The Redistribution of Power: Neurocardiac Signaling, Alcohol and Gender

Human adaptability involves interconnected biological and psychological control processes that determine how successful we are in meeting internal and environmental challenges. Heart rate variability (HRV), the variability in consecutive R-wave to R-wave intervals (RRI) of the electrocardiogram, captures synergy between the brain and cardiovascular control systems that modulate adaptive responding. Here we introduce a qualitatively new dimension of adaptive change in HRV quantified as a redistribution of spectral power by applying the Wasserstein distance with exponent 1 metric (W1) to RRI spectral data. We further derived a new index, D, to specify the direction of spectral redistribution and clarify physiological interpretation. We examined gender differences in real time RRI spectral power response to alcohol, placebo and visual cue challenges. Adaptive changes were observed as changes in power of the various spectral frequency bands (i.e., standard frequency domain HRV indices) and, during both placebo and alcohol intoxication challenges, as changes in the structure (shape) of the RRI spectrum, with a redistribution towards lower frequency oscillations. The overall conclusions from the present study are that the RRI spectrum is capable of a fluid and highly flexible response, even when oscillations (and thus activity at the sinoatrial node) are pharmacologically suppressed, and that low frequency oscillations serve a crucial but less studied role in physical and mental health

Heart Rate Variability (HRV) biofeedback: a new training approach for operator’s performance enhancement

The widespread implementation of advanced and complex systems requires predominantly operators’ cognitive functions and less importance of human manual control. On the other hand, most operators perform their cognitive functions below their peak cognitive capacity level due to fatigue, stress, and boredom. Thus, there is a need to improve their cognitive functions during work. The goal of this paper is to present a psychophysiology training approach derived from cardiovascular response named heart rate variability (HRV) biofeedback. Description of resonant frequency biofeedback - a specific HRV training protocol - is discussed as well as its supported researches for the performance enhancement. HRV biofeedback training works by teaching people to recognize their involuntary HRV and to control patterns of this physiological response. The training is directed to increase HRV amplitude that promotes autonomic nervous system balance. This balance is associated with improved physiological functioning as well as psychological benefits. Most individuals can learn HRV biofeedback training easily which involves slowing the breathing rate (around six breaths/min) to each individual’s resonant frequency at which the amplitude of HRV is maximized. Maximal control over HRV can be obtained in most people after approximately four sessions of training. Recent studies have demonstrated the effectiveness of HRV biofeedback to the improvement of some cognitive functions in both simulated and real industrial operators.Peer Reviewe

Heart Rate Variability (HRV) biofeedback: A new training approach for operator's performance enhancement

The widespread implementation of advanced and complex systems requires predominantly operators’ cognitive functions and less importance of human manual control. On the other hand, most operators perform their cognitive functions below their peak cognitive capacity level due to fatigue, stress, and boredom. Thus, there is a need to improve their cognitive functions during work. The goal of this paper is to present a psychophysiology training approach derived from cardiovascular response named heart rate variability (HRV) biofeedback. Description of resonant frequency biofeedback - a specific HRV training protocol - is discussed as well as its supported researches for the performance enhancement. HRV biofeedback training works by teaching people to recognize their involuntary HRV and to control patterns of this physiological response. The training is directed to increase HRV amplitude that promotes autonomic nervous system balance. This balance is associated with improved physiological functioning as well as psychological benefits. Most individuals can learn HRV biofeedback training easily which involves slowing the breathing rate (around six breaths/min) to each individual’s resonant frequency at which the amplitude of HRV is maximized. Maximal control over HRV can be obtained in most people after approximately four sessions of training. Recent studies have demonstrated the effectiveness of HRV biofeedback to the improvement of some cognitive functions in both simulated and real industrial operators

The Influence of Sex on the Relationship Between Arterial Mechanical Properties and Cardiovagal Baroreflex Sensitivity

Cardiovagal baroreflex sensitivity (cvBRS) demonstrates a strong relationship with arterial mechanical properties. Both cvBRS and arterial mechanics differ by sex such that males demonstrate greater cvBRS, yet lower large artery elasticity than females. Whether the relationship between cvBRS and arterial mechanics is similar in males and females remains unexamined. As a result, it is unclear whether arterial mechanics contribute to sex differences in cvBRS. This study investigated the cross-sectional relationship between cvBRS and arterial mechanical properties of the common carotid, carotid sinus and aortic arch (AA) in 36 (18 females) young, healthy normotensives. The cvBRS-arterial mechanics relationship did not reach statistical significance and did not differ by sex. Both cvBRS and AA distensibility were greater in females than males. Sex differences in cvBRS were eliminated after controlling for AA distensibility. These findings suggest that in this sample, AA elasticity may contribute to the greater cvBRS in females than males

