concern vs negative stimulus

concern and negative stimulus both are nouns.

Word	Noun	Adjective	Verb	Adverb
concern	Yes	No	Yes	No
negative stimulus	Yes	No	No	No

As nouns, negative stimulus is a hypernym of concern; that is, negative stimulus is a word with a broader meaning than concern:

concern (noun)	negative stimulus (noun)
something that interests you because it is important or affects you	a stimulus with undesirable consequences
something or someone that causes anxiety; a source of unhappiness
a feeling of sympathy for someone or something
an anxious feeling
a commercial or industrial enterprise and the people who constitute it

concern (verb)	negative stimulus (verb)
be relevant to
be on the mind of