Position selectivity in face-sensitive visual cortex to facial and nonfacial stimuli: an fMRI study

Area of Science:

• Neuroscience
• Visual Perception
• Cognitive Neuroscience

Background:

• Evidence suggests object-selective visual areas are position-sensitive.
• Previous studies often used specific stimuli or small cortical sections.
• Visual field maps in cortex are extensive but typically exclude face-selective areas.

Purpose of the Study:

• To investigate position sensitivity in the occipital face area (OFA) and fusiform face area (FFA).
• To compare the position sensitivity of OFA and FFA using retinotopic mapping and face stimuli.
• To explore novel analysis methods for fMRI data in face perception.

Main Methods:

• fMRI was employed to assess OFA and FFA responses to retinotopic mapping stimuli and synthetic faces.
• Standard univariate BOLD signals and multivoxel pattern analysis (MVPA) were used.
• Novel methods included voxel distribution analysis and cross-classification of retinotopic and face stimuli responses.

Main Results:

• Both OFA and FFA showed polar angle sensitivity, with OFA having a stronger contralateral bias and FFA a stronger vertical meridian bias.
• Both areas exhibited contralateral hemispheric lateralization for face stimuli.
• Classifiers based on polar angle responsivity could predict face stimuli activation in OFA but not FFA.

Conclusions:

• OFA and FFA are quadrant-sensitive to face stimuli.
• OFA exhibits greater position responsivity than FFA.
• These findings support varying position sensitivity across occipito-temporal cortex surfaces.