Gardening in the brain: Specialist cells prune connections between neurons

July 21, 2011
This is microglia (green) in a mouse brain. The nuclei of all cells in the brain are labeled blue. Credit: EMBL/R.Paolicelli

Gardeners know that some trees require regular pruning: some of their branches have to be cut so that others can grow stronger. The same is true of the developing brain: cells called microglia prune the connections between neurons, shaping how the brain is wired, scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, discovered. Published online today in Science, the findings could one day help understand neurodevelopmental disorders like autism.

"We're very excited, because our data shows microglia are critical to get the connectivity right in the brain," says Cornelius Gross, who led the work: "they 'eat up' to make space for the most effective contacts between neurons to grow strong."

Microglia are related to the that engulf pathogens and cellular debris, and scientists knew already that microglia perform that same clean-up task when the brain is injured, 'swallowing up' dead and dying neurons. Looking at the developing mouse brain under the microscope, Gross and colleagues found proteins from synapses – the connections between neurons – inside microglia, indicating that microglia are able to engulf synapses too.

To probe further, the scientists introduced a mutation that reduced the number of microglia in the developing mouse brain.

"What we saw was similar to what others have seen in at least some cases of in humans: many more connections between ," Gross says. "So we should be aware that changes in how microglia work might be a major factor in that have altered brain wiring."

This is a 3-dimensional reconstruction of a single microglia cell. Credit: EMBL/ R.Paolicelli

The microglia-limiting mutation the EMBL scientists used has only temporary effects, so eventually the number of microglia increases and the mouse brain establishes the right connections. However, this happens later in development than it normally would, and Gross and colleagues would now like to find out if that delay has long-term consequences. Does it affect the behaviour of the mice behaviour, for example? At the same time, Gross and colleagues plan to investigate what microglia do in the healthy adult brain, where their role is essentially unknown.

Related Stories

Recommended for you

Molecular hitchhiker on human protein signals tumors to self-destruct

July 24, 2017
Powerful molecules can hitch rides on a plentiful human protein and signal tumors to self-destruct, a team of Vanderbilt University engineers found.

Researchers develop new method to generate human antibodies

July 24, 2017
An international team of scientists has developed a method to rapidly produce specific human antibodies in the laboratory. The technique, which will be described in a paper to be published July 24 in The Journal of Experimental ...

New vaccine production could improve flu shot accuracy

July 24, 2017
A new way of producing the seasonal flu vaccine could speed up the process and provide better protection against infection.

A sodium surprise: Engineers find unexpected result during cardiac research

July 20, 2017
Irregular heartbeat—or arrhythmia—can have sudden and often fatal consequences. A biomedical engineering team at Washington University in St. Louis examining molecular behavior in cardiac tissue recently made a surprising ...

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

hush1
not rated yet Aug 28, 2011
Congratulations. Kudos

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.