Figure 7. Main pathways underlying subconscious control of respiration Schematic drawing representing the brain areas most involved in subconscious control of respiration and the main pathways connecting them.

Fat lines indicate relatively strong connections and thin lines moderately strong ones. Sparse connections are not included in this scheme. When an area is marked with ‘CO₂’ it contains central chemoreceptor properties, while the carotid bodies sense blood levels of CO₂ and of O₂. The central pattern generators are indicated with a sine wave. BNST = bed nucleus of the stria terminalis; cVRG = caudal ventral respiratory group; LPBN = lateral parabrachial nucleus; MPBN = medial parabrachial nucleus; NTS = nucleus tractus solitarii; PiCo = postinspiratory complex; PPTg = peripeduncular tegmental nucleus; rVRG = rostral ventral respiratory group. See also Supplementary file 1.