1
|
Mocellin P, Barnstedt O, Luxem K, Kaneko H, Vieweg S, Henschke JU, Dalügge D, Fuhrmann F, Karpova A, Pakan JMP, Kreutz MR, Mikulovic S, Remy S. A septal-ventral tegmental area circuit drives exploratory behavior. Neuron 2024; 112:1020-1032.e7. [PMID: 38266645 DOI: 10.1016/j.neuron.2023.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/10/2023] [Accepted: 12/20/2023] [Indexed: 01/26/2024]
Abstract
To survive, animals need to balance their exploratory drive with their need for safety. Subcortical circuits play an important role in initiating and modulating movement based on external demands and the internal state of the animal; however, how motivation and onset of locomotion are regulated remain largely unresolved. Here, we show that a glutamatergic pathway from the medial septum and diagonal band of Broca (MSDB) to the ventral tegmental area (VTA) controls exploratory locomotor behavior in mice. Using a self-supervised machine learning approach, we found an overrepresentation of exploratory actions, such as sniffing, whisking, and rearing, when this projection is optogenetically activated. Mechanistically, this role relies on glutamatergic MSDB projections that monosynaptically target a subset of both glutamatergic and dopaminergic VTA neurons. Taken together, we identified a glutamatergic basal forebrain to midbrain circuit that initiates locomotor activity and contributes to the expression of exploration-associated behavior.
Collapse
Affiliation(s)
- Petra Mocellin
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; International Max Planck Research School for Brain and Behavior (IMPRS), Bonn 53175, Germany.
| | - Oliver Barnstedt
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Kevin Luxem
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Hiroshi Kaneko
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Silvia Vieweg
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Julia U Henschke
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Dennis Dalügge
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; International Max Planck Research School for Brain and Behavior (IMPRS), Bonn 53175, Germany
| | - Falko Fuhrmann
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Anna Karpova
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg 39106, Germany
| | - Janelle M P Pakan
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; German Center for Neurodegenerative Diseases (DZNE), Magdeburg 39120, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg 39106, Germany
| | - Michael R Kreutz
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; German Center for Neurodegenerative Diseases (DZNE), Magdeburg 39120, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg 39106, Germany; German Center for Mental Health (DZPG), Magdeburg 39106, Germany
| | - Sanja Mikulovic
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg 39106, Germany; German Center for Mental Health (DZPG), Magdeburg 39106, Germany
| | - Stefan Remy
- Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; German Center for Neurodegenerative Diseases (DZNE), Magdeburg 39120, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg 39106, Germany; German Center for Mental Health (DZPG), Magdeburg 39106, Germany.
| |
Collapse
|
2
|
Bendrath SC, Cook CA, Knapp DJ, Thiele TE. Orexinergic lateral hypothalamus (LH) projections to medial septum (MS) modulate ethanol-induced sedation in male and female mice and binge-like ethanol drinking in male mice only. Alcohol 2024; 115:13-22. [PMID: 37717641 PMCID: PMC10922035 DOI: 10.1016/j.alcohol.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/21/2023] [Accepted: 09/12/2023] [Indexed: 09/19/2023]
Abstract
Orexin in both the lateral hypothalamus (LH) and medial septum (MS) is involved in sleep- and consciousness-related conditions. Since orexin modulates the intoxicating as well as rewarding effects of ethanol, this study focused on the role of orexin-projecting neurons from the LH to the MS, and this neurocircuit's role in mediating the sedative effects of alcohol. Drinking-in-the-Dark (DID) behavior was also assessed as a measure of the role of the LH-MS pathway in modulating binge-like ethanol intake, with a particular focus on sex differences in both behavioral paradigms. Male and female Hcrt-ires-cre mice received cannulation in the MS, while the LH was injected bilaterally with cre-dependent excitatory (Gq) Designer Receptor Exclusively Activated by Designer Drug (DREADD), inhibitory (Gi) DREADD or control virus. All subjects received a 3.75 g/kg dose of 20 % ethanol intraperitoneally and the sedative effect was assessed by the loss of righting reflex (LORR). After behavioral testing, brains were used for c-Fos immunohistochemistry analyses. A separate cohort of mice was used for a 2-week DID protocol using excitatory (Gq) DREADD and control virus. Gq DREADD-induced activation of the orexin neurocircuitry from the LH to the MS significantly reduced sedation time in both female and male mice. Furthermore, CNO treatment failed to alter ethanol sedation times in both animals expressing Gi DREADDs and control virus. There were no significant differences in blood ethanol concentrations (BECs) in any experimental group, suggesting that changes in sedation were not due to treatment-induced alterations of ethanol metabolism. Interestingly, in the DID study, only male mice decreased their ethanol consumption when Gq DREADDs were activated. These results provide novel evidence on the role played by this orexinergic LH to MS circuit on the sedative effects of ethanol and ethanol consumption in a sex-dependent manner. Thus, the MS should be considered further as a novel sexually dimorphic target.
Collapse
Affiliation(s)
- Sophie C Bendrath
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3270, United States
| | - Cory A Cook
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3270, United States
| | - Darin J Knapp
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7178, United States
| | - Todd E Thiele
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3270, United States; Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7178, United States.
| |
Collapse
|
3
|
Vardalakis N, Aussel A, Rougier NP, Wagner FB. A dynamical computational model of theta generation in hippocampal circuits to study theta-gamma oscillations during neurostimulation. eLife 2024; 12:RP87356. [PMID: 38354040 PMCID: PMC10942594 DOI: 10.7554/elife.87356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Neurostimulation of the hippocampal formation has shown promising results for modulating memory but the underlying mechanisms remain unclear. In particular, the effects on hippocampal theta-nested gamma oscillations and theta phase reset, which are both crucial for memory processes, are unknown. Moreover, these effects cannot be investigated using current computational models, which consider theta oscillations with a fixed amplitude and phase velocity. Here, we developed a novel computational model that includes the medial septum, represented as a set of abstract Kuramoto oscillators producing a dynamical theta rhythm with phase reset, and the hippocampal formation, composed of biophysically realistic neurons and able to generate theta-nested gamma oscillations under theta drive. We showed that, for theta inputs just below the threshold to induce self-sustained theta-nested gamma oscillations, a single stimulation pulse could switch the network behavior from non-oscillatory to a state producing sustained oscillations. Next, we demonstrated that, for a weaker theta input, pulse train stimulation at the theta frequency could transiently restore seemingly physiological oscillations. Importantly, the presence of phase reset influenced whether these two effects depended on the phase at which stimulation onset was delivered, which has practical implications for designing neurostimulation protocols that are triggered by the phase of ongoing theta oscillations. This novel model opens new avenues for studying the effects of neurostimulation on the hippocampal formation. Furthermore, our hybrid approach that combines different levels of abstraction could be extended in future work to other neural circuits that produce dynamical brain rhythms.
Collapse
Affiliation(s)
- Nikolaos Vardalakis
- University of Bordeaux, CNRS, IMNBordeauxFrance
- University of Bordeaux, INRIA, IMNBordeauxFrance
| | - Amélie Aussel
- University of Bordeaux, CNRS, IMNBordeauxFrance
- University of Bordeaux, INRIA, IMNBordeauxFrance
- University of Bordeaux, CNRS, Bordeaux INPTalenceFrance
| | - Nicolas P Rougier
- University of Bordeaux, CNRS, IMNBordeauxFrance
- University of Bordeaux, INRIA, IMNBordeauxFrance
- University of Bordeaux, CNRS, Bordeaux INPTalenceFrance
| | | |
Collapse
|
4
|
Cassity S, Choi IJ, Gregory BH, Igbasanmi AM, Bickford SC, Moore KT, Seraiah AE, Layfield D, Newman EL. Cholinergic modulation of rearing in rats performing a spatial memory task. Eur J Neurosci 2024. [PMID: 38258622 DOI: 10.1111/ejn.16248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/04/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024]
Abstract
Spatial memory encoding depends in part on cholinergic modulation. How acetylcholine supports spatial memory encoding is not well understood. Prior studies indicate that acetylcholine release is correlated with exploration, including epochs of rearing onto hind legs. Here, to test whether elevated cholinergic tone increases the probability of rearing, we tracked rearing frequency and duration while optogenetically modulating the activity of choline acetyltransferase containing (i.e., acetylcholine producing) neurons of the medial septum in rats performing a spatial working memory task (n = 17 rats). The cholinergic neurons were optogenetically inhibited using halorhodopsin for the duration that rats occupied two of the four open arms during the study phase of an 8-arm radial arm maze win-shift task. Comparing rats' behaviour in the two arm types showed that rearing frequency was not changed, but the average duration of rearing epochs became significantly longer. This effect on rearing was observed during optogenetic inhibition but not during sham inhibition or in rats that received infusions of a fluorescent reporter virus (i.e., without halorhodopsin; n = 6 rats). Optogenetic inhibition of cholinergic neurons during the pretrial waiting phase had no significant effect on rearing, indicating a context-specificity of the observed effects. These results are significant in that they indicate that cholinergic neuron activity in the medial septum is correlated with rearing not because it motivates an exploratory state but because it contributes to the processing of information acquired while rearing.
Collapse
Affiliation(s)
- Skylar Cassity
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
- Program in Neuroscience, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Irene Jungyeon Choi
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Billy Howard Gregory
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Adeleke Malik Igbasanmi
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Sarah Cristi Bickford
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Kiara Tyanni Moore
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
| | | | - Dylan Layfield
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
- Intelligent Systems Engineering, Luddy School of Informatics Computing and Engineering, University Bloomington, Bloomington, Indiana, USA
| | - Ehren Lee Newman
- Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University Bloomington, Bloomington, Indiana, USA
- Intelligent Systems Engineering, Luddy School of Informatics Computing and Engineering, University Bloomington, Bloomington, Indiana, USA
| |
Collapse
|
5
|
Carvalho R, Lukoyanova AN, Casalta-Lopes J, Lukoyanov NV, Soares JI. Plastic rearrangement of basal forebrain parvalbumin-immunoreactive neurons in the kainite model of epilepsy. AIMS Neurosci 2023; 10:300-314. [PMID: 38188006 PMCID: PMC10767069 DOI: 10.3934/neuroscience.2023023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/21/2023] [Accepted: 10/27/2023] [Indexed: 01/09/2024] Open
Abstract
Temporal lobe epilepsy (TLE) is the most prevalent form of epilepsy, through the neuronal mechanisms of this syndrome remain elusive. In addition to the temporal lobe structures, it was found that the basal forebrain cholinergic cells are also involved in epileptogenesis. However, little is known about the involvement of the basal forebrain GABAergic neurons in epilepsy; despite this, they largely project to the temporal lobe and are crucial for the regulation of the hippocampal circuitry. In this study, we assessed epilepsy-induced changes in parvalbumin (PARV) immunoreactive neurons of the medial septum (MS) and of the magnocellular preoptic nucleus (MCPO) using the kainic acid (KA) model in rats. In addition, we estimated the respective changes in the cholinergic varicosities in the MS, where we observed a significant reduction in the PARV cell number (12849 ± 2715 vs. 9372 ± 1336, p = .029) and density (16.2 ± 2.62 vs. 10.5 ± 1.00 per .001 mm3, p =.001), and an increase in the density of cholinergic varicosities (47.9 ± 11.1 vs. 69.4 ± 17.8 per 30,000 µm2, p =.036) in KA-treated animals. In the MCPO, these animals showed a significant increase in somatic volume (827.9 ± 235.2 µm3 vs. 469.9 ± 79.6 µm3, p = .012) and total cell number (2268.6 ± 707.1 vs. 1362.4 ± 262.0, p =.028). These results show that the basal forebrain GABAergic cell populations undergo numerical and morphological changes in epileptic animals, which may contribute to an increased vulnerability of brain circuits to epilepsy and epilepsy-related functional impairments.
