Neurobiology Brief History

The history of neurology is a fragmented one fraught with disagreements and centuries of stagnation. The earliest evidence of brain surgery dates back to prehistoric skulls with the marks of trepanation and subsequent recovery. Ancient Egyptians suggested that the heart was the seat of the soul rather than the brain. After that, the Ancient Greeks discovered the separation between the central nervous system (CNS) and peripheral nervous system (PNS), though opinions were split as to whether the brain matter actually served a purpose in consciousness. Later, in 200BCE, Galen of Ancient Rome discovered cerebrospinal fluid in sheep and concluded that it was this liquid that gave rise to the conscious mind. Records of brain research in the Orient end there for nearly 1700 years, until the Renaissance in the 16th century. Leonardo da Vinci picks up the study of brain anatomy and makes detailed drawings of the brain and its ventricles. Slightly later in the mid 1500s, Andreas Vesalius dissects the bodies of executed prisoners and refutes Galen’s hypothesis that CSF is the seat of consciousness, rather, the solid matter gives rise to the mind. However, in the 1600s, Descartes counters this hypothesis in saying that the mind and brain are separate entities, giving birth to philosophical dualism. But, around the same time, Thomas Willis and Christopher Wren dissect human bodies and come to the same conclusion as Vesalius, the wellspring of the mind is not CSF but brain matter. Many small discoveries over the next centuries resulted in our understanding that nerves communicate via electricity and that different parts of the brain are important for different functions. It was only in the early 1900s that neurons were stained (Camillo Golgi) and then hypothesized to be the individual units of the brain (Santiago Ramón y Cajal). Finally, as we approach the 21st century, research has brought to light the existence of different neuron types, and other classes of brain cells - such as glia - that serve a host of other purposes in maintaining brain function. Though we know much about the anatomy of the brain, we are still in the dark about its generation, possible regeneration, information processing capabilities, and how it gives rise to consciousness.