Fruit flies have helped researchers in the US better understand the impact of small brain injuries on the nervous system.
Scientists from Oregon Health & Science University (OHSU) used the flies to examine how damage to a small amount of neurons can cause a chain reaction across the brain, stopping activity in neurons that were uninjured.
These unaffected cells were labeled as ‘bystander’ cells by the researchers and their lack of activity post-injury may help explain a decline in cognitive functions.
Fruit flies are known for having similar neural networks to humans, with the team at Oregon University examining the bug’s axons. These are a threadline portion of a nerve cell that transmits signals within the nervous system.
Once a small portion of the axons were snipped the effects rippled around the creatures brain, causing a loss of neural signals in cells that remained unaltered.
“Even the so-called bystander neurons that aren’t injured or diseased can sense there’s been an injury and radically change their function,” said senior author Marc Freeman, director of the Vollum Institute at OHSU.
“That means that it’s not just the broken neurons that are affected when you have a nervous system injury – it’s maybe all of the neurons.”
The study attributed this reaction to the brain’s glial cells, which support and protect neurons.
“Glial cells are the watchdogs of nervous system health,” Freeman said. “Our work suggests that even when there’s a relatively small injury to some neurons, they can run out like Paul Revere and shut everything down.”
The group is unsure why this reaction happens, but they theories that this is the brain’s attempt to save energy.
After the injury, it is through the glial cells shutdown these neurons and once they realise they are uninjured they are effectively revived.
Freeman commented on this, saying: “Our best guess is that it allows the nervous system to pause after an injury. It enables cells to assess their status and, if they’re not healthy, activate programs to destroy themselves. If they’re healthy, they recover.”
