Woman lacking basic brain structure isn't scared of anything
A middle-aged woman known as SM blithely reaches for poisonous snakes, giggles in haunted houses and once, upon escaping the clutches of a knife-wielding man, didn’t run but calmly walked away. A rare kind of brain damage precludes her from experiencing fear of any sort, finds a study published online December 16 in Current Biology.
SM has an unusual genetic disorder called Urbach-Wiethe disease. In late childhood, this disease destroyed both sides of her amygdala, which is composed of two structures the shape and size of almonds, one on each side of the brain. Because of this brain damage, the woman knows no fear, the researchers found.
Experiments have strongly implicated the amygdala in fear processing. Many of these were conducted on animals with amygdala damage. “But one thing we’ve never known for sure, because they’re animals, is whether they can consciously feel fear,” says study coauthor Justin Feinstein of the U