nervous twitch

Question
MY HEALTHY 10 MO. OLD RAT TERRIER SOMETIMES SHAKES WHEN HE IS SLEEPING.IT APPEARS TO BE A NERVOUS TWITCH HE HAS HAD ALL HIS LIFE.IT ONLY HAPPENS WHEN HE IS LAYING DOWN RESTING OR SLEEPING.IS THIS NORMAL BEHAVIOR? THANKS CRAIG

Answer
If this "shaking" is brief and associated with REM (watch his eyelids) he is dreaming.  If it is prolonged (more than five minutes) take this behavior to the veterinarian and ask for a full neurological evaluation.  if you know the dog is NOT asleep, this may be neurological and he will definitely need a veterinary evaluation.