Memory (process)

Memory is a function of the brain that allows the organism to encode, store and retrieve information from the past. Some theories state that it arises as a result of repetitive synaptic connections between neurons, which which creates neural networks (so-called long-term potentiation). However, although this phenomenon has been studied for more than 30 years in animals, there are still not enough studies on its existence in the human cerebral cortex.

Space memory experiment in mice.

Memory allows us to retain past experiences and, according to the temporal scope, is conventionally classified into: short-term memory (consequence of the simple excitation of the synapse to strengthen or sensitize it temporarily), medium-term memory and long-term memory (consequence of a permanent reinforcement of the synapse thanks to the activation of certain genes and the synthesis of the corresponding proteins). The hippocampus is a brain structure related to memory and learning. An example that supports the aforementioned is Alzheimer's disease, which attacks the neurons of the hippocampus, which causes the person to lose memory and often does not even remember their relatives.

In practical terms, memory (or, better, memories) is the expression that learning has occurred. Hence, memory and learning processes are difficult to study separately.

The study of memory tends to focus mainly on hominids, since they present the most complex brain structure on the evolutionary scale. However, the study of memory in other species is also important, not only to find neuroanatomical and functional differences, but also to discover similarities. Animal studies are also often carried out to discover the evolution of memory capacities and for experiments where it is not possible, due to ethics, to work with human beings. In fact, animals with a simple nervous system have the ability to acquire knowledge about the world, and create memories. This ability reaches its maximum expression in humans.

The human brain of a standard adult individual contains about 100,000,000,000 (one hundred billion) neurons and about 100 trillion interconnections (synapses) between them. Although the memory capacity of the brain is unknown for sure, since no reliable means of calculating it is available, estimates vary between 1 and 10 terabytes. According to Carl Sagan, we have the capacity to store information in our minds equivalent to 10 trillion encyclopedia pages.

There is no single physical location for memory in our brain. Memory is scattered across several specialized locations. While the memories of our earliest childhood are stored in some regions of the temporal cortex, the meaning of words is stored in the central region of the right hemisphere and the learning data in the parieto-temporal cortex. The frontal lobes are dedicated to organizing perception and thought. Many of our automatisms are stored in the cerebellum.

The first studies on memory began in the field of philosophy, and included techniques to improve memory. Late 19th century and early XX, memory became the paradigm par excellence of cognitive psychology. In recent decades it has become one of the main pillars of a branch of science known as cognitive neuroscience, an interdisciplinary nexus between cognitive psychology and neuroscience.

History

Scheme of various types of memory as literary genre

The psychologist William James () was the first to make a formal distinction between primary memory and secondary memory (short-term memory and long-term memory, respectively). This distinction lies at the heart of Atkinson and Shiffrin's (1968) influential multiple storage model.

Hermann Ebbinghaus (1885) is generally considered to have pioneered the experimental study of memory, having used himself to study basic phenomena such as learning and forgetting curves and inventing nonsense syllables for said purpose.

For much of the first half of the 20th century, memory was not a respectable topic for experimental psychologists, reflecting the dominance of behaviorism. However, some behaviorists—particularly Americans—studied so-called verbal behavior using associated pair learning, in which pairs of unrelated words are represented, where the first member of the pair represents the second. stimulus and the second the response.

This associationist approach gave the study of memory a firm position within the behaviorist conceptual framework, and since then it has been observed more clearly in the interference theory, which is one of the main theories of forgetting.

Phases

Scheme of the memorizing process, according to:Abenteuer Psyche (Gabriele Amann, Rudolf Wippinger), 1. Auflage, Abbildung 3.16

In the process of storing knowledge in memory it is possible to differentiate the following phases:

• codification or Registration: transformation of sensory information into recognizable and manipulable elements by memory through verbal codes (palabras, numbers, letters) and visual codes (images and figures). This encoding is not neutral, but from all the sensory information that comes, the one that interests and is interpreted according to previous experiences and ideas. In this operation, attention and concentration are decisively influenced. Some obstacles to attention and concentration are external distractions (conversations, radio, television, noises, etc.); internal distractions (concernings, indecision, personal problems, lack of interest, etc.); and physiological distractions (physics, diet, sleep, diseases, etc.).
• storage: retention of information in order to keep it and recover it when necessary. Depending on where data are stored, more or less time will remain in memory, from a few seconds to a lifetime.
• recovery, Remember to remember or collection: location and update of the stored information. This is what we call remembering, that is, evoking and recognizing the information acquired and stored in memory. Recovery means bringing information to consciousness.

