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Neuroscience Apr 2021Perceiving the temporal regularity in a sequence of repetitive sensory events facilitates the preparation and execution of relevant behaviors with tight temporal...
Perceiving the temporal regularity in a sequence of repetitive sensory events facilitates the preparation and execution of relevant behaviors with tight temporal constraints. How we estimate temporal regularity from repeating patterns of sensory stimuli is not completely understood. We developed a decision-making task in which participants had to decide whether a train of visual, auditory, or tactile pulses, had a regular or an irregular temporal pattern. We tested the hypothesis that subjects categorize stimuli as irregular by accumulating the time differences between the predicted and observed times of sensory pulses defining a temporal rhythm. Results suggest that instead of waiting for a single large temporal deviation, participants accumulate timing-error signals and judge a pattern as irregular when the amount of evidence reaches a decision threshold. Model fits of bounded integration showed that this accumulation occurs with negligible leak of evidence. Consistent with previous findings, we show that participants perform better when evaluating the regularity of auditory pulses, as compared with visual or tactile stimuli. Our results suggest that temporal regularity is estimated by comparing expected and measured pulse onset times, and that each prediction error is accumulated towards a threshold to generate a behavioral choice.
Topics: Auditory Perception; Humans; Touch
PubMed: 33549694
DOI: 10.1016/j.neuroscience.2021.01.035 -
Journal of General Internal Medicine Jan 2022Palpitations are a common symptom managed by general practitioners and cardiologists; atrial fibrillation (AF) is the most common arrhythmia in adults. The recent... (Review)
Review
Palpitations are a common symptom managed by general practitioners and cardiologists; atrial fibrillation (AF) is the most common arrhythmia in adults. The recent commercial availability of smartphone-based devices and wearable technologies with arrhythmia detection capabilities has revolutionized the diagnosis and management of these common medical issues, as it has placed the power of arrhythmia detection into the hands of the patient. Numerous mobile health (mHealth) devices that can detect, record, and automatically interpret irregularities in heart rhythm and abrupt changes in heart rate using photoplethysmography (PPG)- and electrocardiogram-based technologies are now commercially available. As opposed to prescription-based external rhythm monitoring approaches, these devices are more inexpensive and allow for longer-term monitoring, thus increasing sensitivity for arrhythmia detection, particularly for patients with infrequent symptoms possibly due to cardiac arrhythmias. These devices can be used to correlate symptoms with cardiac arrhythmias, assess efficacy and toxicities of arrhythmia therapies, and screen the population for serious rhythm disturbances such as AF. Although several devices have received clearance for AF detection from the United States Food & Drug Administration, limitations include the need for ECG confirmation for arrhythmias detected by PPG alone, false positives, false negatives, charging requirements for the battery, and financial cost. In summary, the growth of commercially available devices for remote, patient-facing rhythm monitoring represents an exciting new opportunity in the care of patients with palpitations and known or suspected dysrhythmias. Physicians should be familiar with the evidence that underlies their added value to patient care and, importantly, their current limitations.
Topics: Adult; Atrial Fibrillation; Electrocardiography; Humans; Photoplethysmography; Smartphone; Telemedicine
PubMed: 34282532
DOI: 10.1007/s11606-021-07007-w -
Computational Intelligence and... 2022One of the most challenging tasks for clinicians is detecting symptoms of cardiovascular disease as earlier as possible. Many individuals worldwide die each year from...
One of the most challenging tasks for clinicians is detecting symptoms of cardiovascular disease as earlier as possible. Many individuals worldwide die each year from cardiovascular disease. Since heart disease is a major concern, it must be dealt with timely. Multiple variables affecting health, such as excessive blood pressure, elevated cholesterol, an irregular pulse rate, and many more, make it challenging to diagnose cardiac disease. Thus, artificial intelligence can be useful in identifying and treating diseases early on. This paper proposes an ensemble-based approach that uses machine learning (ML) and deep learning (DL) models to predict a person's likelihood of developing cardiovascular disease. We employ six classification algorithms to predict cardiovascular disease. Models are trained using a publicly available dataset of cardiovascular disease cases. We use random forest (RF) to extract important cardiovascular disease features. The experiment results demonstrate that the ML ensemble model achieves the best disease prediction accuracy of 88.70%.
