Ventricular theory

4th-5th century AD

During the middle ages, scholars and physicians believed that sense information from the five external senses (touch, taste, smell, hearing and sight) was transferred to the ventricles of the brain. The most widely accepted version of this ventricular theory was that the "common sense" or the sense that synthesized information from the all five senses was located in the front ventricle. It was in this ventricle that the information from the sense organs were said to combine into a unified perception.

Behind the front ventricle, through the vermis or passageway that connected the front with the middle ventricle was a storage space for representing previously perceived objects. The space was called the faculty of "imagination" or "representation." This faculty was divided into two subfaculties. In the first, the passive faculty, was a collection images of previously perceived objects. In the second, the active faculty, stored images could be recombined in new ways (e.g., fictitious objects).

An additional faculty in the middle ventricle was involved cognition by the medievalists. Cognitions were thought to be transferred to the rear ventricle for storage with the faculty of memory. Memory differed from the faculty of representation in that it was thought to store the results of estimation and cognition, whereas representation was thought to store only the "uninterpreted" images provided by the common sense. Occasionally a faculty of "volition" was hypothesized. It was placed at the rear of the third ventricle.

Avicenna (980-1037 AD), one of the earliest and best-known Medieval proponents of ventricular theory described information processing as follows:

One of the animal internal faculties of perception is the faculty of fantasy, i.e., sensus communis, located in the forepart of the front ventricle of the brain. It receives all the forms which are imprinted on the five [external] senses and transmitted to it from them. Next is the faculty of representation located at the rear part of the front ventricle of the brain, which preserves what the sensus communis has received from the five senses even in the absence of the sensed object. … Next is the faculty of the 'sensitive imagination' in relation to the animal soul, and the 'rational imagination' in relation to the human soul. This faculty is located in the middle ventricle of the brain near the vermiform process, and its function is to combine certain things with others in the faculty of representation, and to separate some things from others as it chooses. Then there is the estimative faculty located in the far end of the middle ventricle of the brain, which perceives the non-sensible intentions that exist in the individual sensible objects, like the faculty that judges that the wolf is to be avoided and the child is to be loved. Next there is the retentive and recollective faculty located in the rear ventricle of the brain, which retains what the estimative faculty perceives of the non-sensible intentions existing in individual sensible objects. (Avicenna, translated in Rahman 1952, p. 31)

Ventricular theory was an important concept from ancient times through the renaissance. Other primary proponents of the theory include:

Galen (129-201) depicted mental functions as being located in different places in the brain. He indicated that the functions could be affected independently by injury or disease. He did not identify specific places in the brain for these functions, however.

Nemesius (around 390 AD) was the Bishop of Emesa (today's Homs in Syria). He developed the fullest version of ventricular theory. Nemesius believed that the faculties operated through the agent of an animal spirit produced after it had been carried through a network of arteries. This network was referred as the Rete Mirabile and is located at the base of the brain. Nemesius' doctrine of Ventricle Localisation of Mental Functions was greatly acknowledged following its development, but it was later attacked.

Namesius elaborated on ventricular theory assigning different functions to each of the four ventricles in the brain. He placed perception and imagination in the two anterior lateral ventricles, cognition or intellectual abilities in the middle ventricle, and memory in the posterior ventricle.

Posidonius (4th century, A.D.) was a Greek philosopher, politician, astronomer, geographer, historian and teacher who lived in Syria—ancient Byzantium. He was a proponent of version of ventricular theory that assigned various psycholinguistic functions in the ventricles of the brain, with the front ventricle involving imagination, and the occipital ventricle being related to memory. Aphasia was seen as resulting from damage to the third ventricle (Tesak & Code, 2008, p. 15).

Ventricular theory continued to maintain a hold throughout the middle ages and into the renaissance. Fernel (1495-1558) a French physician and important founder of physiology, subscribed to a version of ventricular theory.

Writings about ventricular theory

Bennett, M. & Hacker, P. (2002). The motor system in neuroscience: a history and analysis of conceptual developments. Progress in Neurobiology, 67, 1, 1-52.

2. The ventricular doctrine: from Galen to Descartes

2.1. Galen: motor and sensory centers

2.2. Galen: the functional localization of the rational soul in the anterior ventricles

2.3. Nemesius: the formal attribution of all mental functions to the ventricles

2.4. One thousand years of the ventricular doctrine

2.5. Fernel: the origins of 'neurophysiology'

2.6. Descartes: the beginning of the end of the ventricular doctrine

Fernel, J. (1542/2005). Jean Fernel's on the hidden causes of things: Forms, souls, and occult diseases in renaissance medicine (Medieval and Early Modern Science) Translated by J. Forrester (2005). Brill Academic Publishers.

Finger, S. (1994). Origins of neuroscience: A history of explorations into brain function. Oxford, UK: Oxford University Press. (Chapter 2, pp. 18-20.

Green C.D. (2003). Where did the ventricular localization of mental faculties come from? Journal of the History of the Behavioral Sciences,39, 2, 131-142.

O'Neill, Y. V. (1993). Meningeal localization: A new key to some medical texts, diagrams, and practices of the middle ages. Mediaevistik, 6, 211-238.

Rahman, F. (1952). Avicenna's psychology. London: Oxford University Press.

Tesak, J. & Code, C. (2008). Milestones in the history of aphasia: Theories and protagonists. NY: Psychology Press.

Whitaker, H.A. (2007). Was medieval cell doctrine more modern than we thought? Chapter 4 in Henri Cohen & Brigitte Stemmer (Eds.). Consciousness and cognition: Fragments of mind and brain (pp 45-51). Elsevier.