1
|
Mercier MS, Magloire V, Cornford JH, Kullmann DM. Long-term potentiation in neurogliaform interneurons modulates excitation-inhibition balance in the temporoammonic pathway. J Physiol 2022; 600:4001-4017. [PMID: 35876215 PMCID: PMC9540908 DOI: 10.1113/jp282753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/19/2022] [Indexed: 11/08/2022] Open
Abstract
Apical dendrites of pyramidal neurons integrate information from higher-order cortex and thalamus, and gate signalling and plasticity at proximal synapses. In the hippocampus, neurogliaform cells and other interneurons located within stratum lacunosum-moleculare (SLM) mediate powerful inhibition of CA1 pyramidal neuron distal dendrites. Is the recruitment of such inhibition itself subject to use-dependent plasticity, and if so, what induction rules apply? Here we show that interneurons in mouse SLM exhibit Hebbian NMDA receptor-dependent long-term potentiation (LTP). Such plasticity can be induced by selective optogenetic stimulation of afferents in the temporoammonic pathway from the entorhinal cortex (EC), but not by equivalent stimulation of afferents from the thalamic nucleus reuniens. We further show that theta-burst patterns of afferent firing induces LTP in neurogliaform interneurons identified using neuron-derived neurotrophic factor (Ndnf)-Cre mice. Theta-burst activity of EC afferents led to an increase in disynaptic feed-forward inhibition, but not monosynaptic excitation, of CA1 pyramidal neurons. Activity-dependent synaptic plasticity in SLM interneurons thus alters the excitation-inhibition balance at EC inputs to the apical dendrites of pyramidal neurons, implying a dynamic role for these interneurons in gating CA1 dendritic computations. KEY POINTS: Electrogenic phenomena in distal dendrites of principal neurons in the hippocampus have a major role in gating synaptic plasticity at afferent synapses on proximal dendrites. Apical dendrites also receive powerful feed-forward inhibition, mediated in large part by neurogliaform neurons. Here we show that theta-burst activity in afferents from the entorhinal cortex (EC) induces 'Hebbian' long-term potentiation (LTP) at excitatory synapses recruiting these GABAergic cells. LTP in interneurons innervating apical dendrites increases disynaptic inhibition of principal neurons, thus shifting the excitation-inhibition balance in the temporoammonic (TA) pathway in favour of inhibition, with implications for computations and learning rules in proximal dendrites.
Collapse
Affiliation(s)
- Marion S. Mercier
- UCL Queen Square Institute of NeurologyDepartment of Clinical and Experimental EpilepsyUniversity College LondonLondonUK
| | - Vincent Magloire
- UCL Queen Square Institute of NeurologyDepartment of Clinical and Experimental EpilepsyUniversity College LondonLondonUK
| | - Jonathan H. Cornford
- UCL Queen Square Institute of NeurologyDepartment of Clinical and Experimental EpilepsyUniversity College LondonLondonUK
| | - Dimitri M. Kullmann
- UCL Queen Square Institute of NeurologyDepartment of Clinical and Experimental EpilepsyUniversity College LondonLondonUK
| |
Collapse
|
2
|
Barranco A, Garcia L, Gruart A, Delgado-Garcia JM, Rueda R, Ramirez M. Effects of β-Hydroxy β-Methylbutyrate Supplementation on Working Memory and Hippocampal Long-Term Potentiation in Rodents. Nutrients 2022; 14:nu14051090. [PMID: 35268065 PMCID: PMC8912805 DOI: 10.3390/nu14051090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 02/05/2023] Open
Abstract
β-hydroxy β-methylbutyrate (HMB), a metabolite of the essential amino acid leucine, has been shown to preserve muscle mass and strength during aging. The signaling mechanism by which HMB elicits its favorable effects on protein metabolism in skeletal muscle is also preserved in the brain. However, there are only a few studies, all at relatively high doses, addressing the effect of HMB supplementation on cognition. This study evaluated the effects of different doses of HMB on the potentiation of hippocampal synapses following the experimental induction of long-term potentiation (LTP) in the hippocampus of behaving rats, as well as on working memory test (delayed matching-to-position, DMTP) in mice. HMB doses in rats were 225 (low), 450 (medium), and 900 (high) mg/kg body weight/day and were double in mice. Rats who received medium or high HMB doses improved LTP, suggesting that HMB administration enhances mechanisms related to neuronal plasticity. In the DMTP test, mice that received any of the tested doses of HMB performed better than the control group in the overall test with particularities depending on the dose and the task phase.
Collapse
Affiliation(s)
- Alejandro Barranco
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, 18071 Granada, Spain;
| | | | - Agnes Gruart
- Division of Neurosciences, Pablo de Olavide University, 41001 Seville, Spain; (A.G.); (J.M.D.-G.)
| | | | - Ricardo Rueda
- Abbott Nutrition, Research and Development, 18004 Granada, Spain;
| | - Maria Ramirez
- Abbott Nutrition, Research and Development, 18004 Granada, Spain;
- Correspondence: ; Tel.: +34-669-127998
| |
Collapse
|
3
|
Romero-Barragán MT, Gruart A, Delgado-García JM. Transsynaptic Long-Term Potentiation in the Hippocampus of Behaving Mice. Front Synaptic Neurosci 2022; 13:811806. [PMID: 35126083 PMCID: PMC8810508 DOI: 10.3389/fnsyn.2021.811806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/31/2021] [Indexed: 11/17/2022] Open
Abstract
Long-term potentiation (LTP) is an experimental procedure that shares certain mechanisms with neuronal learning and memory processes and represents a well-known example of synaptic plasticity. LTP consists of an increase of the synaptic response to a control stimulus following the presentation of a high-frequency stimulation (HFS) train to an afferent pathway. This technique is studied mostly in the hippocampus due to the latter’s high susceptibility and its laminar nature which facilitates the location of defined synapses. Although most preceding studies have been performed in vitro, we have developed an experimental approach to carry out these experiments in alert behaving animals. The main goal of this study was to confirm the existence of synaptic changes in strength in synapses that are post-synaptic to the one presented with the HFS. We recorded field excitatory post-synaptic potentials (fEPSPs) evoked in five hippocampal synapses, from both hemispheres, of adult male mice. HFS was presented to the perforant pathway (PP). We characterized input/output curves, paired-pulse stimulation, and LTP of these synapses. We also performed depth-profile recordings to determine differences in fEPSP latencies. Collected data indicate that the five selected synapses have similar basic electrophysiological properties, a fact that enables an easier comparison of LTP characteristics. Importantly, we observed the presence of significant LTP in the contralateral CA1 (cCA1) area following the control stimulation of non-HFS-activated pathways. These results indicate that LTP appears as a physiological process present in synapses located far away from the HFS-stimulated afferent pathway.
