I'm no expert in neurology or any related field but I think the concept on consciousness is somewhat fuild but overall I would explain it like this:
Knowledge of self, aknowledging one's physical and mental limitations and one's ability to relate and interact with others and the environment in such a way that transcends on's initial limits if one is so inclined(ie, desire for growth and the choice not to do it).
Just responding to stimuli is not enough, because humans can accept that the stimuli and chose not to respond to it or can decide to act despite said inputs.
Confused: a definition is unrelated to what we 'want' consciousness to mean. I define it like this: we know what it is to be 'unconscious'. Conscious is the opposite of that, which is simply responsive to stimuli.
If we want to describe that other idea with a word, then perhaps self-aware is closer.
I can see you are trying for a 'working definition' of consciousness which would encapsulate the phenomenon without any philosophical wild goose chase involving defining essences. This approach has been wildly successful in science and mathematics, where many advances have been made simply by shedding intuitive preconceptions.
The problem with your tentative definition above is that defining consciousness simply as response to stimuli does not distinguish between a conscious response, and a mechanical response. These are at least notionally distinct, and it is very hard to regard then as being the same thing.
Knowledge of self, aknowledging one's physical and mental limitations and one's ability to relate and interact with others and the environment in such a way that transcends on's initial limits if one is so inclined(ie, desire for growth and the choice not to do it).
Just responding to stimuli is not enough, because humans can accept that the stimuli and chose not to respond to it or can decide to act despite said inputs.