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54 Cards in this Set
- Front
- Back
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what are some characteristics of dreaming? |
- state of consciousness - brain is relatively isolated from the external sensory environment - internal, brain-generated conscious experiences, often hallucinatory in nature - |
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review the major timeline milestones for dreaming |
on slide 3 |
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what is the best predictor of whether someone is dreaming? |
the EEG response if you see that someone's EEG response looks like they are in REM sleep (they waves look as they do when someone is awake) and you go int he room and askthem if they were just dreaming, most of the time they will say yes |
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describe the differences between REM associated dreaming and "hypnagogic reveries" that occur during stage 1 sleep immediately after dream onset |
REM associated dreaming: - elevated arousal level¸ - feeling of being asleep - eye movements - dreaming (organised sequence of events) hypnagogic reveries: - low arousal level - often feeling of being awake -little or no eye movement - floating from one thing to another, not an organised sequence of events happening serially in time |
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Dement and Kleitman discovered that dreams occur on average how many times a night? |
5 to 6 times a night |
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what is one influential theory for how a dream is generated? |
Activation-Synthesis Theory |
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who is this theory by |
Hobson and McCarley |
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describe the activation synthesis theory (and try drawing it with all of the arrows!!) |
so basically you have the brain stem, and when the cells in the brain stem get very active REM sleep occurs, and when REM sleep occurs, this causes internal forebrain activation: sensory cortex, motor cortex, limbic system in the sensory cortex: visual and auditory somatosensory - activated and this creates the sensory experience of the dream in the motor cortex: the motor cortex is activated but the execution of these motor commands is inhibited before the spinal cord - and this influences your behavior during sleep in the limbic system: the amygdala and hippocampus are activated which influences the emotional content of your dream
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the title of this theory (activation syntehsis theory) basically means: |
the name comes from the fact that there is this activation of the brain and this activation in the brain is combined (synthesised) |
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what do the brain imaging studies during REM sleep show: |
during REM sleep, there is less activity in some areas and more active in other areas |
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during REM sleep, there is less activity in the: |
- parietal lobe - frontal lobe (prefrontal cortex - dorsolateral) - cingulate cortex (part of the limbic lobe) |
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during REM sleep, there is increased activity in the: |
- the visual pathway - the motor cortex in both hemispheres |
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describe an example of functional uncouppleing that occurs (de-correlation) of two brain areas during REM sleep |
during REM sleep, the visual thalamus, and the posterior cingulate cortex are uncorrelated the posterior cingulate cortex is involved in the rational processing of information so this indicates that while you are dreaming, you are not rationally processing the visual info that you experience so for example when you see a pig fly you arent processing this as being irrational, you are accepting this as it is but the same study shows that the visual thalamus and the visual cortex are highly correlated during REM sleep (which makes sense) |
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what is this decorrelation phenomenon called? |
a functional uncouppleing of activity in certain areas of the brain |
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there appears to be a functional uncouppleing (de-correlation) of activity in certain areas of the brain from those highly activated during REM sleep this phenomenon may account for some characteristics of dreaming, such as: |
- unsupervised dream content - bizarre hallucinatory nature of dream content - lack of memory encoding and storing of dreams (the cingulate cortex is in the limbic system and also plays a role in memory) |
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why is the visual system (V1) and the prefrontal cortex (PFC) highly correlated and synchronized during waking? |
it because it serves as a functional "supervisor system" it is a way of analysing the visual info that you process in the brain and of comparing this visual input to your past experiences and to your expectations in order to make sure that what you are seeing makes sense, and if it doesnt make sense, as a way of processing and trying to understand why the visual input you are receving doesnt make sense so the fact that the prefrontal cortex and the visual system are highly synchronized during waking allows for this functional "supervisor system" |
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what happens to the synchrony between the prefrontal cortex and the V1 visual system during REM sleep? |
