Can you think of your earliest memory of your life, perhaps your first day of school? How did you dress? What did you smell, eat, and do? Were you anxious, scared, or excited? Can you recall the details, like the shutter sounds of your dad’s camera, your heavy backpack, the tight feeling of your new shoes, or the smooth sensation of the scrunchie you had saved for special occasions? It is as if you are reliving the experience. But why do you remember specific events, while forgetting others? How does your brain decide which memories to cherish as masterpieces and which to discard? Does the brain hold onto its work, or does it simply follow trends? The focus of this article is to explore the neurological process of memory genesis: how the brain receives, translates, and stores memories while localizing the brain’s innate potential according to neuroanatomy.
Since the 19th century, it has been clear that memory isn’t a physical thing we can find in any given brain cell, it’s an action, not an object. No single neuron or region has the physical representation of memory; it only exists when a group of neurons fire in a specific pattern. In psychology, when referring to memory, we are describing a process that includes receiving a stimulus and the ability to store and recall its traces. Without memory, the past, present, and future converge and become a lifeless desert. For a process to be called a memory, it must involve chemical and biological changes resulting from an organism’s activity or experience and prove its existence by structural and behavioral adaptation.
Memory isn’t static in terms of permanency and immutability, it’s a dynamic chemical communication between neurons and generally incorporates two forms of existence: short-term and long-term, each with different characters. Short-term memory can only hold a limited amount of information that is readily available for a short period. Long-term memory can maintain an abundant amount of knowledge for prolonged periods. Long-term memory involves sustained exposure to information, encompassing knowledge and abilities, and is categorized as declarative and non-declarative memory. Declarative memory, or explicit memory, is episodic, which includes remembering specific situations, people, and feelings. Non-declarative memory, or implicit memory, incorporates emotional and procedural types. Implicit memory is often more enduring than explicit memory since memory is expensive for the brain to form and store, so it relies on emotion as a kind of barcode to determine what to retain. Additionally, non-declarative memory encodes bodily movements such as riding a bike or tying a shoe. Different types of memories are processed between various regions of the brain. Each memory begins with encoding, followed by storage and retrieval.
Encoding refers to the initial encounter, interpretation, and recoding of a new stimulus, and transferring it from short to long-term memory. The stimulus can be conveyed by one or more of these four doorways: (1) visual; (2) acoustic; (3) semantic; and (4) tactile. Memory genesis isn’t a linear process, it’s encoded in the hippocampus while the frontal lobe gets ready to recall past experiences. The presence of recording, a crucial part of understanding the unknown with the help of the known, is defined as translating the information from the form it is delivered into a form we can make sense of by placing it within the context of stored memory. The process of recording usually occurs subconsciously. This is one reason why people sometimes recall events that never occurred. That is because, during recording, details are added. An example, when you picture all the sights, smells, and sounds of a scene described by someone, you activate a similar brain network as if you were there, so leading questions can plant a false memory.
In a study, psychologists conducted a study by inducing false memories, in which participants hear lists of 15 words that are in the same context such as door, glass, pane, shade, ledge, sill, house, open, curtain, frame, view, breeze, sash, screen, and shutter. Then, participants were given another list with the previous words plus new words and were then asked to pick what they had heard earlier. The subjects falsely recognized words that weren’t on the first list such as window….etc, 84% of the time, which was higher than noticing original words 72% of the time. This phenomenon is referred to as the DRM (for Deese Roediger McDermott) effect, in (Stadler, Roediger, & McDermott,1999) study. The encoding processes take place within the prefrontal, temporal, and parietal lobes, as well as the anterior hippocampus, thalamus, and basal ganglia.
The hippocampus, a vital member of the limbic system, plays a crucial role in learning, memory, and spatial navigation. It is important to note that while the hippocampus is involved in memory processes, it is not the storage place for memories. Instead, it facilitates memory formation through two prominent pathways within the hippocampus: the polysynaptic and direct pathways. The polysynaptic pathway involves afferent connections from the parietal, temporal, and occipital brain areas, reaching the hippocampus via the entorhinal cortex immediately upon receiving a stimulus. The action potentials from the stimulus travel through the fornix to the mammillothalamic nucleus, where processing, regulation of emotions, and the formation and storage of memories take place. Subsequently, these memories can be directed to the neocortex or back to the hippocampus, forming a loop that continues after the initial task has been completed. This background processing in a diffuse mode strengthens the connections, contributing to memory consolidation. The term ‘implanting’ refers to the process of firmly establishing these memories within the brain. It’s important to note that memories are not held within a specific brain structure. Instead, memory is a network of neuronal connections distributed throughout the regions that initially received the stimulus. For instance, when recalling your grandmother’s special dessert, input from the occipital lobe for visual imagery, the temporal lobe for auditory memories, and the gustatory cortex for the taste come together to form the memory. In this way, memory is truly a collaborative effort across different brain areas.
In a nutshell, memory is a collaborative effort among neurons within various brain regions in a parallel manner. The brain, an encased tissue within a bony cage, interacts with the world through electrical signals. Despite the absence of direct sensory experiences like vision, taste, smell, or touch, it still digs its way to unfold what message is carried by the generated action potential and paints it on an old canvas, to make it identical to the earlier memory. Perhaps even your false sense of familiarity is just a modified memory or your brain’s attempt to make sense of your environment. Our exploration of this topic has shed light on memory, the basin’s masterpiece, from formation to recalling.
