This is a very important concern. Tech companies already exert entirely too much power over society through smart phones and their accompanying apps. The damage they would do with direct access to your neurons is incalculable.
The only thing that comforts me is that I firmly expect that society as we know it will entirely collapse before this technology can really be capitalized. It's not a very comforting expectation, but it somehow bothers me less than the idea of techno-fascist corporate feudal states taking control of everyone's thoughts.
Maybe they can do a resolution of inquiry as a first step, demanding the executive branch provide the document to congress.