Orienting in a defensive world: mammalian modifications of our evolutionary heritage. A Polyvagal Theory

Pathways to PTSD, part II: Sexually abused children

OBJECTIVE

The goal of this research was to develop and test a prospective model of posttraumatic stress symptoms in sexually abused children that includes pretrauma, trauma, and disclosure-related pathways.

METHOD

At time 1, several measures were used to assess pretrauma variables, trauma variables, and stress reactions upon disclosure for 156 sexually abused children ages 8 to 13 years. At the time 2 follow-up (7 to 36 months following the initial interview), the children were assessed for posttraumatic stress disorder (PTSD) symptoms.

RESULTS

A path analysis involving a series of hierarchically nested ordinary least squares multiple regression analyses indicated three direct paths to PTSD symptoms: avoidant coping, anxiety/arousal, and dissociation, all measured during or immediately after disclosure of sexual abuse. Additionally, age and gender predicted avoidant coping, while life stress and age at abuse onset predicted symptoms of anxiety/arousal. Taken together, these pathways accounted for approximately 57% of the variance in PTSD symptoms.

CONCLUSIONS

Symptoms measured at the time of disclosure constitute direct, independent pathways by which sexually abused children are likely to develop later PTSD symptoms. These findings speak to the importance of assessing children during the disclosure of abuse in order to identify those at greatest risk for later PTSD symptoms.

Cardiac Vagal Tone, defensiveness, and motivational style

Cardiac Vagal Tone has been proposed as a stable biological marker for the ability to sustain attention and regulate emotion [Porges, Monographs of the Society for Research in Child Development 59 (1994) 167-186]. Vagal tone is a physiological index of parasympathetic nervous system influence on the heart that has predicted a number of emotional behaviors and styles in infants, children, and adults. Little research, however, has sought to explore the link between vagal tone and established variables relating to personality and self-regulation. In this study, vagal tone was collected during 5-min baseline, stress, and recovery periods. Subjects (n = 98) also completed a short form of the Marlowe-Crowne Social Desirability Scale, the Behavioral Activation and Behavioral Inhibition Scales, the Taylor Manifest Anxiety Scale, the Self-Consciousness Scale, and the Openness to Experience subscale of the Five Factor Personality Inventory. Poorer modulation for vagal tone was associated with greater social anxiety, while lower vagal tone across recording periods was associated with greater defensiveness and lower behavioral activation sensitivity.

Sudarshan Kriya yogic breathing in the treatment of stress, anxiety, and depression: part I-neurophysiologic model

Mind-body interventions are beneficial in stress-related mental and physical disorders. Current research is finding associations between emotional disorders and vagal tone as indicated by heart rate variability. A neurophysiologic model of yogic breathing proposes to integrate research on yoga with polyvagal theory, vagal stimulation, hyperventilation, and clinical observations. Yogic breathing is a unique method for balancing the autonomic nervous system and influencing psychologic and stress-related disorders. Many studies demonstrate effects of yogic breathing on brain function and physiologic parameters, but the mechanisms have not been clarified. Sudarshan Kriya yoga (SKY), a sequence of specific breathing techniques (ujjayi, bhastrika, and Sudarshan Kriya) can alleviate anxiety, depression, everyday stress, post-traumatic stress, and stress-related medical illnesses. Mechanisms contributing to a state of calm alertness include increased parasympathetic drive, calming of stress response systems, neuroendocrine release of hormones, and thalamic generators. This model has heuristic value, research implications, and clinical applications.

Biological sensitivity to context: II. Empirical explorations of an evolutionary–developmental theory

In two studies comprising 249 children and their families, the authors utilized secondary, exploratory data analyses to examine Boyce and Ellis' (this issue) evolutionary-developmental theory of biological sensitivity to context. The theory proposes that individual differences in stress reactivity constitute variation in susceptibility to environmental influence, both positive and negative, and that early childhood exposures to either highly protective or acutely stressful environments result in heightened reactivity. In Study 1, 127 3- to 5-year old children were concurrently assessed on levels of support/adversity in home and preschool environments and on cardiovascular reactivity to laboratory challenges. In Study 2, 122 children were prospectively assessed on familial stress in both infancy and preschool and on autonomic and adrenocortical reactivity to laboratory challenges at age 7. In both studies, a disproportionate number of children in supportive, low stress environments displayed high autonomic reactivity. Conversely, in Study 2, a relatively high proportion of children in very stressful environments showed evidence of heightened sympathetic and adrenocortical reactivity. Consistent with the evolutionary-developmental theory, the exploratory analyses also generated the testable hypothesis that relations between levels of childhood support/adversity and the magnitude of stress reactivity are curvilinear, with children from moderately stressful environments displaying the lowest reactivity levels in both studies.

Vagal withdrawal to a sad film predicts subsequent recovery from depression

Cardiac vagal tone, as indexed by abnormalities in the level and/or reactivity of respiratory sinus arrhythmia (RSA), has been related to psychiatric impairment, including risk for depression. Longitudinal studies of depression have focused on RSA levels and have found mixed support for the hypothesis that low RSA levels predict a more pernicious course of depression. The current investigation focuses on the relation between RSA reactivity and the course of depression. We measured depressed persons' RSA reactivity to sadness-, fear-, and amusement-inducing emotion films and reassessed participants' diagnostic status 6 months later. Depressed persons who exhibited a higher degree of vagal withdrawal to the sad film were more likely to recover from depression. Implications for the study of RSA in depression are discussed.

Coparenting, family-level processes, and peer outcomes: the moderating role of vagal tone

This article examines the relationship between coparenting and family-level processes during preschool and peer relationship outcomes in middle childhood, and the hypothesis that children's ability to regulate emotion (as indexed by basal vagal tone and the ability to suppress vagal tone) may moderate this relationship. We predicted that high vagal tone and a greater ability to suppress vagal tone would buffer children from the effects of negative coparenting and family processes. Results indicated that hostile-withdrawn coparenting predicted higher levels of conflicted play and lower levels of positive peer conversation. Vagal suppression also moderated the relationship between hostile-withdrawn coparenting and peer conflict. For children who were unable to suppress vagal tone, hostile-withdrawn coparenting was associated with higher levels of peer conflict, while for children who were able to suppress vagal tone there was no relationship hostile-withdrawn coparenting and peer conflict. The relationship between hostile-withdrawn coparenting and positive peer conversation was also moderated by children's ability to suppress vagal tone. For children who were unable to suppress vagal tone, there was no relationship between hostile-withdrawn coparenting and positive peer conversation, while for those who were able to suppress vagal tone, hostile-withdrawn coparenting was associated with less positive peer conversation. Cohesive family-level processes also predicted positive conversation in play at age 9 after controlling for positive conversation at age 5; however, this relationship was not moderated by vagal suppression. Basal vagal tone also did not function as a moderator of relations between hostile-withdrawn coparenting and peer play. Results are discussed in terms of the effects of negative coparenting on children with different patterns of modulating physiological arousal.

