Klotho (right) is one of the three Greek Fates depicted in this Flemish tapestry at the Victoria and Albert Museum in London. Wikimedia Commons hide caption

itoggle caption Wikimedia Commons

People smoke marijuana, presumably, because it affects their brains, not despite that fact. Above, people in Sao Paulo, Brazil, campaign for the legalization of marijuana. Nelson Almeida/AFP/Getty Images hide caption

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Images of the developing fetal brain show connections among brain regions. Allen Institute for Brain Science; Bruce Fischl, Martinos Center for Biomedical Imaging, Massachusetts General Hospital hide caption

itoggle caption Allen Institute for Brain Science; Bruce Fischl, Martinos Center for Biomedical Imaging, Massachusetts General Hospital

Researchers say intervention in early childhood may help the developing brain compensate by rewiring to work around the trouble spots. iStockphoto hide caption

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A computer designed by hobbyists to look like a brain on display at a Berlin fair in 2012. What happens when we go from crude models to complete working simulations of this all-important organ? Britta Pedersen/DPA/AFP/Getty Images hide caption

itoggle caption Britta Pedersen/DPA/AFP/Getty Images

The brain edits memories of the past, updating them with new information. Scientists say this may help us function better in the present. But don't throw those photos away. iStockphoto hide caption

itoggle caption iStockphoto