scholarly journals Soft-wired long-term memory in a natural recurrent neuronal network

2020 ◽  
Author(s):  
Miguel A. Casal ◽  
Santiago Galella ◽  
Oscar Vilarroya ◽  
Jordi Garcia-Ojalvo
Keyword(s):  
Neuronal Network ◽  
Neuronal Networks ◽  
Initial Conditions ◽  
Permutation Entropy ◽  
Long Term Memory ◽  
Term Memory ◽  
C Elegans ◽  
Living Organisms ◽  
Recurrent Connections

Neuronal networks provide living organisms with the ability to process information. They are also characterized by abundant recurrent connections, which give rise to strong feed-back that dictates their dynamics and endows them with fading (short-term) memory. The role of recurrence in long-term memory, on the other hand, is still unclear. Here we use the neuronal network of the roundworm C. elegans to show that recurrent architectures in living organisms can exhibit long-term memory without relying on specific hard-wired modules. A genetic algorithm reveals that the experimentally observed dynamics of the worm’s neuronal network exhibits maximal complexity (as measured by permutation entropy). In that complex regime, the response of the system to repeated presentations of a time-varying stimulus reveals a consistent behavior that can be interpreted as soft-wired long-term memory.A common manifestation of our ability to remember the past is the consistence of our responses to repeated presentations of stimuli across time. Complex chaotic dynamics is known to produce such reliable responses in spite of its characteristic sensitive dependence on initial conditions. In neuronal networks, complex behavior is known to result from a combination of (i) recurrent connections and (ii) a balance between excitation and inhibition. Here we show that those features concur in the neuronal network of a living organism, namely C. elegans. This enables long-term memory to arise in an on-line manner, without having to be hard-wired in the brain.

Caenorhabditis elegans Learning and Memory

2019 ◽  
Author(s):  
James S.H. Wong ◽  
Catharine H. Rankin
Keyword(s):  
Carbon Dioxide ◽  
Caenorhabditis Elegans ◽  
Classical Conditioning ◽  
Learning And Memory ◽  
Long Term Memory ◽  
Context Conditioning ◽  
Term Memory ◽  
C Elegans

The nematode, Caenorhabditis elegans (C. elegans), is an organism useful for the study of learning and memory at the molecular, cellular, neural circuitry, and behavioral levels. Its genetic tractability, transparency, connectome, and accessibility for in vivo cellular and molecular analyses are a few of the characteristics that make the organism such a powerful system for investigating mechanisms of learning and memory. It is able to learn and remember across many sensory modalities, including mechanosensation, chemosensation, thermosensation, oxygen sensing, and carbon dioxide sensing. C. elegans habituates to mechanosensory stimuli, and shows short-, intermediate-, and long-term memory, and context conditioning for mechanosensory habituation. The organism also displays chemotaxis to various chemicals, such as diacetyl and sodium chloride. This behavior is associated with several forms of learning, including state-dependent learning, classical conditioning, and aversive learning. C. elegans also shows thermotactic learning in which it learns to associate a particular temperature with the presence or absence of food. In addition, both oxygen preference and carbon dioxide avoidance in C. elegans can be altered by experience, indicating that they have memory for the oxygen or carbon dioxide environment they were reared in. Many of the genes found to underlie learning and memory in C. elegans are homologous to genes involved in learning and memory in mammals; two examples are crh-1, which is the C. elegans homolog of the cAMP response element-binding protein (CREB), and glr-1, which encodes an AMPA glutamate receptor subunit. Both of these genes are involved in long-term memory for tap habituation, context conditioning in tap habituation, and chemosensory classical conditioning. C. elegans offers the advantage of having a very small nervous system (302 neurons), thus it is possible to understand what these conserved genes are doing at the level of single identified neurons. As many mechanisms of learning and memory in C. elegans appear to be similar in more complex organisms including humans, research with C. elegans aids our ever-growing understanding of the fundamental mechanisms of learning and memory across the animal kingdom.

scholarly journals Soft-wired long-term memory in a natural recurrent neuronal network

2020 ◽  
Vol 30 (6) ◽  
pp. 061101
Author(s):  
Miguel A. Casal ◽  
Santiago Galella ◽  
Oscar Vilarroya ◽  
Jordi Garcia-Ojalvo
Keyword(s):  
Neuronal Network ◽  
Long Term Memory ◽  
Term Memory ◽  
Recurrent Neuronal Network

Olfactory Associative Discrimination: A Model for Studying Modifications of Synaptic Efficacy in Neuronal Networks Supporting Long-term Memory

2004 ◽  
Vol 15 (1) ◽  
pp. 1-18 ◽  
Author(s):  
François S. Roman ◽  
Bruno Truchet ◽  
Franck A. Chaillan ◽  
Evelyne Marchetti ◽  
Bernard Soumireu-Mourat
Keyword(s):  
Neuronal Networks ◽  
Long Term Memory ◽  
Synaptic Efficacy ◽  
Term Memory

scholarly journals Actin Cytoskeleton Role in the Maintenance of Neuronal Morphology and Long-Term Memory

