ODORANT-INDUCED AND SNIFF-INDUCED ACTIVATION IN THE CEREBELLUM OF THEHUMAN

Functional magnetic resonance imaging was used to test whether odorant s induce activation in the cerebellum of the human. The odorants vanil lin and propionic acid both induced significant activation, primarily in the posterior lateral hemispheres. Activation was concentration-dep endent, greater after stimulation with higher concentration odorants. By contrast, the action of sniffing nonodorized air induced significan t activation in the anterior cerebellum, primarily in the central lobu le. These findings demonstrate that the cerebellum plays a role in hum an olfaction. A hypothesis is proposed whereby the cerebellum maintain s a feedback mechanism that regulates sniff volume in relation to odor concentration.