Two Mechanisms for Task Switching in the Prefrontal Cortex
Two Mechanisms for Task Switching in the Prefrontal Cortex
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DOI：
10.1523/jneurosci.2828-08.2009
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发表时间：
2009-04-22
影响因子：
5.3
通讯作者：
Koechlin, Etienne
中科院分区：
文献类型：
--
作者：
Hyafil, Alexandre;Summerfield, Christopher;Koechlin, Etienne
测量任务之间切换的认知和神经后遗症允许一个窗口到执行控制系统的灵活运作。任务转换后反应时间延长（RT）伴随着前扣带皮层（ACC）和背外侧前额叶皮层（dlPFC）的大脑活动增加，但这些区域对任务水平控制的贡献仍然存在争议。在这里，受试者进行了混合空间Stroop/任务切换范式，要求他们响应一致或不一致的空间/语言线索与操纵杆运动。相对于前一次试验，活动任务要么切换要么保持不变。计算开关成本作为当前和以前的审判一致性的函数，我们观察到一般RT增加每个开关试验，和额外的放缓和损害性能时，开关发生在第二个连续的不一致的试验（iI试验）。成像数据显示，这两个开关成本相应的神经伴随物：ACC被激活的任务开关，无论试验类型（包括一致的试验中，任务相关和任务无关的信息不冲突），而尾部dlPFC表现出开关成本是唯一的iI试验。我们认为，行政协调会配置的优先事项与一个新的任务，而dlPFC处理干扰最近活跃的，竞争性的任务集。这些数据有助于文献认为，人类的认知灵活性的好处，从设定新的优先事项，为未来的行动，以及克服干扰，从以前活跃的任务集。
Measuring the cognitive and neural sequelae of switching between tasks permits a window into the flexible functioning of the executive control system. Prolonged reaction times (RTs) after task switches are accompanied by increases in brain activity in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (dlPFC), but the contribution made by these regions to task level control remains controversial. Here, subjects performed a hybrid spatial Stroop/task-switching paradigm, requiring them to respond with a joystick movement to congruent or incongruent spatial/verbal cues. Relative to the previous trial, the active task either switched or remained the same. Calculating switch costs as a function of current and previous trial congruency, we observed both a general RT increase on every switch trial, and additional slowing and impairment to performance when the switch occurred on the second of two successive incongruent trials (iI trials). Imaging data revealed corresponding neural concomitants of these two switch costs: the ACC was activated by task switches regardless of trial type (including congruent trials in which task-relevant and task-irrelevant information did not clash), whereas the caudal dlPFC exhibited a switch cost that was unique to iI trials. We argue that the ACC configures the priorities associated with a new task, whereas the dlPFC tackles interference from recently active, rivalrous task sets. These data contribute to a literature arguing that human cognitive flexibility benefits from the setting of new priorities for future action as well as the overcoming of interference from previously active task sets.