It’s interesting that humans can fly to the moon and reach the depths of the ocean but still don’t understand how their own memories work! Memory is a strange conglomeration of physical, chemical, and psychological aspects, and scientists still aren’t sure how memories get stored in the long term memory.
Your long term memory can last anywhere from a few days to decades. In fact, anything you remember for more than about thirty minutes has been at least temporarily stored in your long term memory, since your short term memory only lasts about half an hour, according to most theories.
But how do memories get put in long term storage? How do you keep them there longer and in better detail? How do you recall memories later on? These are still questions we’re trying to answer!
Biochemistry and Long Term Memory
One new finding from the Duke University Medical Center is that long term memory storage is both a physical and a biochemical process. We’ve known for a while now that memories are related to synapses in the brain. Your synapses develop rapidly in early childhood and can continue to move and form all the way through your life. Synapses, in the plainest possible terms, represent links between information in your brain.
The study at Duke showed that certain molecules that usually travel between synapses in a matter of seconds can actually make a signal that lasts for a much longer time. It seems that longer lasting neurochemical signals create longer, stronger memories! We’re still not really sure how or why this works, but we do know that people with memory problems often have abnormal signals coming from those same neurochemicals.
Types of Long Term Memory
One type of long term memory that starts forming without your even knowing it is implicit or procedural memory. These memories help you use a pencil or drive a car. You don’t have to actually recall these memories explicitly to draw on them.
Another type of memory is explicit or declarative, which is a memory that you have to consciously access. For instance, you have episodic memories, which are about certain events in time, and semantic memories, which are things you know about the world, such as customs in your country, or how to get to your house from the grocery store.
These are all part of your long term memory, and they aren’t the only categorizations, either. Others include emotional memories, which evoke strong emotional responses, and prospective memory, which helps you remember to get to your doctor’s appointment at a certain time or do the laundry on a certain day.
Long Term Memory Problems
It’s not uncommon to have basic, everyday problems of forgetfulness. Where did you leave your keys? What was the name of that restaurant someone recommended? It’s right on the top of your tongue! When these problems occur, your neurons are usually firing, trying to pull up the memory, but the receptors aren’t connecting for you.
Of course, brain injuries and neurodegenerative diseases like Huntington’s Disease and Alzheimer’s can cause long term memory problems. These problems may target certain types or categories of memories, depending on which parts of the brain they affect.
This is one of the most interesting things about memory that we still aren’t sure of yet – which parts of the brain are associated with which types of memories. A stroke patient, for instance, may forget things that happened in the past ten years but remember things well before that, or he may forget how to use a pencil but remember how to play a guitar.
Long term memory is certainly an interesting part of being human. Some argue, in fact, that such memory and recall is what makes us human! Improving your long term memory may lead to better memory recall and less risk of memory loss with aging.