Psychology Chapter 13-14 PDF

**States of Consciousness** 13.1.01 Alertness **Consciousness** is an individual\'s awareness of the environment and themselves. Examples of altered states of consciousness from normal alertness include sleeping and dreaming. Multiple brain areas contribute to alertness. As Concept 4.3.01 introdu...

**States of Consciousness** 13.1.01 Alertness **Consciousness** is an individual\'s awareness of the environment and themselves. Examples of altered states of consciousness from normal alertness include sleeping and dreaming. Multiple brain areas contribute to alertness. As Concept 4.3.01 introduces, the reticular formation (RF) is a collection of neurons that spans the brainstem (Figure 13.1). Part of the RF, the ascending **reticular activating system** (RAS) projects to the prefrontal cortex, among other cortical areas, and is important in consciousness and wakefulness. Damage to the RAS can result in sleep or even a coma. **Figure 13.1** The reticular formation. [Dissociation](javascript:void(0)) is the separation of certain thoughts, behaviors, or memories from normal consciousness. For example, if lost in thought while driving, a person may dissociate and arrive at a destination unable to remember the drive. In severe cases, dissociation characterizes psychological disorders involving disruption to memory and/or identity (stemming from psychological causes) (see Concept 29.1.07). Consciousness has been described in the theories of notable historical figures in psychology. Wilhelm Wundt used introspection (ie, reporting conscious thoughts and sensations) to reveal the elements of consciousness. Another early psychologist, William James, asserted that consciousness continuously flows and is ever-changing, like a \"stream of thought.\" In addition, Sigmund Freud\'s psychoanalytic theory described [three levels of consciousness](javascript:void(0)): the unconscious (entirely beyond conscious awareness), the preconscious (just beneath conscious awareness), and the conscious mind. According to Freud, personality results from conflicts between the A diagram of a brain Description automatically generated Chapter 13: Consciousness and Sleep 76 conscious and unconscious mind (eg, one\'s sense of right and wrong conflicting with one\'s impulses) (see Lesson 26.1). 13.1.02 Sleep As Concept 13.1.01 introduces, one altered state of consciousness beyond normal wakefulness is sleep. The neural basis of sleep includes brainstem neurons, principally neurons in the pons, which play an important role in controlling sleep (Figure 13.2). Sleep is covered in more detail in Lesson 13.2. **Figure 13.2** The pons. The pons is also involved in dreaming, another altered state of consciousness. One of the theories that explains dreaming, the activation-synthesis hypothesis, states that dreams result from the brain\'s attempt to make sense of the random activity of the pons during sleep. The theories on dreaming are discussed further in Concept 13.2.03. **Stages of Sleep** 13.2.01 Sleep Cycles Sleep is broadly divided into **non-rapid eye movement** (NREM) sleep (stages N1-3) and **rapid eye movement** (REM). Sleep occurs in four to six 90-minute cycles each night, and the proportion of REM increases each sleep cycle. Figure 13.3 provides an overview of the sleep stages and cycles. The amount of time spent in each sleep stage differs over the course of a single night\'s sleep; a typical adult spends about 20%-25% of sleep time in REM sleep. Dreaming (see Concept 13.2.03) is most common during REM sleep but can occur in NREM stages as well. **Figure 13.3** Sleep stages and cycles. As Lesson 7.1 introduces, [electroencephalography](javascript:void(0)) (EEG) depicts waves of brain activity reflective of the various sleep and waking states (see Figure 13.4). Alpha and beta waves are high-frequency, low-amplitude waves characteristic of waking states. **Beta waves** have the highest frequency and are typical of an awake, alert state; **alpha waves** have more regularity and are indicative of an awake, relaxed state.  Chapter 13: Consciousness and Sleep 78 **Figure 13.4** Brain wave patterns. Stage 1 sleep (N1), or \"light sleep,\" is marked by **theta waves**. Sudden, jerking body movements occur when an individual first falls asleep and enters the N1 stage. During NREM sleep, respiration, heart rate, and body temperature gradually decrease. During stage 2 sleep (N2), theta waves still predominate but are interrupted by occasional sleep spindles (bursts of increases in frequency) and K-complexes (increases in wavelength). The deepest stage of NREM sleep is stage 3 (N3), slow-wave sleep. (Note: N3 reflects a consolidation of sleep stages 3 and 4 under the previous classification.) N3 is characterized by **delta waves**, which demonstrate the lowest frequency and highest amplitude observed during the sleep cycle. In contrast, REM sleep is characterized