Collapse
|
4
|
Stojanovic T, Velarde Gamez D, Schuld GJ, Bormann D, Cabatic M, Uhrin P, Lubec G, Monje FJ. Age-Dependent and Pathway-Specific Bimodal Action of Nicotine on Synaptic Plasticity in the Hippocampus of Mice Lacking the miR-132/212 Genes. Cells 2022; 11:261. [PMID: 35053378 PMCID: PMC8774101 DOI: 10.3390/cells11020261] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/06/2022] [Accepted: 01/11/2022] [Indexed: 12/19/2022] Open
Abstract
Nicotine addiction develops predominantly during human adolescence through smoking. Self-administration experiments in rodents verify this biological preponderance to adolescence, suggesting evolutionary-conserved and age-defined mechanisms which influence the susceptibility to nicotine addiction. The hippocampus, a brain region linked to drug-related memory storage, undergoes major morpho-functional restructuring during adolescence and is strongly affected by nicotine stimulation. However, the signaling mechanisms shaping the effects of nicotine in young vs. adult brains remain unclear. MicroRNAs (miRNAs) emerged recently as modulators of brain neuroplasticity, learning and memory, and addiction. Nevertheless, the age-dependent interplay between miRNAs regulation and hippocampal nicotinergic signaling remains poorly explored. We here combined biophysical and pharmacological methods to examine the impact of miRNA-132/212 gene-deletion (miRNA-132/212-/-) and nicotine stimulation on synaptic functions in adolescent and mature adult mice at two hippocampal synaptic circuits: the medial perforant pathway (MPP) to dentate yrus (DG) synapses (MPP-DG) and CA3 Schaffer collaterals to CA1 synapses (CA3-CA1). Basal synaptic transmission and short-term (paired-pulse-induced) synaptic plasticity was unaltered in adolescent and adult miRNA-132/212-/- mice hippocampi, compared with wild-type controls. However, nicotine stimulation promoted CA3-CA1 synaptic potentiation in mature adult (not adolescent) wild-type and suppressed MPP-DG synaptic potentiation in miRNA-132/212-/- mice. Altered levels of CREB, Phospho-CREB, and acetylcholinesterase (AChE) expression were further detected in adult miRNA-132/212-/- mice hippocampi. These observations propose miRNAs as age-sensitive bimodal regulators of hippocampal nicotinergic signaling and, given the relevance of the hippocampus for drug-related memory storage, encourage further research on the influence of miRNAs 132 and 212 in nicotine addiction in the young and the adult brain.
Collapse
Affiliation(s)
- Tamara Stojanovic
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria; (D.V.G.); (G.J.S.); (D.B.); (M.C.)
| | - David Velarde Gamez
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria; (D.V.G.); (G.J.S.); (D.B.); (M.C.)
| | - Gabor Jorrid Schuld
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria; (D.V.G.); (G.J.S.); (D.B.); (M.C.)
| | - Daniel Bormann
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria; (D.V.G.); (G.J.S.); (D.B.); (M.C.)
- Laboratory for Cardiac and Thoracic Diagnosis, Department of Surgery, Regeneration and Applied Immunology, Medical University of Vienna, Research Laboratories Vienna General Hospital, Waehringer Guertel 18-20, 1090 Vienna, Austria
- Division of Thoracic Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Maureen Cabatic
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria; (D.V.G.); (G.J.S.); (D.B.); (M.C.)
| | - Pavel Uhrin
- Center for Physiology and Pharmacology, Department of Vascular Biology and Thrombosis Research, Medical University of Vienna, 1090 Vienna, Austria;
| | - Gert Lubec
- Department of Neuroproteomics, Paracelsus Medical University, 5020 Salzburg, Austria;
| | - Francisco J. Monje
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria; (D.V.G.); (G.J.S.); (D.B.); (M.C.)
| |
Collapse
|
5
|
Li RR, Yan J, Chen H, Zhang WW, Hu YB, Zhang J, Hu ZA, Xiong Y, Yao ZX, Hu B. Sleep Deprivation Impairs Learning-Induced Increase in Hippocampal Sharp Wave Ripples and Associated Spike Dynamics during Recovery Sleep. Cereb Cortex 2021; 32:824-838. [PMID: 34383018 DOI: 10.1093/cercor/bhab247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 11/14/2022] Open
Abstract
Sleep deprivation (SD) causes deficits in off-line memory consolidation, but the underlying network oscillation mechanisms remain unclear. Hippocampal sharp wave ripple (SWR) oscillations play a critical role in off-line memory consolidation. Therefore, we trained mice to learn a hippocampus-dependent trace eyeblink conditioning (tEBC) task and explored the influence of 1.5-h postlearning SD on hippocampal SWRs and related spike dynamics during recovery sleep. We found an increase in hippocampal SWRs during postlearning sleep, which predicted the consolidation of tEBC in conditioned mice. In contrast, sleep-deprived mice showed a loss of tEBC learning-induced increase in hippocampal SWRs during recovery sleep. Moreover, the sleep-deprived mice exhibited weaker reactivation of tEBC learning-associated pyramidal cells in hippocampal SWRs during recovery sleep. In line with these findings, tEBC consolidation was impaired in sleep-deprived mice. Furthermore, sleep-deprived mice showed augmented fast excitation from pyramidal cells to interneurons and enhanced participation of interneurons in hippocampal SWRs during recovery sleep. Among various interneurons, parvalbumin-expressing interneurons specifically exhibited overexcitation during hippocampal SWRs. Our findings suggest that altered hippocampal SWRs and associated spike dynamics during recovery sleep may be candidate network oscillation mechanisms underlying SD-induced memory deficits.
Collapse
Affiliation(s)
- Rong-Rong Li
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jie Yan
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Hao Chen
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Wei-Wei Zhang
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Yu-Bo Hu
- Department of Orthopaedics, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Jie Zhang
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Zhi-An Hu
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Yan Xiong
- Department of Orthopaedics, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Zhong-Xiang Yao
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Bo Hu
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China.,Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Army Medical University, Chongqing 400038, China
| |
Collapse
|
6
|
Missaire M, Fraize N, Comte JC, Truchet B, Parmentier R, Salin PA, Malleret G. Working and Reference Memory Tasks Trigger Opposed Long-Term Synaptic Changes in the Rat Dentate Gyrus. Cereb Cortex 2021; 31:2980-2992. [PMID: 33506269 DOI: 10.1093/cercor/bhaa405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 12/16/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Long-term storage of information into memory is supposed to rely on long-term synaptic plasticity processes. The detection of such synaptic changes after training in long-term/reference memory (RM) tasks has yet been scarce, variable and only studied on a short time scale. Short-term or working memory (WM) is largely known to depend on persistent neuronal activity or short-term plasticity. However, processing information into WM could also involve long-term synaptic changes that could be responsible for the erasure/forgetting of items previously stored in WM and acting as proactive interference. In order to study long-term synaptic changes associated with RM or WM, we trained chronically implanted rats in 3 different radial maze tasks: a classical RM task and 2 WM tasks involving different levels of proactive interference. Synaptic responses in the dentate gyrus were recorded during 2 × 24 h in freely moving rats after training. We found that consolidation of long-term information leads first to a delayed synaptic potentiation, occurring 9 h after RM training that is replaced by a synaptic depression once the RM rule is fully acquired. In contrast, optimal information processing into WM triggers a synaptic depression immediately after training and lasting 3 h that could act as a mechanism for interference erasure/forgetting.
