Chapter 3
Biopsychology and the
Foundations of Neuroscience
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ISBN: 0-131-73180-7
Copyright © Allyn & Bacon 2007
Some Brain Facts…
It is about the size of grapefruit
3 pounds, pinkish-gray, wrinkled surface
100 billion nerve cells, sometimes with up to
10,000 connections to other cells
At birth the brain has extra nerve cells that die
off; by adolescence that stabilizes and the total
number is constant later on
There is some loss and gain through adulthood,
but by age 70 we end up with over 98%
Copyright © Allyn & Bacon 2007
What is Biopsychology?
Biopsychology –
The specialty in psychology that studies
the interaction of biology, behavior, and
the environment
Neuroscience –
Interdisciplinary field that focuses on the
brain and its role in psychological
processes
Copyright © Allyn & Bacon 2007
How Are Genes and
Behavior Linked?
Evolution has fundamentally
shaped psychological
processes because it favors
genetic variations that
produce adaptive behavior
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How Are Genes and
Behavior Linked?
Innate –
Inborn; present at birth; part of the
organism’s biological heritage
Evolution –
The gradual process of biological change
that occurs in a species as it adapts to its
environment
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Evolution and Natural Selection
Natural selection –
The driving force behind evolution, by
which the environment “selects” the fittest
organisms
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How Natural Selection Works
Environmental pressure
(changes in the environment)
Competition
(for resources)
Selection of fittest phenotype
(from among a variety of phenotypes)
Reproductive success
(genotype corresponding to fittest
phenotypes passed to next generation)
Frequency of that genotype increases
(in next generation)
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Genes and Inheritance
Genotype –
An organism’s genetic makeup
Phenotype –
An organism’s observable physical
characteristics
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Genes and Inheritance
Mutations –
Genetic variations, which occur
randomly, especially during the
recombination of chromosomes in sexual
reproduction
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Chromosomes, Genes, and DNA
DNA (deoxyribonucleic acid)–
A long, complex molecule that encodes
genetic characteristics
Genes (they are like words in a sentence)–
The functional units of a chromosome
Composed of nucleotides—they are like the
letters in words (A,G,T,C)
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Chromosomes, Genes, and DNA
Chromosomes (like a string of words; they
include punctuation and timing)–
Tightly coiled threadlike structures along
which the genes are organized
Sex chromosomes –
The X and Y chromosomes that
determine our physical sex characteristics
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Genetic Explanations for
Psychological Processes
Genes influence our psychological characteristics
as well as our physical traits—the complete
package of human genes=30,000
There are 46 chromosomes; 23 pairs
Multiple genes contribute to schizophrenia,
Alzheimer’s disease; an extra chromosome 21
results in Down syndrome
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How Does the Body
Communicate Internally?
The body’s two
communication systems, the
nervous system and the
endocrine system, both use
chemical messengers to
communicate with targets
throughout the body
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The Neuron
Types of Neurons
Sensory neurons—afferent--(carry
messages from sense receptors
towards the CNS)
Motor neurons—efferent--(carry
messages from CNS toward muscles
and glands)
Interneurons (carry messages
between nerve cells)
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The Structure of a Neuron
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The Neural Impulse
Neural impulse –
Brief electric surge that carries the
neuron’s message
Ions –
Charged particles that are moved across
the cell membrane
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The Neural Impulse
Resting potential—negative—when the cell is
inactive and ready to fire
Action potential—impulse caused in a fraction of
second when the charge changes from
negative to positive…this is done in an all or
none manner
Synapse—gap between neurons or neurons and
muscles/glands
Synaptic transmission—relaying information
across the synapse by use of chemical
neurotransmitters
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Neurotransmitters
Neurotransmitters –
Chemical messengers that relay neural
messages across the synapse
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Seven Important Neurotransmitters
Dopamine
Serotonin
Norepinephrine
Acetylcholine
GABA
Glutamine
Endorphins
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Neurotransmitters
Dopamine
Serotonin
Norepinephrine
Normal Function:
Produces sensations of
pleasure and reward; used
by CNS neurons in
voluntary movement
Problems with Imbalance:
Acetylcholine
GABA
Glutamine
Endorphins
Schizophrenia, Parkinson’s
disease
Substances that Affect:
Cocaine, amphetamines,
Ritalin, alcohol
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Neurotransmitters
Dopamine
Serotonin
Normal Function:
Regulates sleep and
dreaming, mood, pain,
aggression, appetite and
sexual behavior
Norepinephrine
Problems with Imbalance:
Acetylcholine
GABA
Depression, certain anxiety
disorders, obsessivecompulsive disorder
Glutamine
Substances that Affect:
Endorphins
Prozac, hallucinogenics
(e.g. LSD)
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Neurotransmitters
Dopamine
Serotonin
Norepinephrine
Normal Function:
Controls heart rate, sleep,
sexual responsiveness,
stress, vigilance and
appetite
Problems with Imbalance:
Acetylcholine
GABA
Glutamine
Endorphins
High blood pressure,
depression
Substances that Affect:
Tricyclic antidepressants,
beta blockers
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Neurotransmitters
Dopamine
Serotonin
Norepinephrine
Acetylcholine
Normal Function:
Primary transmitter used by
neurons carrying messages
from CNS; involved in
some kinds of learning and
memory
Problems with Imbalance:
GABA
Certain muscular disorders,
Alzheimer’s disease
Glutamine
Substances that Affect:
Endorphins
Nicotine, botulism toxin,
curare, atropine
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Neurotransmitters
Dopamine
Serotonin
Norepinephrine
Normal Function:
