Scientists Map Human Brain: Emotions Revealed in New Model

How do you feel? Scientists may be able to tell exactly just that by mapping your brain. For the first time, researchers have identified exactly which emotion a person is experiencing based only on brain activity.

Actually identifying emotions in the brain isn't an easy task. Previous studies have tried to tackle it, but methods have been unreliable. Some people don't like to say exactly what emotion they're feeling, or have trouble expressing any mixed feelings that they may have. In addition, it's difficult to elicit the same response from someone time and time again in order to test a specific emotion.

Yet this particular study doesn't rely on people to self-report themselves. Instead, it developed a different method. It developed a computational model that identifies individuals' thoughts of concrete objects, often dubbed "mind reading." This particular method was built on previous discoveries in this area.

Yet there still remained the problem of eliciting emotional responses from volunteers. In the end, the scientists decided to use actors, who are adept at cycling through ranges of emotions. The researchers recruited 10 actors who were scanned while viewing the words of nine emotions: anger, disgust, envy, fear, happiness, lust, pride, sadness and shame. While inside the fMRI scanner, the actors were asked to enter each of these emotional states multiple times, in random order.

That's not all the scientists had these actors do, though. In order to ensure that the technique was actually measuring emotions, the researchers had the actors look at pictures of neutral and disgusting photos that they had not seen before. The computer model, constructed from using statistical information to analyze the fMRI activation patterns gathered for 18 emotional words, had learned the emotion patterns from self-induced emotions and was able to correctly identify the emotional content of photos being viewed.

In order to actually map these patterns, though, the researchers used the participants' neural activation patterns in early scans to identify emotions experienced in later ones. The computer model actually achieved a rank accuracy of .84 for identifying emotions. Then the team took the machine learning analysis to guess the emotions the actors experienced when seeing the disgusting photographs. The model achieved a rank accuracy of .91.

"Despite manifest differences between people's psychology, different people tend to neutrally encode emotions in remarkably similar ways," said Amanda Markey, one of the researchers, in a news release.

The researchers weren't only able to map these emotions, though. They also found that emotion signatures aren't necessarily limited to specific brain regions. Instead, they produce characteristics patterns throughout a number of brain regions.

In the future, the researchers plan to use this new identification method in order to overcome a number of challenging problems in emotion research, including identifying emotions that individuals are actively trying to suppress.

The findings are published in the journal PLOS One.