Chapter 4 States of Consciousness

Chapter 4: States of Consciousness 4.1 What is Consciousness?       Consciousness describes our awareness of internal and external stimuli. o Internal stimuli: pain, hunger, thirst, sleepiness, thoughts and emotions o External stimuli: seeing light from the sun, feeling warmth, hearing a friend’s voice Sleep is a state marked by relatively low levels of physical activity and reduced sensory awareness that is distinct from periods of rest that occur during wakefulness Wakefulness is characterized by high levels of sensory awareness, thought, and behavior Biological rhythms are internal rhythms of biological activity (ex. Women’s menstrual cycle) o The pattern of temperature fluctuation, which repeats every day, is one example of a circadian rhythm. It’s a biological rhythm that takes place over a period of about 24 hours. (ex. Sleep-wake cycle, heart rate, blood pressure, blood sugar, body temp) Some sort of biological clock? o In the brain, the hypothalamus, which lies above the pituitary gland, is a main center of homeostasis. Homeostasis is the tendency to maintain a balance, or optimal level, within a biological system.  The brain’s clock mechanism is located in an area of the hypothalamus known as the suprachiasmatic nucleus (SCN). The axons of lightsensitive neurons in the retina provide information to the SCN based on the amount of light present, allowing this internal clock to be synchronized with the outside world. One important regulator of sleep-wake cycles is the hormone melatonin. The pineal gland, an endocrine structure located inside the brain that releases melatonin, is thought to be involved in the regulation of various biological rhythms and of the immune system during sleep. o Its release is stimulated by darkness and inhibited by light. o Someone being a night owl and someone being a morning person—individual differences in circadian patterns of activity are known as a person’s chronotype.  Differ in sleep regulation—the brain’s control of switching between sleep and wakefulness as well as coordinating this cycle with the outside world Disruptions of Normal Sleep  Jet lag is a collection of symptoms that results from the mismatch between our internal circadian cycles and our environment. Symptoms: fatigue, sluggishness, irritability, and insomnia (consist difficulty in falling or staying asleep for at least three nights a week over a month’s time)  Rotating shift work refers to a work schedule that changes from early to late on a daily or weekly basis.  A person with a sleep debt does not get sufficient sleep on a chronic basis. Consequences: decreased levels of alertness and mental efficiency. o Newborns require the most sleep (between 12 and 18 hours a night) Lack of sleep can result in decreased mental alertness and cognitive function. Can result in depression-like symptoms. o Sleep deprivation is associated with obesity, increased blood pressure, increased levels of stress hormones, and reduced immune functioning. A meta-analysis is a study that combines the results of many related studies.   4.2 Sleep and Why We Sleep    We spend approximately one-third of our lives sleeping What is sleep? o Homeostatic regulation of sleep is evidenced by sleep rebound following sleep deprivation. Sleep rebound refers to the fact that a sleep-deprived individual will tend to take longer falling asleep during subsequent opportunities for sleep. o Sleep is characterized by certain patterns of activity of the brain that can be visualized using electroencephalography (EEG), and different phases of sleep can be differentiated using EEG as well. o Sleep-wake cycles are controlled by multiple brain areas acting in conjunction with one another.  Thalamus—regulate slow-wave sleep  Hypothalamus—contains the SCN  Pons—regulates rapid eye movement (REM) sleep o Secretion and regulation of hormones from several endocrine glands: melatonin, follicle stimulating hormone, luteinizing hormone, and growth hormone.  Pineal gland releases melatonin- regulation of various biological rhythms and the immune system  Pituitary gland secretes FSH and LH which are important in regulating the reproductive system  Pituitary gland also secretes GH which plays a role in physical growth and maturation as well as other metabolic processes. Why do we sleep? o Evolutionary psychology—a discipline that studies how universal patterns of behavior and cognitive processes have evolved over time as a result of natural selection.  Sleep is essential to restore resources that are expended during the day? Not the best hypothesis.  Our sleep patterns have evolved as an adaptive response to predatory risk, which increase in darkness. Thus we sleep in safe areas to reduce the chance of harm. Also not the best hypothesis.  Sleep is important for cognitive function and memory formation? 4.3 Stages of Sleep   Sleep is composed of several different stages that can be differentiated from one another by the patterns of brain wave activity that occur during each stage. Brain wave activity can be visualized using EEG. 2 general phases: o REM sleep  Rapid eye movement (REM) sleep is characterized by darting movements of the eyes under closed eyelids.  brain waves during REM sleep appear very similar to brain waves during wakefulness. o Non-REM sleep  Non-REM (NREM) sleep is subdivided into four stages: 1. Stage 1 sleep transitional phase that occurs between wakefulness and sleep (when we drift off to sleep); slowdown in rates of respiration and heartbeat; a marked decrease in both overall muscle tension and core body temperature a. Associated with both alpha and theta waves. Alpha waves are relatively low frequency, high amplitude patters of electrical activity that become synchronized (very relaxed, yet awake) b. Theta waves are even lower frequency, higher amplitude brain waves than alpha waves 2. Stage 2 sleepdeep relaxation; theta waves still dominate but are interrupted by brief bursts of activity known as sleep spindles. a. A sleep spindle is a rapid burst of higher frequency brain waves that may be important for learning and memory. b. K-complexes—very high amplitude pattern of brain activity that may in some cases occur in response to environmental stimuli. Serve as bridge to higher levels of arousal in response to what is going on in our environments. 