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Chapter 2Chapter 2Biological Foundations of Biological Foundations of

BehaviorBehavior

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Module 2.1Module 2.1Neurons: The Body’s WiringNeurons: The Body’s Wiring

Its EVOLUTION!Its EVOLUTION!

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What is our advantage?What is our advantage?

What puts us at a major advantage over What puts us at a major advantage over other animals which puts us at the top of other animals which puts us at the top of the food chain?the food chain?

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Our Brain!Our Brain!

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It’s Evolution Baby!It’s Evolution Baby!

The human brain is a product of The human brain is a product of generations of adaptive mutations and generations of adaptive mutations and adaptations.adaptations.

Homo sapiens-100,000 years old (is this Homo sapiens-100,000 years old (is this old?)old?)

What the heck is natural selection?What the heck is natural selection?

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The original Chuck D: The original Chuck D: Charles DarwinCharles Darwin

Evolve: To develop gradually.Evolve: To develop gradually. Gradual change in the structure of an Gradual change in the structure of an

animal or plant as a result of natural animal or plant as a result of natural selection.selection.

NS= process by which inherited traits that NS= process by which inherited traits that lead to a selective advantage increase the lead to a selective advantage increase the likelihood of reproduction.likelihood of reproduction.

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The Adaptive HumanThe Adaptive Human

Brain size correlates with Brain size correlates with intelligence? T or Fintelligence? T or F

Bigger brain=Smarter?Bigger brain=Smarter?

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Cephalisation IndexCephalisation Index Ratio of brain weight to body weight.Ratio of brain weight to body weight.

K=E/P K=E/P

K=Cephalisation IndexK=Cephalisation Index

E=Brain weight in gramsE=Brain weight in grams

P=Body weight in kilogramsP=Body weight in kilograms

Real Smart: Humans: .89

Dolphins: .64

Chimp:.30

Real Dumb: Sheep: .10

Rabbit: .05

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Neurons!Neurons!

The basic building block of the The basic building block of the nervous systemnervous system– CellsCells– Transmit information via an electro-Transmit information via an electro-

chemical process. chemical process.

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Chapter 2Chapter 2Biological Foundations of Biological Foundations of

BehaviorBehavior

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Figure 2.1: The NeuronFigure 2.1: The Neuron

soma

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Cells in the Nervous SystemCells in the Nervous System

Three types of neuronsThree types of neurons– Sensory neurons (or “afferent neurons”)Sensory neurons (or “afferent neurons”)– Motor neurons (or “efferent neurons”)Motor neurons (or “efferent neurons”)– Interneurons (or “associative neurons”)Interneurons (or “associative neurons”)

Glial cells (the glue!)Glial cells (the glue!)– Account for 90% of cells in adult human Account for 90% of cells in adult human

brainbrain– Help hold neurons togetherHelp hold neurons together– Provide supports for the nervous systemProvide supports for the nervous system

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Cells in the Nervous SystemCells in the Nervous System Sensory Neurons:Sensory Neurons:

– Afferent nervesAfferent nerves– Information about the outside world to Information about the outside world to

the brain.the brain.– Sensory organs to brain.Sensory organs to brain.– 5 senses5 senses

– ““That stinks!”That stinks!”

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Cells in the Nervous SystemCells in the Nervous System

Motor NeuronsMotor Neurons– Efferent NervesEfferent Nerves– Sends message from the brain to the Sends message from the brain to the

muscles and glands to cause muscles and glands to cause response/behavior or to regulate bodily response/behavior or to regulate bodily processes.processes.

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Cells in the Nervous SystemCells in the Nervous System

InterneuronInterneuron– Most common neuron in the NSMost common neuron in the NS– Connect neurons to neuronsConnect neurons to neurons– Connect sensory to motor, motor to Connect sensory to motor, motor to

sensorysensory

– More on this later……I promiseMore on this later……I promise

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How do they talk?How do they talk?

