After having Botox injections in the forehead, people’s brains respond in a different way when they see images of faces showing emotion. This may mean they find it harder to interpret other people’s emotions because of disrupted signalling between their facial muscles and their brains.
– who works at AbbVie, which makes Botox, and at the University of California, Irvine – and his colleagues scanned the brains of 10 women aged between 33 and 40 before they had injections of botulinum toxin, commonly known as Botox, to smooth wrinkles in their foreheads and again two to three weeks later. The study didn’t include any men. The injections paralysed muscles so the participants could no longer frown or smile with their whole faces.
During functional magnetic resonance imaging of their brains, the participants looked at photos of angry and happy faces interspersed with neutral images. After receiving Botox, volunteers had altered activity in a brain area called the amygdala when they looked at angry and happy faces, and in the fusiform gyrus when they looked at happy ones.
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Normally, when we see expressions, we unconsciously mimic them to help us recognise them, says at the University of South Australia. As our facial muscles copy the other person’s frown or smile, they send signals to brain areas like the amygdala and fusiform gyrus that interpret the emotions, he says.
Because Botox restricts muscle movement, it may disrupt communication between the face and the amygdala and fusiform gyrus, meaning “you might not be able to experience someone else’s emotions as intensely or vividly as you would like to”, says Marmolejo-Ramos.
AbbVie didn’t respond to a request for comment.
The finding fits with other studies showing that Botox injections can make it harder to recognise and process emotions. One study found that women who received injections in the forehead became , for example, and another found they .
Some small studies have also found that injections of Botox in the forehead can . This may be because “if you can’t frown, your face can’t send the same negative signals to your brain”, says Marmolejo-Ramos.
Scientific Reports
