title: [The historical background of the pineal gland: I. From a spiritual valve to the seat of the soul].
abstract: BACKGROUND
  Throughout history, the special anatomical location of the pineal gland in the central nervous system has given rise to a number of physiological hypotheses regarding the functional role of this organ.
  
  
  METHODS
  In classical ancient times, the pineal body (conarium) was considered to be a sort of valve-like sphincter that regulated the flow of the spiritus animalis at the ventricular level. But it was not until the 17th century that the pineal gland finally reached its highest levels of physiological significance, when Rene Descartes considered it to be the anatomical structure that housed the seat of the soul.
  
  
  CONCLUSIONS
  The Cartesian hypotheses regarding the pineal gland did not arouse much interest in the scientific community of the time, and attention to this organ dwindled from then until the 20th century, when its neuroendocrinological nature was finally confirmed.
authors.affiliation: Departamento de Farmacología, Universidad de Alcalá, Facultad de Medicina, Alcalá de Henares, España. francisco.lopez.munoz@gmail.com
authors.forename: Francisco
authors.initials: F
authors.lastname: López-Muñoz
authors.forename: Fernando
authors.initials: F
authors.lastname: Marín
authors.forename: Cecilio
authors.initials: C
authors.lastname: Alamo
mesh_terms: D006666:History of Medicine; D049670:History, 17th Century; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049690:History, Ancient; D006801:Humans; D019222:Mind-Body Relations, Metaphysical / Q000502:physiology*; D009452:Neuroendocrinology; D009462:Neurology / Q000266:history*; D010870:Pineal Gland / Q000033:anatomy & histology / Q000502:physiology; D029181:Spirituality