Women with mild cognitive impairment, which can be a precursor to Alzheimer's, tend to decline faster than men. Lizzie Roberts/Getty Images/Ikon Images hide caption

itoggle caption Lizzie Roberts/Getty Images/Ikon Images

In this colorized image of a brain cell from a person with Alzheimer's, the red tangle in the yellow cell body is a toxic tangle of misfolded "tau" proteins, adjacent to the cell's green nucleus. Thomas Deerinck/NCMIR/Science Source hide caption

itoggle caption Thomas Deerinck/NCMIR/Science Source

"Shout, shout, let it all out. These are the things I can do without." Simone Golob/Corbis hide caption

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Nurses Katherine Malinak and Amy Young lift Louis DeMattio, a stroke patient, out of his hospital bed using a ceiling-mounted lift at the Cleveland Clinic. Dustin Franz for NPR hide caption

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The Allen Cell Types Database catalogs all sorts of details about each type of brain cell, including its shape and electrical activity. These cells, taken from the visual area of a mouse brain, are colored according to the patterns of electrical activity they produce. Courtesy of Allen Institute for Brain Science hide caption

itoggle caption Courtesy of Allen Institute for Brain Science

A color-enhanced cerebral MRI showing a glioma tumor. Scott Camazine/Science Source hide caption

itoggle caption Scott Camazine/Science Source

Colored brain scan of a 17-year-old boy with mad cow disease. The bright yellow spots are a sign that the thalamus is damaged by diseased proteins. Simon Fraser/Science Source hide caption

itoggle caption Simon Fraser/Science Source

To sleep, perchance to consolidate important connections in far-flung parts of the brain. Alberto Ruggieri/Illustration Works/Getty Images hide caption

itoggle caption Alberto Ruggieri/Illustration Works/Getty Images

The same nerve receptor that responds to the green paste on your sushi plate is activated by car exhaust, the smoke of a wildfire, tear gas and other chemical irritants. iStockphoto hide caption

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Jonathan Keleher talks with a colleague, Rafael Wainhaus, at work. Keleher was born without a cerebellum, but his brain has developed work-arounds for solving problems of balance and abstract thought. Ellen Webber for NPR hide caption

itoggle caption Ellen Webber for NPR

Prion protein can be infectious, spreading from cell to cell in the brain. Here four nerve cells in a mouse illustrate how infectious prion protein moves within cells along neurites — wire-like connections the nerve cells use for communicating with adjacent cells. Science Source hide caption

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iStockphoto

Fingertips, David Linden explains, are filled with different sorts of sensors for detecting different types of touch, including one that notes texture and fine little bumps. Another type perks up at vibration. Laughing Stock/Corbis hide caption

itoggle caption Laughing Stock/Corbis

Research into how the human brain develops helps explain why teens have trouble controlling impulses. Leigh Wells/Ikon Images/Corbis hide caption

itoggle caption Leigh Wells/Ikon Images/Corbis
Daniel Horowitz for NPR

By measuring activity in different parts of the brain, neuroscientsts can get a sense of how some people will respond to treatments. John Lund/Getty Images hide caption

itoggle caption John Lund/Getty Images