The Memory Engram

2021 ◽  
pp. 119-128
Keyword(s):  
Memory Engram

Oh Memory Engram, Where Art Thou?

1974 ◽  
Vol 19 (7) ◽  
pp. 524-525 ◽  
Author(s):  
JAMES O'BRIEN
Keyword(s):  
Memory Engram

Dynamic and heterogeneous neural ensembles contribute to a memory engram

2021 ◽  
Vol 67 ◽  
pp. 199-206
Author(s):  
Brian M Sweis ◽  
William Mau ◽  
Sima Rabinowitz ◽  
Denise J Cai
Keyword(s):  
Neural Ensembles ◽  
Memory Engram

scholarly journals Selective increase of functional network connectivity in Arc-positive neuronal engrams after long-term potentiation

2020 ◽  
Author(s):  
Yuheng Jiang ◽  
Antonius M.J. VanDongen
Keyword(s):  
Functional Connectivity ◽  
Hippocampal Neurons ◽  
Network Effects ◽  
Network Connectivity ◽  
Long Term Potentiation ◽  
Early Gene ◽  
Memory Traces ◽  
Term Potentiation ◽  
Memory Engram

ABSTRACTNew tools in optogenetics and molecular biology have culminated in recent studies which mark immediate-early gene (IEG)-expressing neurons as memory traces or engrams. Although the activity-dependent expression of IEGs has been successfully utilised to label memory traces, their roles in engram specification is incompletely understood. Outstanding questions remain as to whether expression of IEGs can interplay with network properties such as functional connectivity and also if neurons expressing different IEGs are functionally distinct. We investigated the expression of Arc and c-Fos, two commonly utilised IEGs in memory engram specification, in cultured hippocampal neurons. After pharmacological induction of long-term potentiation (LTP) in the network, we noted an emergent network property of refinement in functional connectivity between neurons, characterized by a global down-regulation of network connectivity, together with strengthening of specific connections. Subsequently, we show that Arc expression correlates with the effects of network refinement, with Arc-positive neurons being selectively strengthened. Arc positive neurons were also found to be located in closer physical proximity to each other in the network. While the expression pattern of IEGs c-Fos and Arc strongly overlaps, Arc was more selectively expressed than c-Fos. These IEGs also act together in coding information about connection strength pruning. These results demonstrate important links between IEG expression and network connectivity, which serve to bridge the gap between cellular correlates and network effects in learning and memory.

scholarly journals Memory Engram Cells Have Come of Age

Neuron ◽  
2015 ◽  
Vol 87 (5) ◽  
pp. 918-931 ◽  
Author(s):  
Susumu Tonegawa ◽  
Xu Liu ◽  
Steve Ramirez ◽  
Roger Redondo
Keyword(s):  
Memory Engram

Social memory engram in the hippocampus

2018 ◽  
Vol 129 ◽  
pp. 17-23 ◽  
Author(s):  
Teruhiro Okuyama
Keyword(s):  
Social Memory ◽  
Memory Engram

scholarly journals Restoring persistent accessibility to memories after sleep deprivation-induced amnesia

2021 ◽  
Author(s):  
Youri G Bolsius ◽  
Pim Heckman ◽  
Frank Raven ◽  
Elroy L Meijer ◽  
Martien JH Kas ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Memory Trace ◽  
Memory Loss ◽  
Pde4 Inhibitor ◽  
Loss Of Information ◽  
Phosphodiesterase 4 ◽  
Persistent Memory ◽  
Memory Engram ◽  
Actual Loss ◽  
Proof Of Principle

It is well established that sleep deprivation after learning impairs hippocampal memory processes and causes amnesia. It is unknown, however, whether it leads to the actual loss of information or merely suppresses the retrievability of this information stored under suboptimal conditions. Here, we reveal that hippocampal memories formed under sleep deprivation conditions can be successfully retrieved multiple days following training using optogenetic memory engram activation or treatment with the clinically-approved phosphodiesterase 4 (PDE4) inhibitor roflumilast. Moreover, when optogenetic memory engram activation and roflumilast treatment were combined two days following training and subsequent sleep deprivation, it resulted in a more persistent memory trace that allowed for natural (i.e., manipulation free) retrieval several days later. Our studies in mice demonstrate that sleep deprivation does not necessarily cause memory loss, but instead leads to the suboptimal storage of information that is difficult to retrieve. We also provide proof of principle that these suboptimally stored memories can be made accessible again far beyond the learning episode and that the clinically-approved PDE4 inhibitor roflumilast may be used to successfully retrieve information thought to be lost.

scholarly journals Pathology and Anticatalytic Treatment of Exacerbated COVID-19

2022 ◽  
Author(s):  
Jong-hoon Lee ◽  
Seongcheol Cho ◽  
Badar Kanwar ◽  
Keum-ho Lee ◽  
Tuan Ngoc Minh Nguyen ◽  
...  
Keyword(s):  
Spike Protein ◽  
Inflammasome Activation ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Genetic Pathway ◽  
Angiotensin Converting Enzyme 2 ◽  
Protein Levels ◽  
Neuropilin 1 ◽  
Immune Mediated ◽  
Memory Engram

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces immune-mediated inflammasome diseases. Moreover, its pathophysiology involves the angiotensin-converting enzyme 2 (ACE2) receptor, Toll-like receptor 4 (TLR4) pathway, neuropilin‑1 pathway, inflammasome activation pathway, sterile alpha motif (SAM) and histidine-aspartate domain (HD)-containing protein 1 (SAMHD1) tetramerization pathway, cytosolic DNA sensor cyclic-GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) signaling pathway, spike protein/inflammasome-genetic pathway, and immunological memory engram pathway. Therefore, it is necessary to prescribe anticatalytic treatments to alleviate the SARS-CoV-2 inflammasome, immunologic engram, and spike protein levels.

scholarly journals Brain-wide mapping of contextual fear memory engram ensembles supports the dispersed engram complex hypothesis

2019 ◽  
Author(s):  
Dheeraj S Roy ◽  
Young-Gyun Park ◽  
Sachie K Ogawa ◽  
Jae H Cho ◽  
Heejin Choi ◽  
...  
Keyword(s):  
High Probability ◽  
Fear Memory ◽  
Brain Regions ◽  
Memory Recall ◽  
Contextual Fear ◽  
Contextual Fear Memory ◽  
Neuronal Ensembles ◽  
Specific Memory ◽  
Complex Hypothesis ◽  
Memory Engram

Neuronal ensembles that hold specific memory (memory engrams) have been identified in the hippocampus, amygdala, and cortex. It has been hypothesized that engrams for a specific memory are distributed among multiple brain regions that are functionally connected. Here, we report the hitherto most extensive engram map for contextual fear memory by characterizing activity-tagged neurons in 409 regions using SHIELD-based tissue phenotyping. The mapping was aided by a novel engram index, which identified cFos+ brain regions holding engrams with a high probability. Optogenetic manipulations confirmed previously known engrams and revealed new engrams. Many of these engram holding-regions were functionally connected to the CA1 or amygdala engrams. Simultaneous chemogenetic reactivation of multiple engrams, which mimics natural memory recall, conferred a greater level of memory recall than reactivation of a single engram ensemble. Overall, our study supports the hypothesis that a memory is stored in functionally connected engrams distributed across multiple brain regions.

scholarly journals Orchestrated ensemble activities constitute a hippocampal memory engram

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Khaled Ghandour ◽  
Noriaki Ohkawa ◽  
Chi Chung Alan Fung ◽  
Hirotaka Asai ◽  
Yoshito Saitoh ◽  
...  
Keyword(s):  
Memory Engram
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