Earworms as memory triggers?

Is anyone else's earworm kind of an asshole? After having the intro to a particular Grateful Dead song (not going to name it for fear of it making a repeat performance) on repeat for nearly a week, I started to think about how certain songs can come to be tied to very specific memories, complete with all sensory recall.

This particular song was the set 2 opener the last time they ever played Seattle, and I was there so it conjures up some very specific memories for me. Everything from the smell of pot smoke (no, before you ask, I don't) to what I was wearing to the late day light playing off the trees that surround the venue (Memorial Stadium) — it's all connected in my brain. I can't hear the song without seeing the sights and smelling the smells.

The other powerful example from my own life is the song "I Want To Know What Love Is" by Foreigner. I don't like this song, at all, but it will forever be connected in my brain to ski lessons when I was 7. There was only one radio station that came in all the way to the local ski area, so that's what we listened to in our '82 Honda to and from lessons. I hear the song, and I recall the way the heat felt hitting my face when I adjusted the registers on the dashboard. I smell the hot cocoa my mom got me from the lodge after lessons. And I see the steam rise from my warm self after finishing up for the day. I even remember how the strange, almost Corduroy-like fabric felt against my face as I dozed off on the way home.

Give me a second and I can come up with at least half-dozen other examples from my youth and youth-ish times.

But why?

Why do songs connect so strongly with memories? And why, for the sake of your deity of choice, do I remember the seat fabric of my mom's '82 Honda?!

So I did what I do. I read. A LOT. And what I found out is absolutely fascinating. Well, to me and any of you out there who geek out over neurological anomalies and psychological weirdness the way I do.

This is going to be a brief version of the 10,000 ft view on this topic, mostly because I'm far too knackered to even hope to form that many coherent sentences tonight. It turns out that the brain region responsible for retrieving autobiographical memories (not where they're kept, mind you, just the part that retrieves them from long-term storage) is the same area where we process tonal shifts. For you neuro-nerds it's the dorsal region of the medial prefrontal cortex, right behind your forehead. It also happens to be the latest region to develop after we evolved into Homo sapiens.

Since things like songs are stored primarily as tonal shifts, the whole "ear worm jogs loose a memory" scenario is starting to make more sense.

Music triggers many other regions of the brain as well, of course. Centers of motor activity/control, emotional regulation, and creativity light up like a Christmas tree, especially for those songs that resonate strongly. But here's the part I find truly fascinating — the prefrontal cortex area lights up just as strongly, if not more so, than the others when it comes to songs we associate with memories.

But which way does it go? Do more salient memories trigger stronger associations with songs? Or to songs we love trigger stronger associations with memories of when we first heard them?

Turns out the scientists doing this research don't know. Yet. The focus of their work is actually on developing possible treatments for Alzheimer's patients, since the prefrontal cortex is one of the last areas affected by this degenerative condition. At the moment, all they can say for sure is that the connection is real and they can point to it on fMRI scans. The rest is open to interpretation.

For now, the fact that songs and memories can strengthen the same areas of the brain is enough for me. Now if I could only get this song out of my head...