Fig. 1.

Long-lasting inactivity-induced phrenic motor facilitation (iPMF) is pattern dependent in Charles River Sprague-Dawley rats. A. representative compressed phrenic (Ph) neurograms depicting integrated nerve burst amplitude before (baseline), during, and for 60 min following either brief intermittent, brief massed, or prolonged neural apnea, or an equivalent duration in time controls (top to bottom, respectively). B: mean changes in phrenic burst amplitude (% change from baseline) 5, 15, 30, and 60 min following brief intermittent (●), brief massed (■), prolonged (▲), or no neural apnea (time controls; ▼). C: Average phrenic burst amplitude responses to hypercapnic challenge 60 min after neural apnea. Shaded bar indicates a significant long-lasting iPMF was expressed. D: linear regression comparing the magnitude of iPMF 60 min post neural apnea to the maximum phrenic amplitude elicited during a subsequent hypercapnic challenge, indicating iPMF is associated with a proportional increase in respiration-related phrenic dynamic range. *Significantly different from time control. #Significantly different from brief massed neural apnea. ϕSignificantly different from prolonged neural apnea; P < 0.05.