Probing the psychophysiology of the airways: physical activity, experienced emotion, and facially expressed emotion

This article reviews research on airway reactivity in health and asthma within a psychophysiological context, including the effects of physical activity, emotion induction, and manipulation of facial expression of emotion. Skeletal muscle activation leads to airway dilation, with vagal withdrawal being the most likely mechanism. Emotional arousal, in particular negative affect, leads to airway constriction, with evidence for a vagal pathway in depressive states and ventilatory contributions in positive affect. Laboratory-induced airway responses covary with reports of emotion-induced asthma and with lung function decline during negative mood in the field. Like physical activity, facial expression of emotion leads to airway dilation. However, these effects are small and less consistent in posed emotional expressions. The mechanisms of emotion-induced airway responses and potential benefits of emotional expression in asthma deserve further study.

Autonomic response patterns observed during the performance of an attention-demanding task in two groups of children with autistic-type difficulties in social adjustment

Two groups of children with autistic-type behavior problems were compared to a group of normal children with respect to their autonomic response patterns observed during the performance of an attention-demanding task. Heart rate, blood pressure, and respiratory activity were measured during periods of rest and of task performance. Applying a quantitative model of the baroreflex, we were able to demonstrate qualitative differences among the groups with respect to their vagally controlled response patterns, whereas sympathetic responsiveness did not differ. In terms of our model, the groups with autistic-type behavior showed a decrease in central vagal tone during task performance, while vagal gain appeared to be unaffected or even increased. In contrast, the children in the control group showed the expected pattern of a decrease in vagal gain while vagal tone appeared to be increased. Implications of our findings are discussed in the light of Damasio's somatic marking hypothesis.

Early detection of core deficits in autism

The goal of this review of the research literature is to discuss approaches to the early detection of autism in infancy. Early detection would enable diagnoses to be made before 18 months of age rather than at 24-30 months, the age where diagnoses start to be made now. After summarizing the criteria for a deficit to be considered "core" to the disorder, the literature on research strategies used in early detection is examined. In order to guide the design of future studies, the review then turns to an overview of what is known about the processes of early social development in typically developing children that underlie the domains in which core deficits are manifested in young children with autism. The social domains covered in the review are those that show development in typically developing infants below 18 months of age: dyadic interaction and imitation; emotion discrimination; and attachment. The review concludes that all of these areas are worthy of investigation in young children, particularly those at higher risk of showing some of the core deficits of autism such as the infant siblings of children with autism.

Respiratory Sinus Arrhythmia During Stress Predicts Resting Respiratory Sinus Arrhythmia 3 Years Later in a Pediatric Sample

The author examined whether respiratory sinus arrhythmia (RSA) responses to stress predicted resting RSA approximately 3 years later in children and adolescents. A total of 149 children and adolescents (49% girls and women, 44% African Americans) participated in 2 laboratory protocols approximately 3 years apart. RSA reactivity during tasks was consistent within participants across tasks during each session. Resting RSA at Visit 1 explained 17% of the variance in resting RSA at Visit 2 when body mass index, duration between visits, race, gender, and age were controlled for. Visit 1 RSA reactivity explained an additional 5% of the variance in resting RSA at Visit 2. The positive relationship between Visit 1 reactivity and Visit 2 resting levels suggests that larger decreases in RSA during stress predicted lower resting RSA. Conversely, increases in RSA during stress were associated with higher resting RSA an average of 3 years later.

Cardiac reactivity is associated with changes in negative emotion in 24-month-olds

Despite the call for multilevel observation of negative affect, including multiple physiological systems, too little empirical research has been conducted in infants and young children, and physiology-affect associations are not consistently reported. We examined changes in heart rate, respiratory sinus arrhythmia, and preejection period in 24-month-olds across four increasingly challenging, emotion-eliciting tasks. We predicted that changes in cardiac reactivity would be systematically related to changes in negative affect. Results largely support the predictions with one important exception. With increasing distress across the tasks, HR increased and RSA decreased. However, no significant changes in PEP were observed. HR was associated with negative affect during all tasks, and changes in HR were related to changes in negative affect. PEP and negative affect were associated, but only marginally so. Within-subject analyses confirmed the predicted associations. Finally, the associations between physiology and negative affect were different for boys and girls. We discuss these results in the context of implications for future research on cardiac-affect associations in young children.

Vagal regulation and emotional intensity predict children's sleep problems

We examined the role of children's emotional intensity and vagal functioning in predicting sleep problems in healthy elementary school-aged children. Children's dispositional emotionality was examined via parent report, and their vagal regulation was assessed via respiratory sinus arrhythmia (RSA) during a baseline and a reaction time (RT) task. Sleep problems were examined through both child reports, and home monitoring with wrist actigraphs for four consecutive nights. Increased emotional intensity was predictive of a reduced amount of sleep and increased night activity. Less apt vagal regulation, characterized by lower levels of RSA suppression to the RT task, was predictive of increased sleep problems as assessed through both subjective and actigraphy-based measures of sleep. Results indicate that children's emotionality and regulation predict unique variance in the amount and quality of children's sleep, and suggest that they may underlie, at least in part, sleep disturbances in healthy children.

A new test for autonomic cardiovascular and neuroendocrine responses in diabetes mellitus: evidence for early vagal dysfunction

AIMS/HYPOTHESIS

Diabetic autonomic neuropathy affects many physiological systems, producing a variety of important clinical manifestations. It is associated with high morbidity and mortality, particularly during times of stress. This is thought to be due to an increased risk of cardiac arrhythmias, although the exact mechanisms involved have yet to be fully elucidated. The aim of the present study was to investigate the endocrine, cardiac autonomic and psychological responses of diabetic patients with and without autonomic neuropathy to a single breath of 35% CO(2).

METHODS

The 35% CO(2) challenge was performed in 20 male diabetic subjects, 11 of whom had autonomic neuropathy.

RESULTS

Baseline and stimulated cortisol, prolactin, systolic blood pressure and emotional arousal were similar in the two groups. However, subjects with autonomic neuropathy failed to demonstrate the expected CO(2)-induced bradycardia seen in the non-neuropathic patients (p<0.0001).

