title: Effects of olfactory stimulation with rose and orange oil on prefrontal cortex activity.
abstract: OBJECTIVE
  People have been aware of essential oils, which are derived from plants, for a long time. Recently, we have become interested in physiological and subjective effects of daily exposure to essential oils. The primary aim of the present study was to clarify effects of olfactory stimulation with rose or orange oil on prefrontal cortex activity; subjective evaluations of relaxation were also determined.
  
  
  METHODS
  Subjects were exposed for 90s to air impregnated with either rose or orange essential oil. As a control, subjects wore the same device but inhaled only unimpregnated air. The three stimuli were randomly presented to each subject.
  
  
  METHODS
  Physiological effects were determined by near-infrared time-resolved spectroscopy and a modified semantic differential approach was used to determine subjective evaluations.
  
  
  RESULTS
  The study participants were 20 female university students (mean age 22.5±1.6 years). Olfactory stimulation by rose or orange oil induced: (1) a significant decrease in oxyhemoglobin concentration in the right prefrontal cortex and (2) an increase in "comfortable," "relaxed," and "natural" feelings.
  
  
  CONCLUSIONS
  These findings indicate that olfactory stimulation by rose or orange oil induces physiological and psychological relaxation.
authors.affiliation: Center for Environment, Health and Field Sciences, Chiba University, Kashiwanoha 6-2-1, Kashiwa, Chiba 277-0882, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Igarashi
authors.affiliation: Center for Environment, Health and Field Sciences, Chiba University, Kashiwanoha 6-2-1, Kashiwa, Chiba 277-0882, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Ikei
authors.affiliation: Center for Environment, Health and Field Sciences, Chiba University, Kashiwanoha 6-2-1, Kashiwa, Chiba 277-0882, Japan.
authors.forename: Chorong
authors.initials: C
authors.lastname: Song
authors.affiliation: Center for Environment, Health and Field Sciences, Chiba University, Kashiwanoha 6-2-1, Kashiwa, Chiba 277-0882, Japan. Electronic address: ymiyazaki@faculty.chiba-u.jp.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Miyazaki
mesh_terms: D000328:Adult; D019341:Aromatherapy; D005260:Female; D006801:Humans; D009822:Oils, Volatile / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects*; D011897:Random Allocation; D027826:Rosa; D012903:Smell / Q000187:drug effects* / Q000502:physiology; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
chemical_list: D009822:Oils, Volatile; D010938:Plant Oils; C087245:orange oil
keywords: Near-infrared spectroscopy; Orange; Physiological relaxation; Rose; Semantic differential method