In some ways, consciousness is the only thing we can be sure really exists. Our subjective ability to experience things lies at the core of what we would consider the self. Even if the world is really a simulation, your ability to be aware of it and experience it is something you can be sure of.
University of Wisconson, Madison researchers have found a kind of "consciousness switch" in a specific area of the brain. When they hit this spot with electrical stimulation, monkeys immediately woke up from an anesthetized state.