How are tonic and phasic cardiovascular changes related to central motor command?

Anticipatory cardiac deceleration estimates cognitive performance in virtual reality beyond tonic heart period and heart period variability

Anticipatory cardiac deceleration is the lengthening of heart period before an expected event. It appears to reflect preparation that supports rapid action. The current study sought to bolster anticipatory deceleration as a practical and unique estimator of performance efficiency. To this end, we examined relationships between deceleration and virtual reality performance under low and high time pressure. Importantly, we investigated whether deceleration separately estimates performance beyond basal heart period and basal high-frequency heart rate variability (other vagally influenced metrics related to cognition). Thirty participants completed an immersive virtual reality (VR) cognitive performance task across six longitudinal sessions. Anticipatory deceleration and basal heart period/heart period variability were quantified from electrocardiography collected during pre-task anticipatory countdowns and baseline periods, respectively. At the between-person level, we found that greater anticipatory declaration was related to superior accuracy and faster response times (RT). The relation between deceleration and accuracy was stronger under high relative to low time pressure, when good performance requires greater efficiency. Findings for heart period and heart period variability largely converge with the prior literature, but importantly, were statistically separate from deceleration effects on performance. Lastly, deceleration effects were detected using anticipatory periods that are more practical (shorter and more intermittent) than those typically employed. Taken together, findings suggest that anticipatory deceleration is a unique and practical correlate of cognitive-motor efficiency apart from heart period and heart period variability in virtual reality.

Host in the machine: A neurobiological perspective on psychological stress and cardiovascular disease

Psychological stress still attracts scientific, clinical, and public interest because of its suspected connection to health, particularly cardiovascular health. Psychological stress is thought to arise from appraisal processes that imbue events and contexts with personal significance and threat-related meaning. These appraisal processes are also thought to be instantiated in brain systems that generate and control peripheral physiological stress reactions through visceral motor (brain-to-body) and visceral sensory (body-to-brain) mechanisms. In the short term, physiological stress reactions may enable coping and adaptive action. Among some individuals, however, the patterning of these reactions may predict or contribute to pathology in multiple organ systems, including the cardiovascular system. At present, however, we lack a precise understanding of the brain systems and visceral control processes that link psychological appraisals to patterns of stress physiology and physical health. This understanding is important: A mechanistic account of how the brain connects stressful experiences to bodily changes and health could help refine biomarkers of risk and targets for cardiovascular disease prevention and intervention. We review research contributing to this understanding, focusing on the neurobiology of cardiovascular stress reactivity and cardiovascular health. We suggest that a dysregulation of visceral motor and visceral sensory processes during stressful experiences may confer risk for poor cardiovascular health among vulnerable individuals. We further describe a need for new interpretive frameworks and markers of this brain-body dysregulation in cardiovascular behavioral medicine. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

An interoceptive illusion of effort induced by false heart-rate feedback

Interoception, or the sense of the internal state of the body, is key to the adaptive regulation of our physiological needs. Recent theories contextualize interception within a predictive coding framework, according to which the brain both estimates and controls homeostatic and physiological variables, such as hunger, thirst, and effort levels, by orchestrating sensory, proprioceptive, and interoceptive signals from inside the body. This framework suggests that providing false interoceptive feedback may induce misperceptions of physiological variables, or "interoceptive illusions." Here we ask whether it is possible to produce an illusory perception of effort by giving participants false acoustic feedback about their heart-rate frequency during an effortful cycling task. We found that participants reported higher levels of perceived effort when their heart-rate feedback was faster compared with when they cycled at the same level of intensity with a veridical feedback. However, participants did not report lower effort when their heart-rate feedback was slower, which is reassuring, given that failing to notice one's own effort is dangerous in ecologically valid conditions. Our results demonstrate that false cardiac feedback can produce interoceptive illusions. Furthermore, our results pave the way for novel experimental manipulations that use illusions to study interoceptive processing.

The value of the isometric hand-grip test--studies in various autonomic disorders

Time-related methodological differences have confounded the value of isometric hand-grip (IHG) exercise as a test of sympathetic function. This study examines the blood pressure response to IHG in 71 normal subjects and 76 dysautonomic patients and compares it with the tilt table test. All participants were supine and performed IHG at 30% of maximum contraction for 5 min. Change in diastolic blood pressure (DBP) was the most sensitive and specific measurement in diagnosing abnormals. The multivariate group by time (1-5 min) effect was significant (F = 10.14, p < 0.001) with 5 min as the most important time measurement (Wilk's lambda = 0.70, p < 0.001). The DPB rise for normals was 25.15 +/- 1.31 mmHg (mean +/- SE), range 22.55-27.76 mmHg, with a sensitivity of 78.95% and a specificity of 71.83%. A multivariate analysis of variance showed intraindividual reproducibility of nine normals over four trials (F = 0.950, p > 0.25). Gender and grip strength were additional important variables. In comparison, the tilt table test demonstrated a sensitivity of 82.76% and a specificity of 73.68%. Isometric hand-grip is therefore a specific, sensitive, reproducible, simple and non-invasive test of sympathetic function with relatively well-studied reflex pathways. Its sensitivity and specificity compare favourably with the tilt table test. It should be incorporated in routine autonomic testing.

Is it important that the mind is in a body? Inhibition and the heart

The hypothesis is advanced that certain inhibitory processes necessarily involve autonomic adjustments. Such adjustments would represent a constraint on information processing imposed by the location of the mind in a body. Evidence is reviewed showing that motoric inhibition is related to a transient delay in heartbeat generation. The delay is shown to further depend upon when inhibition occurs in the cardiac cycle. It is argued that this form of interaction between central and autonomic nervous system processing may be common. Central nervous system processes that may control inhibition and integrate information processing with motoric and autonomic processes are discussed.