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

itoggle caption iStockphoto

The Allen Institute for Brain Science hosted its first BigNeuron Hackathon in Beijing earlier this month. Similar events are planned for the U.S. and U.K. Courtesy of Allen Institute for Brain Science hide caption

itoggle caption Courtesy of Allen Institute for Brain Science

The effects of malaria in the brain are clear: A healthy brain, right, has many grooves and crevices. But when the brain swells up, left, these crevices smooth out. Courtesy of Michigan State University hide caption

itoggle caption Courtesy of Michigan State University

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

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

Greg O'Brien (left), with Colleen, Mary Catherine, Conor, and Brendan O'Brien, has been grappling with Alzheimer's disease for the last five years. Courtesy Greg O'Brien hide caption

itoggle caption Courtesy Greg O'Brien

In sighted people, the part of the brain that recognizes faces is linked to the brain's visual system. But in blind people it seems wired to circuits that process sound. Tina Zellmer/Ikon Images/Corbis hide caption

itoggle caption Tina Zellmer/Ikon Images/Corbis

A tangle of protein (green) in this scanning electron micrograph of a brain cell of an Alzheimer's patient lies within the cytoplasm (blue) of the cell. The tangle consists of clumps of a toxic form of tau. Thomas J. Deerinck/Corbis hide caption

itoggle caption Thomas J. Deerinck/Corbis