Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.07.330282v1?rss=1 Authors: Obleser, J., Kreitewolf, J., Vielhauer, R., Lindner, F., David, C., Oster, H., Tune, S. Abstract: Perceptual abilities fluctuate on time scales of seconds or minutes. However, it is unclear how slower, circadian neurobiological rhythms such as the expression of glucocorticoid (GC) hormones modulate our perceptual abilities. Here, we show that phasic, moderate increases in GC availability prove beneficial to auditory discrimination. In an age-varying sample of N = 68 healthy human participants, we characterise the covariation of saliva cortisol with perceptual sensitivity in an auditory pitch-discrimination task at five time points across the sleep--wake cycle. First, momentary saliva cortisol levels were captured well by the time relative to the wake-up cycle and overall sleep duration. Second, within individuals, higher cortisol levels just prior to behavioural testing improved participant's pitch discrimination abilities, expressed as a steepened psychometric curve. This effect of glucocorticoids on perceptual sensitivity held under a set of statistical control models. Our results pave the way for more in-depth studies on neuroendo-crinological determinants of sensory encoding and perception. Copy rights belong to original authors. Visit the link for more info