Biological Psychology (Finals) PDF

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CHAPTER 4Genetics, Evolution, Development, and PlasticityGenetics and Evolution of Behavior Genes are chemicals that maintain their integrity from one generation to the next and influence the development of the individual. A dominant gene affects development regardless of whether a person has pairs ...

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CHAPTER 4 Genetics, Evolution, Development, and Plasticity Genetics and Evolution of Behavior 1. Genes are chemicals that maintain their integrity from one generation to the next and influence the development of the individual. A dominant gene affects development regardless of whether a person has pairs of that gene or only a single copy per cell. A recessive gene affects development only in the absence of the dominant gene. 104

synapses and myelin. Neuron proliferation varies among species mainly by the number of cell divisions. Migration depends on chemicals that guide immature neurons to their destinations. 117 2. In adult vertebrates, new neurons form only in a few parts of the brain. Adult humans form new olfactory receptors, but the brain develops new neurons only in the hippocampus and the basal ganglia, both of which are important for new learning. 119

2. Genes can change by mutations, microduplications, and microdeletions. 107

3. Growing axons find their way close to the right locations and then arrange themselves over a target area by following chemical gradients. 119

3. Gene expression can also change in a process called epigenetics, as chemicals activate or deactivate parts of chromosomes. Experiences can cause epigenetic changes, and in some cases an epigenetic change can influence the next generation. 107

4. After axons reach their targets based on chemical gradients, the postsynaptic cell adjusts the connections based on experience, accepting certain combinations of axons and rejecting others. This kind of competition among axons continues throughout life. 120

4. Most behavioral variations reflect the combined influences of genes and environmental factors. Heritability is an estimate of the amount of variation that is due

5. Initially, the nervous system develops more neurons than will actually survive. Axons of the sympathetic nervous system survive only if they reach a target cell that releases to them nerve growth factor. Otherwise, they die in a process called apoptosis. Apoptosis also occurs in the brain, but the factors controlling it are less well understood. Prenatal exposure to alcohol increases apoptosis. 122

to genetic variation as opposed to environmental variation. 108 5. Researchers estimate heritability of a human condition by comparing monozygotic and dizygotic twins and by comparing adopted children to their biological and adoptive parents. They also search for genes that are more common in people with one type of behavior than another. 108 6. Even if some behavior shows high heritability for a given population, a change in the environment might significantly alter the behavioral outcome. 109 7. Genes influence behavior directly by altering brain chemicals and indirectly by affecting other aspects of the body and therefore the way other people react to us. 110 8. The process of evolution through natural selection is a necessary outcome, given what we know about reproduction: Mutations sometimes occur in genes, and individuals with certain sets of genes reproduce more successfully than others do. 110 9. Evolution spreads the genes of the individuals who have reproduced the most. Therefore, if some characteristic is widespread within a population, it is reasonable to look for ways in which that characteristic is or has been adaptive. However, we need to evaluate the relative contributions of genetics and cultural influences. 112 Development of the Brain 1. In vertebrate embryos, the central nervous system begins as a tube surrounding a fluid-filled cavity. Developing neurons proliferate, migrate, differentiate, and develop

6. The developing brain is vulnerable to chemical insult. Many chemicals that produce only mild, temporary problems for adults can impair early brain development. 123 7. At an early stage of development, the cortex is sufficiently plastic that visual input can cause what would have been the auditory cortex to develop different properties and now respond visually. 124 8. Enriched experience leads to greater branching of axons and dendrites, partly because animals in enriched environments are more active than those in deprived environments. 125 9. Specialized experiences can alter brain development, especially early in life. For example, in people who are born blind, representation of touch and hearing expands in the brain areas usually reserved for vision. 127 10. Extensive practice of a skill expands the brain’s representation of sensory and motor information relevant to that skill. For example, the representation of fingers expands in people who regularly practice musical instruments. 127 11. Although controversy remains, several studies report that even brief practice of a skill, such as juggling, can produce measurable changes in brain anatomy. 129 12.Although expanded representation in the brain is ordinarily a good thing, it can be harmful if carried too far. Some musicians and others who use their hands many hours

