Psychophysiological response to social stressors : relevance of sex and age

Understanding the factors involved in the psychophysiological response of people in acute stressful situations is crucial to the prevention and treatment of stress-related health problems. We aim to integrate the results of studies investigating the role of sex and age in the inter-individual variability in several biomarkers of the stress response Methods: We summarize the main findings of our research group and other laboratories regarding sex and age-related differences in the psychophysiological response to psychosocial stress. Results: Sexrelated differences in the stress response are observed in blood pressure and cortisol, but not in heart rate, heart rate variability, or salivary alphaamylase. Additionally, age may explain differences in cortisol levels and basal sympathetic nervous system activity. Conclusions: The results highlight the importance of taking sex and age into account in order to understand the stress response and its possible negative effects on health. Antecedentes: entender los factores involucrados en la respuesta psicofisiológica ante situaciones de estrés agudo es crucial para prevenir y tratar problemas de salud relacionados con el estrés. El objetivo es integrar los resultados de estudios en humanos relacionados con el papel del sexo y la edad en las diferencias individuales en la respuesta de estrés en diferentes biomarcadores. Metodología: se integran los principales resultados de nuestro grupo de investigación y de otros laboratorios centrados en las diferencias debidas al sexo y la edad en la respuesta psicofisiológica a situaciones de estrés psicosocial. Resultados: se observan diferencias en la respuesta de estrés entre hombres y mujeres en presión sanguínea y en niveles de cortisol, pero no en frecuencia cardíaca, variabilidad de la frecuencia cardíaca y alfa-amilasa. Además, la edad influye en los niveles de cortisol y en la actividad basal del sistema nervioso simpático. Conclusiones: los resultados ponen de manifiesto la importancia de tener en cuenta el sexo y la edad de los participantes para poder entender la respuesta de estrés y sus posibles efectos en salud

Individual differences in the encoding of contextual details following acute stress:An explorative study

Information processing under stressful circumstances depends on many experimental conditions, like the information valence or the point in time at which brain function is probed. This also holds true for memorizing contextual details (or 'memory contextualization'). Moreover, large interindividual differences appear to exist in (context-dependent) memory formation after stress, but it is mostly unknown which individual characteristics are essential. Various characteristics were explored from a theory-driven and data-driven perspective, in 120 healthy men. In the theory-driven model, we postulated that life adversity and trait anxiety shape the stress response, which impacts memory contextualization following acute stress. This was indeed largely supported by linear regression analyses, showing significant interactions depending on valence and time point after stress. Thus, during the acute phase of the stress response, reduced neutral memory contextualization was related to salivary cortisol level; moreover, certain individual characteristics correlated with memory contextualization of negatively valenced material: (a) life adversity, (b) alpha-amylase reactivity in those with low life adversity and (c) cortisol reactivity in those with low trait anxiety. Better neutral memory contextualization during the recovery phase of the stress response was associated with (a) cortisol in individuals with low life adversity and (b) alpha-amylase in individuals with high life adversity. The data-driven Random Forest-based variable selection also pointed to (early) life adversity-during the acute phase-and (moderate) alpha-amylase reactivity-during the recovery phase-as individual characteristics related to better memory contextualization. Newly identified characteristics sparked novel hypotheses about non-anxious personality traits, age, mood and states during retrieval of context-related information

Stress, the cortisol awakening response and cognitive function

There is evidence that stress-induced disruption of the circadian rhythm of cortisol secretion, has negative consequences for brain health. The cortisol awakening response (CAR) is the most prominent and dynamic aspect of this rhythm. It has complex regulatory mechanisms making it distinct from the rest of the cortisol circadian rhythm, and is frequently investigated as a biomarker of stress and potential intermediary between stress and impaired brain function. Despite this, the precise function of the CAR within the healthy cortisol circadian rhythm remains poorly understood. Cortisol is a powerful hormone known to influence cognition in multiple and complex ways. Studies of the CAR and cognitive function have used varied methodological approaches which have produced similarly varied findings. The present review considers the accumulating evidence linking stress, attenuation of the CAR and reduced cognitive function, and seeks to contextualize the many findings to study populations, cognitive measures, and CAR methodologies employed. Associations between the CAR and both memory and executive functions are discussed in relation to its potential role as a neuroendocrine time of day signal that synchronizes peripheral clocks throughout the brain to enable optimum function, and recommendations for future research are provided

