观察空间工作记忆过程中海马CA1区神经元群的放电特征。应用多通道神经元集群放电记录技术,同步观察和记录清醒大鼠在执行延迟选择任务时的行为轨迹以及海马CA1区神经元的放电活动。发现:海马CA1区位置细胞的位置野是在学习过程中逐渐形成并可消退;部分位置细胞的放电对未来目标定向性行为具有预测作用;在空间工作记忆过程中,神经元放电之间的相关性加强,神经元之间以及神经元与局部场电位之间存在相位编码方式。结果提示海马CA1区神经元参与对空间信息的初级编码和加工,并为未来行为决策提供有效信息,而且海马对信息的加工是通过局部神经网络进行,时间编码可能是海马信息加工的重要方式之一。
Hippocampus plays a vital role in the formation of spatial working memory. The brain encodes spatial information by generating spatial cognitive map in hippocampus. The mechanism with which hippocampus encodes, integrates, and extracts information remains unclear. According to Hebb's cell assembly hypothesis, spatial information is distributed in neural network. In this study, the dynamic processing of neuronal information in hippocampus CA1 neurons was observed in behaving adult rats and the neuronal mechanisms of spatial working memory were analyzed. A 16-channel (2x8) multi-electrode array was surgically imbedded into hippocampus CA1 area under general anesthetization. After the animals recovered from the surgery, they were trained in T-maze for delay-alternation task. 13 training trials (inter-trials interval 20 sec) were performed each day for about 7-14days. The multi-electrode array was cable-connected to a multi-channel acquisition system for simultaneous recording and displaying of neuronal units discharges and local field potentials. While the neuronal signals and animal spatial positions were recorded, the event marker was inputted in synchrony. Relationships between the events and neuronal unit discharges or local field potentials were analyzed during spatial memory formation. It was found that hippocampus CA1 neurons exhibited discharges correlating to door-opening and turning. Based on the correlating events, CA1 neurons can be classified into door-opening neurons, turning neurons, and double-place field neurons. When the animals were in the stem of the T-maze, hippocampus neurons showed context-dependent differential discharging. Some neurons showed discharges that predicted goal-directed behavior. The place fields of place neurons were gradually formed during learning and memory, but they were not stable until the formation of memory. The correlations between neurons also became stronger during memory formation. The same or different theta oscillation (4-12Hz) was observed between