aftersensation vs memory image

aftersensation and memory image both are nouns.

Word	Noun	Adjective	Verb	Adverb
aftersensation	Yes	No	No	No
memory image	Yes	No	No	No

As nouns, memory image is a hypernym of aftersensation; that is, memory image is a word with a broader meaning than aftersensation:

aftersensation: an image (usually a negative image) that persists after stimulation has ceased
memory image: a mental image of something previously experienced

aftersensation (noun)	memory image (noun)
an image (usually a negative image) that persists after stimulation has ceased	a mental image of something previously experienced