similar pattern of hippocampal theta rhythm. Despite that, only the lSuM microinjections resulted in an increase in expression of c-Fos-like immunoreactivity (c-Fos-ir) in neurons, including interneurons, of the ipsilateral hippocampus with a very dense expression in dentate gyrus. Likewise, a robust induction of c-Fos-ir was also observed in the ipsilateral Cg. Inhibition of the MS with muscimol pre-treatment attenuated both carbachol-evoked c-Fos-ir and theta activation. The findings indicate that cholinergic–nicotinic mechanisms in lSuM evoke not only neural activation via the ascending synchronizing pathway but also an MS-modulated expression of the plasticity-related molecule c-Fos in cortical regions that are strongly innervated by the lSuM.
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Affiliation(s)
- Mohammed Z Ariffin
- Department of Physiology, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore
| | - Chian-Ming Low
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore.,Department of Anesthesia, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore
| | - Sanjay Khanna
- Department of Physiology, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore.,Neurobiology Program, Life Science Institute, National University of SingaporeSingapore, Singapore
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16
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Ruan M, Young CK, McNaughton N. Bi-Directional Theta Modulation between the Septo-Hippocampal System and the Mammillary Area in Free-Moving Rats. Front Neural Circuits 2017; 11:62. [PMID: 28955209 PMCID: PMC5600904 DOI: 10.3389/fncir.2017.00062] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 08/25/2017] [Indexed: 01/07/2023] Open
Abstract
Hippocampal (HPC) theta oscillations have long been linked to various functions of the brain. Many cortical and subcortical areas that also exhibit theta oscillations have been linked to functional circuits with the hippocampus on the basis of coupled activities at theta frequencies. We examine, in freely moving rats, the characteristics of diencephalic theta local field potentials (LFPs) recorded in the supramammillary/mammillary (SuM/MM) areas that are bi-directionally connected to the HPC through the septal complex. Using partial directed coherence (PDC), we find support for previous suggestions that SuM modulates HPC theta at higher frequencies. We find weak separation of SuM and MM by dominant theta frequency recorded locally. Contrary to oscillatory cell activities under anesthesia where SuM is insensitive, but MM is sensitive to medial septal (MS) inactivation, theta LFPs persisted and became indistinguishable after MS-inactivation. However, MS-inactivation attenuated SuM/MM theta power, while increasing the frequency of SuM/MM theta. MS-inactivation also reduced root mean squared power in both HPC and SuM/MM equally, but reduced theta power differentially in the time domain. We provide converging evidence that SuM is preferentially involved in coding HPC theta at higher frequencies, and that the MS-HPC circuit normally imposes a frequency-limiting modulation over the SuM/MM area as suggested by cell-based recordings in anesthetized animals. In addition, we provide evidence that the postulated SuM-MS-HPC-MM circuit is under complex bi-directional control, rather than SuM and MM having roles as unidirectional relays in the network.
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Affiliation(s)
- Ming Ruan
- Department of Psychology and Brain Health Research Centre, University of OtagoDunedin, New Zealand.,Department of Pediatrics and Neonatal Services, Zhuhai Municipal Women's and Children's HospitalGuangdong, China
| | - Calvin K Young
- Department of Psychology and Brain Health Research Centre, University of OtagoDunedin, New Zealand
| | - Neil McNaughton
- Department of Psychology and Brain Health Research Centre, University of OtagoDunedin, New Zealand
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17
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Gutiérrez-Guzmán BE, Hernández-Pérez JJ, Olvera-Cortés ME. Serotonergic modulation of septo-hippocampal and septo-mammillary theta activity during spatial learning, in the rat. Behav Brain Res 2017; 319:73-86. [DOI: 10.1016/j.bbr.2016.11.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/08/2016] [Accepted: 11/08/2016] [Indexed: 11/16/2022]
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18
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Kaminski M, Brzezicka A, Kaminski J, Blinowska KJ. Measures of Coupling between Neural Populations Based on Granger Causality Principle. Front Comput Neurosci 2016; 10:114. [PMID: 27833546 PMCID: PMC5080292 DOI: 10.3389/fncom.2016.00114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 10/12/2016] [Indexed: 12/18/2022] Open
Abstract
This paper shortly reviews the measures used to estimate neural synchronization in experimental settings. Our focus is on multivariate measures of dependence based on the Granger causality (G-causality) principle, their applications and performance in respect of robustness to noise, volume conduction, common driving, and presence of a “weak node.” Application of G-causality measures to EEG, intracranial signals and fMRI time series is addressed. G-causality based measures defined in the frequency domain allow the synchronization between neural populations and the directed propagation of their electrical activity to be determined. The time-varying G-causality based measure Short-time Directed Transfer Function (SDTF) supplies information on the dynamics of synchronization and the organization of neural networks. Inspection of effective connectivity patterns indicates a modular structure of neural networks, with a stronger coupling within modules than between them. The hypothetical plausible mechanism of information processing, suggested by the identified synchronization patterns, is communication between tightly coupled modules intermitted by sparser interactions providing synchronization of distant structures.