by brain activity resembling an alert state, high-frequency, low-amplitude waves similar to beta waves. Also known as paradoxical sleep, REM sleep is marked by rapid closed-eye movements, a low body temperature, and irregular respiration and heart rates. During typical REM sleep, muscle tone in the body is very relaxed, preventing the acting out of dreams that could result in injury. Exceptions to this near paralysis are the muscles controlling the eyes and the cardiopulmonary system. Sleep is critical to physical and mental health; sleep deprivation can have negative effects such as fatigue, depression, difficulty concentrating, and weight gain. In the **REM rebound effect**, individuals deprived of REM sleep for even one night experience more REM sleep than usual the next night. Because they spend more time in REM, their dreams are more vivid and of longer duration. Sleep-wake disorders are discussed in Concept 13.2.04. A screenshot of a screenshot of a computer Description automatically generated Chapter 13: Consciousness and Sleep 79 13.2.02 Circadian Rhythms **Circadian rhythms** are cycles in physiological activity (eg, hormone release) or behavior (eg, sleeping) that occur over 24-hour intervals. One example is the sleep-wake cycle, the alternating intervals of wakefulness and sleep. Circadian rhythms are regulated by the **suprachiasmatic nucleus** of the hypothalamus (SCN) and the [pineal gland](javascript:void(0)) (Figure 13.5). Photoreceptors in the retina project information about light levels to the SCN. When it is dark, the SCN causes the **pineal gland** to release **melatonin**, a hormone that causes sleepiness. When light levels are high, the SCN downregulates melatonin production. **Figure 13.5** SCN regulation of melatonin release. Most circadian rhythms, such as those involving blood pressure and core body temperature, occur in accordance with the timing of the sleep-wake cycle because they are synchronized through melatonin secretion (a light-dependent process). 13.2.03 Dreaming As Concept 13.2.01 introduces, dreaming is most often associated with REM sleep, particularly during the REM cycles that occur closer to waking. These cycles account for the visually intense dreams remembered after waking. Although less common, dreaming can also occur during NREM sleep. Several theories seek to explain why people dream. Concept 13.1.02 references the **activation-synthesis hypothesis**, which states that dreams result from the brain\'s attempt to make sense of the random activity of the [pons](javascript:void(0)) during sleep. Another theory, the **cognitive problem-solving theory**, argues that dreams are an opportunity for the brain to solve the problems people encounter while they are awake. In contrast, Sigmund Freud asserted that dreams are a type of [wish fulfillment](javascript:void(0)), in which people satisfy urges or desires they normally find unacceptable (eg, embarrassing). Freud believed that what the dream overtly seems to be about (manifest content) masks the unconscious drive or desire (latent content). For example, a student dreaming of a relaxing vacation (ie, manifest content) in which they do not have to take an anxiety-provoking exam (ie, latent content) is exhibiting wish fulfillment.  Chapter 13: Consciousness and Sleep 80 13.2.04 Sleep-Wake Disorders Sleep disorders are conditions marked by disturbed sleep that cause distress and/or impaired functioning (Figure 13.6). Sleep-wake disorders fall broadly into two categories: dyssomnias and parasomnias. **Dyssomnias** are more common in adults and involve interference with the quality or timing of sleep, such as difficulty falling or remaining asleep, or periods of excessive sleepiness during waking hours. Examples of dyssomnias include: **Narcolepsy**, which involves sudden, excessive sleepiness and uncontrollable episodes of falling asleep. These narcolepsy attacks often occur while one is experiencing strong emotions (eg, while laughing with friends). **Insomnia**, which is defined as difficulty falling and/or staying asleep. **Sleep apnea**, which results in fragmented (ie, disrupted) sleep because the individual\'s breathing repeatedly stops, causing them to wake up briefly. This can happen hundreds of times a night. Symptoms of sleep apnea include loud snoring, choking or gasping for air, and feeling tired on awakening. In contrast, **parasomnias** are more common in children and involve abnormal function of the nervous system during sleep, while falling asleep, or when waking up from sleep. One example is **somnambulism** (ie, sleepwalking). **Night terrors**, which is another example of a parasomnia, describes episodes of screaming, crying, or panic (ie, extreme distress) while still asleep. In contrast to nightmares, night terrors most often occur during NREM sleep and are not typically remembered. **Figure 13.6** Overview of characteristics associated