title: Effects of stimulus difficulty and repetition on printed word identification: an fMRI comparison of nonimpaired and reading-disabled adolescent cohorts.
abstract: 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.affiliation: Haskins Laboratories, New Haven, CT 06511, USA. pugh@haskins.yale.edu
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Pugh
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Frost
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sandak
authors.forename: Nicole
authors.initials: N
authors.lastname: Landi
authors.forename: Jay G
authors.initials: JG
authors.lastname: Rueckl
authors.forename: R Todd
authors.initials: RT
authors.lastname: Constable
authors.forename: Mark S
authors.initials: MS
authors.lastname: Seidenberg
authors.forename: Robert K
authors.initials: RK
authors.lastname: Fulbright
authors.forename: Leonard
authors.initials: L
authors.lastname: Katz
authors.forename: W Einar
authors.initials: WE
authors.lastname: Mencl
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply* / Q000473:pathology / Q000503:physiopathology; D002648:Child; D015331:Cohort Studies; D004410:Dyslexia / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007062:Identification, Psychological; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D014825:Vocabulary
chemical_list: D010100:Oxygen