Psych 169 - Ch. 23: Sleep, dreams, and hypnotic states

non-REM sleep

p. 374 A quiet or deep sleep state characterized by the absence of motor activity or eye movements and more regular, slow brain waves, breathing, and heart rate. The overall firing rate of neurons is as high as in waking states, but the pattern is quite different, with the EEG dominated by long, slow waves rather than complex, fast ones

In REM sleep, the brain stem blocks motor commands at the level of spinal motor neurons so that whatever is going on in motor cortex does not result in physical activity

p. 374 At the same time, the pons, amygdala, hippocampus, and anterior cingulate are especially active, as are parts of the visual system and visual association areas, but the dorsolateral prefrontal cortex is much less active than during waking.

Within the brainstem are ___________ and ____________, which reciprocally activate and inhibit each other and control the switching of states.

p. 374 Cholinergic REM-on nuclei, aminergic (both norepinephrine and serotonin) REM-off nuclei.

REM sleep

p. 374 Rapid eye movement sleep, a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active. brain is highly active and the EEG resembles that of waking, although paradoxically, the sleeper is harder to wake up than during non-REM sleep. Controlled by the reticular formation in pons in the brainstem.

Blocking of sensory input happens at the _______ in non-REM sleep and at the ______ in REM sleep

p. 374 thalamocortical level, periphery

Most dreams are never recalled.

p. 375 When woken from non-REM sleep, people typically say either that nothing was going on in their mind or that they were thinking. When woken from REM sleep, people typically report that they were having complex, much longer, and often bizarre dreams; sometimes very bizarre.

3 categories of bizarreness in dreams

p. 376 By Hobson. Incongruity: The mismatching of features of characters, objects, actions, or settings. Discontinuity: Sudden changes in these elements. Uncertainty: Explicit vagueness. The way characters and objects are transformed in dreams follows certain rules but that changes of scene and plot do not

Scoring system for dreams (by Hall and van de Castle)

p. 376 counts such elements as settings, characters, emotions, social interactions, and misfortunes, all of which show remarkable consistency across times and cultures, with reliable sex differences, and reliable differences between the dreams of adults and children. But there are problems with generalising about dream content because of the effects of the method of collecting reports. only some dreams are recalled on waking, some fade faster from memory after waking, and further selection can occur when people are asked to write a report or describe their dreams. So the occurrence of bizarre or interesting dreams may be exaggerated

Antti Revonsuo's studies of bizarre dreams

p. 377 The most common type was bizarreness of dreamers' semantic knowledge about dream characters. Features intrinsic to the representation of a character were less often bizarre than the relationship between the character and the setting or the location.

Dream research seems to provide a perfect context in which to look for the neural correlates of consciousness (NCCs).

p. 377 Various physiological, neurochemical, and behavioural variables can be correlated with subjective descriptions of dreams. Suggests: either reducing the experiences entirely to physical states, or equating the experiential with the physical, leading to idea of only one space and one concept of dreaming sleep (instead of 2). This has supported research of sleep/dreaming, and allowed scientists to map the 3 major states according to their physiology.

AIM model

p. 377-378 By Hobson. Depicts a unified "brain-mind space". The various sleep states can positioned in this brain-mind space by measuring them along 3 dimensions: A, I, M, and time as a fourth dimension. These variables and the normal sleep stage cycle can be represented by movement from one region of the space to another. Large areas of the space remain empty and the different states are discrete SoCs. They are not points, though, more like clouds in state space. Problems: Map is crude, has only 3 dimensions, and reality is much more complicated. - But not serious since this provides a way of relating sleep states to other supposed ASCs and to the various neurotransmitter systems that control the overall state of the brain, and more detail and further dimensions could potentially be added.

