The Role of Nighttime Hallucinations in Neuroscience

The brain is always sprung tight like a mouse trap to implement rapid change. The reorganization of territory that brains do, it's not like the glacial drifting of continental plates, but it can be remarkably fast. And this is one of the unsolved mysteries in neuroscience is why brains dream what these bizarre nighttime hallucinations are about. Do they have meaning? Are they simply random neural activity in search of a coherent narrative? And why are dreams so richly visual igniting the occipital cortex every night in this conflagration of activity?