Neuroscience Trivia
0Loading crowd target
0Loading crowd target
6correct to beat the crowd
98 free Neuroscience trivia questions with answers — science & nature quiz, new questions added Oct 2026.
42 free Neuroscience trivia questions with answers. Neuroscience trivia tends to stop at 'the brain has 86 billion neurons'. This quiz goes further, into how those neurons actually work and how we found out: the squid axon that gave Hodgkin and Huxley their model, the dream that told Otto Loewi how nerves talk to each other, the staining method Golgi discovered and Cajal used against him, the railway foreman with a rod through his skull, and the patient known as H.M. who could not make new memories. It covers anatomy (cerebellum, hippocampus, amygdala, corpus callosum, Broca's area), chemistry (dopamine, serotonin, acetylcholine, botulinum toxin, tetrodotoxin), methods (EEG, optogenetics, the C. elegans connectome) and the oddities of the mind, from face blindness to split-brain patients arguing with their own hands. Roughly a third of the questions are easy enough for a curious teenager; the rest climb toward the Nobel Prize citations. Every answer was checked against Wikipedia's articles on the relevant structure, molecule or scientist, and each question carries its source.
30 of 98 questions with answers and explanations. Play the quiz
Q 01Roughly how many neurons does the adult human brain contain?
86 billion
86 billion: a 2009 count that replaced the round 100 billion textbooks had long quoted, and found about as many non-neuronal cells again, not ten times more.
Q 02The brain uses roughly what share of the body's energy?
About 20%
About 20%: the brain makes up only about 2% of body weight, yet it burns a fifth of the body's energy, more than any other organ.
Q 03The electrical signals neurons fire are called what?
Action potentials
Action potentials last only a few thousandths of a second in a neuron, and they are not unique to animals: a Venus flytrap snaps shut when touch sets off the same kind of pulse.
Q 04Which two groups of animals get by with no neurons at all?
Sponges and placozoans
Sponges and placozoans: a sponge filters water without a single nerve cell, yet its genome already holds most of the genes other animals use to wire nerve cells together.
Q 05The junction across which one neuron signals to another cell is called what?
A synapse
A synapse: the word dates from 1897 and comes from the Greek for 'to clasp together', coined while scientists were still arguing over whether nerve cells were separate units at all.
Q 06The fatty sheath that insulates axons and speeds up conduction is called what?
Myelin
Myelin: in multiple sclerosis the immune system strips it from nerve fibres, and signals that once raced along them slow down or fail.
Q 07Which glial cells wrap axons in their insulating sheath inside the brain and spinal cord?
Oligodendrocytes
Oligodendrocytes: each one wraps stretches of several different axons at once, whereas a Schwann cell, its counterpart in the body's other nerves, wraps just one.
Q 08Which part of the brain, only about a tenth of its volume, holds roughly four in five of its neurons?
The cerebellum
The cerebellum: its tiny, densely packed granule cells outnumber all the neurons of the far larger cerebral cortex by about four to one.
Q 09The memory-forming structure deep in the temporal lobe is named after its resemblance to which animal?
A seahorse
A seahorse: Arantius, the anatomist who first described the curled ridge in 1587, also offered 'white silkworm' as a name, but the fish won.
Q 10Which limbic structure, named from the Greek for 'almond', is central to processing fear?
The amygdala
The amygdala: a woman known as S.M., whose amygdalae were destroyed by a rare disease, handled live snakes and toured a haunted house without showing fear.
Q 11The thick fibre bundle that links the two cerebral hemispheres is found only in which group of animals?
Placental mammals
Placental mammals: kangaroos, koalas and the platypus have no such bundle, and link the two halves of the cortex through an older tract, the anterior commissure, instead.
Q 12Broca's area, linked to speech production, sits in which part of the brain?
The frontal lobe
The frontal lobe: Paul Broca's most famous patient, a man nicknamed Tan who had almost entirely lost the power of speech, was found to have an injury at the back of that lobe.
Q 13Which lobe of the cerebrum is dedicated to vision?
Occipital
Q 21Dopamine is nicknamed the pleasure chemical, but researchers now tie it mainly to what?
