Thanks for your comment. Off the top of my head, I cannot think of any study that has looked at the neural development of prediction error coding by dopamine neurons. Indeed, to my knowledge, we only have one study that has looked at how the coding of prediction error appears while learning a task (Coddington & Dudman, Nature Neuroscience)
As for the loss of dopamine neurons, we do have some studies looking at how learning from reinforcement might be altered in patients with Parkinson’s disease. Results are mixed: earlier studies found a clear effect; a comprehensive study in 2017 found none.