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Rolls ET, Treves A. A theory of hippocampal function: New developments. Prog Neurobiol 2024; 238:102636. [PMID: 38834132 DOI: 10.1016/j.pneurobio.2024.102636] [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: 01/27/2024] [Revised: 04/15/2024] [Accepted: 05/30/2024] [Indexed: 06/06/2024]
Abstract
We develop further here the only quantitative theory of the storage of information in the hippocampal episodic memory system and its recall back to the neocortex. The theory is upgraded to account for a revolution in understanding of spatial representations in the primate, including human, hippocampus, that go beyond the place where the individual is located, to the location being viewed in a scene. This is fundamental to much primate episodic memory and navigation: functions supported in humans by pathways that build 'where' spatial view representations by feature combinations in a ventromedial visual cortical stream, separate from those for 'what' object and face information to the inferior temporal visual cortex, and for reward information from the orbitofrontal cortex. Key new computational developments include the capacity of the CA3 attractor network for storing whole charts of space; how the correlations inherent in self-organizing continuous spatial representations impact the storage capacity; how the CA3 network can combine continuous spatial and discrete object and reward representations; the roles of the rewards that reach the hippocampus in the later consolidation into long-term memory in part via cholinergic pathways from the orbitofrontal cortex; and new ways of analysing neocortical information storage using Potts networks.
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Affiliation(s)
- Edmund T Rolls
- Oxford Centre for Computational Neuroscience, Oxford, UK; Department of Computer Science, University of Warwick, Coventry CV4 7AL, UK.
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2
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Bruentgens F, Moreno Velasquez L, Stumpf A, Parthier D, Breustedt J, Benfenati F, Milovanovic D, Schmitz D, Orlando M. The Lack of Synapsin Alters Presynaptic Plasticity at Hippocampal Mossy Fibers in Male Mice. eNeuro 2024; 11:ENEURO.0330-23.2024. [PMID: 38866497 PMCID: PMC11223178 DOI: 10.1523/eneuro.0330-23.2024] [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: 08/29/2023] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/14/2024] Open
Abstract
Synapsins are highly abundant presynaptic proteins that play a crucial role in neurotransmission and plasticity via the clustering of synaptic vesicles. The synapsin III isoform is usually downregulated after development, but in hippocampal mossy fiber boutons, it persists in adulthood. Mossy fiber boutons express presynaptic forms of short- and long-term plasticity, which are thought to underlie different forms of learning. Previous research on synapsins at this synapse focused on synapsin isoforms I and II. Thus, a complete picture regarding the role of synapsins in mossy fiber plasticity is still missing. Here, we investigated presynaptic plasticity at hippocampal mossy fiber boutons by combining electrophysiological field recordings and transmission electron microscopy in a mouse model lacking all synapsin isoforms. We found decreased short-term plasticity, i.e., decreased facilitation and post-tetanic potentiation, but increased long-term potentiation in male synapsin triple knock-out (KO) mice. At the ultrastructural level, we observed more dispersed vesicles and a higher density of active zones in mossy fiber boutons from KO animals. Our results indicate that all synapsin isoforms are required for fine regulation of short- and long-term presynaptic plasticity at the mossy fiber synapse.
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Affiliation(s)
- Felicitas Bruentgens
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Laura Moreno Velasquez
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Alexander Stumpf
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Daniel Parthier
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Jörg Breustedt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa 16163, Italy
- IRCCS Ospedale Policlinico San Martino, Genoa 16132, Italy
| | - Dragomir Milovanovic
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin 10117, Germany
- Einstein Center for Neurosciences, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Berlin, Berlin 10117, Germany
| | - Dietmar Schmitz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin 10117, Germany
- Einstein Center for Neurosciences, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Berlin, Berlin 10117, Germany
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin 10115, Germany
| | - Marta Orlando
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
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3
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Vandael D, Jonas P. Structure, biophysics, and circuit function of a "giant" cortical presynaptic terminal. Science 2024; 383:eadg6757. [PMID: 38452088 DOI: 10.1126/science.adg6757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/19/2024] [Indexed: 03/09/2024]
Abstract
The hippocampal mossy fiber synapse, formed between axons of dentate gyrus granule cells and dendrites of CA3 pyramidal neurons, is a key synapse in the trisynaptic circuitry of the hippocampus. Because of its comparatively large size, this synapse is accessible to direct presynaptic recording, allowing a rigorous investigation of the biophysical mechanisms of synaptic transmission and plasticity. Furthermore, because of its placement in the very center of the hippocampal memory circuit, this synapse seems to be critically involved in several higher network functions, such as learning, memory, pattern separation, and pattern completion. Recent work based on new technologies in both nanoanatomy and nanophysiology, including presynaptic patch-clamp recording, paired recording, super-resolution light microscopy, and freeze-fracture and "flash-and-freeze" electron microscopy, has provided new insights into the structure, biophysics, and network function of this intriguing synapse. This brings us one step closer to answering a fundamental question in neuroscience: how basic synaptic properties shape higher network computations.
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Affiliation(s)
- David Vandael
- Institute of Science and Technology Austria (ISTA), A-3400 Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), A-3400 Klosterneuburg, Austria
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Borzello M, Ramirez S, Treves A, Lee I, Scharfman H, Stark C, Knierim JJ, Rangel LM. Assessments of dentate gyrus function: discoveries and debates. Nat Rev Neurosci 2023; 24:502-517. [PMID: 37316588 PMCID: PMC10529488 DOI: 10.1038/s41583-023-00710-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/16/2023]
Abstract
There has been considerable speculation regarding the function of the dentate gyrus (DG) - a subregion of the mammalian hippocampus - in learning and memory. In this Perspective article, we compare leading theories of DG function. We note that these theories all critically rely on the generation of distinct patterns of activity in the region to signal differences between experiences and to reduce interference between memories. However, these theories are divided by the roles they attribute to the DG during learning and recall and by the contributions they ascribe to specific inputs or cell types within the DG. These differences influence the information that the DG is thought to impart to downstream structures. We work towards a holistic view of the role of DG in learning and memory by first developing three critical questions to foster a dialogue between the leading theories. We then evaluate the extent to which previous studies address our questions, highlight remaining areas of conflict, and suggest future experiments to bridge these theories.
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Affiliation(s)
- Mia Borzello
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA
| | - Steve Ramirez
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | | | - Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| | - Helen Scharfman
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology and Psychiatry and the Neuroscience Institute, New York University Langone Health, New York, NY, USA
- The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Craig Stark
- Department of Neurobiology and Behaviour, University of California, Irvine, Irvine, CA, USA
| | - James J Knierim
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Lara M Rangel
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA.
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Amer T, Davachi L. Extra-hippocampal contributions to pattern separation. eLife 2023; 12:82250. [PMID: 36972123 PMCID: PMC10042541 DOI: 10.7554/elife.82250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Pattern separation, or the process by which highly similar stimuli or experiences in memory are represented by non-overlapping neural ensembles, has typically been ascribed to processes supported by the hippocampus. Converging evidence from a wide range of studies, however, suggests that pattern separation is a multistage process supported by a network of brain regions. Based on this evidence, considered together with related findings from the interference resolution literature, we propose the 'cortico-hippocampal pattern separation' (CHiPS) framework, which asserts that brain regions involved in cognitive control play a significant role in pattern separation. Particularly, these regions may contribute to pattern separation by (1) resolving interference in sensory regions that project to the hippocampus, thus regulating its cortical input, or (2) directly modulating hippocampal processes in accordance with task demands. Considering recent interest in how hippocampal operations are modulated by goal states likely represented and regulated by extra-hippocampal regions, we argue that pattern separation is similarly supported by neocortical-hippocampal interactions.
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Affiliation(s)
- Tarek Amer
- Department of Psychology, University of Victoria, Victoria, Canada
| | - Lila Davachi
- Department of Psychology, Columbia University, New York, United States
- Nathan Kline Research Institute, Orangeburg, United States
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Chrusch MJ, Fu S, Spanswick SC, Vecchiarelli HA, Patel PP, Hill MN, Dyck RH. Environmental Enrichment Engages Vesicular Zinc Signaling to Enhance Hippocampal Neurogenesis. Cells 2023; 12:cells12060883. [PMID: 36980224 PMCID: PMC10046929 DOI: 10.3390/cells12060883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/09/2023] [Accepted: 03/11/2023] [Indexed: 03/14/2023] Open
Abstract
Zinc is highly concentrated in synaptic vesicles throughout the mammalian telencephalon and, in particular, the hippocampal dentate gyrus. A role for zinc in modulating synaptic plasticity has been inferred, but whether zinc has a particular role in experience-dependent plasticity has yet to be determined. The aim of the current study was to determine whether vesicular zinc is important for modulating adult hippocampal neurogenesis in an experience-dependent manner and, consequently, hippocampal-dependent behaviour. We assessed the role of vesicular zinc in modulating hippocampal neurogenesis and behaviour by comparing ZnT3 knockout (KO) mice, which lack vesicular zinc, to wild-type (WT) littermates exposed to either standard housing conditions (SH) or an enriched environment (EE). We found that vesicular zinc is necessary for a cascade of changes in hippocampal plasticity following EE, such as increases in hippocampal neurogenesis and elevations in mature brain-derived neurotrophic factor (mBDNF), but was otherwise dispensable under SH conditions. Using the Spatial Object Recognition task and the Morris Water task we show that, unlike WT mice, ZnT3 KO mice showed no improvements in spatial memory following EE. These experiments demonstrate that vesicular zinc is essential for the enhancement of adult hippocampal neurogenesis and behaviour following enrichment, supporting a role for zincergic neurons in contributing to experience-dependent plasticity in the hippocampus.
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Affiliation(s)
- Michael J. Chrusch
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.J.C.); (S.F.); (S.C.S.); (H.A.V.); (M.N.H.)
- Department of Neuroscience, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Selena Fu
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.J.C.); (S.F.); (S.C.S.); (H.A.V.); (M.N.H.)
- Department of Psychology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Simon C. Spanswick
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.J.C.); (S.F.); (S.C.S.); (H.A.V.); (M.N.H.)
- Department of Psychology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Haley A. Vecchiarelli
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.J.C.); (S.F.); (S.C.S.); (H.A.V.); (M.N.H.)
- Department of Neuroscience, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Payal P. Patel
- Department of Psychology, University of Calgary, Calgary, AB T2N 1N4, Canada
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Matthew N. Hill
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.J.C.); (S.F.); (S.C.S.); (H.A.V.); (M.N.H.)
- Department of Neuroscience, University of Calgary, Calgary, AB T2N 1N4, Canada
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Richard H. Dyck
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.J.C.); (S.F.); (S.C.S.); (H.A.V.); (M.N.H.)
