Short vs Long Term Memory Storage

Some comments in this thread got me thinking about long-term and short-term memory storage and the transfer of one to the other.

My brief history.

My senior year in college (1989) I played intramural flag football. We had a game scheduled for 6PM. I can remember clearly 2PM that afternoon as I remember deciding (in my empty-headed way) to skip my 2PM History of Britain class.

That’s the last thing I remember for that day. Literally.

I’m told I got an elbow to the head about 6:15PM or so. It banged me up but did not knock me out. I’m told I could still function and in fact played the rest of the game. One of my pals checked up on me by asking me what the baseball standings were and when I expressed disbelief that the Cubs were in first place in September (I’m an avid fan) he took me to the local hospital.

I have two or three hazy memories of being in the hospital. They’re fuzzy (literally) and in black and white.

The first clear memory I have is waking up in a hospital bed about 9AM the next morning.

I can understand losing memory after the trauma has been received. That’s all well and good. Brain damaged. Needs to heal.

But those earlier 4+ hours intrigue me. It’s more than 13 years down the road and those memories appear to be gone forever. Somewhere in the transfer of short-term to long-term storage something got wiped (or made permanently inaccessible).

I’m also told that during my time in the hospital I couldn’t remember anything for more than a few seconds. I would be talking to person X, turn away for a few seconds, turn back to person X and ask them “When did you get here?”. Repeatedly. And for all persons.

I’m told it was a trial to be with me. Though my kid sister says it was hilarious.

So what’s the mechanism there? How does memory got from short-term to long-term?

It’s not really very well understood right now.

One theory is on something making it from short-term to long-term memory is the way it gets “encoded”, for lack of a better term.

If you want to learn (or as it applies in this case, remember) something, one of the best things you can do to help yourself remember it is to associate it with something else. What does this point, argument, theory, etc. have in common with this similar point? What differences do they have? How does it relate to something you already know? If it’s a complex bit of information, is there a mnemonic device or some other memory aid you can use to help you remember it?

As the theory goes, the more you associate something with other things, the more connections you form with it to other information, thus making it easier to recall later.

When students cram for tests, they rush to fill their minds with as much information as they possibly can, in a limited amount of time. In doing so, they fail to properly store the information in their minds, and, more importantly, they fail to make the information easily retrievable. This might be the reason that cramming usually leads to unsatisfactory performance on tests.

In your case, I think the reason you remember 2PM that day even though it happened 14 years ago is because something significant that day-- you got knocked on the head and went to the hospital. Maybe it’s something similar to the theoretical “flashbulb memory” (where people can recall with great detail what they were doing when something striking or significant happened, such as JFK’s assasination or the WTC attack). Why you can’t remember what happened in the 4 hours between them is anyone’s guess. Maybe your head injury played a part. I hear it’s common for head injury patients to not remember the minutes prior to whatever it was that caused their injuries. Or maybe you did something so mundane and routine that it’s become indistinguishable from the times you did it before then, or since.

Just think, if you’d only been able to improvise a ballpoint pen tattoo you could still be chasing the owner of that elbow today.

My brother was involved in a serious bicycle accident a few years back, ended up going over his handlebars at a high rate of speed and hitting the ground hard enough that people half a block away came out of their houses to see what the noise was (thank the Gods he was wearing a helmet!). I believe he was knocked unconscious by the fall; what I know for sure is that when the paramedics arrived and questioned him, he didn’t know his own name. They found his checkbook in his backpack and that’s how they were able to contact my parents (he lived at home at the time).

He remembers events up to an hour or so before the accident; he vagely remembers leaving work that night (he was biking home from work when it happened) but after that the next thing he remembers was “coming to” in the hospital much later. The memories before and after the blow to the head are still gone. So, whatever exactly causes that phenomenon, it seems to be common to certain kinds of head injuries.

Apparently so. Stranger and stranger.

AudreyK, thanks for the info but I’m not sure that this part:

…applies since I’ve never been able to remember those hours. The next day they were gone and they’re gone even still. So I don’t think it’s an lack of associative memories that make that stretch of time impossible to recall.

