title: Near-infrared spectroscopy of orbitofrontal cortex during odorant stimulation.
abstract: BACKGROUND
  For olfaction, several studies have reported near-infrared spectroscopy (NIRS) signal changes in the orbitofrontal cortex (OFC) during odor stimulation. However, the roles of human OFC in olfactory cognition are less well understood. This study was designed to better understand the roles of OFC for olfaction.
  
  
  METHODS
  Hemodynamic responses for phenyl ethyl alcohol or citral in the OFCs were measured with NIRS. After the experiment, participants were asked to describe the characteristics of the odor and to rate odor intensity and hedonic valence.
  
  
  RESULTS
  Statistical analysis of all participants' data showed significant changes in the concentration of total hemoglobin in the left OFC during the trial (p = 0.04). The total hemoglobin signal increased significantly in the right OFC (p = 0.0008) of the participants who successfully identified the odorant stimulus.
  
  
  CONCLUSIONS
  Our findings showed that NIRS combined with a questionnaire is a useful method for studying the functional neuroanatomy of OFC in terms of olfaction.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Kokan
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Sakai
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Doi
authors.forename: Hisami
authors.initials: H
authors.lastname: Fujio
authors.forename: Shingo
authors.initials: S
authors.lastname: Hasegawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tanimoto
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Nibu
mesh_terms: D000080462:Acyclic Monoterpenes; D000293:Adolescent; D002540:Cerebral Cortex; D000431:Ethanol / Q000032:analysis; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism* / Q000528:radiation effects; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007259:Infrared Rays / Q000009:adverse effects; D039821:Monoterpenes / Q000032:analysis; D009445:Neuroanatomy / Q000379:methods / Q000639:trends; D009812:Odorants / Q000032:analysis; D012903:Smell / Q000502:physiology; D019265:Spectroscopy, Near-Infrared; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D000080462:Acyclic Monoterpenes; D006454:Hemoglobins; D039821:Monoterpenes; D000431:Ethanol; C007076:citral