AP Psych Agenda9.28.10

The Biological Basis of BehaviorMike/Bob scenarioFirst assignment: working with a partner (or

alone if you’d prefer), create a lesson plan geared to an 8th grade class that teaches the students the important concepts behind neurons.Make a list of concepts that must be coveredMake a drawing of a synapse that includes:

1. One complete neuron (axon, dendrite, soma)2. A post synaptic dendrite

Prepare an explanation of a synapse that a 13 yr-old would understand

Build-a-Brain project due next Friday, October 8th. (directions given today)

Chapter 3: The Biological Bases of Behavior

Communication in the Nervous System

Hardware:Glia – structural support and insulationNeurons – communicationSoma – cell bodyDendrites – receiveAxon – transmit away

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Neuron and Neural Impulse

Figure 3.1 Structure of the neuron

Neural Communication:Insulation and Information Transfer

Myelin sheath – speeds up transmissionTerminal Button – end of axon; secretes

neurotransmittersNeurotransmitters – chemical messengersSynapse – point at which neurons

interconnect

The Neural Impulse:Electrochemical Beginnings

Hodgkin & Huxley (1952) - giant squidFluids inside and outside neuron Electrically charged particles (ions)Neuron at rest – negative charge on inside

compared to outside-70 millivolts – resting potential

The Neural Impulse: The Action PotentialStimulation causes cell membrane to open

brieflyPositively charged sodium ions flow inShift in electrical charge travels along

neuronThe Action Potential All – or – none law

Figure 3.2 The neural impulse

The Synapse: Chemicals as Signal CouriersSynaptic cleftPresynaptic neuron

Synaptic vesiclesNeurotransmitters

Postsynaptic neuronReceptor sites

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Synaptic Transmission

Figure 3.3 The synapse

When a Neurotransmitter Binds:The Postsynaptic Potential

Voltage change at receptor site – postsynaptic potential (PSP)Not all-or-noneChanges the probability of the postsynaptic

neuron firingPositive voltage shift – excitatory PSPNegative voltage shift – inhibitory PSP

Figure 3.4 Overview of synaptic transmission

Signals: From Postsynaptic Potentialsto Neural Networks

One neuron, signals from thousands of other neurons

Requires integration of signalsPSPs add up, balance outBalance between IPSPs and EPSPs

Neural networksPatterns of neural activityInterconnected neurons that fire together or

sequentially

Signals: From Postsynaptic Potentialsto Neural Networks

Synaptic connectionsElimination and creationSynaptic pruning

Figure 3.5 Synaptic pruning

Neurotransmitters Specific neurotransmitters work at specific

synapsesLock and key mechanism

Agonist – mimics neurotransmitter actionAntagonist – opposes action of a

neurotransmitter15 – 20 neurotransmitters known at presentInteractions between neurotransmitter

circuits

Table 3.1 Common Neurotransmitters and Some of their Functions

Organization of the Nervous SystemCentral nervous system (CNS)

Afferent = toward the CNSEfferent = away from the CNS

Peripheral nervous systemSomatic nervous systemAutonomic nervous system (ANS)

Sympathetic Parasympathetic

Figure 3.6 Organization of the human nervous system

Figure 3.7 The central and peripheral nervous systems

Figure 3.8 The autonomic nervous system (ANS)

Studying the Brain: Research MethodsElectroencephalography (EEG) Damage studies/lesioning Electrical stimulation (ESB)Transcranial magnetic stimulation (TMS)Brain imaging –

computerized tomography positron emission tomography magnetic resonance imaging

Brain Regions and FunctionsHindbrain – vital functions – medulla, pons,

and cerebellumMidbrain – sensory functions –

dopaminergic projections, reticular activating system

Forebrain – emotion, complex thought – thalamus, hypothalamus, limbic system, cerebrum, cerebral cortex

The Cerebrum:Two Hemispheres, Four Lobes

Cerebral Hemispheres – two specialized halves connected by the corpus collosumLeft hemisphere – verbal processing:

language, speech, reading, writingRight hemisphere – nonverbal processing:

spatial, musical, visual recognition

The Cerebrum:Two Hemispheres, Four Lobes

Four Lobes:Occipital – visionParietal - somatosensoryTemporal - auditoryFrontal – movement, executive control

systems

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Right Brain/Left Brain

Figure 3.16 Structures and areas in the human brain

Figure 3.18 The cerebral hemispheres and the corpus callosum

Figure 3.19 The cerebral cortex in humans

Figure 3.20 The primary motor cortex

Figure 3.21 Language processing in the brain

The Endocrine System:Glands and HormonesHormones – chemical messengers in the

bloodstreamPulsatile release by endocrine glandsNegative feedback system

Endocrine glandsPituitary – “master gland,” growth hormoneThyroid – metabolic rateAdrenal – salt and carbohydrate metabolismPancreas – sugar metabolismGonads – sex hormones

Genes and Behavior:The Field of Behavioral Genetics

Behavioral genetics = the study of the influence of genetic factors on behavioral traits

Chromosomes – strands of DNA carrying genetic informationHuman cells contain 46 chromosomes in

pairs (sex-cells – 23 single)Each chromosome – thousands of genes,

also in pairsDominant, recessiveHomozygous, heterozygousGenotype/Phenotype and Polygenic

Inheritance

Figure 3.25 Genetic material

Research Methods in Behavioral GeneticsFamily studies – does it run in the family?Twin studies – compare resemblance of

identical (monozygotic) and fraternal (dizygotic) twins on a trait

Adoption studies – examine resemblance between adopted children and their biological and adoptive parents

Figure 3.27 Genetic relatedness

Figure 3.28 Family studies of risk for schizophrenic disorders

Figure 3.30 Twin studies of intelligence and personality

Modern Approaches to theNature vs. Nurture DebateMolecular Genetics = the study of the

biochemical bases of genetic inheritanceGenetic mapping – locating specific genes -

The Human Genome ProjectBehavioral Genetics

The interactionist modelRichard Rose (1995) – “We inherit dispositions,

not destinies.”

Evolutionary Psychology:Behavior in Terms of Adaptive Significance

Based on Darwin’s ideas of natural selectionReproductive success key

Adaptations – behavioral as well as physicalFight-or-flight responseTaste preferencesParental investment and mating