Department of Cognitive Neuroscience, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Cereb Cortex. 2010 Nov;20(11):2675-83. doi: 10.1093/cercor/bhq013. Epub 2010 Feb 12.
The prefrontal cortex (PFC) is thought to modulate the neural network state in favor of the processing of task-relevant sensory information prior to the presentation of sensory stimuli. However, this proactive control mechanism cannot always optimize the network state because of intrinsic fluctuation of neural activity upon arrival of sensory information. In the present study, we have investigated an additional control mechanism, in which the control process to regulate the behavior is adjusted to the trial-by-trial fluctuation in neural representations of sensory information. We asked normal human subjects to perform a variant of the Stroop task. Using functional magnetic resonance imaging, we isolated cognitive conflict at a sensory processing stage on a single-trial basis by calculating the difference in activation between task-relevant and task-irrelevant sensory areas. Activation in the dorsolateral PFC (DLPFC) covaried with the neural estimate of sensory conflict only on incongruent trials. Also, the coupling between the DLPFC and anterior cingulate cortex (ACC) was tighter on high-sensory conflict trials with fast response. The results suggest that although detection of sensory conflict is achieved by the DLPFC, online behavioral adjustment is achieved by interactive mechanisms between the DLPFC and ACC.
前额皮质（prefrontal cortex，PFC）被认为可以调节神经网络状态，使其有利于在感觉刺激呈现之前处理与任务相关的感觉信息。然而，由于感觉信息到达时神经活动的固有波动，这种主动控制机制并不总是能够优化网络状态。在本研究中，我们研究了另一种控制机制，其中调节行为的控制过程会根据感觉信息的神经表示的逐次波动进行调整。我们要求正常人类受试者执行一种 Stroop 任务的变体。使用功能磁共振成像，我们通过计算任务相关和任务无关感觉区域之间的激活差异，在单次试验的基础上分离出感觉处理阶段的认知冲突。背外侧前额皮质（dorsolateral prefrontal cortex，DLPFC）的激活仅在不一致的试验中与感觉冲突的神经估计值相关。此外，DLPFC 和前扣带皮层（anterior cingulate cortex，ACC）之间的耦合在反应较快的高感觉冲突试验中更紧密。结果表明，虽然感觉冲突的检测是由 DLPFC 完成的，但在线行为调整是由 DLPFC 和 ACC 之间的交互机制完成的。
