psych neuroscience.ppt

Behavioral Neuroscience

Chapter 2

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Behavioral Neuroscience

• Why study this in psychology?• How can it help us understand the goals of

psychology?• Goals– Describe– Understand– Predict – Control or modify• Behaviors & thoughts

Biology and Behavior

• Behavioral neuroscience– Studies• Relation between biological & psychological

functions

–Can help us understand• Nature of personality• Causes of abnormal behavior• Reaction to stress• Effectiveness of therapy

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Historical View of the Brain

• 1000 BC Egyptian Pharaohs mummification• Brain – Removed & discarded

• Vital to afterlife – Heart • Left in body• Seen as containing perception, cognition & soul

– Intestines, liver, lungs & stomach • Removed, wrapped & placed in canopic jars.

Historical View of the Brain

• Many cultures similar views of heart• Brain interpreted in various ways – Aristotle cooling emotions of heart

• Change began in 1500’s• Leonardo da Vinci 1452-1519– Head seen as holding cognition– Ventricle system • Holes in the brain.

Ventricular System

• Cavities or holes in brain holding cerebrospinal fluid

Mrs. Garrison’s Theory of Evolution

Evolutionary Psychology

• Focuses on–Adapted benefits of selected behaviors• Women –Talk –Multi-task»Women larger area for communication

• Men –Quiet–Singularly focused» Larger area of brain for sex

• Why doesn’t an organism ever achieve perfect adaption?

Evolutionary Psychology

• Why doesn’t an organism ever achieve perfect adaption?–Each adaption has:• Costs?• Benefits?

–Increased head size?

Evolutionary Psychology

Evolution Does :

• Works to improve reproduction success

Evolution Doesn’t:

• Work to improve a species

• Have a conscious plan or purpose

• Work to produce happiness or contentment

Evolution

Evolutionary Psychology

• Natural Selection & Adaptive Behavior– Natural selection• Evolutionary process by which those individuals of a

species that are best adapted are the ones that survive & reproduce

– Survivors better adapted to world than non-survivors

Evolutionary Psychology

Emphasizes importance of AdaptationReproduction“Survival of the fittest”

In shaping behaviorSpatial skills in finding way home

Fit Ability to

Bare offspring that survive long enough to bare offspringPass your genes to next generation

Biology and Behavior

• Scientists who study this:–Represent several disciplines• Psychology (especially physiological

psychologists)• Biology• Medicine• Others

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Neuron

Neurons

• Neurons–Cells that transmit information

• Neurons are composed of:–Dendrites–Soma• Cell Body

–Axon

Neuron Structure

Myelin Sheath

• Myelin Sheath– Composed of glial cells

• (Greek word for “glue”)

– Coats axon of some neurons– White matter of brain– Functions:

• Speeds neurotransmission• Insulates neurons from each other• Makes neurotransmission more efficient• Removes waste• Occupies vacant space when neurons die• Other purposes

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• Myelin–Looks like string of sausages–Doesn’t cover entire length of axon–Nodes of Ranvier• Space between “sausages”• Nerve impulse jumps from 1 node of

Ranvier to next• Transmission up to 100 x’s faster –Unmeylinated axons

Terminal Button

1. Synthesis of neurotransmitter (NT)

2. Storage & transport of NT within vesicles

3. NT Release4. Activation of

postsynaptic receptors5. Termination of

transmitter effect (e.g. reuptake)

Neurotransmitters• Dopamine– Controls arousal levels– Significant role in motor movement– Reward & punishment

• Serotonin – Role in

• Weight regulation• Sleep• Depression• Suicide• obsessive–compulsive disorder• Aggression• Wide range of other disorders & behavior problems.

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• Acetylcholine – Attention– Learning– Memory

• Norepinephrine–Also a hormone–Physical & mental arousal–Heightens mood

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Neurotransmitters

Synapse

• Synapse–Space between axon terminal &

adjacent dendrite or cell body• Neurotransmitter (NT)–Molecules released from terminal

button into synapse.

Neurons: Basic Cells of the Nervous System

• Synapses– Cleared rapidly• So additional signals can be transmitted

• Cleared in 1 of 2 ways, depending on neurotransmitter– 1. breakdown• Broken down & removed

– 2. Reuptake• Recycled back into vesicles

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SSRI Reuptake Inhibitor

• SSRIs block reuptake of serotonin • Called selective – Primarily affect serotonin

• Changes balance of serotonin

SSRI Reuptake Inhibitor

SSRI Reuptake Inhibitor

• Generic names followed by brand names–Citalopram (Celexa)– Escitalopram (Lexapro)– Fluoxetine (Prozac, Prozac Weekly, Sarafem)–Paroxetine (Paxil, Paxil CR, Pexeva)– Sertraline (Zoloft)– Fluoxetine combined with the atypical

antipsychotic olanzapine (Symbyax)

Psychoactive Drugs

• Drugs work in synapse• Agonists enhance neurotransmitter function• Antagonists block neurotransmitter function

Psychoactive Drugs

• Psychoactive drugs–Affect nervous system• Alter mood• Emotion• Thought

– Act by:• Increasing or decreasing release of

neurotransmitters • Stimulating or blocking receptor sites

Opiates

Opiates binding to opiate receptors

• Increased dopamine release

Neurons: Basic Cells of the Nervous System

Presynaptic membrane Side that sends message

Postsynaptic membraneReceiving side of synapse

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Neurons: Basic Cells of the Nervous System

• When electrical signal reaches terminal buttons–Causes vesicles to release a chemical signal• Neurotransmitter into synapse• Contacts postsynaptic membrane (usually

dendrite) of next neuron

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Neurons: Basic Cells of the Nervous System

• Excitation– More likely to transmit the message to

subsequent neurons• Inhibition– Less likely to transmit the message to subsequent

neurons

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Neurons

• Action Potential–Electrical impulse–Causes cells to fire•All or none firing–Like guns fire or don’t fire

Scanning electron microscope picture of a nerve ending broken open to reveal vesicles (orange &

blue) containing neurotransmitters.

Neurons: Basic Cells of the Nervous System

• Most drugs influence operation of neurotransmitter– 1. Agonists• Increase effectiveness–Or

–2. Antagonists• Reduce effectiveness

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