The brain protein which has a hand, when defective, in the lethal disease CJD may also be involved in aiding our sense of smell.

Mice bred to lack the prion protein could not find buried food or choose between smells.

Columbia University scientists said some symptoms of prion disease might be due to the loss of the protein's original role.

The study was published in the journal Nature Neuroscience.

The prion protein has historically received something of a bad press, being blamed in its misshapen form for degenerative brain diseases in humans and other animals.

However, many scientists have been trying to uncover what it actually does when it is behaving correctly.

Dr Stuart Firestein's team believe that one of these roles is to help us smell.