Table 1.

Characteristics of central respiratory output in nt-4 knockout mice (nt-4^−/−) compared with wild-type mice at P1.5

Genotype	n	Mean frequency (bursts min−1)	Respiratory cycle length variability †	Burst duration (ms)
Wild-type	4	4.00 ± 0.26	1.02 ± 0.13	456 ± 88.0
nt-4−/−	6	3.69 ± 0.64 ‡	1.24 ± 0.16 ‡	432 ± 60.0 ‡

^†Respiratory cycle length variability is expressed as a coefficient of variation (s.d./mean); mean number of measured cycles was not significantly different between groups (wild-type, 56.8 ± 8.7; nt-4^−/−, 74.0 ± 18.1).

^‡Not significantly different from wild-type.