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Affiliation(s)
- Maciej Kaminski
- Department of Biomedical Physics, Faculty of Physics, University of Warsaw Warsaw, Poland
| | - Aneta Brzezicka
- Department of Psychology, University of Social Sciences and Humanities Warsaw, Poland
| | - Jan Kaminski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University Torun, Poland
| | - Katarzyna J Blinowska
- Department of Biomedical Physics, Faculty of Physics, University of WarsawWarsaw, Poland; Institute of Biocybernetics and Biomedical Engineering of Polish Academy of SciencesWarsaw, Poland
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19
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Matsumoto N, Okamoto K, Takagi Y, Ikegaya Y. 3-Hz subthreshold oscillations of CA2 neurons In vivo. Hippocampus 2016; 26:1570-1578. [PMID: 27650674 DOI: 10.1002/hipo.22657] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2016] [Indexed: 12/12/2022]
Abstract
The CA2 region is unique in the hippocampus; it receives direct synaptic innervations from several hypothalamic nuclei and expresses various receptors of neuromodulators, including adenosine, vasopressin, and oxytocin. Furthermore, the CA2 region may have distinct brain functions, such as the control of instinctive and social behaviors; however, little is known about the dynamics of the subthreshold membrane potentials of CA2 neurons in vivo. We conducted whole-cell current-clamp recordings from CA2 pyramidal cells in urethane-anesthetized mice and monitored the intrinsic fluctuations in their membrane potentials. The CA2 pyramidal cells emitted spontaneous action potentials at mean firing rates of ∼0.8 Hz. In approximately half of the neurons, the subthreshold membrane potential oscillated at ∼3 Hz. In two neurons, we obtained simultaneous recordings of local field potentials from the CA1 stratum radiatum and demonstrated that the 3-Hz oscillations of CA2 neurons were not correlated with CA1 field potentials. In tetrodotoxin-perfused acute hippocampal slices, the membrane potentials of CA2 pyramidal cells were not preferentially entrained to 3-Hz sinusoidal current inputs, which suggest that intracellular 3-Hz oscillations reflect the neuronal dynamics of the surrounding networks. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Nobuyoshi Matsumoto
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kazuki Okamoto
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yuki Takagi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka, Japan
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20
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Fuller PM, Gooley JJ, Saper CB. Neurobiology of the Sleep-Wake Cycle: Sleep Architecture, Circadian Regulation, and Regulatory Feedback. J Biol Rhythms 2016; 21:482-93. [PMID: 17107938 DOI: 10.1177/0748730406294627] [Citation(s) in RCA: 304] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This mini-review article presents the remarkable progress that has been made in the past decade in our understanding of the neural circuitry underlying the regulation of sleep-wake states and circadian control of behaviors. Following a brief introduction to sleep architecture and physiology, the authors describe the neural circuitry and neurotransmitters that regulate sleep and cortical arousal (i.e., wakefulness). They next examine how sleep and wakefulness are regulated by mutual inhibition between sleep-and arousal-promoting circuitry and how this interaction functions analogously to an electronic “flip-flop” switch that ensures behavioral state stability. The authors then discuss the role of circadian and homeostatic processes in the consolidation of sleep, including the physiologic basis of homeostatic sleep drive (i.e., wake-dependent increase in sleep propensity) and the role of the SCN in the circadian regulation of sleep-wake cycles. Finally, they describe the hypothalamic circuitry for the integration of photic and nonphotic environmental time cues and how this integration allows organisms to sculpt patterns of rest-activity and sleep-wake cycles that are optimally adaptive.
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Affiliation(s)
- Patrick M Fuller
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Room 814, 77 Louis Pasteur Avenue, Boston, MA 02115, USA
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21
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Liu S, Molenaar P. Testing for Granger Causality in the Frequency Domain: A Phase Resampling Method. MULTIVARIATE BEHAVIORAL RESEARCH 2016; 51:53-66. [PMID: 26881957 DOI: 10.1080/00273171.2015.1100528] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This article introduces phase resampling, an existing but rarely used surrogate data method for making statistical inferences of Granger causality in frequency domain time series analysis. Granger causality testing is essential for establishing causal relations among variables in multivariate dynamic processes. However, testing for Granger causality in the frequency domain is challenging due to the nonlinear relation between frequency domain measures (e.g., partial directed coherence, generalized partial directed coherence) and time domain data. Through a simulation study, we demonstrate that phase resampling is a general and robust method for making statistical inferences even with short time series. With Gaussian data, phase resampling yields satisfactory type I and type II error rates in all but one condition we examine: when a small effect size is combined with an insufficient number of data points. Violations of normality lead to slightly higher error rates but are mostly within acceptable ranges. We illustrate the utility of phase resampling with two empirical examples involving multivariate electroencephalography (EEG) and skin conductance data.
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Affiliation(s)
- Siwei Liu
- a Human Development and Family Studies , Department of Human Ecology , University of California , Davis
| | - Peter Molenaar
- b Department of Human Development and Family Studies , The Pennsylvania State University
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22
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Hernández-Pérez JJ, Gutiérrez-Guzmán BE, López-Vázquez MÁ, Olvera-Cortés ME. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze. Front Pharmacol 2015; 6:250. [PMID: 26578960 PMCID: PMC4625187 DOI: 10.3389/fphar.2015.00250] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/14/2015] [Indexed: 11/29/2022] Open
Abstract
Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in support of a role for serotonin as a modulator of hippocampal learning, acting through changes in the synchronicity evoked in several relays of the SAS.
