Davidson M C, Cutrell E B, Marrocco R T
Institute of Neuroscience, University of Oregon, Eugene 97403-1254, USA.
Psychopharmacology (Berl). 1999 Feb;142(1):1-8. doi: 10.1007/s002130050855.
The cholinergic agonist nicotine facilitates visuospatial attention shifting, but the role of muscarinic cholinergic drugs in this behavior is unclear. In order to establish the generality of cholinergic action in attention shifting, we administered the muscarinic antagonist scopolamine to two rhesus monkeys trained to perform a cued target detection (Posner) task. In this task, monkeys signaled the detection of a peripheral visual target by releasing a switch and their reaction times were measured. The location of the target's appearance was preceded by a cue that was either valid (target and cue in the same spatial location), invalid (target and cue to opposite hemifields), spatially uninformative (cues in both hemifields, target to one hemifield), or omitted altogether. Scopolamine produced a dose-dependent increase in all reaction times and a decrease in accuracy. The slowing was most prominent for valid cues in either visual field. However, slowing did not occur in trials whose cues lacked spatial information, or in tasks in which attention was directed to events at the fixation point, whether or not peripheral distractors were present. These results provide additional support for the hypothesis that acetylcholine plays a key role in reflexive attention shifting to peripheral visual targets.
胆碱能激动剂尼古丁有助于视觉空间注意力转移，但毒蕈碱型胆碱能药物在此行为中的作用尚不清楚。为了确定胆碱能作用在注意力转移中的普遍性，我们给两只经过训练以执行线索化目标检测（波斯纳）任务的恒河猴施用了毒蕈碱拮抗剂东莨菪碱。在这项任务中，猴子通过松开开关来表明检测到外周视觉目标，并测量它们的反应时间。目标出现的位置之前会有一个线索，该线索要么是有效的（目标和线索在同一空间位置）、无效的（目标和线索在相对的半视野）、空间上无信息的（两个半视野都有线索，目标在一个半视野），要么完全省略。东莨菪碱使所有反应时间呈剂量依赖性增加，准确性降低。在任一视野中，有效线索的减慢最为明显。然而，在线索缺乏空间信息的试验中，或者在注意力指向注视点处事件的任务中，无论是否存在外周干扰物，都没有出现减慢。这些结果为乙酰胆碱在向外周视觉目标的反射性注意力转移中起关键作用这一假设提供了额外支持。
