Sleeping, dreaming and learning

Question 1

Three states

Answer 1

REM
- wakre-like and ‘activated’ (high frequency, low amplitude or ‘desynchronised’) activity in EEG
- singlets and clusters of rapid eye movements (REMs) in the EOG channel
- very low level of muscle tone (atonia) in EMG channel

NREM
- all sleep apart from REM
- by convention divided into four stages corresponding to increasing depth of sleep

Question 2

REM’s dream features

Answer 2

• formed hallucinatory perceptions –> especially visual and motoric, occasionally in any and all sensory modalities
• can change rapidly, often bizarre in nature
• deslusional, unless lucidity cultivated
• self-reflection generally found to be absent
• lack orientational stability –> persons, times and places are fused, plastic, incongruous and discontinuous
• story lines to explain and integrate all dream elements in a single confabulatory narrative

Question 3

Memory sources

Answer 3

• memory systems active during REM sleep have extremely poor access to recent waking memories
• deficiency of memory –> may explain such distinctive and robust dream phenomena as orientational istability, loss of self-reflective awareness and failure of directed thought and attention
• dorsolateral prefrontal cortex –> significant deactivation during REM
• decrease in cerebral blood flow to frontal areas during REM

Question 4

Aminergic and cholingeric dominance

Answer 4

• shift/interaction from amingeric dominance in waking to cholinergic dominance in REM sleep

Aminergic neurons
- receptor that respond to amines or neurons that release noradrenaline (norepinephrine), dopamine, serotonin

Cholinergic neurons
- receptors that respond to acetylcholine

Hypothalamus, amygdala and basal forebrain are influenced by this interactions in ways that significantly amplify REM sleep generation or suppression

Question 5

AIM Model

Answer 5

= three dimensional model of brain-mind states

three (independent) processes which distinguish each state from one another
- level of activation
- input source/origin
- (neuro)modulation

Question 6

AIM: Level of activation

Answer 6

How much information is being processed by the brain?

• overall level of neural activity in the brain
• activation in waking an REM > NREM
• alert waking > quiet resting

During REM sleep
- deactivated PFC –> volition, insight, judgement and working memory decrease
- active amygdala and paralimbic cortex –> emotion and remote memory
- active brain stem (pontine tegmentum) –> activates cholingeric system, maintains cortical arousal, promotes visual imagery
- active parietal operculum –> visuospatial imagery

Question 7

AIM: Input source/origin

Answer 7

What information is being processed?

Waking
- primary input from external sensory stimuli

REM or daydreaming
- primary input from internal data sources (pseudo-sensory data produced by the brain stem) –> generation of fictive visual and motor data
- sensory input blocked (real-world data unavailable)
- motor output blocked (real-world action impossible)

NREM
- both external and internal input suppressed

Question 8

AIM: (Neuro)modulation

Answer 8

How is the information being processed?

• brain stem nuclei –> balance of neuromodulators, especially cholingeric and aminergic

Waking
- dominance of amingeric activity

REM
- dominance of cholingeric activity

NREM
- low amingeric activity with even lower cholingeric levels

Question 9

AIM state space

Answer 9

Waking
- high A (activity)
- external I (input)
- high aminergic M (modulator) levels

NREM
- low A (activity)
- minimal external and internal I (input)
- low aminergic and cholinergic M (modulator) levels

REM
- high A (activity)
- internal I (input)
- high cholinergic M (modulator) levels

Question 10

Sleep and learning

Answer 10

• conventional view: sleep processes participate in the consolidation of memory traces

Consolidation = process during which memory traces can be reactivated, analysed and gradually incorporated into long-term memory

procedural memory = comprises memories on skills or problem-solving (know how), nonclarative memory
declarative memory = accessible and conscious memories (knowing that)

Dual processing hypothesis
- effect of sleep on memory processing –> task-dependent
- prodecural branch linked to REM
- declarative branch linked to NREM

Question 11

Reorganisation of memory during sleep

Answer 11

schema = mental framework for the organisation and understanding of information
- enables the extraction of rules or general concepts on the meta-level

schema formation = extraction of rules
- rules can then be generalised to novel situations
- mainly during slow wave sleep

schema integration = integration of recent and remote memories, relational memory, and emergence of false memories
- mainly during slow wave sleep

schema disintegration = process of disbanding existing schemas to allow ‘outside the box thinking’ and creativity
- mainly during REM sleep