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Affiliation(s)
- J. Jesús Hernández-Pérez
- Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro SocialMorelia, México
| | - Blanca E. Gutiérrez-Guzmán
- Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro SocialMorelia, México
| | - Miguel Á. López-Vázquez
- Laboratorio de Neuroplasticidad de los Procesos Cognitivos, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro SocialMorelia, México
- Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de HidalgoMorelia, México
| | - María E. Olvera-Cortés
- Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro SocialMorelia, México
- *Correspondence: María E. Olvera-Cortés
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23
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Kang D, Ding M, Topchiy I, Shifflett L, Kocsis B. Theta-rhythmic drive between medial septum and hippocampus in slow-wave sleep and microarousal: a Granger causality analysis. J Neurophysiol 2015; 114:2797-803. [PMID: 26354315 DOI: 10.1152/jn.00542.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/03/2015] [Indexed: 11/22/2022] Open
Abstract
Medial septum (MS) plays a critical role in controlling the electrical activity of the hippocampus (HIPP). In particular, theta-rhythmic burst firing of MS neurons is thought to drive lasting HIPP theta oscillations in rats during waking motor activity and REM sleep. Less is known about MS-HIPP interactions in nontheta states such as non-REM sleep, in which HIPP theta oscillations are absent but theta-rhythmic burst firing in subsets of MS neurons is preserved. The present study used Granger causality (GC) to examine the interaction patterns between MS and HIPP in slow-wave sleep (SWS, a nontheta state) and during its short interruptions called microarousals (a transient theta state). We found that during SWS, while GC revealed a unidirectional MS→HIPP influence over a wide frequency band (2-12 Hz, maximum: ∼8 Hz), there was no theta peak in the hippocampal power spectra, indicating a lack of theta activity in HIPP. In contrast, during microarousals, theta peaks were seen in both MS and HIPP power spectra and were accompanied by bidirectional GC with MS→HIPP and HIPP→MS theta drives being of equal magnitude. Thus GC in a nontheta state (SWS) vs. a theta state (microarousal) primarily differed in the level of HIPP→MS. The present findings suggest a modification of our understanding of the role of MS as the theta generator in two regards. First, a MS→HIPP theta drive does not necessarily induce theta field oscillations in the hippocampus, as found in SWS. Second, HIPP theta oscillations entail bidirectional theta-rhythmic interactions between MS and HIPP.
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Affiliation(s)
- D Kang
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida; and
| | - M Ding
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida; and
| | - I Topchiy
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - L Shifflett
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - B Kocsis
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
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24
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Modeling synchronous theta activity in the medial septum: key role of local communications between different cell populations. J Comput Neurosci 2015; 39:1-16. [DOI: 10.1007/s10827-015-0564-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 11/25/2022]
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25
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Astasheva E, Astashev M, Kitchigina V. Changes in the behavior and oscillatory activity in cortical and subcortical brain structures induced by repeated l-glutamate injections to the medial septal area in guinea pigs. Epilepsy Res 2015; 109:134-45. [DOI: 10.1016/j.eplepsyres.2014.10.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/14/2014] [Accepted: 10/28/2014] [Indexed: 11/25/2022]
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26
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Soussi R, Boulland JL, Bassot E, Bras H, Coulon P, Chaudhry FA, Storm-Mathisen J, Ferhat L, Esclapez M. Reorganization of supramammillary-hippocampal pathways in the rat pilocarpine model of temporal lobe epilepsy: evidence for axon terminal sprouting. Brain Struct Funct 2014; 220:2449-68. [PMID: 24889162 PMCID: PMC4481331 DOI: 10.1007/s00429-014-0800-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/14/2014] [Indexed: 01/11/2023]
Abstract
In mesial temporal lobe epilepsy (MTLE), spontaneous seizures likely originate from a multi-structural epileptogenic zone, including several regions of the limbic system connected to the hippocampal formation. In this study, we investigate the structural connectivity between the supramammillary nucleus (SuM) and the dentate gyrus (DG) in the model of MTLE induced by pilocarpine in the rat. This hypothalamic nucleus, which provides major extracortical projections to the hippocampal formation, plays a key role in the regulation of several hippocampus-dependent activities, including theta rhythms, memory function and emotional behavior, such as stress and anxiety, functions that are known to be altered in MTLE. Our findings demonstrate a marked reorganization of DG afferents originating from the SuM in pilocarpine-treated rats. This reorganization, which starts during the latent period, is massive when animals become epileptic and continue to evolve during epilepsy. It is characterized by an aberrant distribution and an increased number of axon terminals from neurons of both lateral and medial regions of the SuM, invading the entire inner molecular layer of the DG. This reorganization, which reflects an axon terminal sprouting from SuM neurons, could contribute to trigger spontaneous seizures within an altered hippocampal intrinsic circuitry.
