Organization of central pathways mediating the Hering-Breuer reflex and carotid chemoreflex.

The above modeling results suggest several general and special principles of neural organization that may underlie the central mediation of HBR and CCR: 1. The immediate HBR effects on TE and (via mutual inhibition) on TI appear to be mediated by an identified paucisynaptic central pathway. The immediate CCR effects on TE, TI and Phr may be mediated by fast secondary integrator (or low-pass filtering) pathways instead of primary reflex pathways. Additional secondary differentiator (or high-pass filtering) pathways via the rostrolateral/ventrolateral pons may underlie the desensitization of HBR/CCR response in TE. Additional secondary integrator pathways (loci unclear) may underlie the sensitization of CCR response in TI and Phr. These parallel CCR integrator-differentiator pathways appear to be individually gated to a specific respiratory phase by corresponding E or I phase filters. NTS synaptic depression may underlie response habituation of HBR and CCR.