each day develop brain changes that interfere with their ability to feel or use one finger independently of the others. 129 13. Compared to adults, adolescents tend to be impulsive and centered more on present pleasures than future prospects. In most cases, risky behaviors in adolescents probably reflect increased drive for excitement, more than lack of ability to inhibit impulses. 131 14. On average, people in old age show declining memory and reasoning, and shrinkage of certain brain areas. However, these averages do not apply to all individuals or all situations. On average, physically fit people tend to maintain their cognitive abilities. Many older people compensate for inefficiency of certain brain functions by recruiting activity in additional brain areas. 132 Plasticity after Brain Damage 1. Brain damage has many causes, including blows to the head, obstruction of blood flow to the brain, or a ruptured blood vessel in the brain. Strokes kill neurons largely by overexcitation. 136 2. During the first hours after an ischemic stroke, tissue plasminogen activator (tPA) can reduce cell loss by breaking up the blood clot. However, not many patients get treatment in time for tPA to be helpful. 137 3. Many procedures for reducing the effects of nervous system injury have shown promise with laboratory animals, but so far none of them have been reliably helpful with humans. One reason is that many of the treatments are effective only if administered promptly after nervous system damage. Also, many patients have additional health problems, not just the stroke or other damage. 137 4. When one brain area is damaged, other areas become less active than usual because of their loss of input. Stimulant drugs can help restore normal function of these undamaged areas. 138 5. After an area of the CNS loses its usual input, other axons begin to excite it as a result of either sprouting or denervation supersensitivity. The anatomical reorganization is helpful in some cases but not always. 138 6. The phantom limb experience occurs because axons from another body part invade the cortical area ordinarily devoted to sensation from the now lost body part. Stimulation of the other body part now produces sensation as if it had come from the amputated part. 140 7. Many individuals with brain damage are capable of more than they show because they avoid using skills that have become impaired or difficult. 141

CHAPTER 11 Emotional Behaviors What is Emotion? 1. Most attempts to define emotion include several aspects including cognition, feelings, and action. 352 2. The sympathetic nervous system readies the body for emergency fight-or-flight activities. 352 3. According to the James-Lange theory, the feeling aspect of an emotion results from feedback from actions of the muscles and organs. 353 4. People with impaired autonomic responses continue to report emotional experiences, although the feeling aspect is weaker than before. 353 5. Bodily sensations can strengthen emotional feelings. 354 6. The various components of an emotion do not always occur together. Also, apparently no emotion corresponds to activity in a single brain area. For these and other reasons, many psychologists are uncertain that emotion is a natural category. 354 7. People recognize others’ emotions partly on the basis of facial expressions, but the recognition depends partly on culture and experience. The research on facial expressions does not conclusively demonstrate a small number of basic emotions. An alternative view is that emotions vary along two or more dimensions. 356 8. Activation of the frontal and temporal areas of the left hemisphere is associated with approach and the behavioral activation system. The corresponding areas of the right hemisphere are associated with withdrawal, decreased activity, and the behavioral inhibition system. 357 9. Damage to the ventromedial prefrontal cortex in many cases impairs the ability to anticipate emotional consequences, alters responses to moral dilemmas, and impairs decision making. 359

Attack and Escape Behaviors 1. An experience that gradually provokes an attack leaves an individual more ready than usual to attack again. 362 2. Aggressive behavior relates to both genetic and environmental influences. Most evidence supports the hypothesis that a gene decreasing the activity of monoamine oxidase A increases aggressive behavior mainly among people who had abusive experiences in childhood. 363

3. Testosterone increases the probability of aggressive or assertive behavior, and cortisol decreases it. 363 4. Researchers measure enhancement of the startle reflex as an indication of anxiety or learned fears. 365 5. The amygdala is critical for increasing or decreasing the startle reflex. It also mediates learned fears. 366 6. According to studies using fMRI, the human amygdala responds strongly to fear stimuli and other stimuli that evoke strong emotional processing. It responds most strongly when the processing is effortful. 367

6. Because stress causes release of cytokines, it can also lead to lethargy and other symptoms that resemble those of illness. 378 7. The high cortisol levels associated with prolonged stress damages cells in the hippocampus, thereby impairing memory. 379 8. People vary in their resilience to stress, based on genetics, social support, and previous experiences. 379

