The Science of Dreaming by Robert J. Hoss, MS Part #1 The Science of Dreaming Contents • Section 1 Sleep and Dreaming 1 • Section 2 The Neuroscience 14 • Section 3 Do Dreams Have a Function? 32 • Section 4 Dream Content 46 • References 77 Introduction It is exciting to think that dreams might have some “meaning” for us that can help us better understand and transform our lives. Although many of us have experienced the therapeutic value of dreams when applying solid dreamwork principles, there is still controversy over whether dreams are meaningful or even have a function. It would perhaps be a failure of understanding and imagination if we relegate dreams to the babble of a sleeping mind, simply because we are unable to understand the language of the dreaming brain. You will learn in this document that we dream every night, in stages all through the night and that much our brain remains active when we dream, including centers that process emotion, memory, imagery, association, analogical problem resolution and learning - all of which can be associated with our waking life situations and contributes to the inner modeling of our world view. If you are interested in understanding and working with your dreams, click on the Dreamwork or Psychology of Dreaming link on this site. There you will find a number of proven tools and approaches for group and individual dreamwork. Understanding the dream in relation to your life is only the very first step so this you will be introduced to tools for exploring the underlying emotional issues the dream is dealing with and how to recognize how the dream is attempting to find resolution and closure. Section 1- Sleep and Dreaming Sleep is by no means an inactive state for the nervous system – Ernest Hartmann What are Dreams? In the simplest terms a dream is the state of consciousness we achieve in the sleep state. Among researchers there is still come controversy over the definition of a dream; whether dreams are the vivid emotionally charged story-like dreams we generally recall when we wake, or can it be any form of mentation (thoughts, fleeting images, mental impressions) that are taking place as we sleep. For the most part dreams are generally accepted as any sort of visual or simply thought like activity that might be recalled when we wake from sleep. Researcher Bill Domhoff (2005) states that there are four conditions required for dreaming: 1) an intact fully mature neural network for dreaming; 2) a mechanism for activating the dream; 3) exclusion of external stimulus; and [aside from lucid dreaming], 4) loss of self-control or deactivation of the “cognitive system” 1 © Robert J. Hoss Early thought was that dreaming was primarily a REM sleep phenomenon. However, the dream or dreamlike state is now known to also occur during all states of sleep; at onset and during various stages of NREM and of course REM. Dream content differs between the stages and is reported to a lesser degree in NREM, as discussed below. When Do We Dream? Figure 1-1 illustrates the or common cycles of human sleep or “sleep architecture” that occurs every night. The diagram and information herein is compiled from many sources, however a good single source for further reading is Dreaming: Understanding the Biology, Psychology and Culture Vol.1 (Hoss, Valli, Gongloff, 2019). The horizontal scale is sleep time in hours, and the vertical the stages of sleep. In simple terms, it shows that we cycle between various sleep stages multiple times each night: NREM sleep stages (deep stage 3 and 4, and lighter stage 2 – sometimes called S sleep for synchronized sleep) as well as the REM stage (also known as paradoxical or D, for desynchronized). Figure 1-1 Sleep Architecture The REM cycles continue throughout the night, in approximate 90-minute periods. Although shown as sharp distinctions the transitions can be more fluid than the diagram implies. We typically go through four to six dream periods in an eight-hour night, with mental activity or visual dreams occurring to different degrees in parts of all stages, which might be surprising since we are often unable to recall even one of the dreams. In adults, REM sleep takes up about 20–25 % of the night; the NREM stage 1 (N1), about 2–5%; the NREM stage 2, (N2), approximately 45–55%; and slow wave sleep or NREM stages 3 and 4, (N3 & 4) approximately 20 percent. When dreams are considered to be recall of mental content from sleep, lab research has demonstrated of from 80% to 95% dream recall after awakening from REM sleep and 40% to 60% recall after awakenings from NREM sleep (Nielsen, 2000; Schredl et al., 2009, 2013; Schredl, Hoffmann et al., 2014), higher percentages among young adults. 