Topics: Algorithms; Artificial Intelligence; Cardiovascular Diseases; Heart Diseases; Humans; Machine Learning
PubMed: 36017452
DOI: 10.1155/2022/5267498 -
Cardiovascular Research Jun 2021Modern cardiac electrophysiology has reported significant advances in the understanding of mechanisms underlying complex wave propagation patterns during atrial... (Review)
Review
Modern cardiac electrophysiology has reported significant advances in the understanding of mechanisms underlying complex wave propagation patterns during atrial fibrillation (AF), although disagreements remain. One school of thought adheres to the long-held postulate that AF is the result of randomly propagating wavelets that wonder throughout the atria. Another school supports the notion that AF is deterministic in that it depends on a small number of high-frequency rotors generating three-dimensional scroll waves that propagate throughout the atria. The spiralling waves are thought to interact with anatomic and functional obstacles, leading to fragmentation and new wavelet formation associated with the irregular activation patterns documented on AF tracings. The deterministic hypothesis is consistent with demonstrable hierarchical gradients of activation frequency and AF termination on ablation at specific (non-random) atrial regions. During the last decade, data from realistic animal models and pilot clinical series have triggered a new era of novel methodologies to identify and ablate AF drivers outside the pulmonary veins. New generation electroanatomical mapping systems and multielectrode mapping catheters, complimented by powerful mathematical analyses, have generated the necessary platforms and tools for moving these approaches into clinical procedures. Recent clinical data using such platforms have provided encouraging evidence supporting the feasibility of targeting and effectively ablating driver regions in addition to pulmonary vein isolation in persistent AF. Here, we review state-of-the-art technologies and provide a comprehensive historical perspective, characterization, classification, and expected outcomes of current mechanism-based methods for AF ablation. We discuss also the challenges and expected future directions that scientists and clinicians will face in their efforts to understand AF dynamics and successfully implement any novel method into regular clinical practice.
Topics: Action Potentials; Animals; Atrial Fibrillation; Catheter Ablation; Heart Atria; Heart Rate; Humans; Recurrence; Treatment Outcome
PubMed: 33744913
DOI: 10.1093/cvr/cvab108 -
Frontiers in Neural Circuits 2020Previous studies have shown that cortico-striatal pathways link auditory signals to action-selection and reward-learning behavior through excitatory projections. Only...
Previous studies have shown that cortico-striatal pathways link auditory signals to action-selection and reward-learning behavior through excitatory projections. Only recently it has been demonstrated that long-range GABAergic cortico-striatal somatostatin-expressing neurons in the auditory cortex project to the dorsal striatum, and functionally inhibit the main projecting neuronal population, the spiny projecting neuron. Here we tested the hypothesis that parvalbumin-expressing neurons of the auditory cortex can also send long-range projections to the auditory striatum. To address this fundamental question, we took advantage of viral and non-viral anatomical tracing approaches to identify cortico-striatal parvalbumin neurons (). Here, we describe their anatomical distribution in the auditory cortex and determine the anatomical and electrophysiological properties of layer 5 CS-Parv neurons. We also analyzed their characteristic voltage-dependent membrane potential gamma oscillation, showing that intrinsic membrane mechanisms generate them. The inherent membrane mechanisms can also trigger intermittent and irregular bursts (stuttering) of the action potential in response to steps of depolarizing current pulses.
Topics: Animals; Auditory Cortex; Cerebral Cortex; Corpus Striatum; GABAergic Neurons; Mice; Neural Inhibition; Neurons; Parvalbumins
PubMed: 32792912
DOI: 10.3389/fncir.2020.00045 -
Health Technology Assessment... Jan 2020Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and is associated with an increased risk of stroke and congestive heart failure. Lead-I...
BACKGROUND
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and is associated with an increased risk of stroke and congestive heart failure. Lead-I electrocardiogram (ECG) devices are handheld instruments that can be used to detect AF at a single time point in people who present with relevant signs or symptoms.
OBJECTIVE
To assess the diagnostic test accuracy, clinical impact and cost-effectiveness of using single time point lead-I ECG devices for the detection of AF in people presenting to primary care with relevant signs or symptoms, and who have an irregular pulse compared with using manual pulse palpation (MPP) followed by a 12-lead ECG in primary or secondary care.
DATA SOURCES
MEDLINE, MEDLINE Epub Ahead of Print and MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, PubMed, Cochrane Databases of Systematic Reviews, Cochrane Central Database of Controlled Trials, Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database.
METHODS
The systematic review methods followed published guidance. Two reviewers screened the search results (database inception to April 2018), extracted data and assessed the quality of the included studies. Summary estimates of diagnostic accuracy were calculated using bivariate models. An economic model consisting of a decision tree and two cohort Markov models was developed to evaluate the cost-effectiveness of lead-I ECG devices.
RESULTS
No studies were identified that evaluated the use of lead-I ECG devices for patients with signs or symptoms of AF. Therefore, the diagnostic accuracy and clinical impact results presented are derived from an asymptomatic population (used as a proxy for people with signs or symptoms of AF). The summary sensitivity of lead-I ECG devices was 93.9% [95% confidence interval (CI) 86.2% to 97.4%] and summary specificity was 96.5% (95% CI 90.4% to 98.8%). One study reported limited clinical outcome data. Acceptability of lead-I ECG devices was reported in four studies, with generally positive views. The de novo economic model yielded incremental cost-effectiveness ratios (ICERs) per quality-adjusted life-year (QALY) gained. The results of the pairwise analysis show that all lead-I ECG devices generated ICERs per QALY gained below the £20,000-30,000 threshold. Kardia Mobile (AliveCor Ltd, Mountain View, CA, USA) is the most cost-effective option in a full incremental analysis.
