copyright © allyn & bacon 2007 chapter 3 biopsychology and the foundations of neuroscience this...
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Copyright © Allyn & Bacon 2007
Chapter 3Chapter 3
Biopsychology and the Foundations of Neuroscience
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• ISBN: 0-131-73180-7
Copyright © Allyn & Bacon 2007
Some Brain Facts…Some Brain Facts…
It is about the size of grapefruit
3 pounds, pinkish-gray, wrinkled surface
100 billion nerve cells, sometimes with up to 10,000 connections to other cells
At birth the brain has extra nerve cells that die off; by adolescence that stabilizes and the total number is constant later on
There is some loss and gain through adulthood, but by age 70 we end up with over 98%
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What is Biopsychology?What is Biopsychology?
Biopsychology –The specialty in psychology that studies the interaction of biology, behavior, and the environment
Neuroscience – Interdisciplinary field that focuses on the brain and its role in psychological processes
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Evolution has fundamentally shaped psychological
processes because it favors genetic variations that
produce adaptive behavior
How Are Genes and How Are Genes and Behavior Linked?Behavior Linked?
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How Are Genes and How Are Genes and Behavior Linked?Behavior Linked?
Innate – Inborn; present at birth; part of the organism’s biological heritage
Evolution –The gradual process of biological change that occurs in a species as it adapts to its environment
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Evolution and Natural SelectionEvolution and Natural Selection
Natural selection –The driving force behind evolution, by which the environment “selects” the fittest organisms
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How Natural Selection WorksHow Natural Selection Works
Environmental pressureEnvironmental pressure(changes in the environment)(changes in the environment)
CompetitionCompetition(for resources)(for resources)
Selection of fittest phenotypeSelection of fittest phenotype(from among a variety of phenotypes)(from among a variety of phenotypes)
Reproductive successReproductive success(genotype corresponding to fittest (genotype corresponding to fittest
phenotypes passed to next generation)phenotypes passed to next generation)
Frequency of that genotype increasesFrequency of that genotype increases(in next generation)(in next generation)
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Genes and InheritanceGenes and Inheritance
Genotype – An organism’s genetic makeup
Phenotype –An organism’s observable physical characteristics
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Genes and InheritanceGenes and Inheritance
Mutations – Genetic variations, which occur randomly, especially during the recombination of chromosomes in sexual reproduction
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Chromosomes, Genes, and DNAChromosomes, Genes, and DNA
DNA (deoxyribonucleic acid)– A long, complex molecule that encodes genetic characteristics
Genes (they are like words in a sentence)–The functional units of a chromosomeComposed of nucleotides—they are like the
letters in words (A,G,T,C)
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Sex chromosomes –The X and Y chromosomes that determine our physical sex characteristics
Chromosomes, Genes, and DNAChromosomes, Genes, and DNA
Chromosomes (like a string of words; they include punctuation and timing)– Tightly coiled threadlike structures along which the genes are organized
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Genetic Explanations for Genetic Explanations for Psychological ProcessesPsychological Processes
Genes influence our psychological characteristics as well as our physical traits—the complete package of human genes=30,000
There are 46 chromosomes; 23 pairs
Multiple genes contribute to schizophrenia, Alzheimer’s disease; an extra chromosome 21 results in Down syndrome
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The body’s two communication systems, the
nervous system and the endocrine system, both use
chemical messengers to communicate with targets
throughout the body
How Does the Body How Does the Body Communicate Internally?Communicate Internally?
