Functional and morphometric brain dissociation between dyslexia and reading ability

Fumiko Hoeft, Ann Meyler, Arvel Hernandez, Connie Juel, Heather Taylor-Hill, Jennifer L. Martindale, Glenn McMillon, Galena Kolchugina, Jessica M. Black, Afrooz Faizi, Gayle K. Deutsch, Wai Ting Siok, Allan L. Reiss, Susan Whitfield-Gabrieli, John D.E. Gabrieli

Research output: Journal article publicationJournal articleAcademic researchpeer-review

346 Citations (Scopus)

Abstract

In functional neuroimaging studies, individuals with dyslexia frequently exhibit both hypoactivation, often in the left parietotemporal cortex, and hyperactivation, often in the left inferior frontal cortex, but there has been no evidence to suggest how to interpret the differential relations of hypoactivation and hyperactivation to dyslexia. To address this question, we measured brain activation by functional MRI during visual word rhyme judgment compared with visual cross-hair fixation rest, and we measured gray matter morphology by voxel-based morphometry in dyslexic adolescents in comparison with (i) an age-matched group, and (ii) a reading-matched group younger than the dyslexic group but equal to the dyslexic group in reading performance. Relative to the age-matched group (n = 19; mean 14.4 years), the dyslexic group (n = 19; mean 14.4 years) exhibited hypoactivation in left parietal and bilateral fusiform cortices and hyperactivation in left inferior and middle frontal gyri, caudate, and thalamus. Relative to the reading-matched group (n = 12; mean 9.8 years), the dyslexic group (n = 12; mean 14.5 years) also exhibited hypoactivation in left parietal and fusiform regions but equal activation in all four areas that had exhibited hyperactivation relative to age-matched controls as well. In regions that exhibited atypical activation in the dyslexic group, only the left parietal region exhibited reduced gray matter volume relative to both control groups. Thus, areas of hyperactivation in dyslexia reflected processes related to the level of current reading ability independent of dyslexia. In contrast, areas of hypoactivation in dyslexia reflected functional atypicalities related to dyslexia itself, independent of current reading ability, and related to atypical brain morphology in dyslexia.

Original languageEnglish
Pages (from-to)4234-4239
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number10
DOIs
Publication statusPublished - 6 Mar 2007
Externally publishedYes

Keywords

  • Compensation
  • Functional MRI
  • Inferior frontal region
  • Inferior parietal lobule
  • Voxel-based morphometry

ASJC Scopus subject areas

  • General

Fingerprint

Dive into the research topics of 'Functional and morphometric brain dissociation between dyslexia and reading ability'. Together they form a unique fingerprint.

Cite this