Sleep and Dreams

Signment Freud and Dreams

Published in 1899 - the Interpretation of Dreams (manifest and latent content)

According to Freud dreams have two functions:

• to let repressed desires and conflicts be expressed

• to protect sleep from being disturbed (dreams are guardians of sleep because the truth is distorted in dreams)

Not well received by scientific/medical community

Freud’s Predecessors

Alfred Maury - ‘Sleep and Dreams’ (1861)

• conducted experiments on himself

• concluded that we incorporate our sensory experience into dreams (e.g. alarm clocks)

Mary Whiton Calkins - ‘Statistics of Dreams’ (1893)

• dream reports

• congruity and continuity in dreams - waking life is integrated into our dreams (continuity hypothesis)

What did Santa de Sanctus do?

Used eletrophysiological instruments to measure sleep depth through presentation of tactile stimulation (esthesiometer) and breathing patterns (thoracic pneumonograph)

What did Sante de Sanctis find?

Noticed that:

• dreaming was less common during deep sleep compared to light

• dreams were more vivid in lighter sleep (end of night) & during bouts of irregular breathing

To understand a dream, you have to sum all the factors:

• fundamental state of the dreamer (experiences, intelligence, character etc.)

• the state of the moment (aspirations, passions, health)

• immediate experiences provoked by extrinsic conditions

What did Ramon y Cajal think?

Was very eager to prove Freud wrong and kept a dream journey for 16 years - felt that dreaming was one of the most interesting phenomena

Felt Freud was more concerned with finding a sensational theory than being committed to science

Simple definition of a dream

Any mental experience that occurs during sleep - thoughts, feelings and images that come into awareness and arise internally

Key feature of dreams

Can be really complex or simple - is a continuum from isolated sensations to wild & complex plot lines

Where does dream content come from?

• events from couples of days before or from several (5-7) days before (Eichenlaub et al. 2019)

• aspects of our experiences, objects, people and settings - combined with older memories

• most emotionally salient elements are more likely to be incorporated (Eichenlaub et al. 2018)

What do participants report when awakening?

Three reports:

• they don’t remember dreaming

• they know they were dreaming but don’t remember it (‘white dream’)

• they remember both

What may make a difference in asking for reports of dreams?

The way you ask might influence the answer - specific probes may help, for example, specific instructions and inclusion of smell and taste (generally don’t talk in terms of those senses)

Who discovered dreaming during REM

Aserinsky and Kleitman:

discovered REM & its cyclical nature (repeats every 90 minutes approx)

When do we dream? (sleep stages)

• more dreams during REM compared to NREM (Dement and Kleitman) (they found 80% vs. 7%)

However more research has found much dreaming in other stages too:

• NREM 2 was found to have 50-70% dreaming occurance

• NREM N1 dream rates are even higher (~75% - comparable with REM) - dreaming in first mins of sleep (hypnagogic dreams)

• NREM N3 around 50% dreaming

• N1 reports are shorter than N2 reports (shorter than REM)

Do all humans dream?

• 85-90% say they dream

• Most people who say they never dream, actually do dream (when awoken from REM in sleep labs - they do report dreams)

• It may be that 0.5% of adults cannot ever remember their dreams/may never dream - Jim Pagel (studies non-dreamers) found only 16 patients over 5 years that reported this

What is the best validated scale that measures dream content? What can it help us do?

HVC scale (Hall & Van de Castle, 1966)

• analysed 1000 dreams - 5 from 100 women and 100 men

• could infer from the responses to the scale, the dreamer’s personality, conflicts & concerns (supports continuity hypothesis)

What was the study assessing content of dreams?

Strauch and Meier 1996:

• 44 adults - REM awakening reports

• 2.6 characters

• 4.8 activities

• 75% contained emotions & negative aspects

• less than half had misfortunes

• 1.3 settings

• 44% unknown settings

• 26% familiar settings

• 19% vague settings

• 11% distorted settings

What people are present in dreams? Does this depend on the person?

• dreamer is often an active character rather than a passive observer (but not central focus)

• characters are usually adults (from adult reporters)

• strangers often present and have a role

• acquaintances & colleagues are more common than family members

• dreaming about prominent people/fictional characters is rarer

• animals = 40% in children’s dreams but only 5% in adults (but these change depending on cultural context - animals more salient = animals more in dreams)

• women = equal proportion of male & female, men = twice as many male characters (true cross-culturally & in children)

What kind of social interactions occur in dreams?

• neutral interactions generally - tend to be more negative than walking life

• aggressive or friendly interaction are mainly through words & gestures than physical contact

• aggression occurs with those that we clash with in waking life

• sexual interactions occur 12% for men and 4% for women (women = familiar characters more often than men)

What about the sensory part of dreams? How does this differ between people?

• very vivid and intense typically - several sensory aspects (visual, auditory, tactile etc.) - 10% REM and 30% NREM lack sensory imagery

• visual images very prevalent - sound reported 50% of the time - smells tasted and pain reported in less than 1% of reports

• if born blind (or blind before 4-5years) - do not dream with visual omegas but detail other sensations (if blind after 5-7 years - visual imagery that diminishes over time)

• deaf people report intense visual dreams

What about bizarreness in dreams?

