Maybe you've heard of the sleep disorder, narcolepsy? There's a famous video of a poodle with narcolepsy. You can watch it and see if it's similar to your dog.
Stanford Researchers Nab Gene For Narcolepsy in Dogs
The most dramatic symptom, however, is sudden episodes of muscle weakness known as cataplexy. The knees may buckle, the neck muscles may go slack, and in extreme cases the person may collapse to the floor completely paralyzed. Loss of muscle tone can last from a few seconds to several minutes. These abrupt attacks can occur at any time but are often triggered by strong emotions such as anger, joy or surprise. It's common for narcoleptics to have such an attack while laughing.
Sporadic cases of narcolepsy in dogs is due to hypocretin peptide deficiency while the familial form is due to mutations in one of the two hypocretin receptor genes (hcrtr2). Various dogs are shown here in a clip narrated by Dr. Mignot.
Seizures, Narcolepsy and REM
Narcolepsy is a disorder characterized by cataplexy, excessive sleepiness, and an abnormality in the phase of sleep called rapid eye movement (REM) sleep. In dogs, the most obvious sign is recurring cataleptic attacks. During a cataplectic attack, the dog suddenly collapses with paralysis of all muscles except for muscles that move the eyes and muscles responsible for breathing. The attacks are often provoked by excitement, such as feeding or play. They usually last only a few seconds, although severe episodes can last for several minutes.
During a cataplectic attack, the dog is usually conscious but unable to move. During a cataplectic attack the dog may enter REM sleep. Calling to the dog or touching the dog may terminate an attack.
I hope this helps you to solve your problem or rule it out. Good luck.
I agree with Dave. If Toto is collapsing and not moving and then getting up after one minute, it might be narcolepsy. Go to YouTube and do a search for “Narcoleptic Dog” and see if this similar to what Toto does. Good luck!