Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Efficient partitioning of memory systems and its importance for memory consolidation.

ABSTRACT: Long-term memories are likely stored in the synaptic weights of neuronal networks in the brain. The storage capacity of such networks depends on the degree of plasticity of their synapses. Highly plastic synapses allow for strong memories, but these are quickly overwritten. On the other hand, less labile synapses result in long-lasting but weak memories. Here we show that the trade-off between memory strength and memory lifetime can be overcome by partitioning the memory system into multiple regions characterized by different levels of synaptic plasticity and transferring memory information from the more to less plastic region. The improvement in memory lifetime is proportional to the number of memory regions, and the initial memory strength can be orders of magnitude larger than in a non-partitioned memory system. This model provides a fundamental computational reason for memory consolidation processes at the systems level.

SUBMITTER: Roxin A

PROVIDER: S-EPMC3723499 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Efficient partitioning of memory systems and its importance for memory consolidation.

Roxin Alex A Fusi Stefano S

PLoS computational biology 20130725 7

Long-term memories are likely stored in the synaptic weights of neuronal networks in the brain. The storage capacity of such networks depends on the degree of plasticity of their synapses. Highly plastic synapses allow for strong memories, but these are quickly overwritten. On the other hand, less labile synapses result in long-lasting but weak memories. Here we show that the trade-off between memory strength and memory lifetime can be overcome by partitioning the memory system into multiple reg ...[more]

PMID: 23935470

Similar Datasets

Concurrent synaptic and systems memory consolidation during sleep.

Project description:Memories are consolidated during sleep by two apparently antagonistic processes: (1) reinforcement of memory-specific cortical interactions and (2) homeostatic reduction in synaptic efficiency. Using fMRI, we assessed whether episodic memories are processed during sleep by either or both mechanisms, by comparing recollection before and after sleep. We probed whether LTP influences these processes by contrasting two groups of individuals prospectively recruited based on BDNF rs6265 (Val66Met) polymorphism. Between immediate retrieval and delayed testing scheduled after sleep, responses to recollection increased significantly more in Val/Val individuals than in Met carriers in parietal and occipital areas not previously engaged in retrieval, consistent with "systems-level consolidation." Responses also increased differentially between allelic groups in regions already activated before sleep but only in proportion to slow oscillation power, in keeping with "synaptic downscaling." Episodic memories seem processed at both synaptic and systemic levels during sleep by mechanisms involving LTP.

| S-EPMC6618390 | biostudies-literature

Rehearsal initiates systems memory consolidation, sleep makes it last.

Project description:After encoding, memories undergo a transitional process termed systems memory consolidation. It allows fast acquisition of new information by the hippocampus, as well as stable storage in neocortical long-term networks, where memory is protected from interference. Whereas this process is generally thought to occur slowly over time and sleep, we recently found a rapid memory systems transition from hippocampus to posterior parietal cortex (PPC) that occurs over repeated rehearsal within one study session. Here, we use fMRI to demonstrate that this transition is stabilized over sleep, whereas wakefulness leads to a reset to naïve responses, such as observed during early encoding. The role of sleep therefore seems to go beyond providing additional rehearsal through memory trace reactivation, as previously thought. We conclude that repeated study induces systems consolidation, while sleep ensures that these transformations become stable and long lasting. Thus, sleep and repeated rehearsal jointly contribute to long-term memory consolidation.

| S-EPMC6482015 | biostudies-literature

Synaptic weight dynamics underlying systems consolidation of a memory.

