Chapter 3: Biological Psychology Lecture Preview...7 PRS All the synaptic pathways in the human...

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Chapter 3:Chapter 3:Biological PsychologyBiological Psychology

The BrainThe Brain--Body Communication SuperhighwayBody Communication Superhighway

Copyright © Allyn & Bacon 2008

Lecture PreviewLecture Preview

Examine how nerve cells communicate

Review methods for mapping brain functions

Id tif th t f th t ibl f


Identify the parts of the nervous system responsible for sensation, perception, emotion, and motor action

Examine brain development, growth, plasticity, and reorganization

Examine the relationship between the brain the endocrine system and behavior

Neural Communication

Biological Psychology branch of psychology concerned with the links

between biology and behavior

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some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists

The Human Brain

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__________ a nerve cell the basic _________________ of the nervous system

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Sensory Neurons Neurons that send signals from the senses,

skin, muscles, and internal organs to the CNS

Motor Neurons Neurons that transmit commands from the CNS

to the muscles, glands, and organs

Neural CommunicationStructure of a Neuron

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Neurons: Neurons: The Brain’s CommunicatorsThe Brain’s Communicators

Cell body - makes proteins, replenishes l l it l t ll f ti


molecules vital to cell function Separated from outside by neuronal membrane

Neurons cells specialized for communication

____________ – the process of the neuron specialized to receive “information” from adjacent cells (receptor sites, increased surface area/volume yielding enough area for perhaps 10,000 synapses).

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10,000 synapses).

__________ – the process of the neuron specialized for the conduction of the nerve impulse (all or none law), clusters of axons form nerve bundles.

Neuron with a Myelin Sheath


Neural Communication Dendrite the bushy, branching extensions of a neuron that

______________ messages and conduct impulses toward the cell body

Axon

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Axon the extension of a neuron, ending in branching

terminal fibers, through which messages are ______ to other neurons or to muscles or glands

Myelin [MY-uh-lin] Sheath a layer of fatty cells segmentally encasing the fibers of

many neurons enables vastly greater transmission speed of neutral

impulses

Resting Potential

All neurons are _________ or charged cells. More reside inside

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More _________________ reside inside the cell relative to the extracellular fluids. The resting potential is -70 mv. Neurons defend this resting potential.

Ions

Like charged molecules ______ each other. Opposite charged ions attract each other.

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pp g Nature's impulse is to distribute the ions

so that they would become balanced on both sides of the cell membrane. If the ion concentrations were balanced

on both sides of the cell membrane the neuron would no longer be polarized.

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Nerve cells are metabolically expensive

The brain is about 2% of a person's body weight, but it consumes about 20% of the calories we consume every day.

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Neurons are continuously in the process of restoring themselves to their _______________ (-70 mv), and this requires the expenditure of calories.


__________ Potential generated by the movement of positively

charged atoms in and out of channels in the

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axon’s membrane An electrical impulse that surges

along an axon, caused by an influx of positive ions in the neuron


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Cell body end of axon

Direction of neural impulse: toward axon terminals

Voltage Across the Membrane During an Voltage Across the Membrane During an Action PotentialAction Potential


Nerve Impulse

The action potential travels in _____direction Starts at the beginning of the axon (axon

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hillock) Ends at the termination of the axon


Synapse [SIN-aps] junction between the axon tip of the sending

neuron and the dendrite or cell body of the receiving neuron

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receiving neuron tiny gap at this junction is called the synaptic

gap or cleft

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Neurons: Neurons: The Brain’s CommunicatorsThe Brain’s Communicators

Axon - sending portion of neuron

Axon terminal end


Axon terminal - end of axon which contains synaptic _________ with _______________

How neurons communicate

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Synaptic Transmission

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PRS

The flow of activation from one cell to the next (in most portions of the brain) is in one direction only, and cannot be

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reversed.T/F

How neurons communicate

Impulse releases neurotransmitter from axon terminals. Neurotransmitter enters synaptic gap

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Neurotransmitter enters synaptic gap. Neurotransmitter _______________ on

the receiving neuron.

Excitation & Inhibition

Neurotransmitters are released at the axon terminals and they disturb the membrane of the postsynaptic cell so that ions flow across the cell membrane

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the cell membrane. _____________ synapse – the net flow of

ions make the cell less negative or depolarized.

_____________ synapse – the net flow of ions make the cell more negative or hyperpolarized.

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The All or None Law

For the post-synaptic neuron to produce a nerve impulse it must become sufficiently depolarized to reach its ____________

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(about - 40 mv). Excitatory synapses cause the neuron to

become depolarized and shift it towards its threshold. Inhibitory synapses cause the neuron to

become hyperpolarized and shift it away from its threshold.

