Our understanding of the neural tissue of the brain - as well as what it's actually doing are so poor, and the needs of what we're doing so different that there's a greater chance that our understanding of neural tissue is improved by developing our understanding of deep learning than the other way around.

To put it in bird flight analogy, by constructing airplanes and making it an exact science, we're able to get a much finer understanding of the pricipal problems in flight and get to appreciate the difference between the flight of colibris and bumblebees (who can't fly by gliding but must beat their wings frenetically) versus larger birds (which can fly by gliding, more closely resembling plane flight).