Botox can affect emotional processing

We reflect other people’s emotions through an ingrained, unconscious process. According to the facial feedback hypothesis, seeing a happy or angry face would make us contract or relax the appropriate face muscles to emulate that expression and better identify and experience the associated emotion. Since botox impairs some facial muscles from contracting in response to certain facial expressions, a group of researchers wondered whether it would also affect emotional processing.

To test their hypothesis, they injected Botox to (temporarily) paralyse the muscle which causes frowning in 10 women aged 33–40 years old and measured their brain activity when looking at faces displaying different emotions.

Using functional magnetic resonance imaging, a technique which allows inferring brain activity based on blood flow and oxygenation, the researchers aimed to explore changes to emotional processing two weeks after botox injections.

As they show in their paper in Scientific Reports ¹, botox caused changes in the responses to happy and angry faces of the amygdala, a region responsible for emotional processing, as well as in the response of the fusiform gyrus –related to object and facial recognition– to happy faces.

These results indicate that paralysing the facial muscle responsible for frowning with botox affects emotional processing, thus adding weight to the facial feedback hypothesis. Previous research also suggested inhibited emotional perception after botox injections to the forehead and to get rid of crow’s feet compared to simply using a dermal filler.

Although the researchers used botox as a tool to demonstrate their hypothesis, being such a common cosmetic procedure, it raises the question whether the obsession with youth will do away with more than our facial expression but also remove our ability to empathise and recognise other people’s emotions. Will those botox “face masks” make us robot-like?