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1795
Author(s):  
Raphael Lamprecht
Keyword(s):  
Actin Cytoskeleton ◽  
Neuronal Network ◽  
Morphological Changes ◽  
Neuronal Morphology ◽  
Regulatory Proteins ◽  
Long Term Memory ◽  
Term Memory ◽  
Actin Regulatory Proteins ◽  
Spine Structure

Evidence indicates that long-term memory formation creates long-lasting changes in neuronal morphology within a specific neuronal network that forms the memory trace. Dendritic spines, which include most of the excitatory synapses in excitatory neurons, are formed or eliminated by learning. These changes may be long-lasting and correlate with memory strength. Moreover, learning-induced changes in the morphology of existing spines can also contribute to the formation of the neuronal network that underlies memory. Altering spines morphology after memory consolidation can erase memory. These observations strongly suggest that learning-induced spines modifications can constitute the changes in synaptic connectivity within the neuronal network that form memory and that stabilization of this network maintains long-term memory. The formation and elimination of spines and other finer morphological changes in spines are mediated by the actin cytoskeleton. The actin cytoskeleton forms networks within the spine that support its structure. Therefore, it is believed that the actin cytoskeleton mediates spine morphogenesis induced by learning. Any long-lasting changes in the spine morphology induced by learning require the preservation of the spine actin cytoskeleton network to support and stabilize the spine new structure. However, the actin cytoskeleton is highly dynamic, and the turnover of actin and its regulatory proteins that determine and support the actin cytoskeleton network structure is relatively fast. Molecular models, suggested here, describe ways to overcome the dynamic nature of the actin cytoskeleton and the fast protein turnover and to support an enduring actin cytoskeleton network within the spines, spines stability and long-term memory. These models are based on long-lasting changes in actin regulatory proteins concentrations within the spine or the formation of a long-lasting scaffold and the ability for its recurring rebuilding within the spine. The persistence of the actin cytoskeleton network within the spine is suggested to support long-lasting spine structure and the maintenance of long-term memory.

Long-term memory genes in C. elegans

2015 ◽  
Vol 47 (3) ◽  
pp. 198-198
Author(s):  
Brooke LaFlamme
Keyword(s):  
Long Term Memory ◽  
Term Memory ◽  
C Elegans

scholarly journals Sleep is required for odor exposure to consolidate memory and remodel synapses

2020 ◽  
Author(s):  
Fernando Muñoz-Lobato ◽  
Kelli L. Benedetti ◽  
Fatima Farah ◽  
Rashmi Chandra ◽  
Anirudh Bokka ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Living Organism ◽  
Long Term Memory ◽  
Synaptic Connections ◽  
Term Memory ◽  
C Elegans ◽  
Seeking Behavior ◽  
Synaptic Changes ◽  
Odor Exposure

SummarySleep is conserved across phyla and is shown here to be required for memory consolidation in the nematode, C. elegans. However, it is unclear how sleep collaborates with experience to change specific neurons and associated synapses to ultimately affect behavior. C. elegans neurons have defined synaptic connections and described contributions to specific behaviors. We show that spaced odor-training induces long-term memory, which transits a labile period before being stably maintained. This post-training labile period is required for long-term memory. Memory consolidation, but not acquisition, requires a single interneuron, AIY, which plays a role in odor-seeking behavior. We find that sleep and conditioning mark inhibitory synaptic connections between the butanone-sensing AWC neuron and AIY to decrease synapses and it is in the post-sleep wake phase that memory-specific synaptic changes occur. Thus, we demonstrate in the living organism how sleep initiates events lasting beyond the period of sleep to drive memory consolidation.

scholarly journals Differential regulation of native and learned behavior by creb-1/crh-1 in Caenorhabditis elegans

2019 ◽  
Author(s):  
Yogesh Dahiya ◽  
Saloni Rose ◽  
Shruti Thapliyal ◽  
Shivam Bhardwaj ◽  
Maruthi Prasad ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Memory Formation ◽  
Long Term Memory ◽  
Null Mutant ◽  
Term Memory ◽  
Learned Behavior ◽  
C Elegans ◽  
Insight Into ◽  
Null Mutants

1.AbstractMemory formation is crucial for the survival of animals. Here, we study the effect of different crh-1 (C. elegans homolog of mammalian CREB1) mutations on the ability of C. elegans to form long-term memory (LTM). Null mutants in creb1/crh-1 are defective in LTM formation across phyla. We show that specific isoforms of CREB1/CRH-1, CRH-1c and CRH-1e, are primarily responsible for memory related functions of the transcription factor in C. elegans. Silencing of CRH-1e expressing neurons during training for LTM formation abolishes the long-term memory of the animal. Further, CRH-1e expression in RIM or AVE neurons is sufficient to rescue long-term memory defects of creb1/crh-1 null mutants. We show that apart from being LTM defective, creb1/crh-1 null mutant animals show defects in native chemotaxis behavior. We characterize the amino acids K247 and K266 as responsible for the LTM related functions of CRH-1 while being dispensable for it’s native chemotaxis behavior. These findings provide insight into the spatial and temporal workings of a crucial transcription factor and can be further exploited to find CREB1 targets involved in the process of memory formation.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

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