Primates’ brains make visual maps using triangular grids

Primates’ brains see the world through triangular grids, according to a new study published online Sunday in the journal Nature.

Scientists at Yerkes National Primate Research Center, Emory University, have identified grid cells, neurons that fire in repeating triangular patterns as the eyes explore visual scenes, in the brains of rhesus monkeys.

The finding has implications for understanding how humans form and remember mental maps of the world, as well as how neurodegenerative diseases such as Alzheimer’s erode those abilities. This is the first time grid cells have been detected directly in primates. Grid cells were identified in rats in 2005, and their existence in humans has been indirectly inferred through magnetic resonance imaging.

Grid cells’ electrical activities were recorded by introducing electrodes into monkeys’ entorhinal cortex, a region of the brain in the medial temporal lobe. At the same time, the monkeys viewed a variety of images on a computer screen and explored those images with their eyes. Infrared eye-tracking allowed the scientists to follow which part of the image the monkey’s eyes were focusing on. A single grid cell fires when the eyes focus on multiple discrete locations forming a grid pattern.

"The entorhinal cortex is one of the first brain regions to degenerate in Alzheimer’s disease, so our results may help to explain why disorientation is one of the first behavioral signs of Alzheimer’s," says senior author Elizabeth Buffalo, PhD, associate professor of neurology at Emory University School of Medicine and Yerkes National Primate Research Center. "We think these neurons help provide a context or structure for visual experiences to be stored in memory."

"Our discovery of grid cells in primates is a big step toward understanding how our brains form memories of visual information," says first author Nathan Killian, a graduate student in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. "This is an exciting way of thinking about memory that may lead to novel treatments for neurodegenerative diseases."

(Image credit: Mark Snelson)

Death: A special report on the inevitable

The only certain thing in life is that it will one day end. That knowledge is perhaps the defining feature of the human condition. And, as far as we know, we alone are capable of contemplating the prospect of our demise. In these articles we explore the implications: the shifting definition of death, how knowing that we will die gave birth to civilisation, the grim reality of decomposition and whether it makes sense to fear death. But first, when did we become aware of our own mortality?

Bird-brains solve problems spontaneously

In certain situations animals can spontaneously solve problems without planning their actions, according to research from The University of Auckland’s School of Psychology.

Animals rarely solve problems spontaneously, yet certain bird species are able to rapidly gain access to food hung on the end of a long string, by repeatedly pulling and then stepping on the string. For over 400 years it has been a mystery as to how the birds spontaneously solve the “string pulling” problem.

The University of Auckland research shows that such problem solving is not created by birds first solving the problem in their heads. Rather, problem solving occurs online as the bird makes the food on the end of the string move.

“Crows and parrots have long been known to solve the string pulling problem immediately. What our new research shows is that these performances are due to the birds being able to react in the moment to the effects of their actions, rather than being able to mentally plan out their actions,” says Dr Alex Taylor, lead author on the study.

“Thus string pulling appears to be based on a different type of intelligence than we had thought. Instead of the crows using sophisticated cognitive software to model the world, it appears their neural hardware is sufficiently well connected and/or specialised for them to react to the effect of their actions immediately. This allows them to solve problems that other bird species cannot.”

The work, by Dr Taylor, Brenna Knaebe and Professor Russell Gray, titled “An end to insight? New Caledonian crows can spontaneously solve problems without planning their actions”, has been published in the Proceedings of the Royal Society B: Biological Sciences online.

Ping-pong-playing robot learns to play like a person

A ROBOT that learns to play ping-pong from humans and improves as it competes against them could be the best robotic table-tennis challenger the world has seen.

Katharina Muelling and colleagues at the Technical University of Darmstadt in Germany suspended a robotic arm from the ceiling and equipped it with a camera that watches the playing area. Then Muelling physically guided the arm through different shots to return incoming balls.

The arm was then left to draw on its training to return balls hit by a human opponent. When the ball was in a position it had not seen before, the arm used its library of shots to improvise new ones. After an hour of unassisted practise, the system successfully returned 88 per cent of shots.

Other robots have played table tennis in the past, but none have used human demonstration to learn the game. Ales Ude of the Jožef Stefan Institute in Slovenia says that doing so allows robots to play more like people.

The work, which will be presented at an AAAI symposium in Arlington, Virginia, next month, is part of a broader goal to develop robots that can do a range of tasks after being guided by their owners, Muelling says.

Mind over machine: Use your brainwaves to control your computer

When it comes to controlling our computers, the last five years has seen incredible improvements in user interfaces including amazing touch screens and much more natural vocal recognition. Now, a Toronto company wants to take the UI to the next level — by going directly to the brain. You think it, and the Muse headband will make it happen under very limited circumstances.

InteraXon, the maker of the Muse headband, has listed it device on Indiegogo in hopes of raising $150,000 for building out a mass-produced headband that translates your mental commands into a computer action. The example they show on the site is playing a game using an iPad, where the rotation of a wooden block occurs when the user focuses on it. The user tilts the iPad to change the angle of the rotation.

The ideas behind the Muse are echoed in a project released by Chaotic Moon Studios earlier this year called the Board of Imagination, whereby a user controls a skateboard that connected to an iPad and a brainwave reader made by a different company called Emotiv. In that use case, the user’s focus is what makes the skateboard move forward.

Biofeedback-augmented video game helps children curb their anger

Often, when people talk about children and the psychological effects of playing video games, it’s nothing good – there are certainly plenty of individuals who maintain that if a child spends too much time blowing away virtual enemies, they will become more aggressive, antisocial people in the real world. A new game developed at Boston Children’s Hospital, however, is intended to do just the opposite. It helps children with anger problems to control their temper, so they’ll get along better with other people.

The game, appropriately called RAGE Control, requires the young player to shoot at enemy spaceships while sparing friendly ones. The child’s heart rate is monitored and displayed on the screen, via a sensor attached to one of their fingers. As long as they keep calm and their heart rate stays below a certain threshold, they can keep blasting at the spaceships. If they lose control and their heart rate goes too high, however, they lose the ability to shoot – the only way to regain that ability is to calm back down and lower their heart rate.

“The connections between the brain’s executive control centers and emotional centers are weak in people with severe anger problems,” said Dr. Joseph Gonzalez-Heydrich, co-creator of the game and senior investigator on the study. “However, to succeed at RAGE Control, players have to learn to use these centers at the same time to score points.”

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