NEURONAL SYNCHRONIZATION IN THE MEDIAL TEMPORAL LOBE AND MEMORY FORMATION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 猴子内侧颞叶结构的损伤会损害视觉识别记忆任务--视觉优先看任务(VPLT)的表现。该项目试图确定支持清醒、行为正常的猴子VPLT记忆表现的神经机制。在过去的一年里，我们完成了数据收集和分析，证明海马神经元之间伽马频率(40-100赫兹)同步增加与增强识别记忆有关。我们在逐一试验的基础上表明，编码过程中增加的同步性预示着成功的后续识别记忆性能。 我们还完成了一些分析，证明单个海马神经元根据刺激的新颖性来调节它们的放电率。此外，这种调制的大小与识别记忆性能相关。总而言之，这些研究表明，海马体机制，无论是在单个神经元和网络水平上，都是成功识别记忆的基础。 最后，我们最近收集的数据表明，在灵长类动物的海马体中存在theta带振荡，并且这些振荡的相位在视觉探索过程中被眼球运动重置。此外，我们最近的数据显示，theta带相位调制了伽马带活动的能量。综上所述，这些数据表明，在注视开始时，将theta频段振荡的相位重置到理想状态，可能会使海马区的活动与伽马频段同步和记忆形成的最佳状态保持一致。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Damage to medial temporal lobe structures in monkeys impairs performance on a task of visual recognition memory, the Visual Preferential Looking Task (VPLT). This project seeks to identify the neuronal mechanisms that support memory performance on the VPLT in awake, behaving monkeys. In the past year, we finished data collection and analyses which demonstrated that increased gamma-frequency (40-100 Hz) synchronization among hippocampal neurons is associated with enhanced recognition memory. We showed, on a trial-by-trial basis, that Increased synchrony during encoding predicts successful subsequent recognition memory performance. We have also completed analyses that demonstrate that individual hippocampal neurons modulate their firing rates based on stimulus novelty. Furthermore, the magnitude of this modulation is correlated with recognition memory performance. Together, these studies suggest that hippocampal mechanisms, both at the single neuron and network level, underlie successful recognition memory. Finally, we have recently collected data that demonstrate the existence of theta-band oscillations in the primate hippocampus, and that the phase of these oscillations is reset by eye-movements during visual exploration. In addition, our recent data showed that theta-band phase modulates the power of gamma-band activity. Together, these data suggest that phase resetting of the theta-band oscillation to an 'ideal phase' upon fixation onset may align hippocampal activity to an optimal state with respect to gamma-band synchronization and memory formation.