7. People with damage to the amygdala fail to focus their attention on stimuli with important emotional content. 369 8. Damage to the amygdala impairs recognition of fear expressions largely because of lack of attention to the eyes. 370 9. Both genetics and experience can predispose people to anxiety disorders. 371 10. People with a smaller than average hippocampus have an increased probability of developing post-traumatic stress disorder. 372 11. Anti-anxiety drugs decrease fear by facilitating the binding of the neurotransmitter GABA to the GABAA receptors. 372

Stress and Health 1. Hans Selye introduced the idea of the general adaptation syndrome, which is the way the body responds to all kinds of illness and stress. 376 2. Stress is difficult to define. Because people apply the term to a wide range of major and minor experiences, research results about stress are highly variable. 376 3. Stress immediately activates the sympathetic nervous system and more slowly activates the hypothalamuspituitary-adrenal cortex axis. The adrenal cortex releases cortisol, which increases metabolism. 377 4. Although brief stress enhances the immune response and facilitates memory formation, prolonged stress drains the body of the resources it needs for other purposes. 377 5. Stress activates the immune system, helping to fight viruses and bacteria. The immune system releases cytokines, which stimulate the hypothalamus by releasing prostaglandins, which cross the blood–brain barrier. The hypothalamus reacts by activities to combat illness, including sleepiness, fever, and loss of appetite and energy. 378

CHAPTER 14 Psychological Disorders Substance Abuse 1. A drug that increases activity at a synapse is an agonist; one that decreases activity is an antagonist. Drugs act in many ways, varying in their affinity (tendency to bind to a receptor) and efficacy (tendency to activate it). 460 2. Predispositions to alcohol or drug abuse arise from genetics, prenatal environment, and later environment. Early- onset alcoholism reflects a stronger genetic predisposition than does later-onset alcoholism. 460 3. People who drink alcohol with relatively little sign of intoxication are more likely than other people to develop alcohol abuse. 461 4. Reinforcing brain stimulation, reinforcing experiences, and stimulant drugs increase the activity of axons that release dopamine in the nucleus accumbens. 462 5. For abused drugs other than stimulants, the amount of dopamine release does not correlate well with plea- sure or addiction, and blocking dopamine synapses has little effect on opiate use. Evidently dopamine is not as essential to addiction as researchers previously believed. 463 6. Repeated use of cocaine decreases the response of the nucleus accumbens to all pleasant experiences, but increases attention to cues reminding the individual of cocaine. 464 7. During abstinence from cocaine, glutamate synapses in the nucleus accumbens become more responsive to cocaine-related cues. That increased sensitivity increases cue-induced cravings for cocaine. 464 8. Repeated use of a drug leads to tolerance (decreased response) and withdrawal (unpleasant sensations during

abstention). 464 9. Several drugs including Antabuse and methadone help some people decrease their use of alcohol or opiates. 465 Mood Disorders 1. People with major depression find that almost nothing makes them happy. In most cases, depression occurs as a series of episodes. 468 2. Depression has a genetic predisposition, but no one gene has a strong effect by itself. Stress can provoke depression by activating the immune system. 469 3. Depression is associated with decreased activity in the left hemisphere of the cortex. 470 4. Several kinds of antidepressant drugs are in wide use. Tricyclics block reuptake of serotonin and catecholamines. SSRIs block reuptake of serotonin. SNRIs block reuptake of both serotonin and norepinephrine. MAOIs block an enzyme that breaks down catecholamines and serotonin. 470 5. Antidepressants probably do not produce their benefits simply by increasing synaptic levels of serotonin or any other transmitter. Ordinarily they affect synapses quickly but the mood benefits develop over weeks. 471 6. One hypothesis is that antidepressants exert their effects by promoting development of new neurons in the hippocampus. New neurons facilitate new learning that competes with old, unpleasant thoughts. 471 7. Most people do not respond quickly to antidepressant drugs, and part of the apparent benefit may be due to a placebo effect or the passage of time. 472 8. Psychotherapy is about as effective as antidepressants. Psychotherapy is more likely than antidepressant drugs to produce long-lasting benefits. 473 9. Other therapies for depression include exercise, electroconvulsive therapy, altered sleep patterns, and deep brain stimulation. 473 10. Exposure to bright lights is an effective, inexpensive treatment not only for seasonal affective disorder, but also for other major depression. 475 11. People with bipolar disorder alternate between depression and mania. Effective therapies include lithium salts and certain anticonvulsant drugs. A consistent sleep schedule is also recommended. 476 Schizophrenia 1. Positive symptoms of schizophrenia (behaviors that are not present in most other people) include hallucinations, delusions, inappropriate emotions, bizarre behaviors, and thought disorder. 480

