Anesthetics slow brain activity by promoting inhibitory neurotransmitters

Opioids mimic naturally produced endorphins to dull pain

Once in the body, opioids bind to naturally occurring opioid receptors typically used by endorphins to temper pain. They trigger the release of dopamine, a desire-related hormone, and decrease noradrenaline, a neurotransmitter involved in heart and breathing rate regulation, meaning high doses can slow these processes to dangerous levels.

How four types of psychedelics affect the brain

Brain imaging shows that ayahuasca, MDMA, DMT, and psilocybin profoundly affect neural activity, giving rise to higher states of introspection and consciousness. This article details exactly how each of these drugs physically affects the brain and what that means for mental health treatment. Some of these drugs quiet the brain or trigger the release of neurochemicals associated with mood regulation and learning.

How depression affects the brain

Treatment for depression has historically hinged on the theory that the condition was caused by underactive or abnormal neurotransmitters, specifically serotonin and norepinephrine. This four-minute video by Yale Medicine details how these neurotransmitters didn't explain the symptoms of depression but, two other neurotransmitters involved in regulating mood and emotion did. GABA and glutamate, some of the brain's most plentiful neurotransmitters, may possibly be the source of depressive symptoms.

How alcohol rewires your brain

Alcohol doesn't just make you tipsy—it rewires your brain chemistry in real time. It slows your brain with GABA, spikes dopamine to make you feel unstoppable, and blocks glutamate so you can't form memories. That mix explains everything from slurred speech to blackouts … and brutal hangovers.

Surgery before the dawn of anesthesia

The arc toward anesthetics was painfully slow, with early pain mitigation offerings ranging from analgesics—drugs that dim pain but don't block it—and numbing surgical sites with cold water to gassing patients with carbon dioxide or bashing or bleeding them unconscious. Such treatments and the torturous surgery they preceded led many to avoid even life-saving procedures, and those who survived often kept silent about the trauma.

Certain medications that affect blood flow or mood boost the risk of heatstroke

Drugs that narrow blood vessels, beta blockers that regulate blood pressure, diuretics, antidepressants, and antipsychotics can all affect the body's ability to regulate its internal body temperature, and so individuals taking these medications need to take special care in extreme heat and when exercising in hot conditions.

Scientists are studying dying patients' brain activity in the final moments of life

In the final moments of life there are distinctive bursts of coordinated neural activity. Researchers are interested in parsing that data to better understand the dying process and also exploring how this data relates to our understanding of consciousness.

Exercise releases chemicals that enhance cognitive function

Neurotransmitters like dopamine, serotonin, and norepinephrine, along with increased brain-derived neurotrophic factor levels, enhance a wide range of brain functions. New research demonstrates a direct link between movement and numerous cognitive benefits, including memory, learning, and stress resilience.

Sleep disorders can exacerbate neurological and other health conditions

Brain regions that control sleep sit adjacent to those that regulate the autonomic nervous system, which controls involuntary bodily functions like heart and breathing rates. These neighbors influence each other, meaning poor sleep can impair or negatively impact the ANS, further disturbing sleep.

Deep brain stimulation helps manage movement in patients with neurological disorders

DBS is a surgical procedure that uses implanted electrodes to send electrical signals to targeted areas in the brain, interrupting abnormal neural activity. It may be implemented when medications lose effectiveness or cause disruptive side effects.

Delta brain waves happen during deep sleep, while REM cycles resemble being awake

As the brain cycles from wakeful rest to deep sleep, different brain waves emerge. Alpha waves occur during restful waking states, while theta waves can be associated with light sleep and meditation. Delta waves are observed during deep sleep—but REM cycles more closely resemble active awake states.

Gamma Knife surgery uses incredibly precise, high-energy light to treat patients

A form of brain stereotactic radiosurgery, this non-invasive technology concentrates beams of light onto specific tumors to damage the DNA of malignant cells, killing them. The gamma rays used are in the same part of the electromagnetic spectrum as those produced in nuclear reactions, cosmic ray collisions, and radioactive decay.

Odor blockers use nonpolar oils to trap smelly polar molecules

In the case of feces, gut bacteria produce compounds such as skatole and hydrogen sulfide, which the brain registers as unpleasant. Because oils do not dissolve in water, they can be used to create a layer on the surface that prevents smelly compounds underwater from escaping into the air.

