Ultimately, thinking about language in the brain, like thinking about sentence processing and language acquisition, will change the nature of linguistic theory and brain science. Proposals take on new dimensions as we find new ways of making theories responsible to data. We know that similarity can cause interference in some experimental paradigms whereas identity usually primes or facilitates. One can imagine, then, linguistic paradigms in which one might tease apart identity and similarity and investigate the neural coding of identity. Neuron firing can be conceived of as digital or analog.
Linguistic computation has crucially digital properties.
One can model apparently all or nothing behavior as a limiting case of analog processing, but there is no particular reason to suppose that biological systems are analog. This goes for brain research, of course. Fodor on brain mapping. Here, depends first on what we already might know about an area. Once we have identified areas that seem responsible for certain functions, we can apply the logic of the derivational theory of complexity, i.e., the logic of cognitive science, and ask further questions about the way that the area performs the function.