Chapter 10: Sleep and Dreams

What is the neural networks of sleep?

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

What is the chemical stimulation of frontal dopamine system?

Sleep research is very difficult

Do rats have REM sleep? Yes

Having REM sleep appears to go with having a brain If you want to learn more check out Why are phospholipids so suitable to build membranes?

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 2

Dreams, hallucinations, and Wernicke’s Aphasia are all  related through the same background processes

What is the norepinephrine?

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

∙ Locus coeruleus

∙ Raphe nucleus

∙ Tuberomammillary nucleus

These networks are mutually inhibitory

∙ When one is active, the other is inactive (vice versa)If you want to learn more check out What are the symptoms of hypoglycemia?

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 If you want to learn more check out What is the function of the congress of industrial organizations?

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 are the discrete random variables?

Back to front – posterior to frontal in the brain, goes from  complex to less complicated Don't forget about the age old question of What is a camera obscura?

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

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

If you want to learn more check out What is the importance of parental psychopathology?

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

New Conclusion:  

∙ 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:  

two-stage hypothesis

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.