Understanding Action Potentials and Synaptic Transmission in Neuroscience - Prof. Thomas F, Study notes of Psychology

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Goals for Today
How to create action potentials  "The signal" to communicate in synapsis  Ionic basis of the "decision"
The process of synaptic transmission  How on neuron can change the voltage of another  Go from chemical signal to electric and back
The major neurotransmitters of the brain  List major players  Action Potential Is when the SOMA adds together grading potentials!! o Hyperpolar = negative o Depolar = positive (a) A graded potential starts above threshold (1) at its initiation point, but decreases in strength as the cell body. At the trigger zone it is below threshold and therefore does not initiate an action pot No action potential 
the receptors do the conversation from electrical to chemical
chemical binds to receptors that creates a graded potential that brings it back to electrical.
Postsynaptic potentials (graded potential caused by the release of neurotransmitters)
IPSP
hyperpolar
Cl- channel opens
makes cell more negative
inhibits AP generation
Cl- floods into the cell
adding - in the cell
brings charge way too neg to reach thresh
EPSP (excititory)
depolar
creating an AP
Na+ coming into the cell
adding + in the cell
closer to threshold
Terminating transmission
Chemical Degadation
job is to destroy neurotransmitter
Re-uptake (most common way to terminate)
Neuron takes neurotransmitter back to be used again
Transporter
Senses NT in the gap, it sucks it back into the cell
Neurotransmitter
Ionotropic
FAST
Ion channel with receptor attached directly to it
They are the same thing ultimately
So channel opens very quickly
Metabotropic
SLOW
Receptor and channel are different units
NT binds to receptor
causes a chemical reaction within the cell
Second message
Second message goes from receptor to the channel
Fast/Slow potentials
Ionotropic : Faster onset and decay (miliseconds)
Metabotropic : Slower onset and longer lasting (seconds)
Keeps cell nearer to Thresh (EPSP) so you can excited faster and with less effort
MAJOR neurotransmitters
Amino acid receptors are primarily ionotropic:
Glutamate : EPSP
Main fast excitable neurotransmitter
GABA: IPSP
Main fast inhibitor neurotransmitter
Acetylcholine has both ionotropic and metabotropic receptors:
Ionotropic = "nicotinic" (nicotine)
Nerve-muscle junction
Metabotropic = "muscarinic"
in the brain, especially the cortex
Important for learning, makes it easier to learn
Monoamine receptors are mostly metabotropic
Serotonin
Dopamine
Norepinephrine
Epinephrine
Monoamine receptors are mostly metabotropic
Slow regulation of brain activity important for arousal and mood
Your mood changes slowly
YOUR BRAIN IS LIKE A CHEMICAL SOUP!!! YUMM!!!
10/04/2012