Visual Word Form Area demonstrates individual and task-agnostic consistency but inter-individual variability

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Visual Perception

Background:

• The Ventral Occipital Temporal Cortex (VOTC) exhibits categorical functional specialization for visual stimuli.
• The Visual Word Form Area (VWFA), crucial for reading, is located in the left VOTC but shows significant individual variability in size and precise location.
• Ongoing debate exists on whether the VWFA primarily processes visual features of text or is driven by reading tasks.

Purpose of the Study:

• To investigate the consistency of VWFA location across individuals and tasks.
• To determine the impact of different tasks on the extent of text-selective responses.
• To examine the effect of individual anatomical variability on identifying text-selective cortex in template space.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan adults and children.
• Participants viewed text, pseudo-fonts, faces, objects, and limbs under two conditions: a fixation task and a one-back task.
• Region of Interest (ROI) analysis was performed on individual cortical surfaces and in template space.

Main Results:

• A consistent VWFA location was identifiable on each individual's cortical surface using either task.
• The one-back task elicited a larger text-selective response territory (ROI) compared to the fixation task.
• Averaging data in template space obscured text-selective cortex due to high inter-individual variability in the arrangement of category-selective regions.
• These findings were consistent across developmental stages.

Conclusions:

• Individual VWFA location is task-agnostic, but task demands influence the extent of the activated region.
• High anatomical variability in VOTC category-selective regions prevents reliable identification of VWFA in averaged template space.
• Understanding individual variability is crucial for studying the neural basis of reading and its development.