4.1 What is Consciousness?

• Consciousness: our awareness of internal and external stimuli.

  • Awareness of internal stimuli includes feeling pain, hunger, thirst, sleepiness, and being aware of our thoughts and emotions.

  • Awareness of external stimuli includes seeing the light from the sun, feeling the warmth of a room, and hearing the voice of a friend.

  • Sleep: a state characterized by relatively low levels of physical activity and reduced sensory awareness

  • Wakefulness: as state characterized by high levels of sensory awareness, thought, and behavior.

Biological Rhythms

• Biological rhythms: internal rhythms of biological activity (ie menstruation).

• Circadian rhythm: a biological rhythm that takes place over a period of about 24 hours (ie the sleep-wake cycle)

• Suprachiasmatic nucleus (SCN): the area of the hypothalamus the brain’s clock mechanism is located in

  • The axons of light-sensitive neurons in the retina provide information to the SCN based on tBhe amount of light present, allowing this internal clock to be synchronized with the outside world

Problems with Circadian Rhythms

• Disruptions of normal sleep

  • A person’s circadian clock gets out of synchrony with the external environment.

  • Jet lag: a collection of symptoms that results from the mismatch between our internal circadian cycles and our environment.

    • These symptoms include fatigue, sluggishness, irritability, and insomnia

  • Rotating shift work: a work schedule that changes from early to late on a daily or weekly basis.

    • The individual’s schedule changes so frequently that it becomes difficult to maintain a normal circadian rhythm.

    • This often results in sleeping problems, and can lead to signs of depression and anxiety.

• Insufficient sleep

  • Sleep debt: when an individual does not get sufficient sleep on a chronic basis.

    • The consequences of sleep debt include decreased levels of alertness and mental efficiency.

4.2 Sleep and Why We Sleep

What is Sleep?

• Homeostatic regulation of sleep is evidenced by sleep rebound following sleep deprivation.

• Sleep rebound: when a sleep-deprived individual tends to take a shorter time to fall asleep during subsequent opportunities for sleep.

• Sleep involves the secretion and regulation of a number of hormones from several endocrine glands including: melatonin, follicle stimulating hormone (FSH), luteinizing hormone (LH), and growth hormone

  • The pineal gland releases melatonin during sleep.

    • Melatonin: involved in the regulation of various biological rhythms and the immune system

  • The pituitary gland secretes FSH, LH, and growth hormones

    • FSH and LH: important in regulating the reproductive system

    • Growth hormones: important for in physical growth, maturation, and other metabolic processes

Why Do We Sleep?

• Adaptive Function

  • Sleep is essential to restore resources that are expended during the day.

  • Our sleep patterns evolved as an adaptive response to predatory risks, which increases in the dark.

• Cognitive Function

  • Slow-wave sleep after learning a new task can improve resultant performance on that task and is essential for effective memory formation

4.3 Stages of Sleep

• Sleep is divided into two phases: REM sleep and non-REM (NREM) sleep.

• Rapid eye movement (REM) sleep: darting movements of the eyes under closed eyelids.

  • Brain waves during REM sleep are very similar to brain waves during wakefulness.

• non-REM (NREM)sleep: subdivided into four stages distinguished from each other and from wakefulness by patterns of brain waves.

• The first four stages of sleep are NREM sleep, while the fifth and final stage of sleep is REM sleep.

NREM Stages of Sleep

• Stage 1 sleep: a transitional phase that occurs between wakefulness and sleep, the period during which we drift off to sleep.

  • There’s a decrease in the rates of respiration and heartbeat, as well as overall muscle tension and core body temperature.

• Stage 2 sleep: the body goes into a state of deep relaxation.

  • Sleep spindles and K-complexes appear

    • Sleep spindle: a rapid burst of higher frequency brain waves that may be important for learning and memory

    • K-complex: a very high amplitude pattern of brain activity that may occur in response to environmental stimuli.

• Stage 3 and 4 sleep: deep sleep or slow-wave sleep

  • An individual’s heart rate and respiration slow dramatically.