Collapse
Affiliation(s)
- Ruben Carvalho
- Master in Neurobiology, Faculty of Medicine, University of Porto, Porto, Portugal
- Neuronal Networks Group, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
- Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Alisa N. Lukoyanova
- Neuronal Networks Group, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
| | - João Casalta-Lopes
- Department of Basic Sciences, Polytechnic Institute of Coimbra, Coimbra Health School, Coimbra, Portugal
- Life and Health Sciences Research Institute / School of Medicine - University of Minho, Braga, Portugal
- Department of Radiotherapy, University Hospital Center of São João, Porto, Portugal
| | - Nikolay V. Lukoyanov
- Neuronal Networks Group, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
- Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Joana Isabel Soares
- Neuronal Networks Group, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
- Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
- Department of Basic Sciences, Polytechnic Institute of Coimbra, Coimbra Health School, Coimbra, Portugal
| |
Collapse
|
6
|
Robinson JC, Wilmot JH, Hasselmo ME. Septo-hippocampal dynamics and the encoding of space and time. Trends Neurosci 2023; 46:712-725. [PMID: 37479632 PMCID: PMC10538955 DOI: 10.1016/j.tins.2023.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/12/2023] [Accepted: 06/27/2023] [Indexed: 07/23/2023]
Abstract
Encoding an event in memory requires neural activity to represent multiple dimensions of behavioral experience in space and time. Recent experiments have explored the influence of neural dynamics regulated by the medial septum on the functional encoding of space and time by neurons in the hippocampus and associated structures. This review addresses these dynamics, focusing on the role of theta rhythm, the differential effects of septal inactivation and activation on the functional coding of space and time by individual neurons, and the influence on phase coding that appears as phase precession. We also discuss data indicating that theta rhythm plays a role in timing the internal dynamics of memory encoding and retrieval, as well as the behavioral influences of these neuronal manipulations with regard to memory function.
Collapse
Affiliation(s)
- Jennifer C Robinson
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA.
| | - Jacob H Wilmot
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA.
| | - Michael E Hasselmo
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA.
| |
Collapse
|
7
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
Affiliation(s)
| | | | - Sylvain Williams
- Department of Psychiatry, Douglas Mental Health Research Institute, McGill University, Montreal, QC, Canada
| |
Collapse
|
8
|
Dobryakova YV, Gerasimov K, Spivak YS, Korotkova T, Koryagina A, Deryabina A, Markevich VA, Bolshakov AP. The Induction of Long-Term Potentiation by Medial Septum Activation under Urethane Anesthesia Can Alter Gene Expression in the Hippocampus. Int J Mol Sci 2023; 24:12970. [PMID: 37629149 PMCID: PMC10454684 DOI: 10.3390/ijms241612970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/07/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
We studied changes in the expression of early genes in hippocampal cells in response to stimulation of the dorsal medial septal area (dMSA), leading to long-term potentiation in the hippocampus. Rats under urethane anesthesia were implanted with stimulating electrodes in the ventral hippocampal commissure and dMSA and a recording electrode in the CA1 area of the hippocampus. We found that high-frequency stimulation (HFS) of the dMSA led to the induction of long-term potentiation in the synapses formed by the ventral hippocampal commissure on the hippocampal CA1 neurons. One hour after dMSA HFS, we collected the dorsal and ventral hippocampi on both the ipsilateral (damaged by the implanted electrode) and contralateral (intact) sides and analyzed the expression of genes by qPCR. The dMSA HFS led to an increase in the expression of bdnf and cyr61 in the ipsilateral hippocampi and egr1 in the ventral contralateral hippocampus. Thus, dMSA HFS under the conditions of degeneration of the cholinergic neurons in the medial septal area prevented the described increase in gene expression. The changes in cyr61 expression appeared to be dependent on the muscarinic M1 receptors. Our data suggest that the induction of long-term potentiation by dMSA activation enhances the expression of select early genes in the hippocampus.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Alexey P. Bolshakov
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 117485 Moscow, Russia (K.G.)
| |
Collapse
|
9
|
Li Y, Zhao L, Zhang K, Shen M, Li Y, Yu Y, Yu J, Feng J, Xie K, Yu Y. Neurometabolic and structural alterations of medial septum and hippocampal CA1 in a model of post-operative sleep fragmentation in aged mice: a study combining 1H-MRS and DTI. Front Cell Neurosci 2023; 17:1160761. [PMID: 37333891 PMCID: PMC10272368 DOI: 10.3389/fncel.2023.1160761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023] Open
Abstract
Post-operative sleep disturbance is a common feature of elderly surgical patients, and sleep fragmentation (SF) is closely related to post-operative cognitive dysfunction (POCD). SF is characterized by sleep interruption, increased number of awakenings and sleep structure destruction, similar to obstructive sleep apnea (OSA). Research shows that sleep interruption can change neurotransmitter metabolism and structural connectivity in sleep and cognitive brain regions, of which the medial septum and hippocampal CA1 are key brain regions connecting sleep and cognitive processes. Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive method for the evaluation of neurometabolic abnormalities. Diffusion tensor imaging (DTI) realizes the observation of structural integrity and connectivity of brain regions of interest in vivo. However, it is unclear whether post-operative SF induces harmful changes in neurotransmitters and structures of the key brain regions and their contribution to POCD. In this study, we evaluated the effects of post-operative SF on neurotransmitter metabolism and structural integrity of medial septum and hippocampal CA1 in aged C57BL/6J male mice. The animals received a 24-h SF procedure after isoflurane anesthesia and right carotid artery exposure surgery. 1H-MRS results showed after post-operative SF, the glutamate (Glu)/creatine (Cr) and glutamate + glutamine (Glx)/Cr ratios increased in the medial septum and hippocampal CA1, while the NAA/Cr ratio decreased in the hippocampal CA1. DTI results showed post-operative SF decreased the fractional anisotropy (FA) of white matter fibers in the hippocampal CA1, while the medial septum was not affected. Moreover, post-operative SF aggravated subsequent Y-maze and novel object recognition performances accompanied by abnormal enhancement of glutamatergic metabolism signal. This study suggests that 24-h SF induces hyperglutamate metabolism level and microstructural connectivity damage in sleep and cognitive brain regions in aged mice, which may be involved in the pathophysiological process of POCD.
Collapse
Affiliation(s)
- Yun Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Lina Zhao
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Kai Zhang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Mengxi Shen
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Yize Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Yang Yu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Jiafeng Yu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Jingyu Feng
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Keliang Xie
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Yonghao Yu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Research Institute of Anesthesiology, Tianjin, China
| |
Collapse
|
10
|
Alldred MJ, Pidikiti H, Heguy A, Roussos P, Ginsberg SD. Basal forebrain cholinergic neurons are vulnerable in a mouse model of Down syndrome and their molecular fingerprint is rescued by maternal choline supplementation. FASEB J 2023; 37:e22944. [PMID: 37191946 DOI: 10.1096/fj.202202111rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/12/2023] [Accepted: 04/18/2023] [Indexed: 05/17/2023]
Abstract
Basal forebrain cholinergic neuron (BFCN) degeneration is a hallmark of Down syndrome (DS) and Alzheimer's disease (AD). Current therapeutics in these disorders have been unsuccessful in slowing disease progression, likely due to poorly understood complex pathological interactions and dysregulated pathways. The Ts65Dn trisomic mouse model recapitulates both cognitive and morphological deficits of DS and AD, including BFCN degeneration and has shown lifelong behavioral changes due to maternal choline supplementation (MCS). To test the impact of MCS on trisomic BFCNs, we performed laser capture microdissection to individually isolate choline acetyltransferase-immunopositive neurons in Ts65Dn and disomic littermates, in conjunction with MCS at the onset of BFCN degeneration. We utilized single population RNA sequencing (RNA-seq) to interrogate transcriptomic changes within medial septal nucleus (MSN) BFCNs. Leveraging multiple bioinformatic analysis programs on differentially expressed genes (DEGs) by genotype and diet, we identified key canonical pathways and altered physiological functions within Ts65Dn MSN BFCNs, which were attenuated by MCS in trisomic offspring, including the cholinergic, glutamatergic and GABAergic pathways. We linked differential gene expression bioinformatically to multiple neurological functions, including motor dysfunction/movement disorder, early onset neurological disease, ataxia and cognitive impairment via Ingenuity Pathway Analysis. DEGs within these identified pathways may underlie aberrant behavior in the DS mice, with MCS attenuating the underlying gene expression changes. We propose MCS ameliorates aberrant BFCN gene expression within the septohippocampal circuit of trisomic mice through normalization of principally the cholinergic, glutamatergic, and GABAergic signaling pathways, resulting in attenuation of underlying neurological disease functions.
Collapse
Affiliation(s)
- Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York, USA
| | - Harshitha Pidikiti
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA
| | - Adriana Heguy
- Genome Technology Center, New York University Grossman School of Medicine, New York, New York, USA
| | - Panos Roussos
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- The Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York, USA
- Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, New York, USA
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, New York, USA
| |
Collapse
|
11
|
Bortz DM, Feistritzer CM, Grace AA. Medial prefrontal cortex to medial septum pathway activation improves cognitive flexibility in rats. Int J Neuropsychopharmacol 2023:7173592. [PMID: 37207293 DOI: 10.1093/ijnp/pyad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND The medial prefrontal cortex (mPFC) is necessary for cognitive flexibility and projects to medial septum (MS). MS activation improves strategy switching, a common measure of cognitive flexibility, via its ability to regulate midbrain dopamine (DA) neuron population activity. We hypothesized that the mPFC to MS pathway may be the mechanism by which the MS regulates strategy switching and DA neuron population activity. METHODS Male and female rats learned a complex discrimination strategy across two different training time points: a constant length (10 days) and a variable length that coincided with each rat meeting an acquisition-level performance threshold (males-5.3 + 0.3 days, females-3.8 + 0.3 days). We then chemogenetically activated or inhibited the mPFC-MS pathway and measured each rat's ability to inhibit the prior learned discrimination strategy and switch to a prior ignored discrimination strategy (strategy switching). RESULTS Activation of the mPFC-MS pathway improved strategy switching after 10 days of training in both sexes, while inhibition of the pathway had little to no effect on strategy switching. Neither activation nor inhibition of the mPFC-MS pathway affected strategy switching following the acquisition-level performance threshold. Activation, but not inhibiton, of the mPFC-MS pathway bidirectionally regulated DA activity in ventral tegmental area and substantia nigra pars compacta, similar to MS activation. CONCLUSIONS This study presents a top-down circuit from the prefrontal cortex to the midbrain, with the MS being a critical contributor, by which DA activity can be manipulated to promote flexible behavior.
