This article explores the conceptualization of brain diseases or illnesses connected to the brain that can be found in medial books that circulated in Chile during the 18th century. It studies notions about brain diseases listed in books of surgery and general medicine, focusing particular on popularizing medical books aimed at a lay public.The article examines where brain diseases appear and how they are characterized, showing the conception that this literature exposed about brain physiology and its "accidents", identifying the diseases most included and exploring the body map that these conceptualizations suggest. It shows that brain diseases were in close relation to vapors and humors coming from other parts of the body, connections that can also be found in narratives from people not related to medicine. Thus, it suggests the existence of a confluence between medical and lay languages.