American physiologists have put forward a new hypothesis about the purpose of dreams: according to their version, vivid images stimulate the neurons of the visual cortex, protecting it from rapid "restructuring" to perform other functions.
Despite millennia of speculation and discussion, scientists still don't know exactly why we dream. According to various assumptions, they can serve, for example, to consolidate past experiences, prepare the brain to experience stress, or even to erase unnecessary memories. And recently, David Eagleman of Stanford University and Don Vaughn of the University of California, Los Angeles came up with a new and highly original idea.
According to them, the key detail of dreams is the very fact of the excitation of neurons in the visual cortex, thanks to which we see vivid pictures and scenes. Stimulation of these cells preserves the integrity of the connections between them, protecting the visual cortex from rapid degradation in the absence of external stimuli. Egelman and Vogue presented their “theory of defensive activation” in an article presented in the open online preprint library bioRxiv.
Let's remember that the human brain is highly plastic. The connections between his neurons are constantly renewed, removed and replaced. If some parts of the brain are not used for their usual purpose, they can be "reflashed" for other tasks: a striking example of this is what happens in the occipital lobe of some blind people, which, over time, can "switch" to tactile information from processing visual information.
According to a new assumption, even a break of several hours for the visual cortex can be dangerous. Deprived of external stimuli during sleep, her neurons can begin to be "captured" by other signals, so dreams protect them, taking additional "work".
But while this idea certainly deserves attention, it is not easy to agree with it. If only because for this neuroplasticity must develop extremely quickly, massively changing neural connections on the scale of hours, and not days and months. Such rates will have to be proved separately before considering the theories arising from them.