PHGY 209 Lecture Notes - Lecture 19: Excitatory Postsynaptic Potential, Inhibitory Postsynaptic Potential, Excitatory Synapse
21 Feb 2018
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Summary of last lecture: action potential begins at initial segment and propagates down axon to pre-synaptic terminal, all-or-none event: begins when threshold reached at the initial segment. This begins with the synapses which occur mainly at the dendrites. Spine synapse: pre-synaptic terminal makes a synapse on a special structures called spines (protrusions on dendrites) Many spines and spine-synapses on the dendrites. Shaft synapse: synapses between the spines of the dendrites; mainly inhibitory synapses which balance out the excitatory synapses and inhibit the activity of the post synaptic neuron. The entire dendritic tree is covered in synapses: axosomatic: synapses on the cell body of neurons, often inhibitory synapses. Axodendritic and axosomatic synapses receive information from other neurons and relay that information down axons as action potentials. The next is a different category of synapses: axoaxonic: the pre-synaptic terminal of one axon makes a synapse with the pre-synaptic terminal of another.