Post-encoding stress does not enhance memory consolidation: The role of cortisol and testosterone reactivity

In contrast to the large body of research on the effects of stress-induced cortisol on memory consolidation in young people, far less attention has been devoted to understanding the effects of stress-induced testosterone on this memory phase. This study examined the psychobiological (i.e., anxiety, cortisol, and testosterone) response to the Maastricht Acute Stress Test and its impact on free recall and recognition for emotional and neutral material. Thirty-seven healthy young men and women were exposed to a stress (MAST) or control task post-encoding, and 24 h later, they had to recall the material previously learned. Results indicated that the MAST increased anxiety and cortisol levels, but it did not significantly change the testosterone levels. Post-encoding MAST did not affect memory consolidation for emotional and neutral pictures. Interestingly, however, cortisol reactivity was negatively related to free recall for negative low-arousal pictures, whereas testosterone reactivity was positively related to free recall for negative-high arousal and total pictures. This study provides preliminary evidence about a different reactivity of testosterone and cortisol to the MAST as well as on their effects on consolidation. Our results suggest a different pattern of relationships between these steroid hormones and the arousal of the negative images

Psychosocial stress affects the acquisition of cerebellar-dependent sensorimotor adaptation

Despite being overlooked in theoretical models of stress-related disorders, differences in cerebellar structure and function are consistently reported in studies of individuals exposed to current and early-life stressors. However, the mediating processes through which stress impacts upon cerebellar function are currently unknown. The aim of the current experiment was to test the effects of experimentally-induced acute stress on cerebellar functioning, using a classic, forward saccadic adaptation paradigm in healthy, young men and women. Stress induction was achieved by employing the Montreal Imaging Stress Task (MIST), a task employing mental arithmetic and negative social feedback to generate significant physiological and endocrine stress responses. Saccadic adaptation was elicited using the double-step target paradigm. In the experiment, 48 participants matched for gender and age were exposed to either a stress (n = 25) or a control (n = 23) condition. Saliva for cortisol analysis was collected before, immediately after, and 10, and 30 min after the MIST. Saccadic adaptation was assessed approximately 10 min after stress induction, when cortisol levels peaked. Participants in the stress group reported significantly more stress symptoms and exhibited greater total cortisol output compared to controls. The stress manipulation was associated with slower learning rates in the stress group, while control participants acquired adaptation faster. Learning rates were negatively associated with cortisol output and mood disturbance. Results suggest that experimentally-induced stress slowed acquisition of cerebellar-dependent saccadic adaptation, related to increases in cortisol output. These ‘proof-of-principle’ data demonstrate that stress modulates cerebellar-related functions

Acute cortisol levels and memory performance in older people with high and normal Body Mass Index

Previous studies have shown that healthy older adults may be less sensitive to the effects of acute cortisol levels on memory performance than young adults. Importantly, being overweight has recently been associated with an increase in both cortisol concentration and cortisol receptors in central tissues, suggesting that Body Mass Index (BMI) may contribute to differences in the relationship between memory and acute cortisol. This study investigates the role of BMI in the relationship between memory performance and acute cortisol levels in older people (M = 64.70 years; SD = 4.24). We measured cortisol levels and memory performance (working memory and declarative memory) in 33 participants with normal BMI (normal BMI = 18.50-24.99) and 36 participants with overweight BMI (overweight BMI = 25-29.99). Overweight BMI participants showed worse performance on word-list learning (p = .036, 95% CI [0.08, 2.18], eta(2)(p) = 0.07). Higher cortisol levels were related to higher proactive interference (beta = .364, p = .016, 95% CI [0.07, 0.66]), and BMI did not moderate any of the relationships investigated. In accordance with previous studies, our results show worse memory performance in individuals with overweight BMI. However, our results do not support the idea that memory performance in older people with higher BMI may be more sensitive to differences in acute cortisol levels than in older people with normal BMI. More research is needed to test this hypothesis with obese individuals (BMI > 30 Kg/cm(2))

Read-React-Respond: An integrative model for understanding sexual revictimization

