Redefining the role of the default network in goal directed cognition

过去与我们的现在相呼应，塑造我们对未来的思考，指导当下的决定，并构建对未来的期望。在解决问题、推理或规划等复杂的认知功能中，获取过去的知识和经验对人类的适应性功能至关重要。然而，支持记忆和认知控制功能相互作用的神经机制仍然知之甚少。******我的工作表明，在认知意义上，大脑中有一组功能相连的区域，被称为默认网络，参与了自我在时间和空间上的投射。这些过程使我们能够超越眼前的环境，追忆过去，规划未来。这表明默认网络可能在整合记忆和认知控制过程中发挥重要作用。然而，许多研究表明恰恰相反——默认网络是“任务负性的”，在复杂的认知任务中被抑制。这可能是实验室研究的产物，通常使用缺乏个人意义的刺激，因此无法参与默认网络。我最近的研究，在认知控制任务中利用个人有意义的刺激，表明默认网络，远不是“任务负性”，是一个连接记忆和认知控制的活跃注意力系统。******目前的建议将扩展这项工作，提供默认网络参与认知控制的第一个系统调查。使用功能性神经成像方法，初步研究将确定认知控制任务中默认网络活动的具体决定因素。第二个系列的研究将直接调查如何破坏默认网络活动，使用神经刺激方法，影响认知控制性能。******定义默认网络在整合记忆和认知控制中的作用，将有助于我们理解复杂的人类行为是如何在大脑中实现的。此外，默认网络在衰老和脑部疾病中容易受到破坏。虽然这里没有直接调查，但拟议的研究可能提供关键的见解，将默认网络功能的改变与老年人认知控制的变化联系起来。这将为研究与年龄相关的认知衰退相关的神经机制确定新的途径。

The past echoes through our present and shapes our thinking about the future, guiding decisions in the moment, and framing expectations for the time ahead. Accessing past knowledge and experience during complex cognitive functions such as problem-solving, reasoning or planning is essential for adaptive human functioning. Yet the neural mechanisms that support this interaction of memory and cognitive control functions remain poorly understood. ******My work has shown that an assembly of functionally-connected brain regions, known as the default network, is involved in projecting oneself, in a cognitive sense, across time and space. These processes allow us to transcend our immediate environment, to reminisce about the past, and plan for the future. This suggests that the default network may play an important role in integrating memory and cognitive control processes. Yet many studies suggest just the opposite – that the default network is ‘task-negative', and suppressed during complex cognitive tasks. This may be an artifact of laboratory studies which typically use stimuli devoid of personal meaning, and thus fail to engage the default network. My recent research, utilizing personally-meaningful stimuli during a cognitive control task, suggests that the default network, far from being ‘task-negative', is an active attentional system linking memory and cognitive control. ******The current proposal will extend this work, providing the first systematic investigation of default network involvement in cognitive control. Using functional neuroimaging methods, initial studies will identify the specific determinants of default network activity during cognitive control tasks. A second series of studies will directly investigate how disrupting default network activity, using neurostimulation methods, impacts cognitive control performance. ******Defining the role of the default network in integrating memory and cognitive control will advance our understanding of how complex human behaviors are implemented in the brain. Further, the default network is susceptible to disruption in aging and brain disease. While not directly investigated here, the proposed research may provide critical insights linking altered default network functioning to changes in cognitive control in older adulthood. This would identify novel avenues for investigating neural mechanisms associated with age related cognitive decline.