Biomedical subjects

Julian F Thayer

Publications and source records attributed to Julian F Thayer.

At least 37 records · Page 2Linked to original sources

PubMed2004

Hostility and distraction have differential influences on cardiovascular recovery from anger recall in women.

This study investigated the relation of dispositional hostility to cardiovascular reactivity during an anger-recall task and of hostility and distraction to posttask recovery in 80 healthy women (ages 18-30). Half were randomly assigned to distraction during recovery. Hostility predicted slower systolic blood pressure and preejection period during recovery. Distraction was related to faster cardiac recovery, higher high-frequency (HF) power, lower low-frequency (LF) power and LF:HF ratios, and lower state anger and rumination during recovery. These results indicate deleterious influences of hostility on cardiovascular recovery but not during anger recall. The findings also show beneficial effects of distraction in expediting cardiovascular recovery, possibly through reducing rumination and anger.

Adolescent↗

PubMed2004

Sleep deprivation and hemispheric asymmetry for facial recognition reaction time and accuracy.

We investigated the processing of emotional stimuli during a non-sleep-deprived state and following sleep deprivation in 36 right-handed men. Using the visual half-field technique, cartoon line drawings of emotional facial expressions were flashed on a computer screen for 250 msec. The participants were instructed to remember the content of the picture seen and to recognize it among nine alternatives shown immediately after the display of a single picture. Compared to the nondeprived condition, response latencies increased and accuracy decreased in sleep deprivation. Moreover, response latencies indicated that the performance of the right hemisphere deteriorated more following sleep deprivation than did the performance of the left hemisphere. The results also showed that hemispheric preference (for response latencies and response accuracy) tended to favour the left hemisphere when the participants were tested during sleep deprivation.

Adult↗

PubMed2004

Kullback-Leibler clustering of continuous wavelet transform measures of heart rate variability.

Power spectral analysis of beat-to-beat heart rate variability (HRV) has provided a useful means of understanding the interplay between autonomic and cardiovascular functionality. Despite their utility, commonly employed frequency-domain techniques are limited in their prerequisite for stationary signals and their inability to account for temporal changes in the power spectral and/or frequency properties of signals. The purpose of this study is to develop an algorithm that utilizes continuous wavelet transform (CWT) parameters as inputs to a Kohonen self-organizing map (SOM), providing a method of clustering subjects with similar wavelet transform signatures. Continuous interbeat-intervals were recorded (Portapres monitor at 200 Hz) during a perception of affect test in 79 African-American volunteers (ages 21-83), where after a 5-min baseline, participants evaluated emotional expressions in sentences and pictures of faces, followed by a 5-min recovery. Individual HRV biosignals from each session were pre-processed (artifact replacement and signal resampling at 2 Hz) and a CWT was applied (db9 wavelet basis function over 32 scales). Standard deviations of resulting wavelet coefficients at each scale were calculated, normalized, and used as inputs into a SOM with Kullback-Leibler divergence as the dissimilarity measure used for clustering. Differences in subject demographics between two final clusters were assessed via two-independent-groups t-tests or chi-square or Fisher's exact tests of contingency tables. Significant differences were found for age, initial systolic blood pressure, smoking status, and mean s.d. of coefficients in the high frequency band (0.15-0.4 Hz). These findings may have clinical significance and the developed algorithm provides an alternative means of analyzing HRV data originating from populations with complex covariates.

Adult↗

PubMed2003

Effect of angiotensin-converting enzyme insertion/deletion polymorphism DD genotype on high-frequency heart rate variability in African Americans.

Seventy-nine African-American participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) pilot study were genotyped for the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and had spectral power of their high-frequency (HF) heart rate variability (HRV) determined by fast-Fourier transformation. HF HRV was highest in II, intermediate in ID, and lowest in DD (II vs DD, p <0.043) genotypes, thus making an association of the ACE I/D DD genotype with decreased HF HRV that is consistent with the hypothesis that the DD genotype confers susceptibility to increased cardiovascular risk. The urban African-American population we studied had a particularly high cardiovascular risk, and these findings suggest that ACE I/D genotypes may modify that risk.

Adrenergic beta-Antagonists↗

PubMed2003

Reduced heart rate variability in chronic alcohol abuse: relationship with negative mood, chronic thought suppression, and compulsive drinking.

