Spatial and temporal summation of local potentials at the axon hillock is critical to determining whether an action potential will fire or not. However, they are arithmetic processes that cannot increase the likelihood of an action potential occurring. The neuron has developed the ability to amplify local potentials so to increase the likelihood of an action potential occurring by the following mechanisms: 

-Generating larger postsynaptic potentials at synapses located farther away from the axon hillock, 
-Dendritic integration zones, which integrate local postsynaptic potentials prior to their arrival at the axon hillock, and
-Glial cells, which prevent released neurotransmitters from escaping the synaptic cleft and thereby increasing the strength of neurotransmitter stimulation. 

Amplifying Local Potentials

Local potentials are graded responses that diminish with increasing time and distance from the point of stimulation. Local potentials may be a form of postsynaptic potential.  

Brandeis University

The fact that a stronger stimulus elicits a stronger signal. If there are a greater number of EPSPs compared to IPSPs , a stronger signal will be sent compared to if there were an equal amount.

Graded Response

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

Spatial summation is the convergence of postsynaptic potentials coming from different locations. Temporal summation is the convergence of postsynaptic potentials that arrive at different periods of time, but close enough such that the summation is strong.

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