Psychology - Biological Bases of Behavior

Unit 2: Biological Bases of Behavior Reflex Arc: Signal is sent from a sensory organ to the spinal cord, which processes the information instead of passing it on to the brain Module 16: Sleep Patterns and Sleep Theories Sleep is the periodic, natural loss of consciousness — as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation. - Circadian Rhythm: Our bodies have an internal biological clock, roughly synchronized with the 24-hour cycle of night and day. - This circadian rhythm appears in our daily patterns of body temperature, arousal, sleeping, and waking. - Age and experiences can alter these patterns, resetting our biological clock. Sleep Stages: We cycle through four distinct sleep stages about every 90 minutes. The sleep cycle repeats itself about every 90 minutes for younger adults (with shorter, more frequent cycles for older adults). - NREM sleep: non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep. 1. NREM-1 sleep is the brief, near-waking sleep with irregular brain waves we enter (after leaving the alpha waves of being awake and relaxed); hallucinations (sensations such as falling or floating) may occur. a. Alpha waves: the relatively slow brain waves of a relaxed, awake state. b. Hallucinations: false sensory experiences, such as seeing something in the absence of an external visual stimulus. c. Hypnagogic sensations: bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep. 2. NREM-2 sleep, in which we spend about half our sleep time, with its characteristic sleep spindles (bursts of rhythmic brain wave activity). 3. NREM-3 sleep is deep sleep, in which large, slow delta waves are emitted. a. During a normal night’s sleep, NREM-3 sleep shortens and REM and NREM-2 sleep lengthens. b. Brain emits large, slow delta waves and you are hard to awaken. c. Delta waves: the large, slow brain waves associated with the deep sleep of NREM-3. - REM sleep: rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. 4. REM (rapid eye movement) sleep is described as a paradoxical sleep stage because of internal arousal but external calm (near paralysis). It includes most dreaming and lengthens as the night goes on. 5. Unlike NREM-1, during REM sleep your heart rate rises, your breathing becomes rapid and irregular, and every half-minute or so your closed eyes dart around in momentary bursts of activity. 6. These eye movements announce the beginning of a dream — often emotional, usually story-like, and richly hallucinatory. Dreams aren’t real, but REM sleep tricks your brain into responding as if you are actually watching a real scene. 7. During REM sleep, your brain’s motor cortex is active, but your brainstem blocks its messages. This leaves your muscles relaxed, so much so that, except for an occasional finger, toe, or facial twitch, you are essentially paralyzed. Moreover, you cannot easily be awakened. a. The body is internally aroused, with waking-like brain activity, yet asleep and externally calm. Biology — our circadian rhythm as well as our age and our body’s production of melatonin (influenced by the brain’s suprachiasmatic nucleus) — interacts with cultural expectations and individual behaviors to determine our sleeping and waking patterns. Bright light tweaks the circadian clock by activating light-sensitive retinal proteins. These proteins control the circadian clock by triggering signals to the brain’s suprachiasmatic nucleus (SCN) — a pair of grain-of-rice-sized, 10,000-cell clusters in the hypothalamus. - Suprachiasmatic nucleus (SCN): a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of sleepiness. Module 17: Sleep Deprivation, Sleep Disorders, and Dreams Sleep Disorders: Insomnia: persistent problems in either falling or staying asleep - Consequence: tiredness and increased risk of depression - The most common quick fixes are sleeping pills and alcohol which can aggravate the problem, reducing REM sleep - Quick fixes can lead to tolerance - Tolerance: a state in which increasing doses are needed to produce an effect Narcolepsy: a sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times - Narke = “numbness” and lepsis = “seizure” - Narcolepsy attacks can occur at the most inopportune times, often triggered by strong emotions Heritable Sleep Apnea: a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings - Apnea = “with no breath” - Target mostly adults - After an airless minute, decreased blood oxygen arouses them enough to snort in air for a few seconds. This process repeats hundreds of times each night, depriving them of slow-wave sleep. - Apnea sufferers do not recall these episodes. - Sleep apnea is associated with obesity - Symptoms: loud snoring, daytime sleepiness, irritability, high blood pressure (increases the risk of a stroke or heart attack) - Treatment: a mask-like device with an air pump that keeps the sleeper’s airway open Night Terrors: a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during NREM-3 sleep, within two or three hours of falling asleep, and are seldom remembered - Target mostly children - Symptoms: sit up, walk around, talk incoherently, experience doubled heart and breathing rates, appear terrified while asleep - Night terror sufferers