Sensations and regional brain responses evoked by tussive stimulation of the airways

Abstract

Stimuli that evoke cough in humans also elicit a sensation described as the urge-to-cough. This sensation is perceived at levels of stimulation below the threshold for coughing and increases in intensity in response to higher levels of stimulation. Cough in humans can be consciously modified in intensity or suppressed altogether, and the urge-to-cough is likely to contribute to discretionary responses to tussive stimulation. Converging evidence from animal and human experiments have identified a widely distributed network of brain regions that are implicated in the representation of urge-to-cough and the control of coughing. This network incorporates regions that show responses associated with urge-to-cough ratings, such as limbic and somatosensory cortices, as well as paralimbic and premotor regions implicated in response inhibition that activate in association with efforts to suppress cough. The urge-to-cough can be influenced by psychological factors and preliminary findings suggest that these effects could be mediated by top-down influences. There is considerable impetus to understand circuits involved in the modulation of urge-to-cough because it may be possible to antagonise the troubling sensation while preserving the critical cough reflex.