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Affiliation(s)
- Rabia Soussi
- INSERM, UMR 1106, Institut de Neurosciences des Systèmes - INS, 13385, Marseille, France
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27
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Neo P, Carter D, Zheng Y, Smith P, Darlington C, McNaughton N. Septal elicitation of hippocampal theta rhythm did not repair cognitive and emotional deficits resulting from vestibular lesions. Hippocampus 2011; 22:1176-87. [PMID: 21748822 DOI: 10.1002/hipo.20963] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2011] [Indexed: 02/05/2023]
Abstract
Bilateral vestibular lesions cause atrophy of the hippocampus in humans and subsequent deficits in spatial memory and the processing of emotional stimuli in both rats and humans. Vestibular lesions also impair hippocampal theta rhythm in rats. The aim of the present study was to investigate whether restoring theta rhythm to the hippocampus of a rat, via stimulation of the medial septum, would repair the deficits caused by vestibular lesions. It was hypothesized that the restoration of theta would repair the deficits and the vestibular rats would exhibit behavior and EEG similar to that of the sham rats. Rats were given either sham surgery or bilateral vestibular deafferentation (BVD) followed in a later operation by electrode implants. Half of the lesioned rats received stimulation. Subjects were tested in open field, elevated T-maze and spatial nonmatching to sample tests. BVD caused a deficit in hippocampal theta rhythm. Stimulation restored theta power at a higher frequency in the vestibular-lesioned rats, however, the stimulation did not repair the cognitive and emotional deficits caused by the lesions. It was concluded that stimulation, at least in the form used here, would not be a viable treatment option for vestibular damaged humans.
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Affiliation(s)
- Phoebe Neo
- Department of Psychology, University of Otago, Dunedin, New Zealand
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Blinowska KJ. Review of the methods of determination of directed connectivity from multichannel data. Med Biol Eng Comput 2011; 49:521-9. [PMID: 21298355 PMCID: PMC3097342 DOI: 10.1007/s11517-011-0739-x] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 01/13/2011] [Indexed: 11/24/2022]
Abstract
The methods applied for estimation of functional connectivity from multichannel data are described with special emphasis on the estimators of directedness such as directed transfer function (DTF) and partial directed coherence. These estimators based on multivariate autoregressive model are free of pitfalls connected with application of bivariate measures. The examples of applications illustrating the performance of the methods are given. Time-varying estimators of directedness: short-time DTF and adaptive methods are presented.
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Soussi R, Zhang N, Tahtakran S, Houser CR, Esclapez M. Heterogeneity of the supramammillary-hippocampal pathways: evidence for a unique GABAergic neurotransmitter phenotype and regional differences. Eur J Neurosci 2010; 32:771-85. [PMID: 20722723 PMCID: PMC2974797 DOI: 10.1111/j.1460-9568.2010.07329.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The supramammillary nucleus (SuM) provides substantial projections to the hippocampal formation. This hypothalamic structure is involved in the regulation of hippocampal theta rhythm and therefore the control of hippocampal-dependent cognitive functions as well as emotional behavior. A major goal of this study was to characterize the neurotransmitter identity of the SuM-hippocampal pathways. Our findings demonstrate two distinct neurochemical pathways in rat. The first pathway originates from neurons in the lateral region of the SuM and innervates the supragranular layer of the dorsal dentate gyrus and, to a much lesser extent, the ventral dentate gyrus. This pathway displays a unique dual phenotype for GABAergic and glutamatergic neurotransmission. Axon terminals contain markers of GABAergic neurotransmission, including the synthesizing enzyme of GABA, glutamate decarboxylase 65, and the vesicular GABA transporter and also a marker of glutamatergic neurotransmission, the vesicular glutamate transporter 2. The second pathway originates from neurons in the most posterior and medial part of the SuM and innervates exclusively the inner molecular layer of the ventral dentate gyrus and the CA2/CA3a pyramidal cell layer of the hippocampus. The axon terminals from the medial part of the SuM contain the vesicular glutamate transporter 2 only. These data demonstrate for the first time the heterogeneity of the SuM-hippocampal pathways, not only from an anatomical but also a neurochemical point of view. These pathways, implicated in different neuronal networks, could modulate different hippocampal activities. They are likely to be involved differently in the regulation of hippocampal theta rhythm and associated cognitive functions as well as emotional behavior.
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Affiliation(s)
- Rabia Soussi
- Inserm, U751, Laboratoire Epilepsie et Cognition, Faculté de Médecine Timone, Marseille, F-13005 France
- Aix-Marseille University, Faculté de Médecine Timone, Marseille, F-13005 France
| | - Nianhui Zhang
- Department of Neurobiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095
| | - Siroun Tahtakran
- Department of Neurobiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095
| | - Carolyn R Houser
- Department of Neurobiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095
- Brain Research Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095
- Research Service, Veterans Affairs Greater Los Angeles Healthcare System, West Los Angeles, Los Angeles, California 90073
| | - Monique Esclapez
- Inserm, U751, Laboratoire Epilepsie et Cognition, Faculté de Médecine Timone, Marseille, F-13005 France
- Aix-Marseille University, Faculté de Médecine Timone, Marseille, F-13005 France
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Triphasic dynamics of stimulus-dependent information flow between single neurons in macaque inferior temporal cortex. J Neurosci 2010; 30:10407-21. [PMID: 20685983 DOI: 10.1523/jneurosci.0135-10.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The functional connectivity between cortical neurons is not static and is known to exhibit contextual modulations in terms of the coupling strength. Here we hypothesized that the information flow in a cortical local circuit exhibits complex forward-and-back dynamics, and conducted Granger causality analysis between the neuronal spike trains that were simultaneously recorded from macaque inferior temporal (IT) cortex while the animals performed a visual object discrimination task. Spikes from neuron pairs with a displaced peak on the cross-correlogram (CCG) showed Granger causality in the gamma-frequency range (30-80 Hz) with the dominance in the direction consistent with the CCG peak (forward direction). Although, in a classical view, the displaced CCG peak has been interpreted as an indicative of a pauci-synaptic serial linkage, temporal dynamics of the gamma Granger causality after stimulus onset exhibited a more complex triphasic pattern, with a transient forward component followed by a slowly developing backward component and subsequent reappearance of the forward component. These triphasic dynamics of causality were not explained by the firing rate dynamics and were not observed for cell pairs that exhibited a center peak on the CCG. Furthermore, temporal dynamics of Granger causality depended on the feature configuration within the presented object. Together, these results demonstrate that the classical view of functional connectivity could be expanded to incorporate more complex forward-and-back dynamics and also imply that multistage processing in the recognition of visual objects might be implemented by multiphasic dynamics of directional information flow between single neurons in a local circuit in the IT cortex.