Electro-Chemical processElectro-Chemical process– Sodium (Na+) and Potassium (K+)Sodium (Na+) and Potassium (K+)– A cell at rest – 70 (mV).A cell at rest – 70 (mV).– Cell begins to let positive ions into the cell, Cell begins to let positive ions into the cell,

changing the polarity to + (40 mV)changing the polarity to + (40 mV)– This is an This is an action potential action potential (firing or (firing or

‘spiking’)‘spiking’)– All-or-none Principle:All-or-none Principle:

Must have a full voltage of + 40 mv to fire.Must have a full voltage of + 40 mv to fire. Won’t half fire or semi fire.Won’t half fire or semi fire.

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Action PotentialsAction Potentials

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What’s next?What’s next?

Neurotransmission!Neurotransmission!– When the neuron fires, the axon’s When the neuron fires, the axon’s

terminal buttons release molecules of terminal buttons release molecules of NT’s into synaptic gap.NT’s into synaptic gap.

– They bind to Receptor sites on the They bind to Receptor sites on the dendrites of other neurons.dendrites of other neurons.

– 2 possible outcomes:2 possible outcomes: ExcitatoryExcitatory InhibitoryInhibitory

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Module 2.2Module 2.2The Nervous System: The Nervous System:

Your Body’s Information SuperhighwayYour Body’s Information Superhighway

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Figure 2.4: Parts of the Figure 2.4: Parts of the Nervous SystemNervous System

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Concept Chart 2.2: Concept Chart 2.2: Organization of the Nervous Organization of the Nervous

SystemSystemThe Nervous System

CentralNervous System

Peripheral Nervous System

Spinal Chord BrainSomatic

Nervous SystemAutonomic

Nervous System

SympatheticNervous System

ParasympatheticNervous System

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Spinal CordSpinal Cord

Column of nerves extending from Column of nerves extending from brainbrain– Protected by the spineProtected by the spine– Transmits information between the brain Transmits information between the brain

and the peripheral nervous systemand the peripheral nervous system Controls some spinal reflexesControls some spinal reflexes

– Allows quick responses to particular Allows quick responses to particular types of stimuli (evolution)types of stimuli (evolution)

CNS regulates everything in the CNS regulates everything in the body.body.

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Figure 2.5a: The Knee-Jerk Figure 2.5a: The Knee-Jerk ReflexReflex

afferent efferent

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Figure 2.5b: The Withdrawal Figure 2.5b: The Withdrawal ReflexReflex

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Peripheral Nervous SystemPeripheral Nervous System

Connects the CNS with other body partsConnects the CNS with other body parts Divided into 2 parts:Divided into 2 parts:

– Somatic Nervous SystemSomatic Nervous System: Transmits : Transmits messages between CNS and the sensory messages between CNS and the sensory organs, glands, and muscles (moves ya organs, glands, and muscles (moves ya around)around)

– Autonomic Nervous System (ANS)Autonomic Nervous System (ANS): Controls : Controls internal bodily processesinternal bodily processes

– BP, Heart Rate, Etc…not aware but may be BP, Heart Rate, Etc…not aware but may be affected by conscious things (stress, anger)affected by conscious things (stress, anger)

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Divisions of the ANSDivisions of the ANS

Sympathetic Nervous SystemSympathetic Nervous System– Speeds up bodily processesSpeeds up bodily processes– Draws energy from stored reservesDraws energy from stored reserves– Activation often accompanied by strong Activation often accompanied by strong

emotionsemotions Parasympathetic Nervous SystemParasympathetic Nervous System

– Fosters bodily processes that replenish energy Fosters bodily processes that replenish energy storesstores

– Helps conserve energy by slowing down other Helps conserve energy by slowing down other bodily processesbodily processes

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Module 2.3Module 2.3The Brain: Your Crowning GloryThe Brain: Your Crowning Glory

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Brain FactsBrain Facts

Average number of neurons in the brain = 100 Average number of neurons in the brain = 100 billion billion

The average brain weighs about 3 pounds.The average brain weighs about 3 pounds. 77% of a human brain is dedicated to the cerebral 77% of a human brain is dedicated to the cerebral

cortex.cortex. 31% is dedicated to a rat’s.31% is dedicated to a rat’s.

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HindbrainHindbrainKickin’ it old school!Kickin’ it old school!

Lowest, oldest part of the brainLowest, oldest part of the brain Includes the:Includes the:

– Medulla Medulla (heart beat etc.)(heart beat etc.)

– Pons Pons (time for bed…wake up!)(time for bed…wake up!)

