Scientists use AI to show how the brain processes emotions7. April 2020
Scientists use AI to show how the brain processes emotions
Scientists at the Max Planck Institute for Neurobiology in Germany recorded the faces of laboratory mice when they were exposed to various stimuli such as sweet aromas and electric shocks. Using machine learning algorithms, the researchers then analyzed how the faces of the rodents changed when they felt different emotions.
The software showed that their facial muscles subtly shifted when their feelings changed. Mice that felt pain pulled their ears back and puffed up their cheeks, while mice that felt pleasure pushed their jaws and ears forward and pulled their nose towards their mouth.
The artificial intelligence also showed that their expression changed depending on how they felt before receiving the stimuli. For example, when a thirsty mouse received a sugary drink, its face showed more joy than a rodent whose thirst had already been quenched.
The researchers then investigated which brain cells triggered these reactions using a technique called optogenetics, which uses light to stimulate different neurons. They found that when the mice targeted neurons known to trigger different emotions, they showed the associated facial expressions.
The idea that facial expressions reveal how the brain processes emotions is not new. Charles Darwin suggested in 1872 that humans and animals communicate their emotions through similar expressions. Thanks to recent developments in AI, we can now put his theory to the test.
“I was fascinated by the fact that we humans have emotional states that we experience as feelings,” neuroscientist Nadine Gogolla, who led the three-year study, told the journal Nature. “I wanted to see if we could learn from animal experiments how these states develop in the brain.”
Gogolla’s team trained the software to recognize the reactions of the mice by feeding them images of their facial expressions labeled with the emotion associated with them. They then gave the system untagged images and asked it to decode the emotions on display. The AI was able to identify the emotions with 90% accuracy.
The researchers believe that their findings on how neurons trigger facial reactions in rats will help us understand how human brains process anxiety disorders and depression. And maybe they can finally prove whether Darwin was right all along.