Fig. 2. Extra-clock ultradian oscillators synchronize bursting.

(A) Left, representative rhythmic bursts in ITP-LN_d from per⁰ (top) and pdf⁰¹ (bottom) flies at a controlled membrane potential of approximately −55 mV; right, combined data from WT, per⁰, per^S, per^L, and pdf⁰¹ flies, not statistically significant between WT and mutant flies by unpaired two-tailed Student’s t test. (B) Left, dual recordings of ipsilateral ITP-LN_d (top) and 5th s-LN_v (bottom) in Clk856-TNT flies; right, cross-correlation analysis (top) and combined data (bottom). (C) Current-voltage correlation relationship of rhythmic EPSCs in ITP-LN_d. Left, representative voltage-clamp recordings at holding voltages indicated; right, plot of peak amplitudes of rhythmic EPSCs against voltages. (D) Top, 25 μM MCA blocked bursts in ITP-LN_d; bottom, combined data. ***P < 0.001 by paired t test. (E) aMe ablation reduces clock neuron bursts. Left, schematic of aMe ablation and dual recordings (top) and combined data (bottom); right, representative dual recordings before (top) and after (bottom) aMe ablation. ***P < 0.001 by paired t test. (F) Schematic of dual recordings in split brain. (G) Representative recordings of ITP-LN_d (top) and 5th s-LN_v (middle) ipsilateral pair in split brains, cross-correlation analysis (bottom). (H) Representative recordings of ITP-LN_d and 5th s-LN_v bilateral pair in split brains (top), cross-correlation analysis (bottom). Combined data are presented as means ± SEM. n.s., not statistically significant, P > 0.05.