A recent University of Iowa study identifies a group of neurons responsible for arousal that are directly triggered by carbon dioxide and cause mice to wake up without any changes to breathing, reports The Daily Iowan.

“Arousal from sleep is important because it wakes the person up and restores tone to the airway, so it allows normal flow of air,” senior study author and Assistant Professor of neurology Gordon Buchanan said. “Without that, the person would remain obstructed and die.”

The study indicates that arousal from sleep in response to increased carbon dioxide can occur independent of breathing, research assistant and coauthor Callie Ginapp said in an email to The Daily Iowan. This is especially relevant in the case of  sudden infant death syndrome and sudden unexpected death in epilepsy, she said.