William C. Dement Retreat 2009: SHY, PVT, mTOR, and PPD

The 3 day sleep/circadian retreat held in the scenic W. Alton Jones Campus was “acronymonyous.” In addition to the impressive 10 minute presentations given by the Dement fellows, including discussions on the evolution of sleep and sleep in autistic children, the young investigators were off the hook. Dr. Erin Henlon, a post-doc in Ciara Chirelli and Julio Tuononi’s lab at Wisconsin-Madison, nicely summarized the role of BDNF in the learning process, and the SHY theory of synaptic plasticity across sleep and wake; during the waking day, there is incredibly high synaptic potentiation (LTP), and rewiring of synapses that are facilitated through mGlu1 activity. During sleep, LTP across wake is counterbalanced by synaptic depotentiation (LTD) mediated through the phosphorylation of serine. This suggests that sleep resets neuronal processing, serving as a protective mechanism against overstimulation and subsequent neuronal death.

Dr. Dan Mollicone from Pulsar Informatics in Philly uses mathematical modeling to explain detriments in performance related to sleep debt and shifted circadian phases. His model is incredibly reliable; he assured us that he could spend a day in the international terminal at JFK, and know which time zone the sleepy, jet-lagged traveler had arrived from based on his/her performance on the psychomotor vigilance test (PVT); a simple, Gameboy-esque device used to test reaction times. The bottom line is that even though a sleepy traveler may objectively appear alert after taking the PVT at one time of the day, this above-average performance can drastically change within 2 hours. Hence, the circadian timing system is a potent mediator of wakefulness and sleepiness.

Dr. Jonathan Lipton from Harvard Medical School is a neuroscientist/neurologist (M.D./Ph.D.) who balances research and clinical practice. He spends most of his week studying the circadian expression of mTOR, the mammalian target of rapamycin that mediates cell growth and apoptosis, and possibly responsible for the etiology of cancer, and one day diagnosing pediatric sleep disorders . His clinical passion is the role of sleep in the onset and perpetuation of autism.

Finally, Dr. Hawley Montgomery-Downs (bonus points for the awesome name) studies sleep in women post-child birth. Poor sleep following child birth is independent of time in bed and total sleep time. It’s sleep fragmentation across the night that leads to severe sleepiness. As Dr. “The Crusader Dement” has recapitulated over and over again…SLEEPINESS IS RED ALERT! This retreat he even brought us mini squirt guns with his motto engraved on the side. Handy for rest stops…..

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