Florey Neurosciences Institutes, University of Melbourne, Vic 3010, Australia.
Neuroimage. 2012 Jul 16;61(4):1324-35. doi: 10.1016/j.neuroimage.2012.03.030. Epub 2012 Mar 16.
The perception of airways irritation is represented in a distributed brain network. However, the functional roles of sub-regions of this network are yet to be determined. The aim of this study was to measure brain activation in healthy participants as they inhaled two doses of capsaicin to identify dose-dependent and dose-independent responses. Blood oxygen level-dependent functional magnetic resonance imaging (fMRI) measures of brain responses during inhalation of saline, and a low and high dose of capsaicin were made from 16 healthy participants. Subjective ratings of the urge-to-cough were also made during capsaicin challenges. The majority of brain regions that were activated during capsaicin inhalation, including insula and mid cingulate cortex, showed graduated responses to the two doses of capsaicin. Prefrontal and parietal regions had dose-independent activation, whereas premotor regions and the cerebellum activated exclusively at the high dose of capsaicin. Activation in the somatosensory and mid-cingulate cortices correlated with ratings of urge-to-cough. In the brainstem, capsaicin produced dose-dependent activations in respiratory-related regions of the dorsal pons and lateral medulla. These data show dissociable response patterns to capsaicin inhalation that may represent different regional processes involved in monitoring and assessing stimulus intensity, determining the spatial localization of the stimulus and suppressing motor responses.
气道刺激的感知是由一个分布式的大脑网络来表示的。然而，这个网络的子区域的功能作用仍有待确定。本研究的目的是测量健康参与者在吸入两种剂量辣椒素时的大脑激活情况，以确定剂量依赖性和剂量非依赖性反应。从 16 名健康参与者中采集了吸入盐水、低剂量和高剂量辣椒素时血氧水平依赖功能磁共振成像 (fMRI) 测量的大脑反应数据，并在辣椒素挑战期间对咳嗽冲动的主观评分进行了测量。在吸入辣椒素时被激活的大多数大脑区域，包括脑岛和中扣带皮层，对两种剂量的辣椒素都表现出逐渐增加的反应。前额叶和顶叶区域有剂量非依赖性的激活，而运动前区域和小脑则仅在高剂量的辣椒素时被激活。躯体感觉和中扣带皮层的激活与咳嗽冲动的评分相关。在脑干中，辣椒素在延髓背侧和外侧的呼吸相关区域产生剂量依赖性的激活。这些数据显示出对辣椒素吸入的可分离的反应模式，这可能代表了不同的区域过程，涉及到监测和评估刺激强度、确定刺激的空间定位和抑制运动反应。