there is this uncoupling of brain systems the brain activity in the PFC is no longer synchronized to the brain activity in the V1 - so essentially during REM sleep, there is this failure of the supervisory system during a dream:you have visual input, but the PFC isnt connected to what you see so you dont have this abilitiy to process your situation and understand that you are just dreaming and that whatyou see (ec: someone flying) cant possibly be true)because the PFC and V1 arent connected during dreaming this makes it so taht we cant influence our dreams, and we cant be aware that we are dreamingand that is why dreams feel so real to us and we are scared by what we see sometijmes because we cant understand taht we are only dreaming - we think htat all of the visual info we see while we are dreaming is real |
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what is this phenomenon described as? |
the Oscillation Model of Dream "Hallucinations" and essentially this desyncrhony between these two brain systems is what influences the hallucinatory experience of dreams |
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in an experiment, they applied pulses to the prefrontal cortex in order to synchronize the brain activityin the PFC to the activity in the V1 what happened? |
when this synchronization was artifitially put in place during REM sleep, participants reported being aware that they were dreaming and they also had some control over the dream content |
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what is lucid dreaming? |
if activity in the V1 starts to match up to activity in the PFC than than you can start to influence your dreams and control what you dream about this is called lucid dreaming |
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can dreaming occur without REM sleep? |
yes |
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give evidence to show this: |
- dreaming also occurs something during NREM stage 1 sleep and other stages of sleep outside of REM sleep - case studies: humans who had damage to the pontine brainstem and who no longer had REM sleep still reported having dreams - specific forebrain lesions have been shown to cause the cessation of dreaming (they used to make forebrain lesions to try and treat schizophrenia, many of these patients they no longer dreamed, or dreamed very little, even though they still went into REM sleep!! - loss of dreaming after this procedure in 70 to 90 of patients) |
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Dopamine is connected to dreaming |
mmm |
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what happens when there is a disruption of dopamine input to the frontal cortex (which occurs when the brain lesion is administered to the frontal cortex, and also with medicine) |
- there is a loss of dreaming |
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what happens when there is overactive dopamine transmission? such as because of: - schizophrenia - I-DOPA (drug for Parkinson's disease that increases dopamine) - stimulant drugs such as cocaine and amphetamine |
hallucinations and delusions occur |
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all this shows that dopamine probably plays an important role in dreaming |
mm (this has some similarities to Freud's link between dreaming and psychosis) |
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also another point to keep in mind: |
the dopamine pathway (mesolimbic dopamine system) goes to the frontal cortex but the frontal cortex is disconnected from the rest of the brain during dreaming, which prob adds to the surreal hallucination characteristic of dreaming |
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what else shows that dreaming and REM sleep do not always occur together? |
- anti depressant drugs (serotonin (5-HT) and noreadrenaline (NA) are known to lead to a pronounced suppression of REM sleep - the drug increases serotonin and noreadrenaline which leads to a suppression of REM sleep |
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describe a study that shows this antidepressant drug effect on sleep |
patients taking antidepressant drugs had the same total sleep time as people on the placebo drug, but people on the antidepressant drug didnt start going into REM sleep until later into the night and they had less episodes of REM sleep |
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did the patients on the antidepressant medication still report dreaming? |
yes they did even though REM sleep is reduced, dreaming bounces back from that and occurs during stage 1 sleep instead (people on antidepressant medications show the most dreaming during Stage 1 sleep and barely any dreaming during REM sleep) so even though REM sleep is mostly gone, the patients still dream |
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results from the study: see slide 16 for the graphs |
Results:White bars - Placebo: most dreaming during REM sleep (but notethat dreaming also occurs during other stages!) Black bars - Clomipramine: REM sleep and associated dreamingabolished; trend toward compensatory increase in dreamingduring non-REM sleep (N) |
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so what are the implications of these results? |
significant dreaming occurs despite the pharmacological (in some casescomplete) suppression of REM sleep. These studies confirm that dreaming is not confined to onlyREM sleep. Further, brain mechanisms that control REM sleep anddreaming may overlap, but are not identical. |
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dream theories |
there is a long standing interest in the significance of dreaming |
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info from slide under dream theories: essentially saying that there are many different views about dreaming and dream content and why we have the dreams we do and unanswered questions |
