The neural circuits of number and letter copying: an fNIRS study

Artemenko, C., Coldea, A., Soltanlou, M., Dresler, T., Nuerk, H.-C. and Ehlis, A.-C. (2018) The neural circuits of number and letter copying: an fNIRS study. Experimental Brain Research, 236(4), pp. 1129-1138. (doi: 10.1007/s00221-018-5204-8) (PMID:29445828)

Abstract

In our daily lives, we are constantly exposed to numbers and letters. However, it is still under debate how letters and numbers are processed in the brain, while information on this topic would allow for a more comprehensive understanding of, for example, known influences of language on numerical cognition or neural circuits shared by numerical cognition and language processing. Some findings provide evidence for a double dissociation between numbers and letters, with numbers being represented in the right and letters in the left hemisphere, while the opposing view suggests a shared neural network. Since processing may depend on the task, we address the reported inconsistencies in a very basic symbol copying task using functional near-infrared spectroscopy (fNIRS). fNIRS data revealed that both number and letter copying rely on the bilateral middle and left inferior frontal gyri. Only numbers elicited additional activation in the bilateral parietal cortex and in the left superior temporal gyrus. However, no cortical activation difference was observed between copying numbers and letters, and there was Bayesian evidence for common activation in the middle frontal gyri and superior parietal lobules. Therefore, we conclude that basic number and letter processing are based on a largely shared cortical network, at least in a simple task such as copying symbols. This suggests that copying can be used as a control condition for more complex tasks in neuroimaging studies without subtracting stimuli-specific activation.

• Item Type: Articles
• Additional Information: This research was supported by the LEAD Graduate School & Research Network (GSC1028), which is funded within the framework of the Excellence Initiative of the German federal and state governments. This research was further funded by a Grant from the Science Campus Tübingen, project 8.4 to HCN supporting MS. MS was also supported by the DFG Grant (NU 265/3-1) to HCN. ACE was partly supported by the IZKF Tübingen (Junior Research Group, Grant 2115-0-0).
• Keywords: Copying task, Letter processing, Number processing, fNIRS
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Coldea, Miss Andra
• Authors: Artemenko, C., Coldea, A., Soltanlou, M., Dresler, T., Nuerk, H.-C., and Ehlis, A.-C.
• College/School: College of Science and Engineering > School of Psychology
• Journal Name: Experimental Brain Research
• Publisher: Springer
• ISSN: 0014-4819
• ISSN (Online): 1432-1106
• Published Online: 14 February 2018
• Copyright Holders: Copyright © 2018 Springer-Verlag GmbH Germany, part of Springer Nature
• First Published: First published in Experimental Brain Research 236(4):1129-1138
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher