Neuronal connection changes related to auditory working and reference memory in the rat.

这项研究项目通过实验研究了与高级记忆的信息处理有关的小神经元回路、细胞组合中的连接变化。受试者为白化大鼠。需要记住的刺激有高音调和低音调。定义了一种在短时间内交替测试工作记忆和参考记忆的方法，在短时间内可以连续记录单元。在工作记忆和参考记忆任务中，仪器和刺激都是相同的。在这两个任务的执行过程中，从海马区或听觉区域同时记录了几个单位。频率直方图显示，单位在参考记忆任务和/或工作记忆任务中表现出与任务相关的活动。参考记忆任务比工作记忆任务有更多的任务相关单位。对每一对同时记录的单位进行互相关分析，以查看单位的突触连接图。到目前为止，分析表明，有几个单位改变了呈现音调和保持期之间的突触连接，或者改变了工作记忆和参考记忆任务之间的突触连接。兴奋性或抑制性输入比相互直接突触联系更常见。这些初步结果表明：1.一个神经元在不同的记忆过程中可能具有不同的功能。2.小神经元环路中的突触联系可以显示记忆任务中不同过程之间或不同记忆任务之间的动态变化。近期的研究方向如下：1.单个神经元功能之间的关系及其突触变化的可能性。2.突触变化的贡献变化。3.感觉区和海马区的差异。

This research project experimentally investigates connection changes in small neuronal circuits, cell assemblies, in relation to information processing of higher memory. The subjects were albino rats. The to-be-remembered stimuli were high and low tones. A method was defined to test working and reference memory alternatively in a short period in which units could be recorded continuously. The apparatus and stimuli were identical for both the working and reference memory tasks. Several units were recorded simultaneously from the hippocampal or auditory regions during the performance of both of the tasks. Frequency histograms revealed that units showed task-related activities in the reference memory task or working memory task or both of the tasks. The reference memory task had more task-related units than the working memory task had. Cross-correlation analysis was conducted for each pair of simultaneously recorded units to see synaptic connectivity diagrams of the units. To the present, the analysis has shown a few units which changed their synaptic connections between the tone-presented and the retention periods or between the working and reference memory tasks. There were more common excitatory or inhibitory inputs than mutual direct synaptic connections. These preliminary results indicate the followings : 1. A neuron could have different functions between the different memory processes. 2. Synaptic connections in a small neuronal circuit could show dynamic changes between the different processes in a memory task or between the different memory tasks. The followings should be investigated in the near future : 1. Relationship of functions of individual neurons and possibility of their synaptic changes. 2. Changes of contribution of synaptic changes. 3. Differences between the sensory and hippocampal regions.