Restitution and adaptation measurements for the estimate of short-term cardiac action potential memory: comparison of five human ventricular models

Abstract Aims This computational study refines our recently published pacing protocol to measure short-term memory (STM) of cardiac action potential (AP), and apply it to five numerical models of human ventricular AP. Methods and results Several formulations of electrical restitution (ER) have been provided over the years, including standard, beat-to-beat, dynamic, steady-state, which make it difficult to compare results from different studies. We discuss here the notion of dynamic ER (dER) by relating it to its steady-state counterpart, and propose a pacing protocol based on dER to measure STM under periodically varying pacing cycle length (CL). Under high and highly variable-pacing rate, all models develop STM, which can be measured over the entire sequence by means of dER. Short-term memory can also be measured on a beat-to-beat basis by estimating action potential duration (APD) adaptation after clamping CL constant. We visualize STM as a phase shift between action potential (AP) parameters over consecutive cycles of CL oscillations, and show that delay between CL and APD oscillation is nearly constant (around 92 ms) in the five models, despite variability in their intrinsic AP properties. Conclusion dER, as we define it and together with other approaches described in the study, provides an univocal way to measure STM under extreme cardiac pacing conditions. Given the relevance of AP memory for repolarization dynamics and stability, STM should be considered, among other usual biomarkers, to validate and tune cardiac AP models. The possibility of extending the method to in vivo cellular and whole organ models can also be profitably explored.

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A protocol combining current- and voltage-clamp provides a novel and useful three-dimensional representation of cardiac action potential

Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale ◽

10.4081/jbr.2014.2134 ◽

2014 ◽

Vol 87 (1) ◽

Author(s):

Massimiliano Zaniboni ◽

Francesca Cacciani

Keyword(s):

Action Potential ◽

Current Source ◽

Three Dimensional ◽

Membrane Conductance ◽

Ventricular Repolarization ◽

Cardiac Action Potential ◽

Dimensional Representation ◽

Cardiac Action ◽

Three Dimensional Representation

A compact three-dimensional representation of cardiac action potential (AP) properties in terms of current source is presented here. The experimental protocol used to obtain such representation is based on the measure of instantaneous current-voltage relationships during the course of the AP. The procedure, which combines current- and voltage-clamps on patch clamped cardiac myocytes, has been previously applied to real cells, and then extended to computer simulations with cellular ventricular AP models. The three-dimensional AP representation allows to easily estimate membrane resistance during repolarization, a key factor for the modulation of ventricular repolarization. It also shows that, during late ventricular repolarization, membrane conductance becomes negative, <em>i.e.</em> repolarization is auto-regenerative. The novel AP representation is therefore a useful tool for both in vivo and in silico cardiac cellular electrophysiological investigations.

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EFFECTS OF INWARD/OUTWARD CURRENT INJECTION AT THE EARLY PLATEAU PHASE ON CARDIAC ACTION POTENTIAL DURATIONS: A COMPUTATIONAL STUDY

Advances in Electrocardiology 2004 ◽

10.1142/9789812702234_0024 ◽

2005 ◽

Author(s):

YUJI HIRANO ◽

MASAYASU HIRAOKA

Keyword(s):

Action Potential ◽

Computational Study ◽

Outward Current ◽

Current Injection ◽

Cardiac Action Potential ◽

Plateau Phase ◽

Cardiac Action

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Change of short-term memory effect in acute ischemic ventricular myocardium: A computational study

Computer Methods and Programs in Biomedicine ◽

10.1016/j.cmpb.2013.11.007 ◽

2014 ◽

Vol 113 (2) ◽

pp. 690-696

Author(s):

Xi Mei ◽

Jing Wang ◽

Hong Zhang ◽

Zhi-cheng Liu ◽

Zhen-xi Zhang

Keyword(s):

Memory Effect ◽

Short Term Memory ◽

Computational Study ◽

Ventricular Myocardium ◽

Short Term ◽

Term Memory

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Deep brain stimulation facilitates memory in a model of Alzheimer’s disease

Translational Neuroscience ◽

10.2478/v10134-010-0026-7 ◽

2010 ◽

Vol 1 (2) ◽

Cited By ~ 1

Author(s):

