https://www.discovermagazine.com/mind/a-...f-dreaming
EXCERPTS: Why do we dream? [...] there is still no accepted answer. Now, David M. Eagleman and Don A. Vaughn have proposed a new theory. Their preprint article, which has not yet been peer reviewed, is called The Defensive Activation theory: dreaming as a mechanism to prevent takeover of the visual cortex. To my mind, it's a highly original and creative theory, but I'm not convinced by it.
Here's Eagleman and Vaughn's theory in nutshell: the role of dreams is to ensure that the brain's visual cortex is stimulated during sleep. Otherwise, if the visual system were deprived of input all night long, the visual cortex's function might degrade. [...] If we are in a dark place, or it's night, we get little or no visual input. So - in theory - our visual cortex would be vulnerable to 'takeover' by other senses, every single night. Dreams, on this view, are our brain's way of defending the integrity of our visual system by keeping it active.
[...] Eagleman and Vaughn's theory only makes sense if neuroplastic repurposing of the cortex happens very quickly. For the visual cortex to need defending, harmful neuroplasticity would need to occur in the space of a few hours. The authors do discuss evidence that rapid neuroplasticity can occur, but they don't show any evidence that these rapid changes are strong enough to be harmful. In fact, Eagleman and Vaughn don't really discuss any direct evidence for the dreams-as-defense... (MORE - details)
EXCERPTS: Why do we dream? [...] there is still no accepted answer. Now, David M. Eagleman and Don A. Vaughn have proposed a new theory. Their preprint article, which has not yet been peer reviewed, is called The Defensive Activation theory: dreaming as a mechanism to prevent takeover of the visual cortex. To my mind, it's a highly original and creative theory, but I'm not convinced by it.
Here's Eagleman and Vaughn's theory in nutshell: the role of dreams is to ensure that the brain's visual cortex is stimulated during sleep. Otherwise, if the visual system were deprived of input all night long, the visual cortex's function might degrade. [...] If we are in a dark place, or it's night, we get little or no visual input. So - in theory - our visual cortex would be vulnerable to 'takeover' by other senses, every single night. Dreams, on this view, are our brain's way of defending the integrity of our visual system by keeping it active.
[...] Eagleman and Vaughn's theory only makes sense if neuroplastic repurposing of the cortex happens very quickly. For the visual cortex to need defending, harmful neuroplasticity would need to occur in the space of a few hours. The authors do discuss evidence that rapid neuroplasticity can occur, but they don't show any evidence that these rapid changes are strong enough to be harmful. In fact, Eagleman and Vaughn don't really discuss any direct evidence for the dreams-as-defense... (MORE - details)