Cerebellar Gray Matter and Olfactory Performance.

The role of the cerebellum in the chemical senses is still poorly understood. This voxel-based morphometry (VBM) study investigated associations between gray matter volume (GMV) in subregions of the cerebellum and olfactory performance. VBM data from 48 men were analyzed. The participants were tested with a standardized olfactory test that measured olfactory threshold, discrimination, and identification ability. The investigated sample covered a wide range of olfactory performance, including individuals with a reduced sense of smell (anosmia and hyposmia) and normosmia. The computed regression analyses revealed a positive association between olfactory identification performance and GMV in lobule VI. This cerebellar subregion is involved in higher-order cognitive functions (language and memory), which are necessary prerequisites for correct odor labeling. Odor detection and discrimination were unrelated to cerebellar GMV.