Hi all. I'd like to know whether the neuron of my interest is collateral or not. When I inject fluorescent protein-expressing virus in a certain brain region, it seems to show its terminal in two sites (Let's say site A and site B).

I wonder whether each one of them is neural terminal or the section of axon bundle tract. I am planning to use different virus such as Con/Fon virus and retrograde cre and flp virus but I wonder whether ihc can indirectly ressolve my question. Is there any protein marker that specifically locates in the axon terminal but not the axon itself or the other way around? If so I can stain by immunohistochemistry and see the colabelled fluorescence from the virus expression. I'd appreciate any comment!