Sensory memory

The ability to record sensations perceived through the senses is called sensory memory. It constitutes the initial phase of the development of the care process. This memory has a great capacity to process a large amount of information at the same time, although for a very short time.

There is a series of stores of information coming from the different senses that prolong the duration of the stimulation. This generally facilitates their processing in the so-called working memory.

The most studied stores have been those of the senses of sight and hearing:

• The iconic warehouse is responsible for receiving visual perception. It is considered a deposit of great capacity in which the stored information is an isomorphic representation (with the same structure) of the reality of a purely physical and non-categorical character (the object has not yet been recognized).

This structure is able to maintain nine elements approximately, for a very short time interval (about 250 milliseconds). The elements that will eventually be transferred to the operational memory will be those to which the individual pays attention.

• The eco-store, for its part, keeps the auditory stimuli stored until the receiver has received enough information to be able to process it definitively in the operating memory.

Short-term memory

Short-term memory is the system where the individual manages the information from which he is interacting with the environment. Although this information is more durable than that stored in sensory memories, it is limited to approximately 7±2 items per 30 seconds (span of memory) if not reviewed.

This capacity limitation is manifested in the effects of scoop and latest. When a group of people is presented with a list of elements (words, pictures, actions, etc.) to be memorized, after a short time they more easily remember those items that were presented at the beginning (scoop) or the that were presented at the end (recency or ultimacy) of the list, but not those in between.

The "scoop effect" decreases with increasing list length, but ultimacy does not. The explanation given for these data is that people can mentally review the first elements until they are stored in long-term memory, and instead they cannot process the intermediate elements. The last items, for their part, remain in working memory after the learning phase is over, so they would be accessible when the list was recalled.

The general functions of this memory system include information retention, support in learning new knowledge, understanding the environment at a given moment, formulating immediate goals, and solving problems. Due to capacity limitations, when one person performs a certain function, the others cannot be carried out at that time.

Subsystems

Operating memory or working memory is made up of several subsystems, namely: a supervisory system (the central executive) and two specialized secondary stores of verbal information (the articulatory loop) and visual or spatial (the viso-spatial agenda).

• The neuronal system central coordinates system resources and distributes them by different warehouses, called slavesaccording to the function to be performed. It therefore focuses on active control tasks on the passive elements of the system; in this case, the information stores.
• The joint or fonological loop, for its part, is responsible for passive storage and active maintenance of spoken verbal information. The first process causes the information to be lost in a short period of time, while the second —repetition — allows the temporary information to be refreshed. In addition, it is responsible for the automatic transformation of the language presented visually to its phenological form, so, for practical purposes, it processes the entire verbal information. This is shown when it comes to remembering a list of letters presented in a visual or auditory way: in both cases, a list of similar sound words is more difficult to remember than one in which these are not so similar. Also, the storage capacity of the “artic link” is not constant as it was believed (the classic 7±2), but decreases as the words to be remembered are longer.
• La visopacial agenda is the warehouse of the system that works with visual or spatial elements. Like the previous one, your task is to keep this type of information. The storage capacity of elements in the "visoespatial agenda" is affected — as in the " articulatory link" — by the similarity of its components, as long as it is not possible to translate the elements into their verbal code (e.g. because the "joint link" is occupied with another task). Thus, it will be more difficult to remember a brush, a pen and a pencil to remember a book, a ball and a pencil.

Consequences of limited resources

It has been investigated how limited "working memory" resources affect the execution of several concurrent tasks. In research of this type, a group of people is told to perform a primary task (for example, writing an article) and a secondary task (for example, listening to a song) at the same time. If the main task performs worse than when it is done alone, it can be seen that both tasks share resources.