3. Stage 3 & Stage 4 are often referred to as deep sleep or slow-wave sleep because these stages are characterized by low frequency, high amplitude delta waves. a. Individuals heart rate and respiration slow dramatically. Hard to wake someone from stage 3 and stage 4. b. Individuals who have increased levels of alpha brain wave activity during stage 3 and stage 4 often report that they do not feel refreshed upon waking, regardless of how long they slept. 4. Stage 4—deep sleep 5. REM sleep (rapid movements of the eyes)—brain waves are similar to those observed when a person is awake. Dreaming stage. Paralysis of muscle systems in the body—no movement of voluntary muscles occur a. Often referred to as a paradoxical sleep because of this combination of high brain activity and lack of muscle tone. b. Implicated in various aspects of learning and memory c. REM rebound d. Involved in emotional processing and regulation e. REM deprivation can be beneficial in some circumstances— can improve symptoms of people suffering from major depression, and many effective antidepressant medications suppress REM sleep  Dreams o Freud thought: people could increase self-awareness and gain valuable insight to help them deal with the problems they faced in their lives. Made distinctions between the manifest content and the latent content.  Manifest content- the actual content, or storyline, of a dream  Latent content- the hidden meaning of a dream o Carl Jung believed that dreams allowed us to tap into the collective unconscious a theoretical repository of information he believed to be shared by everyone. Certain symbols in dreams reflect universal archetypes with meanings similar for all people. o Rosalind Cartwright, a sleep and dreaming researcher, believes that dreams simply reflect life events that are important to the dreamer. o Can detect visual images that occur during dreaming by using fMRI for neural measurements of brain activity patterns. o John Hobson cites research on lucid dreams as an opportunity to better understand dreaming in general. Lucid dreams are in which certain aspects of wakefulness are maintained during a dream state. A person becomes aware of the fact that they are dreaming, and as such, they can control the dream’s content. 4.4 Sleep Problems and Disorders       Between 30% and 50% of the population suffers from a sleep disorder at some point in their lives. Insomnia o A consistent difficulty in falling or staying asleep. Experience long delays between the times that they go to bed and actually fall asleep. o The individual may wake up several times during the night and have difficulty going back to sleep o Most common sleep disorders; indicated by experiencing it at least three nights a week for at least one month’s time. o Treatment: limit use of stimulant drugs (caffeine) or increase the amount of physical exercise during the day; OTC or prescribed sleep medications o Cognitive-behavioral therapy is a type of psychotherapy that focuses on cognitive processes and problem behaviors. Treatment: stress management techniques and changes in problematic behaviors (more time awake in bed) Parasomnias o A parasomnia is one of a group of sleep disorders in which unwanted, disruptive motor activity and/or experiences during sleep play a role o Can occur in either REM or NREM phases o Ex. Sleepwalking, restless leg syndrome, and night terrors  Sleepwalking, or somnambulism, the sleeper engages in relatively complex behaviors ranging from wandering about to driving an automobile.  Sleepers often have their eyes open, but not responsive to attempts to communicate with them.  Can be treated with a variety of pharmacotherapies ranging from benzodiazepines to antidepressants REM sleep behavior disorder (RBD) o Occur 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. o Affected individuals have no memories that these behaviors have occurred. o Associated with neurodegenerative diseases such as Parkinson’s disease Restless leg syndrome o Uncomfortable sensations in the legs during periods of inactivity or when trying to fall asleep and relieved by moving the legs which contributes to difficulty in falling or staying asleep. Night terrors    o A sense of panic in the sufferer and are often accompanied by screams and attempts to escape from the immediate environment o Appear to be awake but they have no memories of the events that occurred and attempts to console them are ineffective. o Occur during NREM phase of sleep Sleep apnea o Defined by episodes during which a sleeper’s breathing stops o Episodes can last 10-20 seconds or longer o Experience increased levels of fatigue o Symptoms: snore loudly and/or stop breathing for extended periods of time while sleeping o More common in overweight people o 2 types:  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 o Most common treatment: A continuous positive airway pressure (CPAP) device includes a mask that fits over the sleeper’s nose and mouth, which is connected to a pump that pumps air into the person’s airways, forcing them to remain open. SIDs o In sudden infant death syndrome (SIDS) an infant stops breathing during sleep and dies. o Infants younger than 12 months are at risk. Boys have a greater risk than girls. o Risk factors: premature birth, smoking within the home, and hyperthermia. o Infants should sleep on backs when put down to sleep and their cribs should not contain any items that will pose suffocation threats Narcolepsy o Cannot resist falling asleep at inopportune times o The