Deion Jefferson, 10, and Samuel Jefferson, 7, take turns climbing and jumping off a stack of old tires at the Berkeley Adventure Playground in California. The playground is a half-acre park with a junkyard feel where kids are encouraged to "play wild." David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

In epilepsy, the normal behavior of brain neurons is disturbed. The drug valproic acid appears to help the brain replenish a key chemical, preventing seizures. David Mack/Science Source hide caption

itoggle caption David Mack/Science Source

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

The dream of epilepsy research, says neurobiologist Ivan Soltesz, is to stop seizures by manipulating only some brain cells, not all. Steve Zylius/UC Irvine Communications hide caption

itoggle caption Steve Zylius/UC Irvine Communications

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