Gibbs S E B, D'Esposito M
Henry H. Wheeler Jr. Brain Imaging Center, Helen Wills Neuroscience Institute and Department of Psychology, University of California, Berkeley, 132 Barker Hall, Berkeley, CA 94720-1650, USA.
Neuroscience. 2006 Apr 28;139(1):359-71. doi: 10.1016/j.neuroscience.2005.11.055. Epub 2006 Feb 3.
Working memory is an important cognitive process dependent on a network of prefrontal and posterior cortical regions. In this study we tested the effects of the mixed D1-D2 dopamine receptor agonist pergolide on component processes of human working memory using functional magnetic resonance imaging (fMRI). An event-related trial design allowed separation of the effects on encoding, maintenance, and retrieval processes. Subjects were tested with spatial and object memoranda to investigate modality-specific effects of dopaminergic stimulation. We also measured baseline working memory capacity as previous studies have shown that effects of dopamine agonists vary with working memory span. Pergolide improved reaction time for high-span subjects and impaired reaction time for low-span subjects. This span-dependent change in behavior was accompanied by span-dependent changes in delay-related activity in the premotor cortex. We also found evidence for modality-specific effects of pergolide only during the response period. Pergolide increased activity for spatial memoranda and decreased activity for object memoranda in task-related regions including the prefrontal and parietal cortices.
工作记忆是一种重要的认知过程，依赖于前额叶和后皮质区域的网络。在本研究中，我们使用功能磁共振成像（fMRI）测试了混合D1 - D2多巴胺受体激动剂培高利特对人类工作记忆组成过程的影响。事件相关试验设计允许分离对编码、维持和检索过程的影响。使用空间和物体记忆对受试者进行测试，以研究多巴胺能刺激的模态特异性效应。我们还测量了基线工作记忆容量，因为先前的研究表明多巴胺激动剂的效应随工作记忆跨度而变化。培高利特改善了高跨度受试者的反应时间，并损害了低跨度受试者的反应时间。这种行为上与跨度相关的变化伴随着运动前皮质中与延迟相关活动的跨度依赖性变化。我们还发现仅在反应期有培高利特的模态特异性效应的证据。在包括前额叶和顶叶皮质在内的与任务相关区域，培高利特增加了对空间记忆的活动，并降低了对物体记忆的活动。
