The title more or less says it all, but to contextualise a bit:
Cerebellar molecular layer interneurons have been classified, probably since Cajal, into the basket cells, which synapse onto the soma and axon initial segment of Purkinje cells, and stellate cells, which synapse onto the dendrites. The types are distinguishable in tissue slices by positional and morphological differences, but it is at least arguable that the variation is continuous and the boundary somewhat arbitrary. Both types take basically the same inputs and deliver the same outputs, albeit in marginally different cellular locations.
As far as I'm aware -- and I would be incredibly happy to be told otherwise -- there is no known difference in protein expression that can be used to distinguish between these interneuron types, for instance in dissociated culture.
So, is there in fact some identifying marker? And if not, is it still useful to classify them as separate types?