- Department of Psychology, University of Calgary, Calgary, AB T2N 1N4, Canada
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB T2N 1N4, Canada
- Correspondence:
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Devine MJ, Szulc BR, Howden JH, López-Doménech G, Ruiz A, Kittler JT. Mitochondrial Ca2+ uniporter haploinsufficiency enhances long-term potentiation at hippocampal mossy fibre synapses. J Cell Sci 2022; 135:jcs259823. [PMID: 36274588 PMCID: PMC10563808 DOI: 10.1242/jcs.259823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 10/18/2022] [Indexed: 11/20/2022] Open
Abstract
Long-term changes in synaptic strength form the basis of learning and memory. These changes rely upon energy-demanding mechanisms, which are regulated by local Ca2+ signalling. Mitochondria are optimised for providing energy and buffering Ca2+. However, our understanding of the role of mitochondria in regulating synaptic plasticity is incomplete. Here, we have used optical and electrophysiological techniques in cultured hippocampal neurons and ex vivo hippocampal slices from mice with haploinsufficiency of the mitochondrial Ca2+ uniporter (MCU+/-) to address whether reducing mitochondrial Ca2+ uptake alters synaptic transmission and plasticity. We found that cultured MCU+/- hippocampal neurons have impaired Ca2+ clearance, and consequently enhanced synaptic vesicle fusion at presynapses occupied by mitochondria. Furthermore, long-term potentiation (LTP) at mossy fibre (MF) synapses, a process which is dependent on presynaptic Ca2+ accumulation, is enhanced in MCU+/- slices. Our results reveal a previously unrecognised role for mitochondria in regulating presynaptic plasticity of a major excitatory pathway involved in learning and memory.
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Affiliation(s)
- Michael J. Devine
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Blanka R. Szulc
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Jack H. Howden
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Guillermo López-Doménech
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Arnaud Ruiz
- Department of Pharmacology, School of Pharmacy, University College London, Brunswick Square, London WC1N 1AX, UK
| | - Josef T. Kittler
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
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Sikora J, Di Bisceglie Caballero S, Reiss D, Kieffer BL, Paoletti P, Jacob PY, Ouagazzal AM. Zn2+ inhibits spatial memory and hippocampal place cell representation through high-affinity binding to the NMDA receptor GluN2A subunit. iScience 2022; 25:105355. [DOI: 10.1016/j.isci.2022.105355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/11/2022] [Accepted: 10/11/2022] [Indexed: 10/31/2022] Open
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Soldatkina O, Schönsberg F, Treves A. Challenges for Place and Grid Cell Models. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1359:285-312. [DOI: 10.1007/978-3-030-89439-9_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Fiedler J, De Leonibus E, Treves A. Has the hippocampus really forgotten about space? Curr Opin Neurobiol 2021; 71:164-169. [PMID: 34847486 DOI: 10.1016/j.conb.2021.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/30/2021] [Accepted: 11/10/2021] [Indexed: 11/28/2022]
Abstract
Several lines of evidence, including the discovery of place cells, have contributed to the notion that the hippocampus serves primarily to navigate the environment, as a repository of spatial memories, like a drawer full of charts; and that in some species it has exapted on this original one an episodic memory function. We argue that recent evidence questions the primacy of space, and points at memory load, whether spatial or not, as the challenge that mammalian hippocampal circuitry has evolved to meet.
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Affiliation(s)
| | | | - Alessandro Treves
- SISSA - Cognitive Neuroscience, Trieste, Italy; Kavli Centre for Neural Computation, NTNU, Trondheim, Norway.
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11
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Badner A, Reinhardt EK, Nguyen TV, Midani N, Marshall AT, Lepe CA, Echeverria K, Lepe JJ, Torrecampo V, Bertan SH, Tran SH, Anderson AJ, Cummings BJ. Freshly Thawed Cryobanked Human Neural Stem Cells Engraft within Endogenous Neurogenic Niches and Restore Cognitive Function after Chronic Traumatic Brain Injury. J Neurotrauma 2021; 38:2731-2746. [PMID: 34130484 DOI: 10.1089/neu.2021.0045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Human neural stem cells (hNSCs) have potential as a cell therapy after traumatic brain injury (TBI). While various studies have demonstrated the efficacy of NSCs from ongoing culture, there is a significant gap in our understanding of freshly thawed cells from cryobanked stocks-a more clinically relevant source. To address these shortfalls, the therapeutic potential of our previously validated Shef-6.0 human embryonic stem cell (hESC)-derived hNSC line was tested after long-term cryostorage and thawing before transplant. Immunodeficient athymic nude rats received a moderate unilateral controlled cortical impact (CCI) injury. At four weeks post-injury, 6 × 105 freshly thawed hNSCs were transplanted into six injection sites (two ipsi- and four contra-lateral) with 53.4% of cells surviving three months post-transplant. Interestingly, most hNSCs were engrafted in the meninges and the lining of lateral ventricles, associated with high CXCR4 expression and a chemotactic response to SDF1alpha (CXCL12). While some expressed markers of neuron, astrocyte, and oligodendrocyte lineages, the majority remained progenitors, identified through doublecortin expression (78.1%). Importantly, transplantation resulted in improved spatial learning and memory in Morris water maze navigation and reduced risk taking in an elevated plus maze. Investigating potential mechanisms of action, we identified an increase in ipsilateral host hippocampus cornu ammonis (CA) neuron survival, contralateral dentate gyrus (DG) volume, and DG neural progenitor morphology as well as a reduction in neuroinflammation. Together, these findings validate the potential of hNSCs to improve function after TBI and demonstrate that long-term biobanking of cells and thawing aliquots before use may be suitable for clinical deployment.
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Affiliation(s)
- Anna Badner
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Emily K Reinhardt
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, California, USA
| | - Theodore V Nguyen
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Nicole Midani
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Andrew T Marshall
- Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Cherie A Lepe
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Karla Echeverria
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Javier J Lepe
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Vincent Torrecampo
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
| | - Sara H Bertan
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, California, USA
| | - Serinee H Tran
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, California, USA
| | - Aileen J Anderson
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, California, USA
- Physical Medicine and Rehabilitation, University of California, Irvine, Irvine, California, USA
- Anatomy and Neurobiology, University of California, Irvine, Irvine, California, USA
| | - Brian J Cummings
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, California, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, California, USA
- Physical Medicine and Rehabilitation, University of California, Irvine, Irvine, California, USA
- Anatomy and Neurobiology, University of California, Irvine, Irvine, California, USA
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12
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Glasgow SD, Wong EW, Thompson-Steckel G, Marcal N, Séguéla P, Ruthazer ES, Kennedy TE. Pre- and post-synaptic roles for DCC in memory consolidation in the adult mouse hippocampus. Mol Brain 2020; 13:56. [PMID: 32264905 PMCID: PMC7137442 DOI: 10.1186/s13041-020-00597-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/26/2020] [Indexed: 11/10/2022] Open
Abstract
The receptor deleted in colorectal cancer (DCC) and its ligand netrin-1 are essential for axon guidance during development and are expressed by neurons in the mature brain. Netrin-1 recruits GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and is critical for long-term potentiation (LTP) at CA3-CA1 hippocampal Schaffer collateral synapses, while conditional DCC deletion from glutamatergic neurons impairs hippocampal-dependent spatial memory and severely disrupts LTP induction. DCC co-fractionates with the detergent-resistant component of postsynaptic density, yet is enriched in axonal growth cones that differentiate into presynaptic terminals during development. Specific presynaptic and postsynaptic contributions of DCC to the function of mature neural circuits have yet to be identified. Employing hippocampal subregion-specific conditional deletion of DCC, we show that DCC loss from CA1 hippocampal pyramidal neurons resulted in deficits in spatial memory, increased resting membrane potential, abnormal dendritic spine morphology, weaker spontaneous excitatory postsynaptic activity, and reduced levels of postsynaptic adaptor and signaling proteins; however, the capacity to induce LTP remained intact. In contrast, deletion of DCC from CA3 neurons did not induce detectable changes in the intrinsic electrophysiological properties of CA1 pyramidal neurons, but impaired performance on the novel object place recognition task as well as compromised excitatory synaptic transmission and LTP at Schaffer collateral synapses. Together, these findings reveal specific pre- and post-synaptic contributions of DCC to hippocampal synaptic plasticity underlying spatial memory.
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Affiliation(s)
- Stephen D Glasgow
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada.,NSERC CREATE Neuroengineering Training Program, McGill University, Montréal, Canada
| | - Edwin W Wong
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada
| | - Greta Thompson-Steckel
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada
| | - Nathalie Marcal
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada
| | - Philippe Séguéla
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada
| | - Edward S Ruthazer
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada
| | - Timothy E Kennedy
- Montréal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montréal, Québec, H3A 2B4, Canada. .,NSERC CREATE Neuroengineering Training Program, McGill University, Montréal, Canada. .,Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, Quebec, H3A 0C7, Canada.
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13
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Dentate gyrus circuits for encoding, retrieval and discrimination of episodic memories. Nat Rev Neurosci 2020; 21:153-168. [PMID: 32042144 DOI: 10.1038/s41583-019-0260-z] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2019] [Indexed: 12/19/2022]
Abstract
The dentate gyrus (DG) has a key role in hippocampal memory formation. Intriguingly, DG lesions impair many, but not all, hippocampus-dependent mnemonic functions, indicating that the rest of the hippocampus (CA1-CA3) can operate autonomously under certain conditions. An extensive body of theoretical work has proposed how the architectural elements and various cell types of the DG may underlie its function in cognition. Recent studies recorded and manipulated the activity of different neuron types in the DG during memory tasks and have provided exciting new insights into the mechanisms of DG computational processes, particularly for the encoding, retrieval and discrimination of similar memories. Here, we review these DG-dependent mnemonic functions in light of the new findings and explore mechanistic links between the cellular and network properties of, and the computations performed by, the DG.