BACKGROUND: Previous research suggests that heart rate variability (HRV) may be an important factor in various maladaptive psychological conditions. METHODS: This study was conducted to investigate vagal tone assessed as tonic vagally mediated heart rate variability in alcoholic (n = 49) and control subjects (n = 45). RESULTS: Alcoholic subjects had faster heart rate and lower preimaginary exposure levels of HRV compared with the control group. An increase in HRV was observed in the alcoholic group when subjects were exposed to an imaginary alcohol script. Tonic HRV was found to be related inversely to negative mood and chronic thought suppression and positively to positive mood. Furthermore, the compulsive subscale of the Obsessive Compulsive Drinking Scale (OCDS) was inversely related to HRV during the imaginary alcohol exposure. CONCLUSIONS: It is concluded that the findings are in agreement with the neurovisceral integration model of affective regulation, which claims that dysfunctional psychologic states are rooted in an impaired inhibitory mechanism that is associated with low HRV.

Adult↗

PubMed2003

Vagal influence on working memory and attention.

The aim of the present study was to investigate the effect of vagal tone on performance during executive and non-executive tasks, using a working memory and a sustained attention test. Reactivity to cognitive tasks was also investigated using heart rate (HR) and heart rate variability (HRV). Fifty-three male sailors from the Royal Norwegian Navy participated in this study. Inter-beat-intervals were recorded continuously for 5 min of baseline, followed by randomized presentation of a working memory test (WMT) based on Baddeley and Hitch's research (1974) and a continuous performance test (CPT). The session ended with a 5-min recovery period. High HRV and low HRV groups were formed based on a median split of the root mean squared successive differences during baseline. The results showed that the high HRV group showed more correct responses than the low HRV group on the WMT. Furthermore, the high HRV group showed faster mean reaction time (mRT), more correct responses and less error, than the low HRV group on the CPT. Follow-up analysis revealed that this was evident only for components of the CPT where executive functions were involved. The analyses of reactivity showed a suppression of HRV and an increase in HR during presentation of cognitive tasks compared to recovery. This was evident for both groups. The present results indicated that high HRV was associated with better performance on tasks involving executive function.

Adult↗

PubMed2003

Craving for alcohol and pre-attentive processing of alcohol stimuli.

The present study was designed to test the hypothesis of unconscious attending to alcohol-related information in alcoholics experiencing a high level of craving for alcohol. Subjects included a group of alcoholics (n=34) divided by a median split on a craving measure into two groups labeled as 'high craving' (n=18) and 'low craving' (n=16) alcoholics, and a non-alcoholic control group (n=39). The cardiovascular reactions of these groups were compared after their exposure to masked and unmasked alcohol and control stimuli. As expected the 'high craving' alcoholics showed an immediate heart rate deceleration after exposure to masked and non-consciously accessible alcohol pictures. The 'high craving' alcoholics reported a small but significant increase in difficulty resisting a drink after exposure to masked alcohol pictures. When the alcohol pictures were presented unmasked a significant increase was found in both high and low craving alcoholics on consciously expressed urges, fidgeting and reduced coping with temptation to drink. The 'high craving' alcoholics had lower tonic heart rate variability compared to the control group and the level of craving was positively associated with salivation during the exposure to all picture types. The findings generally support the psychobiological theory of craving, which suggests that the uncontrollability of the craving experience is rooted in unconscious processing of drug-related information.

Adult↗

PubMed2003

Heart rate response is longer after negative emotions than after positive emotions.

Summary. Recent ambulatory findings showing comparable cardiovascular effects of positive and negative emotions are not consistent with the assumed etiological role of negative affect in stress-related diseases. We tested the hypothesis that regardless of initial reactivity, responses associated with negative emotions would be prolonged compared to responses associated with positive emotions. During 8 h, 33 healthy subjects from a general population reported their emotional arousal, emotional valence and physical activity and recorded their heart rates (HR) after a beep at each 60th min ('initial HR'; T0), followed by two 'prolonged activation' recordings, respectively 5 min later (T1) and 10 min later (T2). While emotional arousal and activity predicted initial HR, prolonged activation at T1 was solely predicted by emotional valence (negative affect) at T0, independent of emotional recovery. The results lend support to the hypothesis that cardiovascular activation after negative emotions last longer than after positive emotions. This finding is consistent with the view that prolonged activation, and not so much reactivity, might be a mechanism underlying the etiological role of negative emotions ('stress') in somatic disease. Perseverative cognition (worry, rumination) might be responsible for this prolonged activation.

Adolescent↗

PubMed2003

Central and autonomic nervous system integration in emotion.

Emotions involve physiological responses that are regulated by the brain. The present paper reviews the empirical literature on central nervous system (CNS) and autonomic nervous system (ANS) concomitants of emotional states, with a focus on studies that simultaneously assessed CNS and ANS activity. The reviewed data support two primary conclusions: (1) numerous cortical and subcortical regions show co-occurring activity with ANS responses in emotion, and (2) there may be reversed asymmetries on cortical and subcortical levels with respect to CNS/ANS interrelations. These observations are interpreted in terms of a model of neurovisceral integration in emotion, and directions for future research are presented.

