What comes to mind when you think of immortality? Being a two-hundred-year-old vampire, going to heaven or hell, or nothing–an endless void. Regardless, there is a unifying factor in any perspective on the different forms you choose to understand immortality: the preservation of something. In neurological contexts, our memories are the closest link to the past. They are the closest thing we have to immortality as they, by definition, preserve—the memory of remembering and being remembered.
A region in the brain seems to orientate and facilitate memory formation. This region is called the hippocampus. The name hippocampus is from the Greek hippokampus (hippos, meaning “horse,” and kampos, meaning “sea monster”) (Britannica). The hippocampus is bilaterally enclosed deep within the brain in the temporal lobe and is part of the limbic system. The limbic system (primitive brain) comprises brain regions that control functions like hunger, drive, mood, pain, pleasure, and memory.
With this fact about the hippocampus, you might be wondering how it works?
As with anything that deals with human understanding, we don’t truly know. We only know from the parameters we choose to restrict. In the case of the hippocampus, we set the parameters to its perceived function that is more digestible and comprehensible with observable trends. One trend is that is it facilitates “memory consolidation and memory retrieval” (What is the hippocampus? 2021). The hippocampus receives information from the entorhinal cortex, and the information is processed by the pyramidal cell neurons within the hippocampus. The pyramidal cell neurons have two pathways, the polysynaptic pathway, which facilitates learning and memorising, and the direct pathway, which facilitates recollection and spatial recognition (What is the hippocampus? 2021). In other words, stimuli from the environment or surroundings route from the entorhinal cortex and are processed by pyramidal cells in the hippocampus region.
The hippocampus receives information from neuronal transmitters like serotonin, norepinephrine, and dopamine. Likewise, cholinergic and GABAergic projections from the medial septal area also project the hippocampus (Anand 2012). Though modern understanding of memory extends beyond the hippocampus to possibly the neocortical and cerebellar brain regions, the activity in the hippocampus is crucial (Tulving 1997). These projections and interactions in, to, and from the hippocampus promote the sense of memory: spatial, long, and short-term.
According to Psychology Today, memory is the faculty by which the brain encodes, stores, and retrieves information. In other words, it is when something preserves through time. It is the maintenance of an idea, practice, or understanding. For instance, you can learn the route from your room to your garage to access your car for work with spatial memory. You know that same route without needing your phone’s navigation system or signs. However, spatial memory is different from short, and long term memory in that is it more specific. Short and long term memories are more encompassing. Short-term memories are stored for quick access and last for 20 to 30 seconds before decaying (Cherry 2022). All memories were once short-term before becoming long-term. Long-term memories are stored and can last longer (i.e. months to years).
Long term memory has two categories, explicit memories and implicit memories. Explicit memories branch into two categories, episodic and semantic.
Episodic memories are memories of experiences, like the memory of your first kiss or the memory of graduation. These memories usually have an emotional significance to your life. On the other hand, semantic memories are memories of general facts, like the capital of Nigeria (Abuja) or the location of the highest mountain in the world (Mount Everest on the border of China and Nepal). These memories are usually consensus agreements of an idea and often objective (in terms of human parameters). On the implicit side of long term memory, these memories are automatic, meaning they are procedural and skilled related. For example, how to ride a bike or walk with your knees. Nevertheless, spatial, short-term, and long-term memory have in commonality their preservation through time.
So how does this relate to immortality, you might now be wondering?
Immortality is essentially the perseverance of something, and if something can live through time one till time two and beyond, then it is not mortal. The human species have preserved a lot through time despite our mortality. We have been able to maintain knowledge in the forms of traditions, writings, and videos. We share stories through writings and hold on to traditions to preserve the past and our sense of identity. We interact with history and others around us, imprinting a trace of our presence in them and them in us. Every imprinting remains in the person’s mind until it resurfaces (e.g. doing an activity and remembering a late loved one, their presence resurfaces, and there they are again with you). Your presence and theirs intertwine. Not alone are they still alive within you, but they, like you, as long as they are remembered and never forgotten, will always transcend time.
From primitive concepts to sophisticated tendencies, the brain holds the potential to live beyond its time through our current understanding of memory formation in the hippocampus. Memory that resonates within the neuronal network that we experience or imprint in others allows us to remain in existence after death. As a result, we, as humans, live beyond our physical limits of time and become not like the vampires, deities, or voids, but a subtle scent and presence through time. We transcend our conceptual limits and become immortal through memories.
Yassa, M.A. (n.a). hippocampus. Encyclopedia Britannica. https://www.britannica.com/science/hippocampus
Anand, K. S., & Dhikav, V. (2012). Hippocampus in health and disease: An overview. Annals of Indian Academy of Neurology, 15(4), 239–246. https://doi.org/10.4103/0972-2327.104323
NA. (2021). What is the hippocampus? the 3 main functions of our hippocampus – 2022. MasterClass. Retrieved March 1, 2022, from https://www.masterclass.com/articles/hippocampus-explained#what-is-the-hippocampus
Avigan, P. D. (2020). The contributions of the prefrontal cortex, hippocampus, and their interactions to flexible spatial learning and memory [ProQuest Information & Learning]. In Dissertation Abstracts International: Section B: The Sciences and Engineering (Vol. 81, Issue 10–B).
Tulving, E., & Markowitsch, H. J. (1997). Memory beyond the hippocampus. Current Opinion in Neurobiology, 7(2), 209–216. https://doi.org/10.1016/S0959-4388(97)80009-8
Cherry, K. (2021). How does your long-term memory work? Verywell Mind. Retrieved March 1, 2022, from https://www.verywellmind.com/what-is-long-term-memory-2795347
Cherry, K. (2022). What is short-term memory? Verywell Mind. Retrieved March 1, 2022, from https://www.verywellmind.com/what-is-short-term-memory-2795348