use transient gene therapy to mutate a light sensitive channel into the relevant neurons, guide an optical fiber to the area and trigger via light coupled into the fiber.That is as precise as we can make the targeting of the mutation, and does not cause scaring. Even if some of the vector goes where it is not supppsed to there is litte light inside a skull...

The biggest problem is neural rewiring as response to the unnatural stimulus and ethics comitees.