The visual word form system in context.
Woodhead ZV., Brownsett SL., Dhanjal NS., Beckmann C., Wise RJ.
According to the "modular" hypothesis, reading is a serial feedforward process, with part of left ventral occipitotemporal cortex the earliest component tuned to familiar orthographic stimuli. Beyond this region, the model predicts no response to arrays of false font in reading-related neural pathways. An alternative "connectionist" hypothesis proposes that reading depends on interactions between feedforward projections from visual cortex and feedback projections from phonological and semantic systems, with no visual component exclusive to orthographic stimuli. This is compatible with automatic processing of false font throughout visual and heteromodal sensory pathways that support reading, in which responses to words may be greater than, but not exclusive of, responses to false font. This functional imaging study investigated these alternative hypotheses by using narrative texts and equivalent arrays of false font and varying the hemifield of presentation using rapid serial visual presentation. The "null" baseline comprised a decision on visually presented numbers. Preferential activity for narratives relative to false font, insensitive to hemifield of presentation, was distributed along the ventral left temporal lobe and along the extent of both superior temporal sulci. Throughout this system, activity during the false font conditions was significantly greater than during the number task, with activity specific to the number task confined to the intraparietal sulci. Therefore, both words and false font are extensively processed along the same temporal neocortical pathways, separate from the more dorsal pathways that process numbers. These results are incompatible with a serial, feedforward model of reading.