What we collectively call “stress” is how we experience our body’s reaction to a stressor. This response is aimed to deal with the current stressor and to prepare for recurrences in the future. The... Show moreWhat we collectively call “stress” is how we experience our body’s reaction to a stressor. This response is aimed to deal with the current stressor and to prepare for recurrences in the future. The stress response is for an important part dependent on glucocorticoid hormones. By and large, the acute response to glucocorticoids is beneficial, but chronic exposure often becomes maladaptive. To improve prevention and treatment of disorders we can develop due to stress, it is important to better understand the effects and working mechanisms of glucocorticoids. While we already possess extensive knowledge regarding glucocorticoids and glucocorticoid receptor signaling, we introduced and studied five “aspects of context”, which we felt address important current misconceptions or gaps of knowledge. Corticosterone was at the center of all the studies we performed, yet the eventual outcome of glucocorticoid receptor activation differed extensively in all experiments. Thus, the context in which corticosterone exerts its effects matters, and it is to researcher to be aware of this when designing new studies and interpreting available data. Whilst our research merely addressed some specific processes, the lessons learned from these experiments can be applied much broader to the biology of glucocorticoid signaling and other nuclear family members. Show less
In contrast to classical conditioning of physiological responses such as immune responses and drug effects, only a limited number of studies investigated classical conditioning of endocrine... Show moreIn contrast to classical conditioning of physiological responses such as immune responses and drug effects, only a limited number of studies investigated classical conditioning of endocrine responses. The present paper is the first systematic review that integrates evidence from animal and human trials regarding the possibility to condition the endocrine responses. Twenty-six animal and eight human studies were included in the review. We demonstrated that there is accumulating evidence that classical conditioning processes are able to influence specific endocrine responses, such as cortocosterone/cortisol and insulin, while more limited evidence exists for other hormones. Animal and human studies were generally consistent in their findings; however, the limited number of human studies makes it difficult to generalize and translate the results of animal research to humans. Next to methodological recommendations for future studies, we suggest several ways how classically conditioned endocrine responses can be used in clinical practice. Show less
Wierenga, L.M.; Bos, M.G.N.; Schreuders, E.; Kamp, F. van der; Peper, J.S.; Tamnes, C.K.; Crone, E.A. 2018
The onset of adolescence in humans is marked by hormonal changes that give rise to secondary sexual characteristics, noted as puberty. It has, however, proven challenging to unravel to what extent... Show moreThe onset of adolescence in humans is marked by hormonal changes that give rise to secondary sexual characteristics, noted as puberty. It has, however, proven challenging to unravel to what extent pubertal changes may have organizing effects on the brain beyond chronological age, as reported in animal studies. The present longitudinal study aimed to characterize the unique effects of age and puberty on subcortical brain volumes and included three waves of data collection at two-year intervals and 680 T1-weighted MRI scans of 271 participants (54% females) aged between 8 and 29 years old. Generalized additive mixed model procedures were used to assess the effects of age, self-report pubertal status and testosterone level on basal ganglia, thalamus, hippocampus, amygdala and cerebellum gray matter volumes. We observed age-related increases in putamen and pallidum volumes, and decreases in accumbens and thalamus volumes, all show larger volumes in boys than girls. Only the cerebellum showed an interaction effect of age by sex, such that males showed prolonged increases in cerebellar volume than females. Next, we showed that changes in self-report puberty status better described developmental change than chronological age for most structures in males, and for caudate, pallidum and hippocampal volumes in females. Furthermore, changes in testosterone level were related to development of pallidum, accumbens, hippocampus and amygdala volumes in males and caudate and hippocampal volumes in females. The modeling approach of the present study allowed us to characterize the complex interactions between chronological age and pubertal maturational changes, and the findings indicate puberty unique changes in brain structure that are sex specific. Show less
Akintola, A.A.; Jansen, S.W.; Wilde, R.B.P.; Hultzer, G.; Rodenburg, R.; Heemst, D. van 2015
There are clear sex differences in incidence and onset of stress-related and other psychiatric disorders in humans. Yet, rodent models for psychiatric disorders are predominantly based on male... Show moreThere are clear sex differences in incidence and onset of stress-related and other psychiatric disorders in humans. Yet, rodent models for psychiatric disorders are predominantly based on male animals. The strongest argument for not using female rodents is their estrous cycle and the fluctuating sex hormones per phase which multiplies the number of animals to be tested. Here, we will discuss studies focused on sex differences in emotionality and cognitive abilities in experimental conditions with and without stress. First, female sex hormones such as estrogens and progesterone affect emotions and cognition, contributing to sex differences in behavior. Second, females respond differently to stress than males which might be related to the phase of the estrous cycle. For example, female rats and mice express less anxiety than males in a novel environment. Proestrus females are less anxious than females in the other estrous phases. Third, males perform in spatial tasks superior to females. However, while stress impairs spatial memory in males, females improve their spatial abilities, depending on the task and kind of stressor. We conclude that the differences in emotion, cognition and responses to stress between males and females over the different phases of the estrous cycle should be used in animal models for stress-related psychiatric disorders. Show less
Gandini, S.; Iodice, S.; Koomen, E.; Pietro, A. di; Sera, F.; Caini, S. 2011
The nuclear symptoms and signs of Huntington__s disease (HD) consist of motor, cognitive and behavioural disturbances. Other less well-known, but prevalent and debilitating features of HD include... Show moreThe nuclear symptoms and signs of Huntington__s disease (HD) consist of motor, cognitive and behavioural disturbances. Other less well-known, but prevalent and debilitating features of HD include unintended weight loss, sleep and circadian rhythm disturbances, as well as autonomic nervous system dysfunction. However, the pathogenesis of these less well-known features of HD is poorly understood and currently no effective treatment options are available. It is thus of paramount importance to elucidate the pathological basis of these symptoms and signs in order to design and apply more effective therapeutic interventions. Recently, substantial dysfunction of the hypothalamus was reported in both human studies and various knock-in and transgenic animal models of HD. The hypothalamus consists of groups of interconnected neuronal nuclei located at the base of the brain that regulate a broad array of physiologic, homeostatic and behavioural activities. Therefore, in this thesis we attempt to substantiate the premise that hypothalamic dysfunction per se, as well as secondary (neuro)endocrine and metabolic alterations could contribute to the pathogenesis of several non-motor symptoms and signs of HD. Show less
The main goal of the present thesis was to study the effects of stress and stress hormones on the retrieval of emotional memories in healthy humans. In addition, we were interested in the effects... Show moreThe main goal of the present thesis was to study the effects of stress and stress hormones on the retrieval of emotional memories in healthy humans. In addition, we were interested in the effects of stress hormones on post-retrieval processes like reconsolidation. That is, are there only acute and temporary effects of stress hormones on memory retrieval, or are there also long-term effects? Studying effects of stress hormones can be done in two ways; either by (experimentally) inducing stress in humans, or by exogenously administering doses of stress hormones. In the present thesis both ways were used. Furthermore, when investigating emotional memories, we can make use of memories that are created in a laboratory setting or those that derive from real life experiences, i.e. autobiographical memories. Again, both methods were investigated. We found acute stress and a single cortisol administration to have direct and long-term impairing effects on memory for neutral and emotional information that was learned and reactivated in a controlled laboratory situation. Future studies should shed more light on the generalizability of these findings to real life settings and clinical practice. Show less
