Night terrors are very intense episodes of fear and screaming during sleep. They are usually found in children. You can learn more here: http://weird.answers.com/facts/night-terrors-a-frightening-sleep-mystery
They occur during REM sleep, usually in the second half of the night
Sleepwalking usually occurs during stages 3 and 4 of the NREM part of your sleep cycles. NREM means the non-rapid eye movement stage. REM means rapid eye movement. Night terrors aren't exactly well understood, but most professionals will agree that they happen during the NREM stages of your sleep cycles.
They occur during REM sleep, usually in the second half of the night
A nightmare is one of those dreams where, when you wake up, you thing "Oh, thank goodness. It was only a dream." Then you roll over and go back to sleep. Night terrors are dreams so vivid that you wake up thinking that the incident actually occurred, and may continue to think so until you are fully awake. Most people have them once or twice a year. If you are having night terrors regularly, you need to consult a professional and get some counseling. Frequent sleep disruptions are extremely bad for your physical and emotional health. Whatever you do, don't drink or take sleeping medications to avoid them. They do nothing to correct the underlying problem, and you will become dependent on the booze or meds to help you sleep, just adding another layer of problems.
stage 4
the physician may prescribe a benzodiazepine tranquilizer, such as Diazepam, known to suppress Stage 4 of sleep. The physician may also refer the affected person for further evaluation by a sleep disorder specialist
Most vivid dreams occur during REM sleep, which stands for Rapid Eye Movement. REM The vividness of dreams might depend more on whether one awakens directly from the dream or not, rather than the stage of sleep where dreams occur. Sleep studies have shown that REM (rapid eye movement) sleep correlates closely with dreaming, but dreams occur during other sleep stages as well. Night terrors, sleep walking and other disturbances tend to appear during deep or slow-wave sleep, Stage N3. See the attached Wikipedia article, below, for further information and resources. In REM sleep. REM-sleep. It stands for rapid eye movement, a characteristic of dreaming in which the eyes flutter side to side very quickly as the brain works. It happens during stage 5 of sleep.
It happens in the 4th stage
Sleep paralysis typically occurs during the stage of sleep known as REM (rapid eye movement) sleep.
The rhythmic bursts of brain activity that occur during Stage 2 sleep are called sleep spindles. These are short bursts of brain waves that help in the consolidation of memories and are characteristic of this stage of sleep.
sleep spindles
The small minority of people who do sometimes talk when asleep appear to do so during the NREM or non rapid eye movement phases of their night's total sleep, and do not appear to remember dreaming in connection with what they said.