Transcript Brain

Physiology & Behavior
Neurotransmission
Jette Hannibal - Inthinking
Standard/Learning Outcome B6
USING ONE OR MORE EXAMPLES, EXPLAIN THE
EFFECTS OF NEUROTRANSMISSION ON HUMAN
BEHAVIOR
DEFINE THE COMMAND TERM
Jette Hannibal - Inthinking
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The nervous system
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NS: gathers and processes information, produces responses to
stimuli, coordinates the workings of different cells
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CNS (brain + spinal cord): receives, processes, interprets, and
stores incoming sensory information (e.g. Taste, state of internal
organs)
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PNS: deals with input and output of CNS through sensory and motor
neurons.
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The nervous system
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Neurons: basic structural unit of NS
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Communication between neurons:
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electric conduction
chemical transmission
A large concentration of neurons in the
brain and the spinal cord.
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80% are found in the brain’s Cerebral cortex
Structure of neurons
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Cell body or nucleus (contains DNA)
Dendrites:
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Axons:
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the cell body.
Terminal buttons:
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information transmission
storage of neurotransmitters.
Synaptic gap:
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between dendrites and terminal buttons.
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Where neurotransmitters “pass” information from neuron to
neuron.
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Neuron
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http://learn.genetics.utah.edu/content/addi
ction/reward/neurontalk.html
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Neuronal communication
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Within neurons: Action potential
Between neurons: Synaptic transmission
of neurotransmitters
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Action potential
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Electro-chemical messages
AP occurs when a neuron sends
information down an axon
AP caused by an exchange of Sodium and
Potassium ions across the neural
membrane
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Neurotransmitters
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Chemical messengers from neuron to
neuron.
Messages may also travel from neurons to
to muscles and organs in the body, such
as lungs or the intestines.
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Synaptic gap
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Synaptic vesicles with neurotransmitters at
one side of the gap (terminal buttons): presynaptic gap. Like “keys”
Receptor sites for neurotransmitters (like
locks) at the other side of the gap: postsynaptic gap
1/10000 of a second to travel across the
synaptic gap
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Neurotransmitters
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Brief intro to principles of
neurotransmission
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Intro to Neurotransmission
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Neurotransmitter processes
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Excitatory: increases the frequency of action
potential
Inhibitory: decreases the frequency of action
potential
De-activation: effect of neurotransmitter
stopped (destroyed by special enzyme)
Re-uptake: reabsorbed by the terminal buttons.
Drugs can inhibit re-uptake so that the
neurotransmitter remains longer in the synaptic
gap
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Examples of neurotransmitters
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Dopamine: (inhibitory) Controls arousal levels in the
brain; vital for physical motivation (e.g. associated with
craving in addiction)
Serotonin: (inhibitory) Controls mood and anxiety levels
High levels of serotonin are associated with optimism.
Acetylcholine (ACh): (excitatory) Controls activity in the
brain connected with attention, learning and memory
Noradrenaline: (excitatory) involved in mental arousal
and elevated mood
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Dopamine and serotonin
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The reward pathway - dopamine
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Stimulation of the
reward center is
linked to release of
dopamine
Rats will continuously
press a lever that
gives a small
electrical stimulation
to the pleasure center
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A Song to Help
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http://www.youtube.com/watch?v=XP9IEo
Cw5W4&safe=active
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