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Kniffin A, Bangasser DA, Parikh V. Septohippocampal cholinergic system at the intersection of stress and cognition: Current trends and translational implications. Eur J Neurosci 2024; 59:2155-2180. [PMID: 37118907 PMCID: PMC10875782 DOI: 10.1111/ejn.15999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 04/21/2023] [Accepted: 04/22/2023] [Indexed: 04/30/2023]
Abstract
Deficits in hippocampus-dependent memory processes are common across psychiatric and neurodegenerative disorders such as depression, anxiety and Alzheimer's disease. Moreover, stress is a major environmental risk factor for these pathologies and it exerts detrimental effects on hippocampal functioning via the activation of hypothalamic-pituitary-adrenal (HPA) axis. The medial septum cholinergic neurons extensively innervate the hippocampus. Although, the cholinergic septohippocampal pathway (SHP) has long been implicated in learning and memory, its involvement in mediating the adaptive and maladaptive impact of stress on mnemonic processes remains less clear. Here, we discuss current research highlighting the contributions of cholinergic SHP in modulating memory encoding, consolidation and retrieval. Then, we present evidence supporting the view that neurobiological interactions between HPA axis stress response and cholinergic signalling impact hippocampal computations. Finally, we critically discuss potential challenges and opportunities to target cholinergic SHP as a therapeutic strategy to improve cognitive impairments in stress-related disorders. We argue that such efforts should consider recent conceptualisations on the dynamic nature of cholinergic signalling in modulating distinct subcomponents of memory and its interactions with cellular substrates that regulate the adaptive stress response.
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Affiliation(s)
- Alyssa Kniffin
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA 19122
| | - Debra A. Bangasser
- Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA
| | - Vinay Parikh
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA 19122
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2
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Dmitrieva E, Malkov A. Optogenetic stimulation of medial septal glutamatergic neurons modulates theta-gamma coupling in the hippocampus. Neurobiol Learn Mem 2024; 211:107929. [PMID: 38685526 DOI: 10.1016/j.nlm.2024.107929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 04/08/2024] [Accepted: 04/24/2024] [Indexed: 05/02/2024]
Abstract
Hippocampal cross-frequency theta-gamma coupling (TGC) is a basic mechanism for information processing, retrieval, and consolidation of long-term and working memory. While the role of entorhinal afferents in the modulation of hippocampal TGC is widely accepted, the influence of other main input to the hippocampus, from the medial septal area (MSA, the pacemaker of the hippocampal theta rhythm) is poorly understood. Optogenetics allows us to explore how different neuronal populations of septohippocampal circuits control neuronal oscillations in vivo. Rhythmic activation of septal glutamatergic neurons has been shown to drive hippocampal theta oscillations, but the role of these neuronal populations in information processing during theta activation has remained unclear. Here we investigated the influence of phasic activation of MSA glutamatergic neurons expressing channelrhodopsin II on theta-gamma coupling in the hippocampus. During the experiment, local field potentials of MSA and hippocampus of freely behaving mice were modulated by 470 nm light flashes with theta frequency (2-10) Hz. It was shown that both the power and the strength of modulation of gamma rhythm nested on hippocampal theta waves depend on the frequency of stimulation. The modulation of the amplitude of slow gamma rhythm (30-50 Hz) prevailed over modulation of fast gamma (55-100 Hz) during flash trains and the observed effects were specific for theta stimulation of MSA. We discuss the possibility that phasic depolarization of septal glutamatergic neurons controls theta-gamma coupling in the hippocampus and plays a role in memory retrieval and consolidation.
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Affiliation(s)
- Elena Dmitrieva
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Pushchino, Russia
| | - Anton Malkov
- Institute of Theoretical and Experimental Biophysics Russian Academy of Sciences, Pushchino, Russia.
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3
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Kazmierska-Grebowska P, Jankowski MM, MacIver MB. Missing Puzzle Pieces in Dementia Research: HCN Channels and Theta Oscillations. Aging Dis 2024; 15:22-42. [PMID: 37450922 PMCID: PMC10796085 DOI: 10.14336/ad.2023.0607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/07/2023] [Indexed: 07/18/2023] Open
Abstract
Increasing evidence indicates a role of hyperpolarization activated cation (HCN) channels in controlling the resting membrane potential, pacemaker activity, memory formation, sleep, and arousal. Their disfunction may be associated with the development of epilepsy and age-related memory decline. Neuronal hyperexcitability involved in epileptogenesis and EEG desynchronization occur in the course of dementia in human Alzheimer's Disease (AD) and animal models, nevertheless the underlying ionic and cellular mechanisms of these effects are not well understood. Some suggest that theta rhythms involved in memory formation could be used as a marker of memory disturbances in the course of neurogenerative diseases, including AD. This review focusses on the interplay between hyperpolarization HCN channels, theta oscillations, memory formation and their role(s) in dementias, including AD. While individually, each of these factors have been linked to each other with strong supportive evidence, we hope here to expand this linkage to a more inclusive picture. Thus, HCN channels could provide a molecular target for developing new therapeutic agents for preventing and/or treating dementia.
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Affiliation(s)
| | - Maciej M. Jankowski
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
- BioTechMed Center, Multimedia Systems Department, Faculty of Electronics, Telecommunications, and Informatics, Gdansk University of Technology, Gdansk, Poland.Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland.
| | - M. Bruce MacIver
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of of Medicine, Stanford University, CA, USA.
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4
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Etter G, Carmichael JE, Williams S. Linking temporal coordination of hippocampal activity to memory function. Front Cell Neurosci 2023; 17:1233849. [PMID: 37720546 PMCID: PMC10501408 DOI: 10.3389/fncel.2023.1233849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/01/2023] [Indexed: 09/19/2023] Open
Abstract
Oscillations in neural activity are widespread throughout the brain and can be observed at the population level through the local field potential. These rhythmic patterns are associated with cycles of excitability and are thought to coordinate networks of neurons, in turn facilitating effective communication both within local circuits and across brain regions. In the hippocampus, theta rhythms (4-12 Hz) could contribute to several key physiological mechanisms including long-range synchrony, plasticity, and at the behavioral scale, support memory encoding and retrieval. While neurons in the hippocampus appear to be temporally coordinated by theta oscillations, they also tend to fire in sequences that are developmentally preconfigured. Although loss of theta rhythmicity impairs memory, these sequences of spatiotemporal representations persist in conditions of altered hippocampal oscillations. The focus of this review is to disentangle the relative contribution of hippocampal oscillations from single-neuron activity in learning and memory. We first review cellular, anatomical, and physiological mechanisms underlying the generation and maintenance of hippocampal rhythms and how they contribute to memory function. We propose candidate hypotheses for how septohippocampal oscillations could support memory function while not contributing directly to hippocampal sequences. In particular, we explore how theta rhythms could coordinate the integration of upstream signals in the hippocampus to form future decisions, the relevance of such integration to downstream regions, as well as setting the stage for behavioral timescale synaptic plasticity. Finally, we leverage stimulation-based treatment in Alzheimer's disease conditions as an opportunity to assess the sufficiency of hippocampal oscillations for memory function.
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Affiliation(s)
| | | | - Sylvain Williams
- Department of Psychiatry, Douglas Mental Health Research Institute, McGill University, Montreal, QC, Canada
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5
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Alexander AS, Robinson JC, Stern CE, Hasselmo ME. Gated transformations from egocentric to allocentric reference frames involving retrosplenial cortex, entorhinal cortex, and hippocampus. Hippocampus 2023; 33:465-487. [PMID: 36861201 PMCID: PMC10403145 DOI: 10.1002/hipo.23513] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 01/22/2023] [Accepted: 01/25/2023] [Indexed: 03/03/2023]
Abstract
This paper reviews the recent experimental finding that neurons in behaving rodents show egocentric coding of the environment in a number of structures associated with the hippocampus. Many animals generating behavior on the basis of sensory input must deal with the transformation of coordinates from the egocentric position of sensory input relative to the animal, into an allocentric framework concerning the position of multiple goals and objects relative to each other in the environment. Neurons in retrosplenial cortex show egocentric coding of the position of boundaries in relation to an animal. These neuronal responses are discussed in relation to existing models of the transformation from egocentric to allocentric coordinates using gain fields and a new model proposing transformations of phase coding that differ from current models. The same type of transformations could allow hierarchical representations of complex scenes. The responses in rodents are also discussed in comparison to work on coordinate transformations in humans and non-human primates.
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Affiliation(s)
- Andrew S Alexander
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Jennifer C Robinson
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Chantal E Stern
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Michael E Hasselmo
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
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6
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Ferrier FJ, Saul I, Khoury N, Ruiz AJ, Lao EJP, Escobar I, Dave KR, Young JI, Perez-Pinzon MA. Post cardiac arrest physical exercise mitigates cell death in the septal and thalamic nuclei and ameliorates contextual fear conditioning deficits in rats. J Cereb Blood Flow Metab 2023; 43:446-459. [PMID: 36369732 PMCID: PMC9941858 DOI: 10.1177/0271678x221137539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 11/14/2022]
Abstract
A major concern for cardiac arrest (CA) survivors is the manifestation of long-term cognitive impairments. Physical exercise (PE) is a well-established approach to improve cognitive functions under certain pathological conditions. We previously showed that PE post-CA mitigates cognitive deficits, but the underlying mechanisms remain unknown. To define neuroprotective mechanisms, we analyzed whether PE post-CA protects neurons involved in memory. We first performed a contextual fear conditioning (CFC) test to confirm that PE post-CA preserves memory in rats. We then conducted a cell-count analysis and determined the number of live cells in the hippocampus, and septal and thalamic nuclei, all areas involved in cognitive functions. Lastly, we performed RNA-seq to determine PE post-CA effect on gene expression. Following CA, exercised rats had preserved CFC memory than sham PE animals. Despite this outcome, PE post-CA did not protect hippocampal cells from dying. However, PE ameliorated cell death in septal and thalamic nuclei compared to sham PE animals, suggesting that these nuclei are crucial in mitigating cognitive decline post-CA. Interestingly, PE affected regulation of genes related to neuroinflammation, plasticity, and cell death. These findings reveal potential mechanisms whereby PE post-CA preserves cognitive functions by protecting septal and thalamic cells via gene regulation.
