Don’t freak out: memories can be erased
Did you see a scary clown this Halloween? Did you freeze or run away? Scientists have identified the part of the brain that made you react — and recorded the unpleasant memory. It also turns out we have a built-in fear of spiders and snakes!
In 10 seconds? A twin almond-shaped part of the brain called the amygdala plays a key part in our reaction to fear. Its study has enabled scientists to erase fearful memories, which can potentially treat anxiety-based disorders. (Read the science here)
How are memories of fear formed? What we see and feel is processed in our amygdala. Mouse studies have shown that ‘fear memories’ are first stored there. Using laser pulses to stimulate neurons in the amygdala of lab mice, which aren’t actually painful, scientists created a perception of pain and made the mice “fear” and avoid the chamber where it happened. (Learn more here)
But clowns? That’s just irrational fear! Good point, but this is what happens in some psychiatric disorders: we can react to threats that don’t exist in the present (or, in the case of clowns, at all). Sufferers of post-traumatic stress disorder (PTSD), for example, re-live fearful memories and react to perceivedthreats. (Read more about how fear is linked to anxiety disorders)
So how do we get rid of such perceptions? Well, scientists have hypothesised that if you find where memories are stored, then you can potentially erase them for therapy. Imagine erasing or tweaking pathological memories of fear, whilst keeping the fearful experiences that are useful for our daily survival. This can offer a way to ease the suffering of those going through debilitating fear symptoms. (Find out more)
Has anyone succeeded? Indeed! Scientists working with lab mice used a virus to ‘infect’ the neurons that stored a fearful memory with a gene that produced light-reactive proteins. They then ‘illuminated’ those neurons with low-frequency light to weaken the connections, thereby permanently erasing the fearful memory. (Read more here)
And what about the creepy crawlies? Well, it looks like the fear of snakes and spiders is hard-wired into us as an evolutionary survival aid. Researchers tested their theory on 6-month-old babies, who haven’t yet been taught to fear spiders or snakes, but they registered stressful responses nonetheless. They are now studying how this natural fear can lead to more severe phobias, so they can develop therapies. (Read the full paper here)
What happens when the amygdala is stimulated or damaged?
Traumas affecting the amygdala can cause fearful or aggressive behaviours.
Charles Whitman was considered a peaceful man, before he went on a shooting rampage in Texas in 1966, killing 17 people. He was shot dead by the police and his autopsy revealed a tumour pressing on his amygdala.
This research was curated by Miguel Briones, PhD student at The Graduate Center at City University New York, specialising in psychiatric disorders, learning and memory
Psst, Miguel distilled 17 research papers to save you 337.7 min
