The Polar Postdoctoral Research will examine the molecular and neurobiological mechanisms that regulate the persistence of a circadian rhythm in an arctic-breeding songbird, the Lapland Longspur (Calcarius lapponicus). Circadian rhythms are integral to the temporal organization of behavior and physiology of most organisms, and are primarily synchronized by the light-dark cycle of day and night. In polar regions, continuous light or darkness prevails for much of the year, leading to abandonment of circadian rhythmicity in most polar animals. An exception to this rule is arctic-breeding migratory songbirds-- they maintain rhythmicity despite exposure to continuous daylight on their high-latitude breeding grounds. The postdoctoral fellow will receive training in neurobiological techniques to examine patterns of clock gene expression (pPer2) in two circadian oscillators: the hypothalamus and pineal gland. The applicant will (1) correlate clock gene expression with biological rhythms in free-living longspurs, (2) evaluate if rhythms in activity and pPer2 expression are endogenous, and (3) determine if such rhythms entrain to low-amplitude zeitgebers of polar day. The intellectual merit of the proposed work lies in understanding the molecular and neurobiological basis of circadian function in polar animals. The project is the first study to examine time-keeping genes in polar migrants. The broader impacts include funding the stipends for two Alaskan Native high school students as summer field technicians. Research results will have implications for the treatment of seasonal affective disorder in humans. The applicant will receive research and career guidance from two sponsoring scientists.
