title: Age-dependent change in metabolic response to photic stimulation of the primary visual cortex in infants: functional magnetic resonance imaging study.
abstract: The blood oxygen level-dependent (BOLD) response to photic stimulation in the primary visual cortex (V1) reverses from positive to negative around 8 weeks of age. This phenomenon may be caused by increased oxygen consumption during stimulation as the result of a rapid increase of synaptic density at this age. To test this hypothesis, we applied existing mathematic models of BOLD signals to the experimental data from infants. When the stimulus-related increments of cerebral blood flow and cerebral blood volume were fixed at 60% and 20%, respectively, the mean estimated increment of the cerebral metabolic rate of oxygen of the V1 in the elder infant group (57.1% +/- 8.8%) was twice as large as that in the younger infant group (32.2% +/- 4.7%), which corresponds to the reported difference in synaptic density. The present data confirmed that a change in oxygen consumption could explain a transition from a positive to a negative BOLD response.
authors.affiliation: Department of Radiology, Fukui Medical University, 23 Shimoaizuki, Matsuoka, Yoshida, Fukui 910-1193, Japan. muramoto@fmsrsa.fukui-med.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Muramoto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamada
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sadato
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kimura
authors.forename: Yukuo
authors.initials: Y
authors.lastname: Konishi
authors.forename: Kouki
authors.initials: K
authors.lastname: Kimura
authors.forename: Masato
authors.initials: M
authors.lastname: Tanaka
authors.forename: Takanori
authors.initials: T
authors.lastname: Kochiyama
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Yonekura
authors.forename: Harumi
authors.initials: H
authors.lastname: Ito
mesh_terms: D000367:Age Factors; D001930:Brain Injuries; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008027:Light; D008279:Magnetic Resonance Imaging; D008297:Male; D008962:Models, Theoretical; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D012039:Regional Blood Flow; D012307:Risk Factors; D013569:Synapses; D014793:Visual Cortex / Q000098:blood supply* / Q000254:growth & development / Q000378:metabolism*; D014796:Visual Perception
chemical_list: D010100:Oxygen