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Affiliation(s)
- Fernando J Ferrier
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Neuroscience Program, University of Miami Leonard M. Miller
School of Medicine, Miami FL
| | - Isabel Saul
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Department of Neurology, University of Miami Leonard M. Miller
School of Medicine, Miami, FL, USA
| | - Nathalie Khoury
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Neuroscience Program, University of Miami Leonard M. Miller
School of Medicine, Miami FL
| | - Alexander J Ruiz
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
| | - Efrain J Perez Lao
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Neuroscience Program, University of Miami Leonard M. Miller
School of Medicine, Miami FL
- Hussman Institute for Human Genetics, University of Miami
Leonard M. Miller School of Medicine, Miami, FL, USA
| | - Iris Escobar
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Neuroscience Program, University of Miami Leonard M. Miller
School of Medicine, Miami FL
| | - Kunjan R Dave
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Neuroscience Program, University of Miami Leonard M. Miller
School of Medicine, Miami FL
- Department of Neurology, University of Miami Leonard M. Miller
School of Medicine, Miami, FL, USA
| | - Juan I Young
- Hussman Institute for Human Genetics, University of Miami
Leonard M. Miller School of Medicine, Miami, FL, USA
| | - Miguel A Perez-Pinzon
- Peritz Scheinberg Cerebral Vascular Disease Research
Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami,
FL, USA
- Neuroscience Program, University of Miami Leonard M. Miller
School of Medicine, Miami FL
- Department of Neurology, University of Miami Leonard M. Miller
School of Medicine, Miami, FL, USA
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7
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Salimi-Nezhad N, Missault S, Notario-Reinoso A, Hassani A, Amiri M, Keliris GA. The impact of selective and non-selective medial septum stimulation on hippocampal neuronal oscillations: A study based on modeling and experiments. Neurobiol Dis 2023; 180:106052. [PMID: 36822547 DOI: 10.1016/j.nbd.2023.106052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 02/09/2023] [Accepted: 02/19/2023] [Indexed: 02/23/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder with a rising socioeconomic impact on societies. The hippocampus (HPC), which plays an important role in AD, is affected in the early stages. The medial septum (MS) in the forebrain provides major cholinergic input to the HPC and has been shown to play a significant role in generating oscillations in hippocampal neurons. Cholinergic neurons in the basal forebrain are particularly vulnerable to neurodegeneration in AD. To better understand the role of MS neurons including the cholinergic, glutamatergic, and GABAergic subpopulations in generating the well-known brain rhythms in HPC including delta, theta, slow gamma, and fast gamma oscillations, we designed a detailed computational model of the septohippocampal pathway. We validated the results of our model, using electrophysiological recordings in HPC with and without stimulation of the cholinergic neurons in MS using designer receptors exclusively activated by designer drugs (DREADDs) in healthy male ChAT-cre rats. Then, we eliminated 75% of the MS cholinergic neurons in the model to simulate degeneration in AD. A series of selective and non-selective stimulations of the remaining MS neurons were performed to understand the dynamics of oscillation regulation in the HPC during the degenerated state. In this way, appropriate stimulation strategies able to normalize the aberrant oscillations are proposed. We found that selectively stimulating the remaining healthy cholinergic neurons was sufficient for network recovery and compare this to stimulating other subpopulations and a non-selective stimulation of all MS neurons. Our data provide valuable information for the development of new therapeutic strategies in AD and a tool to test and predict the outcome of potential theranostic manipulations.
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Affiliation(s)
- Nima Salimi-Nezhad
- Medical Biology Research Center, Institute of Health Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | | | - Anaïs Notario-Reinoso
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
| | - Atefe Hassani
- Medical Technology Research Center, Institute of Health Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mahmood Amiri
- Medical Technology Research Center, Institute of Health Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Georgios A Keliris
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; Institute of Computer Science, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece.
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Optogenetic frequency scrambling of hippocampal theta oscillations dissociates working memory retrieval from hippocampal spatiotemporal codes. Nat Commun 2023; 14:410. [PMID: 36697399 PMCID: PMC9877037 DOI: 10.1038/s41467-023-35825-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 01/03/2023] [Indexed: 01/26/2023] Open
Abstract
The precise temporal coordination of activity in the brain is thought to be fundamental for memory function. Inhibitory neurons in the medial septum provide a prominent source of innervation to the hippocampus and play a major role in controlling hippocampal theta (~8 Hz) oscillations. While pharmacological inhibition of medial septal neurons is known to disrupt memory, the exact role of septal inhibitory neurons in regulating hippocampal representations and memory is not fully understood. Here, we dissociate the role of theta rhythms in spatiotemporal coding and memory using an all-optical interrogation and recording approach. We find that optogenetic frequency scrambling stimulations abolish theta oscillations and modulate a portion of neurons in the hippocampus. Such stimulation decreased episodic and working memory retrieval while leaving hippocampal spatiotemporal codes intact. Our study suggests that theta rhythms play an essential role in memory but may not be necessary for hippocampal spatiotemporal codes.
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Mysin I, Shubina L. Hippocampal non-theta state: The "Janus face" of information processing. Front Neural Circuits 2023; 17:1134705. [PMID: 36960401 PMCID: PMC10027749 DOI: 10.3389/fncir.2023.1134705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 02/14/2023] [Indexed: 03/09/2023] Open
Abstract
The vast majority of studies on hippocampal rhythms have been conducted on animals or humans in situations where their attention was focused on external stimuli or solving cognitive tasks. These studies formed the basis for the idea that rhythmical activity coordinates the work of neurons during information processing. However, at rest, when attention is not directed to external stimuli, brain rhythms do not disappear, although the parameters of oscillatory activity change. What is the functional load of rhythmical activity at rest? Hippocampal oscillatory activity during rest is called the non-theta state, as opposed to the theta state, a characteristic activity during active behavior. We dedicate our review to discussing the present state of the art in the research of the non-theta state. The key provisions of the review are as follows: (1) the non-theta state has its own characteristics of oscillatory and neuronal activity; (2) hippocampal non-theta state is possibly caused and maintained by change of rhythmicity of medial septal input under the influence of raphe nuclei; (3) there is no consensus in the literature about cognitive functions of the non-theta-non-ripple state; and (4) the antagonistic relationship between theta and delta rhythms observed in rodents is not always observed in humans. Most attention is paid to the non-theta-non-ripple state, since this aspect of hippocampal activity has not been investigated properly and discussed in reviews.
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Chronic Intermittent Ethanol Exposure Dysregulates Nucleus Basalis Magnocellularis Afferents in the Basolateral Amygdala. eNeuro 2022; 9:ENEURO.0164-22.2022. [PMID: 36280288 PMCID: PMC9668348 DOI: 10.1523/eneuro.0164-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/22/2022] [Accepted: 08/25/2022] [Indexed: 12/24/2022] Open
Abstract
Nucleus basalis magnocellularis (NBM) cholinergic projections to the basolateral amygdala (BLA) regulate the acquisition and consolidation of fear-like and anxiety-like behaviors. However, it is unclear whether the alterations in the NBM-BLA circuit promote negative affect during ethanol withdrawal (WD). Therefore, we performed ex vivo whole-cell patch-clamp electrophysiology in both the NBM and the BLA of male Sprague Dawley rats following 10 d of chronic intermittent ethanol (CIE) exposure and 24 h of WD. We found that CIE exposure and withdrawal enhanced the neuronal excitability of NBM putative "cholinergic" neurons. We subsequently used optogenetics to directly manipulate NBM terminal activity within the BLA and measure cholinergic modulation of glutamatergic afferents and BLA pyramidal neurons. Our findings indicate that CIE and withdrawal upregulate NBM cholinergic facilitation of glutamate release via activation of presynaptic nicotinic acetylcholine receptors (AChRs). Ethanol withdrawal-induced increases in NBM terminal activity also enhance BLA pyramidal neuron firing. Collectively, our results provide a novel characterization of the NBM-BLA circuit and suggest that CIE-dependent modifications to NBM afferents enhance BLA pyramidal neuron activity during ethanol withdrawal.
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Magno L, Asgarian Z, Apanaviciute M, Milner Y, Bengoa-Vergniory N, Rubin AN, Kessaris N. Fate mapping reveals mixed embryonic origin and unique developmental codes of mouse forebrain septal neurons. Commun Biol 2022; 5:1137. [PMID: 36302841 PMCID: PMC9613704 DOI: 10.1038/s42003-022-04066-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/04/2022] [Indexed: 11/08/2022] Open
Abstract
The septum is a key structure at the core of the forebrain that integrates inputs and relays information to other brain areas to support cognition and behaviours such as feeding and locomotion. Underlying these functions is a rich diversity of neuronal types and an intricate complexity of wiring across and within the septal region. We currently have very little understanding of how septal neuronal diversity emerges during development. Using transgenic mice expressing Cre in different subsets of telencephalic precursors we explored the origins of the three main neuronal types of the septal complex: GABAergic, cholinergic and glutamatergic neurons. We find that septal neurons originate from distinct neuroepithelial domains of the developing septum and are born at different embryonic time points. An exception to this is the GABAergic medial septal Parvalbumin-expressing population which is generated outside the septum from surrounding germinal zones. We identify the transcription factor BSX as being expressed in the developing glutamatergic neuron population. Embryonic elimination of BSX in the septum results in a reduction of septal glutamatergic cell numbers and a consequent deficit in locomotion. Further refinement of septal neuron diversity is needed to understand the multiple roles of septal neurons and their contribution to distinct behaviours.
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Affiliation(s)
- Lorenza Magno
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK.
| | - Zeinab Asgarian
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Migle Apanaviciute
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Yasmin Milner
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Nora Bengoa-Vergniory
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Anna Noren Rubin
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Nicoletta Kessaris
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK.
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12
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Griguoli M, Pimpinella D. Medial septum: relevance for social memory. Front Neural Circuits 2022; 16:965172. [PMID: 36082110 PMCID: PMC9445153 DOI: 10.3389/fncir.2022.965172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Animal species are named social when they develop the capability of complex behaviors based on interactions with conspecifics that include communication, aggression, mating and parental behavior, crucial for well-being and survival. The underpinning of such complex behaviors is social memory, namely the capacity to discriminate between familiar and novel individuals. The Medial Septum (MS), a region localized in the basal forebrain, is part of the brain network involved in social memory formation. MS receives several cortical and subcortical synaptic and neuromodulatory inputs that make it an important hub in processing social information relevant for social memory. Particular attention is paid to synaptic inputs that control both the MS and the CA2 region of the hippocampus, one of the major MS output, that has been causally linked to social memory. In this review article, we will provide an overview of local and long range connectivity that allows MS to integrate and process social information. Furthermore, we will summarize previous strategies used to determine how MS controls social memory in different animal species. Finally, we will discuss the impact of an altered MS signaling on social memory in animal models and patients affected by neurodevelopmental and neurodegenerative disorders, including autism and Alzheimer’s Disease.
