Afferent neural pathways mediating cough in animals and humans.

The airways and lungs are densely innervated by sensory nerves, which subserve multiple roles in both the normal physiological control of respiratory functions and in pulmonary defense. These sensory nerves are therefore not homogeneous in nature, but rather have physiological, molecular and anatomical phenotypes that reflect their purpose. All sensory neuron subtypes provide input to the central nervous system and drive reflex changes in respiratory and airway functions. But less appreciated is that ascending projections from these brainstem inputs to higher brain regions can also induce behavioural changes in respiration. In this brief review we provide an overview of the current understanding of airway sensory pathways, with specific reference to those involved in reflex and behavioural cough responses following airways irritation.