I don't mean understandable reactions and associations - like being robbed by a guy in a hoodie and thereafter fearing anyone wearing a hoodie even if they're a 90 year old nun. I mean utterly disconnected pieces of random brain-data.
For instance, every time my brain hears the first five seconds of Ebeneezer Goode, (which is what tween girls of my generation listened to, Justin Beiber not having been invented yet) I irresistibly see Patrick Troughton's Doctor Who in a fur coat.
I used to think this was just because I was odd, but it seems it could be an Aspie thing. In an old article which I now can't find online, Tito Mukhopadhyay described how as a child the concepts of clouds and bananas became fused for him in a similar way. I can't remember exactly how they came together - perhaps someone said "banana" while he was looking at a cloud, or said "cloud" while he was eating a banana - but after that, the two ideas were muddled together in his mind.