CONCLUSIONS/INTERPRETATION

The CO(2) challenge can be safely and easily administered to produce hypothalamic-pituitary-adrenal axis and cardiac autonomic activation, as well as emotional arousal. The test clearly distinguishes between subjects with and without cardiac autonomic neuropathy and could be an important adjunct to the methods currently available for the investigation and diagnosis of diabetic autonomic neuropathy.

The Darwinian concept of stress: benefits of allostasis and costs of allostatic load and the trade-offs in health and disease

Why do we get the stress-related diseases we do? Why do some people have flare ups of autoimmune disease, whereas others suffer from melancholic depression during a stressful period in their life? In the present review possible explanations will be given by using different levels of analysis. First, we explain in evolutionary terms why different organisms adopt different behavioral strategies to cope with stress. It has become clear that natural selection maintains a balance of different traits preserving genes for high aggression (Hawks) and low aggression (Doves) within a population. The existence of these personality types (Hawks-Doves) is widespread in the animal kingdom, not only between males and females but also within the same gender across species. Second, proximate (causal) explanations are given for the different stress responses and how they work. Hawks and Doves differ in underlying physiology and these differences are associated with their respective behavioral strategies; for example, bold Hawks preferentially adopt the fight-flight response when establishing a new territory or defending an existing territory, while cautious Doves show the freeze-hide response to adapt to threats in their environment. Thus, adaptive processes that actively maintain stability through change (allostasis) depend on the personality type and the associated stress responses. Third, we describe how the expression of the various stress responses can result in specific benefits to the organism. Fourth, we discuss how the benefits of allostasis and the costs of adaptation (allostatic load) lead to different trade-offs in health and disease, thereby reinforcing a Darwinian concept of stress. Collectively, this provides some explanation of why individuals may differ in their vulnerability to different stress-related diseases and how this relates to the range of personality types, especially aggressive Hawks and non-aggressive Doves in a population. A conceptual framework is presented showing that Hawks, due to inefficient management of mediators of allostasis, are more likely to be violent, to develop impulse control disorders, hypertension, cardiac arrhythmias, sudden death, atypical depression, chronic fatigue states and inflammation. In contrast, Doves, due to the greater release of mediators of allostasis (surplus), are more susceptible to anxiety disorders, metabolic syndromes, melancholic depression, psychotic states and infection.

Cardiovascular autonomic regulation in preterm infants: the effect of atropine

To study cardiovascular autonomic control, we assessed the effect of atropine on heart rate (HR) and blood pressure (BP) variability in 12 preterm infants (range 26-32 wk) before intubation for respiratory insufficiency. Spectral power analysis of R-R interval and systolic BP (SBP) series were estimated in a low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.4-1.5 Hz) band and evaluated for a 10-min period before and a 10-min period after atropine sulfate (0.01 mg/kg). Baroreceptor reflex (BR) functioning was estimated using transfer function analysis at LF (coherence, gain, and phase). Atropine resulted in a significant 12% increase in steady-state HR (p < 0.01) and unchanged SBP. For R-R interval series, the total spectral power decreased 6-fold (p < 0.01), which was predominantly due to a reduction in the LF band (16-fold; p < 0.01). In contrast, we observed a significant increase (25%; p < 0.05) in total spectral power of SBP series partly as a result of an increase in HF power. The LF power of SBP series was not altered. The median LF transfer gain (BR sensitivity) between SBP and R-R interval decreased from 4.2 to 1.4 ms/mm Hg (p < 0.01) after atropine. The LF phase relationship (BP leads R-R interval fluctuations by approximately 4 s) was not changed after atropine. In conclusion, even in preterm infants in distress, atropine modulates HR and BP variability, suggesting that BR-mediated parasympathetic control of heart rate is of significance for cardiovascular control at that age.

Circadian variation in cardiac autonomic activity: reactivity measurements to different types of stressors

The role of endogenous circadian rhythmicity in autonomic cardiac reactivity to different stressors was investigated. A constant routine protocol was used with repeated exposure to a dual task and a cold pressor test. The 29 subjects were randomly divided into two groups in order to manipulate prior wakefulness. Group 1 started at 09:00 h immediately after a monitored sleep period, whereas group 2 started 12 h later. Measures of interbeat intervals (IBI), respiratory sinus arrythmia (RSA, a measure of parasympathetic activity), pre-ejection period (PEP, a measure of sympathetic activity), as well as core body temperature (CBT) were recorded continuously. Multilevel regression analyses (across-subjects) revealed significant (mainly 24 h) sinusoidal circadian variation in the response to both stressors for IBI and RSA, but not for PEP. Individual 24 + 12 h cosine fits demonstrated a relatively large interindividual variation of the phases of the IBI and RSA rhythms, as compared to that of the CBT rhythm. Sinusoidal by group interactions were found for IBI and PEP, but not for RSA. These findings were interpreted as an indication for endogenous circadian and exogenous parasympathetic (vagal) modulation of cardiac reactivity, while sympathetic reactivity is relatively unaffected by the endogenous circadian drive and mainly influenced by exogenous factors.

"Scared stiff": catatonia as an evolutionary-based fear response

Catatonia, long viewed as a motor disorder, may be better understood as a fear response, akin to the animal defense strategy tonic immobility (after G. G. Gallup & J. D. Maser, 1977). This proposal, consistent with K. L. Kahlbaum's (1874/1973) original conception, is based on similarities between catatonia and tonic immobility ("death feint") as well as evidence that catatonia is associated with anxiety and agitated depression and responds dramatically to benzodiazepines. It is argued that catatonia originally derived from ancestral encounters with carnivores whose predatory instincts were triggered by movement but is now inappropriately expressed in very different modern threat situations. Found in a wide range of psychiatric and serious medical conditions, catatonia may represent a common "end state" response to feelings of imminent doom and can serve as a template to understand other psychiatric disorders.

Introducing a baroreflex model for studying cardiovascular effects of mental workload

A quantitative baroreflex control model is presented aimed at estimating differences in autonomic activation due to mental task performance. The model, which builds on earlier work of Wesseling and colleagues, is strongly supported by well-established knowledge of physiological control processes. Spectral measures of heart rate and blood pressure variability provide the information to estimate autonomic gain and tone parameters. The article gives a detailed model description as well as an evaluation in terms of spectral variability distributions, respiratory sinus arrhythmia, and vagal control mechanisms. The estimation procedure is outlined while presenting two studies that describe the effects of mental workload and vagal blockade, respectively. It is concluded that, using the model approach, cardiovascular effects of mental task performance can be interpreted in terms of specific changes in autonomic state. The model is implemented in a Matlab/Simulink environment and is available for other researchers in the field.

