When Memory Has a Mind of It's Own

Our understanding of memory is one of the things that make us intrinsically human. Many organisms have memory processes, they learn, they adapt o their surroundings, but humans have the ability to change those functions, to control them. We can choose what we learn and what we don't, we can memorize information and in certain cases force ourselves to omit things from our memory. Our lives are completely based around this function - adults work in a job doing things they have learned to do, children learn in school about things from our past, stories of our past are passed down from generation to generation by memories. Even the basic processes of our bodies utilize systems that have their own type of memory - our bodies, even down to the smallest molecules, "know" what their purpose is (2). This stasis enables us to function at the high level that we do - all parts of the body working together to produce a living, breathing, functioning, and above all remembering organism. Our memory grounds each and every one of us, makes us unique. Every person has different experiences that make their self. It seems that in this sense our selves are dictated by what surrounds us, what inputs come in and how those inputs are automatically dealt with. The problem, it seems, is when the reality of memory can be altered, when memory seems to have a mind of its own.

On a basic level, the biology of memory begins with three separate processes. The first process, encoding, deals with the processing of visual, acoustic, and semantic inputs. Second, in the storage process, the brain takes this information and creates permanent or semi-permanent records of the encoded inputs. This is called the consolidation process and occurs when inputs are received and connections in the brain between neurons, called synapses, are strengthened. The final process, retrieval, refers to the process by which an organism can recall these stored memories either consciously or subconsciously when needed. In addition, there are two different of memory: short term and long term. Short-term memory occurs immediately after the input signals are received. These signals are stored only temporary in the hippocampus, and there for this type of information can only be stored for a short amount of time (7,1). The hippocampus then consolidates certain memories into long-term memories through a process called long-term potentiation (2). However, long-term memories are not stored in the hippocampus but in various parts of the brain depending on exactly what type of memory it is (7,2). Generally speaking there are two types of long-term memories that the brain deals with: explicit and implicit. An explicit memory involves a conscious recollection of a specific event at a specific point and place in time, and knowing that we know these things. Implicit memory deals with unconscious processes, such as learning or subtle details in experiences that you do not pick up on consciously (2).

But it is not always this simple: when memory mixes with fear the boundaries of control and reality blur. The memory consolidation process can be enhanced or limited by many factors. When the body is undergoing a stress reaction, hormones such as epinephrines, adrenaline, are released into the body which trigger the release of more stress hormones, also stimulating the amygdala which has access to many of the parts of the brain that facilitate memory (6). Fear instigates this stress reaction very well. When a person has a strong fear memory, it is usually hard to overcome that fear because it is so strongly engrained in the mind, especially if the incident occurred at childhood when the brain is still developing. The fear response itself is a neural pathway where visual inputs are transmitted through the thalamus and amygdala which allow the brain to make immediate "fight or flight" responses to the situation, and then other, more long-lasting inputs are being sent from the visual cortex to other parts of the brain that analyze, interpret, and store the information that is coming in (5). The brain is linking the sensory and auditory systems to the autonomic nervous system without any conscious knowledge. The brain is controlling how a person remembers something, and therefore controls their reality, all without the participation of the I-function.

Interestingly enough, this idea of extreme memory enhancement when pushed to the extreme can have the exact opposite effect: the brain actually represses memories. As mentioned before, when the brain processes experiences it creates both implicit and explicit memories. In cases with extreme emotional input, such as sexual abuse in children, some researchers believe that the brain can actually repress the ability to form explicit memories in an act of self-preservation in a dangerous environment (2). However, this does not include implicit memory - the mind can still process an experience and store it in long-term potentiation without the knowledge of the I-function. However, these memories are not completely behind locked doors. Since implicit memory often deals with sensory details of situations that the conscious mind passes over, exposure to any of these same inputs can cause such repressed memories to be restored into the explicit memory. For example, in a case of a person who repressed memory about being abused as a child, the memory returned years later when a friend jokingly placed their hands around the person's neck, immediately reinstating the memory of the long forgotten incident (4). This issue is under extreme debate and has come to be a large problem in recent decades is sexual harassment cases. Once the topic of repressed memories began being studies and treated as a legitimate form of testimony, similar cases being springing up all over the place. When people knew realized that perhaps they too could have long repressed memories, the problem arose that more and more people began tricking themselves into believing they had had an experience, repressed it, and then rediscovered it (4). If you believe something strongly enough, a memory can go from explicit to implicit and seem as real as any real memory one has. Neurologically, such a false memory and a genuine memory may look exactly the same at the neural level, so where is the distinction? Where is the line between reality and falsity?

When questioning who has control of our memory, the initial response is simple: we do. Our brains are our brains and we control them. If only it were so easy. As you delve further and further into the intricacies of memory, it gets more difficult to separate exactly what is making the executive decisions. An individual can control their explicit memories, but have no control of their implicit memories. They could control perhaps certain emotions they experience, but they cannot control any that are tied to autonomic nervous system responses. Once a memory has been consolidated, the brain has the ability to repress it, retrieve it, switch it from being implicit to explicit, or even create a memory that never existed. If nine different people are in a single room and frightened with a venomous snake, one can guarantee that they will all have completely unique experiences: one may have no fear response, one may have a fear response and create a stronger memory of the scene, one may be so traumatized that the memory is immediately repressed. Whose experience is more real? Who is experiencing the ultimate reality of the snake? What is controlling all of these unique responses? It seems that the brain is hardwired to do these things for us, without giving any clue to the I-function. The self is determined by forces it can't consciously control. Our memory has a mind of its own.

WWW Sources
1) http://www.sciencedaily.com/releases/2005/09/050916074554.htm; "Researchers Identify Where Emotional Fear Memory and Pain Become Permanently Etched in the Brain," Science Daily.
2) http://psychologytoday.com/articles/pto-19950101-000021.html; "It's Magical, It's Malleable, It's ... Memory," Psychology Today.
3) http://www.kspope.com/memory/memory.php; "Memory, Abuse, and Science: Questioning Claims about the False Memory Syndrome Epidemic," Memory and Abuse.
4) http://discovermagazine.com/1994/may/flightsofmemory374; "Flights of Memory," Discover.
5) http://www.sciam.com/article.cfm?articleID=000C8E0E-8BFB-136B-8BFB83414B7FFE9F&sc=I100322; "Can We Cure Fear?" Scientific American Mind.
6) http://www.sciam.com/article.cfm?articleID=0001E30A-C0EA-136B-80EA83414B7F0000&sc=I100322; "Erasing Memories," Scientific American Mind.
7) http://en.wikipedia.org/wiki/Memory; "Memory," Wikipedia.