Polyphasic circadian neural circuits drive differential activities in multiple downstream rhythmic centers

Circadian pacemaker neurons in the Drosophila brain exhibit morning, evening, and mid-day rhythmic activity.

• Rhythmic activity in dopaminergic and peptidergic neurons is widespread and regulated by clock activity within a 150-cell pacemaker network.
• Different subgroups of circadian pacemakers correspond to specific phases: morning (M), evening (E), and mid-day (MD).
• Outputs from morning and evening pacemakers converge to influence specific downstream neurons involved in activity regulation.
• Evening pacemakers specifically control the activity of evening-active neurons.
• A third phase of activity, mid-day, is regulated by l-LNv pacemakers, affecting mid-day active neurons and distinct neurosecretory cell types.
• The Drosophila circadian pacemaker network functions as a polyphasic rhythm generator, organizing various daily behavior patterns.

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