Staying Balanced: Wake, Non-REM, and REM Life Phases
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Sleep researchers now propose that REM (rapid eye movement) dream sleep and NONREM sleep, along with waking consciousness, are all basic life phases that interface and depend upon one another. Each of these 3 life phases is as necessary as food and water. Animals prevented from having NONREM sleep or REM sleep will sicken and die. It is generally thought that NONREM takes on the more restorative processes and early new memory sorting, while REM seems to proceed from NONREM memory coding to the final stage of memory integration. Neuroimaging delineates Interactions between the hippocampal stored short-term memories, saved from the waking day, and the cortex occurring in both NONREM and REM sleep. This fascinating process facilitates learning and new memory integration into existing memory.

RESTORATION AND DEVELOPMENT

Sleep is a restorative experience, especially NONREM sleep. Importantly, it replenishes metabolic energy for the brain and generates cell replacement, for example immune cells, blood cells, and bone cells. NONREM sleep is necessary for brain waste removal. The brain uses more energy than any other part of the body; it is only about 2% of the body mass but uses about 22% of our energy. An especially energy-guzzling system is accessed during complex thinking and focus, which is why the brain’s motor circuits will take on repetitive tasks, automatizing them so that there is no longer a need for conscious focus. Once we learn the way to the grocery, we no longer have to concentrate on the route there. Because of this high energy utilization, the brain must remove the waste metabolic byproducts of the cells firing. This waste removal happens through the vascular/lymphatic system during NONREM deep sleep. This waste is primarily made up of amyloid, a substance known to promote dementia.

Relative to other primates, humans have shorter sleep periods but a significantly higher proportion of REM sleep. It is believed that REM sleep particularly enhances brain development, neuronal growth, and plasticity. Interestingly, infants in late uterine growth stages, and during the first few weeks of life, spend 90% of their sleep time in REM sleep. REM sleep decreases with growth but remains proportionately high in early life and again in adolescence. We know that children “borrow” their parents’ complex assessment centers. Caretakers meet the young child’s needs and help with a sense of identity development and emotional regulation. The prefrontal cortex, a primary circuit for discernment, emotional management, and decision-making, is the last part of brain development and is intimately impacted by REM sleep.

A primary function of REM dream sleep is to further integrate the now NONREM partially processed newly learned information into existing memory. This is accomplished in an almost playful, random trial and error manner. New memories are paired in REM sleep often with divergent associations in existing memory. Remote associations of dream sleep are thought to potentially promote survival value by generating novel and creative ideas for problem solving and adaptation.The complex circuits of logical thinking are offline during REM sleep as are peripheral muscle connections, and perceptual sensation. One is essentially paralyzed in REM sleep. A reconnection of circuits that have been previously disconnected during the earlier night are restored in late REM sleep. Interestingly pathways activated during sleep phases appear to be primarily the default mode networks of self-awareness and social attachment.

Adequate amounts of REM sleep, which unlike deep sleep does not seem to decline with aging, are associated with longevity. In contrast, chronically reduced REM sleep may presage mortality. REM sleep remains fairly stable in adulthood, but deep NONREM sleep shows a remarkable decline in late life.Thermal regulation, a very precise window of temperature range that must be maintained for life, is calibrated in REM sleep.

STAYING QUIET AND REFLECTIVE

Some researchers consider feelings to be an extension of homeostasis-a steady balanced supply of life needs necessary for all life forms. From this perspective, feelings are signals for survival needs. Dysregulation, physical or emotional, is a threat to survival. Feeling signals are sent from the sensory circuits like the eyes, ears, or touch. They first reach the lower brain survival and motivational circuitry. If the signal does not indicate a threat, it is forward on to interface with the mentoring systems of complex assessment, perhaps portending good decision-making with homeostasis maintained. If the perception is one of threat, then the signal is reacted upon with little or no complex scrutiny by higher brain centers.

Getting adequate NONREM and REM sleep promotes cortical control and emotional regulation. REM sleep is the body’s most focused effort towards reducing intensified feeling signals that have to do with threat perception and fear. It is now understood that REM sleep assimilates distressing experiences and emotions in the absence of the adrenal activation system. REM is thought to be inhibited by adrenal system arousal and particularly by norepinephrine which primarily increases focus, vigilance, heart rate, and blood pressure. Instead, REM sleep is dominated by the cholinergic system and is one of the body’s natural ways to integrate and quiet fearful experiences. Humanity has always faced threats and needed to manage anxiety and loss so as to maintain homeostasis and viability. This REM function of reducing anxiety is of seminal importance to our capacity to self-regulate negative emotions which disrupt body states of homeostasis.

People who experience dreams related to traumatic events are more able to return to an emotionally calibrated waking state. Recurrent trauma-related dreams and nightmares, however, are now thought to represent a breakdown in REM sleep integration of new and old memories. REM sleep memory consolidation and emotional equilibration function can be prevented by elevated adrenal (fear) activation chemistry. It is believed that unprocessed trauma memory in these cases remains in the hippocampal short-term memory center and gets easily reactivated to trauma-related cues.

People who have experienced trauma and profound loss often say that their sense of themselves and their life story has been forever changed. Recent research indicates that exposure therapy is quite successful in integrating certain kinds of traumatic experiences.This trauma-related therapy is done in a safe environment and facilitated by a relaxed body state. So speaking with someone trusted in a relaxed state about traumatic events can, like REM sleep, help to incorporate distress into quiet acceptance and a more coherent life story.

FAVORING UNMEDICATED SLEEP

Ironically, our past efforts to regulate emotional states and to induce sleep have sometimes impeded the sleeping body’s natural ability for quiet restoration. It is important for health care providers to realize that antidepressants, especially the older tricyclic antidepressants, long-acting antidepressants, alcohol, and benzodiazepines remarkably reduce REM sleep. Restorative sleep is set up by even daytime routines and thinking, emotional quieting, exercise, light/dark, and careful avoidance of sleep impairing substances. Alcohol will often induce a drowsy sleep sensation, but it initiates activation rebound resulting in awakening 3 to 4 hours later. There are also micro-awakenings, out of conscious awareness, during rest with alcohol use. Caffeine lasts about 12 hours in the body. Even if it doesn’t keep you awake, it may result in a 40 to 70% decrease in deep sleep.

Many antidepressant and attention deficit medications impede both REM and NONREM sleep. In fact sleep investigators use antidepressant medications in research animals to decrease or eliminate REM sleep. There was a time when we were told to take an antidepressant in the morning or at night. Now sleep researchers are saying to only use morning dosing and to avoid long-acting antidepressants as they interfere with sleep cycling restoration. Dopaminergic agents degrade deep sleep. Norepinephrine is almost completely quiescent during REM sleep.

Medicated sleep that impedes REM or NONREM sleep is not necessarily restorative. Just because someone has been unconscious 8 hours does not mean that it has been restorative sleep, the evolutionary purpose of sleep. Researchers are recently making a delineation between sleep and sedation. Sleep is an active cyclic process that is depicted with imaging to entail communication across brain circuits. Sedation generally inhibits the brain’s circuits from communicating with one another. This interactive system communication is a core element of memory consolidation.

KNOWLEDGE IS POWER

Understanding Wake, NONREM, AND REM as sequentially interfacing life phases may increase awareness of their intricate interplay promoting survival and well-being. This awareness may lead to more careful daily habits of living to enhance each phase so as to optimize sleep restoration, emotional, and physical health.

- Dr. Linda Klaitz, Medical Psychologist

   

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