The history
8,500 years from holes in skulls to a count of 86 billion neurons.
For most of history people argued about whether we think with the heart or the head. Surgeons, anatomists, doctors and patients slowly proved it is the brain, then found its parts, its cells, its electricity and its chemistry. Today scanners watch it work, and there is still far more to learn.
c. 6500 BCE
Oldest known brain surgery
Neolithic trepanation, France
c. 1600 BCE
First written description of the brain
Edwin Smith Papyrus, Egypt
1664
The word “neurology”
Thomas Willis, England
1924
First human EEG
Hans Berger, Germany
1949
First neurosurgery department in India
Jacob Chandy, Vellore
1990
First fMRI (BOLD) images
Seiji Ogawa, USA
6500 BCE – 250
Stone Age surgeons open skulls, an Egyptian papyrus describes the brain, and Greek doctors argue that the mind lives in the head, not the heart.
6500 BCE
c. 6500 BCE
Some of the oldest known holes cut into living people’s skulls come from Neolithic graves in France. At one site, about a third of the skulls had been trepanned. Many show healed bone, so patients often survived.
Why it mattered. It is the oldest known brain surgery, though we can only guess why it was done.
1600 BCE
c. 1600 BCE
The Edwin Smith Papyrus, a copy of an even older surgical text, describes 48 injury cases. It contains the first known descriptions of the brain’s surface, its coverings and the fluid around it, and notes that head injuries can paralyse the body.
Why it mattered. It links the brain to control of the body more than 3,500 years ago.
500 BCE
c. 500 BCE
The Greek thinker Alcmaeon is credited with arguing that the senses connect to the brain and that the brain is where we understand. Only fragments of his work survive, so this is attributed to him by later writers.
Why it mattered. It is one of the earliest known claims that thinking happens in the head.
400 BCE
c. 400 BCE
The Hippocratic text On the Sacred Disease says epilepsy is not a curse from the gods but a disorder of the brain. It says that joy, sorrow, thought and madness all come from the brain.
Why it mattered. It treated the brain, not the heart or the gods, as the source of the mind and its illnesses.
170
c. 160–180 CE
The physician Galen showed in public experiments that cutting certain nerves in the neck silenced a pig’s squeal while it kept breathing. He argued that the brain, through the nerves, controls the voice and the muscles.
Why it mattered. His ideas, right and wrong, guided medicine for about 1,400 years.
1540 – 1850
Anatomists draw the brain accurately for the first time, give neurology its name, and find that nerves run on electricity.
1543
Vesalius’s book De humani corporis fabrica showed the brain in detailed woodcuts made from human dissections. He corrected many of Galen’s errors, which had come from studying animals.
Why it mattered. It made careful observation, not old books, the basis of anatomy.
1664
Willis’s Cerebri Anatome was the most detailed study of the brain yet. It introduced the term neurology and described the ring of arteries at the base of the brain, still called the circle of Willis.
Why it mattered. It placed functions like memory and movement in the brain’s tissue rather than its hollow ventricles.
1791
Galvani found that touching a frog’s nerve with metals, or with an electric spark, made its leg muscles twitch. He published his results in 1791 and argued that nerves carry a kind of animal electricity.
Why it mattered. It began the science of electricity in nerves, the basis of every spike.
1845 – 1960
Injured and ill patients reveal that different parts of the brain have different jobs, and surgeons map them. Hospitals for the brain and mind open, including in India.
1847
The Bangalore Lunatic Asylum opened in 1847. It was renamed the Mental Hospital in 1925 and later grew into one of India’s leading institutes for the brain and mind.
Why it mattered. It is the root of NIMHANS, India’s national institute for mental health and neurosciences.
1848
13 September 1848
A tamping iron blasted through the left frontal lobe of railway foreman Phineas Gage. He survived and could walk and talk, but his doctor reported that his personality changed. Historians now think he later recovered much of his social skill.
Why it mattered. His case suggested the frontal lobes shape behaviour and self-control.
1861
Broca examined the brain of a patient, Louis Leborgne, who could understand speech but say only one syllable, “tan”. He found damage in the left frontal lobe, the area now called Broca’s area.
Why it mattered. It was strong evidence that particular brain areas have particular jobs.
1874
Wernicke described patients who spoke fluently but made little sense and struggled to understand others. The damage was in the left temporal lobe, in what is now called Wernicke’s area.
Why it mattered. It showed that language relies on connected areas, not a single spot.
1937
During epilepsy surgery on awake patients, Penfield gently stimulated the cortex with electricity and asked what they felt. He mapped the body along the motor and touch strips, later drawn as the homunculus.
Why it mattered. His maps showed the crossed, distorted body plan in the cortex, with huge hands and lips.
1949
1949–1950
Jacob Chandy, trained under Penfield in Montreal, started India’s first neurology and neurosurgery department at Christian Medical College, Vellore, in 1949. In 1950 B. Ramamurthi set up the neurosurgery department in Madras. Both trained generations of Indian neurosurgeons.
Why it mattered. They built brain surgery in India almost from scratch.
1953
To treat severe epilepsy, surgeon William Scoville removed much of both of Henry Molaison’s hippocampi. Afterwards he could not form new lasting memories of events, though he could still learn skills. Psychologist Brenda Milner and others studied him for decades.
Why it mattered. His case showed that the hippocampus is key to forming new memories.
1870 – 1980
Stains reveal single neurons, and scientists discover synapses, brain waves, the spike, chemical messengers, and how learning changes connections.
1873
Golgi found that silver nitrate stains a few nerve cells completely black, showing every branch. For the first time, single neurons could be seen whole under a microscope.
Why it mattered. His stain made it possible to study the brain one cell at a time.
