Cardiac Arousal Research Articles

Trajectories of Maternal Behavior, Infant's Respiratory Sinus Arrhythmia, and Emotional Recovery Following the Still Face Paradigm.

The development of emotion regulation is integral to children's socioemotional adjustment. Respiratory sinus arrhythmia (RSA) reflects parasympathetic regulation of cardiac arousal and is thought to be an indicator of emotion regulation. However, it is unclear how RSA is associated with positive maternal behaviors and infant emotional recovery in real time over the course of a recovery period following a social stressor. Mothers and their 5- to 6-month-old infants (N=143) completed the Still Face paradigm. Using a series of autoregressive latent trajectory models, the current study aimed to elucidate the associations among observed maternal warmth, infant RSA, and observed infant negative affect across a 5-min observation. The hypotheses were that trajectories of maternal warmth would predict trajectories of infant RSA and negative affect, and that trajectories of RSA would be associated with the infants' observed negative affect. Change in maternal warmth was associated with infant negative affect and RSA at the end of the reunion and change in RSA was associated with ultimate levels of negative affect. The results provide partial support for our hypothesis that maternal warmth supports infant physiological, and in turn, emotional recovery.

Fear of physical activity relates to cardiac interoception and symptom distress in patients with chronic heart failure

BackgroundPatients with chronic heart failure often experience symptoms during physical activity, such as shortness of breath and tachycardia, which may result in fear of physical activity (FoPA). This study tested whether interoception (i.e., the perception of body sensations) and symptom distress (i.e., negative appraisal of symptoms) are associated with FoPA in outpatients with chronic heart failure. MethodFoPA was assessed with the Fear of Activities in Situations (FActS) in patients with diagnosed heart failure and healthy controls. A heartbeat tracking task and self-reports were used to assess interoceptive accuracy and interoceptive attention in patients and controls. Heart failure-related distress was assessed using ratings of symptom and treatment burden in patients. Multiple regression models were calculated to determine associations with continuous FoPA scores. ResultsPatients with low FoPA perceived their heartbeats more accurately than patients with high FoPA and healthy controls. Interoceptive accuracy and symptom distress explained almost half of the variance in FoPA, after adjustments for sex and disease severity, in patients with heart failure. ConclusionsIn patients inaccurate interoception and symptom distress were associated with high FoPA, independent of heart failure severity. The perception and appraisal of cardiac arousal and symptoms during physical activity deserve further attention to develop interventions to reduce FoPA in patients with heart failure. ClinicalTrials.gov IdentifierNCT03119298.

Dynamic regulatory processes among child welfare parents: Temporal associations between physiology and parenting behavior.

This study examined how temporal associations between parents' physiological and behavioral responses may reflect underlying regulatory difficulties in at-risk parenting. Time-series data of cardiac indices (second-by-second estimates of inter-beat intervals - IBI, and respiratory sinus arrhythmia - RSA) and parenting behaviors were obtained from 204 child welfare-involved parents (88% mothers, Mage = 32.32 years) during child-led play with their 3- to 7-year-old children (45.1% female; Mage = 4.76 years). Known risk factors for maltreatment, including parents' negative social cognitions, mental health symptoms, and inhibitory control problems, were examined as moderators of intra-individual physiology-behavior associations. Results of ordinary differential equations suggested increases in parents' cardiac arousal at moments when they showed positive parenting behaviors. In turn, higher arousal was associated with momentary decreases in both positive and negative parenting behaviors. Individual differences in these dynamic processes were identified in association with parental risk factors. In contrast, no sample-wide RSA-behavior associations were evident, but a pattern of increased positive parenting at moments of parasympathetic withdrawal emerged among parents showing more total positive parenting behaviors. This study illustrated an innovative and ecologically-valid approach to examining regulatory patterns that may shape parenting in real-time and identified mechanisms that should be addressed in interventions.

An RDoC-based approach to adolescent self-injurious thoughts and behaviors: The interactive role of social affiliation and cardiac arousal.

