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Jon Hamilton

Researchers are prescribing exercise as if it were a drug in a study that aims to see if it can prevent Alzheimer's disease.

"We are testing if exercise is medicine for people with a mild memory problem," says Laura Baker, principal investigator of the nationwide EXERT study and associate director of the Alzheimer's Disease Research Center at Wake Forest School of Medicine.

In a waiting room at the Banner Alzheimer's Institute in Phoenix, a 74-year-old woman named Rubie is about to find out whether she has a gene that puts her at risk for Alzheimer's.

"I'm a little bit apprehensive about it, and I hope I don't have it," she says. "But if I do, I want to be able to plan for my future."

The gene is called APOE E4, and it's the most powerful known genetic risk factor for Alzheimer's after age 65.

Alzheimer's disease begins altering the brain long before it affects memory and thinking.

So scientists are developing a range of tests to detect these changes in the brain, which include an increase in toxic proteins, inflammation and damage to the connections between brain cells.

What sounds like music to us may just be noise to a macaque monkey.

That's because a monkey's brain appears to lack critical circuits that are highly sensitive to a sound's pitch, a team reported Monday in the journal Nature Neuroscience.

The finding suggests that humans may have developed brain areas that are sensitive to pitch and tone in order to process the sounds associated with speech and music.

Scientists are setting a new course in their quest to treat Alzheimer's disease.

The shift comes out of necessity. A series of expensive failures with experimental drugs aimed at a toxic protein called amyloid-beta have led to a change in approach.

Scientists have found a way to transform brain signals into spoken words and sentences.

The approach could someday help people who have lost the ability to speak or gesture, a team from the University of California, San Francisco reported Wednesday in the journal Nature.

When you're thirsty, a swig of fresh water brings instant relief. But gulp down some salty sea water and you'll still feel parched.

That's because your brain is trying to keep the concentration of salt in your body within a very narrow range, says Zachary Knight, an associate professor in physiology at the University of California, San Francisco and an investigator with the Howard Hughes Medical Institute.

The claim was extraordinary.

More than 20 U.S. diplomats in Cuba had "suffered significant injuries" in a series of attacks that seemed to target the brain. Or at least that's what State Department officials told reporters during a briefing in September 2017.

A couple of weeks later, President Trump went even further. "I do believe Cuba is responsible," he said during a Rose Garden news conference.

Editor's note, March 6, 9:30 a.m.: This story was updated to include information about the price of Spravato.

The Food and Drug Administration approved the first drug that can relieve depression in hours instead of weeks.

Esketamine, a chemical cousin of the anesthetic and party drug ketamine, represents the first truly new kind of depression drug since Prozac hit the market in 1988.

Primary care doctors are really good at checking seniors' cholesterol levels and blood pressure but often fail to use tests that could detect dementia.

Fewer than half of primary care doctors surveyed say they routinely test patients 65 and older for problems with memory and thinking, according to a report released Tuesday by the Alzheimer's Association.

Women tend to have more youthful brains than their male counterparts — at least when it comes to metabolism.

While age reduces the metabolism of all brains, women retain a higher rate throughout the lifespan, researchers reported Monday in the journal Proceedings of the National Academy of Sciences.

For comedian Lewis Black, anger is a job.

Black is famous for his rants about stuff he finds annoying or unfair or just plain infuriating.

Onstage, he often looks ready for a fight. He leans forward. He shouts. He stabs the air with an index finger, or a middle finger.

To a scientist, Black looks a lot like a belligerent dog, or an irritated gerbil.

On January 28, 1969, an oil well off the coast of Santa Barbara, Calif., experienced a blowout. The result was an oil spill that at the time ranked as the largest in U.S. waters.

The disaster, which made headlines across the nation, helped create the modern environmental movement. It also led to restrictions on offshore drilling — restrictions the Trump Administration is trying to loosen.

The events that led to the spill began one morning on Platform A, a rig located about six miles from the coast and operated at the time by Union Oil.

Scientists have found a biological clue that could help explain why African-Americans appear to be more vulnerable than white Americans to Alzheimer's disease.

A study of 1,255 people, both black and white, found that cerebrospinal fluid from African-Americans tended to contain lower levels of a substance associated with Alzheimer's, researchers report Monday in the journal JAMA Neurology.

Yet these low levels did not seem to protect black participants from the disease.

Just in time for the winter solstice, scientists may have figured out how short days can lead to dark moods.

Two recent studies suggest the culprit is a brain circuit that connects special light-sensing cells in the retina with brain areas that affect whether you are happy or sad.

