Conclusion

1.) How are they triggered, specifically?

The nightmares may occur in times of severe tension, or after watching something with some type of suspense or horror. They may also occur when you have an illness, or if you may have ate before bed. One last way they may show up is if you are having withdrawls from any acohol or drugs.

2.) Where do they come from?

This question wasn't exactly answered, I know they occur during REM sleep, but they don't exactly come from anywhere. Although, they are known to tell us things about ourselves. They may help us solve problems, or things in that matter. If you really think about your nightmare, I ganrantee you will find a way it helps or relates to something that has happened to you.

3.) Do you remember them all in the morning? Why or why not?

You do tend to remember them all in the morning, because most of the time you will wake up during them, and you will remember everything. As for dreams, you will not always remember them in the morning because you have so many dreams a night, that you can't remember them all in the morning. Same with night terrors, you most likely will never remember those, because they happen so quick, you may wake up screaming, but fall back to sleep with in a minute. This is because you are not totally waken yet, so technically you are still asleep, so you don't remember. This is why a lot of people keep a dream log next to their bed, so if they wake up during the night, or in the morning, as soon as they wake up, they will write down everything they remember. With night terrors, if someone is able to recall anything about it, it is usually just a frightening image, or something of that matter.

4.) Do they occur during REM?

REM is abriviated for "rapid eye movement" , this occurs in some of your deepest stages of sleep. Almost all of your nightmares occur during this time, you will find that night terrors for instance, do not, same with dreams. Some dreams may occur during REM sleep, but nightmares will almost always occur during this time.