Autonomic Input Research Articles

Evaluating the physiological benefits of behavioral flexibility in chacma baboons (Papio ursinus) using a biophysical model.

As opportunistic generalists occupying a range of ecological niches, chacma baboons (Papio ursinus) are considered a highly flexible species of relatively low conservation priority. Underlying their ecological flexibility is a repertoire of behavioral strategies observed in response to ecological stressors. Although these strategies are relatively well-documented, we know very little about how they impact upon an individual's thermal and energetic physiology, which can influence population-level reproductive potential in the face of climatic warming. Here, we used Niche Mapper™ to construct a biophysical model that integrates morphometric, autonomic, and behavioral inputs to predict the core body temperature of chacma baboons in response to varied microclimate conditions. The predictive integrity of the model was confirmed by comparing model outputs with the core body temperature of a free-living chacma baboon equipped with an intra-abdominal temperature-sensitive data logger. When behavioral thermoregulation was incorporated, our model predicted body temperature within 1.5°C of the observed temperature for 94% of hours. Of the tested behavioral thermoregulatory responses, shade-seeking provided the greatest thermal benefit, reducing predicted core body temperature by an average of 0.9°C during daytime hours. Evaporative heat-dissipation strategies (sweating or swimming) were also highly effective in circumventing hyperthermia in our modeled individual, with an average body temperature reduction of 0.6°C. Our findings underscore the critical importance of behavioral thermoregulatory strategies coupled with access to essential microhabitat features, water and shade, to achieve homeothermy in a warming climate.

8600 Acute Peripheral Pro-inflammatory Cytokine Injection Results in a Rapid Increase in Microglia Density in the Nucleus of the Solitary Tract

Abstract Disclosure: E.A. Castellanos: None. S.A. Tobet: None. The autonomic nervous system (ANS) is a major integrator of stress responses throughout the body. Physical or psychological stressors lead to neuroendocrine outputs from the hypothalamus and neurotransmitter mediated alterations in circuitry that control peripheral body systems including cardiovascular, pulmonary, and gastrointestinal, among others. Chronic stress can activate immune components, including microglia, leading to increased levels of proinflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-a) in the blood. Increased levels of these cytokines have been associated with several psychiatric disorders including major depressive disorder. In the current study, the impact of pro-inflammatory cytokines was examined in the dorsal vagal complex (DVC), a key brainstem region responsible for integrating autonomic inputs and outputs. The DVC includes the area postrema (AP), a sensory circumventricular organ, the nucleus of the solitary tract (NTS), and the vagal dorsal motor complex. The AP is in the middle of the DVC region, adjacent to cerebrospinal fluid and lacking a blood brain barrier (i.e., fenestrated capillaries). These traits make the AP uniquely located to integrate peripheral and central interactions between circulating cytokines and select immune cells in the DVC. This study concentrated on the effects of a single peripheral injection on microglia quantities in the DVC. TNF-a (50µg/Kg) and IL-6 (50µg/Kg) were administered by intraperitoneal injection and 2h later animals were perfused with 4% paraformaldehyde. Immunoreactive ionized calcium-binding adapter molecule 1 (IBA1) was used to identify microglia in the brainstem. In the area postrema there was a trend towards more immunoreactive IBA1 total area (µm^2; p = 0.08, ns) in mice that were injected with TNF-a and IL-6 compared to controls. By contrast, in the adjacent NTS there was 1.5x’s more immunoreactive IBA1 in mice that were injected with IL-6 and TNF-a (µm^2; p < 0.001) compared to control vehicle injections. Comparing brain regions in the DVC, there is 1.7x more microglia cells in the area postrema per section (50µm) compared to the NTS (p < 0.001), but in the NTS cells are 1.3x larger in size in comparison to the microglia cells in the AP overall (µm^2/ number of cells; p < 0.05). Finally, in the NTS there was a 1.5x larger total area of the IBA1 immunoreactivity following TNF-a injections compared to IL-6 injected mice (µm^2; p < 0.05). These data reveal a rapid effect of peripherally injected pro-inflammatory cytokines on microglial quantities and size in the brainstem. Future investigations will elucidate the role of neural-immune pathways in influencing the ANS during a chronic immune stress response. Supported by ORWH U54-MH118919. Presentation: 6/3/2024

