Figure 2.

Respiratory frequency is independent of acute CO₂ presentation. A, Example respiratory traces from an anesthetized mouse during presentation with “blank” (N₂), 50% CO₂, and 100% CO₂ stimuli (all at 1 L/min flow rate). B, Mean respiratory frequency 2 s prior (baseline, −2 to 0 s) and during (0–2 s) presentation with either 50% or 100% CO₂. n = 7 mice, 8–12 trials/mouse.