Figure 14.

Hypothetical schematic for the transduction of respiratory drive into central respiratory neural output during post-hypoxic periodic breathing. Low respiratory drive (reduced PaCO₂ and relatively higher PaO₂) causes reduced strength of reciprocal inhibition (dashed lines) resulting in mostly tonic inspiratory and expiratory neural output, subsequently producing hypopnea and apnea (A). High respiratory drive (increased PaCO₂ and relatively low PaO₂) causes increased strength of reciprocal inhibition (heavy dark lines) resulting in highly phasic inspiratory and expiratory neural output, subsequently producing hyperpnea (B). Eupneic respiratory drive (“normal” PaCO₂ and PaO₂) causes normal strength of reciprocal inhibition (gray lines) resulting in mostly phasic inspiratory and expiratory neural output, subsequently producing eupnea (C). Note that periods of low and high drive in this Figure correspond to periods of low and high drive in Figure 13.