Kragel James E, Ezzyat Youssef, Sperling Michael R, Gorniak Richard, Worrell Gregory A, Berry Brent M, Inman Cory, Lin Jui-Jui, Davis Kathryn A, Das Sandhitsu R, Stein Joel M, Jobst Barbara C, Zaghloul Kareem A, Sheth Sameer A, Rizzuto Daniel S, Kahana Michael J
Department of Psychology, University of Pennsylvania, Philadelphia PA 19104, USA.
Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
Neuroimage. 2017 Jul 15;155:60-71. doi: 10.1016/j.neuroimage.2017.03.042. Epub 2017 Apr 2.
Neural networks that span the medial temporal lobe (MTL), prefrontal cortex, and posterior cortical regions are essential to episodic memory function in humans. Encoding and retrieval are supported by the engagement of both distinct neural pathways across the cortex and common structures within the medial temporal lobes. However, the degree to which memory performance can be determined by neural processing that is common to encoding and retrieval remains to be determined. To identify neural signatures of successful memory function, we administered a delayed free-recall task to 187 neurosurgical patients implanted with subdural or intraparenchymal depth electrodes. We developed multivariate classifiers to identify patterns of spectral power across the brain that independently predicted successful episodic encoding and retrieval. During encoding and retrieval, patterns of increased high frequency activity in prefrontal, MTL, and inferior parietal cortices, accompanied by widespread decreases in low frequency power across the brain predicted successful memory function. Using a cross-decoding approach, we demonstrate the ability to predict memory function across distinct phases of the free-recall task. Furthermore, we demonstrate that classifiers that combine information from both encoding and retrieval states can outperform task-independent models. These findings suggest that the engagement of a core memory network during either encoding or retrieval shapes the ability to remember the past, despite distinct neural interactions that facilitate encoding and retrieval.
横跨内侧颞叶（MTL）、前额叶皮质和后皮质区域的神经网络对人类的情景记忆功能至关重要。皮质中不同的神经通路以及内侧颞叶内的共同结构共同支持编码和检索过程。然而，记忆表现可由编码和检索共有的神经处理过程决定的程度仍有待确定。为了识别成功记忆功能的神经特征，我们对187名植入硬膜下或脑实质内深度电极的神经外科患者进行了延迟自由回忆任务。我们开发了多变量分类器，以识别大脑中频谱功率的模式，这些模式可独立预测情景编码和检索的成功。在编码和检索过程中，前额叶、MTL和顶下皮质高频活动增加的模式，伴随着全脑低频功率的普遍降低，预示着记忆功能成功。使用交叉解码方法，我们展示了预测自由回忆任务不同阶段记忆功能的能力。此外，我们证明，结合编码和检索状态信息的分类器比与任务无关的模型表现更好。这些发现表明，尽管存在促进编码和检索的不同神经相互作用，但在编码或检索过程中核心记忆网络的参与塑造了记住过去的能力。
