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Biological Bases of Behavior
AP Psych – Chapter 3
Biological Foundations of Behavior
Alice F. Short
Hilliard Davidson High School
Chapter Preview
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Nervous System
Neurons
Brain
Endocrine System
Damage, Plasticity, and Repair
Genetics and Behavior
Biological Foundations and Health and
Wellness
Nervous System
• neuroscience - study of the body’s
electrochemical communication circuitry
• characteristics of the nervous system
– complexity
• (metaphor = multitasking)
– integration
– adaptability (plasticity)
– electrochemical transmission
Nervous System: Pathways
• Afferent Nerves (in)
– carry information  spinal cord and brain
• Efferent Nerves (exit)
– carry information  muscles
The Two Main Divisions of the Nervous System:
• 1. Central Nervous System (CNS)
– brain and spinal cord
• 2. Peripheral Nervous System (PNS)
– somatic nervous system – sensory nerves
• muscular activity
– autonomic nervous system – internal organs
• sympathetic nervous system – arouses
• parasympathetic nervous system – calms
Nervous
System:
Divisions
1. Central Nervous System
• 1. Central Nervous System (CNS)
– brain and spinal cord
2. Peripheral Nervous System
• 2. Peripheral Nervous System (PNS) – composed of all
the sensory and motor nerves
– somatic nervous system (voluntary) – sensory nerves
• carries info to muscles  muscular activity
– allows you to move in cases of emergency
– allows you to move when you want to move
– “instruct” “tell” “decide” to move muscles
– autonomic nervous system (involuntary) – internal organs
• carries information to and from internal organs
• monitors breathing, heart rate, digestion
• sympathetic nervous system – arouses
– kicks into overdrive in cases of emergency (“fight or flight”)
– neurotransmitter: noradrenaline
• parasympathetic nervous system – calms
– medication techniques elicit response
– neurotransmitter: acetocholine
Nervous System: 2 Types of Cells
• neurons
– basic unit of the nervous system
– information processing
– part of neuron: dendrites, cell body (soma), axon,
myelin sheath, axon terminals, terminal buttons,
nucleus
– mirror neurons (in primates) – imitating behaviors of
someone else
• mimicking the movements of a coach or dancer, etc.
• glial cells
– provide support and nutrition
– carries nutrients from blood vessels  neurons
Neurons: Structure
• neuron – the type of cell that is the basic unit of
the nervous system – the nervous system
contains over 11 billion neurons
1. cell body (soma) – contains the nucleus
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directs the manufacture of substances that the neuron
needs for growth and maintenance
2. dendrites – branched appendages that carry
information to the cell body (receives info)
3. axon – conveys information away from the cell body
toward other cells
4. myelin sheath – layer of fat, covers the axon and aids
in neural transmission (faster and smoother
transmission)
Neurons: Structure
• dendrite  cell body  axon
Neurons: 3 Types
Neuron – the type of cell that is the basic unit of the nervous
system – the nervous system contains over 11 billion
neurons
1. sensory neurons are located in the body’s sense organs
(for example, the eye, ear, or nose) and send information
from these organs to the brain
2. motor neurons– convey information from the nervous
system to the body’s organs, glands, and muscles
3. interneurons (association neurons) transmit information
from one neuron to another within the nervous system
• Axons
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ions/ion channel
negatively/positively charged
semipermeable membrane
polarization
Neural
Impulse
• Resting Potential
– stable charge of an inactive neuron
– a negative charge on the inside of the cell membrane and a
positive charge on the outside
• Action Potential
– depolarization (ion channel opens)
• sodium ions flow into the membrane
– repolarization
– ion exchange sweeps along length of axon
• a brief wave of positive and electrical charge that sweeps down the axon
– all-or-none principle – intensity of the action potential is not
effected by depolarizing and greater levels
– once initiated, cannot be stopped
Transmission of Nerve Impulse
Synapses and Neurotransmitters
• Synapse / Synaptic Gap
– space between sending axon’s terminal buttons and
the receiving dendrite or cell body
– the neural message being delivered in a synaptic
transmission is carried across the synaptic gap by
chemical substances
• Synaptic Transmission
– electrical impulse is converted into a chemical signal
– axon vesicle releases neurotransmitter into gap
– dendrite receptor site detects neurotransmitter
Synapses and Neurotransmitters
© 2011 The McGraw-Hill Companies, Inc.
Neurotransmitters
• Neurotransmitters carry information across the synaptic
gap to next neuron. (chemical)
– Acetylcholine
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muscle actions, learning, memory
black widow venom ↑ Ach levels
botox (botulin) ↓ Ach levels
Alzheimer’s disease: ↓ Ach levels
– GABA
• anxiety: ↓ GABA levels
– Glutamate
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excitatory
learning & memory
involved in many psychological disorders
↑ causes migraines
– Norepinephrine
• stress and mania: ↑ norepinephrine levels
• depression: ↓ norepinephrine levels
• regulates sleep states in conjunction with ACh
Neurotransmitters (cont.)
