KNDy neurons exhibit spontaneous episodic activity that is regulated by steroids. (A–D) Top: representative extracellular recordings of KNDy neurons from (A) intact (I), (B) castrated (C), (C) castrated + estradiol (C+E), and (D) castrated + DHT (C+DHT) male mice during a nadir and a peak; bottom: pattern of activity plotted as number of events per 2 minutes. Note vertical axis scale change for top panel in D, as events were larger-amplitude in this recording, which was selected for the representative nature of event pattern. Amplitude is not a meaningful measure of biological changes with this type of recording as it depends on several technical, rather than biological, variables. Gray boxes show peaks detected by a version of Cluster running in IgorPro software. Dashed lines on the bottom panels indicate the timing of the traces in the top panel of each figure. (E, F, G) Individual values and mean ± SEM for (E) firing rate, (F) peaks/h, and (G) nadir duration. *P < 0.05 vs intact group, Kruskal-Wallis/Dunn test.