Dog Dream
Do Dogs have Nightmare

Sleep is not uniform and is interrupted by small intervals that vary in intensity and profoundness. Two types of sleep have been distinguished; one is active and one passive. Here is an analysis of dog dreams and tries to explain if dog do have nightmare during those dreams.The previous stages before profound sleep could be classified as,
1^st the vigil state, with cortical and fast sub cortical activity during which the organism is in an attentive state. 
 2^nd state is slow sleep, where the respiration of the organism regulates. The heart becomes calmer than in the vigil state.
3^rd stage is profound sleep, where the waves are slower and the cortical and sub cortical activity varies in intensity.
During this last stage you can observe how a dog moves his eyes, contracts his upper lip, has spasms on his legs, grunts, softly barks, and the muscles on his neck will be completely relaxed. This type of sleep can be denominated as paradox sleep because it is accompanied by the certain movements which are someone intense and that occur every so often. This type of behavior has lead people to question if dogs dream.  A lot of people are under the impression that dogs dream because of the way they move while in their sleep and scientists are not completely sure about it. The question here would be if dogs have visions and do they see images inside of their dreams or is that the brain cells only transmit a message to their brains without the pictures or visions. Do dogs participate in their dreams?