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Robinson JC, Ying J, Hasselmo ME, Brandon MP. Optogenetic silencing of medial septal GABAergic neurons disrupts grid cell spatial and temporal coding in the medial entorhinal cortex. Cell Rep 2024; 43:114590. [PMID: 39163200 DOI: 10.1016/j.celrep.2024.114590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/29/2024] [Accepted: 07/21/2024] [Indexed: 08/22/2024] Open
Abstract
The hippocampus and medial entorhinal cortex (MEC) form a cognitive map that facilitates spatial navigation. As part of this map, MEC grid cells fire in a repeating hexagonal pattern across an environment. This grid pattern relies on inputs from the medial septum (MS). The MS, and specifically GABAergic neurons, are essential for theta rhythm oscillations in the entorhinal-hippocampal network; however, the role of this population in grid cell function is unclear. To investigate this, we use optogenetics to inhibit MS-GABAergic neurons and observe that MS-GABAergic inhibition disrupts grid cell spatial periodicity. Grid cell spatial periodicity is disrupted during both optogenetic inhibition periods and short inter-stimulus intervals. In contrast, longer inter-stimulus intervals allow for the recovery of grid cell spatial firing. In addition, grid cell phase precession is also disrupted. These findings highlight the critical role of MS-GABAergic neurons in maintaining grid cell spatial and temporal coding in the MEC.
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Affiliation(s)
- Jennifer C Robinson
- Center for Systems Neuroscience, Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA.
| | - Johnson Ying
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Michael E Hasselmo
- Center for Systems Neuroscience, Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | - Mark P Brandon
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
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2
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Robinson JC, Ying J, Hasselmo ME, Brandon MP. Optogenetic Silencing of Medial Septal GABAergic Neurons Disrupts Grid Cell Spatial and Temporal Coding in the Medial Entorhinal Cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566228. [PMID: 37986986 PMCID: PMC10659309 DOI: 10.1101/2023.11.08.566228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The hippocampus and medial entorhinal cortex (MEC) form a cognitive map that facilitates spatial navigation. As part of this map, MEC grid cells fire in a repeating hexagonal pattern across an environment. This grid pattern relies on inputs from the medial septum (MS). The MS, and specifically its GABAergic neurons, are essential for theta rhythm oscillations in the entorhinal-hippocampal network, however, it is unknown if this subpopulation is also essential for grid cell function. To investigate this, we used optogenetics to inhibit MS-GABAergic neurons during grid cell recordings. We found that MS-GABAergic inhibition disrupted grid cell spatial periodicity both during optogenetic inhibition and during short 30-second recovery periods. Longer recovery periods of 60 seconds between the optogenetic inhibition periods allowed for the recovery of grid cell spatial firing. Grid cell temporal coding was also disrupted, as observed by a significant attenuation of theta phase precession. Together, these results demonstrate that MS-GABAergic neurons are critical for grid cell spatial and temporal coding in the MEC.
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Broussard JI, Redell JB, Zhao J, West R, Homma R, Dash PK. Optogenetic Stimulation of CA1 Pyramidal Neurons at Theta Enhances Recognition Memory in Brain Injured Animals. J Neurotrauma 2023; 40:2442-2448. [PMID: 37387400 PMCID: PMC10653071 DOI: 10.1089/neu.2023.0078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023] Open
Abstract
Abstract The hippocampus plays a prominent role in learning and memory formation. The functional integrity of this structure is often compromised after traumatic brain injury (TBI), resulting in lasting cognitive dysfunction. The activity of hippocampal neurons, particularly place cells, is coordinated by local theta oscillations. Previous studies aimed at examining hippocampal theta oscillations after experimental TBI have reported disparate findings. Using a diffuse brain injury model, the lateral fluid percussion injury (FPI; 2.0 atm), we report a significant reduction in hippocampal theta power that persists for at least three weeks after injury. We questioned whether the behavioral deficit associated with this reduction of theta power can be overcome by optogenetically stimulating CA1 neurons at theta in brain injured rats. Our results show that memory impairments in brain injured animals could be reversed by optogenetically stimulating CA1 pyramidal neurons expressing channelrhodopsin (ChR2) during learning. In contrast, injured animals receiving a control virus (lacking ChR2) did not benefit from optostimulation. These results suggest that direct stimulation of CA1 pyramidal neurons at theta may be a viable option for enhancing memory after TBI.
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Affiliation(s)
- John I. Broussard
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - John B. Redell
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Jing Zhao
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Rebecca West
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Ryota Homma
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Pramod K. Dash
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
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Király B, Domonkos A, Jelitai M, Lopes-Dos-Santos V, Martínez-Bellver S, Kocsis B, Schlingloff D, Joshi A, Salib M, Fiáth R, Barthó P, Ulbert I, Freund TF, Viney TJ, Dupret D, Varga V, Hangya B. The medial septum controls hippocampal supra-theta oscillations. Nat Commun 2023; 14:6159. [PMID: 37816713 PMCID: PMC10564782 DOI: 10.1038/s41467-023-41746-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/15/2023] [Indexed: 10/12/2023] Open
Abstract
Hippocampal theta oscillations orchestrate faster beta-to-gamma oscillations facilitating the segmentation of neural representations during navigation and episodic memory. Supra-theta rhythms of hippocampal CA1 are coordinated by local interactions as well as inputs from the entorhinal cortex (EC) and CA3 inputs. However, theta-nested gamma-band activity in the medial septum (MS) suggests that the MS may control supra-theta CA1 oscillations. To address this, we performed multi-electrode recordings of MS and CA1 activity in rodents and found that MS neuron firing showed strong phase-coupling to theta-nested supra-theta episodes and predicted changes in CA1 beta-to-gamma oscillations on a cycle-by-cycle basis. Unique coupling patterns of anatomically defined MS cell types suggested that indirect MS-to-CA1 pathways via the EC and CA3 mediate distinct CA1 gamma-band oscillations. Optogenetic activation of MS parvalbumin-expressing neurons elicited theta-nested beta-to-gamma oscillations in CA1. Thus, the MS orchestrates hippocampal network activity at multiple temporal scales to mediate memory encoding and retrieval.
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Affiliation(s)
- Bálint Király
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Department of Biological Physics, Institute of Physics, Eötvös Loránd University, Budapest, Hungary
| | - Andor Domonkos
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Márta Jelitai
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Vítor Lopes-Dos-Santos
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Sergio Martínez-Bellver
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Department of Anatomy and Human Embryology, Faculty of Medicine and Odontology, University of Valencia, Valencia, Spain
| | - Barnabás Kocsis
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Dániel Schlingloff
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Minas Salib
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Richárd Fiáth
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Péter Barthó
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - István Ulbert
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Tamás F Freund
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Tim J Viney
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - David Dupret
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Viktor Varga
- Subcortical Modulation Research Group, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary.
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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] [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.
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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.
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6
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Etter G, Carmichael JE, Williams S. Linking temporal coordination of hippocampal activity to memory function. Front Cell Neurosci 2023; 17:1233849. [PMID: 37720546 PMCID: PMC10501408 DOI: 10.3389/fncel.2023.1233849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/01/2023] [Indexed: 09/19/2023] Open
Abstract
Oscillations in neural activity are widespread throughout the brain and can be observed at the population level through the local field potential. These rhythmic patterns are associated with cycles of excitability and are thought to coordinate networks of neurons, in turn facilitating effective communication both within local circuits and across brain regions. In the hippocampus, theta rhythms (4-12 Hz) could contribute to several key physiological mechanisms including long-range synchrony, plasticity, and at the behavioral scale, support memory encoding and retrieval. While neurons in the hippocampus appear to be temporally coordinated by theta oscillations, they also tend to fire in sequences that are developmentally preconfigured. Although loss of theta rhythmicity impairs memory, these sequences of spatiotemporal representations persist in conditions of altered hippocampal oscillations. The focus of this review is to disentangle the relative contribution of hippocampal oscillations from single-neuron activity in learning and memory. We first review cellular, anatomical, and physiological mechanisms underlying the generation and maintenance of hippocampal rhythms and how they contribute to memory function. We propose candidate hypotheses for how septohippocampal oscillations could support memory function while not contributing directly to hippocampal sequences. In particular, we explore how theta rhythms could coordinate the integration of upstream signals in the hippocampus to form future decisions, the relevance of such integration to downstream regions, as well as setting the stage for behavioral timescale synaptic plasticity. Finally, we leverage stimulation-based treatment in Alzheimer's disease conditions as an opportunity to assess the sufficiency of hippocampal oscillations for memory function.
