ERIC Number: EJ864494
Record Type: Journal
Publication Date: 2009-Jun
Abstractor: As Provided
Reference Count: 0
Developmental Increase in Top-Down and Bottom-Up Processing in a Phonological Task: An Effective Connectivity, fMRI Study
Bitan, Tali; Cheon, Jimmy; Lu, Dong; Burman, Douglas D.; Booth, James R.
Journal of Cognitive Neuroscience, v21 n6 p1135-1145 Jun 2009
We examined age-related changes in the interactions among brain regions in children performing rhyming judgments on visually presented words. The difficulty of the task was manipulated by including a conflict between task-relevant (phonological) information and task-irrelevant (orthographic) information. The conflicting conditions included pairs of words that rhyme despite having different spelling patterns ("jazz-has"), or words that do not rhyme despite having similar spelling patterns ("pint-mint"). These were contrasted with nonconflicting pairs that have similar orthography and phonology ("dime-lime") or different orthography and phonology ("press-list"). Using fMRI, we examined effective connectivity among five left hemisphere regions of interest: fusiform gyrus (FG), inferior frontal gyrus (IFG), intraparietal sulcus (IPS), lateral temporal cortex (LTC), and medial frontal gyrus (MeFG). Age-related increases were observed in the influence of the IFG and FG on the LTC, but only in conflicting conditions. These results reflect a developmental increase in the convergence of bottom-up and top-down information on the LTC. In older children, top-down control process may selectively enhance the sensitivity of the LTC to bottom-up information from the FG. This may be evident especially in situations that require selective enhancement of task-relevant versus task-irrelevant information. Altogether these results provide a direct evidence for a developmental increase in top-down control processes in language processing. The developmental increase in bottom-up processing may be secondary to the enhancement of top-down processes.
Descriptors: Brain Hemisphere Functions, Phonology, Rhyme, Children, Age Differences, Written Language, Language Processing
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Authoring Institution: N/A