Isabel Arrieta-Cruz ◽

Constantine Pavlides ◽

Giulio Pasinetti

Keyword(s):

Short Term Memory ◽

Hippocampal Slices ◽

In Vivo Studies ◽

Short Term ◽

Term Memory ◽

Ca1 Region ◽

Secretase Activity ◽

Tgcrnd8 Mice ◽

Deep Brain

AbstractBased on evidence suggesting that deep brain stimulation (DBS) may promote certain cognitive processes, we have been interested in developing DBS as a means of mitigating memory and learning impairments in Alzheimer’s disease (AD). In this study we used an animal model of AD (TgCRND8 mice) to determine the effects of high-frequency stimulation (HFS) on non-amyloidogenic α-secretase activity and DBS in short-term memory. We tested our hypothesis using hippocampal slices (in vitro studies) from TgCRND8 mice to evaluate whether HFS increases α-secretase activity (non-amyloidogenic pathway) in the CA1 region. In a second set of experiments, we performed in vivo studies to evaluate whether DBS in midline thalamic region re-establishes hippocampal dependent short-term memory in TgCRND8 mice. The results showed that application of HFS to isolated hippocampal slices significantly increased synaptic plasticity in the CA1 region and promoted a 2-fold increase of non-amyloidogenic α-secretase activity, in comparison to low frequency stimulated controls from TgCRND8 mice. In the in vivo studies, DBS treatment facilitated acquisition memory in TgCRND8 mice, in comparison to their own baseline before treatment. These results provide evidence that DBS could enhance short-term memory in a mouse model of AD by increasing synaptic transmission and α-secretase activity in the CA1 region of hippocampus.

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7-O-Esters of taxifolin with pronounced and overadditive effects in neuroprotection, anti-neuroinflammation, and amelioration of short-term memory impairment in vivo

Redox Biology ◽

10.1016/j.redox.2019.101378 ◽

2020 ◽

Vol 29 ◽

pp. 101378 ◽

Cited By ~ 4

Author(s):

Sandra Gunesch ◽

Matthias Hoffmann ◽

Carolina Kiermeier ◽

Wolfgang Fischer ◽

Antonio F.M. Pinto ◽

...

Keyword(s):

Memory Impairment ◽

Short Term Memory ◽

Short Term ◽

Term Memory

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A proposed algorithm based on long short-term memory network and gradient boosting for aeroengine thrust estimation on transition state

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410021993303 ◽

2021 ◽

pp. 095441002199330

Author(s):

Yong-Ping Zhao ◽

Yao-Bin Chen ◽

Zhi-Qiang Li

Keyword(s):

Steady State ◽

Transition State ◽

Short Term Memory ◽

Gradient Boosting ◽

Short Term ◽

Term Memory ◽

Memory Network ◽

Long Short Term Memory ◽

Direct Thrust Control ◽

Almost All

Aeroengine thrust estimation is an important problem for direct thrust control since it is unmeasurable. Many methods and algorithms have been proposed to solve this problem. Unfortunately, almost all these methods can only estimate aeroengine thrust when the engine is in steady state. Hence, this study proposes an algorithm based on long short-term memory networks and gradient boosting for aeroengine thrust estimation in transition state. The newly proposed algorithm can estimate thrust of an aeroengine when its working state is changed from one steady state to another. The experimental results demonstrated that the proposed algorithm can be well applied to estimate aeroengine thrust in transition state and the estimated precision can meet the requirements of thrust estimation.

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A Single Brief Burst Induces GluR1-dependent Associative Short-term Potentiation: A Potential Mechanism for Short-term Memory

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2009.21375 ◽

2010 ◽

Vol 22 (11) ◽

pp. 2530-2540 ◽

Cited By ~ 65

Author(s):

Martha A. Erickson ◽

Lauren A. Maramara ◽

John Lisman

Keyword(s):

