2010 年 50 巻 2 号 p. 084-087
We introduce the original and present concepts of cell assembly in the working brain and discuss the problem of dynamic size of it. A local cell assembly consisting of closely neighboring neurons was especially difficult to be detected because of spike overlapping of neighboring neurons. We developed a unique technique of spike-sorting that employed independent component analysis and showed that most of closely neighboring neurons in the monkey prefrontal cortex had dynamic and sharp synchrony of firing reflecting local cell assemblies. We propose that real features of cell assemblies could contribute to development of brain-machine interfaces and neuro-rehabilitation.