Brain activity associated with placebo suppression of the urge-to-cough in humans

Leech, Jennifer, Mazzone, Stuart B. and Farrell, Michael J. (2013) Brain activity associated with placebo suppression of the urge-to-cough in humans. American Journal of Respiratory and Critical Care Medicine, 188 9: 1069-1075. doi:10.1164/rccm.201306-1079OC

Author Leech, Jennifer
Mazzone, Stuart B.
Farrell, Michael J.
Title Brain activity associated with placebo suppression of the urge-to-cough in humans
Journal name American Journal of Respiratory and Critical Care Medicine   Check publisher's open access policy
ISSN 1073-449X
Publication date 2013-11-01
Sub-type Article (original research)
DOI 10.1164/rccm.201306-1079OC
Volume 188
Issue 9
Start page 1069
End page 1075
Total pages 7
Place of publication New York, United States
Publisher American Thoracic Society
Language eng
Subject 2740 Pulmonary and Respiratory Medicine
2706 Critical Care and Intensive Care Medicine
Formatted abstract
Rationale: Antitussive therapies are accompanied by a substantial placebo effect, indicating that inhibitory circuits in the brain have a significant capacity to regulate cough neural processing. However, essentially nothing is known about the identity of these inhibitory circuits or how they reduce coughing. Understanding these processes may help develop more effective antitussive therapies in the future.

Objectives: To identify regional changes in human brain activity related to the urge-to-cough after placebo antitussive administration.

Methods: Seventeen healthy participants undertook functional magnetic resonance imaging while completing a series of inhalations of capsaicin to induce the urge-to-cough. The resultant brain responses associated with capsaicin inhalation without any treatment were compared with those induced by capsaicin after placebo antitussive administration.

Measurements and Main Results: There was a significant decrease in participants’ ratings of urge-to-cough after the placebo antitussive administration. Brain activity associated with capsaicin inhalation was less in the somatosensory, primary motor, insula, and cingulate cortices during placebo antitussive trials compared with no treatment control subjects. By contrast, placebo trials were associated with increased activation in the prefrontal and left parietal cortices.

Conclusions: Placebo-related decreases in urge-to-cough are accompanied by commensurate decreases in several brain regions activated during capsaicin inhalation, suggesting that beliefs about treatment can modify the central processing of inputs arising from the airways. The prefrontal cortex and posterior parietal cortex are likely to play an active role in the modification of airway sensory processing after administration of a placebo.
Keyword Capsaicin
Functional neuroimaging
Magnetic resonance imaging
Placebo effect
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Biomedical Sciences Publications
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