Every time we think a thought, make a movement, experience something, this is transformed into electro-chemical energy which is then stored in the brain. We create pathways that allow the energy to travel in a similar fashion each time it is triggered. The more it is triggered, the easier it is for the energy to go that route. This is how habits and behavior, both good and bad, are created.
A suggestion that is made to counter the effect of previous suggestions that have been given to a subject. Neutralization is especially important in stage work.