Parietal Representations of Stimulus Features Are Amplified during Memory Retrieval and Flexibly Aligned with Top-Down Goals
Parietal Representations of Stimulus Features Are Amplified during Memory Retrieval and Flexibly Aligned with Top-Down Goals
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DOI：
10.1523/jneurosci.0564-18.2018
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发表时间：
2018-09-05
影响因子：
5.3
通讯作者：
Kuhl, Brice A.
中科院分区：
文献类型：
--
作者：
Favila, Serra E.;Samide, Rosalie;Kuhl, Brice A.
在人类情景记忆的研究中，传统上在涉及视觉感知的枕颞叶皮层（OTC）区域观察到再激活现象。然而，再激活也发生在侧顶叶皮层（LPC），最近的证据表明，刺激特异性再激活可能是更强的LPC比OTC。这些意见提出了重要的问题，在LPC的记忆表示的性质和它们之间的关系，在OTC表示。在这里，我们报告两个fMRI实验，量化LPC和OTC内的刺激特征信息（颜色和对象类别），分别在感知和记忆检索，在男性和女性人类受试者。在这两个实验中，我们观察到OTC和LPC之间存在明显的分离：虽然OTC中的特征信息在感知期间比记忆期间相对更强，但LPC中的特征信息在记忆期间比感知期间相对更强。因此，虽然OTC和LPC在我们的实验中代表了共同的刺激特征，但它们在不同的阶段优先代表了这些信息。在LPC中，这种偏向于记忆信息的现象与记忆提取过程中刺激水平的恢复同时发生。在实验2中，我们考虑了LPC中的助记特征信息是否被自上而下的检索目标灵活地动态地塑造。事实上，我们发现背侧LPC优先代表检索到的满足当前目标的特征信息。相反，腹侧LPC代表检索功能独立于当前目标。总的来说，这些研究结果提供了深入了解LPC的记忆表征的性质和意义，并构成了一个重要的桥梁之间假定的记忆和顶叶皮层的控制功能。
In studies of human episodic memory, the phenomenon of reactivation has traditionally been observed in regions of occipitotemporal cortex (OTC) involved in visual perception. However, reactivation also occurs in lateral parietal cortex (LPC), and recent evidence suggests that stimulus-specific reactivation may be stronger in LPC than in OTC. These observations raise important questions about the nature of memory representations in LPC and their relationship to representations in OTC. Here, we report two fMRI experiments that quantified stimulus feature information (color and object category) within LPC and OTC, separately during perception and memory retrieval, in male and female human subjects. Across both experiments, we observed a clear dissociation between OTC and LPC: while feature information in OTC was relatively stronger during perception than memory, feature information in LPC was relatively stronger during memory than perception. Thus, while OTC and LPC represented common stimulus features in our experiments, they preferentially represented this information during different stages. In LPC, this bias toward mnemonic information co-occurred with stimuluslevel reinstatement during memory retrieval. In Experiment 2, we considered whether mnemonic feature information in LPC was flexibly and dynamically shaped by top-down retrieval goals. Indeed, we found that dorsal LPC preferentially represented retrieved feature information that addressed the current goal. In contrast, ventral LPC represented retrieved features independent of the current goal. Collectively, these findings provide insight into the nature and significance of mnemonic representations in LPC and constitute an important bridge between putative mnemonic and control functions of parietal cortex.