scholarly journals Dynamical modulation of theta-gamma coupling during REM sleep

2017 ◽  
Author(s):  
Mojtaba Bandarabadi ◽  
Richard Boyce ◽  
Carolina Gutierrez Herrera ◽  
Claudio Bassetti ◽  
Sylvain Williams ◽  
...  
Keyword(s):  
Theta Rhythm ◽  
Underlying Mechanism ◽  
Phase Coherence ◽  
Long Term Memory ◽  
Rapid Eye Movement Sleep ◽  
Hippocampal Ca3 ◽  
Theta Phase ◽  
Space Coding ◽  
Specific Phase

Theta phase modulates gamma amplitude during spatial navigation and rapid eye movement sleep (REMs). Although the REMs theta rhythm has been linked to spatial memory consolidation, the underlying mechanism remains unclear. We investigate dynamics of theta-gamma interactions across multiple frequency and temporal scales in simultaneous recordings from hippocampal CA3, CA1, subiculum, and parietal cortex. We show that theta phase significantly modulates three distinct gamma bands during REMs, dynamically. Interestingly, we further show that theta-gamma coupling swings between different hippocampal and cortical structures during REMs and tends to increase over a single REMs episode. Comparing to active wake, theta-gamma coupling during REMs is significantly increased for subicular and cortical, but not for CA3 and CA1, recordings. Finally, optogenetic silencing of septohippocampal GABAergic projections significantly impedes both theta-gamma coupling and theta phase coherence, two neural mechanisms of working and long-term memory, respectively. Thus, we show that theta-gamma coupling and theta phase coherence are highly modulated during single REMs episode and propose that theta-gamma coupling provides a predominant mechanism for information processing within each brain region, while the orchestrated nature of coupling activity establishes a specific phase-space coding of information during sleep.

β1-and β2-adrenoceptors in hippocampal CA3 region are required for long-term memory consolidation in rats

2015 ◽  
Vol 1627 ◽  
pp. 109-118 ◽  
Author(s):  
Jian Zheng ◽  
Fei Luo ◽  
Nan-nan Guo ◽  
Zong-yue Cheng ◽  
Bao-ming Li
Keyword(s):  
Memory Consolidation ◽  
Long Term Memory ◽  
Term Memory ◽  
Hippocampal Ca3 ◽  
Ca3 Region

scholarly journals Neurofeedback Training Improves Long-Term Memory Performance

2021 ◽  
Author(s):  
Yu-Hsuan Tseng ◽  
Kaori Tamura ◽  
Tsuyoshi Okamoto
Keyword(s):  
Semantic Memory ◽  
Theta Rhythm ◽  
Brain Activity ◽  
Human Life ◽  
Memory Performance ◽  
Control Group ◽  
Long Term Memory ◽  
Term Memory ◽  
Beta Power

Abstract Understanding and improving memory is vital to enhance human life. Theta rhythm is associated with memory consolidation and coding, but the trainability and effects on long-term memory of theta rhythm are unknown. This study investigates the ability to improve long-term memory using a neurofeedback (NFB) technique reflecting the theta/low-beta power ratio on an electroencephalogram (EEG). Our study consisted of three stages: First, the long-term memory of participants was measured. In the second stage, the participants in the NFB group received three days of theta/low-beta NFB training. In the third stage, the long-term memory was measured again. The NFB group had better long-term memory than the control group and significant differences in brain activity between episodic and semantic memory during the recall tests were revealed. These findings suggest that it is possible to improve the long-term memory abilities through theta/low-beta NFB training, which also improves episodic and semantic memory.

scholarly journals Mechanisms of Human intelligence — From RNA and Synapse to Broadband

2019 ◽  
Author(s):  
Robert Traill
Keyword(s):  
Underlying Mechanism ◽  
Long Term Memory ◽  
Optical Signals ◽  
A Cell ◽  
Impossible Task ◽  
The Many ◽  
The Right ◽  
Label Sequence