Abstract Mo131: Time-Restricted Feeding Normalizes Dim Light at Night-Induced Disruption of Cardiovascular Rhythms in Mice

Background: Light input to the suprachiasmatic nucleus entrains circadian rhythms in physiology and behavior to the day-night cycle. Exposure to light at night in people is associated with cardiometabolic disease. Pre-clinical studies show that artificial light at night, including at very low levels, disrupts day-night rhythms in activity, feeding behavior, heart rate, and blood pressure dipping. Hypothesis: Dim light at night (dLAN) disrupts day-night rhythms in feeding behavior to blunt day-night rhythms in autonomic input to the heart and blood pressure dipping. Methods: Mice (n=5-6/sex) in thermoneutral housing were implanted with telemetry probes to record heart rate, blood pressure, and core body temperature. Autonomic input to the heart was assessed by measuring heart rate and subtracting the temperature-dependent changes in the heart rate after pharmacological inhibition of muscarinic and β-adrenergic receptor activation. Mice were housed in 12 h light: 12 h dark cycles (LD, 200 lux: 0 lux) with ad libitum access to food (LD-ALF), subjected to 12 h light: 12 h dLAN cycles (dLAN-ALF; 200 lux: 5 lux) for two weeks, and then feeding was time-restricted (not calorically restricted) to the dLAN cycle (dLAN-RF). Data were extracted from Ponemah and Clocklab, and statistical analysis was done using GraphPad PRISM software. Results: Compared to LD-ALF mice, dLAN-ALF mice showed reduced amplitudes in day-night activity, feeding, heart rate, and blood pressure rhythms, with males more affected than females (p<0.001). dLAN-ALF male and female mice had decreased amplitudes in the day-night rhythms in autonomic input to the heart. In addition, dLAN-ALF male mice had less blood pressure dipping. dLAN-RF normalized autonomic input to the heart and heart rate in male and female mice (p<0.05, p<0.01, respectively). dLAN-RF also improved blood pressure dipping in male mice (p<0.001). dLAN-RF did not normalize activity rhythms. Conclusion: dLAN disrupts day-night rhythms in activity, feeding, heart rate, and blood pressure dipping in mice, with males being more impacted. Time-restricted feeding to the dLAN cycle normalizes autonomic input to the heart and blood pressure dipping. These data suggest that time-restricted feeding counteracts the light-at-night-induced circadian disruption of cardiovascular function.

Abstract We114: Feeding Behavior Underlies the Circadian Rhythm in the Autonomic Input to the Heart and Heart Rate

Objective: The circadian pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus drives circadian rhythms in feeding and activity. Several studies suggest the SCN regulates autonomic input to the heart to generate day-night rhythms in heart rate. Hypothesis: The circadian rhythm in feeding generates day-night rhythms in autonomic input to the heart and heart rate. Methodology: Mice (n=6/sex) were implanted with telemetry probes to continuously record heart rate, core body temperature, and activity in thermoneutral housing conditions. Mice were housed in a 12 h light: 12 h dark cycle (LD) with ad libitum access to food (ALF). In these conditions, mice primarily eat during the dark cycle. Mice were subjected to light phase time-restricted feeding (TRF) for 5 days. This forces the mice to eat during the light cycle. We quantified changes in autonomic input to the heart by injecting mice with the autonomic receptor inhibitors propranolol and methylatropine. To determine if circadian rhythms generate day-night rhythms in autonomic input to the heart, TRF mice were switched from LD to constant darkness (DD) and then returned to ALF in DD. Results: ALF mice housed in LD had 24-hour rhythms in autonomic input to the heart, heart rate, and activity that all peaked in alignment during the dark cycle. One day after starting TRF, the phase of the 24-hour rhythms in heart rate but not activity shifted by 8-10 hours to align with feeding during the light phase. Switching TRF mice in LD to DD did not alter the phase or amplitude of the day-night rhythms in autonomic input to the heart, heart rate, or activity. Returning the TRF mice in DD to ALF showed the autonomic input to the heart and heart rate re-aligned with the free running rhythm in activity. Conclusions: Day-night rhythms in heart rate and autonomic input to the heart align with activity in LD and DD in ad libitum fed but not time-restricted fed conditions. These data demonstrate that feeding behavior, not SCN-signaling or activity rhythms, drives day-night rhythms in autonomic input to the heart and heart rate.

