Each man is the architect of his own fate. ~ Galen
A few centuries after Aristotle, the Greek physician Galen (130–200) drew upon his extensive experience with animal disections, as well as his practice as gladiator physician, where he had the benefit of dealing with mangled combatants, including, no doubt, severe head and nerve injuries.
Galen corroborated Hippocrates: that the brain was the center of mental processing. Using the time-honored presumption that function follows form, Galen tried to deduce the respective processing of the cerebellum and the cerebrum.
Poking about revealed the cerebellum sinewy hard and the cerebrum a bit mushy. This led Galen to the conclusion that the cerebellum commanded the muscles, while the cerebrum was the recipient of sensations, which it stored.
To form memories, sensations must be imprinted. A doughy cerebrum fit.
Galen was not far off. The evolutionarily early cerebellum acts as a movement control center. The cerebrum is largely concerned with perception of sensations and memory.
Galen went further in his explorations, to mechanics. The prevailing theory at the time was that the body functioned according to a balance of 4 humors (vital fluids).
Galen’s dissections revealed the brain as floating in fluid, and having hollow sections, ventricles, like the heart, where blood is pumped throughout the body. So, Galen reasoned, sensations were registered, and movement initiated, by movement of humors to and from the brain through the nerves. Nerves were believed to be hollow tubes, like blood vessels.
Galen’s take on the brain prevailed for nearly 1,500 years. The concept of ventricular localization of brain function went unchallenged.