When these cells detect shorter days, they appear to use this pathway to send signals to the brain that can make a person feel glum or even depressed.

There's new evidence that mild pulses of electricity can relieve depression — if they reach the right target in the brain.

A study of 25 people with epilepsy found that those who had symptoms of depression felt better almost immediately when doctors electrically stimulated an area of the brain just above the eyes, a team reported Thursday in the journal Current Biology.

Scientists may have caught a glimpse of what sadness looks like in the brain.

A study of 21 people found that for most, feeling down was associated with greater communication between brain areas involved in emotion and memory, a team from the University of California, San Francisco reported Thursday in the journal Cell.

A substance that gives pot its kick appears to reduce the brain changes associated with Alzheimer's disease – at least in mice.

In mice that had been genetically tweaked to develop symptoms like those of Alzheimer's, animals that received a synthetic form of tetrahydrocannabinol for six weeks performed as well as healthy mice on a memory test, scientists reported Tuesday at the Society for Neuroscience meeting in San Diego.

You hear a new colleague's name. You get directions to the airport. You glance at a phone number you're about to call.

These are the times you need working memory, the brain's system for temporarily holding important information.

"Working memory is the sketchpad of your mind; it's the contents of your conscious thoughts," says Earl Miller, a professor of neuroscience at MIT's Picower Institute for Learning and Memory.

An ancient part of the brain long ignored by the scientific world appears to play a critical role in everything from language and emotions to daily planning.

It's the cerebellum, which is found in fish and lizards as well as people.

But in the human brain, this structure is wired to areas involved in higher-order thinking, a team led by researchers from Washington University in St. Louis reports Thursday in the journal Neuron.

Microsoft co-founder Paul Allen, who died Monday, made his fortune from software that ran computer brains.

But Allen's own passion was for the human brain.

"The human brain works in, so far, mysterious and wondrous ways that are completely different than the ways that computers calculate," he told NPR during an interview in 2003. "Things like appetite or emotion, how do those function in the brain?"

In order to see the red of a sunset or the green of spring leaves, developing human eyes need to get the right hormone at the right time.

That's the finding of a team of scientists who studied how color vision develops using hundreds of human retinas grown in the lab.

Experiments with two gambling monkeys have revealed a small area in the brain that plays a big role in risky decisions.

When researchers inactivated this region in the prefrontal cortex, the rhesus monkeys became less inclined to choose a long shot over a sure thing, the team reported Thursday in the journal Current Biology.

Government scientists have presented new evidence that the plastic additive BPA isn't a health threat.

Low doses of the chemical given to hundreds of rats, "did not elicit clear, biologically plausible adverse effects," said K. Barry Delclos, a research pharmacologist at the Food and Drug Administration's National Center for Toxicological Research.

Kids with ADHD are easily distracted. Barn owls are not.

So a team at Johns Hopkins University in Baltimore is studying these highly focused predatory birds in an effort to understand the brain circuits that control attention.

The team's long-term goal is to figure out what goes wrong in the brains of people with attention problems, including attention deficit hyperactivity disorder.

A new study suggests that ketamine, an increasingly popular treatment for depression, has something in common with drugs like fentanyl and oxycodone.

The small study found evidence that ketamine's effectiveness with depression, demonstrated in many small studies over the past decade, comes from its interaction with the brain's opioid system. A Stanford University team reported their findings Wednesday in The American Journal of Psychiatry.

Scientists have taken another step toward understanding what makes the human brain unique.

An international team has identified a kind of brain cell that exists in people but not mice, the team reported Monday in the journal Nature Neuroscience.

Chris Ferrari was just 18 the first time he balanced a rocket launcher on his right shoulder and aimed it at a practice target.

"Your adrenaline's going and you're trying to focus on getting that round to hit, and then you go to squeeze that trigger and, you know."

Boom!

The report is loud enough to burst the eardrums of anyone not wearing military-grade hearing protection. And the blast wave from the weapon is so powerful it feels like a whole-body punch.

There's new evidence that a woman's levels of female sex hormones, including estrogen and progesterone, can influence her risk of Alzheimer's and other forms of dementia.

Women are less likely to develop dementia later in life if they begin to menstruate earlier, go through menopause later, and have more than one child, researchers reported Monday at the Alzheimer's Association International Conference in Chicago.

Two common herpes viruses appear to play a role in Alzheimer's disease.

The viruses, best known for causing a distinctive skin rash in young children, are abundant in brain tissue from people with Alzheimer's, a team of scientists reports Thursday in Neuron. The team also found evidence that the viruses can interact with brain cells in ways that could accelerate the disease.

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