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Ruan M, Young CK, McNaughton N. Minimal driving of hippocampal theta by the supramammillary nucleus during water maze learning. Hippocampus 2010; 21:1074-81. [PMID: 20865741 DOI: 10.1002/hipo.20821] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2010] [Indexed: 11/05/2022]
Abstract
Previous studies have shown only modest effects of supramammillary nucleus (SuM) dysfunction on theta frequency and learning in the water maze (WM), with larger effects in other tasks. However, theta recorded from SuM, and used to trigger the production of theta-like oscillations in the hippocampus, produced reversal of the deficit in WM learning produced by theta blocking. We explored this apparent inconsistency by analyzing the relationship between SuM and hippocampal theta in the control group of this theta-blocking experiment using coherence, phase analysis, and the directed transfer function. We found little evidence of an influence of SuM on the hippocampus in the bulk of WM learning-with some possibility of SuM becoming involved briefly later in learning. A learning-related increase in coherence was observed in conjunction with gradual phase reorganization of hippocampal theta in relation to SuM theta. This change in phase dynamics between the two structures was also correlated with a relative increase of the estimated direction of theta propagation from the SuM to the hippocampus. These results are consistent with the previous weak effects of SuM lesions and suggest that the use of SuM as a source to trigger hippocampal theta and recover function is likely to be due to coherence between SuM and some other structure that normally controls hippocampal theta during WM learning.
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Affiliation(s)
- Ming Ruan
- Department of Psychology and the Neuroscience Research Centre, University of Otago, Dunedin, New Zealand
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32
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Shin J. Theta rhythm heterogeneity in humans. Clin Neurophysiol 2010; 121:456-7. [DOI: 10.1016/j.clinph.2009.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 12/02/2009] [Accepted: 12/04/2009] [Indexed: 11/24/2022]
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Ito M, Shirao T, Doya K, Sekino Y. Three-dimensional distribution of Fos-positive neurons in the supramammillary nucleus of the rat exposed to novel environment. Neurosci Res 2009; 64:397-402. [DOI: 10.1016/j.neures.2009.04.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 04/16/2009] [Accepted: 04/17/2009] [Indexed: 11/28/2022]
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Young CK, Eggermont JJ. Coupling of mesoscopic brain oscillations: recent advances in analytical and theoretical perspectives. Prog Neurobiol 2009; 89:61-78. [PMID: 19549556 DOI: 10.1016/j.pneurobio.2009.06.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 04/27/2009] [Accepted: 06/15/2009] [Indexed: 01/12/2023]
Abstract
Oscillatory brain activities have been traditionally studied in the context of how oscillations at a single frequency recorded from a single area could reveal functional insights. Recent advances in methodology used in signal analysis have revealed that cross-frequency coupling, within or between functional related areas, is more informative in determining the possible roles played by brain oscillations. In this review, we begin by describing the cellular basis of oscillatory field potentials and its theorized as well as demonstrated role in brain function. The recent development of mathematical tools that allow the investigation of cross-frequency and cross-area oscillation coupling will be presented and discussed in the context of recent advances in oscillation research based on animal data. Particularly, some pitfalls and caveats of methods currently available are discussed. Data generated from the application of examined techniques are integrated back into the theoretical framework regarding the functional role of brain oscillations. We suggest that the coupling of oscillatory activities at different frequencies between brain regions is crucial for understanding the brain from a functional ensemble perspective. Effort should be directed to elucidate how cross-frequency and area coupling are modulated and controlled. To achieve this, only the correct application of analytical tools may shed light on the intricacies of information representation, generation, binding, encoding, storage and retrieval in the brain.
