Lewis theory of active and inactive memory

Although memory has been the subject of scientific research for about 130 years, perhaps the most relevant discovery to date is that memory is much more complex than anyone could have imagined. Next, we’ll talk about one of the more unnoticed theories that has passed throughout the history of studying this brain process and which, however, might be closer to how it actually works: Lewis theory of active and inactive memory.

    What is memory?

    Traditional theories, and generally accepted by the scientific community, postulate that memory is a basic cognitive process divided into two types.

    Short-term memory, located in the prefrontal cortex, which allows information to be manipulated from the external or internal environment (our mind) and has limited capacity; and a long-term memory, located in the hippocampus and the temporal lobe, of unlimited character and which stores information permanently.

    On the other hand, these traditional theories also point out that for the formation of new memories to take placeThese have to go through a period of instability during which they can undergo changes, but once they reach long-term memory, they remain unchanged.

    However, in the late 1960s, several groups of researchers (including Lewis), investigating the phenomenon of amnesia in rats, observed effects that could not be explained by traditional theories of memory.

    They saw that memories consolidated in long-term memory they could be forgotten if a number of conditions were met. Based on this effect, Lewis proposed in 1979 an alternative theory.

      Lewis theory of active and inactive memory

      The author postulates that there are no types of memory, but that memory is a dynamic process composed of two states: An active state where all memories, new and consolidated, could be changed and forgotten, and an inactive state where all memories remain stable.

      In other words, it is; active memory would be made up of changing subsets of all memories in the body that affect our current behavior, and inactive memory would be made up of all of those permanent memories, which have the potential to be activated at some point, which are in a relative state. inactivity and have little or no effect on the body’s current behavior.

      Furthermore, it was a step further, arguing that memory it doesn’t have specific locations in the brainBut it is a central processor which is subject to other basic processes such as perception and attention. Active memory is a unique neural trigger pattern. Different activated memories would reflect different patterns of neuronal density and lack a specific location.

      The student’s example

      The following example will allow a better understanding of this theory:

      A student has just graduated from a procedural law exam and remembers the answers he gave based on what he studied (subset of permanent memories and unconsolidated memories that is active at the moment) when it suddenly drops out of a pastry shop and it is overwhelmed by the smell of food and makes you remember the menu you will make when you get home (the perception of the smell draws attention to the food, which in its tour triggered a permanent memory menu for the day that had been inactive until then).

      As we can see, and as Lewis says, “active memory is intuitively apparent to immediate consciousness”. Consciousness is defined as the ability of the individual to recognize the reality around him, Talk to her and think about her and herself.

      Get this model

      However, this theory was quickly dismissed at the time due to its highly speculative assumptions and the lack of a solid empirical contrast. 40 years later, every new discovery in the field of memory could be directly or indirectly related to Lewis’ work. In 2000, Nader, Schafe and Le Doux argued that new memories should become active memories.. Sara, the same year, urged the entire scientific community to view memory as a dynamic process.

      In 2015, Ryan, Roy, Pignatelli, Arons, and Tonegawa, among others, said that each memory is a pattern of characteristic neural traits (currently called cell engrams). These same authors also conjectured in favor of another hypothesis of Lewis, which postulates that amnesia is not a destruction of the disc, but an inability to recover it, that is to say; an inability to activate inactive memory.

      Bibliographical references:

      • Lewis, DJ (1979). Psychobiology of active and inactive memory. Psychological Bulletin, 86 (5), 1054-1083. doi: 10.1037 / 0033-2909.86.5.1054
      • Nader, K., Schafe, GE and Le Doux, JE (2000). Memories of fear require protein synthesis in the amygdala to consolidate after recovery. Nature, 406 (6797), 722-726. doi: 10.1038 / 35021052
      • Sara, SJ (2000). Recovery and reconsolidation: towards a neurobiology of memory. Learning and Memory, 7 (2), 73-84. doi: 10.1101 / lm.7.2.73
      • Ryan, TJ, Roy, DS, Pignatelli, M., Arons, A. and Tonegawa, S. (2015). Engram cells retain memory under retrograde amnesia. Science, 348 (6238), 1007-1013. doi: 10.1126 / science.aaa5542

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