Surprising Findings on Brain Development during Adulthood

A group of scientists at the Stanford University School of Medicine in California discovered that the region of the brain responsible for face recognition grows in children as well as in adults. The discovery surprised scientists because it was widely believed that brain development in adulthood didn’t involve tissue growth but neuroplasticity instead. Until now, it was thought that brain development occurred exclusively through a process called synaptic pruning – a mechanism of destruction of the synapses (connections between the neurons) that are rarely used, thus clearing room for the development of stronger and more effective synapses. But the new findings suggest there’s much more going on.

A growing fusiform gyrus

This is the first time that research has found evidence that tissue in this region of the brain, called fusiform gyrus, increases in size from childhood to adulthood. Previous research suggested that most changes in brain tissue occurred during childhood (within first two years) and involved either synaptic pruning or tissue changes. To make the discovery, which will force science to rethink the anatomical development of the brain over the years, researchers recruited 22 children and 25 adults. The participants were subjected to visual recognition tests of faces and places, functional magnetic resonance, and quantitative magnetic resonance imaging tests.

Functional magnetic resonance imaging (FMRI) was used to identify the brain regions activated during facial recognition tasks and during site recognition activities. With quantitative magnetic resonance imaging, scientists measured the amount of brain tissue present in those regions. When comparing the results obtained in children and adults, it was observed that the area responsible for face recognition continues to grow in size and density in adults. The same, however, does not occur in the area responsible for recognizing places.

PhD student Jesse Gomez, who was involved in the study, says that the observed enlargement of the fusiform gyrus area cannot be accounted for myelination alone. Therefore, the observations suggest that cortical tissue proliferation is taking place. Subsequent examination of postmortem brains validated Gomez team’s observations. The findings are coherent with the previous observations that adults tend to recognize faces better than children. Professor Kalanit Grill-Spector suggests that since adults carve progressively deeper and more complex social interactions throughout life, additional neurological facilities for facial processing become a necessity.

Medical implications

Scientists highlight that this finding could be useful in the future to examine how the brain changes with aging, and to understand how the physiology of the fusiform gyrus may affect neurological phenomena such as dyslexia, synaesthesia, face hallucinations, and prosopagnosia. However, more studies are necessary to empirically confirm the findings and remove other possible causal links.