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

项目摘要 了解人类在情景记忆中的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）和颅内脑电图（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，特别是海马和相关结构。在 在iEEG和fMRI的初步工作中，我们使用了几种方法来量化海马活动， 在成功的内存编码过程中连接。在我们的第一个目标，我们打算比较这些方法， 在随后接受立体EEG电极植入的患者中进行术前fMRI， 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调制海马连接到大脑区域， 例如后扣带回、角回、前额叶皮层和外侧颞叶皮层， fMRI和iEEG之间的相关性我们相信海马体的连接调节将比 在单个大脑部位的活动。我们的第二个目标是使用皮质-皮质诱发电位映射来开发 海马体的互补连接图，并将这些数据与功能连接进行比较 在记忆编码过程中。我们的研究结果将告知神经基础的基本问题， 记忆编码和检索，包括相位编码和同步通信理论 在记忆过程中。我们的研究结果还将有助于改善记忆大小的预测模型 整合iEEG和fMRI信息的颞叶手术后丢失。

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.