Simple thought has been explained by the action-potential (AP) system with its synapses. In contrast, in-depth details for “Declarative” intellectual thought have been a complete mystery because (it is argued here) its main underlying mechanism is fundamentally different. Declarative thinking depends heavily on linear coding based on digit-like elements — something which an unaided AP system could never offer......Looking instead to psychology, Piaget (1920s) proposed basic units of action-sequences (“schèmes” whereby one could mentally construct object-concepts). There is now evidence that some ncRNA serves this verb-like action-coding role. — (Other ncRNA demonstrably serves as adjectival/adverbial “regulators” — while the remaining ≈3% of RNA encodes physical structures, the traditional noun-like role). If valid, then:–•NEW FOCUS ONTO ULTRAMICRO: — The whole Piagetian structure-coding for a concept could fit into one of the many 125nm capsids (“granules”). Moreover, many more concepts (and duplicates) could fit into a cell-body. — The vast abundance of coding-sites would allow comprehensive “wasteful” rapid use of Jerneian/Darwinian selection instead of problematic “writing down” of new learnings. — Estimates of memory-capacity increase vastly. — And hereditary-schèmes obviously explain inherited behaviour-traits. — Piaget’s other theory about develop¬mental stages also seems compatible.•Quantum-constraints ensure that such micro-sites would USE OPTICAL FREQUENCY signalling. That opens the way to greatly enhanced “Gigabit” rates, and optical-interference tricks.•MYELIN gets the EXTRA ROLE OF OPTIC-CABLE.So nerve-fibres become seen as simultan¬eous paths for two different types of signal (also demonstrated by Sun-et-al, 2010), with AP still dominant in some roles, but subservient to “UPE” optical signals elsewhere.•LOCATING MEMORIES? Choosing the right address means selecting some sort of “phone-number or numbered plug-socket.” That is best provided as an “address-label” sequence on the transmitted version of the schème-coding — in which case, actual destination-location may be less important.•“Moving-house” TO CORTICAL LONG-TERM MEMORY. The memory-move must preserve existing (i) memory-structure, and (ii) links to distant static archives. This “impossible” task would seem feasible if memories are actually held within individual cells (as above). There is indeed lifelong flow of such neurons in some mammals; but these flows seem to cease in adulthood for humans and dolphins! So the search continues.

scholarly journals RNG105/caprin1, an RNA granule protein for dendritic mRNA localization, is essential for long-term memory formation

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Kei Nakayama ◽  
Rie Ohashi ◽  
Yo Shinoda ◽  
Maya Yamazaki ◽  
Manabu Abe ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Underlying Mechanism ◽  
Surface Expression ◽  
Mrna Localization ◽  
Synaptic Strength ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Dendritic Mrna

Local regulation of synaptic efficacy is thought to be important for proper networking of neurons and memory formation. Dysregulation of global translation influences long-term memory in mice, but the relevance of the regulation specific for local translation by RNA granules remains elusive. Here, we demonstrate roles of RNG105/caprin1 in long-term memory formation. RNG105 deletion in mice impaired synaptic strength and structural plasticity in hippocampal neurons. Furthermore, RNG105-deficient mice displayed unprecedentedly severe defects in long-term memory formation in spatial and contextual learning tasks. Genome-wide profiling of mRNA distribution in the hippocampus revealed an underlying mechanism: RNG105 deficiency impaired the asymmetric somato-dendritic localization of mRNAs. Particularly, RNG105 deficiency reduced the dendritic localization of mRNAs encoding regulators of AMPAR surface expression, which was consistent with attenuated homeostatic AMPAR scaling in dendrites and reduced synaptic strength. Thus, RNG105 has an essential role, as a key regulator of dendritic mRNA localization, in long-term memory formation.

scholarly journals Engram reactivation during memory retrieval predicts long-term memory performance in aged mice

2020 ◽  
Author(s):  
Kubra Gulmez Karaca ◽  
David V.C. Brito ◽  
Benjamin Zeuch ◽  
Ana M.M. Oliveira
Keyword(s):  
Cognitive Decline ◽  
Memory Performance ◽  
Underlying Mechanism ◽  
Long Term Memory ◽  
Memory Recall ◽  
Term Memory ◽  
Aged Mice ◽  
Neuronal Ensembles ◽  
Age Related

AbstractAge-related cognitive decline preferentially targets long-lasting episodic memories that require intact hippocampal function. Memory traces (or engrams) are believed to be encoded within the neurons activated during learning (neuronal ensembles), and recalled by reactivation of the same population. However, whether engram reactivation dictates memory performance in late life is not known. Here, we labelled neuronal ensembles formed during object location recognition learning in the dentate gyrus, and analyzed the reactivation of this population by long-term memory recall in young adult, cognitively impaired- and unimpaired-aged mice. We found that reactivation of memory-encoding neuronal ensembles at long-term memory recall was disrupted in impaired- but not unimpaired-aged mice. Furthermore, we showed that the memory performance in the aged population correlated with the degree of engram reactivation at long-term memory recall. Overall, our data implicates recall-induced engram reactivation as a prediction factor of memory performance throughout aging. Moreover, our findings suggest impairments in neuronal ensemble stabilization and/or reactivation as an underlying mechanism in age-dependent cognitive decline.

