Identity versus similarity priming for letters in left mid-fusiform cortex.

Using functional magnetic resonance imaging, this study examined neural responses in the Visual Word Form Area to prime - test letter pairs in which visual similarity and identity were manipulated. Results revealed the greatest priming for pairs with high visual similarity, less priming for pairs with medium similarity, and the least priming for pairs with low similarity. Moreover, when visual similarity was equated, priming magnitude did not differ for pairs with the same letter identity compared with those with different letter identities. As such, results contrast with views of the Visual Word Form Area as supporting arbitrary (nonsimilarity based) mapping requirements of reading, and suggest a less modular perspective on visual form recognition.