An abnormality in the reflex that stops breathing when food 'goes down the wrong way' may be linked to cot death, scientists claim.
Researchers in Australia found two areas of the brain that work in tandem to control breathing and swallowing. If this goes awry, they believe it could cause Sudden Infant Death Syndrome (Sids).
The vocal cords are brought together by the reflex to trigger coughing and swallowing.
In babies it is especially important because they have a tendency to regurgitate liquids after feeding.
But it is also risky, because when breathing stops blood oxygen levels can drop to dangerously low levels.
Lead researcher Professor Paul Pilowsky, from Macquarie University in Sydney, said: "The closing of the airway in adults is only a small compromise as breathing is only stopped temporarily. But for babies the response has more radical implications, particularly if breathing stops for a long time, as they can't take in oxygen or get rid of carbon dioxide.
"The timing of breathing and swallowing is exquisitely co-ordinated. We suspect that co-ordination of the two may be going awry in Sids, but to be sure of this, we need to know how the brain organises this response in the first place."
Working with rats, the scientists used electrical stimulation to mimic the brain and body's response to a throat irritant.
By measuring neural activity linked to the reflex the team hopes to get a better understanding of what causes the brain to halt breathing for long periods.
The research has been published in the Journal of Physiology.