Chapter 3
Biological Foundations of Behavior
© 2008 The McGraw-Hill Companies, Inc.
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The Nervous System
Brain: Structure and Function
Brain Damage and Plasticity
Genetics, Evolution, and Behavior
Application: Health and Wellness
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The Nervous System
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Neuroscience and Neuroscientists
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Characteristics of the nervous system:
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Complexity
Integration
Adaptability
Electrochemical transmission
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The Nervous System:
Pathways
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Afferent Nerves
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Efferent Nerves
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Carry information  spinal cord and brain
Carry information  muscles
Reflex Arc:
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Afferent nerve  Interneuron  Efferent nerve
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The Nervous System:
Divisions
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The Nervous System:
Divisions
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Central nervous system (CNS)
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Brain and spinal cord
Peripheral nervous system (PNS)
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Somatic nervous system
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Sensory nerves and muscular activity
Autonomic nervous system – internal organs
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Sympathetic nervous system – arouses
Parasympathetic nervous system – calms
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Neurons: Structure
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Brain: Approximately 100 billion neurons
Glial Cells: Provide support and nutrition
Specialized Cell Structure
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Cell body
Dendrites
Axon
Myelin sheath
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Neurons: Structure
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The Neural Impulse
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Resting Potential
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Action Potential
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Stable, negative charge of an inactive neuron
Ion gates cause depolarization
Brief, positive electrical charge: firing
All-or-None Principle
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Once initiated, it cannot be stopped
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Synapses and
Neurotransmitters
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Synaptic Transmission
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Neurochemical communication
Action potential (electrical impulse) is
converted into a chemical signal
Synapses
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Space between terminal buttons and the
receiving neuron’s cell body or dendrites
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Synapses and
Neurotransmitters
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Neurotransmitters
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Neurotransmitters either excite or inhibit
Acetylcholine
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Muscle actions, learning, memory
Alzheimer’s disease: ↓ Ach levels
Nicotine: ↑ Ach levels
GABA – inhibitory functions
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Anxiety: ↓ GABA levels
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Neurotransmitters
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Norepinephrine
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Stress and mania: ↑ Norepinephrine levels
Depression: ↓ Norepinephrine levels
Regulates sleep states in conjunction with ACh
Dopamine
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Stimulant drugs: ↑ Dopamine levels
Parkinson’s disease: ↓ Dopamine levels
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Neurotransmitters
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Serotonin
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Regulation of sleep, mood, attention, learning
Depression: ↓ Serotonin levels
Prozac  ↑ Serotonin levels
Endorphins
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Endogenous (natural) opiates
Mediate feelings of pleasure and pain
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Neurotransmitters
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Oxytocin
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Both a hormone and a neurotransmitter
Related to onset of lactation in new mothers
Related to attachment / emotional bonds
Drugs and Neurotransmitters
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Agonist – mimics or enhances NT effects
Antagonist – blocks effects of NT
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Studying the Brain
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Lesioning
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Naturally occurring or induced
Staining
Electrical Recording
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Electroencephalogram (EEG)
Single-unit recording
Brain damage, sleep, epilepsy, happiness
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Brain Imaging
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X-Ray
CT Scan
PET
MRI
fMRI
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Brain: Structure and Function
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Hindbrain, Midbrain, and Forebrain
Hindbrain
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Medulla – control breathing, regulate reflexes
Cerebellum – movement, coordination
Pons – sleep, arousal
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Brain: Structure and Function
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Midbrain
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Reticular Formation
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Stereotyped behavior patterns like walking
Brain Stem
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Alertness, breathing, heart rate, blood pressure
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Brain: Structure and Function
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Brain: Structure and Function
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Forebrain (continued next slide)
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Limbic System – memory and emotion
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Amygdala
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Hippocampus
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Emotional awareness and expression
Formation and storage of memories
Thalamus
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Relay station for much sensory information
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Brain: Structure and Function
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Forebrain (continued)
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Basal Ganglia
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Coordination of voluntary movements
Hypothalamus
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Eating, drinking, sexual behaviors
Emotion, stress, reward
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Cerebral Cortex
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Occipital Lobe – Vision
Temporal Lobe – Hearing, language
processing, memory
Frontal Lobe – Intelligence, personality,
voluntary muscles
Parietal Lobe - Spatial location, attention,
motor control
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Cerebral Cortex
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Somatosensory
and Motor Cortex
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Somatosensoy Cortex
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Motor Cortex
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Located in the parietal lobe
Processes info about body sensations
Located in the frontal lobe
Processes info about voluntary movements
Point-to-point Mapping
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Somatosensory
and Motor Cortex
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Split-Brain Research
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Corpus Callosum
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Large bundle of axons that connects the two
hemispheres of the brain
Hemispheric Specialization of Function
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Right hemisphere
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Spatial perception, visual recognition, emotion
Left hemisphere
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Verbal processing, speech, grammar
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Split-Brain Research
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Intersection: Happy Brains?
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Happiness: Prefrontal Lobe Asymmetry
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Positive emotional responses
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Negative emotional responses
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More left prefrontal lobe activity
More right prefrontal lobe activity
Caution: Correlational Research
Mindfulness (Awareness) Meditation
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The Endocrine System
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Set of glands that regulate the flow or
hormones into the bloodstream
Relatively slow communication system
Interconnected with the nervous system
Pituitary, thyroid, parathyroid, adrenal
glands, pancreas, ovaries, testes
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Brain Damage and Plasticity
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Recovery from brain damage depends on
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Age of the individual
Extent of the damage
Repairing the damaged brain
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Collateral sprouting
Substitution of function
Neurogenesis
Brain tissue implants
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Genetics and Behavior
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Chromosomes, DNA, and Genes
The Dominant-Recessive Genes Principle
The Human Genome Project
Behavior Genetics and Adoption Studies
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Fraternal and identical twins
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Genes and the Environment
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The “Nature versus Nurture” Debate
Nature describes one’s genetic potential
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Genotype – genetic heritage
Nurture  the expression of that potential
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Phenotype – observable characteristics
Both physical and psychological characteristics
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Application:
Health and Wellness
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Stressors – circumstances and events that
threaten individuals and/or tax their
coping abilities
Stress – our response to those stressors
Effects of acute and chronic stress
Cognitive restructuring and self-talk
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Chapter Summary
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Discuss the nature and basic function of the
nervous system.
Explain what neurons are and how they process
information.
Identify the brain’s levels and structures and
summarize the function of those structures.
© 2008 The McGraw-Hill Companies, Inc.
Chapter Summary
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Identify the endocrine system and describe how it
affects behavior.
Describe the brain’s capacity for recovery and
repair.
Explain how genetics increases understanding of
behavior.
Describe the role of the biological foundations of
human psychology in the body’s stress response.
© 2008 The McGraw-Hill Companies, Inc.
Chapter Summary
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The Nervous System
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Structure and function of the nervous systems
Structure of a neruon
Electrochemical communication
Neurotransmitters and their effects
Brain: Structure and Function
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Brain imaging techniques
Hindbrain, midbrain, forebrain
Cerebral lobes and functions
© 2008 The McGraw-Hill Companies, Inc.
Chapter Summary
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Brain Damage and Plasticity
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Genetics, Evolution, and Behavior
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Collateral sprouting, substitution of function,
neurogenesis, brain tissue implants
“Nature versus Nurture” and adoption studies
Application: Health and Wellness
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Stress and self-talk
© 2008 The McGraw-Hill Companies, Inc.