Decrease in fMRI brain activation during working memory performed after sleeping under 10 lux light.
The aim of this study was to investigate the effect of exposure to dim light at night (dLAN) when sleeping on functional brain activation during a working-memory tasks. We conducted the brain functional magnetic resonance imaging (fMRI) analysis on 20 healthy male subjects. All participants slept in a polysomnography laboratory without light exposure on the first and second nights and under a dim-light condition of either 5 or 10 lux on the third night. The fMRI scanning was conducted during n-back tasks after second and third nights. Statistical parametric maps revealed less activation in the right inferior frontal gyrus (IFG) after exposure to 10-lux light. The brain activity in the right and left IFG areas decreased more during the 2-back task than during the 1- or 0-back task in the 10-lux group. The exposure to 5-lux light had no significant effect on brain activities. The exposure to dLAN might influence the brain function which is related to the cognition.
Department of Psychiatry, Gil Medical Center, Gachon University, School of Medicine, Incheon, Korea.
Seung-Gul
SG
Kang
Department of Psychiatry, Korea University College of Medicine, Seoul, Korea.
Ho-Kyoung
HK
Yoon
Department of Psychiatry, Korea University College of Medicine, Seoul, Korea.
Chul-Hyun
CH
Cho
Department of Anatomy, Korea University College of Medicine, Seoul, Korea.
Soonwook
S
Kwon
Department of Biomedical Science, Korea University College of Medicine, Seoul, Korea.
June
J
Kang
Department of Psychiatry, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea.
Young-Min
YM
Park
Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea.
Eunil
E
Lee
Department of Psychiatry, Korea University College of Medicine, Seoul, Korea.
Leen
L
Kim
Department of Psychiatry, Korea University College of Medicine, Seoul, Korea.
Heon-Jeong
HJ
Lee
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*