Rapid eye movements during sleep help us better understand dreamland

A recent study may broaden our understanding about what happens when we sleep, specifically in regard to our eye movements during dreams.

Published in Nature Communications, the data suggests that the eye movements of a dreaming person and the activity deep in the brain, may reflect the movements of the eyes and the processing for the visual information of the person in their dream.

Simply put, our eye movements when we dream seem to follow the same pattern as when we are awake. This idea that our mind scans the dream image has existed, but the study’s co-author Yuval Nir says, “It’s been very difficult to prove it.”

In order to draw this conclusion, researchers monitored different brain activity in different settings (awake and asleep), analyzed it and compared brain activity of these patients when they were awake. The researchers had a unique patient population with implanted electrodes, for their uncontrolled chronic epilepsy, and monitored the activity

“This type of meticulous study is important to continue in our understanding of the brain and how it works but may be too novel and too much observational to make much impact in our clinical treatment of the patient with a sleep disorder,” says Patricia Ritch MD, PhD.

Dr. Ritch is the medical director of the Hillcrest Sleep Center in Waco and has extensive studies in both neurology and sleep medicine. She is interested in these findings, although she says they are very “basic science,” rather than “clinical science,” and further research is needed.

What happens when we dream

Experts agree that sleep is essential to life. We experience Light Sleep, Deep Sleep and Dream Sleep, each stage has different roles. Researchers in this study were analyzing the Dream Sleep, also called REM Sleep.

“During this stage, we imagine that the brain is updating everything that makes us who we are. Every memory, every skill, every thing we have read, watched, and experienced must be updated and saved,” says Dr. Ritch. “It is similar to when a computer saves its information.”

Also during Dream Sleep our body becomes relaxed and the only muscles that work are those that control the eyes, the heart and the diaphragm. Dr. Ritch says we know the eye muscles work because we can detect movements called Rapid Eye Movements (REMs) only during this stage of sleep.

“When a person is awakened during the Dream Sleep stage they will recall vivid dreams so there has always been a suspicion that the movements of the eyes are related to the things a person was seeing in their dream,” says Dr. Ritch. “This study tries to obtain data to support the fact that REMs during sleep are similar to the movements of the eyes during wakefulness when the visual image is being processed.”

Monitoring brain activity during dreams

So do our eyes really follow the same movements whether we are dreaming or awake? Although many assumed so, this group set out to prove it by listening to the brain.

The study involved patients with chronic epilepsy, having the electrodes implanted into areas of the brain involved with epilepsy. This gave them a unique source of information, as the EEG can help detect very distinct patterns of the brain, based on the charges in the electrical signal.

“The way the EEG signal looked when the subjects were asleep in REM sleep was compared to how the EEG looked when they were awake but having REM associated with visual stimulation,” says Dr. Ritch.

The discussion points out that there are several other possibilities for the same results but the novel data “may imply that REMs during sleep reflect a change of the visual imagery in dreams.”

Importance moving forward

This is a step in the right direction, but the observational study does not give us all of the information we need in order to make a significant impact for treatment.

“Clinically speaking, it may be important to understand what goes on in all stages of sleep to improve our ability to help correct disorders that could affect them,” says Dr. Ritch.

There are a number of disorders associated with sleep, like PTSD patients dreaming of traumatic experiences, or REM behavior disorder patients acting out violently during sleep. Sleep research that helps the medical community may also aid in managing medications to determine if it impacts REM sleep.

Thanks to these findings, we have a little more understanding about what exactly goes on in dreamland.