Age-dependent change in metabolic response to photic stimulation of the primary visual cortex in infants: functional magnetic resonance imaging study.
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.
Muramoto
Satoshi
S
Department of Radiology, Fukui Medical University, 23 Shimoaizuki, Matsuoka, Yoshida, Fukui 910-1193, Japan. muramoto@fmsrsa.fukui-med.ac.jp
Yamada
Hiroki
H
Sadato
Norihiro
N
Kimura
Hirohiko
H
Konishi
Yukuo
Y
Kimura
Kouki
K
Tanaka
Masato
M
Kochiyama
Takanori
T
Yonekura
Yoshiharu
Y
Ito
Harumi
H
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
D010100:Oxygen