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Parkinson’s Disease
Volume 2011, Article ID 157072, 9 pages
http://dx.doi.org/10.4061/2011/157072
Research Article

The Influence of Dopamine on Automatic and Controlled Semantic Activation in Parkinson's Disease

1School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD 4072, Australia
2Centre for Clinical Research, University of Queensland, Brisbane, QLD 4029, Australia
3Faculty of Health Sciences, University of Queensland, Brisbane, QLD 4029, Australia
4School of Medicine, University of Queensland, Brisbane, QLD 4072, Australia

Received 12 April 2011; Revised 15 September 2011; Accepted 26 September 2011

Academic Editor: Harrison N. Jones

Copyright © 2011 Wendy L. Arnott et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Two semantic priming tasks, designed to isolate automatic and controlled semantic activation, were utilized to investigate the impact of dopamine depletion on semantic processing in Parkinson's disease (PD). Seven people with PD (tested whilst on and off levodopa medication) and seven healthy adults participated in the study. The healthy adult participants demonstrated intact automatic and controlled semantic activation. Aberrant controlled semantic activation was observed in the PD group on levodopa; however, automatic semantic activation was still evident. In contrast, automatic semantic activation was not evident in the PD group off levodopa. These results further clarify the impact of PD on semantic processing, demonstrating that dopamine depletion can cause disturbances in both automatic and controlled semantic activation.