Recent theoretical models have posited that increases in self-injurious thoughts and behaviors (SITBs) during adolescence may be linked to failures in biological stress regulation in contexts of social stress. However, there is a lack of data examining this hypothesis during the transition to adolescence, a sensitive period of development characterized by changes across socioaffective and psychophysiological domains. Building on principles from developmental psychopathology and the RDoC framework, the present study used a longitudinal design in a sample of 147 adolescents to test whether interactions among experiences of social (i.e., parent and peer) conflict and cardiac arousal (i.e., resting heart rate) predicted adolescents' engagement in SITBs (i.e., nonsuicidal self-injury, NSSI; and suicidal ideation; SI) across 1-year follow-up. Prospective analyses revealed that adolescents experiencing a combination of greater peer, but not family, conflict and higher cardiac arousal at baseline showed significant longitudinal increases in NSSI. In contrast, social conflict did not interact with cardiac arousal to predict future SI. Findings indicate that greater peer-related interpersonal stress in adolescents may increase risk for future NSSI among youth with physiological vulnerabilities (i.e., higher resting heart rate) that may be markers of maladaptive stress responses. Future research should examine these processes at finer timescales to elucidate whether these factors are proximal predictors of within-day SITBs.

Multisensory integration of anticipated cardiac signals with visual targets affects their detection among multiple visual stimuli

Many studies have elucidated the multisensory processing of different exteroceptive signals (e.g., auditory-visual stimuli), but less is known about the multisensory integration of interoceptive signals with exteroceptive information. Here, we investigated the perceptual outcomes and electrophysiological brain mechanisms of cardio-visual integration by using participants’ electrocardiogram signals to control the color change of a visual target in dynamically changing displays. Reaction times increased when the target change coincided with strong cardiac signals concerning the state of cardiovascular arousal (i.e., presented at the end of ventricular systole), compared to when the target change occurred at a time when cardiac arousal was relatively low (i.e., presented at the end of ventricular diastole). Moreover, the concurrence of the target change and cardiac arousal signals modulated the event-related potentials and the beta power in an early period (~100 ms after stimulus onset), and decreased the N2pc and the beta lateralization in a later period (~200 ms after stimulus onset). Our results suggest that the multisensory integration of anticipated cardiac signals with a visual target negatively affects its detection among multiple visual stimuli, potentially by suppressing sensory processing and reducing attention toward the visual target. This finding highlights the role of cardiac information in visual processing and furthers our understanding of the brain dynamics underlying multisensory perception involving both interoception and exteroception.

Father-child physiological concordance on two timescales is differentially associated with paternal characteristics.

Conceptual work on interpersonal physiology suggests that the dynamic concordance between two person's physiological arousal may transpire on multiple timescales, and the timescale on which it unfolds may determine its psychological significance. The current study tested this hypothesis in the context of parent-child interaction by examining whether the concordance in their cardiac arousal on two timescales was differentially associated with parental characteristics. Using data from 98 fathers and their 3- to 5-year-old children during a task designed to frustrate young children, results indicated that the associations between cardiac concordance and fathers' self-reported parenting hassles emerged for the slower timescale (concordant increasing trends in arousal), whereas concordance on the faster timescale (concordant second-by-second reactivity) was associated with fathers' emotional clarity. Findings suggest that there may be multiple layers of concordant patterns in the dynamic associations between fathers' and children's cardiac arousal, which unfold on different timescales and bear different psychological significance.

Interoceptive training to target anxiety in autistic adults (ADIE): A single-center, superiority randomized controlled trial.

BackgroundThis trial tested if a novel therapy, Aligning Dimensions of Interoceptive Experience (ADIE), reduces anxiety in autistic adults. ADIE targets the association of anxiety with mismatch between subjective and behavioral measures of an individual's interoceptive sensitivity to bodily signals, including heartbeats.MethodsIn this superiority randomized controlled trial, autistic adults (18–65 years) from clinical and community settings in Southern England were randomly assigned (1:1) to receive six sessions of ADIE or an active ‘exteroceptive’ control therapy (emotional prosody identification). Researchers conducting outcome assessments were blind to allocation. ADIE combines two modified heartbeat detection tasks with performance feedback and physical activity manipulation that transiently increases cardiac arousal. Participants were followed-up one-week (T1) and 3-months post-intervention (T2). The primary outcome was Spielberger Trait Anxiety Score (STAI-T) at T2. Outcomes were assessed on an intention-to-treat basis using multiple imputation for dealing with missing values. This trial was registered at International Standard Randomized Controlled Trial Registry, ISRCTN14848787.FindingsBetween July 01, 2017, and December 31, 2019, 121 participants were randomly allocated to ADIE (n = 61) or prosody (n = 60) intervention groups. Data at T1 was provided by 85 (70%) participants (46 [75%] ADIE; 39 [65%] prosody). Data at T2 was provided by 61 (50%) participants (36 [59%] ADIE; 25 [42%] prosody). One adverse event (cardiac anxiety following ADIE) was recorded. A statistically significant group effect of ADIE on trait anxiety continued at T2 (estimated mean difference 3•23 [95% CI 1•13 to 5•29]; d = 0•30 [95% CI 0•09 to 0•51]; p = 0•005) with 31% of ADIE group participants meeting trial criteria for recovery (compared to 16% in the control group).InterpretationADIE can reduce anxiety in autistic adults, putatively improving regulatory control over internal stimuli. With little reliance on language and emotional insight, ADIE may constitute an inclusive intervention.Funding: MQTransforming Mental Health PsyImpact Grant.

