Egg-laying correlates with repolarization in VC Ca2+ spikes. A) Representative Ca2+ spikes in HSN and VC cells during egg-laying. The inset defines the terms used: a: spike duration is time from the start of depolarization until the peak of the spike. B): egg-laying timing is the time from the start of depolarization until the egg-laying event. c: spike ratio change is the background normalized cameleon ratio signal difference between the start of depolarization and the peak of the spike. d: the depolarization slope is c over a. B) and C) Correlation for various pairs of parameters in HSN and VC spikes, respectively. The Pearson correlation coefficient (r) and corresponding p-value are indicated. A strong statistically significant correlation is only found between egg-laying timings and VC spike timings.