What if you could erase your ex from your mind?

Memory is a complex network of interconnected experiences

Our memories are not isolated snapshots but a complex web of interconnected experiences that define who we are.

Memory engrams, the physical traces of memory in the brain, are spread across multiple brain regions that work together to store and retrieve our experiences. 

The smell of your grandmother's perfume might instantly bring back her kitchen, her voice but also other associated childhood emotions. These sensory details and feelings are woven together across different brain regions. 

The interconnection of experiences is what makes our memories so resilient but also what complicates any effort to erase or alter them.

Clementine is not the only thing that disappears

This concept of interconnectedness is depicted in ‘Eternal Sunshine’, where the selective erasure of memories isn’t as simple as removing a single, isolated memory. 

The film visualizes memory as a network, where erasing one memory has a cascading effect on others. 

This mirrors the scientific understanding that memories are not stored in isolation; rather, they are part of a larger web that links experiences together, sharing emotions, sensory cues, and contexts. 

As Joel’s memories of Clementine are erased, memories from unrelated parts of his life also begin to fade, demonstrating how deeply interconnected our personal histories are.

Because of the nature of engram complexes, targeting a single memory without disturbing others is extremely difficult. Joel and Clementine try to save her from being erased by hiding her in memories where she never originally appeared. 

However, Lacuna Inc. eventually tracks her down, leading to the destruction of Joel’s unrelated childhood memories. 

Eternal Sunshine captures the fragility of memory networks with striking clarity, showing how attempts to erase one part can destabilize the whole.

Why should we even try?

The ability to erase a specific event without inadvertently changing the underlying neural architecture that supports other related memories is a significant scientific and ethical challenge.

Despite the inherent risks, the potential to relieve suffering through memory manipulation (as part of therapeutic treatment) cannot be overlooked.

The ability to selectively alter memories could have profound therapeutic implications for conditions such as PTSD, where individuals are haunted by persistent, traumatic memories. 

In PTSD, traumatic memories overwhelm patients' daily lives. 

The ideal treatment would reduce the emotional pain of these memories without erasing the memories themselves.

Therefore, this is where the movie and the real-world neuroscience separate: Unlike in Eternal Sunshine, we can’t completely erase specific memories due to the interconnected nature of our memory networks.

Rather than erasing a memory entirely, the focus of growing research is to reduce the emotional distress associated with specific memories, making it less disruptive to an individual’s well-being.

Maybe we can weaken traumatic memories

Studies in mice show that a brain region called the amygdala, which handles our emotional memories, can be modified to change how we learn to associate emotions with experiences (Pape & Pare, 2010; Johnsen et al., 2014).

An important breakthrough comes from Josselyn and Tonegawa, who discovered that certain brain cells become more active and physically change when we form memories. 

This means that by strengthening or weakening these connections, we might be able to change how easily we recall certain memories, opening up new possibilities for treatment.

Just like in ‘Eternal Sunshine’, targeting these brain mechanisms could lead to future treatments that reduce the emotional pain of traumatic memories while keeping the actual memory intact for learning and growth

From Science Fiction to Scientific Reality

The field of memory manipulation has evolved significantly over the past century, largely due to advancements in experimental technologies. 

Today, we can directly manipulate the engram cells (those neurons that represent memories) using optogenetics, a technique that uses light to control specific brain cells, and other tools that allow for precise control over individual neurons.

In 2014, Nabavi and colleagues demonstrated the ability to both turn off and reactivate memories using long-term potentiation (LTP, which strengthens brain connections) and long-term depression (LTD, which weakens them). 

By applying light stimulation to specific neural pathways in mice, they could control the recall of a traumatic memory, effectively creating a causal link between synaptic changes and memory retrieval. 

This experiment not only provides evidence that memories are stored in brain cell connections but also shows that we might one day be able to selectively manipulate those connections to alter memory retrieval.

Rewriting Reality: When Memories Can Be Moved and Made Artificially 

In ‘Eternal Sunshine’, as memories of Clementine are systematically erased, Joel tries to preserve her by moving her into unrelated memories, creating dreamlike distortions of his past. 

Vetere and colleagues demonstrated the ability to create entirely artificial memories in mice. By replacing real sensory experiences with direct light stimulation of brain circuits, they created fully artificial memories without any actual experience.

This technology opens up fascinating possibilities for memory manipulation, including the potential for implanting or altering memories in a controlled and targeted manner. 

Just as ‘Eternal Sunshine’ shows how erasing memories creates space for new experiences while distorting emotional connections to the past, studies with animal models demonstrate how artificial memories can be created by manipulating the specific brain cells that naturally encode experiences. 

These findings blur the line between authentic and manufactured memories, raising profound questions about the nature of our personal histories and emotional connections to our past.

Are We Ready for Memory Manipulation in Humans?

One of the closest real-world parallels to memory manipulation (though far les precise than in the movie) is propranolol therapy, where a drug is paired with the reactivation of traumatic memories. 

By interfering with memory reconsolidation, propranolol can reduce the emotional weight of those memories. 

In 2018, the researcher Brunet reported remission rates of 70 percent and more in PTSD patients after using 50 to 80mg of propranolol in several sessions. 

Brunet claimed in an article in Wired.com that his reconsolidation therapy was better than fiction: “Because you don’t forget your memory - who would want to forget their love story? Instead, the therapy “reconsolidates” the memory by removing the pain from it.” 

However, even if this study sounded promising, other researchers have shown no evidence for the efficacy of propranolol on traumatic memory disruption.

The ethical stakes are high. Memory interventions could ease PTSD and anxiety disorders, yet they also raise questions about identity. 

The real question is not only whether we can alter memory, but whether we should. If we could erase our painful memories, would we? And more importantly, would it change who we are?