Feeding behavior modifies the circadian variation in RR and QT intervals by distinct mechanisms in mice.

Rhythmic feeding behavior is critical for regulating phase and amplitude in the ≈24-h variation of heart rate (RR intervals), ventricular repolarization (QT intervals), and core body temperature in mice. We hypothesized changes in cardiac electrophysiology associated with feeding behavior were secondary to changes in core body temperature. Telemetry was used to record electrocardiograms and core body temperature in mice during ad libitum-fed conditions and after inverting normal feeding behavior by restricting food access to the light cycle. Light cycle-restricted feeding modified the phase and amplitude of 24-h rhythms in RR and QT intervals, and core body temperature to realign with the new feeding time. Changes in core body temperature alone could not account for changes in phase and amplitude in the ≈24-h variation of the RR intervals. Heart rate variability analysis and inhibiting β-adrenergic and muscarinic receptors suggested that changes in the phase and amplitude of 24-h rhythms in RR intervals were secondary to changes in autonomic signaling. In contrast, changes in QT intervals closely mirrored changes in core body temperature. Studies at thermoneutrality confirmed that the daily variation in QT interval, but not RR interval, primarily reflected daily changes in core body temperature (even in ad libitum-fed conditions). Correcting the QT interval for differences in core body temperature helped unmask QT interval prolongation after starting light cycle-restricted feeding and in a mouse model of long QT syndrome. We conclude feeding behavior alters autonomic signaling and core body temperature to regulate phase and amplitude in RR and QT intervals, respectively.NEW & NOTEWORTHY We used time-restricted feeding and thermoneutrality to demonstrate that different mechanisms regulate the 24-h rhythms in heart rate and ventricular repolarization. The daily rhythm in heart rate reflects changes in autonomic input, whereas daily rhythms in ventricular repolarization reflect changes in core body temperature. This novel finding has major implications for understanding 24-h rhythms in mouse cardiac electrophysiology, arrhythmia susceptibility in transgenic mouse models, and interpretability of cardiac electrophysiological data acquired in thermoneutrality.

Electrophysiology and 3D-imaging reveal properties of human intracardiac neurons and increased excitability with atrial fibrillation.

Altered autonomic input to the heart plays a major role in atrial fibrillation (AF). Autonomic neurons termed ganglionated plexi (GP) are clustered on the heart surface to provide the last point of neural control of cardiac function. To date the properties of GP neurons in humans are unknown. Here we have addressed this knowledge gap in human GP neuron structure and physiology in patients with and without AF. Human right atrial GP neurons embedded in epicardial adipose tissue were excised during open heart surgery performed on both non-AF and AF patients and then characterised physiologically by whole cell patch clamp techniques. Structural analysis was also performed after fixation at both the single cell and at the entire GP levels via three-dimensional confocal imaging. Human GP neurons were found to exhibit unique properties and structural complexity with branched neurite outgrowth. Significant differences in excitability were revealed between AF and non-AF GP neurons as measured by lower current to induce action potential firing, a reduced occurrence of low action potential firing rates, decreased accommodation and increased synaptic density. Visualisation of entire GPs showed almost all neurons are cholinergic with a small proportion of noradrenergic and dual phenotype neurons. Phenotypic distribution differences occurred with AF including decreased cholinergic and dual phenotype neurons, and increased noradrenergic neurons. These data show both functional and structural differences occur between GP neurons from patients with and without AF, highlighting that cellular plasticity occurs in neural input to the heart that could alter autonomic influence on atrial function. KEY POINTS: The autonomic nervous system plays a critical role in regulating heart rhythm and the initiation of AF; however, the structural and functional properties of human autonomic neurons in the autonomic ganglionated plexi (GP) remain unknown. Here we perform the first whole cell patch clamp electrophysiological and large tissue confocal imaging analysis of these neurons from patients with and without AF. Our data show human GP neurons are functionally and structurally complex. Measurements of action potential kinetics show higher excitability in GP neurons from AF patients as measured by lower current to induce action potential firing, reduced low firing action potential rates, and decreased action potential accommodation. Confocal imaging shows increased synaptic density and noradrenergic phenotypes in patients with AF. Both functional and structural differences occur in GP neurons from patients with AF that could alter autonomic influence on atrial rhythm.

