1. A human brain weighs about 3.3lb (1.5kg) so accounts for about two per cent of body weight.
2. What used to be called the “grey matter” in our brains is composed of about 86 billion neurons (nerve cells); the “white matter” is axons and dendrites (nerve fibres).
3. The cells and fibres are connected by trillions of synapses.
4. Around 20 per cent of our total oxygen and energy intake is used by the brain.
5. Almost three quarters of the brain’s weight consists of water.
6. There is no clear correlation between brain size and intelligence. Neanderthals are thought to have had about 10 per cent larger brains than we do.
7. When Coca-Cola was first marketed in 1886 it was promoted as a “valuable Brain Tonic”.
8. In the 4th century BC Aristotle thought the brain was a cooling mechanism for the blood.
9. In 2010 it was discovered that flatworms can regenerate the heads and brains if they are cut off. Remarkably their memories also return.
10. “We are now all connected by the internet, like neurons in a giant brain,” (Stephen Hawking).