REM Sleep

• The period of sleep in which dreaming occurs.

• It’s associated with the paralysis of muscle systems in the body, except those responsible for circulation and respiration.

  • No movement of voluntary muscles occurs during REM sleep.

• REM rebound: when people are deprived of REM sleep and then allowed to sleep without disturbance, they spend more time in REM sleep to make up for lost time.

Dreams

• By analyzing dreams, Freud thought people could increase self-awareness and gain valuable insight to help them deal with their problems. Freud differentiated between the manifest content and the latent content of dreams.

  • Manifest content: the actual content, or storyline, of a dream.

  • Latent content: the hidden meaning of a dream.

• Carl Jung believed that dreams allowed us to tap into the collective unconscious.

  • Collective unconscious: a theoretical repository of information Jung believed to be shared by everyone.

    • Certain symbols in dreams reflect universal archetypes with meanings that are similar for all people regardless of culture or location.

• Rosalind Cartwright believes that dreams simply reflect life events that are important to the dreamer.

  • Cartwright’s ideas about dreaming have found empirical support.

• Hobson suggests that dreaming may represent a state of protoconsciousness.

  • Dreaming involves constructing a virtual reality in our heads that we may use to help us during wakefulness.

  • Lucid dreams: dreams in which certain aspects of wakefulness are maintained during a dream state.

    • A person becomes aware of the fact that they’re dreaming and can control the dream’s content

4.4 Sleep Problems and Disorders

• Insomnia: a consistent difficulty in falling or staying asleep

  • People suffering from insomnia often experience increased levels of anxiety about their inability to fall asleep. This becomes a self-perpetuating cycle because increased anxiety leads to increased arousal, and higher levels of arousal makes falling asleep even more unlikely.

  • Chronic insomnia is almost always associated with feeling overtired and may be associated with symptoms of depression.

  • Some forms of psychotherapy, such as cognitive-behavioral therapy, can help treat insomnia.

    • Cognitive-behavioral therapy: a type of psychotherapy that focuses on cognitive processes and problem behaviors.

• Parasomnia: one of a group of sleep disorders in which unwanted, disruptive motor activity and/or experiences during sleep play a role.

  • Parasomnias can occur in either REM or NREM phases of sleep.

  • Sleepwalking: the sleeper engages in relatively complex behaviors ranging from wandering about to driving an automobile.

    • They often have their eyes open, but aren’t responsive to attempts to communicate with them.

    • Sleepwalking often occurs during slow-wave sleep, but it can occur at any time during a sleep period in some affected individuals

  • REM Sleep Behavior Disorder (RBD): occurs when the muscle paralysis associated with the REM sleep phase does not occur.

    • Individuals who suffer from RBD have high levels of physical activity during REM sleep, especially during disturbing dreams (kicking, punching, scratching, yelling, etc)

      • These types of behaviors disrupt sleep, but affected individuals have no memories of these behaviors.

  • Restless leg syndrome: uncomfortable sensations in the legs during periods of inactivity or when trying to fall asleep.

    • This discomfort is relieved by voluntarily moving the legs, which contributes to difficulty in falling or staying asleep.

  • Night terrors: a sense of panic that’s often followed by screams and attempts to escape from the immediate environment

    • Individuals suffering from night terrors appear to be awake but they have no memories of the events that occurred, and attempts to console them are ineffective.

    • Individuals suffering from night terrors will fall back asleep again within a short time.

    • Night terrors occur during the NREM phase of sleep

• Sleep Apnea: episodes during which a sleeper’s breathing stops.

  • Individuals suffering from sleep apnea may not be aware of these disruptions, but they experience increased levels of fatigue.

  • It’s much more common in overweight people and often associated with loud snoring.

  • There are two types of sleep apnea: obstructive sleep apnea and central sleep apnea.

    • Obstructive sleep apnea: occurs when an individual’s airway becomes blocked during sleep, and air is prevented from entering the lungs.

