Chapter 2 Lecture Powerpoint Myers Ed. 10

7/29/2019 Chapter 2 Lecture Powerpoint Myers Ed. 10

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PowerPointPresentation

by Jim Foley

2013 Worth Publishers

Chapter 2The Biology

of Mind


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Surveying the Chapter: OverviewWhat We Have in Mind

Building blocks of the mind: neuronsand how they communicate(neurotransmitters)

Systems that build the mind: functionsof the parts of the nervous system

Supporting player: the slower-communicating endocrine system(hormones)

Star of the show: the brain and itsstructures


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Searching for the self by studying the body

Phrenology

Phrenology yielded one big idea--that the brain might havedifferent areas that do differentthings (localization of function).

Phrenology(developed by Franz Gall in

the early 1800s):

the study of bumps on the

skull and their relationshipto mental abilities andcharacter traits


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Biological psychologyincludes neuroscience,behavior genetics,neuropsychology, andevolutionary psychology.

All of thesesubspecialties exploredifferent aspects of:how the nature of mindand behavior is rooted in

our biological heritage. Our study of the biology

of the mind begins withthe atoms of the mind:neurons.

Todays search for the biology of the self:

biological psychology


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Neurons and Neuronal Communication:The Structure of a Neuron

There are billions of neurons

(nerve cells) throughout the body.


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Action potential:a neural impulse that travels down an

axon like a waveJust as the wave can flow tothe right in a stadium eventhough the people only moveup and down, a wave movesdown an axon although it is

only made up of ion exchangesmoving in and out.


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The neuronreceives

signals fromother

neurons;

some aretelling it tofire and someare telling itnot to fire.

When thethreshold isreached, theaction potentialstarts moving.

Like a gun, iteither fires or itdoesnt; morestimulation doesnothing.

This is known asthe all-or-

none response.

The actionpotential

travels downthe axon

from the cellbody to theterminal

branches.

The signal istransmittedto another

cell.However, the

messagemust find away to cross

a gapbetweencells. Thisgap is also

called thesynapse.

How neurons communicate

(with each other):

When does the cell sendthe action potential?...

when it reaches athreshold

The threshold is reached whenexcitatory (Fire!) signalsoutweigh the inhibitory (Dontfire!) signals by a certain amount.


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The synapse isalso known as thesynapticjunction orsynaptic gap.

The SynapseThe synapse is ajunction between theaxon tip of thesending neuron andthe dendrite or cellbody of the receivingneuron.


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Neurotransmitters

Neurotransmittersare chemicalsused to send asignal across thesynaptic gap.


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Reuptake:

Recycling Neurotransmitters [NTs]

Reuptake:After the neurotransmittersstimulate the receptors on

the receiving neuron, thechemicals are taken back upinto the sending neuron tobe used again.


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Seeing all the Steps TogetherNeural Communication:


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Some Neurotransmitters and Their Functions

Neurotransmitter Function Problems Caused by Imbalances

Roles of Different Neurotransmitters

Serotonin Affects mood, hunger,sleep, and arousal

Undersupply linked to depression;some antidepressant drugs raiseserotonin levels

Dopamine Influences movement,

learning, attention, andemotion

Oversupply linked to schizophrenia;

undersupply linked to tremors anddecreased mobility in Parkinsonsdisease and ADHD

Acetylcholine(ACh)

Enables muscle action,learning, and memory

ACh-producing neurons deteriorate asAlzheimers disease progresses

Norepinephrine Helps control alertness

and arousal

Undersupply can depress mood and

cause ADHD-like attention problems

GABA (gamma-aminobutyric acid

A major inhibitoryneurotransmitter

Undersupply linked to seizures,tremors, and insomnia

Glutamate A major excitatoryneurotransmitter;involved in memory

Oversupply can overstimulate the brain,producing migraines or seizures; this iswhy some people avoid MSG(monosodium glutamate) in food


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Serotoninpathways

Networks of neurons thatcommunicate with serotoninhelp regulate mood.

Networks of neurons that

communicate with dopamine areinvolved in focusing attentionand controlling movement.

Dopaminepathways


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Hearing the message

How Neurotransmitters ActivateReceptors

When thekey fits,the site is

opened.


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Keys that almost fit:Agonist and AntagonistMolecules

An antagonist moleculefills the lock so that theneurotransmitter cannotget in and activate thereceptor site.

An agonistmolecule fillsthe receptor site andactivates it, acting like theneurotransmitter.


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The Inner and Outer Parts of theNervous System

The centralnervoussystem[CNS]consists ofthe brainand spinalcord.

The CNS

makesdecisionsfor thebody.

Theperipheralnervoussystem [PNS]consists of

the rest ofthe nervoussystem.