Collapse
Affiliation(s)
- Mégane Missaire
- FORGETTING 'Forgetting Processes and Cortical Dynamics' Team, Lyon Neuroscience Research Center (CRNL), University Lyon 1, Lyon F-69008, France
| | - Nicolas Fraize
- FORGETTING 'Forgetting Processes and Cortical Dynamics' Team, Lyon Neuroscience Research Center (CRNL), University Lyon 1, Lyon F-69008, France
| | - Jean-Christophe Comte
- FORGETTING 'Forgetting Processes and Cortical Dynamics' Team, Lyon Neuroscience Research Center (CRNL), University Lyon 1, Lyon F-69008, France.,Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Lyon F-69000, France
| | - Bruno Truchet
- Laboratory of Cognitive Neuroscience, CNRS and Aix-Marseille University, Marseille F-13331, France
| | - Régis Parmentier
- FORGETTING 'Forgetting Processes and Cortical Dynamics' Team, Lyon Neuroscience Research Center (CRNL), University Lyon 1, Lyon F-69008, France.,Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Lyon F-69000, France
| | - Paul-Antoine Salin
- FORGETTING 'Forgetting Processes and Cortical Dynamics' Team, Lyon Neuroscience Research Center (CRNL), University Lyon 1, Lyon F-69008, France.,Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Lyon F-69000, France
| | - Gaël Malleret
- FORGETTING 'Forgetting Processes and Cortical Dynamics' Team, Lyon Neuroscience Research Center (CRNL), University Lyon 1, Lyon F-69008, France.,Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Lyon F-69000, France
| |
Collapse
|
7
|
Blazquez-Llorca L, Miguéns M, Montero-Crespo M, Selvas A, Gonzalez-Soriano J, Ambrosio E, DeFelipe J. 3D Synaptic Organization of the Rat CA1 and Alterations Induced by Cocaine Self-Administration. Cereb Cortex 2021; 31:1927-1952. [PMID: 33253368 PMCID: PMC7945021 DOI: 10.1093/cercor/bhaa331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/10/2020] [Accepted: 10/12/2020] [Indexed: 12/24/2022] Open
Abstract
The hippocampus plays a key role in contextual conditioning and has been proposed as an important component of the cocaine addiction brain circuit. To gain knowledge about cocaine-induced alterations in this circuit, we used focused ion beam milling/scanning electron microscopy to reveal and quantify the three-dimensional synaptic organization of the neuropil of the stratum radiatum of the rat CA1, under normal circumstances and after cocaine-self administration (SA). Most synapses are asymmetric (excitatory), macular-shaped, and in contact with dendritic spine heads. After cocaine-SA, the size and the complexity of the shape of both asymmetric and symmetric (inhibitory) synapses increased but no changes were observed in the synaptic density. This work constitutes the first detailed report on the 3D synaptic organization in the stratum radiatum of the CA1 field of cocaine-SA rats. Our data contribute to the elucidation of the normal and altered synaptic organization of the hippocampus, which is crucial for better understanding the neurobiological mechanisms underlying cocaine addiction.
Collapse
Affiliation(s)
- L Blazquez-Llorca
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain.,Sección Departamental de Anatomía y Embriología (Veterinaria), Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - M Miguéns
- Departamento de Psicología Básica I, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - M Montero-Crespo
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - A Selvas
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - J Gonzalez-Soriano
- Sección Departamental de Anatomía y Embriología (Veterinaria), Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - E Ambrosio
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain
| | - J DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| |
Collapse
|
8
|
Espadas I, Ortiz O, García-Sanz P, Sanz-Magro A, Alberquilla S, Solis O, Delgado-García JM, Gruart A, Moratalla R. Dopamine D2R is Required for Hippocampal-dependent Memory and Plasticity at the CA3-CA1 Synapse. Cereb Cortex 2021; 31:2187-2204. [PMID: 33264389 PMCID: PMC7945019 DOI: 10.1093/cercor/bhaa354] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/04/2020] [Accepted: 10/23/2020] [Indexed: 12/24/2022] Open
Abstract
Dopamine receptors play an important role in motivational, emotional, and motor responses. In addition, growing evidence suggests a key role of hippocampal dopamine receptors in learning and memory. It is well known that associative learning and synaptic plasticity of CA3-CA1 requires the dopamine D1 receptor (D1R). However, the specific role of the dopamine D2 receptor (D2R) on memory-related neuroplasticity processes is still undefined. Here, by using two models of D2R loss, D2R knockout mice (Drd2-/-) and mice with intrahippocampal injections of Drd2-small interfering RNA (Drd2-siRNA), we aimed to investigate how D2R is involved in learning and memory as well as in long-term potentiation of the hippocampus. Our studies revealed that the genetic inactivation of D2R impaired the spatial memory, associative learning, and the classical conditioning of eyelid responses. Similarly, deletion of D2R reduced the activity-dependent synaptic plasticity in the hippocampal CA1-CA3 synapse. Our results demonstrate the first direct evidence that D2R is essential in behaving mice for trace eye blink conditioning and associated changes in hippocampal synaptic strength. Taken together, these results indicate a key role of D2R in regulating hippocampal plasticity changes and, in consequence, acquisition and consolidation of spatial and associative forms of memory.
Collapse
Affiliation(s)
- Isabel Espadas
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Oscar Ortiz
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Patricia García-Sanz
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Adrián Sanz-Magro
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Samuel Alberquilla
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Oscar Solis
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | | | - Agnès Gruart
- División de Neurociencias, Univ. Pablo de Olavide, Sevilla 41013, Spain
| | - Rosario Moratalla
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| |
Collapse
|
9
|
Stojanovic T, Benes H, Awad A, Bormann D, Monje FJ. Nicotine abolishes memory-related synaptic strengthening and promotes synaptic depression in the neurogenic dentate gyrus of miR-132/212 knockout mice. Addict Biol 2021; 26:e12905. [PMID: 32293776 PMCID: PMC7988623 DOI: 10.1111/adb.12905] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/21/2020] [Accepted: 03/30/2020] [Indexed: 12/25/2022]
Abstract
Micro-RNAs (miRNAs) are highly evolutionarily conserved short-length/noncoding RNA molecules that modulate a wide range of cellular functions in many cell types by regulating the expression of a variety of targeted genes. miRNAs have also recently emerged as key regulators of neuronal genes mediating the effects of psychostimulant drugs and memory-related neuroplasticity processes. Smoking is a predominant addictive behaviour associated with millions of deaths worldwide, and nicotine is a potent natural psychoactive agonist of cholinergic receptors, highly abundant in cigarettes. The influence of miRNAs modulation on cholinergic signalling in the nervous system remains however poorly explored. Using miRNA knockout mice and biochemical, electrophysiological and pharmacological approaches, we examined the effects of miR-132/212 gene disruption on the levels of hippocampal nicotinic acetylcholine receptors, total ERK and phosphorylated ERK (pERK) and MeCP2 protein levels, and studied the impact of nicotine stimulation on hippocampal synaptic transmission and synaptic depression and strengthening. miR-132/212 deletion significantly altered α7-nAChR and pERK protein levels, but not total ERK or MeCP2, and resulted in both exacerbated synaptic depression and virtually abolished memory-related synaptic strengthening upon nicotine stimulation. These observations reveal a functional miRNAs/nicotinergic signalling interplay critical for nicotinic-receptor expression and neuroplasticity in brain structures relevant for drug addiction and learning and memory functions.
