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Eye Tracking, Cortisol, and a Sleep vs. Wake Consolidation Delay: Combining Methods to Uncover an Interactive Effect of Sleep and Cortisol on Memory
Published on: June 18, 2014
The cortisol awakening response (CAR): facts and future directions
Eva Fries1, Lucia Dettenborn, Clemens Kirschbaum
1Technische Universität Dresden, Faculty of Science, Department of Psychology, Dresden, Germany.
Abstract:
In humans, the secretion of cortisol from the adrenal glands follows a diurnal cycle with a profound increase after awakening. This increase after awakening, a phenomenon termed the cortisol awakening response (CAR), appears to be a distinct feature of the hypothalamus-pituitary-adrenal (HPA) axis, superimposing the circadian rhythmicity of cortisol secretion. Several studies point towards an important role of the hippocampus and, additionally, other brain structures (e. g. amygdala, prefrontal cortex, suprachiasmatic nucleus) in the regulation of the CAR. There is increasing knowledge that the CAR is influenced by a variety of factors such as gender, health status, and health behavior or stress perception. However, the exact function of the profound cortisol increase after awakening is still not clarified. We hypothesize that the anticipation of the upcoming day is of major relevance for the magnitude of the CAR. The present paper reviews the current knowledge on the neural regulation of the CAR and factors influencing this phenomenon and considerations are addressed concerning the exact function of the CAR.
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