Figure 6.

Figure 6.

IPSCs mature from arrhythmic at 3 dpf to rhythmic with a frequency close to that of tail beats at 5 dpf during swimming episodes. A, Typical voltage-clamp recordings of MNs during swimming activity at resting (−65 mV) and cation reversal potentials (0 mV) for 3-dpf (Ai, Aii), 4-dpf (Aiii, Aiv), and 5-dpf (Av, Avi) fish. B, Short-time Fourier transform (STFT) of a 30-s-long recording of spinal cord activity under control and strychnine conditions at 3 dpf (Bi, Bii) and 5 dpf (Biii, Biv). White dotted lines mark the 20- to 40-Hz frequency range. We can observe local maxima in the 20- to 40-Hz range for both 5-dpf plots but not for the 0-mV 3-dpf plot. C, Results from Peak_20–40 detection algorithm in the 25- to 50-ms time delay range for autocorrelation functions of each traces at 3, 4, and 5 dpf at −65 mV (blue) and 0 mV (red) holding potentials. N = 10 episodes per sMN in five sMN at 3 dpf, in four sMN at 4 dpf, and four sMN at 5 dpf. Error bars display SEM. Two-tailed paired Student’s t test (3 dpf −65 to 0 mV, p = 0.0139; 4 dpf −65 to 0 mV, p = 0.3910; 5 dpf −65 to 0 mV, p = 0.1942); *p < 0.0166, indicating significance with Bonferroni’s multiple-comparisons correction.