Imaging brain activity during natural vision using CASL perfusion fMRI

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Functional MRI (fMRI) is increasingly used to study brain activity in naturalistic settings.
• Arterial spin labeling (ASL) perfusion fMRI offers stable, noninvasive quantification of cerebral blood flow (CBF), ideal for sustained brain activity.
• Previous studies often focused on controlled, non-naturalistic tasks.

Purpose of the Study:

• To investigate brain activation patterns during natural vision using ASL perfusion fMRI.
• To concurrently measure cerebral blood flow (CBF) and blood oxygen level-dependent (BOLD) signals.
• To explore the relationship between brain activity and motion perception during naturalistic viewing.

Main Methods:

• ASL perfusion fMRI was employed to measure CBF and BOLD contrasts in subjects freely viewing a cartoon movie.
• Quantitative whole-brain and regional CBF values were calculated during movie viewing and resting states.
• Regression and region of interest analyses were performed to correlate brain activity with motion perception.

Main Results:

• ASL perfusion fMRI reliably quantified CBF during natural vision, showing increases in visual and frontal areas and decreases in ventromedial frontal and superior temporal cortex.
• BOLD contrast revealed similar but less pronounced activation and deactivation patterns.
• Significant associations were found between middle temporal (MT) region activation and motion perception intensity.

Conclusions:

• ASL perfusion fMRI is feasible for imaging sustained and dynamic neural activation in naturalistic conditions.
• The findings support the concept of maintained functional segregation and specialization during natural vision.
• CBF and BOLD signals in the MT region are sensitive to motion perception intensity during natural viewing.