BACE1 and Bilateral tonic-clonic seizure: Interestingly, all of the generalized tonic-clonic seizures in BACE1-/- mice began during non-REM sleep, and were characterized by an abrupt loss of muscle tone (atonia) lasting 2-3 seconds (additional file 2: Video 2), followed immediately by tonic-clonic convulsions lasting from 1-4 minutes.