Is doing residency in neurosurgery and getting a PhD in neuroscience feasible?

Hi,I’m a 3rd year med student in Italy.I’ve always been interested in the inner workings of the brain and I think that’s the path I’d like to take. Undoubtedly, I’ll want to do residency after med school and I was thinking that neurosurgery might be a good option since it’s a good combination of my passion for neuroscience and my interest in surgery.At the same time though,I’d love to actively partecipate in the field of researching the brain and how it works,so my question is: Is it feasible to do residency in NS and get a PhD in neuroscience as well? Which one would I have to complete first? Moreover,I was interested in maybe getting my PhD in Japan,since it’s particularly known for great academic opportunities,especially in neuroscience (plus I like japanese culture). Thanks in advance.