Can you erase your memory?

What is memory?

Our brain is a wiggly structure in our skull, made up of roughly 100 billion neurones. It is a wondrous organ, capable of processing 34 gigabytes of digital data per day, yet being able to retain information, and form memory – something that many would argue, defines who we are.

So.. what is memory? And how does our brain form them? Loosely defined, memory is the capacity to store and retrieve information. There are three types of memory: short-term, working, and long-term memory (LTM). Today, we will be focusing on LTM. In order to form LTM, we need to learn and store memory. This follows the process of encoding, storage, retrieval, and consolidation.

In order to understand the biochemical attributes of memory in our brain, a psychologist, Dr Lashley, conducted extensive experiments on rats to investigate if there were specific pathways in our brain that we could damage to prevent memory from being recalled. His results showed that despite large areas of the brain being removed, the rats were still able to perform simple tasks (Figures 1-2).

Lashley’s experiment transformed our understanding of memory, leading to the concept of “engrams”. Takamiya et al., 2020 defines “memory engrams” as traces of LTM consolidated in the brain by experience. According to Lashley, the engrams were not localised in specific pathways. Rather, they were distributed across the whole of the brain.

Can memory be erased?

The concept of memory erasure is huge and complex. In order to simplify this, let’s divide them into two categories: unintentional, and intentional.

Let’s take amnesia for example. This is a form of unintentional memory ‘erasure’. There are two types of amnesia: retrograde amnesia, and anterograde amnesia. Retrograde amnesia is the loss of memory that was formed before acquiring amnesia. On the other hand, anterograde amnesia is the inability to make new memories since acquiring amnesia. Typically, a person with amnesia would exhibit both retrograde, and anterograde amnesia, but at different degrees of severity (Figure 3).

Can we ‘erase’ our memory intentionally? And how would this be of use to us? This is where things get really interesting. Currently, the possibility of intentional memory ‘erasure’ is being investigated in patients for the treatment of post-traumatic stress disorder (PTSD). In these clinical trials, patients with PTSD are given drugs that block these traumatic memories. For example, propranolol, an adrenergic beta receptor blocker impairs the acquisition, retrieval, and reconsolidation of this memory.

Incredible, isn’t it? Although this is not the current standard treatment for PTSD, we can only imagine how relieving it would be for our fellow friends who suffer from PTSD if their traumatic memories could be ‘erased’. However, with every step ahead, we must always be extremely cautious. What if things go wrong? We are dealing with our brain, arguably one of the most important organs in our body after all. Regardless, the potential for memory ‘erasure’ in treating PTSD seems both promising and intriguing, and the complexities and ethical considerations surrounding such advancements underscore the need for careful and responsible exploration in the realm of neuroscience and medicine.

Written by Joecelyn Kiran Tan

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