Interoceptive cardiac signals selectively enhance fear memories.

Fear is coupled to states of physiological arousal. We tested how learning and memory of threat, specifically conditioned fear, is influenced by interoceptive signals. Forty healthy individuals were exposed to two threat (conditioned stimuli [CS+], paired with electrocutaneous shocks) and two safety (CS-) stimuli, time-locked to either cardiac ventricular systole (when arterial baroreceptors signal cardiovascular arousal to brainstem), or diastole (when these afferent signals are quiescent). Threat learning was indexed objectively using skin conductance responses (SCRs). During acquisition of threat contingencies, cardiac effects dominated: Stimuli (both CS+ and CS-) presented at systole evoked greater SCR responses, relative to stimuli (both CS+ and CS-) presented at diastole. This difference was amplified in more anxious individuals. Learning of conditioned fear was established by the end of the acquisition phase, which was followed by an extinction phase when unpaired CSs were presented at either the same or switched cardiac contingencies. One day later, electrocutaneous shocks triggered the reinstatement of fear responses. Subsequent presentation of stimuli previously encoded at systole evoked higher SCRs. Moreover, only those participants for whom stimuli had the same cardiac-contingency over both acquisition and extinction phases retained conditioned fear memory (i.e., CS+ > CS-). Our findings reveal two important cardiac afferent effects on threat learning and memory: 1) Cardiac signals bias processing toward threat; and 2) cardiac signals are a context for fear memory; altering this context can disrupt the memory. These observations suggest how threat reactivity may be reinforced and maintained by both acute and enduring states of cardiac arousal. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Parental support of self-regulation among children at risk for externalizing symptoms: Developmental trajectories of physiological regulation and behavioral adjustment.

Children with externalizing symptoms typically show dysregulated arousal when facing emotional challenges and are at risk for antisocial outcomes later in life. The model of emotion socialization (Eisenberg, Cumberland, & Spinrad, 1998) points to supportive emotion-related parenting as central to promoting children's regulatory capability and behavioral adjustment. However, the role of emotion-related parenting is less clear for children living in disadvantaged conditions and already displaying behavioral problems, and little is known about how these parenting practices shape the physiological underpinnings of behavioral adjustment. This study examined the relation between supportive emotion-related parenting and the trajectories of physiological regulation and externalizing symptoms across early school years among 207 children (66% male) from high-risk urban communities, who showed aggressive/oppositional behaviors at school entry. Mothers' supportive emotion-related parenting was observed in kindergarten during structured interactions. Children's respiratory sinus arrhythmia (RSA), an indicator of parasympathetic influence over cardiac arousal, was measured at rest and during an anger scene each year from kindergarten to the 2nd grade. Teacher ratings of externalizing symptoms were also obtained every year. Over time, supportive emotion-related parenting was related to a developmental trend from RSA augmentation toward RSA withdrawal during the anger scene as well as lower risk for escalating externalizing symptoms. The developmental changes of RSA reactivity partially accounted for the relation between parenting and trajectories of externalizing symptoms. Findings underscore the potential of supportive emotion-related parenting for diverting at-risk children from antisocial trajectories by shaping their physiological regulation and behavioral adjustment. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Determinants of Nocturnal Cardiovascular Variability and Heart Rate Arousal Response in Restless Legs Syndrome (RLS)/Periodic Limb Movements (PLMS).

Recent studies have suggested that restless legs syndrome is associated with an increased prevalence of cardiovascular diseases mediated by sympathetic activation occurring during periodic limb movements. The aim of this study was to establish which factors affect the degree of sympathetic activation during the basal condition and during periodic limb movements that may contribute to increased vascular risk. Fifty untreated restless legs syndrome patients aged 62.6 ± 11.1 y, free of cardiovascular diseases, were examined. Heart rate variability was calculated during wakefulness and all sleep stages, during periods with and without periodic limb movements. Heart rate changes before and after periodic limb movement onset were analyzed to assess the arousal response to periodic limb movements. Both analyses took into account the effects of age, gender, periodic limb movement duration, periodic limb movement index, periodic limb movement interval and periodicity, and magnitude of muscular activity (electromyogram power). Compared to periods without periodic limb movements, a significant increase in sympathetic activity occurred in periods with periodic limb movements, independent of age, sex and periodic limb movement characteristics. Data obtained from the cardiac arousal response to periodic limb movements showed that electromyogram power is the factor affecting sympathetic tonus. These results suggest that other factors, such as electromyogram power and individual susceptibility, should be considered in the assessment of the vascular risk related to restless legs syndrome.

