PSYC 444 Study Guide - Winter 2018, Comprehensive Midterm Notes - Rapid Eye Movement Sleep, Non-Rapid Eye Movement Sleep, Memory
11 Oct 2018
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PSYC 444
MIDTERM EXAM
STUDY GUIDE
Fall 2018
PSYC 444 – LECTURE 1
WHAT IS SLEEP?
Behavioral view: inactivity
Sleep scientist view: polysomnographic markers
Subjective experience: feeling of being asleep, dreaming; parasomnias
It is difficult to distinguish a sleeping person and a person in a coma as the physical indicators are the same.
• Must use electrodes and brain patterns to infer stage of sleep
• Even if not dreaming, there is the subjective experience of having slept; it is different from being in a coma or being knocked out
THEME: DYNAMIC BALANCE
Homeostasis: organism needs to maintain internal stability in face of environmental perturbations
Dynamic balance: system looks stable and unchanging but it is actually constantly adapting to changes in both its internal states and
environment
Themes: activity, cyclic, waking, amount and self-world
Organisms must sleep in order to survive, be cognitively available and to regenerate. However, this must be balanced with vigilance when
awake. Thus, demands from the world and bodily needs must be in a state of equilibrium.
WHO STUDIES SLEEP?
Psychologists, neurologists, neuroscientists, clinicians and philosophers
• Philosophers study sleep and consciousness
Every physiological or psychological function is related to sleep to some extent.
• However, despite ubiquity of sleep, there are very little resources available to the general population
• Very few are trained in sleep therapy, and sleeping pills are not a good solution
HISTORY OF SLEEP RESEARCH
As far as I ko, the oly reaso e eed to sleep that is really, really solid is eause e get sleepy” (DT Max)
• An experiment that kept rats awake demonstrated that without sleep, animals die
If sleep does’t sere a asolutely ital futio, it is the iggest istake the eolutioary proess has eer ade” (Alan Rechtschaffen)
• We are completely vulnerable while asleep. Thus, there must be an evolutionary reason for sleeping
There is no single accept theory on sleep
Homeostatic theory: life is energy-demanding, and sleep allows us to conserve energy
• Sleep is involved in thermoregulation
Cognitive theory: sleep is the price for brain plasticity
• Downscaling synaptic strength in sleep allows for more cognitive function in wake
• Sleep for memory consolidation and optimal emotion and attention functioning
BASIC NOTIONS
Sleep is ubiquitous
All animals sleep: Unicellular organisms, insects, amphibians, fish, birds and mammals
• Even unicellular organisms without a nervous system show patterns of rest
• Unclear whether plants have patterns of sleep
SLEEP AND CONSCIOUSNESS
It is difficult to define the relationship between sleep and consciousness
• Many taxonomies have been proposed
• What’s the differee etee soeoe asleep, uosious or oatose?
Main problem: definition of consciousness varies widely between researchers in the same domain, and especially between domains
THREE CLASSIC STATES OF CONSCIOUSNESS/AWARENESS
1. Wake
• Awareness of self and environment
• Fast reflexes
• Mental activity is spontaneous and intentional
2. Deep sleep
• Slow wave, delta, non-rapid-eye-movement (NREM) sleep
• Dreamless
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• No explicit awareness of self or environment (exceptions: sleepwalking)
• High threshold of reactivity to external stimuli: hard to wake someone up
• Simple mental activity (images, thoughts)
• Tendency towards amnesia: when asked what happened during sleep, typically do not remember or only has vague feeling
3. REM sleep/paradoxical sleep
• Awareness of dream environment and dream self. In some cases, awareness of sleeping self and physical environment (lucid
dreams)
• Relatively low threshold of awareness of external stimuli: easy to wake up
• Both spontaneous and intentional mental activity (within the dream)
Consciousness meter: defining and measuring consciousness
• Higher the complexity of neuronal connections, the more conscious
• May be awake but have low physiological arousal
Two dimensions: arousal and awareness
• Vegetative state: dissociation between two scales
• Minimally conscious state: some awareness
• Locked in syndrome: paralyzed but aware of self and world
o Unable to communicate or initiate movement, only blink
o Thus, eye-tracking used to communicate
o High arousal: mind and body are fine but there is absence of control
Patients asked to imagine a simple, repetitive mental activity, and the somatosensory cortex lights up
Despite these graphs being very reductionist and limited, they aid clinical research
NORMAL HUMAN SLEEP
Behavioral definition: reversible state of perceptual disengagement from and insensibility to the environment
• Typical taxonomy is very clinically oriented. This is not enough for more nuanced sleep research
• Definition is very vague, though the phenomenon very complex
CONTEMPORARY VIEW OF SLEEP
Sleep is an active and dynamic cyclical process
Many physiological and psychological functions (possibly all) depend on sleep
• Example: hormones, development, immune system, gene expression, neurogenesis, memory consolidation, emotion regulation
It is NOT just disengagement. The mind and body are doing many things that are not yet well understood
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