The human brain tissue responsible for helping us distinguish one face from another keeps growing long after adolescence, findings of a new study have revealed.
Brain Area Responsible For Face Recognition Continues To Expand
It is previously thought that the growth of brain tissues stops early in life and that the brain adapts in later life by tweaking the connections between the neurons.
MRI scans of 22 children and 25 adults, however, found that the parts of the brain devoted to facial recognition expanded from childhood to adolescence unlike other regions of the brain responsible for recognizing other objects. The discovery can help explain why people's ability to recognize faces improves until about age 30.
For the new study published in the journal Science, Stanford University graduate student in neurosciences Jesse Gomez and colleagues monitored the brain activity of the study participants while the latter looked at different pictures.
The scans, which highlighted the size and location of the brain regions responsible for recognizing faces and other objects, revealed notable change at the fusiform gyrus, home of the brain tissue that helps tell one face from another.
The scans revealed that from childhood to adulthood the amount of brain tissue responsible for face recognition increased by 12.6 percent but there were no differences between children and adults in other areas of the brain that respond to places and other objects instead of faces.
When they conducted memory tests in which the participants were to pick out familiar faces, the researchers found that the participants who had more tissue in the fusiform gyrus scored the highest.
"This tissue development is correlated with specific increases in functional selectivity to faces, as well as improvements in face recognition, and ultimately leads to differentiated tissue properties between face- and place-selective regions in adulthood," Gomez and colleagues wrote in their study, which was published on Jan. 6.
Becomes Denser With Structures That Connect And Support Neurons
Gomez said that the brain area responsible for face recognition did not require more neurons but rather became more densely populated with structures connecting and supporting brain cells. He explained this concept by using a flower garden to show how this area of the brain continuous to develop past adolescence.
"You can imagine a 10-foot by 10-foot garden, and it has some number of flowers in there," Gomez said. "The number of flowers isn't changing, but their stems and branches and leaves are getting more complex."
Why Brain Area That Recognizes Faces Keeps Growing
Kalanit Grill-Spector, a psychology department professor at Stanford, explained that the continuing growth in brain areas involved in facial recognition may be a response for the need to recognize increasing number of faces as children grow older.
Children recognize their family and a small number of friends but by the time they get to high school or college, their social group expands to up to hundreds of people, which would require improved ability to tell one person to another. Grill-Spector said that recognizing all these people needs a lot of brain power given that faces have the same configuration and features.