Task dependent lexicality effects support interactive models of reading: A meta-analytic neuroimaging review

Abstract

Models of reading must explain how orthographic input activates a phonological representation, and elicits the retrieval of word meaning from semantic memory. Comparisons between tasks that theoretically differ with respect to the degree to which they rely on connections between orthographic, phonological and semantic systems during reading can thus provide valuable insight into models of reading, but such direct comparisons are not well-represented in the literature. An ALE meta-analysis explored lexicality effects directly contrasting words and pseudowords using the lexical decision task and overt or covert naming, which we assume rely most on the semantic and phonological systems, respectively. Interactions between task and lexicality effects demonstrate that different demands of the lexical decision and naming tasks lead to different manifestations of lexicality effects.

Neural correlates of the lexicality effect in children

“…One indication of a specialization in the left vOT is the dissociation of greater activation for word reading in the anterior part and a greater activation for pseudowords in the mid-posterior part, as found in adults (Cattinelli et al, 2013; Jobard et al, 2003; McNorgan et al, 2015; Price & Mechelli, 2005; Taylor et al, 2013). Examining the lexicality effect on activation along the left vOT cortex in young readers has the potential to shed light on the developmental specialization in this region.…”

“…Neuroimaging meta-analysis studies that examine the lexicality effect (the difference between words and pseudowords) on adults' brain activation suggest that the familiarity and the lexical status of written stimuli affect the degree to which different reading-related brain regions are involved (Cattinelli et al, 2013; Jobard, Crivello, & Tzourio-Mazoyer, 2003; McNorgan, Chabal, O'Young, Lukic, & Booth, 2015; Mechelli et al, 2005; Protopapas et al, 2016; Pugh et al, 2001, 2010; Taylor et al, 2013). Pseudowords as compared to words show greater activation in regions that are associated with spelling to sound mapping, such as the supramarginal gyrus (SMG) and inferior parietal lobule (IPL) (Graves, Binder, Desai, Conant, & Seidenberg, 2010; Jobard et al, 2003), and phonological processing, such as the superior temporal gyrus (STG) and dorsal inferior frontal gyrus (IFG) (Fiez & Petersen, 1998; Richlan, Kronbichler, & Wimmer, 2011; Turkeltaub, Gareau, Flowers, Zeffiro, & Eden, 2003).…”

“…However, the engagement of one mechanism or the other seems to depend on the specific task. While lexical decision tasks tend to increase engagement of semantic and ortho-lexical processing mechanisms, naming tasks tend to increase engagement of spelling to sound mapping mechanisms (Carreiras, Mechelli, Estévez, & Price, 2007; McNorgan et al, 2015). The current study incorporated a phonological rhyming judgment task that is likely to enhance engagement of spelling to sound mapping mechanisms for both words and pseudowords (Pattamadilok et al, 2017).…”

“…Studies with adults further show a dissociation for words and pseudowords in different parts of the left vOT, including the left fusiform gyrus (FG) and ITG. Pseudowords show a greater activation as compared to words in the mid-posterior part (MNI: -50 < Y < -70) (Bruno, Zumberge, Manis, Lu, & Goldman, 2008; Cattinelli et al, 2013; Jobard et al, 2003; McNorgan et al, 2015; Mechelli, Gorno-Tempini, & Price, 2003; Price & Mechelli, 2005; Taylor et al, 2013). This region includes the putative visual word form area (VWFA) and is associated with sub-lexical bigrams and single letter coding (Dehaene, Cohen, Sigman, & Vinckier, 2005; Kronbichler et al, 2004).…”

“…The greater activation for pseudowords as compared to words in the mid-posterior part of the left vOT in adult readers can be explained by a greater prediction error from the top-down processes for the phonologically and semantically unfamiliar pseudowords. Real words, on the other hand, show greater activation as compared to pseudowords in the anterior part of the left vOT (MNI: -30 < Y < -50) (Cattinelli et al, 2013; Jobard et al, 2003; McNorgan et al, 2015; Price & Mechelli, 2005; Taylor et al, 2013). This region is associated with coding of larger orthographic units (morphemes, small words, and up) (Dehaene et al, 2005).…”