Sunday, October 04, 2009

Emotion and Memory

My friend got lost years ago while on a cross-country skiing trip. The morning paper and the evening news reported search efforts in daily, discouraging detail. Time passed, and the possibility that my friend and her skiing partners lived on became less and less likely. One day, however, while driving home with the car radio on, a breaking-news bulletin announced that they had been found, alive and well if a bit frost-nipped on fingers and toes. I had to pull over and get a grip on my teary emotions.

I can tell you the exact spot I pulled over, the weather, and where I had been. This all quite remarkable as, on average, I've a big picture sort of mind while the details leak before storage in long-term brain files (no surprise this to my husband). My friend later told me that everyone invariably related the minutiae of the moment in which they'd heard of her rescue--this after I'd supplied her with my experience as if it were the most fascinating tale.

So what's with this emotional boost to memory? If you were alive at the time, you can doubtless remember where you were when Kennedy was shot or the moon landing occurred. Likewise for the World Trade Center tragedy and perhaps Princess Diana's death.

Japanese neuroscientists studied emotion and memory in patients with Alzheimer's Disease (AD) following the devastating Kobe earthquake of 1995.(1) They performed brain MRIs on all the subjects, then checked out who remembered the earthquake and who remembered the MRI. The patients were much more likely to remember the quake, suggesting that intense emotions reinforced the memory.

The researchers went on to correlate the ability to remember the temblor with the residual size of the subjects' hippocampus (the brain's memory center) and amygdala (emotional center). Victims of AD are known to suffer from brain shrinkage. Those who retained the emotional memory of waking up to a significant earthquake were much more likely to have a normal-sized amygdala no matter the size of their hippocampus, and, likewise, those with impaired emotional event memory had more intense amygdalar damage.
1)Kazui, H. Emotion and memory. Four studies of the emotional memory in Alzheimer's disease. Japanese Journal of Neuropsychology. VOL.18;NO.3;PAGE.150-156(2002).


JeanMac said...

This is surely true for Wayne - he remembers the very good or very bad.

Cilicious said...

I wonder if it is the same thing with memory and smell.
Certain smells take me right back to a particular place and time.

Mauigirl said...

Interesting - makes sense. And Cilicious, I'm sure you're right, that smell is another of those things that help people remember. (Think of Proust and his madeleine...) I think they've even done some studies that showed people remembered information better while being exposed to some scent, I forget if it was chocolate or vanilla.

Anonymous said...

What seems to be overlooked a lot is the role hormones play in all this.. memory, smell, etc..etc...
Some doctors are specializing in hormones now, and relate it to everything about us....there is a one can join , too. Includes discussion on environmental hormones.
I recently saw a new take on AD, and I cant remember what it said, ha...
Seems like you have uped the info lately, thanks