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General Psychology Neurology
Sarah Rach-Sovich
A quick review…
• Neural communication– Build from billions of interconnected cells– Name this cell
Neuron
???
What is my name?
Dendrites
Axon
Myel in Sheath
Terminal Branches
of Axon
Cell Body
Parts of a Neuron
• Cell Body: life support center of the neuron.• Dendrites: branching extensions at the cell body.– Receive messages from other neurons.
• Axon: long single extension of a neuron• Myelin sheath: covers the axon to insulate and
speed up messages through the neurons• Terminal Branches of axon: branched endings of
an axon that transmit messages to other neurons.
Synapse
• Junction between the axon tip of the sending neuron and the dendrite
• Tiny gap is called the synaptic gap or cleft
Neurotransmitters (NT)
• Released from the sending neuron
• Travel across the synapse and bind to receptor sites on the receiving neuron
• This influences it to generate an action potential
Reuptake
• NT in the synapse are reabsorbed into the sending neurons through this process
• Applying the brakes
How do they influence us?
• Serotonin pathways are involved with mood regulation
• Can I bum at neurotransmitter?
If only it were that simple…
•NTs do affect mood
•Utilization of drugs
Dopamine Pathways
• Involved with diseases such as schizophrenia & Parkinson’s disease
NTs and their functions
Lock & Key Mechanism
NTs bind to the receptors of thereceiving neuron in a key lock mechanism.‐
Agonist
Antagonist
How about an example?
•Marijuana (and others such as nicotine and cocaine) primarily affect the brain’s limbic system (also called the ‘reward system’)•Under normal circumstances pleasurable experiences are followed by the release of the NT dopamine which creates feelings of pleasure
How do you feel when something good happens?
• Your limbic system at work• Natural pleasures are necessary for survival– Food, water, sex
• Limbic system creates an appetite that drives you to seek those things
First time use of a drug
– Unnaturally intense feelings of pleasure– Limbic system is flooded with dopamine– The brain starts changing• There is more than enough dopamine• Neurons begin to reduce the number of dopamine
receptors• Neurons may make less dopamine in the brain (down
regulation)• Some neurons may even die
What if a person keeps using?• How many times can a person use
drugs without changing his or her brain and becoming addicted?
• Addicted limbic system craves the drug (made worse because of down regulation)
• Without the drug, the dopamine levels in the brain are low– Feels flat, lifeless, depressed,
joyless• Larger amounts of the drug are
needed (tolerance)
Questions?
A little advice to leave you with…