A brain scientist's experience with a stroke

Left versus right brain strokes vary significantly in long-term effects

Due to the high complexity of the brain, the aftereffects of a stroke can have widely different manifestations, ranging from minor temporary impairments to rapid death. Whether a stroke results in paralysis, speech impairments, loss of bodily function, or death will depend on whether it occurs in the left or right hemispheres or the brain stem.

Someone suffers from a stroke every 40 seconds

Every 40 seconds, someone in the US experiences a stroke—and every minute without treatment destroys millions of brain cells. This explainer breaks down the two main types of strokes, their risk factors, and how early detection could change outcomes in the future.

Medical recognition of strokes stretches back to ancient Greece

Every minute, 750 milliliters of blood flows to the brain, supplying 20% of the body’s oxygen. A sudden disruption—whether from a clot (ischemic stroke) or a bleed (hemorrhagic stroke)—can be life-threatening. From ancient Greek theories to modern CT and MRI scans, here’s how stroke science has evolved over time.

Using AI to restore speech 30 years after a stroke

Through a novel surgical procedure involving electrodes implanted in the brain, along with the help of artificial intelligence, a stroke patient is regaining her ability to speak. This technology converts her thoughts into speech through a digital avatar, allowing her to verbally express herself for the first time in decades.

Take a quiz to discover your brain care score

Each year, nearly 800,000 Americans have a stroke. With such a high occurrence rate, you may be asking yourself what you could do now to prevent a future stroke. Researchers at Harvard collaborated to answer this question by coming up with a "Brain Care" scoring system. Take the quiz to learn the quality of your brain health today and pick up helpful insights to lower your risk of stroke and dementia well into the future.

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.

How a brain injury created a mathematical mind

In 2002, two men savagely attacked Jason Padgett outside a karaoke bar, leaving him with a severe concussion--and turning Padgett into a mathematical genius.

'Susan's Brain': what happens to the brain during addiction

This engaging animation from Harvard Online breaks down the neuroscience of addiction through the story of “Susan’s brain,” demonstrating how addictive substances hijack normal reward pathways. Through clear visual metaphors and approachable narration, it explains complex brain chemistry in understandable terms.

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

Visualize the difference between a healthy brain and one with Alzheimer's

The brain has three main parts—the cerebrum, brain stem, and cerebellum—each combining to control the entirety of the body's operations. Alzheimer's progressively deteriorates the circuitry in these structures, resulting in what we see as the symptoms of the disease.

Losing a brain-computer interface can trigger lasting psychological distress

A clinical trial participant with severe epilepsy described becoming “one” with her implant after it gave her unprecedented control over her seizures. When the device was removed due to the company shutting down, she experienced deep emotional trauma and a sense of personal loss.

How burnout alters your brain

Stress is a normal part of everyday life, and it’s not necessarily all bad. But chronic stress—the kind that leads to burnout—can change the size and functioning of parts of your brain. It can alter the ability to make new brain cells and memories and even potentially modify your DNA.

How science explains déjà vu

Take a fun look at the science explaining the odd experience of déjà vu, which some theories suggest is actually a sign of a healthy brain.

An avowed rationalist discusses his near-death experience

Documentarian Sebastian Junger, a veteran reporter and skeptic discusses his experiences—in particular, a frightening vision—after an aneurysm and internal hemorrhaging left him nearly dead. Junger talks about his NDE, the possible scientific explanations, and how that day changed his fundamental worldview.

How do brain scans work?

There’s only one thing in our solar system sophisticated enough to study itself: the human brain. But this self-investigation is challenging because a living brain is shielded by skull, swaddled in tissue, and made up of billions of tiny cells. How do we study living brains without harming their owners? Two experts explain how the various techniques like EEGs, fMRIs, and PETs work in this TedEd talk.

Physiological changes to the brain on LSD can be captured via MRI

Psychedelics like LSD often take users on novel experiences that can result in lasting shifts in perspective and behavior. See how LSD affects brain activity in this video that details how scientists visually captured the psychedelic's effect for the first time.

Sharp wave ripples in the brain tag experiences for long-term memory storage

These ripples were known to quickly replay neuronal sequences during sleep for consolidation. While awake, they help the brain prioritize memories to remember, and their disruption can impair memory formation.

How family members disappeared into dementia

This narrative feature describes one family's troubling experience with frontotemporal dementia, or FTD, which emerges in the prime of adult life — as young as 40, in some cases — and degrades the brain's ability to plan, organize, express language, understand social cues, and exercise judgment.

Searching for Albert Einstein's stolen brain

Within moments of Einstein's 1955 death, someone reportedly ferreted away the 76-year-old genius's brain. Decades later, a reporter's editor told them to solve the case. This 64-minute podcast episode follows the work of Steven Levy, the reporter who ultimately tracked down Einstein's brain, which had been sliced and stored in slides, goo, and a cardboard box in a scientist's office.

Patient H.M. revealed that the hippocampus was responsible for memory formation

Henry Molaison became a landmark case in psychology after surgery removed large portions of his hippocampus, leaving him unable to form new memories. Upon his death, Molaison's brain was sliced into 2,401 sections and digitized for research.

How brain cells carry information

At any moment, there is an electrical storm coursing through your body. Discover how chemical reactions create an electric current that drives our responses to everything from hot pans to a mother’s caress.

Traumatic brain injury is a leading cause of brain death—and TBIs are trending up

Traumatic brain injury-related deaths have generally increased between 2000 and 2023, growing from roughly 49,000 to more than 68,000 in 2023. Firearm-related suicide is the most common cause of TBI-related deaths in the US, according to the Centers for Disease Control and Prevention. People also experience TBIs from falls, motor vehicle crashes, or assaults.

What happens to the brain during migraine?

Migraine is a neurological condition that can cause debilitating symptoms across various bodily functions. So, what exactly is happening in the brain during these attacks? This five-minute video briefly overviews the internal machinations behind the painful episodes. An incapacitating headache is a common symptom of migraine, though migraine can occur without any headache.

Surviving the crash: a personal story of burnout

Jennifer Moss founded a tech company, had a baby in the middle of the start-up process, and crashed after months of rising exhaustion and disconnection from a career she once felt passionate about. She shared her story of burnout and the techniques she used to turn her life around and repair her relationships in this piece.

The myth of multitasking's prestige

In this article, renowned neurologist Richard Cytowic seeks to expose multitasking as a fool’s errand. Cytowic explains how the brain, like a computer, switches between tasks rather than handling multiple tasks at once. He shares that attempting to focus on multiple activities at the same time consequentially decreases the brain's ability to ignore distractions, maintain focus, and organize information. Instead, he suggests, try to focus on completing one thing at a time.

'The Theory of Everything' depicts Stephen Hawking through Jane Wilde’s eyes

Stephen Hawking credits Jane Wilde, his first wife, for giving him “something to live for” after his ALS diagnosis. This biographical drama of Hawking’s life, adapted from her memoir, details their relationship and the effects his illness and success in physics had on their marriage.

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

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

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

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

How the most famous Ebola book, The Hot Zone, which sold 3.5 million copies and was translated into 30 languages, got aspects of the disease so wrong.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

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

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

In 1945, Surrealist artist Salvador Dalí and legendary animator Walt Disney began collaborating on a short film that was not completed until 2003, years after both men had died.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.