AP Psychology Unit 2:

1
AP Psychology Unit 2

• The Biological Bases of Behavior (Chapters 2 and
  4)

2
An Early History of Biopsychology

• Plato the mind is located in the brain
• Franz Gall and Phrenology
• Early 1800s
• Read bumps on skull to understand traits

Touch my sexy head lumps. Go on.touch them!
3
Biopsychology Today

• Everything we do is ultimately controlled by our
  body and brain
• Body/brain composed of cells
• Brain cells called neurons communicate
  electrically and chemically
• Different parts of the brain have specific
  functions
• Our brains create meaningful experiences from
  sensory information
• Brain structure and function is influenced by
  experience

4
Neurons Defining and Types

• A NEURON is a nerve cell.
• There are three basic types of neurons (diagram)
• Sensory Neurons Afferent neurons that detect
  stimuli from sense organs and relay this
  information TO the brain and/or spinal cord.
• Motor Neurons Efferent neurons that receive
  signals from the brain and/or spinal cord and
  relay this information to glands and muscles.
• Interneurons neurons in the brain and spinal
  cord that coodinate activity between sensory and
  motor neurons.
• Three Types of Neurons in action!
• Glial Cells provide nutrients to neurons,
  insulate neurons, and remove debris when neurons
  die.

5
Neuroanatomy (diagram)
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The Neural Impulse (diagram)

• Intraneural transmission within on neuron
• This is an ELECTRICAL process
• Occurs as a result of the exchange of charged
  particles called ions

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Neural Impulse Resting Potential

• When more negative ions are inside the neuron
  than outside
• Neuron is not transmitting information
• Similar to a compressed spring
• The neuron is POLARIZED meaning it has a charge
  (-)
• System WANTS to reach equilibrium and balance
  charges, but selectively permeable membrane is
  closed when in this state known as resting
  potential

8
Neural Impulse Action Potential

• Sudden, massive change in charge in the neuron
• Neuron reaches the threshold of excitation when
  neighboring neurons excitatory signals outnumber
  inhibitory signals
• Ions flow across cell membrane down axon (domino
  effect) facilitated by myelin sheath
• Na in, K out
• Neuron fires and DEPOLARIZES no charge

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Neural Impulse All-or-None Law

• A neuron either fires or it does not
• When it does fire, it will always produce an
  impulse of the same strength
• Intensity of a stimulus is coded by the frequency
  of action potentials or the number of neurons
  that fire

10
Neural Impulse Refractory
DudeIm in refractory. No action potential here

• Absolute refractory period
• Period immediately after an action potential when
  another action potential cannot occur
• Relative refractory period
• Period following absolute refractory period when
  a neuron will only respond to a stronger than
  normal impulse
• During the refractory period, the neuron is
  trying to get back to resting potential by
  pumping out K ions!

Hmpf.
11
So?

• Impulse has traveled down the length of the axon
• Signal end up at terminal buttons, very end
  points of the axon terminals
• Then what?
• Signal must get to other neurons, but how?

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The Synapse (diagram)

• The synapse
• Composed of the terminal button of one neuron,
  the synaptic space, and the dendrites or cell
  body of the receiving neuron
• Synaptic space (synaptic cleft)
• Tiny gap between neurons
• Messages must travel across the space to get from
  one neuron to the next

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Transmission Between Neurons
Presynaptic Neuron

• Interneural between neurons
• a CHEMICAL process
• Synaptic vesicles
• Sacs in terminal button that release chemicals
  into synaptic space
• Neurotransmitters
• Chemicals released by synaptic vesicles
• Receptor sites
• Location on receptor neuron for specific
  neurotransmitter
• Lock and key
• Reuptake
• Recycling neurotransmitters

Postsynaptic Neuron
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Putting it together
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Neurotransmitters and Behavior (diagram)

• Neurotransmitters regulate many aspects of
  behavior
• An imbalance of neurotransmitters may cause
  maladaptive behavior
• Neurotransmitters may be inhibitory, excitatory
  or both

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Drugs and Neurotransmitters

• Drugs impact on the body has helped scientists
  discover neurotransmitters, neuropeptides (e.g.
  amino acids such as endorphins) and
  neuromodulators that can increase or decrease the
  activity of certain neurotransmitters
• How do drugs work?
• Agonists mimic or prevent reuptake (1, 3)
• Antagonists block neurotransmission (2)

17
Psychopharmacology

• Botulism
• Blocks release of ACh at the neuromuscular
  junction, causing paralysis
• Botox is botulism toxin used to prevent facial
  muscles from making wrinkles
• Curare found in vines in S. America used as
  poison
• Can stun or kill prey quickly
• Blocks ACh receptors causing paralysis

