History of neuroscience
During the second half of the first millennium BC, the Ancient Greeks developed differing views on the function of the brain. However, due to the fact that Hippocratic doctors did not practice dissection, because the human body was considered sacred, Greek views of brain function were generally uninformed by anatomical study. It is said that it was the Pythagorean Alcmaeon of Croton (6th and 5th centuries BC) who first considered the brain to be the place where the mind was located. According to ancient authorities, "he believed the seat of sensations is in the brain. This contains the governing faculty. All the senses are connected in some way with the brain; consequently they are incapable of action if the brain is disturbed...the power of the brain to synthesize sensations makes it also the seat of thought: The storing up of perceptions gives memory and belief and when these are stabilized you get knowledge." In the 4th century BC Hippocrates, believed the brain to be the seat of intelligence (based, among others before him, on Alcmaeon's work). During the 4th century BC Aristotle thought that, while the heart was the seat of intelligence, the brain was a cooling mechanism for the blood. He reasoned that humans are more rational than the beasts because, among other reasons, they have a larger brain to cool their hot-bloodedness.
Neuroscience
The view that the heart was the source of consciousness was not challenged until the time of the Greek physician Hippocrates. He believed that the brain was not only involved with sensation—since most specialized organs (e.g., eyes, ears, tongue) are located in the head near the brain—but was also the seat of intelligence. Plato also speculated that the brain was the seat of the rational part of the soul. Aristotle, however, believed the heart was the center of intelligence and that the brain regulated the amount of heat from the heart. This view was generally accepted until the Roman physician Galen, a follower of Hippocrates and physician to Roman gladiators, observed that his patients lost their mental faculties when they had sustained damage to their brains.