Collapse
Affiliation(s)
- David M Bortz
- Department of Neuroscience, Psychiatry, and Psychology, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA
| | - Catalina M Feistritzer
- Department of Neuroscience, Psychiatry, and Psychology, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA
| | - Anthony A Grace
- Department of Neuroscience, Psychiatry, and Psychology, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA
| |
Collapse
|
12
|
Fan BQ, Xia JM, Chen DD, Feng LL, Ding JH, Li SS, Li WX, Han Y. Medial septum glutamatergic neurons modulate nociception in chronic neuropathic pain via projections to lateral hypothalamus. Front Pharmacol 2023; 14:1171665. [PMID: 37266154 PMCID: PMC10229799 DOI: 10.3389/fphar.2023.1171665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/09/2023] [Indexed: 06/03/2023] Open
Abstract
The medial septum (MS) contributes in pain processing and regulation, especially concerning persistent nociception. However, the role of MS glutamatergic neurons in pain and the underlying neural circuit mechanisms in pain remain poorly understood. In this study, chronic constrictive injury of the sciatic nerve (CCI) surgery was performed to induce thermal and mechanical hyperalgesia in mice. The chemogenetic activation of MS glutamatergic neurons decreased pain thresholds in naïve mice. In contrast, inhibition or ablation of these neurons has improved nociception thresholds in naïve mice and relieved thermal and mechanical hyperalgesia in CCI mice. Anterograde viral tracing revealed that MS glutamatergic neurons had projections to the lateral hypothalamus (LH) and supramammillary nucleus (SuM). We further demonstrated that MS glutamatergic neurons regulate pain thresholds by projecting to LH but not SuM, because the inhibition of MS-LH glutamatergic projections suppressed pain thresholds in CCI and naïve mice, yet, optogenetic activation or inhibition of MS-SuM glutamatergic projections had no effect on pain thresholds in naïve mice. In conclusion, our results reveal that MS glutamatergic neurons play a significant role in regulating pain perception and decipher that MS glutamatergic neurons modulate nociception via projections to LH.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Yuan Han
- *Correspondence: Yuan Han, ; Wen-Xian Li,
| |
Collapse
|
13
|
Kniffin A, Bangasser DA, Parikh V. Septohippocampal cholinergic system at the intersection of stress and cognition: Current trends and translational implications. Eur J Neurosci 2023:10.1111/ejn.15999. [PMID: 37118907 PMCID: PMC10875782 DOI: 10.1111/ejn.15999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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.
Collapse
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
| |
Collapse
|
14
|
Lévesque M, Wang S, Etter G, Williams S, Avoli M. Optogenetic activation of septal inhibitory cells abates focal seizures. J Neurophysiol 2023; 129:1218-1223. [PMID: 37073973 DOI: 10.1152/jn.00111.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023] Open
Abstract
Emerging evidence suggest that the medial septum can control seizures occurring in focal epileptic disorders, thus representing a therapeutic target. Therefore, we investigated whether continuous optogenetic activation of inhibitory parvalbumin-positive (PV) interneurons in the medial septum can reduce the occurrence of spontaneous seizures in the pilocarpine model of mesial temporal lobe epilepsy (MTLE). Light pulses (450 nm, 25 mW, 20 ms pulse duration) were delivered at 0.5 Hz (5 min ON, 10 min OFF), with a laser diode fiber light source between day 8 and 12 after status epilepticus (SE) in PV-ChR2 mice (n = 8). Seizure rates were significantly lower during time-periods of optogenetic stimulation (day 8-12) compared to before implementa-tion of optogenetics (day 4-7) (p < 0.05). Moreover, between day 13 and 21 after SE, seizure rates were still significantly lower compared to before optogenetic stimulation (i.e., between day 4 and 7) (p < 0.05). No seizures were recorded between day 10 and 12 in all animals, and no seizures occurred up to three days after the end of optogenetic stimulation (day 13-15). Our findings indicate that activation of PV-positive interneurons in the medial septum abates seizures in the pilocarpine model of MTLE. Moreover, the persisting anti-ictogenic effects suggests that stimulation of the medial septum could alter the progression of MTLE.
Collapse
Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery and Department of Physiology, McGill University Montreal, Quebec, Canada
| | - Siyan Wang
- Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery and Department of Physiology, McGill University Montreal, Quebec, Canada
| | - Guillaume Etter
- Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Massimo Avoli
- Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery and Department of Physiology, McGill University Montreal, Quebec, Canada
| |
Collapse
|
15
|
Wen YJ, Yang WJ, Guo CN, Qiu MH, Kroeger D, Niu JG, Zhan SQ, Yang XF, Gisabella B, Vetrivelan R, Lu J. Pontine control of rapid eye movement sleep and fear memory. CNS Neurosci Ther 2023; 29:1602-1614. [PMID: 36794544 PMCID: PMC10173714 DOI: 10.1111/cns.14123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 02/17/2023] Open
Abstract
AIMS We often experience dreams of strong irrational and negative emotional contents with postural muscle paralysis during rapid eye movement (REM) sleep, but how REM sleep is generated and its function remain unclear. In this study, we investigate whether the dorsal pontine sub-laterodorsal tegmental nucleus (SLD) is necessary and sufficient for REM sleep and whether REM sleep elimination alters fear memory. METHODS To investigate whether activation of SLD neurons is sufficient for REM sleep induction, we expressed channelrhodopsin-2 (ChR2) in SLD neurons by bilaterally injecting AAV1-hSyn-ChR2-YFP in rats. We next selectively ablated either glutamatergic or GABAergic neurons from the SLD in mice in order to identify the neuronal subset crucial for REM sleep. We finally investigated the role of REM sleep in consolidation of fear memory using rat model with complete SLD lesions. RESULTS We demonstrate the sufficiency of the SLD for REM sleep by showing that photo-activation of ChR2 transfected SLD neurons selectively promotes transitions from non-REM (NREM) sleep to REM sleep in rats. Diphtheria toxin-A (DTA) induced lesions of the SLD in rats or specific deletion of SLD glutamatergic neurons but not GABAergic neurons in mice completely abolish REM sleep, demonstrating the necessity of SLD glutamatergic neurons for REM sleep. We then show that REM sleep elimination by SLD lesions in rats significantly enhances contextual and cued fear memory consolidation by 2.5 and 1.0 folds, respectively, for at least 9 months. Conversely, fear conditioning and fear memory trigger doubled amounts of REM sleep in the following night, and chemo-activation of SLD neurons projecting to the medial septum (MS) selectively enhances hippocampal theta activity in REM sleep; this stimulation immediately after fear acquisition reduces contextual and cued fear memory consolidation by 60% and 30%, respectively. CONCLUSION SLD glutamatergic neurons generate REM sleep and REM sleep and SLD via the hippocampus particularly down-regulate contextual fear memory.
Collapse
Affiliation(s)
- Yu Jun Wen
- Ningxia Key Laboratory of Craniocerebral Diseases, Department of Anatomy, Histology and Embryology, School of Basic Medicine, Ningxia Medical University, Yinchuan, Ningxia, China.,Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Wen Jia Yang
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Shanghai Yueyang Integrated Medicine Hospital, Shanghai, China
| | - Chun Ni Guo
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurology, Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Mei Hong Qiu
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurobiology, School of Basic Medical Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Daniel Kroeger
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Jian Guo Niu
- Ningxia Key Laboratory of Craniocerebral Diseases, Department of Anatomy, Histology and Embryology, School of Basic Medicine, Ningxia Medical University, Yinchuan, Ningxia, China.,Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Shu Qin Zhan
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xi Fei Yang
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Shenzhen Center for Disease Control and Prevention, Shenzhen, Guangdong, China
| | - Barbara Gisabella
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Ramalingam Vetrivelan
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Jun Lu
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Stroke Center, Department of Neurology, 1st Hospital of Jilin University, Changchun, Jilin, China
| |
Collapse
|
16
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
|
17
|
Li X, Yu H, Zhang B, Li L, Chen W, Yu Q, Huang X, Ke X, Wang Y, Jing W, Du H, Li H, Zhang T, Liu L, Zhu LQ, Lu Y. Molecularly defined and functionally distinct cholinergic subnetworks. Neuron 2022; 110:3774-3788.e7. [PMID: 36130594 DOI: 10.1016/j.neuron.2022.08.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/27/2022] [Accepted: 08/23/2022] [Indexed: 12/15/2022]
Abstract
Cholinergic neurons in the medial septum (MS) constitute a major source of cholinergic input to the forebrain and modulate diverse functions, including sensory processing, memory, and attention. Most studies to date have treated cholinergic neurons as a single population; as such, the organizational principles underling their functional diversity remain unknown. Here, we identified two subsets (D28K+ versus D28K-) of cholinergic neurons that are topographically segregated in mice, Macaca fascicularis, and humans. These cholinergic subpopulations possess unique electrophysiological signatures, express mutually exclusive marker genes (kcnh1 and aifm3 versus cacna1h and gga3), and make differential connections with physiologically distinct neuronal classes in the hippocampus to form two structurally defined and functionally distinct circuits. Gain- and loss-of-function studies on these circuits revealed their differential roles in modulation of anxiety-like behavior and spatial memory. These results provide a molecular and circuitry-based theory for how cholinergic neurons contribute to their diverse behavioral functions.
Collapse
Affiliation(s)
- Xinyan Li
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hongyan Yu
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Bing Zhang
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lanfang Li
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wenting Chen
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Quntao Yu
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xian Huang
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiao Ke
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yunyun Wang
- Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wei Jing
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Huiyun Du
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hao Li
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tongmei Zhang
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Liang Liu
- Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ling-Qiang Zhu
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Youming Lu
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4030030, China; Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| |
Collapse
|
18
|
Kopsick JD, Hartzell K, Lazaro H, Nambiar P, Hasselmo ME, Dannenberg H. Temporal dynamics of cholinergic activity in the septo-hippocampal system. Front Neural Circuits 2022; 16:957441. [PMID: 36092276 PMCID: PMC9452968 DOI: 10.3389/fncir.2022.957441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Cholinergic projection neurons in the medial septum and diagonal band of Broca are the major source of cholinergic modulation of hippocampal circuit functions that support neural coding of location and running speed. Changes in cholinergic modulation are known to correlate with changes in brain states, cognitive functions, and behavior. However, whether cholinergic modulation can change fast enough to serve as a potential speed signal in hippocampal and parahippocampal cortices and whether the temporal dynamics in such a signal depend on the presence of visual cues remain unknown. In this study, we use a fiber-photometric approach to quantify the temporal dynamics of cholinergic activity in freely moving mice as a function of the animal's movement speed and visual cues. We show that the population activity of cholinergic neurons in the medial septum and diagonal band of Broca changes fast enough to be aligned well with changes in the animal's running speed and is strongly and linearly correlated to the logarithm of the animal's running speed. Intriguingly, the cholinergic modulation remains strongly and linearly correlated to the speed of the animal's neck movements during periods of stationary activity. Furthermore, we show that cholinergic modulation is unaltered during darkness. Lastly, we identify rearing, a stereotypic behavior where the mouse stands on its hindlimbs to scan the environment from an elevated perspective, is associated with higher cholinergic activity than expected from neck movements on the horizontal plane alone. Taken together, these data show that temporal dynamics in the cholinergic modulation of hippocampal circuits are fast enough to provide a potential running speed signal in real-time. Moreover, the data show that cholinergic modulation is primarily a function of the logarithm of the animal's movement speed, both during locomotion and during stationary activity, with no significant interaction with visual inputs. These data advance our understanding of temporal dynamics in cholinergic modulation of hippocampal circuits and their functions in the context of neural coding of location and running speed.
