Fig. 3

Effects of anoxia. A–D Electromyograms obtained from the diaphragm (Dia) and abdominal muscles (Abd). Numbers 1–5 in A indicate the stages following anoxic stimulation (100% N₂) referred to in the text. In B and C, the portions of recording A above the horizontal bars marked B and C are shown on an expanded time scale. D The portions of recording A indicated by the letters a–f are shown on an expanded time scale. After the inspired gas was switched to 100% N₂, the inspiratory bursts in the diaphragm were depressed transiently and then increased gradually (C). The first inspiratory activity that occurred after the transient disappearance is indicated by a black circle, and this time was defined as the onset of gasping. The expiratory activity disappeared before terminal apnea (e and f in panel D)