How can I claim ownership of my idea without securing a patent? I created a model for the pathogenesis of a neurodegenerative disorders that reveals a novel target for neurorestoration/neuroprotection. Can I patent the use of an existing compound for another purpose since I have reason to believe it would also act to target neurodegeneration in this disease?

To provide some background, I'm a recent Ivy League alum who hasn't been able to secure a long-term position in a lab (in grad school or as a job). I've done an extensive analysis of the literature and believe I've found a number of solid papers to support my claim but, of course, since my clout in research is nonexistent, I'm not sure what to do. My advisor who supervised this work is still saying we can publish the manuscript where I explained my model this summer but I'm afraid that if there's multiple people on the paper, some of whom are bigger names in the fields of biochemistry, neurodegeneration, and medicine than me, it'll look like it wasn't completely my idea. 

Should I use a preprint server, a provisional patent (even though I can't afford the full $5000 patent that you need to protect your patent status.), or ask one of the potential co-authors directly what she thinks (she's huge in the field of neurodegeneration)? I'm not trying to sound self-important, I'm just really anxious to capitalize on my effort, which involved a lot of work, before someone else does. How important does someone have to be in molecular neurobiology for a new idea from them to be taken seriously?
You can't patent that.


  Can I patent the use of an existing compound for another purpose since I have reason to believe it would also act to target neurodegeneration in this disease?


No, you can't patent "the use of X for purposes of Y" abstractly. As this description of patentable matter explains it:


  A patent cannot protect an idea. Instead, the idea must be embodied in one or more of the following:
  
  
  A process or method (such as a new way to manufacture concrete)
  A machine (something with moving parts or circuitry)
  A manufactured article (such as a tool or another object that accomplishes a result with few or no moving parts, such as a pencil)
  A new composition (such as a new pharmaceutical)
  An asexually reproduced and new variety of plant.
  


If you developed a specific method to use compound X to do neurorestoration/neuroprotection of Y - then maybe you can patent it.

Instead of trying to patent - try scientific publication!

You need the anxiety to "capitalize on your effort". Like you, I have not been able to secure a position in academia - not even a temporary one - despite having a bunch of solid ideas which can be developed. So I can sympathize, at least somewhat. Still: You should not, must not, utilize the tool of patents - which is a legal mechanism for inhibiting scientific discovery and preventing the public from benefiting from inventions.

Instead, try to find the time to write a paper - albeit a "vision paper" rather than an empirical study - making your case. Perhaps publish it on arXiv before it's peer-reviewed, to "stake your claim" scientifically rather than capitalistically. It might help you find a source of funding for developing this idea - in a "start-up", an established company or even a scientific institution.