Abnormal cardiovascular sympathetic and parasympathetic responses to physical and emotional stimuli in depersonalization disorder

BACKGROUND: Depersonalization disorder (DPD) is characterized by a subjective sense of unreality, disembodiment, emotional numbing and reduced psychogenic (sudomotor) sympathoexcitation. AIMS: Three related experiments utilized escalating physical and emotional challenges in 14 DPD participants and 16 controls aimed to elucidate (i) whether the cardiovascular sympathetic (SNS) and parasympathetic (PNS) nervous systems are implicated in DPD pathophysiology and (ii) if possible, to determine whether the blunted sympathoexcitation in DPD is peripherally or centrally mediated. METHOD: Participants completed the Beck Anxiety Inventory (BAI), Dissociative Experience Scale (DES), and Cambridge Depersonalization Scale (CDS). Study I recorded heart rate (HR) and blood pressure (BP) during 5 min supine baseline, 3 min sustained handgrip (HG), 3 min cold pressor (CP) and 5 min 60° head-up tilt (HUT). In study II, HR, BP, and heart rate variability (HRV) were recorded during 5 min simultaneous 60° HUT and continuous presentation of unpleasant images (5 s per image). Study III examined HR and BP orienting responses (ORs) to simultaneous 60° HUT and pseudorandom presentation of unpleasant, neutral and pleasant images (5 s per image 3 min 25 s). OR data was grouped by image valence post hoc. RESULTS: DPD BAI (p = 0.0004), DES (p = 0.0002), and CDS (p ≤ 0.0001) scores were higher than controls. The DPD group produced diminished diastolic BP (DBP) (p = 0.045) increases to HG. Other indices were comparable between groups. DPD participants produced diminished systolic BP (SBP) (p = 0.003) and DBP (p = 0.002) increases, but greater (p = 0.004) HR increases to CP. In study II, DPD high frequency HRV (HF-HRV)-indicating parasympathetic vagal activity-was reduced (p = 0.029). In study III, DPD DBP was higher throughout the 5 s duration of HUT/pseudorandom unpleasant image presentation (1 s, p = 0.002, 2 s p = 0.033, 3 s p = 0.001, 4 s p = 0.009, 5 s p = 0.029). CONCLUSIONS: Study I's BP pressor data supports previous findings of suppressed sympathoexcitation in DPD. The greater HR increases to CP, decreased HF-HRV in study II, and increased DBP during unpleasant ORs in study III implicates the SNS and PNS in DPD pathophysiology. These studies suggest the cardiovascular autonomic dysregulation in DPD is likely to be centrally-mediated

Impacts of systemic hemodynamic factors on cerebral and peripheral perfusion

Changes in physiological factors involving modulation of hemodynamics such as baroreflex sensitivity (BRS), heart rate, and/or blood pressure influence blood flow to downstream tissues leading to changes in response and/or function of tissues. For example, a sufficient increase in heart rate elicits greater accumulative shear stimuli on a per minute basis leading to a greater vasodilatory response of endothelial cells and providing greater perfusion to skeletal muscle. The high-flow and low-impedance nature of the cerebral circulation leads to increased susceptibility to damage from considerable blood pressure fluctuations. For this reason, the cerebrovasculature holds a very narrow range of operation of cerebral autoregulation in response to changes in perfusion pressure. In a nondemented elderly population and patients with Alzheimer’s disease, impaired BRS has been linked with poor cognitive function and a link between high pulsatile components of blood pressure (i.e., pulse pressure) and impaired cognitive function has also been reported. Three research investigations were included in this dissertation study. The first study was to determine the association between heart rate at rest and endothelium-dependent vasodilation as assessed by flow-mediated dilation (FMD) of the brachial artery. The primary findings from study 1 revealed an indirect association between heart rate and FMD through shear stimuli. The studies 2 and 3 sought to determine the association of regional cerebral perfusion with cardiovagal BRS and blood pressure components. A link between cardiovagal BRS and regional cerebral perfusion of the hippocampus was demonstrated in the study 2. This finding may add mechanistic insight to the relationship between impaired BRS and cognitive dysfunction. The primary finding from the study 3 revealed a significant relationship between peripheral pulsatile blood pressure components and regional cerebral perfusion of the hippocampus as well as anterior white matter. This finding highlights the importance of pulsatile pressure on cerebral vascular beds. Taken together, the overall findings from this dissertation study indicate the potential impacts of systemic hemodynamic factors on cerebral and peripheral perfusion. Future longitudinal studies in nondemented elderly and individuals with Alzheimer’s disease are warranted to reveal the causality of these associations.Kinesiology and Health Educatio

