Chapter 10: Sleep and Dreams
Most dreams we have aren’t anxiety dreams
Most of our dreams are unremarkable and unrememberable
Recurring dream refers to the theme or content of the dream
We know fair amount about sleep but we don’t really know about dreams
Within the semantic memory:
Biggest conundrum in sleep and dreams: Do other animals dream?
∙ No way of knowing or proving it
Sleep research is very difficult
Do rats have REM sleep? Yes
Having REM sleep appears to go with having a brain
Dreams do not only occur during REM sleep
Dreams can occur in other stages, except stage 1, but most occur during REM sleep
REM sleep follows which stage of sleep? Stage 2If you want to learn more check out How can water form hydrogen bonds?
Dreams, hallucinations, and Wernicke’s Aphasia are all related through the same background processes
Don't forget about the age old question of What are the stages of behavior change?
Hallucinations – loss of touch with reality
Schizophrenics are more capable of tickling themselves
You can’t tickle yourself because you brain can distinguish between yourself and others
The Neural Networks of Sleep
Sleep as a state and dream as a phenomenon are different things
The VLPO (ventrolateral preoptic nucleus) in the hypothalamus is important in promoting sleep
An arousal network also exists We also discuss several other topics like What does a stock market crash mean?
∙ Locus coeruleus
∙ Raphe nucleus
∙ Tuberomammillary nucleus
These networks are mutually inhibitory
∙ When one is active, the other is inactive (vice versa)
Most people sleep an average of 7 and ½ hours a night As time passes, people often sleep less and less Old people sleep more than babies = FALSE
During sleep, temperature drops, cortisol goes up, not much growth
Dolphins can put half their brain to sleep
∙ Their brain size may be an evolutionary effect of their extensive communication
Mammals have laterization of functions
There is a pattern of REM sleep and wakefulnessIf you want to learn more check out What define a binomial variables?
Back to front – posterior to frontal in the brain, goes from complex to less complicated
The further back, the more complex
Norepinephrine levels are very low during all stages of sleep, especially REM sleep
Serotonin is high during waking and is even higher during REM sleep
Which one would be most likely to be associated with dreaming? Serotonin because it’s high during REM sleep.
The brain regions responsible for the sleep and awake states are mutually inhibitory, resulting in either sleep or wakefulness, but not both simultaneously
We also discuss several other topics like What are the materials needed to create mosaic?
Activity in the preoptic area results in sleep, inhibits the brainstem systems
PGO don't produce the dream; they give the order
Ventral frontal cortex + parietal cortex associated with spatial neglect = dreams
We also discuss several other topics like What are the kinds of impulsivity?
Sleep is triggered by activity in the locus coeruleus: FALSE
Which statement is true of neurotransmitters in REM sleep?
Serotonin is high, norepinephrine is low.
Ventromedial frontal lobes: another dreaming locus and also involved in schizophrenia
VmPFC implicated in lucid dreaming, also shows decreased activity in schizophrenia
Lucid dreaming is not like actual dreaming
Brain During REM sleep
PGO waves spread from pons to the lateral geniculate nucleus and occipital lobe
∙ Tell the forebrain to generate a dream sequence
Experiment comparing rat brain activity during exploring a maze versus during REM sleep
∙ Rem is controlled by cholinergic brainstem mechanisms whereas dreaming seems to be controlled by dopaminergic forebrain mechanisms ∙ REM and dreaming are different processes
Is Non-REM dreaming the same in nature as REM dreaming?
∙ Most non-REM dreams seem to occur at the very beginning of sleep or very near the end of sleep ∙ Non-REM dreams are ON AVG more logical ∙ BUT there are non-REM dreams that are just like REM dreams
∙ Therefore, there can be REM-like dreams without REM
o NO perfect correspondence between REM and dreams
Forebrain lesions and dreaming
∙ Damage or lesions to the forebrain much less likely to be fatal in consequences than pontine damage ∙ Multiple documented reports of forebrain lesions that eliminate dreaming while completely sparing the brainstem. Most suspected site is the region where
parietal, temporal, and occipital cortices meet (area associated with spatial neglect)
∙ Whatever produces REM must produce dreams ∙ We must rely on nature’s experiments such as those who have strokes
o Those with strokes in the brainstem often fatal, especially deeper down by the pons
o Damage to the forebrain is much less likely to be fatal
Vivid dreams correlated with activity in mesolimbic dopamine syst4em
Dorsolateral prefrontal cortex less active during REM (lateral is external and medial is internal)
Amygdala more active during REM
FMRI studies show vivid dreams associated with amygdala activity
Chemical Stimulation of Frontal Dopamine System
∙ L-dopa not only produces positive psychotic symptoms but also results in vivid dreaming and nightmares
∙ Those with Parkinson
Nucleus Accumbens – play central role in reward circuit Book: The Brain and the Inner World by Mark Solms - Combines neuroscience and psychiatry with Freud
PAC – Spatial neglect
Amygdala – emotional content of dreams
Dream content is result of brain trying to comply with PGO orders to generate a story (Activation-synthesis theory)
Associations areas are what contribute to dreams
No two people’s strokes are the same or damage the same area to the same extent
Hard to correlate areas of stroke damage with behavioral phenomenon
Dreaming and activation:
Stage 1: the forebrain is activated during sleep (the old term “reticular activating system”)
Stage 2: dreaming occurs only if the ventromedial frontal dopamine circuit is activated.
The ventromedial prefrontal cortex (vmPFC) tells the TOP cortex to generate a dream
Which statement is true?
PGO waves send the signal for a dream to be produced.