Number of Synapses?

A typical neuron may have 10,000 synapses contacting the cell body (soma) and dendrites.

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Approximately half the synapses are excitatory, and the other half produce inhibition. The relative activation of these two

contrasting influences determine if the neuron will fire or not.

The balance between inhibition and excitation may shift. Neurons may and become

Neural networks are dynamic

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Neurons may ________ and become slow to restore the resting potential. Neurons may exhaust their supply of

____________________. New receptor sites may be developed.

Drugs & Behavior

Some drugs block the release of neurotransmitters (botox). Some drugs bind to receptor sites and

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Some drugs bind to receptor sites and block their activation by neurotransmitters (Cobra venom). Some drugs disturb the re-uptake or

synthesis of neurotransmitters.


Neurotransmitter molecule

Receiving cellmembrane

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Receptor site onreceiving neuron

Agonist mimicsneurotransmitter

Antagonistblocksneurotransmitter

PRS

High rates of activation of a pre-synaptic neuron always result in high rates of activation in the post-synaptic neuron.

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T/F

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Speed of Neural Conduction

The speed of conduction ranges from 0.5 m/sec to about 100 m/sec.

Thick axons exhibit faster conduction.

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Myelinated axons exhibit faster conduction.

White matter – myelinated axons, grey matter is composed of cell bodies and unmyelinated neurons.

Cooperative Learning

Some portions of the brain do not become myelinated until a child becomes 5-6 years of age. M t ith t d b d

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Meet with your study group members and discuss how a child’s behavior may likely differ due to the presence or absence of myelin. You have 60 seconds.

Glial Cells: Supporting RolesGlial Cells: Supporting Roles

Glia - support cells of the nervous system

Form myelin sheath covering of axons


Form myelin sheath covering of axons Form blood-brain barrier to protect the brain Respond to injury Remove debris

Neurotransmitters

Different pathways in the brain may use different _______________.

Sending neurons “classically” always release the same neurotransmitter.

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Receiving neurons may have synapses from different pathways employing different neurotransmitters.

Over 100 neurotransmitters have been discovered in the brain, and it is likely that many new ones will be discovered.

Serotonin Pathways

Serotonin pathways are involved with mood

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regulation.

Dopamine Pathways

Dopamine pathways are involved with

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are involved with diseases like

schizophrenia and Parkinson’s disease.

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PRS

All the synaptic pathways in the human brain use the same neurotransmitter.T/F

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PRS

The speed of transmission of a nerve impulse is dependent upon the presence (or absence of myelin), and the diameter

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of the axon.T/F

Cooperative Group ChallengeThe Rules

Left Group vs. Right Group All the members of each group receive

bonus points for each question the group p q g panswers correctly. The group (left or right) that answers the

most questions correctly wins additional bonus points.

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Cooperative Group Challenge

1. blood-brain barrier 2. dendrite 3. axon 4. synaptic vesicles 5. synaptic cleft 6. cell body 7. myelin sheath 8. resting potential

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Q1. The central region of the neuron which manufactures new cell components is called the _____.

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Q2. The receiving ends of a neuron extending from the cell body like a tree branch are called the _____.

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Q3. The space between two connecting neurons where neurotransmitters are released is called the _____.

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Q4. _____ are long extensions from the cell body of the neuron that transmit messages from one neuron to another.

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Q5. _____ small spheres within the axon that contain chemical messages specialized for communication.

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Q6. The brain’s ability to protect itself from infection and high hormone levels is through the _____.

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Q7. The autoimmune disease multiple sclerosis is linked to the destruction of the glial cells wrapped around the axon –called the _____.

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Q8. The electrical charge difference measured across the membrane of a neuron when it is not being stimulated is called the _____.

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Schizophrenia and Neurotransmitters

Stein and Wise Norepinephrine Theory Deficit in ________ directed thinking. Deficit in the capacity to experience

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Deficit in the capacity to experience _______________. A pathological gene leads to the reduction

in the synthesis of a brain enzyme dopamine-B-hydroxylase (DBH) which converts dopamine into norepinephrine.

Stein & Wise

These affected fibers release __________ at the synapse instead of norepinephrine.

There is too much dopamine in the brain. Some of the excess dopamine is converted

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Some of the excess dopamine is converted extracellulary into 6-hydroxydopamine (6-OH-DA).

6-OH-DA is a neurotoxin that selectively destroys adjacent norepinephrine synapses that are still healthy.

