Perspectives on Dreaming
"That you have but slumber'd here
While these visions did appear.
And this weak and idle theme,
No more yielding but a dream…."
William Shakespeare, A Midsummer Night's Dream
Each night, visions inhabit our minds during sleep and vanish with the morning light. These visions, these dreams, are without substance. Often, the waking mind recalls dreams only vaguely, if at all. A complete, separate world seems to exist within each of us; a world that can only be found through sleep, through dreams. What are dreams? Why do some people find nightly reverie in the comfort of their beds, while others dread sleep, terrified of the content of their dreams, and yet others recall no dreams to fear or fancy? Speculations on dreams are common and vastly variant. Some people imagine that their dreams are prophetic, while others insist that dreams are merely random firings of neurons. Perhaps a more encompassing view of dreams is appropriate. Neural firing causes dreams, but the randomness of dreams is questionable, since dreams are often correlated with the immediate emotional state of the dreamer. The theories that are presented here do not completely explain dreams. There are many missing pieces to the puzzle of the mind, and our theories on dreaming still have rather large holes.
Dreams occur during sleep. While REM sleep is the best biological condition for dreaming, dreams may occur any time during sleep (1). The brain is less responsive to external inputs while sleeping, engaged, instead, with internally generated input (2) . While responsiveness to external input is greatly reduced during sleep, the brain in not completely unresponsive and can be stimulated by the environment (1) . Thus, external influences can effect dreams. For example, alarm clocks and telephone noises can be incorporated into dreams, as can inputs originating in the body but outside the nervous system, such as the need to urinate. The extent that external activity modifies dreams is difficult to ascertain because the person is often awakened by such activity.
A possible purpose for sleep is that decreased responsiveness allows the brain to undergo "dynamic stabilization," or DS, which is essentially the activation of synapses in neural circuits of the cerebral cortex to enhance and maintain neural functioning (2) . Generally, DS does not initiate the activation of a neural circuit because of extensive inhibition of the motor neurons, and is therefore "non-utilitarian", meaning that there are no visible physical results (2) . DS can occur during consciousness, but the cerebral complexity of warm-blooded vertebrates requires more DS than can occur simultaneously with the processing necessary for waking thought and perception. Sleep thus evolved to provide the brain with a condition virtually free from external distraction (2) .
DS occurs most frequently during REM sleep (2) , which is also the state biologically most suitable for...