Fig. 4.

Suppression of electrical coupling during hypercapnia. A. A sharp central peak was seen in a pair of CO₂-stimulated units. The spike trains of these units occurred almost always simultaneously with the background counts barely seen in regular scale (A₁). Seen in log scale (A₂), the background counts were not symmetric (coupling efficiency = 0.99). B₁, B₂. The coupling between these units was greatly diminished during high CO₂ exposure (coupling efficiency = 0.10). C, D. The spike morphology and interspike histograms show single unit recordings with action potential duration > 1ms (C₁, D₁) for both units. E, F. Statistical analysis show that the electrical coupling is suppressed in CO₂-stimulated units (P=0.006, n=4) but not in CO₂-unresponsive units (P=0.21, n=12). Data are represented as mean ± S.D.