How does a neuron change its characteristics in order to change its function, without changing its connections with the neural networks? Basically, do any organelles change their properties and are there any major chemical modifications that could cause it and explain it?

I tried looking everywhere on the internet but I couldn't find any, perhaps neuroscientists still don't know yet.

My initial idea was that some changes of some organelles inside the neuron caused the change in function of the entire neuron. Or that there were some chemical changes that could cause the presence of a molecule that controls the global function of the neuron more than some other.

Thanks a lot for your help and answers.