Cortical and subcortical central neural pathways in respiratory sensations.

Respiratory sensations motivate humans to behaviorally modulate their breathing and are the sensory urge component of the respiratory motivation-to-action neural system. Human and animal studies have provided evidence for the neural substrate for afferents in the respiratory tract and muscles to project to the cerebral cortex. Respiratory afferents continually transduce breathing pattern into a sensory neural code. This neural code is transmitted to a subcortical gating area. Respiratory sensory information is then transmitted by respiratory modality specific convergent and divergent subcortical pathways to the cerebral cortex. There are two primary cortical pathways: (1) the discriminative pathway related to respiratory proprioception and (2) the affective pathway related to the qualitative assessment of breathing. Respiratory sensory information is processed by the discriminatory somatosensory-motor cortex and the affective mesocortex resulting in conscious awareness of breathing that can lead to distressing respiratory sensations. The significance of respiratory sensory information processing is the fundamental interoceptive perception of ventilatory status.