From single units to local field potentials: Study of the timing of medial temporal lobe responses in humans

研究表明，人类“海马体”（位于处理感觉信息通路末端的区域）中的神经元的反应明显晚于猴子。一种可能的解释是，这是由于人类进一步处理感官刺激以产生抽象概念和联想的事实。但是大脑是如何保持这些反应的时间的呢？这些神经元是如何知道何时放电的呢？为了解决这个问题，我将使用由于临床原因放置在癫痫患者大脑中的颅内电极记录。我将从单个神经元的放电和大量神经元的平均活动两方面深入研究神经反应的时间动态，从而得出所谓的局部场电位（LFPs）。特别是，我将探讨lfp是否在研究范围内提供时间信息。使用不同的实验操作，我将探索识别时间变化对神经反应的影响，并且考虑到这些区域对记忆存储至关重要，这些发现可能对提高我们对记忆形成和记忆障碍（如阿尔茨海默病）的理解具有长期相关性。

It has been shown that neurons in the human ‘hippocampus‘, an area at the end of the pathway for processing sensory information, respond significantly later than in monkeys. A possible explanation is that this is due to the fact that humans process sensory stimuli much further to create abstract concepts and associations. But how does the brain keep the timing of these responses? How do these neurons know when to fire?To address this question, I will use recordings with intracranial electrodes placed in the brain of epileptic patients for clinical reasons. I will thoroughly study the temporal dynamics of the neural responses both in terms of the firing of individual neurons and the average activity of a large number of neurons, leading to the so called Local Field Potentials (LFPs). Particularly, I will explore whether the LFPs provide the timing information in the areas under study. Using different experimental manipulations, I will explore the consequences in the neural responses of variations of the timing for recognition and given that these areas are critical for memory storage, these finding may have long term relevance for improving our understanding on memory formation and memory disorders, such as Alzheimer‘s disease.