A new study shows that the part of the brain that is responsible for face recognition continues to grow into adulthood in humans.
Since it is commonly accepted that brain development largely involves synaptic pruning, rather than growth, the results are surprising. The ability to recognize faces is critical for everyday social interactions, and it continues to improve from childhood to adulthood.
Jesse Gomez et al. used quantitative magnetic resonance imaging (qMRI) to compare brain tissue across individuals in an effort to understand brain activity behind facial recognition better. In a study that involved 25 adults and 22 children, the team compared qMRI data that corresponds with the respective brain regions, to recognition test results of faces and places. While the region of the brain that helps people recognize places was found to stay the same in adults, the region of the brain that helps people recognize faces was found to increase in relative size. A postmortem analysis of adult brains confirmed these results.
Using modeling to investigate the results, the team concluded that changes in myelination is not sufficient to explain this expansion of the brain region. Myelination is the fatty white substance that surrounds the axons of some nerve cells. The authors therefore propose that it may be caused by an increase in dendritic structures, cell bodies and myelin sheath.