Department of Psychiatry, University of Ulm, Leimgrubenweg 12, 89075 Ulm, Germany.
Brain Res. 2011 Nov 3;1421:52-65. doi: 10.1016/j.brainres.2011.09.022. Epub 2011 Sep 17.
Cognitive control can be adapted flexibly according to the conflict level in a given situation. In the Eriksen flanker task, interference evoked by flankers is larger in conditions with a higher, rather than a lower proportion of compatible trials. Such compatibility ratio effects also occur for stimuli presented at two spatial locations suggesting that different cognitive control settings can be simultaneously maintained. However, the conditions and the neural correlates of this flexible adaptation of cognitive control are only poorly understood. In the present study, we further elucidated the mechanisms underlying the simultaneous maintenance of two cognitive control settings. In behavioral experiments, stimuli were presented centrally above and below fixation and hence processed by both hemispheres or lateralized to stimulate hemispheres differentially. The different compatibility ratio at two stimulus locations had a differential influence on the flanker effect in both experiments. In an fMRI experiment, blocks with an identical compatibility ratio at two central spatial locations elicited stronger activity in a network of prefrontal and parietal brain areas, which are known to be involved in conflict resolution and cognitive control, as compared with blocks with a different compatibility ratio at the same spatial locations. This demonstrates that the simultaneous maintenance of two conflicting control settings vs. one single setting does not recruit additional neural circuits suggesting the involvement of one single cognitive control system. Instead a crosstalk between multiple control settings renders adaptation of cognitive control more efficient when only one uniform rather than two different control settings has to be simultaneously maintained.
认知控制可以根据给定情境中的冲突水平灵活地进行调整。在 Eriksen 侧翼任务中，当相容试次的比例较高而非较低时，侧翼引起的干扰更大。这种相容性比例效应也出现在呈现于两个空间位置的刺激上，这表明可以同时维持不同的认知控制设置。然而，这种认知控制的灵活适应性的条件和神经相关物还知之甚少。在本研究中，我们进一步阐明了同时维持两种认知控制设置的机制。在行为实验中，刺激呈现在注视点上方和下方的中央位置，因此被两个半球处理，或者偏向于刺激不同的半球。在两个实验中，两个刺激位置的不同相容性比例对侧翼效应有不同的影响。在 fMRI 实验中，与在相同空间位置具有不同相容性比例的块相比，在两个中央空间位置具有相同相容性比例的块在涉及冲突解决和认知控制的前额叶和顶叶脑区网络中引起了更强的活动。这表明，与同时维持一个单一的控制设置相比，同时维持两个冲突的控制设置不会招募额外的神经回路，这表明涉及一个单一的认知控制系统。相反，多个控制设置之间的串扰使得认知控制的适应更加高效，因为只需要同时维持一个统一的控制设置而不是两个不同的控制设置。