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Affiliation(s)
| | | | - Sylvain Williams
- Department of Psychiatry, Douglas Mental Health Research Institute, McGill University, Montreal, QC, Canada
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Traub RD, Whittington MA, Cunningham MO. Simulation of oscillatory dynamics induced by an approximation of grid cell output. Rev Neurosci 2023; 34:517-532. [PMID: 36326795 PMCID: PMC10329426 DOI: 10.1515/revneuro-2022-0107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/06/2022] [Indexed: 07/20/2023]
Abstract
Grid cells, in entorhinal cortex (EC) and related structures, signal animal location relative to hexagonal tilings of 2D space. A number of modeling papers have addressed the question of how grid firing behaviors emerge using (for example) ideas borrowed from dynamical systems (attractors) or from coupled oscillator theory. Here we use a different approach: instead of asking how grid behavior emerges, we take as a given the experimentally observed intracellular potentials of superficial medial EC neurons during grid firing. Employing a detailed neural circuit model modified from a lateral EC model, we then ask how the circuit responds when group of medial EC principal neurons exhibit such potentials, simultaneously with a simulated theta frequency input from the septal nuclei. The model predicts the emergence of robust theta-modulated gamma/beta oscillations, suggestive of oscillations observed in an in vitro medial EC experimental model (Cunningham, M.O., Pervouchine, D.D., Racca, C., Kopell, N.J., Davies, C.H., Jones, R.S.G., Traub, R.D., and Whittington, M.A. (2006). Neuronal metabolism governs cortical network response state. Proc. Natl. Acad. Sci. U S A 103: 5597-5601). Such oscillations result because feedback interneurons tightly synchronize with each other - despite the varying phases of the grid cells - and generate a robust inhibition-based rhythm. The lack of spatial specificity of the model interneurons is consistent with the lack of spatial periodicity in parvalbumin interneurons observed by Buetfering, C., Allen, K., and Monyer, H. (2014). Parvalbumin interneurons provide grid cell-driven recurrent inhibition in the medial entorhinal cortex. Nat. Neurosci. 17: 710-718. If in vivo EC gamma rhythms arise during exploration as our model predicts, there could be implications for interpreting disrupted spatial behavior and gamma oscillations in animal models of Alzheimer's disease and schizophrenia. Noting that experimental intracellular grid cell potentials closely resemble cortical Up states and Down states, during which fast oscillations also occur during Up states, we propose that the co-occurrence of slow principal cell depolarizations and fast network oscillations is a general property of the telencephalon, in both waking and sleep states.
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Affiliation(s)
- Roger D. Traub
- AI Foundations, IBM T.J. Watson Research Center, Yorktown Heights, NY10598, USA
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104, USA
| | | | - Mark O. Cunningham
- Discipline of Physiology, School of Medicine, Trinity College Dublin, University of Dublin, 152-160 Pearse St., Dublin 2, Ireland
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8
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Shi Y, Cui H, Li X, Chen L, Zhang C, Zhao X, Li X, Shao Q, Sun Q, Yan K, Wang G. Laminar and dorsoventral organization of layer 1 interneuronal microcircuitry in superficial layers of the medial entorhinal cortex. Cell Rep 2023; 42:112782. [PMID: 37436894 DOI: 10.1016/j.celrep.2023.112782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 04/03/2023] [Accepted: 06/24/2023] [Indexed: 07/14/2023] Open
Abstract
Layer 1 (L1) interneurons (INs) participate in various brain functions by gating information flow in the neocortex, but their role in the medial entorhinal cortex (MEC) is still unknown, largely due to scant knowledge of MEC L1 microcircuitry. Using simultaneous triple-octuple whole-cell recordings and morphological reconstructions, we comprehensively depict L1IN networks in the MEC. We identify three morphologically distinct types of L1INs with characteristic electrophysiological properties. We dissect intra- and inter-laminar cell-type-specific microcircuits of L1INs, showing connectivity patterns different from those in the neocortex. Remarkably, motif analysis reveals transitive and clustered features of L1 networks, as well as over-represented trans-laminar motifs. Finally, we demonstrate the dorsoventral gradient of L1IN microcircuits, with dorsal L1 neurogliaform cells receiving fewer intra-laminar inputs but exerting more inhibition on L2 principal neurons. These results thus present a more comprehensive picture of L1IN microcircuitry, which is indispensable for deciphering the function of L1INs in the MEC.
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Affiliation(s)
- Yuying Shi
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Hui Cui
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Xiaoyue Li
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Ligu Chen
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Chen Zhang
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Xinran Zhao
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Xiaowan Li
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Qiming Shao
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Qiang Sun
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Kaiyue Yan
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Guangfu Wang
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China.
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9
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Osanai H, Nair IR, Kitamura T. Dissecting cell-type-specific pathways in medial entorhinal cortical-hippocampal network for episodic memory. J Neurochem 2023; 166:172-188. [PMID: 37248771 PMCID: PMC10538947 DOI: 10.1111/jnc.15850] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/07/2023] [Accepted: 05/10/2023] [Indexed: 05/31/2023]
Abstract
Episodic memory, which refers to our ability to encode and recall past events, is essential to our daily lives. Previous research has established that both the entorhinal cortex (EC) and hippocampus (HPC) play a crucial role in the formation and retrieval of episodic memories. However, to understand neural circuit mechanisms behind these processes, it has become necessary to monitor and manipulate the neural activity in a cell-type-specific manner with high temporal precision during memory formation, consolidation, and retrieval in the EC-HPC networks. Recent studies using cell-type-specific labeling, monitoring, and manipulation have demonstrated that medial EC (MEC) contains multiple excitatory neurons that have differential molecular markers, physiological properties, and anatomical features. In this review, we will comprehensively examine the complementary roles of superficial layers of neurons (II and III) and the roles of deeper layers (V and VI) in episodic memory formation and recall based on these recent findings.
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Affiliation(s)
- Hisayuki Osanai
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Indrajith R Nair
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Takashi Kitamura
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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10
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Tang Y, Yan Y, Mao J, Ni J, Qing H. The hippocampus associated GABAergic neural network impairment in early-stage of Alzheimer's disease. Ageing Res Rev 2023; 86:101865. [PMID: 36716975 DOI: 10.1016/j.arr.2023.101865] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 01/29/2023]
Abstract
Alzheimer's disease (AD) is the commonest neurodegenerative disease with slow progression. Pieces of evidence suggest that the GABAergic system is impaired in the early stage of AD, leading to hippocampal neuron over-activity and further leading to memory and cognitive impairment in patients with AD. However, the precise impairment mechanism of the GABAergic system on the pathogenesis of AD is still unclear. The impairment of neural networks associated with the GABAergic system is tightly associated with AD. Therefore, we describe the roles played by hippocampus-related GABAergic circuits and their impairments in AD neuropathology. In addition, we give our understand on the process from GABAergic circuit impairment to cognitive and memory impairment, since recent studies on astrocyte in AD plays an important role behind cognition dysfunction caused by GABAergic circuit impairment, which helps better understand the GABAergic system and could open up innovative AD therapy.
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Affiliation(s)
- Yuanhong Tang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yan Yan
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jian Mao
- Zhengzhou Tobacco Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China.
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11
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Salimi-Nezhad N, Missault S, Notario-Reinoso A, Hassani A, Amiri M, Keliris GA. The impact of selective and non-selective medial septum stimulation on hippocampal neuronal oscillations: A study based on modeling and experiments. Neurobiol Dis 2023; 180:106052. [PMID: 36822547 DOI: 10.1016/j.nbd.2023.106052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 02/09/2023] [Accepted: 02/19/2023] [Indexed: 02/23/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder with a rising socioeconomic impact on societies. The hippocampus (HPC), which plays an important role in AD, is affected in the early stages. The medial septum (MS) in the forebrain provides major cholinergic input to the HPC and has been shown to play a significant role in generating oscillations in hippocampal neurons. Cholinergic neurons in the basal forebrain are particularly vulnerable to neurodegeneration in AD. To better understand the role of MS neurons including the cholinergic, glutamatergic, and GABAergic subpopulations in generating the well-known brain rhythms in HPC including delta, theta, slow gamma, and fast gamma oscillations, we designed a detailed computational model of the septohippocampal pathway. We validated the results of our model, using electrophysiological recordings in HPC with and without stimulation of the cholinergic neurons in MS using designer receptors exclusively activated by designer drugs (DREADDs) in healthy male ChAT-cre rats. Then, we eliminated 75% of the MS cholinergic neurons in the model to simulate degeneration in AD. A series of selective and non-selective stimulations of the remaining MS neurons were performed to understand the dynamics of oscillation regulation in the HPC during the degenerated state. In this way, appropriate stimulation strategies able to normalize the aberrant oscillations are proposed. We found that selectively stimulating the remaining healthy cholinergic neurons was sufficient for network recovery and compare this to stimulating other subpopulations and a non-selective stimulation of all MS neurons. Our data provide valuable information for the development of new therapeutic strategies in AD and a tool to test and predict the outcome of potential theranostic manipulations.
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Affiliation(s)
- Nima Salimi-Nezhad
- Medical Biology Research Center, Institute of Health Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | | | - Anaïs Notario-Reinoso
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
| | - Atefe Hassani
- Medical Technology Research Center, Institute of Health Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mahmood Amiri
- Medical Technology Research Center, Institute of Health Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Georgios A Keliris
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; Institute of Computer Science, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece.
