Phonological awareness predicts activation patterns for print and speech.
Annals of Dyslexia, June, 2009 Vol. 59, No. 1, Pages 78-97.
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.
Authors: Stephen J. Frost, Nicole Landi, W. Einar Mencl, Rebecca Sandak , Robert K. Fulbright, Eleanor T. Tejada , Leslie Jacobsen, Elena L. Grigorenko, R. Todd Constable, Kenneth R. Pugh.
Effects of Stimulus Difficulty and Repetition on Printed Word Identification: An fMRI Comparison of Nonimpaired and Reading-disabled Adolescent Cohorts
Journal of Cognitive Neuroscience, July, 2008, Vol. 20, No. 7, Pages 1146-1160.
Functional neuroimaging studies indicate that a primary marker of specific reading disability (RD) is reduced activation of left hemisphere (LH) posterior regions during performance of reading tasks. However, the severity of this disruption, and the extent to which these LH systems might be available for reading under any circumstances, is unclear at present. Experiment 1 examined the cortical effects of stimulus manipulations (frequency, imageability, consistency) that have known facilitative effects on reading performance for both nonimpaired (NI) and RD readers. Experiment 2 examined stimulus repetition, another facilitative variable, in an additional sample of adolescent NI and RD readers. For NI readers, factors that made words easier to process were associated with relatively reduced activation. For RD readers, facilitative factors resulted in increased activation in these same reading-related sites, suggesting that the LH reading circuitry in adolescent RD is poorly trained but not wholly disrupted.
Authors: Kenneth R. Pugh, Stephen J. Frost, Rebecca Sandak, Nicole Landi, Jay G. Rueckl, R. Todd Constable, Mark S. Seidenberg, Robert K. Fulbright, Leonard Katz, and W. Einar Mencl
Examining reading development and reading disability in English language learners: Potential contributions from functional neuroimaging.
[ Neuroimaging studies have suggested that across different written languages, skilled reading behavior is supported by similar, largely left hemisphere (LH), networks. In addition, recent studies of reading disability (RD) in monolingual readers, conducted in several languages, suggest a common neurobiological signature for this syndrome (disruption of LH posterior regions that support fluent reading). Thus, at the neurobiological level of analysis, reading and its disorders appear to be more similar than dissimilar across languages. In this article, we consider the neurobiology of reading development and RD in English language learners (ELL). There is some evidence suggesting that fluent bilingual readers tend to engage primarily overlapping circuits for both L1 and L2. There is, however, a paucity of neurobiological research on both reading development and RD in this population. Using the existing research on RD as a starting point, we consider in this article how developmental neuroimaging techniques might be applied to (1) help identify RD readers in the ELL populations, and (2) provide neurobiological outcome measures to help evaluate the efficacy of different approaches to the teaching of reading in English. ]
Authors: Kenneth R. Pugh, Rebecca
Sandak, Stephen J. Frost, Dina Moore, and W. Einar Mencl
Development of left occipitotemporal systems for skilled reading in children after a phonologically-based intervention.
[ A range of neurobiological investigations shows a failure of left hemisphere posterior brain systems to function properly during reading in children and adults with reading disabilities. Such evidence of a disruption in the normal reading pathways provides a neurobiological target for reading interventions. In this study, we hypothesized that the provision of an evidence-based, phonologically mediated reading intervention would improve reading fluency and the development of the fast-paced occipitotemporal systems serving skilled reading. ]
Authors: Bennett A. Shaywitz, Sally
E. Shaywitz, Benita A. Blachman, Kenneth R. Pugh, Robert K. Fulbright,
Pawel Skudlarski, W. Einar Mencl, R. Todd Constable, John M. Holahan,
Karen E. Marchione, Jack M. Fletcher, G. Reid Lyon, and John C.
Neurobiological studies of reading and reading disability.
[ Evidence from neuroimaging studies, including our own, suggest that skilled word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system appears to be functionally disrupted in developmental dyslexia. Relative to nonimpaired readers, reading-disabled individuals demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers, the dorsal 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 circuit constitutes a fast, late-developing, word form system, which underlies fluency in word recognition. ]
Authors: Kenneth R. Pugh, W. Einar
Mencl, Annette R. Jenner,
Leonard Katz, Stephen J. Frost, Jun Ren Lee,
Sally E. Shaywitz, Bennett A. Shaywitz
Neuroimaging studies of reading development and reading disability.
