If we're talking about a network function that's related to movement, we are interested in placing these electrodes in movement associated areas of the brain, deep gray structures called the basal ganglia, which can be seen over here.
Deep structure and surface structure (also D-structure and S-structure, although these abbreviated forms are sometimes used with distinct meanings) are concepts used in linguistics, specifically in the study of syntax in the Chomskyan tradition of transformational generative grammar.