Regional brain stem activations during capsaicin inhalation using functional magnetic resonance imaging in humans

Abstract

Coughing is an airway protective behavior elicited by airway irritation. Animal studies show that airway sensory information is relayed via vagal sensory fibers to termination sites within dorsal caudal brain stem and thereafter relayed to more rostral sites. Using functional magnetic resonance imaging (fMRI) in humans, we previously reported that inhalation of the tussigenic stimulus capsaicin evokes a perception of airway irritation ("urge to cough") accompanied by activations in a widely distributed brain network including the primary sensorimotor, insular, prefrontal, and posterior parietal cortices. Here we refine our imaging approach to provide a directed survey of brain stem areas act..