Stages of Sleep + Length + Types of Waves + Features
Awake: alpha at rest (8-12/s), Beta alert (13+/s)
REM (Rapid Eye Movement) 5-6 times:
- Found as biologically critical from REM deprivation studies –> many intense REM bounce-backs
Non-REM (NREM) Sleep: short thought-like repetitive dreams about everyday tasks,
Circadian Rhythm + Free Running Rhythm + Effects of Disruption
Circadian Rhythms/Brain’s Biological Clock: scheduled by environmental cues alertness, changes in biological processes including body temperature, brain waves, drowsiness & hormones releases. Melatonin is key to regulating circadian rhythms
Free Running Rhythm: rhythm even when not exposed to environmental cues, shows that circadian rhythm+sleep is hardwired into biological system
Disruption disturbs sleep and increases the risk of injuries, fatal accidents, and health problems, including obesity, diabetes, and heart disease.
Recuperation vs Adaptation Theories
Recuperation Theories of Sleep: sleep restores homeostasis, a constant state of being (energy levels, repair, fighting infection), being awake disrupts this, long-term memory, problem solving, insight, neural development & connectivity
Adaptation Theories of Sleep: no physiological reason, result of 24hr timing mechanism protection from accidents & predators conserving energy
Comparative Studies of Animals on Sleep
Serves a Physiological Function: not just to protect from predators
- Gazelles have shorter sleep to be more aware of flat open environment, Dolphin sleep with half brain awake
Not only for Higher Order Human Function: not just to release emotions or mental health
Needed for Survival, not in great amounts: less during mating, migration, short supply
No Strong Relationship between Sleep Length & body size, energy expenditure, body temp
- Relation with Food Chain: apex can sleep as long as it wants, herbivores sleep less
How Much Do We Need to Sleep?
Newborn 19hr, Student 9hr, Adult+Elders 7hr
Types of Sleep Loss + Feature Effects
Total Sleep Deprivation: skipping entire night’s sleep → efficiency to get to stage 3 sleep
- Next sleep regains most of stage 3, more slow wave sleep 6-8hr especially during naps, less stage 1&2, waking during stage 3 causes sleepiness except for REM
(Chronic) Sleep Restriction: less sleep normal or optimal → less self awareness
- Moderate 3-4hr sleep led to 3 effects: (1)increase in sleepiness, falling asleep quickly if given the chance, (2) disturbances on written tests of mood, (3) poor vigilance
(Chronic) Sleep Disruption: repeated disruptions, length fine
Sleep Loss on Health
Physical Health: impaired immune system, increased heart rate (SNS activation), hormone dysregulation, inability to handle stress, weight gain, diabetes
Mental Health: cognitive impairment, memory lapses, hallucinations
Emotional Health: irritability, general anxiety, inability to handle stress , depression
Confound of Stress: lab studies are not under normal sleeping conditions
Ex. Experimental & control rat on a disk, results show sleep deprivation attributed to stress
Mortality: greater risk if sleep is less than 7hr or more than 8hr
Characteristics of REM Sleep
3 Common Beliefs about Dreaming
3 Theories on Function of REM + Criticisms
Criticism: lots of support but does not explain how antidepressants blocking REM don’t cause major issues
Effect of Depriving REM & NREM
Depriving REM Labs: constantly woken during REM → increased amount of REM sleep during study & subsequent nights
Depriving NREM Labs: constantly woken during deep sleep –> a sharp rebound of slow wave sleep during subsequent nights
4 Theories on Why We Dream
Lucid Dreams
Lucid Dreams: aware that one is dreaming & can affect the course of the dream (ex. Prearranged signals to communicate), cerebral cortex associated with self-perceptions and evaluating thoughts and feelings rev up with activity
3 Mysteries of REM
Sleep Disorders
Hypersomnia: disorders of excessive sleep or sleepiness
Kleine-Levin Syndrome: 15-21 hr/day
- Narcolepsy (few brain cells that produce orexin): severe daytime sleepiness at inappropriate times seconds-minutes immediately into REM, cataplexy-loss of muscle tone during wakefulness, sleep paralysis-can’t move as falling asleep or waking up, hypnagogic hallucinations-dreaming while awake
Insomnia: all disorders of initiating or maintaining sleep most are iatrogenic-physician created & stress, correlation with depression, chronic pain & conditions
- Sleep Apnea: blockage of airways during sleep, snoring gasping stop breathing higher risk of weight gain, fatigue, hearing loss, death, lack of oxygen, irregular heartbeat,
- Periodic Limb Movement Syndrome: limbs (usually legs) twitch or move during sleep
- Restless Leg Syndrome: tension or uneasiness in legs that prevents sleep
- Night Terrors: few mins of screaming, crying, perspiring, confused, wide-eyed
- Sleep Walking (somnambulist): walking while asleep, sleep deprived individuals more commonly (sexsomnia, sexual acts while asleep)
Psychoactive Drugs
Influence the subjective experience & behavior by acting on the central nervous system, contains chemicals similar to those found naturally in our brains that alter consciousness by changing chemical processes in neurons. Assumed to affect physiological functions & exogenous: outside of body rather than endogenous (insulin)/
Methods of administration and absorption
Ingestion: easy + safe, unpredictable effects (ex. Beer, edibles)
Injection: speedy + predictable effects, speedy effects+infection potential (intramuscularly, intravenously, subcutaneously)
Inhalation: speedy effects, unpredictable effects+damage to lungs
Absorption/Mucous Membranes: damages membranes
How Drugs Affect CNS
Neuron membranes diffuse throughout CNS to excite or inhibit
Binding + affecting a particular synaptic receptor, influences synthesis, transport, release, or deactivation of particular NT
Influencing chain of chemical reactions elicited in postsynaptic neurons by activation of receptors
Drug Metabolism & Elimination
Drug Metabolism: conversion of active drugs into non-active forms, usually by liver enzymes, so it can no longer pass through the blood brain barrier
Drug Excretion: elimination from the body
Tolerance vs Sensitization
Drug Tolerance: repeated exposures produce a diminished effect or requires an increased dose to maintain a constant effect through neural adaptation that counteracts the effect of drug
Drug Sensitization: repeated exposures produce a heightened drug effect or requires a smaller dose to maintain a constant effect
Note:
Cross-Tolerance: drug produces tolerance/sensitization to other drugs that acts by same mechanism
Tolerance/Sensitization develops to some effects of a drug but not others
Conditioned Compensatory Response: physiological changes that occur as a result of conditioned cues associated with a particular drug, increasing the tolerance for the drug. Less tolerant if unexpectedly stimulus occurs
Withdrawal
Withdrawal Syndrome: adverse physiological reaction due to sudden removal of a drug that has been used for a significant period of time
Opposite effects of drugs occurs when individuals are physically dependent on drug where neural adaptation is still strong & occurring
Severity depends on: type of drug, duration + degree of exposure, speed of drug’s removal
Classical Conditioning on Tolerance & Withdrawal (Hint Draw Design)
Association with environment with drug use, conditioning more tolerance when using drug in conditioned environment. Big injection kills more rats in new environment.
Withdrawal effects can be present without the drug itself, just by the environment cues. (See drawings)
Substance Use Disorder + Addiction
Substance use disorder: recurrent significant impairment or distress associated with one or more drugs
Addicts: habitual drug users who continue to use a drug despite its adverse effects & despite their repeated efforts to stop using
Mental set—beliefs and expectancies about the effects of drugs—the settings in which people take these drugs, and their cultural heritage and genetic endowment all play a part in accounting for the highs and lows of drug use
5 Models of Addiction + General Criticism