• Antipsychotic medications
• Block dopamine receptors
• Reduces schizophrenic hallucinations
• Caffeine
• Increases the release of excitatory
  neurotransmitters by blocking the inhibitory
  neurotransmitter adenosine
• Cocaine
• Prevents reuptake of dopamine
• Leads to heightened arousal of entire nervous
  system

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The Nervous System (diagram)
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The Autonomic Nervous System (diagram)

• Fight-or-flight response
• Sympathetic Arouses
• Parasympathetic Calms

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Central Nervous System (CNS)
Central Nervous System
Brain
Spinal Cord

• Brain
• Enables all functioning
• Billions of neurons and their connections
• These neurons work together in neural networks to
  facilitate efficient output.
• As we learn, these networks strengthen
• Spinal Cord
• Connects brain to PNS
• Handles reflexes

I rule.
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The Endocrine System (diagram)
Tell me about it!
I hate being naked in front of all these students

• Helps coordinate and integrate complex
  psychological reactions
• Endocrine glands secrete hormones into the
  bloodstream
• Hormones serve to organize the nervous system and
  body
• Hormones also activate behavior, such as sexual
  behavior, hunger and aggression

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Endocrine Glands (diagram)
Dunno.
Got diabeeetus?
diabeetusfetus

• Thyroid gland
• Secretes hormones (primarily thyroxin) that
  control metabolism
• Hypothyroidism and Hyperthyroidism
• Pineal gland
• Sleep-wake cycle
• Secretes melatonin
• Pancreas
• Regulates blood-sugar levels
• Secretes insulin
• Diabetes?

• Pituitary gland
• Referred to as the master gland
• regulates many other glands
• Adrenal glands
• Reaction to stress
• Secretes adrenaline (epinephrine)
• Gonads
• Ovaries and testes
• secrete estrogens and androgens

23
The Brain

• Without our brains, we would really be nothing!
• The mind is what the brain does

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Studying the Brain

• Studying the brain through lesions or damaged
  areas
• Ta and Phineas Gage
• Experiments in rats hypothalamus lesions
• Monitoring Electrical Activity the EEG
• Electroencephalograms provide information about
  cortical activity
• Record electrical activity of neurons on surface
  of brain (neural firing)
• A functional technique

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Studying the Brain Structural Neuroimaging
Techniques

• CT Scan (Computerized tomography)
• Computer-assisted x-ray of brain
• Used to create overall images of brain
• MRI (Magnetic Resonance Imaging)
• Produces detailed pictures of soft tissue in
  brain
• Can focus on specific regions when CT cannot
  produce clear images

CT scan (top) and MRI (bottom) showing a tumor.
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Studying the Brain Functional Neuroimaging
Techniques

• PET (positron emission tomography)
• Image created by the rate at which radioactive
  glucose is metabolized
• Which areas of the brain are active during a
  particular activity
• fMRI (functional MRI)
• Combines structural and functional techniques
• Multiple images of brain created during a
  particular task
• Records changes in blood flow to indicate regions
  of greater activity

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Primitive Brain Structures

• Brainstem
• Oldest part of brain
• Contains medulla, controlling heartbeat, blood
  pressure and breathing
• Also contains pons, which helps regulate sensory
  information and facial expressions
• Contains Reticular Formation (RF) for
  alertness/arousal, sleep/wakefulness
• Thalamus
• Pair of egg-shaped structures on top of brainstem
• Routes all incoming sensory information except
  for smell to appropriate areas of brain
• Cerebellum
• little brain at read of brainstem
• Controls coordination, balance, and muscle tone

• These parts of the brain are our autopilot so
  other regions can deal with higher-level human
  functions

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The Limbic System

• Located in between the primitive parts of the
  brain and the cerebral hemispheres
• Hippocampus processes new memories (case of H.M.)
• Amygdala controls emotions such as aggression and
  fear in animals, the attack response (rat
  study)
• Hypothalamus regulates hunger, thirst, body
  temperature and sex drive also controls
  pituitary gland
• Rat study self-stimulation of pleasure
  centers
• Human implications? Mild pleasure, addiction
  tendencies?
• Primarily, the limbic system processes drives,
  smell and various emotional responses

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The Cortex

• Part of the cerebrum, the two large hemispheres
  comprising 85 of brain weight
• Wrinkled outer layer
• Why so convoluted?
• Higher level functions
• Designation of cortical space and higher level
  animals?
• Most highly evolved part of the human brain

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Cortex Breakdown

• Each hemisphere is divided into 4 lobes
• Frontal lobe
• Temporal lobe
• Parietal lobe
• Occipital lobe
• The lobes are separated by deep convolutions
  known as fissures

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Cortex Breakdown
Homunculous!

