Figure 1.

Nonarousals (white bars), sub-cortical activations (striped bars), and cortical arousals (solid bars) of smoke-exposed infants in response to air-jet stimulation at 2-4weeks, 2-3 months, and 5-6 months, during quiet sleep (QS) and active sleep (AS) in both prone (P) and supine (S) sleeping positions. Data are expressed as proportions of total air-jet tests, with total stimuli numbers shown within the histograms. ***P < 0.001 between prone and supine positions (χ² analysis).