Burrowing into prion disease

Mice received intra-hippocampal injections of scrapie-infected brain homoge nate. Open field activity increased from around week 12 post-injection. Con comitantly the tendency to displace food from a tube inside the home cage d ecreased. The food was generally dug out with the feet, rather than carried by mouth, so its displacement was called burrowing. Food restriction was u nnecessary for this burrowing to occur. Only later, around 18 weeks, did mo re general motor impairments develop. As burrowing in scrapie-infected mice decreased when open field activity increased, and preceded later motor imp airments, it was not due to motor dysfunction. Burrowing is a simple, sensi tive, objective, ethological measure, sensitive to preclinical prion diseas e. Other potential applications are in transgenic and knockout mice, models of ageing and Alzheimer's disease, and pharmacology, particularly neurolep tics. NeuroReport 12:2053-2057 (C) 2001 Lippincott Williams & Wilkins.