A new study on REM sleep reveals that changing scenes in dreams could correlate with changes in eye movement.

Scientists have been able to isolate and study individual brain cells for the first time during dream sleep. They found that with each rapid eye movement, changes in neurons also occurred.

The subjects had electrodes attached to their heads to monitor possible seizures. Over the course of the study, nineteen patients were observed, with a focus on their medial temporal lobes.

The neuron activity is not directly associated with image processing, but rather concepts. When shown specific images, neurons fire.

Dr. Yuval Nir of Tel Aviv University in Israel, says, "About a 0.3 seconds after the picture appears, these neurons burst - they become vigorously active. This also happens when people just close their eyes and imagine these pictures or these concepts."

This activity is very similar to what happens during dream sleep.

"We are intimately familiar with the activity of these neurons. We know they are active every time you look at an image, or when you imagine that image. And now we see them active in a similar way when you move your eyes in REM sleep, so it becomes very probable that the eye movements represent some type of reset or moving onto the next dream frame," says Nir.

Professor Jim Horne of the Sleep Research Centre at Loughborough University says the findings are consistent with current understandings of dream sleep, which has more similarities to wakefulness than previously thought.

"I see REM sleep as rather like the screensaver on your computer; all you need is the touch of a button and your computer leaps to life," he said. "It's very close to wakefulness. Non-REM sleep is more like when you switch your computer off, and waking up requires a process of rebooting."

Facts about dreaming:

 Most dreams last between five and twenty minutes.

 During a typical lifetime, people spend about six years dreaming.

 We've learned most of what we know about sleep in the past 25 years.

 Some researchers believe the themes of REM dreams are topics we want to remember or fix in our waking life, others think they are things we need to forget in order to think more clearly in wakefulness.