Physiology & Behavior
Neurotransmission
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USING ONE OR MORE EXAMPLES, EXPLAIN THE EFFECTS OF NEUROTRANSMISSION ON HUMAN BEHAVIORDEFINE THE COMMAND TERM
Standard/Learning Outcome B6
Jette Hannibal - Inthinking
Jette Hannibal - Inthinking
The nervous system
NS: gathers and processes information, produces responses to stimuli, coordinates the workings of different cells
CNS (brain + spinal cord): receives, processes, interprets, and stores incoming sensory information (e.g. Taste, state of internal organs)
PNS: deals with input and output of CNS through sensory and motor neurons.
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The nervous system
Neurons: basic structural unit of NS
Communication between neurons: electric conduction chemical transmission
A large concentration of neurons in the brain and the spinal cord. 80% are found in the brain’s Cerebral cortex
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Structure of neurons
Cell body or nucleus (contains DNA) Dendrites:
information transmission Axons:
the cell body. Terminal buttons:
storage of neurotransmitters. Synaptic gap:
between dendrites and terminal buttons. Where neurotransmitters “pass” information from neuron to
neuron.
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Neuron
http://learn.genetics.utah.edu/content/addiction/reward/neurontalk.html
Jette Hannibal - Inthinking
Jette Hannibal - Inthinking
Neuronal communication
Within neurons: Action potential Between neurons: Synaptic transmission
of neurotransmitters
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Action potential
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
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
Synaptic vesicles with neurotransmitters at one side of the gap (terminal buttons): pre-synaptic gap. Like “keys”
Receptor sites for neurotransmitters (like locks) at the other side of the gap: post-synaptic gap
1/10000 of a second to travel across the synaptic gap
Neurotransmitters
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Jette Hannibal - Inthinking
Brief intro to principles of neurotransmission
Intro to Neurotransmission
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Neurotransmitter processes
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
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
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
A Song to Help
http://www.youtube.com/watch?v=XP9IEoCw5W4&safe=active
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