REGIONAL CEREBRAL BLOOD FLOW (RCBF RCBF): Regional cerebral blood flow monitoring may help boost the validity of the regional localization theory, in which specific parts of the brain control specific functions.. measure of the blood flow in a specific area of the brain, using positron emission tomography (PET scans) and/or single photon emission computed tomography.
If a dog goes on his back to you he is accepting you as his master. This is part of the answer but here's a little more in-depth version as reported by USA Today. In general, dogs lie on their back for three reasons.
If you are debating over whether it is time to put your dog to sleep remember to cherish every day and every moment with your dog, because those very last days will always be in your heart. When your dog's time comes, he or she will let you know it is time to cross the Rainbow Bridge in a leap of faith. Dogs unlike humans do not fear death because they live in the moment. Do not worry for your dog, he /she will be in a better place and best of all, will be eternally pain free.