Collapse
Affiliation(s)
- Tamara Stojanovic
- Center for Physiology and Pharmacology, Department of Neurophysiology and NeuropharmacologyMedical University of ViennaViennaAustria
| | - Hannah Benes
- Center for Physiology and Pharmacology, Department of Neurophysiology and NeuropharmacologyMedical University of ViennaViennaAustria
| | - Amena Awad
- Center for Physiology and Pharmacology, Department of Neurophysiology and NeuropharmacologyMedical University of ViennaViennaAustria
| | - Daniel Bormann
- Center for Physiology and Pharmacology, Department of Neurophysiology and NeuropharmacologyMedical University of ViennaViennaAustria
| | - Francisco J. Monje
- Center for Physiology and Pharmacology, Department of Neurophysiology and NeuropharmacologyMedical University of ViennaViennaAustria
| |
Collapse
|
10
|
Saneyoshi T. Reciprocal activation within a kinase effector complex: A mechanism for the persistence of molecular memory. Brain Res Bull 2021; 170:58-64. [PMID: 33556559 DOI: 10.1016/j.brainresbull.2021.01.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/10/2021] [Accepted: 01/25/2021] [Indexed: 01/01/2023]
Abstract
Synaptic connections in neuronal circuits change in response to neuronal activity patterns. This can induce a persistent change in the efficacy of synaptic transmission, a phenomenon known as synaptic plasticity. One form of plasticity, long-term potentiation (LTP) has been extensively studied as the cellular basis of memory. In LTP, the potentiated synaptic transmission persists along with structural changes in the synapses. Many studies have sought to identify the "memory molecule" or the "molecular engram". Ca2+/calmodulin-dependent protein kinase II (CaMKII) is probably the most well-studied candidate for the memory molecule. However, consensus has not yet been reached on a very basic aspect: how CaMKII is regulated during LTP. Here, I propose a new model of CaMKII regulation: reciprocal activation within a kinase effector complex (RAKEC) that is made between CaMKII and its effector protein, which is mediated by a persistent interaction between CaMKII and a pseudosubstrate sequence on T-lymphoma invasion and metastasis protein 1 (Tiam1), resulting in reciprocal activation of these two molecules. Through the RAKEC mechanism, CaMKII can maintain memory as biochemical activity in a synapse-specific manner. In this review, the detailed mechanism of the RAKEC and its expansion for the maintenance of LTP is described.
Collapse
Affiliation(s)
- Takeo Saneyoshi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
| |
Collapse
|
11
|
Martínez-Moreno CG, Arámburo C. Growth hormone (GH) and synaptogenesis. VITAMINS AND HORMONES 2020; 114:91-123. [PMID: 32723552 DOI: 10.1016/bs.vh.2020.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Growth hormone (GH) is known to exert several roles during development and function of the nervous system. Initially, GH was exclusively considered a pituitary hormone that regulates body growth and metabolism, but now its alternative extrapituitary production and pleiotropic functions are widely accepted. Through excess and deficit models, the critical role of GH in nervous system development and adult brain function has been extensively demonstrated. Moreover, neurotrophic actions of GH in neural tissues include pro-survival effects, neuroprotection, axonal growth, synaptogenesis, neurogenesis and neuroregeneration. The positive effects of GH upon memory, behavior, mood, sensorimotor function and quality of life, clearly implicate a beneficial action in synaptic physiology. Experimental and clinical evidence about GH actions in synaptic function modulation, protection and restoration are revised in this chapter.
Collapse
Affiliation(s)
- Carlos G Martínez-Moreno
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México
| | - Carlos Arámburo
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México.
| |
Collapse
|
12
|
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.
Collapse
|
13
|
Wu GY, Liu SL, Yao J, Li X, Wu B, Ye JN, Sui JF. Optogenetic Inhibition of Medial Prefrontal Cortex-Pontine Nuclei Projections During the Stimulus-free Trace Interval Impairs Temporal Associative Motor Learning. Cereb Cortex 2019; 28:3753-3763. [PMID: 28968654 DOI: 10.1093/cercor/bhx238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Indexed: 11/13/2022] Open
Abstract
The medial prefrontal cortex (mPFC) is closely involved in many higher-order cognitive functions, including learning to associate temporally discontiguous events (called temporal associative learning). However, direct evidence for the role of mPFC and the neural pathway underlying modulation of temporal associative motor learning is sparse. Here, we show that optogenetic inhibition of the mPFC or its axon terminals at the pontine nuclei (PN) during trace intervals or whole trial period significantly impaired the trace eyeblink conditioning (TEC), but had no significant effects on TEC during the conditioned stimulus or intertrial interval period. Our results suggest that activities associated with the mPFC-PN projection during trace intervals is crucial for trace associative motor learning. This finding is of great importance in understanding the mechanisms and the relevant neural pathways underlying mPFC modulation of temporal associative motor learning.
Collapse
Affiliation(s)
- Guang-Yan Wu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Shu-Lei Liu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Jian-Ning Ye
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jian-Feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| |
Collapse
|
14
|
Wu GY, Liu SL, Yao J, Sun L, Wu B, Yang Y, Li X, Sun QQ, Feng H, Sui JF. Medial Prefrontal Cortex-Pontine Nuclei Projections Modulate Suboptimal Cue-Induced Associative Motor Learning. Cereb Cortex 2019; 28:880-893. [PMID: 28077515 DOI: 10.1093/cercor/bhw410] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Indexed: 11/14/2022] Open
Abstract
Diverse and powerful mechanisms have evolved to enable organisms to modulate learning and memory under a variety of survival conditions. Cumulative evidence has shown that the prefrontal cortex (PFC) is closely involved in many higher-order cognitive functions. However, when and how the medial PFC (mPFC) modulates associative motor learning remains largely unknown. Here, we show that delay eyeblink conditioning (DEC) with the weak conditioned stimulus (wCS) but not the strong CS (sCS) elicited a significant increase in the levels of c-Fos expression in caudal mPFC. Both optogenetic inhibition and activation of the bilateral caudal mPFC, or its axon terminals at the pontine nucleus (PN) contralateral to the training eye, significantly impaired the acquisition, recent and remote retrieval of DEC with the wCS but not the sCS. However, direct optogenetic activation of the contralateral PN had no significant effect on the acquisition, recent and remote retrieval of DEC. These results are of great importance in understanding the elusive role of the mPFC and its projection to PN in subserving the associative motor learning under suboptimal learning cue.
