You can learn to switch on these hidden cells to unlearn fear
Researchers were shocked to find out that fear-suppressing cells hide in a region of the brain
Learned fears can be activated or suppressed by tampering with cells in the brain, neuroscientists have discovered.
A heart-pounding fear of sharks, for example, which rises from the deep (like the toothy star of Jaws) and takes you by surprise, could be controlled by neurons that activate or suppress fearful memories.
Neuroscience professor Michael Drew, from the University of Texas, said: “Since the time of Pavlov and his dogs, scientists have known that memories we thought we had put behind us can pop up at inconvenient times, triggering … a form of relapse. What they didn’t know was why it happened.”
Now his team has found that when “extinction neurons” are activated, they suppress fearful memories. These fears return when they are not active.
Learned fear is distinct from innate fear, which typically controls the freeze or flee response when we run into danger and is triggered by no prior encounters.
The researchers were astonished to find out the fear-suppressing group of cells hid in a region of the brain known as the hippocampus, after doing experiments with mice using a harmless shock in a box.
“Traditionally, scientists associate fear with another part of the brain, the amygdala,” said Drew, senior author of the study.
“The hippocampus seems to play an important role in contextualising fear, for example, by tying fearful memories to the place where they happened.”
This could shed light on why exposure therapy – which promotes forming new memories of safety that override an old fear – may “sometimes stop working”, he suggested.
If you’re afraid of snakes, for example, you may let a harmless snake slither over your foot to create safe “extinction” memories. They do not eliminate the original fear. Instead, they create a new memory that competes with or inhibits the fearful memory.
These findings could lead to new recommendations about how often and when exposure therapies were used to treat anxiety, phobias and post-traumatic stress disorder.
New technology has the potential to transform the way fears such as claustrophobia or flying are treated, Dutch researchers reported last week.
They did an experiment treating a fear of heights using virtual reality with no therapist involved.
Using a smartphone app and basic VR viewer, the self-guided ZeroPhobia treatment made a significant impact on participants’ fear of heights.
Two to five in 100 people are scared of heights, and this treatment, based on cognitive behavioural therapy, costs less “than a few coffees from Starbucks”, said clinical psychologist Dr Tara Donker.
Putting people safely near the source of their fear and gradually exposing them in a virtual environment – for example, standing on top of the building – gives them a chance to safely face and reduce their fear.
Donker said: “People are more willing to try new things out because they know it is not real, and because the treatment is entirely gamified and animated, they may even enjoy it.”
And then there are people who stare down fear in reality – rather than the virtual world – to pursue their passion, such as polar swimmer and eco-activist Lewis Pugh, who has swum past a polar bear in the Arctic Circle.
Asked about why he trained in False Bay off Cape Town at night, when sharks are known to hunt, he said: “If I don’t have the courage to swim in False Bay at night, I would never be able to swim with polar bears in the Arctic, or leopard seals and orcas in the Antarctic. Courage is like a muscle – it needs to be exercised.”
His extinction neurons must be working overtime.