Neurons Tell Time

Female fruit fly, Drosophila melanogaster (This work has been released into the public domain by its author, Botaurus at German Wikipedia.)

Our ability to see when it’s light or dark outside helps us tell time and also helps our bodies pattern our daily routines, such as when we eat or sleep – but how do cells in our brain, which are important for creating these patterns, know? The circadian or molecular clock consists of molecules which activate and synchronize neurons that regulate organisms’ behaviors in accordance with the 24-hour light/dark cycle. Liang et al. developed a technique to study the activity of these neurons (by measuring calcium levels within the cells) in brains of live fruit flies. They observed that some neurons are active in the morning while others are active in the evening, corresponding with morning or evening locomotor activities such as flying or walking, and that this activity is regulated by the molecular clock in conjunction with the neuropeptide pigment-dispersing factor (PDF). This system, then, acts as a timing mechanism telling neurons when to become active so that they can initiate behaviors at the right time of day.

Jennifer Lovick (@drjkyl)
Senior Editor, Science in Entertainment, Signal to Noise Magazine
PhD, Molecular, Cell, and Developmental Biology


Liang, X., Holy, T. E. & Taghert, P. H. Synchronous Drosophila circadian pacemakers display nonsynchronous Ca2+ rhythms in vivo. Science. 351, 976-981 (2016). DOI: 10.1126/science.aad3997