– Cerebellum Cerebellum (don’t trip… don’t forget to breathe)(don’t trip… don’t forget to breathe)

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Figure 2.6: The BrainstemFigure 2.6: The Brainstem

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MidbrainMidbrain

Contains nerve pathways that connect the Contains nerve pathways that connect the hindbrain with the forebrainhindbrain with the forebrain

Midbrain structures perform important Midbrain structures perform important rolesroles– e.g., control of automatic movements of the e.g., control of automatic movements of the

eye muscleseye muscles Reticular formation plays key role in Reticular formation plays key role in

regulating states of attention, alertness, regulating states of attention, alertness, and arousal.and arousal.

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Major Structures of the Major Structures of the ForebrainForebrain

ThalamusThalamus– Relays sensory information to Relays sensory information to

appropriate parts of the cerebral cortexappropriate parts of the cerebral cortex– Receives input from the basal gangliaReceives input from the basal ganglia

Hypothalamus Hypothalamus – Regulates many vital bodily functions as Regulates many vital bodily functions as

well as emotional states, aggressive well as emotional states, aggressive behavior, and response to stressbehavior, and response to stress

– (The 3 F’s)(The 3 F’s)

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The Limbic SystemThe Limbic System

Group of interconnected structures:Group of interconnected structures:– AmygdalaAmygdala: Helps regulate states of : Helps regulate states of

emotional arousalemotional arousal– HippocampusHippocampus: Plays important role in : Plays important role in

the formation of memoriesthe formation of memories– Why can’t you remember when you Why can’t you remember when you

were born?were born?– Parts of the thalamusParts of the thalamus– Parts of the hypothalamusParts of the hypothalamus

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The Cerebral CortexThe Cerebral Cortex

Thin, outer layer of the largest part Thin, outer layer of the largest part of the forebrain which is called the of the forebrain which is called the cerebrumcerebrum

Cerebrum consists of the right and Cerebrum consists of the right and left cerebral hemispheres.left cerebral hemispheres.– Hemispheres connected by the corpus Hemispheres connected by the corpus

callosumcallosum

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Figure 2.7: The Size of the Figure 2.7: The Size of the Cerebral Cortex in Humans Cerebral Cortex in Humans

and Other Animalsand Other Animals

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Figure 2.8: Lobes of the Figure 2.8: Lobes of the Cerebral CortexCerebral Cortex

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Table 2.1: The Lobes of the Table 2.1: The Lobes of the Cerebral CortexCerebral Cortex

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Figure 2.9: Somatosensory Figure 2.9: Somatosensory Cortex and Motor CortexCortex and Motor Cortex

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Module 2.4Module 2.4Methods of Studying the BrainMethods of Studying the Brain

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MethodologyMethodology

Postmortem studiesPostmortem studies Animal StudiesAnimal Studies Electrical RecordingsElectrical Recordings Static Imaging TechniquesStatic Imaging Techniques Metabolic Imaging Metabolic Imaging

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Recording and Imaging Recording and Imaging TechniquesTechniques

EEG (electroencephalograph)EEG (electroencephalograph) CT (computed tomography) scanCT (computed tomography) scan PET (positron emission tomography) PET (positron emission tomography)

scanscan MRI (magnetic resonance imaging)MRI (magnetic resonance imaging) fMRI (functional MRI)fMRI (functional MRI)

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Experimental MethodsExperimental Methods

LesioningLesioning Electrical recordingElectrical recording Electrical stimulationElectrical stimulation

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Static: Magnetic Resonance Static: Magnetic Resonance ImagingImaging

• Strong magnetic field passed through the skullStrong magnetic field passed through the skull• Uses the detection of radio frequency signals Uses the detection of radio frequency signals

produced by displaced radio waves in a magnetic produced by displaced radio waves in a magnetic field field

• Creates a detailed anatomical image of the brainCreates a detailed anatomical image of the brain

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Metabolic: Positron Metabolic: Positron Emission Tomography Emission Tomography

(PET)(PET) Radioactive material is injected or Radioactive material is injected or

inhaledinhaled Participant is then scanned to produce Participant is then scanned to produce

an image of the brain’s activityan image of the brain’s activity

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Metabolic: fMRIMetabolic: fMRI

fMRI imaging takes a series of images of fMRI imaging takes a series of images of the brain in quick succession and then the brain in quick succession and then statistically analyzes the images for statistically analyzes the images for differences among them differences among them

Brain areas with more blood flow have Brain areas with more blood flow have been shown to have better visibility on fMRI been shown to have better visibility on fMRI images images BOLDBOLD

Better visibility is correlated with brain Better visibility is correlated with brain activationactivation

4949What might this person be doing?