In general terms, performance in simple tasks worsens when they require the participation of the same secondary store (for example, writing a text and paying attention to what is said in the song), but not when the exercises are carried out carried out separately in the two stores or subsystems (for example, listening to news and watching images on television). When task complexity increases and information processing controlled by the "central executive" is required, performance on both tasks becomes slower, but not worse.

In addition, it has been shown^{[citation needed]} that older people show worse performance in tasks that require the use of the “central executive” component of memory of work. On the contrary, the tasks that require the phonological loop will not be so affected by age. At present, this question is not yet clarified.

Long-term memory

Long-term memory (MLP) is a store that is commonly referred to when we talk about memory in general. It is where lived memories are stored, our knowledge about the world, images, concepts, action strategies, etc.

It has an unknown capacity and contains information of a different nature. It is considered the "database" in which the information is inserted through the "operating memory", for later use.

Classification by type of information

A first distinction considered within the MLP is the one established by Squire's model in 1992^{[citation required]} between declarative memory and the non-declarative memory known as procedural. The «declarative memory» is the one in which information about facts is stored, while the non-declarative memory serves us to store information based on procedures and strategies that allow us to interact with the environment, but whose implementation in progress takes place unconsciously or automatically, making it practically impossible to verbalize it.

Non-declarative (implicit) memory

"Non-declarative memory" can be considered a performance system (praxia), involved in learning different types of skills (also known as procedural memory) that are not represented as explicit information about the world. This type memory is activated automatically, as a sequence of guidelines for action (procedure), in response to the demands of a task. It consists of a series of motor repertoires (writing) or cognitive strategies (doing a calculation) that we carry out unconsciously.

The learning of these skills is acquired gradually, mainly through execution and the feedback obtained; however, instructions (declarative system) or imitation (mimicry) can also influence. The degree of acquisition of these skills depends on the amount of time spent practicing them, as well as the type of training that is carried out. As the "law of practice" predicts, in the first trials the speed of execution undergoes a rapid exponential increase, which slows down as the number of practice trials increases.

The acquisition of a skill implies that it is carried out optimally without demanding too many resources of attention, which can be used in another task at the same time, so that said skill is carried out automatically.

The unit that organizes the information stored in the «procedural memory» is the production rule that is established in terms of condition-action, and the condition is considered to be an external stimulation or a representation of it in working memory; the action is considered a modification of information in working memory or in the environment.

The characteristics of this memory are important when trying to develop a series of rules that allow to obtain a good execution in a determined task. This memory is explored through praxis, which is the ability to voluntarily start motor programs already learned: a specific movement or gesture, handling objects that require a sequence of gestures, etc.

Declarative (explicit) memory

The «declarative memory» contains information referring to knowledge about the world and about the experiences lived by each person (episodic memory). An example of it is New Year's Day, which we remember and for everyone is different. It also contains information referring to general knowledge, especially regarding concepts extrapolated from lived situations (semantic memory). While semantics is more objective and an example of it is that the color red is something we learned from childhood and that it is the same for everyone, taking into account these two subdivisions of declarative memory is important to understand how the information is represented and is differentially recovered.

The «semantic memory» accounts for a store of knowledge about the meanings of words and the relationships between these meanings, and constitutes a kind of mental dictionary, while the «episodic memory» represents events or occurrences that reflect details of the situation experienced and not only the meaning.

The organization of the contents in the «episodic memory» is subject to spatiotemporal parameters; that is, the events that are remembered represent the times and places in which they occurred. However, the information represented in "semantic memory" follows a conceptual pattern, so that the relationships between concepts are organized according to their meaning.

Another characteristic that differentiates both types of representation refers to the fact that the events stored in the «episodic memory» are those that have been codified in an explicit way, while the «semantic memory» has a capacity to infer and is capable of manage and generate new information that has never been explicitly learned, but that is implicit in its contents (understanding the meaning of a new phrase or a new concept using already known words).

There is also “photographic memory”, which is the ability of an individual to remember events even after many years with incredible precision. This type of memory is usually very common in people with Asperger syndrome.

