Functional neuroimaging of the olfactory system in humans

Positron emission tomography (PET) and functional magnetic resonance imagin g (fMRI) have begun to provide unique information regarding the neural unde rpinnings of olfactory functioning in humans. We review the relative streng ths and weaknesses of PET and fMRI techniques for studying olfaction. We th en review PET and fMRI studies relating to the olfactory functions of the p yriform cortex, orbitofrontal cortex, amygdala and the entorhinal/hippocamp al region. A pixelwise correlational analysis of PET data is also presented in order to clarify the relationship between blood flow in the medial temp oral lobes and psychoperceptual variables. (C) 2000 Elsevier Science B.V. A ll rights reserved.