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14
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Sikora J, Kieffer BL, Paoletti P, Ouagazzal AM. Synaptic zinc contributes to motor and cognitive deficits in 6-hydroxydopamine mouse models of Parkinson's disease. Neurobiol Dis 2019; 134:104681. [PMID: 31759136 DOI: 10.1016/j.nbd.2019.104681] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/05/2019] [Accepted: 11/19/2019] [Indexed: 12/19/2022] Open
Abstract
Hyperactivity of glutamatergic corticostrial pathways is recognized as a key pathophysiological mechanism contributing to development of PD symptoms and dopaminergic neurotoxicity. Subset of corticostriatal projection neurons uses Zn2+ as a co-transmitter alongside glutamate, but the role of synaptically released Zn2+ in PD remains unexplored. We used genetically modified mice and pharmacological tools in combination with 6-hydroxydopamine (6-OHDA) lesion models of PD to investigate the contribution of synaptic zinc to disease associated behavioral deficits and neurodegeneration. Vesicular zinc transporter-3 (ZnT3) knockout mice lacking releasable Zn2+ were more resistant to locomotor deficit and memory impairment of nigrostriatal dopamine (DA) denervation compared to wildtype littermates. The loss of striatal dopaminergic fibers was comparable between genotypes, indicating that synaptically released Zn2+ contributes to behavioral deficits but not neurotoxic effects of 6-OHDA. To gain further insight into the mechanisms of Zn2+ actions, we used the extracellular Zn2+ chelator CaEDTA and knock-in mice lacking the high affinity Zn2+ inhibition of GluN2A-containing NMDA receptors (GluN2A-NMDARs). Acute chelation of extracellular Zn2+ in the striatum restored locomotor deficit of 6-OHDA lesion, confirming that synaptic Zn2+ suppresses locomotor behavior. Disruption of the Zn2+-GluN2A interaction had, on the other hand, no impact on locomotor deficit or neurotoxic effect of 6-OHDA. Collectively, these findings provide clear evidence for the implication of striatal synaptic Zn2+ in the pathophysiology of PD. They unveil that synaptic Zn2+ plays predominantly a detrimental role by promoting motor and cognitive deficits caused by nigrostriatal DA denervation, pointing towards new therapeutic interventions.
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Affiliation(s)
- Joanna Sikora
- Laboratoire de Neurosciences Cognitives, Aix-Marseille Univ, CNRS, LNC, UMR 7291, 13331 Marseille, France; Aix-marseille Université, Marseille, France
| | - Brigitte L Kieffer
- Douglas Research Center, Department of Psychiatry, McGill University, Montréal, Canada
| | - Pierre Paoletti
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Université PSL, CNRS, INSERM, Paris, France
| | - Abdel-Mouttalib Ouagazzal
- Laboratoire de Neurosciences Cognitives, Aix-Marseille Univ, CNRS, LNC, UMR 7291, 13331 Marseille, France.
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15
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Hillerer KM, Slattery DA, Pletzer B. Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus. Front Neuroendocrinol 2019; 55:100796. [PMID: 31580837 PMCID: PMC7115954 DOI: 10.1016/j.yfrne.2019.100796] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/19/2022]
Abstract
Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.
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Affiliation(s)
- Katharina M Hillerer
- Department of Obstetrics and Gynaecology, Salzburger Landeskrankenhaus (SALK), Paracelsus Medical University (PMU), Clinical Research Center Salzburg (CRCS), Salzburg, Austria.
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Belinda Pletzer
- Department of Psychology, University of Salzburg, Salzburg, Austria; Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
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16
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Shi YW, Fan BF, Xue L, Wang XG, Ou XL. Fear renewal activates cyclic adenosine monophosphate signaling in the dentate gyrus. Brain Behav 2019; 9:e01280. [PMID: 31313894 PMCID: PMC6710207 DOI: 10.1002/brb3.1280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 03/13/2019] [Accepted: 03/14/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Fear renewal, the context-specific relapse of a conditioned fear after extinction, is a widely pursued model of post-traumatic stress disorder and phobias. However, its cellular and molecular mechanisms remain poorly understood. The dentate gyrus (DG) has emerged as a critical locus of plasticity with relevance to memory, anxiety disorders, and depression, and it contributes to fear memory retrieval. Here, we have identified the role of the DG in fear renewal and its molecular mechanism. MATERIALS AND METHODS Muscimol (MUS), activator of cyclic adenosine monophosphate (cAMP) forskolin (FSK), inhibitor of protein kinase A (PKA), Rip-cAMP, and a phosphodiesterase inhibitor rolipram were infused into DG of standard deviation rats before renewal testing. cAMP levels after fear renewal was measured by enzyme-linked immunosorbent assay. The protein levels of phosphodiesterase 4 (PDE4) isoforms were tested by western blot. At last, the roles of cAMP signaling were also tested in the acquisition of fear conditioning, fear retrieval, and extinction. RESULTS Intra-DG treatment of MUS and Rp-cAMP impaired fear renewal. FSK and rolipram exhibited the opposite effect, which also occurred in the retrieval of original fear memory. This change in fear renewal was regulated by PDE4 isoforms PDE4A, PDE4A5, and PDE4D. In addition, FSK and rolipram facilitated the acquisition of fear conditioning in long-term memory, but not short-term memory, while Rp-cAMP impaired long-term memory. For extinction, FSK and rolipram inhibited extinction process, while Rp-cAMP facilitated fear extinction. CONCLUSION These findings demonstrated that fear renewal activated cAMP signaling in the DG through decreased PDE4 activity. Because of the role of cAMP signaling in the acquisition or retrieval of fear conditioning and encoding of extinction, it is speculated that initial learning and extinction may have similarities in molecular mechanism, especially fear retrieval and fear renewal may share cAMP signaling pathway in the DG.
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Affiliation(s)
- Yan-Wei Shi
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Bu-Fang Fan
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Li Xue
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xiao-Guang Wang
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xue-Ling Ou
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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17
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Distinct hippocampal engrams control extinction and relapse of fear memory. Nat Neurosci 2019; 22:753-761. [PMID: 30936555 PMCID: PMC6705137 DOI: 10.1038/s41593-019-0361-z] [Citation(s) in RCA: 159] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 02/13/2019] [Indexed: 01/15/2023]
Abstract
Learned fear often relapses after extinction, suggesting that extinction training generates a new memory that coexists with the original fear memory; however, the mechanisms governing expression of competing fear and extinction memories remain unclear. We used activity-dependent neural tagging to investigate representations of fear and extinction memories in the dentate gyrus (DG). We demonstrate that extinction training suppresses reactivation of context fear engram cells, while activating a second ensemble, a putative extinction engram. Optogenetic inhibition of neurons that were active during extinction training increased fear after extinction training, whereas silencing neurons that were active during fear training reduced spontaneous recovery of fear. Optogenetic stimulation of fear acquisition neurons increased fear, while stimulation of extinction neurons suppressed fear and prevented spontaneous recovery. Our results indicate the hippocampus generates a fear extinction representation and that interactions between hippocampal fear and extinction representations govern suppression and relapse of fear after extinction.
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18
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Reshetnikov VV, Kovner AV, Lepeshko AA, Pavlov KS, Grinkevich LN, Bondar NP. Stress early in life leads to cognitive impairments, reduced numbers of CA3 neurons and altered maternal behavior in adult female mice. GENES BRAIN AND BEHAVIOR 2018; 19:e12541. [DOI: 10.1111/gbb.12541] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 02/02/2023]
Affiliation(s)
- Vasiliy V. Reshetnikov
- Laboratory of Gene Expression RegulationInstitute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences (SB RAS) Novosibirsk Russia
| | - Anna V. Kovner
- Laboratory of Molecular Mechanisms of Pathological ProcessesInstitute of Cytology and Genetics, SB RAS Novosibirsk Russia
| | - Arina A. Lepeshko
- Laboratory of Gene Expression RegulationInstitute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences (SB RAS) Novosibirsk Russia
- Novosibirsk National Research State University Novosibirsk Russia
| | - Konstantin S. Pavlov
- Laboratory of Experimental Models of Emotional PathologiesInstitute of Physiology and Basic Medicine Novosibirsk Russia
| | - Larisa N. Grinkevich
- Laboratory of Regulation of Functions of Brain NeuronsPavlov Institute of Physiology, RAS St. Petersburg Russia
| | - Natalya P. Bondar
- Laboratory of Gene Expression RegulationInstitute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences (SB RAS) Novosibirsk Russia
- Novosibirsk National Research State University Novosibirsk Russia
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19
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Llorens-Martín M. Exercising New Neurons to Vanquish Alzheimer Disease. Brain Plast 2018; 4:111-126. [PMID: 30564550 PMCID: PMC6296267 DOI: 10.3233/bpl-180065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Alzheimer disease (AD) is the most common type of dementia in individuals over 65 years of age. The neuropathological hallmarks of the condition are Tau neurofibrillary tangles and Amyloid-β senile plaques. Moreover, certain susceptible regions of the brain experience a generalized lack of neural plasticity and marked synaptic alterations during the progression of this as yet incurable disease. One of these regions, the hippocampus, is characterized by the continuous addition of new neurons throughout life. This phenomenon, named adult hippocampal neurogenesis (AHN), provides a potentially endless source of new synaptic elements that increase the complexity and plasticity of the hippocampal circuitry. Numerous lines of evidence show that physical activity and environmental enrichment (EE) are among the most potent positive regulators of AHN. Given that neural plasticity is markedly decreased in many neurodegenerative diseases, the therapeutic potential of making certain lifestyle changes, such as increasing physical activity, is being recognised in several non-pharmacologic strategies seeking to slow down or prevent the progression of these diseases. This review article summarizes current evidence supporting the putative therapeutic potential of EE and physical exercise to increase AHN and hippocampal plasticity both under physiological and pathological circumstances, with a special emphasis on neurodegenerative diseases and AD.
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Affiliation(s)
- María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSIC-UAM, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases CIBERNED, Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
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20
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Beigi B, Shahidi S, Komaki A, Sarihi A, Hashemi-Firouzi N. Pretraining hippocampal stimulation of melatonin type 2 receptors can improve memory acquisition in rats. Int J Neurosci 2018; 129:492-500. [PMID: 30431374 DOI: 10.1080/00207454.2018.1545770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Learning and memory are among the most important cognitive functions of the brain. Melatonin receptor type 2 (MT2R) is located in the hippocampus and participates in learning and memory processes. In the present study, we examined the role of hippocampal MT2R activation in the acquisition, consolidation, and retrieval of learning and memory in novel object recognition (NOR) and passive avoidance (PA) tasks. METHODS IIK7 (0.03, 0.3, and 3 μg/μl/side), as a selective MT2R agonist, or vehicle was injected bilaterally into the dentate gyrus (DG) region of the hippocampus in rats five minutes before training, immediately after training, and five minutes before the retrieval-behavioral tasks, respectively. The discrimination index (DI) was measured in the NOR task, while step-through latency in acquisition (STLa), number of trials to acquisition (NOT), step-through latency in the retention trial (STLr), and time spent in the dark compartment (TDC) were determined in the PA task. RESULTS The pretraining intrahippocampal injection of IIK7 at all doses significantly improved acquisition in the PA task. On the other hand, the posttraining intrahippocampal administration of IIK7 had no significant effects on consolidation. The preretrieval intrahippocampal injection of IIK7 at different doses attenuated the retrieval of memory. However, the NOR data showed that the intrahippocampal injection of IIK7 at different doses had no significant effects on the acquisition, consolidation, or retrieval in this task. DISCUSSION Based on the findings, stimulation of MT2R could improve acquisition, whereas it had no effects on consolidation. It could impair retrieval in the PA task, while it had no effects on object recognition in rats.
