In April 2017, a group of scientists from the University of Wisconsin-Madison identified a “posterior cortical hot zone” in the brain that could indicate whether a person was dreaming (having a subjective experience) or not… “When we wake someone up, and they report hearing something, or there was speech for example, we find activation in a very specific part of the cortex: the Wernick’s area, which is known for processing speech,” says Benjamin Baird, a lead scientist on the study.