Regional cerebral blood flow correlates with heart period and high-frequency heart period variability during working-memory tasks: Implications for the cortical and subcortical regulation of cardiac autonomic activity

The aim of the present study was to characterize the functional relationships between behaviorally evoked regional brain activation and cardiac autonomic activity in humans. Concurrent estimates of regional cerebral blood flow (rCBF; obtained by positron emission tomography), heart period, and high-frequency heart period variability (HF-HPV; an indicator of cardiac parasympathetic activity) were examined in 93 adults (aged 50-70 years) who performed a series of increasingly difficult working-memory tasks. Increased task difficulty resulted in decreased heart period (indicating cardioacceleration) and decreased HF-HPV (indicating decreased cardiac parasympathetic activity). Task-induced decreases in heart period and HF-HPV were associated with concurrent increases and decreases in rCBF to cortical and subcortical brain regions that are speculated to regulate cardiac autonomic activity during behavioral processes: the medial-prefrontal, insular, and anterior cingulate cortices, the amygdala-hippocampal complex, and the cerebellum. These findings replicate and extend a small number of functional neuroimaging studies that suggest an important role for both cortical and subcortical brain systems in human cardiac autonomic regulation.

Psychophysiology of aggression, psychopathy, and conduct problems: a meta-analysis

A meta-analysis of 95 studies was conducted to investigate the relations of heart rate (HR) and electrodermal activity (EDA) with aggression, psychopathy, and conduct problems. Analyses revealed a complex constellation of interactive effects, with a failure in some cases of autonomic patterns to generalize across antisocial spectrum behavior constructs. Low resting EDA and low task EDA were associated with psychopathy/sociopathy and conduct problems. However, EDA reactivity was positively associated with aggression and negatively associated with psychopathy/sociopathy. Low resting HR and high HR reactivity were associated with aggression and conduct problems. Physiology--behavior relations varied with age and stimulus valence in several cases. Empirical and clinical implications are discussed.

Physiological regulation and infantile anorexia: a pilot study

OBJECTIVE

To examine whether infantile anorexia is associated with physiological dysregulation.

METHOD

This study included eight toddlers with infantile anorexia and eight healthy eaters matched for age, race, socioeconomic status, and gender. Physiological measures of heart period and respiratory sinus arrhythmia were assessed across three different situations: mother-toddler interaction, toddler-stranger interaction, and toddler left alone with a toy while mother and stranger talked to each other at the other side of the room.

RESULTS

Across all three situations, toddlers with infantile anorexia showed significantly shorter heart periods (i.e., faster heart rates) than controls (p <.05). In addition, as social demand decreased from episode 2 to episode 3, control toddlers exhibited an increase in respiratory sinus arrhythmia, whereas toddlers with infantile anorexia showed a decrease in respiratory sinus arrhythmia (p <.001).

CONCLUSIONS

Toddlers with infantile anorexia showed consistently shorter heart periods and were less adaptive in their physiological regulation than controls. Such physiological dysregulation may constitute a tendency for less optimal internal homeostatic regulation of feeding in toddlers with infantile anorexia.

Respiratory sinus arrhythmia as an index of emotional response in young adults

The relationship between respiratory sinus arrhythmia (RSA) and valence and arousal remains unclear. In the present study, the associations between emotion responses and tonic or task-related changes in RSA were assessed. Specifically, the sensitivities of changes in interbeat interval, RSA, and skin conductance to the valence and arousal values of emotional stimuli were examined. This study also explored the association between tonic RSA and subjective, expressive, and physiological emotional responses. Response measures were collected from 56 adults during baseline and film-viewing periods. Tonic RSA was not significantly related to any of the response measures. Increased skin conductance and decreased RSA were associated with arousal independent of valence. Interbeat interval was related to affective valence and not arousal. These findings suggest that RSA may be a useful adjunct to skin conductance measures in assessing emotional arousal.

Emotional effects of startling background music during reading news reports: The moderating influence of dispositional BIS and BAS sensitivities

We examined the moderating influence of dispositional behavioral inhibition system (BIS) and behavioral activation system (BAS) sensitivities on the relationship of startling background music with emotion-related subjective and physiological responses elicited during reading news reports, and with memory performance among 26 adult men and women. Physiological parameters measured were respiratory sinus arrhythmia (RSA), electrodermal activity (EDA), and facial electromyography (EMG). The results showed that, among high BAS individuals, news stories with startling background music were rated as more interesting and elicited higher zygomatic EMG activity and RSA than news stories with non-startling music. Among low BAS individuals, news stories with startling background music were rated as less pleasant and more arousing and prompted higher EDA. No BIS-related effects or effects on memory were found. Startling background music may have adverse (e.g., negative arousal) or beneficial effects (e.g., a positive emotional state and stronger positive engagement) depending on dispositional BAS sensitivity of an individual. Actual or potential applications of this research include the personalization of media presentations when using modern media and communications technologies.

Heart period and variability findings in preschool children with posttraumatic stress symptoms

BACKGROUND

Traumatic experiences for young children might result in profound neurodevelopmental changes, compared with adults. Our aim was to examine autonomic control of heart rate in traumatized young children.

METHODS

Sixty-two children who had suffered traumas and 62 nontraumatized control children, aged 20 months to 6 years, were assessed for posttraumatic stress disorder (PTSD) symptoms, interbeat interval, respiratory sinus arrhythmia (RSA), family rehearsal of the trauma, and parent-child relationship quality.

RESULTS

Traumatized children with PTSD and traumatized children without PTSD both had decreased heart period in response to a trauma stimulus relative to the nontraumatized group (both p < .0167). there was no main effect for RSA change scores, however, there was a significant interaction effect between parental positive discipline with PTSD symptoms and RSA. The most sympathetic children had decreased RSA during the trauma stimulus when they had caregivers with less positive discipline during a clean-up nd family rehearsal with PTSD symptoms.

CONCLUSIONS

These findings underscore that psychopathology in young children ought to be assessed in the context of psychophysiology and parent-child relationship to optimally understand the mechanisms of maladaptation during this complex developmental period.

Pacifier use modifies infant's cardiac autonomic controls during sleep

OBJECTIVE

The risk for sudden infant death (SIDS) was postulated to decrease with the use of a pacifier and by conditions increasing parasympathetic tonus during sleep. We evaluated the influence of a pacifier on cardiac autonomic controls in healthy infants.

