Noise Induces Oscillation and Synchronization of the Circadian Neurons

PLoS One. 2015 Dec 21;10(12):e0145360. doi: 10.1371/journal.pone.0145360. eCollection 2015.

Abstract

The principle clock of mammals, named suprachiasmatic nucleus (SCN), coordinates the circadian rhythms of behavioral and physiological activity to the external 24 h light-dark cycle. In the absence of the daily cycle, the SCN acts as an endogenous clock that regulates the ~24 h rhythm of activity. Experimental and theoretical studies usually take the light-dark cycle as a main external influence, and often ignore light pollution as an external influence. However, in modern society, the light pollution such as induced by electrical lighting influences the circadian clock. In the present study, we examined the effect of external noise (light pollution) on the collective behavior of coupled circadian oscillators under constant darkness using a Goodwin model. We found that the external noise plays distinct roles in the network behavior of neurons for weak or strong coupling between the neurons. In the case of strong coupling, the noise reduces the synchronization and the period of the SCN network. Interestingly, in the case of weak coupling, the noise induces a circadian rhythm in the SCN network which is absent in noise-free condition. In addition, the noise increases the synchronization and decreases the period of the SCN network. Our findings may shed new light on the impact of the external noise on the collective behavior of SCN neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Circadian Clocks / physiology
  • Circadian Rhythm / physiology*
  • Darkness
  • Humans
  • Light / adverse effects*
  • Models, Biological*
  • Neurons / physiology*
  • Suprachiasmatic Nucleus / cytology*
  • Suprachiasmatic Nucleus / physiology

Grants and funding

CG is supported by The Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (QD2015016) [http://www.shmec.gov.cn/] and National Science Foundation of China (11505114) [http://www.nsfc.gov.cn/]. JX is supported by Natural Science Foundation of Zhejiang Province (LQ14A050002) [http://www.zjnsf.gov.cn/] and National Science Foundation of China (11405145) [http://www.nsfc.gov.cn/]. HY is supported by The Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning [http://www.shmec.gov.cn/], National Science Foundation of China (10975099) [http://www.nsfc.gov.cn/] and the innovation Program of Shanghai Municipal Education Commission under Grant No. 13YZ072.