2 © Robert J. Hoss Sleep & Dream Stages As a reference the material above and below comes from various generally available sources (some noted), however a thorough discussion can be found in Dreams:Understanding the Biology, Psychology and Culrture (Hoss, Valli, Gongloff, 2019) with particular reference to a section by Michelle Carr and Elizaveta Solomonova, “Dream Recall and Content in Different Sleep Stages” Awake State The waking state is characterized by relatively unsynchronized beta and gamma brain waves (12-30 Hz and 25-100 Hz respectively). We are awake, alert, and our thinking rational and self-reflective. Stage 1 (NREM1 or N1) Stage 1 (N1) sleep is the stage of falling asleep during which we may feel drowsy or if awakened often believe we never slept. Typically, this stage represents only about 5% of the total sleep time. Brain wave activity gradually slows down and transition from relatively desynchronized to more synchronized but slower alpha waves with a frequency of 8-13 Hz, and then to theta waves with a frequency of 4-7 Hz. Our muscles are still active and eyes move, breathing gradually becomes more regular and the heart rate begins to slow. Hypnagogic sleep: Often at sleep onset we awake with a jerk, sometimes recalling some dream-like images. This is known as a period of hypnogogic sleep, or light sleep where both Alpha and Theta brain waves are observed. Various studies show (Nielsen, 2000) that between 31-76% of stage N1 sleep reports contain dream imagery. The content or images are often brief and strange and might contain sound, sometimes snippets of a day’s event, sometimes an element that might appear as a theme later in the night’s dreams. At times there may be sensory feelings or a feeling of levitation or moving in space or floating above the bed. At times creative thoughts arise; artists often use the images in this state for inspiration. Stage 2 (NREM2 or N2) Stage 2 (N2) is a stage during which muscle activity decreases still further and conscious awareness of the outside world begins to diminish completely. If any sounds are heard, the sleeper is not able to understand their content at this point. Brain waves during N2 are mainly in the theta wave range (as in stage 1 sleep), but in addition N2 is also characterized by two distinguishing phenomena: sleep spindles (short half second bursts of brain activity about 12-14 Hz) and K-complexes (short 1 to 2 min complex spikes and waveforms). These are thought to suppress response to outside stimuli and aid in memory consolidation and information processing. We pass though N2 stage several times during the night, so we spend more in N2 sleep than in any other single stage, about 45%-50% of total sleep time for adults. The percentage of mentation or dreaming from N2 awakenings is reported to be about 60% to 70%. N2 dreams in relation to REM dreams tend to contain more fragments of recent waking life episodes and be: less frequent and shorter; less emotional; less perceived content (dream figures, places, actions); less personally involving; less bizarre; more thought-like. On the other hand, some N2 dreams have been found to be somewhat indistinguishable from REM dream reports. 3 © Robert J. Hoss Stage 3 (NREM3 or N3) Stage 3 (once known as 3 & 4) is also known as deep or slow-wave sleep (SWS) or Synchronized sleep since the brain waves are more regular and lower frequency characterized by delta brain waves with a frequency of around 0.5-4 Hz, along with some sleep spindles, (although much fewer than in stage 2). Normally at sleep onset there is a rapid movement from stage 1 sleep to stage 3 and during this stage the we are even less responsive to the outside environment, unaware of any sounds or other stimuli. Stage 3 sleep periods are longer and present during the first half of the night, particularly during the first two sleep cycles and represents around 15%-20% of total adult sleep time. What is now described as stage 3 was once split into 3 and 4 (stage 4 when delta waves exceeded 50% and when brain temperature, breathing and heart rate and blood pressure was lowest). Pulse, respiration rate and blood pressure are lowered and no eye, facial or body movements are noted. Muscles relax, although body jerks may occur. It becomes more difficult to arouse the person and if awakened, and if awakened they often feel groggy and take some time before attaining normal mental performance. This is also the stage during which parasomnias like night terrors, sleep-walking, sleep-talking and bedwetting occur. Dream reports or mental activity from N3 are less frequent than in REM at around 50% to 65% (Cavallero, 1992) versus 80% to 95% from REM as noted earlier.