BIOPSYCHOLOGYEverything 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
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
The path of the electrical
impulse (action potential) thru
neuron
C. myelin
sheath
Layer of fatty tissue that insulates
the axon of some neurons
Speeds the electrical impulse
down the axon; degenerated
by multiple sclerosis
D. axon
terminal
The end of the neuron Upon stimulation it released
neurotransmitters into the
synapse or takes them back up
(reuptake)
E. synapse The tiny gap between dendrites and
axon terminals
The space btw where the
neurotransmitters move from
axon terminal to dendrites
F. vesicles Tiny, near spherical packets within
the axon terminal that contain high
concentrations of neurotransmitters
Stores the NT until the action
potential triggers its release
into the synapse
Neurons: the cells that make up the nerves
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 potentialtravels 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.
NeurotransmittersNeurotransmitter Effect
Norepinephrine Helps control alertness and arousal; compliments adrenalin
Epinephrine 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
Acetycholine (ach) 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.
Dopamine 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.
Serotonin Affects mood, hunger, sleep, and arousal. Prozac and similar anti
depressants raise serotonin activity and reduces feelings of anxiety.
GABA NT that functions almost always as an neural inhibitor; it helps you
to relax. Alcohol and enhance GABA and bring on sleep.
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 SYSTEMGLAND/ORGAN LOCATION FUNCTION
Hypothalmus Brain Controls the master gland, pituitary
Pituitary gland Brain 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 BRAINThe 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
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.
Reticular
formation
Within the
medulla & pons
Network of neurons that filters incoming
stimuli to other areas of the brain; controls
arousal
THE BRAINThe thalamus sits atop the brainstem and the cerebellum is
located to the rear of the brainstem.
Part of the
brain
Location Purpose/function
Cerebellum Rear of
brainstem,
base of brain
“little brain” coordinates voluntary
movement, enables one type of
nonverbal learning & memory;
Thalamus top of
brainstem
Receives information from all sense
(except smell) & routes to higher brain
regions; also receives info from brain that
goes to cerebellum & medulla
THE BRAINThe limbic system lies on the border of the brain’s older
evolutionary parts and the most advanced cerebral hemisphere.
Hypothalamus Below the
thalamus
Monitors blood chemistry, controls the
pituitary gland (master gland); key to
motivated behaviors such as hunger, thirst,
sexual drive, fight or flight…
Amygdala Top of brainstem Influences aggression and fear, activated by
emotions
Hippocampus Top of brainstem Keeps track of memories
THE BRAINThe cerebral cortex is the outer layer of the brain’s
hemispheres. It is the body’s control and information-processing center.
Lobes Purpose/function
Occipital lobe Rear areas of the cerebral cortex; vision center
Parietal lobe Top to rear area of the cerebral cortex; includes the sensory
cortex
Temporal lobe Side area of the cerebral cortex (above ears); hearing
Frontal lobe 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 BRAINCorpus callosum Band of neural fibers that connecting the two brain
hemispheres and carrying messages between them
Left hemisphere Controls the right side of the body, primary location for
speech (Broca’s area), also specialized for math ability,
calculation, and logic
Right hemisphere 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 SCANSTest What does it stand for? How does it work? When is it used?
EEG Electroencephalogram Reading of electrical
waves traveling across
the brain
Stimuli evoke electrical
impulses which will be
picked up by the EEG
Lesions Removal or damage to
selected brain matter
Animal studies, biopsies,
removal of damaged
tissue
CAT Computed tomography x-ray photographs Identify head trauma,
fractures
PET Positron emission
tomography
Shows areas of chemical
“consumption” (glucose)
w/radioactive tracers
Research which parts of
the brains are active or
inactive by following the
tracers
MRI/
fMRI
Magnetic resonance
imaging
Magnets align neural
atoms which give off
signals when returning
to normal
See the soft tissue and
fluid areas of the brain
and the blood flow
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 complexesmeaning 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.