Conscious immanent memory

The «immanent conscious memory» refers to a particular type of memory consisting of the projection of a subset of long-term memories onto consciousness. The thesis of conscious immanent memory was postulated by Federico González, an Argentine psychologist, who defined it as:

A projection of the long-term episodic memory of consciousness, made moment by moment. The thesis of conscious memory (MIC) maintains that a compacted fragment of information from the long-term episodic memory system (LM) is projected on consciousness, as a mnemic macroprint. MIC is consciously experienced as a background that gives meaning to the current experience. In this sense, consciousness is a synthesis that simultaneously amalgamates memory with present experience. Consequently, from the perspective of MIC, consciousness constitutes the integrative condensing of a subset of long-term memory linked to the present perceptual and ideative consciousness. In short, MIC is a substructure of the mind that includes a set of past experiences that is reflected or "incrusted" on consciousness.

The thesis of conscious immanent memory has been applied to explain a vast set of phenomena of mental life such as: some aspects of subjective time such as the sensation of duration and the dimensionality of antiquity of memories, the notion of personal identity, the nature of phenomenological retentions and protections and the general orientation of spatiotemporal reality.

The conscious immanent memory thesis assumes that present consciousness contains much more information than what is attributed to it in short-term storage (STP). It also relativizes the postulate that in order to fix new information in long-term memory it is necessary to carry out an internal mental review of it. On the contrary, the hypothesis of a permanent self-save mechanism is supported that would allow syntheses of episodic experiences to be stored without deliberately seeking to do so.

Conscious Immanent Memory has also been applied to understand some type of dream where in the dreamer's experience events are taken for granted that, strictly speaking, did not occur during the dream.

The memories

Memories are images from the past that are stored in memory. They serve us to bring something or someone to the present. They are also defined as a reproduction of something previously learned or experienced, so they are directly linked to the experience.

Neural connections in the cortex are stimulated by information and strengthened and linked to the emotional context in which they were formed. Once encoded, it resides in the region of the cortex where the information was perceived and processed. When necessary, or triggered by emotion, that memory is activated to be used as working memory.

According to psychoanalysis, clinging to a memory can lead to depression and, in extreme cases, even a break with current reality.

The memories of a human collective give us a closer approximation of reality than history itself, since it tends to skip individual facts to focus on global events.

From phenomenology, the philosopher Paul Ricoeur also explains that memory is an image. By remembering, as they say, we represent a past event, thus constituting a common structure between memory and imagination at the moment that the representation of something absent takes place in our minds..

Pathologies

Alzheimer's disease is a type of progressive dementia caused by the development of neurofibriliary plaques and tangles in different regions of the cerebral cortex and hippocampus. At first, these knots and plates are concentrated in the middle temporal region, this area is related to the establishment of new explicit memories. This area is vital for the establishment of episodic memory and contributes to the formation of new semantic memories.

Apolipoprotein E (APOE) is essential for lipoprotein catabolism. In addition, it has been linked to cardiovascular diseases. APOE E4 has been related to a greater susceptibility to developing Alzheimer's. APOE4 tends to cause amyloid buildup in the brain some time before the first symptoms of Alzheimer's appear. Despite recent findings, the presence of the apolipoprotein E gene does not explain all cases of Alzheimer's disease.

Quantitative changes

Amnesia

Poor memory is caused by biological factors or deficiencies outside its normal functioning. Amnesia is the absence of memories of a certain period of life. The subject is usually aware that they are memories that existed, but have been lost. They can be partial or total.

• Partial Amnesia: affect the memories of a small field of visual, hearing or verbal memory. It may be present in organic disorders of the brain, lesions of the cerebral cortex due to trauma, circulatory deficiency, intoxications or psychogenic disorders. If amnesia is organic etiology, it is usually definitive, while the temporary amnesia of psychogenic etiology is usually temporary.
• Total Amnesia: is the one that becomes extended to all elements and forms of knowledge, which corresponds to a certain lapse of the life of the subject. According to the chronology of the forgotten lapse, it is divided into:
  • Atrograde or fixing: inability to evoke recent facts, but if it achieves old memories. They are usually temporary, but they can become definitive, as is the case with dementia.
  • Amnesia retrograde or evocation: it is the difficulty to evoke the memory of preserved experiences of the past and that at other times have been able to recover.
  • Global or retrograde amnesia: simultaneously affects the fixing of present events and the evocation of past memories. It is observed in the terminal periods of dementia.

