Transcript Problems with Imbalance

Biopsychology
How Are Genes and
Behavior Linked?
Evolution has fundamentally
shaped psychological
processes because it favors
genetic variations that
produce adaptive behavior
How are Genes and Behavior
Linked?
• Evolution –
The gradual process of biological change that
occurs in a species as it adapts to its
environment
• Natural Selection
Adaptations occur as a result of random gene
mutations
– Adaptive gene mutations passed to next generation
– Non-adaptive gene mutations less likely to be passed
on
Genes and Inheritance
• DNA (deoxyribonucleic acid)
– biological instruction for building organisms
• Chromosomes
– Consist primarily of DNA
– Contain genes and instructions for how genes are
expressed
• Genes
– Segments of DNA that provide a blueprint for making
proteins
– Proteins are the building blocks of the organism
Genes and Inheritance
• Variation in traits results from sexual
reproduction
• 23 pairs of chromosomes
– Get one half of each pair from each parent
– One pair is specialized and codes for sex
– XX = Female
– XY = Male
– * Father determines the sex of the child
Genes and Inheritance
• Specific genes inherited from each parent
varies due to random cell division
– Like a lottery where all of mother’s or father’s
traits are available and randomly select ½ of
them
– Explains why you do not look or act exactly
like your siblings
Genes and Inheritance
• Genotype – blueprint for traits
(both physical and psychological)
• Phenotype – an organism’s
observable physical characteristics
– Is a function of genetic
makeup and also
environmental influences
How do we Study the Impact of
Genetics on Behavior?
• Identical Twins  share 100% of genes; shared
prenatal environment
• Fraternal Twins  Share 50% of genes; shared
prenatal environment
• Twin Studies
– Identical twins (share 100% of genes) reared together
or apart  any variation due primarily to environment
– Identical twins vs fraternal twins (share 50% of genes;
reared together)  any variation due primarily to
genetics
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
The Neuron
• Types of Neurons
– Sensory neurons (carry messages from
sense receptors towards the CNS)
Motor neurons (carry messages from
CNS toward muscles and glands)
Interneurons (carry messages
between nerve cells)
The Structure of a Neuron
Neural Communication
• Two states
– Resting Potential  Negatively charged ions on
inside; positively charged ions on outside; cell is
negatively charged on inside relative to outside
– Action Potential  cell depolarizes; i.e., cell becomes
positively charged
– Voltage change (electrical surge) travels down axon
and causes release of neurotransmitter into the
synapse
Neural Communication
• All or None Law
– Neurons either fire or they don’t
– Require a minimum amount of excitation or
stimulation in order to fire
– Once the minimum threshold has been
reached, the neuron will fire
– Based on summation of excitatory and
inhibitory signals
Neural Communication
• Once the neuron fires, it releases its
Neurotransmitter into the synapse
– Neurotransmitter  Chemical messengers that relay
neural messages across the synapse
• Neurotransmitter fits in receptor like a key fits in
a lock
• Neurotransmitter either excites or inhibits the
post-synaptic cell by binding to its receptors
Neuron
Demonstration
Neural Communication
• Methods to stop neural transmission
– Reuptake
– Degradation
– Presynaptic autoreceptors
Seven Important
Neurotransmitters
Dopamine
Serotonin
Norepinephrine
Acetylcholine
GABA
Glutamine
Endorphins
Normal Function:
Dopamine
Serotonin
Norepinephrine
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
Normal Function:
Dopamine
Serotonin
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)
Normal Function:
Dopamine
Serotonin
Norepinephrine
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
Normal Function:
Dopamine
Serotonin
Norepinephrine
Acetylcholine
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
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
Dopamine
Normal Function:
Norepinephrine
Primary excitatory
neurotransmitter in CNS;
involved in learning and
memory
Acetylcholine
Problems with Imbalance:
Serotonin
GABA
Glutamine
Endorphins
Brain damage after stroke
Substances that Affect:
PCP (“angel dust”)
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
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
The Organization of the
Nervous System
Nervous system
Peripheral nervous
system
Autonomic
nervous system
Sympathetic
nervous system
Central nervous
system (CNS)
Somatic
nervous system
Parasympathetic
nervous system
Divisions of the Nervous System
• Central Nervous System (CNS)
– Brain and spinal cord
• Peripheral Nervous System (PNS)
– Connects brain and spinal cord with
the rest of the body
Peripheral Nervous System
• Somatic Nervous System
– Carries incoming messages from sense organs
– Carries outgoing messages to skeletal muscles;
mobilizes voluntary movements
• Autonomic Nervous System
– Carries signals from the CNS to the internal
organs
– regulates involuntary functions such as digestion,
respiration, heart rate
Autonomic Nervous System
• Sympathetic Division
– Mobilized under stress – (e.g., controls 4 F’s)
• Increases heart rate and respiration, increases
muscle tension, shuts off digestion
• Parasympathetic Division
– Responsible for basic processes or
homeostasis
• Slows heart rate and respiration, increases
digestive functioning
Example
• Hear rattlesnake
– Somatic NS  orients eyes to sound to locate
snake
– Sympathetic Division of ANS  mobilizes fight or
flight response (i.e., blood to skeletal muscles;
increases respiration)
– Somatic NS  initiates skeletal muscles to escape
– Once escaped, Parasympathetic NS initiates
relaxation response
The Endocrine System
(the body’s chemical messenger system)
The Endocrine System
• Pituitary gland
– Master gland; i.e., produces
hormones that influence the
secretions of all other endocrine
glands
– Attached to and controlled by
hypothalamus
The Endocrine System
• Endocrine glands release hormones into
bloodstream; circulate through body until target
organ is reached
• Non-stress conditions  supports
parasympathetic nervous system in maintaining
basic processes or homeostasis
• Stress conditions  supports sympathetic
nervous system through release of epinephrine
(adrenaline)
The Endocrine System
Glands
Systems/ Processes regulated
Anterior Pituitary
Ovaries and Testes, Milk production,
metabolism, stress reactions
Posterior Pituitary
Conservation of water, milk secretion, uterus
contractions
Thyroid
Metabolism, physical growth & development
Parathyroid
Calcium levels
Pancreas
Glucose (sugar) metabolism
Adrenal glands
Fight or flight response, metabolism, sexual
desire (especially women)
Ovaries
Female sex characs., production of eggs
Testes
Male sex characs., sperm production, sexual
desire
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
Film on Structures of the Brain
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
The Brain Stem and Cerebellum
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•
•
•
•
Thalamus
Pons
Cerebellum
Medulla
Brain stem
The Limbic System
• Hypothalamus –
Serves as the
brain’s bloodtesting
laboratory,
constantly
monitors blood to
determine the
condition of the
body
The Limbic System
• Amygdala –
Involved in
memory and
emotion,
particularly fear
and aggression
The Limbic System
• Hippocampus –
Involved in establishing
long-term memories
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
• Cerebral hemispheres –
The two walnut shaped halves of the
cerebrum, connected by the corpus
callosum
Phineas Gage
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
• Feelings of anxiety
• Positive emotion
• Repetitive but not
spontaneous
speaking
• Responses to simple
commands
• Facial recognition
• Memory for shapes
and music
• Spatial interpretation
• Emotional
responsiveness
• Negative emotion
Film on Split-Brain