with selected sleep disorders. **Consciousness-Altering Substances** 14.1.01 Consciousness-Altering Substances Psychoactive drugs or substances affect mood, perception, thinking, and/or behavior. Categories of psychoactive drugs include stimulants, depressants, and hallucinogens (Table 14.1). **Stimulants** are psychoactive drugs that increase activity in the central nervous system (CNS), resulting in an increased heart rate and feelings of well-being, energy, and alertness. Examples of stimulants include cocaine, nicotine, and caffeine. Amphetamines (eg, methamphetamine) are a class of stimulant that intensify mood and energy. Psychoactive drugs that decrease activity in the CNS are called **depressants**. Examples of depressants include alcohol and sedatives such as benzodiazepines (eg, Valium) and barbiturates. These drugs enhance the action of GABA, the brain's principal inhibitory neurotransmitter, resulting in drowsiness, impaired coordination, and reduced behavioral inhibition. **Opioids** (eg, morphine, heroin) are a class of depressants that lessen pain and produce a relaxed state by mimicking the actions of endorphins. As Concept 4.2.03 introduces, endorphins are opioids produced by the body that modulate pain, as well as contribute to elevated mood following exercise. After continued opioid use, the body produces fewer endorphins on its own, and the user experiences increased pain in the absence of the drug. Finally, **hallucinogens** are psychoactive drugs that cause distortions in perception in the absence of sensory input (eg, seeing colorful, distorted images that are not actually present in the environment). Examples of hallucinogens include lysergic acid diethylamide (LSD), psilocybin, and mescaline. Compared to drugs in other categories, hallucinogens have the lowest risk of dependence (dependence is described in Concept 14.2.01). **Table 14.1** Psychoactive drug categories, descriptions, and examples. **CNS** = central nervous system. Some drugs (eg, marijuana, MDMA) do not fit neatly into just one of these classifications because they have effects consistent with more than one category (eg, stimulant and hallucinogen **Problematic Substance Use** 14.2.01 Problematic Substance Use Psychoactive drugs or substances affect the central nervous system, resulting in changes in mood, thinking, and/or behavior. The long-term use of many psychoactive substances can cause psychological and physical dependence. **Psychological dependence** entails the belief that the substance is necessary for daily functioning (eg, a longtime smoker believes that they must smoke to feel relaxed). **Physical dependence** is the body\'s reliance on a substance (ie, tolerance and/or withdrawal). **Tolerance** occurs when increasing amounts of a substance must be consumed to feel the same level of initial effects. Tolerance involves neurochemical changes following repeated exposure to the drug (eg, modifications to synapses or neurotransmitter receptors). In addition, **withdrawal** occurs when physical (eg, headaches) and/or psychological (eg, anxiety) symptoms are experienced after stopping chronic substance use. Tolerance and withdrawal are contrasted in Figure 14.1. **Figure 14.1** Tolerance and withdrawal. A collage of a person with different stages of exposure Description automatically generated Chapter 14: Consciousness-Altering Substances 83 The long-term use of many psychoactive substances can also result in substance use disorders. **Substance use disorders** are characterized by the continuation of substance use despite significant negative effects, such as a disruption to health and/or functioning (eg, relationship problems, job loss). Substance use disorders may involve symptoms such as: Unsuccessful attempts to cut back or stop using the substance Strong craving for the substance Significant time spent on activities related to the substance (eg, obtaining or using the substance) Tolerance Withdrawal A region of the brain particularly involved in problematic substance use is the **mesolimbic reward pathway** (see Figure 14.2). This pathway contains the dopaminergic neurons of the midbrain\'s **ventral tegmental area** (VTA) (Concept 4.3.01) that project axons to the **nucleus accumbens**. The VTA also projects to different parts of the forebrain, including the lateral hypothalamus, amygdala, and prefrontal cortex. **Figure 14.2** Mesolimbic reward pathway. Rewarding stimuli (eg, food) activate this reward pathway, causing dopamine release. These areas are thought to be involved in motivation because behaviors leading to the stimulation of these neurons are reinforced. Drugs involved in substance-related disorders enhance the action of these dopaminergic neurons, and thus the use of these drugs is reinforced. Studies show that blocking the activity of dopamine disrupts the reward pathway and can decrease drug-taking and drug-seeking behavior.