scholarly journals Dynamic Integrative Synaptic Plasticity Explains the Spacing Effect in the Transition from Short- to Long-Term Memory

2019 ◽  
Vol 31 (11) ◽  
pp. 2212-2251 ◽  
Author(s):  
Terry Elliott
Keyword(s):  
Synaptic Plasticity ◽  
Mapk Pathway ◽  
Spacing Effect ◽  
Long Term Memory ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Term Memory ◽  
Low Pass

Repeated stimuli that are spaced apart in time promote the transition from short- to long-term memory, while massing repetitions together does not. Previously, we showed that a model of integrative synaptic plasticity, in which plasticity induction signals are integrated by a low-pass filter before plasticity is expressed, gives rise to a natural timescale at which to repeat stimuli, hinting at a partial account of this spacing effect. The account was only partial because the important role of neuromodulation was not considered. We now show that by extending the model to allow dynamic integrative synaptic plasticity, the model permits synapses to robustly discriminate between spaced and massed repetition protocols, suppressing the response to massed stimuli while maintaining that to spaced stimuli. This is achieved by dynamically coupling the filter decay rate to neuromodulatory signaling in a very simple model of the signaling cascades downstream from cAMP production. In particular, the model's parameters may be interpreted as corresponding to the duration and amplitude of the waves of activity in the MAPK pathway. We identify choices of parameters and repetition times for stimuli in this model that optimize the ability of synapses to discriminate between spaced and massed repetition protocols. The model is very robust to reasonable changes around these optimal parameters and times, but for large changes in parameters, the model predicts that massed and spaced stimuli cannot be distinguished or that the responses to both patterns are suppressed. A model of dynamic integrative synaptic plasticity therefore explains the spacing effect under normal conditions and also predicts its breakdown under abnormal conditions.

scholarly journals Noise-Reducing Fabric Electrode for ECG Measurement

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4305
Author(s):  
Takamasa Terada ◽  
Masahiro Toyoura ◽  
Takahide Sato ◽  
Xiaoyang Mao
Keyword(s):  
Special Structure ◽  
Electrode Impedance ◽  
Electrode Structure ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Chip Type ◽  
Low Pass ◽  
Filter Fabric

In this work, we propose a fabric electrode with a special structure that can play the role of a noise reduction filter. Fabric electrodes made of the conductive fabric have been used for long-term ECG measurements because of their flexibility and non-invasiveness; however, due to the large impedance between the skin and the fabric electrodes, noise is easily introduced into the ECG signal. In contrast to conventional work, in which chip-type passive elements are glued to the electrode to reduce noise, the proposed electrode can obtain a noise-reduced ECG by changing the structure of fabric. Specifically, the proposed electrode was folded multiple times to form a capacitor with a capacitance of about 3 nF. It is combined with the skin-electrode impedance to form a low-pass filter. In the experiment, we made a prototype of the electrodes and measured ECG at rest and during EMG-induced exercise. As a result, the SNR values at rest and during exercise were improved about 12.02 and 10.29 , respectively, compared with the fabric electrode without special structure. In conclusion, we have shown that changing the fabric electrode structure effectively removes noise in ECG measurement.

Role of atypical protein kinases in maintenance of long-term memory and synaptic plasticity

2017 ◽  
Vol 82 (3) ◽  
pp. 243-256 ◽  
Author(s):  
A. A. Borodinova ◽  
A. B. Zuzina ◽  
P. M. Balaban
Keyword(s):  
Synaptic Plasticity ◽  
Protein Kinases ◽  
Long Term Memory ◽  
Term Memory

scholarly journals Reading Memory Formation from the Eyes

2018 ◽  
Author(s):  
Anne Bergt ◽  
Anne E. Urai ◽  
Tobias H. Donner ◽  
Lars Schwabe
Keyword(s):  
Synaptic Plasticity ◽  
Memory Formation ◽  
Pupil Dilation ◽  
Long Term Memory ◽  
Term Memory ◽  
Pupil Response ◽  
Rapid Formation ◽  
The Brain

