Meeting Summary: Sleep is ubiquitous and a necessity for virtually any organism with some form of a brain. Yet the dominant causes and functions of sleep remain a mystery within species, across species, across development, and across daily cycles of night and day. Moreover, understanding how these different time scales and potentially different functions of sleep at each time scale are able to interact and integrate is a major challenge. For instance, sleep times decrease with body size across species and also decrease with body size as organisms grow from birth to adult. However, the rate of change with body size is very different across phylogeny than it is across ontogeny. In addition, it is intriguing to consider how biological and physical clocks can be coupled together. Biological clocks change with species and age, but the physical clocks of the sun, moon, and seasons are experienced to be the same by all organisms. This is further complicated by the fact that some species live only a few days while others can live for 200 years. Consequently, this working group will focus on the causes, time scales, and consequences of sleep for the following aspects:
• Changes in sleep time across species (evolution and physiology)
• Changes in sleep time as we grow (early and late development)
• Changes in sleep time as we age during adulthood
• Changes in when we sleep (circadian, consolidated, etc.)
• Changes in sleep time within a single sleep cycle (REM and non-REM)
Support for this meeting has been generously provided by the James S. McDonnell Foundation, as part of the SFI Complex Time - Adaptation, Aging, Arrow of Time research theme.