Just a small number of damaged brain cells can cause the whole brain to shut down after a traumatic brain injury, a major study has revealed.
The research, published by the Oregon Health & Science University, is among the first to highlight a “chain reaction” effect resulting from a blow to the head.
While it is well known that a traumatic brain injury can cause patients to suffer “temporary” but “severe loss” of cognitive function, very little was known as to why it happens.
Until now, that is.
To carry out the study, traumatic brain injuries were recreated in fruit flies, which were then studied to see how the brain cells reacted in the hours after injury.
It was found that injury or disease that afflicts a relatively small number of brain cells caused a chain reaction that stops activity “across a vast network of neural circuits”.
It means that even healthy brain cells that were not damaged were suppressed, causing a loss in cognitive and sensory function.
Commenting on the study, senior author Marc Freeman said: “Even the so-called bystander neurons that aren’t injured or diseased can sense there’s been an injury and radically change their function.
“A small injury can cause the whole nerve to shut down.”
He added: “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.”
According to the latest statistics, there were 348,000 admissions to UK hospitals with an acquired brain injury in 2016-17 – the latest data available.