Correlation between REM and dreaming is real, but not perfect.

p. 378-379 1. Dreaming is reported in about 70-95% of awakenings from REM sleep and roughly 5-10% of non-REM sleep, while mention of some sort is reported from about 50% of non-REM awakenings. - Being physically in REM sleep does not guarantee dreaming, and dreaming can occur without the physiological state of REM. 2. Damage to the ventral-mesial quadrant of the frontal lobe (emotional motivation) or to the parietotemporo-occipital (TPO) junction (part of sensory areas) reduces or eliminates dream recall while leaving REM sleep essentially normal. - REM is neither a necessary nor sufficient condition for dreaming. 3. Human fetuses spend about 15 hours a day in REM sleep, less than babies and adults. But they cannot have dreams like adults do since dreaming depends on prior experiences and developed cognitive abilities that babies lack. - REM can occur when dreaming seems unlikely or even impossible. 4. Many birds or mammals experience REM sleep. When mammals dream, we can see their eyelids moving and their body twitching. We can guess that some of them might be enjoying complex visual/auditory images, but they cannot construct narrative structures or describe their dreams in words. - We cannot simply assume that REM = dreaming.

One possibility: The _______ and ________ can never be reduced to, or equated with, each other; the fathomless abyss can never be crossed.

p. 379 physiology, phenomenology

Another possibility: With further research, and more complex/realistic understanding of brain states and neurochem, we will learn exactly how brain states relate to the experience of dreaming.

p. 379-381 1. The contents of a dream can be related to eye movements. 2. The same cortical areas appear to be involved in rapid eye movements as are involved in waking eye movements 3. fMRI scans suggest that REMs are visually-guided saccades that reflexively explore dream imagery 4. The same sensory areas are activated when something is seen or heard as when it is imagined or remembered, and the same seems to be true of dreams. - Known patterns of activation are starting to make sense in terms of dream content. 5. Animal studies have revealed more about the connections between learning, memory, and dream content. 6. Revonsuo: The harder it is for the brain to construct a certain kind of integrated image, the more likely it is that such an image will fall apart or show bizarre failures of binding during dreams.

Are dreams really experiences? Some doubt this.

p. 382-383 1. The self: Although I am sure that 'I' was dreaming, the self in the dream was not like my normal waking self. The dream-self never realized it was dreaming, accepted the dream as reality. So the dreamer might not have been really me. - Metzinger: This does not matter bc there was a kind of phenomenal self in the dream. 2. Lack of insight: There is a qualitative alteration in the overall pattern of mental functioning but the experiencer does not realize this. - By Tart's definition of an ASC, an ordinary dream is not an ASC. But a lucid dream is (bc the experiencer does realize it is a dream). 3. Status of the dream: if I start to doubt whether I really did have that dream, the only evidence to call on is my own memories, and those are vague and fade fast. 4. Alfred Maury: Dreams do not happen in real time, but are entirely made up in the moment of waking up. - But this is false: Research shows that dreams take about the same time as would waking events. Suggests that dreams are not concocted in a flash on waking up, but really do take time.

cassette theory of dreams

p. 383 By Dennett. The brain holds a store of potential dreams recorded and ready for use. On waking from REM sleep, a 'cassette' is pulled out of storage, to match an external stimuli, and it seems like we were dreaming. So: Dreams do not exist. There are no events or images presented 'in consciousness', but only recollections of dreams that were never actually experienced. Dreams are not experiences we have during sleep.

Dennett: Equivalent of cassette dreams might be composed during _______.

p. 383 the prior REM sleep

Now have 2 theories: the normal theory that dreams are conscious experiences during sleep, and the new theory that dreams are composed unconsciously during sleep and then 'remembered' on waking up. Can we tell which is correct?

p. 383-384 Seems: No. This is a difference that makes no difference. There is no Cartesian theater in which the dreams either were, or were not, displayed. Left with two theories that seem empirically indistinguishable: One requires events to be "presented" or "displayed" in consciousness, while the other does not.

On the one hand, we know that dreams occur in real time; on the other, we know that people often wake from dreams in which the event that woke them fits the end of a long dream story. How?

p. 384 Retro-selection or backward-weaving theory of dreams (by Blackmore). During REM sleep numerous brain processes are going on at once, none of which is either in or out of consciousness. On waking up, a story is concocted by selecting one out of a vast number of possible threads running through the multiple and confusing scraps of memory that remain. The chosen story is woven backwards to fit the timing, but is only one of many such stories that might have been selected had a different event woken the dreamer up. So: There is no version of the story that counts as the actual dream, consciously experienced at the time. Resolves the conflict, but means that there is no correct answer to question "what did I really dream about?". Dreams are not conscious experiences. They don't occur in consciousness, but then nor does anything else.

