Duke Medical Ethics Journal

Biological Mechanism

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The hippocampus is a crucial region in the brain that plays a central role in the formation and storage of memories. It is located in the medial temporal lobe and converts short-term memories into long-term memories, a process known as memory consolidation. Utilizing mice models and optogenetics (targeted stimulation of neurons using light), neuroscientists have started to map out which hippocampal cells are activated upon positive, negative, or neutral memories (Free, 2020). “Research led by neuroscientists Steve Ramirez from Boston University and Briana Chen from Columbia University, followed on from previous research finding optogenetic manipulation of cells in a mouse hippocampus can alter behavioral expression of positive and negative memories. The scientists wondered whether different parts of the animal's hippocampus could be associated with different emotional associations to certain memories” (Haridy, 2019). The outcome indicated a clear contrast in emotional affect on the top and bottom parts of the hippocampus. When memory cells in the base of the hippocampus were stimulated, negative experiences connected to certain memories appeared particularly intense. On the other hand, “stimulating cells in the top part of the hippocampus resulted in memory recall without powerful traumatic emotional associations” (Haridy, 2019). 

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What these findings imply is that it is when the lower region of the hippocampus becomes overactive that memories of negative experiences become emotionally disturbing. Suppressing this overactivity (via medication or brain stimulation therapies) can possibly be used as a treatment for PTSD, anxiety, and various other psychiatric disorders.

 

This research is further famously backed by Dr. Brian Wiltgen of the UC Davis Center for Neuroscience and Department of Psychology, who discovered that by placing probes into the brains of mice, bad experiences could be “erased” with pulses of light. "We were able to turn off a certain memory in the hippocampus in mice," he said (Fell, 2016). Wiltgen genetically modified mice so that when nerve cells were stimulated, they would fluoresce green and express a protein, which let the researchers turn off particular cells using light. Because of this methof, the study could track and examine exactly which nerve cells in the cortex and hippocampus were activated in memory retrieval, and switch them off with light directed through a fiber-optic cable (Fell, 2016).

 

Implications for PTSD & Addiction

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The biggest implications and clinical applications for memory editing that I noticed were for recovering addicts and individuals suffering from PTSD. Firstly, memory manipulation can focus on memories associated with drug cravings, helping drug addicts by lowering their intensity. By modifying the emotional and motivational facets of drug-related memories, individuals can experience less cravings and a higher chance of resisting relapse. Furthermore, memory manipulation can be utlized to break down the mind’s associations between drug-related memories and the pleasurable effects of such narcotics, which can break the cycle of addiction.

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Second, focusing on specific neurons involved in the formation and retrieval of traumatic memories, optogenetic stimulation can alter with the reconsolidation process. This can aid in numbing the emotional intensity of traumatic memories and contribute to therapeutic interventions. However, these approaches can be deemed controversial on the premise of numerous philosophies related to identity and wellness of humanity. 

 

Philosophical Perspectives: The Self 

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Understanding the basis of memory and its connection to self-identity has been a focus for neuroscientists, physicians, writers, and philosophers for decades. I will be discussing a few key philosophical perspectives. 

 

Firstly, one of the popular views on editing memories is the Lockean view (John Locke), which states personal identity correlated to memory continuity (Robillard, 2016). According to Locke, a person is a chain of overlapping memories connecting past and present experiences. Hence, the Lockean philosophy proposes that genuine memory is an essential element of personal identity (Robillard, 2016). Memory manipulation challenges this notion. 

 

On the other hand, Jean-Paul Sartre’s existentialist authenticity philosophy argues that individuals should live per what they consider is their “true selves”. If memory editing is seen as a means for individuals to align their memories with their authentic selves or overcome trauma, Sartre’s ideology suggests it is philosophically justified (Guignon, 1998). Furthermore, under a utilitarianism philosophy, classical utilitarians believe that proper action is the one that results in the most happiness, the one that minimizes suffering for all parties involved (Gau, 2006).  Under that chain of reasoning, if a memory-removal can operate as a procedure to bring about more happiness than would otherwise be possible, the use of it is justified on utilitarian grounds. “It should be pointed out though that there is a big ‘if’ in the claim above—it is not at all clear whether this sort of procedure could be implemented in such a way that it would increase happiness overall” (Gau, 2006). 

 

Memory Editing Consequences Depicted in Media  

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Cinema has multiple examples of memory editing gone wrong. One of the most prominent is the 2004 classic Eternal Sunshine of the Spotless Mind. The film delves into the erasure of painful memories via a medical procedure after a failed relationship leads two ex-lovers to a doctor requesting to forget one another—the ultimate message being that memories of both a joyful and painful nature contribute to personal growth. Denied the chance to remember lessons from heartbreak, the main characters cannot grow from it. The film also “subtly critiques modern neuroscience’s contemporary reliance on quick fixes and escapes from emotional pain rather than confronting and processing it” (“The Astromech”, 2023). 

 

The value of authentic memories has even been highlighted in animated children’s films such as Disney’s Inside Out. The film toys with the notion of Memory Islands, each signifying an integral part of a young girl Riley's (the main character) identity (e.g., Goofball Island, Family Island, Friendship Island). ‘Editing, ‘altering’, or ‘misplacing’ core memories throughout the film causes hindrance to and weakens these islands, influencing Riley's sense of self and causing her to act out (Robb, 2015). The film sheds light on the fact that altering memories can have cascading impacts on cognitive processes and decision-making. The movie further highlights tthe importance of sadness and unhappy memories in growth and development, as Riley’s initially adverse experience of moving to San Francisco ultimately brings her closer to her parents and makes her more resilient.  

 

Conclusion: Overall Ethical Benefits and Drawbacks  

 

The clinical advantages of being able to medically alter memories appear promising on the surface level, as it would relieve countless patients of their suffering due to psychiatric disorders. More breakthroughs in research related to memory editing can lead to enhanced management of phobias, anxiety disorders, and even depression treatment. The process can be utilized to alter depressive thought patterns associated with specific memories without the need for extensive psychotherapy, time, and medications—potentially reducing society’s prevalence of suicide. However, there is so much we still do not understand about memory formation, storage, and recall. Venturing deeper into this scientific pursuit without agreeing on a philosophical standpoint and fully understanding the basis of human memory is dangerous not only because of unintended consequences on cognitive function that can result from not understanding the brain enough (at this time) but also for personal identity and autonomy.