Neuroscience
54 questions tagged Neuroscience — spanning every one of the seven Ws.
Why do we dream?
Dreams occur primarily during REM sleep and may help consolidate memories, process emotions, and simulate threats. About 95% of dreams are forgotten within minutes of waking.
Why do we yawn?
The leading theory is brain thermoregulation — yawning cools the brain by stretching the jaw and increasing blood flow. Contagious yawning is linked to empathy and social bonding.
Why can't we remember being babies?
Most people cannot recall events before age 3–4, a phenomenon called infantile amnesia. The hippocampus, key to forming long-term memories, is still developing in early childhood.
Why does time seem to speed up as we age?
As we age, each year is a smaller fraction of our total life, and routine reduces novel memories. With fewer fresh markers, the brain compresses time, making years feel shorter.
Why do we experience déjà vu?
Déjà vu is the eerie feeling that a new moment has happened before. It likely stems from a brief glitch in how the brain processes memory.
How does the brain work?
The brain works through billions of nerve cells that pass electrical and chemical signals, forming the networks behind thought and memory.
Why Do We Get Dizzy?
Fluid in the inner ear keeps sloshing after you stop spinning, sending conflicting signals to the brain.
Why Do We Get Motion Sickness?
The brain receives mismatched signals from the eyes, inner ear, and body sensors about movement, triggering nausea.
Why Do We Forget Things?
Forgetting results from weakening neural connections, interference from other memories, and the brain prioritising important information.
How Does Anaesthesia Work?
General anaesthesia renders patients unconscious by disrupting neural signalling in the brain — anaesthetic drugs enhance inhibitory neurotransmission (mainly via GABA receptors) or block excitatory signalling, though the exact mechanism of unconsciousness is still not fully understood.
Why Do We See Colours?
We see colours because our eyes contain three types of cone cells, each sensitive to different wavelengths of light (red, green, blue), and our brain combines their signals to create the perception of millions of distinct colours.
Why Does Coffee Wake Us Up?
Caffeine blocks adenosine receptors in the brain — adenosine is a molecule that accumulates during waking hours and promotes sleepiness, so by blocking it, caffeine temporarily prevents the feeling of tiredness.
Why Does Time Seem to Speed Up as We Age?
Time feels faster as we age partly because each year becomes a smaller fraction of our total life, and partly because routine reduces the number of novel, memorable experiences the brain uses to gauge elapsed time.
Why Do We Yawn?
Yawning is thought to help cool the brain by increasing blood flow and drawing in cooler air; it may also boost alertness. Contagious yawning is linked to empathy and social bonding, though the exact purpose of yawning remains debated.
What is autism?
Autism is a lifelong neurodevelopmental difference that affects how people communicate, interact and experience the world. It is a spectrum, so it varies widely from person to person.
How Does Anaesthesia Make You Unconscious?
General anaesthetic drugs disrupt signalling between brain regions, suppressing consciousness, memory, and pain perception.
How Does Functional MRI Detect Brain Activity?
fMRI measures changes in blood oxygenation — active brain regions use more oxygen, altering the magnetic signal.
Why do our brains sleep instead of staying active all night?
Sleep helps the brain restore function, regulate chemicals, and support memory. The brain uses nightly sleep cycles to clean up and reorganize itself.
Why do small rewards make us want to repeat an action?
Rewards trigger dopamine-based learning circuits that help the brain predict what is worth repeating. Even a small payoff can reinforce behavior if it arrives at the right time.
Why do music and rhythm feel so powerful to the brain?
Music engages auditory, motor, emotional, and reward circuits at the same time. That multi-system activation helps explain why rhythm can move us emotionally and make us want to tap along.
What is the gut-brain axis?
The gut-brain axis is the two-way communication network between the digestive system and the brain. It involves nerves, hormones, immune signals, and gut microbes.
What are neurotransmitters?
Neurotransmitters are chemical messengers that nerve cells use to communicate. They carry signals across synapses.
What is a split-brain?
A split-brain refers to the condition after the corpus callosum is severed, usually to reduce severe epilepsy. It can reveal how the two hemispheres process information differently.
What is hemispheric lateralization?
Hemispheric lateralization is the tendency for certain brain functions to be more specialized in one hemisphere than the other. Language, spatial processing, and some emotional tasks can show this pattern.
What is the mirror neuron system?
The mirror neuron system refers to brain cells that activate both when a person performs an action and when they observe someone else performing it. It is thought to be involved in action understanding and imitation.
When was the split-brain research of Roger Sperry and Michael Gazzaniga first published?
Their influential split-brain work was published in the early 1960s, with major papers appearing in 1962.
When was the first EEG recorded from a human brain?