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Affiliation(s)
- Bita Beigi
- a Neurophysiology Research Center , Hamadan University of Medical Science , Hamadan , Iran
| | - Siamak Shahidi
- a Neurophysiology Research Center , Hamadan University of Medical Science , Hamadan , Iran
| | - Alireza Komaki
- a Neurophysiology Research Center , Hamadan University of Medical Science , Hamadan , Iran
| | - Abdolrahman Sarihi
- a Neurophysiology Research Center , Hamadan University of Medical Science , Hamadan , Iran
| | - Nasrin Hashemi-Firouzi
- a Neurophysiology Research Center , Hamadan University of Medical Science , Hamadan , Iran
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21
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Huckleberry KA, Shue F, Copeland T, Chitwood RA, Yin W, Drew MR. Dorsal and ventral hippocampal adult-born neurons contribute to context fear memory. Neuropsychopharmacology 2018; 43:2487-2496. [PMID: 29941977 PMCID: PMC6180107 DOI: 10.1038/s41386-018-0109-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/06/2018] [Accepted: 05/29/2018] [Indexed: 12/16/2022]
Abstract
The hippocampus contains one of the few neurogenic niches within the adult brain-the subgranular zone of the dentate gyrus. The functional significance of adult-born neurons in this region has been characterized using context fear conditioning, a Pavlovian paradigm in which animals learn to associate a location with danger. Ablation or silencing of adult-born neurons impairs both acquisition and recall of contextual fear conditioning, suggesting that these neurons contribute importantly to hippocampal memory. Lesion studies indicate that CFC depends on neural activity in both the dorsal and ventral hippocampus, subregions with unique extrahippocampal connectivity and behavioral functions. Because most studies of adult neurogenesis have relied on methods that permanently ablate neurogenesis throughout the entire hippocampus, little is known about how the function of adult-born neurons varies along the dorsal-ventral axis. Using a Nestin-CreERT2 mouse line to target the optogenetic silencer Archaerhodopsin to adult-born neurons, we compared the contribution of dorsal and ventral adult-born neurons to acquisition, recall, and generalization of CFC. Acquisition of CFC was impaired when either dorsal or ventral adult-born neurons were silenced during training. Silencing dorsal or ventral adult-born neurons during test sessions decreased context-evoked freezing but did not impair freezing in a hippocampus-independent tone-shock freezing paradigm. Silencing adult-born neurons modestly reduced generalization of fear. Our data indicate that adult-born neurons in the dorsal and ventral hippocampus contribute to both memory acquisition and recall. The comparatively large behavioral effects of silencing a small number of adult-born neurons suggest that these neurons make a unique and powerful contribution to hippocampal function.
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Affiliation(s)
- Kylie A. Huckleberry
- 0000 0004 1936 9924grid.89336.37Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX USA
| | - Francis Shue
- 0000 0004 1936 9924grid.89336.37Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX USA
| | - Taylor Copeland
- 0000 0004 1936 9924grid.89336.37Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX USA
| | - Raymond A. Chitwood
- 0000 0004 1936 9924grid.89336.37Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX USA
| | - Weiling Yin
- 0000 0004 1936 9924grid.89336.37Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX USA
| | - Michael R. Drew
- 0000 0004 1936 9924grid.89336.37Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX USA
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22
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Rolls ET. The storage and recall of memories in the hippocampo-cortical system. Cell Tissue Res 2018; 373:577-604. [PMID: 29218403 PMCID: PMC6132650 DOI: 10.1007/s00441-017-2744-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/12/2017] [Indexed: 02/07/2023]
Abstract
A quantitative computational theory of the operation of the hippocampus as an episodic memory system is described. The CA3 system operates as a single attractor or autoassociation network (1) to enable rapid one-trial associations between any spatial location (place in rodents or spatial view in primates) and an object or reward and (2) to provide for completion of the whole memory during recall from any part. The theory is extended to associations between time and object or reward to implement temporal order memory, which is also important in episodic memory. The dentate gyrus performs pattern separation by competitive learning to create sparse representations producing, for example, neurons with place-like fields from entorhinal cortex grid cells. The dentate granule cells generate, by the very small number of mossy fibre connections to CA3, a randomizing pattern separation effect that is important during learning but not recall and that separates out the patterns represented by CA3 firing as being very different from each other. This is optimal for an unstructured episodic memory system in which each memory must be kept distinct from other memories. The direct perforant path input to CA3 is quantitatively appropriate for providing the cue for recall in CA3 but not for learning. The CA1 recodes information from CA3 to set up associatively learned backprojections to the neocortex to allow the subsequent retrieval of information to the neocortex, giving a quantitative account of the large number of hippocampo-neocortical and neocortical-neocortical backprojections. Tests of the theory including hippocampal subregion analyses and hippocampal NMDA receptor knockouts are described and support the theory.
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Affiliation(s)
- Edmund T Rolls
- Oxford Centre for Computational Neuroscience, Oxford, England.
- Department of Computer Science, University of Warwick, Coventry, England.
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23
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Mu D, Xu Y, Zhao T, Watanabe K, Xiao Z, Ye H. Cntn6 deficiency impairs allocentric navigation in mice. Brain Behav 2018; 8:e00969. [PMID: 30106251 PMCID: PMC5991572 DOI: 10.1002/brb3.969] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/06/2023] Open
Abstract
INTRODUCTION CNTN6 is an immunoglobulin domain-containing cell adhesion molecule that belongs to the contactin family. It is involved in the development of the nervous system. We aim to determine the effect of Cntn6 deficiency on the allocentric navigation in mice. METHODS We recorded the travel distance and escape time of wild-type and Cntn6 mutant male and female mice in the Morris water maze task according to the protocol. RESULTS There was hardly any Cntn6 expression in the hippocampus of postnatal day 0 (P0) mice, while obvious Cntn6 expression was present in the hippocampal CA1 region of the P7 mice. During the acquisition period of Morris water maze task (Day 1 to 4), Cntn6-/- male mice failed to shorten the escape time to reach platform on the third day, while the travel distance to platform was not significantly different. There was no significant difference in both escape time and travel distance to the platform among all female subjects. In the probe trial test (Day 5), spatial memory of the female mutant mice was mildly affected, while Cntn6-/- male mice were normal. In the spatial relearning test (Day 7 to 10), Cntn6-/- male mice showed no difference in escape time to the platform compared to the wild-type male mice, while Cntn6 deficient female mice required shorter escape time to travel to the platform on day 7, day 8, and day 10. CONCLUSIONS Cntn6 is expressed in the developing hippocampus in mice. Cntn6 deficiency affects spatial learning and memory, indicating that Cntn6 plays a role in the development of hippocampus and affects allocentric navigation of the animals.
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Affiliation(s)
- Di Mu
- Department of Medical Genetics and Developmental BiologySchool of Basic Medical SciencesBeijing Institute for Brain DisordersCenter of SchizophreniaCapital Medical UniversityBeijingChina
| | - Yiliang Xu
- Department of Medical Genetics and Developmental BiologySchool of Basic Medical SciencesBeijing Institute for Brain DisordersCenter of SchizophreniaCapital Medical UniversityBeijingChina
| | - Tian Zhao
- Department of Medical Genetics and Developmental BiologySchool of Basic Medical SciencesBeijing Institute for Brain DisordersCenter of SchizophreniaCapital Medical UniversityBeijingChina
| | - Kazutada Watanabe
- Department of BioengineeringNagaoka University of TechnologyNagaokaNiigataJapan
| | - Zhi‐Cheng Xiao
- The Key Laboratory of Stem Cell and Regenerative MedicineInstitute of Molecular and Clinical MedicineKunming Medical UniversityKunmingChina
- Department of Anatomy and Developmental BiologyMonash UniversityClaytonMELAustralia
| | - Haihong Ye
- Department of Medical Genetics and Developmental BiologySchool of Basic Medical SciencesBeijing Institute for Brain DisordersCenter of SchizophreniaCapital Medical UniversityBeijingChina
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24
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Kassab R, Alexandre F. Pattern separation in the hippocampus: distinct circuits under different conditions. Brain Struct Funct 2018; 223:2785-2808. [PMID: 29637298 DOI: 10.1007/s00429-018-1659-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/26/2018] [Indexed: 10/17/2022]
Abstract
Pattern separation is a fundamental hippocampal process thought to be critical for distinguishing similar episodic memories, and has long been recognized as a natural function of the dentate gyrus (DG), supporting autoassociative learning in CA3. Understanding how neural circuits within the DG-CA3 network mediate this process has received much interest, yet the exact mechanisms behind remain elusive. Here, we argue for the case that sparse coding is necessary but not sufficient to ensure efficient separation and, alternatively, propose a possible interaction of distinct circuits which, nevertheless, act in synergy to produce a unitary function of pattern separation. The proposed circuits involve different functional granule-cell populations, a primary population mediates sparsification and provides recurrent excitation to the other populations which are related to additional pattern separation mechanisms with higher degrees of robustness against interference in CA3. A variety of top-down and bottom-up factors, such as motivation, emotion, and pattern similarity, control the selection of circuitry depending on circumstances. According to this framework, a computational model is implemented and tested against model variants in a series of numerical simulations and biological experiments. The results demonstrate that the model combines fast learning, robust pattern separation and high storage capacity. It also accounts for the controversy around the involvement of the DG during memory recall, explains other puzzling findings, and makes predictions that can inform future investigations.
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Affiliation(s)
- Randa Kassab
- INRIA, Bordeaux Sud-Ouest, Talence, France. .,Institut des Maladies Neurodégénératives, University of Bordeaux, CNRS UMR 5293-Case 28, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, 33076, Bordeaux, France. .,LaBRI, UMR 5800, CNRS, Bordeaux INP, University of Bordeaux, Talence, France.
| | - Frédéric Alexandre
- INRIA, Bordeaux Sud-Ouest, Talence, France.,Institut des Maladies Neurodégénératives, University of Bordeaux, CNRS UMR 5293-Case 28, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, 33076, Bordeaux, France.,LaBRI, UMR 5800, CNRS, Bordeaux INP, University of Bordeaux, Talence, France
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25
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Weng FJ, Garcia RI, Lutzu S, Alviña K, Zhang Y, Dushko M, Ku T, Zemoura K, Rich D, Garcia-Dominguez D, Hung M, Yelhekar TD, Sørensen AT, Xu W, Chung K, Castillo PE, Lin Y. Npas4 Is a Critical Regulator of Learning-Induced Plasticity at Mossy Fiber-CA3 Synapses during Contextual Memory Formation. Neuron 2018; 97:1137-1152.e5. [PMID: 29429933 PMCID: PMC5843542 DOI: 10.1016/j.neuron.2018.01.026] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 11/26/2017] [Accepted: 01/11/2018] [Indexed: 11/18/2022]
Abstract
Synaptic connections between hippocampal mossy fibers (MFs) and CA3 pyramidal neurons are essential for contextual memory encoding, but the molecular mechanisms regulating MF-CA3 synapses during memory formation and the exact nature of this regulation are poorly understood. Here we report that the activity-dependent transcription factor Npas4 selectively regulates the structure and strength of MF-CA3 synapses by restricting the number of their functional synaptic contacts without affecting the other synaptic inputs onto CA3 pyramidal neurons. Using an activity-dependent reporter, we identified CA3 pyramidal cells that were activated by contextual learning and found that MF inputs on these cells were selectively strengthened. Deletion of Npas4 prevented both contextual memory formation and this learning-induced synaptic modification. We further show that Npas4 regulates MF-CA3 synapses by controlling the expression of the polo-like kinase Plk2. Thus, Npas4 is a critical regulator of experience-dependent, structural, and functional plasticity at MF-CA3 synapses during contextual memory formation.
