Last Updated on July 27, 2026 by Staff
The human brain has billions of neurons but these cells are not the only ones that help the brain work properly. There are cells called microglia that are like the brain’s guardians. They keep the brain safe from infections, get rid of damaged cells and help neurons connect to each other when we are growing up.
Scientists have known for a time that human neurons take a long time to develop which gives the brain more time to build complicated networks. Now researchers at Columbia University’s Zuckerman Institute have found out that human microglia also takes time to mature.
This discovery gives us ideas about why the human brain is so good at thinking and learning. It also helps us understand brain diseases that microglia are involved in.
A Special Gene
The researchers studied a gene called SRGAP2 that is only found in humans. This gene has been interesting to scientists for over 15 years.
Unlike genes that are shared by many animals, SRGAP2 was copied many times when humans were evolving. These extra copies of the gene are only found in humans. Are thought to have helped our brains become big and complicated.
Earlier studies showed that these extra genes help neurons make connections with each other. They also slow down the development of these connections, which makes them more flexible for a time.
In this study the researchers found something unexpected. They found that the human versions of SRGAP2 are ten times more active in microglia than in neurons. This makes us wonder what role this gene plays in brain development.
Slow Development
To learn more the researchers did experiments with mice and human cells. They found a difference between the two. Humans take four to eight years to fully mature. Mouse microglia on the hand take only about three weeks.
This big difference shows that human brain development is much slower than we thought. The researchers think that this slow development helps microglia work with neurons as the brain builds its complicated networks when we are children.
This discovery also supports the idea of neoteny which’s when brain development takes a long time after we are born. Scientists think that this slow development helps us learn, remember and solve problems.
Teamwork Is Important
Microglia do more than just protect the brain from infections. Over the 20 years researchers have found that these cells are actively involved in brain development. As neurons make connections microglia help decide which ones should stay and which ones should go. This process is called pruning. It is essential for building good neural networks.
Microglia also influence how strongly neurons communicate with each other. The new findings suggest that the SRGAP2 gene helps microglia and neurons develop at the pace so they can work together.
This teamwork may allow the human brain to build more complicated neural networks than other animals.
A Future For Medicine
This research may also help us understand brain diseases better. Some studies have linked abnormal microglia activity to conditions like autism, schizophrenia, Alzheimer’s disease and other brain disorders.
If researchers can understand how SRGAP2 controls microglia development they may find ways to treat these diseases. The Columbia University team wants to study the mechanisms of SRGAP2 and how it slows down the development of microglia and neurons.
Understanding how these special human genes shape brain development may give us clues about what makes the human brain unique. While there are still questions, this discovery is an important step towards understanding the biology of human intelligence.
By showing that the brain’s immune cells take a time to mature just like neurons, this study helps us understand how evolution may have helped create the human brain’s amazing ability to learn and adapt.