In /Interface/ (https://www.goodreads.com/book/show/6563920-interface), they imagine kind of the opposite of this: They have a primitive mind-machine interface and probe all the different kinds of sensations it can transmit to a person's mind --the smell of apple pie is one example--and train them to associate it with some meaning (in this example, the guy is a politician and associates apple pie with "American values"). Then the campaign manager can press the "apple pie" button, which causes the politician to smell apple pie, indicating that he should should transition to talking about "American values" in his speech.