Collapse
Affiliation(s)
- Guang-Yan Wu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Shu-Lei Liu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Lin Sun
- Institute of Physical Education, Southwest University, Chongqing400715, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Yi Yang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Jian-Feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| |
Collapse
|
15
|
Fernández-Lamo I, Delgado-García JM, Gruart A. When and Where Learning is Taking Place: Multisynaptic Changes in Strength During Different Behaviors Related to the Acquisition of an Operant Conditioning Task by Behaving Rats. Cereb Cortex 2019; 28:1011-1023. [PMID: 28199479 DOI: 10.1093/cercor/bhx011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Indexed: 01/02/2023] Open
Abstract
Although it is generally assumed that brain circuits are modified by new experiences, the question of which changes in synaptic efficacy take place in cortical and subcortical circuits across the learning process remains unanswered. Rats were trained in the acquisition of an operant conditioning in a Skinner box provided with light beams to detect animals' approaches to lever and feeder. Behaviors such as pressing the lever, eating, exploring, and grooming were also recorded. Animals were chronically implanted with stimulating and recording electrodes in hippocampal, prefrontal, and subcortical sites relevant to the task. Field synaptic potentials were evoked during the performance of the above-mentioned behaviors and before, during, and after the acquisition process. Afferent pathways to the hippocampus and the intrinsic hippocampal circuit were slightly modified in synaptic strength during the performance of those behaviors. In contrast, afferent and efferent circuits of the medial prefrontal cortex were significantly modified in synaptic strength across training sessions, mostly at the moment of the largest change in the learning curve. Performance of behaviors nondirectly related to the acquisition process (exploring, grooming) also evoked changes in synaptic strength across training. This study helps to understand when and where learning is being engraved in the brain.
Collapse
Affiliation(s)
- Iván Fernández-Lamo
- Division of Neurosciences, Pablo de Olavide University, 41013 Seville, Spain
| | | | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, 41013 Seville, Spain
| |
Collapse
|
16
|
Zhou H, Neville KR, Goldstein N, Kabu S, Kausar N, Ye R, Nguyen TT, Gelwan N, Hyman BT, Gomperts SN. Cholinergic modulation of hippocampal calcium activity across the sleep-wake cycle. eLife 2019; 8:39777. [PMID: 30843520 PMCID: PMC6435325 DOI: 10.7554/elife.39777] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 02/15/2019] [Indexed: 12/29/2022] Open
Abstract
Calcium is a critical second messenger in neurons that contributes to learning and memory, but how the coordination of action potentials of neuronal ensembles with the hippocampal local field potential (LFP) is reflected in dynamic calcium activity remains unclear. Here, we recorded hippocampal calcium activity with endoscopic imaging of the genetically encoded fluorophore GCaMP6 with concomitant LFP in freely behaving mice. Dynamic calcium activity was greater in exploratory behavior and REM sleep than in quiet wakefulness and slow wave sleep, behavioral states that differ with respect to theta and septal cholinergic activity, and modulated at sharp wave ripples (SWRs). Chemogenetic activation of septal cholinergic neurons expressing the excitatory hM3Dq DREADD increased calcium activity and reduced SWRs. Furthermore, inhibition of muscarinic acetylcholine receptors (mAChRs) reduced calcium activity while increasing SWRs. These results demonstrate that hippocampal dynamic calcium activity depends on behavioral and theta state as well as endogenous mAChR activation.
Collapse
Affiliation(s)
- Heng Zhou
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Kevin R Neville
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Nitsan Goldstein
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Shushi Kabu
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Naila Kausar
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Rong Ye
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Thuan Tinh Nguyen
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Noah Gelwan
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Bradley T Hyman
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| | - Stephen N Gomperts
- MasGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, United States
| |
Collapse
|
17
|
Maltsev AV, Bal NV, Balaban PM. LTP suppression by protein synthesis inhibitors is NO-dependent. Neuropharmacology 2018; 146:276-288. [PMID: 30540927 DOI: 10.1016/j.neuropharm.2018.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 11/19/2018] [Accepted: 12/08/2018] [Indexed: 01/25/2023]
Abstract
For several decades, the ability of protein synthesis inhibitors (PSI) to suppress the long-term potentiation (LTP) of hippocampal responses is known. It is considered that mechanisms of such impairment are related to a cessation of translation and a delayed depletion of the protein pool required for maintenance of synaptic plasticity. The present study demonstrates that cycloheximide or anisomycin applications reduce amplitudes of the field excitatory postsynaptic potentials as well as the presynaptically mediated form of plasticity, the paired-pulse facilitation after LTP induction in neurons of the CA1 area of hippocampus. We showed that nitric oxide signaling could be one of the pathways that cause the LTP decrease induced by cycloheximide or anisomycin. Inhibitor of the NO synthase, L-NNA or the NO scavenger, PTIO, rescued the late-phase LTP and restored the paired-pulse facilitation up to the control levels. For the first time we have directly measured the nitric oxide production induced by application of the translation blockers in hippocampal neurons using the NO-sensitive dye DAF-FM. Inhibitory analysis demonstrated that changes during protein synthesis blockade downstream the NO signaling cascade are cGMP-independent and apparently are implemented through degradation of target proteins. Prolonged application of the NO donor SNAP impaired the LTP maintenance in the same manner as PSI.
Collapse
Affiliation(s)
- Alexander V Maltsev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerovа 5A, 117485, Moscow, Russia
| | - Natalia V Bal
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerovа 5A, 117485, Moscow, Russia.
| | - Pavel M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerovа 5A, 117485, Moscow, Russia
| |
Collapse
|
18
|
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]
|
19
|
Delgado-García JM, Gruart A. Learning as a Functional State of the Brain: Studies in Wild-Type and Transgenic Animals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1015:75-93. [PMID: 29080022 DOI: 10.1007/978-3-319-62817-2_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Contemporary neuroscientists are paying increasing attention to subcellular, molecular, and electrophysiological mechanisms underlying learning and memory processes. Recent studies have examined the development of transgenic mice affected at different stages of the learning process, or have emulated in animals various human pathological conditions involving cognition and motor learning. However, a parallel effort is needed to develop stimulating and recording techniques suitable for use in behaving mice in order to understand activity-dependent synaptic changes taking place during the very moment of the learning process. The in vivo models should incorporate information collected from different molecular and in vitro approaches. Long-term potentiation (LTP) has been proposed as the neural mechanism underlying synaptic plasticity, and NMDA receptors have been proposed as the molecular substrate of LTP. It now seems necessary to study the relationship of both LTP and NMDA receptors to functional changes in synaptic efficiency taking place during actual learning in selected cerebral cortical structures. Here, we review data collected in our laboratory during the past 10 years on the involvement of different hippocampal synapses in the acquisition of the classically conditioned eyelid responses in behaving mice. Overall the results indicate a specific contribution of each cortical synapse to the acquisition and storage of new motor and cognitive abilities. Available data show that LTP, evoked by high-frequency stimulation of Schaffer collaterals, disturbs both the acquisition of conditioned eyelid responses and the physiological changes that occur at hippocampal synapses during learning. Moreover, the administration of NMDA-receptor antagonists is able not only to prevent LTP induction in vivo, but also to hinder both the formation of conditioned eyelid responses and functional changes in the strength of the CA3-CA1 synapse. Nevertheless, many other neurotransmitter receptors, intracellular mediators, and transcription factors are also involved in learning and memory processes. In summary, it can be proposed that learning and memory in behaving mammals are the result of the activation of complex and distributed functional states involving many different cerebral cortical synapses, with the participation also of various neurotransmitter systems.
