Is my dog dreaming?
Unless you can converse with your dog and be able to ask him the question, we will never know for sure what is going on in his mind when he fidgets while sleeping.
What we do know, however, is that the structure of the dog's brain is very similar to that of humans and that their functioning is therefore very similar during sleep. Like humans, a dog's sleep is made up of a succession of cycles. Each of these cycles is broken down into 5 phases: falling asleep, light sleep, slow sleep, deep sleep and paradoxical sleep.
It is during REM sleep that the electroencephalogram shows the greatest activity even when muscle tone is at its lowest. During this phase, the dog - like the human being - is only able to move its eyes under closed eyelids. We then speak of MOR phases for Rapid Eye Movements or REM in English for Rapid Eye Movement.
It is these eye movements that are characteristic of the dream phase in humans and it is precisely during this phase that dogs are most restless in their sleep. We can therefore reasonably assume that they too are dreaming during this time.
What do dogs dream about?
There again, it is difficult to be certain on the issue. We can only speculate as to the nature of the dreams of our dear domestic canines.
Some scientific experiments carried out on cats can nevertheless shed some light on the matter.They consisted of lifting the blocking of movements that normally occurs in the paradoxical sleep phase by brain surgery. During the REM sleep of operated cats, we were able to observe exploration, grooming or watchful behaviors very similar to those observed when the animal is awake. Emotional reactions similar to fear and anger have also been observed.
As with cats, it is therefore very likely that dogs dream of what usually happens in their day. What we do not know and will probably never know is whether the dog dreams in images, colors or smells, nor the stories he lives in dreams.
Can you wake up your dog when he is restless in his sleep?

During his REM sleep phase, it is therefore not uncommon to witness high-pitched barking, pedaling of the paws, twitches and even eye movements if the eyelids are half-open.Some dogs can even start to howl so much that you can ask yourself the question of whether to wake your dog to reassure him when this happens.
In reality, waking up your pet while he's dreaming or having a nightmare doesn't seem like a good idea.
While the function of REM sleep and dreams is not currently known and this, it is nevertheless assumed that it could serve to promote the long-term storage of information in memory, therefore playing a preponderant role in learning. Animal experiments have shown that those who were interrupted had more difficulty reproducing a task learned the day before, compared to those who slept without interruption.
More generally, we know that interrupted sleep can impact the well-being of the animal by causing many emotional disorders, including irritability!
So if your dog seems restless while sleeping, know that it's completely normal and nothing to worry about. It is therefore best not to interrupt your sleep when this happens.