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The NeuronThe Neuron
Types of NeuronsSensory neurons—afferent--(carry
messages from sense receptors towards the CNS)
Motor neurons—efferent--(carry messages from CNS toward muscles and glands)
Interneurons (carry messages between nerve cells)
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The Neural ImpulseThe Neural Impulse
Neural impulse –Brief electric surge that carries the neuron’s message
Ions –Charged particles that are moved across the cell membrane
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The Neural ImpulseThe Neural Impulse
Resting potential—negative—when the cell is inactive and ready to fire
Action potential—impulse caused in a fraction of second when the charge changes from negative to positive…this is done in an all or none manner
Synapse—gap between neurons or neurons and muscles/glands
Synaptic transmission—relaying information across the synapse by use of chemical neurotransmitters
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NeurotransmittersNeurotransmitters
Neurotransmitters –Chemical messengers that relay neural messages across the synapse
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Seven Important NeurotransmittersSeven Important Neurotransmitters
DopamineDopamine
SerotoninSerotonin
AcetylcholineAcetylcholine
GlutamineGlutamine
NorepinephrineNorepinephrine
GABAGABA
EndorphinsEndorphins
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NeurotransmittersNeurotransmitters
DopamineDopamine
Serotonin
Acetylcholine
Glutamine
Norepinephrine
GABA
Endorphins
Normal Function:Normal Function:
Produces sensations of Produces sensations of pleasure and reward; used pleasure and reward; used
by CNS neurons in by CNS neurons in voluntary movementvoluntary movement
Problems with Imbalance:Problems with Imbalance:
Schizophrenia, Parkinson’s Schizophrenia, Parkinson’s diseasedisease
Substances that Affect:Substances that Affect:
Cocaine, amphetamines, Cocaine, amphetamines, Ritalin, alcoholRitalin, alcohol
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NeurotransmittersNeurotransmitters
Dopamine
SerotoninSerotonin
Acetylcholine
Glutamine
Norepinephrine
GABA
Endorphins
Normal Function:Normal Function:
Regulates sleep and Regulates sleep and dreaming, mood, pain, dreaming, mood, pain,
aggression, appetite and aggression, appetite and sexual behaviorsexual behavior
Problems with Imbalance:Problems with Imbalance:
Depression, certain anxiety Depression, certain anxiety disorders, obsessive-disorders, obsessive-compulsive disordercompulsive disorder
Substances that Affect:Substances that Affect:
Prozac, hallucinogenics Prozac, hallucinogenics (e.g. LSD)(e.g. LSD)
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NeurotransmittersNeurotransmitters
Dopamine
Serotonin
Acetylcholine
Glutamine
NorepinephrineNorepinephrine
GABA
Endorphins
Normal Function:Normal Function:
Controls heart rate, sleep, Controls heart rate, sleep, sexual responsiveness, sexual responsiveness,
stress, vigilance and stress, vigilance and appetiteappetite
Problems with Imbalance:Problems with Imbalance:
High blood pressure, High blood pressure, depressiondepression
Substances that Affect:Substances that Affect:
Tricyclic antidepressants, Tricyclic antidepressants, beta blockersbeta blockers
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NeurotransmittersNeurotransmitters
Dopamine
Serotonin
AcetylcholineAcetylcholine
Glutamine
Norepinephrine
GABA
Endorphins
Normal Function:Normal Function:
Primary transmitter used by Primary transmitter used by neurons carrying messages neurons carrying messages
from CNS; involved in from CNS; involved in some kinds of learning and some kinds of learning and
memorymemory
Problems with Imbalance:Problems with Imbalance:
Certain muscular disorders, Certain muscular disorders, Alzheimer’s diseaseAlzheimer’s disease
Substances that Affect:Substances that Affect:
Nicotine, botulism toxin, Nicotine, botulism toxin, curare, atropinecurare, atropine
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NeurotransmittersNeurotransmitters
Dopamine
Serotonin
Acetylcholine
Glutamine
Norepinephrine
GABAGABA
Endorphins
Normal Function:Normal Function:
Most prevalent inhibitory Most prevalent inhibitory neurotransmitter in neurons neurotransmitter in neurons
of CNSof CNS
Problems with Imbalance:Problems with Imbalance:
Anxiety, epilepsyAnxiety, epilepsy
Substances that Affect:Substances that Affect:
Barbiturates, tranquilizers Barbiturates, tranquilizers (e.g. Valium, Librium), (e.g. Valium, Librium),
alcoholalcohol
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NeurotransmittersNeurotransmitters
Dopamine
Serotonin
Acetylcholine
GlutamineGlutamine
Norepinephrine
GABA
Endorphins
Normal Function:Normal Function:
Primary excitatory Primary excitatory neurotransmitter in CNS; neurotransmitter in CNS; involved in learning and involved in learning and
memorymemory
Problems with Imbalance:Problems with Imbalance:
Brain damage after strokeBrain damage after stroke
Substances that Affect:Substances that Affect:
PCP (“angel dust”)PCP (“angel dust”)
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NeurotransmittersNeurotransmitters
Dopamine
Serotonin
Acetylcholine
Glutamine
Norepinephrine
GABA
EndorphinsEndorphins
Normal Function:Normal Function:
Pleasurable sensations and Pleasurable sensations and control of paincontrol of pain
Problems with Imbalance:Problems with Imbalance:
Lowered levels resulting Lowered levels resulting from opiate addictionfrom opiate addiction
Substances that Affect:Substances that Affect:
Opiates: opium, heroin, Opiates: opium, heroin, morphine, methadonemorphine, methadone
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PlasticityPlasticity
Plasticity –Ability of the nervous system to adapt or change as the result of experience; sometimes helps the nervous system adapt to physical damage
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Glial CellsGlial Cells
Glial cells (from the Greek for “glue”)• Provide structural support for neurons• Help in forming new synapses• Form myelin sheath• MS (multiple sclerosis) attacks the myelin
sheath resulting in poor conduction and loss of movement control
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The Organization of the The Organization of the Nervous SystemNervous System
Nervous systemNervous system
Peripheral nervous Peripheral nervous systemsystem
Central nervous Central nervous system (CNS)system (CNS)
AutonomicAutonomicnervous systemnervous system
SomaticSomaticnervous system—nervous system—splits into sensory splits into sensory
and motor NSand motor NS
SympatheticSympatheticnervous systemnervous system
Parasympathetic Parasympathetic nervous systemnervous system
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The Endocrine SystemThe Endocrine System(the body’s chemical messenger system)
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The Endocrine SystemThe Endocrine System
Pituitary gland – Master gland that produces hormones influencing the secretions of all other endocrine glands; produces hormone that influences growth; attached to hypothalamus
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How Does the Brain How Does the Brain Produce Behavior and Produce Behavior and
Mental Processes?Mental Processes?