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Affiliation(s)
- Marilena Griguoli
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
- Institute of Molecular Biology and Pathology of the National Council of Research (IBPM-CNR), Rome, Italy
- *Correspondence: Marilena Griguoli
| | - Domenico Pimpinella
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
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13
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Solórzano Hernández E, Cervantes Alfaro JM, Figueroa Rosales R, Gutiérrez Guzmán BÉ, López Vázquez MÁ, Olvera Cortés ME. Septal medial/diagonal band of Broca citalopram infusion reduces place learning efficiency and alters septohippocampal theta learning-related activity in rats. Behav Brain Res 2022; 435:114056. [PMID: 35963580 DOI: 10.1016/j.bbr.2022.114056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/26/2022]
Abstract
Increases in power and frequency of hippocampal theta activity have been related to efficient place learning and memory acquisition in hippocampal-dependent tests. The complex medial septum-diagonal band of Broca (MS/DBB) is the pacemaker of hippocampal theta activity, influenced by the ascending synchronizing system, and modulated by serotonergic raphe medial afferents, acting on cholinergic and GABAergic septal neurons. The suppression of hippocampal theta expression and the modulation of hippocampal learning and memory are attributed to serotonin. To simultaneously test these hypotheses, a daily local serotonin increase was induced by citalopram (CIT) infusion (100 µM, 0.88 µl, 0.2 µl/m) 15 min before training in the Morris water maze. The theta activity was recorded in the MS/DBB, dentate gyrus (DG) and CA1 of one group infused with artificial cerebrospinal liquid (ACL) and the other with CIT on Days 1-6 of training. After a probe trial (Day 7) and one resting day, the treatments were reversed (Days 8-11). The CIT MS/DBB infusion in the first 6 training days reduced the efficiency of spatial learning in association with reduced power in the DG, reduced MS/DBB-DG coherence, increased DG-CA1 coherence, and a lack of a negative correlation between MS/DBB power and swam distances. No effect of the CIT occurred once the information was acquired under ACL training. These results support a role of serotonin, in acting on the MS/DBB in the fine tuning of hippocampal learning and memory efficiency through the modulation of learning-related theta activity power and septohipocampal synchronization.
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Affiliation(s)
- Eduardo Solórzano Hernández
- Laboratorio de Neurociencias, División de Estudios de Posgrado, Facultad de Ciencias Médicas y Biológicas "Dr. Ignacio Chávez", Universidad Michoacana de San Nicolás de Hidalgo, Mexico; Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Mexico.
| | - José Miguel Cervantes Alfaro
- Laboratorio de Neurociencias, División de Estudios de Posgrado, Facultad de Ciencias Médicas y Biológicas "Dr. Ignacio Chávez", Universidad Michoacana de San Nicolás de Hidalgo, Mexico.
| | - Rosalinda Figueroa Rosales
- Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Mexico.
| | - Blanca Érika Gutiérrez Guzmán
- Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Mexico.
| | - Miguel Ángel López Vázquez
- Laboratorio de Neuroplasticidad, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Mexico.
| | - María Esther Olvera Cortés
- Laboratorio de Neurofisiología Experimental, División de Neurociencias, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Mexico.
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14
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Huygens synchronization of medial septal pacemaker neurons generates hippocampal theta oscillation. Cell Rep 2022; 40:111149. [PMID: 35926456 DOI: 10.1016/j.celrep.2022.111149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/06/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022] Open
Abstract
Episodic learning and memory retrieval are dependent on hippocampal theta oscillation, thought to rely on the GABAergic network of the medial septum (MS). To test how this network achieves theta synchrony, we recorded MS neurons and hippocampal local field potential simultaneously in anesthetized and awake mice and rats. We show that MS pacemakers synchronize their individual rhythmicity frequencies, akin to coupled pendulum clocks as observed by Huygens. We optogenetically identified them as parvalbumin-expressing GABAergic neurons, while MS glutamatergic neurons provide tonic excitation sufficient to induce theta. In accordance, waxing and waning tonic excitation is sufficient to toggle between theta and non-theta states in a network model of single-compartment inhibitory pacemaker neurons. These results provide experimental and theoretical support to a frequency-synchronization mechanism for pacing hippocampal theta, which may serve as an inspirational prototype for synchronization processes in the central nervous system from Nematoda to Arthropoda to Chordate and Vertebrate phyla.
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15
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Cole ER, Grogan DP, Laxpati NG, Fernandez AM, Skelton HM, Isbaine F, Gutekunst CA, Gross RE. Evidence supporting deep brain stimulation of the medial septum in the treatment of temporal lobe epilepsy. Epilepsia 2022; 63:2192-2213. [PMID: 35698897 DOI: 10.1111/epi.17326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 12/28/2022]
Abstract
Electrical brain stimulation has become an essential treatment option for more than one third of epilepsy patients who are resistant to pharmacological therapy and are not candidates for surgical resection. However, currently approved stimulation paradigms achieve only moderate success, on average providing approximately 75% reduction in seizure frequency and extended periods of seizure freedom in nearly 20% of patients. Outcomes from electrical stimulation may be improved through the identification of novel anatomical targets, particularly those with significant anatomical and functional connectivity to the epileptogenic zone. Multiple studies have investigated the medial septal nucleus (i.e., medial septum) as such a target for the treatment of mesial temporal lobe epilepsy. The medial septum is a small midline nucleus that provides a critical functional role in modulating the hippocampal theta rhythm, a 4-7-Hz electrophysiological oscillation mechanistically associated with memory and higher order cognition in both rodents and humans. Elevated theta oscillations are thought to represent a seizure-resistant network activity state, suggesting that electrical neuromodulation of the medial septum and restoration of theta-rhythmic physiology may not only reduce seizure frequency, but also restore cognitive comorbidities associated with mesial temporal lobe epilepsy. Here, we review the anatomical and physiological function of the septohippocampal network, evidence for seizure-resistant effects of the theta rhythm, and the results of stimulation experiments across both rodent and human studies, to argue that deep brain stimulation of the medial septum holds potential to provide an effective neuromodulation treatment for mesial temporal lobe epilepsy. We conclude by discussing the considerations necessary for further evaluating this treatment paradigm with a clinical trial.
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Affiliation(s)
- Eric R Cole
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | | | - Nealen G Laxpati
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Alejandra M Fernandez
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Henry M Skelton
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Faical Isbaine
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Robert E Gross
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA.,Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
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16
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Burjanadze MA, Dashniani MG, Solomonia RO, Beselia GV, Tsverava L, Lagani V, Chkhikvishvili NC, Naneishvili TL, Kruashvili LB, Chighladze MR. Age-related changes in medial septal cholinergic and GABAergic projection neurons and hippocampal neurotransmitter receptors: relationship with memory impairment. Exp Brain Res 2022; 240:1589-1604. [PMID: 35357523 DOI: 10.1007/s00221-022-06354-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/21/2022] [Indexed: 11/24/2022]
Abstract
The hippocampus, which provides cognitive functions, has been shown to become highly vulnerable during aging. One important modulator of the hippocampal neural network is the medial septum (MS). The present study attempts to determine how age-related mnemonic dysfunction is associated with neurochemical changes in the septohippocampal (SH) system, using behavioral and immunochemical experiments performed on young-adult, middle-aged and aged rats. According to these behavioral results, the aged and around 52.8% of middle-aged rats (within the "middle-aged-impaired" sub-group) showed both impaired spatial reference memory in the Morris water maze and habituation in the open field. Immunohistochemical studies revealed a significant decrease in the number of MS choline acetyltransferase immunoreactive cells in the aged and all middle-aged rats, in comparison to the young; however the number of gamma-aminobutyric acid-ergic (GABAergic) parvalbumin immunoreactive cells was higher in middle-aged-impaired and older rats compared to young and middle-aged-unimpaired rats. Western Blot analysis moreover showed a decrease in the level of expression of cholinergic, GABAergic and glutamatergic receptors in the hippocampus of middle-aged-impaired and aged rats in contrast to middle-aged-unimpaired and young rats. The present results demonstrate for the first time that a decrease in the expression level of hippocampal receptors in naturally aged rats with impaired cognitive abilities occurs in parallel with an increase in the number of GABAergic neurons in the MS, and it highlights the particular importance of inhibitory signaling in the SH network for memory function.
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Affiliation(s)
- Maia A Burjanadze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.
| | - Manana G Dashniani
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Revaz O Solomonia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.,Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Gela V Beselia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.,Department of Physiology and Pharmacology, Petre Shotadze Tbilisi Medical Academy, 0144, Tbilisi, Georgia
| | - Lia Tsverava
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.,Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Vincenzo Lagani
- Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Nino C Chkhikvishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Temur L Naneishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Lali B Kruashvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Mariam R Chighladze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
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17
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Gu Z, Yakel JL. Cholinergic Regulation of Hippocampal Theta Rhythm. Biomedicines 2022; 10:biomedicines10040745. [PMID: 35453495 PMCID: PMC9027244 DOI: 10.3390/biomedicines10040745] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/16/2022] Open
Abstract
Cholinergic regulation of hippocampal theta rhythm has been proposed as one of the central mechanisms underlying hippocampal functions including spatial memory encoding. However, cholinergic transmission has been traditionally associated with atropine-sensitive type II hippocampal theta oscillations that occur during alert immobility or in urethane-anesthetized animals. The role of cholinergic regulation of type I theta oscillations in behaving animals is much less clear. Recent studies strongly suggest that both cholinergic muscarinic and nicotinic receptors do actively regulate type I hippocampal theta oscillations and thus provide the cholinergic mechanism for theta-associated hippocampal learning. Septal cholinergic activation can regulate hippocampal circuit and theta expression either through direct septohippocampal cholinergic projections, or through septal glutamatergic and GABAergic neurons, that can precisely entrain hippocampal theta rhythmicity.
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18
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Szlaga A, Sambak P, Trenk A, Gugula A, Singleton CE, Drwiega G, Blasiak T, Ma S, Gundlach AL, Blasiak A. Functional Neuroanatomy of the Rat Nucleus Incertus–Medial Septum Tract: Implications for the Cell-Specific Control of the Septohippocampal Pathway. Front Cell Neurosci 2022; 16:836116. [PMID: 35281300 PMCID: PMC8913896 DOI: 10.3389/fncel.2022.836116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
The medial septum (MS) is critically involved in theta rhythmogenesis and control of the hippocampal network, with which it is reciprocally connected. MS activity is influenced by brainstem structures, including the stress-sensitive, nucleus incertus (NI), the main source of the neuropeptide relaxin-3 (RLN3). In the current study, we conducted a comprehensive neurochemical and electrophysiological characterization of NI neurons innervating the MS in the rat, by employing classical and viral-based neural tract-tracing and electrophysiological approaches, and multiplex fluorescent in situ hybridization. We confirmed earlier reports that the MS is innervated by RLN3 NI neurons and documented putative glutamatergic (vGlut2 mRNA-expressing) neurons as a relevant NI neuronal population within the NI–MS tract. Moreover, we observed that NI neurons innervating MS can display a dual phenotype for GABAergic and glutamatergic neurotransmission, and that 40% of MS-projecting NI neurons express the corticotropin-releasing hormone-1 receptor. We demonstrated that an identified cholecystokinin (CCK)-positive NI neuronal population is part of the NI–MS tract, and that RLN3 and CCK NI neurons belong to a neuronal pool expressing the calcium-binding proteins, calbindin and calretinin. Finally, our electrophysiological studies revealed that MS is innervated by A-type potassium current-expressing, type I NI neurons, and that type I and II NI neurons differ markedly in their neurophysiological properties. Together these findings indicate that the MS is controlled by a discrete NI neuronal network with specific electrophysiological and neurochemical features; and these data are of particular importance for understanding neuronal mechanisms underlying the control of the septohippocampal system and related behaviors.