Collapse
Affiliation(s)
- Jeffrey D. Kopsick
- Department of Bioengineering, George Mason University, Fairfax, VA, United States,Interdisciplinary Program for Neuroscience, George Mason University, Fairfax, VA, United States
| | - Kyle Hartzell
- Department of Bioengineering, George Mason University, Fairfax, VA, United States
| | - Hallie Lazaro
- Center for Systems Neuroscience, Boston University, Boston, MA, United States,Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Pranav Nambiar
- Center for Systems Neuroscience, Boston University, Boston, MA, United States,Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Michael E. Hasselmo
- Center for Systems Neuroscience, Boston University, Boston, MA, United States,Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Holger Dannenberg
- Department of Bioengineering, George Mason University, Fairfax, VA, United States,Interdisciplinary Program for Neuroscience, George Mason University, Fairfax, VA, United States,*Correspondence: Holger Dannenberg,
| |
Collapse
|
19
|
Kocsis B, Martínez-Bellver S, Fiáth R, Domonkos A, Sviatkó K, Schlingloff D, Barthó P, Freund TF, Ulbert I, Káli S, Varga V, Hangya B. 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] [What about the content of this article? (0)] [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.
Collapse
|
20
|
Mu R, Tang S, Han X, Wang H, Yuan D, Zhao J, Long Y, Hong H. A cholinergic medial septum input to medial habenula mediates generalization formation and extinction of visual aversion. Cell Rep 2022; 39:110882. [PMID: 35649349 DOI: 10.1016/j.celrep.2022.110882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 12/07/2021] [Accepted: 05/06/2022] [Indexed: 12/28/2022] Open
Abstract
Generalization of visual aversion is a critical function of the brain that supports survival, but the underlying neurobiological mechanisms are unclear. We establish a rapid generalization procedure for inducing visual aversion by dynamic stripe images. By using fiber photometry, apoptosis, chemogenetic and optogenetic techniques, and behavioral tests, we find that decreased cholinergic neurons' activity in the medial septum (MS) leads to generalization loss of visual aversion. Strikingly, we identify a projection from MS cholinergic neurons to the medial habenula (MHb) and find that inhibition of the MS→MHb cholinergic circuit disrupts aversion-generalization formation while its continuous activation disrupts subsequent extinction. Further studies show that MS→MHb cholinergic projections modulate the generalization of visual aversion possibly via M1 muscarinic acetylcholine receptors (mAChRs) of downstream neurons coreleasing glutamate and acetylcholine. These findings reveal that the MS→MHb cholinergic circuit is a critical node in aversion-generalization formation and extinction and potentially provides insight into the pathogenesis of affective disorders.
Collapse
Affiliation(s)
- Ronghao Mu
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China
| | - Susu Tang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China
| | - Xiaomeng Han
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China
| | - Hao Wang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China
| | - Danhua Yuan
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China
| | - Jiajia Zhao
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China
| | - Yan Long
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China.
| | - Hao Hong
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing 211198, China.
| |
Collapse
|
21
|
Szabo GG, Farrell JS, Dudok B, Hou WH, Ortiz AL, Varga C, Moolchand P, Gulsever CI, Gschwind T, Dimidschstein J, Capogna M, Soltesz I. Ripple-selective GABAergic projection cells in the hippocampus. Neuron 2022; 110:1959-1977.e9. [PMID: 35489331 DOI: 10.1016/j.neuron.2022.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 02/10/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
Ripples are brief high-frequency electrographic events with important roles in episodic memory. However, the in vivo circuit mechanisms coordinating ripple-related activity among local and distant neuronal ensembles are not well understood. Here, we define key characteristics of a long-distance projecting GABAergic cell group in the mouse hippocampus that selectively exhibits high-frequency firing during ripples while staying largely silent during theta-associated states when most other GABAergic cells are active. The high ripple-associated firing commenced before ripple onset and reached its maximum before ripple peak, with the signature theta-OFF, ripple-ON firing pattern being preserved across awake and sleep states. Controlled by septal GABAergic, cholinergic, and CA3 glutamatergic inputs, these ripple-selective cells innervate parvalbumin and cholecystokinin-expressing local interneurons while also targeting a variety of extra-hippocampal regions. These results demonstrate the existence of a hippocampal GABAergic circuit element that is uniquely positioned to coordinate ripple-related neuronal dynamics across neuronal assemblies.
Collapse
Affiliation(s)
- Gergely G Szabo
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
| | - Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Wen-Hsien Hou
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark
| | - Anna L Ortiz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Csaba Varga
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | | | | | - Tilo Gschwind
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| |
Collapse
|
22
|
Xu L, Lin W, Zheng Y, Chen J, Fang Z, Tan N, Hu W, Guo Y, Wang Y, Chen Z. An H2R-dependent medial septum histaminergic circuit mediates feeding behavior. Curr Biol 2022; 32:1937-1948.e5. [PMID: 35338850 DOI: 10.1016/j.cub.2022.03.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/29/2022] [Accepted: 03/02/2022] [Indexed: 11/18/2022]
Abstract
Novel targets for treating feeding-related diseases are of great importance, and histamine has long been considered an anorexigenic agent. However, understanding its functions in feeding in a circuit-specific way is still limited. Here, we report a medial septum (MS)-projecting histaminergic circuit mediating feeding behavior. This MS-projecting histaminergic circuit is functionally inhibited during food consumption, and bidirectionally modulates feeding behavior via downstream H2, but not H1, receptors on MS glutamatergic neurons. Further, we observed a pathological decrease of histamine 2 receptors (H2Rs) expression in MS glutamatergic neurons in diet-induced obesity (DIO) mice. Genetically, down-regulation of H2Rs expression in MS glutamatergic neurons accelerates body-weight gain. Importantly, chronic activation of H2Rs in MS glutamatergic neurons (with its clinical agonist amthamine) significantly slowed down the body-weight gain in DIO mice, providing a possible clinical utility to treat obesity. Together, our results demonstrate that this MS-projecting histaminergic circuit is critically involved in feeding, and H2Rs in MS glutamatergic neurons is a promising target for treating body-weight problems.
Collapse
Affiliation(s)
- Lingyu Xu
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China
| | - Wenkai Lin
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China
| | - Yanrong Zheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Binwen Road, Hangzhou 310053, China
| | - Jialu Chen
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China
| | - Zhuowen Fang
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China
| | - Na Tan
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China
| | - Weiwei Hu
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China
| | - Yi Guo
- Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road, Hangzhou 310009, Zhejiang, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Binwen Road, Hangzhou 310053, China; Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road, Hangzhou 310009, Zhejiang, China
| | - Zhong Chen
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Yuhangtang Road, Hangzhou 310058, China; Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Binwen Road, Hangzhou 310053, China; Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road, Hangzhou 310009, Zhejiang, China.
| |
Collapse
|
23
|
Nedogreeva OA, Evtushenko NA, Manolova AO, Peregud DI, Yakovlev AA, Lazareva NA, Gulyaeva NV, Stepanichev MY. Oxidative Damage of Proteins Precedes Loss of Cholinergic Phenotype in the Septal Neurons of Olfactory Bulbectomized Mice. Curr Alzheimer Res 2021; 18:1140-1151. [PMID: 34951385 DOI: 10.2174/1567205019666211223094051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/04/2021] [Accepted: 12/02/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The development of cholinergic deficit is considered an early sign of a number of pathological conditions, including Alzheimer's disease. Cholinergic dysfunction underlies cognitive decline associated with both normal aging and Alzheimer's disease. OBJECTIVE Here, we studied a possible mechanism of functional impairment of cholinergic neurons using an olfactory bulbectomy model. METHODS Male mice were subjected to olfactory bulbectomy or sham surgery. Three weeks after that they were trained in Morris water maze and then euthanized one month after surgery. The cholinergic indices as well as the indices of oxidative stress were studied using immunohistochemistry, western blot and ELISA. Gene expression was studied using RT-qPCR. RESULTS The experimental treatment was followed by impaired learning of a standard spatial task in a water maze. This was associated with a decrease in the number of cells containing choline acetyltransferase (ChAT), in relation to total number of neurons in the medial septum and lower ChAT enzymatic activity in the hippocampus. However, the levels of mRNAs of ChAT, vesicular ACh transporter and acetylcholine esterase remained unchanged in bulbectomized mice compared to sham-operated animals. These alterations were preceded by the accumulation of protein-bound carbonyls, indicating oxidative damage of proteins, whereas oxidative damage of nucleic acids was not detected. CONCLUSION We assume that in olfactory bulbectomy model, oxidative damage of proteins may cause cholinergic dysfunction rather than irreversible neuronal damage. These data indicate that cholinergic neurons of the basal forebrain are very sensitive to oxidative stress, which may be responsible for the appearance of early cognitive decline in Alzheimer's disease.
Collapse
Affiliation(s)
- O A Nedogreeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - N A Evtushenko
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - A O Manolova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - D I Peregud
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - A A Yakovlev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - N A Lazareva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - N V Gulyaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| | - M Y Stepanichev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Russian Federation
| |
Collapse
|
24
|
Pimpinella D, Mastrorilli V, Giorgi C, Coemans S, Lecca S, Lalive AL, Ostermann H, Fuchs EC, Monyer H, Mele A, Cherubini E, Griguoli M. Septal cholinergic input to CA2 hippocampal region controls social novelty discrimination via nicotinic receptor-mediated disinhibition. eLife 2021; 10:65580. [PMID: 34696824 PMCID: PMC8547952 DOI: 10.7554/elife.65580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 09/30/2021] [Indexed: 12/03/2022] Open
Abstract
Acetylcholine (ACh), released in the hippocampus from fibers originating in the medial septum/diagonal band of Broca (MSDB) complex, is crucial for learning and memory. The CA2 region of the hippocampus has received increasing attention in the context of social memory. However, the contribution of ACh to this process remains unclear. Here, we show that in mice, ACh controls social memory. Specifically, MSDB cholinergic neurons inhibition impairs social novelty discrimination, meaning the propensity of a mouse to interact with a novel rather than a familiar conspecific. This effect is mimicked by a selective antagonist of nicotinic AChRs delivered in CA2. Ex vivo recordings from hippocampal slices provide insight into the underlying mechanism, as activation of nAChRs by nicotine increases the excitatory drive to CA2 principal cells via disinhibition. In line with this observation, optogenetic activation of cholinergic neurons in MSDB increases the firing of CA2 principal cells in vivo. These results point to nAChRs as essential players in social novelty discrimination by controlling inhibition in the CA2 region.
