Abstract
The visual word form area in the occipitotemporal sulcus, here referred to as OTS-words, responds more strongly to text than other visual stimuli and plays a critical role in reading. Here we hypothesized, that this regions preference for text may be driven by a preference for reading tasks, as in most prior fMRI studies only the text stimuli were readable. To test this, we performed three fMRI experiments (N=15) and systematically varied the participant’s task and the visual stimulus, investigating mOTS-words and pOTS-words subregions. In experiment 1, we contrasted text stimuli with non-readable visual stimuli (faces, limbs, houses, and objects). In experiment 2, we used a fMRI adaptation paradigm, presenting the same or different compound words in text or emoji formats. In experiment 3, participants performed either a reading or a color task on compound words, presented in text or emoji format. Using experiment 1 data, we identified left mOTS-words and pOTS-words in all participants by contrasting text stimuli with non-readable stimuli. In experiment 2, pOTS-words, but not mOTS-words, showed fMRI adaptation for compound words in both text and emoji formats. In experiment 3, surprisingly, both mOTS-words and pOTS-words showed higher responses to compound words in emoji than text formats. Moreover, mOTS-words, but not pOTS-words, also showed higher responses during the reading than color task and more so for words in the emoji format. Multivariate analyses of experiment 3 data showed that distributed responses in pOTS-words encode the visual stimulus, whereas distributed responses in mOTS-words encode both the stimulus and the task. Together, our findings suggest that the function of the OTS-words subregions goes beyond the specific visual processing of text and that these regions are flexibly recruited whenever semantic meaning needs to be assigned to visual input.