Aberrant Light-Induced Depression is Associated with Impaired Sensorimotor Gating in Mice

Toshiaki Haga,Yo Kodera,Junichi Toei,Kenichi Mitsui,Kenichi Osada,Mareki Ohtsuji,Hiroyuki Nishimura

doi:10.4236/wjns.2018.81001

Abstract

Mice subjected to an irregular light-dark cycle are known to lose their capacity to synchronize their behavioral rhythm to environmental light, and to show endophenotypes related to depressive disorders. Here we observed that a susceptible strain of mice (C3H/HeJ) subjected to an irregular 3.5 hr:3.5 hr light-dark cycle showed an enhanced acoustic startle reflex and deficits in prepulse inhibition. As impaired sensorimotor gating is associated with the onset of a variety of mental disorders such as schizophrenia and major depressive disorder, irregular environmental light without circadian photo-entrainment may cause stress that has the potential to be involved in humans’ susceptibility to neuropsychiatric abnormalities.

Highlights

Sleep disorders are commonly associated with prevalent neuropsychiatric disorders such as mood disorders and anxiety disorders [1]
LeGates et al [3] reported that mice subjected to an ultradian cycle consisting of 3.5 hr of light and 3.5 hr of dark (T7) lost their circadian photo-entrainment capacity and showed a rhythm of activity governed by the central biological clock in the suprachiasmatic nuclei (SCN) [4]
In mice as well as in humans, the circadian rhythm of general activity is governed by the central circadian pacemaker that is operated by the neurons in the suprachiasmatic nucleus (SCN) [10]

Summary

Introduction

Sleep disorders are commonly associated with prevalent neuropsychiatric disorders such as mood disorders and anxiety disorders [1]. LeGates et al [3] reported that mice subjected to an ultradian cycle consisting of 3.5 hr of light and 3.5 hr of dark (T7) lost their circadian photo-entrainment capacity and showed a rhythm of activity governed by the central biological clock in the suprachiasmatic nuclei (SCN) [4]. These mice showed depression-like behaviors and learning disability [3]. We observed that in a susceptible strain of mice, the same environmental conditions caused impaired sensorimotor gating

Animals

Experimental Procedure

The Effect of the Aberrant Light-Dark Cycle on the Circadian

Discussion

Conclusion