Robert M. Kelsey

Presence of human friends and pet dogs as moderators of autonomic responses to stress in women

Autonomic responses were measured while 45 adult women performed a standard experimental stress task in the laboratory with only the experimenter present and 2 weeks later at home in the presence of a female friend, pet dog, or neither. Results demonstrated that autonomic reactivity was moderated by the presence of a companion, the nature of whom was critical to the size and direction of the effect. Ss in the friend condition exhibited higher physiological reactivity and poorer performance than subjects in the control and pet conditions. Ss in the pet condition showed less physiological reactivity during stressful tasks than Ss in the other conditions. The results are interpreted in terms of the degree to which friends and pets are perceived as evaluative during stressful task performance. Physiological reactivity was consistent across the laboratory and field settings.

Vagal rebound and recovery from psychological stress.

Objective To characterize cardiovascular recovery and examine the possible relationship of vagal activity and reflexes to risk for heart disease. Methods Subjects performed cold pressor and mental arithmetic tasks. Heart rate, heart period variability, and pre-ejection period were obtained for 1 minute before, during, and after each task (Experiment 1). In the second experiment, subjects performed a Stroop color-word task and a mental arithmetic task. Heart rate, heart period variability, blood pressure, and baroreflex sensitivity were obtained during the 5-minute baseline, task, and recovery periods (Experiment 2). Results In Experiment 1, heart rate during recovery was lower than baseline despite continued pre-ejection period shortening, whereas recovery heart period variability was higher than baseline. In Experiment 2, blood pressure increased throughout the session. However, recovery heart rate after mental arithmetic was lower than baseline heart rate, and heart period variability was higher during both recovery periods than during baseline. Vagal rebound, a sharp increase in variability in the first minute of recovery, was reduced in men in Experiment 1 and in individuals with a family history of cardiovascular disease in Experiment 2 and was associated with degree of change in baroreflex sensitivity between task and rest. Conclusions Cardiovascular recovery from stress is associated with increased vagal modulation despite residual sympathetic activation. Vagal rebound may be involved in mechanisms resetting the baroreflex sensitivity at the onset and offset of stress. Diminished vagal rebound during recovery from stress is associated with standard risk factors for cardiovascular disease. The results support an association between attenuated vagal reflexes and risk for cardiovascular disease.

Effects of Self-Deception, Social Desirability, and Repressive Coping on Psychophysiological Reactivity to Stress:

This study examined the relationship between psychophysiological reactivity to stress and three measures of defensiveness (self-deception, social desirability, and repressive coping). Physiological and psychological responses were recorded while subjects engaged in two consecutive, difficult mental arithmetic tasks. As expected, individuals high in self-deception appraised an upcoming novel mental arithmetic task as less threatening and were less psychophysiologically reactive during the task than low self-deceivers. In contrast, there were no effects for social desirability on task appraisal, but individuals high in social desirability were more physiologically reactive during the task. There were no effects for repressive coping, operationalized using a social desirability/anxiety typology, that were not accounted for by social desirability alone. The possible mechanisms underlying these effects are discussed.

Attitude accessibility as a Moderator of Autonomic Reactivity during Decision Making

Attitude functionality was assessed in 2 experiments examining attitude accessibility as a moderator of physiological responses during decision making. In Study 1, experimental Ss but not controls rehearsed attitudes toward novel objects (abstract paintings). Subsequently, all Ss made rapid preference judgments for pairs of the paintings. In Study 2, attitudes were rehearsed by all Ss toward 1 of 2 mutually exclusive sets of abstract paintings. During the subsequent decision-making task, half the Ss made rapid pairwise preference judgments for rehearsed abstract paintings and half for pairs from the unrehearsed set. Autonomic measures were recorded continuously throughout both experiments. As predicted, in both experiments less autonomic reactivity was evident during the criterion pairwise preference task for groups for whom attitude rehearsal was relevant to the criterion task.

