The visual word form area is organized according to orthography.
Efficient word reading depends on a left fusiform brain region, the Visual Word Form Area (VWFA). The internal organization of this brain area is currently unknown, as are the potential factors that might underlie this organization. Here we combine functional magnetic resonance imaging (fMRI) with multi-voxel pattern analyses (MVPA) to probe the internal organization of the VWFA. Our findings reveal distinct activation patterns in the VWFA associated with individual letter strings, as well as for pictures. This result demonstrates that the VWFA is organized in such a way that similar words (as well as pictures) activate neurons consistently, irrespective of their exact visual appearance or location. The activation patterns for letter strings were driven primarily by orthographic similarity, and we observed no effects of semantics or lexical status (words versus pseudowords). This effect of orthographic similarity was significant only in the VWFA and not in retinotopic areas and object-selective control regions. Given the relationships between the internal organization and how visual input is processed in a brain region, our findings provide important constraints for computational models of how visual word forms are represented in the brain.
Laboratory of Experimental Psychology, University of Leuven, Belgium. wouter.braet@gmail.com
Wouter
W
Braet
Johan
J
Wagemans
Hans P
HP
Op de Beeck
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000502:physiology; D009778:Occipital Lobe / Q000502:physiology; D010775:Photic Stimulation; D011932:Reading; D012044:Regression Analysis; D012160:Retina / Q000502:physiology; D012660:Semantics; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult