BIOPSYCHOLOGY
Everything that is psychological is
simultaneously biological.
Nervous system, endocrine system,
genetics and prenatal environment
DIVISIONS OF THE NERVOUS SYSTEM
• Central nervous system
• Peripheral nervous system
DIVISIONS OF THE NERVOUS SYSTEM
• Somatic nervous system
• Autonomic nervous system
DIVISIONS OF THE NERVOUS SYSTEM
• Sympathetic nervous
system
• Parasympathetic nervous
system
• Think: “para-”
chute as it slows
you down.
Nervous System
• Steps of the neural chain
Neurons: the cells that make up the nerves
Part
Definition
Function
A. dendrites
Bushy fibers of one end of the
neuron that receive information
Are stimulated into activity by
neurotransmitters
B. axon
Pass the information through the
cell from the dendrites
C. myelin
sheath
Layer of fatty tissue that insulates
the axon of some neurons
The path of the electrical
impulse (action potential) thru
neuron
Speeds the electrical impulse
down the axon; degenerated
by multiple sclerosis
D. axon
terminal
The end of the neuron
E. synapse
F. vesicles
Upon stimulation it released
neurotransmitters into the
synapse or takes them back up
(reuptake)
The tiny gap between dendrites and The space btw where the
axon terminals
neurotransmitters move from
axon terminal to dendrites
Tiny, near spherical packets within Stores the NT until the action
the axon terminal that contain high potential triggers its release
concentrations of neurotransmitters into the synapse
Types of Neurons
• Sensory (afferent) vs.
Motor (efferent) neurons:
• Sensory/afferent neurons
take messages away from
sensory organs to the
brain.
• Motor/efferent neurons
take messages from the
brain to the muscles
resulting in motor tasks.
• Interneurons: central
nervous system neurons
that internally
communicate and
intervene between the
sensory inputs and
motor outputs. We
have billions and
billions of these.
Neural communication in the cell
• Neurons are either excited or inhibited and it
is “all or nothing”…most votes wins!
Neural communication in the cell
• When “excited” an
electrical impulse called
an action potential
travels down the axon
and it is propagated by
the opening and closing
of sodium and
potassium “gates.”
Neural communication between cells
• A synapse (gap) exists
between an axon and a
neighboring dendrite.
When stimulated the
axon terminal will
release
neurotransmitters into
the synapse wear they
will travel to excite the
next neuron.
Neurotransmitters
Neurotransmitter
Effect
Norepinephrine
Epinephrine
Helps control alertness and arousal; compliments adrenalin
NT that functions to speed up body processes, is highly arousing,
chemically identical to adrenalin but is released by neurons.
Endorphins
“endogenous morphine” natural opiates that are released in
response to pain and vigorous exercise; an inhibitory NT resulting in
pain reduction and pleasurable feelings
Plays a role in learning and memory. Messenger between a motor
neuron and a skeletal muscle. Allows for the contraction of muscles.
90% depletion of ACH in ppl with Alzheimer’s disease.
An inhibitory NT. It is strongly associated with our reward system. If
it feels good, it probably involves dopamine. Excessive activity at
dopamine receptors has been linked to schizophrenia; reduced is
associated with Parkinson’s disease.
Affects mood, hunger, sleep, and arousal. Prozac and similar anti
depressants raise serotonin activity and reduces feelings of anxiety.
NT that functions almost always as an neural inhibitor; it helps you
Acetycholine (ach)
Dopamine
Serotonin
GABA
Chemically Manipulating NT’s
• AGONIST: A molecule
that mimics the effects of
a NT or blocks the
reuptake of a NT so the
effects are prolonged.
Agonists excited neurons.
• Ex: The venom of a black
widow spider acts as an
ACH agonist, leading to
painful muscle
contractions, convulsions,
and possible death
•
•
ANTAGONIST: A
molecule that inhibits a
NT release.
EX: Botulin, a poison
that can form in
improperly canned
foods, causes paralysis
by blocking ACH release
from a sending neuron.
(Botox works the same
way, reducing wrinkles.)
Research has shown that your mood
is influenced in part by the amount of
serotonin receptor binding. When you
are happy, it is likely that you have
more serotonin receptors activated.
Positive events in your life (like falling
in love, perhaps) cause greater
serotonin release, increasing receptor
binding.
After a little while the serotonin
molecule will detach ("unbind") from
the recepter and float back into the
synapse. When this happens, the
receptor stops sending chemical
signals to the cell body, and it waits
for another serotonin molecule to
come along.
(Those yellow things on the membrane of the axon terminal are
serotonin reuptake transporters.)
About an hour or so after you take Ecstasy
(the peak experience)
When you take
Ecstasy, the vesicles
release enormous
amounts of serotonin
into the synapse.
This significantly increases serotonin receptor binding (more
serotonin in the synapse means a greater chance for some of them
to bind to the receptors). This increased receptor activity leads to
significant changes in the brain's electrical firing and is primarily
responsible for the MDMA experience (i.e. empathy, happiness,
increased sociableness, enhanced sensation of touch, etc.).
Notice that there is
some dopamine in the
synapse as well (the
blue things).
MDMA also causes
dopamine release
(from dopamine
cells).
As you can see,
dopamine
receptors have also
been activated.
Long term effects
• Research has shown people who have once used
MDMA regularly have measureable degrade in
memory function, attention problems, and
impaired executive function such as decision
making and planning. They also measure within
range to be diagnosed with depression.
• Data is statistically significant (likely not due to
chance) BUT confounding variables such as
alcohol use and use with other drugs as well as
the fact that these a self-reports, not necessarily a
representative sample make it difficult to draw
causal conclusions.
ENDOCRINE SYSTEM
GLAND/ORGAN
LOCATION
FUNCTION
Hypothalamus
Pituitary gland
Brain
Brain
Controls the master gland, pituitary
Secretes many different hormones which
regulate the other glands
Thyroid
Neck
Controls metabolism
Adrenal glands
Attached to kidneys
Release adrenalin which regulates heart rate,
respiration, “fight or flight”
Pancreas
Near the stomach
Regulates level of sugar in the blood
Ovary
Lower abdomen of
women
Secretes female sex hormones
(estrogen/progesterone)
Testes
Testicles
Secretes the male sex hormone testosterone
ENDOCRINE SYSTEM
Hormones vs. Neurotransmitters
• Some hormones, like adrenaline, are chemically
like neurotransmitters. Therefore, hormones &
NTs function in very similar ways.
• They differ in processing speed: NTs communicate
very rapidly
and hormones move much more
slowly throughout the body.
• But even though it takes longer for hormones to
have their effect, the effect is often more long
lasting.
• Brain > pituitary gland > other glands > hormones
> brain
The BRAIN
The brainstem consists of the medulla, pons, and
reticular formation.
Part of the
brain
Location
Purpose/function
Medulla
(aka medulla
oblongata)
Top of the spinal
cord, located in
the skull
Basic life sustaining functions: heart beat,
breathing, vomiting , salivation, coughing, &
sneezing; damage here is frequently fatal
Pons
Anterior to (to
the front of) the
medulla
Reticular
formation
Within the
medulla & pons
Latin for “bridge”, origins of cranial nerves
that cross from left to right sides of the brain.
Involved with communication between the
cerebellum and the cerebral cortex.
Network of neurons that filters incoming
stimuli to other areas of the brain; controls
arousal
THE BRAIN
The thalamus sits atop the brainstem and the cerebellum is
located to the rear of the brainstem.
Part of the
brain
Cerebellum
Thalamus
Location
Purpose/function
Rear of
brainstem,
base of brain
top of
brainstem
“little brain” coordinates voluntary
movement, enables one type of
nonverbal learning & memory;
Receives information from all sense
(except smell) & routes to higher brain
regions; also receives info from brain that
goes to cerebellum & medulla
THE BRAIN
The limbic system lies on the border of the brain’s older
evolutionary parts and the most advanced cerebral
hemisphere.
Hypothalamus Below the
thalamus
Amygdala
Hippocampus
Monitors blood chemistry, controls the
pituitary gland (master gland); key to
motivated behaviors such as hunger, thirst,
sexual drive, fight or flight…
Top of brainstem Influences aggression and fear, activated by
emotions
Top of brainstem Keeps track of memories
THE BRAIN
The cerebral cortex is the outer layer of the brain’s
hemispheres. It is the body’s control and informationprocessing center.
Lobes
Occipital lobe
Parietal lobe
Temporal lobe
Frontal lobe
Purpose/function
Rear areas of the cerebral cortex; vision center
Top to rear area of the cerebral cortex; includes the sensory
cortex
Side area of the cerebral cortex (above ears); hearing
Front area of the cerebral cortex; speaking and motor
activities, higher order thinking such as planning, judging,
problem solving
OTHER CORTICAL AREAS
(Other areas of the cerebral cortex)
• Association area (cortex): any of the various
areas of the cerebral cortex that are not involved
primarily in sensory or motor function.
• Broca’s area: area of the frontal lobe associated
with the control of speech. (Think “boca”=mouth
in Spanish)
• Wernicke’s area: area association with the
interpretation of sound
• Aphasia: loss or impairment of the ability to
understand language or express oneself through
language due to injury or illness.