Evidence

Schizophrenia exhibits a heritable factor. Brains of schizophrenics show a reduction in

the level of the DBH enzyme. 6-OH-DA abolishes brain

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6 OH DA abolishes brain ________________. 6-OH-DA induces _________________. 6-OH-DA is linked to the production of

unusual body odor. 6-OH-DA may be converted into a

hallucinogen (2-hydroxy 4,5 dimethoxyphenethanolamine).

Schizophrenia

Other researchers believe that schizophrenia is associated with excess dopamine, but it may not involve the

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p , ynorepinephrine pathway. Schizophrenia is a complicated disorder,

different patients exhibit different symptoms, and different mechanisms may account for the variability in symptoms between patients.

PRS

Schizophrenia is believed to be due to an imbalance in one or more neurotransmitters.

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T/F

The Nervous System Nervous System the body’s speedy, electrochemical

communication system consists of all the nerve cells of the peripheral

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consists of all the nerve cells of the peripheral and central nervous systems

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The Nervous System

__________ Nervous System(CNS) The network of nerves contained

within the brain and spinal cord

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p

__________ Nervous System(PNS) The PNS comprises the somatic and

autonomic nervous systems

The Nervous System

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The Nervous System

Nerves neural “cables” containing many axons part of the peripheral nervous system

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connect the central nervous system with muscles, glands, and sense organs

Sensory Neurons neurons that carry incoming information from

the sense receptors to the central nervous system

The Nervous System

Interneurons CNS neurons that internally communicate and

intervene between the sensory inputs and motor outputs

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Motor Neurons carry outgoing information from the CNS to

muscles and glands Somatic Nervous System the division of the peripheral nervous system

that controls the body’s skeletal muscles

The Autonomic Nervous SystemThe Autonomic Nervous System

__________ division - active during emotional arousal; activates fight-or-flight responses


_______________ division - active during rest and digestion

Work in opposition to each other: when one is active, the other is passive

The Autonomic Nervous System: The Autonomic Nervous System: Sympathetic and Parasympathetic BranchesSympathetic and Parasympathetic Branches


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PRS

The CNS is that portion of the nervous system housed within the skull and spinal cord.

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T/F

The Brain

Lesion tissue

destruction

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destruction a brain lesion is

a naturally or experimentally caused destruction of brain tissue

BrainBrain--Mapping MethodsMapping Methods

3. Electrical stimulation and recording of the nervous system EEG


4. Brain scansa. CT and MRI - structural imagingb. PET and fMRI - functional imaging

5. Magnetic stimulation and recordinga. Transcranial Magnetic Stimulation (TMS)b. Magnetoencephalography (MEG)

Electroencephalogram (EEG)

an amplified recording of the waves of electrical activity that sweep

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activity that sweep across the brain’s surface these waves are

measured by electrodes placed on the scalp

Tools of Behavioral NeuroscienceElectroencephalogram (EEG)

An instrument used to measure electrical activity

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in the brain through electrodes placed on the scalp

The Brain CT (computed tomography) Scan a series of x-ray photographs taken from different angles

and combined by computer into a composite representation of a slice through the body; also called CAT scan

PET ( it i i t h ) S

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PET (positron emission tomography) Scan a visual display of brain activity that detects where a

radioactive form of glucose goes while the brain performs a given task

MRI (magnetic resonance imaging) a technique that uses magnetic fields and radio waves to

produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain

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PET Scan

Radioactive isotopes (small amounts) are placed in the

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blood.Sensors detect radioactivity.Different tasks show distinct activity patterns.

MRI ScanMRI (magnetic resonance imaging) uses magnetic fields and radio waves to

produce computer‐generated images that

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generated images that distinguish among

different types of brain tissue. Top images show ventricular enlargement in a schizophrenic patient.

Bottom image shows brain regions when a participants lies.

Central Nervous System

______ brains, one on the left and one on the right. Brain structures were named for

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Brain structures were named for familiar objects Cortex – tree bark Cerebellum – little brain Pons – bridge Thalamus – inner chamber

Regions of the Brain

Cerebral Cortex Limbic System Brain Stem

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Brain Stem

R i

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Regions of the Brain

The Four Lobes of the Cerebral Cortex

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The Forebrain (_________ Cortex)The Forebrain (_________ Cortex)

1. Cerebral Cortex -outermost covering,

contains: Neocortex most recently


Neocortex - most recently developed cortex

Cerebral hemispheres -left and right

Corpus callosum -connects the two hemispheres

The Forebrain (Cerebral Cortex)The Forebrain (Cerebral Cortex)