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Affiliation(s)
- Feng-Ju Weng
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Rodrigo I Garcia
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Stefano Lutzu
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Karina Alviña
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Yuxiang Zhang
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Margaret Dushko
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Taeyun Ku
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA; Institute for Medical Engineering and Science, MIT, Cambridge, MA, USA
| | - Khaled Zemoura
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA
| | - David Rich
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Dario Garcia-Dominguez
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Matthew Hung
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Tushar D Yelhekar
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Andreas Toft Sørensen
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Weifeng Xu
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA
| | - Kwanghun Chung
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA; Institute for Medical Engineering and Science, MIT, Cambridge, MA, USA; Department of Chemical Engineering, MIT, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences and Technology, MIT, Cambridge, MA, USA
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Yingxi Lin
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA.
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Unfolding the cognitive map: The role of hippocampal and extra-hippocampal substrates based on a systems analysis of spatial processing. Neurobiol Learn Mem 2018; 147:90-119. [DOI: 10.1016/j.nlm.2017.11.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 01/03/2023]
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Blakemore LJ, Trombley PQ. Zinc as a Neuromodulator in the Central Nervous System with a Focus on the Olfactory Bulb. Front Cell Neurosci 2017; 11:297. [PMID: 29033788 PMCID: PMC5627021 DOI: 10.3389/fncel.2017.00297] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/06/2017] [Indexed: 12/19/2022] Open
Abstract
The olfactory bulb (OB) is central to the sense of smell, as it is the site of the first synaptic relay involved in the processing of odor information. Odor sensations are first transduced by olfactory sensory neurons (OSNs) before being transmitted, by way of the OB, to higher olfactory centers that mediate olfactory discrimination and perception. Zinc is a common trace element, and it is highly concentrated in the synaptic vesicles of subsets of glutamatergic neurons in some brain regions including the hippocampus and OB. In addition, zinc is contained in the synaptic vesicles of some glycinergic and GABAergic neurons. Thus, zinc released from synaptic vesicles is available to modulate synaptic transmission mediated by excitatory (e.g., N-methyl-D aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)) and inhibitory (e.g., gamma-aminobutyric acid (GABA), glycine) amino acid receptors. Furthermore, extracellular zinc can alter the excitability of neurons through effects on a variety of voltage-gated ion channels. Consistent with the notion that zinc acts as a regulator of neuronal activity, we and others have shown zinc modulation (inhibition and/or potentiation) of amino acid receptors and voltage-gated ion channels expressed by OB neurons. This review summarizes the locations and release of vesicular zinc in the central nervous system (CNS), including in the OB. It also summarizes the effects of zinc on various amino acid receptors and ion channels involved in regulating synaptic transmission and neuronal excitability, with a special emphasis on the actions of zinc as a neuromodulator in the OB. An understanding of how neuroactive substances such as zinc modulate receptors and ion channels expressed by OB neurons will increase our understanding of the roles that synaptic circuits in the OB play in odor information processing and transmission.
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Affiliation(s)
- Laura J Blakemore
- Program in Neuroscience, Florida State UniversityTallahassee, FL, United States.,Department of Biological Science, Florida State UniversityTallahassee, FL, United States
| | - Paul Q Trombley
- Program in Neuroscience, Florida State UniversityTallahassee, FL, United States.,Department of Biological Science, Florida State UniversityTallahassee, FL, United States
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Bernier BE, Lacagnina AF, Ayoub A, Shue F, Zemelman BV, Krasne FB, Drew MR. Dentate Gyrus Contributes to Retrieval as well as Encoding: Evidence from Context Fear Conditioning, Recall, and Extinction. J Neurosci 2017; 37:6359-6371. [PMID: 28546308 PMCID: PMC5490069 DOI: 10.1523/jneurosci.3029-16.2017] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 04/10/2017] [Accepted: 05/20/2017] [Indexed: 11/21/2022] Open
Abstract
Dentate gyrus (DG) is widely thought to provide a teaching signal that enables hippocampal encoding of memories, but its role during retrieval is poorly understood. Some data and models suggest that DG plays no role in retrieval; others encourage the opposite conclusion. To resolve this controversy, we evaluated the effects of optogenetic inhibition of dorsal DG during context fear conditioning, recall, generalization, and extinction in male mice. We found that (1) inhibition during training impaired context fear acquisition; (2) inhibition during recall did not impair fear expression in the training context, unless mice had to distinguish between similar feared and neutral contexts; (3) inhibition increased generalization of fear to an unfamiliar context that was similar to a feared one and impaired fear expression in the conditioned context when it was similar to a neutral one; and (4) inhibition impaired fear extinction. These effects, as well as several seemingly contradictory published findings, could be reproduced by BACON (Bayesian Context Fear Algorithm), a physiologically realistic hippocampal model positing that acquisition and retrieval both involve coordinated activity in DG and CA3. Our findings thus suggest that DG contributes to retrieval and extinction, as well as to the initial establishment of context fear.SIGNIFICANCE STATEMENT Despite abundant evidence that the hippocampal dentate gyrus (DG) plays a critical role in memory, it remains unclear whether the role of DG relates to memory acquisition or retrieval. Using contextual fear conditioning and optogenetic inhibition, we show that DG contributes to both of these processes. Using computational simulations, we identify specific mechanisms through which the suppression of DG affects memory performance. Finally, we show that DG contributes to fear extinction learning, a process in which learned fear is attenuated through exposures to a fearful context in the absence of threat. Our data resolve a long-standing question about the role of DG in memory and provide insight into how disorders affecting DG, including aging, stress, and depression, influence cognitive processes.
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Affiliation(s)
- Brian E Bernier
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712, and
| | - Anthony F Lacagnina
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712, and
| | - Adam Ayoub
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712, and
| | - Francis Shue
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712, and
| | - Boris V Zemelman
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712, and
| | - Franklin B Krasne
- Department of Psychology, University of California at Los Angeles, Los Angeles, California 90095
| | - Michael R Drew
- Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, Texas 78712, and
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29
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Rebola N, Carta M, Mulle C. Operation and plasticity of hippocampal CA3 circuits: implications for memory encoding. Nat Rev Neurosci 2017; 18:208-220. [DOI: 10.1038/nrn.2017.10] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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30
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Alaverdashvili M, Paterson PG. Mapping the dynamics of cortical neuroplasticity of skilled motor learning using micro X-ray fluorescence and histofluorescence imaging of zinc in the rat. Behav Brain Res 2016; 318:52-60. [PMID: 27840249 DOI: 10.1016/j.bbr.2016.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/26/2016] [Accepted: 11/01/2016] [Indexed: 11/26/2022]
Abstract
Synchrotron-based X-ray fluorescence imaging (XFI) of zinc (Zn) has been recently implemented to understand the efficiency of various therapeutic interventions targeting post-stroke neuroprotection and neuroplasticity. However, it is uncertain if micro XFI can resolve neuroplasticity-induced changes. Thus, we explored if learning-associated behavioral changes would be accompanied by changes in cortical Zn concentration measured by XFI in healthy adult rats. Proficiency in a skilled reach-to-eat task during early and late stages of motor learning served as a functional measure of neuroplasticity. c-Fos protein and vesicular Zn expression were employed as indirect neuronal measures of brain plasticity. A total Zn map (20×20×30μm3 resolution) generated by micro XFI failed to reflect increases in either c-Fos or vesicular Zn in the motor cortex contralateral to the trained forelimb or improved proficiency in the skilled reaching task. Remarkably, vesicular Zn increased in the late stage of motor learning along with a concurrent decrease in the number of c-fos-ip neurons relative to the early stage of motor learning. This inverse dynamics of c-fos and vesicular Zn level as the motor skill advances suggest that a qualitatively different neural population, comprised of fewer active but more efficiently connected neurons, supports a skilled action in the late versus early stage of motor learning. The lack of sensitivity of the XFI-generated Zn map to visualize the plasticity-associated changes in vesicular Zn suggests that the Zn level measured by micro XFI should not be used as a surrogate marker of neuroplasticity in response to the acquisition of skilled motor actions. Nanoscopic XFI could be explored in future as a means of imaging these subtle physiological changes.
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Affiliation(s)
- Mariam Alaverdashvili
- Neuroscience Research Cluster, Saskatoon, SK, S7N 5E5, Canada; College of Pharmacy and Nutrition, Saskatoon, SK, S7N 5E5, Canada; College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
| | - Phyllis G Paterson
- Neuroscience Research Cluster, Saskatoon, SK, S7N 5E5, Canada; College of Pharmacy and Nutrition, Saskatoon, SK, S7N 5E5, Canada
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31
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Structural synaptic plasticity in the hippocampus induced by spatial experience and its implications in information processing. NEUROLOGÍA (ENGLISH EDITION) 2016. [DOI: 10.1016/j.nrleng.2012.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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32
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Villanueva-Castillo C, Tecuatl C, Herrera-López G, Galván EJ. Aging-related impairments of hippocampal mossy fibers synapses on CA3 pyramidal cells. Neurobiol Aging 2016; 49:119-137. [PMID: 27794263 DOI: 10.1016/j.neurobiolaging.2016.09.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/15/2016] [Accepted: 09/17/2016] [Indexed: 11/16/2022]
Abstract
The network interaction between the dentate gyrus and area CA3 of the hippocampus is responsible for pattern separation, a process that underlies the formation of new memories, and which is naturally diminished in the aged brain. At the cellular level, aging is accompanied by a progression of biochemical modifications that ultimately affects its ability to generate and consolidate long-term potentiation. Although the synapse between dentate gyrus via the mossy fibers (MFs) onto CA3 neurons has been subject of extensive studies, the question of how aging affects the MF-CA3 synapse is still unsolved. Extracellular and whole-cell recordings from acute hippocampal slices of aged Wistar rats (34 ± 2 months old) show that aging is accompanied by a reduction in the interneuron-mediated inhibitory mechanisms of area CA3. Several MF-mediated forms of short-term plasticity, MF long-term potentiation and at least one of the critical signaling cascades necessary for potentiation are also compromised in the aged brain. An analysis of the spontaneous glutamatergic and gamma-aminobutyric acid-mediated currents on CA3 cells reveal a dramatic alteration in amplitude and frequency of the nonevoked events. CA3 cells also exhibited increased intrinsic excitability. Together, these results demonstrate that aging is accompanied by a decrease in the GABAergic inhibition, reduced expression of short- and long-term forms of synaptic plasticity, and increased intrinsic excitability.
