Analysis of dynamic neuronal assemblies for memory processes of stimulus and temporal events

点击翻译按钮获取中文摘要

The present research investigated if the cell assembly, i.e., an ensemble population of neurons with flexible functional connections, is the basic neuronal code for information processes of memory in the brain. The main properties indicating the reality of cell-assembly coding are neurons overlapping among different assemblies and connection dynamics within and among the assemblies. The former can be detected as multiple functions of individual neurons in processing different kinds of information. Individual neurons appear to be involved in multiple information-processes. The latter can be detected as changes of functional synaptic connections in processing different kinds of information. Correlations of activity among some of the recorded neurons appear to change in multiple information-processes. The present experiments compared several different memory processes (tasks), including processings of stimulus and temporal events and searched for the two main properties. The first experim … More ent used rats as subjects and compared memory processes of stimulus (stimulus discrimination) and its presented duration (duration discrimination). Multineuronal activities from the hippocampal areas were recorded and analyzed when the rats were performing the both tasks. The second experiment used monkeys as subjects and compared short-term retention processes of memory for stimulus (delayed matching-to-sample of color) and its presented duration (delayed matching-to-sample of duration). Multineuronal activities from the prefrontal cortical areas were recorded and analyzed when the monkeys were performing the both tasks. By analyzing the individual neuronal activities and their activity correlations with each others, all theses experiments are demonstrating the two main properties of cell-assembly coding in processings of stimulus and temporal events. Also, the experiments are suggesting some different features of cell-assembly coding between the processings of stimulus and temporal events. Less