STUDY DESIGN

Thirty-four healthy infants were studied polygraphically during one night: 17 infants regularly used a pacifier during sleep and 17 never used a pacifier. Thumb users or occasional pacifier users were not included in the study. The infants were recorded at a median age of 10 weeks (range 6-18 weeks). Autonomic nervous system (ANS) was evaluated by spectral analysis of the heart rate (HR). The high frequency component of HR spectral analysis reflected parasympathetic tonus and the low frequency on high frequency ratio corresponded to the sympathovagal balance.

RESULTS

Most infants (63.6%) lost their pacifier within 30 min of falling asleep. Sucking periods were associated with increases in cardiac sympathovagal balance. During non-sucking periods, in both REM and NREM sleep, infants using a pacifier were characterized by lower sympathetic activity and higher parasympathetic tonus compared with non-pacifier users.

CONCLUSIONS

The use of pacifiers modifies cardiac autonomic controls during both sucking and non-sucking sleep periods. Non-nutritive sucking could regulate autonomic control in infants. These findings could be relevant to mechanisms implicated in the occurrence of sudden infant deaths during sleep.

Secretin: hypothalamic distribution and hypothesized neuroregulatory role in autism

1. This study aims (1) to determine whether secretin is synthesized centrally, specifically by the HPA axis and (2) to discuss, on the basis of the findings in this and previous studies, secretin's possible neuroregulatory role in autism. 2. An immunocytochemical technique with single-cell resolution was performed in 12 age/weight-matched male rats pretreated with stereotaxic microinjection of colchicine (0.6 microg/kg) or vehicle into the lateral ventricle. Following 2-day survival, rats were anesthetized and perfused for immunocytochemistry. Brain segments were blocked and alternate frozen 30-microm sections incubated in rabbit antibodies against secretin, vasoactive intestinal peptide, glucagon, or pituitary-adenylate-cyclase-activating peptide. Adjacent sections were processed for Nissl stain. Preadsorption studies were performed with members of the secretin peptide family to demonstrate primary antibody specificity. 3. Specificity of secretin immunoreactivity (ir) was verified by clear-cut preadsorption control data and relatively high concentrations and distinct topographic localization of secretin ir to paraventricular/supraoptic and intercalated hypothalamic nuclei. Secretin levels were upregulated by colchicine, an exemplar of homeostatic stressors, as compared with low constitutive expression in untreated rats. 4. This study provides the first direct immunocytochemical demonstration of secretinergic immunoreactivity in the forebrain and offers evidence that the hypothalamus, like the gut, is capable of synthesizing secretin. Secretin's dual expression by gut and brain secretin cells, as well as its overlapping central distribution with other stress-adaptation neurohormones, especially oxytocin, indicates that it is stress-sensitive. A neuroregulatory relationship between the peripheral and central stress response systems is suggested, as is a dual role for secretin in conditioning both of those stress-adaptation systems. Colchicine-induced upregulation of secretin indicates that secretin may be synthesized on demand in response to stress, a possible mechanism of action that may underlie secretin's role in autism.

Particulate matter exposure in cars is associated with cardiovascular effects in healthy young men

Exposure to fine airborne particulate matter (PM(2.5)) is associated with cardiovascular events and mortality in older and cardiac patients. Potential physiologic effects of in-vehicle, roadside, and ambient PM(2.5) were investigated in young, healthy, nonsmoking, male North Carolina Highway Patrol troopers. Nine troopers (age 23 to 30) were monitored on 4 successive days while working a 3 P.M. to midnight shift. Each patrol car was equipped with air-quality monitors. Blood was drawn 14 hours after each shift, and ambulatory monitors recorded the electrocardiogram throughout the shift and until the next morning. Data were analyzed using mixed models. In-vehicle PM(2.5) (average of 24 microg/m(3)) was associated with decreased lymphocytes (-11% per 10 microg/m(3)) and increased red blood cell indices (1% mean corpuscular volume), neutrophils (6%), C-reactive protein (32%), von Willebrand factor (12%), next-morning heart beat cycle length (6%), next-morning heart rate variability parameters, and ectopic beats throughout the recording (20%). Controlling for potential confounders had little impact on the effect estimates. The associations of these health endpoints with ambient and roadside PM(2.5) were smaller and less significant. The observations in these healthy young men suggest that in-vehicle exposure to PM(2.5) may cause pathophysiologic changes that involve inflammation, coagulation, and cardiac rhythm.

Longitudinal relations between child vagal tone and parenting behavior: 2 to 4 years

The longitudinal relations between physiological markers of child emotion regulation and maternal parenting practices were examined from 2 to 4 years of age. At Time 1, cardiac vagal tone was assessed for one hundred four 2-year-olds (54 females); their mothers completed an assessment of parenting styles. Two years later, at Time 2, 84 of the original participants were reassessed on measures of cardiac vagal tone and parenting style. Results indicated both baseline cardiac vagal tone and maternal parenting practices to be stable from 2 to 4 years of age. Children's cardiac vagal tone predicted specific parenting practices from the toddler to preschool years. Further, child cardiac vagal tone moderated maternal restrictive-parenting practices from 2 to 4 years of age; mothers of children who were highly or moderately physiologically dysregulated were more likely to report restrictive parenting practices at both 2 and 4 years of age.

The paradox of "detachment disorders": binding-disruptions of dissociative process

This case is discussed in the contexts of affect theory, attachment theory, and dissociative experience. Dissociative adaptations to living that become entrenched resistances during psychotherapeutic inquiry give way to a scrupulous attention to the characteristics of dissociative experiencing. Somatosensory free association and appreciation of experiential aspects of depersonalization, derealization, and dissociative amnesia open new areas of negotiation between patient and therapist. Paradigms from infant attachment and adult attachment research parsimoniously explicate psychodynamic formulations. "Conflicted interest" and "conflicted disinterest" are proposed to flesh out appreciation of the child's inner experience during Type A and Type C attachment experiences. The Type D attachment style is consistent with a dissociative phenotype. The concept of "isolated subjectivity" can help explain the extent to which individuals both know and don't know about their experience, in the same moment, and without conscious conflict or anxiety.

