Hippocampus

Two brain areas team up to make mental maps

map London
map London

We don’t always use a map or app to get around. Often, we rely on our brains to navigate. A new study shows which parts of the brain will participate in this.

Following a map isn’t the only time people test their skills at navigation. We find routes all the time, whether it’s from one end of the house to another or to school and back. How does your brain get you to your destination? Two brain areas work together, a new study finds. One taps your memory to figure out where you are. Another uses that information to plan the path ahead. This discovery could help scientists one day design spaces for people who have difficulty finding their way.

The word “memory” makes people think of the past. But without it, no one could plan for the future. This is especially true in navigation, says Amir-Homayoun Javadi. He’s a neuroscientist — someone who studies the brain — at the University of Kent in Canterbury, England. He and his colleagues wanted to figure out how the brain finds different routes to a destination.

The scientists recruited 24 volunteers for a two-hour tour of Soho. It’s a neighborhood in London, England. Guides led the participants around, pointing out landmarks, book shops, cafes and other points of interest. These might help the volunteers later find their way. As they pointed things out, the guides also told the participants which direction they were facing — north, south, east or west.

One day later, the volunteers came to the lab and lay down inside a machine that does functional magnetic resonance imaging, or fMRI. This brain scanner tracks the flow of blood in the brain. That blood carries oxygen. If a part of the brain is very active, it will need more oxygen. So more blood will move toward it. Scientists therefore use blood flow as a way to pinpoint which brain areas are working hard during a task.

As the participants lay in the machine, they saw 10 videos of the neighborhood they toured the day before. In five of them, they “traveled” without having to find their own way. For the rest, they had to use a computer to navigate…

Brain gains seen in elderly mice injected with human umbilical cord plasma

mouse hippocampus
YOUTHFUL GLOW In the hippocampus of a 1-month-old mouse, some nerve cells (red) produce the protein TIMP2 (green), which declines with age and may help keep the brain young. Blue indicates microglial cells.

Plasma taken from human umbilical cords can rejuvenate old mice’s brains and improve their memories, a new study suggests. The results, published online April 19 in Nature, may ultimately help scientists develop ways to stave off aging.

Earlier studies have turned up youthful effects of young mice’s blood on old mice (SN: 12/27/14, p. 21). Human plasma, the new results suggest, confers similar benefits, says study coauthor Joseph Castellano, a neuroscientist at Stanford University. The study also identifies a protein that’s particularly important for the youthful effects, a detail that “adds a nice piece to the puzzle,” Castellano says.

Identifying the exact components responsible for rejuvenating effects is important, says geroscientist Matt Kaeberlein of the University of Washington in Seattle. That knowledge will bring scientists closer to understanding how old tissues can be rejuvenated. And having the precise compounds in hand means that scientists might have an easier time translating therapies to people.

Kaeberlein cautions that the benefits were in mice, not people. Still, he says, “there is good reason to be optimistic that some of these approaches will have similar effects on health span in people.”

Like people, as mice age, brain performance begins to slip. Compared with younger generations, elderly mice perform worse on some tests of learning and memory, taking longer to remember the location of an escape route out of a maze, for instance. Researchers suspect that these deficits come from age-related trouble in the hippocampus, a brain structure important for learning and memory.

Every fourth day for two weeks, Castellano and colleagues injected old mice with human…

Study links ADHD to five brain areas

classroom kids
classroom kids

Some kids have a hard time concentrating in class or turning in homework on time. Or they might talk at times when teachers have asked for quiet. Such behaviors may point to attention deficit hyperactivity disorder, or ADHD. At least 7 in every 100 children may have this condition. Medicines and behavioral therapy — a type of talk therapy — can help treat the symptoms of this disorder. But scientists wanted to know what was behind it. Now, using brain imaging, they have just turned up five areas of the brain linked with symptoms of ADHD. At least two of those regions are smaller in kids with ADHD than in those without the disorder.

More than 80 researchers co-authored the new study. Martine Hoogman at Radboud University Medical Center in Nijmegen, the Netherlands, led this massive research team. Her group studied 1,713 people with ADHD and 1,529 others without it. That makes it the largest ADHD study to date. Its participants ranged in age from 4 to 63. They live in 23 places around the world.

The researchers scanned participants’ brains to probe what was going on inside their heads. They used magnetic resonance imaging (MRI). It relies on magnetic fields and radio waves to picture tissues deep inside the body.

By comparing brain scans of people with and without ADHD, the researchers showed that the volumes of five brain areas were smaller in kids with ADHD. The size of the entire brain also was…