Table 2.

Effect of baseline firing rate on the response to hypercapnic acidosis

Baseline Firing Rate	<2 Hz	>2 Hz	All Neurons
High response	392.7±82.1 (n=11)	243±38.2 (n=2)	381.6±55.6*(n=13)
Mean baseline firing rate	1.04±0.17	2.85±0.05	1.32±0.31†
% of neurons	85%	15%
Low response	166±7.9 (n=9)	149.6±12.7 (n=9)	155.9±6.0*(n=18)
Mean baseline firing rate	1.14±0.17	4.04±0.76	2.95±0.49†
% of neurons	50%	50%

Values are means ± SE. The firing rate during hypercapnic acidosis (expressed as a % of control) shown for high-response and low-response neurons, was statistically different

^*(P < 0.001) as were the baseline firing rates

^†(P = 0.006).