Children's narratives and patterns of cardiac reactivity

The present study examines the associations between narrative processing, narrative production, and cardiac rate and variability in children. Heart period (HP) and vagal tone (VT) were computed for fifty-eight 7-year-olds (29 males) during a resting baseline and during epochs in which the children listened to and completed a selected set of story-stems from the MacArthur Story-Stem Battery (I. Bretherton, D. Oppenheim, H. Buchsbaum, R. N. Emde, & the MacArthur Narrative Group, 1990). Significant decreases in HP and VT were observed between a resting baseline and epochs of story-stem presentation by the experimenter. In addition, HP was shorter and VT lower during children's narrative production to emotionally laden story-stems compared with narration to a neutral story-stem. Furthermore, narrative and cardiac responses to stories containing separation-reunion themes reflected increased emotional and cognitive load compared with responses to stories that did not contain such themes. Finally, children who showed VT suppression in response to emotion-laden stories produced more coherent and adaptive narratives compared to those of children who did not show VT suppression. The findings suggest interplay between the cognitive-emotional processes associated with narrative processing and production and cardiac activation patterns.

Physiological and Emotional Reactivity to Learning and Frustration

This study examined the behavioral (arm, facial) autonomic (heart rate, respiratory sinus arrhythmia [RSA], and adrenocortical axis) reactivity of 56 4-month-old infants in response to contingency learning and extinction-induced frustration. During learning, infants displayed increases in operant arm response and positive emotional expressions. Changes in average RSA(V(NA)) paralleled the observed changes in facial expressions in general and maintained an inverse relation with heart rate throughout most of the session. When frustrated by extinction, infants displayed increases in negative expressions, heart rate, and a brief increase in RSA(V(NA)) followed by a significant decrease. No significant changes were observed for cortisol. These behavioral and facial responses are consistent with earlier work. The physiological changes, along with the facial expressions and instrumental responses, indicate that the autonomic nervous system functions as a coordinated affect system by 4 months of age.

Stuttering, emotions, and heart rate during anticipatory anxiety: a critical review

Persons who stutter often report their stuttering is influenced by emotional reactions, yet the nature of such relation is still unclear. Psychophysiological studies of stuttering have failed to find any major association between stuttering and the activity of the sympathetic nervous system. A review of published studies of heart rate in relation to stressful speech situations indicate that adults who stutter tend to show a paradoxical reduction of heart rate compared with nonstuttering persons. Reduction of heart rate has also been observed in humans and mammals during anticipation of an unpleasant stimulus, and is proposed to be an indication of anticipatory anxiety resulting in a "freezing response" with parasympathetic inhibition of the heart rate. It is suggested that speech-related anticipatory anxiety in persons who stutter is likely to be a secondary, conditioned reaction based on previous experiences of stuttering.

EDUCATIONAL OBJECTIVES

The reader will be able to: (1) describe how the autonomic nervous system is modulated by emotional responses; (2) explain how anticipatory fear often results in inhibition of heart rate due to parasympathetic activation; (3) discuss why emotional reactions in persons who stutter may be secondary to negative experiences of speech problems.

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.

Social Engagement and Attachment

This article focuses on the importance of social engagement and the behavioral and neurophysiological mechanisms that allow individuals to reduce psychological and physical distance. A model of social engagement derived from the Polyvagal Theory is presented. The model emphasizes phylogeny as an organizing principle and includes the following points: (1) there are well-defined neural circuits to support social engagement behaviors and the defensive strategies of fight, flight, and freeze; (2) these neural circuits form a phylogenetically organized hierarchy; (3) without being dependent on conscious awareness, the nervous system evaluates risk in the environment and regulates the expression of adaptive behavior to match the neuroception of a safe, dangerous, or life-threatening environment; (4) social engagement behaviors and the benefits of the physiological states associated with social support require a neuroception of safety; (5) social behaviors associated with nursing, reproduction, and the formation of strong pair bonds require immobilization without fear; and (6) immobilization without fear is mediated by a co-opting of the neural circuit regulating defensive freezing behaviors through the involvement of oxytocin, a neuropeptide in mammals involved in the formation of social bonds. The model provides a phylogenetic interpretation of the neural mechanisms mediating the behavioral and physiological features associated with stress and several psychiatric disorders.

Autonomic responses to sighs in healthy infants and in victims of sudden infant death

OBJECTIVE

Sigh, defined as an isolated breath with an increased tidal volume, can be associated with abrupt changes in heart rate (HR) or blood oxygenation. Sigh may be followed by a central apnea. As impairment of autonomic control was postulated in future SIDS victims, we hypothesized that their autonomic responses to sighs were different from those of healthy control infants.

METHODS

Sighs followed by central apnea were studied in the sleep recordings of 18 infants who eventually died of SIDS and of 18 control infants. The infants of the two groups were matched for sex, gestational age, postnatal age, weight at birth and sleep position during sleep recording. HR autoregressive power spectral analysis was performed on RR intervals preceding and following sighs.

RESULTS

In all infants, most sighs followed by an apnea were found in NREM sleep. Compared to the control infants, the future SIDS victims were characterized by a greater sympathovagal balance and a lower parasympathetic tonus before the sighs. Following the sighs, no more differences were found in NREM sleep.

CONCLUSION

Based on the present findings, it can be postulated that sighs contribute to reset autonomic tonus during NREM sleep.

Familiality of heart rate and cardiac-related autonomic activity in five-month-old twins: The Québec newborn twins study

The familiality of infant sleeping heart rate (HR) and cardiac-related autonomic activity, as indexed by spectral analysis of HR variability (HRV) and response to postural change, was investigated in 322 5-month-old twin pairs. The postural change elicited only minor changes in cardiovascular activity. As a result, analyses focused on supine cardiovascular activity. Multivariate genetic modeling indicated that individual differences in sleeping HR and high frequency (HF) HRV were determined by unique environmental and distinct additive genetic factors. These variables, along with low frequency (LF) HRV, were also affected by overlapping familial environmental influences. Familial influences in HF HRV were more pronounced for baby girls than boys. Estimates of relative LF and HF HRV were determined by common (familial) and unique environmental factors; familial influences on these estimates did not overlap with familial influences on sleeping HR.

Short-term stability of physiological measures in kindergarten children: Respiratory sinus arrhythmia, heart period, and cortisol

The short-term stability of measures of respiratory sinus arrhythmia (RSA), heart period, and salivary cortisol and the relation of these variables to one another and to measures of social competence in kindergartners were examined. Physiological measures were collected during multiple individual sessions with 30 kindergarten children, ages 5 to 6 years. Three sessions were scheduled at 2-week intervals and included a negative affect task as a challenge. Cardiovascular and cortisol responses to the challenge were assessed. Results indicated that baseline measures of RSA and heart period were stable across time. Baseline cortisol levels were not stable. The change in RSA in response to a task that elicited emotional responses was not stable over time. Consistent with findings observed in adults and older children, changes in RSA were related to the cortisol response. Children who increased cortisol over the course of Session 1 exhibited larger decreases in RSA than children who did not show increased cortisol levels. In addition, the children who had larger decreases in RSA had higher ratings of sociability on the Colorado Childhood Temperament Inventory. Greater decreases in heart period during the task were associated with lower ratings of shyness. The relation of RSA measures to ratings of social competence supports the Polyvagal Theory (Porges, 1995, 2001), which suggests that the ability to engage and disengage with objects and people in one's environment, necessary for social competence, is related to the regulation of vagal control of the heart.

