Face Recognition Relies on Surprisingly Simple Code

Posted on August 16th, 2017

Looking across a crowded theater, most of us can instantly recognize our friends, even if it’s dark or their faces are partly obscured. How exactly does the brain accomplish this feat? New research has uncovered a simple code that neurons use to process facial information.

The findings, published in Cell in June, suggest that the face-processing neurons don’t respond to a specific person. Instead, they encode specific features of faces, such as the distance between the eyes. “This new study represents the culmination of almost two decades of research trying to crack the code of facial identity,” Doris Tsao, a neuroscientist at the California Institute of Technology (Caltech), said in a news release. “It’s very exciting because our results show that this code is actually very simple.”

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In Tired Worms, Clues to Sleep

Posted on August 16th, 2017

Sleep is ubiquitous across the animal kingdom — all species assessed to date show some kind of sleep state. But no one knows the precise purpose of sleep. “Why does every neural network need some relaxation?” asks Manuel Zimmer, a neuroscientist at the Research Institute of Molecular Pathology, in Vienna, and an investigator with the Simons Collaboration on the Global Brain. “Neuroscience has a lot of good hypotheses but not a unifying clear-cut answer to why that’s the case.”

Zimmer and collaborators aim to chip away at this question using newly developed techniques to monitor the whole brain in the microscopic round worm C. elegans as it falls asleep and wakes up. “That makes it possible to watch how the brain switches between these drastically different states,” Zimmer says.

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In Fruit Fly Brain, A Ring for Navigation

Posted on August 16th, 2017

The arbors of compass neurons in the ellipsoid body are labeled in different colors. Credit: Tanya Wolff, Nirmala Iyer & Gerry Rubin.

The arbors of compass neurons in the ellipsoid body are labeled in different colors.
Credit: Tanya Wolff, Nirmala Iyer & Gerry Rubin.

If you slowly turn around with your eyes closed, chances are you’ll be able to keep track of which direction you’re facing. Neurons known as head-direction cells use a combination of past sensory knowledge and your own movement to calculate where you are, even in the absence of visual information.

But how does the brain generate these persistent internal representations? New research from Vivek Jayaraman, Shaul Druckmann and collaborators at the Janelia Research Campus in Ashburn, Virginia, outlines a potential mechanism. The findings show that in fruit flies, an internal sense of direction is maintained by what’s known as a ring attractor network.

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How Many Cells Are Needed for an Accurate Picture of Neural Activity?

Posted on June 28th, 2017

Scientists can routinely track the activity of hundreds — sometimes even thousands — of neurons in the brain of awake animals. But how many cells do they need to monitor to truly understand how the brain functions? That question has become a hot topic among researchers doing large-scale neural recordings. The answer could shape the future of the field, influencing how scientists design experiments and new technologies.

The Dimension Question: How High Does It Go?

Working-Memory Research Uncovers Essential Role for Thalamus

Posted on June 28th, 2017

A trio of papers published in May suggest that short-term memory depends on interactions between the cortex and thalamus, a subcortical brain region that connects to many parts of the brain. Previous research had suggested that the cortex generates and maintains the neural activity thought to underlie working memory. But the new findings show that the thalamus is essential, changing the notion of how working memory works.

Working-Memory Research Uncovers Essential Role for Thalamus

Deciphering Scent: How We Untangle the Tapestry of Odors

Posted on April 26th, 2017

Walk into a diner around breakfast time, and you’re likely to be hit with an array of enticing odors — steaming coffee, freshly baked muffins, bacon sizzling on the grill. Given that each of these smells is made up of a mix of different volatile compounds all hitting our olfactory system at the same time, how does our brain discern the identity of the different foods?

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Coming Soon: Routine Recording From Thousands of Neurons

Posted on April 26th, 2017

When Jason Chung woke up early on December 22 of last year, he opted to avoid his morning coffee. The graduate student would need steady hands for the grueling 18-hour surgery ahead of him, his first attempt at implanting more than 1,000 electrodes in a tiny rat brain. Over the course of the day, he would perform 10 tiny craniotomies, each opening implanted with one or more 64-electrode probes. Chung, who works in Loren Frank’s lab at the University of California, San Francisco, would soon be able to simultaneously record from hundreds of neurons across the brain.

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Noninvasive Tool Controls Neurons

Posted on March 13th, 2017

Optogenetics — a tool that enables researchers to control neurons with light — has transformed neuroscience. But the technique is invasive. Light is typically delivered via a fiber optic cable implanted in an animal’s brain. Researchers have developed a noninvasive alternative: a genetic system for controlling neurons that uses radio waves or magnetic fields instead of light. These signals can freely penetrate tissue, meaning the technique can be used on awake, behaving animals without invasive delivery systems.

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How Practice Makes Perfect: Dopamine Clues From a Songbird

Posted on February 23rd, 2017

Rumor has it that the great pianist Arthur Rubinstein was taking a walk in New York City one day when a pedestrian approached him and asked, “How do I get to Carnegie Hall?” Rubinstein pondered this question for a moment and replied, “Practice!” Indeed, many of our motor skills, whether playing tennis or playing the piano, are not innately programmed but acquired through a process of trial and error.

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New Genetically Engineered Sensors Enhance Brain-Wide Monitoring

Posted on February 17th, 2017

Over the past two decades, scientists’ ability to track neural activity with light has changed the face of neuroscience. Using genetically encoded calcium indicators, scientists can simultaneously monitor thousands of neurons, granting a much broader view of brain activity than was previously possible. “Now we can see the brain producing this beautiful symphony,” says Vincent Pieribone, a neuroscientist at Yale University.

But ever since these indicators were first developed, scientists have been striving to make them better. They want sensors that are brighter or glow in different colors, operate faster or slower, or can target different locations. Scientists presented their newest engineering advances at the third annual meeting of BRAIN Initiative investigators, held in Bethesda, Maryland, in December. They described calcium sensors that fluoresce in red, far-red and near infrared, as well as sensors designed to directly monitor changes in voltage. Whereas implanted electrodes can directly measure voltage changes in the brain, genetically engineered sensors have the potential to measure orders of magnitude more cells and to do so less invasively.

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