gms | German Medical Science

Neurodegenerative diseases are often associated with olfactory dysfunction and might be the. first clinical manifestation of such a disease. A novel tool for investigation of the human olfactory system is functional magnetic resonance tomography (fMRI) after odorant application. Necessary requirements for this technique are artefact-free application of olfactory stimuli in the scanner environment and the establishment of a useful MRI sequence. Aim of this study was to develop a robust fMRI design for investigations on cerebral olfactory processing. Therefore, a MRI-compliant constant flow olfactometer was developed. Odorant was phenyl ethyl alcohol (PEA). 9 healthy normosmic subjects were measured in a 1.5 Tesla scanner (Siemens Magnetom). 300 whole brain EPI volumes were collected over 11:26 min while 8 seconds lasting PEA stimuli were given. The duration of the resting periods was pseudo-randomized with an average of 33 s. The statistical evaluation of the data was performed by the MATLAB based SPM5 software package. The group analysis showed stable cerebral activations within the insula and the adjacent operculum and orbitofrontal cortex bilaterally. Furthermore, bilateral activations were measured in the cingulum, amygdala and the cerebellum. This activation pattern is in accordance with results described in the literature. Therefore the study design and as well as the developed olfactometer were appropriate to show reliable neuronal activations during odour perception. It can be used in further studies on patients with neurodegenerative diseases and other olfactory disorders.