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Chapter Outline (See related pages) The Neuroscience Perspective Introduction to Neuroscience Focus on interaction between behavior and organic functions Mind-body problem--relationship between physical and psychological
aspects Behavior Genetics Chromosomes contain genetic instructions More than 2,000 genes are on a single chromosome Behavior genetics examines genetic influence on behaviorDiathesis-stress model helpful in explaining most genetically
influenced disorders
Diathesis refers to constitutional predisposition Stress combined with diathesis results in abnormal behavior Clinical Genetic Studies
Genotype is individual combination of genes; phenotype
is individual combination of observable characteristicsFamily studies used to examine genetic influences
Index case is identified; examine other members
of family to determine if they have same disorderEvidence is only suggestive of genetic transmission
since family members share environments Twin studies compare twins
Monozygotic (MZ) twins develop from single fertilized
egg and have same genotypeDizygotic (DZ) twins develop from two eggs fertilized
by two sperm and have half their genes in commonCo-twins examined to determine how many are
concordant Environment is still an important influence since MZ
twins are raised more alike than DZ twins Adoption studies
Attempt to separate the effects of genetics and environmental
influences Mother-child adoption studies are easier to conduct Molecular Genetic Studies
Molecular genetic studies identify which genes are involved
in behavioral disorders Linkage analysis uses genetic markers as clue in locating
gene controlling disorder The Central Nervous System Nervous system is vast network extending from brain to
rest of bodyCentral nervous system (CNS) consists of brain and spinal
cord
Primarily responsible for storing and transmitting information If problem in CNS, then problem in behavior Neurons made up of several structural features (i.e.,
cell body, dendrites, axon, axon terminals, and myelin sheath)
Impulse from one neuron to the next neuron continues by neurotransmitter Firing is all-or-none response Some impulses stimulate the nerve to fire, some inhibit firing Neurotransmitters
Neurotransmitters are chemicals stored in vesicles After release, they travel across gap and connect with receptors,
as keys fit in locks During reuptake neurotransmitters are broken down
and transported back to the axon terminal Receptors can change
Decrease in number or sensitivity is called down-regulation Increase in number or sensitivity is called up-regulation Several neurotransmitters have been studied
Acetycholine--body muscles, sleep disorders, and Alzheimer's
disease Dopamine--motor behavior, reward, schizophrenia Enkephalins--act on opiate receptors GABA--inhibitory effect Norepinephrine--fight-or-flight response, alertness Serotonin--role in constraint, depression Drug treatment
Psychopharmacology studies drug treatment of psychological
disorders Many drugs target neurotransmitters by increasing or
suppressing action of neurotransmitter The Anatomy of the Brain
Cerebral cortex, sulci, gyri, longitudinal fissure, corpus
callosum, central sulcus, lateral sulcus; lobes (parietal, frontal,
temporal, occipital) thought to have differing functions Cross-section of brain reveals hypothalamus, limbic structures
(e.g., amygdala, hippocampus), thalamus, basal ganglia, cerebellum,
pons, medulla, brain stem, reticular activating system, and ventricles Structures associated with abnormal behaviors Measuring the Brain
Electroencephalography (EEG) measures general brain activity
by giving picture of brain's response to external stimuli Positron emission tomography (PET) and single photon
emission computer tomography (SPECT) measure brain metabolism
and functionComputerized tomography (CT) and magnetic resonance
imaging (MRI) measure brain structureEach technique has advantages and disadvantages Psychosurgery
Surgery designed to reduce abnormal behavior is called psychosurgery Psychosurgical techniques have been refined,--for example,
cingulotomy and stereotactic subcaudate tractotomy Psychosurgery has been used in treating severe obsessive-compulsive
disorder, depression, and pain Psychosurgery is very controversial and is usually the last
treatment resort Lateralization: Effects of Language and Emotion
Lateralization refers to differences between the two
hemispheresComplex cognitive processes involve both hemispheres, yet
different aspects are localized The Peripheral Nervous System: Somatic and Autonomic Peripheral nervous system is a network leading from CNS to body
Somatic nervous system senses and acts on external
worldAutonomic nervous system of special interest to abnormal
psychology Autonomic nervous system controls smooth muscles, glands,
and internal organs
Sympathetic division mobilizes body to meet emergenciesParasympathetic division slows down metabolism and
regulates organs so that they can rebuild energy supplyRelationship between divisions is complex, and they work
together The Endocrine System Endocrine system produces hormones and is involved
in many functionsHypothalamus controls endocrine system Hormones may be involved in specific psychological disorders
such as depression, bipolar disorder, eating disorders, and stress-related
disorders Evaluating the Neuroscience Perspective Biochemical abnormality may be result not cause of disorder Not all biological treatments are effective Ethical issues are raised involving treatment, symptom reduction
and its consequences Cannot consider biogenic and psychogenic causation as either/or