Drug elicits anxiety-producing reactions in people without working amygdalae
S. Khalsa et al/Journal of Neuroscience 2016
In a pair of twin sisters, a rare disease had damaged the brain’s structures believed necessary to feel fear. But an injection of a drug could nevertheless make them anxious.
The results of that experiment, described in the March 23 Journal of Neuroscience, add to evidence that the amygdalae, small, almond-shaped brain structures tucked deep in the brain, aren’t the only bits of the brain that make a person feel afraid. “Overall, this suggests multiple different routes in the brain to a common endpoint of the experience of fear,” says cognitive neuroscientist Stephan Hamann of Emory University in Atlanta.
The twins, called B.G. and A.M., have Urbach-Wiethe disease, a genetic disorder that destroyed most of their amygdalae in late childhood. Despite this, the twins showed fear after inhaling air laden with extra carbon dioxide (an experience that can create the