Researchers at The Ohio State University have pinpointed the area of the brain responsible for recognizing human facial expressions. It’s on the right side of the brain behind the ear, in a region called the posterior superior temporal sulcus (pSTS).
In a paper published today in the Journal of Neuroscience, the researchers report that they used functional magnetic resonance imaging (fMRI) to identify a region of pSTS as the part of the brain activated when test subjects looked at images of people making different facial expressions.
Further, the researchers have discovered that neural patterns within the pSTS are specialized for recognizing movement in specific parts of the face. One pattern is tuned to detect a furrowed brow, another is tuned to detect the upturn of lips into a smile, and so on.
The team was able to create a machine learning algorithm that uses this brain activity to identify what facial expression a person is looking at based solely on the fMRI signal.
Using this fMRI data, the researchers developed a machine learning algorithm that has about a 60 percent success rate in decoding human facial expressions, regardless of the facial expression and regardless of the person viewing it.
The researchers will continue the work, which was funded by the National Institutes of Health and the Alfred P Sloan Foundation.