Your brain appears to age in five distinct stages, with the pattern of connections inside your brain shifting, on average, around ages 9, 32, 66, and 83. (Paywall may apply.)

How aging degrades neural functioning in the brain over time

Aging affects the brain perhaps more than any other organ in the body. Throughout life, the brain experiences radical shifts in the number of neurons, synaptic connections between neurons, and hormone levels that regulate our mood and processing.

Your brain moves through four distinct sleep stages every night

Each stage plays a key role in memory, repair, restoration, and other key biological functions. The full cycle generally proceeds from light sleep and deep rest into vivid REM dreaming, which repeats between three and five times nightly.

A pregnant woman's brain sheds gray matter, perhaps explaining 'baby brain'

The brain areas involved in processing information and emotions decrease by an average of almost 5% during pregnancy. Researchers discovered in a 2025 study that this mostly temporary change—the brain hadn't fully returned to its normal size six months after pregnancy—seems to be associated with self-reported improved bonding and less hostility toward the child postpartum.

The evolution of the human brain

The human brain, in all its staggering complexity, is the product of millions of years of evolution. Read on to find out about brain size and intelligence, language and brain development, and more.

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.

Strength training appears to make for a healthier, youthful-looking brain

A study from 2025 links having higher amounts of muscle with a more youthful-looking brain age. Scientists analyzed data from more than 1,100 healthy adults around their mid-50s after they underwent full-body MRIs, comparing muscle, fat, and brain age appearances from the scans.Their findings link strength training and controlling visceral fat with improved brain health. The research didn't tease apart why this benefit occurs.

Like fingerprints, brain anatomy is unique too

Researchers have discovered that a combination of experiences and genetic factors shape the anatomy of the human brain. They found even quick experiences affect the brain’s genetic makeup, which—over time—means every person develops a completely unique brain anatomy. While brain imaging could be used to identify individuals, it remains much more expensive than fingerprinting for now. Read to found out more about this study from the University of Zurich.

Aging is a complex biological process affecting our cells, tissues, and organs.

Chronological versus biological age

Science has come to understand different types of aging. What we call age is simply the number of years since birth, or chronological age. At the cellular level, biological aging happens at different rates for different people, and explains why some seem to age more quickly (or slowly).

Five to ten percent of Alzheimer's cases are early-onset

Early-onset Alzheimer’s typically emerges around 40 to 50 years of age, with devastating effects. This video follows Brian, diagnosed with the disease at age 54, as he travels the country as an advocate for research and discusses the progressive mental fog of Alzheimer’s.

Super-agers: seniors 80 and above with the memory ability of people in their 50s

Studies show the number one indicator of whether someone is a "super-ager" is not diet or genetics, but the extent of their social relationships. Moreover, scans reveal noticeable physical differences in certain parts of the brain in patients with extensive social networks.

Each part of the human body experiences aging differently

With global average life expectancy cresting at 73 years, understanding how the body ages is imperative to effective medical treatment and maintaining a desired quality of life. This 13-minute video dives into how the body and its organs age "from head to toe."

What’s with the teen brain, anyway

In this video NIDA explores the intriguing similarities between the processes of brain development and computer programming. This analogy helps us understand why toxic environmental factors like drugs, bullying, or lack of sleep strongly affect a teenager’s life The information provided by this video can empower your children or students with information they need make better decisions.

Explore an interactive 3D model of the brain

The brain contains about 86 billion neurons—nervous system cells—and controls vital bodily functions via electrochemical signals. Neurons form circuits through axons, and different brain regions use these circuits to perform specific tasks.

MS can damage the brain up to 7 years before symptoms appear

Recent research scouring blood samples from 134 people with MS, both before and after their diagnosis, found that about seven years before these patients were diagnosed, there was a spike in a protein called myelin oligodendrocyte glycoprotein—indicating disease-associated damage to the protective myelin around nerve fibers.

Why do humans have such long childhoods?

Humans have over twice as long childhoods than other animals with similar lifespans like whales and elephants. A human child can grow for nearly 20 years before they become a reproducing adult. Researchers believe there's a connection between long childhoods and human's unusually large brain size, though the science is not totally clear. Dive into what scientists know here.

An interesting perspective on whether (and how) brain size matters in cognitive ability

Some brains are bigger than others, but what is the relevance, if any, to brain size and intelligence? This Scientific American article explores the question and offers examples. It also visually compares frontal slices of several mammals' brains, showing that humans don't necessarily have the biggest cerebrums on the block.

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.

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%.

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.

Schizophrenia symptoms, like psychosis, often first emerge among young adults

A combination of genetics, significant brain changes to the frontal cortex, and hormonal changes during young adulthood—late teens to early 30s—result in schizophrenic symptoms often showing up during this period. The stress of life changes at that age may also be a contributing factor.

The dreaming brain, as understood by scientists

Technology has advanced to where the seemingly separate fields of psychology and neuroscience are asking the same questions about dreams, such as whether they're more closely related to perception or visualization. Some field-intersecting findings include research that shows people with impaired face perception don't dream of faces, those with brain legion-related cognition difficulties deal with similar issues in dreams, and children's dreams change in parallel to their cognitive development.

Grief rewires the human brain

The human brain handles stress and emotional traumas similarly. In response to the emotional stress of a situation like the death of a loved one, divorce, or abuse, the brain may strengthen or weaken connections between nerves to form new neural connections. Over time, chronic stress can diminish brainpower, reducing overall nerve growth and memory to shift resources to enable elevated fear responses and enable humans to survive.

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.

