From U Pennsylvania: Aging in mice reduces the ability to sustain sleep/wake states

PLoS One. 2013 Dec 16;8(12):e81880. doi: 10.1371/journal.pone.0081880.

Aging in mice reduces the ability to sustain sleep/wake States.

Wimmer ME¹, Rising J², Galante RJ³, Wyner A², Pack AI⁴, Abel T⁵.

Author information

• ¹Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America ; Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
• ²Statistics Department, The Wharton School, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
• ³Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
• ⁴Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America ; Division of Sleep Medicine, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
• ⁵Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America ; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

Abstract

One of the most significant problems facing older individuals is difficulty staying asleep at night and awake during the day. Understanding the mechanisms by which the regulation of sleep/wake goes awry with age is a critical step in identifying novel therapeutic strategies to improve quality of life for the elderly. We measured wake, non-rapid eye movement (NREM) and rapid-eye movement (REM) sleep in young (2-4 months-old) and aged (22-24 months-old) C57BL6/NIA mice. We used both conventional measures (i.e., bout number and bout duration) and an innovative spike-and-slab statistical approach to characterize age-related fragmentation of sleep/wake. The short (spike) and long (slab) components of the spike-and-slab mixture model capture the distribution of bouts for each behavioral state in mice. Using this novel analytical approach, we found that aged animals are less able to sustain long episodes of wakefulness or NREM sleep. Additionally, spectral analysis of EEG recordings revealed that aging slows theta peak frequency, a correlate of arousal. These combined analyses provide a window into the mechanisms underlying the destabilization of long periods of sleep and wake and reduced vigilance that develop with aging.