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12
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Griguoli M, Pimpinella D. Medial septum: relevance for social memory. Front Neural Circuits 2022; 16:965172. [PMID: 36082110 PMCID: PMC9445153 DOI: 10.3389/fncir.2022.965172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Animal species are named social when they develop the capability of complex behaviors based on interactions with conspecifics that include communication, aggression, mating and parental behavior, crucial for well-being and survival. The underpinning of such complex behaviors is social memory, namely the capacity to discriminate between familiar and novel individuals. The Medial Septum (MS), a region localized in the basal forebrain, is part of the brain network involved in social memory formation. MS receives several cortical and subcortical synaptic and neuromodulatory inputs that make it an important hub in processing social information relevant for social memory. Particular attention is paid to synaptic inputs that control both the MS and the CA2 region of the hippocampus, one of the major MS output, that has been causally linked to social memory. In this review article, we will provide an overview of local and long range connectivity that allows MS to integrate and process social information. Furthermore, we will summarize previous strategies used to determine how MS controls social memory in different animal species. Finally, we will discuss the impact of an altered MS signaling on social memory in animal models and patients affected by neurodevelopmental and neurodegenerative disorders, including autism and Alzheimer’s Disease.
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Affiliation(s)
- Marilena Griguoli
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
- Institute of Molecular Biology and Pathology of the National Council of Research (IBPM-CNR), Rome, Italy
- *Correspondence: Marilena Griguoli
| | - Domenico Pimpinella
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
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13
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Tukker JJ, Beed P, Brecht M, Kempter R, Moser EI, Schmitz D. Microcircuits for spatial coding in the medial entorhinal cortex. Physiol Rev 2022; 102:653-688. [PMID: 34254836 PMCID: PMC8759973 DOI: 10.1152/physrev.00042.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The hippocampal formation is critically involved in learning and memory and contains a large proportion of neurons encoding aspects of the organism's spatial surroundings. In the medial entorhinal cortex (MEC), this includes grid cells with their distinctive hexagonal firing fields as well as a host of other functionally defined cell types including head direction cells, speed cells, border cells, and object-vector cells. Such spatial coding emerges from the processing of external inputs by local microcircuits. However, it remains unclear exactly how local microcircuits and their dynamics within the MEC contribute to spatial discharge patterns. In this review we focus on recent investigations of intrinsic MEC connectivity, which have started to describe and quantify both excitatory and inhibitory wiring in the superficial layers of the MEC. Although the picture is far from complete, it appears that these layers contain robust recurrent connectivity that could sustain the attractor dynamics posited to underlie grid pattern formation. These findings pave the way to a deeper understanding of the mechanisms underlying spatial navigation and memory.
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Affiliation(s)
- John J Tukker
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
| | - Prateep Beed
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humbold-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Brecht
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
- Neurocure Cluster of Excellence, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Richard Kempter
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Edvard I Moser
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Dietmar Schmitz
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humbold-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- Neurocure Cluster of Excellence, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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14
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Burjanadze MA, Dashniani MG, Solomonia RO, Beselia GV, Tsverava L, Lagani V, Chkhikvishvili NC, Naneishvili TL, Kruashvili LB, Chighladze MR. Age-related changes in medial septal cholinergic and GABAergic projection neurons and hippocampal neurotransmitter receptors: relationship with memory impairment. Exp Brain Res 2022; 240:1589-1604. [PMID: 35357523 DOI: 10.1007/s00221-022-06354-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/21/2022] [Indexed: 11/24/2022]
Abstract
The hippocampus, which provides cognitive functions, has been shown to become highly vulnerable during aging. One important modulator of the hippocampal neural network is the medial septum (MS). The present study attempts to determine how age-related mnemonic dysfunction is associated with neurochemical changes in the septohippocampal (SH) system, using behavioral and immunochemical experiments performed on young-adult, middle-aged and aged rats. According to these behavioral results, the aged and around 52.8% of middle-aged rats (within the "middle-aged-impaired" sub-group) showed both impaired spatial reference memory in the Morris water maze and habituation in the open field. Immunohistochemical studies revealed a significant decrease in the number of MS choline acetyltransferase immunoreactive cells in the aged and all middle-aged rats, in comparison to the young; however the number of gamma-aminobutyric acid-ergic (GABAergic) parvalbumin immunoreactive cells was higher in middle-aged-impaired and older rats compared to young and middle-aged-unimpaired rats. Western Blot analysis moreover showed a decrease in the level of expression of cholinergic, GABAergic and glutamatergic receptors in the hippocampus of middle-aged-impaired and aged rats in contrast to middle-aged-unimpaired and young rats. The present results demonstrate for the first time that a decrease in the expression level of hippocampal receptors in naturally aged rats with impaired cognitive abilities occurs in parallel with an increase in the number of GABAergic neurons in the MS, and it highlights the particular importance of inhibitory signaling in the SH network for memory function.
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Affiliation(s)
- Maia A Burjanadze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.
| | - Manana G Dashniani
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Revaz O Solomonia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.,Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Gela V Beselia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.,Department of Physiology and Pharmacology, Petre Shotadze Tbilisi Medical Academy, 0144, Tbilisi, Georgia
| | - Lia Tsverava
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.,Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Vincenzo Lagani
- Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Nino C Chkhikvishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Temur L Naneishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Lali B Kruashvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Mariam R Chighladze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
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15
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Mysin I, Shubina L. From mechanisms to functions: The role of theta and gamma coherence in the intrahippocampal circuits. Hippocampus 2022; 32:342-358. [PMID: 35192228 DOI: 10.1002/hipo.23410] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 11/08/2022]
Abstract
Brain rhythms are essential for information processing in neuronal networks. Oscillations recorded in different brain regions can be synchronized and have a constant phase difference, that is, they can be coherent. Coherence between local field potential (LFP) signals from different brain regions may be correlated with the performance of cognitive tasks, indicating that these regions of the brain are jointly involved in the information processing. Why does coherence occur and how is it related to the information transfer between different regions of the hippocampal formation? In this article, we discuss possible mechanisms of theta and gamma coherence and its role in the hippocampus-dependent attention and memory processes, since theta and gamma rhythms are most pronounced in these processes. We review in vivo studies of interactions between different regions of the hippocampal formation in theta and gamma frequency bands. The key propositions of the review are as follows: (1) coherence emerges from synchronous postsynaptic currents in principal neurons as a result of synchronization of neuronal spike activity; (2) the synchronization of neuronal spike patterns in two regions of the hippocampal formation can be realized through induction or resonance; (3) coherence at a specific time point reflects the transfer of information between the regions of the hippocampal formation; (4) the physiological roles of theta and gamma coherence are different due to their different functions and mechanisms of generation. All hippocampal neurons are involved in theta activity, and theta coherence arranges the firing order of principal neurons throughout the hippocampal formation. In contrast, gamma coherence reflects the coupling of active neuronal ensembles. Overall, the coherence of LFPs between different areas of the brain is an important physiological process based on the synchronized neuronal firing, and it is essential for cooperative information processing.
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Affiliation(s)
- Ivan Mysin
- Laboratory of Systemic Organization of Neurons, Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
| | - Liubov Shubina
- Laboratory of Systemic Organization of Neurons, Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation
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16
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Vandrey B, Armstrong J, Brown CM, Garden DLF, Nolan MF. Fan cells in lateral entorhinal cortex directly influence medial entorhinal cortex through synaptic connections in layer 1. eLife 2022; 11:83008. [PMID: 36562467 PMCID: PMC9822265 DOI: 10.7554/elife.83008] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Standard models for spatial and episodic memory suggest that the lateral entorhinal cortex (LEC) and medial entorhinal cortex (MEC) send parallel independent inputs to the hippocampus, each carrying different types of information. Here, we evaluate the possibility that information is integrated between divisions of the entorhinal cortex prior to reaching the hippocampus. We demonstrate that, in mice, fan cells in layer 2 (L2) of LEC that receive neocortical inputs, and that project to the hippocampal dentate gyrus, also send axon collaterals to layer 1 (L1) of the MEC. Activation of inputs from fan cells evokes monosynaptic glutamatergic excitation of stellate and pyramidal cells in L2 of the MEC, typically followed by inhibition that contains fast and slow components mediated by GABAA and GABAB receptors, respectively. Inputs from fan cells also directly activate interneurons in L1 and L2 of MEC, with synaptic connections from L1 interneurons accounting for slow feedforward inhibition of L2 principal cell populations. The relative strength of excitation and inhibition following fan cell activation differs substantially between neurons and is largely independent of anatomical location. Our results demonstrate that the LEC, in addition to directly influencing the hippocampus, can activate or inhibit major hippocampal inputs arising from the MEC. Thus, local circuits in the superficial MEC may combine spatial information with sensory and higher order signals from the LEC, providing a substrate for integration of 'what' and 'where' components of episodic memories.