• Occipital Lobes
• Visual cortex
• Damage?
• Temporal Lobes
• Auditory cortex
• Auditory hallucinations?

• Parietal Lobes
• Primary sensory or somatosensory cortex
• Allocation of space?
• Frontal Lobes
• Most evolved
• Motor cortex, which allows us to move
• Allocation of space?

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Motor and Sensory Cortex Revealed!
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The Cortex Association Areas

• We only use 10 of our brains?
• Undifferentiated cortex
• Association areas

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Phineas Gage A Case Study in Frontal Lobe
Association Area Damage

• In 1848, railroad foreman Phineas Gage
  accident!
• No longer himself
• Emotions, the frontal cortex, and the unchecked
  limbic system

The skull of Phineas and rogue tamping iron,
displayed proudly at Harvard Universitys medical
school! For real!
35
Neuroplasticity
Shafted again.

• Brains to change and reorganize as a result of
  experience
• Mark Rosenzweigs (1922-2009) Rat Studies
  (1950s-60s)
• Implications for humans?

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Party!
36
Neuroplasticity in Rats
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(No Transcript)
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Neurogenesis?

• Recent evidence has suggested that human brains
  may be able to generate new brain cells, known as
  Neurogenesis
• Stem cell research?

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The Two Hemispheres

• Two halves are NOT identical
• Most have a dominant hemisphere usually the
  left, which controls the right side of the body
• Both sides serve important functions, revealed by
  studying split-brain patients

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Split-Brain

• Epilepsy, seizures and the corpus callosum
• Reduction in epileptic seizures
• Different abilities in each hemisphere
• The story of Vicki
• Michael Gazzaniga

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Some Hemispheric Strengths

• Left Hemisphere
• Language in most people The cases of Ta of
  Charles Landry
• Logic
• Right side of body
• Right Hemisphere
• Perception
• Sense of self
• Inferences

42
Hemispheric Dominance Handedness

• 90 of humans are right-handed
• The 10 of left-handers show less predictable
  patterns of hemispheric dominance
• Causes?
• Genetics?
• Fetal testosterone levels?
• Learned?
• Handedness and sexual orientation?
• A closer look a curse or an advantage?

43
Behavior GeneticsWhats the Point?

• Behavior Genetics seeks to understand the
  relative influence of our heredity and our
  experiences
• Nature vs. Nurture? Its both but how much of
  each?

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Behavior GeneticsGenetics Review

• Heredity examines the transmission of trait from
  one generation to next
• Chromosomes
• Pairs of thread like bodies that contain genes
• Average human cell has 23 pairs
• Sex cells?
• Deoxyribonucleic acid (DNA)
• Organic molecule arranged in a double-helix
• Contains the code of life
• Genes
• Basic units of inheritance
• Segment of DNA
• Genome
• map for an organisms genetic complete make-up
• Human Genome Project

45
Behavioral GeneticsStudying Nature vs. Nurture

• Animal Studies
• Strain Studies
• Selection Studies
• Human Studies
• Identical Twins
• Fraternal Twins
• Separated Twins
• Adoption Studies
• Family studies

46
Behavioral GeneticsTemperament and Heritability

• Temperament refers to emotional reactivity and
  seems to be set very early in life
• Thomas and Chess (easy, difficult,
  slow-to-warm-up)
• Kagans shy child
• Indicates this aspect of behavior is genetically
  manipulated
• Environment can enhance or diminish this genetic
  predisposition

47
Behavior Genetics Heritability

• Heritability the extent to which differences
  among organisms are caused by genes
• Does NOT refer to which percentage of a trait is
  determined by genetics in a given individual!
• The more similar and controlled the environment
  of the organisms is, the more we can attribute
  differences to genes, and the higher the
  heritability!

48
SoNature vs. Nurture?

• Genes and environment interact like two hands
  clapping
• Environment can trigger genetic switches
• Our genes can provoke us to seek particular
  environments
• e.g. Eating Disorders
• Genetic predisposition (some are more susceptible
  than others)
• Cultural regulation (Western culture)
• Molecular Genetics
• Studies how particular genes influence behavior
• e.g. Is there a gene that determines obesity?
  Sexual orientation?
• Promise and peril of molecular genetics?
• Genetic engineering
• Eugenics

49
Evolutionary Psychology

• Whereas behavior geneticists seek to explain our
  behavioral differences in terms of our genes,
  evolutionary psychologists focus on our
  similarities, as dictated by natural selection.
• Richard Dawkins The Selfish Gene (1976)
• Varied organisms in a population compete to
  survive
• Certain biological and behavioral variations
  facilitate survival
• Surviving organisms may reproduce and pass on
  their genes
• This leads to overall changing characteristics in
  a population

