Scientists figured out how to stop your brain from feeling fear
Humanity spends a disproportionate amount of time and resources building new types of weapons that are used to do terrible things. Now it finally looks like a team of researchers who published their findings in The progress of science has developed a system that blasts people with sound waves that temporarily silence themthen their fear reactions.
The work, led by researchers at Radboud University, targeted the amygdala, the small structure thought to be the engine that drives our brain’s fear responses. It is the part of the brain that helps you quickly learn some lessons from danger. More importantly, it keeps those lessons lingering long after the threat is gone. Unfortunately, in disorders like PTSD, that lingering lesson becomes a problem that traps someone in a constant state of fear.
Using transcranial ultrasound stimulation, the researchers sent a focused, low-intensity series of sound waves through the skull to suppress amygdala activity in healthy participants for just a few moments. They then ran a controlled fear learning experiment in which pictures of snakes were paired with mild electric shocks. The idea was to teach the brain to fear something, and then see how, or if, it can unlearn that fear.
Scientists just got closer to turning off fear in the brain
The team found that when they silenced the amygdala with the sound waves, participants were slower to form fear associations in the first place. When the threat disappeared, they let go of the fear much faster than they would have done before. Now you would think that this could have the negative consequence of forgetting to fear a scary thing in the first place.
Fortunately, the researchers found that the participants’ overall ability to learn a lesson was not affected by fear, only the part directly linked to the threat. This means that the brain did not become worse at learning; it just became less attached to fear.
The team conducted a follow-up experiment, this time on the hippocampus, a nearby brain region that powers memory. It had no effect. It was a valuable test because it ruled out the idea that any brain stimulation would do the same. It doesn’t, so that means this is specifically about the amygdala.
There was a catch, however: participants whose amygdala activity was suppressed also formed less accurate memories of the threats. The researchers found that they tended to overestimate how often danger had occurred, which in itself is another valuable lesson because it suggests that the amygdala allows us to calibrate our fear responses.
This amygdala-penetrating sound wave technology could have huge implications for those suffering from PTSD and anxiety disorders, which at their core are about fear responses that refuse to shut down. Should this technique prove viable in subsequent tests, it could make the brain less effective at holding on to fear in the first place, or perhaps just better at letting go.