2. ________ Lobe - Motor cortex - sends

signals to muscles Prefrontal cortex


Prefrontal cortex -executive functions Injury: Broca’s area &

aphasia Phineas Gage &

personality change

The Forebrain (Cerebral Cortex)The Forebrain (Cerebral Cortex)

3. ____________ Lobe -perception of space, object shape and orientation, actions of others, numbers

Integrates vision touch


– Integrates vision, touch, motor information

Somatosensory cortex -pressure, temperature, pain

Injury: acalculia, contralateral neglect

Representation of the Body Mapped onto the Motor and Sensory Areas of Representation of the Body Mapped onto the Motor and Sensory Areas of the Cerebral Cortexthe Cerebral Cortex


The Forebrain (Cerebral Cortex) The Forebrain (Cerebral Cortex)

4. ___________ Lobe -hearing, language comprehension, autobiographical memories


autobiographical memories

Auditory cortex Injury: Wernicke’s area and

aphasia

The Forebrain (Cerebral Cortex) The Forebrain (Cerebral Cortex)

5. _____________ Lobe -vision Visual cortex

Sensory Cortical Hierarchies


Sensory Cortical Hierarchies

Sensory info(e.g., light)

Association Cortex (e.g., conscious perception of visual scene)

Sensory cortex(e.g., visual ctx)

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Selected Areas of the Cerebral CortexSelected Areas of the Cerebral Cortex


PRS

The frontal lobe is responsible for visual perception. T/F

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The Limbic SystemThe Limbic System


The Brain and EmotionThe Brain and Emotion

________ system - emotional center of the brain networked with the autonomic nervous


networked with the autonomic nervous system to influence blood pressure, heart and the endocrine system, etc. Information about our internal state

The Brain and Emotion:The Brain and Emotion:Limbic CircuitsLimbic Circuits

1. Hypothalamus - maintains internal bodily states by overseeing the endocrine and autonomic nervous systems


(e.g., releases hormones to influence hunger, sexual motivation)

2. Amygdala - excitement, arousal, fear, social signals related to emotion

Hypothalamus neural structure lying

below (hypo) the thalamus; directs several maintenance activities eating drinking body temperature

helps govern the endocrine system via the __________ gland is linked to emotion

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The Brain and Emotion:The Brain and Emotion:Limbic CircuitsLimbic Circuits

3. Cingulate Cortex - active during emotional expression– knowledge of socially appropriate behavior


– regulates autonomic nervous system

4. Hippocampus - spatial memory (e.g., place cells), fear conditioningInjury: problem forming new

memories

The Limbic System

Electrode implanted in reward

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reward center

PRS

The limbic system is involved in regulation of affect and emotion. T/F

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BrainstemBrainstem


The Brainstem

Medulla Vital involuntary

functions Pons

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Sleep and arousal Reticular formation Sleep, arousal,

attention Cerebellum Motor coordination

Cerebellum

Cerebellum [sehr-uh-BELL-um]

the “little brain” the “little brain” attached to the rear of the brainstem it helps coordinate

voluntary movement and balance

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The Brain

Brainstem the oldest part and central core of the brain,

beginning where the spinal cord swells as it

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g g penters the skull responsible for ________________ functions

Medulla [muh-DUL-uh] base of the brainstem controls heartbeat and breathing

The Cerebral Cortex

Neocortex regulates reading, talking, problem solving.

Subcortical regions regulate sleep, thermoregulation and other vegetative

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g gprocesses.

Paradox: the functions of the neocortex which define us as unique individuals are ____________, during a trauma, such as lack of oxygen, blood flow is shunted away from the neocortex to preserve subcortical structures.

PRS

The brainstem is responsible for high level cognitive processes.T/F

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Specialization and Integration

Brain activity when hearing, seeing, and speaking words

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Language Processing _______ Area Located in the

left hemisphere, directs the muscle

t i

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movements in speech production

Wernicke’s Area Located in the

left hemisphere, involved in the comprehension of language

The Cerebral Cortex

Broca’s Area an area of the left frontal lobe that directs the

muscle movements involved in speech

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___________ Area an area of the left temporal lobe involved in

language comprehension and expression

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The Cerebral Cortex

Aphasia impairment of language, usually caused by left

hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area

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(impairing speaking) or to Wernicke s area (impairing understanding)

PRS

For most individuals the left hemisphere is dominant for language processing. T/F

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Textbook Assignment 3-3.

