Partly true. Unconscious is when you are unable to
consciously respond to your environment. Unconsciousness is not necessarily Coma. The subconscious, depending on the type or level of unconsciousness, may still respond to stimuli.There are layers of unconsciousness. Sleep is a type of unconsciousness. Coma is a form of unconsciousness. (Actually, there are varying forms/layers of coma also.) Not all unconsciousness is coma.D&D's rules don't say if sleep is or isn't included in the Unconscious Condition. D&D's rules do not imply or define that the Unconscious Condition is the same as Coma.D&D's rules do not have that level of granularity. That's what DM's are for.It is consistent with D&D's rules for a DM to allow a sleeping character to make a perception check. It is just as consistent for a DM to rule that a sleeping character is not allowed to make a perception check.It is consistent with D&D's rules for a DM to allow shaking, slapping, or cold water to revive (or attempt to revive) an unconscious character. It is just as consistent for a DM to not allow this.It is consistent with D&D's rules for a class to have a mechanic that triggers a recovery from the Unconscious Condition; even one that uses Inspiration as an Emotional trigger to do so - especially as rules-wise, specific trumps general.Such emotional triggers are also consistent with some real-life examples. (For example:
Mother_awakens_from_coma_after_hearing_newborn_baby's_cries. )Not entirely true, and also depends on what your definition of "response" is. An unconscious person may not awaken, but MRI and other sensory data has shown that some unconscious people (depending on the level and type of unconsciousness) can and do respond to loud noises and other external stimuli. This shows that hearing and other senses still work and that the subconscious brain is still processing them (again, limited by the level or type of unconsciousness). There however is no "Conscious" response - at least not until consciousness is restored. Subconscious responses may stimulate the sympathetic nervous system to an extent that a return to consciousness is triggered.