The function and organization of lateral prefrontal cortex: a test of competing hypotheses.
The function and organization of lateral prefrontal cortex: a test of competing hypotheses.
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DOI：
10.1371/journal.pone.0030284
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Braver TS
中科院分区：
文献类型：
--
作者：
Reynolds JR;O'Reilly RC;Cohen JD;Braver TS
本实验验证了关于外侧前额叶皮质(PFC)功能和组织的三种假说。第一种解释(信息级联假说)认为，外侧PFC的前后组织是基于线索刺激降低动作选择过程中不确定性的时机。第二种解释(抽象水平假说)认为，任务目标的抽象程度决定了外侧PFC的前后组织结构。目前的研究首先调查了这两个假说，并确定了横向PFC的几个区域，这些区域被信息级联和抽象水平账户预测为活跃的。然而，实验条件下的激活模式与两种理论解释都不一致。具体地说，根据两种说法，PFC的前部区域对实验条件表现出敏感性，而实验条件应该只选择性地与PFC的后部区域接触。因此，我们研究了第三个可能的解释(适应性语境维持假说)，该假说假设PFC的后部和前部区域都可靠地参与到需要积极维持语境信息的任务条件中，这些区域的活动的时间动态灵活地跟踪维持需求的持续时间。外侧PFC的活动模式与第三个假设是一致的：当必须以逐个试验的方式更新和维护上下文信息时，整个外侧PFC区域表现出短暂的激活，但当必须在一系列试验中保持上下文信息时，则表现出持续的激活。这些发现促使对当前关于外侧PFC的前后部组织的观点进行了重新的概念化，但也支持了其他关于外侧PFC在顺序工作记忆范式中的积极维持作用的发现。
The present experiment tested three hypotheses regarding the function and organization of lateral prefrontal cortex (PFC). The first account (the information cascade hypothesis) suggests that the anterior-posterior organization of lateral PFC is based on the timing with which cue stimuli reduce uncertainty in the action selection process. The second account (the levels-of-abstraction hypothesis) suggests that the anterior-posterior organization of lateral PFC is based on the degree of abstraction of the task goals. The current study began by investigating these two hypotheses, and identified several areas of lateral PFC that were predicted to be active by both the information cascade and levels-of-abstraction accounts. However, the pattern of activation across experimental conditions was inconsistent with both theoretical accounts. Specifically, an anterior area of mid-dorsolateral PFC exhibited sensitivity to experimental conditions that, according to both accounts, should have selectively engaged only posterior areas of PFC. We therefore investigated a third possible account (the adaptive context maintenance hypothesis) that postulates that both posterior and anterior regions of PFC are reliably engaged in task conditions requiring active maintenance of contextual information, with the temporal dynamics of activity in these regions flexibly tracking the duration of maintenance demands. Activity patterns in lateral PFC were consistent with this third hypothesis: regions across lateral PFC exhibited transient activation when contextual information had to be updated and maintained in a trial-by-trial manner, but sustained activation when contextual information had to be maintained over a series of trials. These findings prompt a reconceptualization of current views regarding the anterior-posterior organization of lateral PFC, but do support other findings regarding the active maintenance role of lateral PFC in sequential working memory paradigms.
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