ABSTRACT
Our understanding of how the brain functions has changed dramatically over the centuries. rough much of time, the heart was celebrated as the central locus of thought, emotions, and even the soul. e contents of the skull were regarded as an undierentiated biomass. While an ancient Egyptian papyrus-attributed to a battleeld surgeon-noted that head trauma aected physical function, there was no anatomical knowledge of the brain. In the rst century BC, Greek philosophers
theorized that the brain was where the mind was located and that it might be the seat of sensations. In the second century AD, the great Roman physician and anatomist Galen used dissection and produced detailed hand-drawn maps of the brain and the spinal cord. Galen believed that the soul and mind consisted of pneumo, or spirits emanating from the heart, and that the role of the brain was to ennoble these spirits in human beings. Galen’s “hydraulic” view of spirits moving around the body like uids was to dominate thinking into the Renaissance.2