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Affiliation(s)
| | - Carolina Tecuatl
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, México
| | | | - Emilio J Galván
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, México.
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33
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The effects of hormones and physical exercise on hippocampal structural plasticity. Front Neuroendocrinol 2016; 41:23-43. [PMID: 26989000 DOI: 10.1016/j.yfrne.2016.03.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/02/2016] [Accepted: 03/08/2016] [Indexed: 01/22/2023]
Abstract
The hippocampus plays an integral role in certain aspects of cognition. Hippocampal structural plasticity and in particular adult hippocampal neurogenesis can be influenced by several intrinsic and extrinsic factors. Here we review how hormones (i.e., intrinsic modulators) and physical exercise (i.e., an extrinsic modulator) can differentially modulate hippocampal plasticity in general and adult hippocampal neurogenesis in particular. Specifically, we provide an overview of the effects of sex hormones, stress hormones, and metabolic hormones on hippocampal structural plasticity and adult hippocampal neurogenesis. In addition, we also discuss how physical exercise modulates these forms of hippocampal plasticity, giving particular emphasis on how this modulation can be affected by variables such as exercise regime, duration, and intensity. Understanding the neurobiological mechanisms underlying the modulation of hippocampal structural plasticity by intrinsic and extrinsic factors will impact the design of new therapeutic approaches aimed at restoring hippocampal plasticity following brain injury or neurodegeneration.
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34
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Madroñal N, Delgado-García JM, Fernández-Guizán A, Chatterjee J, Köhn M, Mattucci C, Jain A, Tsetsenis T, Illarionova A, Grinevich V, Gross CT, Gruart A. Rapid erasure of hippocampal memory following inhibition of dentate gyrus granule cells. Nat Commun 2016; 7:10923. [PMID: 26988806 PMCID: PMC4802048 DOI: 10.1038/ncomms10923] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/27/2016] [Indexed: 11/22/2022] Open
Abstract
The hippocampus is critical for the acquisition and retrieval of episodic and contextual memories. Lesions of the dentate gyrus, a principal input of the hippocampus, block memory acquisition, but it remains unclear whether this region also plays a role in memory retrieval. Here we combine cell-type specific neural inhibition with electrophysiological measurements of learning-associated plasticity in behaving mice to demonstrate that dentate gyrus granule cells are not required for memory retrieval, but instead have an unexpected role in memory maintenance. Furthermore, we demonstrate the translational potential of our findings by showing that pharmacological activation of an endogenous inhibitory receptor expressed selectively in dentate gyrus granule cells can induce a rapid loss of hippocampal memory. These findings open a new avenue for the targeted erasure of episodic and contextual memories. Dentate gyrus (DG) is critical for memory formation in the hippocampus but its role in memory retrieval is unclear. Here, Gross and colleagues, show that granule cells in DG are not required for memory retrieval but for maintenance, and inhibiting them with a drug leads to rapid loss of memory.
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Affiliation(s)
- Noelia Madroñal
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), via Ramarini 32, Monterotondo 00015, Italy.,Division of Neuroscience, University Pablo Olavide, Carretera de Utrera-km 1, Sevilla 41013, Spain
| | - José M Delgado-García
- Division of Neuroscience, University Pablo Olavide, Carretera de Utrera-km 1, Sevilla 41013, Spain
| | - Azahara Fernández-Guizán
- Division of Neuroscience, University Pablo Olavide, Carretera de Utrera-km 1, Sevilla 41013, Spain
| | - Jayanta Chatterjee
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Maja Köhn
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Camilla Mattucci
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), via Ramarini 32, Monterotondo 00015, Italy
| | - Apar Jain
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), via Ramarini 32, Monterotondo 00015, Italy
| | - Theodoros Tsetsenis
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), via Ramarini 32, Monterotondo 00015, Italy
| | - Anna Illarionova
- Schaller Research Group on Neuropeptides, German Cancer Research Center DKFZ, Central Institute of Mental Health, CellNetwork Cluster of Excellence, University of Heidelberg, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Valery Grinevich
- Schaller Research Group on Neuropeptides, German Cancer Research Center DKFZ, Central Institute of Mental Health, CellNetwork Cluster of Excellence, University of Heidelberg, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Cornelius T Gross
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), via Ramarini 32, Monterotondo 00015, Italy
| | - Agnès Gruart
- Division of Neuroscience, University Pablo Olavide, Carretera de Utrera-km 1, Sevilla 41013, Spain
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35
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Scarr E, Udawela M, Greenough MA, Neo J, Suk Seo M, Money TT, Upadhyay A, Bush AI, Everall IP, Thomas EA, Dean B. Increased cortical expression of the zinc transporter SLC39A12 suggests a breakdown in zinc cellular homeostasis as part of the pathophysiology of schizophrenia. NPJ SCHIZOPHRENIA 2016; 2:16002. [PMID: 27336053 PMCID: PMC4898896 DOI: 10.1038/npjschz.2016.2] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 01/14/2016] [Accepted: 01/20/2016] [Indexed: 11/09/2022]
Abstract
Our expression microarray studies showed messenger RNA (mRNA) for solute carrier family 39 (zinc transporter), member 12 (SLC39A12) was higher in dorsolateral prefrontal cortex from subjects with schizophrenia (Sz) in comparison with controls. To better understand the significance of these data we ascertained whether SLC39A12 mRNA was altered in a number of cortical regions (Brodmann’s area (BA) 8, 9, 44) from subjects with Sz, in BA 9 from subjects with mood disorders and in rats treated with antipsychotic drugs. In addition, we determined whether inducing the expression of SLC39A12 resulted in an increased cellular zinc uptake. SLC39A12 variant 1 and 2 mRNA was measured using quantitative PCR. Zinc uptake was measured in CHO cells transfected with human SLC39A12 variant 1 and 2. In Sz, compared with controls, SLC39A12 variant 1 and 2 mRNA was higher in all cortical regions studied. The were no differences in levels of mRNA for either variant of SLC39A12 in BA 9 from subjects with mood disorders and levels of mRNA for Slc39a12 was not different in the cortex of rats treated with antipsychotic drugs. Finally, expressing both variants in CHO-K1 cells was associated with an increase in radioactive zinc uptake. As increased levels of murine Slc39a12 mRNA has been shown to correlate with increasing cellular zinc uptake, our data would be consistent with the possibility of a dysregulated zinc homeostasis in the cortex of subjects with schizophrenia due to altered expression of SLC39A12.
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Affiliation(s)
- Elizabeth Scarr
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; Department of Psychaitry, University of Melbourne, Melbourne, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia
| | - Madhara Udawela
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia
| | - Mark A Greenough
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health , Parkville, VIC, Australia
| | - Jaclyn Neo
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia
| | - Myoung Suk Seo
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health , Parkville, VIC, Australia
| | - Tammie T Money
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; Department of Psychaitry, University of Melbourne, Melbourne, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia; Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Aradhana Upadhyay
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia
| | - Ashley I Bush
- CRC for Mental Health, Carlton South, VIC, Australia; Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Ian P Everall
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; Department of Psychaitry, University of Melbourne, Melbourne, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia
| | - Elizabeth A Thomas
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute , La Jolla, CA, USA
| | - Brian Dean
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia; Department of Psychaitry, University of Melbourne, Melbourne, VIC, Australia; CRC for Mental Health, Carlton South, VIC, Australia
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Johnston ST, Shtrahman M, Parylak S, Gonçalves JT, Gage FH. Paradox of pattern separation and adult neurogenesis: A dual role for new neurons balancing memory resolution and robustness. Neurobiol Learn Mem 2015; 129:60-8. [PMID: 26549627 DOI: 10.1016/j.nlm.2015.10.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/22/2015] [Accepted: 10/27/2015] [Indexed: 01/31/2023]
Abstract
Hippocampal adult neurogenesis is thought to subserve pattern separation, the process by which similar patterns of neuronal inputs are transformed into distinct neuronal representations, permitting the discrimination of highly similar stimuli in hippocampus-dependent tasks. However, the mechanism by which immature adult-born dentate granule neurons cells (abDGCs) perform this function remains unknown. Two theories of abDGC function, one by which abDGCs modulate and sparsify activity in the dentate gyrus and one by which abDGCs act as autonomous coding units, are generally suggested to be mutually exclusive. This review suggests that these two mechanisms work in tandem to dynamically regulate memory resolution while avoiding memory interference and maintaining memory robustness.
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Affiliation(s)
- Stephen T Johnston
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - Matthew Shtrahman
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - Sarah Parylak
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - J Tiago Gonçalves
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - Fred H Gage
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States.
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Mahmmoud RR, Sase S, Aher YD, Sase A, Gröger M, Mokhtar M, Höger H, Lubec G. Spatial and Working Memory Is Linked to Spine Density and Mushroom Spines. PLoS One 2015; 10:e0139739. [PMID: 26469788 PMCID: PMC4607435 DOI: 10.1371/journal.pone.0139739] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 09/15/2015] [Indexed: 11/19/2022] Open
Abstract
Background Changes in synaptic structure and efficacy including dendritic spine number and morphology have been shown to underlie neuronal activity and size. Moreover, the shapes of individual dendritic spines were proposed to correlate with their capacity for structural change. Spine numbers and morphology were reported to parallel memory formation in the rat using a water maze but, so far, there is no information on spine counts or shape in the radial arm maze (RAM), a frequently used paradigm for the evaluation of complex memory formation in the rodent. Methods 24 male Sprague-Dawley rats were divided into three groups, 8 were trained, 8 remained untrained in the RAM and 8 rats served as cage controls. Dendritic spine numbers and individual spine forms were counted in CA1, CA3 areas and dentate gyrus of hippocampus using a DIL dye method with subsequent quantification by the Neuronstudio software and the image J program. Results Working memory errors (WME) and latency in the RAM were decreased along the training period indicating that animals performed the task. Total spine density was significantly increased following training in the RAM as compared to untrained rats and cage controls. The number of mushroom spines was significantly increased in the trained as compared to untrained and cage controls. Negative significant correlations between spine density and WME were observed in CA1 basal dendrites and in CA3 apical and basal dendrites. In addition, there was a significant negative correlation between spine density and latency in CA3 basal dendrites. Conclusion The study shows that spine numbers are significantly increased in the trained group, an observation that may suggest the use of this method representing a morphological parameter for memory formation studies in the RAM. Herein, correlations between WME and latency in the RAM and spine density revealed a link between spine numbers and performance in the RAM.