sleep episodes are often associated with cataplexy, which is a lack of muscle tone or muscle weakness o Often triggered by states of heightened arousal or stress. o Can interfere with the ability to perform one’s job or complete schoolwork and can result in significant harm and injury (car accident) o Highly heritable—passed down genetically in families o Associated with reduced levels of the signaling molecule hypocretin in some areas of the brain 4.5 Substance Use and Abuse   Drug use disorders are addictive disorders and the criteria for specific substance (drug) use disorders are described in DSM-5. The person uses more of the substance than they originally intended to and continues to use that substance despite experiencing significant adverse consequences. o Physical dependence involves changes in normal bodily functions of use. o Psychological dependence has an emotional, rather a physical, need for the drug and may use the drug to relieve psychological distress. Tolerance is linked to physiological dependence, and it occurs when a person requires more and more drug to achieve effects previously experienced at lower doses. o Drug withdrawal includes a variety of negative symptoms experienced when drug use is discontinued. (ex. Unpleasant arousal and agitation) Drug categories o The effects of all psychoactive drugs occur through their interactions with our endogenous neurotransmitter systems. o Drugs can act as agonists or antagonists of a given neurotransmitter system.  Agonist facilitates the activity of a neurotransmitter system, and antagonists impede neurotransmitter activity. o A depressant is a drug that tends to suppress central nervous system activity (ex. Ethanol- aka alcohol). They share in common their ability to serve as agonists of the gamma-Aminobutyric acid (GABA) neurotransmitter system. GABA has a quieting effect on the brain, and GABA agonists also have a quieting effect. These types of drugs are often prescribed to treat both anxiety and insomnia. o Stimulants are drugs that tend to increase overall levels of neural activity. Many act as agonists of dopamine (reward and craving). Ex. Cocaine, amphetamines, nicotine, and caffeine.  Crack is often more addictive than cocaine itself because it is smokable and reaches the brain very quickly. Less expensive and more accessible.  Amphetamines block the reuptake of dopamine in addition to simulating its release. Commonly prescribed to children with ADHD.  Methamphetamine is a type of amphetamine that can be made from ingredients that are readily available.  The cocaine, amphetamine, cathinone’s, and MDMA users seek a euphoric high, feelings of intense elation and pleasure.  Caffeine is another stimulant drug. Used to maintain increased levels of alertness and arousal. While caffeine may have some indirect effects on dopamine neurotransmission, its primary mechanism of action involves antagonizing adenosine activity.  Nicotine—highly addictive; exerts its effects through its interaction with acetylcholine receptors. Most commonly used in the form of tobacco products like cigarettes or chewing tobacco o Opioid is one of a category of drugs that includes heroin, morphine, methadone, and codeine. 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 mimic this painkiller mechanism and have extremely high potential for abuse.  Natural opioids, called opiates, are derivatives of opium, which is a naturally occurring compound found in the poppy plant.  Heroin has been a major opioid drug of abuse. The use of heroin is associated with an initial feeling of euphoria followed by periods of agitation. o Users often bear needle track marks on their arms and have an increased risk for contraction of both TB and HIV.  People experiencing opioid withdrawal may be given methadone to make withdrawal from the drug less difficult. Methadone is a synthetic opioid that is less euphorigenic than heroin and similar drugs. Methadone clinics help people who previously struggled with opioid addiction manage withdrawal symptoms through the use of methadone.  Codeine is an opioid with relatively low potency. Prescribed for minor pain and is available over-the-counter in some other countries. Has abuse potential. o A hallucinogen is one of a class of drugs that results in profound alterations in sensory and perceptual experiences. Users can experience vivid visual hallucinations.  Incredibly varied in terms of the neurotransmitter systems they affect. Mescaline and LSD are serotonin agonists and PCP and ketamine act as antagonists of the NMDA glutamate receptor. o Medical Marijuana legal in nearly half of the US and DC. Marijuana that is prescribed by a doctor for the treatment of a health condition. Ex. People undergoing chemo will be prescribed marijuana to stimulate their appetite and prevent excessive weight loss.  Federal laws still classify this as an illicit substance 4.6 Other States of Consciousness   Hypnosis is a state of extreme self-focus and attention in which minimal attention is given to external stimuli. o Used to draw out information believed to be buried deeply in someone’s memory - The participant is guided to focus on one thing, such as the hypnotist’s words or a ticking watch. - 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 hypnotists and let go. - The participant is encouraged to use his or her imagination. o Dissociation (dissociated state of consciousness) or as the performance of a social role (people’s behavior can be shaped by their expectations of how they should act in a given situation. Meditation is the act of focusing on a single target (such as the breath or a repeated sound) to increase awareness of the moment. o A meditative state, as shown by EEG recordings of newly-practicing meditators, is not an altered state of consciousness per se. o Can help reduce blood pressure, and if used in conjunction with more traditional treatments as a way to manage hypertension.