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Affiliation(s)
- Agata Szlaga
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Patryk Sambak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Caitlin E. Singleton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Gniewosz Drwiega
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Tomasz Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
- *Correspondence: Anna Blasiak,
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19
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Lamotrigine Attenuates Neuronal Excitability, Depresses GABA Synaptic Inhibition, and Modulates Theta Rhythms in Rat Hippocampus. Int J Mol Sci 2021; 22:ijms222413604. [PMID: 34948401 PMCID: PMC8705017 DOI: 10.3390/ijms222413604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/29/2021] [Accepted: 12/05/2021] [Indexed: 12/03/2022] Open
Abstract
Theta oscillations generated in hippocampal (HPC) and cortical neuronal networks are involved in various aspects of brain function, including sensorimotor integration, movement planning, memory formation and attention. Disruptions of theta rhythms are present in individuals with brain disorders, including epilepsy and Alzheimer’s disease. Theta rhythm generation involves a specific interplay between cellular (ion channel) and network (synaptic) mechanisms. HCN channels are theta modulators, and several medications are known to enhance their activity. We investigated how different doses of lamotrigine (LTG), an HCN channel modulator, and antiepileptic and neuroprotective agent, would affect HPC theta rhythms in acute HPC slices (in vitro) and anaesthetized rats (in vivo). Whole-cell patch clamp recordings revealed that LTG decreased GABAA-fast transmission in CA3 cells, in vitro. In addition, LTG directly depressed CA3 and CA1 pyramidal neuron excitability. These effects were partially blocked by ZD 7288, a selective HCN blocker, and are consistent with decreased excitability associated with antiepileptic actions. Lamotrigine depressed HPC theta oscillations in vitro, also consistent with its neuronal depressant effects. In contrast, it exerted an opposite, enhancing effect, on theta recorded in vivo. The contradictory in vivo and in vitro results indicate that LTG increases ascending theta activating medial septum/entorhinal synaptic inputs that over-power the depressant effects seen in HPC neurons. These results provide new insights into LTG actions and indicate an opportunity to develop more precise therapeutics for the treatment of dementias, memory disorders and epilepsy.
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20
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Robinson JC, Brandon MP. Skipping ahead: A circuit for representing the past, present, and future. eLife 2021; 10:e68795. [PMID: 34647521 PMCID: PMC8516414 DOI: 10.7554/elife.68795] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 09/28/2021] [Indexed: 01/02/2023] Open
Abstract
Envisioning the future is intuitively linked to our ability to remember the past. Within the memory system, substantial work has demonstrated the involvement of the prefrontal cortex and the hippocampus in representing the past and present. Recent data shows that both the prefrontal cortex and the hippocampus encode future trajectories, which are segregated in time by alternating cycles of the theta rhythm. Here, we discuss how information is temporally organized by these brain regions supported by the medial septum, nucleus reuniens, and parahippocampal regions. Finally, we highlight a brain circuit that we predict is essential for the temporal segregation of future scenarios.
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Affiliation(s)
- Jennifer C Robinson
- Department of Psychological and Brain Sciences, Rajen Kilachand Center for Integrated Life Sciences and Engineering, Boston UniversityBostonUnited States
| | - Mark P Brandon
- Department of Psychiatry, Douglas Hospital Research Centre, McGill UniversityMontrealCanada
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21
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Mocellin P, Mikulovic S. The Role of the Medial Septum-Associated Networks in Controlling Locomotion and Motivation to Move. Front Neural Circuits 2021; 15:699798. [PMID: 34366795 PMCID: PMC8340000 DOI: 10.3389/fncir.2021.699798] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 06/28/2021] [Indexed: 12/29/2022] Open
Abstract
The Medial Septum and diagonal Band of Broca (MSDB) was initially studied for its role in locomotion. However, the last several decades were focussed on its intriguing function in theta rhythm generation. Early studies relied on electrical stimulation, lesions and pharmacological manipulation, and reported an inconclusive picture regarding the role of the MSDB circuits. Recent studies using more specific methodologies have started to elucidate the differential role of the MSDB's specific cell populations in controlling both theta rhythm and behaviour. In particular, a novel theory is emerging showing that different MSDB's cell populations project to different brain regions and control distinct aspects of behaviour. While the majority of these behaviours involve movement, increasing evidence suggests that MSDB-related networks govern the motivational aspect of actions, rather than locomotion per se. Here, we review the literature that links MSDB, theta activity, and locomotion and propose open questions, future directions, and methods that could be employed to elucidate the diverse roles of the MSDB-associated networks.
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Affiliation(s)
- Petra Mocellin
- Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
- International Max Planck Research School for Brain and Behavior, Bonn, Germany
| | - Sanja Mikulovic
- Research Group Cognition and Emotion, Leibniz Institute for Neurobiology, Magdeburg, Germany
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22
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A neuromimetic realization of hippocampal CA1 for theta wave generation. Neural Netw 2021; 142:548-563. [PMID: 34340189 DOI: 10.1016/j.neunet.2021.07.002] [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: 11/23/2020] [Revised: 04/29/2021] [Accepted: 07/02/2021] [Indexed: 11/20/2022]
Abstract
Recent advances in neural engineering allowed the development of neuroprostheses which facilitate functionality in people with neurological problems. In this research, a real-time neuromorphic system is proposed to artificially reproduce the theta wave and firing patterns of different neuronal populations in the CA1, a sub-region of the hippocampus. The hippocampal theta oscillations (4-12 Hz) are an important electrophysiological rhythm that contributes in various cognitive functions, including navigation, memory, and novelty detection. The proposed CA1 neuromimetic circuit includes 100 linearized Pinsky-Rinzel neurons and 668 excitatory and inhibitory synapses on a field programmable gate array (FPGA). The implemented spiking neural network of the CA1 includes the main neuronal populations for the theta rhythm generation: excitatory pyramidal cells, PV+ basket cells, and Oriens Lacunosum-Moleculare (OLM) cells which are inhibitory interneurons. Moreover, the main inputs to the CA1 region from the entorhinal cortex via the perforant pathway, the CA3 via Schaffer collaterals, and the medial septum via fimbria-fornix are also implemented on the FPGA using a bursting leaky-integrate and fire (LIF) neuron model. The results of hardware realization show that the proposed CA1 neuromimetic circuit successfully reconstructs the theta oscillations and functionally illustrates the phase relations between firing responses of the different neuronal populations. It is also evaluated the impact of medial septum elimination on the firing patterns of the CA1 neuronal population and the theta wave's characteristics. This neuromorphic system can be considered as a potential platform that opens opportunities for neuroprosthetic applications in future works.
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23
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Takeuchi Y, Nagy AJ, Barcsai L, Li Q, Ohsawa M, Mizuseki K, Berényi A. The Medial Septum as a Potential Target for Treating Brain Disorders Associated With Oscillopathies. Front Neural Circuits 2021; 15:701080. [PMID: 34305537 PMCID: PMC8297467 DOI: 10.3389/fncir.2021.701080] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/14/2021] [Indexed: 12/14/2022] Open
Abstract
The medial septum (MS), as part of the basal forebrain, supports many physiological functions, from sensorimotor integration to cognition. With often reciprocal connections with a broad set of peers at all major divisions of the brain, the MS orchestrates oscillatory neuronal activities throughout the brain. These oscillations are critical in generating sensory and emotional salience, locomotion, maintaining mood, supporting innate anxiety, and governing learning and memory. Accumulating evidence points out that the physiological oscillations under septal influence are frequently disrupted or altered in pathological conditions. Therefore, the MS may be a potential target for treating neurological and psychiatric disorders with abnormal oscillations (oscillopathies) to restore healthy patterns or erase undesired ones. Recent studies have revealed that the patterned stimulation of the MS alleviates symptoms of epilepsy. We discuss here that stimulus timing is a critical determinant of treatment efficacy on multiple time scales. On-demand stimulation may dramatically reduce side effects by not interfering with normal physiological functions. A precise pattern-matched stimulation through adaptive timing governed by the ongoing oscillations is essential to effectively terminate pathological oscillations. The time-targeted strategy for the MS stimulation may provide an effective way of treating multiple disorders including Alzheimer's disease, anxiety/fear, schizophrenia, and depression, as well as pain.
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Affiliation(s)
- Yuichi Takeuchi
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Anett J. Nagy
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Lívia Barcsai
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Qun Li
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Masahiro Ohsawa
- Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Kenji Mizuseki
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Antal Berényi
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
- Neurocybernetics Excellence Center, University of Szeged, Szeged, Hungary
- HCEMM-USZ Magnetotherapeutics Research Group, University of Szeged, Szeged, Hungary
- Neuroscience Institute, New York University, New York, NY, United States
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24
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Vickstrom CR, Liu X, Liu S, Hu MM, Mu L, Hu Y, Yu H, Love SL, Hillard CJ, Liu QS. Role of endocannabinoid signaling in a septohabenular pathway in the regulation of anxiety- and depressive-like behavior. Mol Psychiatry 2021; 26:3178-3191. [PMID: 33093652 PMCID: PMC8060365 DOI: 10.1038/s41380-020-00905-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/17/2020] [Accepted: 10/01/2020] [Indexed: 12/21/2022]
Abstract
Enhancing endocannabinoid signaling produces anxiolytic- and antidepressant-like effects, but the neural circuits involved remain poorly understood. The medial habenula (MHb) is a phylogenetically-conserved epithalamic structure that is a powerful modulator of anxiety- and depressive-like behavior. Here, we show that a robust endocannabinoid signaling system modulates synaptic transmission between the MHb and its sole identified GABA input, the medial septum and nucleus of the diagonal band (MSDB). With RNAscope in situ hybridization, we demonstrate that key enzymes that synthesize or degrade the endocannabinoids 2-arachidonylglycerol (2-AG) or anandamide are expressed in the MHb and MSDB, and that cannabinoid receptor 1 (CB1) is expressed in the MSDB. Electrophysiological recordings in MHb neurons revealed that endogenously-released 2-AG retrogradely depresses GABA input from the MSDB. This endocannabinoid-mediated depolarization-induced suppression of inhibition (DSI) was limited by monoacylglycerol lipase (MAGL) but not by fatty acid amide hydrolase. Anatomic and optogenetic circuit mapping indicated that MSDB GABA neurons monosynaptically project to cholinergic neurons of the ventral MHb. To test the behavioral significance of this MSDB-MHb endocannabinoid signaling, we induced MSDB-specific knockout of CB1 or MAGL via injection of virally-delivered Cre recombinase into the MSDB of Cnr1loxP/loxP or MgllloxP/loxP mice. Relative to control mice, MSDB-specific knockout of CB1 or MAGL bidirectionally modulated 2-AG signaling in the ventral MHb and led to opposing effects on anxiety- and depressive-like behavior. Thus, depression of synaptic GABA release in the MSDB-ventral MHb pathway may represent a potential mechanism whereby endocannabinoids exert anxiolytic and antidepressant-like effects.