The hypothalmus which lies in the top center of the brain joins the two major halfs of the cerebrum. Awake or asleep the hypothalmus is easily the busiest place in the brain.
My own feeling based on various studies and cat scan results is that the hypothalmus is at least in part analogous to RAM memory in a computer and the cerebrum is more like the hard drive/long term storage medium.
As you absorb what happens throughout the day the hypothalmus stores everything you see, hear, taste, etc… But the business of transerring these memories/events to permanent storage involves cross referrencing the new information with the old and probably also throwing out the redundant. Most of this occurs during sleep although important events or say a phone number can be remembered if concentrated on (meaning sent to permanent storage purposefully).
Likely in your situation you were not completly “conscious” and the images and input you were recieving were not being properly processed by your brain and were simply “deleted” as so much nonsense. Just as a dream is primarily nonsense in most cases probably aring from the “crossreferencing” that is going on in your brain as you sleep.
I believe also that the thalamus generally gets “full” when too much information is recieved or long periods elapse without allowing the brain to sleep and perform its basic housekeeping chores.
This would explain memory loss and confusion that happens to sleep deprived individuals. It is also why it is considered a good idea to “sleep on” a problem. Associations that you may not have been able to make with a new piece of information may find those associations are made while asleep.

The phenomenon of events immediately prior to brain injury being lost is called anterograde amnesia - the inability to form new memories. Loss of existing long-term memories is called retrograde amnsesia.

In really rough terms, your brain has three primary forms of memory. “Scratch pad” memory is an itty-bitty area that handles the here and now. Everything enters through here. It’s where a phone number is stored between being seen on paper by your eyes and buttons being pressed by fingers, that you just put three cans of soup in your shopping cart, a blue truck just drove by, a girl wearing a yellow jacket walked past you and went into McDonald’s and things like that. Memories only last a couple hours here.

From scratch pad, memories are sorted. If it’s something important, it’s moved to short-term for further review. The nonsense “static” is dumped - in this case, you probably forget about that truck and the girl, unless she’s your girlfriend.

Short-term is where you’re hanging on to “A loaf of bread, gallon of milk, tomatos and maybe they’ve got pork chops on sale” as you’re on the way to the grocery store, and hopefully, the things your professor explained make their way this far.

Long-term is just that. Essentially permanent, it’s where your brain’s keeping your mother’s name, your name, where you live, the combination to your locker, 5x7=35, and such.

Moving stuff from one area to the next isn’t instantaneous, and as described above, it’s believed that a lot of long-term storage is cataloged and set up when we sleep.

When you got that whack to the head, all processing stopped for a while as your brain was essentially re-booting itself, so the couple hours’ of stuff in scratch pad was simply lost.

Physical trauma isn’t the only thing to affect memory. A few years ago, I had been prescribed Halcion for insomnia. In addition to making you sleep, it’s since been discovered that Halcion disrupts scratch pad and short term memory and causes anterograde amnesia. As a result, I’m missing about a year’s worth of memories as they were never fully recorded and processed. To this day, the effect continues - it’s as if a hypothetical 10% of my scratch pad “slots” are damaged so anything that lands on them is garbled or simply lost. :mad:

I’m afraid you have it backwards, gotpasswords. The OP’s inability to remember anything between 2:00 and his injury is retrograde amnesia. These events aren’t new memories; they already happened. His inability to form new memories after the injury (as when he kept repeating his questions) is anteriograde amnesia.

So I suffered from both, apparently due to a blow to the head.

Follow up question, then.

Is it truly missing information or is it just an access issue?

My meaning was that in your case, I don’t think it’s an issue of short term/long term memory, or encoding or retrieval. I think you remember part of that day because something noteworthy happened, but I think your memory is incomplete because of that same noteworthy thing: your head injury.

I have pretty bad short term memory loss [due to depression I believe], I cna eventually remember things, but weeks and weeks after the fact usuall. A friend said "when I bought … " and I said that had to have been more than 6 months ago cuz I can remember her buying it!