Cortical Autonomic Alterations with Hypertension

Objective: This study tested whether the medial prefrontal cortex (MPFC) is differentially involved in human cardiovagal control in normotensive (NT) versus hypertensive (HT) subjects. Design: Functional magnetic resonance imaging was combined with measures of heart rate (HR) and baroreflex sensitivity (BRS) during a 30-sec static handgrip (HG; 30% maximal strength) task. Results: Baseline HR was higher in HT (68±3 bpm) versus NT (59±2 bpm). Cardiovagal baroreflex sensitivity was lower in HT (6.8±1.7 msec/mniHg) versus NT (16.4±2.2 msec/mmHg). During HG, HR increased similarly in HT (2±1 bpm) and NT (4±1 bpm). In NT, the HR response was associated with deactivation in the MPFC. MPFC activity did not change in HT. In 11 of the total 23 subjects, HR increased \u3e 3 bpm and MPFC deactivation was correlated with the HR time course. Conclusions: Overall, hypertension appears to be equivalent to normotension in terms of the HR response to HG and the MPFC-HR associatio

Vibrational and stochastic resonances in driven nonlinear systems

Nonlinear systems are abundant in nature. Their dynamics have been extensively investigated due to their multidisciplinary applicability, ranging from all branches of physical and mathematical sciences to engineering as well as to life sciences and medicine. When driven by external forces, nonlinear systems can exhibit plethora of interesting and important properties - one of the most prominent being resonance. In the presence of a second, higher frequency, driving force, whether stochastic or deterministic/periodic, a resonance phenomenon arises that can generally be termed stochastic resonance or vibrational resonance. Operating a system in or out of resonance promises applications in several advanced technologies, such as the creation of novel materials at the nano, micro and macroscales including, but not limited to, materials having photonic band gaps, quantum control of atoms and molecules as well as miniature condensed matter systems. Motivated in part by these potential applications, this Theme Issue provides a concrete up-to-date overview of vibrational and stochastic resonances in driven nonlinear systems. It assembles state-of-the-art, original contributions on such induced resonances - addressing their analysis, occurrence, and applications from either the theoretical, numerical and experimental perspectives, or through combinations of these

Rest, Reactivity, and Recovery: A Psychophysiological Assessment of Borderline Personality Disorder

Difficulty regulating emotion is a cardinal feature of borderline personality disorder (BPD), yet little is known about the automatic psychophysiological processes involved in this phenotype. Inconsistent findings have emerged from studies that employed limited assessments (e.g., heart rate variability, skin conductance) of autonomic nervous system response to emotional contexts, and compared groups based on the presence or absence of BPD as a categorical diagnosis. This exploratory study assessed a comprehensive set of autonomic nervous system processes in 44 individuals (22 with BPD) at rest, in response to emotionally evocative stimuli, and during a subsequent recovery period. BPD was characterized with a dimensional measure of BPD symptom severity, as a well by categorical diagnosis. At baseline and across experimental tasks, higher heart rate was observed in those diagnosed with BPD compared to controls, and in those expressing greater BPD symptom severity. These effects, however, were fully mediated by differences in physical exercise. In contrast, during recovery from emotional activation, greater symptom severity predicted consistently higher levels of multiple sympathetic and parasympathetic processes compared to lower symptom severity. Overall, these findings suggest that the heart rate elevations sometimes observed in those diagnosed with BPD may be associated with individual and group differences in levels of physical exercise. Results further indicate that adaptive psychophysiological recovery responses following emotional challenge may be disrupted in proportion to BPD symptom severity, independently of exercise. Results highlight the utility of considering lifestyle factors and symptom severity in studies of emotional activation and regulation processes in BPD