Part Four of The Renaissance Brain Mini-Series.
Part Three can be found here: http://www.examiner.com/science-news-in-allentown/cerebrum-renatus-renaissance-brain-iii-michelangelo
Galen was a Greek physician in the second century AD. His views of the brain were propagated throughout the centuries, even holding out like a bulwark during the intense period of the Renaissance. Galen circulated the idea that the brain and its nerves were responsible for muscular movement. He still held on to the belief, however, that animal spirits resided in the ventricles. Galen also believed that the ventricles, which are filled with cerebrospinal fluid, corresponded to the idea that the human body operated according to the levels and balances of four humors: blood, phlegm, and yellow and black bile (Neuroscience: Exploring the Brain). During Galen’s time was the idea of ventricular localization, that is, the ventricles of the brain each had a psychological or physiological role in the workings of the brain (Finger, 1994). Galen’s view on anatomy hindered growth of anatomical understanding during the early Renaissance, since his views were considered the authoritative source of such knowledge and no one initially considered reviewing his work to verify his ideas (Pevsner, 2002). Vesalius (1514-1564), however, an anatomist and physician during the 1500s, both drew upon and criticized the work of Galen. He studied anatomy by dissecting corpses from cemeteries and execution sites. Vesalius criticized the prevailing theory of ventricular localization. He argued that animals other than humans possessed ventricles of similar shape and size to human brain ventricles, and these same non-human animals did not have the same mental capacity as humans. Therefore, he concluded, the ventricles are not the seat of cognition and higher-order faculties (Finger, 1994). Galen’s work, long upheld through the centuries, was criticized by Vesalius. It is, in part, due to Vesalius, who urged scientists and philosophers to re-examine Galen’s work, that the field of neuroscience could begin heading toward a direction of enlightenment. However, Vesalius still upheld the belief that the brain’s ventricles were the origin of ‘animal spirits’. He believed that the ventricles were cavities in which air inhaled by an individual mixed with the heart’s fluids, and through the brain, were transformed into animal spirits (Finger, 1994). This belief, though strange today, was resonant with the prevailing theory of Vesalius’ time that animal spirits and a soul animated the human body, and the brain was the seat of the soul. Vesalius, however, still believed that the brain was the seat or intellect, movement, and sensation.
Finger, Stanley. Origins of Neuroscience: A History of Explorations into Brain Functions. New York, USA: Oxford University Press: 1994.
Pevsner, Jonathan (2002). Leonardo da Vinci’ contributions to Neuroscience. TRENDS in Neuroscience, 25, 217-220.
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