• primarily occurs in actions (43%) such as impossibilities (flying or walking through walls) or improbable events (tsunami in uk)

• can be subtle (fork becomes spoon)

• may include uncertainties, incongruencies and scene shifts

• degree of bizarreness varies across sleep stages (most in REM) - 75% in REM, 60% in NREM, 33% in N1 REM

Does dream content depend on time of sleep?

Yes! Dreams vary depending on circadian time:

• longest, most vivid dreams when waking up late on a weekend following REM

• Wamsley et al. 2007 - greater length, bizarreness and emotionality during REM

What are typical dreams?

Dreams common across people and often happen multiple times e.g teeth falling out, being chased etc.

• Griffith Miyaki and Tago (1958) - first major study of dreams between american and japanese students - fewer fire and nudity dreams in americans but common themes included attacks, falling, trying to do something over and over, school and sexual experiences

What is the scale that measures typical dreams?

Typical Dreams Questionnaire

by Nielsen et al. (2003) - based on previous study (american and japanese students) and used on Canadian students:

• consistency in prevelence of typical dream profiles across time & region (in canada)

• stability in typical dream profiles (over four decades after initial 1958 study)

• studies in other countries reveal similarities in rank of themes

Typical dreams ranked

Zadra and Stickgold (2021):

• chased/pursued but not injured - 85% (more common in women - 86%)

• sexual experiences - 78%

• school/education related - 77%

• falling - 76%

• arriving too late - 65%

• someone being dead (who is currently alive) - 61%

• on verge of falling - 59%

What are nightmares?

highly disturbing dreams that often awaken the sleeper

bad dreams are negative dreams that don’t awaken the sleeper

sleep terrors are a distinct sleep disorder which takes place in N3

What is the prevalence of nightmares and their typical occurance?

• Occur in people of all ages (with a 100% lifetime prevalence)

• 10-30% of adults have a nightmare at least once a month (once a week may be clinical - 4% of people)

• 85% adult report at least 1 nightmare a year

When do nightmares occur?

• usually during second half of the night during REM - upon waking people quickly realise it was a dream and can remember what happened

• trauma-related nightmare tend to accurately replay elements from traumatic events

Themes of nightmares and bad dreams ranked

Robert and Zadra 2014:

• physical aggression - 49% (nm) 21% (bd)

• conflicts - 21% (nm), 35% (bd)

• failure or helplessness - 16% (nm), 18% (bd)

• health related concern & death - 9% (nm), 14% (bd)

• and many more

What are recurrent dreams?

Re-occurring dreams

• 70% or adult reports having at least 1 in lifetime

• 75% negative, 10% mixed, 10% positive

• 60% involve a challenge or threat

• children have fictional hostile agents whereas adults tend to have human real people

What is lucid dreaming?

Being aware of being in a dream (public interest is high in this)

varies from:

• pre-lucid (realisation/consideration of dreaming causes awakening)

• short lived lucidity

• lucid and maintaining mental abilities as if awake

having lucidity is not difficult but maintaining it is

there is a difference between lucid dreaming and lucid control - many people prefer to go with the flow of the dream (no documented benefits)

Important research in lucid dreaming

Alan Worsley (recorded by Hearne and LaBerge) - skilled lucid dreamer - signals lucid dreaming by moving his eyes far left and far right - EEG and EMG are at London science museum

Stephen LaBerge - exploring the world of lucid dreaming

What is the function of dreams? (multiple theories)

Francis Crick - REM sleep likely serves for reverse learning - brain erases memories replayed in the dreams we never remember - we dream in order to forget (Crick and Mitchison 1983)

Other theories following this publication:

• no biological or adaptive function

• help us solve problems

• evolutionary role

• emotion regulation

• memory functions

What is the Activation Synthesis Hypothesis?

Hobson & McCarley (1977):

• dreaming is a phenomenon as a consequence of the neurophysiologi of REM sleep (bottom-up view)

• dreaming is dismissed as unimportant

this postulated because:

• brainstem activated during REM & sends signals to cortex which creates images with actions and emotions from memory

• the frontal cortex = less activated so no logic or timing in the sequence of events - person tries to organise the content into logical story when awake

• no meaning in dreaming - but dreams are based on individual experience

What is the brajn activity like during dreaming?

Maquet et al. (1996):

pattern of brain activation may explain why dreams are the way they are, aside from brainstem & frontal cortex activity:

• activation of limbic system

• decrease in activity of the dlPFC (executive functions)

• activation of motor cortex

Can we read people’s dreams?

