The interaction between orthographic and phonological information in children: an fMRI study

Abstract

We examined the neural representations of orthographic and phonological processing in children, while manipulating the consistency between orthographic and phonological information. Participants, aged 9-15, were scanned while performing rhyming and spelling judgments on pairs of visually presented words. The orthographic and phonological similarity between words in the pair was independently manipulated, resulting in four conditions. In the nonconflicting conditions, both orthography and phonology of the words were either (1) similar (lime-dime) or (2) different (staff-gain); in conflicting conditions, words had (3) similar phonology and different orthography (jazz-has) or (4) different phonology and similar orthography (pint-mint). The comparison between tasks resulted in greater activation for the rhyming task in bilateral inferior frontal gyri (BA 45/47), and greater activation for the spelling task in bilateral inferior/superior parietal lobules (BA 40/7), suggesting greater involvement of phonological and semantic processing in the rhyming task, and nonlinguistic spatial processing in the spelling task. Conflicting conditions were more difficult in both tasks and resulted in greater activation in the above regions. The results suggest that when children encounter inconsistency between orthographic and phonological information they show greater engagement of both orthographic and phonological processing.

Figure 1

A: Language‐specific activation (words > perceptuals) in the spelling (blue) and rhyming (red) tasks, and their overlap (purple). Activation is masked by the map of words > fixation. The coordinates corresponding to the proposed Visual Word Form Area (Dehaene et al., 2004) are presented in a green mark. B: Task‐specific activation: red = rhyming > spelling, blue = spelling > rhyming. C: Overlay of language‐specific and task‐specific activation in the spelling task: yellow = words > perceptuals, cyan = spelling > rhyming, green = overlap. IFG, inferior frontal gyrus; ITG, inferior temporal gyrus; STG, superior temporal gyrus; IPL, inferior parietal lobule; SPL, superior parietal lobule; Prec, precuneus.

Figure 2

Regions sensitive to the conflict between orthography and phonology (conflicting > nonconflicting conditions). A: Conflict‐sensitive‐regions common to both the spelling and rhyming tasks (presented from the rhyming task masked by the contrast of conflicting > nonconflicting from the spelling task). B: Conflict‐sensitive‐regions in the spelling task masked by the contrast of spelling > rhyming (blue). Activation threshold of P < 0.005 uncorrected is presented. The location of subthreshold activation (P < 0.05 uncorrected) within a mask of rhyming > spelling is marked in pink. C: Conflict‐sensitive‐regions in the rhyming task masked by the contrast of spelling > rhyming (blue) and rhyming > spelling (red). Activation threshold of P < 0.005 uncorrected is presented. Cing, Cingulate gyrus (see Fig. 1 for other regions).