Abstract
Reading involves the recognition of words on the basis of shape information; different words are specified by different strings of letter shapes. Reading also involves the recognition of a word presented in different fonts; word identity is invariant to font changes. We used fMRI to study the neural responses to changes in word identity and font in visual cortex. We measured fMRI responses to four-letter words which either changed or repeated in the following ways: (1) the same word was repeated in the same font; (2) the same word was repeated in different fonts; (3) different words were presented in different fonts. We also employed two additional conditions in which either the right or left half of words changed while the other half remained the same (words were split at fixation), which allowed us to dissociate the effects of hemifield-specific letter identity and font changes between the two hemispheres. Our primary finding was that changes in identity resulted in left lateralized fMRI responses in visual cortex, most notably in an area of occipitotemporal cortex corresponding to the visual word form area (VWFA), but also in more posterior portions of visual cortex. In contrast, fMRI responses to font changes in the absence of identity changes were not lateralized, but nevertheless overlapped highly with the left lateralized fMRI responses observed in our other conditions. Our results support the view that both visual cortical hemispheres represent shape information during word recognition and that the left occipitotemporal cortex represents word identity.
Meeting abstract presented at VSS 2014