The area of the brain that recognizes human facial expressions has been located by researchers at Ohio State University using functional magnetic resonance imaging (fMRI). In case you were wondering, it’s on the right side of the brain behind the ear in a region called the posterior superior temporal sulcus (pSTS).

The team created a machine learning algorithm that uses the brain activity to identify what facial expression a person is looking at based on the fMRI. Results of the study are published in the Journal of Neuroscience.

The researchers used fMRI on 10 college students and monitored their brain activities as they looked at more than 1,000 pictures of people making different facial expressions, including disgusted, happily surprised, happily disgusted, angrily surprised, fearfully surprised, sadly fearful, and fearfully disgusted, according to CBS News.
The brain images showed that when the college students looked at the photographs, there was definite activity in the pSTS, the Daily Mail Online reported. The researchers found that their algorithm could accurately decode the facial expressions 60 percent of the time based on the brain activity of the person looking at the pictures.

The researchers also found that neural patterns in the pSTS recognize specific movements in a person’s face such as a furrowed brow or the upturn in the lips to form a smile.

“That suggests that our brains decode facial expressions by adding up sets of key muscle movements in the face of the person we are looking at,” said Aleix Martinez, a cognitive scientist and professor of electrical and computer engineering at OSU, in a statement.

“Humans use a very large number of facial expressions to convey emotion, other non-verbal communication signals, and language. Yet, when we see someone make a face, we recognize it instantly, seemingly without conscious awareness," continued Martinez. "In computational terms, a facial expression can encode information, and we’ve long wondered how the brain is able to decode this information so efficiently.”

Martinez called the results of their research, “a very powerful development, because it suggests that the coding of facial expressions is very similar in your brain and my brain and most everyone else’s brain.”

Assistant Psychology Professor Julie Golomb, the study co-author and director of Ohio State's Vision and Cognitive Neuroscience Lab, said the results could give researchers new insights into those with atypical neural functioning such as those with autism who may not be able to easily recognize facial expressions.

Alzheimers/Neurology Homepage