Sleep Preserves Physiological Arousal in Emotional Memory

Traumatic experiences are associated with increased emotional arousal. Overnight consolidation strengthens the episodic content of emotional memories, but it is still unclear how sleep influences the associated arousal response. To investigate this question, we compared the effects of sleep and wake on psychophysiological and subjective reactivity during emotional memory retrieval. Participants provided affective ratings for negative and neutral images while heart rate deceleration (HRD) and skin conductance responses (SCRs) were monitored. Following a 12-hour delay of sleep or wakefulness, participants completed an image recognition task where HRD, SCRs and affective ratings were recorded again. HRD responses to previously-encoded (“old”) negative images were preserved after sleep but diminished after wakefulness. No between-group difference in HRD was observed for novel negative images at recognition, indicating that the effects of sleep for old images were not driven by a generalised overnight increase in visceral activity, or circadian factors. No significant effects of sleep were observed for SCRs or subjective ratings. Our data suggest that cardiac arousal experienced at the time of encoding is sensitive to plasticity-promoting processes during sleep in a similar manner to episodic aspects of emotional memory.

The heart of control: Proactive cognitive control training limits anxious cardiac arousal under stress

Research and theory suggest that anxious people employ cognitive control on a relatively late and transient basis. This tendency may impair emotion regulation that depends on early, persistent implementation of cognitive control. We examined whether anxious people could be trained to apply cognitive control proactively (i.e., in advance of goal-related action) and whether such training limited anxiety’s rise during stress. In Study 1, 96 high trait-anxious participants completed proactive or reactive training followed by the Trier Social Stress Test (TSST) with measurement of subjective anxiety, heart rate, and skin conductance level (SCL). In Study 2, 59 high trait-anxious participants completed a proactive or no-instruction training for 4 days and then completed the TSST. For Study 2 but not Study 1, the proactive versus control training was associated with lower stress-related increases in subjective anxiety and heart rate, but not sympathetically mediated SCL. Exercising proactive control may leverage the parasympathetic nervous system to inhibit the escalation of anxious arousal during stress.

High cardiorespiratory fitness in early to late middle age preserves the cortical circuitry associated with brain-heart integration during volitional exercise.

This study tested the hypothesis that high cardiorespiratory fitness (peak oxygen uptake) preserves the cortical circuitry associated with cardiac arousal during exercise in middle- to older-aged individuals. Observations of changes in heart rate (HR) and in cortical blood oxygenation level-dependent (BOLD) images were made in 52 healthy, active individuals (45-73 yr; 16 women, 36 men) across a range of fitness (26-66 ml·kg-1·min-1). Seven repeated bouts of isometric handgrip (IHG) at 40% maximal voluntary contraction force were performed with functional magnetic resonance imaging at 3 T, with each contraction lasting 20 s and separated by 40 s of rest. HR responses to IHG showed high variability across individuals. Linear regression revealed that cardiorespiratory fitness was not a strong predictor of the HR response (r2 = 0.09). In a region-of-interest analysis both the IHG task and the HR time course correlated with increased cortical activation in the bilateral insula and decreased activation relative to baseline in the anterior and posterior cingulate and medial prefrontal cortex (MPFC). t-Test results revealed greater deactivation at the MPFC with higher fitness levels beyond that of guideline-based activity. Therefore, whereas high cardiorespiratory fitness failed to affect absolute HR responses to IHG in this age range, a select effect was observed in cortical regions known to be associated with cardiovascular arousal.NEW & NOTEWORTHY Our first observation suggests that fitness does not strongly predict the heart rate (HR) response to a volitional handgrip task in middle- to older-aged adults. Second, the BOLD response associated with the handgrip task, and with the HR time course, was associated with response patterns in the cortical autonomic network. Finally, whereas high cardiorespiratory fitness failed to affect absolute HR responses to isometric handgrip in this age range, a select effect was observed in cortical regions known to be associated with cardiovascular arousal, beyond that achieved through healthy active living.