The PNSgathers and

sendsinformationto and fromthe rest ofthe body.


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Types of Neurons

Sensory

neurons carrymessages INfrom the

bodys tissuesand sensory

receptors tothe CNS forprocessing.

Motorneurons carryinstructions

OUT from theCNS out to thebodys tissues.

Interneurons(in the brainand spinal

cord) processinformationbetween thesensory input

and motor

output.

Th N


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The Nervesare not the same as neurons.

Nerves consist ofneural cablescontaining manyaxons.

Nerves are part ofthe peripheralnervous system andconnect muscles,

glands, and senseorgans to thecentral nervoussystem.


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More Parts of the Nervous System


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The Peripheral Nervous System

Th


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TheAutonomic

NervousSystem:

The sympathetic

NS arouses(fight-or-flight)

Theparasympathetic

NS calms(rest and digest)


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The Central Nervous System

The brain is a web ofneural networks.

The spinal cord is full ofinterneurons thatsometimes have a mindof their own.


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Neural Networks

These complex webs of interconnected

neurons form with experience.Remember:

Neurons that fire together, wire together.


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Interneurons in the SpineYour spines

interneurons triggeryour hand to pullaway from a firebefore you can sayOUCH!

This is an exampleof a reflex action.


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The Endocrine System

The endocrine systemrefers to a set of glands that

produce chemicalmessengers calledhormones.

Th B d Sl b t S


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The Bodys Slow but SureEndocrine Message System The endocrine

system sendsmolecules asmessages,just likethe nervous system,but it sends them

through thebloodstream insteadof across synapses.

These molecules,called hormones,

are produced invarious glandsaround the body.

The messages go tothe brain and other

tissues.

d h h


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1. The sympatheticfight or flightnervous systemresponds to stressby sending amessage toadrenal glands torelease thehormones listedabove.

2. Effect: increasedheart rate, bloodpressure, andblood sugar. Theseprovide ENERGYfor the fight orflight!

Adrenal Glandsproduce hormones such asadrenaline/epinephrine,noradrenaline/norepinephrine, andcortisol.

Pancreas

Adrenal Glands

h l d


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The Pituitary Gland

The pituitary gland is the

master gland of theendocrine system. It is controlled through

the nervous system by thenearby brain area--the

hypothalamus. The pituitary gland

produces hormones thatregulate other glandssuch as the thyroid.

It also produces growthhormone (especiallyduring sleep) andoxytocin, the bondinghormone.

Pituitary gland


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The Brain

What well discuss: how we learn about the brain the life-sustaining inner parts of the

brain: the brainstem and limbic system the outer, wrinkled bark: the cortex left, right, and split brains

Questions about parts of the brain: Do you think that the brain is the

sum of its parts, or is the brainactually about the way they areconnected?

What do you think might happenif a particular area of the brainwas stimulated?

What do you think might happenif a particular area of the brainwas damaged or not working

well?

Is it possible tounderstand the brain?

If the human brain wereso simple that we couldunderstand it, we would

be so simple that wecouldnt.

Emerson M. Pugh

but we can try.


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Investigating theBrain and Mind:How did we move beyondphrenology?How did we get inside theskull and under thebumps?

by finding what happenswhen part of the brain isdamaged or otherwiseunable to work properly

by looking at thestructure and activity ofthe brain: CAT, MRI,fMRI, and PET scans

Strategies for finding outwhat is different about themind when part of the

brainisnt workingnormally:

case studies ofaccidents(e.g. Phineas Gage)

case studies of split-brain

patients (corpus callosumcut to stop seizures) lesioning brain parts in

animals to find out whathappens

chemically numbing,magnetically deactivating,or electrically stimulatingparts of the brain


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Studying cases of brain damage

When a stroke or injury damages part of the brain, wehave a chance to see the impact on the mind.

I t ti l b i d


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Intentional brain damage:

performed on animals

has yielded someinsights, especiallyabout less complexbrain structures

no longer necessary, as

we now can chemicallyor magneticallydeactivate brain areasto get similarinformation

Lesions (surgical

destruction of braintissue)


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Split-Brain Patients

Split = surgery inwhich theconnection betweenthe brainhemispheres is cut

in order to endsevere full-brainseizures

Study of split-brainpatients has yielded

insights discussed atthe end of thechapter


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Monitoring activity in the brain

Tools to read electrical, metabolic, and magneticactivity in the brain:

EEG:electroencephalogram

MRI: magneticresonance imaging

fMRI: functional MRI

PET: positron emissiontomography


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An EEG (electroencephalogram)is a recording of the electricalwaves sweeping across the

brains surface.An EEG is useful in studyingseizures and sleep.

