The surprising side effect of Botox on the brain


In today’s society, image and physical appearance have become an increasingly common obsession. Hence the proliferation of cosmetic treatments and products, including the very popular Botox.

With the scientific name of botulinum toxin, this substance is a natural neurotoxin produced by the bacteria Clostridium botulinumwhich appears in poorly preserved foods and causes food poisoning.

A poison with therapeutic effects

Botulinum toxin’s mechanism of action is based on its ability to block the release of acetylcholine, a neurotransmitter essential for muscle contraction. As a result, the muscle temporarily relaxes and loses its ability to produce involuntary contractions or spasms.

In aesthetic medicine, this paralyzing effect is used to reduce expression lines.

Despite the fact that its use is associated with sometimes unfortunate cosmetic touch-ups, Botox is also used to combat various disorders, including muscle spasms, chronic migraines, urinary incontinence and excessive sweating, among others. It is therefore considered a safe and effective substance when administered by a professional.

However, a recent study from the University of Irvine (California) suggests a surprising side effect of Botox on the processing of emotions. Its origin would be in the most basic mechanisms used by the brain to recognize the expressions of the people around us.

The value of microexpressions

Without the mediation of speech and simply by using a varied repertoire of grimaces, smiles, frowns, blinks and eye gestures, an infinite number of emotions can be communicated, such as fear, anger, sadness and happiness. Also social and status information, such as submission or aggression.

Thus, facial expressions – especially micro-expressions, which last only a fraction of a second – can reveal emotions to our interlocutors before we even consciously know what we are feeling.

But what if our ability to gesture is reduced? Obviously, we could think of a communication barrier. This became clear during the covid-19 pandemic, when the widespread use of masks had a negative impact on the quality of social interactions.

Similarly, Botox decreases the mobility of facial muscles, limiting our ability to express our emotions naturally and fully.

So far everything seems logical, but it is also that the aforementioned work describes an astonishing effect on the ability of the person who receives botulinum toxin to recognize and interpret the emotions of others.

What if we can’t frown?

To understand how our own gestures affect emotional interpretation, researchers measured the brain activity of 10 women aged 33 to 40 who were injected with Botox to induce temporary paralysis of the muscle responsible for frowning, known as the glabellar muscle.

The researchers recorded the brain activity of these volunteers as they looked at pictures of faces showing different emotions (happy, sad, angry, etc.) before and after receiving the treatment. Unexpectedly, the results showed changes in the activity of the amygdala, a key brain region for recognizing and interpreting emotions.

How is it possible? The authors of the book suggest that restricting our own gestures could hamper what is called facial feedback. According to this theory, when we see an angry or happy face, we contract or flex the corresponding muscles to recreate the expression and help us identify the reflected emotion.

Thus, preventing frowns with Botox would prevent the formation of these microexpressions, affecting the processing of emotional faces.

The study adds new evidence to a growing line of thought suggesting that inhibiting glabellar muscle contraction alters neural activity involved in emotional processing. In addition, these results help us better understand how the brain interprets emotions.

The ability to correctly read the gestures of others is essential for effective communication and social interaction. To the point that defects in facial expression recognition are considered one of the main symptoms of social disorders, such as autism.

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Problems interpreting social cues can make it difficult to build relationships and build a strong social network. While more research is needed to confirm the results and better understand Botox’s role in interpreting emotions, it’s important to weigh its potential (and unexpected) side effects when considering Botox treatments.

This article originally appeared on The Conversation. Read the original.

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