Affect↗

PubMed2003

Attentional and physiological characteristics of patients with dental anxiety.

Twenty patients with dental anxiety were investigated while seated in a dental chair in a dental clinic. Heart rate (HR), heart rate variability (HRV), and skin conductance level (SCL) were recorded while the patients were exposed to scenes of dental treatment as well as a Stroop attentional task. Results showed an attentional bias with longer manual reaction times (RT's) to the incongruent compared to the congruent color words as well as the threat compared to the neutral words. Longer RT's to the incongruent and the threat words were found in the low HRV patients compared to the high HRV patients. Furthermore, all patients showed an increase in HR during exposure and the Stroop task compared to baseline. The HRV showed a decrease during the exposure and the Stroop task compared to baseline. HR and HRV did not differ between exposure and the Stroop task. Moreover, HR and HRV did not return to baseline levels during the recovery period. The SCL showed an increase from baseline to exposure, from exposure to the Stroop task and a decrease in the recovery phase. Results showed the importance of vagal cardiac control in attentional, emotional, and physiological processes in patients suffering from dental fear.

Adult↗

PubMed2003

Preattentive processing of alcohol stimuli.

An experiment was conducted to test the automatic analysis of briefly presented alcohol stimuli in alcohol-dependent individuals. Alcoholics and controls were exposed to four different conditions: two brief (30 ms) and two long (130 ms) exposure conditions, each containing alcoholic and non-alcoholic pictures. Heart rate (HR) interbeat intervals were recorded and phasic cardiac responses assessed. Alcoholics had a stronger initial HR deceleration after exposure to masked alcohol slides compared with masked control slides, indicating a preattentive analysis of alcohol stimuli. This initial HR deceleration in the masked condition suggests an automatic attentional focusing to degraded alcohol cues. No such attentional effect was found when the pictures were presented unmasked and were clearly perceived. The implication of these results for the understanding of relapse in addictive behavior is discussed.

Alcohol Drinking↗

PubMed2003

The rhythm of the heart in the blink of an eye: emotion-modulated startle magnitude covaries with heart rate variability.

Emotion-modulated startle is a robust phenomenon that has been demonstrated in a wide range of experimental situations. Similarly, heart rate variability (HRV) has been associated with a diverse range of processes including affective and attentional regulation. The present study sought to examine the relationship between these two important measures of affective behavior. Ninety female participants viewed pleasant, neutral, and unpleasant pictures while exposed to acoustic startle stimuli. The eyeblink startle was recorded both during the affective foregrounds and during intertrial intervals. HRV was assessed during a resting baseline and relationships between HRV and startle magnitudes examined. Results indicated that resting HRV was inversely related to startle magnitude during both intertrial intervals and affective foregrounds. In addition, the participants with the highest HRV showed the most differentiated emotion-modulated startle effects, whereas those with the lowest HRV, compared to those with the highest HRV, showed significantly potentiated startle to neutral foregrounds and marginally potentiated startle to pleasant foregrounds. The findings are consistent with models that posit that prefrontal cortical activity modulates subcortical motivation circuits. These results have important implications for the use of startle probe methodology and for HRV in the study of emotional regulation and dysregulation.

Adult↗

PubMed2003

Relationships among spectral measures of baroreflex sensitivity and indices of cardiac vagal control.

Traditionally baroreflex sensitivity (BRS) has been assessed with pharmacological approaches such as phenylephrine infusion. Recently, non-invasive approaches using spectral analytic techniques have been employed to combine heart rate and blood pressure variability parameters to estimate BRS (the alpha index). Some authors have argued that BRS assessed at different frequencies of cardiovascular variabilities provide identical information and they should be combined into a single index of BRS based on total variability. The present study examined the relationship between BRS assessed using low, high, and total heart rate and blood pressure variabilities, and indices of cardiac vagal control assessed by standard spectral measures. Participants were 105 older male and female African-Americans who were part of the Healthy Aging In Nationally Diverse Longitudinal Samples (HANDLS) Study. Heart rate and blood pressure variabilities (HRV and BPV) were assessed using the Fast-Fourier Transform (FFT). The alpha index was computed as the square root of the ratio of low, high, or the mean of low and high frequency heart rate variability and the corresponding frequency ranges for systolic blood pressure variability. Correlations examining the relationships among BRS and various (e.g. log, normalized) indices of high frequency heart period variability (HF) were calculated for the total sample and by gender. Results indicated that the different BRS indices do not have the same relationship to all indices of HF. The results suggest that an aggregation of the power across bands is problematic at best, and indicates the need to examine the various frequency components separately.

Adult↗

PubMed2003

A compact ECG R-R interval, respiration and activity recording system.

