, 2010; restricted to not extend
beyond the atlas definition of the fusiform gyrus), a property of the pOTS reported in previous studies (Bruno et al., 2008 and Kronbichler et al., 2004). Finally, although our hypotheses primarily concern posterior temporo-parietal regions thought to be involved in the computation of orthography, phonology, and semantics leading up to word pronunciation (i.e., the regions in Fig. 4), an ROI located primarily in the pars opercularis and triangularis of the inferior frontal gyrus (IFG) was also included. This ROI was defined based on word-frequency related activation in the IFG from Graves et Bleomycin mouse al. (2010; masked to ensure it did not extend beyond the atlas definition of the IFG). There is ample evidence suggesting a role for this region in aspects of phonological processing (Bookheimer, 2002, Katz et al., 2005 and Sandak et al., 2004), although the degree to which activations in
this region are distinguishable from effects of working memory or time-on-task is unclear (Binder et al., 2005, Cattinelli et al., 2013, Graves et al., 2010 and Taylor et al., 2013). The participants considered here are a subset of those involved in a previous fMRI study (N = 20; Graves et al., 2010). DTI data were collected on 18 (12 female) healthy, literate adults who spoke English as a first language. Their mean age was 23.1 (SD: 3.6), mean years of education 16.6 (SD: 3.3). All had normal or corrected-to-normal vision and were right-handed on the Edinburgh handedness inventory ( Oldfield, 1971). Trichostatin A price A verbal IQ estimate from the Wechsler Test of Adult Reading ( Wechsler, 2001) PI-1840 showed a mean standard score of 109.3 (SD: 8.4). All participants provided written consent and were paid an hourly stipend
according to local Institutional Review Board protocols. Details of the stimuli and task are provided in Graves et al. (2010). The most relevant points to emphasize for the current analysis are that the task was reading aloud, and the stimuli consisted of 465 words for which length in letters, spelling-sound consistency, word frequency, imageability, bigram frequency, and biphone frequency were all uncorrelated. Graves et al. reported that imageability of the stimuli was uncorrelated with word frequencies from a large text-based corpus (Baayen, Piepenbrock, & Gulikers, 1995); it is also uncorrelated with frequencies from a corpus of spoken English (Brysbaert & New, 2009), (r = 0.08, p > 0.05). To address whether skilled readers differ in the degree to which they use semantic information in reading aloud, we analyzed RTs using multiple linear regression with the following 6 explanatory variables: length in letters, word frequency, consistency, imageability, the multiplicative interaction of word frequency and consistency, and the multiplicative interaction of consistency and imageability.