Individual variation in the functional lateralization of human ventral temporal cortex: Local competition and...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• The ventral temporal cortex (VTC) is crucial for high-level vision and exhibits functional lateralization.
• Word perception is typically left-lateralized, while face perception is right-lateralized in the VTC.
• The precise mechanisms driving face lateralization, particularly its rightward bias, remain debated.

Purpose of the Study:

• To investigate the underlying mechanisms of VTC functional lateralization, specifically for face and word processing.
• To test theories involving local competition versus long-range coupling in shaping VTC organization.
• To differentiate between specific face-word competition and more general representational interactions.

Main Methods:

• Utilized functional MRI (fMRI) data from an in-house experiment and the Human Connectome Project (HCP) dataset.
• Calculated laterality indices (LIs) for word, face, object, tool, and body selectivity.
• Analyzed correlations between LIs across different brain regions and processing categories.

Main Results:

• No evidence of local competition between word and face selectivity in the VTC.
• Face and tool selectivity LIs were anti-correlated, while face and body LIs were positively correlated, suggesting generic local interactions.
• VTC face laterality correlated negatively with language LI and positively with social processing LI in distinct posterior temporal lobe subregions.

Conclusions:

• VTC organization is shaped by general local representational interactions rather than specific local competition between words and faces.
• Face laterality in the VTC is influenced by long-range coupling with social processing networks in the posterior temporal lobe.
• Rightward face lateralization may arise from local competition between social and language processing in the posterior temporal lobe.