1. Ghrelin modulates encoding-related brain function without enhancing memory formation in humans.
- Author
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Kunath N, Müller NCJ, Tonon M, Konrad BN, Pawlowski M, Kopczak A, Elbau I, Uhr M, Kühn S, Repantis D, Ohla K, Müller TD, Fernández G, Tschöp M, Czisch M, Steiger A, and Dresler M
- Subjects
- Adult, Brain diagnostic imaging, Cognition drug effects, Cross-Over Studies, Double-Blind Method, Ghrelin administration & dosage, Humans, Magnetic Resonance Imaging, Male, Memory, Long-Term drug effects, Mental Recall drug effects, Young Adult, Brain drug effects, Brain physiology, Cognition physiology, Connectome methods, Ghrelin pharmacology, Memory, Long-Term physiology, Mental Recall physiology
- Abstract
Ghrelin regulates energy homeostasis in various species and enhances memory in rodent models. In humans, the role of ghrelin in cognitive processes has yet to be characterized. Here we show in a double-blind randomized crossover design that acute administration of ghrelin alters encoding-related brain activity, however does not enhance memory formation in humans. Twenty-one healthy young male participants had to memorize food- and non-food-related words presented on a background of a virtual navigational route while undergoing fMRI recordings. After acute ghrelin administration, we observed decreased post-encoding resting state fMRI connectivity between the caudate nucleus and the insula, amygdala, and orbitofrontal cortex. In addition, brain activity related to subsequent memory performance was modulated by ghrelin. On the next day, however, no differences were found in free word recall or cued location-word association recall between conditions; and ghrelin's effects on brain activity or functional connectivity were unrelated to memory performance. Further, ghrelin had no effect on a cognitive test battery comprising tests for working memory, fluid reasoning, creativity, mental speed, and attention. In conclusion, in contrast to studies with animal models, we did not find any evidence for the potential of ghrelin acting as a short-term cognitive enhancer in humans., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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