title: Correlation between asymmetry of spontaneous oscillation of hemodynamic changes in the prefrontal cortex and anxiety levels: a near-infrared spectroscopy study.
abstract: According to the valence asymmetry hypothesis, the left/right asymmetry of prefrontal cortex (PFC) activity is correlated with specific emotional responses to mental stress and personality traits. Here, we evaluated the relation between emotional state and asymmetry in PFC activity at rest by using near-infrared spectroscopy (NIRS). We measured spontaneous oscillation of oxyhemoglobin (oxy-Hb) concentrations in the bilateral PFC at rest in normal adults employing two-channel NIRS. In order to analyze left/right asymmetry of PFC activity at rest, we calculated the laterality index at rest (LIR) (see text). We investigated the correlation between the LIR and anxiety levels evaluated by the State-Trait Anxiety Inventory (STAI) test. We found that the right PFC was more active at rest than the left PFC, corresponding to a higher anxiety level measured by the STAI; that is, subjects with right-dominant activity at rest showed higher STAI scores, while those with left-dominant oxy-Hb changes at rest showed lower STAI scores. Aging had no significant effect on the relation. The present results obtained by NIRS are consistent with the valence asymmetry hypothesis. We emphasize NIRS may be a useful tool for objective assessment of anxiety levels.
authors.affiliation: Waseda University, Department of Electrical Engineering and Bioscience, Tokyo 169-8555, Japan.
authors.forename: Wakana
authors.initials: W
authors.lastname: Ishikawa
authors.affiliation: Waseda University, Department of Electrical Engineering and Bioscience, Tokyo 169-8555, Japan.
authors.forename: Masakaze
authors.initials: M
authors.lastname: Sato
authors.affiliation: Waseda University, Department of Electrical Engineering and Bioscience, Tokyo 169-8555, Japan.
authors.forename: Yukikatsu
authors.initials: Y
authors.lastname: Fukuda
authors.affiliation: Waseda University, Department of Electrical Engineering and Bioscience, Tokyo 169-8555, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Nihon University, NEWCAT Institute, College of Engineering, Department of Electrical and Electronics Engineering, Fukushima 963-8642, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Takemura
authors.affiliation: Nihon University, NEWCAT Institute, College of Engineering, Department of Electrical and Electronics Engineering, Fukushima 963-8642, JapancNihon University, School of Medicine, Department of Neurological Surgery, Tokyo 173-8610, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakatani
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D001007:Anxiety / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000098:blood supply*; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D055815:Young Adult