Comparing different stimulus configurations for population receptive field mapping in human fMRI

Area of Science:

• Neuroscience
• Visual Perception
• Functional Magnetic Resonance Imaging (fMRI)

Background:

• Population receptive field (pRF) mapping quantifies human visual receptive field properties using fMRI.
• Systematic investigation of stimulus configuration effects on pRF estimates is lacking.

Purpose of the Study:

• To compare the impact of different stimulus configurations on model-based pRF estimation.
• To evaluate the influence of eccentricity scaling and coordinate systems on pRF parameters.
• To compare eccentricity estimates between phase-encoded and model-based pRF approaches.

Main Methods:

• Compared three stimulus configurations: size-invariant Cartesian bars, eccentricity-scaled Cartesian bars, and polar-coordinate wedge-and-ring stimuli.
• Utilized a model-based approach for pRF estimation in the human visual cortex.
• Analyzed goodness of fit, pRF size, and eccentricity estimates.

Main Results:

• Eccentricity scaling significantly affected goodness of fit and pRF size estimates.
• Stimulus configuration influenced pRF size variability, especially in higher visual areas (e.g., V5/MT+).
• Phase-encoded methods tended to yield more peripheral eccentricity estimates compared to model-based approaches.

Conclusions:

• Eccentricity scaling and polar coordinate systems are critical for optimizing pRF mapping experimental design.
• Simultaneous wedge and ring stimulation offers higher fit reliability and reduced acquisition time.
• Careful consideration of stimulus configuration is essential for accurate pRF estimation.