Chapter 2: Biology and Behavior Lecture 3

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Chapter 2 Biology and BehaviorLecture 3
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Learning Outcomes

• Describe the nervous system, including neurons,
  neural impulses, and neurotransmitters.
• List the structures of the brain and their
  functions.

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Learning Outcomes

• Describe evolutionary psychology and the
  connections between heredity, behavior, and
  mental processes.

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The Nervous System On Being Wired
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1. Neurons

• Neurons, responsible for all our sensations,
  behaviors and mental processes, our nervous
  system composed of those cells
• Cell body-soma, dendrites, axon and axon
  terminals
• Glial cells ( increases when we grow up)
• Nourish and insulate neurons
• Direct growth of neurons
• Remove waste products
• Myelin sheath (axon is wrapped w/it, white, fatty)

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2. The Anatomy of a Neuron
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3. Neurons

• Afferent Neurons/Sensory
• Transmit messages from sensory receptors to the
  spinal cord and brain
• Efferent Neurons/Motor
• Transmit messages from bran or spinal cord to
  muscles and glands
• SAME

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4. Neural Impulse

• Electrochemical messages that travel within
  neurons
• Resting potential (-70), because of Sodium (Na)
  Potassium(K) pumps and chloride (Cl-)
• Neuron is not responding to other neurons
• Electrotonic potential (will sum up in soma)
• Action potential
• Conduction of neural impulse along axon

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4. Neural Impulse

• Electrochemical messages that travel within
  neurons
• Resting potential (-70), because of Sodium (Na)
  Potassium(K) pumps and chloride (Cl-)
• Neuron is not responding to other neurons
• Action potential
• Conduction of neural impulse along axon

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(e.g.,-55ml- Na channels open up, and Na floods
in until 30 or 40, then Na channel closes and
Potassium K channels open up until -80 )
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Action Potential
PLAY VIDEO
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5. Firing Neuron to Neuron

• Firing
• Conduction of neural impulse along the length of
  a neuron
• Threshold
• Incoming messages reach a strength at which
  neuron will fire (e.g.,-55ml- Na channels open
  up, and Na floods in until 40, then Na channel
  closes and Potassium K channels open up until
  -80 )

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6. Firing Neuron to Neuron

• All-or-none principle
• Every time a neuron fires, it transmits an
  impulse of the same strength.
• Refractory period
• Period of recovery time between firings

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7. Firing Neuron to Neuron

• Synapse
• Fluid-filled gap (Synaptic cleft) between
• Axon terminal from transmitting neuron, and
• Dendrite of receiving neuron

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Synaptic Transmission
PLAY VIDEO
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8. Neurotransmitters

• Neurotransmitters
• Chemical substances that communicate from one
  neuron to another
• Synaptic vesicles
• Contain neurotransmitters in the axon terminals

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9. Neurotransmitters

• Receptor site
• On dendrite of receiving neuron
• Reuptake
• Neurotransmitters reabsorbed

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10.Neurotransmitters

• Excitatory neurotransmitter (e.g., Na channels
  open)
• Cause other neurons to fire
• Inhibitory neurotransmitters (e.g., Potassium K
  channels open)
• Prevent other neurons from firing

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To Sum up Firing

• Neurons communicate by firing. Steps
• a). Neurotransmitters are released into
  synapse by a pre-synaptic neuron
• b). Neurotransmitters bind with receptors
  on the post-synaptic neurons dendrites
• c). Excitatory and inhibitory messages are
  compared in the cell body (soma) of the
  postsynaptic neuron.
• d). If the receptors allow a sufficient
  excess of excitatory neurotransmitters into the
  cell, the postsynaptic neuron will respond by
  opening its sodium and potassium gates.
• e). The charge inside the cell goes from
  negative to positive
• f). The gates open in succession as the
  information is passed along the axon away from
  the cell body and toward terminal buttons.
• g). The sodium and potassium gates close,
  and the neuron returns to its resting potential
• h). The synaptic neuron reuptakes the
  neurotransmitter from the synapse.

