Learning to Read an Alphabet of Human Faces Produces Left-lateralized Training Effects in the Fusiform Gyrus

Abstract

Numerous functional neuroimaging studies have shown that most orthographic stimuli, such as printed English words, produce a left-lateralized response within the fusiform gyrus (FG) at a characteristic location termed the visual word form area (VWFA). We developed an experimental alphabet (FaceFont) comprising 35 face–phoneme pairs to disentangle phonological and perceptual influences on the lateralization of orthographic processing within the FG. Using functional imaging, we found that a region in the vicinity of the VWFA responded to FaceFont words more strongly in trained versus untrained participants, whereas no differences were observed in the right FG. The trained response magnitudes in the left FG region correlated with behavioral reading performance, providing strong evidence that the neural tissue recruited by training supported the newly acquired reading skill. These results indicate that the left lateralization of the orthographic processing is not restricted to stimuli with particular visual-perceptual features. Instead, lateralization may occur because the anatomical projections in the vicinity of the VWFA provide a unique interconnection between the visual system and left-lateralized language areas involved in the representation of speech.

Reading faces: Investigating the use of a novel face-based orthography in acquired alexia

“…These results converge with the neuroimaging findings of Moore et al (2014), who trained young adults to read the FaceFont orthography. After a two-week training period, participants were able to read simple texts written in FaceFont with high levels of comprehension at rates similar to beginning readers of written English.…”

“…In her initial effort, AA1 attempted to learn all 35 of the phonograms in the FaceFont alphabet. AA1 correctly recalled only 5.71% of the face-phoneme mappings when tested after 11 prior exposures to the phonogram set, a level of performance well below that observed in healthy young adults (Moore et al, 2014). In AA1's second FaceFont learning opportunity, we investigated whether she could learn FaceFont phonograms more easily if they were presented in small subsets.…”

“…More specifically, we selected ten phonograms from the FaceFont alphabet (Moore et al, 2014) for further training. These ten phonograms were divided into two five-item subsets containing broadly equivalent face and phoneme types, referred to hereafter as FaceFont A and FaceFont B .…”

“…We developed the FaceFont orthography, which is an alphabetic system comprising 35 face-phoneme pairs, to test two competing accounts for the left-lateralization of the VWFA (Moore, Durisko, Perfetti, & Fiez, 2014). A visuo-perceptual account suggests that orthographic processing preferentially engages the VWFA because printed words impose a high demand on particular types of perceptual analysis that are best mediated by this region (such as high-spatial frequency and feature-based visual processing; McCandliss, Cohen, & Dehaene, 2003).…”

Novel domain formation reveals proto-architecture in inferotemporal cortex

“…Studies in humans have occasionally found shifts in selectivity as a function of training: Moore et al 37 found that learning to read an alphabet of human faces induces responsiveness to those faces in the left fusiform area. Moreover, the part of the brain that is selectively responsive to text in literate humans is, in illiterate people, responsive to faces 38 .…”