Predictive brain implants raise ethical concerns about patient autonomy after surgery

These devices can accurately forecast neurological events like seizures and suggest or even automatically deliver responses. Their constant monitoring and prescriptive functions may blur the line between patient choice and device influence.

US FDA recently approved the first new schizophrenia drug in decades

Though other antipsychotics block dopamine receptors, a new drug, Cobenfy, influences dopamine levels via a different pathway—it stimulates a pair of specialized receptors in the brain that control the release of a substance called acetylcholine. This alternative approach may help patients avoid serious side effects like weight gain. (Some users may experience a paywall.)

GLP-1s may lower inflammation, possibly helping to combat cognitive decline

An analysis of existing GLP-1 research, published in April 2025, indicated that GLP-1 drugs reduce inflammation, with numerous health benefits. The work notes that GLP-1s were linked with a statistically significant reduction in dementia in randomized clinical trials.

Why 'spacing out' or dissociating may help reduce trauma awareness

Dissociation may have developed as a defense mechanism in the brain to help navigate intense emotional or physical situations by providing out-of-body experiences that put distance between the mind and the environment. However, in about 1.1% and 1.5% percent of the general population, a severe form of this separation can produce alternate identities, or alters.

Are you hypnotizable?

What causes some people to genuinely fall under the spell of hypnosis and others not? The technique only appears to work easily on about 10% of people, and a variety of both genetic and psychological factors determines one's susceptibility. Researchers suggest effective hypnosis has more to do with a person's self-control than with external influence—and the technique can have tangible benefits.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Sleep deprivation leads to buildup of danger molecules in the gut

Fruit flies genetically engineered to be awake for as long as they live tend to live half as long as their well-rested brethren. Analysis shows these modified flies suffer from a buildup of DNA-destroying reactive oxygen species in their guts. When enabled to sleep, the flies live as long as their counterparts.

Inhalers dilate airways and reduce inflammation

People with asthma suffer from constricted airways in their lungs, whether from muscle pressure, mucus buildup, or inflammation. Inhalers help people breathe medicine directly into their lungs to immediately relieve these symptoms.

The human brain only uses 5% more energy during active tasks versus resting

Despite only being 2% of the weight of a human body, the average adult brain consumes 20% of its energy, with the majority of it spent on maintaining homeostasis—the stable equilibrium conditions of temperature, acidity, blood sugar, and other properties in the body. For infants, the consumption is closer to 50%.

Drugs in space: the pharmacy orbiting the Earth

Researchers are developing pharmaceutical solutions for astronauts, whose bodies may not respond the same way in space as they would on Earth. Similar to how microgravity causes changes to astronaut physiology, the environmental shift enables new...

How specialized oxygen mixtures like heliox enable deep diving without feeling drunk

Beyond a depth of about 30 meters (98 feet), if divers are breathing surface air, which is about 78% nitrogen, underwater pressure forces more nitrogen into the bloodstream and induces nitrogen narcosis, whose symptoms resemble alcohol intoxication. Through saturation diving, where nitrogen is replaced with helium—an inert gas—deep divers can maintain cognitive function while working for extended periods.

Neurons send signals through electrical impulses and chemical messengers

By converting electrical signals into chemical messages at synapses, neurons allow information to travel throughout the nervous system. With repeated use, synapses grow stronger, enhancing the associations between neurons.

Coffee gives you energy, but it ultimately makes you more tired

The caffeine in coffee delays your brain's fatigue signals. Caffeine blocks adenosine, a compound that builds up as you burn energy and signals rest. Once caffeine wears off, adenosine floods back, leaving you even more tired.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

'Silent' fireworks have gained more interest in recent years as a quieter celebratory option.

Explore what it's like inside a patient isolation unit, used in situations such as treating a patient or suspected patient with Ebola.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

'Shogun,' a 1980s TV series, helped popularize sushi in the US by stimulating an American interest in Japanese culture.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

The Ramones' 'Pet Sematary,' the theme song for the Stephen King novel of the same name, was written while the band was admiring the writer's collection of horror memorabilia.