Most prevalent inhibitory
neurotransmitter in neurons
of CNS
Problems with Imbalance:
Acetylcholine
Anxiety, epilepsy
GABA
Substances that Affect:
Glutamine
Endorphins
Barbiturates, tranquilizers
(e.g. Valium, Librium),
alcohol
Copyright © Allyn & Bacon 2007
Neurotransmitters
Dopamine
Normal Function:
Norepinephrine
Primary excitatory
neurotransmitter in CNS;
involved in learning and
memory
Acetylcholine
Problems with Imbalance:
Serotonin
GABA
Glutamine
Brain damage after stroke
Substances that Affect:
PCP (“angel dust”)
Endorphins
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Neurotransmitters
Dopamine
Normal Function:
Serotonin
Pleasurable sensations and
control of pain
Norepinephrine
Problems with Imbalance:
Acetylcholine
Lowered levels resulting
from opiate addiction
GABA
Glutamine
Endorphins
Substances that Affect:
Opiates: opium, heroin,
morphine, methadone
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Plasticity
Plasticity –
Ability of the nervous system to adapt or
change as the result of experience;
sometimes helps the nervous system
adapt to physical damage
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Glial Cells
Glial cells (from the Greek for “glue”)
•
•
•
•
Provide structural support for neurons
Help in forming new synapses
Form myelin sheath
MS (multiple sclerosis) attacks the myelin
sheath resulting in poor conduction and loss
of movement control
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The Organization of the
Nervous System
Nervous system
Peripheral nervous
system
Autonomic
nervous system
Sympathetic
nervous system
Central nervous
system (CNS)
Somatic
nervous system—
splits into sensory
and motor NS
Parasympathetic
nervous system
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The Endocrine System
(the body’s chemical messenger system)
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The Endocrine System
Pituitary gland –
Master gland that produces
hormones influencing the
secretions of all other endocrine
glands; produces hormone that
influences growth; attached to
hypothalamus
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How Does the Brain
Produce Behavior and
Mental Processes?
The brain is composed of
many specialized modules
that work together to create
mind and behavior
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Windows on the Brain
EEG (electroencephalograph) –
Device for recording brain waves,
typically by electrodes placed on the
scalp
Brain waves –
Patterns of electrical activity generated
by the brain
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Windows on the Brain
Epilepsy –
Brain disorder that is often marked by
seizures and loss of consciousness;
caused by out-of-control electrical activity
in the brain
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Windows on the Brain
Lesions –
Tissue damage that results from
disease or injury
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Windows on the Brain
Brain scans –
Recordings of the brain’s electrical or
biochemical activity at specific sites
• CT scanning (computerized tomography) X rays are
passed through at various angles creating a static
image of brain structure
• PET scanning (positron emission tomography)
senses low-level radioactive glucose to create
brightly colored areas of activity
• MRI (magnetic resonance imaging) also functional
or fMRI creates highly detailed pictures from pulses
of magnetic energy
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Three Layers of the Brain
Brain stem and cerebellum
Drive vital functions, such as heart rate,
breathing, digestion
Limbic system
Adds emotions, complex motives, increased
memory abilities
Cerebrum
Enables reasoning, planning, creating,
problem solving
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The Brain Stem and Cerebellum
Thalamus
Pons
Cerebellum
Medulla
Brain stem
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The Limbic System
Hypothalamus –
Serves as the
brain’s bloodtesting
laboratory,
constantly
monitors blood to
determine the
condition of the
body
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The Limbic System
Amygdala –
Involved in
memory and
emotion,
particularly fear
and aggression
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The Limbic System
Hippocampus –
Involved in establishing
long-term memories
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The Cerebrum
Cerebrum –
Topmost layer of the brain; the
bulbous cap over the limbic system
Cerebral cortex –
Thin gray-matter covering of the
cerebrum; carries on thinking and
perceiving=2/3 of brain’s total mass
Cerebral hemispheres –
The two walnut shaped halves of the
cerebrum, connected by the corpus
callosum
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The Four Lobes of the
Cerebral Cortex
Frontal lobes
(movement…motor cortex,
planning, deciding, perceiving)
Parietal lobes
(touch
sensation…somatosensory
cortex and spatial
relationships) Occipital lobes
(contain visual cortex)
Temporal lobes
(process sounds/speech and
has some ties to memory)
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The Cooperative Brain
Association cortex –
Cortical regions that combine information
from various other parts of the brain
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Cerebral Dominance
Cerebral dominance –
Tendency of each brain hemisphere to exert
control over different functions
Aphasia –
The loss of speech caused by brain damage
Speech production lies in the frontal lobe, left
hemisphere (Broca’s area. Understanding
language lies in the left parietal and temporal
lobes (Wernicke’s area).
Spatial orientation –
Process of locating one’s body or other objects
in space
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Specialization of the
Cerebral Hemispheres
Left Hemisphere
Right Hemisphere
• Spontaneous
speaking and
writing
• Responses to
complex commands
• Word recognition
• Memory for words
and numbers
• Sequences of
movements
• Positive emotion
• Repetitive but not
spontaneous
speaking
• Responses to simple
commands
• Facial recognition
• Memory for shapes
and music
• Spatial interpretation
• Emotional
responsiveness
• Negative emotion
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The Split Brain
Split-brain patients –
Individuals who have had the corpus
callosum surgically severed
Duality of consciousness –
Condition in which a split-brain patient
has a separate consciousness in each
hemisphere
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End of Chapter 3
Copyright © Allyn & Bacon 2007