50 Fun Facts About The Brain

What are the three main parts of the human brain?

Together with the spinal cord it forms the central nervous system.

Roughly how much does an adult human brain weigh?

That is about 2 percent of body weight, yet it uses up to 20 percent of the body's energy.

About how many neurons are in the human brain?

There are roughly as many supportive glial cells as neurons.

The brain uses up to what share of the body's energy?

It also takes about 20 percent of the oxygen and a quarter of the glucose.

What is the main fuel the brain normally runs on?

During fasting it can switch to ketone bodies; low blood sugar can cause loss of consciousness.

How many lobes is each cerebral hemisphere conventionally divided into?

Frontal, parietal, temporal and occipital, named after the skull bones above them.

Which lobe is dedicated to vision?

Its name comes from Latin for 'behind the head'; damage to both sides can cause cortical blindness.

Which lobe handles executive functions such as planning, self-control and reasoning?

It is the largest lobe and sits furthest forward.

What is the outer grey-matter layer of the cerebrum called?

It is only 2 to 4 mm thick but deeply folded into ridges and grooves.

What are the ridges and grooves on the brain's surface called?

The central sulcus separates the frontal and parietal lobes.

What does the corpus callosum do?

It is about 10 cm long and carries 200 to 300 million axons.

What does the Latin name 'cerebellum' mean?

Its tightly folded cortex conceals a surface like an accordion.

The cerebellum is best known for its role in what?

It does not start movements but fine-tunes their precision and timing.

Which three structures make up the brainstem?

It is only about 2.6 percent of brain weight but regulates heart rate and breathing.

The vasomotor and respiratory centres that keep you breathing sit mainly in which structure?

Signals travel down the phrenic nerve to the diaphragm.

The hippocampus takes its name from its resemblance to which animal?

Venetian anatomist Aranzi likened it first to a silkworm, then a seahorse, in 1587.

The hippocampus is most important for which function?

It is also key to the spatial memory used in navigation.

The amygdala is most associated with processing which of these?

Karl Friedrich Burdach named the almond-shaped structure in 1822.

Which almond-sized structure links the nervous system to the endocrine system via the pituitary?

It also governs temperature, hunger, thirst, sleep and circadian rhythms.

Which brain structure produces melatonin and is shaped like a pine cone?

Descartes called it 'the principal seat of the soul'.

Which philosopher regarded the melatonin-producing gland as the seat of the soul?

He discussed it in Treatise of Man and The Passions of the Soul.

What are the three protective membranes around the brain and spinal cord called?

Dura mater, arachnoid mater and pia mater, from outside in.

What does 'dura mater', the toughest outer brain membrane, mean in Latin?

The delicate inner pia mater is 'tender mother'.

The middle meningeal layer is named for its resemblance to what?

The arachnoid mater is thin and transparent and cushions the central nervous system.

Roughly how much cerebrospinal fluid does a human produce each day?

Only about 125 mL is present at any one time; it acts as a shock absorber.

Where is most cerebrospinal fluid produced?

It is absorbed back into the blood through arachnoid granulations.

What is the living brain's consistency often compared to?

It is very soft and gel-like, which is why it is suspended in fluid inside the skull.

What is the selective border of capillary cells that shields neural tissue from the bloodstream?

It is formed by tightly joined capillary cells, astrocyte end-feet and pericytes.

Whose dye experiments in the late 1800s stained every organ except the brain?

His dyes stained every organ except the brain; his student Edwin Goldmann later reversed the experiment.

What is the fatty material that insulates axons and speeds up nerve impulses?

Gaps in it called nodes of Ranvier let the signal jump from node to node.

What are the gaps between the insulating segments on an axon called?

Each is about one micrometre long and enables saltatory conduction.

What is the electrical signal a neuron fires called?

Neurons pass the signal across synapses using chemical neurotransmitters.

What is the junction where one neuron passes a signal to another cell called?

Minute amounts of neurotransmitter cross the synaptic gap.

Which animals are the only ones with no neurons at all?

Plants and fungi have no nerve cells either; electric signalling arose 700 to 800 million years ago.

What are the brain's supportive non-neuron cells called?

There are about as many of them as there are neurons.

Language is usually associated with which hemisphere?

Visual-spatial ability is more associated with the right.

Broca's area, linked to speech production, is in which lobe?

Paul Broca identified it from two patients who lost the ability to speak.

Which railroad foreman survived an iron rod through his skull in 1848?

The tamping iron landed 80 feet away; friends said he was 'no longer Gage'.

The 1848 tamping-iron accident happened while blasting rock in which US state?

He was preparing the roadbed for the Rutland & Burlington Railroad near Cavendish.

Amnesia patient 'H.M.' could not form new memories after surgery removed most of what?

Henry Molaison's 1953 operation was meant to treat epilepsy; he was studied until his death in 2008.

Who recorded the first human EEG in 1924?

He also named the alpha wave, the first rhythm he observed.

EEG brain waves in the 8 to 12 Hz range are called what?

Hans Berger gave the first rhythm he saw that name.

Which two scientists are considered the founders of modern neuroscience?

Golgi's silver stain let Cajal propose the neuron doctrine; they shared a Nobel Prize.

Which ancient thinker thought the heart held intelligence and the brain cooled the blood?

He reasoned humans are rational because a bigger brain cools their hot blood better.

Who first called the brain the seat of the mind, in the fifth century BC?

The Hippocratic treatise On the Sacred Disease agreed around the same time.

What 19th-century pseudoscience mapped personality onto bumps of the skull and cortex?

It was hugely popular in the early 1800s.

Which common claim about the brain is a myth?

Research has also disproved the idea that neurons are never replaced after age two.

What was discovered in 2025 in the skull of a Vesuvius victim from AD 79?

Extreme heat from a pyroclastic flow vitrified it, the only known case.

What is the glymphatic system thought to do, especially during sleep?

Cerebrospinal fluid flows along blood vessels and flushes out waste, more so in slow-wave sleep.

Which 1942 science-fiction novel is about an isolated organ kept alive in a tank?

It was adapted for the cinema three times.