Hi Mangilal Bhagirath , Its is a very elaborate process, you cannot do neurology or cardiology just like that after your 12th grade and its not just specialisation, it is a superspecialisation course,and you must do your MBBS,MS/MD first (or its equivalent in other countries) ,it is easy to get mbbs in countries like China, Russia etc after your 12th grade, but if you want in good countries like UK,US,CANADA, it is gonna be really hectic. so i would suggest you to do your MBBS in india and then clear exams like USMLE or PLAB or AMC or NZREX and get into the speciality of choice ,but dont fixate on a speciality now, do your mbbs first and your options may change with exposure to that branch, keep an open mind, good luck