Functional Magnetic Resonance Imaging (fMRI) of the Visual Cortex with Wide-View Retinotopic Stimulation

Area of Science:

• Neuroscience
• Radiology
• Ophthalmology

Background:

• Standard functional MRI (fMRI) typically maps a limited visual field (<30°).
• Peripheral and central visual cortex mapping is crucial for understanding visual field defects.
• Existing methods lack comprehensive visual field coverage.

Purpose of the Study:

• To develop and validate a wide-view stimulation system for blood oxygenation level-dependent (BOLD) fMRI.
• To enable functional mapping of the entire peripheral and central visual cortex.
• To provide a tool for evaluating visual cortex changes in eye diseases.

Main Methods:

• Utilized a wide-view presentation system with MR-compatible projectors and a large screen/mirror.
• Employed a standard head coil, positioning the subject for an unobstructed wide-angle view (>100°).
• Applied retinotopic stimulation paradigms to acquire wide-view retinotopic fMRI maps.

Main Results:

• Successfully mapped functional activity across a significantly larger visual field (>100°) compared to standard fMRI.
• Demonstrated the capability to differentiate functional activity in central and peripheral visual cortex regions.
• Validated a practical and easily implementable system for wide-view visual fMRI.

Conclusions:

• Wide-view retinotopic fMRI is a feasible and effective method for comprehensive visual cortex mapping.
• This technique offers a valuable tool for diagnosing and monitoring visual field loss in conditions like glaucoma.
• The system enhances the evaluation of visual brain function in relation to ocular pathologies.