Tag Archives: PTSD

Amazing Memories and the Potential Future of Memory Research.

memory

Imagine being able to remember everything you have ever said or done. If you’re like me, I barely remember what I said two days ago let alone everything I’ve ever said. Though, I’m sure it would get rather annoying to our partners if that were the case. There are those rare individuals who have a gift (or curse) which is called “Highly Superior Autobiographical Memory” or HSAM for short. These individuals have the uncanny ability to remember more personal and emotional memories. Memories referred to as episodic memories.

Episodic memories are just that, memories that have personal meaning that are tied to emotion. The other type of memory is called semantic memory. Semantic memories are not tied to emotions, they’re just facts. So if I ask you, who was the first President of the United States? Or, what is the capital of the United Kingdom? There probably is not much if any emotional ties to these answer, yet you were able to remember them. This is your semantic memory. Don’t worry, there are semantic memory champions as well:

So, it seems as though you can’t have it both ways, but that you can at least practice really hard and become good at your semantic memory. But how does memory really work? There are two ways that we’ll talk about it, the first will be cognitive and the other will be more neuroscience.

Cognitive psychologist use the Modal Model of Memory, which follows a path from sensory input, to sensory memory, to working memory, and then into long-term memory (LTM). Working memory is sometimes referred to as “short-term memory” though that term is not used as much anymore. From working memory, it has three places to go, the memory can decay, it can move into long-term, or the individual has to keep the memory active through rehearsal. Working memory has a capacity though, it can hold 7 items (plus or minus 2) within. It also has a time limit which is roughly 30 seconds, though if you believe old Hollywood movies, it’s more like 5 minutes. Once the memory goes into LTM, cognitive psychology doesn’t go into how it is stored, just mainly into how it is retrieved. For this, we turn to a more neuroscience approach:

According to Neuroscientists, forming a LTM starts this chain of neurons connecting that otherwise don’t normally connect. The example used above is building a bridge between two areas that weren’t previously connected. So, let’s take the example of the rats, when the tone is played, they receive a shock. After the first time, neurons are being connected to tell the rat, this tone equals a shock. After it is done a few more times, the connection between the neurons is stronger (long-term potentiation) and the signal is able to travel quicker when recalled.

This is only at the cellular level and does not fully explain the entire purposes, but it goes far enough for our purposes in this post because there has been a study done recently that challenges this school of thought. Neuroscientists have recently found that memories may actually exists within the neurons themselves. The implications of this, if supported, has not only the potential of changing the way in which we think about memory, but it could mean hope for those suffering from illnesses like PTSD and Alzheimer’s.

For PTSD sufferers, this could potentially mean that we could do a “Sunshine of the Spotless Mind” and zap the neurons and get rid of the memories in which the individuals are having the problems with. For Alzheimer’s, this could mean that their memories are truly lost and that they could, with further research, regain some of the previously thought lost memories. The research is really still new and definitely needs further testing to gain any sort of support and I remain skeptical as one critic suggested that the “results were observed in the first 48 hours after treatment, a time when consolidation is still sensitive.” Consolidation refers to the process in which working short-term memory becomes long-term memories.

As this is the last post that I’ll probably be making on this blog, I leave you with this scene of Eternal Sunshine of the spotless Mind:

Fuhgeddaboudit

We all have memories that we would prefer to not remember or have memories of moments that had been forgotten happened until something triggered that memory to be conscious.  But what causes this to happen?  We could take PTSD for example, a fine case where memories that are so vivid and sensory driven, just as easily manifested, be so actively forgotten? Like we learned in class, the brain takes in sensory information that we don’t always pay attention to.  We may engage in experiences that encourage the retention of the memory but just as actively as the mind can take in information, it can also ignore information.  Giving rise to the theory that the brain has multiple processes that go into memory, both long term and short term. I wanted to know (a) if these cues that we use in our everyday lives to help us recollect memories, have the same function in a suppressed memory, (b) what happens in the brain when memories are repressed, and (c) what happens to these memories when they surface after being repressed?