Hypomnesia

It is the decrease in memory capacity due to a difficulty both in fixation and in evocation. It is seen in psychiatrically healthy people with deep concerns that command attention, as well as in patients with neuroses.

Hypermnesia

It is the increase or hyperactivity of memory, frequent in manic or delusional patients, and also occurs in subjects with special memory training.

Dysmnesia

It is a quantitative alteration that always translates into a decrease in memory, makes it impossible to evoke a memory at a given moment and evokes others in a blurred or unclear way.

It is so named because of the difficulty in evoking a memory at a certain moment, but which can later be evoked spontaneously. This occurs in normal people sporadically, when trying to remember proper names, formulas, etc. This is one of the initial symptoms that occurs in old age. And permanently at the beginning of dementia.

Qualitative changes

They have been grouped under the name of paramnesia, that is, false recognitions or inaccurate memories that do not conform to reality. The main ones are:

• Phenomenon of the already seen (Let me go.): it is the impression that a current experience has been experienced in the past and in the same way. It can be observed in people without any mental suffering or in subjects with neurosis or schizophrenia.
• Phenomenon of the never seen (jamais vu): feeling of never seeing or experiencing anything that is already known in reality.
• Memory Illusion: is the deforming evocation of a living, to which details created by fantasy were added. It is observed in people without mental suffering and in subjects with delusions or schizophrenia.

Memory loss treatments

Some experiences and research suggest that the consumption of omega 3 fatty acid has beneficial effects on brain development, and on processes such as memory and concentration. There are also studies that suggest that the consumption of omega 3 during Pregnancy can have a good influence on the baby, and even groups of school-age children noticeably increased their performance after ingesting omega-3-rich fish oil pills.

Another of the effective aids to improve retention consists of dedicating a good part of the study time not to reading but to the mental review of what has been read, to its orderly reproduction without resorting to the book except when the reading fails. memory. In this way, not only retention, but also the mechanisms for capturing what is retained, are consolidated and perfected. In some cases, the time spent fruitfully on this mental review has reached 80%.

An association between memory disorders and gluten consumption has been demonstrated, both in people with celiac disease and in people with non-celiac gluten sensitivity (tests negative for celiac disease but improvement when gluten is removed from the diet). Although its role is controversial, a gluten-free diet appears to exert a protective effect on memory disturbances, the more effective the shorter the delay from the onset of first symptoms. (See also Gluten-Related Neurological Disorders.)

Forgetting mechanisms

Forgetting is normal, even necessary, as it prevents us from accumulating an excess of useless data. Imagine for a moment that you were able to remember absolutely everything you have learned and experienced throughout your life. Therefore, it is about remembering only what is important.

Forgetfulness can be due to several causes:

• expiration: The stored data can be diluted over time. And this makes sense in the sensory memory, and in the short and medium periods, because it is the way they do not get saturated.

We cannot find an explanation for the fact that things that were stored in long-term memory are forgotten, since its capacity is practically unlimited. Some researchers claim^{[citation needed]} that memories are kept for life, and what is missing is the way to access them.

The agenda effect has been known since the release of electronic agendas, today reinforced by the Google Effect, which is the tendency to forget information that can be found on the Internet using search engines, instead of making an effort to remember it.

This forgetful effect produced when surfing the net also appears when using other technologies such as cameras. In an experiment conducted at the Fairfield University Museum of Art, Lady A. Henkel, Ph.D., discovered that visitors who took photos of the exhibits had poorer recall of both what objects they had seen and of details. of these, in comparison with those visitors who had limited themselves to observing. This occurred despite the fact that both groups of visitors spent the same amount of time viewing each work. The explanation for these results is that, on many occasions, people trust technology (a camera in this case) to store part of the memories for us. This forgetting effect could be counteracted if, later on, we spent enough time looking again at the photographs taken, which would reinforce the memory of those moments, strengthening them in long-term memory.

• Access problems: Sometimes we cannot access the content of our memory, especially if stress makes us produce hormones (glucocorticoids) that block the access function. Through some memory exercises we can increase the possibility that this does not happen.
• Elimination: It appears in the case of painful, frustrating and disturbing information and when extreme or traumatic situations have been experienced. Faced with this oblivion mechanism, memory exercises are useless. However, some unpleasant experiences and memories can be used to improve memory.

