The effects of lavender oil inhalation on emotional states, autonomic nervous system, and brain electrical activity.

OBJECTIVE: Investigate the effects of lavender oil on the central nervous system, autonomic nervous system, and mood responses in humans after inhalation. MATERIAL AND METHOD: Twenty healthy volunteers participated in the experiments. The present study assessed autonomic parameters such as blood pressure, heart rate, respiratory rate, and skin temperature to determine the arousal level of the autonomic nervous system. In addition, subjects were asked to estimate their mood responses such as feeling pleasant or unpleasant, uncomfortable, sensuality, relaxation, or refreshing in order to assess subjective behavioral arousal. Finally, electroencephalogram (EEG) was recorded from 31 electrodes on the scalp according to the international 10 to 20 system, and EEG power spectra were calculated by Fast Fourier Transform (FFT). Data was analyzed by comparing the effects of lavender oil on physiological and mood states with sweet almond oil. These assessments were measured before and after using paired t-test statistical procedure. RESULTS: The results revealed that lavender oil caused significant decreases of blood pressure, heart rate, and skin temperature, which indicated a decrease of autonomic arousal. In terms of mood responses, the subjects in the lavender oil group categorized themselves as more active, fresher relaxed than subjects just inhaling base oil. Compared with base oil, lavender oil increased the power of theta (4-8 Hz) and alpha (8-13 Hz) brain activities. The topographic map showed obviously more scattering power in alpha range waves particularly in bilateral temporal and central area. CONCLUSION: The findings provided evidence the relaxing effect of inhaling lavender oil.

Neural activity in readiness for incidental and explicitly timed actions.

Voluntary, self-initiated actions are preceded by slowly increasing neural activity in pre-motor regions of the brain, beginning up to 2s before the onset of muscle movement. This activity is commonly seen in the scalp-recorded readiness potential, and is an index of movement preparation involving both motor programming and non-motor or cognitive processes such as attention. The specific contribution of cognitive processes, thought to occur during the earliest stage of planning, remains somewhat unclear. We suggest that attention to the timing of movement is a key voluntary process contributing to early-stage cortical activity. As a novel approach to examining this, we recorded EEG throughout a time reproduction task in which participants replicated the interval between two tones with two button-press actions. The first action, i.e. the beginning of the reproduced interval, was somewhat incidental to the task of time reproduction and required minimal attention to the time of initiation, while the second action required explicit attention to the time of initiation. Pre-movement neural activity preceding the first, relatively unattended movement was greatly reduced in amplitude and almost absent in the early stage, in contrast with readiness potentials typically seen prior to voluntary movement. Neural activity preceding explicitly timed movements was significantly larger, with effects emerging in the early component of pre-movement activity over frontal and right frontal scalp regions. We propose that attention to movement timing, i.e. the process of orienting attention in time towards the moment of movement initiation, is a key component of voluntary action preparation that is reflected in the early-stage neural activity we typically see prior to voluntary movement.