EEG:electroencephalogram


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The PET scan allows us to see whatpart of the brain is active bytracing where a radioactive form

of glucose goes while the brainperforms a given task.

PET: positron emissiontomography


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MRI (magnetic resonance imaging)makes images from signals produced bybrain tissue after magnets align the spinof atoms.

The arrows below show ventricularenlargement in a schizophrenic patient(right).

MRI: magneticresonance imaging

Functional MRI revealsbrain activity andfunction rather thanstructures.

Functional MRIcompares successiveMRI images taken asplit second apart, andshows changes in the

level of oxygen inbloodflow in the brain.

fMRI: functional MRI


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Areas of the brain and their functions

The brainstemand cerebellum:

coordinatesthe body

The limbic(border) system:

managesemotions, andconnectsthought to

body

The cortex (theouter covering):

integratesinformation

Th B i
http://www.youtube.com/watch?v=snO68aJTOpMhttp://www.youtube.com/watch?v=snO68aJTOpM


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The Brain:Less Complex Brain Structures

Our tour of the brain begins with parts of the human

brain found also in simpler animals; these partsgenerally deal with less complex functions:

Brainstem (Pons and Medulla)

Thalamus

Reticular Formation

Cerebellum

Limbic System
http://www.youtube.com/watch?v=snO68aJTOpMhttp://www.youtube.com/watch?v=snO68aJTOpM


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The Brainstem:

Pons and Medulla


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The Base of theBrainstem:

The Medulla

The medulla controls the most basic functionssuch as heartbeat and breathing.

Someone with total brain damage above themedulla could still breathe independently, butsomeone with damage in this area could not.


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TheBrainstem:

The Pons

The pons helpscoordinate automaticand unconsciousmovements.


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The Thalamus (Inner Chamber)

The thalamus is thesensory switchboard orrouter.

All sensory messages,except smell, are routedthrough the thalamus onthe way to the cortex(higher, outer brain).

The thalamus also sendsmessages from the cortexto the medulla andcerebellum.

R i l (N lik ) F i


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Reticular (Netlike) Formation

The reticular formation is anerve network in thebrainstem.

It enables alertness,(arousal) from coma towide awake (asdemonstrated in the catexperiments).

It also filters incomingsensory information.


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The cerebellumhelps coordinatevoluntarymovement such as

playing a sport.

Cerebellum(little brain)

The cerebellum has many otherfunctions, including enablingnonverbal learning and memory.

The Limbic (Border) System


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emotions such as fear andaggression.

basic drives such as hungerand sex.

the formation of episodicmemories.

The hippocampus

(seahorse) processes conscious,

episodic memories. works with the amygdala

to form emotionallycharged memories.

The Amygdala (almond) consists of two lima bean-

sized neural clusters. helps process emotions,

especially fear and

aggression.

The Limbic ( Border ) SystemThe limbic system coordinates:


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The Amygdala

Electricalstimulation of acats amygdalaprovokes aggressive

reactions. If you move the

electrode veryslightly and cage

the cat with amouse, the cat willcower in terror.

The Hypothalamus:


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lies below (hypo) thethalamus.

regulates body temperature andensures adequate food andwater intake (homeostasis), andis involved in sex drive.

directs the endocrine system viamessages to the pituitary gland.

The Hypothalamus:Thalamus

Riddle: Why did the ratcross the grid?

Why did the rat want toget to the other side?

The Hypothalamus as a Reward Center

Pushing the pedal thatstimulated the electrodeplaced in thehypothalamus was muchmore rewarding than food

pellets.

R i f B i St t


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Review of Brain Structures

The Cerebral Cortex


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The Cerebral CortexThe lobes consist of:

300 billion synaptic

connections

The brain hasleft and right

hemispheres

outer grey bark structure that is wrinkled in order tocreate more surface area for 20+ billion neurons.

inner white stuffaxonslinking parts of the brain. 180+ billion glial cells, which feed and protect neurons

and assist neural transmission.

The Lobes of the Cerebral Cortex:


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The Lobes of the Cerebral Cortex:Preview

Frontal Lobes

Parietal Lobes

Occipital Lobes

Temporal Lobes

involved in speaking andmuscle movements and inmaking plans and judgments

include the sensory cortex

include the visual areas;they receive visualinformation from theopposite visual field

include the auditoryprocessing areas

F ti f th B i


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Input: Sensorycortex (Lefthemispheresection receivesinput from thebodys right side)

Output: Motorcortex (Lefthemispheresectioncontrols thebodys rightside)

Functions of the Brain:

The Motor and Sensory Strips

Axonsreceiving motorsignals FROMthe cortex

Axonssendingsensory

information

TO the cortex

Using our knowledge of functions:


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Using our knowledge of functions:

Brain-computer interfaces

and neural prosthetics Here, a robotic arm is

operated through

controls embedded inthe motor strip of thecortex.

