Circadian rhythms and entrainment

To assess inherent circadian function and its interaction with environmental cues, we monitor wheel-running activity of mice maintained for the most part in constant darkness with the administration of intermittent light pulses. Adult mice are singly housed in cages of conventional size but equipped with running wheels. Food and water are provided ad libitum. Mouse cages are kept under environmentally-controlled conditions in light-tight ventilated chambers at up to 10 cages per chamber. Mice are initially maintained for 1 week in a 12:12light:darkcycle and subsequently switched to constant dark conditions for a maximum of 5 weeks. (In some cases, the transition from light:dark to constant darkness will be preceded by a 24 hr period of constant light.)