title: Ascent to moderate altitude impairs overnight memory improvements.
abstract: Several studies showed beneficial effects of sleep on memory performance. Slow waves, the electroencephalographic characteristic of deep sleep, reflected on the neuronal level by synchronous slow oscillations, seem crucial for these benefits. Traveling to moderate altitudes decreases deep sleep. In a randomized cross-over design healthy male subjects performed a visuo-motor learning task in Zurich (490 m) and at Davos Jakobshorn (2590 m) in random order. Memory performance was assessed immediately after learning, before sleep, and in the morning after a night of sleep. Sleep EEG recordings were performed during the nights. Our findings show an altitude induced reduction of sleep dependent memory performance. Moreover, this impaired sleep dependent memory performance was associated with reduced slow wave derived measures of neuronal synchronization. Our results are consistent with a critical role of slow waves for the beneficial effects of sleep on memory that is susceptible to natural environmental influences.
authors.affiliation: University Children's Hospital Zurich, Switzerland; Neuroscience Center Zurich (ZNZ), Switzerland.
authors.forename: Noemi
authors.initials: N
authors.lastname: Tesler
authors.affiliation: Pulmonary Division, University Hospital Zurich, Switzerland.
authors.forename: Tsogyal D
authors.initials: TD
authors.lastname: Latshang
authors.affiliation: Pulmonary Division, University Hospital Zurich, Switzerland.
authors.forename: Christian M
authors.initials: CM
authors.lastname: Lo Cascio
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland; Institute of Pharmacology and Toxicology, University of Zurich, Switzerland.
authors.forename: Katrin
authors.initials: K
authors.lastname: Stadelmann
authors.affiliation: Pulmonary Division, University Hospital Zurich, Switzerland.
authors.forename: Anne-Christin
authors.initials: AC
authors.lastname: Stoewhas
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland; Pulmonary Division, University Hospital Zurich, Switzerland.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Kohler
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland; Pulmonary Division, University Hospital Zurich, Switzerland.
authors.forename: Konrad E
authors.initials: KE
authors.lastname: Bloch
authors.affiliation: Neuroscience Center Zurich (ZNZ), Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland; Institute of Pharmacology and Toxicology, University of Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Achermann
authors.affiliation: University Children's Hospital Zurich, Switzerland; Neuroscience Center Zurich (ZNZ), Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland; University Clinics for Child and Adolescent Psychiatry, Zurich, Switzerland. Electronic address: reto.huber@kispi.uzh.ch.
authors.forename: Reto
authors.initials: R
authors.lastname: Huber
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D000531:Altitude; D058256:Brain Waves / Q000502:physiology; D018592:Cross-Over Studies; D006801:Humans; D007858:Learning; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D055815:Young Adult
keywords: Learning; Memory; Moderate altitude; Sleep; Slow wave sleep