The Face-Processing Network Is Resilient to Focal Resection of Human Visual Cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Visual Perception

Background:

• Human face perception relies on a distributed network in the occipital and temporal lobes, predominantly in the right hemisphere.
• Current theories propose either a hierarchical processing model starting with the occipital face area (OFA) or a nonhierarchical multiple-route network.
• Hierarchical models predict that damage to the OFA will impair subsequent processing stages.

Purpose of the Study:

• To test the prediction of hierarchical models by examining face perception in a patient (Patient S.P.) who underwent surgical removal of the right OFA.
• To investigate the stability and plasticity of the face processing network after focal brain damage.
• To differentiate between hierarchical and nonhierarchical models of face perception.

Main Methods:

• Acquired multiple functional magnetic resonance imaging (fMRI) measurements in Patient S.P. before and after surgery, and in typical controls.
• Conducted within-subject and between-subject comparisons to assess changes in face selectivity and spatial topology.
• Utilized diffusion-weighted imaging to identify white matter connections between retinotopic areas and downstream face-selective regions.

Main Results:

• Downstream face-selective regions maintained stable spatial topology and selectivity 1 and 8 months post-surgery.
• The reliability of face selectivity patterns in Patient S.P. remained consistent before and after resection, comparable to controls.
• While dorsal face regions showed typical visual space representation, ventral regions and V1 in the resected hemisphere exhibited atypical representations.

Conclusions:

• The findings support a multiple-route, nonhierarchical model of face processing, challenging strict hierarchical predictions.
• The resilience of downstream face-selective regions suggests the brain's capacity for adaptation following focal damage.
• White matter connectivity likely plays a crucial role in maintaining network stability and plasticity in high-level visual cortex.