Do you have a specific area in mind? Robotics, Brain Computer Interfaces, Network models, complex systems, bioinformatics, bio/neuro statistics etc...? It's a vast field with many open questions and opportunities. If you have a bias towards some specific area then it might save you a lot of exploring other fields which might not be interesting to you. I recommend checking
this page, and going through the current projects. It will give you a good idea of what kind of problems computational neuroscience tries to address and which sub-field/topics you have a bias towards.