Figure 2.

Spontaneous activity without stimulus presentation during 3% and 6% CO₂ administration. (A) Gamma band decreased to 97.5 ± 4% and 84.7 ± 4%, beta band to 97.5 ± 5% and 89.9 ± 8% and MUA to 96.3 ± 6% and 85.3 ± 5% for the 2 levels of CO₂ inhalation (n = 9). The change in spontaneous activity in these 3 bands is highly significant for 6% CO₂ (P < 0.0005). For 3% CO₂, a trend toward neuronal activity reduction is visible (P ∼ 0.1). (B) Theta and alpha bands do not change under mild and moderate hypercapnia (P between 0.2 and 0.6). *Depicts significant changes.