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Ch. 2
The Biological Basis of Behavior
1. Neurons: The Messengers
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A. Dendrites
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B. Cell Body
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Carries information to the cell body
Also called soma
C. Axon
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Carries information to the next cell
A typical myelinated neuron
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D. Myelin Sheath
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Covers axon
Insulates
Speeds up impulse
E. Sensory
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Afferent
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F. Motor
 Efferent
G. Interneurons
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Association
H. Support Cells - Glial Cells
 Cells that insulate and support neurons
2. The Neural Impulse or Action
Potential
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A. Ions
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B. Resting Potential
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Charged molecules
Potential Energy
C. Polarization/ Depolarization
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Away/toward zero (neutral)
The neural impulse --communication
within the neuron
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D. Action Potential
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E. Graded Potentials
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Sudden change in charge
Subthreshold stimulation
Summation
F. Threshold of Excitation
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Results in Action Potential
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G. All-or-None Law
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H. Absolute Refractory Period
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Cells either fire or not (no halfway)
I.
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Another Action Potential cannot occur
Relative Refractory Period
Neuron would only respond to very strong impulse
The neural impulse -communication within the neuron
3. The Synapse
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A. Synaptic Space or synaptic cleft
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B. Terminal button
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Tiny gap between neurons
Enlarge area at end of axon
C. Synapse
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Terminal button of one neuron, the space and the
next neuron
Synaptic transmission –
communication between neurons
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D. Synaptic Vesicles
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E. Neurotransmitters
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Sacs in terminal button that release chemicals into
synapse
Chemicals released by synaptic vesicles
F. Receptor Sites
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Location on receptor neuron for specific
neurotransmitter
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4. Neurotransmitters
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Acetylcholine
 Important role in arousal and attention
Dopamine
 Affects neurons associate with voluntary
movement
Serotonin
 Sets an emotional tone
Endorphins
 Reduce pain by turning down neurons
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5. Psychopharmacology
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Cocaine
 Prevents reabsorption of dopamine, leading to
heightened arousal
Antidepressant and antipsychotic medications use the
same processes
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6. Neural Plasticity
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Brain shaped by environment
Possible child abuse marker
7. Neurogenesis
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Production of new brain cells
Brain growth and experience
8. The Central Nervous System
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A. The Organization of the Nervous System
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Central and Peripheral Nervous Systems
B. The Brain
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The central core
 Hindbrain
 Medulla - controls breathing, heart rate, and
blood pressure
 Pons - controls sleep-wake cycle
 Cerebellum - coordination of movement
A schematic diagram of the divisions of the
nervous system and their various subparts
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Midbrain
 Thalamus - Relay from sense receptors
 Hypothalamus
 Emotions and motivation
 Feeding, fleeing, fighting, and sex
 Reticular formation
 Network of neurons
 Alert and arouse higher brain
 Limbic system
 Ring of structures important to learning and
emotional behavior
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Four lobes of the cerebral cortex
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Frontal lobe
 Voluntary movement, attention, goal behavior,
appropriate emotions
Parietal lobe
 Sensory information from body
Occipital lobe
 Interprets visual information
Temporal lobe
 Hearing, balance, some emotions and motivations
Parts of the brain
9. Hemispheric Specialization
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A. Corpus Callosum
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B. Language
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Fibers that connect hemispheres
Usually located in the left hemisphere
C. Cognitive and Emotional Style
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Left hemisphere may operate more analytically
Right hemisphere may excel in spatial tasks and
expression of emotions
The cerebral hemispheres
10. New tools for Studying the Nervous
System
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A. Microelectrode Techniques
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B. Macroelectrode Techniques
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Very small pipette to stim. Individual cells
EEG
C. Structural Imaging
Computerized Axial Tomography (CT-scan)
 X-ray 3-D image
 Magnetic Resonance Imaging (MRI)
 Magnetic field/radio waves
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D. Functional Imaging
EEG-electrical activity on the scalp from millions of
neurons
 Magentoencephalography (MEG)
 More precise than EEG
 Magnetic source imaging (MSI)
 Similar to EEG
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Positron Emission Tomography (PET) - radioactive
glucose
 Single Photon Emission Computed Tomography
(SPECT)
 Functional magnetic resonance imaging (fMRI)
 Show function and structure
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11. Spinal cord
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Complex cable of nerves that
connects brain to rest of the body
Carry motor impulses to internal
organs and muscles
Carry information from
extremities and internal organs to
the brain
Permit some reflex movements
12. The Peripheral Nervous
System
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A. Afferent neurons
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Neurons that carry messages from sense organs to
spinal cord
B. Efferent Neurons
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Neurons that carry messages from the spinal cord or
brain to muscles and glands
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C. Somatic Nervous System
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Body systems
D. Autonomic Nervous System
Parasympathetic Nervous System
 Relaxation, repair, sleep, digestion, sexual
arousal
 Sympathetic Nervous System
 Emergency response
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The sympathetic and parasympathetic
divisions of the autonomic nervous system
13. The Endocrine System
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A. The Thyroid Gland
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B. The Parathyroid Glands
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Controls calcium and phosphate
C. The Pineal Gland
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Controls metabolism
Regulates activity levels
D. The Pancreas
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Regulates blood-sugar levels
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E. The Pituitary Gland
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F. Gonads
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Regulates many behaviors and other glands
Ovaries and testes
G. Adrenal Glands
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Reaction to stress
The glands of the endocrine
system
14. Genes, Evolution, and Behavior
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A. Genetics
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Heredity - transmission of trait from one generation to
next
Chromosomes
 Pairs of thread like bodies that contain genes
Deoxyribonucleic acid (DNA)
 Molecular in double-helix
 Code of life
Traits
 Characteristics on which we differ
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B. Behavior Genetics
Family studies
 Twin studies
 Identical twins
 Fraternal twins
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Dominant and Recessive Traits
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C. Evolution
D. Evolutionary Psychology
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Natural selection
E. Social Implications