Brain Connection Pruning Occurs Earlier in Girls than Boys, Researchers Find

Long distance brain connections get pruned earlier in girls than in boys, a new research from Newcastle University found. This early snipping may explain why girls mature faster than boys of the same age.

Researchers found that this 'pruning' actually helps brain increase its efficiency.

Brains of young children have unnecessary connections that get snipped when they reach puberty. Previous research has shown that the synaptic pruning continues to occur in the brains of adults who are in their 20s. Other research has shown that a specialized group of cells called as the microglia act as the 'gardeners of the brain'.

The study was based on 121 participants between ages 4 and 40. Using diffusion tensor imaging, researchers found that the brain connections were getting streamlined. The pruning started at age 10 for girls while for the boys it started at around age 20.

"Long-distance connections are difficult to establish and maintain but are crucial for fast and efficient processing. If you think about a social network, nearby friends might give you very similar information - you might hear the same news from different people. People from different cities or countries are more likely to give you novel information. In the same way, some information flow within a brain module might be redundant whereas information from other modules, say integrating the optical information about a face with the acoustic information of a voice is vital in making sense of the outside world," Dr Marcus Kaiser, one of the study authors, said in a news release.

The study is published in the journal Cerebral Cortex.

The team also found that not all connections were pruned, some short-range connections, such as those that exist between vision and sound, were preserved. The short connections help the brain get quick access to information.

"The loss of connectivity during brain development can actually help to improve brain function by reorganizing the network more efficiently. Say instead of talking to many people at random, asking a couple of people who have lived in the area for a long time is the most efficient way to know your way. In a similar way, reducing some projections in the brain helps to focus on essential information," Ms Sol Lim, also an author of the study said in a news release.