Collapse
Affiliation(s)
- Domenico Pimpinella
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
| | - Valentina Mastrorilli
- Department of Biology and Biotechnology 'C. Darwin', Center for Research in Neurobiology 'D. Bovet', Sapienza University of Rome, Rome, Italy
| | - Corinna Giorgi
- 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), Roma, Italy
| | - Silke Coemans
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
| | - Salvatore Lecca
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Arnaud L Lalive
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Hannah Ostermann
- Department of Clinical Neurobiology of the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Elke C Fuchs
- Department of Clinical Neurobiology of the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology of the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andrea Mele
- Department of Biology and Biotechnology 'C. Darwin', Center for Research in Neurobiology 'D. Bovet', Sapienza University of Rome, Rome, Italy
| | - Enrico Cherubini
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
| | - Marilena Griguoli
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy.,Institute of Neuroscience of the National Research Council (IN-CNR), Pisa, Italy
| |
Collapse
|
25
|
Takeuchi Y, Harangozó M, Pedraza L, Földi T, Kozák G, Li Q, Berényi A. Closed-loop stimulation of the medial septum terminates epileptic seizures. Brain 2021; 144:885-908. [PMID: 33501929 DOI: 10.1093/brain/awaa450] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/29/2020] [Accepted: 10/12/2020] [Indexed: 12/14/2022] Open
Abstract
Temporal lobe epilepsy with distributed hippocampal seizure foci is often intractable and its secondary generalization might lead to sudden death. Early termination through spatially extensive hippocampal intervention is not feasible directly, because of the large size and irregular shape of the hippocampus. In contrast, the medial septum is a promising target to govern hippocampal oscillations through its divergent connections to both hippocampi. Combining this 'proxy intervention' concept and precisely timed stimulation, we report here that closed-loop medial septum electrical stimulation can quickly terminate intrahippocampal seizures and suppress secondary generalization in a rat kindling model. Precise stimulus timing governed by internal seizure rhythms was essential. Cell type-specific stimulation revealed that the precisely timed activation of medial septum GABAergic neurons underlaid the effects. Our concept of time-targeted proxy stimulation for intervening pathological oscillations can be extrapolated to other neurological and psychiatric disorders, and has potential for clinical translation.
Collapse
Affiliation(s)
- Yuichi Takeuchi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary.,Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.,Neurocybernetics Excellence Center, University of Szeged, Szeged 6720, Hungary
| | - Márk Harangozó
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary
| | - Lizeth Pedraza
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged 6720, Hungary
| | - Tamás Földi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged 6720, Hungary
| | - Gábor Kozák
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary
| | - Qun Li
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged 6720, Hungary
| | - Antal Berényi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged 6720, Hungary.,Neurocybernetics Excellence Center, University of Szeged, Szeged 6720, Hungary.,HCEMM-USZ Magnetotherapeutics Research Group, University of Szeged, Szeged 6720, Hungary.,Neuroscience Institute, New York University, New York, NY 10016, USA
| |
Collapse
|
26
|
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: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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.
Collapse
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
| |
Collapse
|
27
|
Ibrahim KM, Ariffin MZ, Khanna S. Modulation of Septo-Hippocampal Neural Responses in Anesthetized and Behaving Rats by Septal AMPA Receptor Mechanisms. Front Neural Circuits 2021; 15:663633. [PMID: 34177470 PMCID: PMC8220821 DOI: 10.3389/fncir.2021.663633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/06/2021] [Indexed: 01/14/2023] Open
Abstract
This study explored the effects of septal glutamatergic transmission on septal-hippocampal theta activity via intraseptal microinjection of antagonist at AMPA receptors (AMPAR). The current results showed that microinjection of AMPAR antagonist, NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione, 20 μg/μl, 0.5 μl), evoked a decrease in the frequency of theta activity evoked by various means in anesthetized and behaving rat. Theta wave activity was induced on: (a) intraseptal microinjection of carbachol, an agonist at cholinergic receptors, (b) reticular stimulation, (c) exploration in novel open field (OF), and (d) hind paw (HP) injection of the algogen, formalin. The effect on frequency in the formalin test was observed in an early period on injection of formalin, which was novel to the animal, but not in the later more sustained phase of the formalin test. The effect of NBQX, being seen in both anesthetized and behaving animals, suggests that the modulation of theta wave frequency, including in novelty, is a function of AMPAR in MS. The effect of the antagonist on theta power was less apparent, being observed only in anesthetized animals. In addition to theta power and frequency, intraseptal NBQX also attenuated suppression of CA1 population spike (PS) induced by intraseptal carbachol, thus suggesting that septal glutamate neurotransmission is involved in the spectrum of MS-mediated network responses. Indeed, in the context of behavior, formalin injection induced an increase in the level of septal glutamate, while NBQX attenuated nociceptive behaviors. Notably, MS is involved in the modulation of formalin nociception. These findings suggest that AMPA receptors are a key modulator of septal physiological function.
Collapse
Affiliation(s)
- Khairunisa Mohamad Ibrahim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Mohammed Zacky Ariffin
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Sanjay Khanna
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| |
Collapse
|
28
|
Wu D, Gao D, Yu H, Pi G, Xiong R, Lei H, Wang X, Liu E, Ye J, Yu H, Gao Y, He T, Jiang T, Sun F, Su J, Song G, Peng W, Yang Y, Wang JZ. Medial septum tau accumulation induces spatial memory deficit via disrupting medial septum-hippocampus cholinergic pathway. Clin Transl Med 2021; 11:e428. [PMID: 34185417 PMCID: PMC8161512 DOI: 10.1002/ctm2.428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/27/2021] [Accepted: 05/04/2021] [Indexed: 01/02/2023] Open
Abstract
Tau accumulation and cholinergic impairment are characteristic pathologies in Alzheimer's disease (AD). However, the causal role of tau accumulation in cholinergic lesion is elusive. Here, we observed an aberrant tau accumulation in the medial septum (MS) of 3xTg and 5xFAD mice, especially in their cholinergic neurons. Overexpressing hTau in mouse MS (MShTau) for 6 months but not 3 months induced spatial memory impairment without changing object recognition and anxiety‐like behavior, indicating a specific and time‐dependent effect of MS‐hTau accumulation on spatial cognitive functions. With increasing hTau accumulation, the MShTau mice showed a time‐dependent cholinergic neuron loss with reduced cholinergic projections to the hippocampus. Intraperitoneal administration of donepezil, a cholinesterase inhibitor, for 1 month ameliorated the MS‐hTau‐induced spatial memory deficits with preservation of MS–hippocampal cholinergic pathway and removal of tau load; and the beneficial effects of donepezil was more prominent at low dose. Proteomics revealed that MS‐hTau accumulation deregulated multiple signaling pathways with numerous differentially expressed proteins (DEPs). Among them, the vacuolar protein sorting‐associated protein 37D (VP37D), an autophagy‐related protein, was significantly reduced in MShTau mice; the reduction of VP37D was restored by donepezil, and the effect was more significant at low dose than high dose. These novel evidences reveal a causal role of tau accumulation in linking MS cholinergic lesion to hippocampus‐dependent spatial cognitive damages as seen in the AD patients, and the new tau‐removal and autophagy‐promoting effects of donepezil may extend its application beyond simple symptom amelioration to potential disease modification.
Collapse
Affiliation(s)
- Dongqin Wu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Di Gao
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haitao Yu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guilin Pi
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Xiong
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiyang Lei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Enjie Liu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinwang Ye
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huilin Yu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Gao
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ting He
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tao Jiang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Sun
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jingfen Su
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guoda Song
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenju Peng
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Yang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| |
Collapse
|
29
|
Abstract
Acetylcholine in the brain promotes arousal and facilitates cognitive functions. Cholinergic neurons in the mesopontine brainstem and basal forebrain are important for activation of the cerebral cortex, which is characterized by the suppression of irregular slow waves, an increase in gamma (30-100 Hz) activity in the electroencephalogram, and the appearance of a hippocampal theta rhythm. During general anesthesia, a decrease in acetylcholine release and cholinergic functions contribute to the desired outcomes of general anesthesia, such as amnesia, loss of awareness and consciousness, and immobility. Animal experiments indicate that inactivation, lesion, or genetic ablation of cholinergic neurons in the basal forebrain potentiated the effects of inhalational and injectable anesthetics, including isoflurane, halothane, propofol, pentobarbital, and in some cases, ketamine. Increased behavioral sensitivity to general anesthesia, faster induction time, and delayed recovery of a loss of righting reflex have been observed in rodents with basal forebrain cholinergic deficits. Cholinergic stimulation in the prefrontal cortex, thalamus, and basal forebrain hastens recovery from general anesthesia. Anticholinesterase accelerates emergence from general anesthesia, but with mixed success, in part depending on the anesthetic used. Cholinergic deficits may contribute to cognitive impairments after anesthesia and operations, which are severe in aged subjects. We propose a cholinergic hypothesis for postoperative cognitive disorder, in line with the cholinergic deficits and cognitive decline in aging and Alzheimer’s disease. The current animal literature suggests that brain cholinergic neurons can regulate the immune and inflammatory response after surgical operation and anesthetic exposure, and anticholinesterase and α7-nicotinic cholinergic agonists can alleviate postoperative inflammatory response and cognitive deficits.
Collapse
Affiliation(s)
- L Stan Leung
- Department of Physiology and Pharmacology, the University of Western Ontario, London, Ontario. Canada
| | - Tao Luo
- Department of Anesthesia, Peking University, Shenzhen, China
| |
Collapse
|
30
|
Nuñez A, Buño W. The Theta Rhythm of the Hippocampus: From Neuronal and Circuit Mechanisms to Behavior. Front Cell Neurosci 2021; 15:649262. [PMID: 33746716 PMCID: PMC7970048 DOI: 10.3389/fncel.2021.649262] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/28/2021] [Indexed: 11/17/2022] Open
Abstract
This review focuses on the neuronal and circuit mechanisms involved in the generation of the theta (θ) rhythm and of its participation in behavior. Data have accumulated indicating that θ arises from interactions between medial septum-diagonal band of Broca (MS-DbB) and intra-hippocampal circuits. The intrinsic properties of MS-DbB and hippocampal neurons have also been shown to play a key role in θ generation. A growing number of studies suggest that θ may represent a timing mechanism to temporally organize movement sequences, memory encoding, or planned trajectories for spatial navigation. To accomplish those functions, θ and gamma (γ) oscillations interact during the awake state and REM sleep, which are considered to be critical for learning and memory processes. Further, we discuss that the loss of this interaction is at the base of various neurophatological conditions.
Collapse
Affiliation(s)
- Angel Nuñez
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autonoma de Madrid, Madrid, Spain
| | - Washington Buño
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas, Madrid, Spain
| |
Collapse
|
31
|
Wang Y, Shen Y, Cai X, Yu J, Chen C, Tan B, Tan N, Cheng H, Fan X, Wu X, Liu J, Wang S, Wang Y, Chen Z. Deep brain stimulation in the medial septum attenuates temporal lobe epilepsy via entrainment of hippocampal theta rhythm. CNS Neurosci Ther 2021; 27:577-586. [PMID: 33502829 PMCID: PMC8025637 DOI: 10.1111/cns.13617] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
Aims Temporal lobe epilepsy (TLE), often associated with cognitive impairment, is one of the most common types of medically refractory epilepsy. Deep brain stimulation (DBS) shows considerable promise for the treatment of TLE. However, the optimal stimulation targets and parameters of DBS to control seizures and related cognitive impairment are still not fully illustrated. Methods In the present study, we evaluated the therapeutic potential of DBS in the medial septum (MS) on seizures and cognitive function in mouse acute and chronic epilepsy models. Results We found that DBS in the MS alleviated the severity of seizure activities in both kainic acid‐induced acute seizure model and hippocampal‐kindled epilepsy model. DBS showed antiseizure effects with a wide window of effective stimulation frequencies. The antiseizure effects of DBS were mediated by the hippocampal theta rhythm, as atropine, which reversed the DBS‐induced augmentation of the hippocampal theta oscillation, abolished the antiseizure effects of DBS. Further, in the kainic acid‐induced chronic TLE model, DBS in the MS not only reduced spontaneous seizures, but also improved behavioral performance in novel object recognition. Conclusion DBS in the MS is a promising approach to attenuate TLE probably through entrainment of the hippocampal theta rhythm, which may be therapeutically significant for refractory TLE treatment.