False awakening

p. 385 A dream of having woken up. The person acts like they would getting ready in the morning, until they really wake up and start all over again. At this point they may be sure they are really awake, but again may not be. Some people report experiences similar to hypnagogic hallucinations. This suggests that it may sometimes be impossible to know whether one is awake and hallucinating, or only dreaming one is awake. - In the first case, the bedroom is real even if the hallucinations are not, but in the second, the whole room and everything in it is dreamed.

metachoric experience

p. 385 Experiences where the whole environment is replaced by hallucinations. For bizarre, self-reported supernatural experiences or even some drug experiences: Without physiological monitoring we cannot know whether the person had their eyes open, as often claimed, or was fast asleep.

Falling and flying dreams

p. 385 Most of these dreams are not lucid dreams, but falling and flying can sometimes alert people to their state, leading to lucidity (clarity of experience).

prelucid dream

p. 386 By Celia Green. In a dream, we experience critical doubt prompted by strong emotions, by incongruities in the dream, or by recognizing recurring themes from previous dreams. We ask "Am I dreaming?". But it is common for dreamers to give the wrong answer.

lucid dream

p. 386 Term created by Frederik van Eeden. A dream in which you know during the dream that you are dreaming. Many feel like they can control their dream: many claim that once lucid they can fly or float, take charge of the course of their dream, or change the objects and scenery at will. But this is just a correlation b/w increased consciousness and the ability to control the dream, not a definite conclusion.

Before, many psychologists rejected claims of lucidity: Self-reflection and conscious choice are impossible in dreams, so lucid dreams must really occur before or after sleep, or during micro-awakenings. But they were proven wrong.

p. 387-388 Experiments by Keith Hearne and Stephen LaBerge. Problem: In REM sleep the voluntary muscles are paralyzed, so a dreamer who becomes lucid cannot indicate to the researchers that they are lucid. Solution: Dreamer could move their eyes. So their lucid dreamer moved their eyes left/right 8 times in succession whenever he became lucid. The eye movement signals occurred during REM sleep.

The method of signalling from lucid dreams allowed some of the common questions about dreams to be answered bc correlations between dream content and physiology can now be timed accurately, and lucid dreamers can be given pre-sleep instructions to carry out particular activities during their dream and signal as they do so.

p. 389-390 1. How long do dreams last? - Time passes at the same speed in waking reality and in lucid dreams (shown by counting to 10). So lucid dreamers could accurately estimate the time taken by events during their dreams. 2. Do the eye movements of REM sleep correspond to dream events? - Lucid dreamers can deliberately create a dream event and then signal with their eyes when they are doing so. - Eye movements do reflect dream events, as shown by experiments. - Lucid-dream eye movements more closely resemble the smooth pursuit of waking vision than the saccadic eye movements associated with imagination. 3. Neural activation when physical actions are dreamed: - When lucid dreamers signaled as they performed different actions, the muscles that would be used by those actions in waking life twitched slightly during the dreams. - Physiological reactions in real life, while the person was lucid dreaming, match the content and timing of the dream's events.

Techniques that can help induce lucid dreams for people who cannot naturally experience them:

p. 390 1. First detecting REM sleep and then delivering a stimulus strong enough to increase arousal slightly, but not strong enough to wake the sleeper. - Dream Machine (Hearne): Detects changes in breathing and give a weak electric shock to the wrist. - DreamLight (LaBerge): Detects eye movements and then uses lights/sounds as stimuli. 2. Maintaining awareness while falling asleep, LaBerge's MILD technique, and other methods that increase awareness during the day rather than just at night: - We spend much of our time in a waking daze and if we could only be more lucid in waking life, it might carry over into dreaming. - Similar to meditation and mindfulness.