Boyle Julie A, Djordjevic Jelena, Olsson Mats J, Lundström Johan N, Jones-Gotman Marilyn
Department of Psychology, McGill University, H3A 2T5 Montreal, QC, Canada.
Cereb Cortex. 2009 Jan;19(1):66-71. doi: 10.1093/cercor/bhn058. Epub 2008 Apr 28.
Single odors are processed differently from odor mixtures in the cortex of rodents. We investigated whether single and binary odor mixtures activate different regions also in the human brain. We analyzed data from positron emission tomography scans using pyridine, citral, and 5 mixtures of pyridine and citral in proportions varying from 10/90 to 90/10, with 50/50 being the most impure. Comparing mixtures with single odorants gave activation in the left cingulate and right parietal and superior frontal cortices and bilateral activation in the anterior and lateral orbitofrontal cortices. We also found that brain activity in the lateral orbitofrontal cortex (OFC) increased with odorant impurity, whereas the anterior OFC was activated for binary odor mixtures and deactivated for single components. We conclude that binary odor mixtures and their individual components are processed differently by the human brain. The lateral portion of the OFC responds to mixture impurity in a graded fashion, whereas the anterior portion acts like an on-off detector of odor mixtures.
在啮齿动物的大脑皮层中，单一气味和混合气味的处理方式不同。我们研究了单一气味和二元气味混合物在人类大脑中是否也会激活不同区域。我们分析了正电子发射断层扫描的数据，使用了吡啶、柠檬醛以及吡啶和柠檬醛的5种混合物，其比例从10/90到90/10不等，其中50/50的混合物最不纯。将混合物与单一气味剂进行比较，结果显示左扣带回、右顶叶和额上叶皮质出现激活，并且在前眶额皮质和外侧眶额皮质出现双侧激活。我们还发现，外侧眶额皮质（OFC）的大脑活动随气味剂不纯程度增加，而前眶额皮质在二元气味混合物刺激下被激活，在单一成分刺激下则失活。我们得出结论，人类大脑对二元气味混合物及其单个成分的处理方式不同。外侧眶额皮质以分级方式对混合物不纯做出反应，而前眶额皮质则像气味混合物的开关探测器。