The 7 sins of memory (according to Schacter)

Default:

• 1. Step of time
• 2. Distract: You state that, according to the author, the lack of attention is more responsible.
• 3. Block: 'I got it on the tip of the tongue.'

For commission:

• 4. Misconception: To attribute a memory to a wrong source. For example, to attribute ideas that are not really ours.
• 5. Suggestability: Memories are influenced by external agents. For example, we don't remember well what happened any day. But as a friend tells you, you remember him as such, even if there are false data.
• 6. Sesgo: The memory is influenced by our current state (feelings, point of view).
• 7. Persistence: Permanence of memories we wish to forget.

Memory and psychology

Memory is a brain function that is involved in all human learning processes. It is as vital to the survival of the individual as it has been to the survival of the species. This is a common point with many of the animal species, if not all, and when we consider novel aspects under study, such as cell memory, it is also a common point with plants and other living beings.

Human memory, like the human being itself, is complex and fascinating. It is to her that we pay the most attention and to which we demand the greatest effort in our lives, since our life exists thanks to our memory. Life is made up of memories. Memory is the ability to acquire, store, and retrieve information. We are who we are thanks to what we learn and remember. Without memory we would be unable to perceive, learn or think, we would not be able to express our ideas or have a personal identity, because without memories it would be impossible to know who we are and our lives would lose meaning. This conceptual map consists of a summary of the subject of human memory that we are studying. From the main title "Human memory" come different sections into which the topic is divided.

Firstly, there is the «complexity of memory», which explains what memory consists of and the research that has been carried out on it, both those that study repetition, schemata and short-term memory. Another of the sections is that of the neuropsychology of memory, which already talks about the most recent and scientific research on our memory and the processes that take place in our brain so that it works correctly.

The last two sections that appear are those of the basic processes of memory, in which the three basic functions of this are named, and the structure and functioning of memory, in which the three memory systems are named that communicate and interact with each other. These systems were recognized by psychologists Richard Atkinson and Richard Shiffrin through the development of the multistore theory of memory.

There are failures in the process and function of memory that are not properly forgetfulness or difficulties in storage or retrieval, but are distortions of information. Some of these disorders reach a degree of illness already and are called "paramnesias"; others, on the contrary, are quite infrequent or mild in their occurrence. In both cases the manifestations may be similar, but differ in intensity or frequency.

Among the most frequent anomalies we find:

• «Your face seems familiar to me»: it occurs when we find a person we know (or think we know) but it is impossible to identify (or determine who has such a similarity).
• Forget the name: occurs when we fully identify the face as someone we know, but we cannot remember the name.
• Sensation of knowing: This is the case where we firmly believe to know something or to know something, but when using that knowledge it fails. This happens to us more often in semantics.
• Phenomenon of "I have it at the tip of my tongue": It is very related to the previous one and it is specifically the inability to find the right word for what is meant, finding perhaps many associates or related but not exactly matching the wanted.
• Temporary lagoon: it is when you forget some fragments of something or what happened in a specific period, usually when in that period there is nothing relevant and functions or work on learners are being carried out. Example, when we forget part of the usual journey to our house: we do not remember when we pass by certain point (for which we had to have passed).
• Falsification of memory or false memories: the psychic apparatus creates memories to fill gaps in memory. This type of disorder tends to be highly problematic for the subject and deserves special care from psychology.
• Let go.: it is an anomaly of recognition that implies that we experience this situation of "I have already seen it" or "I have already lived it", even knowing that it is the first time we see it or live.
• Jamais vu: is the case against the previous one. Here, although the individual knows and knows that he knows a certain situation and remembers it, he does not experience any sense of familiarity.

Complementary bibliography

• Mind and Brain, 43, 2010, pp. 47-89.
• Angel Barco, “The Matter of Memories: Neuronal Circuits and Molecular Cascades”, Mind and Brain, 40, 2010, pp. 24-33.
• Juan Carlos López, «Sinapsis para recordar», Mind and Brain, 54, 2012, pp. 42-48.