Brainstem processing of cough sensory inputs in chronic cough hypersensitivity

Area of Science:

• Neuroscience
• Respiratory Medicine

Background:

• Chronic cough is a common, challenging condition linked to cough hypersensitivity.
• Cough hypersensitivity involves exaggerated responses to sensory stimuli, possibly due to altered airway nerve activity and brainstem processing.

Purpose of the Study:

• To investigate brainstem activation patterns in chronic cough patients using functional magnetic resonance imaging (fMRI).
• To compare neural responses to inhaled capsaicin and adenosine triphosphate (ATP) between chronic cough patients and healthy controls.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to assess brainstem responses.
• Participants inhaled capsaicin and ATP, with psychophysical testing to match urge-to-cough sensations between chronic cough patients and controls.

Main Results:

• Chronic cough patients showed increased sensitivity to inhaled capsaicin and ATP.
• When urge-to-cough was matched, chronic cough patients exhibited reduced activation in medullary regions but increased activation in a midbrain region.
• Cortical activation patterns related to cough sensation did not differ between groups.

Conclusions:

• Cough hypersensitivity in some chronic cough patients may stem from brain circuits above the medulla.
• Altered midbrain activity could amplify sensory signals or impair central inhibitory control in chronic cough.