Central Autonomic Network and Heart Rate Variability in Premature Neonates

Introduction: The Central Autonomic Network (CAN) is a hierarchy of brain structures that collectively influence cardiac autonomic input, mediating the majority of brain-heart interactions, but has never been studied in premature neonates. In this study, we use heart rate variability (HRV), which has been described as the “primary output” of the CAN, and resting-state functional MRI (rsfMRI) to characterize brain-heart relationships in premature neonates. Methods: We studied premature neonates who underwent rsfMRI at term (37-week postmenstrual age or above) and had HRV data recorded during the same week of their MRI. HRV was derived from continuous electrocardiogram data during the week of the rsfMRI scan. For rsfMRI, a seed-based approach was used to define regions of interest (ROIs) pertinent to the CAN, and blood oxygen level-dependent signal was correlated between each ROI as a measure of functional connectivity. HRV was correlated with CAN connectivity (CANconn) for each region, and subgroup analysis was performed based on sex and clinical comorbidities. Results: Forty-seven premature neonates were included in this study, with a mean gestational age at birth of 28.1 +/− 2.6 weeks. Term CANconn was found to be significantly correlated with HRV in approximately one-fifth of CAN connections. Two distinct patterns emerged among these HRV-CANconn relationships. In the first, increased HRV was associated with stronger CANconn of limbic regions. In the second pattern, stronger CANconn at the precuneus was associated with impaired HRV maturation. These patterns were especially pronounced in male premature neonates. Conclusion: We report for the first time evidence of brain-heart relationships in premature neonates and an emerging CAN, most striking in male neonates, suggesting that the brain-heart axis may be more vulnerable in male premature neonates. Signatures in the heart rate may eventually become an important noninvasive tool to identify premature males at highest risk for neurodevelopmental impairment.

Pulmonary vein isolation versus PVI + adjunctive strategy (substrate modification and renal denervation therapy) for the reduction of 12-month AF recurrence

Abstract Background of the Study This meta-analysis assessed the latest evidence on the use of adjunct ablation strategies to standard pulmonary vein isolation (PVI) for treating atrial fibrillation (AF). Adjunct treatments were further classified as substrate modification (posterior wall isolation, linear ablation and ablation of complex fractionated atrial electrograms) or renal denervation (RDN). Purpose While ablation maintains sinus rhythm more effectively than antiarrhythmic drug therapy, recurrent AF remains common after 12 months, occurring in up to 40-60% of patients undergoing standard PVI ablation. Treatment strategies have diversified in a response to these challenges. These include reduction of the arrhythmogenic substrate, modulation of autonomic inputs and improvement of risk factors, such as hypertension. Methods A systematic literature search from MEDLINE and PubMed electronic databases was performed until November 2022. The primary outcome was 12-month AF recurrence defined as AF lasting ≥30 seconds on follow-up. The secondary outcome was incidence of procedure-related major adverse events (MAEs), defined as death, clinical strokes, acute heart failure decompensation, pericardial effusion causing tamponade, arteriovenous fistulas, and atrioesophageal fistulas. Results Nine studies comprising 1686 patients were included in the final analysis. AF recurrence was 487/1082 (45%) in the PVI + Adjunct group and 204/604 (33.8%) in PVI Alone. Pooled analysis showed that PVI + adjunct was inconclusively associated with less incidence of 12-month AF recurrence (RR 0.79, 95% CI 0.60–1.04, I2 = 70%, p-value 0.09). Subgroup analyses of six RCTs under the PVI with substrate modification arm showed non-significant increase in 12-month AF recurrence in PVI + substrate modification (RR 0.85, 95% CI 0.6-1.21, p-value 0.38). Subgroup analyses of the 3 RCTs on hypertensive AF patients showed strong evidence of decreased 12-month AF recurrence in PVI + RDN compared to PVI alone (RR 0.65, 95% CI 0.48-0.89, p-value 0.007). Secondary outcome of major adverse procedure-related events in overall pooled analysis showed 8 events in 604 patients undergoing PVI alone, and 23 events in 1082 patients undergoing PVI + adjunct ablation. There is no significant difference in the number of reported MAE in PVI alone over PVI + adjunct (RR 1.16 [0.49-2.75], p = 0.73). Conclusion Overall, PVI with adjunctive strategies did not significantly reduce 12-month AF recurrence after ablation. Among these strategies, RDN demonstrated a significant reduction in the primary endpoint, whereas substrate modification did not. There was no significant difference in MAEs reported between standard therapy versus those with adjunctive treatment. We conclude that PVI ablation strategies should be individualized, and modification of both triggers and risk factors for AF show better rhythm control on follow-up.