Infant attachment and temperament as predictors of subsequent externalizing problems and cardiac physiology

BACKGROUND

The primary objective of this study was to examine the extent to which both individual child temperament and parent-child relationship quality independently and/or interactively predicted physiological, psychosocial, and behavioral 'outcomes'. Employing a longitudinal prospective design over three years, statistical associations were found among infant attachment, uninhibited temperament, and 4-year behavioral and physiological functioning that supported a bio-psychosocial model of development.

METHOD

Three cohorts totaling 140 children and their mothers visited the laboratory for observational assessments of attachment classification at age 14 months (Strange Situation), behavioral inhibition at 24 months, and social behaviors with unfamiliar peers at age 4 years. Cardiac measures of heart rate and respiratory sinus arrhythmia (RSA) were collected at every time point. At age 4 years maternal ratings of child temperament and behaviors were also obtained.

RESULTS

Analyses of variance (ANOVAs) with inhibition group (high, moderate, low) and attachment classification (A, B, C) revealed that the low inhibited group had significantly higher activity level scores and displayed significantly less reticence at 4 years compared to the moderately and highly inhibited groups. Infants who had an avoidant attachment with their mothers had more externalizing problems (aggressive behaviors) at age 4 than either securely or ambivalently attached infants. This predictive relation, however, was qualified by an interaction whereby avoidant attachment and uninhibited temperament together predicted a higher incidence of externalizing behavior problems. Moreover, infants' avoidant attachment was not concurrently but predictively associated with lower heart rate and high RSA at age 4 years. Therefore, an avoidant mother-child relationship in infancy could influence the development of an underaroused autonomic profile in early childhood.

CONCLUSIONS

Consistent with bio-psychosocial models of development, these findings support the contention that both early child temperament and parent-child relationship quality contribute to subsequent psychological/behavioral and physiological functioning.

The Effects of Intensive Voice Treatment on Facial Expressiveness in Parkinson Disease

OBJECTIVE

The purpose of the present retrospective study was to examine the effects of intensive voice therapy on facial expression in Parkinson disease.

BACKGROUND

Parkinson disease (PD) often presents with symptoms that reduce communicative effectiveness on multiple levels, including decreased vocal loudness and reduced facial mobility. Recent advances in voice treatment have provided the first short- and long-term efficacy data indicating improvements in voice and speech following intensive voice therapy (Lee Silverman Voice Treatment [LSVT]). Anecdotal reports from both clinicians and patients indicate that the LSVT also has a positive impact on facial expression. These observations suggest a need to investigate more directly the effects of voice therapy on facial movement and expressiveness in PD.

METHOD

Forty-four individuals with idiopathic PD participated in this study. Video data were taken from recordings of individuals with PD who had received either one month of phonation-based treatment (LSVT) or respiratory treatment (RT) as part of a large treatment efficacy study designed to examine the effects of different types of therapy on speech and voice in PD. Twenty-second video samples of all subjects taken before and after treatment were paired and played at random without sound to trained raters, who judged each pair of video clips for facial mobility and engagement. All recordings were made while subjects were engaged in conversational speech.

RESULTS

Inter-rater reliability was extremely high (0.90) for both the rating of facial mobility and engagement. Overall, members of the LSVT group received more ratings of increased facial mobility (P = 0.036) and engagement (P = 0.056) following treatment relative to members of the RT group. In addition, the extent of change for facial mobility after treatment was perceived as greater (P = 0.05) for the LSVT group than for the RT group.

CONCLUSIONS

These results indicate that intensive voice therapy may have a positive effect on facial expressivity in PD. Such findings lend support to contemporary theories relating multiple expressive modalities (e.g., voice, face, and gesture) and suggest that targeting voice may be an effective and efficient way to influence expressive output in general.

Reductions in phenomenological, physiological and attentional indices of depressive mood after 2 Hz rTMS over the right parietal cortex in healthy human subjects

Research into emotion and emotional disorders by repetitive transcranial magnetic stimulation (rTMS) has largely been restricted to the prefrontal regions. There is, however, also evidence for the parietal cortex being implicated in emotional (dys-)functioning. Here we used rTMS to investigate a role of the right parietal cortex in depression. In a placebo-controlled design, 2 Hz rTMS at 90% of the individual motor threshold (MT) was applied over the right parietal cortex of eight healthy subjects for 20 min continuously. Effects on mood, autonomic activity and motivated attention were investigated. Significant reductions in depressive mood were observed immediately following and 30 min after stimulation. Moreover, these findings were objectified by a concurring pattern of autonomically mediated changes in the attentional processing of angry facial expressions. These data suggest a role for the right parietal cortex in affective brain circuits regulating phenomenological, physiological and attentional aspects of depressive functioning.

Physiological and neurocognitive correlates of adaptive behavior in preschool among children in Head Start

This study examined physiological and neurocognitive correlates of teacherreported adaptive behavior in preschool among children in Head Start. Child physiology was assessed by cardiac vagal tone and was measured during a baseline period and during the administration of a mildly effortful cognitive task. Neurocognitive function was measured using two tasks of executive function, which require children to inhibit a prepotent response, while remembering and executing the rule for correct responding. Parents reported on aspects of child negative emotionality associated with fear and anger. Information on child receptive language ability was also collected. Although correlates of teacher-reported social competence and on-task behavior were expected to be similar, some evidence for differentiation was obtained. Results indicated that higher resting vagal tone, vagal increase during the administration of the cognitive task, and higher levels of fearful emotionality were related to higher ratings of social competence, after adjusting for levels of on-task behavior. In contrast, lower resting vagal tone, vagal suppression in response to the cognitive task, and higher levels of executive function were associated with higher teacher ratings of on-task behavior, adjusted for social competence. Implications are considered of findings for developmental relations between social and academic competence and adaptation to preschool among children in Head Start.

