1．意識障害の生理学—意識とは何か？ その障害をきたす疾患とメカニズム

What is “consciousness”?：The physiology of disorders of consciousness

まず医学でいうところの「意識」の定義について論じ，意識を担う解剖学的，生理学的な研究史を俯瞰し，上行性網様体賦活系（ARAS）を主体とした覚醒系の概念を解説する。そして，意識障害のメカニズムの概略に触れ，特に脳組織に直接の損傷はないものの意識障害を生じる疾患のいくつかについて，とりわけ動脈瘤性くも膜下出血と敗血症関連脳症については，両者ともに神経炎症が深くかかわっていることを解説する。

In this paper, the definition of “consciousness” in medicine is discussed. The history of anatomical and physiological research on consciousness is then reviewed, and the concept of the arousal system, mainly the ascending reticular activating system （ARAS） is discussed. The mechanisms of disorders of consciousness are outlined and then some of the diseases that can cause disorders of consciousness without direct damage to brain tissue are described. In particular, the aneurysmal subarachnoid hemorrhage and sepsis-related encephalopathy are discussed, both of which are strongly related to neuroinflammation.