A Descriptive Research of Decreased Heart Rate Variability as a Risk Factor for Cardiovascular Disease in Young, Healthy Adults with Low and High BMI Indexes

Background and objectives: HRV is used to evaluate autonomic nervous system input to the heart. Several studies have examined the effect of HRV on underweight status. To assess HRV in age-matched young people with varying BMI categories. Methods: This cross-sectional study was conducted on healthy young adults between the ages of 18 and 25. Variables of anthropometrics were measured. ECG was recorded for 5 minutes in lead II setup. Kubios HRV analyzer was used to evaluate heart rate variability. Results: HRV indices were lower in the underweight, overweight, and obese BMI groups compared to the normal weight group. Both genders exhibit an inverted U-shaped association between BMI and HF log power based on second-order polynomial regression. The correlation between BMI, waist circumference, and body fat (%) and HRV indices demonstrates a substantial relationship with heart rate variability, with waist circumference (WC) exhibiting a stronger relationship than BMI. Comparing HRV parameters between men and women of different BMI groups reveals that women exhibited more heart rate variability than men across BMI groups. Conclusion: Underweight individuals share the same elevated cardiovascular risk as the obese, and abdominal obesity is a more accurate predictor of cardiovascular risk than the body mass index (BMI).

Promoting Honesty in Children, or Fostering Pathological Behaviour?

Promoting Honesty in Children, or Fostering Pathological Behaviour?

Parasympathetic and sympathetic control of emmetropization in chick

Emmetropization can be altered by temporal visual stimulation and the spectral properties of the visual environment. The goal of the current experiment is to test the hypothesis that there is an interaction between these properties and autonomic innervation. For that purpose, selective lesions of the autonomic nervous system were performed in chickens followed by temporal stimulation. Parasympathetic lesioning involved transection of both the ciliary ganglion and the pterygopalatine ganglion (PPG_CGX; n = 38), while sympathetic lesioning involved transection of the superior cervical ganglion (SCGX; n = 49). After one week of recovery, chicks were then exposed to temporally modulated light (3 days, 2 Hz, Mean: 680 lux) that was either achromatic (with blue [RGB], or without blue [RG]), or chromatic (with blue [B/Y] or without blue [R/G]). Control birds with lesions, or unlesioned, were exposed to white [RGB] or yellow [RG] light. Ocular biometry and refraction (Lenstar and a Hartinger refractometer) was measured before and after exposure to light stimulation. Measurements were statistically analyzed for the effects of a lack of autonomic input and the type of temporal stimulation.In PPG_CGX lesioned eyes, there was no effect of the lesions one-week post-surgery. However, after exposure to achromatic modulation, the lens thickened (with blue) and the choroid thickened (without blue) but there was no effect on axial growth. Chromatic modulation thinned the choroid with R/G.In the SGX lesioned eye, there was no effect of the lesion 1-week post-surgery. However, after exposure to achromatic modulation (without blue), the lens thickened and there was a reduction in vitreous chamber depth and axial length. Chromatic modulation caused a small increase in vitreous chamber depth with R/G.Both autonomic lesion and visual stimulation were necessary to affect the growth of ocular components. The bidirectional responses observed in axial growth and in choroidal changes suggest that autonomic innervation combined with spectral cues from longitudinal chromatic aberration may provide a mechanism for homeostatic control of emmetropization.