scholarly journals Interaction between theta-phase and spike-timing dependent plasticity simulates theta induced memory effects

2021 ◽  
Author(s):  
Danying Wang ◽  
George Michael Parish ◽  
Kimron L Shapiro ◽  
Simon Hanslmayr
Keyword(s):  
Episodic Memory ◽  
Theta Rhythm ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
Spike Timing Dependent Plasticity ◽  
Cell Culture Study ◽  
Dependent Plasticity ◽  
Hippocampal Cell Culture ◽  
Theta Phase

Rodent studies suggest that spike timing relative to hippocampal theta activity determines whether potentiation or depression of synapses arise. Such changes also depend on spike timing between pre- and post-synaptic neurons, known as spike-timing-dependent plasticity (STDP). STDP, together with theta-phase-dependent learning, has inspired several computational models of learning and memory. However, evidence to elucidate how these mechanisms directly link to human episodic memory is lacking. In a computational model, we modulate long-term potentiation (LTP) and long-term depression (LTD) of STDP, by opposing phases of a simulated theta rhythm. We fit parameters to a hippocampal cell culture study in which LTP and LTD were observed to occur in opposing phases of a theta rhythm. Further, we modulated two inputs by cosine waves with synchronous and asynchronous phase offsets and replicate key findings in human episodic memory. Learning advantage was found for the synchronous condition, as compared to the asynchronous conditions, and was specific to theta modulated inputs. Importantly, simulations with and without each mechanism suggest that both STDP and theta-phase-dependent plasticity are necessary to replicate the findings. Together, the results indicate a role for circuit-level mechanisms, which bridges the gap between slice preparation studies and human memory.

Manipulation of hippocampal CA3 firing via luminopsins modulates spatial and episodic short-term memory, especially working memory, but not long-term memory

2018 ◽  
Vol 155 ◽  
pp. 435-445 ◽  
Author(s):  
Da Song ◽  
Qinghu Yang ◽  
Yiran Lang ◽  
Zhaosen Wen ◽  
Zhen Xie ◽  
...  
Keyword(s):  
Working Memory ◽  
Short Term Memory ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Hippocampal Ca3

Working Memory Mediates the Relationship between Intellectual Enrichment and Long-Term Memory in Multiple Sclerosis: An Exploratory Analysis of Cognitive Reserve

2014 ◽  
Vol 20 (8) ◽  
pp. 868-872 ◽  
Author(s):  
Joshua Sandry ◽  
James F. Sumowski
Keyword(s):  
Multiple Sclerosis ◽  
Working Memory ◽  
Cognitive Reserve ◽  
Digit Span ◽  
Verbal Learning ◽  
Underlying Mechanism ◽  
Long Term Memory ◽  
Term Memory ◽  
The Relationship

AbstractSome individuals with multiple sclerosis (MS) show decrements in long-term memory (LTM) while other individuals do not. The theory of cognitive reserve suggests that individuals with greater pre-morbid intellectual enrichment are protected from disease-related cognitive decline. How intellectual enrichment affords this benefit remains poorly understood. The present study tested an exploratory meditational hypothesis whereby working memory (WM) capacity may mediate the relationship between intellectual enrichment and verbal LTM decline in MS. Intellectual enrichment, verbal LTM, and WM capacity were estimated with the Wechsler Test of Adult Reading and Peabody Picture Vocabulary Test, delayed recall of the Hopkins Verbal Learning Test-Revised and Logical Memory of the Wechsler Memory Scale, and Digit Span Total, respectively. Intellectual enrichment predicted LTM (B=.54;p=.003) and predicted WM capacity (B=.91;p<.001). WM capacity predicted LTM, (B=.44;p<.001) and fully mediated the relationship between intellectual enrichment (B=.24;p=.27) and LTM (B=.33,p=.03), Sobel test,Z=3.31,p<.001. These findings implicate WM capacity as an underlying mechanism of cognitive reserve and are an initial first step in understanding the relationship between intellectual enrichment, WM, and LTM in MS. (JINS, 2014,20, 1–5)

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