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Recent work has suggested that variability in levels of neural activation may be related to behavioral and cognitive performance across a number of domains and may offer information that is not captured by more traditional measures that use the average level of brain activation. We examined the relationship between reading skill in school-aged children and neural activation variability during a functional MRI reading task after taking into account average levels of activity. The reading task involved matching printed and spoken words to pictures of items. Single trial activation estimates were used to calculate the mean and standard deviation of children's responses to print and speech stimuli; multiple regression analyses evaluated the relationship between reading skill and trial-by-trial activation variability. The reliability of observed findings from the discovery sample (n = 44; ages 8-11; 18 female) was then confirmed in an independent sample of children (n = 32; ages 8-11; 14 female). Across the two samples, reading skill was positively related to trial-by-trial variability in the activation response to print in the left inferior frontal gyrus pars triangularis. This relationship held even when accounting for mean levels of activation. This finding suggests that intrasubject variability in trial-by-trial fMRI activation responses to printed words accounts for individual differences in human reading ability that are not fully captured by traditional mean levels of brain activity. Furthermore, this positive relationship between trial-by-trial activation variability and reading skill may provide evidence that neural variability plays a beneficial role during early reading development.SIGNIFICANCE STATEMENT Recent work has suggested that neural activation variability, or moment-to-moment changes in the engagement of brain regions, is related to individual differences in behavioral and cognitive performance across multiple domains. However, differences in neural activation variability have not yet been evaluated in relation to reading skill. In the current study, we analyzed data from two independent groups of children who performed an fMRI task involving reading and listening to words. Across both samples, reading skill was positively related to trial-by-trial variability in activation to print stimuli in the left inferior frontal gyrus pars triangularis, even when accounting for the more conventional measure of mean levels of brain activity. This finding suggests that neural variability could be beneficial in developing readers.

Becoming a skilled reader requires building a functional neurocircuitry for printed-language processing that integrates with spoken-language-processing networks. In this longitudinal study, functional MRI (fMRI) was used to examine convergent activation for printed and spoken language (print-speech coactivation) in selected regions implicated in printed-language processing (the reading network). We found that print-speech coactivation across the left-hemisphere reading network in beginning readers predicted reading achievement 2 years later beyond the effects of brain activity for either modality alone; moreover, coactivation effects accounted for variance in later reading after controlling for initial reading performance. Within the reading network, effects of coactivation were significant in bilateral inferior frontal gyrus (IFG) and left inferior parietal cortex and fusiform gyrus. The contribution of left and right IFG differed, with more coactivation in left IFG predicting better achievement but more coactivation in right IFG predicting poorer achievement. Findings point to the centrality of print-speech convergence in building an efficient reading circuitry in children.

To investigate the neural basis of a common statistical learning mechanism involved in motor sequence learning and decoding, we recorded brain activation from participants during a serial reaction time (SRT) task and a word reading task using functional magnetic resonance imaging. In the SRT task, a manual response was made depending on the location of a visual cue, and the order of the locations was either fixed or random. In the word reading task, visual words were passively presented. In the inferior frontal gyrus pars triangularis (IFGpTr) and the insula, differences in activation between the ordered and random condition in the SRT task and activation to printed words in the word reading task were correlated with the participants' decoding ability. We speculate that extraction of statistically predictable patterns in the IFGpTr and insula contributes to both motor sequence learning and orthographic learning, and therefore predicts individual differences in decoding skill.

Despite anecdotal evidence of relative visuospatial processing strengths in individuals with reading disability (RD), only a few studies have assessed the presence or the extent of these putative strengths. The current study examined the cognitive and neural bases of visuospatial processing abilities in adolescents with RD relative to typically developing (TD) peers. Using both cognitive tasks and functional magnetic resonance imaging (fMRI) we contrasted printed word recognition with non-language visuospatial processing tasks. Behaviorally, lower reading skill was related to a visuospatial processing advantage (shorter latencies and equivalent accuracy) on a geometric figure processing task, similar to findings shown in two published studies. FMRI analyses revealed key group by task interactions in patterns of cortical and subcortical activation, particularly in frontostriatal networks, and in the distributions of right and left hemisphere activation on the two tasks. The results are discussed in terms of a possible neural tradeoff in visuospatial processing in RD.

