The medial temporal written word processing system.

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• Established models propose parallel routes for written word processing involving visual word form area and temporal/parietal/frontal cortices.
• The perirhinal cortex is recognized as a hub connecting sensory input with broader content representations.

Purpose of the Study:

• To hypothesize an alternative ventromedial occipitotemporal route for written word processing.
• To investigate the role of the left perirhinal cortex in coding the association between concrete written words and their referents.

Main Methods:

• Analysis of direct electrophysiological recordings in humans showing responses to concrete written words.
• Examination of activity patterns in the perirhinal cortex reflecting conceptual similarity between concrete written words.
• Consideration of clinical data from patients with semantic variant primary progressive aphasia and surface alexia.

Main Results:

• Electrophysiological recordings indicate specific responses in the left perirhinal cortex to concrete written words.
• Activity patterns in the perirhinal cortex correlate with the conceptual similarity of concrete written words.
• Damage to the left perirhinal cortex is associated with surface alexia, impairing written word comprehension.

Conclusions:

• The left perirhinal cortex plays a significant role in processing concrete written words via a ventral occipitotemporal pathway.
• This pathway integrates visual object processing mechanisms with written language comprehension.
• The findings offer insights into the neuroanatomical basis of reading and language disorders like surface alexia.