Lewis's Theory of Active and Inactive Memory

Although memory has been scientifically researched for approximately 130 years, perhaps the The most relevant discovery to date is that memory is much more complex than anyone could come up with. To imagine. Next, we will talk about one of the theories that have passed most unnoticed throughout the history of the study of this brain process and that, however, it could be closer to its actual operation: Lewis's theory of active and inactive memory.

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What is memory?

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

A short-term memory, located in the prefrontal cortex, which allows us to manipulate information from the external or internal environment (our mind) and has a limited capacity; and a long-term memory, located in the hippocampus and temporal lobe, of an unlimited nature and that stores information permanently.

On the other hand, these traditional theories also point out that

so that the formation of new memories occursThese have to go through a period of instability in which they can undergo modifications, 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 could be forgotten if a series of conditions were met. Based on this effect, in 1979 Lewis proposed an alternative theory.

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Lewis's theory of active and inactive memory

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

Namely; active memory would be made up of changing subsets of all the body's memories that affect our behavior present, and the inactive memory would be formed by all those permanent memories, which have the potential to be activated at some point, they are in a state of relative inactivity and have little or no effect on the present behavior of the organism.

Furthermore, he went one step further, arguing that memory does not have specific locations within the brainRather, it is a central processor that is subject to other basic processes such as perception and attention. An active memory is a unique neuronal firing pattern. Different activated memories would reflect different patterns of neuronal density and would not have a specific location.

The student's example

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

A college student just got out of a procedural law exam and is recalling the answers he gave based on what he studied (subset of permanent memories and unconsolidated memories that are active at the time) when suddenly you pass a pastry shop and a smell of food invades you and makes you remember the menu you are going to performed upon arrival home (the perception of the smell directed attention to the food, which in turn activated a permanent memory of the menu of the day that until that moment was inactive).

As can be seen, and as Lewis stated, "active memory is intuitively apparent to immediate consciousness." Consciousness is defined as the ability of the individual to recognize the reality that surrounds him., relate to her and reflect on her and on himself.

Recovering this model

However, this theory was quickly rejected at the time due to its highly speculative assumptions and the lack of a robust empirical test. 40 years later, each new discovery in the field of memory could be related directly or indirectly to the works of Lewis. In the year 2000, Nader, Schafe, and Le Doux argued that new memories should be renamed active memories. Sara, in the same year, urged the entire scientific community to consider memory as a dynamic process.

In 2015 Ryan, Roy, Pignatelli, Arons, and Tonegawa, among others, stated that each memory is a characteristic neural firing pattern (currently called cell engrams). These same authors also conjectured in favor of another of Lewis's hypotheses, which postulates that amnesia is not a destruction of memory, but an inability to recover it, that is; an inability to activate a dormant memory.

Bibliographic references:

• Lewis, D. J. (1979). Psychobiology of active and inactive memory. Psychological bulletin, 86 (5), 1054-1083. doi: 10.1037 / 0033-2909.86.5.1054
• Nader, K., Schafe, G. E., and Le Doux, J. AND. (2000). Fear memories require protein synthesis in the amygdala for reconsolidation after retrieval. Nature, 406 (6797), 722-726. doi: 10.1038 / 35021052
• Sara, S. J. (2000). Retrieval and reconsolidation: toward a neurobiology of remembering. Learning & Memory, 7 (2), 73-84. doi: 10.1101 / lm.7.2.73
• Ryan, T. J., Roy, D. S., 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