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Talk; brain

Thursday stream 1 Session 09.00 - 11.10 Length 25 minutes

Picture naming and reading in dyslexia: a brain imaging study

Eamon McCrory

Institute of Cognitive Neuroscience, University College London e.mccrory@ucl.ac.uk

Abstract

Previous imaging studies have shown that a posterior inferior region of the left temporal lobe (BA37) displays significantly reduced activation in dyslexic readers (Shaywitz et al, 1998; Brunswick et al, 1999). In the normal population this area is reliably activated by both reading and picture naming, indicating a key role in phonological retrieval. The current study employed PET (Positron Emission Tomography) to establish whether BA37 also showed reduced activation by dyslexic adults during a task of picture naming. 8 Dyslexic and 10 Control participants were recruited. Both groups received a comprehensive battery of behavioural tasks including measures of reading and spelling (WRAT), intelligence (WAIS III), and picture and word reading speed. The same picture and word reading tasks were later presented to the subjects in the scanner in addition to a baseline condition to control for basic articulation and visual processing. Between group differences in brain activation are discussed in relation to the phonological deficit hypothesis of dyslexia. In particular a specific deficit in phonological retrieval is explored.