Children await treatment at a medical facility in St. Marc, northern Haiti, amid a cholera epidemic that has claimed more than 100 lives and infected more than 1,000 people over the past few days. Thony Belizaire/AFP/Getty Images hide caption

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Scientists exposed the brains of specially engineered lab mice to pulses of light and saw brain cells responding as if they were triggered by an odor. The research could be applied to diseases including Alzheimer's and Parkinson's. Eric Isselee/ hide caption

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Defense and Veterans Brain Injury Center via Technology Review

Scientists found that neurons (red) are able to leak signaling chemicals to nearby cells. The finding may help explain the cause of some nervous system conditions, including epilepsy and chronic pain. Institute for Stem Cell Research/Getty Images hide caption

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A slice of Hurricane Karl was captured by NASA's CloudSat satellite. The clouds were just over 8 miles high. hide caption

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A type of imaging called functional connectivity MRI provides scientists with a new lens for studying brain development. In this image, the thickness of each connection indicates its relative weight in the prediction of brain maturity.  Functional connections that grow stronger with maturation are orange, while those that weaken with maturation are green. Science/AAAS hide caption

itoggle caption Science/AAAS