Fig. 3

Firing patterns of the terminal nerve GnRH neurons in juvenile medaka (a) A scheme of post-hatching development of medaka. (b–e) Representative firing patterns in medaka. The firing patterns in B and C were recorded from medaka 4 weeks after fertilization, and that in D from medaka 7 weeks after fertilization. The time and current scales shown in the upper right corner of B apply to B–D. (e) Categorized firing patterns of TN-GnRH3 neurons in one typical fish for each stage. We used the average value for each pattern. The classification of the firing pattern is as follows: burst firing, consecutive spikes more than three at > 3 Hz (firing frequency in adult medaka is usually lower than 2 Hz) and interburst interval longer than 1 second (longer than that of typical TN-GnRH3 neurons in adults); regular firing, coefficient of variation of the interburst interval < 0.65 (the coefficient of variation is defined as the ratio of the standard deviation to the mean interburst interval); irregular firing, others. Juvenile: 3 weeks after fertilization, nine fish; 4 weeks, nine fish; 5 weeks, seven fish; 6 weeks, eight fish;7 weeks, eight fish. Adult: > 12.5 weeks, four fish. These figures were modified from Umatani and Oka, 2018 [27]