大脳皮質の神経細胞配置と統合失調症

Neuronal Distribution in the Cerebral Cortex and Its Significance in Schizophrenia

はじめに

　統合失調症の脳病理所見として，大脳皮質の微細な組織構築の異常が指摘されている。中でも，神経細胞配置の異常は，脳の発達段階において生じると考えられ，統合失調症の神経発達障害仮説に合致する所見と捉えられる。しかしその一方で，神経細胞配置の異常と統合失調症の発症の関連は明らかではない。本稿では，統合失調症の神経発達障害仮説と，正常の大脳皮質の組織構造およびその形成過程を説明したのち，統合失調症で報告された大脳皮質の微細組織構築の変化について概説する。また，それらの微細組織構築の異常がどのように生じるのか，そして統合失調症の症状にどのように結びつくのかについて考察する。

Abstract

　Abnormal cortical architectures have been identified as one of the microscopic neuropathological findings of schizophrenia. Among such findings, the altered distribution of neurons is suggestive of deficits during brain development and is consistent with the neurodevelopmental hypothesis of schizophrenia. However, the relationship between altered neuronal distribution and emergence of psychosis is unclear. In this review, we discuss the neurodevelopmental hypothesis of schizophrenia and describe the normal architecture of the neocortex and the recent findings regarding neocortical development. Thereafter, we summarize the abnormal cortical architectures reported for the brains of patients with schizophrenia. Furthermore, on the basis of the recent findings regarding cortical development, we suggest a mechanism for the formation of abnormal cortical architectures in schizophrenia and speculate how it could relate to some of the symptoms of schizophrenia.