Collapse
Affiliation(s)
- Ying Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Yating Shen
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xianhui Cai
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Jie Yu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Cong Chen
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Bei Tan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Na Tan
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Heming Cheng
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xiang Fan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaohua Wu
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Jinggen Liu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shuang Wang
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| |
Collapse
|
32
|
Matsuo K, Yabuki Y, Melki R, Bousset L, Owada Y, Fukunaga K. Crucial Role of FABP3 in αSyn-Induced Reduction of Septal GABAergic Neurons and Cognitive Decline in Mice. Int J Mol Sci 2021; 22:E400. [PMID: 33401521 DOI: 10.3390/ijms22010400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 12/27/2020] [Accepted: 12/29/2020] [Indexed: 12/13/2022] Open
Abstract
In synucleinopathies, while motor symptoms are thought to be attributed to the accumulation of misfolded α-synuclein (αSyn) in nigral dopaminergic neurons, it remains to be elucidated how cognitive decline arises. Here, we investigated the effects of distinct αSyn strains on cognition and the related neuropathology in the medial septum/diagonal band (MS/DB), a key region for cognitive processing. Bilateral injection of αSyn fibrils into the dorsal striatum potently impaired cognition in mice. The cognitive decline was accompanied by accumulation of phosphorylated αSyn at Ser129 and reduction of gamma-aminobutyric acid (GABA)-ergic but not cholinergic neurons in the MS/DB. Since we have demonstrated that fatty acid-binding protein 3 (FABP3) is critical for αSyn neurotoxicity in nigral dopaminergic neurons, we investigated whether FABP3 also participates in αSyn pathology in the MS/DB and cognitive decline. FABP3 was highly expressed in GABAergic but rarely in cholinergic neurons in the MS/DB. Notably, Fabp3 deletion antagonized the accumulation of phosphorylated αSyn, decrease in GABAergic neurons, and cognitive impairment caused by αSyn fibrils. Overall, the present study indicates that FABP3 mediates αSyn neurotoxicity in septal GABAergic neurons and the resultant cognitive impairment, and that FABP3 in this subpopulation could be a therapeutic target for dementia in synucleinopathies.
Collapse
|
33
|
Alexander AS, Robinson JC, Dannenberg H, Kinsky NR, Levy SJ, Mau W, Chapman GW, Sullivan DW, Hasselmo ME. Neurophysiological coding of space and time in the hippocampus, entorhinal cortex, and retrosplenial cortex. Brain Neurosci Adv 2020; 4:2398212820972871. [PMID: 33294626 PMCID: PMC7708714 DOI: 10.1177/2398212820972871] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/21/2020] [Indexed: 11/18/2022] Open
Abstract
Neurophysiological recordings in behaving rodents demonstrate neuronal response properties that may code space and time for episodic memory and goal-directed behaviour. Here, we review recordings from hippocampus, entorhinal cortex, and retrosplenial cortex to address the problem of how neurons encode multiple overlapping spatiotemporal trajectories and disambiguate these for accurate memory-guided behaviour. The solution could involve neurons in the entorhinal cortex and hippocampus that show mixed selectivity, coding both time and location. Some grid cells and place cells that code space also respond selectively as time cells, allowing differentiation of time intervals when a rat runs in the same location during a delay period. Cells in these regions also develop new representations that differentially code the context of prior or future behaviour allowing disambiguation of overlapping trajectories. Spiking activity is also modulated by running speed and head direction, supporting the coding of episodic memory not as a series of snapshots but as a trajectory that can also be distinguished on the basis of speed and direction. Recent data also address the mechanisms by which sensory input could distinguish different spatial locations. Changes in firing rate reflect running speed on long but not short time intervals, and few cells code movement direction, arguing against path integration for coding location. Instead, new evidence for neural coding of environmental boundaries in egocentric coordinates fits with a modelling framework in which egocentric coding of barriers combined with head direction generates distinct allocentric coding of location. The egocentric input can be used both for coding the location of spatiotemporal trajectories and for retrieving specific viewpoints of the environment. Overall, these different patterns of neural activity can be used for encoding and disambiguation of prior episodic spatiotemporal trajectories or for planning of future goal-directed spatiotemporal trajectories.
Collapse
Affiliation(s)
| | | | | | | | - Samuel J Levy
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | - William Mau
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | | | - David W Sullivan
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | | |
Collapse
|
34
|
Xu Y, Zhang S, Sun Q, Wang XQ, Chai YN, Mishra C, Chandra SR, Ai J. Cholinergic Dysfunction Involvement in Chronic Cerebral Hypoperfusion-Induced Impairment of Medial Septum-dCA1 Neurocircuit in Rats. Front Cell Neurosci 2020; 14:586591. [PMID: 33132852 PMCID: PMC7550820 DOI: 10.3389/fncel.2020.586591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/31/2020] [Indexed: 11/13/2022] Open
Abstract
Chronic cerebral hypoperfusion (CCH) is considered a preclinical condition of mild cognitive impairment and thought to precede dementia. However, as the principal cholinergic source of hippocampus, whether the septo-hippocampal neurocircuit was impaired after CCH is still unknown. In this study, we established the CCH rat model by bilateral common carotid artery occlusion (2VO). Under anesthesia, the medial septum (MS) of rats was stimulated to evoke the field excitatory post-synaptic potential (fEPSP) in the pyramidal cell layer of dCA1. Consequently, we observed decreased amplitude of fEPSP and increased paired-pulse ratio (PPR) after 8-week CCH. After tail pinch, we also found decreased peak frequency and shortened duration of hippocampal theta rhythm in 2VO rats, indicating the dysfunction of septo-hippocampal neurocircuit. Besides, by intracerebroventricularly injecting GABAergic inhibitor (bicuculline) and cholinergic inhibitors (scopolamine and mecamylamine), we found that CCH impaired both the pre-synaptic cholinergic release and the post-synaptic nAChR function in MS-dCA1 circuits. These results gave an insight into the role of CCH in the impairment of cholinergic MS-dCA1 neurocircuits. These findings may provide a new idea about the CCH-induced neurodegenerative changes.
Collapse
Affiliation(s)
- Yi Xu
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Shuai Zhang
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Qiang Sun
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Xu-Qiao Wang
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Ya-Ni Chai
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Chandan Mishra
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Shah Ram Chandra
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| | - Jing Ai
- Department of Pharmacology, The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy of Harbin Medical University, Harbin, China
| |
Collapse
|
35
|
Koch PF, Cottone C, Adam CD, Ulyanova AV, Russo RJ, Weber MT, Arena JD, Johnson VE, Wolf JA. Traumatic Brain Injury Preserves Firing Rates But Disrupts Laminar Oscillatory Coupling and Neuronal Entrainment in Hippocampal CA1. eNeuro 2020; 7:ENEURO. [PMID: 32737188 DOI: 10.1523/ENEURO.0495-19.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 07/15/2020] [Accepted: 07/19/2020] [Indexed: 11/21/2022] Open
Abstract
While hippocampal-dependent learning and memory are particularly vulnerable to traumatic brain injury (TBI), the functional status of individual hippocampal neurons and their interactions with oscillations are unknown following injury. Using the most common rodent TBI model and laminar recordings in CA1, we found a significant reduction in oscillatory input into the radiatum layer of CA1 after TBI. Surprisingly, CA1 neurons maintained normal firing rates despite attenuated input, but did not maintain appropriate synchronization with this oscillatory input or with local high-frequency oscillations. Normal synchronization between these coordinating oscillations was also impaired. Simultaneous recordings of medial septal neurons known to participate in theta oscillations revealed increased GABAergic/glutamatergic firing rates postinjury under anesthesia, potentially because of a loss of modulating feedback from the hippocampus. These results suggest that TBI leads to a profound disruption of connectivity and oscillatory interactions, potentially disrupting the timing of CA1 neuronal ensembles that underlie aspects of learning and memory.
Collapse
|
36
|
Jin T, Chen R, Shao M, Yang X, Ma L, Wang F. Dorsal hippocampus- and ACC-projecting medial septum neurons differentially contribute to the recollection of episodic-like memory. FASEB J 2020; 34:11741-11753. [PMID: 32652689 DOI: 10.1096/fj.202000398r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/03/2020] [Accepted: 06/19/2020] [Indexed: 11/11/2022]
Abstract
Episodic memory refers to the recollection of previous experiences containing specific temporal, spatial, and emotional information. The ability to recollect episodic memory requires coordination of multiple brain regions, including the hippocampus (HPC) and the cingulate cortex. While the afferents into HPC and cingulate cortex that orchestrate the episodic memory remain unclear. The medial septum (MS), one of the anatomical location of cholinergic centers, innervates not only the dorsal HPC (dHPC), but also the cingulate and entorhinal cortices. By using "What-Where-When" episodic-like memory (ELM) behavioral model and viral tracing, we found that MS neurons projected to dHPC and anterior cingulate cortex (ACC), which exerted distinct impacts on ELM recollection. Chemogenetic inhibition of the dHPC-projecting MS neurons disrupted "What-Where-When" ELM recollection as well as object location, object-in-place, and recency recognition memories recollection, while chemogenetic inhibition of the ACC-projecting MS neurons only disrupted "What-Where-When" ELM recollection. Moreover, neither dHPC- nor ACC-projecting MS neurons were involved in novel object recognition memory recollection or locomotor activity. Immunostaining showed that ACC- and dHPC-projecting MS neurons are partially overlapped populations. These findings reveal an unsuspected division of ELM processing and provide the potential mechanism that the recollection of episodic memory need the coordination of MS neurons projecting to dHPC and ACC.
Collapse
Affiliation(s)
- Tao Jin
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Ruyan Chen
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Mingshuo Shao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xiao Yang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Lan Ma
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Feifei Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| |
Collapse
|
37
|
Petersen PC, Buzsáki G. Cooling of Medial Septum Reveals Theta Phase Lag Coordination of Hippocampal Cell Assemblies. Neuron 2020; 107:731-744.e3. [PMID: 32526196 DOI: 10.1016/j.neuron.2020.05.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/26/2020] [Accepted: 05/16/2020] [Indexed: 12/31/2022]
Abstract
Hippocampal theta oscillations coordinate neuronal firing to support memory and spatial navigation. The medial septum (MS) is critical in theta generation by two possible mechanisms: either a unitary "pacemaker" timing signal is imposed on the hippocampal system, or it may assist in organizing target subcircuits within the phase space of theta oscillations. We used temperature manipulation of the MS to test these models. Cooling of the MS reduced both theta frequency and power and was associated with an enhanced incidence of errors in a spatial navigation task, but it did not affect spatial correlates of neurons. MS cooling decreased theta frequency oscillations of place cells and reduced distance-time compression but preserved distance-phase compression of place field sequences within the theta cycle. Thus, the septum is critical for sustaining precise theta phase coordination of cell assemblies in the hippocampal system, a mechanism needed for spatial memory.
