Objectives: To clarify the effect of olfactory stimulation with perilla essential oil on human prefrontal cortex activity using near-infrared time-resolved spectroscopy.
Design: Single-center prospective study.
Methods: Nineteen female university students (mean age, 21.6 ± 1.5 years) participated in the study. Perilla essential oil was used as an olfactory stimulant and air as a control. Oxyhemoglobin concentrations in the prefrontal cortex were measured by using near-infrared time-resolved spectroscopy when the participants were presented with the stimulant or control. Emotional effects were subjectively evaluated by using a modified semantic differential method.
Results: Olfactory stimulation with the perilla essential oil significantly reduced the oxyhemoglobin concentration in the prefrontal cortex. No significant differences in the feelings of comfort or relaxation, which strongly reflect human mental status, were observed between the perilla essential oil and control periods.
Conclusions: Olfactory stimulation with perilla essential oil reduced prefrontal cortex activity, thereby inducing physiologic relaxation.