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Affiliation(s)
- Calvin K Young
- Behavioural Neuroscience Group, Department of Psychology, University of Calgary, Calgary, AB, Canada
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35
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Méndez-López M, Méndez M, López L, Arias JL. Spatial working memory in Wistar rats: Brain sex differences in metabolic activity. Brain Res Bull 2009; 79:187-92. [DOI: 10.1016/j.brainresbull.2009.02.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/16/2009] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
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Blinowska KJ, Trzaskowski B, Kaminski M, Kus R. Multivariate autoregressive model for a study of phylogenetic diversity. Gene 2009; 435:104-18. [PMID: 19393180 DOI: 10.1016/j.gene.2009.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 12/17/2008] [Accepted: 01/05/2009] [Indexed: 12/01/2022]
Abstract
We present a computationally effective model to parameterize DNA sequences in a way describing comprehensively its auto and cross-correlation structure. The approach is based on four-channel Multivariate Autoregressive Model (MVAR). The model was applied to a study of genes from the globin family for 6 vertebrate species. First, the sequences were coded as four signals (corresponding to the nucleotides), which were fitted to a four-channel MVAR. From the correlation matrices the vectors of model coefficients were calculated as functions of the nucleotide distance. The between-chromosomes and inter-species differences were best distinguished in the cross-coefficients binding different nucleotide sequences. For clustering purposes different metrics were tested and then two clustering procedures (Nearest Neighbor and UPGMA) were applied. The clustering trees and consensus trees were constructed for exons, introns and whole genes. The results were in agreement with the known dependencies between the chromosomes of the globin family. The orthological genes for different species were grouped together. Inside these groups the phylogenetically close organisms were localized in proximity.
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Affiliation(s)
- K J Blinowska
- Department of Biomedical Physics, Warsaw University, Poland.
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37
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Baseline hippocampal theta oscillation speeds correlate with rate of operant task acquisition. Behav Brain Res 2008; 190:152-5. [PMID: 18378012 DOI: 10.1016/j.bbr.2008.02.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 02/12/2008] [Accepted: 02/12/2008] [Indexed: 11/21/2022]
Abstract
Many lines of evidence indicate that theta rhythm, a prominent neural oscillatory mode found in the mammalian hippocampus, plays a key role in the acquisition, processing, and retrieval of memories. However, a predictive neurophysiological feature of the baseline theta rhythm that correlates with the learning rate across different animals has yet to be identified. Here we show that the mean theta rhythm speed observed during baseline periods of immobility has a strong positive correlation with the rate at which rats learn an operant task. This relationship is observed across rats, during both quiet waking (r=0.82; p<0.01) and paradoxical sleep (r=0.83; p<0.01), suggesting that the basal theta frequency relates to basic neurological processes that are important in the acquisition of operant behavior.
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Zhang R, Sun XZ, Cui C, Sakata-Haga H, Sawada K, Ye C, Fukui Y. Spatial learning and expression of neural cell adhesion molecule L1 in rats X-irradiated prenatally. THE JOURNAL OF MEDICAL INVESTIGATION 2007; 54:322-30. [PMID: 17878682 DOI: 10.2152/jmi.54.322] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The present study was designed to present evidence to clarify the relationships between learning ability, neuronal cell adhesion molecule L1 expression and hippocampal structural changes in the rat model received X-irradiation at an embryonic stage (E15). Water maze task indicated that all of the irradiated rats failed to learn the task in the whole training procedure. Their latency to the platform and swimming distance were significant differences from those sham-treated controls. Histological studies showed that the hippocampal ectopias induced by X-rays in the CA1 were involved in the spatial learning impairment, in which they hampered normal processes in learning development and transmission of information. Number, size and positions of the ectopias in the dorsal parts of the hippocampus were confirmed to be related to degrees of spatial learning impairment. On the other hand, L1 expression in the hippocampus was examined with Western blot analysis. The results indicated a lower content of L1 in the irradiated rats. A decrease in L1 might be one of reasons to cause disorganization of the septohippocampal pathways. These findings suggest some mechanisms of spatial learning impairment can be attributed to the formation of the hippocampal ectopias and redaction of L1 following prenatal exposure to X-irradiation.
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Affiliation(s)
- Rui Zhang
- Department of Anatomy and Developmental Neurobiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
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Kocsis B, Li S, Hajos M. Behavior-dependent modulation of hippocampal EEG activity by the selective norepinephrine reuptake inhibitor reboxetine in rats. Hippocampus 2007; 17:627-33. [PMID: 17492692 DOI: 10.1002/hipo.20299] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Both active wakefulness and rapid eye movement sleep (REM) give rise to rhythmic synchronized hippocampal field oscillations, known as theta activity. Antidepressant drugs, including norepinephrine re-uptake inhibitors are proven to diminish REM sleep, and REM sleep-related hippocampal theta oscillation. Since reboxetine, a highly selective norepinephrine re-uptake inhibitor has been shown to block REM sleep, but induce or facilitate hippocampal theta activity in anesthetized rats, the current study investigated the effects of reboxetine on stage- and behavior dependent theta activity. Polysomnographic recordings, which included hippocampal field potentials at the hippocampal fissure, were carried out in rats for 8 h during the light phase of the circadian cycle. Theta rhythm was analyzed during three different behavioral conditions: REM sleep, during motor activity in a familiar environment, and during exploration in a novel environment. We found that, compared with REM sleep, theta power was relatively low during periods of active wakefulness when the animal was in the familiar home cage, but considerably increased during exploration in a novel environment. Reboxetine suppressed sleep and thus abolished REM sleep-related hippocampal theta rhythm, attenuated theta in the familiar environment, and significantly enhanced theta oscillations associated with exploratory behavior. Our findings demonstrate a state- and behavior-dependent modulation of hippocampal theta activity by reboxetine, providing further evidence for a prominent role of norepinephrine in arousal and focused or selective attention.
