title: Weaker top-down modulation from the left inferior frontal gyrus in children.
abstract: Previous studies have shown that developmental changes in the structure and function of prefrontal regions can continue throughout childhood and adolescence. Our recent results suggested a role for the left inferior frontal cortex in modulating task-dependent shifts in effective connectivity when adults focus on orthographic versus phonological aspects of presented words. Specifically, the top-down influence of the inferior frontal cortex determined whether incoming word-form information from the fusiform gyrus would have a greater impact on the parietal areas involved in orthographic processing or temporal areas involved in phonological processing (Bitan, T., Booth, J.R., Choy, J., Burman, D.D., Gitelman, D.R. and Mesulam, M.-M., 2005. Shifts of Effective Connectivity within a Language Network during Rhyming and Spelling. J. Neurosci. 25, 5397-5403.). In the current study, we find that children displayed an identical pattern of task-dependent functional activations within this network. In comparison to adults, however, children had significantly weaker top-down modulatory influences emanating from the inferior frontal area. Adult language processing may thus involve greater top-down cognitive control compared to children, resulting in less interference from task-irrelevant information.
authors.affiliation: Northwestern University, Evanston, Illinois 60208-3500, USA. t-bitan@northwestern.edu
authors.forename: Tali
authors.initials: T
authors.lastname: Bitan
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Burman
authors.forename: Dong
authors.initials: D
authors.lastname: Lu
authors.forename: Nadia E
authors.initials: NE
authors.lastname: Cone
authors.forename: Darren R
authors.initials: DR
authors.lastname: Gitelman
authors.forename: M-Marsel
authors.initials: MM
authors.lastname: Mesulam
authors.forename: James R
authors.initials: JR
authors.lastname: Booth
mesh_terms: D000328:Adult; D002648:Child; D005260:Female; D005625:Frontal Lobe / Q000254:growth & development / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011932:Reading; D014796:Visual Perception / Q000502:physiology