Department of Psychology, University of York, England, UK.
Department of Psychology, University of York, England, UK.
Neuroimage. 2019 Nov 15;202:116045. doi: 10.1016/j.neuroimage.2019.116045. Epub 2019 Jul 23.
Understanding the neural processes that support different patterns of ongoing thought is an important goal of contemporary cognitive neuroscience. Early accounts assumed the default mode network (DMN) was especially important for conscious attention to task-irrelevant/personally relevant materials. However, simple task-negative accounts of the DMN are incompatible with more recent evidence that neural patterns within the system can be related to ongoing processing during active task states. To better characterise the contribution of the DMN to ongoing thought, we conducted a cross-sectional analysis of the relationship between the structural organisation of the brain, as indexed by cortical thickness, and patterns of experience, identified using experience sampling in the cognitive laboratory. In a sample of 181 healthy individuals (mean age 20 years, 117 females) we identified an association between cortical thickness in the anterior parahippocampus and patterns of task focused thought, as well as an adjacent posterior region in which cortical thickness was associated with experiences with higher levels of subjective detail. Both regions fell within regions of medial temporal lobe associated with the DMN, yet varied in their functional connectivity: the time series of signals in the 'on-task' region were more correlated with systems important for external task-relevant processing (as determined by meta-analysis) including the dorsal and ventral attention, and fronto-parietal networks. In contrast, connectivity within the region linked to subjective 'detail' was more correlated with the medial core of the DMN (posterior cingulate and the medial pre-frontal cortex) and regions of primary visual cortex. These results provide cross-sectional evidence that confirms a role of the DMN in how detailed experiences are and so provide further evidence that the role of this system in experience is not simply task-irrelevant. Our results also highlight processes within the medial temporal lobe, and their interactions with other regions of cortex, as important in determining multiple aspects of how human cognition unfolds.
理解支持不同持续思维模式的神经过程是当代认知神经科学的一个重要目标。早期的解释假设默认模式网络（DMN）对于有意识地注意任务无关/个人相关的材料特别重要。然而，DMN 的简单任务负解释与最近的证据不一致，即系统内的神经模式可以与主动任务状态下的持续处理有关。为了更好地描述 DMN 对持续思维的贡献，我们对大脑结构组织（以皮质厚度为指标）与认知实验室经验采样中确定的经验模式之间的关系进行了横断面分析。在 181 名健康个体的样本中（平均年龄 20 岁，117 名女性），我们发现了前旁海马皮质厚度与任务聚焦思维模式之间的关联，以及相邻的后区域，其中皮质厚度与具有更高主观细节水平的经验相关。这两个区域都位于与 DMN 相关的内侧颞叶区域内，但在其功能连接上有所不同：“任务中”区域的时间序列信号与外部任务相关处理（通过元分析确定）重要的系统更为相关，包括背侧和腹侧注意力以及额顶叶网络。相比之下，与主观“细节”相关的区域内的连接与 DMN 的内侧核心（后扣带回和内侧前额叶皮层）以及初级视觉皮层更为相关。这些结果提供了横断面证据，证实了 DMN 在详细体验方面的作用，因此提供了进一步的证据，表明该系统在体验中的作用不仅仅是任务无关的。我们的结果还突出了内侧颞叶内的过程及其与皮质其他区域的相互作用，这些过程对于确定人类认知展开的多个方面都很重要。
