Memory engrams: Recalling the past and imagining the future

Science, Journal Year: 2020, Volume and Issue: 367(6473)

Published: Jan. 3, 2020

In 1904, Richard Semon introduced the term "engram" to describe neural substrate for storing memories. An experience, proposed, activates a subset of cells that undergo off-line, persistent chemical and/or physical changes become an engram. Subsequent reactivation this engram induces memory retrieval. Although Semon's contributions were largely ignored in his lifetime, new technologies allow researchers image and manipulate brain at level individual neurons has reinvigorated research. We review recent progress studying engrams, including evaluation evidence existence importance intrinsic excitability synaptic plasticity lifetime Together, these findings are beginning define as basic unit memory.

Language: Английский

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Beyond the Status Quo: A Role for Beta Oscillations in Endogenous Content (Re)Activation

eNeuro, Journal Year: 2017, Volume and Issue: 4(4), P. ENEURO.0170 - 17.2017

Published: July 1, 2017

Among the rhythms of brain, oscillations in beta frequency range (∼13-30 Hz) have been considered most enigmatic. Traditionally associated with sensorimotor functions, recently become more broadly implicated top-down processing, long-range communication, and preservation current brain state. Here, we extend refine these views based on accumulating new findings content-specific beta-synchronization during endogenous information processing working memory (WM) decision making. We characterize such activity as short-lived, flexible network dynamics supporting (re)activation cortical representations. Specifically, suggest that beta-mediated ensemble formation within between areas may awake, rather than merely preserve, an cognitive set service task demands. This proposal accommodates key aspects modulations monkeys humans, integrates timely computational models, outlines a functional role for fits its transient temporal characteristics.

Language: Английский

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Memory Allocation: Mechanisms and Function

Annual Review of Neuroscience, Journal Year: 2018, Volume and Issue: 41(1), P. 389 - 413

Published: May 1, 2018

Memories for events are thought to be represented in sparse, distributed neuronal ensembles (or engrams). In this article, we review how neurons chosen become part of a particular engram, via process allocation. Experiments rodents indicate that eligible compete allocation given with more excitable winning competition. Moreover, fluctuations excitability determine engrams interact, promoting either memory integration (via coallocation overlapping engrams) or separation disallocation nonoverlapping parallel rodent studies, recent findings humans verify the importance linking memories occur close time share related content. A deeper understanding promises provide insights into logic underlying knowledge is normally organized brain and disorders which has gone awry.

Language: Английский

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Getting rid of visual distractors: the why, when, how, and where

Current Opinion in Psychology, Journal Year: 2019, Volume and Issue: 29, P. 135 - 147

Published: Feb. 14, 2019

Language: Английский

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Forgetting as a form of adaptive engram cell plasticity

Nature reviews. Neuroscience, Journal Year: 2022, Volume and Issue: 23(3), P. 173 - 186

Published: Jan. 13, 2022

Language: Английский

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The role of inhibitory circuits in hippocampal memory processing

Nature reviews. Neuroscience, Journal Year: 2022, Volume and Issue: 23(8), P. 476 - 492

Published: May 30, 2022

Language: Английский

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Precise excitation-inhibition balance controls gain and timing in the hippocampus

eLife, Journal Year: 2019, Volume and Issue: 8

Published: April 25, 2019

Excitation-inhibition (EI) balance controls excitability, dynamic range, and input gating in many brain circuits. Subsets of synaptic can be selected or 'gated' by precise modulation finely tuned EI balance, but assessing the granularity requires combinatorial analysis excitatory inhibitory inputs. Using patterned optogenetic stimulation mouse hippocampal CA3 neurons, we show that hundreds unique combinations recruit excitation inhibition with a nearly identical ratio, demonstrating at hippocampus. Crucially, delay between decreases as increases from few synapses to tens synapses. This creates millisecond-range window for postsynaptic excitation, controlling membrane depolarization amplitude timing via subthreshold divisive normalization. We suggest this combination delays forms general mechanism gain control feedforward networks.

Language: Английский

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Economic Choice as an Untangling of Options into Actions

Neuron, Journal Year: 2018, Volume and Issue: 99(3), P. 434 - 447

Published: Aug. 1, 2018

Language: Английский

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The Hippocampus and Neocortical Inhibitory Engrams Protect against Memory Interference

Neuron, Journal Year: 2018, Volume and Issue: 101(3), P. 528 - 541.e6

Published: Dec. 20, 2018

Our experiences often overlap with each other, yet we are able to selectively recall individual memories guide decisions and future actions. The neural mechanisms that support such precise memory remain unclear. Here, using ultra-high field 7T MRI reveal two distinct protect from interference. first mechanism involves the hippocampus, where blood-oxygen-level-dependent (BOLD) signal predicts behavioral measures of interference, representations context-dependent pattern separated according their relational overlap. second neocortical inhibition. When reduce concentration GABA trans-cranial direct current stimulation (tDCS), interference increases in proportion reduction GABA, which turn performance. These findings suggest is mediated by both hippocampus neocortex, separates overlapping but information, inhibition prevents unwanted co-activation between memories.

Language: Английский

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The Synaptic Theory of Memory: A Historical Survey and Reconciliation of Recent Opposition

Frontiers in Systems Neuroscience, Journal Year: 2018, Volume and Issue: 12

Published: Oct. 26, 2018

Trettenbrein (2016, Frontiers in Systems Neuroscience, 10:88) has argued that the concept of synapse as locus memory is outdated and made six critiques this concept. In paper we examine these suggest current theories neurobiology empirical data indicate synaptic activation first step a chain cellular biochemical events lead to memories formed cell assemblies neural networks rely on modification for their formation. These modified connections can account cognitive basis learning deterioration neurological disorders. We discuss Hebb's (1949) theory change formation phase sequences link neurophysiology processes. then each Trettenbrein's (2016) light recent data. subcellular necessity form underlying memory. provide evidence value integrating neurophysiological conceptions some Hebbian conclude with an examination applications Hebb assembly study neuroscience memory, development computational models construction 'intelligent' robots. not died but come dominate our understanding

Language: Английский

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