Dopaminergic neuromodulation of semantic processing: A 4-T fMRI study with levodopa
Copland, D. A., McMahon, K. L., Silburn, P. A., & de Zubicaray, Greig I. (2009) Dopaminergic neuromodulation of semantic processing: A 4-T fMRI study with levodopa. Cerebral Cortex, 19(11), pp. 2651-2658.
There is emerging evidence that alterations in dopaminergic transmission can influence semantic processing, yet the neural mechanisms involved are unknown. The influence of levodopa (L-DOPA) on semantic priming was investigated in healthy individuals (n=20) using event-related functional magnetic resonance imaging with a randomized, double-blind crossover design. Critical prime-target pairs consisted of a lexical ambiguity prime and 1) a target related to the dominant meaning of the prime (e.g., bank-money), 2) a target related to the subordinate meaning (e.g., fence-sword), or 3) an unrelated target (e.g., ball-desk). Behavioral data showed that both dominant and subordinate meanings were primed on placebo. In contrast, there was preserved priming of dominant meanings and no significant priming of subordinate meanings on L-DOPA, the latter associated with decreased anterior cingulate and dorsal prefrontal cortex activity. Dominant meaning activation on L-DOPA was associated with increased activity in the left rolandic operculum and left middle temporal gyrus. These findings suggest that L-DOPA enhances frequency-based semantic focus via prefrontal and temporal modulation of automatic semantic priming and through engagement of anterior cingulate mechanisms supporting attentional/controlled priming.
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|Item Type:||Journal Article|
|Additional Information:||Cited By :16
Export Date: 17 July 2015
|Keywords:||Brain imaging, Dopamine, FMRI, Language, Lexical ambiguity, Semantic priming|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 2009 The Author|
|Deposited On:||04 Sep 2015 00:10|
|Last Modified:||07 Sep 2015 01:43|
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