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Updated: Sep 28, 2026
Functional Magnetic Resonance Imaging (fMRI) of the Visual Cortex with Wide-View Retinotopic Stimulation
Published on: December 8, 2023
Age-dependent change in metabolic response to photic stimulation of the primary visual cortex in infants: functional
Satoshi Muramoto1, Hiroki Yamada, Norihiro Sadato
1Department of Radiology, Fukui Medical University, 23 Shimoaizuki, Matsuoka, Yoshida, Fukui 910-1193, Japan. muramoto@fmsrsa.fukui-med.ac.jp
Insights
The blood oxygen level-dependent (BOLD) response in infant visual cortex shifts from positive to negative due to increased oxygen consumption, linked to synaptic development. This finding explains the BOLD signal transition in early development.
Area of Science:
- Neuroscience
- Developmental Biology
- Medical Imaging
Background:
- The blood oxygen level-dependent (BOLD) signal in the primary visual cortex (V1) of infants undergoes a notable transition.
- This BOLD response reverses from positive to negative around 8 weeks of age, a change potentially linked to neural development.
Purpose of the Study:
- To investigate the hypothesis that increased oxygen consumption, driven by synaptic density changes, causes the BOLD signal reversal in V1 during early development.
- To quantitatively assess the relationship between synaptic density and metabolic changes reflected in the BOLD signal.
Main Methods:
- Mathematical models of BOLD signals were applied to experimental data from infant participants.
- Stimulus-related increments in cerebral blood flow (60%) and cerebral blood volume (20%) were held constant to isolate metabolic rate changes.
Main Results:
- The estimated increment in the cerebral metabolic rate of oxygen (CMRO2) in the V1 of older infants (57.1% +/- 8.8%) was approximately double that of younger infants (32.2% +/- 4.7%).
- This observed difference in CMRO2 directly correlates with the known differences in synaptic density between the infant age groups.
Conclusions:
- The study confirms that changes in oxygen consumption are a key factor explaining the developmental transition from a positive to a negative BOLD response in the infant visual cortex.
- Increased synaptic density during early development leads to higher metabolic demands, altering the BOLD signal characteristics.
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.
