Research on the psychological and physiological stress-responses have been unable to fully clarify the underlying relationship. The unconscious stress hypothesis proposes that stress-related... Show moreResearch on the psychological and physiological stress-responses have been unable to fully clarify the underlying relationship. The unconscious stress hypothesis proposes that stress-related processes outside of awareness may negatively affect cardiovascular (CV) health by activating and even prolonging physiological stress-responses. This thesis provides a starting point in the exploration of the role of processes outside of awareness in cardiovascular stress research. The eight chapters discuss the findings of a systematic review and a series of experiments, using subliminal priming paradigms and fear conditioning, and address various theoretical and methodological issues to benefit future studies in this area. It seems evident that what is outside of awareness may influence the physiological state, but not necessarily all health-relevant parameters. The physiological changes related to unconscious stress appears to differ between the various stressful stimuli and stressors used. Show less
Background Psychopathy has repeatedly been linked to disturbed associative learning from aversive events (i.e., threat conditioning). Optimal threat conditioning requires the generation of internal... Show moreBackground Psychopathy has repeatedly been linked to disturbed associative learning from aversive events (i.e., threat conditioning). Optimal threat conditioning requires the generation of internal representations of stimulus–outcome contingencies and the rate with which these may change. Because mental representations are imperfect, there will always be uncertainty about the accuracy of representations in the brain (i.e., representational uncertainty). However, it remains unclear 1) to what extent threat conditioning is susceptible to different types of uncertainty in representations about contingencies during the acquisition phase and 2) how representational uncertainty relates to psychopathic features. Methods A computational model was applied to functional neuroimaging data to estimate uncertainty in representations of contingencies (CoUn) and the rate of change of contingencies (RUn), respectively, from brain activation during the acquisition phase of threat conditioning in 132 adolescents at risk of developing antisocial personality profiles. Next, the associations between these two types of representational uncertainty and psychopathy-related dimensions were examined. Results The left and right amygdala activations were associated with CoUn, while the bilateral insula and the right amygdala were associated with RUn. Different patterns of relationships were found between psychopathic features and each type of uncertainty. Callous-unemotional traits and impulsive-irresponsible traits uniquely predicted increased CoUn, while only impulsive-irresponsible traits predicted increased RUn. Conclusions The findings suggest that 1) the insula and amygdala differ in how these regions are affected by different types of representational uncertainty during threat conditioning and 2) CoUn and RUn have different patterns of relationships with psychopathy-related dimensions. Show less
Burger, A.M.; Verkuil, B.; Diest, I. van; Does, W. van der; Thayer, J.F.; Brosschot, J.F. 2016
The Doublecortin-Like Kinase (DCLK) gene is involved in neuronal migration during development. Through alternative splicing the DCLK gene also produces a transcript called Ca2+/calmodulin dependent... Show moreThe Doublecortin-Like Kinase (DCLK) gene is involved in neuronal migration during development. Through alternative splicing the DCLK gene also produces a transcript called Ca2+/calmodulin dependent protein kinase (CaMK)-related peptide (CARP) that is expressed exclusively during adulthood in response to neuronal activity. The function of CARP, however, is poorly understood. To study CARP function, we have generated transgenic mice with over-expression of the CARP transcript in, amongst other brain areas, the hippocampus. We aimed to characterize possible behavioral adaptations of these mice by using a Pavlovian fear conditioning approach. This type of fear conditioning, in which both the hippocampus and amygdala are critically involved, allows studying the formation and extinction of fear related memories. We here report on the behavioral adaptations of two distinct transgenic lines: one with high levels of CARP in the hippocampus and amygdala, whilst the other has high levels of CARP in the hippocampal formation, but not in the amygdala. We tested both mouse lines separately by comparing them to their wild-type littermate controls. We provide evidence suggesting consolidation of contextual fear memories is strengthened in mice of both transgenic lines. (C) 2010 Elsevier Inc. All rights reserved. Show less
