Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace

In the brain, neuronal gene expression is dynamically changed in response to neuronal activity. In particular, the expression of immediate-early genes (IEGs) such as egr-1, c-fos, and Arc is rapidly and selectively upregulated in subsets of neurons in specific brain regions associated with learning...

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Main Authors: Keiichiro eMinatohara, Mika eAkiyoshi, Hiroyuki eOkuno
Format: Article
Language:English
Published: Frontiers Media S.A. 2016-01-01
Series:Frontiers in Molecular Neuroscience
Subjects:
Online Access:http://journal.frontiersin.org/Journal/10.3389/fnmol.2015.00078/full
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author Keiichiro eMinatohara
Mika eAkiyoshi
Hiroyuki eOkuno
author_facet Keiichiro eMinatohara
Mika eAkiyoshi
Hiroyuki eOkuno
author_sort Keiichiro eMinatohara
collection DOAJ
description In the brain, neuronal gene expression is dynamically changed in response to neuronal activity. In particular, the expression of immediate-early genes (IEGs) such as egr-1, c-fos, and Arc is rapidly and selectively upregulated in subsets of neurons in specific brain regions associated with learning and memory formation. IEG expression has therefore been widely used as a molecular marker for neuronal populations that undergo plastic changes underlying formation of long-term memory. In recent years, optogenetic and pharmacogenetic studies of neurons expressing c-fos or Arc have revealed that, during learning, IEG-positive neurons encode and store information that is required for memory recall, suggesting that they may be involved in formation of the memory trace. However, despite accumulating evidence for the role of IEGs in synaptic plasticity, the molecular and cellular mechanisms associated with this process remain unclear. In this review, we first summarize recent literature concerning the role of IEG-expressing neuronal ensembles in organizing the memory trace. We then focus on the physiological significance of IEGs, especially Arc, in synaptic plasticity, and describe our hypotheses about the importance of Arc expression in various types of input-specific circuit reorganization. Finally, we offer perspectives on Arc function that would unveil the role of IEG-expressing neurons in the formation of memory traces in the hippocampus and other brain areas.
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spelling doaj.art-d0b0155adcc1441eb8a14c3934b3da9e2022-12-22T01:27:34ZengFrontiers Media S.A.Frontiers in Molecular Neuroscience1662-50992016-01-01810.3389/fnmol.2015.00078172311Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory traceKeiichiro eMinatohara0Mika eAkiyoshi1Hiroyuki eOkuno2Kyoto UniversityKyoto UniversityKyoto UniversityIn the brain, neuronal gene expression is dynamically changed in response to neuronal activity. In particular, the expression of immediate-early genes (IEGs) such as egr-1, c-fos, and Arc is rapidly and selectively upregulated in subsets of neurons in specific brain regions associated with learning and memory formation. IEG expression has therefore been widely used as a molecular marker for neuronal populations that undergo plastic changes underlying formation of long-term memory. In recent years, optogenetic and pharmacogenetic studies of neurons expressing c-fos or Arc have revealed that, during learning, IEG-positive neurons encode and store information that is required for memory recall, suggesting that they may be involved in formation of the memory trace. However, despite accumulating evidence for the role of IEGs in synaptic plasticity, the molecular and cellular mechanisms associated with this process remain unclear. In this review, we first summarize recent literature concerning the role of IEG-expressing neuronal ensembles in organizing the memory trace. We then focus on the physiological significance of IEGs, especially Arc, in synaptic plasticity, and describe our hypotheses about the importance of Arc expression in various types of input-specific circuit reorganization. Finally, we offer perspectives on Arc function that would unveil the role of IEG-expressing neurons in the formation of memory traces in the hippocampus and other brain areas.http://journal.frontiersin.org/Journal/10.3389/fnmol.2015.00078/fullc-fossynaptic plasticityArcimmediate-early genememory traceneuronal ensemble
spellingShingle Keiichiro eMinatohara
Mika eAkiyoshi
Hiroyuki eOkuno
Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
Frontiers in Molecular Neuroscience
c-fos
synaptic plasticity
Arc
immediate-early gene
memory trace
neuronal ensemble
title Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
title_full Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
title_fullStr Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
title_full_unstemmed Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
title_short Role of immediate-early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
title_sort role of immediate early genes in synaptic plasticity and neuronal ensembles underlying the memory trace
topic c-fos
synaptic plasticity
Arc
immediate-early gene
memory trace
neuronal ensemble
url http://journal.frontiersin.org/Journal/10.3389/fnmol.2015.00078/full
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AT hiroyukieokuno roleofimmediateearlygenesinsynapticplasticityandneuronalensemblesunderlyingthememorytrace