Brain training game creates long-lasting changes in the brain that may help protect against dementia

Findings published in 2026 that tracked more than 2,000 older adults, examining dementia onset and completion of cognitive speed training activities, provide some of the strongest evidence yet that cognitive training games can help protect against dementia. Participants who underwent speed training and received booster sessions had a 25% reduction in the risk of dementia diagnosis compared with the control group.

What is the brain up to when the mind wanders?

As you stare into the distance while washing your home's seemingly never-ending pile of dishes, the brain activates its default mode network. This collection of "task-negative" brain regions associated with memory, reward, action consideration, and prediction alight with activity when humans mentally turn inward, possibly giving rise to the brain's ability to wander and humans' ability to construct internal narratives about the world.

How can octopuses and MDMA help scientists understand the human brain?

Research shows that psychedelics may induce something called "critical periods" in the adult brain, which can make our brains more open to learning and changing, like they once were back in early childhood. Psychedelics similarly change how social creatures like octopuses behave, which demonstrates that these animals could help us better understand our own neurobiology.

Some dementia cases may be linked to microorganisms in the brain

Researchers now know that, much like the gut, the brain is home to an ecosystem of microorganisms—the brain microbiome. While this area of study is still new, some scientists believe 50% of bacteria-caused dementia cases could be treated. (Some users may encounter a paywall.)

How the brain processes a calendar year

When most of us picture a calendar year, we have a foggy image in our minds of the months, in rough, calendar-like grids. But for some folks, that picture is a whole lot more clear. Around 1 percent of the population has a strange ability known as "calendar synaesthesia," which means they're able to visualize in crisp detail an elaborate calendar of the months of the year. Learn how it works here.

Genetic blood test offers an estimated clock on when Alzheimer's symptoms may appear

The 2026 research finding from researchers at Washington University School of Medicine in St. Louis—if validated in broader populations—suggests that an already available blood test could estimate when Alzheimer's symptoms may begin within a margin of several years. The test detects a protein called p-tau217 found in blood plasma and the researchers incorporated the findings from that blood test into a statistical model to come up with the symptom timeline predictions.

'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.

Circadian rhythms shift as we age—making older adults want to go to bed earlier

Throughout our lives our internal biological clocks shift. Early-to-rise toddlers become hard-to-wake teens and eventually early-to-sleep seniors. Circadian rhythm fluctuations throughout our life cycle explain some of these changes.

Visualizing cause of death over time in America

As people age, their life expectancy decreases, but the timing and speed of this decline have evolved over the years. Check out this chart which shows the shift in various causes of death of Americans over the last few decades. Data from the...

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

The "reminiscence bump" causes memories from adolescence to last

Research shows that the "reminiscence bump" phenomenon, which applies to memories formed between the ages of 10 and 30, contributes to songs from those ages triggering the most intense nostalgia. This may be due to biological and hormonal changes enhancing memory effectiveness during adolescence.

Do people really look younger than they used to?

Why do people today look younger than they used to? From style to science, there are 3 surprising reasons we age differently now.

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.

See who Americans spend time with over their lives

Time with friends peaks in the teens and falls sharply by the 30s, while time with coworkers dominates middle age. After retirement, both nearly vanish, and time spent alone climbs steadily to nearly 8 hours a day by age 80.

Cells can last in the human body from days to a person's entire life

Despite claims that a person's body replaces itself every seven to 10 years, the rate at which cells die and are replaced varies by cell type. Gastrointestinal cells that line the digestive tract and stomach last only a few days, while some heart muscle cells and most neurons are around from birth until death.

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.

How frontotemporal dementia changes your personality

Significant changes in personality later in life are often attributed to psychological factors. But Dr. Bruce Miller, long-time researcher of FTD, argues this shift is most often attributable to changes in the brain.

Multiple new research paths may lead to slowing (or even reversing) aging

Aging has always been inevitable, but fasting, epigenetic reprogramming, and parabiosis seem to help people stay young. By studying centenarians, memory, and even the humble roundworm, scientists are looking for the genetic basis to live not just a long life, but a healthy one.

As of 2025, the internet is entering its fourth phase, with three more to go

Since the inception of the internet as a tool for connecting teams of researchers, technological and infrastructure advancements have progressively increased connectivity. Connections between computers, mobile devices, all devices, and now AI agents will be succeeded by an internet that integrates perception and the senses toward an eventual quantum internet.

Menopause affects the brain in complex ways

Lisa Mosconi, a neuroscientist studying the impact of menopause on the brain, explains in this video how menopause directly impacts a woman's brain health and explores why this is an important and often overlooked area in menopause and women's aging healthcare discussions.

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.

8 key milestone ages in retirement

At age 50, you can make catch-up contributions to retirement accounts. At age 65, you become eligible for Medicare.

Why patterns in art are so pleasing

Repeated visual cues like shapes or lines derive from the brain's innate compulsion to identify faces, places, bodies, and more. With repeated shapes, the brain seeks out resolution to the subtle variations between them. See examples in art and music.

Playing music enhances the creation, storage, and retrieval of memories

Scans of the brains of individuals who play instruments have shown enhanced connectivity between multiple brain regions—visual, auditory, and motor cortices—and the corpus callosum, which connects the two brain hemispheres. These complex connections are strengthened through practice and then used in other activities that involve both logic and creativity. The brains of musicians also appear to give experiences multiple types of memory tags, such as audio, emotional, and conceptual, improving their processing.

Schizophrenia is being studied with pea-sized 'mini-brains'

Brain organoid research is enabling researchers to study distinct electrical firing patterns associated with schizophrenia. These "mini-brains" that are constructed in the lab from patients' cells could lead to better diagnosis approaches and drug development.

The average retirement age by country, visualized

In the US, the average retirement age was 64 as of 2020. The Organization for Economic Co-operation and Development projects a two-year increase in the average retirement age by the mid-2060s.