Autonomous Input Voltage Sharing Control and Triple Phase Shift Modulation Method for ISOP-DAB Converter in DC Microgrid: A Multiagent Deep Reinforcement Learning-Based Method

This article proposes a multiagent (MA) deep reinforcement learning (DRL) based autonomous input voltage sharing (IVS) control and triple phase shift modulation method for input-series output-parallel (ISOP) dual active bridge (DAB) converters to solve the three challenges: the uncertainties of the dc microgrid, the power balance problem, and the current stress minimization of the converter. Specifically, the control and modulation problem of the ISOP-DAB converter is formed as a Markov game with several DRL agents. Subsequently, the MA twin-delayed deep deterministic policy gradient (MA-TD3) algorithm is applied to train the DRL agents in an offline manner. After the training process, the multiple agents can provide online control decisions for the ISOP-DAB converter to balance the IVS, and minimize the current stress among different submodules. Without accurate model information, the proposed method can adaptively obtain the optimal modulation variable combinations in a stochastic and uncertain environment. Simulation and experimental results verify the effectiveness of the proposed MA-TD3-based algorithm.

Dynamic fluctuations in ascending heart-to-brain communication under mental stress.

Dynamical information exchange between central and autonomic nervous systems, as referred to functional brain-heart interplay, occurs during emotional and physical arousal. It is well documented that physical and mental stress lead to sympathetic activation. Nevertheless, the role of autonomic inputs in nervous system-wise communication under mental stress is yet unknown. In this study, we estimated the causal and bidirectional neural modulations between electroencephalogram (EEG) oscillations and peripheral sympathetic and parasympathetic activities using a recently proposed computational framework for a functional brain-heart interplay assessment, namely the sympathovagal synthetic data generation model. Mental stress was elicited in 37 healthy volunteers by increasing their cognitive demands throughout three tasks associated with increased stress levels. Stress elicitation induced an increased variability in sympathovagal markers, as well as increased variability in the directional brain-heart interplay. The observed heart-to-brain interplay was primarily from sympathetic activity targeting a wide range of EEG oscillations, whereas variability in the efferent direction seemed mainly related to EEG oscillations in the γ band. These findings extend current knowledge on stress physiology, which mainly referred to top-down neural dynamics. Our results suggest that mental stress may not cause an increase in sympathetic activity exclusively as it initiates a dynamic fluctuation within brain-body networks including bidirectional interactions at a brain-heart level. We conclude that directional brain-heart interplay measurements may provide suitable biomarkers for a quantitative stress assessment and bodily feedback may modulate the perceived stress caused by increased cognitive demand.

Vestibular Contributions to Primate Neck Postural Muscle Activity during Natural Motion.

To maintain stable posture of the head and body during our everyday activities, the brain integrates information across multiple sensory systems. Here, we examined how the primate vestibular system, independently and in combination with visual sensory input, contributes to the sensorimotor control of head posture across the range of dynamic motion experienced during daily life. We recorded activity of single motor units in the splenius capitis and sternocleidomastoid muscles in rhesus monkeys during yaw rotations spanning the physiological range of self-motion (up to 20 Hz) in darkness. Splenius capitis motor unit responses continued to increase with frequency up to 16 Hz in normal animals, and were strikingly absent following bilateral peripheral vestibular loss. To determine whether visual information modulated these vestibular-driven neck muscle responses, we experimentally controlled the correspondence between visual and vestibular cues of self-motion. Surprisingly, visual information did not influence motor unit responses in normal animals, nor did it substitute for absent vestibular feedback following bilateral peripheral vestibular loss. A comparison of muscle activity evoked by broadband versus sinusoidal head motion further revealed that low-frequency responses were attenuated when low- and high-frequency self-motion were experienced concurrently. Finally, we found that vestibular-evoked responses were enhanced by increased autonomic arousal, quantified via pupil size. Together, our findings directly establish the vestibular system's contribution to the sensorimotor control of head posture across the dynamic motion range experienced during everyday activities, as well as how vestibular, visual, and autonomic inputs are integrated for postural control.SIGNIFICANCE STATEMENT Our sensory systems enable us to maintain control of our posture and balance as we move through the world. Notably, the vestibular system senses motion of the head and sends motor commands, via vestibulospinal pathways, to axial and limb muscles to stabilize posture. By recording the activity of single motor units, here we show, for the first time, that the vestibular system contributes to the sensorimotor control of head posture across the dynamic motion range experienced during everyday activities. Our results further establish how vestibular, autonomic, and visual inputs are integrated for postural control. This information is essential for understanding both the mechanisms underlying the control of posture and balance, and the impact of the loss of sensory function.

