Bienvenue dans la Zone d’entraide !

Hi OrAutonome,
Thanks for your question!
Synaptic pruning occurs in the brain before adulthood. It consists in the elimination of extra synapses (conections that are no longer needed). Synaptic pruning allows a more efficient and complex processing of information.
(See https://www.healthline.com/health/synaptic-pruning)

Myelination is the formation of a layer of myelin around the axon (the long threadlike part of a neuron).
As you can see, instead of being a single long sheath around the entire axon, myelin forms sheath in segments, which are separated by nodes of Ranvier.
This structure in segments alllows saltatory conduction, the jumping of action potential from one node of Ranvier to another. Therefore, the propagation of action potential will be faster compared to a unmyelinated neuron.
(See https://en.wikipedia.org/wiki/Myelin)
Hope this answers your question:)
Kylan