Collapse
Affiliation(s)
- José M Delgado-García
- Division of Neurosciences, Pablo de Olavide University, Ctra. de Utrera, Km. 1, Seville, 41013, Spain.
| | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, Ctra. de Utrera, Km. 1, Seville, 41013, Spain
| |
Collapse
|
20
|
Fernández-Lamo I, Sánchez-Campusano R, Gruart A, Delgado-García M JM. Functional states of rat cortical circuits during the unpredictable availability of a reward-related cue. Sci Rep 2016; 6:37650. [PMID: 27869181 PMCID: PMC5116647 DOI: 10.1038/srep37650] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 10/28/2016] [Indexed: 12/23/2022] Open
Abstract
Proper performance of acquired abilities can be disturbed by the unexpected occurrence of external changes. Rats trained with an operant conditioning task (to press a lever in order to obtain a food pellet) using a fixed-ratio (1:1) schedule were subsequently placed in a Skinner box in which the lever could be removed randomly. Field postsynaptic potentials (fPSPs) were chronically evoked in perforant pathway-hippocampal CA1 (PP-CA1), CA1-subiculum (CA1-SUB), CA1-medial prefrontal cortex (CA1-mPFC), mPFC-nucleus accumbens (mPFC-NAc), and mPFC-basolateral amygdala (mPFC-BLA) synapses during lever IN and lever OUT situations. While lever presses were accompanied by a significant increase in fPSP slopes at the five synapses, the unpredictable absence of the lever were accompanied by decreased fPSP slopes in all, except PP-CA1 synapses. Spectral analysis of local field potentials (LFPs) recorded when the animal approached the corresponding area in the lever OUT situation presented lower spectral powers than during lever IN occasions for all recording sites, apart from CA1. Thus, the unpredictable availability of a reward-related cue modified the activity of cortical and subcortical areas related with the acquisition of operant learning tasks, suggesting an immediate functional reorganization of these neural circuits to address the changed situation and to modify ongoing behaviors accordingly.
Collapse
Affiliation(s)
- Iván Fernández-Lamo
- Division of Neurosciences, Pablo de Olavide University, Seville-41013, Spain
| | | | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, Seville-41013, Spain
| | | |
Collapse
|
21
|
Abstract
Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.
Collapse
Affiliation(s)
- Ivan Izquierdo
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Cristiane R. G. Furini
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Jociane C. Myskiw
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| |
Collapse
|
22
|
Lin C, Disterhoft J, Weiss C. Whisker-signaled Eyeblink Classical Conditioning in Head-fixed Mice. J Vis Exp 2016:e53310. [PMID: 27077752 DOI: 10.3791/53310] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Eyeblink conditioning is a common paradigm for investigating the neural mechanisms underlying learning and memory. To better utilize the extensive repertoire of scientific techniques available to study learning and memory at the cellular level, it is ideal to have a stable cranial platform. Because mice do not readily tolerate restraint, they are usually trained while moving about freely in a chamber. Conditioned stimulus (CS) and unconditioned stimulus (US) information are delivered and eyeblink responses recorded via a tether connected to the mouse's head. In the head-fixed apparatus presented here, mice are allowed to run as they desire while their heads are secured to facilitate experimentation. Reliable conditioning of the eyeblink response is obtained with this training apparatus, which allows for the delivery of whisker stimulation as the CS, a periorbital electrical shock as the US, and analysis of electromyographic (EMG) activity from the eyelid to detect blink responses.
Collapse
Affiliation(s)
- Carmen Lin
- Department of Physiology, Northwestern University
| | | | - Craig Weiss
- Department of Physiology, Northwestern University;
| |
Collapse
|
23
|
Li SB, Du D, Hasan MT, Köhr G. D4 Receptor Activation Differentially Modulates Hippocampal Basal and Apical Dendritic Synapses in Freely Moving Mice. Cereb Cortex 2016; 26:647-55. [PMID: 25270308 DOI: 10.1093/cercor/bhu229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Activation of D4 receptors (D4Rs) has been shown to improve cognitive performance, potentially affecting synaptic strength. We investigated the D4R agonist PD 168077 (PD) in hippocampal CA1 of freely moving mice. We electrically stimulated in stratum oriens (OR) or radiatum (RAD) and evoked local field potentials (LFPs). Intraperitoneally injected PD dose-dependently and reversibly attenuated LFPs for longer time in basal (OR) than apical (RAD) dendrites. High-frequency stimulation induced LTP that was stronger and more stable in OR than RAD. LTP lasted at least 4 h during which the paired-pulse ratio remained reduced. A PD concentration not affecting synaptic transmission was sufficient to reduce LTP in OR but not in RAD. A PD concentration reducing synaptic transmission reduced the early phase LTP in OR additionally and the late phase LTP in RAD exclusively. Furthermore, cell type-specific expression of mCherry in DATCre mice generated fluorescence in dorsal CA1 that was highest in lacunosum moleculare and similar in OR/RAD, indicating that midbrain dopaminergic fibers distribute evenly in OR/RAD. Together, the D4R-mediated modulation of hippocampal synaptic transmission and plasticity is stronger in OR than RAD. This could affect information processing in CA1 neurons, since signals arriving via basal and apical afferents are distinct.
Collapse
Affiliation(s)
- Shi-Bin Li
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: Physiology of Neural Networks, Psychiatry/Psychopharmacology, Central Institute of Mental Health, J5, Heidelberg University, Mannheim 68159, Germany
| | - Dan Du
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: Physiology of Neural Networks, Psychiatry/Psychopharmacology, Central Institute of Mental Health, J5, Heidelberg University, Mannheim 68159, Germany
| | - Mazahir T Hasan
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: NeuroCure Cluster of Excellence, Charité-Universitätsmedizin, Berlin 12101, Germany
| | - Georg Köhr
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: Physiology of Neural Networks, Psychiatry/Psychopharmacology, Central Institute of Mental Health, J5, Heidelberg University, Mannheim 68159, Germany
| |
Collapse
|
24
|
Delgado-García JM. Cajal and the Conceptual Weakness of Neural Sciences. Front Neuroanat 2015; 9:128. [PMID: 26483644 PMCID: PMC4588005 DOI: 10.3389/fnana.2015.00128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 09/16/2015] [Indexed: 01/21/2023] Open
Abstract
The experimental and conceptual contributions of Santiago Ramón y Cajal remain almost as fresh and valuable as when his original proposals were published more than a century ago-a rare example, contrasting with other related sciences. His basic concepts on the neuron as the main building block of the central nervous system, the dynamic polarization principle as a way to understand how neurons deal with ongoing active processes, and brain local structural arrangements as a result of the functional specialization of selected neural circuits are concepts still surviving in present research papers dealing with brain function during the performance of cognitive and/or behavioral activities. What is more, the central dogma of the Neuroscience of today, i.e., brain plasticity as the morpho-functional substrate of memory and learning processes, was already proposed and documented with notable insights by Ramón y Cajal. From this background, I will try to discuss in this chapter which new functional and structural concepts have been introduced in contemporary Neuroscience and how we will be able to construct a set of basic principles underlying brain functions for the twenty-first century.
