Centre for Rural and Remote Mental Health, University of Newcastle, Australia.
Int J Neuropsychopharmacol. 2009 Nov;12(10):1307-17. doi: 10.1017/S146114570999068X. Epub 2009 Oct 1.
Acetylcholine plays a major role in mediating attention processes. We investigated the muscarinic antagonist effect of scopolamine on functional neuro-anatomy of attention and cognition. We assessed 12 healthy volunteers while performing the Attention Network Task on 0.4 mg scopolamine and placebo in a single-blind randomized trial in a 1.5 T magnetic resonance scanner. Neurocognitive measures included verbal learning, verbal memory, verbal fluency, trail making, digit span, a continuous performance task and a planning task (Tower of London). When compared to placebo, scopolamine increased reaction times for conflicting stimulus processing, together with decreasing brain activation in the anterior cingulate cortex (a brain region involved in conflict processing) suggestive of a muscarinic antagonist effect on executive control of attention. Contrary to the notion of a predominantly right-hemispheric lateralization of cognitive processes associated with orienting attention, scopolamine reduced brain activity in left superior and left middle frontal brain areas. Our neuropsychological test data revealed a selective effect of scopolamine on verbal learning and memory while other cognitive domains, such as planning and working memory, were unaffected. These findings are consistent with muscarinic modulation of dopaminergic neurotransmission in frontal attention networks when processing conflicting information.
乙酰胆碱在介导注意力过程中起着重要作用。我们研究了东莨菪碱对注意力和认知功能的神经解剖学的毒蕈碱拮抗作用。我们在 1.5T 磁共振扫描仪中对 12 名健康志愿者进行了单盲随机试验，评估他们在 0.4mg 东莨菪碱和安慰剂条件下执行注意网络任务的情况。神经认知测量包括言语学习、言语记忆、言语流畅性、连线测试、数字跨度、连续性能任务和计划任务（伦敦塔）。与安慰剂相比，东莨菪碱增加了对冲突刺激处理的反应时间，同时减少了前扣带皮层（涉及冲突处理的大脑区域）的大脑激活，表明对注意力的执行控制具有毒蕈碱拮抗作用。与与定向注意力相关的认知过程主要偏右侧的观念相反，东莨菪碱减少了左额上和左额中脑区的大脑活动。我们的神经心理学测试数据显示，东莨菪碱对言语学习和记忆有选择性影响，而其他认知领域，如计划和工作记忆，不受影响。这些发现与处理冲突信息时，前额注意网络中的多巴胺能神经传递的毒蕈碱调节一致。
