Subfield of memetics that deals with the dynamics of memes inside a single mind. Memes compete with other memes inside minds. Intracranial memetics studies these dynamics - and other forces on memes while they are inside minds.
Note that intracranial memetics also deals with protomemes failed+memes and other ideas that may never go on to become memes. See also intercranial memetics.
Tim Tyler has more details. http://on-memetics.blogspot.com/2011/05/intracranial-memetics-and-intercranial.html