We All Dream

Every night you go insane. You enter a world where the laws of physics do not apply. Where the dead are alive. Where you can fly but cannot run. Where buildings rearrange themselves as you walk through them. Where time collapses and expands without warning. and where the most bizarre, the most terrifying, and the most profoundly beautiful experiences unfold with a vividness and an emotional intensity that often exceeds anything you experience while awake. You inhabit this world for approximately 2 hours every night. You have spent approximately 6 years of your life in it. And when you wake, the world dissolves, leaving behind fragments, traces, and the lingering sense that something important happened that you cannot quite remember. Dreams are the most universal, the most frequent, and the most poorly understood altered state of consciousness that human beings experience.

Every person dreams, every mammal dreams, every bird dreams. And the dreams are not random noise, not the meaningless byproduct of a brain running maintenance routines during sleep. The dreams are structured. They are narratively coherent. They contain characters, settings, plots, and emotional arcs that unfold with a logic that is different from waking logic, but that is in its own domain remarkably consistent. The dreams are doing something. The question is what? The neuroscience of dreaming has made extraordinary progress in the past three decades, but the progress has deepened the mystery rather than resolving it. We now know more about when dreams occur, which brain regions are active during dreams, and what neurochemical conditions produce the dream state. But we know almost nothing about why dreams have the specific content they have, why you dream about a specific person on a specific night, why the dream contains specific details that you did not consciously think about during the day, and why the dream sometimes contains information that you did not have access to through any normal channel. The when is well established. Dreams occur primarily during rapid eye movement, sleep, REM sleep, the phase of sleep characterized by fast, irregular eye movements beneath closed lids, by the near complete paralysis of the voluntary muscles, by brain activity patterns that closely resemble waking consciousness, and by the vivid, bizarre, emotionally intense experiences that subjects report when awakened from REM. REM sleep occurs in cycles of approximately 90 minutes with each cycle producing a longer REM period. The first REM period of the night lasts approximately 10 minutes. The last may last 45 minutes or more. And the total REM time per night is approximately 90 to 120 minutes. 2 hours of dreaming per night every night for the duration of your life. The brain activity during REM is extraordinary.

The visual cortex is active, as active as during waking visual perception, producing the vivid visual imagery that characterizes most dreams. The motor cortex is active, generating the motor commands that would produce the movements the dreamer experiences, but that are blocked by the atonia, the muscle paralysis that REM sleep imposes to prevent the dreamer from acting out the dream. The limbic system is hyperactive. The amygdala, the emotional processing center, is more active during REM than during any waking state, producing the intense emotions, fear, joy, desire, grief, awe that dreams carry. And the prefrontal cortex is hypoactive, the region responsible for logical reasoning, critical judgment, and the sense of self is suppressed during REM. Which is why dreams feel real while they are happening. Why the dreamer does not question the bizarre events unfolding around them and why the critical faculty that would immediately flag a flying elephant or a talking river as impossible in waking life is absent during the dream. The pattern of brain activity during REM poses a paradox that the neuroscience has not resolved. The sensory input regions of the brain are active but the senses are shut off. The motor output regions are active but the muscles are paralyzed. The emotional processing regions are hyperactive but there is no external emotional stimulus and the visual cortex is generating detailed vivid cinematically rich visual experiences but the eyes are closed and no light is entering the retina. The dreaming brain is behaving as though it is perceiving an external world but the external world has been disconnected. The brain is generating the complete experience of a reality that does not exist in the physical environment. It is generating the experience from an internal source. What is the internal source? The standard neuroscientific answer is that the source is memory. that the brain recombines stored memories, reconfigures familiar elements, and generates the dream experience from the raw material of past experience. This answer is partially correct. Dreams do contain elements of past experience, familiar faces, familiar places, familiar situations recombined into new configurations. But the answer is incomplete because dreams also contain elements that are not from past experience. Elements that the dreamer has never encountered. Details that the dreamer could not have stored in memory and information that the dreamer could not have acquired through any normal channel. 

The neurochemistry of REM is equally distinctive. The neuron modulators that dominate waking consciousness, norepinephrine, serotonin, and histamine are suppressed during REM. The neuron modulator that dominates REM is acetylcholine which floods the brain at levels that exceed waking levels and that produces the characteristic features of the dream state. the vivid sensory imagery, the emotional intensity, the associative, nonlinear, symbolically rich cognitive processing that dreams display. The suppression of norepinephrine is particularly significant. Norepinephrine is the neurochemical of focused attention, logical sequencing, and reality testing. Its suppression during REM removes the cognitive framework that the waking mind uses to distinguish real events from imagined ones. Which is why the dream feels real while it is happening and why the dreamer cannot tell from within the dream that the experience is not waking reality. The suppression of the reality testing neurotransmitters during REM has a specific implication that the neuroscience has not fully explored. The dreaming brain is in a state of reduced decoherence.

Decoherence, the process by which the quantum superpositions of the brain's microtubules are collapsed by the thermal interactions with the environment is mediated in part by the noradrenergic and serotonergic systems that are suppressed during REM. The suppression of these systems during REM reduces the decoherence rate, allowing the microtubules quantum superpositions to persist for longer periods and to achieve a degree of coherence that the waking brain with its full complement of decoherence inducing neurotransmitters cannot sustain. If the Orch OR model is correct, if consciousness is produced by quantum processes in the microtubules, then the dreaming brain's reduced decoherence means that the dreaming consciousness has access to deeper quantum information than the waking consciousness. The quantum computations in the microtubules can explore a wider range of quantum states, access more of the plank scale information, and perceive more of the temporal and spatial information that the entanglement structure of the block universe encodes. The dreaming brain is in the Orch OR framework a quantum receiver with a wider bandwidth. A receiver that can detect signals that the waking brain's higher decoherence rate filters out. This has a specific testable prediction. The anomalous information in dreams, the information that the dreamer could not have obtained through normal channels, should be more abundant during the deepest REM periods. When the norepinephrine suppression is most complete and the decoherence rate is at its lowest, the prediction has not been tested.

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