Knockout Mice ◽

Short Term Memory ◽

Long Term Potentiation ◽

Dual Process ◽

Short Term ◽

Model Learning ◽

Term Memory ◽

Term Potentiation

Recent work showed that short-term memory (STM) is selectively reduced in GluR1 knockout mice. This raises the possibility that a form of synaptic modification dependent on GluR1 might underlie STM. Studies of synaptic plasticity have shown that stimuli too weak to induce long-term potentiation induce short-term potentiation (STP), a phenomenon that has received little attention. Here we examined several properties of STP and tested the dependence of STP on GluR1. The minimal requirement for inducing STP was examined using a test pathway and a conditioning pathway. Several closely spaced stimuli in the test pathway, forming a single brief burst, were sufficient to induce STP. Thus, STP is likely to be induced by the similar bursts that occur in vivo. STP induction is associative in nature and dependent on the NMDAR. STP decays with two components, a fast component (1.6 ± 0.26 min) and a slower one (19 ± 6.6 min). To test the role of GluR1 in STP, experiments were conducted on GluR1 knockout mice. We found that STP was greatly reduced. These results, taken together with the behavioral work of D. Sanderson et al. [Sanderson, D., Good, M. A., Skelton, K., Sprengel, R., Seeburg, P. H., Nicholas, J., et al. Enhanced long-term and impaired short-term spatial memory in GluA1 AMPA receptor subunit knockout mice: Evidence for a dual-process memory model. Learning and Memory, 2009], provide genetic evidence that STP is a likely mechanism of STM.

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Analysis of Meteorological Factor Multivariate Models for Medium- and Long-Term Photovoltaic Solar Power Forecasting Using Long Short-Term Memory

Applied Sciences ◽

10.3390/app11010316 ◽

2020 ◽

Vol 11 (1) ◽

pp. 316

Author(s):

Namrye Son ◽

Mina Jung

Keyword(s):

Wind Speed ◽

Solar Radiation ◽

Cloud Cover ◽

Solar Power ◽

Short Term Memory ◽

Numerical Models ◽

Short Term ◽

Term Memory ◽

Long Short Term Memory

Solar power generation is an increasingly popular renewable energy topic. Photovoltaic (PV) systems are installed on buildings to efficiently manage energy production and consumption. Because of its physical properties, electrical energy is produced and consumed simultaneously; therefore solar energy must be predicted accurately to maintain a stable power supply. To develop an efficient energy management system (EMS), 22 multivariate numerical models were constructed by combining solar radiation, sunlight, humidity, temperature, cloud cover, and wind speed. The performance of the models was compared by applying a modified version of the traditional long short-term memory (LSTM) approach. The experimental results showed that the six meteorological factors influence the solar power forecast regardless of the season. These are, from most to least important: solar radiation, sunlight, wind speed, temperature, cloud cover, and humidity. The models are rated for suitability to provide medium- and long-term solar power forecasts, and the modified LSTM demonstrates better performance than the traditional LSTM.

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A β-secretase modulator decreases Tau pathology and preserves short-term memory in a mouse model of neurofibrillary degeneration

10.1101/2021.04.02.438175 ◽

2021 ◽

Author(s):

Marie Tautou ◽

Sabiha Eddarkaoui ◽

Florian Descamps ◽

Paul-Emmanuel Larchanche ◽

Melanie Dumoulin ◽

...

Keyword(s):

Nitrogen Atom ◽

Mouse Model ◽

Short Term Memory ◽

Tau Pathology ◽

Short Term ◽

Term Memory ◽

Transgenic Model ◽

Structure Activity ◽

Inflammatory Processes

A structure-activity relationship has enabled us to identify two molecules, MAGS02-14 and PEL24-199, sharing a β-secretase modulatory effect but having or not a lysosomotropic activity, respectively. More importantly, MAGS02-14 and PEL24-199 only differ from each other by a single nitrogen atom. However, which of the lysosomotropic and/or β-secretase modulating activities is necessary for the pharmacological effect in vivo remains ill-defined. To address this question, the THY-Tau22 transgenic model of NFD was treated for 6 weeks in a curative paradigm and short-term memory, Tau burden, and inflammatory processes were studied. PEL24-199, possessing only the β-secretase modulatory activity, was shown to restore the short-term memory and to reduce NFD. This effect was associated with reduced phosphorylation of Tau, increased phosphatase expression, and a decrease of astrogliosis. Our results, therefore, suggest that the lysosomotropic activity may be dispensable for the effect on both Aβ and Tau pathologies.

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