recall little nothing the next morning - Unlike nightmares which typically occur during early morning REM sleep, night terrors usually occur during the first few hours of NREM-3 Sleepwalking and sleeptalking are childhood disorders that run in families - Occurs for about ⅓ of those with a sleepwalking fraternal twin and ½ of those with a sleepwalking identical twin (same for sleep talking) - Sleepwalking: - happens during NREM-3 sleep - Harmless - Sleepwalkers recall their sleepwalking the next morning - Young children who have the deepest and lengthiest NREM-3 sleep are the most likey to experience night terrors and sleepwalking - Sleeptalking: occurs during any sleep stage Dream: a sequence of images, emotions, and thoughts passing through a sleeping person’s mind Manifest Content: according to Freud, the symbolic, remembered story line of a dream (as distinct from its latent, or hidden, content) Latent Content: according to Freud, the underlying meaning of a dream (as distinct from its manifest content) Freud viewed a dream’s manifest content as a censored, symbolic version of its latent content the unconscious drives and wishes (often erotic) that would be threatening if expressed directly. REM Rebound: the tendency for REM sleep to increase following REM sleep deprivation - the causes and functions of REM sleep are deeply biological - REM sleep occurs in mammals Module 18: Psychoactive Drugs Psychoactive Drug: a chemical substance that alters perceptions and moods. Substance Use Disorder: a disorder characterized by continued substance craving and use despite significant life disruption and/or physical risk - Diminished Control & Social Functioning - Tolerance: the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug’s effect - Withdrawal: the discomfort and distress that follow discontinuing an addictive drug or behavior Types of Psychoactive Drugs Psychoactive drugs all do their work at the brain’s synapses, stimulating, inhibiting, or mimicking the activity of the brain’s own chemical messengers, the neurotransmitter 1. Depressants: drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions a. Alcohol is a depressant which acts as a disinhibitor (slows brain activity that controls judgment and inhibitions) i. Equal-opportunity drug: increases (disinhibits) helpful tendencies (i.e. drinkers leaving extravagant tips), increases harmful tendencies (i.e. sexual aggression) ii. Alcohol Use Disorder: (popularly known as alcoholism) alcohol use marked by tolerance, withdrawal, and a drive to continue problematic use 1. Shrinks the brain 2. Girls and young women can become addicted to alcohol more quickly than boys and young men do because they have less of a stomach enzyme that digests alcohol iii. Slowed neural processing iv. Memory disruption v. Reduced Self-awareness vi. Expectancy Effects 1. Expectations influence behavior 2. Expectations help explain why adolescents sometimes drink when they’re upset and alone. Solitary drinking actually does not boost mood, but it does increase the likelihood of developing a substance use disorder. b. Barbiturates: drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgment i. They can impair memory and judgment c. Opiates: opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety i. Opiates include heroin and also medically prescribed pain-relief narcotics, such as codeine, morphine, and methadone ii. As blissful pleasure replaces pain and anxiety, the user’s pupils constrict, breathing slows, and lethargy sets in iii. Those who become addicted to this short-term pleasure may pay a long-term price: a gnawing craving for another fix, a need for progressively larger doses (as tolerance develops), and the extreme discomfort of withdrawal. iv. When repeatedly flooded with an artificial opiate, the brain eventually stops producing endorphins, its own opiates. If the artificial opiate is then withdrawn, the brain will lack the normal level of these painkilling neurotransmitters. 2. Stimulants: drugs (such as caffeine, nicotine, and the more powerful cocaine, amphetamines, methamphetamine, and Ecstasy) that excite neural activity and speed up body functions a. People use stimulants to feel alert, lose weight, or boost mood or athletic performance b. Stimulants can also be addictive. Cutting off from the usual dose may crash into fatigue, headaches, irritability, and depression c. Nicotine: a stimulating and highly addictive psychoactive drug in tobacco i. Cigarettes, e-cigarettes, tobacco products ii. Nicotine will signal the central nervous system to release a flood of neurotransmitters. Epinephrine and norepinephrine will diminish appetite and boost alertness and mental efficiency. Dopamine and opioids will temporarily calm anxiety and reduce sensitivity to pain. d. Cocaine: a powerful and addictive stimulant derived from the coca plant; produces temporarily increased alertness and euphoria i. Cocaine is snorted, injected, or smoked. It enters the bloodstream quickly, producing a rush of euphoria that depletes the brain’s supply of the neurotransmitters dopamine, serotonin, and norepinephrine. Within the hour, a crash of agitated depression follows as the drug’s effect wears off. ii. Cocaine use leads to