In a recent study led by Cedars-Sinai, researchers have found new information about how the part of the brain responsible for memory is activated when the eyes come to rest on a face versus another object or image. Their findings, which were published in the peer-reviewed journal Science Advances, add to already established scientific understanding of how memory works, and to evidence supporting a future treatment targeted for memory disorders.
While vision feels continuous, people move their eyes from one distinct spot to another three to four times per second. In this study, researchers found that when the eyes land on a face, certain cells in the amygdala, a part of the brain that processes social information, react and trigger memory-making activity.
“You could easily argue that faces are one of the most important objects we look at,” said Ueli Rutishauser, PhD, director of the Center for Neural Science and Medicine at Cedars-Sinai and senior author of the study. “We make a lot of highly significant decisions based on looking at faces, including whether we trust somebody, whether the other person is happy or angry, or whether we have seen this person before.”
The study was conducted using 13 epileptic patients who had electrodes implanted in their brains and were then shown images varying from human faces to geometric figures to cars to flowers while having a camera trained on their eyes to determine what they were looking at. In addition the researchers also recorded the patient’s theta wave activity. Theta waves are a distinct electrical brain wave that is created in the hippocampus and they are key in processing information and forming memories.
Researchers showed the patients the images in two sessions and found that each time the participants’ eyes landed on a human face, certain cells in the amygdala fired. Every time these “Face Cells” fired the pattern of theta waves in the hippocampus reset or restarted.
“We think that this is a reflection of the amygdala preparing the hippocampus to receive new socially relevant information that will be important to remember,” said Rutishauser, the Board of Governors Chair in Neurosciences and a professor of Neurosurgery and Biomedical Sciences.
Interestingly, the researchers showed that the more quickly a subject’s face cells fired when their eyes fixed on a face, the more apt the subject was to remember that face. When a subject’s face cells fired more slowly, they were more likely to forget the face they had seen.
Subjects’ face cells also fired more slowly when they were shown faces they had seen before, suggesting those faces were already stored in memory and the hippocampus didn’t need to be activated.
Rutishauser said these results suggest that people who struggle to remember faces could have a dysfunction in their amygdala, noting that this type of dysfunction has been implicated in disorders related to social cognition, such as autism.
The results also indicate the importance of both eye movements and theta waves in the memory process, Rutishauser said.
To read the original article click here: https://www.sciencedaily.com/releases/2022/03/220318161429.htm