Morphology of primary visual cortex predicts individual differences in fixation duration during text reading

Area of Science:

• Cognitive Neuroscience
• Neuroimaging
• Reading Science

Background:

• Skilled reading involves brief eye fixations on words.
• Computational models like E-Z Reader suggest fixation durations depend on lexical processing.
• Lexical processing relies on efficient visual encoding.

Purpose of the Study:

• To investigate the relationship between individual differences in early visual encoding efficiency and fixation durations during reading.
• To test if structural variations in the primary visual cortex relate to variations in eye movement patterns in skilled readers.

Main Methods:

• Recorded participants' eye movements while they read.
• Analyzed individual differences in fixation duration distributions.
• Correlated fixation duration metrics with primary visual cortex morphology (gray matter surface area and volume) obtained from MRI scans.

Main Results:

• Greater gray matter surface area and volume in the visual cortex were associated with shorter fixation durations.
• Increased gray matter in visual cortex also predicted less variability in fixation durations.
• These findings indicate a link between visual cortex structure and reading eye movement dynamics.

Conclusions:

• Individual differences in eye movement control during skilled reading are influenced by the efficiency of early visual encoding.
• Structural variations in the visual cortex play a role in modulating fixation durations.
• The results support computational models, such as E-Z Reader, that highlight the impact of lexical processing and visual encoding on reading eye movements.