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11. Neurotransmitters of Interest to Psychologists

• Acetylcholine (ACh)
• Controls muscle contractions (excitatory between
  nerves muscles inhibitory at the heart and some
  other locations)
• Paralysis if not enough ACh
• Memory (prevalent in hippocampus, when decrease )
• Alzheimers disease
• Acetylcholine (ACh), Dopamine, norepinephrine,
  serotonin, GABA, and endorphins

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12. Neurotransmitters of Interest to Psychologists

• Dopamine
• Pleasure, voluntary movement, learning, memory
• Parkinsons disease (deficiencies in D.)
• Schizophrenia (people have more receptors for
  dopamine, utilize more dopamine)
• -Phenothiazines block dopamine receptors
• Acetylcholine (ACh), Dopamine, norepinephrine,
  serotonin, GABA, and endorphins

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13. Neurotransmitters of Interest to Psychologists

• Norepinephrine in the brain stem
• Excitatory neurotransmitter, also hormone
• Accelerates heart rate, affects eating, linked to
  activity levels, learning and remembering
• Mood disorders, depression, bipolar disorder
  (more)
• -- Deficiency impairs memory
• -- Cocaine and amphetamines boost N.
• Acetylcholine (ACh), dopamine, norepinephrine,
  serotonin, GABA, and endorphins

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14. Neurotransmitters of Interest to Psychologists

• Serotonin
• Emotional arousal and sleep
• Eating disorders, alcoholism, depression,
  aggression, insomnia
• LSDs decrease action of S.
• Acetylcholine (ACh), dopamine, norepinephrine,
  serotonin, GABA, and endorphins

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15. Neurotransmitters of Interest to Psychologists

• Gamma-aminobutyric acid (GABA)
• Inhibitory may help relax anxiety reactions
• Depression

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16. Neurotransmitters of Interest to Psychologists

• Endorphins similar to morphine
• Occur naturally within the brain and bloodstream
• Inhibit pain
• Increase sense of competence, immune
• May be connected to indifference to pain
• Runners high

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17. Parts of the Nervous System

• Central Nervous System
• Brain and spinal cord
• Peripheral Nervous System
• Sensory (afferent) and motor (efferent) neurons

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The Divisions of the Nervous System
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18. Peripheral Nervous System

• Somatic Nervous System
• Sensory and motor neurons
• Transmits messages to the brain and purposeful
  body movements from the brain
• Autonomic Nervous System
• Regulates glands and muscles of internal organs
• Contains sympathetic and parasympathetic divisions

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19. Branches of Autonomic Nervous System

• Sympathetic
• Most active during emotional responses
• Spend the bodys reserves of energy
• Parasympathetic
• Most active during processes that restore bodys
  reserve of energy

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20. Central Nervous System

• Spinal Cord information superhighway
• Transmits messages from sensory receptors to the
  brain and from the brain to muscle and glands
• Spinal Reflex- local government
• Simple, unlearned response to stimulus
• Gray matter, involved in spinal reflexes
• White matter

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The Reflex Arc
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The Brain Wider Than the SkyLecture 4.
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How Do Researchers Learn About the Functions of
the Brain

• Experimenting with the brain
• Assessing damage from trauma and disease
• Intentionally damaging parts of a brain
• Electrical probes to stimulate parts of the brain
• Electroencephalograph (ECG)
• Measurement of electrical activity brain waves

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How Do Researchers Learn About the Functions of
the Brain (continued)

• Brain-Imaging Techniques
• Computerized axial tomography (CAT or CT scan)
• Positron emission tomography (PET scan)
• Magnetic Resonance Imaging (MRI)
• Functional Magnetic Resonance Imaging (fMRI)

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1.Structures and Functions of the Brain

• Hindbrain
• Medulla -heart rate, blood pressure,
  respiration/breathing sleeping, sneezing,
  coughing.
• Pons- body movements related to attention, sleep,
  alertness, respiration
• Cerebellum- balance, controls motor
  behavior-e.g., playing guitar , walking to
  refrigerator.

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2. Structures and Functions of the Brain

• Reticular Activation System
• Vital to attention, sleep, arousal
• Injury to the RAS results in coma
• -alcohol lowers RAS activity

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3. Structures and Functions of the Brain

• Forebrain includes the thalamus, hypothalamus,
  limbic system, cerebrum
• Thalamus
• Relay station for sensory stimulation
• Hypothalamus
• Regulates body temperature, motivation and
  emotion
• Hunger, thirst, sexual behavior, caring for
  offspring, aggression

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4. Structures and Functions of the Brain

• Forebrain
• Limbic System, includes the amygdala,
  hippocampus, parts of hypothalamus
• Involved in memory, emotion, hunger, sex drive,
  aggression
• Amygdala- fear

Involved in memory and emotion
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5. Structures and Functions of the Brain

• Cerebrum
• Responsible for thinking and language
• Cerebral Cortex
• Surface of cerebrum
• Corpus Callosum
• Connects two hemispheres

