How does microglia examine damaged synapses?

Mar 31, 2009

Microglia, immune cells in the brain, is suggested to be involved in the repair of damaged brain, like a medical doctor. However, it is completely unknown how microglia diagnoses damaged circuits in an in vivo brain. Japanese group led by Professor Junichi Nabekura and Dr Hiroaki Wake of National Institute for Physiological Sciences, NIPS, Japan, successfully took a live image how microglia surveys the synapses in the intact and ischemic brains of mice by using two-photon microscopic technology. They report their finding in Journal of Neuroscience on April 1, 2009.

They took an intense tune-up of their two-photon microscopy and achieved to visualize the fine structures of neurons and glias of mice in the range of 0 to 1 mm from the surface (world-leading deep imaging technology).

Surprisingly even in the normal (intact brain), microglias actively reached out their processes selectively for neuronal synapses at an interval of one hour with a contact duration of 5 minutes. More frequently microglias contacted on more active synapses. Once the brain received the damage such as ischemic infarction, microglial surveillance of synapses was much prolonged in duration, up to 2 hours. Frequently after the prolonged survey by microglia, damaged synapses were eliminated. This is the first report to show how microglia actively surveys the synapses in vivo and determines the fate of synapses, remained or eliminated

"Dynamic change of microglial surveillance of neuronal circuits in damaged brain, observed here, could contribute to establish the therapeutic approach targeted to damaged circuits", said Professor Nabekura.

Source: National Institute for Physiological Sciences

Explore further: Fruit fly study identifies brain circuit that drives daily cycles of rest, activity

add to favorites email to friend print save as pdf

Related Stories

How is our left brain is different from our right?

Nov 17, 2008

Since the historical discovery of the speech center in the left cortex in 150 years ago, functional differences between left and right hemisphere have been well known; language is mainly handled by left hemisphere, while ...

Adult brain cells are movers and shakers

Nov 08, 2007

It’s a general belief that the circuitry of young brains has robust flexibility but eventually gets “hard-wired” in adulthood. As Johns Hopkins researchers and their colleagues report in the Nov. 8 issue ...

Researchers identify a cell type that limits stroke damage

Jan 27, 2009

A research team including Serge Rivest of University Laval's Faculty of Medicine has demonstrated the existence of a type of cells that limits brain damage after a stroke. The study was recently published in the online version ...

Recommended for you

Paying closer attention to attention

2 hours ago

Ellen's (not her real name) adoptive parents weren't surprised when the school counselor suggested that she might have attention deficit hyperactivity disorder (ADHD).

User comments : 0

More news stories

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.

Ocean microbes display remarkable genetic diversity

The smallest, most abundant marine microbe, Prochlorococcus, is a photosynthetic bacteria species essential to the marine ecosystem. An estimated billion billion billion of the single-cell creatures live i ...