Sakurai Yoshio, Nakazono Tomoaki, Ishino Seiya, Terada Satoshi, Yamaguchi Kenji, Takahashi Susumu
Department of Psychology, Graduate School of Letters, Kyoto University, Kyoto 606-8501, Japan.
J Physiol Paris. 2013 Dec;107(6):459-70. doi: 10.1016/j.jphysparis.2013.05.004. Epub 2013 Jun 4.
In the present paper, we focus on the coding by cell assemblies in the prefrontal cortex (PFC) and discuss the diversity of the coding, which results in stable and dynamic representations and the processing of various information in that higher brain region. The key activity that reflects cell-assembly coding is the synchrony of the firing of multiple neurons when animals are performing cognitive and memory tasks. First, we introduce some studies that have shown task-related synchrony of neuronal firing in the monkey PFC. These studies have reported fixed and several types of dynamic synchronous firing during working memory, long-term visual memory, and goal selection. The results of these studies have indicated that cell assemblies in the PFC can contribute to both the stability and the dynamics of various types of information. Second, we refer to rat studies and introduce the findings of cellular interactions that contribute to synchrony in working memory, learning-induced changes in synchrony in spatial tasks, and interactions of the PFC and hippocampus in dynamic synchrony. These studies have proposed neuronal mechanisms of cell-assembly coding in the PFC and its critical role in the learning of task demands in problematic situations. Based on the monkey and rat studies, we conclude that cell-assembly coding in the PFC is diverse and has various facets, which allow multipotentiality in the higher brain region. Finally, we discuss the problem of the sizes of cell assembly, how diverse the sizes are in the PFC, and the technical problems in their investigation. We introduce a unique spike-sorting method that can detect small and local cell assemblies that consist of closely neighboring neurons. Then, we describe the findings of our study that showed that the monkey PFC has both small and large cell assemblies, which have different roles in information coding in the working brain.
在本论文中，我们聚焦于前额叶皮质（PFC）中细胞集群的编码，并讨论编码的多样性，这种多样性导致了该高级脑区中稳定和动态的表征以及各种信息的处理。反映细胞集群编码的关键活动是动物执行认知和记忆任务时多个神经元放电的同步性。首先，我们介绍一些已表明猴PFC中神经元放电与任务相关同步性的研究。这些研究报告了在工作记忆、长期视觉记忆和目标选择过程中固定的以及几种类型的动态同步放电。这些研究结果表明，PFC中的细胞集群有助于各种类型信息的稳定性和动态性。其次，我们提及大鼠研究，并介绍有助于工作记忆同步性的细胞间相互作用的研究结果、空间任务中学习诱导的同步性变化以及PFC与海马体在动态同步中的相互作用。这些研究提出了PFC中细胞集群编码的神经元机制及其在有问题情境中任务需求学习中的关键作用。基于猴和大鼠的研究，我们得出结论，PFC中的细胞集群编码是多样的且具有多个方面，这使得该高级脑区具有多潜能性。最后，我们讨论细胞集群大小的问题、PFC中大小的多样性以及研究它们时的技术问题。我们介绍一种独特的尖峰分类方法，该方法可以检测由紧密相邻神经元组成的小的和局部的细胞集群。然后，我们描述我们的研究结果，该结果表明猴PFC既有小的细胞集群也有大的细胞集群，它们在工作大脑的信息编码中具有不同作用。
