Brain Activation during Sentence Comprehension among Good and Poor Readers

A. Meyler,D. Lee,T. A. Keller,F. Hoeft,J. D. E. Gabrieli,V. L. Cherkassky,S. Whitfield-Gabrieli,M. A. Just

doi:10.1093/cercor/bhm006

Abstract

This study sought to increase current understanding of the neuropsychological basis of poor reading ability by using fMRI to examine brain activation during a visual sentence comprehension task among good and poor readers in the third (n = 32) and fifth (n = 35) grades. Reading ability, age, and the combination of both factors made unique contributions to cortical activation. The main finding was of parietotemporal underactivation (less activation than controls) among poor readers at the 2 grade levels. A positive linear relationship (spanning both the poor and good readers) was found between reading ability and activation in the left posterior middle temporal and postcentral gyri and in the right inferior parietal lobule such that activation increased with reading ability. Different developmental trajectories characterized good and poor readers in the left angular gyrus: activation increased with age among good readers, a change that failed to occur among poor readers. The parietotemporal cortex is discussed in terms of its role in reading acquisition, with the left angular gyrus playing a key role. It is proposed that the functioning of the cortical network underlying reading is dependent on a combination of interacting factors, including physiological maturation, neural integrity, skill level, and the nature of the task.

Highlights

The central aim of this study was to examine brain activation during visual sentence comprehension among poor readers. This subject is of interest because it is not yet known how poor readers’ brains respond when comprehending text. This issue was explored among children with reading problems of varying degrees of severity, enabling us to address the question of continuity in the relationship between poor reading ability and brain function
There were no areas in which poor readers exhibited greater activation than good readers, as indicated by the absence of significant negative partial correlations between reading ability and brain activation
Scatter around the regression line was greater in the left middle temporal gyrus among poor readers, with fifth grade children tending to activate less than third grade children at a given reading level

Summary

Introduction

The central aim of this study was to examine brain activation during visual sentence comprehension among poor readers. This subject is of interest because it is not yet known how poor readers’ brains respond when comprehending text. Developmentally driven physiological changes, such as increased left lateralization for language, may contribute to a different neural manifestation of reading problems at different ages. To examine this issue, the study assessed the brain activity of poor readers in the third and the fifth grades, in comparison to good readers

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