Abstract (eng)
In the present study, the influence of the monoterpene 1,8-cineole, which was applied transdermally, on the human autonomic nervous system, vigilance, cerebral blood flow and well-being was investigated. 1,8-cineole was expected to have activating properties.
Each of the 18 right-handed subjects got the placebo as well as the odorant during the 90-minute testing phase, which was divided into three sessions. During the first session the subjects had to perform a 5-minute visual vigilance task followed by a 10-minute resting state. The placebo was applied right before the second session, which was also divided into a testing phase and a resting state. 1,8-cineole was applied before the third session, in which the task was repeated four times.
The cerebral blood flow was registered using fMRI, whereas vigilance was tested with a 1-back-task. The heart and the respiratory state were monitored during the whole experiment and the subjects were asked to rate their well-being on visual analog scales.
The fMRI-data were analysed using SPM, the other data were evaluated by means of univariate 2-way analysis of variance.
The fMRI-data showed an increase of the cerebral blood flow during the third session, in which the fragrance was applied, in brain areas, which could be attached to attention, e.g. präcuneus and gyrus präcentralis, as well as in regions that could be attached to olfaction, e.g. the Brodmann area 47. This result wasn’t expected, because the subjects received odourless air via breathing masks.
The findings of the vigilance task showed an activating effect of 1,8-cineole. According to that an increase of hits and response time after the fragrance was applied could be observed. The decrease of the heart and the respiratory rate, whereas the vigilance was upgraded, suggested that 1,8-cineole has an activating effect. In conflict with those findings the subjects felt tired and spiritless at the end of the investigation. This could be a result of the long test duration.