Nostalgia

After my neuro exam, we went out to dinner and stopped at an international market along the way home.  Finally, I've found somewhere that can both sell me individual quail's eggs, as well as individually shrink wrapped Norwegian Mackerel.  If they're out of those, I can make do with canned pig tongue or box of dried goldfish from the snack aisle.  Aside from the unique and bizarre (to my occidocentric mind) the international market stocks a candy from my childhood, the Kinder-egg.  

My visit to the market made me aware of a fluke of neuroanatomy.  The olfactory portion of our brains involves, in part, the amygdala which is part of the limbic system.  The amydala, among other things, integrates incoming smells with visceral input, and mediates such reactions as salivation in response to a savory scent, or nausea in response to a foul odor.   Though closely related anatomically to the hippocampus, to my knowledge, the hippocampal and amygdaloid paths do not share any common, direct connection.  The hippocampus is thought to be involved with the creation and consolidation of new memories.  Though I don't know, I postulate that the lack of common connections is why we can't remember smells the same way recall visual information.   We can all picture our first apartment or picture what an airplane looks like without too much difficulty.  I doubt, however, that you can 'remember' what a lemon meringue pie actually smells like, in the same way you recall visual information, which would be by actually mentally 'smelling' the pie at the moment of recall.  We all know that sweaty feet stink, but upon reading this, you don't actually smell feet (unless they're your own) instead, we can only recognize a smell upon smelling it again.  At the international market, we purchased a box of Lu butter cookies as as post-exam treat.   Upon opening the box, I instantly recognized and pictured my childhood time in France when I must have eaten those very same cookies as a kindergarten child in Paris.   It's strange that you can't smell something upon recall, but that olfaction is still a very powerful component of memory.