Redefining the role of the default network in goal directed cognition

过去在我们的现在中回荡，塑造我们对未来的思考，指导当下的决策，并为未来制定预期。在解决问题、推理或计划等复杂的认知功能过程中获取过去的知识和经验，对于适应人类的功能是必不可少的。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，一组功能相连的大脑区域，即所谓的默认网络，参与了在认知意义上跨越时间和空间的自我投射。这些过程让我们超越眼前的环境，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起着重要作用。然而，许多研究表明，默认网络是任务负性的，在复杂的认知任务中受到抑制。这可能是实验室研究的产物，这些研究通常使用缺乏个人意义的刺激，因此无法参与默认的网络。我最近的研究在认知控制任务中利用对个人有意义的刺激，表明默认网络远不是任务消极的，而是一个连接记忆和认知控制的主动注意系统。*目前的提案将扩展这项工作，提供第一个关于认知控制中默认网络参与的系统调查。使用功能神经成像方法，初步研究将确定认知控制任务中默认网络活动的特定决定因素。第二系列研究将直接调查使用神经刺激方法扰乱默认网络活动如何影响认知控制性能。*定义默认网络在整合记忆和认知控制方面的作用，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，默认网络很容易在衰老和大脑疾病中受到干扰。虽然这里没有直接调查，但这项拟议的研究可能会提供关键的见解，将改变的默认网络功能与老年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找到新的途径。

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.