Jens C Pruessner’s research while affiliated with University of Konstanz and other places

While Early Live Adversity (ELA) is a known risk factor for mental and physical diseases, the investigation into the mechanisms behind this connection is ongoing. In the present study, we investigated whether ELA blunts the relaxation response in healthy adults. Using a within-subjects design, we employed a paced breathing exercise (four seconds inhale, six seconds exhale) and a 360° nature video as relaxation interventions while measuring physiological relaxation using heart rate variability and subjective relaxation using the Relaxation State Questionnaire. A total of 103 participants (63.11% female; agemean = 22.73 ± 3.43 years) completed the Parental Bonding Instrument and the Childhood Trauma Questionnaire to assess ELA retrospectively. For subjective relaxation, a blunted relaxation reaction was associated with lower scores of paternal care and higher scores of paternal overprotection, physical abuse, physical neglect, and emotional abuse. For heart rate variability emotional abuse in interaction with nicotine consumption was related to a blunted relaxation response. This indicates that experiencing ELA negatively affects the relaxation capability in a healthy sample and emphasizes the importance of assessing relaxation at a physiological and subjective level.

Mitochondrial Dysregulation in the Frontal Cortex as Biomarker for Psychopathology and Cognition

Hyperglycemia affects cardiac activity at rest, but its effect on cardiac reactivity has not been investigated extensively. While glucose increases hormonal stress responses without changing cardiac stress reactivity, less is known about the interaction of glucose and relaxation interventions on cardiac reactivity. In the present study, we investigated the interaction of glucose administration and a standardized massage intervention on psychophysiological relaxation and sustained attention. Ninety-four participants (age mean = 22.84 years, SD = 2.53 years; 71.28% female) were randomly assigned to consume a drink containing glucose, or pure water before receiving a standardized massage or resting. Directly after the manipulation, they completed the d2 sustained attention test. We repeatedly assessed blood glucose and mood and recorded an electrocardiogram (ECG) and impedance cardiography (ICG) throughout. Root mean square of successive differences (RMSSD) and high-frequency heart rate variability (HF-HRV) were used as a measure of parasympathetic activity, and pre-ejection period (PEP) indexed sympathetic activity. Our preregistered analyses showed that both relaxation interventions increased PNS activity and decreased arousal. Glucose activated the SNS and prevented SNS withdrawal in response to the massage. However, it did not modulate PNS or affective reactivity to the interventions. While cardiac reactivity was not related to sustained attention, higher blood glucose was linked to higher concentration performance and accuracy in explorative analyses. The results provide further support for the autonomic space model demonstrating independence of SNS and PNS regulation depending on the type of manipulation. They may further our understanding of the links between glucose metabolism and autonomic functioning.

In any therapeutic setting, the outcome depends in part on the therapeutic alliance, characterized by mutual understanding, empathy and trust among the participants, which also manifests itself through physiological synchronization (PS) processes involving breathing, heart, and brain. This study examined the dynamics of heart rate variability (HRV) synchronization patterns during horse-assisted therapy. We explored the impact of horse preference of the therapist, and levels of early life adversity (ELA) on PS relationships across participants, riding therapists and therapy horses. Our sample of 43 participants engaged in standardized horse-assisted therapy sessions facilitated by three riding therapists and four therapy horses. PS was operationalized through cross-wavelet power analyses across the different dyads. The results showed that the riding therapist's preference for a particular therapy horse was associated with less HRV synchronization between this therapy horse and the respective riding therapist. Strong synchronization between horse and therapist was associated with strong synchronization between horse and participant and between therapist and participant. We found an association between ELA and HRV synchronization between participants and therapists, with HRV synchronization being lower in individuals with higher levels of ELA. This effect of ELA was not found for HRV synchronization between participants and horses. These findings contribute to a better understanding of the therapeutic mechanisms underlying horse-human interactions and have implications for optimizing therapeutic interventions in clinical settings.

