Angwin Anthony J, Arnott Wendy L, Copland David A, Haire Miriam P L, Murdoch Bruce E, Silburn Peter A, Chenery Helen J
Centre for Research in Language Processing and Linguistics, The University of Queensland, Brisbane, Australia.
Cortex. 2009 Sep;45(8):950-9. doi: 10.1016/j.cortex.2009.02.012. Epub 2009 Mar 11.
Research suggests that dopamine may exert a neuromodulatory influence on automatic spreading activation within semantic networks. In order to investigate the influence of dopamine depletion on semantic activation in Parkinson's disease (PD), nine patients with PD performed a lexical decision task when on and off levodopa medication. Eleven healthy controls matched to the PD patients in terms of sex, age and education also participated in the study. Both directly related word pairs (e.g., tiger - stripe) and indirectly related word pairs (word pairs related via a mediating word, e.g., chalk - black) were used to measure semantic activation across stimulus onset asynchronies (SOAs) of 270msec, 520msec and 1020msec. Analysis of variance statistics revealed that the activation of directly related and indirectly related targets was slower for the PD group relative to the control group. Within group comparisons revealed further changes to semantic activation in PD patients off medication, with no activation of directly or indirectly related target words evident in PD patients off medication. These results further clarify the nature of dopamine's neuromodulatory influence on semantic activation, and suggest that the nature of altered semantic activation in PD may depend on the magnitude of dopamine depletion.
研究表明，多巴胺可能对语义网络内的自动扩散激活发挥神经调节作用。为了研究多巴胺耗竭对帕金森病（PD）语义激活的影响，9名PD患者在服用左旋多巴药物和未服用时分别进行了词汇判断任务。11名在性别、年龄和教育程度上与PD患者匹配的健康对照者也参与了该研究。直接相关词对（如老虎 - 条纹）和间接相关词对（通过中介词相关的词对，如粉笔 - 黑色）被用于测量在270毫秒、520毫秒和1020毫秒的刺激起始异步（SOA）下的语义激活。方差分析统计显示，相对于对照组，PD组中直接相关和间接相关目标的激活较慢。组内比较显示，未服药的PD患者语义激活有进一步变化，未服药的PD患者中直接或间接相关目标词均无明显激活。这些结果进一步阐明了多巴胺对语义激活的神经调节作用的性质，并表明PD中语义激活改变的性质可能取决于多巴胺耗竭的程度。