Illustration of brain structures involved
in making conversation.
The Anatomy of the Brain
• http://www.gwc.maricopa.edu/class/bio201/
brain/brshpx.htm
THE BRAIN
Corpus callosum
Left hemisphere
Right hemisphere
Band of neural fibers that connecting the two brain
hemispheres and carrying messages between them
Controls the right side of the body, primary location for
speech (Broca’s area), also specialized for math ability,
calculation, and logic
Controls the left side of the body, visual & spatial
relations, perception is primarily processed here, music &
art better understood on this side of the brain, creativity
and intuition are also found here.
THE BRAIN
• ** The idea that we are “left” or “right”
brained has been over simplified by “pop”
psychology articles. We all use both sides of
our brains and anyone who has sustained
damage to one or both sides of the brain
shows remarkable compensation made by the
opposing side.
• “wax on, wax off”
activity
BRAIN SCANS
Test
EEG
What does it stand for?
Electroencephalogram
Lesions
CAT
Computed tomography
PET
Positron emission
tomography
MRI/
fMRI
Magnetic resonance
imaging
How does it work?
Reading of electrical
waves traveling across
the brain
Removal or damage to
selected brain matter
When is it used?
Stimuli evoke electrical
impulses which will be
picked up by the EEG
Animal studies, biopsies,
removal of damaged
tissue
x-ray photographs
Identify head trauma,
fractures
Shows areas of chemical Research which parts of
“consumption” (glucose) the brains are active or
w/radioactive tracers
inactive by following the
tracers
Magnets align neural
See the soft tissue and
atoms which give off
fluid areas of the brain
signals when returning and the blood flow
to normal
BRAIN SCANS
GENETICS & HUMAN BEHAVIOR
Behavioral geneticists study our differences and
weigh the relative effects of heredity and
environment.
NATURE VS. NURTURE
Genetically, all humans are 99.9% identical. It is
the .1% in conjunction with varying
environmental factors that makes us all
unique.
Human traits are influenced by gene complexes
meaning multiple genes play a role in height,
intelligence, temperament, etc.
GENETICS & HUMAN BEHAVIOR
• TWIN STUDIES
Identical >>
Fraternal
Genetics & Behavior
• Identical twins share identical genes and very
similar developmental environments
• Fraternal twins share 50% of the same genes
and very similar developmental environments
• Separated identical twins share identical
genes but very different developmental
environments.
Genetics & Behavior
• Research shows that identical twins are much
more similar behaviorally than non-identical
twins.
• Lykken & McGue found that you are 5.5 times
more likely to divorce if your identical twin had
divorced.
• Loehlin & Nichols found identical twins to be
more similar in abilities, personal traits, and
interests, regardless of parental treatment.
Genetics & Behavior
• Genetically identical twins reared apart in different
families have consistently shown significant
similarities in personality, interests, and behaviors.
Those reared together are even more similar.
• Genetically identical twins reared apart have more in
common than fraternal twins reared apart.
• Though some researchers feel this may be all due to
“chance,” (Besides, how many sets of identical twins
reared apart actually exist?) adoption studies
strengthen the genetic argument in that adopted
children are often NOT similar to their adoptive
parents.
Nature vs. Nurture
• “Nurture works on what nature endows.”
• Example: Some people are physiologically more
prone to eating disorders, but the
environment/culture to which they are exposed
can/will enhance their chances or developing an
eating disorder.
• What implications does knowing one’s genetic
make up and “risk” factors have for our future?
Behavioral geneticists vs. Evolutionary
psychologists
• Behavioral geneticists are interested in what
makes us unique and in how and why we
differ from one another.
• Evolutionary psychologists focus on how we
are alike as humans, what commonalities we
share.
– All people in all cultures show favor to sweet and
fatty foods because the consumption of these are
beneficial to survival of famine. Unfortunately,
today famine is not often a risk factor, yet we still
are driven to consume fatty foods >> obesity.
Mean Genes is a book
by Drs. Terry Burnham
and Jay Phelan that
explores the genetic
explanations for our
behaviors such as
spending habits, eating
habits, intimacy, and
mating.
Environmental Factors
• Prenatal environment: prenatal care, placentas, etc.
• Enriched environment: “Those with the most toys
win!” Without exposure to written or signed
language prior to adolescence one will never master
it.
• Parenting: Has its greatest influence when extreme
(abusive, neglectful, etc.)
• Peer Influence: The selection of peers makes it
powerful. A child is more likely to become a smoker if
peers smoke but not if parents smoke.
• Parent decisions (like where to live) will influence peer
selection.