Many times we have found ourselves in front of a mountain whose rocks were shaped like a human face, or we know stories like that of the woman who thought she saw Jesus in the tortilla she was about to eat. But, what is the mechanism by which our brain makes sure whether or not what we see is a real face?
A study conducted at the Massachusetts Institute of Technology indicates that both hemispheres of the brain play a role in the facial recognition process, but each fulfills a different function. While the left fusiform gyrus informs how similar the one-sided image is, it is nevertheless the right that offers the final verdict.
To demonstrate this effect, the scientists used magnetic resonance imaging of the brain of the participants in the experiment, who were shown photographs of faces, objects that looked like it, and others that had nothing to do with it. They observed that the activity patterns of the left hemisphere gradually changed as the images became more or less like a face. In contrast, changes were detected on the right side only if the image showed a real face. When it was not, the patterns of activity remained constant, regardless of whether the object more or less resembled a face. In addition, the activation of the left part of the fusiform gyrus preceded the right one by a few seconds, so it seems that it would be the left hemisphere that would do the first work and pass the information to the right.
Scientists hope to get more evidence on the relationship between the cerebral hemispheres through the use of electroencephalography and magnetoencephalography, technologies that can offer a much more precise view on the coordination of brain activity.