A significant amount of work has attempted to use dream content to assess the significance of dreaming.In other works, there is an assumption that the content of our dreaming has some relevance, and thisrelevance can be used to infer the potential functions of dreaming. This kind of reasoning is central to,for example, Freudian theories of dreaming (see below). On the other hand, how do we know that we actually dream? Maybe we have a tendency to make upstories upon awakening, or are confused, or that what we perceive as “dreams” during sleep are actuallybursts of activity in the brain during the period of awakening (sleep-waking transition)? Further, the large majority of dream content is apparently not accessible to conscious recollectionduring subsequent waking, severely limiting the use of content analysis to understand the functions ofdreaming. |
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what are 9 typical characteristics of dream content |
- are rich in sensory detail - may reflect our own daytime thoughts, interests, and concerns (still debated) - may reflect anxieties you have (still debated) - involves personal participation (you are not just a passive observer) - there is an absense or significant reduction of voluntary control over mental activity - little self awareness of one actual state (sleeping, immobile, in bed., etc.) - there is a lack of insight into the delusional nature of the dream - dreams are often highly emotional - dreaming is an amnesic state (this means that we cant remember our dreams well we dont have a strong link between the part of our brain that is dreaming, when dreaming, and the part ofthe brain that consolidates memories) |
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what are the three current dream theories: |
- psychodynamic theory - activation-input-modulation theory - neurocognitive theory |
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who are the advocates for psychodynamic theory? |
Freud and Solms |
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what do they say about dream generation? |
they say that dreams represent unconscious wishes, desires, impulses, and appetive motivations basically things taht arent socially appropriate but are our primal impulses get expressed in dreams |
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what do they say about dream amnesia? |
they say that dream content is actively suppressed due to the inapropriate nature |
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what do they say about how dreaming is related to waking consciousness |
they say that the true dream content is censored due to its nature dreams are unlike waking consciousness |
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what do they say are the functions of dreams and sleep? |
- we get sexual wish fulfillment and we are able to get this fulfillment without being consciously aware of it because we are sleeping -- that way we can be ignorant of our id dream/sleep functions: preserve sleep during expression of unconsciousdesires |
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what do they say about dream content? |
- they say that dream content is related to our experiences thoughts and desires - dream content is meaningful (not random) - and it is top down induction |
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also extra, what does Solms argue about specifically? |
argues about dopamine being released during dreams, and dopamnie is associated with rewardswhcih makes sense with dreams being ways of acting out our desires |
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who is the proponent of the activation-input-modulation theory? |
J.A Hobson he thinks that dreams are brain activations that happens a couple times a nighthe sees it as internal input that is generated by the brain |
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what does he say about dream generation? |
he says that dreams represent brain activation, internal input, and the specific release patterns of neuromodulators (high ACh, low 5-HT, NA, hist.) during REM sleep, a lot of these wake neurotransmitters are really lowwhich, he says, creates this bizaree schizophrenic type of experience |
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what does he say about dream amnesia? |
lack of neuromodulation and deactivation of prefrontal cortex disrupts memory storage basically he says that there is sleep amnesia because some brain systems are not active during sleep and therefore cant consolidate the dream |
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he also says that dreams are unlike waking consciousness, they are more like: |
delirium, hallucinations |
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what does he say are the functions of dreams and sleep? |
- possible creative function - memory consolidation; attempt by brain to interpret random sensory signals |
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what does he say about dream content? |
- says it is unrelated to waking experiences, thoughts or desires - not meaningful - mostly random - bottom up induction (his view is that dreams dont mean anything) |
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who are the proponents of the neurocognitive theory for dreams? |
D. Foulkes, G.W. Domhoff |
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what do they say about dream generation? |
they say that dreams represent an activated brain lacking sensory input and self-awareness/reflection |
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what do they say about dream amnesia? |
they say it is due to lack of conscious cognition and context |
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what do they say about the functions of sleep and dreaming? |
- they say that it possibly doesnt have a function, but that it could have "meaning" - attempt by brain to interpret random sensory signals |
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what do they say about dream content? |
- related to waking experiences, thoughts, and memories - top down induction (argues that at least some aspects of your waking life pop up in your dream) |
