The irritable substance does not forget.
'In 1904, Richard Semon (7) proposed the idea of the “engram” and defined it as “the enduring though primary latent modification in the irritable substance produced by a stimulus (from an experience).”
https://www.jbc.org/article/S0021-9258(22)00306-4/fulltext#.Y7GgPgqpdhA.twitter