Our understanding of the brain has developed, as technology, culture and science has evolved.
The brain as a radiator
In 335 BC, Greek philosopher Aristotle thought the brain was simply a radiator that kept the all-important heart from overheating. Around 170 AD, Roman physician Galen suggested the brain’s four ventricles (fluid-filled cavities) were the seat of complex thought, and determined personality and bodily functions. This was one of the first suggestions that the brain was where our memory, personality and thinking reside.
First nervous system sketch
In the 16th century, Belgian anatomist Andreas Vesalius created a highly detailed map of the nervous system and argued against the ventricles as the site of brain functions. We now know he was correct: the ventricles are filled with the cerebrospinal fluid that nourishes brain cells and cushions the brain against physical impact.
Electricity fires the nerves
In 1791, in the first suggestion that electrical impulses were important in the nervous system, Italian Luigi Galvani showed that electricity applied to nerves could make muscles contract.
The brain has regions
In 1848, American railroad worker Phineas Gage had an iron rod strike his head, passing through his left frontal lobe. He survived, but aspects of his personality changed, suggesting that specific brain regions were important for certain functions. This idea grew stronger after studies in the 1860-70s by physicians Paul Broca and Carl Wernicke showed that specific parts of the brain were dedicated to different components of speech.
Neurons, units of the brain
In the early 1900s, anatomists were taking advantage of microscopes and new staining methods to explore the smallest parts of the brain. Neuroanatomists Santiago RamÓn y Cajal and Camillo Golgi were awarded the 1906 Nobel Prize for identifying that nerve cells (neurons) are the building blocks of the brain, and showing there are many different types.
Communication in the brain
In 1932 Sir Charles Sherrington and Edgar Adrian won the Nobel Prize for proposing the concept of synapses (junctions between neurons, pictured), which advanced the understanding of the central nervous system; Alan Hodgkin, Andrew Huxley and Australian Sir John Eccles won a Nobel Prize in 1963 for showing how neurons communicate via electrical and chemical signalling.
Explosion of neuroscience
From the 1960s there was an explosion of neuroscience research. With rapid advances in technology, and collaboration across fields such as physics and genetics, scientists have made great leaps in understanding the brain, through detailed imaging and mapping of networks (pictured), and deciphering chemical pathways.