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Affiliation(s)
- Casey R Vickstrom
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
| | - Xiaojie Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Shuai Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Meng-Ming Hu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Lianwei Mu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ying Hu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Hao Yu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Santidra L Love
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Cecilia J Hillard
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Qing-Song Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
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25
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McKenna JT, Yang C, Bellio T, Anderson-Chernishof MB, Gamble MC, Hulverson A, McCoy JG, Winston S, Hodges E, Katsuki F, McNally JM, Basheer R, Brown RE. Characterization of basal forebrain glutamate neurons suggests a role in control of arousal and avoidance behavior. Brain Struct Funct 2021; 226:1755-1778. [PMID: 33997911 PMCID: PMC8340131 DOI: 10.1007/s00429-021-02288-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 05/05/2021] [Indexed: 12/25/2022]
Abstract
The basal forebrain (BF) is involved in arousal, attention, and reward processing but the role of individual BF neuronal subtypes is still being uncovered. Glutamatergic neurons are the least well-understood of the three main BF neurotransmitter phenotypes. Here we analyzed the distribution, size, calcium-binding protein content and projections of the major group of BF glutamatergic neurons expressing the vesicular glutamate transporter subtype 2 (vGluT2) and tested the functional effect of activating them. Mice expressing Cre recombinase under the control of the vGluT2 promoter were crossed with a reporter strain expressing the red fluorescent protein, tdTomato, to generate vGluT2-cre-tdTomato mice. Immunohistochemical staining for choline acetyltransferase and a cross with mice expressing green fluorescent protein selectively in GABAergic neurons confirmed that cholinergic, GABAergic and vGluT2+ neurons represent distinct BF subpopulations. Subsets of BF vGluT2+ neurons expressed the calcium-binding proteins calbindin or calretinin, suggesting that multiple subtypes of BF vGluT2+ neurons exist. Anterograde tracing using adeno-associated viral vectors expressing channelrhodopsin2-enhanced yellow fluorescent fusion proteins revealed major projections of BF vGluT2+ neurons to neighboring BF cholinergic and parvalbumin neurons, as well as to extra-BF areas involved in the control of arousal or aversive/rewarding behavior such as the lateral habenula and ventral tegmental area. Optogenetic activation of BF vGluT2+ neurons elicited a striking avoidance of the area where stimulation was given, whereas stimulation of BF parvalbumin or cholinergic neurons did not. Together with previous optogenetic findings suggesting an arousal-promoting role, our findings suggest that BF vGluT2 neurons play a dual role in promoting wakefulness and avoidance behavior.
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Affiliation(s)
- James T McKenna
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Chun Yang
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Thomas Bellio
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
- Stonehill College, Easton, MA, 02357, USA
| | - Marissa B Anderson-Chernishof
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Mackenzie C Gamble
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
- Stonehill College, Easton, MA, 02357, USA
| | - Abigail Hulverson
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
- Stonehill College, Easton, MA, 02357, USA
| | - John G McCoy
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
- Stonehill College, Easton, MA, 02357, USA
| | - Stuart Winston
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Erik Hodges
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Fumi Katsuki
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - James M McNally
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Radhika Basheer
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA
| | - Ritchie E Brown
- Laboratory of Neuroscience, Dept. of Psychiatry, VA Boston Healthcare System and Harvard Medical School, 1400 VFW Parkway, West Roxbury, MA, 02132, USA.
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García-Díaz C, Gil-Miravet I, Albert-Gasco H, Mañas-Ojeda A, Ros-Bernal F, Castillo-Gómez E, Gundlach AL, Olucha-Bordonau FE. Relaxin-3 Innervation From the Nucleus Incertus to the Parahippocampal Cortex of the Rat. Front Neuroanat 2021; 15:674649. [PMID: 34239421 PMCID: PMC8258164 DOI: 10.3389/fnana.2021.674649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/11/2021] [Indexed: 11/13/2022] Open
Abstract
Spatial learning and memory processes depend on anatomical and functional interactions between the hippocampus and the entorhinal cortex. A key neurophysiological component of these processes is hippocampal theta rhythm, which can be driven from subcortical areas including the pontine nucleus incertus (NI). The NI contains the largest population of neurons that produce and presumably release the neuropeptide, relaxin-3, which acts via the G i/o -protein-coupled receptor, relaxin-family peptide 3 receptor (RXFP3). NI activation induces general arousal including hippocampal theta, and inactivation induces impairment of spatial memory acquisition or retrieval. The primary aim of this study was to map the NI/relaxin-3 innervation of the parahippocampal cortex (PHC), including the medial and lateral entorhinal cortex, endopiriform cortex, perirhinal, postrhinal, and ectorhinal cortex, the amygdalohippocampal transition area and posteromedial cortical amygdala. Retrograde tracer injections were placed in different parts of the medial and lateral entorhinal cortex, which produced prominent retrograde labeling in the ipsilateral NI and some labeling in the contralateral NI. Anterograde tracer injections into the NI and immunostaining for relaxin-3 produced fiber labeling in deep layers of all parahippocampal areas and some dispersed fibers in superficial layers. Double-labeling studies revealed that both hippocampal projecting and calcium-binding protein-positive (presumed GABAergic) neurons received a relaxin-3 NI innervation. Some of these fibers also displayed synaptophysin (Syn) immunoreactivity, consistent with the presence of the peptide at synapses; and relaxin-3-positive fibers containing Syn bouton-like staining were frequently observed in contact with hippocampal-projecting or calcium-binding protein-positive neuronal somata and more distal elements. Finally, in situ hybridization studies revealed that entorhinal neurons in the superficial layers, and to a lesser extent in deep layers, contain RXFP3 mRNA. Together, our data support functional actions of the NI/relaxin-3-parahippocampal innervation on processes related to memory, spatial navigation and contextual analysis.
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Affiliation(s)
- Cristina García-Díaz
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Isis Gil-Miravet
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Hector Albert-Gasco
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain.,UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Aroa Mañas-Ojeda
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Francisco Ros-Bernal
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain
| | - Esther Castillo-Gómez
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Francisco E Olucha-Bordonau
- Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Castellón de la Plana, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
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Rong X, Jiang L, Qu M, Hassan SSU, Liu Z. Enhancing Therapeutic Efficacy of Donepezil by Combined Therapy: A Comprehensive Review. Curr Pharm Des 2021; 27:332-344. [PMID: 33100197 DOI: 10.2174/1381612826666201023144836] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/19/2020] [Indexed: 11/22/2022]
Abstract
Combination therapy involving different therapeutic strategies mostly provides more rapid and effective results as compared to monotherapy in diverse areas of clinical practice. The most worldwide famous acetylcholinesterase inhibitor (AChEIs) donepezil for its dominant role in Alzheimer's disease (AD) has also attracted the attention of many pharmaceuticals due to its promising pharmacological potencies such as neuroprotective, muscle relaxant, and sleep inducer. Recently, a combination of donepezil with other agents has displayed better desirable results in managing several disorders, including the most common Alzheimer's disease (AD). This study involves all the data regarding the therapeutic effect of donepezil in its combination with other agents and explains its therapeutic targets and mode of action. Furthermore, this review also puts light on the current status of donepezil with other agents in clinical trials. The combination therapy of donepezil with symptomatic relief drugs and disease-modifying agents opens a new road for treating multiple pathological disorders. To the best of our knowledge, this is the first report encircling all the pharmacologic effects of donepezil in its combination therapy with other agents and their current status in clinical trials.
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Affiliation(s)
- Xi Rong
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China
| | - Liwei Jiang
- Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, 266000, Shandong, China
| | - Meijie Qu
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China
| | - Syed Shams Ul Hassan
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zongchao Liu
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China
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Signalling pathways contributing to learning and memory deficits in the Ts65Dn mouse model of Down syndrome. Neuronal Signal 2021; 5:NS20200011. [PMID: 33763235 PMCID: PMC7955101 DOI: 10.1042/ns20200011] [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: 10/18/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 01/30/2023] Open
Abstract
Down syndrome (DS) is a genetic trisomic disorder that produces life-long changes in physiology and cognition. Many of the changes in learning and memory seen in DS are reminiscent of disorders involving the hippocampal/entorhinal circuit. Mouse models of DS typically involve trisomy of murine chromosome 16 is homologous for many of the genes triplicated in human trisomy 21, and provide us with good models of changes in, and potential pharmacotherapy for, human DS. Recent careful dissection of the Ts65Dn mouse model of DS has revealed differences in key signalling pathways from the basal forebrain to the hippocampus and associated rhinal cortices, as well as changes in the microstructure of the hippocampus itself. In vivo behavioural and electrophysiological studies have shown that Ts65Dn animals have difficulties in spatial memory that mirror hippocampal deficits, and have changes in hippocampal electrophysiological phenomenology that may explain these differences, and align with expectations generated from in vitro exploration of this model. Finally, given the existing data, we will examine the possibility for pharmacotherapy for DS, and outline the work that remains to be done to fully understand this system.
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Yi F, Garrett T, Deisseroth K, Haario H, Stone E, Lawrence JJ. Septohippocampal transmission from parvalbumin-positive neurons features rapid recovery from synaptic depression. Sci Rep 2021; 11:2117. [PMID: 33483520 PMCID: PMC7822967 DOI: 10.1038/s41598-020-80245-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/14/2020] [Indexed: 01/30/2023] Open
Abstract
Parvalbumin-containing projection neurons of the medial-septum-diagonal band of Broca ([Formula: see text]) are essential for hippocampal rhythms and learning operations yet are poorly understood at cellular and synaptic levels. We combined electrophysiological, optogenetic, and modeling approaches to investigate [Formula: see text] neuronal properties. [Formula: see text] neurons had intrinsic membrane properties distinct from acetylcholine- and somatostatin-containing MS-DBB subtypes. Viral expression of the fast-kinetic channelrhodopsin ChETA-YFP elicited action potentials to brief (1-2 ms) 470 nm light pulses. To investigate [Formula: see text] transmission, light pulses at 5-50 Hz frequencies generated trains of inhibitory postsynaptic currents (IPSCs) in CA1 stratum oriens interneurons. Using a similar approach, optogenetic activation of local hippocampal PV ([Formula: see text]) neurons generated trains of [Formula: see text]-mediated IPSCs in CA1 pyramidal neurons. Both synapse types exhibited short-term depression (STD) of IPSCs. However, relative to [Formula: see text] synapses, [Formula: see text] synapses possessed lower initial release probability, transiently resisted STD at gamma (20-50 Hz) frequencies, and recovered more rapidly from synaptic depression. Experimentally-constrained mathematical synapse models explored mechanistic differences. Relative to the [Formula: see text] model, the [Formula: see text] model exhibited higher sensitivity to calcium accumulation, permitting a faster rate of calcium-dependent recovery from STD. In conclusion, resistance of [Formula: see text] synapses to STD during short gamma bursts enables robust long-range GABAergic transmission from MS-DBB to hippocampus.
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Affiliation(s)
- Feng Yi
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - Tavita Garrett
- Vollum Institute Neuroscience Graduate Program, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Karl Deisseroth
- Department of Psychiatry and Behavioral Sciences, Department of Bioengineering, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA
| | - Heikki Haario
- Department of Mathematics and Physics, Lappeenranta University of Technology, Lappeenranta, Finland
| | - Emily Stone
- Department of Mathematical Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - J Josh Lawrence
- Department of Pharmacology and Neuroscience, Garrison Institute on Aging, and Center for Excellence in Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA.