Collapse
Affiliation(s)
| | - György Buzsáki
- Neuroscience Institute, NYU Langone, New York University, New York, NY 10016, USA; Department of Neurology, NYU Langone, New York University, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA.
| |
Collapse
|
38
|
Ma X, Zhang Y, Wang L, Li N, Barkai E, Zhang X, Lin L, Xu J. The Firing of Theta State-Related Septal Cholinergic Neurons Disrupt Hippocampal Ripple Oscillations via Muscarinic Receptors. J Neurosci 2020; 40:3591-603. [PMID: 32265261 DOI: 10.1523/JNEUROSCI.1568-19.2020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [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.
Collapse
|
39
|
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.
Collapse
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
| |
Collapse
|
40
|
Kim S, Nam Y, Jeong YO, Park HH, Lee SK, Shin SJ, Jung H, Kim BH, Hong SB, Park YH, Kim J, Yu J, Yoo DH, Park SH, Jeon SG, Moon M. Topographical Visualization of the Reciprocal Projection between the Medial Septum and the Hippocampus in the 5XFAD Mouse Model of Alzheimer's Disease. Int J Mol Sci 2019; 20:E3992. [PMID: 31426329 DOI: 10.3390/ijms20163992] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 12/13/2022] Open
Abstract
It is widely known that the degeneration of neural circuits is prominent in the brains of Alzheimer’s disease (AD) patients. The reciprocal connectivity of the medial septum (MS) and hippocampus, which constitutes the septo-hippocampo-septal (SHS) loop, is known to be associated with learning and memory. Despite the importance of the reciprocal projections between the MS and hippocampus in AD, the alteration of bidirectional connectivity between two structures has not yet been investigated at the mesoscale level. In this study, we adopted AD animal model, five familial AD mutations (5XFAD) mice, and anterograde and retrograde tracers, BDA and DiI, respectively, to visualize the pathology-related changes in topographical connectivity of the SHS loop in the 5XFAD brain. By comparing 4.5-month-old and 14-month-old 5XFAD mice, we successfully identified key circuit components of the SHS loop altered in 5XFAD brains. Remarkably, the SHS loop began to degenerate in 4.5-month-old 5XFAD mice before the onset of neuronal loss. The impairment of connectivity between the MS and hippocampus was accelerated in 14-month-old 5XFAD mice. These results demonstrate, for the first time, topographical evidence for the degradation of the interconnection between the MS and hippocampus at the mesoscale level in a mouse model of AD. Our results provide structural and functional insights into the interconnectivity of the MS and hippocampus, which will inform the use and development of various therapeutic approaches that target neural circuits for the treatment of AD.
Collapse
|
41
|
Bolding KA, Ferbinteanu J, Fox SE, Muller RU. Place cell firing cannot support navigation without intact septal circuits. Hippocampus 2019; 30:175-191. [PMID: 31301167 DOI: 10.1002/hipo.23136] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 06/12/2019] [Accepted: 06/15/2019] [Indexed: 12/27/2022]
Abstract
Though it has been known for over half a century that interference with the normal activity of septohippocampal neurons can abolish hippocampal theta rhythmicity, a definitive answer to the question of its function has remained elusive. To clarify the role of septal circuits and theta in location-specific activity of place cells and spatial behavior, three drugs were delivered to the medial septum of rats: Tetracaine, a local anesthetic; muscimol, a GABA-A agonist; and gabazine, a GABA-A antagonist. All three drugs disrupted normal oscillatory activity in the hippocampus. However, tetracaine and muscimol both reduced spatial firing and interfered with the rat's ability to navigate to a hidden goal. After gabazine, location-specific firing was preserved in the absence of theta, but rats were unable to accurately locate the hidden goal. These results indicate that theta is unnecessary for location-specific firing of hippocampal cells, and that place cell activity cannot support accurate navigation when septal circuits are disrupted.
Collapse
Affiliation(s)
- Kevin A Bolding
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York.,Department of Neurobiology, Duke University Medical School, Durham, North Carolina
| | - Janina Ferbinteanu
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York.,Department of Neurology, State University of New York, Downstate Medical Center, Brooklyn, New York
| | - Steven E Fox
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York
| | - Robert U Muller
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York
| |
Collapse
|
42
|
Salib M, Joshi A, Katona L, Howarth M, Micklem BR, Somogyi P, Viney TJ. GABAergic Medial Septal Neurons with Low-Rhythmic Firing Innervating the Dentate Gyrus and Hippocampal Area CA3. J Neurosci 2019; 39:4527-49. [PMID: 30926750 DOI: 10.1523/JNEUROSCI.3024-18.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/08/2019] [Accepted: 03/15/2019] [Indexed: 02/06/2023] Open
Abstract
The medial septum implements cortical theta oscillations, a 5–12 Hz rhythm associated with locomotion and paradoxical sleep reflecting synchronization of neuronal assemblies such as place cell sequence coding. Highly rhythmic burst-firing parvalbumin-positive GABAergic medial septal neurons are strongly coupled to theta oscillations and target cortical GABAergic interneurons, contributing to coordination within one or several cortical regions. However, a large population of medial septal neurons of unidentified neurotransmitter phenotype and with unknown axonal target areas fire with a low degree of rhythmicity. We investigated whether low-rhythmic-firing neurons (LRNs) innervated similar or different cortical regions to high-rhythmic-firing neurons (HRNs) and assessed their temporal dynamics in awake male mice. The majority of LRNs were GABAergic and parvalbumin-immunonegative, some expressing calbindin; they innervated interneurons mostly in the dentate gyrus (DG) and CA3. Individual LRNs showed several distinct firing patterns during immobility and locomotion, forming a parallel inhibitory stream for the modulation of cortical interneurons. Despite their fluctuating firing rates, the preferred firing phase of LRNs during theta oscillations matched the highest firing probability phase of principal cells in the DG and CA3. In addition, as a population, LRNs were markedly suppressed during hippocampal sharp-wave ripples, had a low burst incidence, and several of them did not fire on all theta cycles. Therefore, CA3 receives GABAergic input from both HRNs and LRNs, but the DG receives mainly LRN input. We propose that distinct GABAergic LRNs contribute to changing the excitability of the DG and CA3 during memory discrimination via transient disinhibition of principal cells. SIGNIFICANCE STATEMENT For the encoding and recall of episodic memories, nerve cells in the cerebral cortex are activated in precisely timed sequences. Rhythmicity facilitates the coordination of neuronal activity and these rhythms are detected as oscillations of different frequencies such as 5–12 Hz theta oscillations. Degradation of these rhythms, such as through neurodegeneration, causes memory deficits. The medial septum, a part of the basal forebrain that innervates the hippocampal formation, contains high- and low-rhythmic-firing neurons (HRNs and LRNs, respectively), which may contribute differentially to cortical neuronal coordination. We discovered that GABAergic LRNs preferentially innervate the dentate gyrus and the CA3 area of the hippocampus, regions important for episodic memory. These neurons act in parallel with the HRNs mostly via transient inhibition of inhibitory neurons.
Collapse
|
43
|
Dannenberg H, Kelley C, Hoyland A, Monaghan CK, Hasselmo ME. The Firing Rate Speed Code of Entorhinal Speed Cells Differs across Behaviorally Relevant Time Scales and Does Not Depend on Medial Septum Inputs. J Neurosci 2019; 39:3434-53. [PMID: 30804092 DOI: 10.1523/JNEUROSCI.1450-18.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 02/06/2019] [Accepted: 02/10/2019] [Indexed: 12/13/2022] Open
Abstract
The firing rate of speed cells, a dedicated subpopulation of neurons in the medial entorhinal cortex (MEC), is correlated with running speed. This correlation has been interpreted as a speed code used in various computational models for path integration. These models consider firing rate to be linearly tuned by running speed in real-time. However, estimation of firing rates requires integration of spiking events over time, setting constraints on the temporal accuracy of the proposed speed code. We therefore tested whether the proposed speed code by firing rate is accurate at short time scales using data obtained from open-field recordings in male rats and mice. We applied a novel filtering approach differentiating between speed codes at multiple time scales ranging from deciseconds to minutes. In addition, we determined the optimal integration time window for firing-rate estimation using a general likelihood framework and calculated the integration time window that maximizes the correlation between firing rate and running speed. Data show that these time windows are on the order of seconds, setting constraints on real-time speed coding by firing rate. We further show that optogenetic inhibition of either cholinergic, GABAergic, or glutamatergic neurons in the medial septum/diagonal band of Broca does not affect modulation of firing rates by running speed at each time scale tested. These results are relevant for models of path integration and for our understanding of how behavioral activity states may modulate firing rates and likely information processing in the MEC.SIGNIFICANCE STATEMENT Path integration is the most basic form of navigation relying on self-motion cues. Models of path integration use medial septum/diagonal band of Broca (MSDB)-dependent MEC grid-cell firing patterns as the neurophysiological substrate of path integration. These models use a linear speed code by firing rate, but do not consider temporal constraints of integration over time for firing-rate estimation. We show that firing-rate estimation for speed cells requires integration over seconds. Using optogenetics, we show that modulation of firing rates by running speed is independent of MSDB inputs. These results enhance our understanding of path integration mechanisms and the role of the MSDB for information processing in the MEC.
Collapse
|
44
|
Zhang GW, Shen L, Zhong W, Xiong Y, Zhang LI, Tao HW. Transforming Sensory Cues into Aversive Emotion via Septal-Habenular Pathway. Neuron 2018; 99:1016-1028.e5. [PMID: 30122379 DOI: 10.1016/j.neuron.2018.07.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/02/2018] [Accepted: 07/17/2018] [Indexed: 11/23/2022]
Abstract
Emotions evoked by environmental cues are important for animal survival and life quality. However, neural circuits responsible for transforming sensory signals to aversive emotion and behavioral avoidance remain unclear. Here, we found that medial septum (MS) mediates aversion induced by both auditory and somatosensory stimuli. Ablation of glutamatergic or GABAergic MS neurons results in impaired or strengthened aversion, respectively. Optogenetic activation of the two cell types results in place avoidance and preference, respectively. Cell-type-specific screening reveals that glutamatergic MS projections to the lateral habenula (LHb) are responsible for the induction of aversion, which can be antagonized by GABAergic MS projections to LHb. Additionally, the sensory-induced place avoidance is facilitated by enhanced locomotion mediated by glutamatergic MS projections to the preoptic area. Thus, MS can transmit innately aversive signals via a bottom-up multimodal sensory pathway and produce concurrent emotional and motional effects, allowing animals to efficiently avoid unfavorable environments.