1888
Using an improved version of Golgi’s stain, Cajal showed that nerve cells are separate units that nearly touch, not one continuous net. His thousands of drawings still appear in textbooks.
Why it mattered. The neuron doctrine is the foundation of modern neuroscience.
1897
Sherrington introduced the word synapse, from Greek for “to clasp”, for the junction where one neuron passes a signal to the next. He went on to show how nerve signals add up and hold each other back.
Why it mattered. It named the place where almost all brain computing happens.
1906
Golgi and Cajal shared the Nobel Prize for their work on the structure of the nervous system. In their lectures they still disagreed: Golgi defended a continuous net, Cajal separate neurons. Cajal was right.
Why it mattered. It crowned the discovery of the neuron as the brain’s basic unit.
1921
Loewi said an experiment came to him in a dream. Fluid from a frog heart slowed by its vagus nerve also slowed a second heart. Nerves must release a chemical, later identified as acetylcholine.
Why it mattered. It proved that nerves talk to other cells with chemicals: neurotransmitters.
1924
Berger recorded tiny electrical waves from a person’s scalp, the first human electroencephalogram (EEG). He hesitated for five years and published in 1929. The rhythm he saw with eyes closed is the alpha wave.
Why it mattered. EEG let doctors watch the living brain’s activity, including in sleep and epilepsy.
1949
In his book The Organization of Behavior, Hebb proposed that when one cell repeatedly helps fire another, the connection between them grows stronger. The phrase “cells that fire together wire together” came later as a summary.
Why it mattered. It gave a cell-level idea of how learning could work.
1952
Working with the giant nerve fibre of the squid, Hodgkin and Huxley measured how sodium flowing in and potassium flowing out create the action potential. Their equations predicted the spike’s shape and speed. They shared the 1963 Nobel Prize with John Eccles.
Why it mattered. It explained the nerve impulse in the language of physics.
1953
Watching sleepers’ eyes and brain waves, Aserinsky and Kleitman found regular periods of rapid eye movement with an active, awake-looking EEG. People woken from them often reported vivid dreams.
Why it mattered. It showed that sleep has distinct stages, and that the brain is busy during it.
1959
Hubel, from Canada, and Wiesel, from Sweden, recorded single neurons in the visual cortex and found each fired for lines at a particular angle. Vision is built up from simple features. They shared the 1981 Nobel Prize.
Why it mattered. It showed how the visual cortex turns light into shapes, step by step.
1973
Stimulating a pathway into a rabbit’s hippocampus with rapid bursts made its synapses respond more strongly for hours or longer. This long-term potentiation (LTP) is a leading cellular model of learning and memory.
Why it mattered. It found in real tissue the kind of change Hebb had predicted.
1970 – today
Scanners show the working brain without surgery, neurons are finally counted, and big projects map its wiring.
1974
27 December 1974
The Bangalore mental hospital and the All India Institute of Mental Health became the National Institute of Mental Health and Neurosciences, an autonomous institute. It became a deemed university in 1994 and an Institute of National Importance in 2012.
Why it mattered. It became a major centre for brain research, treatment and training in India.
1990
Ogawa showed that MRI can detect changes in blood oxygen in the brain, the BOLD signal. Busy brain areas get extra oxygen-rich blood, so scanners can map which parts work during a task. This became functional MRI.
Why it mattered. fMRI lets scientists watch healthy human brains at work without surgery.
1996
Indian-born neuroscientist V. S. Ramachandran used a simple box with a mirror to let people see a reflection of their missing arm moving. For some, feelings in the phantom limb changed, and some felt it move.
Why it mattered. It became a famous demonstration that the brain’s body map can change: neuroplasticity.
2009
Herculano-Houzel’s team dissolved brains into a soup of cell nuclei and counted them. Four adult male brains held on average about 86 billion neurons and a similar number of other cells, not the 100 billion neurons and ten times more glia often quoted.
Why it mattered. It replaced a guessed number with a measured one.
2009
2009–2010
The NIH launched the Human Connectome Project in 2009 and funded two research groups in 2010. They scanned over a thousand healthy adults to map the brain’s connections, and shared the data freely.
Why it mattered. Open maps of brain wiring now support research worldwide.
By the numbers
Whole-brain neuron counts from Herculano-Houzel’s lab, placed at the year each was published. A human brain has over 1,000 times as many neurons as a mouse brain.
Did you know?
About 69 of your 86 billion neurons are in the cerebellum, the small “little brain” at the back.
Your brain is about 2% of your body weight but uses about 20% of its energy at rest.
The cortex is only 2 to 4 mm thick; folding lets a large sheet fit inside the skull.
The brain itself has no pain sensors, which is why surgeons like Penfield could operate on awake patients.
“We only use 10% of our brain” is a myth: scans show activity all over the brain.
The people
1852 – 1934 · Neuroanatomist · Spain
Showed that the brain is made of separate neurons, and drew them beautifully.
born 1918 · Neuropsychologist · England and Canada
Her decades of work with H.M. helped found the modern science of memory.
1926 – 2008 · Research participant · USA
Helped the world understand memory by taking part in studies for over 50 years.
1910 – 2007 · Neurosurgeon · India
Founded India’s first neurology and neurosurgery department at CMC Vellore in 1949.
1922 – 2003 · Neurosurgeon · India
Built neurosurgery in Madras from 1950 and later led the World Federation of Neurosurgical Societies.
born 1972 · Neuroscientist · Brazil
Invented a way to count brain cells and found about 86 billion neurons.
1891 – 1976 · Neurosurgeon · USA and Canada
Mapped the cortex of awake patients and inspired the homunculus.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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