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Affiliation(s)
- Rasha Refaat Mahmmoud
- Department of Pharmaceutical Chemistry, University of Vienna, 1090 Vienna, Austria
- Department of Pediatrics, Faculty of Medicine, Assuit University, Assuit, Egypt
| | - Sunetra Sase
- Department of Pharmaceutical Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Yogesh D. Aher
- Department of Pharmaceutical Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Ajinkya Sase
- Department of Pharmaceutical Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Marion Gröger
- CF Imaging, Medical University of Vienna, 1090 Vienna, Austria
| | - Maher Mokhtar
- Department of Pediatrics, Faculty of Medicine, Assuit University, Assuit, Egypt
| | - Harald Höger
- Core Unit of Biomedical Research, Division of Laboratory Animal Science and Genetics, Medical University of Vienna, Brauhausgasse 34, A-2325 Himberg, Austria
| | - Gert Lubec
- Department of Pharmaceutical Chemistry, University of Vienna, 1090 Vienna, Austria
- * E-mail:
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Involvement of Adult Hippocampal Neurogenesis in Learning and Forgetting. Neural Plast 2015; 2015:717958. [PMID: 26380120 PMCID: PMC4561984 DOI: 10.1155/2015/717958] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 03/12/2015] [Accepted: 03/31/2015] [Indexed: 12/20/2022] Open
Abstract
Adult hippocampal neurogenesis is a process involving the continuous generation of newborn neurons in the hippocampus of adult animals. Mounting evidence has suggested that hippocampal neurogenesis contributes to some forms of hippocampus-dependent learning and memory; however, the detailed mechanism concerning how this small number of newborn neurons could affect learning and memory remains unclear. In this review, we discuss the relationship between adult-born neurons and learning and memory, with a highlight on recently discovered potential roles of neurogenesis in pattern separation and forgetting.
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Carasatorre M, Ochoa-Alvarez A, Velázquez-Campos G, Lozano-Flores C, Ramírez-Amaya V, Díaz-Cintra SY. Hippocampal Synaptic Expansion Induced by Spatial Experience in Rats Correlates with Improved Information Processing in the Hippocampus. PLoS One 2015; 10:e0132676. [PMID: 26244549 PMCID: PMC4526663 DOI: 10.1371/journal.pone.0132676] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 06/18/2015] [Indexed: 12/31/2022] Open
Abstract
Spatial water maze (WM) overtraining induces hippocampal mossy fiber (MF) expansion, and it has been suggested that spatial pattern separation depends on the MF pathway. We hypothesized that WM experience inducing MF expansion in rats would improve spatial pattern separation in the hippocampal network. We first tested this by using the the delayed non-matching to place task (DNMP), in animals that had been previously trained on the water maze (WM) and found that these animals, as well as animals treated as swim controls (SC), performed better than home cage control animals the DNMP task. The "catFISH" imaging method provided neurophysiological evidence that hippocampal pattern separation improved in animals treated as SC, and this improvement was even clearer in animals that experienced the WM training. Moreover, these behavioral treatments also enhance network reliability and improve partial pattern separation in CA1 and pattern completion in CA3. By measuring the area occupied by synaptophysin staining in both the stratum oriens and the stratun lucidum of the distal CA3, we found evidence of structural synaptic plasticity that likely includes MF expansion. Finally, the measures of hippocampal network coding obtained with catFISH correlate significantly with the increased density of synaptophysin staining, strongly suggesting that structural synaptic plasticity in the hippocampus induced by the WM and SC experience is related to the improvement of spatial information processing in the hippocampus.
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Affiliation(s)
- Mariana Carasatorre
- Department of "Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología", Universidad Nacional Autónoma de México, Querétaro, México
| | - Adrian Ochoa-Alvarez
- Department of "Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología", Universidad Nacional Autónoma de México, Querétaro, México
| | - Giovanna Velázquez-Campos
- Department of "Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México", Querétaro, México; Departament of "Microbiología, Maestría en Neurometabolismo & Maestría en Nutrición Humana, Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Querétaro, México
| | - Carlos Lozano-Flores
- Department of "Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología", Universidad Nacional Autónoma de México, Querétaro, México
| | - Víctor Ramírez-Amaya
- Department of "Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología", Universidad Nacional Autónoma de México, Querétaro, México
| | - Sofía Y Díaz-Cintra
- Departament of "Microbiología, Maestría en Neurometabolismo & Maestría en Nutrición Humana, Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Querétaro, México
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40
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Rolls ET. Pattern separation, completion, and categorisation in the hippocampus and neocortex. Neurobiol Learn Mem 2015; 129:4-28. [PMID: 26190832 DOI: 10.1016/j.nlm.2015.07.008] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/02/2015] [Accepted: 07/11/2015] [Indexed: 12/22/2022]
Abstract
The mechanisms for pattern completion and pattern separation are described in the context of a theory of hippocampal function in which the hippocampal CA3 system operates as a single attractor or autoassociation network to enable rapid, one-trial, associations between any spatial location (place in rodents, or spatial view in primates) and an object or reward, and to provide for completion of the whole memory during recall from any part. The factors important in the pattern completion in CA3 and also a large number of independent memories stored in CA3 include: a sparse distributed representation, representations that are independent due to the randomizing effect of the mossy fibres, heterosynaptic long-term depression as well as long-term potentiation in the recurrent collateral synapses, and diluted connectivity to minimize the number of multiple synapses between any pair of CA3 neurons which otherwise distort the basins of attraction. Recall of information from CA3 is implemented by the entorhinal cortex perforant path synapses to CA3 cells, which in acting as a pattern associator allow some pattern generalization. Pattern separation is performed in the dentate granule cells using competitive learning to convert grid-like entorhinal cortex firing to place-like fields, and in the dentate to CA3 connections that have diluted connectivity. Recall to the neocortex is achieved by a reverse hierarchical series of pattern association networks implemented by the hippocampo-cortical backprojections, each one of which performs some pattern generalization, to retrieve a complete pattern of cortical firing in higher-order cortical areas. New results on competitive networks show which factors contribute to their ability to perform pattern separation, pattern clustering, and pattern categorisation, and how these apply in different hippocampal and neocortical systems.
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Affiliation(s)
- Edmund T Rolls
- Oxford Centre for Computational Neuroscience, Oxford, England, United Kingdom; University of Warwick, Department of Computer Science, Coventry CV4 7AL, England, United Kingdom.
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41
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Hagmeyer S, Haderspeck JC, Grabrucker AM. Behavioral impairments in animal models for zinc deficiency. Front Behav Neurosci 2015; 8:443. [PMID: 25610379 PMCID: PMC4285094 DOI: 10.3389/fnbeh.2014.00443] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 12/08/2014] [Indexed: 01/12/2023] Open
Abstract
Apart from teratogenic and pathological effects of zinc deficiency such as the occurrence of skin lesions, anorexia, growth retardation, depressed wound healing, altered immune function, impaired night vision, and alterations in taste and smell acuity, characteristic behavioral changes in animal models and human patients suffering from zinc deficiency have been observed. Given that it is estimated that about 17% of the worldwide population are at risk for zinc deficiency and that zinc deficiency is associated with a variety of brain disorders and disease states in humans, it is of major interest to investigate, how these behavioral changes will affect the individual and a putative course of a disease. Thus, here, we provide a state of the art overview about the behavioral phenotypes observed in various models of zinc deficiency, among them environmentally produced zinc deficient animals as well as animal models based on a genetic alteration of a particular zinc homeostasis gene. Finally, we compare the behavioral phenotypes to the human condition of mild to severe zinc deficiency and provide a model, how zinc deficiency that is associated with many neurodegenerative and neuropsychological disorders might modify the disease pathologies.
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Affiliation(s)
- Simone Hagmeyer
- WG Molecular Analysis of Synaptopathies, Neurology Department, Neurocenter of Ulm University Ulm, Germany
| | - Jasmin Carmen Haderspeck
- WG Molecular Analysis of Synaptopathies, Neurology Department, Neurocenter of Ulm University Ulm, Germany
| | - Andreas Martin Grabrucker
- WG Molecular Analysis of Synaptopathies, Neurology Department, Neurocenter of Ulm University Ulm, Germany ; Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany
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42
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A computational theory of hippocampal function, and tests of the theory: New developments. Neurosci Biobehav Rev 2015; 48:92-147. [DOI: 10.1016/j.neubiorev.2014.11.009] [Citation(s) in RCA: 226] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 10/24/2014] [Accepted: 11/12/2014] [Indexed: 01/01/2023]
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Costa V, Lugert S, Jagasia R. Role of adult hippocampal neurogenesis in cognition in physiology and disease: pharmacological targets and biomarkers. Handb Exp Pharmacol 2015; 228:99-155. [PMID: 25977081 DOI: 10.1007/978-3-319-16522-6_4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adult hippocampal neurogenesis is a remarkable form of brain structural plasticity by which new functional neurons are generated from adult neural stem cells/precursors. Although the precise role of this process remains elusive, adult hippocampal neurogenesis is important for learning and memory and it is affected in disease conditions associated with cognitive impairment, depression, and anxiety. Immature neurons in the adult brain exhibit an enhanced structural and synaptic plasticity during their maturation representing a unique population of neurons to mediate specific hippocampal function. Compelling preclinical evidence suggests that hippocampal neurogenesis is modulated by a broad range of physiological stimuli which are relevant in cognitive and emotional states. Moreover, multiple pharmacological interventions targeting cognition modulate adult hippocampal neurogenesis. In addition, recent genetic approaches have shown that promoting neurogenesis can positively modulate cognition associated with both physiology and disease. Thus the discovery of signaling pathways that enhance adult neurogenesis may lead to therapeutic strategies for improving memory loss due to aging or disease. This chapter endeavors to review the literature in the field, with particular focus on (1) the role of hippocampal neurogenesis in cognition in physiology and disease; (2) extrinsic and intrinsic signals that modulate hippocampal neurogenesis with a focus on pharmacological targets; and (3) efforts toward novel strategies pharmacologically targeting neurogenesis and identification of biomarkers of human neurogenesis.