A Review on Detection and Treatment Methods of Sleep Apnea.

This paper presents a review on detection and treatment methods of sleep apnea. Sleep apnea is the most common type of breathing-related sleep disorder. It manifests in a variety of behaviours from teeth grinding to night terrors as involuntary night-time events. The most common sleep disorders are narcolepsy, hypersomnia, sleep talking, sleep walking, and bedwetting. Sleep apnea (somnipathy) is a serious sleep disorder that pauses breathing while sleeping. Breathing pauses occur 30 times or more during sleep and it lasts for few seconds to minutes, when normal breathing starts after this pause. Untreated sleep apnea patients stop breathing, which happens up to hundreds of times during sleep that ultimately results in atrial fibrillation, cardiac arousal, stroke, brain tumor and other vascular diseases at the age of 65 that causes death. Smokers are at a greater threat for sleep apnea. Several studies have suggested that a person who smokes more than two packs a day has 40 times the risk of sleep apnea then nonsmokers. This review includes the discussion about detection of sleep apnea from heart rate and respiratory events. The published literature of sleep apnea and methods of treatment are also discussed.

Cardiac autonomic regulation in autism and Fragile X syndrome: a review.

Despite the significance of efforts to understand the biological basis of autism, progress in this area has been hindered, in part, by the considerable heterogeneity in the disorder. Fragile X syndrome (FXS), a monogenic condition associated with high risk for autism, may pave the way for the dissection of biological heterogeneity within idiopathic autism. This article adopts a cross-syndrome biomarker approach to evaluate potentially overlapping profiles of cardiac arousal dysregulation (and broader autonomic dysfunction) in autism and FXS. Approaches such as this, aimed at delineating shared mechanisms across genetic syndromes, hold great potential for improving diagnostic precision, promoting earlier identification, and uncovering key systems that can be targeted in pharmaceutical/behavioral interventions. Biomarker approaches may be vital to deconstructing complex psychiatric disorders and are currently promoted as such by major research initiatives such as the NIMH Research Domain Criteria (RDoC). Evidence reviewed here supports physiological dysregulation in a subset of individuals with autism, as evidenced by patterns of hyperarousal and dampened parasympathetic vagal tone that overlap with the well-documented physiological profile of FXS. Moreover, there is growing support for a link between aberrant cardiac activity and core deficits associated with autism, such as communication and social impairment. The delineation of physiological mechanisms common to autism and FXS could lend insight into relationships between genetic etiology and behavioral endstates, highlighting FMR1 as a potential candidate gene. Research gaps and potential pitfalls are discussed to inform timely, well-controlled biomarker research that will ultimately promote better diagnosis and treatment of autism and associated conditions.

Power modulates over-reliance on false cardiac arousal when judging target attractiveness: the powerful are more centered on their own false arousal than the powerless.

Individuals attempting to label their emotions look for a plausible source of their physiological arousal. Co-occurrence of plausible sources can lead to the misattribution of real (or bogus) physiological arousal, resulting in physically attractive individuals being perceived as more attractive than they actually are. In two experiments, female participants heard bogus heart rate feedback while viewing photos of attractive male models. Compared with low-power and control participants, high-power participants rated reinforced photos (increased heart rate) more attractive than non-reinforced photos (stable heart rate) to a greater extent when they heard their own bogus heart rate feedback (Experiments 1 and 2) and to a lesser extent when they heard a recording of another participant's heart rate (Experiment 2). These findings, which suggest that power increases the tendency to misattribute one's physiological arousal to physically attractive individuals, are discussed with reference to theories linking power and social perception.

Correlations between social-emotional feelings and anterior insula activity are independent from visceral states but influenced by culture.

The anterior insula (AI) maps visceral states and is active during emotional experiences, a functional confluence that is central to neurobiological accounts of feelings. Yet, it is unclear how AI activity correlates with feelings during social emotions, and whether this correlation may be influenced by culture, as studies correlating real-time AI activity with visceral states and feelings have focused on Western subjects feeling physical pain or basic disgust. Given psychological evidence that social-emotional feelings are cognitively constructed within cultural frames, we asked Chinese and American participants to report their feeling strength to admiration and compassion-inducing narratives during fMRI with simultaneous electrocardiogram recording. Trial-by-trial, cardiac arousal and feeling strength correlated with ventral and dorsal AI activity bilaterally but predicted different variance, suggesting that interoception and social-emotional feeling construction are concurrent but dissociable AI functions. Further, although the variance that correlated with cardiac arousal did not show cultural effects, the variance that correlated with feelings did. Feeling strength was especially associated with ventral AI activity (the autonomic modulatory sector) in the Chinese group but with dorsal AI activity (the visceral-somatosensory/cognitive sector) in an American group not of Asian descent. This cultural group difference held after controlling for posterior insula (PI) activity and was replicated. A bi-cultural East-Asian American group showed intermediate results. The findings help elucidate how the AI supports feelings and suggest that previous reports that dorsal AI activation reflects feeling strength are culture related. More broadly, the results suggest that the brain's ability to construct conscious experiences of social emotion is less closely tied to visceral processes than neurobiological models predict and at least partly open to cultural influence and learning.

