Circadian rhythms have evolved in almost all organisms enabling them to anticipate alternating changes in the environment. As a consequence, the circadian clock controls a broad range of bodily... Show moreCircadian rhythms have evolved in almost all organisms enabling them to anticipate alternating changes in the environment. As a consequence, the circadian clock controls a broad range of bodily functions including appetite, sleep, activity and cortisol levels. The circadian clock synchronizes itself to the external world mainly by environmental light cues and can be disturbed by a variety of factors, including shift-work, jet-lag, stress, ageing and artificial light at night.Interestingly, mood has also been shown to follow a diurnal rhythm. Moreover, circadian disruption has been associated with various mood disorders and patients suffering from depression have irregular biological rhythms in sleep, appetite, activity and cortisol levels suggesting that circadian rhythmicity is crucially involved in the etiology and pathophysiology of depression.The aim of the present review is to give an overview and discuss recent findings in both humans and rodents linking a disturbed circadian rhythm to depression. Understanding the relation between a disturbed circadian rhythm and the etiology of depression may lead to novel therapeutic and preventative strategies. Show less
Psychopathy is a neurodevelopmental disorder that has a highly deleterious effect upon both individuals and society at large. Psychopaths grossly neglect and disrespect the interests of others.... Show morePsychopathy is a neurodevelopmental disorder that has a highly deleterious effect upon both individuals and society at large. Psychopaths grossly neglect and disrespect the interests of others. Their antisocial behavior is thought to originate from a lack of empathy. However, empathy is multidimensional in nature, as evidenced by the considerable heterogeneity in extant theorizing on the subject. Here, we present the "Zipper model of empathy" that reconsiders how both its affective and cognitive components converge in mature empathic behavior. Furthermore, the Zipper model of empathy is expedient for explaining the empathy deficits in psychopathy, insofar as it brings together current theories on the dysfunctional affective components of empathy, violence inhibition, and automatic versus goal-directed attention. According to the literature, the neurobiological underpinnings of these theories are amygdala-centered; however, this article traces this specifically to the basolateral and central amygdala subregions. When viewed together, the cognitive and affective components of empathy are zipped together in a natural fashion in healthy empathic behavior, whereas psychopaths leave the zipper substantially unzipped in pursuit of their purely self-centered goals. Show less
Braunsdorf, M.; Blazquez Freches, G.; Roumazeilles, L.; Eichert, N.; Schurz, M.; Uithol, S. et al. 2021
The ventral tegmental area dopamine (VTA-DA) mesolimbic circuit processes emotional, motivational, and social reward associations together with their more demanding cognitive aspects that involve... Show moreThe ventral tegmental area dopamine (VTA-DA) mesolimbic circuit processes emotional, motivational, and social reward associations together with their more demanding cognitive aspects that involve the mesocortical circuitry. Coping with stress increases VTA-DA excitability, but when the stressor becomes chronic the VTA-DA circuit is less active, which may lead to degeneration and local microglial activation. This switch between activation and inhibition of VTA-DA neurons is modulated by e.g. corticotropin-releasing hormone (CRH), opioids, brain-derived neurotrophic factor (BDNF), and the adrenal glucocorticoids. These actions are coordinated with energy-demanding stress-coping styles to promote behavioral adaptation. The VTA circuits show sexual dimorphism that is programmed by sex hormones during perinatal life in a manner that can be affected by glucocorticoid exposure. We conclude that insight in the role of stress in VTA-DA plasticity and connectivity, during reward processing and stress-coping, will be helpful to better understand the mechanism of resilience to breakdown of adaptation. Show less
Introduction: Cognitive impairment and frailty are important health determinants, independently associated with increased dementia risk. In this meta-analysis we aimed to quantify the association... Show moreIntroduction: Cognitive impairment and frailty are important health determinants, independently associated with increased dementia risk. In this meta-analysis we aimed to quantify the association of the co-occurrence of cognitive impairment no dementia (CIND) and physical frailty with incident dementia.Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used when reporting this review. We performed a systematic search on PubMed, Web of Science, and Embase databases for relevant articles. Longitudinal studies enrolling individuals with both CIND and physical frailty and reporting dementia incidence were eligible. Pooled estimates were obtained through random effect models and Mantel-Haenszel weighting.Results: Out of 3684 articles, five (14302 participants) were included in the meta-analysis. In comparison to participants free from frailty and CIND, the pooled hazard ratio for dementia was 3.83 (95% confidence interval (CI]: 2.64-5.56) for isolated CIND, 1.47 (95%CI: 0.89-2.40) for isolated physical frailty, and 5.36 (95%CI: 3.26-8.81) for their co-occurrence.Discussion: The co-occurrence of cognitive impairment and physical frailty is a clinical marker of incident dementia. Show less
