2B, β = 0.834, uncorrected p = 0.006, CX-4945 q = 0.032). Although there appears to be an outlier in Fig. 2C (corresponding to the participant ranked 18), its influence was minimized

by converting all values to ranks (see Section 2). Pathways through pOTS-ITS, pOTS-pMTG, ITS-pSTG, pMTG-pSTG, and pMTG-AG were not significantly correlated with imageability effects. No reliable associations were found between pathway volumes and age, level of education, or behavioral effects of word frequency, consistency, letter length, the interaction of word frequency and consistency, or the interaction of consistency and imageability ( Table 1). The specificity of the findings to imageability JQ1 and not the other tested factors makes it unlikely that the findings are due to individual differences in ROI volumes or group differences in pathway volumes. In fact, imageability effects across participants did not significantly correlate with ROI volumes for any of the ROIs. Volumes for both the ROIs and the examined pathways are given for reference in Table 2. Overall, these findings (1) identify novel structural brain correlates underlying individual differences

in reading, and (2) reveal functional–anatomical pathways supporting the mapping between semantics and phonology in reading aloud. To situate these findings within the context of known major white matter pathways, we created an overlap image in Talairach space of the AG-pSTG pathways from each of the individual subjects, and did the same for the ITS-pMTG pathways. These PAK5 were thresholded so that only tracts co-occurring in at least 9 (50%) of the participants were displayed. Probabilistic maps of major known tracts from the Johns Hopkins

University (JHU) white matter atlas were also registered to Talairach space and thresholded at 50% (Hua et al., 2008). As can be seen in Fig. 3A, the AG-pSTG pathway encompassed the parieto-temporal branch of the superior longitudinal fasciculus (SLF-PT), while also extending beyond it. The SLF-PT may correspond to the posterior segment of the arcuate fasciculus as identified by Catani and Jones (2005). One difference between the SLF-PT and the current AG-pSTG pathway, however, is that the latter extends to the AG, while the SFL-PT appears to lie mainly in the posterior peri-Sylvian white matter. The ITS-pMTG pathway overlapped most closely with the inferior longitudinal fasciculus (ILF), though the course of the ILF had a longer extent in the anterior and posterior directions (Fig. 3B). Defining pathways using spherical ROIs near the ends of these known tracts as waypoints, however, did not yield significant correlations with imageability (for ILF: β = 0.758; for parieto-temporal branch of arcuate: β = 0.327; for fronto-temporal branch of arcuate: β = 0.566; all q > 0.1).