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Affiliation(s)
- Bernat Kocsis
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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40
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Abstract
Rapid eye movement (REM) sleep is a behavioural state characterized by activation of the cortical and hippocampal EEG, rapid eye movements and muscle atonia. For the past 30 years, the most widely accepted neural circuitry model for the regulation of REM sleep has emphasized reciprocal inhibitory interactions between pontine brainstem monoaminergic and cholinergic neurons. In general support of the reciprocal interaction model, neuropharmacological studies have shown that cholinergic agonists promote REM sleep and muscarinic antagonists and monoamines inhibit REM sleep. It has nevertheless proven difficult to reconcile both the theoretical framework of this model and the pharmacological data with the fact that selective lesions of either cholinergic or monoaminergic (noradrenergic, serotoninergic or dopaminergic) nuclei in the brainstem have relatively limited effects on REM sleep. Recent work by our laboratory has revealed the presence of non-cholinergic and non-monoaminergic mutually inhibitory REM-off and REM-on areas in the mesopontine tegmentum that may form the neuroanatomical basis of the switching circuitry for REM sleep. These findings posit a REM switching circuitry model that is analogous to an electronic 'flip-flop' switch. In this flip-flop switch arrangement, GABAergic REM-on neurons (located in the sublaterodorsal tegmental nucleus (SLD)) inhibit GABAergic REM-off neurons (located in the ventrolateral periaqueductal grey matter (vlPAG) and lateral pontine tegmentum (LPT)) and vice versa. In the REM-on area are two populations of glutamatergic neurons, the first of which projects to the basal forebrain and regulates EEG components of REM sleep and the second of which projects to the ventromedial medulla and spinal cord and regulates atonia during REM sleep. Our findings demonstrating independent pathways mediating atonia and the EEG components of REM provide a basis for their occasional dissociation in pathological states, e.g. REM sleep behaviour disorder.
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Affiliation(s)
- Patrick M Fuller
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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McNaughton N, Kocsis B, Hajós M. Elicited hippocampal theta rhythm: a screen for anxiolytic and procognitive drugs through changes in hippocampal function? Behav Pharmacol 2007; 18:329-46. [PMID: 17762505 DOI: 10.1097/fbp.0b013e3282ee82e3] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hippocampal damage produces cognitive deficits similar to dementia and changes in emotional and motivated reactions similar to anxiolytic drugs. The gross electrical activity of the hippocampus contains a marked 'theta rhythm'. This is a relatively high voltage sinusoidal waveform, resulting from synchronous phasic firing of cells, variation in which correlates with behavioural state. Like the hippocampus, theta has been linked to both cognitive and emotional functions. Critically, it has recently been shown that restoration of theta-like rhythmicity can restore lost cognitive function. We review the effects of systemic administration of drugs on hippocampal theta elicited by stimulation of the reticular formation. We conclude that reductions in the frequency of reticular-elicited theta provide what is currently the best in-vivo means of detecting antianxiety drugs. We also suggest that increases in the power of reticular-elicited theta could detect drugs useful in the treatment of disorders, such as dementia, that involve memory loss. We argue that these functionally distinct effects should be seen as indirect and that each results from a change in a single form of cognitive-emotional processing that particularly involves the hippocampus.
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Affiliation(s)
- Neil McNaughton
- Department of Psychology, University of Otago, Dunedin, New Zealand.
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Li S, Topchiy I, Kocsis B. The effect of atropine administered in the medial septum or hippocampus on high- and low-frequency theta rhythms in the hippocampus of urethane anesthetized rats. Synapse 2007; 61:412-9. [PMID: 17372965 DOI: 10.1002/syn.20388] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cholinergic mechanisms are critical for the generation of hippocampal theta rhythm. Cholinergic innervation of the hippocampus originates from the medial septum (MS) and cholinergic receptors are expressed in both the MS and hippocampus. In this study, we compared the effects of the muscarinic receptor antagonist atropine in the MS and the hippocampus on theta generation. Hippocampal theta rhythm was elicited by electrical stimulation of the pontine reticular formation using series of stimuli with varying intensities. Atropine was administered either systemically (50 mg/kg i.p.) or locally in the MS (microdialysis; 25 and 75 mM for 30 or 90 min) or in the hippocampus on one side (microinjection; 20 or 40 ug). The relative power at the peak theta frequency was calculated and averaged over episodes of low-intensity and high-intensity stimulations. We found that atropine drastically reduced theta rhythmic synchronization when injected in either location. After MS administration of atropine, however, high-frequency theta elicited by high-intensity stimuli was more resistant (58% and 67% decrease after 25 mM and 75 mM atropine, respectively) than slow theta elicited by low-intensity stimuli (86% and 91% decrease). There was no significant difference between the powers of the two oscillations after hippocampal injections (70-75% decrease). We conclude that the theta suppressing effect of atropine involves both hippocampal and septal mechanisms and that low-frequency theta as compared with fast theta rhythm is more sensitive to muscarinic acetylcholine receptor antagonism in the MS but not in the hippocampus.