Student conceptual level scale: Development and initial validation

The conceptual level is an index of personality development. In the field of teaching, the conceptual level is seen as a dynamic learning style. It has important implications for student learning and individual growth, as well as guidance for teaching. However, the lack of a measurement tool with a clear internal structure for the conceptual level of students has slowed the development of the theory and made it difficult to implement the teaching. To address these issues, this study describes the initial development and validation of the Student Conceptual Level Scale (SCLS) with four samples of students (n = 1,321) drawn from eight secondary schools in China. We constructed a second-order three-factor model of the SCLS consisting of three factors—learning awareness level, autonomous input level, and environmental coping level—each with its own independent set of items. This study validated the use of full-scale and subscale scores and examined their relationship with different validity criteria: autonomous learning, mental effort, and academic scores. This updated measure reflects the value and role of the conceptual level in the learning and individual development of students and also provides a more complete frame of reference for the use of the conceptual level in teaching and learning.

Reduced Heart Rate Variability as A Risk Factor for Cardiovascular Disease in Young Healthy Adults with Low and High Body Mass Indexes – A Descriptive Study

Background: Heart rate variability (HRV) is a used to assess autonomic nervous system input to the heart. Studies on the impact of HRV on underweight are limited. Aims/Objectives: To evaluate HRV in age matched young adults of different BMI category. Methodology: This cross-sectional study was done among healthy young adult volunteers between 18 and 25 years of age. Anthropometric variables were measured. ECG was recorded in lead II configuration for 5 minutes. Heart rate variability was analysed with Kubios HRV analyzer. Results: HRV indices were reduced in underweight (UW), overweight (OW) and obese group compared to normal weight (NW) BMI group. Second order polynomial regression between BMI and HF log power in both genders shows an inverted U-shaped relationship with BMI. The association between BMI, waist circumference and body fat (percentage) with HRV indices shows a significant relation to heart rate variability among which waist circumference (WC) shows a greater association with HRV indices than BMI. Comparison of HRV parameters among men and women of different BMI group shows female had greater heart rate variability compared to males across BMI Conclusions: underweight individual also have increased cardiovascular risk like obese group and abdominal obesity is better indicator of cardiovascular risk than BMI.

Understanding the roles of central and autonomic activity during sleep in the improvement of working memory and episodic memory

The last decade has seen significant progress in identifying sleep mechanisms that support cognition. Most of these studies focus on the link between electrophysiological events of the central nervous system during sleep and improvements in different cognitive domains, while the dynamic shifts of the autonomic nervous system across sleep have been largely overlooked. Recent studies, however, have identified significant contributions of autonomic inputs during sleep to cognition. Yet, there remain considerable gaps in understanding how central and autonomic systems work together during sleep to facilitate cognitive improvement. In this article we examine the evidence for the independent and interactive roles of central and autonomic activities during sleep and wake in cognitive processing. We specifically focus on the prefrontal–subcortical structures supporting working memory and mechanisms underlying the formation of hippocampal-dependent episodic memory. Our Slow Oscillation Switch Model identifies separate and competing underlying mechanisms supporting the two memory domains at the synaptic, systems, and behavioral levels. We propose that sleep is a competitive arena in which both memory domains vie for limited resources, experimentally demonstrated when boosting one system leads to a functional trade-off in electrophysiological and behavioral outcomes. As these findings inevitably lead to further questions, we suggest areas of future research to better understand how the brain and body interact to support a wide range of cognitive domains during a single sleep episode.