Potentially but with limitations:

Multivoxel pattern analysis using fMRI

Horikawa et al. 2013

• able to match activation of brain when ppts were exposed to certain stimuli with activity in brain during dreaming

• therefore pattern of activity could be matched to content of dream reports (objective study of dreams via pattern of brain activity)

^ many of the things people dream about are not real or based on existing stimuli (therefore could not find the brain pattern for these stimuli)

Examples of dreaming for problem-solving and creativity

Several examples:

Mary Shelly - Frankenstein

Paul Mccartney - Yesterday

Tartini - dreamed of devil playing violin & composed the music

• dreaming facilitates creativity by helping us problem solve (in explicitly)

• mendeleev - saw the periodic table in a dream (zadra and stickgold 2021)

3 other examples of problem solving dreams

kekule (german chemist):

dreamt his solution of how benzene is arranged (all atoms behave the same and have 6 atoms but all existing explanations didn’t make sense)

elias howe - mechanical sewing machine (had needle like spears thrown at him)

james watt - lead pellets for guns

when do these problem solving moments often occur (during sleep)?

during the hypnagogic period right before falling fully asleep

• thomas edison took advantage of this - metal spoon would clatter to wake him out of sleep

limitations of dreaming functioning for problem solving (& creativity)

creative breakthroughs are rare and tend to only happen when spending a long time working on something

dormio- an electronic version of Edison’s technique - records the dreams created by adam horowitz - early in development so not clear on results from this to provide evidence to support or be against this theory

still not sure on what happens with dreams later in the night (otto lowei’s dream for science experiment occurred later on in sleep) - seem to be rare and not remembered well

why may dreams have an evolutionary function? what the the key theory called for this?

• mechanism for simulating threats and rehearsing possible means of avoiding or surviving them

• called “threat simulation theory” (TST)

• empirical evidence is mixed - only small % of dreams with threats contain effective avoidance responses

• closer examination - 80% of dreams were fictional and the threats were unlikely to occur in real life

why might dreaming be adaptive? what is the key theory called?

Valli and Revonsuo (2009) - argued that dreams are biologically adaptive and lead to enhanced coping strategies:

• Coping Hypthesis (AKA Clinico-Anatomical Hypothesis) (top-down view)

• people dream about events in their life they find threatening

• problem solving occurs during sleep (“sleep on it”)

why might dreaming function as an emotional regulator?

‘nighttime therapy’ - Ernest Hartmann worked with trauma victims

• proposed that dreaming is a form of therapy - helps integrate emotional concerns and even traumatic events into existing memory systems (within safety of sleep) (NON LECTURE CONTENT - can mention REM and EMDR)

• dreams create connections between new and old memories (broader and looser than connections made during wakefulness

What did Rosalind Cartwright suggest about dreams and emotion regulation?

she studies emotion regulating function of dreaming in recently divorced men and women:

• dreaming or at least REM sleep dreams plays a role in regulating negative emotion

What was found in Cartwright’s study (1979)?

• three phases of dreams in a single night (in recently divorced individuals)

• first REM period - sets theme on emotional level

• 2nd and 3rd periods - past experiences related to that theme

• 4th and 5th REM - theme is extended into possibilities for future

more emotional intensity in beginning of the night - shows emotion regulation - this progression through the theme is beneficial to dreamer (however if stress is too high or too low - no progress)

consistent across decades (domhoff 1996)

What is the tetris effect and how does it relate to dreams for memory function?

Stickgold et al. (2000) showed ppts dreamed about tetris at sleep onset and reported unambiguous descriptions of the game.

Patients with amnesia has no recollection of playing the game (despite playing for 7h over 3 days) but also had dreams of blocks

How has dreaming been shown to improve task performance?

Wamsley et al 2007:

• Study on virtual maze where participants explored it and then took a 90m-nap

• Those who reported dreaming of the task showed 10x more improvement after their naps compared to those who reported unrelated dreams

What is the more recent suggestion of what dreams do?

• Dreams create narratives that unfold in our minds and allow us to experience thoughts, sensations and emotions

• Allow us to imagine and explore possibilities, the ‘what ifs’

• Proposed as the NEXTUP model by Antonio Zandra and Robert Stickgold, 2021

What research shows how the brain preferentially strengthens weak associations during sleep?

Stickgold et al. (1999) - used procedure from James Neely (1977) to find that:

• during the day - strong word primes resulted in 3x faster responses compared to weak primes due to the priming effect

• however, weak semantic primes were most effective (2-fold increase) in the presleep (middle of the night) and REM sleep conditions

• ^ in the REM condition, their brains were activating weakly related words (i.e. “thief”) 8x more effectively than strongly related words

• these results suggest cognition during REM sleep is different from that of waking and NREM sleep and may reflect a shift in associative memory systems (weak associations are tried out & strengthened)

What does the NEXTUP model predict?

• Stands for Network Exploration to Understand Possibilities

• That dreams allow us to explore network connections to understand possibilities (synthesis of information)

• Weak associations are explored to understand possibilities, supported by changes in neurochemistry

• Close concept to divergent or creative thinking, free-flowing thinking to generate a number of insights and potential answers to an initial question

Stages of the NEXTUP model

1. Hypnagogia (N1) - “What ongoing concerns was I just thinking about?”

2. N2 Dreams - “What associated recent memories can I find?”

3. REM dreams - “What remote, weak associations can I find?”