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Affiliation(s)
- Veronica Costa
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases (NORD), Roche Innovation Center Basel, 124 Grenzacherstrasse, 4070, Basel, Switzerland
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Ceccom J, Halley H, Daumas S, Lassalle JM. A specific role for hippocampal mossy fiber's zinc in rapid storage of emotional memories. Learn Mem 2014; 21:287-97. [PMID: 24741109 PMCID: PMC3994499 DOI: 10.1101/lm.033472.113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We investigated the specific role of zinc present in large amounts in the synaptic vesicles of mossy fibers and coreleased with glutamate in the CA3 region. In previous studies, we have shown that blockade of zinc after release has no effect on the consolidation of spatial learning, while zinc is required for the consolidation of contextual fear conditioning. Although both are hippocampo-dependent processes, fear conditioning to the context implies a strong emotional burden. To verify the hypothesis that zinc could play a specific role in enabling sustainable memorization of a single event with a strong emotional component, we used a neuropharmacological approach combining a glutamate receptor antagonist with different zinc chelators. Results show that zinc is mandatory to allow the consolidation of one-shot memory, thus being the key element allowing the hippocampus submitted to a strong emotional charge to switch from the cognitive mode to a flashbulb memory mode. Individual differences in learning abilities have been known for a long time to be totally or partially compensated by distributed learning practice. Here we show that contextual fear conditioning impairments due to zinc blockade can be efficiently reduced by distributed learning practice.
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Affiliation(s)
- Johnatan Ceccom
- Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, F-31062 Toulouse Cedex 9, France
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45
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Inoue N, Watanabe S. Effects of reversible deactivation of mossy fibers in the dentate-CA3 system on geometric center detection task in mice: Functional separation of spatial learning and its generalization to new environment. Physiol Behav 2014; 131:75-80. [PMID: 24732418 DOI: 10.1016/j.physbeh.2014.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 02/28/2014] [Accepted: 04/04/2014] [Indexed: 11/19/2022]
Abstract
Using diethyldithiocarbamate (DEDTC), a zinc chelator, we deactivated the mossy fibers that project from the dentate gyrus (DG) to the CA3 during acquisition and testing of a center detection task in mice. The mice were trained to find a food pellet at the center of four objects in a circular area. DEDTC injection just before the training sessions impaired this learning, whereas DEDTC injection before the probe test did not impair recall of the memory. DEDTC injection before a pattern completion test in which only one of the four objects was presented did not cause deficits in this test. DEDTC injection did, however, cause severe deficits in an array shift test in which all four objects were moved to new positions. These results demonstrated that 1) the DG-CA3 system plays a crucial role in the learning of geometric center detection task but not in its recall or pattern completion, and 2) the DG-CA3 system is involved in generalization to a new environment but is not crucial for pattern completion.
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Affiliation(s)
- Naomi Inoue
- Department of Psychology, Keio University, 2-2-24 Mita, Minato-ku, Tokyo 108-8345, Japan
| | - Shigeru Watanabe
- Department of Psychology, Keio University, 2-2-24 Mita, Minato-ku, Tokyo 108-8345, Japan.
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46
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Physical exercise-induced adult neurogenesis: a good strategy to prevent cognitive decline in neurodegenerative diseases? BIOMED RESEARCH INTERNATIONAL 2014; 2014:403120. [PMID: 24818140 PMCID: PMC4000963 DOI: 10.1155/2014/403120] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 02/16/2014] [Accepted: 02/16/2014] [Indexed: 01/19/2023]
Abstract
Cumulative evidence has indicated that there is an important role for adult hippocampal neurogenesis in cognitive function. With the increasing prevalence of cognitive decline associated with neurodegenerative diseases among the ageing population, physical exercise, a potent enhancer of adult hippocampal neurogenesis, has emerged as a potential preventative strategy/treatment to reduce cognitive decline. Here we review the functional role of adult hippocampal neurogenesis in learning and memory, and how this form of structural plasticity is altered in neurodegenerative diseases known to involve cognitive impairment. We further discuss how physical exercise may contribute to cognitive improvement in the ageing brain by preserving adult neurogenesis, and review the recent approaches for measuring changes in neurogenesis in the live human brain.
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47
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Chakravarthi KK, Avadhani R. Enhancement of Hippocampal CA3 Neuronal Dendritic Arborization by Glycyrrhiza glabra root extract Treatment in Wistar Albino Rats. J Nat Sci Biol Med 2014; 5:25-9. [PMID: 24678192 PMCID: PMC3961946 DOI: 10.4103/0976-9668.127279] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Background: In the traditional system of medicine, the roots and rhizomes of Glycyrrhiza glabra (Gg) (family: Leguminosae) have been in clinical use for centuries. Aim: In the present study, we investigated the role of aqueous extract of root of Gg treatment on the dendritic morphology of hippocampal Cornu Ammonis area three (CA3) neurons, one of the regions concerned with learning and memory, in 1- month- old male Wistar albino rats. Materials and Methods: The aqueous extract of root of Gg was administered orally in four doses (75, 150, 225 and 300 mg/kg) for 4 weeks. After the treatment period, all experimental animals were subjected to spatial learning (Morris water maze, Hebb-William's maze and elevated plus maze) tests. At the end of the spatial memory tests, the rats were deeply anesthetized with Pentobarbitone and killed their brains were removed rapidly and fixed in rapid Golgi fixative. Hippocampal CA3 neurons were traced using camera lucida, and dendritic arborization and intersections were quantified. These data were compared to those of age-matched control rats. Results: The aqueous root extract of Gg in the dose of 150 and 225 mg/kg/p.o showed a significant (P < 0.01) enhancement of dendritic arborization (dendritic branching points) and dendritic intersections along the length of both apical and basal dendrites in hippocampal (CA3) pyramidal neurons is comparable to control. Conclusion: Based on our results obtained, we conclude that constituents present in aqueous root extract of Gg have neuronal dendritic growth stimulating properties.
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Affiliation(s)
| | - Ramakrishna Avadhani
- Department of Anatomy, Yenepoya Medical College, Yenepoya University, Deralakatte, Mangalore, Karnataka, India
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48
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Rolls ET. The mechanisms for pattern completion and pattern separation in the hippocampus. Front Syst Neurosci 2013; 7:74. [PMID: 24198767 PMCID: PMC3812781 DOI: 10.3389/fnsys.2013.00074] [Citation(s) in RCA: 263] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 10/14/2013] [Indexed: 12/30/2022] Open
Abstract
The mechanisms for pattern completion and pattern separation are described in the context of a theory of hippocampal function in which the hippocampal CA3 system operates as a single attractor or autoassociation network to enable rapid, one-trial, associations between any spatial location (place in rodents, or spatial view in primates) and an object or reward, and to provide for completion of the whole memory during recall from any part. The factors important in the pattern completion in CA3 together with a large number of independent memories stored in CA3 include a sparse distributed representation which is enhanced by the graded firing rates of CA3 neurons, representations that are independent due to the randomizing effect of the mossy fibers, heterosynaptic long-term depression as well as long-term potentiation in the recurrent collateral synapses, and diluted connectivity to minimize the number of multiple synapses between any pair of CA3 neurons which otherwise distort the basins of attraction. Recall of information from CA3 is implemented by the entorhinal cortex perforant path synapses to CA3 cells, which in acting as a pattern associator allow some pattern generalization. Pattern separation is performed in the dentate granule cells using competitive learning to convert grid-like entorhinal cortex firing to place-like fields. Pattern separation in CA3, which is important for completion of any one of the stored patterns from a fragment, is provided for by the randomizing effect of the mossy fiber synapses to which neurogenesis may contribute, by the large number of dentate granule cells each with a sparse representation, and by the sparse independent representations in CA3. Recall to the neocortex is achieved by a reverse hierarchical series of pattern association networks implemented by the hippocampo-cortical backprojections, each one of which performs some pattern generalization, to retrieve a complete pattern of cortical firing in higher-order cortical areas.
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Affiliation(s)
- Edmund T. Rolls
- Oxford Centre for Computational NeuroscienceOxford, UK
- Department of Computer Science, University of WarwickCoventry, UK
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49
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Hippocampal neurogenesis levels predict WATERMAZE search strategies in the aging brain. PLoS One 2013; 8:e75125. [PMID: 24086453 PMCID: PMC3781090 DOI: 10.1371/journal.pone.0075125] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 08/07/2013] [Indexed: 12/12/2022] Open
Abstract
The hippocampus plays a crucial role in the formation of spatial memories, and it is thought that adult hippocampal neurogenesis may participate in this form of learning. To better elucidate the relationship between neurogenesis and spatial learning, we examined both across the entire life span of mice. We found that cell proliferation, neuronal differentiation, and neurogenesis significantly decrease with age, and that there is an abrupt reduction in these processes early on, between 1.5-3 months of age. After this, the neurogenic capacity continues to decline steadily. The initial abrupt decline in adult neurogenesis was paralleled by a significant reduction in Morris Water Maze performance, however overall learning and memory remained constant thereafter. Further analysis of the search strategies employed revealed that reductions in neurogenesis in the aging brain were strongly correlated with the adoption of spatially imprecise search strategies. Overall, performance measures of learning and memory in the Morris Water Maze were maintained at relatively constant levels in aging animals due to an increase in the use of spatially imprecise search strategies.
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50
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Gould TJ, Leach PT. Cellular, molecular, and genetic substrates underlying the impact of nicotine on learning. Neurobiol Learn Mem 2013; 107:108-32. [PMID: 23973448 DOI: 10.1016/j.nlm.2013.08.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 08/13/2013] [Accepted: 08/13/2013] [Indexed: 12/27/2022]
Abstract
Addiction is a chronic disorder marked by long-lasting maladaptive changes in behavior and in reward system function. However, the factors that contribute to the behavioral and biological changes that occur with addiction are complex and go beyond reward. Addiction involves changes in cognitive control and the development of disruptive drug-stimuli associations that can drive behavior. A reason for the strong influence drugs of abuse can exert on cognition may be the striking overlap between the neurobiological substrates of addiction and of learning and memory, especially areas involved in declarative memory. Declarative memories are critically involved in the formation of autobiographical memories, and the ability of drugs of abuse to alter these memories could be particularly detrimental. A key structure in this memory system is the hippocampus, which is critically involved in binding multimodal stimuli together to form complex long-term memories. While all drugs of abuse can alter hippocampal function, this review focuses on nicotine. Addiction to tobacco products is insidious, with the majority of smokers wanting to quit; yet the majority of those that attempt to quit fail. Nicotine addiction is associated with the presence of drug-context and drug-cue associations that trigger drug seeking behavior and altered cognition during periods of abstinence, which contributes to relapse. This suggests that understanding the effects of nicotine on learning and memory will advance understanding and potentially facilitate treating nicotine addiction. The following sections examine: (1) how the effects of nicotine on hippocampus-dependent learning change as nicotine administration transitions from acute to chronic and then to withdrawal from chronic treatment and the potential impact of these changes on addiction, (2) how nicotine usurps the cellular mechanisms of synaptic plasticity, (3) the physiological changes in the hippocampus that may contribute to nicotine withdrawal deficits in learning, and (4) the role of genetics and developmental stage (i.e., adolescence) in these effects.
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Affiliation(s)
- Thomas J Gould
- Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States.
| | - Prescott T Leach
- Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
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