Project description:Systems consolidation is a common feature of learning and memory systems, in which a long-term memory initially stored in one brain region becomes persistently stored in another region. We studied the dynamics of systems consolidation in simple circuit architectures modeling core features of many memory systems: an early- and late-learning brain region and two sites of plasticity. We show that the synaptic dynamics of the circuit during consolidation of an analog memory can be understood as a temporal integration process, by which transient changes in activity driven by plasticity in the early-learning area are accumulated into persistent synaptic changes at the late-learning site. This simple principle leads to two constraints on the circuit operation for consolidation to be implemented successfully. First, the plasticity rule at the late-learning site must stably support a continuum of possible outputs for a given input. We show that this is readily achieved by heterosynaptic but not standard Hebbian rules, that it naturally leads to a speed-accuracy tradeoff in systems consolidation, and that it provides a concrete circuit instantiation for how systems consolidation solves the stability-plasticity dilemma. Second, to turn off the consolidation process and prevent erroneous changes at the late-learning site, neural activity in the early-learning area must be reset to its baseline activity. We propose two biologically plausible implementations for this reset that suggest novel roles for core elements of the cerebellar circuit.

| S-EPMC10996481 | biostudies-literature

A contextual binding theory of episodic memory: systems consolidation reconsidered.

Project description:Episodic memory reflects the ability to recollect the temporal and spatial context of past experiences. Episodic memories depend on the hippocampus but have been proposed to undergo rapid forgetting unless consolidated during offline periods such as sleep to neocortical areas for long-term storage. Here, we propose an alternative to this standard systems consolidation theory (SSCT) - a contextual binding account - in which the hippocampus binds item-related and context-related information. We compare these accounts in light of behavioural, lesion, neuroimaging and sleep studies of episodic memory and contend that forgetting is largely due to contextual interference, episodic memory remains dependent on the hippocampus across time, contextual drift produces post-encoding activity and sleep benefits memory by reducing contextual interference.

| S-EPMC7233541 | biostudies-literature

Engrams and circuits crucial for systems consolidation of a memory.

Project description:Episodic memories initially require rapid synaptic plasticity within the hippocampus for their formation and are gradually consolidated in neocortical networks for permanent storage. However, the engrams and circuits that support neocortical memory consolidation have thus far been unknown. We found that neocortical prefrontal memory engram cells, which are critical for remote contextual fear memory, were rapidly generated during initial learning through inputs from both the hippocampal-entorhinal cortex network and the basolateral amygdala. After their generation, the prefrontal engram cells, with support from hippocampal memory engram cells, became functionally mature with time. Whereas hippocampal engram cells gradually became silent with time, engram cells in the basolateral amygdala, which were necessary for fear memory, were maintained. Our data provide new insights into the functional reorganization of engrams and circuits underlying systems consolidation of memory.

| S-EPMC5493329 | biostudies-literature

Optogenetic reactivation of memory ensembles in the retrosplenial cortex induces systems consolidation.

Project description:The neural circuits underlying memory change over prolonged periods after learning, in a process known as systems consolidation. Postlearning spontaneous reactivation of memory-related neural ensembles is thought to mediate this process, although a causal link has not been established. Here we test this hypothesis in mice by using optogenetics to selectively reactivate neural ensembles representing a contextual fear memory (sometimes referred to as engram neurons). High-frequency stimulation of these ensembles in the retrosplenial cortex 1 day after learning produced a recent memory with features normally observed in consolidated remote memories, including higher engagement of neocortical areas during retrieval, contextual generalization, and decreased hippocampal dependence. Moreover, this effect was only present if memory ensembles were reactivated during sleep or light anesthesia. These results provide direct support for postlearning memory ensemble reactivation as a mechanism of systems consolidation, and show that this process can be accelerated by ensemble reactivation in an unconscious state.

| S-EPMC6486739 | biostudies-literature

Hebbian plasticity in parallel synaptic pathways: A circuit mechanism for systems memory consolidation.

Project description:Systems memory consolidation involves the transfer of memories across brain regions and the transformation of memory content. For example, declarative memories that transiently depend on the hippocampal formation are transformed into long-term memory traces in neocortical networks, and procedural memories are transformed within cortico-striatal networks. These consolidation processes are thought to rely on replay and repetition of recently acquired memories, but the cellular and network mechanisms that mediate the changes of memories are poorly understood. Here, we suggest that systems memory consolidation could arise from Hebbian plasticity in networks with parallel synaptic pathways-two ubiquitous features of neural circuits in the brain. We explore this hypothesis in the context of hippocampus-dependent memories. Using computational models and mathematical analyses, we illustrate how memories are transferred across circuits and discuss why their representations could change. The analyses suggest that Hebbian plasticity mediates consolidation by transferring a linear approximation of a previously acquired memory into a parallel pathway. Our modelling results are further in quantitative agreement with lesion studies in rodents. Moreover, a hierarchical iteration of the mechanism yields power-law forgetting-as observed in psychophysical studies in humans. The predicted circuit mechanism thus bridges spatial scales from single cells to cortical areas and time scales from milliseconds to years.