An ECG R-R interval, respiration and activity recording system has been developed for monitoring variability of heart rate and respiratory frequency during daily life. The recording system employs a variable gain instrumentation amplifier, an accelerometer, a low power 8-bit single-chip microcomputer and a 1024 KB EEPROM. It is constructed on three ECG chest electrodes. The R-R interval and respiration are detected from the ECG. Activity during walking and running is calculated from an accelerator. The detected data are stored in an EEPROM and after recording, are downloaded to a desktop computer for analysis.

Acceleration↗

PubMed2003

Ambulatory monitoring of cardiovascular responses during behavioral modification of an aggressive dog.

Previous work from our lab has used the Dutch Ambulatory Monitoring System (AMS) to assess the cardiovascular responses and motility of large free-ranging species (e.g. horses). To further examine the utility of using the AMS with non-humans, a study investigating the heart rate (HR) and heart period variability (HRV) of a large canine undergoing behavioral modification therapy was undertaken. This treatment emulated a restraint and tactile pressure technique that has previously been used in horses. Cardiovascular responses and motility were continuously measured pre-treatment (exposure to a stimulus dog), during treatment (in-box), and post-treatment. The treatment consisted of placing the dog in a 110 cm (long) by 45 cm (wide) by 102 cm (height) wooden box that only covered the animals' torso and legs and allowed the head to be free. Once the dog was in the box, the body was covered with a lightweight material (grain product) to effect restraint and tactile pressure, which was followed by a repeat exposure to the stimulus animal. Results indicated decreased heart rate and an increased HRV during the intervention as compared to baseline with indices of motility changing in the expected directions. Estimates of respiratory frequency derived from the autoregressive spectral analysis indicated changes in respiration did not account for the cardiovascular effects. In conclusion, tactile pressure and restraint may be an important tool for behavioral modification in both humans and animals, and the AMS is a useful tool for collecting cardiovascular data on a variety of species in a great many contexts.

Acceleration↗

PubMed2003

A microcomputer-based daily living activity recording system.

A new daily living activity recording system has been developed for monitoring health conditions and living patterns, such as respiration, posture, activity/rest ratios and general activity level. The system employs a piezoelectric sensor, a dual axis accelerometer, two low-power active filters, a low-power 8-bit single chip microcomputer and a 128 MB compact flash memory. The piezoelectric sensor, whose electrical polarization voltage is produced by mechanical strain, detects body movements. Its high-frequency output components reflect body movements produced by walking and running activities, while the low frequency components are mainly respiratory. The dual axis accelerometer detects, from body X and Y tilt angles, whether the patient is standing, sitting or lying down (prone, supine, left side or right side). The detected respiratory, behavior and posture signals are stored by the compact flash memory. After recording, these data are downloaded to a desktop computer and analyzed.

Acceleration↗

PubMed2003

Genetic and environmental influences on blood pressure and pulse pressure among adult African Americans.

OBJECTIVE: The purpose of the present study was to identify sources of variability for systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) in a sample of adult African-American twins. DESIGN: The classic twin design was employed to examine genetic and environmental sources of variance in the outcome measures of interest. PARTICIPANTS: Participants were 143 (71 MZ and 72 DZ) same-sex, intact twin pairs (mean age = 49.87 years; SD 13.62), who took part in the Carolina African-American Twin Study of Aging (CAATSA). MAIN OUTCOME MEASURES: Outcome measures of interest included SBP and DBP, and PP. RESULTS: For older twins, heritabilities were .52 for SBP, .36 for DBP, and .14 for PP. However, for younger twins, heritabilities were .44 for SBP, .27 for DBP, but no genetic influence on PP was observed. CONCLUSION: The results indicate that genetic factors are a significant source of variance in hemodynamic indices, and also suggest that, with advancing age, genetic factors play an increasing role in determining blood pressure and PP in this population.

Adult↗

PubMed2002

Stop that! Inhibition, sensitization, and their neurovisceral concomitants.

There is increasing evidence that the behavior of living systems can be conceptualized as a self-organizing dynamical system. Moreover, evidence suggests that inhibitory processes give these systems the flexibility that is necessary for efficient functioning in the face of changing environmental demands. The process of sensitization can be conceived as a breakdown of inhibitory neural processes that can lead to maladaptive, perseverative behavior. In this paper we describe a model of inhibition and sensitization from a dynamical systems perspective. We show that inhibition is important for adaptive behavior across a number of levels of system functioning. Using our work on attention, emotion, and anxiety disorders we show the importance of both central - for example gamma-aminobutyric acid (GABA)-ergic - and peripheral - for example heart rate variability (HRV) - inhibitory processes and how they may be linked by a network of neural structures that guide the organism from one state of relative stability to another.

Humans↗