Summation and Integration

Why is summation of EPSPs typically required in a post-synaptic neuron?

one action potential in the pre-synaptic neuron releases very little neurotransmitter. Not enough to generate an action potential in the post-synaptic neuron. Therefore, summation of EPSPs is required to reach threshold.

What is the summation of EPSPs?

occurs when two or more EPSPs are produced simultaneously and add on top of one another to produce a larger EPSP.

What are the two ways that summation can occur in a neuron?

temporal and spatial

Describe temporal summation.

the summation of multiple EPSPs produced from a single synapse. This happens when the same pre-synaptic neuron produces many consecutive action potentials and releases many vesicles worth of glutamate.

Describe spatial summation.

is the summation of multiple EPSPs produced from different synapses simultaneously. This occurs when different presynaptic neurons produce action potentials and release glutamate simultaneously.

What is synaptic integration?

is the process that determines if a post-synaptic neuron generates action potentials and, if so, how many. It is how decisions are made and information is processed in the nervous system

What determines whether or not a post-synaptic neuron produces action potentials?

depends on the sum of all excitatory and inhibitory pre-synaptic neurons that synapse with it.