During the FY 2018 funding period, we addressed the following: In collaboration with our colleagues from the Walter Reed Army Institute of Research (T Balkin) and NINDS (D. Picchioni), we applied the L-1-C-11leucine positron emission tomography (PET) method to measure rCPS in human subjects during sleep. To address the restoration hypothesis of sleep, we measure rCPS in the same participant during normal wakefulness, sleep-deprived wakefulness, and sleep. We hypothesize that rCPS is increased during sleep, but that during sleep-deprived wakefulness, rCPS remain at levels comparable to rested wakefulness. Participants undergo the initial scan in the awake, sleep-sated state. Participants are then kept awake over the next 30 h and subsequently undergo a second PET scan in the sleep-deprived but awake state. Participants are then encouraged to sleep in the scanner while they undergo a third scan during slow wave sleep. Participants are healthy male and female volunteers between the ages of 18 and 28 y. We exclude participants with a history of neurological and psychiatric disorders, chronic medical conditions, and sleep disorders. Our preliminary results indicate no differences in rCPS during slow wave sleep. We are preparing a manuscript reporting results of these studies. If protein synthesis during sleep is required for sleep-dependent memory consolidation, we might expect rates of cerebral protein synthesis (rCPS) to increase during sleep in the local brain circuits that support performance on a particular task following training on that task. To measure circuit-specific brain protein synthesis during a daytime nap opportunity, we used the L-1-11Cleucine PET method with simultaneous polysomnography. We trained participants on the texture discrimination task (TDT). This was followed by a nap opportunity during a 11-Cleucine PET scan, and we retested them later in the day after the scan. The TDT is considered retinotopically specific, so we hypothesized that higher rCPS in primary visual cortex would be observed in the trained hemisphere compared to the untrained hemisphere in subjects who were randomized to a sleep condition. Our results indicate that the changes in rCPS in primary visual cortex depended on whether participants were in the wakefulness or sleep condition but were independent of the side of the visual field trained. That is, only in the participants randomized to sleep, rCPS in the right primary visual cortex was higher than in the left regardless of side trained. Other brain regions examined were not so affected. In the participants who slept, performance on the TDT improved similarly regardless of the side trained. Results indicate a regionally selective and sleep-dependent effect that occurs with improved performance on the TDT. A manuscript reporting results of these studies was published this year.
| Picchioni, Dante; Schmidt, Kathleen C; McWhirter, Kelly K et al. (2018) Rates of cerebral protein synthesis in primary visual cortex during sleep-dependent memory consolidation, a study in human subjects. Sleep 41: |
| McWhirter, Kelly K; Morrow, Anne S; Lee, Beth A et al. (2015) A PILOT STUDY ON THE ENCODING OF A PERCEPTUAL LEARNING TASK FOLLOWING SLEEP DEPRIVATION. Percept Mot Skills 121:80-93 |
