Examining the neural and cognitive processes that underlie reading through naming speed tasks

• Published in: The European journal of neuroscience Vol. 51; no. 11; pp. 2277 - 2298
• Main Authors: Al Dahhan, Noor Z., Kirby, John R., Chen, Ying, Brien, Donald C., Munoz, Douglas P.
• Format: Journal Article
• Language: English
• Published: France Wiley Subscription Services, Inc 01-06-2020
• Subjects: Cognition; Cognitive ability; Eye movements; eye tracking; fMRI; Functional magnetic resonance imaging; Hemispheric laterality; Language; Motion; Naming; naming speed; Neuroimaging; orthography; Phonological processing; Phonological similarity; Phonology; Reading; Sensorimotor system; Speech; Speech production; phonological processing; fMRI; naming speed; eye tracking; orthography
• ISSN: 0953-816X; 1460-9568
• DOI: 10.1111/ejn.14673

We combined fMRI with eye tracking and speech recording to examine the neural and cognitive mechanisms that underlie reading. To simplify the study of the complex processes involved during reading, we used naming speed (NS) tasks (also known as rapid automatized naming or RAN) as a focus for this study, in which average reading right‐handed adults named sets of stimuli (letters or objects) as quickly and accurately as possible. Due to the possibility of spoken output during fMRI studies creating motion artifacts, we employed both an overt session and a covert session. When comparing the two sessions, there were no significant differences in behavioral performance, sensorimotor activation (except for regions involved in the motor aspects of speech production) or activation in regions within the left‐hemisphere‐dominant neural reading network. This established that differences found between the tasks within the reading network were not attributed to speech production motion artifacts or sensorimotor processes. Both behavioral and neuroimaging measures showed that letter naming was a more automatic and efficient task than object naming. Furthermore, specific manipulations to the NS tasks to make the stimuli more visually and/or phonologically similar differentially activated the reading network in the left hemisphere associated with phonological, orthographic and orthographic‐to‐phonological processing, but not articulatory/motor processing related to speech production. These findings further our understanding of the underlying neural processes that support reading by examining how activation within the reading network differs with both task performance and task characteristics.
We combined fMRI and eye tracking with speech recording to examine the mechanisms underlying reading through naming speed tasks. There were no differences between overt and covert sessions, which validate the use of overt naming in fMRI studies and allow for the replication of traditional behavioral studies using overt tasks. Activation differed based on the tasks’ sensitivity to posterior cortical areas in the reading network involved in processing and interpreting orthographic information.