Injury or disease that afflicts a relatively small number of brain cells causes a chain reaction that stops activity across a vast network of neural circuits, according to new research from Oregon Health & Science University.

The findings, published today in the journal Neuron, may help to explain why people can suffer from temporary but severe loss of cognitive function in cases of traumatic brain injury or disease.

“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, Ph.D., 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.”