There is some doubt that our CNS including the brain parts are necessary to consciousness. It is an old question. Some creatures exhibit clear responsiveness and behavior with no hint of a nervous system at all, even our cousins the plants do that.
At the moment we don't know where the seat of consciousness resides, but I'd bet it's in at least one cell located near the main signal switching unit in the brain.
Now a thought like that is a tad heretical since it denies primacy to the brain ~ on the other hand it allows for consideration of all cellular life as repositories for fully conscious (if not knowledgeable) entitites ~
Nikko Tinbergen suggested that 100% of all the known functions of a human being can be found in the single celled paramecium. Lorenz, his contemporary, also discussed King Solomon's Ring, a kind of an icebreaker in any conversation about freewill, consciousness, and just exactly why is that parrot trying to make time with my girl.
Think of multicellular life as a prosthesis for a horribly handicapped, but fantastically intelligent, microscopic lifeform.