Functional and structural connectivity of reading networks in the adult brain

• Main Author: Su, M. T.
• Other Authors: Clark, C. A. ; Liegeois, F.
• Published: University College London (University of London) 2016
• Subjects: 618.92
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.746308

Language processing draws upon many distributed regions in the brain. Reading in particular is a skill that emerges from the interaction between brain regions involved in phonological and orthographical processing. This project examined the reading network in adults (18-35 years old) with and without developmental dyslexia. Each participant was assessed on a comprehensive battery of standardised neuropsychological tests, which assessed IQ, reading accuracy and comprehension, spelling, phonological processing, working memory, grammatical understanding, motor coordination, and expressive and receptive language skills. In addition, each participant underwent a non-invasive MRI scan, during which structural and functional images were acquired. More specifically, T1-weighted and diffusion-weighted images were acquired to assess structural networks in the brain, whereas a simple reading task and resting-state fMRI were acquired to assess the functional networks involved in reading. Individuals with dyslexia were found to show reduced activation and reduced connectivity in regions typically associated with skilled reading. Moreover, results suggested that they rely on more effortful processing and attentional mechanisms instead to compensate for their reading difficulties. All in all, results indicated that individuals with developmental dyslexia had abnormal functional and structural brain networks related to reading performance, as well as other functions, such as working memory. These findings suggest that for successful reading remediation, it is important to focus on the integration of phonology with orthography, as well as with working memory. Literacy problems such as developmental dyslexia are thus better characterised as a complex disorder with multiple deficits rather than by a single phonological deficit.