Collapse
|
45
|
Chen BH, Park JH, Kim DW, Park J, Choi SY, Kim IH, Cho JH, Lee TK, Lee JC, Lee CH, Hwang IK, Kim YM, Yan BC, Kang IJ, Shin BN, Lee YL, Shin MC, Cho JH, Lee YJ, Jeon YH, Won MH, Ahn JH. Melatonin Improves Cognitive Deficits via Restoration of Cholinergic Dysfunction in a Mouse Model of Scopolamine-Induced Amnesia. ACS Chem Neurosci 2018; 9:2016-2024. [PMID: 28901737 DOI: 10.1021/acschemneuro.7b00278] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Melatonin is known to improve cognitive deficits, and its functions have been studied in various disease models, including Alzheimer's disease. In this study, we investigated effects of melatonin on cognition and the cholinergic system of the septum and hippocampus in a mouse model of scopolamine-induced amnesia. Scopolamine (1 mg/kg) and melatonin (10 mg/kg) were administered intraperitoneally to mice for 2 and 4 weeks. The Morris water maze and passive avoidance tests revealed that both treatments of scopolamine significantly impaired spatial learning and memory; however, 2- and 4-week melatonin treatments significantly improved spatial learning and memory. In addition, scopolamine treatments significantly decreased protein levels and immunoreactivities of choline acetyltransferase (ChAT), high-affinity choline transporter (CHT), vesicular acetylcholine transporter (VAChT), and muscarinic acetylcholine receptor M1 (M1R) in the septum and hippocampus. However, the treatments with melatonin resulted in increased ChAT-, CHT-, VAChT-, and M1R-immunoreactivities and their protein levels in the septum and hippocampus. Our results demonstrate that melatonin treatment is effective in improving the cognitive deficits via restoration of the cholinergic system in the septum and hippocampus of a mouse model of scopolamine-induced amnesia.
Collapse
Affiliation(s)
- Bai Hui Chen
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Joon Ha Park
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, South Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, and Research Institute of Oral Sciences, College of Dentistry, Kangnung-Wonju National University, Gangneung 25457, South Korea
| | - Jinseu Park
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, South Korea
| | - Soo Young Choi
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, South Korea
| | - In Hye Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Jeong Hwi Cho
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Tae-Kyeong Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Jae Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Choong-Hyun Lee
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, South Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Young-Myeong Kim
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Bing Chun Yan
- Jiangsu Key Laboratory
of Integrated Traditional Chinese and Western Medicine for Prevention
and Treatment of Senile Diseases, Yangzhou 225001, People’s Republic of China
| | - Il Jun Kang
- Department of Food Science and Nutrition, Hallym University, Chuncheon 24252, South Korea
| | - Bich Na Shin
- Department of Physiology, College of Medicine, and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 24252, South Korea
| | - Yun Lyul Lee
- Department of Physiology, College of Medicine, and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 24252, South Korea
| | - Myoung Cheol Shin
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Young Joo Lee
- Department of Emergency Medicine, Seoul Hospital, College of Medicine, Sooncheonhyang University, Seoul 04401, South Korea
| | - Yong Hwan Jeon
- Department of Radiology, School of Medicine, Kangwon National University, Chuncheon 24289, South Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, South Korea
| | - Ji Hyeon Ahn
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, South Korea
| |
Collapse
|
46
|
Gu Z, Alexander GM, Dudek SM, Yakel JL. Hippocampus and Entorhinal Cortex Recruit Cholinergic and NMDA Receptors Separately to Generate Hippocampal Theta Oscillations. Cell Rep 2018; 21:3585-3595. [PMID: 29262336 DOI: 10.1016/j.celrep.2017.11.080] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/10/2017] [Accepted: 11/21/2017] [Indexed: 11/25/2022] Open
Abstract
Although much progress has been made in understanding type II theta rhythm generation under urethane anesthesia, less is known about the mechanisms underlying type I theta generation during active exploration. To better understand the contributions of cholinergic and NMDA receptor activation to type I theta generation, we recorded hippocampal theta oscillations from freely moving mice with local infusion of cholinergic or NMDA receptor antagonists to either the hippocampus or the entorhinal cortex (EC). We found that cholinergic receptors in the hippocampus, but not the EC, and NMDA receptors in the EC, but not the hippocampus, are critical for open-field theta generation and Y-maze performance. We further found that muscarinic M1 receptors located on pyramidal neurons, but not interneurons, are critical for cholinergic modulation of hippocampal synapses, theta generation, and Y-maze performance. These results suggest that hippocampus and EC neurons recruit cholinergic-dependent and NMDA-receptor-dependent mechanisms, respectively, to generate theta oscillations to support behavioral performance.
Collapse
Affiliation(s)
- Zhenglin Gu
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Georgia M Alexander
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
| |
Collapse
|
47
|
Fattahi M, Sharif F, Geiller T, Royer S. Differential Representation of Landmark and Self-Motion Information along the CA1 Radial Axis: Self-Motion Generated Place Fields Shift toward Landmarks during Septal Inactivation. J Neurosci 2018; 38:6766-78. [PMID: 29954846 DOI: 10.1523/JNEUROSCI.3211-17.2018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/13/2018] [Accepted: 06/19/2018] [Indexed: 11/21/2022] Open
Abstract
Spatial location in the environment can be defined in relation to specific landmarks or in relation to the global context, and is estimated from both the sensing of landmarks and the inner sense of cumulated locomotion referred to as path-integration. The respective contribution of landmark and path-integration to place-cell activity in the hippocampus is still unclear and complicated by the fact that the two mechanisms usually overlap. To bias spatial mechanisms toward landmark or path-integration, we use a treadmill equipped with a long belt on which male mice run sequentially through a zone enriched and a zone impoverished in visual-tactile cues. We show that inactivation of the medial septum (MS), which is known to disrupt the periodic activity of grid cells, impairs mice ability to anticipate the delivery of a reward in the cue-impoverished zone and transiently alter the spatial configuration of place fields in the cue-impoverished zone selectively: following MS inactivation, place fields in the cue-impoverished zone progressively shift backward and stabilize near the cues, resulting in the contraction of the spatial representation around cues; following MS recovery, the initial spatial representation is progressively restored. Furthermore, we found that place fields in the cue-rich and cue-impoverished zones are preferentially generated by cells from the deep and superficial sublayers of CA1, respectively. These findings demonstrate with mechanistic insights the contribution of MS to the spread of spatial representations in cue-impoverished zones, and indicate a segregation of landmark-based and path-integration-assisted spatial mechanisms into deep and superficial CA1, respectively.SIGNIFICANCE STATEMENT Cells encoding a cue-impoverished zone and the vicinity of landmarks responded differentially to septal inactivation and resided in distinct sublayers of CA1. These findings provide new insights on place field mechanisms: septal activity is critical for maintaining the spread of place fields in cue-impoverished areas, but not for the generation of place fields; Following MS inactivation, trial-by-trial network modifications by activity-dependent mechanisms are responsible for the gradual collapse of spatial representations. Furthermore, the findings suggest parallel coding streams for landmark and self-motion information. Superficial CA1 cells are better suited for encoding global position via the assist of path-integration, whereas deep CA1 cells can support spatial memory processes on an object-specific basis.
Collapse
|
48
|
Viney TJ, Salib M, Joshi A, Unal G, Berry N, Somogyi P. Shared rhythmic subcortical GABAergic input to the entorhinal cortex and presubiculum. eLife 2018; 7:e34395. [PMID: 29620525 PMCID: PMC5908441 DOI: 10.7554/elife.34395] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/04/2018] [Indexed: 01/06/2023] Open
Abstract
Rhythmic theta frequency (~5-12 Hz) oscillations coordinate neuronal synchrony and higher frequency oscillations across the cortex. Spatial navigation and context-dependent episodic memories are represented in several interconnected regions including the hippocampal and entorhinal cortices, but the cellular mechanisms for their dynamic coupling remain to be defined. Using monosynaptically-restricted retrograde viral tracing in mice, we identified a subcortical GABAergic input from the medial septum that terminated in the entorhinal cortex, with collaterals innervating the dorsal presubiculum. Extracellularly recording and labeling GABAergic entorhinal-projecting neurons in awake behaving mice show that these subcortical neurons, named orchid cells, fire in long rhythmic bursts during immobility and locomotion. Orchid cells discharge near the peak of hippocampal and entorhinal theta oscillations, couple to entorhinal gamma oscillations, and target subpopulations of extra-hippocampal GABAergic interneurons. Thus, orchid cells are a specialized source of rhythmic subcortical GABAergic modulation of 'upstream' and 'downstream' cortico-cortical circuits involved in mnemonic functions.
Collapse
Affiliation(s)
- Tim James Viney
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Minas Salib
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Abhilasha Joshi
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Gunes Unal
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Naomi Berry
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Peter Somogyi
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| |
Collapse
|
49
|
Desikan S, Koser DE, Neitz A, Monyer H. Target selectivity of septal cholinergic neurons in the medial and lateral entorhinal cortex. Proc Natl Acad Sci U S A 2018; 115:E2644-52. [PMID: 29487212 DOI: 10.1073/pnas.1716531115] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Acetylcholine is a key modulator of hippocampal and entorhinal cortex (EC) function. The majority of cholinergic projections targeting these structures originate in the basal forebrain complex, specifically the medial septum. Many studies focused on the behavioral effects involving these projections, but there still is a paucity regarding their connectivity in the target area. Here we provide this missing link. By combining optogenetics with whole-cell recordings in superficial EC layers, we identified the synaptic target cells of septal cholinergic neurons. This level of analysis is an important step toward a better understanding of the modulatory action of acetylcholine in EC in vivo. The entorhinal cortex (EC) plays a pivotal role in processing and conveying spatial information to the hippocampus. It has long been known that EC neurons are modulated by cholinergic input from the medial septum. However, little is known as to how synaptic release of acetylcholine affects the different cell types in EC. Here we combined optogenetics and patch-clamp recordings to study the effect of cholinergic axon stimulation on distinct neurons in EC. We found dense cholinergic innervations that terminate in layer I and II (LI and LII). Light-activated stimulation of septal cholinergic projections revealed differential responses in excitatory and inhibitory neurons in LI and LII of both medial and lateral EC. We observed depolarizing responses mediated by nicotinic and muscarinic receptors primarily in putative serotonin receptor (p5HT3R)-expressing interneurons. Hyperpolarizing muscarinic receptor-mediated responses were found predominantly in excitatory cells. Additionally, some excitatory as well as a higher fraction of inhibitory neurons received mono- and/or polysynaptic GABAergic inputs, revealing that medial septum cholinergic neurons have the capacity to corelease GABA alongside acetylcholine. Notably, the synaptic effects of acetylcholine were similar in neurons of both medial and lateral EC. Taken together, our findings demonstrate that EC activity may be differentially modulated via the activation or the suppression of distinct subsets of LI and LII neurons by the septal cholinergic system.
Collapse
|
50
|
Abstract
Feeding behavior is controlled by diverse neurons and neural circuits primarily concentrated in the hypothalamus and hindbrain in mammals. In this study, by using chemo/optogenetic techniques along with feeding assays, we investigate how neurons within the medial septal complex (MSc), a brain area implicated in emotion and cognition, contribute to food intake. We find that chemo/optogenetic activation of MSc glutamatergic neurons profoundly reduces food intake during both light and dark periods of the rodent light cycle. Furthermore, we find that selective activation of MSc glutamatergic projections in paraventricular hypothalamus (PVH) reduces food intake, suggesting that MSc glutamatergic neurons suppress feeding by activating downstream neurons in the PVH. Open-field behavioral assays reveal that these neurons do not overtly affect anxiety levels and locomotion. Collectively, our findings demonstrate that septal glutamatergic neurons exert anorexigenic effects by projecting to the PVH without affecting anxiety and physical activities.
Collapse
|