Abstract
SignificanceDaily rhythms in the molecular clock, in calcium, and in electrical activity all interact to support the functions of circadian pacemaker neurons. However, the regulatory mechanisms that unify these properties are not defined. Here, we utilize the cellular resolution of the Drosophila circadian neural circuit with technological improvements in light-sheet imaging. We report that individual Drosophila pacemakers display two cophasic rhythms of daily calcium fluctuations. We previously described the first: slow changes in intracellular calcium. The second involves high-frequency calcium fluctuations that depend on the function of the T-type calcium channel. We propose that the fast rhythms, emerging sequentially across the 24-h day, correspond to spontaneous electrical activity patterns displayed by different pacemaker groups.
