Extra, Extra: Eternal Sunshine on a Spotless Mind, in real life!

28 12 2010

I was recently sent this article, by an esteemed veterans officer who is deeply concerned about the welfare of our nation’s veterans plagued by PTSD.

Traumatic Memory Erasure on Horizon
November 23, 2010, Baltimore Sun, featured on military.com

The article triggered a lot of comments from the readers: questions about mind control, jokes about forgetting ex-spouses, and government conspiracy and poisoning. This article was also splatttered all over the media, with titles like,  “Fear Deleted!” and “Memories Erased!”

I have to blame the authors, in part, for this uproar. In an attempt to make the data sexier (scientists have to market too) they chose this title, “Calcium-Permeable AMPA Receptor Dynamics Mediate Fear Memory Erasurefor their manuscript.

While it’s clear that the researchers intents are therapeutic, the news article ends with a cautionary comment,”…trying to eliminate all the memories could significantly alter a person’s personality and history. So could forgetting a whole person after a painful loss or breakup, as depicted in the 2004 movie “Eternal Sunshine of the Spotless Mind.

There’s no question where the writer leaves the reader, wondering whether scientists have the power to erase your mind and memories and ultimately who we are.

I too believe that these pharmacotherapies for PTSD need to be monitored in their progress and application, but not for the same reasons. Ultimately, I don’t believe that these technologies have the ability to erase memories, and quite frankly the researchers don’t at all describe this. The current studies and these data are not really about erasing “memories”.  They are more about decreasing the connection of powerful debilitating emotions (like extreme fear) with an event.  You would still remember gruesome details of bombings, etc, but you wouldn’t associate such debilitating fear when you remembered them and you’d also be less likely to fixate on and globalize that fear to a motorcycle back-firing, etc.

Current PTSD research aims to disrupt strong unwanted emotional associations with memories. In particular, the focus is fearful memories.  Fear, is a healthy thing.  It is evolutionarily favorable to have a sense of fear and to know when to generalize those fears (some snakes are poisonous; I should use caution when I see a snake). A healthy brain is also adaptable and flexible (I should use caution when I see a snake, but in this case, I’ve just seen a stick in the leaves).  However, people that suffer from PTSD, have their fears hijacked so that fears may not be only to a specific event, but also have become generalized this fear (all stick-like objects are just as bad as an actual snake, all sticks induce fear like snakes). Research is working to dissociate a memory of an event from a debilitating emotional response.

Memory formation and learning works in two ways 1) making associations and 2) breaking associations. Breaking and then re-making associations is what allows us to learn and adapt to our environments. Neuroscientists like to call this “plasticity” in the brain.  A healthy brain is “plastic”, not stiff and unchanging. A healthy brain is constantly building and rebuilding, kinda like the Fraggle-Doozer relationship. Neuroscientists find this fascinating and believe understanding plasticity and how to manipulate it could have therapeutic benefit for a wide range of psychiatric and even movement disorders.

Drugs that are being developed, just as the ones being developed by Dr. Huganir, the researcher featured in the above article, typically utilize a similar model.  The animal model is typically a rodent exposed to stress.  The rodent is placed in a box with two compartments.  When the rodent is in compartment A, the rodent receives a mild shock.  When the rodent is in compartment B, it doesn’t.  The rodent naturally learns to avoid compartment A (even when the shock is no longer administered) because bad things tend to happen in compartment A.  This sounds simple, but a lot of behind the scenes action is happening in the brain in order for this behavior to manifest.  Researchers try to interrupt this learning process with various drugs and then they suggest that this drug may be helpful in disrupting unpleasant stimulus+emotion associations.

You may argue, that this certainly isn’t PTSD.  And no neuroscientist worth her salt would say such a thing.  However, many of these drugs have gone from the rodent model phase to the human PTSD patient therapeutic phase in just this manner.  Researchers have shown that some of these drugs that worked to disrupt the unpleasant stimulus+emotion association in rodents helped PTSD patients, usually in combination with behavioral therapy.  In some cases, the PTSD patients given the drug show greater progress (fewer therapy sessions needed, lower levels of anxiety, etc) than their behavior therapy alone counterparts.

The patients, absolutely, do not have a hole in their memory.  They haven’t forgotten, for instance, that they fought a war, or that people died, or that they are married and are from Idaho. I guess, to some, it may seem disappointing that neuroscience can’t always live up to the expectations of sci-fi movies. In this regard, I don’t worry about erasing people’s minds or memories nor am I disappointed in the findings.

I can see some benefit: rape victims take pill as part of initial care in ER to prevent PTSD onset (which, by the way, does not necessary kick-off immediately after the traumatic event-memories take a long time to form).  But, I worry about messing with our emotional responses to things in general. My biggest concern being that these drugs weaken some memories, but can strengthen others.  For example, one drug being tested in PTSD veteran patients has been shown to improve behavioral therapy sessions and weaken fearful memories.  The same drug has also been shown to increase positive associations with drugs of abuse (promoted cue-induced cocaine relapse in rodents) and can increase memory abilities when given at higher doses (in Alzheimer’s patients). Given that many veterans with PTSD also suffer from drug addiction, discussions about these drugs (for ‘erasing memories’) should include how patients might be even more compelled to take drugs or have more difficulty in their drug treatment programs. Or maybe a seemingly less threatening ‘problem’, but would PTSD therapies qualify for cognitive-enhancement if used outside of the recommended dosing regimens? These questions may not seem as magical as wiping one’s mind clean, but they have equally powerful ethical implications for society. And I’d like to invite readers to explore these (more immediate) concerns before worrying themselves about their spotless minds.