Motivation
Motivation: dopamine marks what is worth wanting and working for; rats drained of almost all their dopamine still showed normal pleasure at a sweet taste.
Q 22About 90% of the body's serotonin is made where?
In the gut
In the gut: cells lining the intestines make it to keep food moving, and because it cannot pass from the blood into the brain, the brain has to make its own small supply.
Q 23Botulinum toxin causes flaccid paralysis by blocking the release of a chemical messenger where?
At the neuromuscular junction
Occipital: it sits at the very back of the head, and damage there can leave a person blind even though both eyes still work.
Q 14Phineas Gage survived an 1848 accident in which what passed through his head?
A tamping iron
A tamping iron: the metre-long rod went in through his left cheek and out through the top of his head; he lived nearly twelve more years, and for a time friends said he was 'no longer Gage'.
Q 15Patient H.M. lost the ability to form new memories after 1953 surgery removed most of which brain structure?
The hippocampus
The hippocampus: Henry Molaison could still master a tricky mirror-drawing skill over a few days, yet never remembered having practised it.
Q 16Which two rivals shared the 1906 Nobel Prize for work on the structure of the nervous system?
Golgi and Ramón y Cajal
Golgi and Ramón y Cajal never agreed: Golgi's own silver stain let Cajal show that nerve cells are separate units, a theory Golgi still rejected when they shared the prize.
Q 17Santiago Ramón y Cajal, the doctor who had wanted to be an artist, came from which country?
Spain
Spain: his father, an anatomy professor, steered the would-be artist into medicine, and Cajal put his draughtsmanship to work at the microscope.
Q 18Hodgkin and Huxley worked out how nerve impulses propagate using which animal's giant axon?
The squid
The squid: its giant nerve fibre, about half a millimetre across and nearly a thousand times thicker than ours, was wide enough to take an electrode inside.
Q 19Otto Loewi's Nobel-winning proof that nerves signal chemically came to him how?
In a dream
In a dream: he woke, jotted the idea down and went back to sleep, then found he couldn't read his note; when the dream came back the next night, he went straight to his lab.
Q 20Which neurotransmitter do motor neurons release to make muscles contract?
Acetylcholine
Acetylcholine: in myasthenia gravis the body's own antibodies block the muscles' receptors for it, so muscles tire and weaken quickly with use.
At the neuromuscular junction: a nerve ending that cannot release its messenger leaves the muscle limp, and in tiny injected doses the same effect smooths wrinkles for a few months.
Q 24Tetrodotoxin takes its name from the scientific name of which fish?
Pufferfish
Pufferfish: the toxin is named after the genus Tetraodon, 'four teeth', and blocks the sodium channels nerves need to fire, which is what makes badly prepared fugu deadly.
Q 25The blood-brain barrier is formed mainly by which type of cell?
Endothelial
Endothelial: the cells that make up brain capillary walls are sealed together so tightly that most drugs cannot pass, a standing obstacle to treating brain disease.
Q 26Roughly how much cerebrospinal fluid does the human body produce each day?
About 500 mL
About 500 mL: only about 150 mL is in circulation at any moment, so the whole supply is replaced roughly four times a day.
Q 27The glymphatic system, which flushes waste from the brain, is thought to work hardest during what?
Slow-wave sleep
Slow-wave sleep: in sleeping mice the gaps between brain cells widened by about 60%, letting fluid wash through faster, though a 2024 study has challenged the finding.
Q 28Mirror neurons were first recorded in the premotor cortex of which animal, by Rizzolatti's team in Parma?
The macaque monkey
The macaque monkey: the team was recording cells that control grasping when they found that many also fired as the animal merely watched an experimenter pick up food.
Q 29Which husband-and-wife team discovered grid cells in the brain in 2005?
Edvard and May-Britt Moser
Edvard and May-Britt Moser found cells that fire at the corners of a repeating grid of triangles as a rat crosses a room, a built-in coordinate system that won them a 2014 Nobel Prize.
Q 30Place cells fire when an animal is in a particular spot; collectively they are thought to form what?
A cognitive map
A cognitive map: the phrase comes from Edward Tolman, who argued in 1948 that rats learn the layout of a maze, and place cells, first recorded in 1971, gave the idea a physical basis.