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Affiliation(s)
- Shaomin Li
- Laboratory of Neurophysiology, Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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43
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McNaughton N, Ruan M, Woodnorth MA. Restoring theta-like rhythmicity in rats restores initial learning in the Morris water maze. Hippocampus 2007; 16:1102-10. [PMID: 17068783 DOI: 10.1002/hipo.20235] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neural activity often becomes rhythmic during mental processing. But there has been no direct proof that rhythmicity, per se, is important for mental function. We assessed this issue in relation to the contribution of hippocampal theta-frequency rhythmicity to learning in the Morris water maze by blocking theta (and other septal inputs to the hippocampus) and then using electrical stimulation to restore rhythmicity. We injected tetracaine into the medial septal area, and so blocked septal input to the hippocampus in rats throughout 16 consecutive trials in a Morris water maze. Rats with no hippocampal theta also showed no initial learning in the maze. Theta rhythmicity in the supramammillary area remained after septal blockade, and we used this to trigger electrical stimulation of the fornix superior. This substantially restored hippocampal theta-like rhythmicity throughout training at a normal frequency but with abnormal wave forms. This treatment applied throughout training substantially restored initial learning. Fixed frequency (7.7 Hz) stimulation produced rhythmic activity and a brief improvement in learning. Irregular stimulation with an average frequency of 7.7 Hz produced little rhythmicity and little improvement in learning. These results demonstrate that brain rhythmicity, per se, can be important for mental processing even when the detailed information originally carried by neurons is lost and when the reinstated pattern of population firing is not normal. The results suggest that the precise frequency of rhythmicity may be important for hippocampal function. Functional rhythmicity needs, therefore, to be included in neural models of cognitive processing. The success of our procedure also suggests that simple alterations of rhythmicity could be used to ameliorate deficits in learning and memory. (c) 2006 Wiley-Liss, Inc.
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Affiliation(s)
- Neil McNaughton
- Department of Psychology, Neuroscience Research Centre, University of Otago, Dunedin, New Zealand.
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45
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Nerad L, McNaughton N. The septal EEG suggests a distributed organization of the pacemaker of hippocampal theta in the rat. Eur J Neurosci 2006; 24:155-66. [PMID: 16882013 DOI: 10.1111/j.1460-9568.2006.04902.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Individual neurons in the medial septum and diagonal band fire in phase with, and appear to act as a 'pacemaker' of, the hippocampal theta rhythm. We investigated the relationships of periodic EEG both among various parts of the septum and with dorsal hippocampal theta recorded concurrently in freely moving rats. Most septal sites showed theta rhythm concurrent with hippocampal theta during locomotion. However, periods with theta at hippocampal but not septal sites were more frequent than the reverse. Theta waves in different parts of the septum were synchronized with each other but medial septal sites showed less frequent theta than other sites. The phase delays between medial and lateral septal sites were < 10 ms, suggesting that the hippocampus does not act as a simple relay between the two. Spectral analysis revealed periods (> 5 s) of theta at hippocampal sites co-occurring with rhythms at multiple septal sites that were slower than theta. Even slower were the 'slow septal waves' (mean 2.7 Hz), which were present in the absence of locomotion and did not 'drive' the hippocampus. Our data suggest that the pacemaker of hippocampal theta may best be thought of as a set of functionally differentiated components rather than as a single homogenous unit.
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Affiliation(s)
- Ludek Nerad
- Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences, Prague 4, Czech Republic
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Li S, Varga V, Sik A, Kocsis B. GABAergic control of the ascending input from the median raphe nucleus to the limbic system. J Neurophysiol 2005; 94:2561-74. [PMID: 15944232 PMCID: PMC1224729 DOI: 10.1152/jn.00379.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The median raphe nucleus (MRN) is the primary source of serotonergic afferents to the limbic system that are generally considered to suppress hippocampal theta oscillations. GABA receptors are expressed in the MRN by serotonergic and nonserotonergic cells, including GABAergic and glutamatergic neurons. This study investigated the mechanisms by which the fluctuating GABA tone in the MRN leads to induction or suppression of hippocampal theta rhythm. We found that MRN application of the GABA(A) agonist muscimol (0.05-1.0 mM) or GABA(B) agonist baclofen (0.2 mM) by reverse microdialysis had strong theta promoting effects. The GABA(A) antagonist bicuculline infused in low concentrations (0.1, 0.2 mM) eliminated theta rhythm. A short period of theta activity of higher than normal frequency preceded hippocampal desynchronization in 46% of rats. Bicuculline in larger concentrations (0.5, 1.0, 2.0 mM) resulted in a biphasic response of an initial short (<10 min) hippocampal desynchronization followed by stable theta rhythm that lasted as long as the infusion continued. The frequency and amplitude of theta waves were higher than in control recordings and the oscillations showed a conspicuous intermittent character. Hippocampal theta rhythm elicited by MRN administration of bicuculline could be completely (0.5 mM bicuculline) or partially (1.0 mM bicuculline) blocked by simultaneous infusion of the GABA(B) antagonist CGP35348. Our findings suggest that the GABAergic network may have two opposing functions in the MRN: relieving the theta-generators from serotonergic inhibition and regulating the activity of a theta-promoting circuitry by the fluctuating GABA tone. The two mechanisms may be involved in different functions.
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Affiliation(s)
- Shaomin Li
- Laboratory of Neurophysiology, Departments of Psychiatry at Massachusetts Mental Health Center and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Viktor Varga
- Laboratory of Neurophysiology, Departments of Psychiatry at Massachusetts Mental Health Center and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
- National Institute of Neurosurgery, Budapest Hungary
| | | | - Bernat Kocsis
- Laboratory of Neurophysiology, Departments of Psychiatry at Massachusetts Mental Health Center and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
- National Institute of Neurosurgery, Budapest Hungary
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