Whether your fear is panicked, like in a life-or-death situation, or deliberative, like a decision about whether to take a big risk on game show, it all comes back to the amygdala. And a new study of patients with lesions on the amygdala, reported by Caltech scientists in the Proceedings of the National Academy of Sciences, suggests that damage to our brain’s fear center might turn people into reckless gamblers.
The researchers found two women with Urbach-Wiethe disease, which results in damage to the almond-shaped amygdala. Benedetto De Martinoa and his team paired those two with 12 people with undamaged brains, and presented everyone with a series of gambling tests. The study found that healthy volunteers would only opt to gamble if the potential gains were one and a half to two times the size of the potential losses [BBC News]. The women with Urbach-Wiethe, however, would keep rolling the dice as the odds got worse, and in some cases would even play if the potential loss was greater than the potential gain.
When people breathe in carbon dioxide, they start to panic. It happens in mice and other animals, too, as the body responds to the threat of suffocation. Now, in a study in Cell, researchers have connected a particular gene to that response in the brain.
The gene, called ASIC1a, is connected to a protein found in abundance in the amygdala, the area scientists believe to be the brain’s fear center. In their new study … the researchers show that mice lacking this gene don’t freeze in place–a commonly used indicator of rodent fear–to the extent that normal mice do when the team pumped CO2 into their enclosure. But when Wemmie and colleagues injected a virus containing the ASIC1a gene into the amygdala of the mice, they acted like normal mice, freezing up when exposed to elevated CO2 [ScienceNOW Daily News].