Final answer:
Axo-axonic synapses typically modulate other synapses and do not directly generate an action potential. Action potentials are most often generated at the axon hillock, where summation of graded potentials occurs.
Step-by-step explanation:
In the context of the central nervous system (CNS) and its synaptic connections, such as axosomatic, axodendritic, and axo-axonic synapses, the question pertains to which of these synapses does not affect action potential (AP) generation. While each type of synapse connects to different parts of a neuron—axons to the soma (cell body), dendrites, or other axons—it's axo-axonic synapses that are primarily associated with modulating the effects of other synapses rather than generating an AP directly. Therefore, axo-axonic synapses typically do not produce postsynaptic potentials that lead directly to the generation of an AP. The generation of an action potential usually begins at the axon hillock or initial segment of a neuron, where a high density of voltage-gated Na+ channels are located. This is where graded potentials summate to reach the threshold for firing an action potential.