| S-EPMC8683039 | biostudies-literature

Systems consolidation induces multiple memory engrams for a flexible recall strategy in observational fear memory in male mice.

Project description:Observers learn to fear the context in which they witnessed a demonstrator's aversive experience, called observational contextual fear conditioning (CFC). The neural mechanisms governing whether recall of the observational CFC memory occurs from the observer's own or from the demonstrator's point of view remain unclear. Here, we show in male mice that recent observational CFC memory is recalled in the observer's context only, but remote memory is recalled in both observer and demonstrator contexts. Recall of recent memory in the observer's context requires dorsal hippocampus activity, while recall of remote memory in both contexts requires the medial prefrontal cortex (mPFC)-basolateral amygdala pathway. Although mPFC neurons activated by observational CFC are involved in remote recall in both contexts, distinct mPFC subpopulations regulate remote recall in each context. Our data provide insights into a flexible recall strategy and the functional reorganization of circuits and memory engram cells underlying observational CFC memory.

| S-EPMC10322999 | biostudies-literature

FoxO6 regulates memory consolidation and synaptic function.

Project description:We used microarrays to assess gene expression differences in the hippocampus between FoxO6 mutant and wild-type siblings before (basal) or after novel object learning. The cohort of basal mice were housed individually for at least 3 days prior to tissue harvesting. The mice used to collect hippocampal samples after the object learning task were handled daily in the procedure room, prior to the object learning task. 24 hours before the object learning task, each mouse was individually habituated to the empty novel object arena for 10 min. On the days of the novel object learning task and the empty arena habituation, the mice were transferred to the procedure room and acclimatized for 60 min. For the novel object learning task, the mice were allowed to explore two identical and novel objects for 10 min in a 70 x 70 x 70 cm black plastic arena with a white PVC vinyl material on the base. After the object exploration, mice were transferred to an empty cage, and were euthanized after 60 min. The brains were dissected and incubated in ice-cold RNAlater (Ambion) for 24 hours at 4M-BM-:C. The brains were then rapidly frozen in O.C.T. Tissue-Tek (Sakura) at -80M-BM-:C. Coronal brain sections (300 M-BM-5m) were made using a microtome (Microm), the hippocampus was finely dissected and collected into M-bM-^@M-^XRNA lysis bufferM-bM-^@M-^Y (Ambion), and homogenized for 30 sec using a rotar-stat homogenizer. Total RNA was extracted using the RNAqueous column (Ambion) following the manufacturerM-bM-^@M-^Ys protocol.

2012-11-08 | E-GEOD-42097 | biostudies-arrayexpress

miRNA and consolidation of cued fear memory

Project description:miRNA profiling was carried out using the miRCURY LNA™ microRNA Array (6th gen - hsa, mmu & rno) miRNA were profiled in amygdala brain tissue obtained from adult mice 30 mins after auditory fear conditioning and expression levels compared to tissue obtained from Home cage controls Adult male mice were fear conditioned using tone-shock pairings and brains were harvested 30 mins later. The brains of Home Cage controls and Fear Conditioned animals (n = 4/group) were then punched to collect amygdala tissue. miRNA were extracted using the Qiagen miRNeasy Kit, and then shipped to Exiqon. Exiqon performed labeling, hybridization and data analysis after use of the miRCURY LNA™ microRNA Array (6th gen - hsa, mmu & rno). https://www.exiqon.com/ls/Documents/Scientific/miRCURY-LNA-microRNA-Array-6th-gen-hsa-mmu-rno-manual.pdf

2014-09-30 | E-GEOD-59072 | biostudies-arrayexpress

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data