The aim of this article is to investigate the cortical metabolic
arrangements in olfactory processing by using 18F fluorodeoxyglucose
(FDG) positron emission tomography/computed tomography.
Twenty-six normosmic individuals (14 women and 12 men; mean
age 46.710 years) were exposed to a neutral olfactory condition
(NC) and, after 1 month, to a pure olfactory condition (OC) in a
relatively ecological environment, that is, outside the scanner. All
the subjects were injected with 185-210 megabecquerel of 18F FDG
during both stimulations. Statistical parametric mapping version 2
was used in order to assess differences between NC and OC.
As a result, we found a significant higher glucose consumption
during OC in the cuneus, lingual, and parahippocampal gyri, mainly
in the left hemisphere. During NC, our results show a relative higher
glucose metabolism in the left superior, inferior, middle, medial
frontal, and orbital gyri as well as in the anterior cingulate cortex.
The present investigation, performed with a widely available
functional imaging clinical tool, may help to better understand the
neural responses associated to olfactory processing in healthy individuals
and in patients with olfactory disorders by acquiring data in an
ecologic, noise-free, and resting condition in which possible cerebral
activations related to unwanted attentional processes might be avoided.
