Kim, NamheeGoel, Prem K.Tivarus, Madalina E.Hillier, AshleighBeversdorf, David Q.2014-03-052020-02-192014-03-052020-02-192010-08-17Kim, N., Goel, P. K., Tivarus, M. E., Hillier, A., Beversdorf, D. Q. (2010, August 17). Independent Component Analysis of the Effect of L-dopa on fMRI of Language Processing. PloS One 5(8), 1-10. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.001193310.1371/journal.pone.0011933http://hdl.handle.net/20.500.12517/195Ashleigh Hillier serves on the faculty at UMass Lowell in the Department of Psychology.L-dopa, which is a precursor for dopamine, acts to amplify strong signals, and dampen weak signals as suggested by previous studies. The effect of L-dopa has been demonstrated in language studies, suggesting restriction of the semantic network. In this study, we aimed to examine the effect of L-dopa on language processing with fMRI using Independent Component Analysis (ICA). Two types of language tasks (phonological and semantic categorization tasks) were tested under two drug conditions (placebo and L-dopa) in 16 healthy subjects. Probabilistic ICA (PICA), part of FSL, was implemented to generate Independent Components (IC) for each subject for the four conditions and the ICs were classified into task-relevant source groups by a correlation threshold criterion. Our key findings include: (i) The highly task-relevant brain regions including the Left Inferior Frontal Gyrus (LIFG), Left Fusiform Gyrus (LFUS), Left Parietal lobe (LPAR) and Superior Temporal Gyrus (STG) were activated with both L-dopa and placebo for both tasks, and (ii) as compared to placebo, L-dopa was associated with increased activity in posterior regions, including the superior temporal area (BA 22), and decreased activity in the thalamus (pulvinar) and inferior frontal gyrus (BA 11/47) for both tasks. These results raise the possibility that L-dopa may exert an indirect effect on posterior regions mediated by the thalamus (pulvinar).en-USArticle