Despite the fact that most animals sleep, it is still unclear what function sleep serves. In humans and other mammals, one of the key functions of sleep is likely to improve learning and the ability to retain what was learned. This is indicated by the fact that sleep deprivation leads to learning and memory deficits. In humans, sleep is made up of sleep cycles that last approximately 90 minutes. Within these cycles, sleep alternates between different types of sleep or sleep stages, such as rapid-eye-movement sleep (REMS) and non-REMS. These stages are present in a specific sequence within each cycle and it is believed that these sequences are important for memory. For this research, we will study a laboratory animal model (the rat) in which we can experimentally disrupt the normal sequence of sleep stages without inducing sleep deprivaation. We predict that this disruption will result in deficits in memory, providing evidence for the role of a normal sequence of sleep stages in learning processes. We will also study the molecular mechanisms by which this effect on learning may take place. Our studies will help understand how challenges to normal sleep, that are a common feature of our modern society, affect learning and may help develop strategies to improve learning performance in people that are commonly exposed to sleep disruptions. This project will also include the training of undergraduate and graduate students in research methods and techniques.
