Department of Psychology, University of York, UK.
Department of Psychology, University of York, UK.
Neuroimage. 2019 Jan 15;185:286-299. doi: 10.1016/j.neuroimage.2018.09.069. Epub 2018 Sep 25.
Cognition is dynamic, allowing us the flexibility to shift focus from different aspects of the environment, or between internally- and externally-oriented trains of thought. Although we understand how individuals switch attention across different tasks, the neurocognitive processes that underpin the dynamics of less constrained elements of cognition are less well understood. To explore this issue, we developed a paradigm in which participants intermittently responded to external events across two conditions that systematically vary in their need for updating working memory based on information in the external environment. This paradigm distinguishes the influences on cognition that emerge because of demands placed by the task (sustained) from changes that result from the time elapsed since the last task response (transient). We used experience sampling to identify dynamic changes in ongoing cognition in this paradigm, and related between subject variation in these measures to variations in the intrinsic organisation of large-scale brain networks. We found systems important for attention were involved in the regulation of off-task thought. Coupling between the ventral attention network and regions of primary motor cortex was stronger for individuals who were able to regulate off-task thought in line with the demands of the task. This pattern of coupling was linked to greater task-related thought when environmental demands were high and elevated off-task thought when demands were low. In contrast, the coupling of the dorsal attention network with a region of lateral visual cortex was stronger for individuals for whom off-task thoughts transiently increased with the time since responding to the external world . This pattern is consistent with a role for this system in the time-limited top-down biasing of visual processing to increase behavioural efficiency. Unlike the attention networks, coupling between regions of the default mode network and dorsal occipital cortex was weaker for individuals for whom the level of detail decreased with the passage of time when the external task did not require continuous monitoring of external information. These data provide novel evidence for how neural systems vary across subjects and may underpin individual variation in the dynamics of thought, linking attention systems to the maintenance of task-relevant information, and the default mode network to supporting experiences with vivid detail.
认知是动态的，使我们能够灵活地将注意力从环境的不同方面转移，或者在内部和外部思维之间转移。虽然我们了解个体如何在不同任务之间切换注意力，但支持认知较少受限制元素动态的神经认知过程理解得还不够。为了探索这个问题，我们开发了一种范式，参与者在两种条件下间歇性地对外界事件做出反应，这两种条件在根据外部环境信息更新工作记忆方面的需求上系统地有所不同。这种范式区分了由于任务要求（持续）而对认知产生影响的因素，以及由于上一次任务反应以来时间的流逝而导致的变化（瞬态）。我们使用经验抽样来识别该范式中持续进行的认知的动态变化，并将这些测量值在个体之间的变化与大脑大规模网络的内在组织的变化联系起来。我们发现，注意力系统在调节与任务无关的思维方面发挥了重要作用。腹侧注意网络与初级运动皮层区域之间的耦合对于能够根据任务要求调节与任务无关的思维的个体更强。当环境需求高时，这种耦合模式与更高的与任务相关的思维相关，而当需求低时，与更高的与任务无关的思维相关。相比之下，对于那些与任务无关的思维随着对外界世界反应的时间而短暂增加的个体，背侧注意网络与外侧视觉皮层区域之间的耦合更强。这种模式与该系统在有限时间内对视觉处理进行自上而下偏向以提高行为效率的作用一致。与注意力网络不同，当外部任务不需要连续监控外部信息时，默认模式网络与背外侧枕叶区域之间的耦合对于那些随着时间的推移详细程度降低的个体较弱。这些数据为神经系统如何在个体之间变化提供了新的证据，并可能为思维动态的个体差异提供了依据，将注意力系统与维持与任务相关的信息联系起来，将默认模式网络与支持具有生动细节的经验联系起来。