We may soon be able to

use computers totranslate neural inputsinto more commandsand words than simplygrabbing food.


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Sensory Functions of the Cortex

Thesensory stripdealswith information fromtouch stimuli.

The occipital lobe dealswith visualinformation.

Auditoryinformation is

sent to thetemporallobe.

The Visual Cortex


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The Visual Cortex

This fMRI scanshowsincreasedactivity in thevisual cortexwhen a personlooks at aphotograph.

A i ti f ti f th t


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Association function of the cortex

More complex animals have more cortical spacedevoted to integrating/associating information

Association Areas


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Association Areas:

Frontal Lobes

The frontal lobes areactive in executivefunctions such asjudgment, planning, and

inhibition of impulses. The frontal lobes are also

active in the use ofworking memory and the

processing of newmemories.

Phineas Gage (1823 1860)


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Phineas Gage (1823-1860)

Case study: In a work accident, ametal rod shot up through PhineasGages skull, destroying his eye andpart of his frontal lobes.After healing, he was able to functionin many ways, but his personalitychanged; he was rude, odd, irritable,and unpredictable.

Possible explanation:

Damage to the frontal lobes couldresult in loss of the ability to suppressimpulses and to modulate emotions.

Parietal Lobe Association Areas
https://vimeo.com/album/2510733/video/42123884


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Parietal Lobe Association Areas

This part of the brain has many functions in the

association areas behind the sensory strip: managing input from multiple senses

performing spatial and mathematical reasoning

monitoring the sensation of movement

Temporal Lobe Association Areas


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Temporal Lobe Association Areas

Some abilities managed by association areas in this bythe temples lobe:

recognizing specific faces

managing sensory input related to sound, which helps

the understanding of spoken words

Whole brain Association Activity


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Whole-brain Association Activity

Whole-brain associationactivity involves complexactivities which requirecommunication amongassociation areas across thebrain such as:

memory

language

attention

meditation and spirituality

consciousness

Specialization and Integration


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Specialization and IntegrationFive steps in reading a word aloud:

Plasticity: The Brain is Flexible
https://vimeo.com/album/2510733/video/51076630https://vimeo.com/album/2510733/video/51076630


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This 6-year-old had ahemispherectomy to end life-threatening seizures; herremaining hemispherecompensated for the damage.

Plasticity: The Brain is Flexible

If the brain is damaged,especially in the generalassociation areas of thecortex: the brain does not

repair damagedneurons, BUT it canrestore some functions

it can form newconnections, reassign

existing networks, andinsert new neurons,some grown from stemcells
https://vimeo.com/album/2510733/video/51076630https://vimeo.com/album/2510733/video/51076630


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Our Two

Hemispheres

Lateralization (going to one side)The two hemispheres serve some different functions.How do we know about these differences? Brain damage studies revealed many functions of

the left hemisphere. Brain scans and split brain studies show more aboutthe functions of the two hemispheres, and how theycoordinate with each other.

The intact but lateralized brain


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Thoughts and logic

Details such as trees

Language: words and

definitions

Linear and literal

Calculation

Pieces and details

Feelings and intuition

Big picture such as forest

Language: tone, inflection,

context

Inferences and associations

Perception

Wholes, including the self

Right-Left Hemisphere Differences

Left Hemisphere Right Hemisphere


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Brain Studies

Researchers have studied theimpact of this surgery onpatients functioning.

Split-

To end severe

whole-brainseizures, somepeople have hadsurgery to cut thecorpus callosum,

a band of axonsconnecting thehemispheres.

Separating the Hemispheres:


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p g pFactors to Keep in Mind

Each hemisphere controls the opposite side ofthe body AND is aware of the visual field on

that opposite side.

Without the corpus callosum, the halves ofthe body and the halves of the visual field do

not work together.

Only the left half of the brain has enoughverbal ability to express its thoughts out loud.

S lit i l fi ld


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Split visual field

Each hemisphere doesnot perceive what eachEYE sees. Instead, itperceives the half of the

view in front of you thatgoes with the half of thebody that is controlledby that hemisphere.

Divided Awareness in the Split Brain


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Divided Awareness in the Split Brain

Try to explain the following result:

The divided brain in action
http://www.youtube.com/watch?v=ZMLzP1VCANohttp://www.youtube.com/watch?v=ZMLzP1VCANo


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The divided brain in action

Talent: peopleare able tofollow twoinstructions anddraw two

different shapessimultaneously Drawback:

people can befrustrated that

the right and leftsides dodifferent things
http://www.youtube.com/watch?v=ZMLzP1VCANohttp://www.youtube.com/watch?v=ZMLzP1VCANo

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