Comparison of fMRI and iEEG metrics of hippocampal connectivity during memory encoding

项目总结 在情景记忆中理解人类神经生理学的两种最广泛使用的方法 编码是功能磁共振成像(FMRI)和颅内脑电(IEEG)。 然而，记忆过程中大脑活动的fMRI指标与 电生理活动尚不清楚，尤其是海马体及其相关结构。在……里面 在iEEG和fMRI的初步工作中，我们使用了几种方法来量化海马区的活动和 成功进行内存编码期间的连接性。在我们的第一个目标中，我们打算通过以下方式比较这些方法 立体脑电电极植入术后患者的术前功能磁共振 癫痫定位。这些参与者将在fMRI和iEEG期间执行相同的记忆任务 记录，我们假设记忆相关的海马区连接到脑区的调制 如后扣带回、角回、前额叶皮质和外侧颞叶皮质将高度 FMRI和iEEG之间的相关性。我们认为，海马区的连接调制将比 单个大脑区域内的活动。我们的第二个目标是使用皮质诱发电位图来开发 一张补充的海马体连接图，并将这些数据与功能连接进行比较 在内存编码期间。我们的研究结果将告诉我们一些基本的问题，即 记忆编码和检索，包括相位编码和同步通信的理论 在记忆过程中。我们的结果也将有助于改进记忆大小的预测模型 融合iEEG和fMRI信息的颞叶手术后的损失。

PROJECT SUMMARY Two of the most widely-used methods of understanding human neurophysiology during episodic memory encoding are functional magnetic resonance imaging (fMRI) and intracranial electroencephalography (iEEG). However, the relationship between fMRI metrics of brain activity during memory processes and electrophysiological activity is unclear, especially for the hippocampus and associated structures. In preliminary work with iEEG and fMRI, we have used several methods to quantify hippocampal activity and connectivity during successful memory encoding. In our first aim, we intend to compare these methods by performing pre-operative fMRI in patients who subsequently undergo stereo EEG electrode implantation for seizure localization. These participants will perform the same memory task during both fMRI and iEEG recording, and we hypothesize that memory-related modulation of hippocampal connectivity to brain areas such as the posterior cingulate, angular gyrus, pre-frontal cortex, and lateral temporal cortex will be highly correlated between fMRI and iEEG. We believe hippocampal connectivity modulation will be more similar than activity within single brain sites. Our second aim is to use cortico-cortical evoked potential mapping to develop a complementary connectivity map for the hippocampus and compare these data to functional connectivity during memory encoding. The results of our research will inform fundamental questions of the neural basis of memory encoding and retrieval, including theories of phase coding and communication through synchrony during memory processes. Our results will also help improve predictive models for the magnitude of memory loss after temporal lobe surgery by integrating iEEG and fMRI information.