Wylie G R, Javitt D C, Foxe J J
The Cognitive Neurophysiology Laboratory, Program in Cognitive Neuroscience and Schizophrenia, Nathan S. Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
Cereb Cortex. 2006 Mar;16(3):394-404. doi: 10.1093/cercor/bhi118. Epub 2005 May 25.
Subjects switched between tasks that rely on separable "low-level" neural circuits, a motion and a color task. Using functional magnetic resonance imaging, we assessed anticipatory processes within these circuits during preparation to switch between tasks. Once the switch was made, we could then compare activation levels within the circuit associated with the newly relevant task to continuing activity in the circuit associated with the irrelevant task, allowing us to assess both the effectiveness of anticipatory switching mechanisms and the subsequent competition between alternative stimulus-response contingencies. Subjects prepared effectively for the color task, being equally fast and accurate on switch trials as on repeat trials, and this successful preparation was associated with robust preparatory activity within well-known color-processing regions. In contrast, subjects showed considerable behavioral costs when switching to the motion task, evincing a lack of effective preparation, borne out by the fact that motion circuits were silent during the preparatory period.
受试者在依赖可分离的“低级”神经回路的任务之间切换，即一个运动任务和一个颜色任务。我们使用功能磁共振成像，在准备切换任务期间评估这些回路中的预期过程。一旦做出切换，我们就可以将与新相关任务相关的回路中的激活水平与与不相关任务相关的回路中的持续活动进行比较，从而使我们能够评估预期切换机制的有效性以及替代刺激-反应偶然性之间随后的竞争。受试者有效地为颜色任务做好了准备，在切换试验中与重复试验中的速度和准确性相同，并且这种成功的准备与著名的颜色处理区域内强大的准备活动相关。相比之下，受试者在切换到运动任务时表现出相当大的行为成本，表明缺乏有效的准备，这一事实证明在准备期间运动回路处于沉默状态。
