Fig. 4.
Illustrative cardiorespiratory traces in a Phox2b27Alacki/+ mutant mouse at postnatal day (P) 8 exposed to ketamine. (A) The end of the series of gasps gradually diminishing in size followed by terminal apnea. (B) Cardiac activity outlasted the terminal apnea, showing that death was caused by respiratory arrest. P14 to P16 mice presented similar patterns of lethal respiratory arrests. ECG, electrocardiography.