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Affiliation(s)
- Brianna Vandrey
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Jack Armstrong
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Christina M Brown
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Derek LF Garden
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom,Simons Initiative for the Developing Brain, University of EdinburghEdinburghUnited Kingdom,Centre for Statistics, University of EdinburghEdinburghUnited Kingdom
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17
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Quirk CR, Zutshi I, Srikanth S, Fu ML, Marciano ND, Wright MK, Parsey DF, Liu S, Siretskiy RE, Huynh TL, Leutgeb JK, Leutgeb S. Precisely timed theta oscillations are selectively required during the encoding phase of memory. Nat Neurosci 2021; 24:1614-1627. [PMID: 34608335 PMCID: PMC8556344 DOI: 10.1038/s41593-021-00919-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 08/02/2021] [Indexed: 11/12/2022]
Abstract
Brain oscillations have been hypothesized to support cognitive function by coordinating spike timing within and across brain regions, yet it is often not known when timing is either critical for neural computations or an epiphenomenon. The entorhinal cortex and hippocampus are necessary for learning and memory and exhibit prominent theta oscillations (6-9 Hz), which are controlled by pacemaker cells in the medial septal area. Here we show that entorhinal and hippocampal neuronal activity patterns were strongly entrained by rhythmic optical stimulation of parvalbumin-positive medial septal area neurons in mice. Despite strong entrainment, memory impairments in a spatial working memory task were not observed with pacing frequencies at or below the endogenous theta frequency and only emerged at frequencies ≥10 Hz, and specifically when pacing was targeted to maze segments where encoding occurs. Neural computations during the encoding phase were therefore selectively disrupted by perturbations of the timing of neuronal firing patterns.
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Affiliation(s)
- Clare R. Quirk
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ipshita Zutshi
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sunandha Srikanth
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Maylin L. Fu
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Naomie Devico Marciano
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Morgan K. Wright
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Darian F. Parsey
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stanley Liu
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rachel E. Siretskiy
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tiffany L. Huynh
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jill K. Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stefan Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, CA 92093, USA,Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093, USA,Correspondence should be addressed to S.L. ()
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18
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Robinson JC, Brandon MP. Skipping ahead: A circuit for representing the past, present, and future. eLife 2021; 10:e68795. [PMID: 34647521 PMCID: PMC8516414 DOI: 10.7554/elife.68795] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 09/28/2021] [Indexed: 01/02/2023] Open
Abstract
Envisioning the future is intuitively linked to our ability to remember the past. Within the memory system, substantial work has demonstrated the involvement of the prefrontal cortex and the hippocampus in representing the past and present. Recent data shows that both the prefrontal cortex and the hippocampus encode future trajectories, which are segregated in time by alternating cycles of the theta rhythm. Here, we discuss how information is temporally organized by these brain regions supported by the medial septum, nucleus reuniens, and parahippocampal regions. Finally, we highlight a brain circuit that we predict is essential for the temporal segregation of future scenarios.
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Affiliation(s)
- Jennifer C Robinson
- Department of Psychological and Brain Sciences, Rajen Kilachand Center for Integrated Life Sciences and Engineering, Boston UniversityBostonUnited States
| | - Mark P Brandon
- Department of Psychiatry, Douglas Hospital Research Centre, McGill UniversityMontrealCanada
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19
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Badrinarayanan S, Manseau F, Williams S, Brandon MP. A Characterization of the Electrophysiological and Morphological Properties of Vasoactive Intestinal Peptide (VIP) Interneurons in the Medial Entorhinal Cortex (MEC). Front Neural Circuits 2021; 15:653116. [PMID: 34421547 PMCID: PMC8378838 DOI: 10.3389/fncir.2021.653116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 06/28/2021] [Indexed: 11/27/2022] Open
Abstract
Circuit interactions within the medial entorhinal cortex (MEC) translate movement into a coherent code for spatial location. Entorhinal principal cells are subject to strong lateral inhibition, suggesting that a disinhibitory mechanism may drive their activation. Cortical Vasoactive Intestinal Peptide (VIP) expressing inhibitory neurons are known to contact other interneurons and excitatory cells and are thus capable of providing a local disinhibitory mechanism, yet little is known about this cell type in the MEC. To investigate the electrophysiological and morphological properties of VIP cells in the MEC, we use in vitro whole-cell patch-clamp recordings in VIPcre/tdTom mice. We report several gradients in electrophysiological properties of VIP cells that differ across laminae and along the dorsal-ventral MEC axis. We additionally show that VIP cells have distinct morphological features across laminae. Together, these results characterize the cellular and morphological properties of VIP cells in the MEC.
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Affiliation(s)
- Saishree Badrinarayanan
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Frédéric Manseau
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal, QC, Canada
| | - Sylvain Williams
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Mark P Brandon
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
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20
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Mocellin P, Mikulovic S. The Role of the Medial Septum-Associated Networks in Controlling Locomotion and Motivation to Move. Front Neural Circuits 2021; 15:699798. [PMID: 34366795 PMCID: PMC8340000 DOI: 10.3389/fncir.2021.699798] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 06/28/2021] [Indexed: 12/29/2022] Open
Abstract
The Medial Septum and diagonal Band of Broca (MSDB) was initially studied for its role in locomotion. However, the last several decades were focussed on its intriguing function in theta rhythm generation. Early studies relied on electrical stimulation, lesions and pharmacological manipulation, and reported an inconclusive picture regarding the role of the MSDB circuits. Recent studies using more specific methodologies have started to elucidate the differential role of the MSDB's specific cell populations in controlling both theta rhythm and behaviour. In particular, a novel theory is emerging showing that different MSDB's cell populations project to different brain regions and control distinct aspects of behaviour. While the majority of these behaviours involve movement, increasing evidence suggests that MSDB-related networks govern the motivational aspect of actions, rather than locomotion per se. Here, we review the literature that links MSDB, theta activity, and locomotion and propose open questions, future directions, and methods that could be employed to elucidate the diverse roles of the MSDB-associated networks.
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Affiliation(s)
- Petra Mocellin
- Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
- International Max Planck Research School for Brain and Behavior, Bonn, Germany
| | - Sanja Mikulovic
- Research Group Cognition and Emotion, Leibniz Institute for Neurobiology, Magdeburg, Germany
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21
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Hristova K, Martinez-Gonzalez C, Watson TC, Codadu NK, Hashemi K, Kind PC, Nolan MF, Gonzalez-Sulser A. Medial septal GABAergic neurons reduce seizure duration upon optogenetic closed-loop stimulation. Brain 2021; 144:1576-1589. [PMID: 33769452 PMCID: PMC8219369 DOI: 10.1093/brain/awab042] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/16/2020] [Accepted: 12/06/2020] [Indexed: 11/22/2022] Open
Abstract
Seizures can emerge from multiple or large foci in temporal lobe epilepsy, complicating focally targeted strategies such as surgical resection or the modulation of the activity of specific hippocampal neuronal populations through genetic or optogenetic techniques. Here, we evaluate a strategy in which optogenetic activation of medial septal GABAergic neurons, which provide extensive projections throughout the hippocampus, is used to control seizures. We utilized the chronic intrahippocampal kainate mouse model of temporal lobe epilepsy, which results in spontaneous seizures and as is often the case in human patients, presents with hippocampal sclerosis. Medial septal GABAergic neuron populations were immunohistochemically labelled and were not reduced in epileptic conditions. Genetic labelling with mRuby of medial septal GABAergic neuron synaptic puncta and imaging across the rostral to caudal extent of the hippocampus, also indicated an unchanged number of putative synapses in epilepsy. Furthermore, optogenetic stimulation of medial septal GABAergic neurons consistently modulated oscillations across multiple hippocampal locations in control and epileptic conditions. Finally, wireless optogenetic stimulation of medial septal GABAergic neurons, upon electrographic detection of spontaneous hippocampal seizures, resulted in reduced seizure durations. We propose medial septal GABAergic neurons as a novel target for optogenetic control of seizures in temporal lobe epilepsy.
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Affiliation(s)
- Katerina Hristova
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Cristina Martinez-Gonzalez
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Thomas C Watson
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Neela K Codadu
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | | | - Peter C Kind
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Alfredo Gonzalez-Sulser
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
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22
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Theta Oscillations Gate the Transmission of Reliable Sequences in the Medial Entorhinal Cortex. eNeuro 2021; 8:ENEURO.0059-20.2021. [PMID: 33820802 PMCID: PMC8208650 DOI: 10.1523/eneuro.0059-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 11/21/2022] Open
Abstract
Stability and precision of sequential activity in the entorhinal cortex (EC) is crucial for encoding spatially guided behavior and memory. These sequences are driven by constantly evolving sensory inputs and persist despite a noisy background. In a realistic computational model of a medial EC (MEC) microcircuit, we show that intrinsic neuronal properties and network mechanisms interact with theta oscillations to generate reliable outputs. In our model, sensory inputs activate interneurons near their most excitable phase during each theta cycle. As the inputs change, different interneurons are recruited and postsynaptic stellate cells are released from inhibition. This causes a sequence of rebound spikes. The rebound time scale of stellate cells, because of an h–current, matches that of theta oscillations. This fortuitous similarity of time scales ensures that stellate spikes get relegated to the least excitable phase of theta and the network encodes the external drive but ignores recurrent excitation. In contrast, in the absence of theta, rebound spikes compete with external inputs and disrupt the sequence that follows. Further, the same mechanism where theta modulates the gain of incoming inputs, can be used to select between competing inputs to create transient functionally connected networks. Our results concur with experimental data that show, subduing theta oscillations disrupts the spatial periodicity of grid cell receptive fields. In the bat MEC where grid cell receptive fields persist even in the absence of continuous theta oscillations, we argue that other low frequency fluctuations play the role of theta.
