by Carrie Sun

“Blessed are the forgetful: for they get the better even of their blunders”—Friedrich Nietzsche wrote in his philosophical work, Beyond Good and Evil. Nietzsche gave an aphorism, but not the method by which you and I might be bestowed such blessings. How exactly, then, do we forget blunders, trauma, and stress? How do we forget the memories that wrest from us our sense of well-being and happiness; the memories which pool as an unfortunate wellspring of such mental conditions like Posttraumatic Stress Disorder (PTSD)?

Dr. Linda de Voogd is a postdoctoral researcher at New York University investigating the effects of stress on memory. A neuroscientist by training, she studies how our brains encode stressful events, how these emotional memories develop, and why some of them form successfully while others fail. In the Netherlands, where Dr. de Voogd spent her earlier years, among the most oft-used treatment for PTSD is eye movement desensitization and reprocessing (EMDR).  And yet, she says, “No one really knows how this works, why this works, so there are lots of skeptics.” 

At the 32nd meeting of the Consciousness Club on Wednesday, March 14, 2018, Dr. de Voogd presented her research showing the neurobiological mechanisms by which EMDR likely disrupts the formation and retrieval of emotional memories.

Dr. de Voogd started with a story: Her family had a holiday home to which they retreated, every month or two, from when she was about five years of age to fifteen. She doesn’t remember much from those days—what she ate on a certain day, what outfit she wore, which friends she saw. She does, however, remember one extraordinarily vivid memory in living detail, the memory of her arriving at her holiday house only to discover it had been broken into, the gate ajar, the door open, the TV gone. She remembers it as if it were yesterday, she said. But how? 

Neuroscience tells us that in the process of new memory formation, memories first need to be stabilized for which the hippocampus plays an important role. The hippocampus is involved in the encoding of events and binding of details such as sight, smell, and other stimuli. Memories are then strengthened when the hippocampus receives emotional context from the amygdala, a nearby almond-shaped structure involved in the perceiving and processing of threats. This hippocampus-amygdala functional connectivity provides the basis for the strong formation of emotional memories.

To illustrate this process, Dr. de Voogd conducted a study where she had one set of participants look at photos of animals and another set look at photos of fruits. As you might expect, brain imaging showed different parts of the brain activating when looking at different photos. Next, she made one set emotional while keeping the other set constant—emotion, in this case, being stress, spurred by electrical shocks administered through electrodes placed on the tip of participants’ fingers. After the shock (or, as she called it, “learning”) takes place, re-imaging of the brain showed increased levels of activity not only in the regions governing emotion, but also in the parts responsible for encoding memory. It’s true: the amygdala and hippocampus work in tandem to form, strengthen, and recall emotional memories.

But we don’t merely want to know how memories are formed. We want to know if memories can be targeted, forgotten. We want to know the neurological processes by which memories are fortified because understanding them could lead to their disruption, thereby introducing noninvasive, non-pharmacological ways to treat metaphysical trauma.

Dr. de Voogd continued her study. Some of her participants were then asked to play a game involving digits flashing in front of them at an alarmingly fast pace; participants were additionally asked to press a button if the digit they saw was the same digit as two slots prior. For example: 3, 7, 3, 4, 2, 5, 1, 7, 1, 4, 8, 4, … Now imagine that each number flashed for a split second. (Yes, this game requires focus, to say the least!)

Interestingly, it is this simple movement of the eyes and concentration on the game that leads to the suppression of activity in the amygdala. Participants who had learned the emotional memory of the shock and upon which eye movements were administered showed significant reductions of anxiety responses measured through sweating of the fingers. We knew EMDR to be an effective treatment of PTSD but never how—until now. It isn’t the eye movement per se, but rather the engaging in a cognitively demanding activity that disrupts normal brain processes, including the processes for forming and retaining stressful memories. Or put simply: if you want to forget emotional memories, do something cognitively distracting or demanding when recalling them.

A peppy Q&A segment followed the conclusion of Dr. de Voogd’s formal presentation. 

One woman asked about exposure therapy and whether there is any evidence suggesting it might alter the physical structure of the brain. Dr. de Voogd responded with a most apropos statement: “The question is what changes the brain.” Exercise, studying, recalling—everything we do influences on the brain, she said, but exactly what our physical and mental activities do to the brain, and how, is very difficult to understand. For example, if you were previously afraid of spiders but are no longer, is it because your memory of arachnophobia got erased, or because you have a new memory of spiders being non-threatening? Neuroscience, specifically research in humans, is not yet at a place where we can answer these questions, she said.

Another woman asked about childhood trauma and the effect of time on the stabilization of memory. Dr. de Voogd explained that the older the memory, the more difficult it is to disrupt. Newer memories are, plainly, easier to destabilize.

The spirited Q&A discussion continued for over an hour, poring through topics like emotional suppression and how talk therapy might work by restructuring the brain; how emotional memories might be “exotic” memories capable of producing a generative model of future events from just one instance, versus neutral memories needing large amounts of sample data to produce any learning; how the intrinsic positivity or negativity of a memory is irrelevant, but what is relevant is the valence of the memory and the arousal engendered during recall; and how emotional memories are an elemental part of the human experience, how being well-adjusted through confronting and selectively forgetting traumatic memories may prove to be maladaptive in other situations. 

No one disagrees that the nature of memory is complicated. I think, however, the most pressing questions arising from Dr. de Voogd’s research are the normative sort: Should we, actually, desire to forget trauma? Should we arrest control of memory selection from that which is unexplained (our unconscious, God, or whatever theory your beliefs will allow) and use this modern science—these technologies—to produce designer selves? Should we be (are we already?) our own maker? 

Oliver Sacks, in his book of essays, The River of Consciousness, wrote: “Nothing was more central to the formation of identity than the power of memory; nothing more guaranteed one’s continuity as an individual. But memories shift … and that their essence, indeed, is recategorization.” Memories are alive. Memories hold the power to individual identity, and with that the bright and hopeful power to collective consciousness and societal, cultural identity. Let’s not recategorize casually and lose the continuity of history, of our forefathers who graveled the yellow brick road on which our greatest quests—to understand the origins of the mind and the universe—have lain. Perhaps we are already the blessed, alive at a time when it might be a possibility, at all, to one day peek behind the curtain.