The manifold effects of positive affect on heart rate variability in everyday life: Distinguishing within-person and between-person associations.

Positive affect (PA) has been related to better health. However, the biological pathways underlying this link are not well understood. Different facets of PA (e.g., low activated vs. high activated) and both state and trait PA might have different effects on physiology. This study aimed to relate low- and high-activated facets of momentary assessed (i.e., state) and aggregated (i.e., trait-like) PA to cardiac vagal tone (heart rate variability; HRV) in everyday life (N = 122, with 3 successive recording days). Aggregated activated PA was associated with higher ambulatory HRV, whereas activated momentary PA was accompanied by lower HRV. Moreover, momentary deactivated PA was accompanied by higher HRV, but aggregated deactivated PA was not. Findings were independent of negative affect and various other demographic and behavioral confounds. Together the findings suggest a more complex picture of the health-related effects of PA. Whereas state-related fluctuations in PA seem to exert both activating and deactivating effects on the heart, activated PA on an aggregated level seems to dampen cardiac arousal, thus suggesting beneficial effects for health.

Sex Differences in the Neural Representation of Pain Unpleasantness

Sex differences in pain perception are still poorly understood, but they may be related to the way the brains of men and women respond to the affective dimensions of pain. Using a matched pain intensity paradigm, where pain intensity was kept constant across participants but pain unpleasantness was left free to vary among participants, we studied the relationship between pain unpleasantness and pain-evoked brain activity in healthy men and women separately. Experimental pain was provoked using transcutaneous electrical stimulation of the sural nerve while pain-related brain activity was measured using somatosensory-evoked brain potentials with source localization. Cardiac responses to pain were also measured using electrocardiac recordings. Results revealed that subjective pain unpleasantness was strongly associated with increased perigenual anterior cingulate cortex activity in women, whereas it was strongly associated with decreased ventromedial prefrontal cortex activity in men. Only ventromedial prefrontal cortex deactivations in men were additionally associated with increased autonomic cardiac arousal. These results suggest that in order to deal with pain's objectionable properties, men preferentially deactivate prefrontal suppression regions, leading to the mobilization of threat-control circuits, whereas women recruit well-known emotion-processing areas of the brain. PerspectiveThis article presents neuroimaging findings demonstrating that subjective pain unpleasantness ratings are associated with different pain-evoked brain responses in men and women, which has potentially important implications regarding sex differences in the risk of developing chronic pain.

Early life stress affects cerebral glucose metabolism in adult rhesus monkeys (Macaca mulatta)

Early life stress (ELS) is a risk factor for anxiety, mood disorders and alterations in stress responses. Less is known about the long-term neurobiological impact of ELS. We used [18F]-fluorodeoxyglucose Positron Emission Tomography (FDG-PET) to assess neural responses to a moderate stress test in adult monkeys that experienced ELS as infants. Both groups of monkeys showed hypothalamic-pituitary-adrenal (HPA) axis stress-induced activations and cardiac arousal in response to the stressor. A whole brain analysis detected significantly greater regional cerebral glucose metabolism (rCGM) in superior temporal sulcus, putamen, thalamus, and inferotemporal cortex of ELS animals compared to controls. Region of interest (ROI) analyses performed in areas identified as vulnerable to ELS showed greater activity in the orbitofrontal cortex of ELS compared to control monkeys, but greater hippocampal activity in the control compared to ELS monkeys. Together, these results suggest hyperactivity in emotional and sensory processing regions of adult monkeys with ELS, and greater activity in stress-regulatory areas in the controls. Despite these neural responses, no group differences were detected in neuroendocrine, autonomic or behavioral responses, except for a trend towards increased stillness in the ELS monkeys. Together, these data suggest hypervigilance in the ELS monkeys in the absence of immediate danger.