10 amazing facts about the brain


1. Your brain has about 100 billion neurons – about as many stars as in the Milky Way galaxy

Each of these neurons is connected to hundreds or thousands of others by synapses. These connections are not fixed – they can change with experience, allowing us to learn.

2. Because of a property called neuroplasticity, the brain is constantly changing in response to experience

Neuroplasticity is one of the brain’s most important properties, as it lets us learn and adapt to our environment. Plasticity can occur in many ways: synapses – the junctions between neurons – can change strength (a bit like changing the volume of a conversation), new synapses can appear or disappear, and in some parts of the brain, brand new neurons can be born.

3. Our brains continue to produce new neurons throughout our lifespan

This process is called neurogenesis, but it only occurs in certain parts of the brain. In humans, these include the hippocampus – an important memory structure – and the striatum, which plays diverse roles in movement and reward processing.

4. Signals in your neurons can travel at the same speed as Formula 1 cars (~100 m/s or 360 km/h)

These signals, called action potentials, are necessary for neurons to communicate with each other. The 1963 Nobel Prize was awarded for work done to understand how action potentials are generated.

5. Left-brain and right-brain dominance is a myth

While some brain areas are used more than others for particular functions, and these can be on the left or right side (for example, language processing occurs mostly on the left side), no one side of the brain is used more than the other.

6. Some animals can regrow injured neurons

While humans can’t regenerate nerves of the central nervous system, animals like worms can. Researchers are studying how this happens with the hope of discovering a way to help people with spinal cord injury.

7. Your brain is hyper-efficient, running on just 20 watts of power

A computer, by contrast, needs 65–250 W, and for a computer to simulate the 100 trillion connections of the human brain in real-time, it would need 12 gigawatts – around 600 million times the power!

8. We don’t just use 10% of our brains

Some areas are more active than others at any given moment, but all of our brain gets used. In fact, the brain is the most energy-intensive part of our body, using 20% of our energy even though it makes up just 3% of our weight.

9. Dementia is not a single disease

Instead, dementia is an umbrella term that describes a collection of symptoms. These symptoms are caused by deterioration of brain tissue, which is normally caused by a build-up of toxic proteins. Over 50 conditions are known to cause the symptoms of dementia.

10. Not all brain cells are the same

Your 100 billion neurons come in all shapes and sizes, and these different types of neuron do different jobs. On top of this, you have at least as many non-neuronal cells (called glia) as you do neurons. Glia nourish, support and help protect neurons from damage, and even play important roles in neuron–neuron communication.

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