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Acute Effects of Two Different Species of Amyloid- β on Oscillatory Activity and Synaptic Plasticity in the Commissural CA3-CA1 Circuit of the Hippocampus. Neural Plast 2021; 2020:8869526. [PMID: 33381164 PMCID: PMC7765721 DOI: 10.1155/2020/8869526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 11/29/2022] Open
Abstract
Recent evidence indicates that soluble amyloid-β (Aβ) species induce imbalances in excitatory and inhibitory transmission, resulting in neural network functional impairment and cognitive deficits during early stages of Alzheimer's disease (AD). To evaluate the in vivo effects of two soluble Aβ species (Aβ25-35 and Aβ1-40) on commissural CA3-to-CA1 (cCA3-to-CA1) synaptic transmission and plasticity, and CA1 oscillatory activity, we used acute intrahippocampal microinjections in adult anaesthetized male Wistar rats. Soluble Aβ microinjection increased cCA3-to-CA1 synaptic variability without significant changes in synaptic efficiency. High-frequency CA3 stimulation was rendered inefficient by soluble Aβ intrahippocampal injection to induce long-term potentiation and to enhance synaptic variability in CA1, contrasting with what was observed in vehicle-injected subjects. Although soluble Aβ microinjection significantly increased the relative power of γ-band and ripple oscillations and significantly shifted the average vector of θ-to-γ phase-amplitude coupling (PAC) in CA1, it prevented θ-to-γ PAC shift induced by high-frequency CA3 stimulation, opposite to what was observed in vehicle-injected animals. These results provide further evidence that soluble Aβ species induce synaptic dysfunction causing abnormal synaptic variability, impaired long-term plasticity, and deviant oscillatory activity, leading to network activity derailment in the hippocampus.
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Activation and blockade of 5-HT 6 receptor in the medial septum-diagonal band recover working memory in the hemiparkinsonian rats. Brain Res 2020; 1748:147072. [PMID: 32853642 DOI: 10.1016/j.brainres.2020.147072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 01/01/2023]
Abstract
Working memory impairment is a common symptom occurred in Parkinson's disease (PD). The medial septum-diagonal band (MS-DB) complex and 5-HT6 receptor are involved in modulation of cognition. However, their roles in working memory in PD are still unknown. Here, we used behavioral, neurochemical and immunohistochemical approaches to assess the role of MS-DB 5-HT6 receptor in working memory in unilateral 6-hydroxydopamie (6-OHDA)-induced PD rats. Intra-MS-DB injection of 5-HT6 receptor agonist WAY208466 (3, 6 and 12 μg/rat) enhanced working memory and increased dopamine (DA) and noradrenaline (NA) levels in the medial prefrontal cortex (mPFC) and hippocampus in sham and 6-OHDA-lesioned rats. The dose that produced significant effect on working memory in 6-OHDA-lesioned rats was lower than that in sham rats, indicating hypersensitivity of 5-HT6 receptor after lesioning. Intra-MS-DB injection of 5-HT6 receptor antagonist SB258585 (2, 4 and 8 μg/rat) alleviated working memory deficits and increased DA level in the mPFC and hippocampus and NA level in the mPFC in 6-OHDA-lesioned rats while having no effect in sham rats, suggesting that SB258585 did not change normal cognitive status. These results suggest that activation and blockade of MS-DB 5-HT6 receptor recovered working memory in 6-OHDA-lesioned rats, which is probably related to changes in monoamine levels in the mPFC and hippocampus.
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Dashniani MG, Burjanadze MA, Chkhikvishvili NC, Solomonia RO, Kandashvili M, Naneishvili TL, Beselia GV, Kruashvili LB, Chighladze MR. Modulation of spatial memory and expression of hippocampal neurotransmitter receptors by selective lesion of medial septal cholinergic and GABAergic neurons. Exp Brain Res 2020; 238:2385-2397. [PMID: 32770352 DOI: 10.1007/s00221-020-05889-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 07/20/2020] [Indexed: 11/30/2022]
Abstract
The medial septum (MS) is an important modulator of hippocampal function. The degree of damage in which the particular set of septo-hippocampal projections contributes to the deficits of spatial memory with concomitant changes of hippocampal receptors expression has not been studied till present. Therefore, we investigated spatial memory and the expression level of cholinergic (α7 nACh and M1), GABAergic (α1 subunit of GABAA) and glutamatergic (NR2B subunit of NMDA and GluR 1 subunit of AMPA) receptors in the hippocampus following selective lesions of cholinergic and GABAergic septo-hippocampal projection. Learning process and long-term spatial memory were assessed using a Morris water maze. The obtained results revealed that in contrast to cholinergic lesions, rats with MS GABAergic lesions exhibit a retention deficit in 3 days after training. Western blot analyses revealed the MS cholinergic lesions have significant effect on the expression level of the M1 mACh receptors, while MS GABAergic lesions induce dramatic modulations of hippocampal glutamatergic, cholinergic and GABAergic receptors expression. These results for the first time demonstrated that selective lesions of MS cholinergic and GABAergic neurons differentially affect long-term spatial memory and the memory deficit after MS GABAergic lesion is paralleled with significant changes of hippocampal glutamate, GABA and acetylcholine receptors expression.
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Affiliation(s)
- Manana G Dashniani
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.
| | - Maia A Burjanadze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Nino C Chkhikvishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Revaz O Solomonia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
- Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Manana Kandashvili
- Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Temur L Naneishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Gela V Beselia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
- Department of Physiology and Pharmacology, Petre Shotadze Tbilisi Medical Academy, 0144, Tbilisi, Georgia
| | - Lali B Kruashvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Mariam R Chighladze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
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Dobryakova YV, Stepanichev MY, Markevich VA, Bolshakov AP. Long-term potentiation in the hippocampal CA3 to CA1 synapses may be induced in vivo by activation of septal cholinergic inputs. Int J Neurosci 2020; 132:1-7. [PMID: 32916077 DOI: 10.1080/00207454.2020.1822834] [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: 05/11/2020] [Revised: 08/27/2020] [Accepted: 09/04/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE/AIM The role of cholinergic neurotransmission in the hippocampus remains controversial since different studies showed either no influence or its modulatory effect on glutamatergic hippocampal synapses. It remains unclear whether septal cholinergic input can modulate plasticity of synapses formed by CA3 pyramids on CA1 neurons. The aim of the study was to clarify the role of septal input in the development of LTP in this synapse. MATERIALS AND METHODS We recorded in vivo in rats under urethane anesthesia focal excitatory postsynaptic potential (fEPSP) characteristics in CA1 area after stimulation of the ventral hippocampal commissure (VHC), which contains both CA3 axons innervating CA1 neurons and cholinergic axons coming from the medial septum. We performed two series of experiments in which LTP was induced by tetanization of either VHC or medial septal area (MSA). Degeneration of cholinergic neurons in MSA was induced by intraseptal injection of 192IgG-saporin. RESULTS In both experimental series, tetanization induced an increase in fEPSP amplitude which lasted for at least 40 min after tetanic stimulation, although tetanization of VHC induced a larger increase in fEPSP amplitude compared to MSA tetanization. Elimination of septal cholinergic neurons by 192IgG-saporin abolished LTP development in both experimental series. This suppression of LTP in animals with cholinergic deficit was not due to loss of hippocampal neurons. CONCLUSIONS Our data suggest that activation of septal cholinergic fibers during tetanization is a critical factor of LTP induction in the hippocampal CA3 to CA1 synapses.
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Affiliation(s)
- Y V Dobryakova
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
| | - M Yu Stepanichev
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
| | - V A Markevich
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
| | - A P Bolshakov
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
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Sonnenschein SF, Gomes FV, Grace AA. Dysregulation of Midbrain Dopamine System and the Pathophysiology of Schizophrenia. Front Psychiatry 2020; 11:613. [PMID: 32719622 PMCID: PMC7350524 DOI: 10.3389/fpsyt.2020.00613] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/12/2020] [Indexed: 11/25/2022] Open
Abstract
Dysregulation of the dopamine system is central to many models of the pathophysiology of psychosis in schizophrenia. However, emerging evidence suggests that this dysregulation is driven by the disruption of upstream circuits that provide afferent control of midbrain dopamine neurons. Furthermore, stress can profoundly disrupt this regulatory circuit, particularly when it is presented at critical vulnerable prepubertal time points. This review will discuss the dopamine system and the circuits that regulate it, focusing on the hippocampus, medial prefrontal cortex, thalamic nuclei, and medial septum, and the impact of stress. A greater understanding of the regulation of the dopamine system and its disruption in schizophrenia may provide a more complete neurobiological framework to interpret clinical findings and develop novel treatments.
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Affiliation(s)
- Susan F. Sonnenschein
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Felipe V. Gomes
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Anthony A. Grace
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States
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The Firing of Theta State-Related Septal Cholinergic Neurons Disrupt Hippocampal Ripple Oscillations via Muscarinic Receptors. J Neurosci 2020; 40:3591-3603. [PMID: 32265261 DOI: 10.1523/jneurosci.1568-19.2020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 01/16/2023] Open
Abstract
The septo-hippocampal cholinergic system is critical for hippocampal learning and memory. However, a quantitative description of the in vivo firing patterns and physiological function of medial septal (MS) cholinergic neurons is still missing. In this study, we combined optogenetics with multichannel in vivo recording and recorded MS cholinergic neuron firings in freely behaving male mice for 5.5-72 h. We found that their firing activities were highly correlated with hippocampal theta states. MS cholinergic neurons were highly active during theta-dominant epochs, such as active exploration and rapid eye movement sleep, but almost silent during non-theta epochs, such as slow-wave sleep (SWS). Interestingly, optogenetic activation of these MS cholinergic neurons during SWS suppressed CA1 ripple oscillations. This suppression could be rescued by muscarinic M2 or M4 receptor antagonists. These results suggest the following important physiological function of MS cholinergic neurons: maintaining high hippocampal acetylcholine level by persistent firing during theta epochs, consequently suppressing ripples and allowing theta oscillations to dominate.SIGNIFICANCE STATEMENT The major source of acetylcholine in the hippocampus comes from the medial septum. Early experiments found that lesions to the MS result in the disappearance of hippocampal theta oscillation, which leads to speculation that the septo-hippocampal cholinergic projection contributing to theta oscillation. In this article, by long-term recording of MS cholinergic neurons, we found that they show a theta state-related firing pattern. However, optogenetically activating these neurons shows little effect on theta rhythm in the hippocampus. Instead, we found that activating MS cholinergic neurons during slow-wave sleep could suppress hippocampal ripple oscillations. This suppression is mediated by muscarinic M2 and M4 receptors.
