Memory encoding and storage in cortical circuits: electrophysiological studies

新的记忆需要在大脑中形成新的记忆痕迹或“印记”。记忆痕迹被认为是由同时激活的神经元组成的网络，形成新网络的一个主要机制是通过神经元之间突触连接强度的长期增加(或减少)。我的研究旨在了解新的记忆痕迹是如何通过脑细胞之间突触连接强度的长期变化形成的。海马旁皮质和新皮质是大脑中对正常记忆形成至关重要的区域。在记忆编码过程中，海马区被认为结合了不同类型的感觉输入。然后，记忆被认为是通过与大脑的其他部分，包括新大脑皮层的连接来更持久地存储。为了更好地理解记忆形成的基本机制，我使用了各种电生理学和药理学技术来确定如何改变大鼠大脑的海马旁和新皮质区域的突触强度。有两条主要的研究路线。第一条线的研究旨在了解内嗅皮层(重要的海马旁区域)是如何处理和编码感觉输入的。实验研究了活动的时间模式如何增加或减少突触强度，以及内嗅觉皮质的活动如何受到副小结和鼻周围皮质的调节。这些实验很重要，因为它们可以表明在编码新记忆的过程中，神经回路是如何处理感觉信息的。第二条线的研究旨在了解记忆储存过程中大脑皮层发生的变化。实验将集中在识别受学习细胞模型影响的新皮质回路的元素，并表征皮质脑电节奏和神经元的形态变化，这些变化可能导致突触强度的长期变化。这一系列研究可能会帮助我们理解记忆是如何长时间储存在大脑皮层的。

A new memory requires the formation of a new memory trace, or "engram", in the brain. Memory traces are thought to consist of networks of simultaneously activated neurons, and a major mechanism through which new networks can be formed is through long-lasting increases (or decreases) in the strength of synaptic connections between neurons. My research is aimed at understanding how new memory traces are formed through long-lasting changes in the strength of synaptic connections between brain cells. The parahippocampal cortex and neocortex are regions of the brain that are crucial for normal memory formation. The parahippocampal area is thought to combine different types of sensory input during memory encoding. Memory is then thought to be stored more permanently through connections with other parts of the brain including the neocortex. To better understand the fundamental mechanisms that mediate memory formation, I use various electrophysiological and pharmacological techniques to determine how synaptic strengths can be altered in the parahippocampal and neocortical regions of the rat brain. There are two primary lines of research. The first line of research is aimed at understanding how the entorhinal cortex (an important parahippocampal area) processes and encodes sensory input. Experiments examine how temporal patterns of activity increase or decrease synaptic strength, and how activity in the entorhinal cortex can be modulated by the parasubiculum and perirhinal cortex. These experiments are important because they can indicate how sensory information is processed by neural circuits during the encoding of a new memory. The second line of research is aimed at understanding changes that occur in the neocortex during memory storage. Experiments will focus on identifying elements of the neocortical circuit that are affected by a cellular model of learning, and characterizing the cortical EEG rhythms and morphological changes in neurons that can lead to long-lasting changes in synaptic strength. This line of research may help us understand how memories can be stored in the neocortex for long periods of time.