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6. The Brain Corpus Callosum
PLAY VIDEO
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7. The Cerebral Cortex

• Outer layer of cerebrum
• Two Hemispheres
• Four Lobes
• Frontal, Parietal, Temporal and Occipital

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8. The Lobes of the Cerebral Cortex

• Occipital Lobe
• Vision
• Temporal Lobe
• Hearing and Auditory functions
• Parietal Lobe
• Somatosensory Cortex, m. from skin
• Frontal Lobe
• Motor Cortex

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The cerebral cortex. Which of the following
body parts is associated with the greatest amount
of brain tissue in the motor cortex?
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9. Thinking, Language, and the Cortex

• Association areas
• Not primarily involved in sensation or motor
  activity
• Responsible for learning, thought, memory and
  language
• Association areas in frontal lobe
• Responsible for executive functions

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10.Language Functions

• Two hemispheres of the brain mirror and differ
• Left hemisphere contains language functions for
  nearly all people
• If damaged before age 13, speech functions would
  transfer to right hemisphere
• Two key language areas
• Brocas area Wernickes area
• Damage in either causes aphasia

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11. Language Functions

• Wernickes Area
• Temporal Lobe
• Wernickes aphasia
• Impairs ability to comprehend speech and think of
  words to express own thoughts
• Angular Gyrus
• Translates visual into auditory information
• Damage impairs reading ability

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12. Language Functions

• Brocas Area
• Frontal Lobe
• Production of speech
• Brocas aphasia
• Understand language but speak slowly and
  laboriously

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13. Left Brain, Right Brain

• Left-brained
• Logical and intellectual
• Right-brained (visual-spacial)
• Intuitive, creative and emotional
• Hemispheres do not act independently
• Exaggerated idea

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14. Handedness

• Left-handed
• Somewhat greater-than-average probability of
  language problems and certain health problems
• More likely than right-handed people in gifted
  artists, musicians, and mathematicians
• Origins of handedness
• Genetics
• 1 left-handed parent -80 to be right handed 2
  left-handed parents-50

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15. Split-Brain Experiments

• Severe cases of epilepsy may require split-brain
  operations
• Examples of two brain phenomenon
• Caused by inability of one hemisphere to
  communicate with the other

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Evolution and HeredityThe Nature of Nature
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Darwins Theory of Evolution

• Struggle for existence
• Natural selection
• Species and individuals compete for same
  resources
• Mutations
• Random genetic variations explain differences
• Differences which affect the ability to adapt to
  change

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Evolutionary Psychology

• Ways in which adaptation and natural selection
  are connected with behavior and mental processes
• Behavior patterns evolve and can be transmitted
  genetically from generation to generation
• Instinctive or species specific behaviors

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Evolutionary Psychology

• Instinct
• Stereotyped patterns of behavior that are
  triggered in a specific situation
• Species-specific
• Resists modification, not learned

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Heredity, Genetics and Behavioral Genetics

• Heredity
• Transmission of traits from parent to offspring,
  based on genes
• Genetics
• Subfield of biology that studies heredity
• Behavioral Genetics
• Focuses on individual differences

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Genes and Chromosomes

• Gene
• Basic unit of heredity
• Chromosomes
• Structure within cell nucleus that carry genes
• Humans have 46 chromosomes (23 pairs)
• DNA (deoxyribonucleic acid)
• Substance that forms chromosomes
• Double helix contains genetic code
• Nucleotides - A and T, C and G

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Cells, Chromosomes, and DNA
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Genes and Chromosomes

• Genes regulate development of specific traits
• Some traits are determined by one gene
• Other traits are polygenic

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Genes and Chromosomes

• Genotype
• Individuals genetic makeup (nature)
• Phenotype
• Actual appearance, based on genotype and
  environmental influences (nurture)

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Chromosomes

• Receive 23 chromosomes from fathers sperm and 23
  chromosomes from mothers egg cell
• 23rd pair of chromosomes are sex chromosomes
• XX female
• XY male
• Down syndrome
• Chromosomal abnormality

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Kinship Studies

• Focus on presence of traits and behavior patterns
  in people who are, or are not related
  biologically
• Twin studies
• Monozygotic twins
• Dizygotic twins
• Adoption studies

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Left Handedness

• 8 to 10 of people are left handed
• More common in boys than girls
• More common in gifted artists than general
  population
• Language and Health Problems
• Dyslexia, stuttering
• Migraine headaches, allergies
• Appears to have a genetic component

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Selective Breeding

• Process used to enhance desired physical and
  behavioral traits
• Done routinely with plants and animals