Yeah, they're needed everywhere around the world. But the pay is less in developing countries. When you have loans and a family to care, things become more difficult.
There is definitely a demand for more doctors in Africa, and if that's where you want to be, you can approach hospitals and international aid organizations to find opportunities after you finish medical school. You can look into doing internships with programs like http://www.msf.org/ if you want to be in Africa, but I'm not sure how much neurosurgeon-specific experience you'll get there. Definitely consider where you want to live, as the medical system is different in each country, so you will have a very different experience in South Africa relative to Egypt or relative to Kenya.</body></html>
If you want to just visit the country and practice temporarily, then you can join an organization such as Doctors Without Borders and practice under your US license.