Bensafi M, Iannilli E, Gerber J, Hummel T
Université Claude Bernard, Lyon, Laboratoire de Neurosciences Sensorielles, Comportement, Cognition, UMR 5020, Institut Fédératif des Neurosciences de Lyon, IFR19, CNRS, Lyon, France.
Neuroscience. 2008 Jun 23;154(2):832-8. doi: 10.1016/j.neuroscience.2008.03.079. Epub 2008 Apr 11.
Nasal chemical sensations are mediated principally by the olfactory and the trigeminal systems. Over the last few years brain structures involved in processing of trigeminal stimuli have been more and more documented. However, the exact role of individual regions in stimulus intensity processing is unclear. The present study set out to examine the neural network involved in encoding stimulus intensity in the trigeminal system and the olfactory system of humans. Participants were presented with two concentrations of relatively specific trigeminal stimuli (CO2) and olfactory (H2S), respectively. Responses were assessed by functional magnetic resonance imaging (fMRI). Whereas brain responses to stimulus intensity in the olfactory modality involved a wide neural network including cerebellum, entorhinal cortex, visual areas, and frontal regions, contrasting high and low CO2 concentrations revealed activation in a less complex network including various sub-regions of the cingulate cortex. Taken together, these results suggest separate but overlapping neural networks involved in encoding stimulus intensity in the two chemosensory systems.
鼻腔化学感觉主要由嗅觉和三叉神经系统介导。在过去几年中，参与处理三叉神经刺激的脑结构越来越多地被记录下来。然而，各个区域在刺激强度处理中的确切作用尚不清楚。本研究旨在研究人类三叉神经系统和嗅觉系统中参与编码刺激强度的神经网络。分别向参与者呈现两种浓度的相对特定的三叉神经刺激（二氧化碳）和嗅觉刺激（硫化氢）。通过功能磁共振成像（fMRI）评估反应。虽然嗅觉模式下对刺激强度的脑反应涉及一个广泛的神经网络，包括小脑、内嗅皮质、视觉区域和额叶区域，但对比高浓度和低浓度二氧化碳时，发现激活的是一个不太复杂的网络，包括扣带回皮质的各个亚区域。综上所述，这些结果表明，在两个化学感觉系统中，参与编码刺激强度的神经网络是分开但重叠的。
