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PSYCHOLOGY:
Perspectives & Connections
2nd Edition
GREGORY J. FEIST
ERIKA L. ROSENBERG
Copyright 2012 The McGraw-Hill Companies,
Inc.
The Biology of Behavior
Chapter Three
Copyright 2012 The McGraw-Hill Companies,
Inc.
Chapter Preview

Genes and Behavior
The Nervous System
The Brain
Measuring the Brain
The Endocrine System

Bringing It All Together: Making




Connections in the Biology of Behavior
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1
Genes and Behavior
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Chromosomes







DNA
Genes
Genome
Alleles
Dominant genes
Recessive genes
Behavioral genetics
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Principles of Behavioral
Genetics
1.
2.
3.
4.
The relationship between genes and
behavior is complex
Most behaviors derive from many genes
Studying twins and adoptees helps
separate heredity and the environment
The environment affects how and when
genes affect behavior
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2
Complex Connections
between Genes and Behavior


Specific genes can cause specific
diseases but play only a small part in
creating
g a given
g
behavior
Environmental events can interact with
genes to make behaviors more or less
likely
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Polygenic Influence on
Behavior

Traits tend to be influenced by many genes
– Monogenic transmission

The hereditary passing on of traits determined by
a single gene
– Polygenic transmission


When many genes interact to create a single
characteristic
Much more common than monogenetic
transmission
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Genes and the
Environment


Teasing apart and identifying genetic
and environmental influences on
behavior requires
q
special
p
techniques
q
Heritability refers to the extent to
which a characteristic is influenced by
genetics
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3
Genes and the
Environment
• Twin-adoption studies
-
•
the study of hereditary influences on twins, both
identical and fraternal, who were raised together and
apart.
G
Gene-by-environment
b
i
t iinteraction
t
ti
research
– Studies hereditary influences by comparing genetic
markers (specific parts of the human genome)
– Involves observing the interaction of genetic
differences and the environment to assess the
impact on how certain behaviors are produced in
some people but not others
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Epigenetics: How the
Environment Changes
Gene Expression


Environmental events influence how and
when genes are activated or deactivated
Does not change
g the structure,, but rather
the activity of DNA
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The Nervous System
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4
Organization of the Nervous
System
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Organization of the Nervous
System

Central nervous system

Peripheral
p
nervous system
y
– Brain and spinal cord
– Somatic (voluntary) nervous system
– Autonomic (involuntary) nervous system

Sympathetic nervous system

Parasympathetic nervous system
– Fight or flight response
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The Sympathetic and
Parasympathetic Nervous
Systems
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5
The Cells of the Nervous
System:
Glial Cells and Neurons

Glial Cells
– The “glue” that holds the nervous system
together

Ne
Neurons
ons
– Cells that process and transmit information in
the nervous system



Building blocks of the nervous system
Information travels within a neuron in the form of an
electrical signal by action potentials
Information travels between neurons via chemicals
called neurotransmitters
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The Structure of Neurons

Soma
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Axon
– Nucleus
– Myelin sheath


Dendrites
Synapse
– Terminal button
– Synaptic cleft
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The Types of Neurons

Sensory neurons

Motor neurons
– Receive incoming sensory information
– Carry commands for movement
– Includes mirror neurons

Interneurons
– Communicate only with other neurons
– By far the most common type of neuron
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Neural Communication: The
Action Potential

Action potential
– Ions



Resting potential
Refractory period
The all-or-none
principle
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Communication Between
Neurons: Neurotransmission

Synaptic vesicles
– Tiny sacs in the
terminal buttons
that contain
neurotransmitters
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Communication Between
Neurons: Neurotransmission

Two ways to remove excess
neurotransmitters from the synaptic
cleft
– Enzymatic degradation
– Reuptake


Presynaptic neuron
Postsynaptic neuron
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Common
Neurotransmitters
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The Brain
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Evolution of the Human
Brain
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Overview of Brain
Regions

Hindbrain
– Medulla
– Pons
– Cerebellum
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Overview of Brain
Regions

Midbrain
– Reticular formation
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Overview of Brain
Regions

Forebrain
– Thalamus


Sensory relay station
S ll is
Smell
i the
th only
l
sensory system that
has no thalamic
relay
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9
Overview of Brain
Regions

Forebrain
– Limbic system


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Hypothalamus
Hi
Hippocampus
Amygdala
Cingulate gyrus
Basal ganglia
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Cerebrum and Cerebral
Cortex

Cerebrum
– Two hemispheres
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Frontal lobes
T
Temporal
l lobes
l b
Parietal lobes
Occipital lobes
Cerebral cortex
– Outer layer
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Cerebral Hemispheres

The two halves of the cerebrum have
different processing “styles”
– Left hemisphere – analytical and focused
– Right hemisphere – insight and solutions to
ideas

Corpus Callosum
– A thick bundle of nerve fibers that connect the
two cerebral hemispheres
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Cerebral Hemispheres

Language
– Left hemisphere
– Aphasia

Broca’s area

Wernicke’s area
– Speech production
– Speech comprehension
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Communication Between
the Hemispheres

Two hemispheres do
not operate
independently
– Activity across the
corpus callosum allows
the hemispheres to
work interdependently
– Split-brain research
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Brain Plasticity and
Neurogenesis


Neuroplasticity
Neurogenesis
– Arborization
– Synaptogenesis
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Breaking New Ground:
Neurogenesis
g
in the
Adult Brain
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Evidence of Neuron
Growth

1960s
– cell division in the brains of adult rats was
detected
– Joseph Altman

1980s and 1990s
– Neurogenesis in hippocampus
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Environmental Effects on
Neuron Growth

Elizabeth Gould
– Complex environmental settings showed
g
in animals
brain growth

Fred “Rusty” Gage (Phineas’s cousin!)
– BrdU
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Measuring the Brain
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Electroencephalography

EEG
– Records electrical
activity
– Shows
Sh
when
h brain
b i
activity occurs but
not where
– Event-related
potential (ERP)

Helps measure
cognitive processes
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Magnetic Resonance
Imaging and Functional MRI

MRI
– Uses magnetic fields to produce very finely
detailed images of the structure of the human
b
brain
i and
d other
th soft
ft ti
tissues
– Shows where but not when

fMRI
– Variation on MRI, tells about brain activity
– Tracks blood oxygen use in brain tissue
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Magnetic Resonance
Image
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Positron Emission
Tomography

PET
– Measures blood flow to brain areas in the
active brain
– Radioactive form of oxygen (glucose) is
injected into participant and can be
tracked
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The Endocrine System
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14
The Endocrine System

System of glands
that secrete and
regulate hormones
–
–
–
–
–
–
Hormones
Hypothalamus
Pituitary gland
Thyroid gland
Pancreas
Adrenal glands
 Catecholamines
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Bringing It All Together
Making Connections in
the Biology
gy of Behavior:
What Esref Armagan’s
Story Reveals About the
Brain
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What Esref Armagan’s Story
Reveals About the Brain

The visual images that Armagan forms from his
sense of touch activate the same region of the
brain that is active when seeing people see
something - the occipital lobe
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