title: The stress hormone cortisol blocks perceptual learning in humans.
abstract: Cortisol, the primary glucocorticoid (GC) in humans, influences neuronal excitability and plasticity by acting on mineralocorticoid and glucocorticoid receptors. Cellular studies demonstrated that elevated GC levels affect neuronal plasticity, for example through a reduction of hippocampal long-term potentiation (LTP). At the behavioural level, after treatment with GCs, numerous studies have reported impaired hippocampal function, such as impaired memory retrieval. In contrast, relatively little is known about the impact of GCs on cortical plasticity and perceptual learning in adult humans. Therefore, in this study, we explored the impact of elevated GC levels on human perceptual learning. To this aim, we used a training-independent learning approach, where lasting changes in human perception can be induced by applying passive repetitive sensory stimulation (rss), the timing of which was determined from cellular LTP studies. In our placebo-controlled double-blind study, we used tactile LTP-like stimulation to induce improvements in tactile acuity (spatial two-point discrimination). Our results show that a single administration of hydrocortisone (30mg) completely blocked rss-induced changes in two-point discrimination. In contrast, the placebo group showed the expected rss-induced increase in two-point discrimination of over 14%. Our data demonstrate that high GC levels inhibit rss-induced perceptual learning. We suggest that the suppression of LTP, as previously reported in cellular studies, may explain the perceptual learning impairments observed here.
authors.affiliation: Neural Plasticity Lab, Institute for Neuroinformatik, Ruhr-University Bochum, Bochum, Germany; Department of Neurology, University Hospital Bergmannsheil, Ruhr-University Bochum, Germany. Electronic address: hubert.dinse@rub.de.
authors.forename: Hubert R
authors.initials: HR
authors.lastname: Dinse
authors.affiliation: Neural Plasticity Lab, Institute for Neuroinformatik, Ruhr-University Bochum, Bochum, Germany. Electronic address: jan-christoph.kattenstroth@rub.de.
authors.forename: J C
authors.initials: JC
authors.lastname: Kattenstroth
authors.affiliation: Department of Neurology, University Hospital Bergmannsheil, Ruhr-University Bochum, Germany. Electronic address: melanie.lenz@rub.de.
authors.forename: M
authors.initials: M
authors.lastname: Lenz
authors.affiliation: Department of Neurology, University Hospital Bergmannsheil, Ruhr-University Bochum, Germany. Electronic address: martin.tegenthoff@rub.de.
authors.forename: M
authors.initials: M
authors.lastname: Tegenthoff
authors.affiliation: Institute of Cognitive Neuroscience, Department of Cognitive Psychology, Ruhr University Bochum, Germany. Electronic address: oliver.t.wolf@rub.de.
authors.forename: O T
authors.initials: OT
authors.lastname: Wolf
mesh_terms: D000328:Adult; D004193:Discrimination Learning / Q000187:drug effects*; D004311:Double-Blind Method; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects; D009483:Neuropsychological Tests; D055698:Touch Perception / Q000187:drug effects*
chemical_list: D006854:Hydrocortisone
keywords: Cortex; Implicit learning; Long-term potentiation; Repetitive sensory stimulation; Stress hormone cortisol; Tactile acuity