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Watch a Neuroscientist Explain a Concept in 5 Levels of Difficulty

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In this WIRED video, neuroscientist Bobby Kasthuri explains the concept of a connectome to a series of people with differing levels of experience. The goal is that each person should come away with an understanding of the concept. The challenge, of course, is in tailoring the explanation to each individual.

Kasthuri starts with a 5-year-old, going for the basics. It's fascinating to watch as he then repeats the process, adapting on the fly, for a 13-year-old, a college student (who studies science), a neuroscience grad student, and a practicing neuroscientist.

There are two reasons to watch this video. First, it's instructive to watch how Kasthuri models his audience's mind and adapts his discussion to fit. Second, you get to learn what a connectome is, which is in itself quite cool. Tune in:

If you just want to learn more about the connectome, read this article.

[h/t: Kottke.org.]

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Scientists Identify Cells in the Brain That Control Anxiety
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People plagued with the uncomfortable thoughts and sensations characteristic of anxiety disorders may have a small group of cells in the brain to blame, according to a new study. As NPR reports, a team of researchers has identified a class of brain cells that regulates anxiety levels in mice.

The paper, published in the journal Neuron, is based on experiments conducted on a group of lab mice. As is the case with human brains, the hippocampus in mouse brains is associated with fear and anxiety. But until now, researchers didn't know which neurons in the hippocampus were responsible for feelings of worry and impending danger.

To pinpoint the cells at work, scientists from Columbia University, the University of California, San Francisco, and other institutions placed mice in a maze with routes leading to open areas. Mice tend to feel anxious in spacious environments, so researchers monitored activity in the hippocampus when they entered these parts of the maze. What the researchers saw was a specialized group of cells lighting up when the mice entered spaces meant to provoke anxiety.

To test if anxiety was really the driving factor behind the response, they next used a technique called optogenetics to control these cells. When they lowered the cells' activity, the mice seemed to relax and wanted to explore the maze. But as they powered the cells back up, the mice grew scared and didn't venture too far from where they were.

Anxiety is an evolutionary mechanism everyone experiences from time to time, but for a growing portion of the population, anxiety levels are debilitating. Generalized anxiety disorder, social anxiety disorder, and panic disorder can stem from a combination of factors, but most experts agree that overactive brain chemistry plays a part. Previous studies have connected anxiety disorders to several parts of the brain, including the hippocampus, which governs memory as well as fear and worry.

By uncovering not just how the brain produces symptoms of anxiety but the individual cells behind them, scientists hope to get closer to a better treatment. There's more work to be done before that becomes a possibility. The anxiety cells in mice aren't necessarily a perfect indicator of which cells regulate anxiety in humans, and if a new treatment does eventually come from the discovery, it will be one of many options rather than a cure-all for every patient with the disorder.

[h/t NPR]

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Medicine
Wilder Penfield: The Pioneering Brain Surgeon Who Operated on Conscious Patients
Public Domain, Wikimedia Commons
Public Domain, Wikimedia Commons

For centuries, epilepsy was a source of mystery to scientists. Seizures were thought to be caused by everything from masturbation to demonic possession, and it wasn’t until the 1930s that a neurosurgeon showed the condition could sometimes be boiled down to specific spots in the brain. To do it, he had to open up patients’ heads and electrocute their brain tissue—while they were still conscious.

Wilder Penfield, the subject of today’s Google Doodle, was born on January 26, 1891 in Spokane, Washington. According to Vox, the Canadian-American doctor revolutionized the way we think about and treat epilepsy when he pioneered the Montreal Procedure. The operation required him to remove portions of the skulls of epilepsy sufferers to access their brains. He believed seizures were connected to small areas of brain tissue that were somehow damaged, and by removing the affected regions he could cure the epilepsy. His theory was based on the fact that people with epilepsy often experience “auras” before a seizure: vivid recollections of random scents, tastes, or thoughts.

To pinpoint the damaged brain tissue, he would have to locate the part of the brain tied to his patient’s aura. This meant that the patient would need to be awake to tell him when he struck upon the right sensation. Penfield stimulated the exposed brain tissue with an electrode, causing the patient to either feel numbness in certain limbs, experience certain smells, or recall certain memories depending on what part of the brain he touched. A local anesthetic reduced pain in the head; shocking the brain didn’t cause any pain because the organ doesn’t contain pain receptors.

During one of his surgeries, a patient famously cried, “I smell burnt toast!” That was the same scent that visited her before each seizure, and after Penfield removed the part of her brain associated with the sensation, her epilepsy went away.

Brain surgery isn’t a cure-all for every type of epilepsy, but treatments similar to the one Penfield developed are still used today. In some cases, as much as half of the brain is removed with positive results.

[h/t Vox]

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