title: Altered resting-state activity in seasonal affective disorder.
abstract: At present, our knowledge about seasonal affective disorder (SAD) is based mainly up on clinical symptoms, epidemiology, behavioral characteristics and light therapy. Recently developed measures of resting-state functional brain activity might provide neurobiological markers of brain disorders. Studying functional brain activity in SAD could enhance our understanding of its nature and possible treatment strategies. Functional network connectivity (measured using ICA-dual regression), and amplitude of low-frequency fluctuations (ALFF) were measured in 45 antidepressant-free patients (39.78 ± 10.64, 30 ♀, 15 ♂) diagnosed with SAD and compared with age-, gender- and ethnicity-matched healthy controls (HCs) using resting-state functional magnetic resonance imaging. After correcting for Type 1 error at high model orders (inter-RSN correction), SAD patients showed significantly increased functional connectivity in 11 of the 47 identified RSNs. Increased functional connectivity involved RSNs such as visual, sensorimotor, and attentional networks. Moreover, our results revealed that SAD patients compared with HCs showed significant higher ALFF in the visual and right sensorimotor cortex. Abnormally altered functional activity detected in SAD supports previously reported attentional and psychomotor symptoms in patients suffering from SAD. Further studies, particularly under task conditions, are needed in order to specifically investigate cognitive deficits in SAD.
authors.affiliation: Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Abou Elseoud
authors.forename: Juuso
authors.initials: J
authors.lastname: Nissilä
authors.forename: Anu
authors.initials: A
authors.lastname: Liettu
authors.forename: Jukka
authors.initials: J
authors.lastname: Remes
authors.forename: Jari
authors.initials: J
authors.lastname: Jokelainen
authors.forename: Timo
authors.initials: T
authors.lastname: Takala
authors.forename: Antti
authors.initials: A
authors.lastname: Aunio
authors.forename: Tuomo
authors.initials: T
authors.lastname: Starck
authors.forename: Juha
authors.initials: J
authors.lastname: Nikkinen
authors.forename: Hannu
authors.initials: H
authors.lastname: Koponen
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Zang
authors.forename: Osmo
authors.initials: O
authors.lastname: Tervonen
authors.forename: Markku
authors.initials: M
authors.lastname: Timonen
authors.forename: Vesa
authors.initials: V
authors.lastname: Kiviniemi
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D012146:Rest; D016574:Seasonal Affective Disorder / Q000503:physiopathology*