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

itoggle caption Nelson Almeida/AFP/Getty Images

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

itoggle caption iStockphoto