Complete the assess your knowledge assignment on page 146. __________________________________

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__________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________

Brain Reorganization

_________ the brain’s capacity for

difi ti id t i b i

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modification, as evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development

Brain Changes During Development Brain Changes During Development and Experienceand Experience

Neural plasticity - the nervous system’s ability to ___________:

1. Before birth and until maturation is complete (early adulthood) Cell division migration


(early adulthood). Cell division, migration, connections:

a. Growth of dendrites and axonsb. Synaptogenesisc. Pruningd. Myelination

2. During learning: Long-Term Potentiation (LTP), enriched environments

Neural PlasticityNeural Plasticity


Early Brain Development

Increased branching of dendrites with enrichment

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Neural Plasticity Neural Plasticity (cont’d)(cont’d)

3. Following Injury and Degeneration

4. Stem Cells: cells that have potential to b i t f i li d ll


become a variety of specialized cells

5. Neurogenesis: production of new neurons in the adult brain

Plasticity

Richer environments lead to heavier, thicker brains, more synapses, and better learning.

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The cost of plasticity is the case of the phantom limb.

Living life to the full, the girl with only half a brain takes her first steps.

She was suffering from an incurable genetic condition for which the only possible hope was to have half her brain

d

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removed.

Doctors warned her parents that their daughter would never walk, talk, cry or smile like a normal child - even if she survived.

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Cooperative Learning

In some cases enormous amounts of brain tissue may be removed with “acceptable” or minimal negative consequences, in other instances a modest amount of brain damage

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instances a modest amount of brain damage produces enormous effects.

Meet with your group and discuss why the outcomes are so different in these cases.

You have 60 seconds.

Answer

__________________________________ __________________________________ __________________________________

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__________________________________ __________________________________ __________________________________ __________________________________ __________________________________

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Splitting the BrainA procedure in which the two hemispheres of

the brain are isolated by cutting the _________ __________ (mainly those of the corpus

callosum) between them.Corpus CallosumC Corpus Callosum

Martin M

. Rother

Courtesy of Terence W

illiams, U

niversity of Iowa

Corpus Callosum

A bundle of nerve fibers that connects the left and right h i h

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hemispheres

If surgically severed for treatment of epilepsy, hemispheres cannot communicate directly.

Split Brain Patients The information

highway from the eye to the brain

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With the corpus callosum severed, objects (apple) presented in the right visual field can be named. Objects (pencil) in the left visual field cannot.

Textbook Assignment 3-3. Which object would you perceive when these two words are flashed to different hemispheres? Which object would a split-brain subject perceive? Submit your answers to your TA.

Sperry’s Split Brain Experiment

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Split-brain subjects could not name objects shown only to the right hemisphere.

If asked to select these objects with their left hand, they succeeded.

The left hemisphere controls speech, the right does not.

Brain Functioning

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PRS

Surgically isolation of the left and right hemispheres is sometimes performed to reduce the severity of epileptic seizures.

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T/F

The Endocrine System:The Endocrine System:Hormonal RegulationHormonal Regulation

1. Pituitary gland -“master gland” controls other bodily


glands and is under control of the ___________

Hierarchy of Control over the Endocrine System


The Endocrine SystemThe Endocrine System

2. Adrenal glands - release adrenaline and cortisol during physical and psychological stress


– activated by the sympathetic nervous system

The Endocrine SystemThe Endocrine System

3. Sexual reproductive glandsTestes in males produce testosteroneOvaries in females produce estrogen


Ovaries in females produce estrogen

However, both sexes release some sex hormone associated with the opposite sex

Endocrine System

Hormones are like a neurotransmitter that are distributed to receptor sites via the __________ supply. Hormones orchestrate and coordinate

i di b f

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responses in a diverse number of structures. _______ delay between release of the

hormone and the response, and a ____ return to baseline.

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PRS

The neurotransmitter and endocrine system work together to coordinate behavioral responses.

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T/F

Stress Responses The sympathetic branch of the autonomic

nervous system innervates the adrenal gland and causes the release of adrenalin.

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Neurons from the hypothalamus innervate the pituitary gland and cause the release of ACTH, and this hormone causes the adrenal gland to release three additional hormones involved in the body’s stress response.

Stress Responses Pupils dilate, blood pressure increases, heart

rate increases, muscles tense, digestion is terminated, catabolic processes required for the _____ __________ of energy are

ti ted

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activated. Because the endocrine system is sluggish

(slower to start and stop) emotions and feeling’s of the body’s response continue after the emergence is resolved.

PRS

Behavioral responses strongly influenced by the endocrine system are relatively slow to start and to return to baseline.

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T/F

Chapter 3: Biological Psychology Lecture Preview...7 PRS All the synaptic pathways in the human...

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