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Katona L, Hartwich K, Tomioka R, Somogyi J, Roberts JDB, Wagner K, Joshi A, Klausberger T, Rockland KS, Somogyi P. Synaptic organisation and behaviour-dependent activity of mGluR8a-innervated GABAergic trilaminar cells projecting from the hippocampus to the subiculum. Brain Struct Funct 2020; 225:705-734. [PMID: 32016558 PMCID: PMC7046583 DOI: 10.1007/s00429-020-02029-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/16/2020] [Indexed: 02/07/2023]
Abstract
In the hippocampal CA1 area, the GABAergic trilaminar cells have their axon distributed locally in three layers and also innervate the subiculum. Trilaminar cells have a high level of somato-dendritic muscarinic M2 acetylcholine receptor, lack somatostatin expression and their presynaptic inputs are enriched in mGluR8a. But the origin of their inputs and their behaviour-dependent activity remain to be characterised. Here we demonstrate that (1) GABAergic neurons with the molecular features of trilaminar cells are present in CA1 and CA3 in both rats and mice. (2) Trilaminar cells receive mGluR8a-enriched GABAergic inputs, e.g. from the medial septum, which are probably susceptible to hetero-synaptic modulation of neurotransmitter release by group III mGluRs. (3) An electron microscopic analysis identifies trilaminar cell output synapses with specialised postsynaptic densities and a strong bias towards interneurons as targets, including parvalbumin-expressing cells in the CA1 area. (4) Recordings in freely moving rats revealed the network state-dependent segregation of trilaminar cell activity, with reduced firing during movement, but substantial increase in activity with prolonged burst firing (> 200 Hz) during slow wave sleep. We predict that the behaviour-dependent temporal dynamics of trilaminar cell firing are regulated by their specialised inhibitory inputs. Trilaminar cells might support glutamatergic principal cells by disinhibition and mediate the binding of neuronal assemblies between the hippocampus and the subiculum via the transient inhibition of local interneurons.
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Affiliation(s)
- Linda Katona
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Katja Hartwich
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Ryohei Tomioka
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
- Department of Morphological Neural Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Jozsef Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - J David B Roberts
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Kristina Wagner
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Department of Physiology, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, USA
| | - Thomas Klausberger
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, 1090, Vienna, Austria
| | - Kathleen S Rockland
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
- Department of Anatomy and Neurobiology, Boston University School of Medicine, 72 East Concord St., Boston, MA, 02118, USA
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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Etter G, van der Veldt S, Manseau F, Zarrinkoub I, Trillaud-Doppia E, Williams S. Optogenetic gamma stimulation rescues memory impairments in an Alzheimer's disease mouse model. Nat Commun 2019; 10:5322. [PMID: 31757962 PMCID: PMC6876640 DOI: 10.1038/s41467-019-13260-9] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 10/30/2019] [Indexed: 01/08/2023] Open
Abstract
Slow gamma oscillations (30-60 Hz) correlate with retrieval of spatial memory. Altered slow gamma oscillations have been observed in Alzheimer's disease. Here, we use the J20-APP AD mouse model that displays spatial memory loss as well as reduced slow gamma amplitude and phase-amplitude coupling to theta oscillations phase. To restore gamma oscillations in the hippocampus, we used optogenetics to activate medial septal parvalbumin neurons at different frequencies. We show that optogenetic stimulation of parvalbumin neurons at 40 Hz (but not 80 Hz) restores hippocampal slow gamma oscillations amplitude, and phase-amplitude coupling of the J20 AD mouse model. Restoration of slow gamma oscillations during retrieval rescued spatial memory in mice despite significant plaque deposition. These results support the role of slow gamma oscillations in memory and suggest that optogenetic stimulation of medial septal parvalbumin neurons at 40 Hz could provide a novel strategy for treating memory deficits in AD.
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Affiliation(s)
- Guillaume Etter
- McGill University & Douglas Mental Health University Institute, Montreal, Canada
| | | | - Frédéric Manseau
- McGill University & Douglas Mental Health University Institute, Montreal, Canada
| | - Iman Zarrinkoub
- McGill University & Douglas Mental Health University Institute, Montreal, Canada
| | | | - Sylvain Williams
- McGill University & Douglas Mental Health University Institute, Montreal, Canada.
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38
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Sheeran WM, Ahmed OJ. The neural circuitry supporting successful spatial navigation despite variable movement speeds. Neurosci Biobehav Rev 2019; 108:821-833. [PMID: 31760048 DOI: 10.1016/j.neubiorev.2019.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/30/2019] [Accepted: 11/18/2019] [Indexed: 12/18/2022]
Abstract
Ants who have successfully navigated the long distance between their foraging spot and their nest dozens of times will drastically overshoot their destination if the size of their legs is doubled by the addition of stilts. This observation reflects a navigational strategy called path integration, a strategy also utilized by mammals. Path integration necessitates that animals keep track of their movement speed and use it to precisely and instantly modify where they think they are and where they want to go. Here we review the neural circuitry that has evolved to integrate speed and space. We start with the rate and temporal codes for speed in the hippocampus and work backwards towards the motor and sensory systems. We highlight the need for experiments designed to differentiate the respective contributions of motor efference copy versus sensory inputs. In particular, we discuss the importance of high-resolution tracking of the latency of speed-encoding as a precise way to disentangle the sensory versus motor computations that enable successful spatial navigation at very different speeds.
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Affiliation(s)
- William M Sheeran
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular, Cellular & Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Omar J Ahmed
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, MI 48109, USA.
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39
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Lu NN, Tan C, Sun NH, Shao LX, Liu XX, Gao YP, Tao RR, Jiang Q, Wang CK, Huang JY, Zhao K, Wang GF, Liu ZR, Fukunaga K, Lu YM, Han F. Cholinergic Grb2-Associated-Binding Protein 1 Regulates Cognitive Function. Cereb Cortex 2019; 28:2391-2404. [PMID: 28591834 DOI: 10.1093/cercor/bhx141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 05/21/2017] [Indexed: 12/21/2022] Open
Abstract
Grb2-associated-binding protein 1 (Gab1) is a docking/scaffolding molecule known to play an important role in cell growth and survival. Here, we report that Gab1 is decreased in cholinergic neurons in Alzheimer's disease (AD) patients and in a mouse model of AD. In mice, selective ablation of Gab1 in cholinergic neurons in the medial septum impaired learning and memory and hippocampal long-term potentiation. Gab1 ablation also inhibited SK channels, leading to an increase in firing in septal cholinergic neurons. Gab1 overexpression, on the other hand, improved cognitive function and restored hippocampal CaMKII autorphosphorylation in AD mice. These results suggest that Gab1 plays an important role in the pathophysiology of AD and may represent a novel therapeutic target for diseases involving cholinergic dysfunction.
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Affiliation(s)
- Nan-Nan Lu
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chao Tan
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ning-He Sun
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ling-Xiao Shao
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiu-Xiu Liu
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China.,School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang, China
| | - Yin-Ping Gao
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China.,School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang, China
| | - Rong-Rong Tao
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Quan Jiang
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cheng-Kun Wang
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ji-Yun Huang
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kui Zhao
- Department of PET Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Guang-Fa Wang
- Department of PET Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Zhi-Rong Liu
- Department of Neurology, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai, Japan
| | - Ying-Mei Lu
- School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang, China.,Key Laboratory of Medical Neurobiology of Ministry of Health of China, Department of Neurobiology,Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feng Han
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
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40
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Mysin IE, Kitchigina VF, Kazanovich YB. Phase relations of theta oscillations in a computer model of the hippocampal CA1 field: Key role of Schaffer collaterals. Neural Netw 2019; 116:119-138. [DOI: 10.1016/j.neunet.2019.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 03/29/2019] [Accepted: 04/02/2019] [Indexed: 02/04/2023]
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41
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Patel JM, Swanson J, Ung K, Herman A, Hanson E, Ortiz-Guzman J, Selever J, Tong Q, Arenkiel BR. Sensory perception drives food avoidance through excitatory basal forebrain circuits. eLife 2019; 8:44548. [PMID: 31074744 PMCID: PMC6510534 DOI: 10.7554/elife.44548] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/26/2019] [Indexed: 12/14/2022] Open
Abstract
Appetite is driven by nutritional state, environmental cues, mood, and reward pathways. Environmental cues strongly influence feeding behavior, as they can dramatically induce or diminish the drive to consume food despite homeostatic state. Here, we have uncovered an excitatory neuronal population in the basal forebrain that is activated by food-odor related stimuli, and potently drives hypophagia. Notably, we found that the basal forebrain directly integrates environmental sensory cues to govern feeding behavior, and that basal forebrain signaling, mediated through projections to the lateral hypothalamus, promotes selective avoidance of food and food-related stimuli. Together, these findings reveal a novel role for the excitatory basal forebrain in regulating appetite suppression through food avoidance mechanisms, highlighting a key function for this structure as a potent integrator of sensory information towards governing consummatory behaviors.
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Affiliation(s)
- Jay M Patel
- Medical Scientist Training Program, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Jessica Swanson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kevin Ung
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Alexander Herman
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, United States
| | - Elizabeth Hanson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Joshua Ortiz-Guzman
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Jennifer Selever
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States
| | - Qingchun Tong
- Institute of Molecular Medicine, University of Texas Health Science Center, Houston, United States
| | - Benjamin R Arenkiel
- Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States
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42
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Mondragón-Rodríguez S, Gu N, Fasano C, Peña-Ortega F, Williams S. Functional Connectivity between Hippocampus and Lateral Septum is Affected in Very Young Alzheimer’s Transgenic Mouse Model. Neuroscience 2019; 401:96-105. [DOI: 10.1016/j.neuroscience.2018.12.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/20/2018] [Accepted: 12/22/2018] [Indexed: 12/29/2022]
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43
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Gq-Coupled Muscarinic Receptor Enhancement of KCNQ2/3 Channels and Activation of TRPC Channels in Multimodal Control of Excitability in Dentate Gyrus Granule Cells. J Neurosci 2018; 39:1566-1587. [PMID: 30593498 DOI: 10.1523/jneurosci.1781-18.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 12/21/2022] Open
Abstract
KCNQ (Kv7, "M-type") K+ channels and TRPC (transient receptor potential, "canonical") cation channels are coupled to neuronal discharge properties and are regulated via Gq/11-protein-mediated signals. Stimulation of Gq/11-coupled receptors both consumes phosphatidylinositol 4,5-bisphosphate (PIP2) via phosphalipase Cβ hydrolysis and stimulates PIP2 synthesis via rises in Ca2+ i and other signals. Using brain-slice electrophysiology and Ca2+ imaging from male and female mice, we characterized threshold K+ currents in dentate gyrus granule cells (DGGCs) and CA1 pyramidal cells, the effects of Gq/11-coupled muscarinic M1 acetylcholine (M1R) stimulation on M current and on neuronal discharge properties, and elucidated the intracellular signaling mechanisms involved. We observed disparate signaling cascades between DGGCs and CA1 neurons. DGGCs displayed M1R enhancement of M-current, rather than suppression, due to stimulation of PIP2 synthesis, which was paralleled by increased PIP2-gated G-protein coupled inwardly rectifying K+ currents as well. Deficiency of KCNQ2-containing M-channels ablated the M1R-induced enhancement of M-current in DGGCs. Simultaneously, M1R stimulation in DGGCs induced robust increases in [Ca2+]i, mostly due to TRPC currents, consistent with, and contributing to, neuronal depolarization and hyperexcitability. CA1 neurons did not display such multimodal signaling, but rather M current was suppressed by M1R stimulation in these cells, similar to the previously described actions of M1R stimulation on M-current in peripheral ganglia that mostly involves PIP2 depletion. Therefore, these results point to a pleiotropic network of cholinergic signals that direct cell-type-specific, precise control of hippocampal function with strong implications for hyperexcitability and epilepsy.SIGNIFICANCE STATEMENT At the neuronal membrane, protein signaling cascades consisting of ion channels and metabotropic receptors govern the electrical properties and neurotransmission of neuronal networks. Muscarinic acetylcholine receptors are G-protein-coupled metabotropic receptors that control the excitability of neurons through regulating ion channels, intracellular Ca2+ signals, and other second-messenger cascades. We have illuminated previously unknown actions of muscarinic stimulation on the excitability of hippocampal principal neurons that include M channels, TRPC (transient receptor potential, "canonical") cation channels, and powerful regulation of lipid metabolism. Our results show that these signaling pathways, and mechanisms of excitability, are starkly distinct between peripheral ganglia and brain, and even between different principal neurons in the hippocampus.
