Layer-specific BOLD effects in gradient and spin-echo acquisitions in somatosensory cortex
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View abstract on PubMed
Summary
This summary is machine-generated.Spin-echo (SE) BOLD signals offer clearer insights into neural activity than gradient-echo (GE) signals, especially at high magnetic fields. SE signals are less influenced by large vessels, providing more accurate functional MRI data.
Area Of Science
- Neuroimaging
- Functional Magnetic Resonance Imaging (fMRI)
Background
- Gradient echo (GE) BOLD signals exhibit varied cortical depth distributions.
- Understanding vascular geometry's impact on BOLD signals is crucial for interpreting fMRI data.
Purpose Of The Study
- Compare GE and spin-echo (SE) BOLD signal magnitudes and layer distributions.
- Investigate somatosensory cortex responses to tactile stimulation and resting state at high field (9.4T).
Main Methods
- Used block-design tactile stimulation in squirrel monkeys (Areas 3b and 1).
- Calculated layer-specific connectivities from resting-state data.
- Compared signal power spectra and transverse relaxation rate changes with theoretical models.
Main Results
- SE signals showed 26% lower percentage signal change and slower time course than GE during stimulation.
- GE signals decreased with cortical depth, while SE signals remained consistent but weaker in lower layers.
- GE revealed greater top-layer connectivity between Areas 3b and 1; SE showed minimal changes.
Conclusions
- SE BOLD signals at high field are primarily sensitive to microvascular changes linked to neural activity.
- GE BOLD signals are not solely dominated by large vessels, even in superficial cortical layers.
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