What can I do related to neuroscience with a bachelor's or master's degree?

Basically, I’m thinking about switching from MechE to something to do with neuroscience or cognitive psychology or something. “Wow that’s a total 180,” yeah, I know :))

Is there any way that I can major in something related to these without getting a PhD? I think it would be cool to do neurological research but I would rather not have to go through 6 extra years of school for it. If you have any suggestions that would be great!