[ Converging evidence from a number of neuroimaging studies, including our own, 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. These posterior systems are functioanlly disrupted in developmental dyslexia. Reading disable, relative to nonimpaired, readers deomnstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the temporo-parietal system predominates at first, and is associated with aspects of processing critical in learning to integrate orthography with phonological and lexical-semantic features of printed words. The occipito-temporal system, by contrast, constitues a fast, late-developing, word-identification system that underlies fluent word recognition in skilled readers. ]
Authors: Kenneth R. Pugh, W. Einar Mencl, Annette R. Jenner, Jun Ren Lee,
Leonard Katz, Stephen J. Frost,
Sally E. Shaywitz, Bennett A. Shaywitz
An event-related neuroimaging study distinguishing form and content in sentence processing.
[ Two coordinated experiments using functional Magnetic Resonance Imaging (fMRI) investigated whether the brain represents language form (grammatical structure) separately from its meaning content (semantics). While in the scanner, 14 young, unimpaired adults listened to simple sentences that were either nonanomalous or contained a grammatical error (for example, *Trees can grew.), or a semantic anomaly (for example, *Trees can eat.). A same/different tone pitch judgment task provided a baseline that isolated brain activity associated with linguistic processing from background activity generated by attention to the task and analysis of the auditory input. Sites selectively activated by sentence processing were found in both hemispheres in inferior frontal, middle, and superior frontal, superior temporal, and temporo-parietal regions. Effects of syntactic and semantic anomalies were differentiated by some nonoverlapping areas of activation: Syntactic anomaly triggered significantly increased activity in and around Broca's area, whereas semantic anomaly activated several other sites anteriorly and posteriorly, among them Wernicke's area. These dissociations occurred when listeners were not required to attend to the anomaly. The results confirm that linguistic operations in sentence processing can be isolated from nonlinguistic operations and support the hypothesis of a specialization for syntactic processing. ]
Authors: W. Ni, R. T. Constable,
W. E. Mencl and K. R. Pugh, R. K. Fulbright, S. E. Shaywitz, B.
A. Shaywitz, and J. C. Gore, D. Shankweiler
Functional neuroimaging studies of reading and reading disability (Developmental dyslexia).
[ Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipitotemporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers. ]
Authors: Kenneth R. Pugh, W. Einar
Mencl, Annette R. Jenner, Jun Ren Lee,
Leonard Katz, Stephen J. Frost, Sally E. Shaywitz, Bennett A. Shaywitz
The angular gyrus in developmental dyslexia: Task-specific differences in functional connectivity within posterior cortex.
[ Converging evidence from neuroimaging studies of developmental dyslexia reveals dysfunction at posterior brain regions centered in and around the angular gyrus in the left hemisphere. We examined functional connectivity (covariance) between the angular gyrus and related occipital and temporal lobe sites, across a series of print tasks that systematically varied demands on phonological assembly. Results indicate that for dyslexic readers a disruption in functional connectivity in the language-dominant left hemisphere is confined to those tasks that make explicit demands on assembly. In contrast, on print tasks that do not require phonological assembly, functional connectivity is strong for both dyslexic and nonimpaired readers. The findings support the view that neurobiological anomalies in developmental dyslexia are largely confined to the phonologicalprocessing domain. In addition, the findings suggest that right hemisphere posterior regions serve a compensatory role in mediating phonological performance in dyslexic readers. ]
Authors: Kenneth R. Pugh, W. Einar
Mencl, Bennett A. Shaywitz, Sally E. Shaywitz,
Robert K. Fulbright, R. Todd Constable, Pawel Skudlarski, Karen E. Marchione,
Annette R. Jenner, Jack M. Fletcher, Alvin M. Liberman,
Donald P. Shankweiler, Leonard Katz, Cheryl Lacadie, and John C. Gore
Predicting reading performance from neuroimaging profiles: The cerebral basis of phonological effects in printed word identification.
[ This study linked 2 experimental paradigms for the analytic study of reading that heretofore have been used separately. Measures on a lexical decision task designed to isolate phonological effects in the identifieadon of printed words were examined in young adults. The results were related to previously obtained measures of brain activation patterns for these participants derived from functional magnetic resonance imaging (fMRI). The fM1LI measures were taken as the participants performed tasks that were designed to isolate orthographic, phonological, and lexical-semantic processes in reading. Individual differences in the magnitude of phonological effects in word recognition, as indicated by spelling-to-sound regularity effects on lexical decision latencies and by sensitivity to stimulus length effects, were strongly related to differences in the degree of hemispheric lateralization in 2 cortical regions. ]
Authors: Kenneth R. Pugh, Donald
P. Shankweiler, Leonard Katz, Bennett A. Shaywitz, Sally E. Shaywitz,
Jack M. Fletcher, Pawel Skudlarski, Robert K. Fulbright, R. Todd
Constable, Richard A. Bronen, Cheryl Lacadie, and John C. Gore