One of the stand-out features of humans, amongst all of the beasts on Earth, is our Dorsolateral-Prefrontal-Cortex (DL-PFC) and its capacity for organizing thoughts and behaviors. Let's think about your brain for a second...rewind to day one, you were just born, and your big head almost tore mother apart. Actually, it did a little. But as big as that head was, it was born waaay early of mature development. You don't remember, but you were a mess. For years. Without nearly constant supervision, any human child is helpless to take care of their own needs. Our brains start off so plastic and naïve and expandable that we are still uploading operating software into our 20's. At birth, we have more neurons and connections than we will ever have again, and afterwards a process of synaptic pruning removes pathways that don't get used during early developmental windows, so we can increasingly focus on those things apparently more important in our environment. But if this pruning of go-nowhere wires is a lessening, the thickening, or myelination of nerve tracts is a building-up. When neurons fire together and circuits are defined, a fatty insulation spirals around the involved axons, this sheath growing out of supportive glial cells (which are more numerous than neurons). But the growth of different brain regions occur on various time-lines, and the evolutionarily more recent brain structures take the longest to fully mature. This culminates with the DL-PFC, which generally levels off in the early 20's for women and mid-20's for men.
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In this study, a successful lucid dream epoch correlated to a red-hot activation of the Dorslateral-Prefrontal-Cortex. The large blue area covering most of the back of the head is the primary visual cortex, which deals primarily with actual sensory information coming through the eyes. Since we are not using our eyes in a dream to see, there is no processing occurring in this vast cortical swath. Even in lucid dreams.
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Although it's not exactly correct to say that a brain region only does one or two isolated things, we can think of the DL-PFC as the highest brain area for self-control. Without the mammalian brain the ancient "lizard" brain and the limbic system would make our decisions. Effective at primitive survival decision-making, these older brain regions can be left to their own devices in the right contexts, but are unequipped to adapt and learn and act with any complexity. Working-memory, the feature of consciousness that allows us to organize in real-time the series of activities leading to a non-routine goal, depends on the neo-cortex, including the frontal lobes. The most sophisticated and abstract human behaviors – social interactions and symbol manipulations – are processed in the DL-PFC. Although a late-teen or early-20-year-old may have more growth hormones pumping through their arteries and faster reaction time, they are still more dangerous behind the wheel because risk-aversion is ultimately determined by their still-developing DL-PFC. Damage to the DL-PFC can result in an excessively selfish personality, even if the person was conscientious pre-injury. As if the Super-ego had been wrapped in kryptonite, the Freudian-Id runs amuck. Also, a solid concept of the self depends on the right DL-PFC – when damaged a person may not recognize a picture of their face. When the left DLPFC is less active and the right DLPFC is excessive, this is indicative of major depressive disorder. Deficits in this brain region might underlie gambling, schizophrenia, and generally poor decision making and planning.
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Celia Green predicted in her 1968 book Lucid Dreams that lucid dreaming would correlate to REM sleep. Why this is often quoted I don't know; of course – vivid dreaming in general occurs during REM. But other dream researchers suspected that the DLPFC – which is usually in a quiet state during REM – might play an important role in lucid dreams. Regular REM sleep with regular dreaming is virtually devoid of any coherence over the cortex at the 40Hz frequency band. In contrast, lucid dreamers' EEG has displayed 40Hz frequencies in the DLPFC – indicative of conscious processing. Another study in 2010 found the right dorso-lateral prefrontal-cortex was active during two confirmed lucid dreams and was associated with performing tasks requiring metacognition – thinking about thinking.
Alan Hobson proposed that the type of conscious experience we have in regular dreams is similar to how we would have thought at an earlier stage of evolution. A proto-consciousness. Waking thought is more reflective. But lucid dreaming is more than waking-like. Lucid dreaming, with high frequencies in the DLPFC and high activation in the Amygdala, is a hybrid state not between waking and regular dreaming, but a separate state which has some qualities from both. |
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TMS stands for Transcranial Magnetic Stimulation. Basically, a pulse of magnetic energy is sent through a person's skull and can either excite a small cortical area or inhibit the area's function – the direction of change depends on the signal frequency and amplitude sent via the TMS machine. Years ago people starting wondering if TMS could be used to activate the dorsolateral prefrontal cortex during REM-Sleep, as a possible inducer of lucid dreaming capacity/likelihood – especially rTMS (the "r" stands for repetitive, because instead of a single magnetic pulse the machines sends a stream of magnetic energy over time). The problem with this is similar to an issue with MRI and fMRI ("f" for functional; streaming magnetic imaging). There is a loud clicking sound when the magnets in these machines discharge energy. Even if an rTMS application over the DLPFC could help induce lucid dreams there would be some drawback due to the lab setting and intrusive noise while trying to sleep. This may be overcome: a. People have had successful lucid dreams while in MRI tubes already, despite the noise (earplugs don't help much), b. As technology advances the noise and un-comfortableness issues might be worked-out. Maybe we will have discreet yet accurate home units. Wireless EEG caps with built in TMS. All controlled from your phone or tablet. You know that some of that is really coming.
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Why can children lucid dream if their DL-PFC is so immature? – I do think that some children, maybe many, lucid dream on occasion. It seems like a threshold is sometimes breached during disturbing dreams or nightmares. A realization occurs that what is happening – being chased or falling or whatever it is – is only a dream and escape is possible through waking up out of THIS dream. And maybe it goes beyond instances like these and children have lucid dreams even during pleasant scenarios. One thing I recall about my childhood dreams is that they were often "stronger," in that they were regularly very vivid, very "important" feeling, often scary, and were easy to recall. Not to mention repetitive; there were a few themes and locations – which were part amalgam of my waking life and part something else – that I had many dreams about and the world within felt real. This all sounds like a very fertile dream-life for having the occasional lucid dream. When young we go through growth spurts, and our brains are constantly learning. Those conditions require a lot of growth hormones, and a large flux of growth hormones and steroids is associated with strong REM-Sleep and wild dreams. Also, children face a world of uncertainty where so many experiences are new and can be interpreted as potential threats. Emotional concerns like these trigger "big" dreaming.
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So, the DLPFC is important for lucid dreaming. But it's only part of a larger network around the brain. There are both Dorsolateral and Ventromedial pathways that axonal currents travel while engaged in lucid dreaming episodes. There is top-down processing directed by your neocortex, and there is bottom-up influence as PGO-waves – activation bursts that propagate a wave from the brain-stem up and precede dense REM epochs.
The best take-home lesson I can propose for now is that if you perform tasks during the day which require a lot of work form the DL-PFC – things like problem-solving-intensive tasks that have roadblocks and hurdles and grueling hills – there may be a cross-over effect to your REM-Sleep. This way, during failures and misfortunes in dreams you might say to yourself "What's the best way to deal with this? Oh yea, this can't be happening." |