The Polyvagal Theory: phylogenetic contributions to social behavior

The scientific legacy of Paul MacLean provides important insights into the neural substrate of adaptive social behavior in mammals. Through his research and visionary conceptualizations, current investigators can legitimately study social behavior from a neurobiological perspective. His research and writings provided three important contributions. First, he emphasized the importance of evolution as an organizing principle that shaped both the structure of the nervous system and the adaptive social behavior. Second, by defining the limbic system, he legitimized the biological perspective in the study of emotion. Third, he recognized the important role of the vagal afferents in the regulation of higher brain structures. The paper will focus on the Polyvagal Theory. The Polyvagal Theory is a new conceptualization of the role of vagus and employs several features that MacLean emphasized including the importance of evolution, limbic structures and vagal afferents. The Polyvagal Theory builds on these early findings by MacLean and focuses on the link between phylogenetic changes in the autonomic nervous system and social behavior. By focusing on the phylogenetic changes in the structure of the vagus and the role that the vagus plays in the neural regulation of visceral state, new insights regarding social behavior emerge. Moreover, by articulating the phylogenetically organized hierarchy of neural circuits, insights into benefits of social behavior become evident as do an understanding of the behavioral and physiological features associated with stress and psychiatric disorders.

Beyond the treatment of epilepsy: new applications of vagus nerve stimulation in psychiatry

Vagus nerve stimulation (VNS) in humans generally refers to stimulation of the left vagus nerve at the cervical level VNS is an established treatment largely devoid of severe side effect for medically refractory partial onset seizures and has been used in more than 16,000 patients. Over the past 5 years, applications in other neuropsychiatric disorders have been investigated with a special emphasis on depression. Recent data from an open-label, multi-center pilot study involving 60 patients suggest a potential clinical usefulness in the acute and maintenance treatment of drug-resistant depressive disorder. The perspective of VNS as along-term treatment with the advantage of assured compliance makes it an interesting technique to potentially treat drug-resistant depression. However, definite therapeutic effects of clinical significance remain to be confirmed in large placebo-controlled trial. Results of clinical pilot studies involving patients suffering from obesity and Alzheimer's disease indicate that VNS might induce weight loss and improve cognition. Besides its clinical usefulness, VNS can be used as a research tool, allowing neurophysiologic investigations of the parasympathetic system and its interactions with other parts of the central nervous system.

Heart rate and respiration in reptiles: contrasts between a sit-and-wait predator and an intensive forager

The current study investigated respiration and heart rate in two species of reptiles with distinct behavioral strategies: (1) the Sudan plated lizard (Gerrhosaurus major), a sit-and-wait predator; and (2) the Savanna monitor (Varanus exanthematicus), an intensive forager. It was hypothesized that (a) the plated lizard would not express respiratory sinus arrhythmia, and (b) the monitor, a reptile with behavioral and physiological characteristics similar to mammals, might express respiratory sinus arrhythmia, a pattern previously observed only in mammals. The data demonstrated that although there were strong vagal influences on the heart, respiratory activity was not manifested in the heart rate pattern of the plated lizards. In contrast, the monitor exhibited a reliable ventilatory influence on the heart rate pattern, although the pattern differed from the respiratory sinus arrhythmia observed in mammals. Consistent with the Polyvagal Theory (), the vagal control of the reptilian heart in both species appears to be mediated through the phylogenetically older unmyelinated system, a system that evolved to support metabolic conservation and not social behavior.

The neurobiology of childhood trauma and abuse

During the past decade there has been rapid progress in the understanding of the effects of exposure to traumatic life experiences on subsequent psychopathology in children. Trauma exposure affects what children anticipate and focus on and how they organize the way they appraise and process information. Trauma-induced alterations in threat perception are expressed in how they think, feel, behave, and regulate their biologic systems. The task of therapy is to help these children develop a sense of physical mastery and awareness of who they are and what has happened to them to learn to observe what is happening in present time and physically respond to current demands instead of recreating the traumatic past behaviorally, emotionally, and biologically.

Cortisol, prolactin, growth hormone and neurovegetative responses to emotions elicited during an hypnoidal state

The present study describes the responses of cortisol, prolactin and growth hormone (GH) to emotions elicited during sessions in which an hypnoidal state was induced. The purpose of the study was to provide answers for the following questions: 1) Do sessions with an emotional content have more hormonal surges than baseline, relaxation-only, sessions? 2) Does the induction of a fantasy of pregnancy and nursing elicit a prolactin response? 3) Are there any associations between surges of different hormones? 4) Are hormonal responses related to the intensity, type, or mode of expression of the emotions? For this purpose, thirteen volunteers and twelve patients with minor emotional difficulties were studied during sessions under hypnosis. The period of observation lasted for about three hours. Heart rate (HR), skin conductance (SC) and vagal tone (VT) were monitored. Serum cortisol, prolactin and growth hormone were sampled every 15 minutes. The volunteers had three types of sessions- "blank", consisting of relaxation only (12 sessions), "breast feeding", in which a fantasy of pregnancy and breast feeding was induced (12 sessions) and "free associations" in which the subjects were encouraged to evoke experiences or feelings (17 sessions). The patients had only sessions of free associations (38 sessions). Sessions of free associations had more hormonal surges than "blank" and "breast feeding" sessions. This was true for cortisol (8/17 v.3/24; p < 0.03), prolactin (7/17 v. 3/24; p < 0.05) and GH (9/17 v. 4/24; p < 0.02). During the 55 sessions of free associations (volunteers plus patients) there were 32 surges of cortisol, 18 of prolactin and 28 of GH. Cortisol and prolactin surges were negatively correlated (p < 0.03). GH had no significant association with either cortisol or prolactin. Visible emotions were positively associated with GH surges (p < 0.05). but not with cortisol or prolactin. Cortisol surges were correlated positively with evocations of real events (p < 0.01) and negatively with evocations containing defensive elements (p < 0.01). Cortisol correlated positively with shock and intimidation (p < 0.02) and negatively with rage (p < 0.04). The AUC of the cortisol peaks during shock and intimidation was significantly higher than that of the pool of all other cortisol peaks (12.4 micromol x min x l(-1) v. 7.1 micromol x min x l(-1); p < 0.005). Rage had a marginally significant positive association with prolactin surges (p=0.07). The distribution of GH surges did not show any significant association with types of emotions. The present study provides evidence that cortisol, prolactin and GH respond to psychological stress in humans. However, they are regulated differently from one another. Cortisol and prolactin surges appear to be alternative forms of response to specific emotions. GH surges depend on the intensity of the emotion, probably as a consequence of the associated muscular activity. The current paradigm of stress, implying corticotrophin-releasing hormone (CRH) as the initial step of a cascade of events, is insufficient to account for the diversity of hormonal changes observed in psychological stress in humans.