The first human electroencephalogram was recorded in 1924 by Hans Berger.
When was the first description of neuroplasticity widely accepted?
The modern scientific idea of neuroplasticity became widely accepted in the late 20th century, especially from the 1960s onward.
Where is the hypothalamus located?
The hypothalamus is located below the thalamus, at the base of the brain. It forms part of the diencephalon.
Which human organ contains the most neurons?
The brain contains the most neurons in the human body. It is estimated to have about 86 billion neurons.
Which human cell type has the longest known lifespan?
Many neurons can last for an entire human lifetime. Some brain cells are formed before birth and persist for decades.
Which brain network is most active when the mind is at rest and wandering?
The default mode network is most active during rest and mind-wandering. It includes regions such as the medial prefrontal cortex and posterior cingulate cortex.
Which brain chemical is most closely linked to the brain’s reward and motivation system?
Dopamine is the best-known neurotransmitter for reward, motivation, and learning. It is strongly involved in reinforcement and movement as well.
Whose discovery explained the function of the cerebellum?
Marie-Jean-Pierre Flourens showed that the cerebellum helps coordinate movement. His 19th-century experiments were among the first to link a brain region to a specific function.
How do neurons communicate with each other?
Neurons pass signals using electrical impulses and chemical messengers called neurotransmitters. At a synapse, one neuron releases neurotransmitters that bind to receptors on the next cell.
Why are some people more likely to be left-handed?
Left-handedness is influenced by a mix of genetics, brain development, and prenatal factors. It is not controlled by a single gene, and about 10% of people are left-handed.
When was the first electroencephalogram (EEG) recorded in humans?
The first human EEG was recorded in 1924 by German psychiatrist Hans Berger. He later published his findings in 1929.
When was the first brain imaging scan of a living person done with a CT scanner?
The first CT scan of a living human brain was performed in 1971. CT was introduced clinically in the early 1970s.
When was the first MRI scan of a human brain performed?
The first MRI scan of a human brain was made in 1977. MRI became a major medical imaging tool in the 1980s.
When was the first demonstration of mirror neurons reported?
Mirror neurons were first reported in 1992 by researchers in Italy. They were discovered in macaque monkeys.
When was the first map of the motor cortex published?
The motor cortex was mapped in the early 20th century, with major work by Wilder Penfield in the 1930s and 1940s. His famous homunculus map came later in the 20th century.
Which bird has the strongest recorded song memory?
Songbirds such as the zebra finch are known for excellent vocal learning, and some can remember and reproduce complex songs for long periods.
Whose name is associated with the tiny folds in the cerebellum’s surface?
The cerebellar folia are not named after a person, but they are the thin, leaf-like folds on the cerebellum. These folds increase surface area for motor control.
Whose name is attached to the brain’s reward-prediction learning in dopamine research?
Wolfram Schultz’s. His studies helped show that dopamine neurons respond to reward prediction errors.
Whose work first described the ‘split-brain’ findings from patients with severed corpus callosum?
Roger Sperry’s. His split-brain research in the 1960s showed how the two hemispheres can process information differently.
Whose discovery first showed that the brain can change with experience, not just in childhood?
Michael Merzenich’s. His research was key in showing adult neuroplasticity.
Whose name is attached to the phantom-limb theory that missing limbs can still be ‘felt’?
Silas Weir Mitchell’s. He described phantom limb sensations in wounded soldiers during the American Civil War era.
Whose theory of the ‘triune brain’ tried to explain the human brain as three evolutionary layers?
Paul MacLean’s. He proposed the triune brain model in the mid-20th century.
Whose name is attached to the brain wave pattern first linked to relaxed wakefulness?
Hans Berger’s. He discovered the electroencephalogram, or EEG, in the 1920s.
Whose name is used for the protective layer around nerve fibers that speeds up signals in mammals?
The Schwann cell is named for Theodor Schwann. These cells form myelin in the peripheral nervous system, helping nerves transmit signals quickly.
Whose work first showed that a mammal could regenerate damaged brain tissue better than expected?
J. Z. Young’s. His studies of octopuses were famous, but mammalian brain regeneration research was advanced later by scientists such as Sally Temple; no single pioneer is universally credited.
Whose discovery first showed that the mammalian brain is organized into lobes with specialized functions?
Paul Broca and later neuroanatomists helped establish localized brain function in mammals in the 19th century.
How fast does a nerve impulse travel?
Nerve impulses can travel from a few meters per second in unmyelinated fibers to over 100 meters per second in heavily myelinated ones. Speed depends on fiber size and myelin.
How does dopamine shape motivation and reward?
Dopamine helps the brain learn what predicts reward and encourages repetition of useful actions. It is more about motivation and learning than simple pleasure.