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44
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Skovgård K, Agerskov C, Kohlmeier KA, Herrik KF. The 5-HT3 receptor antagonist ondansetron potentiates the effects of the acetylcholinesterase inhibitor donepezil on neuronal network oscillations in the rat dorsal hippocampus. Neuropharmacology 2018; 143:130-142. [DOI: 10.1016/j.neuropharm.2018.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 11/24/2022]
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45
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Gu Y, Servello D, Han Z, Lalchandani RR, Ding JB, Huang K, Gu C. Balanced Activity between Kv3 and Nav Channels Determines Fast-Spiking in Mammalian Central Neurons. iScience 2018; 9:120-137. [PMID: 30390433 PMCID: PMC6218699 DOI: 10.1016/j.isci.2018.10.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/11/2018] [Accepted: 10/12/2018] [Indexed: 10/29/2022] Open
Abstract
Fast-spiking (FS) neurons can fire action potentials (APs) up to 1,000 Hz and play key roles in vital functions such as sound location, motor coordination, and cognition. Here we report that the concerted actions of Kv3 voltage-gated K+ (Kv) and Na+ (Nav) channels are sufficient and necessary for inducing and maintaining FS. Voltage-clamp analysis revealed a robust correlation between the Kv3/Nav current ratio and FS. Expressing Kv3 channels alone could convert ∼30%-60% slow-spiking (SS) neurons to FS in culture. In contrast, co-expression of either Nav1.2 or Nav1.6 together with Kv3.1 or Kv3.3, but not alone or with Kv1.2, converted SS to FS with 100% efficiency. Furthermore, RNA-sequencing-based genome-wide analysis revealed that the Kv3/Nav ratio and Kv3 expression levels strongly correlated with the maximal AP frequencies. Therefore, FS is established by the properly balanced activities of Kv3 and Nav channels and could be further fine-tuned by channel biophysical features and localization patterns.
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Affiliation(s)
- Yuanzheng Gu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, 182 Rightmire Hall, 1060 Carmack Road, Columbus, OH 43210, USA
| | - Dustin Servello
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Zhi Han
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; College of Software, Nankai University, Tianjin 300071, China; Regenstrief Institute, Indianapolis, IN 46202, USA
| | - Rupa R Lalchandani
- Department of Neurosurgery, and Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jun B Ding
- Department of Neurosurgery, and Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Kun Huang
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Regenstrief Institute, Indianapolis, IN 46202, USA; School of Biomedical Engineering, Shenzhen University, Shenzhen 518037, China
| | - Chen Gu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, 182 Rightmire Hall, 1060 Carmack Road, Columbus, OH 43210, USA; Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA.
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46
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Bortz DM, Grace AA. Medial septum activation produces opposite effects on dopamine neuron activity in the ventral tegmental area and substantia nigra in MAM vs. normal rats. NPJ SCHIZOPHRENIA 2018; 4:17. [PMID: 30177811 PMCID: PMC6120917 DOI: 10.1038/s41537-018-0059-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/30/2018] [Accepted: 08/06/2018] [Indexed: 11/08/2022]
Abstract
The medial septum (MS) differentially impacts midbrain dopamine (DA) neuron activity via the ventral hippocampus, a region implicated in DA-related disorders. However, whether MS regulation of ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) is disrupted in a developmental disruption model of schizophrenia is unknown. Male Sprague-Dawley rats were exposed at gestational day 17 to methylazoxymethanol (MAM) or saline. As adults, NMDA (0.75 µg/0.2 µL) was infused into the MS, and either DA neuron activity in the VTA and SNc (7-9 anesthetized rats per group) or amphetamine-induced hyperlocomotion (AIH, 11-13 rats per group) was measured. MS activation produced a 58% increase in the number of spontaneously active DA neurons in VTA and a 37% decrease in SNc in saline rats. However, MS activation produced opposite effects on DA population activity in MAM rats, decreasing VTA DA activity by 51% and increasing SNc DA activity by 47%. MS activation also increased AIH by 113% in MAM rats, opposite of what is seen in intact rats. The effect in behavioral output may be due to disrupted GABAergic regulation of SNc as bicuculline infusion into vSub, which selectively prevented the MS activation-induced decrease in SNc DA activity in intact rats, prevented the increase in AIH and SNc DA activity in MAM rats. These findings demonstrate that the regulation of midbrain DA neurons by the MS is disrupted in this well-validated animal model, suggesting that it could be a potential locus for pharmacological intervention in disorders such as schizophrenia.
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Affiliation(s)
- David M Bortz
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
| | - Anthony A Grace
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
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Solari N, Hangya B. Cholinergic modulation of spatial learning, memory and navigation. Eur J Neurosci 2018; 48:2199-2230. [PMID: 30055067 PMCID: PMC6174978 DOI: 10.1111/ejn.14089] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/25/2018] [Accepted: 07/23/2018] [Indexed: 01/02/2023]
Abstract
Spatial learning, including encoding and retrieval of spatial memories as well as holding spatial information in working memory generally serving navigation under a broad range of circumstances, relies on a network of structures. While central to this network are medial temporal lobe structures with a widely appreciated crucial function of the hippocampus, neocortical areas such as the posterior parietal cortex and the retrosplenial cortex also play essential roles. Since the hippocampus receives its main subcortical input from the medial septum of the basal forebrain (BF) cholinergic system, it is not surprising that the potential role of the septo-hippocampal pathway in spatial navigation has been investigated in many studies. Much less is known of the involvement in spatial cognition of the parallel projection system linking the posterior BF with neocortical areas. Here we review the current state of the art of the division of labour within this complex 'navigation system', with special focus on how subcortical cholinergic inputs may regulate various aspects of spatial learning, memory and navigation.
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Affiliation(s)
- Nicola Solari
- Lendület Laboratory of Systems NeuroscienceDepartment of Cellular and Network NeurobiologyInstitute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
| | - Balázs Hangya
- Lendület Laboratory of Systems NeuroscienceDepartment of Cellular and Network NeurobiologyInstitute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
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48
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Bortz DM, Grace AA. Medial septum differentially regulates dopamine neuron activity in the rat ventral tegmental area and substantia nigra via distinct pathways. Neuropsychopharmacology 2018; 43:2093-2100. [PMID: 29654260 PMCID: PMC6098086 DOI: 10.1038/s41386-018-0048-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/06/2018] [Accepted: 03/12/2018] [Indexed: 01/12/2023]
Abstract
The medial septum (MS) impacts hippocampal activity and the hippocampus, in turn, regulates midbrain dopamine (DA) neuron activity. However, it remains to be determined how MS activation impacts midbrain DA activity. This question was addressed by infusing NMDA (0.75 µg/0.2 µL) into the medial septum of anesthetized male Sprague-Dawley rats and recording dopamine neuron activity in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). MS activation increased (71%) the number of spontaneously active DA neurons in the VTA, and decreased (40%) the number of active DA neurons in the SNc. Effects in both the VTA and SNc required the ventral subiculum, but were differentially dependent on cholinergic and GABAergic mechanisms within the vSub and rostral and caudal subregions of the ventral pallidum, respectively. MS activation also decreased amphetamine-induced locomotor behavior, which was dependent on GABAergic inputs to the hippocampus. These findings demonstrate that the MS differentially regulates meso-striatal DA transmission via distinct pathways.
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Affiliation(s)
- David M. Bortz
- 0000 0004 1936 9000grid.21925.3dDepartments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Anthony A. Grace
- 0000 0004 1936 9000grid.21925.3dDepartments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, PA 15260 USA
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49
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Luquin E, Huerta I, Aymerich MS, Mengual E. Stereological Estimates of Glutamatergic, GABAergic, and Cholinergic Neurons in the Pedunculopontine and Laterodorsal Tegmental Nuclei in the Rat. Front Neuroanat 2018; 12:34. [PMID: 29867374 PMCID: PMC5958217 DOI: 10.3389/fnana.2018.00034] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Accepted: 04/16/2018] [Indexed: 01/29/2023] Open
Abstract
The pedunculopontine tegmental nucleus (PPN) and laterodorsal tegmental nucleus (LDT) are functionally associated brainstem structures implicated in behavioral state control and sensorimotor integration. The PPN is also involved in gait and posture, while the LDT plays a role in reward. Both nuclei comprise characteristic cholinergic neurons intermingled with glutamatergic and GABAergic cells whose absolute numbers in the rat have been only partly established. Here we sought to determine the complete phenotypical profile of each nucleus to investigate potential differences between them. Counts were obtained using stereological methods after the simultaneous visualization of cholinergic and either glutamatergic or GABAergic cells. The two isoforms of glutamic acid decarboxylase (GAD), GAD65 and GAD67, were separately analyzed. Dual in situ hybridization revealed coexpression of GAD65 and GAD67 mRNAs in ∼90% of GAD-positive cells in both nuclei; thus, the estimated mean numbers of (1) cholinergic, (2) glutamatergic, and (3) GABAergic cells in PPN and LDT, respectively, were (1) 3,360 and 3,650; (2) 5,910 and 5,190; and (3) 4,439 and 7,599. These data reveal significant differences between PPN and LDT in their relative phenotypical composition, which may underlie some of the functional differences observed between them. The estimation of glutamatergic cells was significantly higher in the caudal PPN, supporting the reported functional rostrocaudal segregation in this nucleus. Finally, a small subset of cholinergic neurons (8% in PPN and 5% in LDT) also expressed the glutamatergic marker Vglut2, providing anatomical evidence for a potential corelease of transmitters at specific target areas.
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Affiliation(s)
- Esther Luquin
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Ibone Huerta
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - María S Aymerich
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain.,Department of Biochemistry and Genetics, School of Science, University of Navarra, Pamplona, Spain
| | - Elisa Mengual
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain.,Anatomy Department, School of Medicine, University of Navarra, Pamplona, Spain
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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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