emotional disturbances, suspiciousness, convulsions, cardiac arrest, or respiratory failure iii. Cocaine’s psychological effects depend in part on the dosage and form consumed, but the situation and the user’s expectations and personality also play a role. Given a placebo, cocaine users who thought they were taking cocaine often had a cocaine-like experience e. Amphetamine: drugs, such as methamphetamine, that stimulate neural activity, causing accelerated body functions and associated energy and mood changes f. Methamphetamine: a powerfully addictive drug that stimulates the central nervous system, with accelerated body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels i. Triggers the release of the neurotransmitter dopamine, which stimulates brain cells that enhance energy and mood, leading to heightened energy and euphoria ii. Aftereffects: irritability, insomnia, hypertension, seizures, social isolation, depression, and occasional violent outbursts iii. Methamphetamine may reduce baseline dopamine levels, leaving the user with continuing depressed functioning g. Ecstasy (MDMA): a synthetic stimulant and mild hallucinogen. Produces euphoria and social intimacy, but with short-term health risks and longer-term harm to serotonin-producing neurons and to mood and cognition i. Ecstasy triggers dopamine release, but its major effect is releasing stored serotonin and blocking its reuptake, prolonging serotonin’s feel-good flood ii. Users experience high energy, emotional elevation, and connectedness with those around them (“I love everyone”) iii. Harmful consequence: dehydrating effect which can lead to overheating, increased blood pressure, and death iv. Long-term consequence: repeated leaching of brain serotonin can damage serotonin-producing neurons, leading to decreased output and increased risk of permanently depressed mood v. Ecstasy suppresses the immune system, impairs memory, slows thought, and disrupts sleep by interfering with serotonin’s control of the circadian clock 3. Hallucinogens: psychedelic (“mind-manifesting”) drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input. a. Near-death experience: an altered state of consciousness reported after a close brush with death (such as cardiac arrest); often similar to drug-induced hallucinations b. LSD: a powerful hallucinogenic drug; also known as acid (lysergic acid diethylamide) i. The emotions of an LSD (or acid) trip vary from euphoria to detachment to panic c. Marijuana i. THC: the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations ii. Consequences: agitation and hallucination iii. Amplifies sensitivity to colors, sounds, tastes, and smells iv. Marijuana vs. Alcohol 1. Similarities: a. Relaxes, disinhibits, and may produce a euphoric high b. Impairs motor coordination, perceptual skills, and reaction time necessary for safely operating an automobile or other machine 2. Differences: a. Body eliminates alcohol within hours b. THC lingers in the body for more than a week, which means that regular users experience less abrupt withdrawal and may achieve a high with smaller-than-usual drug amounts. This is the opposite of typical tolerance, in which repeat users need larger doses to feel the same effect. v. Marijuana Use: 1. alleviates chronic pain and chemotherapy-related nausea, 2. is not associated with tobacco-related cancers, such as lung cancer, 3. is predictive of increased risk of traffic accidents, chronic bronchitis, psychosis, social anxiety disorder, and suicidal thoughts, and 4. likely contributes to impaired attention, learning, and memory, and possibly to academic underachievement. Module 19: Understanding Consciousness & Hypnosis Consciousness: our subjective awareness of ourselves and our environment Our conscious awareness is one part of the dual processing of our two-track minds. Although much of our information processing is conscious, more is unconscious and automatic — outside our awareness. - William James: “stream of consciousness,” with each moment flowing into the next - a process that allows us to both consider the past, present, and future and to plan ahead in order to adapt our behavior to the current circumstances Hypnosis - Posthypnotic Suggestion: a suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized; used by some clinicians to help control undesired symptoms and behaviors Hypnosis as Divided Consciousness - Distinctive brain activity in frontal lobe attention systems accompany hypnosis. - Ernest Hilgard: Hypnosis involves a special dual-processing state of dissociation: a split between different levels of consciousness, which allows some thoughts and behaviors to occur simultaneously with others - Hilgard viewed hypnotic dissociation as a vivid form of everyday mind splits — similar to doodling while listening to a lecture or typing the end of a sentence while starting a conversation. - Another form of dual processing, selective attention, may also play a role in hypnotic pain relief. PET scans show that hypnosis reduces brain activity in a region that processes painful stimuli, but not in the sensory cortex, which receives the raw sensory input. - Hypnosis does not block sensory input, but it may block our attention to those stimuli.