Sense of Okayness (SOK) is an emerging concept that describes a person’s ability to remain stable and unshaken in the face of life transitions and hardships. This quality enables effective stress regulation and heightened tolerance to uncertainty. To investigate the possible role of the parasympathetic nervous system (PNS) in mediating the relationship between SOK and stress regulation among older individuals, an analytical sample of N = 69 participants (74% women) with a mean age of 78.75 years (SD age = 6.78) was recruited for a standardized cognitive assessment and stress induction. Baseline heart rate variability (HRV), measured via electrocardiogram (ECG), and SOK assessments were conducted prior to stress induction, along with a baseline cognitive evaluation. Subsequently, participants were subjected to a psychosocial stress paradigm, followed by either a 30-minute SOK elevation intervention (n = 40) or a control condition with nature sounds (n = 29). A second cognitive assessment was administered post-intervention, with continuous HRV measurement through ECG. The results revealed significant HRV changes due to the experimental intervention, though no significant differences were observed between the SOK intervention and control groups. Interestingly, individuals with high trait SOK displayed more stable HRV trajectories, exhibiting a smaller decline during the stress intervention and a milder increase during both the stressor and SOK intervention phases. Overall, these findings do suggest a significant association between SOK, parasympathetic activity, and stress reactivity. These results prompt further investigation into whether personality patterns, such as a strong SOK, may be linked to reduced vagal reactivity and better coping in old age.

Purpose Early-life adversity (ELA) affects health by altering the hypothalamic–pituitary–adrenal (HPA) axis. Most studies show that ELA blunts HPA responsivity while others show the opposite. To explain this inconsistency, researchers investigate factors that alter associations between ELA and HPA responsivity. One factor could be conditions that participants encounter before exposure to stressors. Life-history theory suggests ELA alters HPA function by signalling high mortality. Similarly, death thoughts signal acute mortality. Research suggests that thinking about death induces behaviors typical of ELA subjects. We therefore tested whether death thoughts before acute stress mimics the effects of ELA on HPA responsivity. Methods One hundred twenty eight healthy young men were classified as high or low ELA based on retrospective self-report, and then primed with death thoughts (experimental group) or completed neutral questionnaires (control group). They then underwent a psychosocial stress task. Salivary cortisol was sampled repeatedly to assess HPA responsivity to stress. Results In the control group, higher ELA correlated with lower cortisol responsivity. In the experimental group, subjects with high ELA did not show altered cortisol responsivity, but low ELA participants displayed significantly blunted responsivity in response to death thoughts. Thus, low ELA participants primed with death thoughts resembled high ELA participants not exposed to death thoughts. Conclusion Our findings suggest that subtle death cues present in the testing environment may confound associations between ELA and HPA function and should be controlled for in future studies. We discuss how life-history theory could explain how both long-term (ELA) and acute (mortality salience) experiences alter HPA function.

In any therapeutic setting, the success depends in part on the therapeutic allience, manifesting itself through mutual understanding, empathy and trust across participants, whether human or equine. This intimate and subjective feeling of connection can also be observed at the physiological level through synchronization processes involving breathing, heart and brain. In the current study, we investigated heart rate variability (HRV) synchronization during horse-assisted therapy, focusing on the part of the session where participants were lying prone on the horses’ back. We explored relationships across participants, riding therapists and therapy horses through continuous HRV recordings and self-reported assessments of early life adversity. A sample of 43 participants (10 healthy female participants in a control group and 33 women with psychiatric disorders in a patient group), engaged in standardized sessions facilitated by three riding therapists and four therapy horses. HRV synchronization was characterized through wavelet coherence analyses across the different dyads. Multi-level model comparisons supported the hypothesis that HRV synchronization between therapy horse and riding therapist positively influenced both HRV synchronization between therapy horse and participant and HRV synchronization between riding therapist and participant. These findings emphasize the interdependence of physiological states within the therapeutic triad, highlighting the contribution of the connection between therapy horse and riding therapist on the overall physiological coherence. Furthermore, analyses revealed early life adversity as a significant factor affecting synchronization processes between participants and riding therapists but not between participants and therapy horses. This finding underscores the broader psychophysiological implications of early life experiences.

