title: Correlation of within-individual fluctuation of depressed mood with prefrontal cortex activity during verbal working memory task: optical topography study.
abstract: Previous studies showed that interindividual variations in mood state are associated with prefrontal cortex (PFC) activity. In this study, we focused on the depressed-mood state under natural circumstances and examined the relationship between within-individual changes over time in this mood state and PFC activity. We used optical topography (OT), a functional imaging technique based on near-infrared spectroscopy, to measure PFC activity for each participant in three experimental sessions repeated at 2-week intervals. In each session, the participants completed a self-report questionnaire of mood state and underwent OT measurement while performing verbal and spatial working memory (WM) tasks. The results showed that changes in the depressed-mood score between successive sessions were negatively correlated with those in the left PFC activation for the verbal WM task (ρ = -0.56, p < 0.05). In contrast, the PFC activation for the spatial WM task did not co-vary with participants' mood changes. We thus demonstrated that PFC activity during a verbal WM task varies depending on the participant's depressed mood state, independent of trait factors. This suggests that using optical topography to measure PFC activity during a verbal WM task can be used as a potential state marker for an individual's depressed mood state.
authors.affiliation: Hitachi, Ltd., Central Research Laboratory, 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan. hiroki.sato.ry@hitachi.com
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sato
authors.forename: Ryuta
authors.initials: R
authors.lastname: Aoki
authors.forename: Takusige
authors.initials: T
authors.lastname: Katura
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Matsuda
authors.forename: Hideaki
authors.initials: H
authors.lastname: Koizumi
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology*; D000704:Analysis of Variance; D003863:Depression / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000502:physiology*; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D018709:Statistics, Nonparametric; D013647:Task Performance and Analysis