e all are acquainted with Rapid Eye movement (REM) sleep. It’s the phase in our sleep cycle that’s characterised by the movement of our eyes, and through which dreams occur. But, till now, why this eye movement happens was largely a mystery. As a part of a recent study, scientists have found a reason behind this eye movement.

An experiment was conducted on mice by researchers from the University of California, during which the brains of sleeping rodents were observed and conclusions were derived.

The outcomes gave a transparent answer. It sided with the scanning theory hypothesis, which assumes that in REM sleep the eyes occur to be keeping track of the virtual scenery of their dreamland.

The speculation might sound reasonable, but is difficult to support experimentally. Previous studies on humans have relied on woke up sleepers self-reporting their dreams, which researchers in comparison with their eye movements. Nonetheless, this approach is just not rock-solid and leaves room for doubt.

Furthermore, not all studies discover a correlation between rapid eye movements and dream imagery.

To bypass the difficulties of studying the rapid movement of our eyeballs beneath their lids — termed as saccades — in humans, the researchers used mice as an alternative.

Particularly, they measured the neural activity within the mouse thalamus that’s accountable for pointing the top in a specific direction. This was achieved by implanting small probes, while allowing them to freely explore their environments in an awake state. Concurrently, a series of cameras captured every movement of their eyes.

In awake mice, saccades are inclined to align with head movements as mice travel the actual world.

When the test subjects took a nap, the sensors kept on recording. Baselines in neural activity and saccades found throughout the waking phases were then used to match the likelihood of the attention movements during REM being related to their intended direction through their virtual world.

The outcomes provided objective evidence of a link between the mouse’s rapid eye movements and the brain’s control over head movements, and were published within the journal Science.

It’s essentially the most direct evidence for the scanning hypothesis one can get without replicating similar measures on a human brain – an invasive procedure that is just not entirely unheard of before.

ScienceAlert reported that “in keeping with a commentary by neurologists Cathrin Canto and Chris De Zeeuw from the Netherlands Institute for Neuroscience, reading the attention movements during sleep could help inform therapies for improving memory or managing trauma.”

“Muscle twitches, which also incessantly occur during REM sleep, may be related to the inner heading cues provided by rapid eye movements, and analyses of those might give further details about dreams,” Canto and Zeeuw wrote in a statement.