title: [Functional magnetic resonance imaging of brain activation in early period after olfactory adaptation].
abstract: OBJECTIVE
  To explore the brain activation before and in early period after olfactory adaptation using functional magnetic resonance imaging, and discuss the mechanisms of olfactory adaptation.
  
  
  METHODS
  Ten right-handed, normosmic subjects underwent 2 times of olfactory stimulation tasks with the interval of 20 minutes. The odorant used was isovaleric acid. The fMRI data was processed by the SPM5 software. Rating odor intensity and valence using visual analogue scale (VAS), and the results of 2 tasks were statistically analyzed.
  
  
  RESULTS
  There was no significant difference between 2 tasks on both intensity and hedonicity scores. In task 1, the brain activation in bilateral cerebellum, frontal (including orbitofrontal gyrus), insula, thalamus, cingulate gyrus, putamen, amygdala, piriform cortex, the left inferior parietal lobule, precentral gyrus, right hippocampus, pallidum, middle temporal gyrus, supramarginal gyrus. In task 2, only the right middle frontal gyrus activated, and the voxels decreased significantly. Paired t-test results showed that: (task1-task2) activated regions in left precentral gyrus, frontal lobe (including the orbitofrontal gyrus), insula, right superior temporal gyrus, cerebellum; (task2-task1) activation in the left inferior parietal lobule and right lingual gyrus.
  
  
  CONCLUSIONS
  The sensitivity of brain activation is still at a low level, when subjects had recovered from adaptation in subjective olfactory perception. Underwent repeated olfactory stimulation, second olfactory cortex plays less role on olfactory perception and advanced processing.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Suegery, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.forename: Yong-xiang
authors.initials: YX
authors.lastname: Wei
authors.forename: Hua
authors.initials: H
authors.lastname: Gu
authors.forename: Kun-yan
authors.initials: KY
authors.lastname: Li
authors.forename: Jin-feng
authors.initials: JF
authors.lastname: Zhang
authors.forename: Li-fang
authors.initials: LF
authors.lastname: Si
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D055696:Olfactory Perception / Q000502:physiology*