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Published on: February 15, 2014
Development of BOLD signal hemodynamic responses in the human brain
Tomoki Arichi1, Gianlorenzo Fagiolo, Marta Varela
1Centre for the Developing Brain, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
Insights
The hemodynamic response function (HRF) in infants changes with age, impacting functional magnetic resonance imaging (fMRI) analysis. Understanding this brain development is crucial for accurate fMRI studies in neonates.
Area of Science:
- Neuroscience
- Developmental Biology
- Medical Imaging
Background:
- The hemodynamic response function (HRF) is critical for functional magnetic resonance imaging (fMRI) analysis.
- Developmental changes in rodent brains suggest similar maturational trends in human infants' hemodynamic responses.
- Accurate HRF characterization is essential for reliable fMRI in pediatric populations.
Purpose of the Study:
- To characterize the hemodynamic response function (HRF) in human infants before and after birth.
- To investigate age-related changes in the blood oxygen level dependent (BOLD) signal response.
- To improve the precision of fMRI analysis in developing populations.
Main Methods:
- Utilized rapid sampling of the blood oxygen level dependent (BOLD) signal.
- Employed a somatosensory stimulus with an event-related experimental design.
- Collected data from healthy adults, term-corrected infants, and preterm infants.
Main Results:
- Identified a positive amplitude HRF waveform across all subject groups.
- Observed a systematic maturational trend: decreasing time-to-peak and increasing positive peak amplitude with age.
- Demonstrated improved fMRI analysis precision using age-appropriate HRF models.
Conclusions:
- The brain's response to stimuli undergoes structured development from the last trimester of gestation onwards.
- Age-specific HRF models enhance the accuracy of fMRI in infants.
- Findings provide insights into neurodevelopmental changes measurable by fMRI.
Abstract:
In the rodent brain the hemodynamic response to a brief external stimulus changes significantly during development. Analogous changes in human infants would complicate the determination and use of the hemodynamic response function (HRF) for functional magnetic resonance imaging (fMRI) in developing populations. We aimed to characterize HRF in human infants before and after the normal time of birth using rapid sampling of the blood oxygen level dependent (BOLD) signal. A somatosensory stimulus and an event related experimental design were used to collect data from 10 healthy adults, 15 sedated infants at term corrected post menstrual age (PMA) (median 41+1 weeks), and 10 preterm infants (median PMA 34+4 weeks). A positive amplitude HRF waveform was identified across all subject groups, with a systematic maturational trend in terms of decreasing time-to-peak and increasing positive peak amplitude associated with increasing age. Application of the age-appropriate HRF models to fMRI data significantly improved the precision of the fMRI analysis. These findings support the notion of a structured development in the brain's response to stimuli across the last trimester of gestation and beyond.
