Smell detection could be traced in fNIR signals recorded from the forehead

摘要

Objective assessment of olfactory function has diagnostic and legal value. We have designed an odor detection task inwhich the subject reported the conscious sensing of an odorant via a button press while the hemodynamic activity fromthe forehead was monitored using a 4-channel fNIRS system. The task consisted of intermingled odor and non-odortrials. We recorded from 17 subjects and each of them underwent 60 trials. The time domain analysis of the raw datashowed that the hemodynamic activity was statistically different between the odor and non-odor trials especially foroxyhemoglobin in far channels. In order to single out the odor-induced hemodynamic response from that of motor activity,finger tapping was considered as a control condition for odor detection. Pairwise correlation indicated that motor activityhad a short lasting influence on hemodynamic response while the hemodynamic response to different odors werehighly correlated over time. In conclusion, we believe that fNIRS monitoring of hemodynamic response could be potentiallyused for objective assessment of odor detection in cases that subjective report is unreliable.