The brain is composed of many specialized modules that work together to create
mind and behavior
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Windows on the BrainWindows on the Brain
EEG (electroencephalograph) – Device for recording brain waves, typically by electrodes placed on the scalp
Brain waves –Patterns of electrical activity generated by the brain
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Windows on the BrainWindows on the Brain
Epilepsy – Brain disorder that is often marked by seizures and loss of consciousness; caused by out-of-control electrical activity in the brain
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Windows on the BrainWindows on the Brain
Lesions –Tissue damage that results from disease or injury
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Windows on the BrainWindows on the Brain
Brain scans – Recordings of the brain’s electrical or biochemical activity at specific sites• CT scanning (computerized tomography) X rays are
passed through at various angles creating a static image of brain structure
• PET scanning (positron emission tomography) senses low-level radioactive glucose to create brightly colored areas of activity
• MRI (magnetic resonance imaging) also functional or fMRI creates highly detailed pictures from pulses of magnetic energy
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Three Layers of the BrainThree Layers of the Brain
Brain stem and cerebellumDrive vital functions, such as heart rate,
breathing, digestion
Limbic systemAdds emotions, complex motives, increased
memory abilities
CerebrumEnables reasoning, planning, creating,
problem solving
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The Brain Stem and CerebellumThe Brain Stem and Cerebellum
Thalamus
Pons
Cerebellum
Medulla
Brain stem
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The Limbic SystemThe Limbic System
Hypothalamus –Serves as the brain’s blood-testing laboratory, constantly monitors blood to determine the condition of the body
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The Limbic SystemThe Limbic System
Amygdala –Involved in memory and emotion, particularly fear and aggression
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The Limbic SystemThe Limbic System
Hippocampus –Involved in establishing long-term memories
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The CerebrumThe Cerebrum
Cerebrum –Topmost layer of the brain; the bulbous cap over the limbic system
Cerebral cortex –Thin gray-matter covering of the cerebrum; carries on thinking and perceiving=2/3 of brain’s total mass
Cerebral hemispheres –The two walnut shaped halves of the cerebrum, connected by the corpus callosum
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The Four Lobes of the The Four Lobes of the Cerebral CortexCerebral Cortex
Frontal lobes(movement…motor cortex, planning, deciding, perceiving)
Parietal lobes(touch sensation…somatosensory cortex and spatial relationships)
Occipital lobes(contain visual cortex)
Temporal lobes(process sounds/speech and has some ties to memory)
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The Cooperative BrainThe Cooperative Brain
Association cortex –Cortical regions that combine information from various other parts of the brain
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Cerebral DominanceCerebral Dominance
Cerebral dominance –Tendency of each brain hemisphere to exert control over different functions
Aphasia –The loss of speech caused by brain damageSpeech production lies in the frontal lobe, left hemisphere (Broca’s area. Understanding language lies in the left parietal and temporal lobes (Wernicke’s area).
Spatial orientation –Process of locating one’s body or other objects in space
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Specialization of the Specialization of the Cerebral HemispheresCerebral Hemispheres
Left Hemisphere Right Hemisphere• Spontaneous
speaking and writing
• Responses to complex commands
• Word recognition• Memory for words
and numbers• Sequences of
movements
• Positive emotion
• Repetitive but not spontaneous speaking
• Responses to simple commands
• Facial recognition• Memory for shapes
and music• Spatial interpretation• Emotional
responsiveness• Negative emotion
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The Split BrainThe Split Brain
Split-brain patients – Individuals who have had the corpus callosum surgically severed
Duality of consciousness – Condition in which a split-brain patient has a separate consciousness in each hemisphere