2. Negative symptoms (normal behaviors absent that should be present) include deficits of social interaction, emotional expression, and speech. 480 3. Before diagnosing someone with schizophrenia, a therapist needs to rule out brain damage, drug abuse, and other conditions that could produce similar symptoms. 481 4. Studies of twins and adopted children imply a genetic predisposition to schizophrenia. However, the adoption studies do not distinguish between the roles of genetics and prenatal environment. 482 5. Researchers have identified many genes associated with schizophrenia, but no common gene increases the risk by much. A promising hypothesis is that schizophrenia results from new mutations or microdeletions of any of the hundreds of genes that are important for brain development. 483 6. According to the neurodevelopmental hypothesis, either genes or difficulties early in life, often before birth, impair brain development in ways that increase vulnerability to later insults and predispose to behavioral abnormalities beginning in early adulthood. 483 7. Many people with schizophrenia show mild abnormalities of brain development, especially in the temporal and frontal lobes. They also show cognitive deficits that make sense if their frontal and temporal lobes are less than fully functional. 484 8. Contrary to what psychiatrists used to believe, most people with schizophrenia do not continue deteriorating throughout life. Some recover, some remain troubled throughout life, and some alternate between remission and relapse. Although the brain shows abnormalities during the first episode of schizophrenia, most people show little or no increase in those abnormalities as time passes. 485 9. Parts of the prefrontal cortex are very slow to mature. It is plausible that early disruption of those areas might produce behavioral symptoms that manifest as schizophrenia in young adults. 485 10. According to the dopamine hypothesis, schizophrenia is due to excess dopamine activity. Drugs that block dopamine synapses reduce the positive symptoms of schizophrenia, and drugs that increase dopamine activity induce the positive symptoms. 486 11. Prolonged use of antipsychotic drugs may produce tardive dyskinesia, a movement disorder. Second generation antipsychotic drugs reduce the risk of tardive dyskinesia. 487 12. According to the glutamate hypothesis, part of the problem is deficient glutamate activity. Phencyclidine, which blocks NMDA glutamate synapses, produces both positive and negative symptoms of schizophrenia, especially in people predisposed to schizophrenia. 488

Autism 1. Autism spectrum disorder is diagnosed more often now than in the past. The severity of symptoms varies greatly. 492 2. Primary symptoms include a deficiency of social behavior and communication, including nonverbal communication. Many individuals also have repetitive stereotyped behaviors. 492 3. No one gene is responsible for this condition. In some cases, it relates to new mutations or microdeletions, including one mutation to a mitochondrial gene. 493 4. Difficulties in the prenatal environment also contribute. Some cases result because the mother during pregnancy produced certain antibodies that attack brain proteins. Consuming folic acid decreases the probability of having an autistic child. 493 5. Behavioral treatments are the only effective approach to treating social and communicative deficits. Many parents try fad treatments of doubtful effectiveness. 494 CHAPTER 10 Reproductive Behaviors Sex and Hormones 1. Male and female behaviors differ because of sex hormones that activate particular genes. Also, certain genes on the X and Y chromosomes exert direct effects on brain development. 322 2. Organizing effects of a hormone, exerted during a sensitive period, produce relatively permanent alterations in anatomy and physiology. 324 3. In the absence of sex hormones, an infant mammal develops female-looking external genitals. The addition of testosterone shifts development toward the male pattern. Extra estradiol, within normal limits, does not determine whether the individual looks male or female. However, estradiol is essential for normal development of a female’s internal anatomy. 324 4. Many brain areas differ on average between males and females. The mechanisms behind these differences vary from one area to another. Consequently a given individual’s brain areas have a mosaic of male-...