223 | Synchronized oscillations in circadian neurons in Drosophila

Neural Circuits and Systems Neuroscience

Author: Marcos Wappner | Email: marcoswappner@gmail.com

Marcos Wappner* , Florencia Fernandez-Chiappe* , Luis G Morelli , Nara I Muraro

1° Biomedicine Research Institute of Buenos Aires – CONICET – Partner Institute of the Max Planck Society

Sleep is an essential behavior in most animals, highly conserved across the animal kingdom. Its timing is regulated by the circadian clock, which in Drosophila comprises around 150 neurons. This work focuses on a cluster of circadian neurons termed LNvs, which play an as-of-yet not fully described role in the regulation of the sleep/wake behavior. LNvs can be further subdivided into large and small LNvs (lLNvs and sLNvs). We performed patch clamp experiments that show sustained oscillations of the membrane potential with frequencies in the order of 0.5Hz, consistently so across individuals. We found that the oscillations disappear upon the exposure to the acetylcholine blocker mecamylamine, and a phase response curve suggests they are exogenously supported. By performing simultaneous patch clamp recordings we found that pairs of similar neurons are highly synchronized, and that the sLNv oscillations lag behind the lLNv oscillations by about a tenth of a cycle. Furthermore, neurons in other regions of the brain were also found to oscillate, and do so at the same frequency than the LNvs, with different degrees of lag, always within a few tenths of a cycle duration. The apparent ubiquity of the oscillations in the fly brain may provide an added layer of complexity to neural information processing, a phenomenon we will study in the future.