Scientists can tell when someone is dreaming by their EEG

[Sandy Lomax]

https://www.theguardian.com/science/2017/apr/10/scientists-identify-parts-of-brain-involved-in-dreaming

This article in the Guardian says that scientists at the University of Wisconsin-Madison have recorded 46 people`s EEG while they were sleeping. They found that people dream during both REM and non-REM sleep. (REM means Rapid-Eye-Movement). The area at the back of the brain, involving vision and integration of the senses, had high frequency patterns during dreaming. People`s recall of dreams was linked with an area in the front of the brain. Other links to facial recognition, space perception, and movement were also identified.