The Brain Trivia
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100 free The Brain trivia questions with answers — science & nature quiz, new questions added Oct 2026.
The brain weighs about as much as a bag of sugar, has the consistency of soft tofu, and burns a fifth of everything you eat. Aristotle thought it was a radiator for the blood. Descartes put the soul in its pine-cone-shaped gland. A Vermont railroad foreman took an iron bar through it and lived twelve more years. These 100 questions cover what a classroom or a pub round needs: the three main parts, the four lobes and what each does, the cortex and its folds, the corpus callosum, what 'cerebellum' means, the brainstem's job, the seahorse-shaped memory centre, the almond of fear, the hypothalamus and pineal gland, the three meninges and their Latin names, cerebrospinal fluid, the blood-brain barrier and the dye that revealed it, myelin and the nodes of Ranvier, neurons and synapses, Broca's area, Phineas Gage, H.M., Hans Berger's first EEG, Golgi and Cajal, phrenology, the ten percent myth and the brain that turned to glass at Vesuvius. Easy questions ask which lobe sees; hard ones ask who first called the brain the seat of the mind. Every answer is cited to a page we checked, with a short explanation so you learn something even when you miss. Play it solo or print it for a biology class.
30 of 100 questions with answers and explanations. Play the quiz
Q 01What are the three main parts of the human brain?
Cerebrum, brainstem, cerebellum
Cerebrum, brainstem, cerebellum. The cerebellum takes up only about a tenth of the brain's volume, yet it holds more neurons than the rest of the brain combined.
Q 02Roughly how much does an adult human brain weigh?
About 1.3 kg
About 1.3 kg. Albert Einstein's brain weighed 1,230 grams, a little lighter than the average man's.
Q 03About how many neurons are in the human brain?
86 billion
86 billion. Suzana Herculano-Houzel reached the figure by dissolving donated brains into a 'soup' and counting the nuclei; textbooks had long said 100 billion.
Q 04The brain uses about what share of the body's energy at rest?
20%
20%. Hard thinking barely raises it: the brain burns nearly as much energy at rest as it does on a difficult problem.
Q 05What is the main fuel the brain normally runs on?
Glucose
Glucose. The brain needs a constant supply of it from the blood, which is why a steep fall in blood sugar can cause loss of consciousness.
Q 06The brain's four main lobes take their names from what?
Skull bones
Skull bones. Each lobe is named for the bone lying over it, but the match is only rough: the lobes are divided by grooves in the brain's surface, not by the seams of the skull.
Q 07Which lobe is dedicated to vision?
Occipital
Occipital. Damage to this lobe on both sides can cause cortical blindness, in which the eyes are healthy but the brain can no longer see.
Q 08Parkinson's disease follows the loss of brain cells that make which chemical messenger?
Dopamine
Dopamine. The cells that make it sit in a region called the substantia nigra, and movement symptoms appear only after more than half of them are already lost.
Q 09What is the outer grey-matter layer of the cerebrum called?
Cerebral cortex
Cerebral cortex. It is only 2 to 4 mm thick, so it folds deeply to fit more grey matter inside the skull.
Q 10What are the ridges and grooves on the brain's surface called?
Gyri and sulci
Gyri and sulci. Mice and rats have none: their brains stay smooth, which in a human is a rare and serious condition called lissencephaly.
Q 11What does the corpus callosum do?
Connects the two hemispheres
Connects the two hemispheres. Kim Peek, the savant who inspired Rain Man, was born without one, and some people who lack it show no detectable problems at all.
Q 12What does the Latin name 'cerebellum' mean?
Little brain
Little brain. The name undersells it: scans show that its tightly pleated surface, unfolded, has almost 80 percent as much area as the surface of the cerebrum.
Q 13The cerebellum is best known for its role in what?
Motor coordination
Motor coordination. It does not start a movement but fine-tunes its timing and precision, so damage leaves a person able to move yet clumsy and unsteady.
Q 21Which philosopher called a small gland deep in the brain 'the principal seat of the soul'?
René Descartes
René Descartes. His reason was that he could find no other part of the brain 'which is not double', so this single gland had to be where our thoughts come together.
Q 22What are the three protective membranes around the brain and spinal cord called?
Meninges
Meninges. When an infection inflames these membranes the illness is meningitis, whose warning signs include a severe headache and a stiff neck.
Q 23What does 'dura mater', the name of the brain's outermost membrane, mean in Latin?
Tough mother
Tough mother. The Latin is a medieval translation of an Arabic phrase, 'thick mother of the brain'; Arabic often uses family words for the relationships between things.
Q 14Which three structures make up the brainstem?
Midbrain, pons, medulla
Midbrain, pons, medulla. The pons, Latin for bridge, earns its name as the main link between the cerebellum and the rest of the brainstem.
Q 15The centres that control breathing and blood pressure sit mainly in which brain structure?
Medulla
Medulla. It sits where the brain meets the spinal cord and works without conscious effort, which is why you keep breathing in your sleep.
Q 16The hippocampus takes its name from its resemblance to which animal?
Seahorse
Seahorse. The 16th-century anatomist Arantius, the first to describe it, wavered between a seahorse and a white silkworm; the seahorse stuck.
Q 17The hippocampus is most important for which function?
Consolidating long-term memory
Consolidating long-term memory. London taxi drivers, who must memorise the city's streets to earn a licence, were found to have a larger rear hippocampus than other people.
Q 18The amygdala is most associated with processing which of these?
Fear and emotion
Fear and emotion. A woman known as S.M., whose amygdalae were destroyed by a rare disease, showed no fear when handed snakes or led through a haunted house.
Q 19Which structure links the nervous system to the endocrine system via the pituitary?
Hypothalamus
Hypothalamus. It is also the body's thermostat: a fever begins when it resets itself to a higher temperature.
Q 20Which gland produces melatonin, the hormone that helps regulate sleep?
Pineal gland
Pineal gland. Named from the Latin for pine cone, after its shape, it makes melatonin in darkness, and light reaching the eyes suppresses it.
Q 24The middle membrane around the brain is named for its resemblance to what?
A spider web
A spider web. It is the arachnoid mater, from the Greek for cobweb, after the fine web-like fibres that cross the fluid-filled space beneath it.
Q 25Why can surgeons operate on the brain while the patient is awake and talking?
Brain tissue has no pain receptors
Brain tissue has no pain receptors. Keeping the patient awake lets the surgeon test each spot first and steer around any area where speech or movement falters.
Q 26The fluid-filled chambers deep in the brain, where cerebrospinal fluid is made, are called what?
Ventricles
Ventricles. If the fluid cannot drain away it builds up and the chambers widen, pressing on the brain, a condition called hydrocephalus.
Q 27Neurosurgeon Katrina Firlik likened the feel of the living brain to what?
Soft tofu
Soft tofu. She rejected her colleagues' comparison to toothpaste, noting that a cut cube of brain holds its shape, 'although not quite as well as tofu'.
Q 28The blood–brain barrier is formed by the tightly sealed walls of which vessels?
Capillaries
Capillaries. Their wall cells are joined so tightly that germs in the blood are kept out of the brain, but so are most drugs, a major hurdle in treating brain diseases.
Q 29Which scientist, who coined 'magic bullet', found that some injected dyes failed to stain the brain?
Paul Ehrlich
Paul Ehrlich. He put it down to brain tissue having little affinity for those dyes; Edwin Goldmann later showed that dye injected into the spinal fluid stained the brain after all.
Q 30What is the fatty material that insulates axons and speeds up nerve impulses?
Myelin
Myelin. In multiple sclerosis the immune system attacks it, and the stripped nerve fibres can no longer carry their signals properly.