Patricia Sollars, PhDAssistant Professor Phone: 970-491-0499 Member Education |
Research Interests -- Chronobiology and Sleep
The hypothalamic suprachiasmatic nucleus (SCN) plays a fundamental role in the generation of circadian rhythms in mammals. It is well-established that the SCN has the capacity to generate intrinisic oscillations with a period in the range of 24 hours per cycle, and that it can drive and/or synchronize behavioral and physiological circadian rhythmicity by means of effector circuits to other parts of the brain. The work currently underway in my laboratory is directed at a two-fold analysis of the extent to which the SCN functions autonomously as the mammalian biological clock.
The primary technique employed is a cross-species neural transplantation procedure in which an SCN-ablated animal of one species receives a fetal hypothalamic graft containing the SCN of another species. Because several fundamental properties of circadian rhythmicity have species-typical characteristics, this model allows an analysis of the extent to which those properties are regulated or determined strictly by the SCN. Moreover, the hypothalamic heterograft model allows us to conduct a direct neuranatomical investigation of the full extent of graft/host integration through immunocytochemical techniques that make use of species-specific monoclonal antibodies.
In correlation with these studies, we have recently expanded our efforts and have begun an examination of the circadian regulation of the sleep/wake cycle. Sleep is currently thought to be regulated by both a sleep-homeostatic process (Process S) and by oscillations in the endogenous circadian clock (Process C). Like the circadian clock, certain functions within sleep display species-typical characteristics, including total sleep time, sleep/wake amplitude and the property of diurnality/nocturnality. We are now applying the hypothalamic heterograft model in an attempt to determine the extent to which the species of the clock (underlying Process C) influences the species-typical characteristics of sleep regulation. These studies employ combined analyses conducted at a variety of levels, incorporating behavioral, electoencephalographic, electrophysiological and neuroanatomical data.
Representative Publications
Sollars PJ, Kimble DP, Pickard GE. 1995. Restoration of circadian behavior by anterior hypothalamic heterografts. J Neurosci 15:2109-2122.
Mackiewicz M, Sollars PJ, Ogilvie MD, Pack AI. 1996. Modulation of IL-1B gene expression in the rat CNS during sleep deprivation. Neuroreport 7:529-533.
Sollars PJ, Ogilvie MD, Rea MA, Pickard GE. 2002. 5-HT1B receptor knockout mice exhibit an enhanced response to constant light. J Biol Rhythms 17:428-437.
