The brain is not wired with few enough interactions to actually isolate a network like that. The number of connecting synapses is massive, outnumbering neurons by 100-1000x. And more importantly, the connections are spread all over the place.

E.g., when I was in grad school for neuroscience, I attended a multimodal sensory symposium where I learned that huge numbers of neurons in primary sensory cortices (V1, A1, etc) responded to stimuli from other senses. E.g., 20% of your primary visual neurons fire when you get auditory stimuli.