In Time magazine, two neuroscientists at Stanford and UCLA talked about the new theory. She explains exactly how dreams protect our brains.
In the past, neuroscientists were convinced that different parts of the brain were designed for specific functions. But recent discoveries have reversed the old paradigm. It was originally thought that one part of the brain was “assigned” one specific task; for example, the back of the brain is called the “visual cortex” because it usually controls vision. However, this area can be “reassigned” to another body function. There is nothing special about the neurons in the visual cortex: they are just neurons that are involved in processing shapes or colors in people with functioning eyes. But in the blind, the same neurons can be rearranged to process other types of information.
In the relentless competition for brain territory, the visual system faces a unique challenge: the rotation of the planet plunges humans into darkness for an average of 12 hours out of 24 (of course, this applies to the vast majority of evolutionary time, and not to the current electrified world). Our ancestors were in fact unwitting participants in the experiment, blindfolded every night.
So how did the visual cortex of the brain of our ancestors protect its “territory” from “readjustment” in the absence of information from the eyes?
Scientists asked this question and suggested in a new theory that the brain supports the activity of the visual cortex at night by dreaming. In the “theory of defensive activation” dreams in a dream exist precisely in order to maintain the activity of neurons in the visual cortex, thereby fighting the seizure of a part of the brain from neighboring sensory organs. From this point of view, dreams are primarily visual precisely because they are the only feeling that is at a disadvantage due to darkness. Only the visual cortex is so vulnerable, so its activity allows you to maintain its “territory”.
REM sleep is triggered by a special set of neurons that pump activity directly into the visual cortex of the brain, making a person’s vision “work” even with closed eyes. Sleep within sleep has a biological meaning and exists at least in part to prevent other senses from taking over the visual cortex of the brain when not in use. Dreams are a counterbalance to being flexible, scientists conclude.