Masking of a circadian behavior in larval zebrafish involves the thalamo-habenula pathway

Qian Lin,Suresh Jesuthasan

doi:10.1038/s41598-017-04205-7

Abstract

Changes in illumination can rapidly influence behavior that is normally controlled by the circadian clock. This effect is termed masking. In mice, masking requires melanopsin-expressing retinal ganglion cells that detect blue light and project to the thalamus. It is not known whether masking is wavelength-dependent in other vertebrates, nor is it known whether the thalamus is also involved or how it influences masking. Here, we address these questions in zebrafish. We find that diel vertical migration, a circadian behavior in larval zebrafish, is effectively triggered by blue, but not by red light. Two-photon calcium imaging reveals that a thalamic nucleus and a downstream structure, the habenula, have a sustained response to blue but not to red light. Lesioning the habenula reduces light-evoked climbing. These data suggest that the thalamo-habenula pathway is involved in the ability of blue light to influence a circadian behavior.

Highlights

Light has profound effects on animal behavior, independent of visual perception
By expressing ß-galactosidase[8] or Cre-recombinase[9] in the melanopsin locus of mice, or by using viral-mediated tracing[10], it has been shown that melanopsin-expressing retinal ganglion cells (mRGCs) innervate multiple targets such as the suprachiasmatic nucleus (SCN), olivary pretectal nucleus as well as thalamic nuclei including the intergeniculate leaflet (IGL) and ventral lateral geniculate nucleus
We provide evidence that blue light can drive vertical migration in larval zebrafish

Summary

Introduction

Light has profound effects on animal behavior, independent of visual perception. One effect is to influence locomotor activity that is normally under the control of the circadian clock[1,2,3,4]. We tested whether UV light is able to mask vertical migration of larval zebrafish.

Results

Conclusion