Individual differences in crossmodal brain activity predict arcuate fasciculus connectivity in developing readers

• Published in: Journal of cognitive neuroscience Vol. 26; no. 7; p. 1331
• Main Authors: Gullick, Margaret M, Booth, James R
• Format: Journal Article
• Language: English
• Published: United States 01-07-2014
• Subjects: Acoustic Stimulation; Adolescent; Auditory Perception - physiology; Brain - blood supply; Brain - physiology; Brain Mapping; Child; Female; Functional Laterality; Humans; Image Processing, Computer-Assisted; Individuality; Magnetic Resonance Imaging; Male; Oxygen - blood; Perforant Pathway - blood supply; Perforant Pathway - physiology; Photic Stimulation; Predictive Value of Tests; Reading; Visual Perception; Vocabulary
• ISSN: 1530-8898
• DOI: 10.1162/jocn_a_00581

Crossmodal integration of auditory and visual information, such as phonemes and graphemes, is a critical skill for fluent reading. Previous work has demonstrated that white matter connectivity along the arcuate fasciculus (AF) is predicted by reading skill and that crossmodal processing particularly activates the posterior STS (pSTS). However, the relationship between this crossmodal activation and white matter integrity has not been previously reported. We investigated the interrelationship of crossmodal integration, both in terms of behavioral performance and pSTS activity, with AF tract coherence using a rhyme judgment task in a group of 47 children with a range of reading abilities. We demonstrate that both response accuracy and pSTS activity for crossmodal (auditory-visual) rhyme judgments was predictive of fractional anisotropy along the left AF. Unimodal (auditory-only or visual-only) pSTS activity was not significantly related to AF connectivity. Furthermore, activity in other reading-related ROIs did not show the same AV-only AF coherence relationship, and AV pSTS activity was not related to connectivity along other language-related tracts. This study is the first to directly show that crossmodal brain activity is specifically related to connectivity in the AF, supporting its role in phoneme-grapheme integration ability. More generally, this study helps to define an interdependent neural network for reading-related integration.