AUGMENTING EXPIRATORY NEURONAL-ACTIVITY IN SLEEP AND WAKEFULNESS AND IN RELATION TO DURATION OF EXPIRATION

Augmenting expiratory cells (n = 23) were recorded in the rostral medu lla of five cats in sleep and wakefulness. The objective was to determ ine the relationship of their activity to the duration of expiration ( TE) and, particularly, to TE in rapid-eye-movement (REM) sleep, when e xpirations are short and may even cause fractionated breathing. Correl ation analysis (Kendall's tau) showed no consistent relationship in an y state between the breath-by-breath mean activity of augmenting expir atory cells and TE. This result contradicts predications of an inverse relationship between augmenting expiratory activity and TE. Some cell s (11 of 23) were more active in REM than in non-REM sleep and were ac tive during fractionated breathing. This suggests that fractionated br eathing in REM sleep is caused by short expiratory phases and not by i ntermittent inhibition of an ongoing inspiration.