Collapse
|
25
|
Kim WR, Lee JW, Sun W, Lee SH, Choi JS, Jung MW. Effect of dentate gyrus disruption on remembering what happened where. Front Behav Neurosci 2015; 9:170. [PMID: 26175676 PMCID: PMC4485174 DOI: 10.3389/fnbeh.2015.00170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/18/2015] [Indexed: 12/24/2022] Open
Abstract
Our previous studies using Bax knockout (Bax-KO) mice, in which newly generated granule cells continue to accumulate, disrupting neural circuitry specifically in the dentate gyrus (DG), suggest the involvement of the DG in binding the internally-generated spatial map with sensory information on external landmarks (spatial map-object association) in forming a distinct spatial context for each environment. In order to test whether the DG is also involved in binding the internal spatial map with sensory information on external events (spatial map-event association), we tested the behavior of Bax-KO mice in a delayed-non-match-to-place task. Performance of Bax-KO mice was indistinguishable from that of wild-type mice as long as there was no interruption during the delay period (tested up to 5 min), suggesting that on-line maintenance of working memory is intact in Bax-KO mice. However, Bax-KO mice showed profound performance deficits when they were removed from the maze during the delay period (interruption condition) with a sufficiently long (65 s) delay, suggesting that episodic memory was impaired in Bax-KO mice. Together with previous findings, these results suggest the role of the DG in binding spatial information derived from dead reckoning and nonspatial information, such as external objects and events, in the process of encoding episodic memory.
Collapse
Affiliation(s)
- Woon Ryoung Kim
- Department of Anatomy, College of Medicine, Korea University Seoul, Korea
| | - Jong Won Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science Daejeon, Korea
| | - Woong Sun
- Department of Anatomy, College of Medicine, Korea University Seoul, Korea
| | - Sung-Hyun Lee
- Neuroscience Graduate Program, Ajou University School of Medicine Suwon, Korea
| | | | - Min Whan Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science Daejeon, Korea ; Neuroscience Graduate Program, Ajou University School of Medicine Suwon, Korea ; Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, Korea
| |
Collapse
|
26
|
Chew B, Ryu JR, Ng T, Ma D, Dasgupta A, Neo SH, Zhao J, Zhong Z, Bichler Z, Sajikumar S, Goh ELK. Lentiviral silencing of GSK-3β in adult dentate gyrus impairs contextual fear memory and synaptic plasticity. Front Behav Neurosci 2015; 9:158. [PMID: 26157370 PMCID: PMC4477161 DOI: 10.3389/fnbeh.2015.00158] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 06/01/2015] [Indexed: 11/13/2022] Open
Abstract
Attempts have been made to use glycogen synthase kinase-3 beta (GSK3β) inhibitors for prophylactic treatment of neurocognitive conditions. However the use of lithium, a non-specific inhibitor of GSK3β results in mild cognitive impairment in humans. The effects of global GSK3β inhibition or knockout on learning and memory in healthy adult mice are also inconclusive. Our study aims to better understand the role of GSK3β in learning and memory through a more regionally, targeted approach, specifically performing lentiviral-mediated knockdown of GSK3β within the dentate gyrus (DG). DG-GSK3β-silenced mice showed impaired contextual fear memory retrieval. However, cue fear memory, spatial memory, locomotor activity and anxiety levels were similar to control. These GSK3β-silenced mice also showed increased induction and maintenance of DG long-term potentiation (DG-LTP) compared to control animals. Thus, this region-specific, targeted knockdown of GSK3β in the DG provides better understanding on the role of GSK3β in learning and memory.
Collapse
Affiliation(s)
- Benjamin Chew
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, Singapore
| | - Jae Ryun Ryu
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, Singapore
| | - Teclise Ng
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, Singapore
| | - Dongliang Ma
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, Singapore
| | - Ananya Dasgupta
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Sin Hui Neo
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Jing Zhao
- Regenerative Medicine DPU, GlaxoSmithKline (China) R&D Co., Ltd. Shanghai, China
| | - Zhong Zhong
- Regenerative Medicine DPU, GlaxoSmithKline (China) R&D Co., Ltd. Shanghai, China
| | - Zoë Bichler
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, Singapore ; Behavioural Neuroscience Laboratory, National Neuroscience Institute Singapore, Singapore
| | - Sreedharan Sajikumar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Eyleen L K Goh
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, Singapore ; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore ; KK Research Center, KK Women's and Children's Hospital Singapore, Singapore
| |
Collapse
|
27
|
Gruart A, Leal-Campanario R, López-Ramos JC, Delgado-García JM. Functional basis of associative learning and its relationships with long-term potentiation evoked in the involved neural circuits: Lessons from studies in behaving mammals. Neurobiol Learn Mem 2015; 124:3-18. [PMID: 25916668 DOI: 10.1016/j.nlm.2015.04.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 12/27/2022]
Abstract
While contemporary neuroscience is paying increasing attention to subcellular and molecular events and other intracellular phenomena underlying the acquisition, storage, and retrieval of newly acquired motor and cognitive abilities, parallel attention should be paid to the study of the electrophysiological phenomena taking place at selected cortical and subcortical neuronal and synaptic sites during the precise moment of learning acquisition, extinction, and recall. These in vivo approaches to the study of learning and memory processes will allow the proper integration of the important information collected from in vitro and delayed molecular studies. Here, we summarize studies in behaving mammals carried out in our laboratory during the past ten years on the relationships between experimentally evoked long-term potentiation (LTP) and activity-dependent changes in synaptic strength taking place in hippocampal, prefrontal and related cortical and subcortical circuits during the acquisition of classical eyeblink conditioning or operant learning tasks. These studies suggest that different hippocampal synapses are selectively modified in strength during the acquisition of classical, but not instrumental, learning tasks. In contrast, selected prefrontal and striatum synapses are more directly modified by operant conditioning. These studies also show that besides N-methyl-D-aspartate (NMDA) receptors, many other neurotransmitter, intracellular mediating, and transcription factors participate in these two types of associative learning. Although experimentally evoked LTP seems to prevent the acquisition of classical eyeblink conditioning when induced at selected hippocampal synapses, it proved to be ineffective in preventing the acquisition of operant conditioned tasks when induced at numerous hippocampal, prefrontal, and striatal sites. The differential roles of these cortical structures during these two types of associative learning are discussed, and a diagrammatic representation of their respective functions is presented.
