The enigma of memory has long captured the attention of scientists and thinkers alike. The Greek philosopher Plato once theorized that our brain and memories function like a wax tablet, where impressions are engraved and later read. Though outdated, Plato’s metaphor remains useful to illustrate how our memories are created, stored, and retrieved.
You may have heard that the structure in our brain known as the hippocampus is fundamental for memory. Although the hippocampus plays a large role in converting short-term memories into long-term, it is not where our memories are permanently stored. Instead, our brains distribute memories in a variety of locations depending on their type. For example, declarative memories — facts and experiences that require no conscious effort to recall, such as a birthday or where you live — are stowed outside our brain’s hippocampus, scattered among the entorhinal, perirhinal, and parahippocampal cortices in the medial temporal lobe. Recollections of how something looks, for instance, are typically found in the visual cortex of the occipital lobe, the portion of our brain associated with vision, as well as the prefrontal cortex, the section of our brain responsible for working memory and decision-making. Similarly, a recollection of a song’s melody also activates our brain’s prefrontal cortex and the auditory cortex, responsible for the processing of sounds. Ultimately, no one area in the brain is responsible for all aspects of our memory.
When we form a memory, the neurons inside our brain strengthen their connections, a phenomenon known as synaptic plasticity. Over time, the repeated use of these pathways results in the “storage” of specific memories. During recall, these neural pathways reactivate together, resulting in the remembrance of the original memory. Cue-dependent memory is a fascinating example of just how strong these associations can become. Have you ever heard a song from your past and instantly remembered what life was like when it first came out? A single sound, scent, or object can take you back in time to a vivid recollection of people, events, and feelings from the past. It is as though our minds are a time capsule just waiting for the right key to open it.
While our brain may not literally be made out of wax, it shares the same plasticity that Plato once described. Being constantly remolded and rewired, our mind is capable of more than we know. Each time we recall a memory, we are not just remembering it — we are recreating it through the activation of billions of neural pathways. This endless capability to evolve is what makes our brain such an enigma, and why the mystery of memory may never truly be solved.
“Each time we recall a memory, we are not just remembering it — we are recreating it through the activation of billions of neural pathways.”