We switch between states of “fight/flight/freeze” and “rest/digest” while coping with stressors and subsequent recovery. While previous studies have contributed evidence that factors like chronic stress or early-life adversities (ELA) can affect the psychophysiological stress response and constitute a risk factor for mental diseases, less is known about whether the psychophysiological relaxation response is also affected by these factors, thus offering an alternative explanation of pathogenesis. N = 100 participants (53% female) were grouped based on experience of no (n = 35), one (n = 32), or two (n = 33) risk factors, defined as chronic stress (Perceived Stress Scale), ELA (Parental Bonding Instrument), and subclinical symptoms of depression (Beck Depression Inventory) or anxiety (Beck Anxiety Inventory). N = 51 participants underwent two relaxation interventions, diaphragmatic breathing (DB) and guided imagery (GI), in counterbalanced order. Participants in the control condition (n = 49) read magazines. Heart rate, heart rate variability (continuous electrocardiogram) as well as questionnaires were assessed throughout the whole study. Preliminary results suggest that DB, but not GI, resulted in a significantly greater relaxation response compared to the control condition. The number of risk factors did not modulate the relaxation response to both interventions. Further results will be presented and discussed at the conference. Our findings contribute to the question of whether there are differences in the physiological relaxation response dependent on experienced risk factors. This will broaden our understanding of possible developmental mechanisms of physiological and psychological diseases and might offer a starting point for preventive interventions.

Background The hippocampal-to-ventricle ratio (HVR) is a biomarker of medial temporal atrophy, particularly useful in the assessment of neurodegeneration in diseases such as Alzheimer’s disease (AD). To minimize subjectivity and inter-rater variability, an automated, accurate, precise, and reliable segmentation technique for the hippocampus (HC) and surrounding cerebro-spinal fluid (CSF) filled spaces — such as the temporal horns of the lateral ventricles — is essential. Methods We trained and evaluated three automated methods for the segmentation of both HC and CSF (Multi-Atlas Label Fusion (MALF), Nonlinear Patch-Based Segmentation (NLPB), and a Convolutional Neural Network (CNN)). We then evaluated these methods, including the widely used FreeSurfer technique, using baseline T1w MRIs of 1,641 participants from the AD Neuroimaging Initiative study with various degree of atrophy associated with their cognitive status on the spectrum from cognitively healthy to clinically probable AD. Our gold standard consisted in manual segmentation of HC and CSF from 80 cognitively healthy individuals. We calculated HC volumes and HVR and compared all methods in terms of segmentation reliability, similarity across methods, sensitivity in detecting between-group differences and associations with age, scores of the learning subtest of the Rey Auditory Verbal Learning Test (RAVLT) and the Alzheimer’s Disease Assessment Scale 13 (ADAS13) scores. Results Cross validation demonstrated that the CNN method yielded more accurate HC and CSF segmentations when compared to MALF and NLPB, demonstrating higher volumetric overlap (Dice Kappa = 0.94) and correlation (rho = 0.99) with the manual labels. It was also the most reliable method in clinical data application, showing minimal failures. Our comparisons yielded high correlations between FreeSurfer, CNN and NLPB volumetric values. HVR yielded higher control:AD effect sizes than HC volumes among all segmentation methods, reinforcing the significance of HVR in clinical distinction. Associations The positive association with age was significantly stronger for HVR compared to HC volumes on all methods except FreeSurfer. Memory associations with HC volumes or HVR were only significant for individuals with mild cognitive impairment. Finally, the HC volumes and HVR showed comparable negative associations with ADAS13, particularly in the mild cognitive impairment cohort. Conclusion This study provides an evaluation of automated segmentation methods centered to estimate HVR, emphasizing the superior performance of a CNN-based algorithm. The findings underscore the pivotal role of accurate segmentation in HVR calculations for precise clinical applications, contributing valuable insights into medial temporal lobe atrophy in neurodegenerative disorders, especially AD. Authorship Sofia Fernandez-Lozano: Conceptualization, Methodology, Software, Investigation, Writing – Original Draft, Visualization. Vladimir Fonov: Software, Data Curation. Dorothee Schoemaker: Resources, Writing – Review & Editing. Jens Pruessner: Resources, Writing – Review & Editing. Olivier Potvin: Resources, Writing – Review & Editing. Simon Duchesne: Resources, Writing – Review & Editing. D. Louis Collins: Conceptualization, Writing – Review & Editing, Supervision.