Collapse
Affiliation(s)
- Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, Seville 41013, Spain.
| | | | | | | |
Collapse
|
28
|
Hoffmann LC, Cicchese JJ, Berry SD. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning. Front Syst Neurosci 2015; 9:50. [PMID: 25918501 PMCID: PMC4394696 DOI: 10.3389/fnsys.2015.00050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 03/12/2015] [Indexed: 12/17/2022] Open
Abstract
Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3–12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3–7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning.
Collapse
Affiliation(s)
- Loren C Hoffmann
- Center for Learning and Memory, University of Texas Austin, TX, USA
| | - Joseph J Cicchese
- Department of Psychology and Center for Neuroscience, Miami University Oxford, OH, USA
| | - Stephen D Berry
- Department of Psychology and Center for Neuroscience, Miami University Oxford, OH, USA
| |
Collapse
|
29
|
Faghihi F, Moustafa AA. A computational model of pattern separation efficiency in the dentate gyrus with implications in schizophrenia. Front Syst Neurosci 2015; 9:42. [PMID: 25859189 PMCID: PMC4373261 DOI: 10.3389/fnsys.2015.00042] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/05/2015] [Indexed: 11/13/2022] Open
Abstract
Information processing in the hippocampus begins by transferring spiking activity of the entorhinal cortex (EC) into the dentate gyrus (DG). Activity pattern in the EC is separated by the DG such that it plays an important role in hippocampal functions including memory. The structural and physiological parameters of these neural networks enable the hippocampus to be efficient in encoding a large number of inputs that animals receive and process in their life time. The neural encoding capacity of the DG depends on its single neurons encoding and pattern separation efficiency. In this study, encoding by the DG is modeled such that single neurons and pattern separation efficiency are measured using simulations of different parameter values. For this purpose, a probabilistic model of single neurons efficiency is presented to study the role of structural and physiological parameters. Known neurons number of the EC and the DG is used to construct a neural network by electrophysiological features of granule cells of the DG. Separated inputs as activated neurons in the EC with different firing probabilities are presented into the DG. For different connectivity rates between the EC and DG, pattern separation efficiency of the DG is measured. The results show that in the absence of feedback inhibition on the DG neurons, the DG demonstrates low separation efficiency and high firing frequency. Feedback inhibition can increase separation efficiency while resulting in very low single neuron's encoding efficiency in the DG and very low firing frequency of neurons in the DG (sparse spiking). This work presents a mechanistic explanation for experimental observations in the hippocampus, in combination with theoretical measures. Moreover, the model predicts a critical role for impaired inhibitory neurons in schizophrenia where deficiency in pattern separation of the DG has been observed.
Collapse
Affiliation(s)
- Faramarz Faghihi
- Center for Neural Informatics, Structures, and Plasticity, Krasnow Institute for Advanced Study, George Mason University Fairfax, VA, USA
| | - Ahmed A Moustafa
- Department of Veterans Affairs, VA New Jersey Health Care System East Orange, NJ, USA ; School of Social Sciences and Psychology and Marcs Institute for Brain and Behaviour, University of Western Sydney Sydney NSW, Australia
| |
Collapse
|
30
|
Nauer RK, Whiteman AS, Dunne MF, Stern CE, Schon K. Hippocampal subfield and medial temporal cortical persistent activity during working memory reflects ongoing encoding. Front Syst Neurosci 2015; 9:30. [PMID: 25859188 PMCID: PMC4372545 DOI: 10.3389/fnsys.2015.00030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/18/2015] [Indexed: 11/13/2022] Open
Abstract
Previous neuroimaging studies support a role for the medial temporal lobes in maintaining novel stimuli over brief working memory (WM) delays, and suggest delay period activity predicts subsequent memory. Additionally, slice recording studies have demonstrated neuronal persistent spiking in entorhinal cortex, perirhinal cortex (PrC), and hippocampus (CA1, CA3, subiculum). These data have led to computational models that suggest persistent spiking in parahippocampal regions could sustain neuronal representations of sensory information over many seconds. This mechanism may support both WM maintenance and encoding of information into long term episodic memory. The goal of the current study was to use high-resolution fMRI to elucidate the contributions of the MTL cortices and hippocampal subfields to WM maintenance as it relates to later episodic recognition memory. We scanned participants while they performed a delayed match to sample task with novel scene stimuli, and assessed their memory for these scenes post-scan. We hypothesized stimulus-driven activation that persists into the delay period-a putative correlate of persistent spiking-would predict later recognition memory. Our results suggest sample and delay period activation in the parahippocampal cortex (PHC), PrC, and subiculum (extending into DG/CA3 and CA1) was linearly related to increases in subsequent memory strength. These data extend previous neuroimaging studies that have constrained their analysis to either the sample or delay period by modeling these together as one continuous ongoing encoding process, and support computational frameworks that predict persistent activity underlies both WM and episodic encoding.
Collapse
Affiliation(s)
- Rachel K. Nauer
- Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, MAUSA
- Brain Plasticity and Neuroimaging Laboratory, Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MAUSA
| | - Andrew S. Whiteman
- Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, MAUSA
| | - Matthew F. Dunne
- Brain Plasticity and Neuroimaging Laboratory, Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MAUSA
| | - Chantal E. Stern
- Brain Plasticity and Neuroimaging Laboratory, Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MAUSA
| | - Karin Schon
- Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, MAUSA
- Brain Plasticity and Neuroimaging Laboratory, Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MAUSA
| |
Collapse
|
31
|
Yang Y, Lei C, Feng H, Sui JF. The neural circuitry and molecular mechanisms underlying delay and trace eyeblink conditioning in mice. Behav Brain Res 2014; 278:307-14. [PMID: 25448430 DOI: 10.1016/j.bbr.2014.10.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/28/2014] [Accepted: 10/02/2014] [Indexed: 11/30/2022]
Abstract
Classical eyeblink conditioning (EBC), a simple form of associative learning, has long been served as a model for motor learning and modulation. The neural circuitry of EBC has been studied in detail in rabbits. However, its underlying molecular mechanisms remain unclear. The advent of mouse transgenics has generated new perspectives on the studies of the neural substrates and molecular mechanisms essential for EBC. Results about EBC in mice differ in some aspects from those obtained in other mammals. Here, we review the current studies about the neural circuitry and molecular mechanisms underlying delay and trace EBC in mice. We conclude that brainstem-cerebellar circuit plays an essential role in DEC while the amygdala modulates this process, and that the medial prefrontal cortex (mPFC) as a candidate is involved in the extra-cerebellar mechanism underlying delay eyeblink conditioning (DEC) in mice. We propose the Amygdala-Cerebellum-Prefrontal Cortex-Dynamic-Conditioning Model (ACPDC model) for DEC in mice. As to trace eyeblink conditioning (TEC), the forebrain regions may play an essential role in it, whereas cerebellar cortex seems to be out of the neural circuitry in mice. Moreover, the molecular mechanisms underlying DEC and TEC in mice differ from each other. This review provides some new information and perspectives for further research on EBC.
Collapse
Affiliation(s)
- Yi Yang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China; Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China
| | - Chen Lei
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, PR China
| | - Jian-feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China; Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China.
| |
Collapse
|