title: Multi-stability of circadian phase wave within early postnatal suprachiasmatic nucleus.
abstract: The suprachiasmatic nucleus (SCN) is a group of cells that functions as a biological master clock. In different SCN cells, oscillations of biochemical markers such as the expression-level of clock genes, are not synchronized but instead form slow circadian phase waves propagating over the whole cell population spatio-temporal structure is a fixed property set by the anatomy of a given SCN. Here, we show that this is not the case in early postnatal SCN. Earlier studies presumed that their Based on bioluminescence imaging experiments with Per2-Luciferase mice SCN cultures which guided computer simulations of a realistic model of the SCN, we demonstrate that the wave is not unique but can be in various modes including phase- coherent oscillation, crescent-shaped wave, and most notably, a rotating pinwheel wave that conceptually resembles a wall clock with a rotating hand. Furthermore, mode transitions can be induced by a pulse of 38.5 °C temperature perturbation. Importantly, the waves support a significantly different period, suggesting that neither a spatially-fixed phase ordering nor a specialized pacemaker having a fixed period exist in these studied SCNs. These results lead to new important questions of what the observed multi-stability means for the proper function of an SCN and its arrhythmia.
authors.affiliation: Department of Physics, Korea University, Seoul, 136-713, Korea.
authors.forename: Byeongha
authors.initials: B
authors.lastname: Jeong
authors.affiliation: Department of Physics, Korea University, Seoul, 136-713, Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Hong
authors.affiliation: Department of Physics, Korea University, Seoul, 136-713, Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Han Kyoung
authors.initials: HK
authors.lastname: Choe
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Kyungjin
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Physics, Korea University, Seoul, 136-713, Korea.
authors.forename: Kyoung J
authors.initials: KJ
authors.lastname: Lee
mesh_terms: D000200:Action Potentials; D000818:Animals; D000831:Animals, Newborn; D001683:Biological Clocks / Q000502:physiology; D058256:Brain Waves; D002940:Circadian Rhythm / Q000502:physiology*; D051379:Mice; D008954:Models, Biological; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D013696:Temperature