50
Evolutionary PsychologyNatural Selection,
Adaptation and Evolutionary Success

• Selection providing a reproductive advantage,
  either naturally or artificially (e.g. tame
  foxes), based on a trait/set of traits
• These traits will endure over time
• Population will change as a result
• Variation can result from mutations (errors in
  genetic replication right after conception)
• Some of these errors provide an advantage and
  are selected for, and therefore persist
• The errors are adaptive increasing our fitness,
  or our chances to survive (and to reproduce)
• Humans have so many shared characteristics How?
• Differences that were not fit were not passed
  on
• Those that increased survival were, as these
  organisms lived and reproduced

51
Evolutionary Psychology

• Selection happens SLOWLY and often our world
  changes faster than the gene pool can (e.g.
  fatty/sweet food cravings)
• Today, evolutionary psychologists examine
  persistent trends in human behavior and seek to
  explain them
• Keep in mind, however, that genetically driven
  tendencies only partially govern human behavior!

52
Evolutionary PsychologyExplaining Human
Sexuality and Mating

• Males of all sexualities generally are more
  interested in sex, regard sex as a recreational
  activity and prefer young, attractive mates
• Females of all sexualities generally see sex as
  an outgrowth of relationships and prefer mature,
  stable, and affluent mates
• Have these trends genetically motivated?

53
Evolutionary PsychologyHuman Sexuality and
Mating

• Women
• Quality over quantity
• More invested in bearing/nurturing children
• Seek men who either provide superb genes (he-man
  strategy) or are good providers (domestic-bliss
  strategy)
• fast vs. coy females
• Men
• Quantity over quality
• Increase reproductive success by spreading their
  genes as widely as possible
• Attraction to fertile females
• Not physically bound to pregnancy
• He-man strategy vs. opportunists
• Philanderers vs. Stable males?

Perhaps males should invest more in child-rearing?
54
Evolutionary PsychologyCriticism

• Do these arguments just provide excuses for bad
  behavior?
• Do humans have more of a social and cultural
  responsibility to make the world better?
• What about environmental influence?
• How does the environment reinforce these trends?
• How much of a role does environment play in the
  persistence of these roles?
• Who benefits?

55
Parents and Peers

• Experience and Brain Development
• Critical Periods
• Rosenzweig revisited
• Brains are shaped by our genes AND experience
• Parental Influence?
• If abusive or neglectful, can have major impact
• In non-extreme cases, parents probably deserve
  less credit, or less blame!
• Parents shape values, beliefs and habits, but not
  as much as we may believe
• Most important to provide unconditional love and
  support
• Peer Influence
• Peers teach us how to socialize and cooperate
• Selection effect seeking peers with similar
  interests

56
Cultural Influences

• Culture
• distinctive values, beliefs, language and
  characteristics of a society
• both tangible (food, clothing) and intangible
  (values, beliefs).
• Norms
• Rules that represent the typical behaviors of a
  particular group
• One example is expected personal space, the
  distance we like to keep ourselves from other
  people

57
Individualism vs. Collectivism

• Individualist cultures place value of singular
  person over that of the group
• Collectivist cultures value the group over the
  individual
• Which type of culture does the US have? Why?
• Implications?

58
Gender DevelopmentAggression, Power, and
Connectedness

• Aggression involves an intent to harm, whether
  verbal or physical males admit to and exhibit
  more than females.
• Men are and are perceived as more powerful and
  engage in behaviors that exhibit and perpetuate
  this power inequity.
• Females place greater emphasis on social
  connections, choosing careers that involve social
  interaction or require nurturing roles
• Males have more difficulty admitting they are
  wrong

59
Why Are We Different?Biological Explanations

• X and Y Chromosomes
• Y triggers sex differentiation during fetal
  development, causing greater testosterone
  production in males
• Female infants exposed to elevated levels of
  testosterone exhibit male behavioral
  characteristics
• Males with normal male hormones but had their sex
  reassigned at birth for various reasons often
  embrace a male identity, despite efforts to raise
  them as females

60
Why Are We Different?Social Explanations

• Gender Roles expected behaviors for males and
  females
• Women as caregivers?
• Men as breadwinners?
• The Reality? Women now OUTNUMBER men in the
  workplace in the US, yet in 87 of families with
  children, are still the primary caregivers.
• Variations across culture and time
• Gender Identity our sense of being male or
  female
• Gender typing embracing a traditional
  masculine/feminine role
• Social Learning Theory and Gender Schemas
• What do these roles and stereotypes provide for
  us?
• Sense of stability and simplification
• Sense of confinement

61
Nature vs. Nurture?Call the Whole Thing Off!

• Our genes and our experiences form us
• Family, friends, and culture have an influence
  over the genes that make us
• These structures are constantly in flux
• We are adaptive creatures
• The world changes, and we change with it