Daselaar Sander M, Prince Steven E, Dennis Nancy A, Hayes Scott M, Kim Hongkeun, Cabeza Roberto
Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam Amsterdam, The Netherlands.
Front Hum Neurosci. 2009 Jul 20;3:13. doi: 10.3389/neuro.09.013.2009. eCollection 2009.
The ventral part of lateral posterior parietal cortex (VPC) and the posterior midline region (PMR), including the posterior cingulate cortex and precuneus, tend to show deactivation during demanding cognitive tasks, and have been associated with the default mode of the brain. Interestingly, PMR and VPC activity has been associated with successful episodic retrieval but also with unsuccessful episodic encoding. However, the differential contributions of PMR and VPC to retrieval vs. encoding has never been demonstrated within-subjects and within the same experiment. Here, we directly tested the prediction that PMR and VPC activity should be associated with retrieval success but with encoding failure. Consistent with this prediction, we found across five different fMRI experiments that, during retrieval, activity in these regions is greater for hits than misses, whereas during encoding, it is greater for subsequent misses than hits. We also found that these regions overlap with the ones that show deactivations during conscious rest. Our findings further aid in clarifying the role of the default mode regions in learning and memory.
外侧顶叶后皮质（VPC）的腹侧部分以及后中线区域（PMR），包括后扣带回皮质和楔前叶，在需要认知的任务中往往表现为失活，并且与大脑的默认模式有关。有趣的是，PMR和VPC的活动不仅与成功的情景记忆提取有关，还与不成功的情景记忆编码有关。然而，PMR和VPC对提取与编码的不同贡献从未在同一受试者内且在同一实验中得到证实。在这里，我们直接检验了以下预测：PMR和VPC的活动应与提取成功相关，但与编码失败相关。与这一预测一致，我们在五个不同的功能磁共振成像实验中发现，在提取过程中，这些区域的命中活动比未命中活动更强，而在编码过程中，后续未命中活动比命中活动更强。我们还发现，这些区域与在有意识休息期间表现出失活的区域重叠。我们的发现进一步有助于阐明默认模式区域在学习和记忆中的作用。