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23
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Lepperød ME, Christensen AC, Lensjø KK, Buccino AP, Yu J, Fyhn M, Hafting T. Optogenetic pacing of medial septum parvalbumin-positive cells disrupts temporal but not spatial firing in grid cells. SCIENCE ADVANCES 2021; 7:7/19/eabd5684. [PMID: 33952512 DOI: 10.1126/sciadv.abd5684] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Grid cells in the medial entorhinal cortex (MEC) exhibit remarkable spatial activity patterns with spikes coordinated by theta oscillations driven by the medial septal area (MSA). Spikes from grid cells progress relative to the theta phase in a phenomenon called phase precession, which is suggested as essential to create the spatial periodicity of grid cells. Here, we show that optogenetic activation of parvalbumin-positive (PV+) cells in the MSA enabled selective pacing of local field potential (LFP) oscillations in MEC. During optogenetic stimulation, the grid cells were locked to the imposed pacing frequency but kept their spatial patterns. Phase precession was abolished, and speed information was no longer reflected in the LFP oscillations but was still carried by rate coding of individual MEC neurons. Together, these results support that theta oscillations are not critical to the spatial pattern of grid cells and do not carry a crucial velocity signal.
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Affiliation(s)
- Mikkel Elle Lepperød
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Ane Charlotte Christensen
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
| | - Kristian Kinden Lensjø
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Alessio Paolo Buccino
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Jai Yu
- Department of Psychology, Institute for Mind and Biology, Grossman Institute for Neuroscience, and Quantitative Biology and Human Behavior, University of Chicago, 5848 S. University Avenue, Chicago, IL 60637, USA
| | - Marianne Fyhn
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Torkel Hafting
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway
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24
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Villar PS, Hu R, Araneda RC. Long-Range GABAergic Inhibition Modulates Spatiotemporal Dynamics of the Output Neurons in the Olfactory Bulb. J Neurosci 2021; 41:3610-3621. [PMID: 33687961 PMCID: PMC8055075 DOI: 10.1523/jneurosci.1498-20.2021] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 11/21/2022] Open
Abstract
Local interneurons of the olfactory bulb (OB) are densely innervated by long-range GABAergic neurons from the basal forebrain (BF), suggesting that this top-down inhibition regulates early processing in the olfactory system. However, how GABAergic inputs modulate the OB output neurons, the mitral/tufted cells, is unknown. Here, in male and female mice acute brain slices, we show that optogenetic activation of BF GABAergic inputs produced distinct local circuit effects that can influence the activity of mitral/tufted cells in the spatiotemporal domains. Activation of the GABAergic axons produced a fast disinhibition of mitral/tufted cells consistent with a rapid and synchronous release of GABA onto local interneurons in the glomerular and inframitral circuits of the OB, which also reduced the spike precision of mitral/tufted cells in response to simulated stimuli. In addition, BF GABAergic inhibition modulated local oscillations in a layer-specific manner. The intensity of locally evoked θ oscillations was decreased on activation of top-down inhibition in the glomerular circuit, while evoked γ oscillations were reduced by inhibition of granule cells. Furthermore, BF GABAergic input reduced dendrodendritic inhibition in mitral/tufted cells. Together, these results suggest that long-range GABAergic neurons from the BF are well suited to influence temporal and spatial aspects of processing by OB circuits.SIGNIFICANCE STATEMENT Disruption of GABAergic inhibition from the basal forebrain (BF) to the olfactory bulb (OB) impairs the discrimination of similar odors, yet how this centrifugal inhibition influences neuronal circuits in the OB remains unclear. Here, we show that the BF GABAergic neurons exclusively target local inhibitory neurons in the OB, having a functional disinhibitory effect on the output neurons, the mitral cells. Phasic inhibition by BF GABAergic neurons reduces spike precision of mitral cells and lowers the intensity of oscillatory activity in the OB, while directly modulating the extent of dendrodendritic inhibition. These circuit-level effects of this centrifugal inhibition can influence the temporal and spatial dynamics of odor coding in the OB.
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Affiliation(s)
- Pablo S Villar
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | - Ruilong Hu
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | - Ricardo C Araneda
- Department of Biology, University of Maryland, College Park, Maryland 20742
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25
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Kurikawa T, Mizuseki K, Fukai T. Oscillation-Driven Memory Encoding, Maintenance, and Recall in an Entorhinal-Hippocampal Circuit Model. Cereb Cortex 2021; 31:2038-2057. [PMID: 33230536 DOI: 10.1093/cercor/bhaa343] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/15/2020] [Accepted: 10/22/2020] [Indexed: 11/14/2022] Open
Abstract
During the execution of working memory tasks, task-relevant information is processed by local circuits across multiple brain regions. How this multiarea computation is conducted by the brain remains largely unknown. To explore such mechanisms in spatial working memory, we constructed a neural network model involving parvalbumin-positive, somatostatin-positive, and vasoactive intestinal polypeptide-positive interneurons in the hippocampal CA1 and the superficial and deep layers of medial entorhinal cortex (MEC). Our model is based on a hypothesis that cholinergic modulations differently regulate information flows across CA1 and MEC at memory encoding, maintenance, and recall during delayed nonmatching-to-place tasks. In the model, theta oscillation coordinates the proper timing of interactions between these regions. Furthermore, the model predicts that MEC is engaged in decoding as well as encoding spatial memory, which we confirmed by experimental data analysis. Thus, our model accounts for the neurobiological characteristics of the cross-area information routing underlying working memory tasks.
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Affiliation(s)
- Tomoki Kurikawa
- Department of Physics, Kansai Medical University, Hirakata, Osaka 573-1191, Japan
| | - Kenji Mizuseki
- Department of Physiology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka 545-8585, Japan
| | - Tomoki Fukai
- Okinawa Institute of Science and Technology, Onna-son, Okinawa 904-0495, Japan.,RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
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26
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Schlesiger MI, Ruff T, MacLaren DAA, Barriuso-Ortega I, Saidov KM, Yen TY, Monyer H. Two septal-entorhinal GABAergic projections differentially control coding properties of spatially tuned neurons in the medial entorhinal cortex. Cell Rep 2021; 34:108801. [PMID: 33657367 DOI: 10.1016/j.celrep.2021.108801] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 12/23/2020] [Accepted: 02/05/2021] [Indexed: 12/20/2022] Open
Abstract
Septal parvalbumin-expressing (PV+) and calbindin-expressing (CB+) projections inhibit low-threshold and fast-spiking interneurons, respectively, in the medial entorhinal cortex (MEC). We investigate how the two inputs control neuronal activity in the MEC in freely moving mice. Stimulation of PV+ and CB+ terminals causes disinhibition of spatially tuned MEC neurons, but exerts differential effects on temporal coding and burst firing. Thus, recruitment of PV+ projections disrupts theta-rhythmic firing of MEC neurons, while stimulation of CB+ projections increases burst firing of grid cells and enhances phase precession in a cell-type-specific manner. Inactivation of septal PV+ or CB+ neurons differentially affects context, reference, and working memory. Together, our results reveal how specific connectivity of septal GABAergic projections with MEC interneurons translates into differential modulation of MEC neuronal coding.
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Affiliation(s)
- Magdalene Isabell Schlesiger
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Tobias Ruff
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Duncan Archibald Allan MacLaren
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Isabel Barriuso-Ortega
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Khalid Magomedovich Saidov
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ting-Yun Yen
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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27
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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 PMCID: PMC7795765 DOI: 10.3390/ijms22010400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [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.
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Affiliation(s)
- Kazuya Matsuo
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; (K.M.); (Y.Y.)
| | - Yasushi Yabuki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; (K.M.); (Y.Y.)
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Ronald Melki
- Laboratory of Neurodegenerative Diseases, CEA, Institut François Jacob (MIRcen) and CNRS, 18 Route du Panorama, 92265 Fontenay-aux-Roses, France; (R.M.); (L.B.)
| | - Luc Bousset
- Laboratory of Neurodegenerative Diseases, CEA, Institut François Jacob (MIRcen) and CNRS, 18 Route du Panorama, 92265 Fontenay-aux-Roses, France; (R.M.); (L.B.)
| | - Yuji Owada
- Department of Organ Anatomy, Graduate School of Medicine, Tohoku University, Sendai 980-0872, Japan;
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; (K.M.); (Y.Y.)