Reading disability is a brain-based difficulty in acquiring fluent reading skills that affects significant numbers of children. Although neuroanatomical and neurofunctional networks involved in typical and atypical reading are increasingly well characterized, the underlying neurochemical bases of individual differences in reading development are virtually unknown. The current study is the first to examine neurochemistry in children during the critical period in which the neurocircuits that support skilled reading are still developing. In a longitudinal pediatric sample of emergent readers whose reading indicators range on a continuum from impaired to superior, we examined the relationship between individual differences in reading and reading-related skills and concentrations of neurometabolites measured using magnetic resonance spectroscopy. Both continuous and group analyses revealed that choline and glutamate concentrations were negatively correlated with reading and related linguistic measures in phonology and vocabulary (such that higher concentrations were associated with poorer performance). Correlations with behavioral scores obtained 24 months later reveal stability for the relationship between glutamate and reading performance. Implications for neurodevelopmental models of reading and reading disability are discussed, including possible links of choline and glutamate to white matter anomalies and hyperexcitability. These findings point to new directions for research on gene-brain-behavior pathways in human studies of reading disability.

The purpose of the study was to identify structural brain differences in school-age children with residual speech sound errors. Voxel based morphometry was used to compare gray and white matter volumes for 23 children with speech sound errors, ages 8;6-11;11, and 54 typically speaking children matched on age, oral language, and IQ. We hypothesized that regions associated with production and perception of speech sounds would differ between groups. Results indicated greater gray matter volumes for the speech sound error group relative to typically speaking controls in bilateral superior temporal gyrus. There was greater white matter volume in the corpus callosum for the speech sound error group, but less white matter volume in right lateral occipital gyrus. Results may indicate delays in neuronal pruning in critical speech regions or differences in the development of networks for speech perception and production.

Gough and Tunmer's (1986) simple view of reading (SVR) proposed that reading comprehension (RC) is a function of language comprehension (LC) and word recognition/decoding. Braze et al. (2007) presented data suggesting an extension of the SVR in which knowledge of vocabulary (V) affected RC over and above the effects of LC. Tunmer and Chapman (2012) found a similar independent contribution of V to RC when the data were analyzed by hierarchical regression. However, additional analysis by factor analysis and structural equation modeling indicated that the effect of V on RC was, in fact, completely captured by LC itself and there was no need to posit a separate direct effect of V on RC. In the present study, we present new data from young adults with sub-optimal reading skill (N = 286). Latent variable and regression analyses support Gough and Tunmer's original proposal and the conclusions of Tunmer and Chapman that V can be considered a component of LC and not an independent contributor to RC.

For accurate reading comprehension, readers must first learn to map letters to their corresponding speech sounds and meaning, and then they must string the meanings of many words together to form a representation of the text. Furthermore, readers must master the complexities involved in parsing the relevant syntactic and pragmatic information necessary for accurate interpretation. Failure in this process can occur at multiple levels, and cognitive neuroscience has been helpful in identifying the underlying causes of success and failure in reading single words and in reading comprehension. In general, neurobiological studies of skilled reading comprehension indicate a highly overlapping language circuit for single-word reading, reading comprehension, and listening comprehension, with largely quantitative differences in a number of reading- and language-related areas. This article reviews relevant research from studies that have used neuroimaging techniques to study reading with a focus on the relationship between reading skill, single-word reading, and text comprehension.