Emergence of heartbeat frailty in advanced age I: perspectives from life-long EKG recordings in adult mice

The combined influences of sinoatrial nodal (SAN) pacemaker cell automaticity and its response to autonomic input determine the heart’s beating interval variability and mean beating rate. To determine the intrinsic SAN and autonomic signatures buried within EKG RR interval time series change in advanced age, we measured RR interval variability before and during double autonomic blockade at 3-month intervals from 6 months of age until the end of life in long-lived (those that achieved the total cohort median life span of 24 months and beyond) C57/BL6 mice. Prior to 21 months of age, time-dependent changes in intrinsic RR interval variability and mean RR interval were relatively minor. Between 21 and 30 months of age, however, marked changes emerged in intrinsic SAN RR interval variability signatures, pointing to a reduction in the kinetics of pacemaker clock mechanisms, leading to reduced synchronization of molecular functions within and among SAN cells. This loss of high-frequency signal processing within intrinsic SAN signatures resulted in a marked increase in the mean intrinsic RR interval. The impact of autonomic signatures on RR interval variability were net sympathetic and partially compensated for the reduced kinetics of the intrinsic SAN RR interval variability signatures, and partially, but not completely, shifted the EKG RR time series intervals to a more youthful pattern. Cross-sectional analyses of other subsets of C57/BL6 ages indicated that at or beyond the median life span of our longitudinal cohort, noncardiac, constitutional, whole-body frailty was increased, energetic efficiency was reduced, and the respiratory exchange ratio increased. We interpret the progressive reduction in kinetics in intrinsic SAN RR interval variability signatures in this context of whole-body frailty beyond 21 months of age to be a manifestation of “heartbeat frailty.”

Determining the efficiency of data analysis systems in predicting COVID-19 infected cases.

ABSTRACTAfter the outbreak of the novel coronavirus disease (2019) (COVID-19), a lot of people have been affected around the world. Due to the large number of affected patients in the world, the global health care system has been disrupted and nearly all hospitals around the world has faced a shortage of bed spaces. As a consequence, being able of prediction of the number of COVID-19 cases is extremely important for taking appropriate decision for management of the affected patients. An accurate prediction of the number of COVID-19 cases Can be obtained using the historical data of reported cases as well as some other data affecting the virus outbreak. However, most of the literature has used only historical data to provide a method of predicting COVID-19 cases and has neglected other influential factors. This has led to inaccurate estimates of the number of infected cases with COVID-19. Thus, the present study tries to provide a more accurate estimation of the number of COVID-19 cases by considering both historical data and other effective factors on the virus. For this purpose, data analysis including the development of a network-based neural algorithm [i.e., nonlinear autonomous exogenous input (NARX)] can be adopted. To examine the viability of this algorithm, experiments were conducted using data collected for the number of COVID-19 cases in the five most affected countries on each continent. Our method led to a more accurate prediction than those obtained by the existing methods. Moreover, we performed experiments to extend our method to predict the number of COVID-19 cases in the future during a period between August 2020 and September 2020. Such predictions can be utilized by the government or people in the affected countries to take precautionary measures against the pandemic.

An Osteopathic Manipulative Treatment (OMT) Evaluation and Treatment Protocol to Improve Gastrointestinal Function

Abstract As a hands-on approach to patient care diagnosis and management, osteopathic manipulative medicine (OMM) can be utilized to modulate the autonomic input to the gastrointestinal system. Palpatory findings of tissue texture changes at predictable body regions may correspond to visceral dysfunction related to the gastrointestinal (GI) system.1 Osteopathic manipulative treatment (OMT) of the viscero-somatic segment or viscero-visceral reflex can remove the feedback related to the somatic or visceral component, thereby affecting nociceptive facilitation at the spinal or visceral level and helping to restore autonomic balance.1,2 The purpose of this thesis is to describe an evaluation and treatment protocol to address somatic and visceral dysfunction found in many patients with impaired gastrointestinal function. A retrospective analysis of 5 patients will be outlined using the evaluation and treatment protocol. The safety of an OMT evaluation and treatment protocol as applied to address gastrointestinal function and as outlined in the current literature will also be addressed.