Italian city, on the contrary, pervaded my recollection (6)
I believe the answer is:
memory
'recollection' is the definition.
(I've seen this in another clue)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for memory that I've seen before include "Mental faculty; PC chip" , "Something recalled; part of computer" , "The ability to store things in mind, and to recall (6)" , "Power of recall" , "reminiscences" .)