Females who have been sexually abused in childhood are at significantly higher risk to be revictimized in adolescence and adulthood. Revictimization is associated with a raft of adverse mental and physical health outcomes, and so understanding why victims of childhood sexual abuse are more vulnerable to later sexual assaults has critical implications for their development. It has been hypothesized that sexual abuse in childhood results in reduced ability to recognize and/or respond effectively to sexual threats later in life, but studies examining these ideas have produced inconsistent results. Further, this research has failed to incorporate the powerful physiological reaction elicited by threats of imminent harm to the self, which has the potential to disrupt cognitive processing and coping behavior. In the present paper, we propose a model of revictimization that integrates contemporary theory and research on the biological stress response with cognitive, affective, and behavioral factors believed to be involved in adaptive responding to sexual threats. The model provides a conceptual guide for understanding why females with a history of sexual abuse are more vulnerable to revictimization and offers ideas for improving prevention programs designed to strengthen females’ ability to resist sexual coercion

Stress effects on cognitive function in healthy adults

In our lives, we are constantly exposed to different sources of stress, specifically psychological or social. Our reaction to stress is an adaptive response due to its role in facilitating survival. However, stress can also have immediate and delayed damaging consequences for health, and it is considered one of the most significant health problems of the 21st century, according to the World Health Organization (2001). The impact of stress extends to most of the physiological systems (i.e. cardiovascular, digestive, immune, neuroendocrine or nervous), resulting in numerous diseases. Cognitive problems stand out among the stress effects related to the nervous system. Given the large impact that these problems can have on society in general, and on individuals in particular, the need to understand more about this link is clear. This is one of the reasons for the growing interest in investigating the main mechanisms underlying the stress impact on different cognitive processes, such as memory, attention or executive functions. Several factors related to the characteristics of the stressor, the individual and the cognitive process assessed seem to play an important role in determining the direction of these stress effects. Thus, this thesis focuses on the way stress affects cognition, specifically memory performance, in healthy adults, analyzing the role of some of these factors. The first section of the first chapter discusses the evolution of the stress concept and explains what the stress response is. In the second part, the link between stress and memory is explained, detailing which brain structures are related to the control of the stress response and the cognitive processes. Then, a brief summary of the studies about the effect of acute stress on memory performance is presented. Moreover, the Hypothalamus-Pituitary-Adrenal axis (HPA-axis) in basal conditions (non-stress) is addressed, again summarizing the studies that have investigated the relationship between HPA-axis functioning and cognitive performance. Finally, the chapter ends with the main goals and hypothesis of this thesis and a general description of the material and methods used in the empirical chapters. In the second chapter, the first study is presented. In this study, we examined the effects of stress-prior learning on two types of memory (i.e. non-declarative and declarative memory) in young adults. Here, the material to be remembered is neutral, and the role of sex is considered. Next, in the third chapter of the thesis, following a similar design, the second study carries out a direct comparison of older and young adults. The fourth chapter describes the third study, which investigates the stress effects on memory retrieval. Now, the stressor is applied before the retrieval tasks, and the material to be remembered is neutral and emotional. Again, older and young adults of both sexes are compared. In the last study, the fifth chapter analyzes the relationships between the cortisol awakening response (CAR) and the diurnal cortisol slope (DCS), two different components of the diurnal cortisol cycle, and different memory tasks. The sixth chapter contains a general discussion and the main findings of the aforementioned studies; the strengths and limitations of this thesis and the direction of the next steps in the research on this topic are discussed here. Finally, the seventh chapter presents the main conclusions of the studies included in this thesis

The interaction between stress and chronic pain through the lens of threat learning

Stress and pain are interleaved at multiple levels - interacting and influencing each other. Both are modulated by psychosocial factors including fears, beliefs, and goals, and are served by overlapping neural substrates. One major contributing factor in the development and maintenance of chronic pain is threat learning, with pain as an emotionally-salient threat – or stressor. Here, we argue that threat learning is a central mechanism and contributor, mediating the relationship between stress and chronic pain. We review the state of the art on (mal)adaptive learning in chronic pain, and on effects of stress and particularly cortisol on learning. We then provide a theoretical integration of how stress may affect chronic pain through its effect on threat learning. Prolonged stress, as may be experienced by patients with chronic pain, and its resulting changes in key brain networks modulating stress responses and threat learning, may further exacerbate these impairing effects on threat learning. We provide testable hypotheses and suggestions for how this integration may guide future research and clinical approaches in chronic pain