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(a) One study done on children and adults to show that the brain has the ability to actively suppress information/memories to limit unwanted material in their consciousness.  This is caused by the part of the brain increasing in activation (lateral PFC, in charge of short term and working memory) and had reduced activity of memory-related structures (Medial TL) including the hippocampus, the part of the brain that runs much of the translation for long term memory.  This results in less declarative memories, one type of long term memory that contains facts and events that help recall (or “declare”) memories.   This also shows that the brain has active control over memory processes, specifically declarative long term memory along with filtering and a number of processes.

(b) Another experiment was done where they had participants who were asked to memorize a list of word-picture pairs and were asked recall each pair and their brain function was recorded.  After, they were told to do a similar process except this time they were to not think of the picture that corresponded with the word.  A fMRI scan was done on each subject to monitor brain activity.  They found that the brain had an especially hard time suppressing the older pictures learned versus the newer set of pictures they were shown.  This showed psychologist that visual memory in long term memory was harder to repress than working/ short term memory.  They also found that over time, it was easier and easier for the subject to repress the visual memory of the word, i.e. higher subliminal priming.

The cognitive approach that was in the articles I read were what parts of the brain were used and what memory processes were inhibited in the active suppression period.  So far, the studies have shown that long term memory is still intact with the memories but is stored differently, hinting to maybe a different encoding system or connections as discussed in class.  We know that the brain has different stages of memory and different types of memory.  We also learned that certain memories have connections that help with quicker, better long term processing after being presented with a cue.

memory-block-628x300(c) But what happens to these old repressed memories that surface after years of repression? Studies have shown that a number of things can happen to these memories.  In the case of trauma, like PTSD and abuse victims, even more variations were seen.  Memories that are being repressed, especially those that follow trauma are extremely malleable.  They had been seen to increase in intensity to the complete “termination” of the memory (seen mainly in children of a young age).

Psychoanalysis and cognitive psychologist have been working hand in hand on more studies that ask questions like where did the memory go?  What mental processes keep the memories suppressed and are these processes that allow these memories to seep through when memories surface if they ever do?  I was interested in these articles because we talked about memory in class and I wondered how Brian Williams could just “make up” a memory and I found these articles that talked about the opposite, not making up memories but forgetting them.  I hope to find more articles in this topic to further my understanding on memory suppression and its cognitive processes.

http://psychcentral.com/news/2014/03/19/suppression-of-memories-can-be-beneficial/67312.html

Chronic stress and memory loss

When it comes to memory loss we often think of diseases like Alzheimer’s or traumatic brain injuries. As college students, we don’t think of the reasons as to why we forget our books in our cars or why that assignment slipped out minds. We simply put it to being absent minded or the fact that we have other things going on that distract us.  Stress isn’t the first thing that comes to mind when as a reason we forget things. However a recent study done in 2010 suggests that it may be the cause.

The study, A critical review of chronic stress effects on spatial learning and memory by Cheryl Conrad suggests that chronic stress vs. acute or high-levels of stress actually reduce spatial memory.  We have been learning recently about spatial memory, which is in charge of being familiar with our environment. We need our spatial memory to find our way around campus, We also need it for our spatial working memory to temporarily keep information while we take a test or work on an assignment. These qualities are extremely important in the daily lives of college students.

Researchers at the University of Iowa found the connection between the hormone found in stress-cortisol and short-term memory with rats. The amount of cortisol reduced the number of synaptic connections made in the pre-frontal cortex reducing the success of short-term memory.

There is a difference between long-term memory and stress. If the stress is acute or high such as experiencing an earthquake or getting into a car accident, your memory is actually improved and the ability to recall these events are easier because they are stored in the area responsible for survival. Low levels of chronic stress or anxiety can alter the brain and cause damage to memory. White matter in the brain is increases with stress, this is good for sending signals such as messages across the brain but reduces neurons that are in charge of information processing. This is shown in research on PTSD patients with increased white matter and long-term stress.

Researchers at Berkley suggest that the effects of long-term stress and anxiety in the younger generation may be the cause for mood disorders, learning disabilities and anxiety. From this I think we can all take the suggestions to reduce stress in our lives and manage a healthy balance. Anything from saying no to an extra meeting here and there or going for a walk on a nice day to get out of the office. We all need to practice self-care so we can take care of our memories in the long run.

http://www.cnn.com/2014/06/17/health/memory-stress-link/