知觉训练诱导的听觉皮层和海马可塑性及其机制研究

Perceptual training induced-plasticity in the mature brain has been reported in many previous studies. In the auditory system, it has been shown that auditory training significantly modifies temporal and spectral processing selectivity, response strengths, and representational topographies in the adult auditory cortex. Neural basis underlying these training-induced plastic changes, however, remain largely unknown. By using modified go/no-go behavioral tasks, the aim of the proposal is to investigate cortical changes induced by auditory perceptual training and diffusion effects of training from the auditory to the learning and memory systems. Specifically, we will study training-induced changes in the auditory cortex of adult rats at different levels (i.e., pathway, network, and synapse). As behavioral tasks applied here in this proposal have significant learning and memory components (i.e., they require animals to identify a remembered target stimulus from a set of distracter stimuli), we will also examine the possible consequences of training on efficiency of synaptic transfer and expressions of certain molecules in the hippocampus, a brain structure believed to contribute to learning and memory function. Results of these proposed studies shall help to understand neural mechanisms underlying training-based plasticity in both sensory and learning and memory systems in the mature brain.

知觉训练诱导成年脑可塑性已有诸多报道，但相关的神经机制尚待深入研究。本项目拟以成年大鼠为实验动物，采用自行设计的go/no-go听知觉训练范式，在通路、神经网络及突触分子等不同水平和层次探讨知觉训练诱导听觉皮层可塑性的神经机制。鉴于该听知觉训练范式包含明显的学习记忆成分，本项目还将进一步研究知觉训练诱导海马可塑性的个体行为表征及其突触传递效能和相关分子表达变化。从听觉和相关的学习记忆系统（即听皮层和海马）探讨听知觉训练诱导的可塑性及其扩散效应是本项目的主要特色。研究结果有助深入了解知觉训练诱导成年感觉及学习记忆功能可塑性的中枢机制，对阐明成年脑可塑性机理也具普适意义。

个体对感觉信息的加工因训练而得到改变并最终影响感知的范式即为知觉训练（Perceptual training），该范式被广泛应用于研究成年脑的可塑性。目前为止，知觉训练诱导成年脑可塑性的神经机制尚待深入研究。本项目以成年大鼠为实验动物，采用自行设计的go/no-go听知觉训练范式，通过多种实验技术考察知觉训练诱导听觉皮层可塑性的神经机制。鉴于该听知觉训练范式包含明显的学习记忆成分，本项目还进一步探讨了知觉训练诱导海马可塑性的个体行为表征及其突触传递效能和相关分子表达的变化。我们的研究表明：1）知觉训练能提高个体听觉重复率分辨能力以及海马相关的学习记忆能力；2）听皮层神经元的声时相信息处理能力随训练提高，这和突触后兴奋/抑制整合改变有关；3）训练改变海马长时程增强（Long-term potentiation, LTP）效应以及相关调控分子表达。我们推测知觉训练诱导的听皮层及海马可塑性变化可能是听觉及学习记忆相关行为改变的神经机制之一。这些研究结果有助深入了解知觉训练诱导成年感觉及学习记忆功能可塑性的中枢机制，对阐明成年脑可塑性机理也具普适意义。