title: Reduced frontopolar activation during verbal fluency task associated with poor social functioning in late-onset major depression: Multi-channel near-infrared spectroscopy study.
abstract: OBJECTIVE
  Functional neuroimaging studies to date have indicated prefrontal dysfunction in late-onset major depression (LOD). The relationships between prefrontal dysfunction and clinical characteristics including social functioning, however, have been unclear. The objective of the present study was to evaluate prefrontal hemodynamic response related to an executive task in LOD and to assess the relationship between activation in the prefrontal regions and clinical characteristics including social functioning.
  
  
  METHODS
  Twenty-four subjects with LOD and 30 age- and gender-matched healthy subjects were recruited for the present study. Hemoglobin concentration changes in the prefrontal and superior temporal cortical surface area were measured during verbal fluency task (VFT) using 52-channel near-infrared spectroscopy (NIRS), which enables real-time monitoring of cerebral blood volume (CBV) in the cortical surface area.
  
  
  RESULTS
  The two groups had a distinct spatiotemporal pattern of oxy-hemoglobin concentration change; LOD patients had less activation in a broad area covering both prefrontal and superior temporal cortices than healthy controls. In addition, reduced activation of the frontopolar region had a significant positive correlation with lower self-assessment of social functioning scores in the patient group.
  
  
  CONCLUSIONS
  Reduced frontopolar cortical activation was associated with social functioning impairment in patients with LOD, and NIRS may be an efficient clinical tool for monitoring these characteristics.
authors.affiliation: Division of Neuropsychiatry, Department of Multidisciplinary Internal Medicine, Tottori University Faculty of Medicine, Yonago, Tottori, Japan.
authors.forename: Shenghong
authors.initials: S
authors.lastname: Pu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsumura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Satoru
authors.initials: S
authors.lastname: Ikezawa
authors.forename: Hideaki
authors.initials: H
authors.lastname: Mitani
authors.forename: Akiko
authors.initials: A
authors.lastname: Adachi
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Nakagome
mesh_terms: D017668:Age of Onset; D000368:Aged; D002560:Cerebrovascular Circulation / Q000502:physiology; D003865:Major Depressive Disorder / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010108:Oxyhemoglobins / Q000378:metabolism; D017397:Prefrontal Cortex / Q000098:blood supply / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology*; D012647:Self-Assessment; D012920:Social Behavior Disorders / Q000503:physiopathology* / Q000523:psychology*; D019265:Spectroscopy, Near-Infrared; D013702:Temporal Lobe / Q000098:blood supply / Q000378:metabolism; D014705:Verbal Behavior / Q000502:physiology*
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins