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Saturday, August 18, 2012

Remembering to Forget: PTSD

The movie “Eternal Sunshine of aSpotless Mind” is essentially a morality play built around a common human desire to elevate painful memories by forgetting them. The movie ultimately finds its denouement by reuniting a couple who, through artificial precognition, have been exposed to the distressing memories of a relationship gone sour. Let's willing suspend our disbelief a bit longer and and attempt to separate the morality from the science. Would we still choose to forget? How could we forget? Ought it be modifying a memory, wiping a memory from the grey matter or cleansing a memory; which one is possible and which one would we choose? Bear in mind that every time we recall a memory it becomes tainted in comparison to the “pure” memory which was first implanted through experience. It follows in that logic, that people who suffer from amnesia retain the purist memories. Having no memories doesn't seem to be a valid alternative to unwanted memories. The inability to remember doesn't necessarily imply the total loss of memory. 

Oliver Sacks, the renowned neurologist, has shown that a man who was impaired by severe Alzheimer’s remembers little from his past and is, furthermore, is incapable of forming new memories. However, the man could recall with astounding accuracy the four individual parts of a whole host of songs he performed in his barbershop quartet. Two things are at play here. Firstly, it is the notion that portions of a memory are summoned from all parts of both hemispheres of the brain in order to make a new and unique recollection of a previous memory. In other words, the memory is altered each time we conjure up the scattered fragments, which, when pieced together again, is inevitably further from the “truth” of the initial memory. The second premise at play is tantamount to a persistent memory anchor. Regardless or despite brain trauma, which nullifies the construction of new memories or the ability to recollect vast swaths of old memories, there exists something innate in the brain which allows for highly particular memories to be recalled with vivid accuracy. Sacks sees this as a musical rudiment in the evolutionary hardwiring of the brain. He continues by stating that rhythm is the basal musical function which all humans have regardless of their shortfalls in more complex musical abilities like pitch and harmony. Taken even further, rhythm can be seen to be at the root of language which is our primary tool in group cohesion and social function. This is also evidenced in the Deaf who retain an inherent rhythmic tendency as witnessed by sign language communication which incorporates the same neural mechanics as spoken language. Steadfast memories garnered out of fear and trauma are the memories which we are most likely to want to forget in spite of how embedded they are in the human experience. Help may be just around the FDA approval corner. Scientists have discovered in the laboratory how these fear-eliciting and traumatic memories can be eroded away and possibly erased from our brains.

Here's how those scientists decoded the way in which trauma (i.e fear) works on memories and its subsequent erosion after the application of a particular chemical compound. During a two week period lab rats underwent intermittent acoustic stimulus followed by electroshocks (electrified metal floor in their cage) after the stimulus was introduced. The acoustic stimulus was introduced followed by a short delay after which the floor was provided a mild shock. The rats reacted to the stimulus by “freezing” in a catatonic state as they began to anticipate, in a Pavlovian behavioral way, the electroshock which was emanating from the floor. After the two weeks of applying the stimulus the rats were injected with Ibotenic acid in three areas of the brain; the lateral hypothalamic, midbrain grey region and the bed nucleus of the stria terminalis. Although the local neurons were slightly damaged the fibrous passageways were left intact. The next phase for the scientists was to test the hypothesis. The rats were now subjected to the same conditioning from the acoustic stimuli of the previous two weeks. Amazingly, the rats did not “freeze” during the interim between the noise and the shocks. The memory of the electroshocks had apparently been erased from the rat brain. It seems reasonable to conclude that fear responses can be eroded from the original memory. The study also concluded that introducing the Ibotenic acid immediately after a traumatic event could be a way to more effectively, and possibly permanently, erase fear-eliciting memory.

Again two lines of extrapolation can be pursued if this method is applied to the human brain. On the one hand, despite the introduction of the chemical which led to the eroding of memory as witnessed in the lab rat study, a residue of memory lingers. This might be because the social and cultural parameters engender a solidifying function which aids in retaining the core attributes of the memory. Rituals, trauma, collective mores and norms, which are all shared by a community and reinforced more frequently, allow for the memories to endure complete erosion. Furthermore, it follows the logic postulated by Sacks that the memories which withstand the erosion process or the reoccurring evolution of the memories each time they are recollected are the ones tied most closely to rhythm. Perhaps the person recalling the memory invokes a series of symbolic phenoms and those in turn are what assist the memory in retaining its core attributes. In other words, the rhythmic quality of language is the keystone for holding on to the purist possible memory. This shouldn't be a social or scientific bulwark to unlocking the full potential of erasing traumatic memories for those who wish to forget.

How can one qualify oneself to affectively forget? In order to modify a preexisting memory it seems that two components are needed: Ibotenic acid and fear-eliciting trauma. Applying the chemical will be supportive in altering the traumatic memories which are recalled. What if we were to manufacture this drug and dispense it whenever unpleasant memories popped up in our mind's eye? Bad day at the office: gone. The nagging morose feelings associated with a romantic break up: gone. A particularly unscrupulous event perpetrated by local, state or federal government: gone. That last one might be in the realm of pulp science fiction but in theory the applications for erasing memory are as limitless as the human creativity. Imagine if such a drug was readily at hand to give to those of us with emotional memories like jealousy, rancor or anxiety. Maybe those of us harboring one or more out of a clinical laundry list of phobias could free ourselves from the memory of fear. Where should we begin? The military complex has a vast amount of cutting edge scientific discovery which flows out of government subsidized research into military applications. Once the military has tinkered around with the new technology it then releases the technology to the commercial and private sectors. The military could be spending time and resources to deal with a widespread and neglected aspect of its “peace keeping” efforts: Post Traumatic Stress Disorder. All of us should encourage the federal government to invest in research which would aid our veterans of war in erasing the memories tied to their PTSD. The first stage in forgetting is remembering to help those who can't remember how to forget.

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