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28
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CaMKIIα-Positive Interneurons Identified via a microRNA-Based Viral Gene Targeting Strategy. J Neurosci 2020; 40:9576-9588. [PMID: 33158963 DOI: 10.1523/jneurosci.2570-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/08/2023] Open
Abstract
Single-cell analysis is revealing increasing diversity in gene expression profiles among brain cells. Traditional promotor-based viral gene expression techniques, however, cannot capture the growing variety among single cells. We demonstrate a novel viral gene expression strategy to target cells with specific miRNA expression using miRNA-guided neuron tags (mAGNET). We designed mAGNET viral vectors containing a CaMKIIα promoter and microRNA-128 (miR-128) binding sites, and labeled CaMKIIα+ cells with naturally low expression of miR-128 (Lm128C cells) in male and female mice. Although CaMKIIα has traditionally been considered as an excitatory neuron marker, our single-cell sequencing results reveal that Lm128C cells are CaMKIIα+ inhibitory neurons of parvalbumin or somatostatin subtypes. Further evaluation of the physiological properties of Lm128C cell in brain slices showed that Lm128C cells exhibit elevated membrane excitability, with biophysical properties closely resembling those of fast-spiking interneurons, consistent with previous transcriptomic findings of miR-128 in regulating gene networks that govern membrane excitability. To further demonstrate the utility of this new viral expression strategy, we expressed GCaMP6f in Lm128C cells in the superficial layers of the motor cortex and performed in vivo calcium imaging in mice during locomotion. We found that Lm128C cells exhibit elevated calcium event rates and greater intrapopulation correlation than the overall CaMKIIα+ cells during movement. In summary, the miRNA-based viral gene targeting strategy described here allows us to label a sparse population of CaMKIIα+ interneurons for functional studies, providing new capabilities to investigate the relationship between gene expression and physiological properties in the brain.SIGNIFICANCE STATEMENT We report the discovery of a class of CaMKIIα+ cortical interneurons, labeled via a novel miRNA-based viral gene targeting strategy, combinatorial to traditional promoter-based strategies. The fact that we found a small, yet distinct, population of cortical inhibitory neurons that express CaMKIIα demonstrates that CaMKIIα is not as specific for excitatory neurons as commonly believed. As single-cell sequencing tools are providing increasing insights into the gene expression diversity of neurons, including miRNA profile data, we expect that the miRNA-based gene targeting strategy presented here can help delineate many neuron populations whose physiological properties can be readily related to the miRNA gene regulatory networks.
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29
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Katyare N, Sikdar SK. Theta resonance and synaptic modulation scale activity patterns in the medial entorhinal cortex stellate cells. Ann N Y Acad Sci 2020; 1478:92-112. [PMID: 32794193 DOI: 10.1111/nyas.14434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 05/31/2020] [Accepted: 06/19/2020] [Indexed: 11/28/2022]
Abstract
Stellate cells (SCs) of the medial entorhinal cortex (MEC) are rich in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are known to effectively shape their activity patterns. The explanatory mechanisms, however, have remained elusive. One important but previously unassessed possibility is that HCN channels control the gain of synaptic inputs to these cells. Here, we test this possibility in rat brain slices, while subjecting SCs to a stochastic synaptic bombardment using the dynamic clamp. We show that in the presence of synaptic noise, HCN channels mainly exert their influence by increasing the relative signal gain in the theta frequency through the theta modulation of stochastic synaptic inputs. This subthreshold synaptic modulation then translates into a spiking resonance, which steepens with excitation in the presence of HCN channels. We present here a systematic assessment of synaptic theta modulation and trace its implications to the suprathreshold control of firing rate motifs. Such analysis was yet lacking in the SC literature. Furthermore, we assess the impact of noise statistics on this gain modulation and indicate possible mechanisms for the emergence of membrane theta oscillations and synaptic ramps, as observed in vivo. We support the data with a computational model that further unveils a competing role of inhibition, suggesting important implications for MEC computations.
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Affiliation(s)
- Nupur Katyare
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Sujit Kumar Sikdar
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka, India
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30
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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: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [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.
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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.
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31
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Tukker JJ, Beed P, Schmitz D, Larkum ME, Sachdev RNS. Up and Down States and Memory Consolidation Across Somatosensory, Entorhinal, and Hippocampal Cortices. Front Syst Neurosci 2020; 14:22. [PMID: 32457582 PMCID: PMC7227438 DOI: 10.3389/fnsys.2020.00022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/03/2020] [Indexed: 01/01/2023] Open
Abstract
In the course of a day, brain states fluctuate, from conscious awake information-acquiring states to sleep states, during which previously acquired information is further processed and stored as memories. One hypothesis is that memories are consolidated and stored during "offline" states such as sleep, a process thought to involve transfer of information from the hippocampus to other cortical areas. Up and Down states (UDS), patterns of activity that occur under anesthesia and sleep states, are likely to play a role in this process, although the nature of this role remains unclear. Here we review what is currently known about these mechanisms in three anatomically distinct but interconnected cortical areas: somatosensory cortex, entorhinal cortex, and the hippocampus. In doing so, we consider the role of this activity in the coordination of "replay" during sleep states, particularly during hippocampal sharp-wave ripples. We conclude that understanding the generation and propagation of UDS may provide key insights into the cortico-hippocampal dialogue linking archi- and neocortical areas during memory formation.
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Affiliation(s)
- John J Tukker
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Prateep Beed
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,Cluster of Excellence NeuroCure, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Matthew E Larkum
- Cluster of Excellence NeuroCure, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany.,Institut für Biologie, Humboldt Universität, Berlin, Germany
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32
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Pastoll H, Garden DL, Papastathopoulos I, Sürmeli G, Nolan MF. Inter- and intra-animal variation in the integrative properties of stellate cells in the medial entorhinal cortex. eLife 2020; 9:52258. [PMID: 32039761 PMCID: PMC7067584 DOI: 10.7554/elife.52258] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/04/2020] [Indexed: 01/28/2023] Open
Abstract
Distinctions between cell types underpin organizational principles for nervous system function. Functional variation also exists between neurons of the same type. This is exemplified by correspondence between grid cell spatial scales and the synaptic integrative properties of stellate cells (SCs) in the medial entorhinal cortex. However, we know little about how functional variability is structured either within or between individuals. Using ex-vivo patch-clamp recordings from up to 55 SCs per mouse, we found that integrative properties vary between mice and, in contrast to the modularity of grid cell spatial scales, have a continuous dorsoventral organization. Our results constrain mechanisms for modular grid firing and provide evidence for inter-animal phenotypic variability among neurons of the same type. We suggest that neuron type properties are tuned to circuit-level set points that vary within and between animals.
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Affiliation(s)
- Hugh Pastoll
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Derek L Garden
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ioannis Papastathopoulos
- The Alan Turing Institute, London, United States.,School of Mathematics, Maxwell Institute and Centre for Statistics, University of Edinburgh, Edinburgh, United Kingdom
| | - Gülşen Sürmeli
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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33
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Kang L, DeWeese MR. Replay as wavefronts and theta sequences as bump oscillations in a grid cell attractor network. eLife 2019; 8:46351. [PMID: 31736462 PMCID: PMC6901334 DOI: 10.7554/elife.46351] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 11/15/2019] [Indexed: 11/17/2022] Open
Abstract
Grid cells fire in sequences that represent rapid trajectories in space. During locomotion, theta sequences encode sweeps in position starting slightly behind the animal and ending ahead of it. During quiescence and slow wave sleep, bouts of synchronized activity represent long trajectories called replays, which are well-established in place cells and have been recently reported in grid cells. Theta sequences and replay are hypothesized to facilitate many cognitive functions, but their underlying mechanisms are unknown. One mechanism proposed for grid cell formation is the continuous attractor network. We demonstrate that this established architecture naturally produces theta sequences and replay as distinct consequences of modulating external input. Driving inhibitory interneurons at the theta frequency causes attractor bumps to oscillate in speed and size, which gives rise to theta sequences and phase precession, respectively. Decreasing input drive to all neurons produces traveling wavefronts of activity that are decoded as replays.
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Affiliation(s)
- Louis Kang
- Redwood Center for Theoretical Neuroscience, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States
| | - Michael R DeWeese
- Redwood Center for Theoretical Neuroscience, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States
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34
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Mysin IE, Kitchigina VF, Kazanovich YB. Phase relations of theta oscillations in a computer model of the hippocampal CA1 field: Key role of Schaffer collaterals. Neural Netw 2019; 116:119-138. [DOI: 10.1016/j.neunet.2019.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 03/29/2019] [Accepted: 04/02/2019] [Indexed: 02/04/2023]
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35
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GABAergic Medial Septal Neurons with Low-Rhythmic Firing Innervating the Dentate Gyrus and Hippocampal Area CA3. J Neurosci 2019; 39:4527-4549. [PMID: 30926750 PMCID: PMC6554630 DOI: 10.1523/jneurosci.3024-18.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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.
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36
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Savelli F, Knierim JJ. Origin and role of path integration in the cognitive representations of the hippocampus: computational insights into open questions. J Exp Biol 2019; 222:jeb188912. [PMID: 30728236 PMCID: PMC7375830 DOI: 10.1242/jeb.188912] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Path integration is a straightforward concept with varied connotations that are important to different disciplines concerned with navigation, such as ethology, cognitive science, robotics and neuroscience. In studying the hippocampal formation, it is fruitful to think of path integration as a computation that transforms a sense of motion into a sense of location, continuously integrated with landmark perception. Here, we review experimental evidence that path integration is intimately involved in fundamental properties of place cells and other spatial cells that are thought to support a cognitive abstraction of space in this brain system. We discuss hypotheses about the anatomical and computational origin of path integration in the well-characterized circuits of the rodent limbic system. We highlight how computational frameworks for map-building in robotics and cognitive science alike suggest an essential role for path integration in the creation of a new map in unfamiliar territory, and how this very role can help us make sense of differences in neurophysiological data from novel versus familiar and small versus large environments. Similar computational principles could be at work when the hippocampus builds certain non-spatial representations, such as time intervals or trajectories defined in a sensory stimulus space.
