Article/Report  |   June 2007
The Influence of Semantic Processing on Phonological Decisions in Children and Adults: A Magnetoencephalography (MEG) Study
 
Author Notes
  • Contact author: Maria Mody, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Building 149 Thirteenth Street, Room 2301, Charlestown, MA 02129. E-mail: maria@nmr.mgh.harvard.edu.
Article Information
Development / Special Populations / Genetic & Congenital Disorders / Normal Language Processing / Speech, Voice & Prosody / Language
Article/Report   |   June 2007
The Influence of Semantic Processing on Phonological Decisions in Children and Adults: A Magnetoencephalography (MEG) Study
Journal of Speech, Language, and Hearing Research, June 2007, Vol. 50, 716-731. doi:10.1044/1092-4388(2007/050)
History: Received November 9, 2005 , Revised May 7, 2006 , Accepted August 22, 2006
 
Journal of Speech, Language, and Hearing Research, June 2007, Vol. 50, 716-731. doi:10.1044/1092-4388(2007/050)
History: Received November 9, 2005; Revised May 7, 2006; Accepted August 22, 2006
Web of Science® Times Cited: 12

Purpose: To examine the behavioral effects and neural activation patterns associated with implicit semantic processing influences on phonological judgments during reading in children and adults.

Method: Whole-head magnetoencephalography (MEG) recordings were obtained from 2 groups, children (9–13 years) and adults, performing a homophone judgment task. The stimuli consisted of pairs of sequentially presented written words that were either homophones, synonym foils, or unrelated control words.

Results: The difference in the time taken to respond to synonym pairs relative to control pairs of stimuli, called the semantic interference effect (SIE), was, on average, 24 ms for adults and 86 ms for children. Source analysis of the MEG data using minimum-norm estimation (MNE) yielded less activation in the adults for the synonym condition compared with the control condition in right anterior temporal and inferior frontal cortex 300–500 ms after the onset of the 2nd word in a pair, suggestive of semantic priming as well as inhibition of the SIE. A similar priming effect was observed for the children in left-anterior temporal cortex.

Conclusion: The observed group differences in the magnitude of the SIE and brain activation patterns may reflect developmental differences in the effects of semantic information on phonological decisions during word processing.

Acknowledgments
This research was supported by Grant DC-00159 from the National Institutes of Health (NIH), awarded to Maria Mody, and in part by the National Center for Research Resources (Grant P41RR14075) and the Mental Illness and Neuroscience Discovery Institute. Daniel T. Wehner was supported, in part, by Training Grant DC00038 from the National Institute on Deafness and Other Communication Disorders, awarded to the Speech and Hearing Bioscience and Technology Program. Seppo Ahlfors was supported by Grant RG-01-0294 from the Whitaker Foundation. We thank Susan Mosher, Matti Hämäläinen, and Mark Vangel for various aspects of data collection, analysis, and statistics.
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