MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK.
Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK.
Cereb Cortex. 2020 Mar 14;30(3):1779-1796. doi: 10.1093/cercor/bhz202.
Complex cognition is dynamic, with each stage of a task requiring new cognitive processes appropriately linked to stimulus or other content. To investigate control over successive task stages, we recorded neural activity in lateral frontal and parietal cortex as monkeys carried out a complex object selection task, with each trial separated into phases of visual selection and learning from feedback. To study capacity limitation, complexity was manipulated by varying the number of object targets to be learned in each problem. Different task phases were associated with quasi-independent patterns of activity and information coding, with no suggestion of sustained activity linked to a current target. Object and location coding were largely parallel in frontal and inferior parietal cortex, though frontal cortex showed somewhat stronger object representation at feedback, and more sustained location coding at choice. At both feedback and choice, coding precision diminished as task complexity increased, matching a decline in performance. We suggest that, across successive task steps, there is radical but capacity-limited reorganization of frontoparietal activity, selecting different cognitive operations linked to their current targets.
复杂认知是动态的，任务的每个阶段都需要将新的认知过程适当地与刺激或其他内容联系起来。为了研究对连续任务阶段的控制，我们记录了猴子在执行一项复杂的物体选择任务时，外侧额顶叶皮层的神经活动，每次试验分为视觉选择和反馈学习两个阶段。为了研究容量限制，我们通过改变每个问题中要学习的物体目标数量来改变复杂性。不同的任务阶段与准独立的活动和信息编码模式相关，没有任何与当前目标相关的持续活动的迹象。物体和位置编码在额顶叶皮层的前部和下部大致平行，但在反馈时，额前皮质对物体的表示稍强，在选择时对位置的编码更为持续。在反馈和选择时，编码精度随着任务复杂性的增加而降低，与性能下降相匹配。我们认为，在连续的任务步骤中，额顶叶活动会发生根本性但容量有限的重新组织，选择与当前目标相关的不同认知操作。
