We recorded EEG in adult volunteers in the course of perception of smells of plant essential oils under conditions of directed attention. It was found that perception of olfactory information, even in the case of mild intensity of the smells inducing no aversive effects, correlates with noticeable changes in the EEG characteristics mostly typical of the reaction of nonspecific EEG activation induced by sensory stimulation and manifested in a decrease in the spectral power, SP, of low-frequency EEG components (6-10 Hz)). In addition, the SP of relatively high-frequency EEG components (11-25 Hz) increased; this effect was most pronounced in the occipital regions of the neocortex. Perception of the smells of essential oils was also accompanied by increases in the coherence of EEG oscillations, most intense in the β2 range (20-25 Hz). Such modifications were maximum in the left temporal/parietal region; this is interpreted as an indication of the special role of these cortical areas in the processes of interaction between the neocortical part of the olfactory analyzer and the respective structures of other analyzer systems. It is hypothesized that such interaction is necessary for the formation of a semantic image of the analyzed stimuli.

We studied changes in human EEGs related to presentation of olfactory stimuli (smells of essential oils) and dependence of such rearrangements on the level of extroversion/introversion typical of the tested subject. It was shown that this feature of personality noticeably influences the pattern of odorant-induced changes in EEG. Persons with a predominance of introversion were characterized by higher levels of nonspecific activation of the brain related to perception of olfactory stimuli, which was manifested in a decrease in the power of lowfrequency EEG components in the parietal, occipital, and temporal cerebral cortices. The pattern of the rise in coherence level of high-frequency spectrum range oscillations directed toward caudal leads is considered a manifestation of intensification of the intrinsic associative processes. In individuals with a predominance of extroversion, we observed, on the whole, smaller levels of nonspecific cerebral activation upon the action of olfactory stimulation. The fronto-parietal pattern of spatial EEG synchronization is indicative of the development of sensory-analytical processes related to perception of external information. In general, our data agree with the interpretation of such a psychological parameter as extroversion/introversion.

No abstract

It is known that physiological characteristics of an individual arecorrelated with the formation of a person's emotional background when perceiving external sensory stimuli, as indicated by the close relationshipbetween olfactory and emotiogenicbrain structures. Individual ranking of pleasant and unpleasant odors can be described interms of typological and personality traits, and is associated with persistentpsychological characteristics. We aimed to determine the relationship between preference of essential oil andpsychological individual characteristics. 110healthy volunteers (women and men) -students aged 18 to 23 years with no documented manifestations of rhinalpathologies participated in this study. We used the following tests: ‘Personality differential’, ‘Personality and typological inventory’ by L.N. Sobchik, WAM (Wellbeing, Activity, Mood), and State Anxiety Inventory byC. Spielberger, Y. Hanin. We selected essential oils ofmint, lavender, lemon, rose, common wormwood, pine, ylang-ylang, and sandalwood. Rejection of certain essential oils may be caused by ostensibly real negative personal characteristics, which s/he seeksto get rid of. Amongthose with normal level of anxiety the description of the most pleasant odorwas similar to the description of the real ego. Among those with an anxious accentuation and anxious psychopathythe description of the most pleasant odor and the dynamic ego were similar. Thus, a person consciously hands over a choiceof odor to the personalcharacteristics s/he believes canenhance or rouse positive feelings: subjectively pleasantodors reduced the level of StateAnxiety, improved Wellbeing and Mood, and increased activity.