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Dissociation of the neural correlates coding stimulus intensity and perception of capsaicin urge‐to‐cough in humans
Author(s) -
Mazzone Stuart,
Cole Leonie,
Farrell Michael
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1077.14
Subject(s) - capsaicin , insula , stimulus (psychology) , sensory system , neuroscience , psychology , midbrain , audiology , anesthesia , medicine , central nervous system , cognitive psychology , receptor
Inhalations of capsaicin are associated with increasing ratings of urge‐to‐cough. We hypothesised that brain regions involved in urge‐to‐cough intensity discrimination would show increased activation at higher compared to lower capsaicin concentrations. Functional brain images were acquired with a Siemens 3T scanner from healthy subjects (n=16) during repeated 18s blocks of inhalation via nebuliser of saline, a low concentration or a high concentration of capsaicin. General linear modelling was used to identify variance in signals associated with inhalation events, and contrasts were generated to identify capsaicin intensity‐dependent activation. Capsaicin challenges produced activations in a widely distributed brain network which included sensory, motor, midbrain, limbic and cerebellar regions. Regional brain activations were classified as (a) stimulus intensity dependent (anterior insula, anterior midcingulate and primary motor cortices), (b) all or nothing (prefrontal, posterior parietal cortices), or (c) dependent upon the perceived level of urge‐to‐cough experienced (primary sensory cortex). These data suggest that the actual intensity and the subjective experience are differentially represented in the brain urge‐to‐cough network. Furthermore, posterior parietal and prefrontal regions likely play a role in spatial discrimination rather than intensity detection.