Differentiating core and co-opted mechanisms in calculation: The neuroimaging of calculation in aphasia

Benn, Y., Wilkinson, I. D., Zheng, Y. ORCID: https://orcid.org/0000-0001-7472-6427, Kadosh, K. C., Romanowski, C. A.J., Siegal, M. and Varley, R. (2013) Differentiating core and co-opted mechanisms in calculation: The neuroimaging of calculation in aphasia. Brain and Cognition, 82 (3). pp. 254-264. ISSN 0278-2626 doi: 10.1016/j.bandc.2013.04.012

Abstract/Summary

The role of language in exact calculation is the subject of debate. Some behavioral and functional neuroimaging investigations of healthy participants suggest that calculation requires language resources. However, there are also reports of individuals with severe aphasic language impairment who retain calculation ability. One possibility in resolving these discordant findings is that the neural basis of calculation has undergone significant reorganization in aphasic calculators. Using fMRI, we examined brain activations associated with exact addition and subtraction in two patients with severe agrammatic aphasia and retained calculation ability. Behavior and brain activations during two-digit addition and subtraction were compared to those of a group of 11 healthy, age-matched controls. Behavioral results confirmed that both patients retained calculation ability. Imaging findings revealed individual differences in processing, but also a similar activation pattern across patients and controls in bilateral parietal cortices. Patients differed from controls in small areas of increased activation in peri-lesional regions, a shift from left fronto-temporal activation to the contralateral region, and increased activations in bilateral superior parietal regions. Our results suggest that bilateral parietal cortex represents the core of the calculation network and, while healthy controls may recruit language resources to support calculation, these mechanisms are not mandatory in adult cognition.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/33494
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Biological Sciences > Department of Bio-Engineering
Uncontrolled Keywords	fMRI; Language; Calculation; Parietal cortex; Aphasia
Publisher	Elsevier
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