• Dopamine
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voluntary movement
reward anticipation
stimulant drugs: activate dopamine receptors
Parkinson’s disease: ↓ dopamine levels
schizophrenia: ↑ dopamine levels
• Serotonin
– regulation of sleep, mood, attention, learning
– depression: ↓ serotonin levels
– prozac: ↑ serotonin levels
• Endorphins
– natural opiates
– mediate feelings of pleasure and pain
• Oxytocin
– both a hormone and a neurotransmitter
– related to onset of lactation in new mothers
– related to attachment/emotional bonds
Neurotransmitters
• Note: Drugs can interfere with
neurotransmitters
– mimics or enhances NT effects
– blocks effects of NT
Neural Networks
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interconnected pathways of nerve cells
integrate sensory input and motor output
take years to develop
a given piece of information embedded in
multiple connections between neurons
Studying the Brain
• Brain Lesioning
– naturally occurring or induced
• Electrical Recording
– electroencephalograph (EEG)
– single-unit recording
Brain Imaging
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X-Ray
CT Scan
PET
MRI
fMRI
TMS
Areas of the Brain
1. Hindbrain
2. Midbrain
3. forebrain
Reminder: any part of the brain is a part of the
central nervous system (CNS), which is a part
of the nervous system in general
Areas of the Brain: 1. Hindbrain
• Brainstem
– medulla – control breathing, regulate reflexes
– pons – sleep & arousal
• Cerebellum
– motor coordination
Areas of the Brain: 2. Midbrain
• Substantia Nigra
– Parkinson disease
• Reticular Formation
– stereotyped behavior patterns like walking
– manipulates neurotransmitters
Brain: Structure and Function
Areas of the Brain: 3. Forebrain
• Limbic System
– memory and emotion
– amygdala
• discrimination of objects needed for survival
• emotional awareness and expression
– hippocampus
• formation and recall of memories
• Thalamus
– relay station for much sensory information
• Basal Ganglia
– coordination of voluntary movements
• Hypothalamus
– eating, drinking, sexual behaviors
– regulate body’s internal state
– emotion, stress, reward
Cerebral Cortex
• Neocortex: outermost layer
• Four Lobes:
– occipital (vision)
– temporal (hearing, language processing, memory)
– frontal (intelligence, personality, voluntary
muscles)
– parietal (spatial location, attention, motor control)
Cerebral Cortex
Are Brains Wired to Recognize Faces?
• prosopagnosia
• fusiform face area (FFA)
– FFA – specifically for processing faces?
Somatosensory, Moor, and
Association Cortex
• Somatosensoy Cortex (in parietal lobe)
– body sensations
• Motor Cortex (in frontal lobe)
– voluntary movements
• Point-to-Point Mapping
• Association Cortex (75% of cortex)
– not sensory or motor, but associations between
Split-Brain
Research
• Corpus Callosum
– Large bundle of axons that connects the two
hemispheres of the brain
• W.J., the Split Brain Patient
• Hemispheric Specialization of Function
– left hemisphere
– verbal processing, speech, grammar
• Broca’s Area
• Wernicke’s Area
– right hemisphere
• spatial perception, visual recognition, emotion
Hemispheres of
the Cortex
Happy Brains
• Happiness: Prefrontal Lobe Asymmetry
– positive emotional responses
• more left prefrontal lobe activity
– negative emotional responses
• more right prefrontal lobe activity
• Biofeedback
• Mindfulness (Awareness) Meditation
Endocrine System
• set of glands that regulate the body by
secreting hormones into the bloodstream
• hormones = chemical messages
• relatively slow communication system
• interconnected with the nervous system
• pituitary, thyroid, parathyroid, adrenal glands,
pancreas, ovaries, testes
Brain Damage and Plasticity
• Recovery from brain damage depends on
– age of the individual
– extent of the damage
• Repairing the damaged brain
– collateral sprouting
– substitution of function
– neurogenesis
– brain tissue grafts
Genetics and Behavior
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chromosomes, genes, and DNA
Human Genome Project
dominant-recessive genes principle
molecular genetics
selective breeding
behavior genetics and adoption studies
Genes and the Environment
• Genotype – genetic heritage + the effects of
experience =
• Phenotype – observable characteristics
– environment alters how genetic traits develop
– both physical & psychological characteristics
– genetic expression
Biological Foundations
and Health and Wellness
• stressors
– …circumstances and events that threaten
individuals and/or tax their coping abilities
• stress
– …our response to those stressors
• causes/effects of acute and chronic stress
Chapter Summary
• 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.
• Identify the endocrine system and describe
how it affects behavior.
Chapter Summary
• 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.
Chapter Summary
• 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
– brain imaging techniques
– hindbrain, midbrain, forebrain
– cerebral lobes and functions
Chapter Summary
• Brain Damage and Plasticity
– collateral sprouting, substitution of function,
neurogenesis, brain tissue grafts
• Genetics and Behavior
– “genes v. environment” and adoption studies
• Biological Foundations & Health and Wellness
– acute and chronic stress