LIMITATIONS
No published data evaluating the diagnostic accuracy, clinical impact or cost-effectiveness of lead-I ECG devices for the population of interest are available.
CONCLUSIONS
Single time point lead-I ECG devices for the detection of AF in people with signs or symptoms of AF and an irregular pulse appear to be a cost-effective use of NHS resources compared with MPP followed by a 12-lead ECG in primary or secondary care, given the assumptions used in the base-case model.
FUTURE WORK
Studies assessing how the use of lead-I ECG devices in this population affects the number of people diagnosed with AF when compared with current practice would be useful.
STUDY REGISTRATION
This study is registered as PROSPERO CRD42018090375.
FUNDING
The National Institute for Health Research Health Technology Assessment programme.
Topics: Atrial Fibrillation; Cost-Benefit Analysis; Electrocardiography; Heart Failure; Humans; Mass Screening; Models, Economic; Predictive Value of Tests; Primary Health Care; Pulse; Quality-Adjusted Life Years; Stroke; Technology Assessment, Biomedical
PubMed: 31933471
DOI: 10.3310/hta24030 -
Frontiers in Bioscience (Scholar... Nov 2022Atrial fibrillation (AF) is a condition in which the electrical signals in the upper heart chambers (atria) are rapid and disorganized, producing an irregular and... (Review)
Review
Atrial fibrillation (AF) is a condition in which the electrical signals in the upper heart chambers (atria) are rapid and disorganized, producing an irregular and chaotical heartbeat. The sinus rhythm should be between 60 to 100 bpm at rest, while the heart rhythm in AF patients may be over 140 bpm. Either structural and electro-mechanical remodeling of the atrial tissue underlies the perpetuation and evolution of AF from the paroxysmal to persistent form. Unravelling the different pathological pathways involved in AF that lead to arrhythmogenesis and atrial remodeling is needed to discovery new and effective therapeutic approaches. A variety of drugs are available to convert and maintain the AF patient in a normal sinus rhythm; however, these strategies have limited chances of success or fail with the progression of AF to more persistent/permanent forms. Consequently, it is necessary to find new therapeutic targets for the relief of persistent or chronic AF forms, as well as the development of new and more effective pharmacological tools. The atrial specific two-pore domain K+ channels (K2P) constitute the background K+ current on atrial cardiomyocytes and modulate cell excitability emerging as novel targets in this disease and avoiding ventricle side effects. Moreover, several antiarrhythmic drugs used in AF treatment exert their mechanism of action in part by modulation of K2P channels. Thus far, TWIK-1, TREK-1, TASK-1, TASK-2 and TASK-3 channel have been identified as responsible for background currents IK2P current in atrial cells; however, it is not excluded that other K2PX subunits or subfamilies have physiological roles in atria. To date, a great diversity openers, activators and blockers of K2P channel have been identified, particularly those targeting TASK and TREK channels. Several studies have demonstrated that the expression of TWIK-1, TREK-1, TASK-1, TASK-2 and TASK-3 are dysregulated in AF and their pharmacology rescue could suppose a novel therapy in AF. The main objective is to examine the regulation of K2P channels and the current K2P channels pharmacological modulators for AF treatment.
Topics: Humans; Atrial Fibrillation; Heart Atria; Anti-Arrhythmia Agents; Heart Rate; Myocytes, Cardiac
PubMed: 36575841
DOI: 10.31083/j.fbs1404031 -
Journal of the Association For Research... Jun 2021Although pitch is closely related to temporal periodicity, stimuli with a degree of temporal irregularity can evoke a pitch sensation in human listeners. However, the...
Although pitch is closely related to temporal periodicity, stimuli with a degree of temporal irregularity can evoke a pitch sensation in human listeners. However, the neural mechanisms underlying pitch perception for irregular sounds are poorly understood. Here, we recorded responses of single units in the inferior colliculus (IC) of normal hearing (NH) rabbits to acoustic pulse trains with different amounts of random jitter in the inter-pulse intervals and compared with responses to electric pulse trains delivered through a cochlear implant (CI) in a different group of rabbits. In both NH and CI animals, many IC neurons demonstrated tuning of firing rate to the average pulse rate (APR) that was robust against temporal jitter, although jitter tended to increase the firing rates for APRs ≥ 1280 Hz. Strength and limiting frequency of spike synchronization to stimulus pulses were also comparable between periodic and irregular pulse trains, although there was a slight increase in synchronization at high APRs with CI stimulation. There were clear differences between CI and NH animals in both the range of APRs over which firing rate tuning was observed and the prevalence of synchronized responses. These results suggest that the pitches of regular and irregular pulse trains are coded differently by IC neurons depending on the APR, the degree of irregularity, and the mode of stimulation. In particular, the temporal pitch produced by periodic pulse trains lacking spectral cues may be based on a rate code rather than a temporal code at higher APRs.
Topics: Animals; Cochlear Implantation; Cochlear Implants; Hearing; Mesencephalon; Pitch Perception; Rabbits
PubMed: 33891217
DOI: 10.1007/s10162-021-00792-5