Using functional magnetic resonance imaging, we investigated multimodal (visual and auditory) semantic and unimodal (visual only) phonological processing in reading disabled (RD) adolescents and non-impaired (NI) control participants. We found reduced activation for RD relative to NI in a number of left-hemisphere reading-related areas across all processing tasks regardless of task type (semantic vs. phonological) or modality (auditory vs. visual modality). Moreover, activation differences in these regions, which included the inferior frontal gyrus, the superior temporal gyrus, and the occipitotemporal region, were largely independent of in-scanner performance in our auditory semantic task. That is, although RD participants and NI participants differed in performance in visually presented conditions, they did not differ significantly in the auditory condition, yet similar patterns of reduced activation were observed in these regions across conditions. These findings indicate a neurobiological marker in RD that is independent of task, modality, or performance. These findings are discussed in the context of current neurobiological models of RD.

Using fMRI, we explored the relationship between phonological awareness (PA), a measure of metaphonological knowledge of the segmental structure of speech, and brain activation patterns during processing of print and speech in young readers from 6 to 10 years of age. Behavioral measures of PA were positively correlated with activation levels for print relative to speech tokens in superior temporal and occipito-temporal regions. Differences between print-elicited activation levels in superior temporal and inferior frontal sites were also correlated with PA measures with the direction of the correlation depending on stimulus type: positive for pronounceable pseudowords and negative for consonant strings. These results support and extend the many indications in the behavioral and neurocognitive literature that PA is a major component of skill in beginning readers and point to a developmental trajectory by which written language engages areas originally shaped by speech for learners on the path toward successful literacy acquisition.

In recent years, significant progress has been made in the study of reading and reading disability with the use of functional neuroimaging techniques. There is substantial converging evidence that skilled word recognition requires the development of a highly integrated cortical system that includes left hemisphere dorsal, ventral, and anterior subsystems. This article highlights key findings regarding the functional role of these regions during skilled reading, the developmental trajectory toward this mature reading circuitry in normally developing children, deviations from this trajectory in populations with reading disabilities, and the ways in which successful reading remediation alters the brain organization for reading. We present one possible interpretation of these findings and report some recent findings from our lab that continue to refine our understanding of the functional properties of each component region and the ways in which these areas interact. The article concludes with a discussion of important areas of inquiry to be addressed in future work.

This article proposes a neurobiological account of reading and reading disability suggesting that for normally developing readers, the dorsal (tempo-parietal) circuit predominates at first, and in conjunction with premotor systems, is associated with analytic processing necessary for learning to integrate orthographic with phonological and lexical-semantic features of printed words. The ventral (occipito-temporal) circuit underlies fluency in word recognition. (Contains references.) (Author/DB)

Converging evidence from a number of neuroimaging studies suggest that fluent word identification in reading is related to the functional integrity of two left hemisphere posterior systems: a temporo-parietal system and a ventral occipito-temporal system. Readers with difficulties demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions. (Contains references.) (Author/CR)

Purpose: To examine neural response to spoken and printed language in children with speech sound errors (SSE). Method: Functional magnetic resonance imaging was used to compare processing of auditorily and visually presented words and pseudowords in 17 children with SSE, ages 8;6[years;months] through 10;10, with 17 matched controls. Results: When processing spoken words and pseudowords, the SSE group showed less activation than typically speaking controls in left middle temporal gyrus. They also showed greater activation than controls in several cortical and subcortical regions (e.g., left superior temporal gyrus, globus pallidus, insula, fusiform, and bilateral parietal regions). In response to printed words and pseudowords, children with SSE had greater activation than controls in regions including bilateral fusiform and anterior cingulate. Some differences were found in both speech and print processing that that may be associated with children with SSE failing to show common patterns of task-induced deactivation and/or attentional resource allocation. Conclusion: Compared with controls, children with SSE appear to rely more on several dorsal speech perception regions and less on ventral speech perception regions. When processing print, numerous regions were observed to be activated more for the SSE group than for controls. Key Words: functional magnetic resonance imaging (fMRI), speech sound errors, speech perception, print processing, Overt misarticulations (e.g., sound substitutions, omissions, and distortions) that persist into elementary school are associated with negative academic, social, and speech-language outcomes (Lewis & Freebairn, 1992; Nathan, Stackhouse, Goulandris, & [...]