Alpha-adrenergic receptor gene polymorphisms and cardiovascular reactivity to stress in Black adolescents and young adults: Genetic effects on cardiovascular reactivity

Cardiovascular reactivity to stress and α-adrenergic receptor (α-AR) function may contribute to the development of hypertension. As Black Americans have an increased risk of hypertension, we evaluated associations between α(1A) -AR (Arg492Cys), α(2A) -AR (-1291C/G), and α(2B) -AR (Ins/Del301-303) gene variants and cardiovascular reactivity in 500 normotensive Black youth. Heart rate, preejection period, total peripheral resistance, and blood pressure were measured during cold and psychological stress. The Arg492Cys polymorphism in the α(1A) -AR gene was associated with heart rate reactivity to stress, but the association depended on sex. The -1291C/G promoter polymorphism in the α(2A) -AR gene was associated with vascular reactivity to stress; vasoconstriction increased as a linear function of the number of copies of the variant G allele. Thus, specific associations emerged between genetic variations in α-Ars and cardiovascular reactivity in young Blacks.

Simultaneous acquisition of functional magnetic resonance images and impedance cardiography.

While simultaneous acquisition of electrocardiography (ECG) data during MRI is a widely used clinical technique, the effects of the MRI environment on impedance cardiography (ICG) data have not been characterized. We collected echo planar MRI scans while simultaneously recording ECG and thoracic impedance using carbon fiber electrodes and customized amplifiers. Here, we show that the key changes in impedance (dZ/dt) and features of the ECG waveforms are not obstructed during MRI. We present a method for ensemble averaging ICG/ECG signals collected during MRI and show that it performs comparably with signals collected outside the MRI environment. These results indicate that ICG can be used during MRI to measure stroke volume, cardiac output, preejection period, and left ventricular ejection time.

Environmental Stress and Myocardial Reactivity

This study tested aspects of a new theory (Kelsey, 1986) of the etiology and pathophysiology of primary Raynaud’s phenomenon. Raynaud’s phenomenon is defined as an episode of vasoconstriction, or vasospasm, of the small cutaneous arteries and arterioles in the extremities that causes a severe reduction in blood flow and a corresponding decrease in temperature in the skin of affected areas (Coffman & Davies, 1975; Gifford & Hines, 1957). These vasospastic episodes usually affect the fingers, causing them to turn cold, numb, and white; thus, Raynaud’s phenomenon is characterized as “episodic vasospastic ischemia of the digits” (Halperin & Coffman, 1979, p. 89). The phenomenon is further classified into primary and secondary forms. Primary Raynaud’s phenomenon, also known as Raynaud’s disease, refers to idiopathic manifestations of the disorder, whereas secondary Raynaud’s phenomenon refers to manifestations of the disorder that are symptomatic of an underlying primary disease, such as scleroderma.

Quantifying rapid changes in cardiovascular state with a moving ensemble average

MEAP, the moving ensemble analysis pipeline, is a new open-source tool designed to perform multisubject preprocessing and analysis of cardiovascular data, including electrocardiogram (ECG), impedance cardiogram (ICG), and continuous blood pressure (BP). In addition to traditional ensemble averaging, MEAP implements a moving ensemble averaging method that allows for the continuous estimation of indices related to cardiovascular state, including cardiac output, preejection period, heart rate variability, and total peripheral resistance, among others. Here, we define the moving ensemble technique mathematically, highlighting its differences from fixed-window ensemble averaging. We describe MEAPs interface and features for signal processing, artifact correction, and cardiovascular-based fMRI analysis. We demonstrate the accuracy of MEAPs novel B point detection algorithm on a large collection of hand-labeled ICG waveforms. As a proof of concept, two subjects completed a series of four physical and cognitive tasks (cold pressor, Valsalva maneuver, video game, random dot kinetogram) on 3 separate days while ECG, ICG, and BP were recorded. Critically, the moving ensemble method reliably captures the rapid cyclical cardiovascular changes related to the baroreflex during the Valsalva maneuver and the classic cold pressor response. Cardiovascular measures were seen to vary considerably within repetitions of the same cognitive task for each individual, suggesting that a carefully designed paradigm could be used to capture fast-acting event-related changes in cardiovascular state.