At any time, we are processing thousands of stimuli, but only few of them will be remembered hours or days later. Is there any way to predict which ones? Here, we show that the pupil response to ongoing stimuli, an indicator of physiological arousal, is a reliable predictor of long-term memory for these stimuli, over at least one day. Pupil dilation was tracked while participants performed visual and auditory encoding tasks. Memory was tested immediately after encoding and 24 hours later. Irrespective of the encoding modality, trial-by-trial variations in pupil dilation predicted which stimuli were recalled in the immediate and 24 hours-delayed tests. These results show that our eyes may provide a window into the formation of long-term memories. Furthermore, our findings underline the important role of central arousal systems in the rapid formation of memories in the brain, possibly by gating synaptic plasticity mechanisms.

The role of PKMζ in the maintenance of long-term memory: a review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamish Patel ◽  
Reza Zamani
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Long Term Potentiation ◽  
Global Memory ◽  
Long Term Memory ◽  
Compensatory Mechanism ◽  
Term Memory ◽  
Kinase C

Abstract Long-term memories are thought to be stored in neurones and synapses that undergo physical changes, such as long-term potentiation (LTP), and these changes can be maintained for long periods of time. A candidate enzyme for the maintenance of LTP is protein kinase M zeta (PKMζ), a constitutively active protein kinase C isoform that is elevated during LTP and long-term memory maintenance. This paper reviews the evidence and controversies surrounding the role of PKMζ in the maintenance of long-term memory. PKMζ maintains synaptic potentiation by preventing AMPA receptor endocytosis and promoting stabilisation of dendritic spine growth. Inhibition of PKMζ, with zeta-inhibitory peptide (ZIP), can reverse LTP and impair established long-term memories. However, a deficit of memory retrieval cannot be ruled out. Furthermore, ZIP, and in high enough doses the control peptide scrambled ZIP, was recently shown to be neurotoxic, which may explain some of the effects of ZIP on memory impairment. PKMζ knockout mice show normal learning and memory. However, this is likely due to compensation by protein-kinase C iota/lambda (PKCι/λ), which is normally responsible for induction of LTP. It is not clear how, or if, this compensatory mechanism is activated under normal conditions. Future research should utilise inducible PKMζ knockdown in adult rodents to investigate whether PKMζ maintains memory in specific parts of the brain, or if it represents a global memory maintenance molecule. These insights may inform future therapeutic targets for disorders of memory loss.

scholarly journals HYPERMNESIA EUPHORIA OR ANY OTHER DESIRABLE FROM THE POINT OF VIEW OF THE CONSUMER, A PSYCHOTROPIC EFFECT - FIRST AND LEADING ELEMENT IN THE OCCURRENCE AND PRESERVATION OF THE BODY’S DEPENDENCE ON PSYCHOACTIVE FACTORS

2017 ◽  
Vol 9 (3) ◽  
pp. 40-46
Author(s):  
D G Baitubayev ◽  
M D Baitubayeva
Keyword(s):  
Substance Dependence ◽  
Point Of View ◽  
The Body ◽  
Long Term Memory ◽  
Vegetative Nervous System ◽  
Term Memory ◽  
Psychotropic Effect

The work shows the role of the vegetative nervous system (VNS) in the functioning of long-term memory, identity mechanisms of long-term memory in the human evolutionary adaptation and substance dependence. It is shown that, depending on the substance of the body are states like pro- gressive adaptation, that the bodycondition, depending on the chemical and psychogenic psychoactive- factors state of the same circle. It proposed the creation of a branch of medicine that combines study of the dependence of the organism, both on the chemical and psychoactive psychogenic factors. Given the classification of psychoactive factors.Onomastics formulated definitions of terminology changes and additions to be used in a new branch of medicine. Proposed allocation of the International Classifica- tion of diseases separate chapter for the classification of states like progressive adaptation of the body depending on psychoactive factors.

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