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Affiliation(s)
- Francesco Savelli
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - James J Knierim
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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37
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Campbell MG, Giocomo LM. Self-motion processing in visual and entorhinal cortices: inputs, integration, and implications for position coding. J Neurophysiol 2018; 120:2091-2106. [PMID: 30089025 PMCID: PMC6230811 DOI: 10.1152/jn.00686.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 01/12/2023] Open
Abstract
The sensory signals generated by self-motion are complex and multimodal, but the ability to integrate these signals into a unified self-motion percept to guide navigation is essential for animal survival. Here, we summarize classic and recent work on self-motion coding in the visual and entorhinal cortices of the rodent brain. We compare motion processing in rodent and primate visual cortices, highlighting the strengths of classic primate work in establishing causal links between neural activity and perception, and discuss the integration of motor and visual signals in rodent visual cortex. We then turn to the medial entorhinal cortex (MEC), where calculations using self-motion to update position estimates are thought to occur. We focus on several key sources of self-motion information to MEC: the medial septum, which provides locomotor speed information; visual cortex, whose input has been increasingly recognized as essential to both position and speed-tuned MEC cells; and the head direction system, which is a major source of directional information for self-motion estimates. These inputs create a large and diverse group of self-motion codes in MEC, and great interest remains in how these self-motion codes might be integrated by MEC grid cells to estimate position. However, which signals are used in these calculations and the mechanisms by which they are integrated remain controversial. We end by proposing future experiments that could further our understanding of the interactions between MEC cells that code for self-motion and position and clarify the relationship between the activity of these cells and spatial perception.
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Affiliation(s)
| | - Lisa M Giocomo
- Department of Neurobiology, Stanford University , Stanford, California
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38
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Ohara S, Onodera M, Simonsen ØW, Yoshino R, Hioki H, Iijima T, Tsutsui KI, Witter MP. Intrinsic Projections of Layer Vb Neurons to Layers Va, III, and II in the Lateral and Medial Entorhinal Cortex of the Rat. Cell Rep 2018; 24:107-116. [DOI: 10.1016/j.celrep.2018.06.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/04/2018] [Accepted: 06/01/2018] [Indexed: 12/29/2022] Open
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Cellular components and circuitry of the presubiculum and its functional role in the head direction system. Cell Tissue Res 2018; 373:541-556. [PMID: 29789927 DOI: 10.1007/s00441-018-2841-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 04/10/2018] [Indexed: 12/20/2022]
Abstract
Orientation in space is a fundamental cognitive process relying on brain-wide neuronal circuits. Many neurons in the presubiculum in the parahippocampal region encode head direction and each head direction cell selectively discharges when the animal faces a specific direction. Here, we attempt to link the current knowledge of afferent and efferent connectivity of the presubiculum to the processing of the head direction signal. We describe the cytoarchitecture of the presubicular six-layered cortex and the morphological and electrophysiological intrinsic properties of principal neurons and interneurons. While the presubicular head direction signal depends on synaptic input from thalamus, the intra- and interlaminar information flow in the microcircuit of the presubiculum may contribute to refine directional tuning. The interaction of a specific interneuron type, the Martinotti cells, with the excitatory pyramidal cells may maintain the head direction signal in the presubiculum with attractor-like properties.
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40
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Zutshi I, Brandon MP, Fu ML, Donegan ML, Leutgeb JK, Leutgeb S. Hippocampal Neural Circuits Respond to Optogenetic Pacing of Theta Frequencies by Generating Accelerated Oscillation Frequencies. Curr Biol 2018; 28:1179-1188.e3. [PMID: 29628373 DOI: 10.1016/j.cub.2018.02.061] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 01/23/2018] [Accepted: 02/22/2018] [Indexed: 01/25/2023]
Abstract
Biological oscillations can be controlled by a small population of rhythmic pacemaker cells, or in the brain, they also can emerge from complex cellular and circuit-level interactions. Whether and how these mechanisms are combined to give rise to oscillatory patterns that govern cognitive function are not well understood. For example, the activity of hippocampal networks is temporally coordinated by a 7- to 9-Hz local field potential (LFP) theta rhythm, yet many individual cells decouple from the LFP frequency to oscillate at frequencies ∼1 Hz higher. To better understand the network interactions that produce these complex oscillatory patterns, we asked whether the relative frequency difference between LFP and individual cells is retained when the LFP frequency is perturbed experimentally. We found that rhythmic optogenetic stimulation of medial septal GABAergic neurons controlled the hippocampal LFP frequency outside of the endogenous theta range, even during behavioral states when endogenous mechanisms would otherwise have generated 7- to 9-Hz theta oscillations. While the LFP frequency matched the optogenetically induced stimulation frequency, the oscillation frequency of individual hippocampal cells remained broadly distributed, and in a subset of cells including interneurons, it was accelerated beyond the new base LFP frequency. The inputs from septal GABAergic neurons to the hippocampus, therefore, do not appear to directly control the cellular oscillation frequency but rather engage cellular and circuit mechanisms that accelerate the rhythmicity of individual cells. Thus, theta oscillations are an example of cortical oscillations that combine inputs from a subcortical pacemaker with local computations to generate complex oscillatory patterns that support cognitive functions.
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Affiliation(s)
- Ipshita Zutshi
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Mark P Brandon
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA; Douglas Hospital Research Centre, Department of Psychiatry, McGill University, 6875 LaSalle Blvd., Montreal, QC H4H 1R3, Canada.
| | - Maylin L Fu
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Macayla L Donegan
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Jill K Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Stefan Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA; Kavli Institute for Brain and Mind, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA.
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41
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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] [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.
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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
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Ferrante M, Tahvildari B, Duque A, Hadzipasic M, Salkoff D, Zagha EW, Hasselmo ME, McCormick DA. Distinct Functional Groups Emerge from the Intrinsic Properties of Molecularly Identified Entorhinal Interneurons and Principal Cells. Cereb Cortex 2018; 27:3186-3207. [PMID: 27269961 DOI: 10.1093/cercor/bhw143] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Inhibitory interneurons are an important source of synaptic inputs that may contribute to network mechanisms for coding of spatial location by entorhinal cortex (EC). The intrinsic properties of inhibitory interneurons in the EC of the mouse are mostly undescribed. Intrinsic properties were recorded from known cell types, such as, stellate and pyramidal cells and 6 classes of molecularly identified interneurons (regulator of calcineurin 2, somatostatin, serotonin receptor 3a, neuropeptide Y neurogliaform (NGF), neuropeptide Y non-NGF, and vasoactive intestinal protein) in acute brain slices. We report a broad physiological diversity between and within cell classes. We also found differences in the ability to produce postinhibitory rebound spikes and in the frequency and amplitude of incoming EPSPs. To understand the source of this intrinsic variability we applied hierarchical cluster analysis to functionally classify neurons. These analyses revealed physiologically derived cell types in EC that mostly corresponded to the lines identified by biomarkers with a few unexpected and important differences. Finally, we reduced the complex multidimensional space of intrinsic properties to the most salient five that predicted the cellular biomolecular identity with 81.4% accuracy. These results provide a framework for the classification of functional subtypes of cortical neurons by their intrinsic membrane properties.
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Affiliation(s)
- Michele Ferrante
- Center for Memory and Brain.,Center for Systems Neuroscience.,Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
| | - Babak Tahvildari
- Department of Neurobiology.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06520-8001, USA
| | - Alvaro Duque
- Department of Neurobiology.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06520-8001, USA
| | - Muhamed Hadzipasic
- Interdepartmental Program in Neuroscience, Yale School of Medicine, New Haven, CT 06520-8001, USA
| | - David Salkoff
- Department of Neurobiology.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06520-8001, USA
| | - Edward William Zagha
- Department of Neurobiology.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06520-8001, USA
| | - Michael E Hasselmo
- Center for Memory and Brain.,Center for Systems Neuroscience.,Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
| | - David A McCormick
- Department of Neurobiology.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06520-8001, USA
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43
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Unal G, Crump MG, Viney TJ, Éltes T, Katona L, Klausberger T, Somogyi P. Spatio-temporal specialization of GABAergic septo-hippocampal neurons for rhythmic network activity. Brain Struct Funct 2018; 223:2409-2432. [PMID: 29500537 PMCID: PMC5968071 DOI: 10.1007/s00429-018-1626-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 02/10/2018] [Indexed: 01/06/2023]
Abstract
Medial septal GABAergic neurons of the basal forebrain innervate the hippocampus and related cortical areas, contributing to the coordination of network activity, such as theta oscillations and sharp wave-ripple events, via a preferential innervation of GABAergic interneurons. Individual medial septal neurons display diverse activity patterns, which may be related to their termination in different cortical areas and/or to the different types of innervated interneurons. To test these hypotheses, we extracellularly recorded and juxtacellularly labeled single medial septal neurons in anesthetized rats in vivo during hippocampal theta and ripple oscillations, traced their axons to distant cortical target areas, and analyzed their postsynaptic interneurons. Medial septal GABAergic neurons exhibiting different hippocampal theta phase preferences and/or sharp wave-ripple related activity terminated in restricted hippocampal regions, and selectively targeted a limited number of interneuron types, as established on the basis of molecular markers. We demonstrate the preferential innervation of bistratified cells in CA1 and of basket cells in CA3 by individual axons. One group of septal neurons was suppressed during sharp wave-ripples, maintained their firing rate across theta and non-theta network states and mainly fired along the descending phase of CA1 theta oscillations. In contrast, neurons that were active during sharp wave-ripples increased their firing significantly during "theta" compared to "non-theta" states, with most firing during the ascending phase of theta oscillations. These results demonstrate that specialized septal GABAergic neurons contribute to the coordination of network activity through parallel, target area- and cell type-selective projections to the hippocampus.