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Module 2.5Module 2.5The Divided Brain: The Divided Brain:

Specialization of FunctionSpecialization of Function

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Lateralization of Brain Lateralization of Brain FunctionsFunctions

Refers to division of functions Refers to division of functions between right and left hemispheresbetween right and left hemispheres– Left hemisphere dominant for language Left hemisphere dominant for language

abilities, logical reasoning, and problem abilities, logical reasoning, and problem solvingsolving

– Right hemisphere dominant in nonverbal Right hemisphere dominant in nonverbal processingprocessing

People are not “left-brained” or People are not “left-brained” or “right-brained.”“right-brained.”

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Figure 2.15: Broca’s and Figure 2.15: Broca’s and Wernicke’s AreaWernicke’s Area

Production

Comprehension

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Broca’s and Wernicke’s AreaBroca’s and Wernicke’s Area

Broca’s Aphasia:Broca’s Aphasia:– Me: How are you today?Me: How are you today?– BA: Ah ah ah ah ah ah ga ga ga ga ga ga BA: Ah ah ah ah ah ah ga ga ga ga ga ga

ga ga gmmmmmmmpppfffffffffff…good ga ga gmmmmmmmpppfffffffffff…good thanksthanks

Wernicke’s Aphasia:Wernicke’s Aphasia:– Me: How are you today?Me: How are you today?– WA: Kangaroos can box you know!WA: Kangaroos can box you know!

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Split-Brain ResearchSplit-Brain Research

Severing corpus callosum as Severing corpus callosum as treatment for severe epilepsytreatment for severe epilepsy

Split-brain patients retain intellect Split-brain patients retain intellect and personalityand personality

But differences in perception, But differences in perception, language evident in special testing language evident in special testing circumstancescircumstances

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Brain Damage and Brain Damage and Psychological FunctioningPsychological Functioning

Case of Case of Phineas GagePhineas Gage: Prefrontal : Prefrontal cortex damagecortex damage

PlasticityPlasticity: Ability of the brain to : Ability of the brain to adapt and reorganize itself following adapt and reorganize itself following trauma or surgical alterationtrauma or surgical alteration

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What happened to Gage?What happened to Gage? ““indulging at times in the grossest indulging at times in the grossest

profanity (which was not previously his profanity (which was not previously his custom), manifesting but little deference custom), manifesting but little deference for his fellows, impatient of restraint or for his fellows, impatient of restraint or advice when it conflicts with his desires “advice when it conflicts with his desires “

CONCLUSION?CONCLUSION? Gage's case is cited as among the first Gage's case is cited as among the first

evidence suggesting that damage to the evidence suggesting that damage to the frontal lobes could alter aspects of frontal lobes could alter aspects of personality and affect socially appropriate personality and affect socially appropriate interaction interaction

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Module 2.7Module 2.7Genes and Behavior: Genes and Behavior:

A Case of Nature and NurtureA Case of Nature and Nurture

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Genetic Influences on Genetic Influences on BehaviorBehavior

Nature-nurture problemNature-nurture problem GenotypeGenotype: An organism’s genetic code: An organism’s genetic code PhenotypePhenotype: The observable physical : The observable physical

and behavioral characteristics of the and behavioral characteristics of the organismorganism

Genetic and environmental influences Genetic and environmental influences interactinteract in complex ways to shape in complex ways to shape our personality.our personality.

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Kinship StudiesKinship Studies

Familial association studiesFamilial association studies Twin studiesTwin studies

– Identical (MZ) vs. fraternal (DZ) twinsIdentical (MZ) vs. fraternal (DZ) twins– Concordance ratesConcordance rates

Adoptee studiesAdoptee studies

Continue

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Figure 2.19: Genetic Overlap Figure 2.19: Genetic Overlap Among Family MembersAmong Family Members