    • Central sleep apnea: disruption in signals sent from the brain that regulate breathing cause periods of interrupted breathing

  • Sudden Infant Death Syndrome (SIDS): an infant stops breathing during sleep and dies.

• Narcolepsy: when an individual can’t resist falling asleep at inopportune times.

  • These sleep episodes are often associated with cataplexy, which is a lack of muscle tone or muscle weakness, and in some cases involves complete paralysis of the voluntary muscles.

  • Narcoleptic episodes are often triggered by states of heightened arousal or stress.

4.5 Substance Use and Abuse

Substance Use Disorders

• A person who has a substance use disorder often uses more of the substance than they originally intended to and continues to use that substance despite experiencing significant adverse consequences.

  • In individuals diagnosed with a substance use disorder, there is a compulsive pattern of drug use that is often associated with both physical and psychological dependence.

    • Physical dependence: changes in normal bodily functions—the user will experience withdrawal from the drug upon cessation of use.

      • Drug withdrawal includes a variety of negative symptoms experienced when drug use is discontinued. These symptoms are usually the opposite of the effects of the drug.

    • Psychological dependence: an individual has an emotional need for the drug and may use the drug to relieve psychological distress.

      • Tolerance: linked to physiological dependence, and occurs when a person requires more and more drug to achieve effects previously experienced at lower doses.

        • It can cause the user to increase the amount of drug used to a dangerous level (overdose and death).

Drug Categories

• Alcohol and other depressants

  • Alcohol: in a class of psychoactive drugs known as depressants

    • Low doses: feelings of euphoria.

    • High doses: feeling sedated.

    • Alcohol is associated with decreases in reaction time and visual acuity, lowered levels of alertness, and reduction in behavioral control.

  • Depressant: a drug that tends to suppress central nervous system activity.

  • Constant central nervous system depressants, such as alcohol, can cause physical dependence upon the substance and the user will exhibit signs of tolerance and withdrawal.

    • The abuse potential of central nervous system depressants is high.

• Stimulants

  • Stimulants: drugs that tend to increase overall levels of neural activity.

  • Many of these drugs act as agonists of the dopamine neurotransmitter system.

    • Dopamine activity is often associated with reward and craving, so drugs that affect dopamine neurotransmission often have abuse liability.

  • Examples: cocaine, amphetamines, cathinones, MDMA, nicotine, and caffeine

• Opioids

  • Opioid: one category of drugs that includes heroin, morphine, methadone, and codeine.

  • Opioids have analgesic properties (they decrease pain).

  • Humans have an endogenous opioid neurotransmitter system—the body makes small quantities of opioid compounds that bind to opioid receptors reducing pain and producing euphoria.

    • Opioid drugs, which mimic this endogenous painkilling mechanism, have an extremely high potential for abuse.

  • Opiates: natural opioids; derivatives of opium, which is a naturally occurring compound found in the poppy plant.

• Hallucinogens

  • Hallucinogen: one of class of drugs that results in profound alterations in sensory and perceptual experiences

  • It’s common for these types of drugs to cause hallucinations of body sensations and a skewed perception of the passage of time.

  • Hallucinogens are varied in terms of the neurotransmitter systems they affect.

4.6 Other States of Consciousness

Hypnosis

• Hypnosis: a state of extreme self-focus and attention in which minimal attention is given to external stimuli.

• Individuals undergoing hypnosis usually have clear memories of the hypnotic experience and are in control of their own behaviors.

• Hypnosis may be useful in enhancing memory or a skill, but such enhancements are very modest in nature.

• Components of bringing an individual into a state of hypnosis

  • The participant is guided to focus on one thing

  • The participant is made comfortable and is directed to be relaxed and sleepy.

  • The participant is told to be open to the process of hypnosis, trust the hypnotist and let go.

  • The participant is encouraged to use their imagination.

Meditation

• Meditation: the act of focusing on a single target to increase awareness of the moment.

• The central feature of all meditation is clearing the mind in order to achieve a state of relaxed awareness and focus.

• Meditative techniques have their roots in religious practices, but their use has expanded to alternative medicine.