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Affiliation(s)
- Gunes Unal
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK.
- Department of Psychology, Bogazici University, 34342, Istanbul, Turkey.
| | - Michael G Crump
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Tim J Viney
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Tímea Éltes
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, Hungary
| | - Linda Katona
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK
| | - Thomas Klausberger
- Center for Brain Research, Medical University of Vienna, 1090, Vienna, Austria
| | - Peter Somogyi
- Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, OX1 3QT, UK.
- Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, Hungary.
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44
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Target selectivity of septal cholinergic neurons in the medial and lateral entorhinal cortex. Proc Natl Acad Sci U S A 2018; 115:E2644-E2652. [PMID: 29487212 PMCID: PMC5856533 DOI: 10.1073/pnas.1716531115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [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.
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45
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Zhang GW, Sun WJ, Zingg B, Shen L, He J, Xiong Y, Tao HW, Zhang LI. A Non-canonical Reticular-Limbic Central Auditory Pathway via Medial Septum Contributes to Fear Conditioning. Neuron 2018; 97:406-417.e4. [PMID: 29290554 PMCID: PMC5798467 DOI: 10.1016/j.neuron.2017.12.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/06/2017] [Accepted: 12/05/2017] [Indexed: 11/26/2022]
Abstract
In the mammalian brain, auditory information is known to be processed along a central ascending pathway leading to auditory cortex (AC). Whether there exist any major pathways beyond this canonical auditory neuraxis remains unclear. In awake mice, we found that auditory responses in entorhinal cortex (EC) cannot be explained by a previously proposed relay from AC based on response properties. By combining anatomical tracing and optogenetic/pharmacological manipulations, we discovered that EC received auditory input primarily from the medial septum (MS), rather than AC. A previously uncharacterized auditory pathway was then revealed: it branched from the cochlear nucleus, and via caudal pontine reticular nucleus, pontine central gray, and MS, reached EC. Neurons along this non-canonical auditory pathway responded selectively to high-intensity broadband noise, but not pure tones. Disruption of the pathway resulted in an impairment of specifically noise-cued fear conditioning. This reticular-limbic pathway may thus function in processing aversive acoustic signals.
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Affiliation(s)
- Guang-Wei Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, 30 Gaotanyan St., Chongqing, 400038, China; Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Wen-Jian Sun
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong
| | - Brian Zingg
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA; Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Li Shen
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Jufang He
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong
| | - Ying Xiong
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, 30 Gaotanyan St., Chongqing, 400038, China.
| | - Huizhong W Tao
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
| | - Li I Zhang
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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46
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Schmidt-Hieber C, Nolan MF. Synaptic integrative mechanisms for spatial cognition. Nat Neurosci 2017; 20:1483-1492. [PMID: 29073648 DOI: 10.1038/nn.4652] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/22/2017] [Indexed: 12/11/2022]
Abstract
Synaptic integrative mechanisms have profound effects on electrical signaling in the brain that, although largely hidden from recording methods that observe the spiking activity of neurons, may be critical for the encoding, storage and retrieval of information. Here we review roles for synaptic integrative mechanisms in the selection, generation and plasticity of place and grid fields, and in related temporal codes for the representation of space. We outline outstanding questions and challenges in the testing of hypothesized models for spatial computation and memory.
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Affiliation(s)
| | - Matthew F Nolan
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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47
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Anatomical and Electrophysiological Clustering of Superficial Medial Entorhinal Cortex Interneurons. eNeuro 2017; 4:eN-NWR-0263-16. [PMID: 29085901 PMCID: PMC5659260 DOI: 10.1523/eneuro.0263-16.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/19/2017] [Accepted: 09/29/2017] [Indexed: 01/03/2023] Open
Abstract
Local GABAergic interneurons regulate the activity of spatially-modulated principal cells in the medial entorhinal cortex (MEC), mediating stellate-to-stellate connectivity and possibly enabling grid formation via recurrent inhibitory circuitry. Despite the important role interneurons seem to play in the MEC cortical circuit, the combination of low cell counts and functional diversity has made systematic electrophysiological studies of these neurons difficult. For these reasons, there remains a paucity of knowledge on the electrophysiological profiles of superficial MEC interneuron populations. Taking advantage of glutamic acid decarboxylase 2 (GAD2)-IRES-tdTomato and PV-tdTomato transgenic mice, we targeted GABAergic interneurons for whole-cell patch-clamp recordings and characterized their passive membrane features, basic input/output properties and action potential (AP) shape. These electrophysiologically characterized cells were then anatomically reconstructed, with emphasis on axonal projections and pial depth. K-means clustering of interneuron anatomical and electrophysiological data optimally classified a population of 106 interneurons into four distinct clusters. The first cluster is comprised of layer 2- and 3-projecting, slow-firing interneurons. The second cluster is comprised largely of PV+ fast-firing interneurons that project mainly to layers 2 and 3. The third cluster contains layer 1- and 2-projecting interneurons, and the fourth cluster is made up of layer 1-projecting horizontal interneurons. These results, among others, will provide greater understanding of the electrophysiological characteristics of MEC interneurons, help guide future in vivo studies, and may aid in uncovering the mechanism of grid field formation.
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48
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Identified GABAergic and Glutamatergic Neurons in the Mouse Inferior Colliculus Share Similar Response Properties. J Neurosci 2017; 37:8952-8964. [PMID: 28842411 DOI: 10.1523/jneurosci.0745-17.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/19/2017] [Accepted: 08/05/2017] [Indexed: 12/13/2022] Open
Abstract
GABAergic neurons in the inferior colliculus (IC) play a critical role in auditory information processing, yet their responses to sound are unknown. Here, we used optogenetic methods to characterize the response properties of GABAergic and presumed glutamatergic neurons to sound in the IC. We found that responses to pure tones of both inhibitory and excitatory classes of neurons were similar in their thresholds, response latencies, rate-level functions, and frequency tuning, but GABAergic neurons may have higher spontaneous firing rates. In contrast to their responses to pure tones, the inhibitory and excitatory neurons differed in their ability to follow amplitude modulations. The responses of both cell classes were affected by their location regardless of the cell type, especially in terms of their frequency tuning. These results show that the synaptic domain, a unique organization of local neural circuits in the IC, may interact with all types of neurons to produce their ultimate response to sound.SIGNIFICANCE STATEMENT Although the inferior colliculus (IC) in the auditory midbrain is composed of different types of neurons, little is known about how these specific types of neurons respond to sound. Here, for the first time, we characterized the response properties of GABAergic and glutamatergic neurons in the IC. Both classes of neurons had diverse response properties to tones but were overall similar, except for the spontaneous activity and their ability to follow amplitude-modulated sound. Both classes of neurons may compose a basic local circuit that is replicated throughout the IC. Within each local circuit, the inputs to the local circuit may have a greater influence in determining the response properties to sound than the specific neuron types.
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49
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Affiliation(s)
| | - Matthew F Nolan
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, UK
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50
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Justus D, Dalügge D, Bothe S, Fuhrmann F, Hannes C, Kaneko H, Friedrichs D, Sosulina L, Schwarz I, Elliott DA, Schoch S, Bradke F, Schwarz MK, Remy S. Glutamatergic synaptic integration of locomotion speed via septoentorhinal projections. Nat Neurosci 2016; 20:16-19. [PMID: 27893726 DOI: 10.1038/nn.4447] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/01/2016] [Indexed: 12/21/2022]
Abstract
The medial septum and diagonal band of Broca (MSDB) send glutamatergic axons to medial entorhinal cortex (MEC). We found that this pathway provides speed-correlated input to several MEC cell-types in layer 2/3. The speed signal is integrated most effectively by pyramidal cells but also excites stellate cells and interneurons. Thus, the MSDB conveys speed information that can be used by MEC neurons for spatial representation of self-location.
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Affiliation(s)
- Daniel Justus
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Dennis Dalügge
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Stefanie Bothe
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Falko Fuhrmann
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Christian Hannes
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Hiroshi Kaneko
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Detlef Friedrichs
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Liudmila Sosulina
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Inna Schwarz
- Functional Neuroconnectomics Group, Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - David Anthony Elliott
- Axon Growth and Regeneration Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Susanne Schoch
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany.,Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Frank Bradke
- Axon Growth and Regeneration Group, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Martin Karl Schwarz
- Functional Neuroconnectomics Group, Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Stefan Remy
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany.,Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
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