Introduction to Psychology
Biopsychology
Learning Objective 3
Demonstrate a fundamental understanding
of the biological basis of behavior
Part I:
The Nervous Systems
• The central nervous
system (CNS)
consists of the brain
and spinal cord
• The peripheral
nervous
system (PNS) is
comprised of the
somatic and
autonomic nervous
systems
Pathways
• Nerves carry
information
afferent 🡨
efferent 🡨
Central Nervous System = Brain and Spinal Chord
The Brain: Plasticity
The brain’s ability to change, adapt, and
reorganize itself is called brain plasticity.
The Brain: Lateralization
• Each hemisphere
controls the opposite
side of the body
• There is some
specialization of
function, especially
language
The Brain: Corpus Callosum
• The two hemispheres
are connected by a
thick band of neural
fibers known as
the corpus callosum,
that allows the two
hemispheres to
communicate with
each other
Forebrain, Midbrain, and Hindbrain
Forebrain: The Lobes of the Brain
The forebrain is divided into four lobes.
Exploring a 3D Brain: The Forebrain
• https://www.brainfacts.org/3d-brain - intro=true
Frontal Lobe
• Prefrontal
Cortex
• Motor Cortex
• Broca’s Area
Parietal Lobe
• Somatosensory
Cortex
Temporal Lobe
• Wernicke’s
Area
Occipital Lobe
• Visual Cortex
Exploring a 3D Brain: The Limbic System
• https://www.brainfacts.org/3d-brain - intro=true
• Amygdala
• Hypothalamus
• Hippocampus
Exploring a 3D Brain: The Midbrain
• https://www.brainfacts.org/3d-brain - intro=true
• Substantia Nigra
• Reticular Formation
Exploring a 3D Brain: The Hindbrain
• https://www.brainfacts.org/3d-brain - intro=true
• Medulla
• Pons
• Cerebellum
How does the Brain
communicate?
• Glial cells provide
physical and
metabolic support
to neurons,
• Neurons (left) act
as interconnected
information
processors
• 80-100 Billion
Neuron Structure
Neuron Structure: Synapses
and Receptors
How Neurons Communicate: Resting Potential
At resting potential, Na+ is more highly concentrated outside the cell
in the extracellular fluid, whereas K+ is more highly concentrated
near the membrane in the cytoplasm or intracellular fluid. Other
molecules, such as chloride ions and negatively charged proteins
(brown squares), contribute to a positive net charge in the
extracellular fluid and a negative net charge in the intracellular fluid.
How Neurons Communicate: Action Potential
During the action
potential, the
electrical charge
across the
membrane
changes
dramatically
How Neurons Communicate: Reuptake
Reuptake involves
moving a
neurotransmitter
from the synapse
back into the axon
terminal from
which it was
released
NEUROTRANSMITTERS
3
Dopamine
• voluntary movement
• reward anticipation
• stimulant drugs: activate
dopamine receptors
• Parkinson’s disease: ↓
dopamine levels
• schizophrenia: ↑ dopamine
levels
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Steven Puetzer/Getty Images
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© Lars A. Niki
© McGraw-Hill Education
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NEUROTRANSMITTERS
4
Serotonin
• regulation of sleep, mood,
attention, learning
• depression: ↓ serotonin levels
• Prozac: ↑ serotonin levels
Endorphins
• natural opiates
• mediate feelings of
pleasure and pain
Photo credits: © Elena
Elisseeva/Alamy
© McGraw-Hill Education
Permission required for reproduction or display
NEUROTRANSMITTERS
5
Oxytocin
• both a hormone and a
neurotransmitter
• related to onset of lactation
in new mothers
• related to
attachment/emotional
bonds
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Images/Jupiterimages
© Stockbyte / PunchStock
© McGraw-Hill Education
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Psychoactive Drugs
• Psychoactive drugs
correct
neurotransmitter
imbalances
• Agonists mimic a
neurotransmitter at
the receptor site and,
thus, strengthen its
effects
• Antagonists block the
normal activity of a
neurotransmitter at
the receptor
Application:
Adenosine is a neurotransmitter (electrochemical in the
brain) that causes drowsiness.
To the neurons responsible for sending and receiving
Adenosine, Caffeine looks very similar to Adenosine
when attaching to their receptor sites. In the end,
caffeine blocks the effects of Adenosine.
What type of chemical is Caffeine?
Answer: Antagonist
The Peripheral Nervous System
PNS: the
Autonomic
Nervous
System
The Endocrine System
• Consists of a series of
glands that produce
chemical substances
known as hormones
• Hormones regulate
behaviors such as
aggression, mating, and
parenting of individuals
• The study of psychology
and the endocrine
system is called
behavioral
endocrinology
The Parts of the Endocrine System
Application:
• Imagine you are on
an airplane preparing
to jump out for your
first-ever experience
skydiving.
Which nervous systems
would be involved, and
in what way?
GENETICS AND BEHAVIOR
Chromosomes, Genes, and DNA
Human Genome Project
Dominant-Recessive Genes
Principle
Molecular Genetics
Selective Breeding
Genome-Wide Association
Behavior Genetics and Adoption
Studies
© McGraw-Hill Education
Permission required for reproduction or display
Gene --> <--Environment
Interactions
•
The range of reaction:
genes set definite limits
on potential, and
environment
determines how much
of that potential is
achieved
•
Genetic environmental
correlation
•
Epigenetics studies how
the same gene can
lead to different results
Quick Review
• How many parts of the brain can you list?
• What are the basic structures of a neuron and the
function of each structure?
• How do messages travel through the neuron?
• What is the role of the endocrine system?
• How do nature, nurture, and epigenetics
influence personality and behavior?
Learning Objective
Demonstrate a fundamental understanding
of the biological basis of behavior
Part II: Sensation Vs. Perception
• Sensation
the process of receiving stimulus energies from the
external environment and transforming them into
neural energy.
• Perception
the process of organizing and interpreting sensory
information
Sensation vs. Perception
Bottom-Up Processing
• outside world’s influence on perception
Top-Down
Processing
• internal/mental world’s influence on
perception
• expectations & prior understanding
SENSORY
THRESHOLDS
1
Absolute
Threshold
the minimum amount of energy an organism
can detect
Photo credit: © Stockdisc RF
PERCEPTION
Attention
• focusing awareness on a narrowed aspect of the
environment
Selective Attention
• cocktail party effect (automatic
selection)
PERCEPTION
Sensory Adaptation
FROM SENSATION TO PERCEPTION
Transduction