What is memory?
Memory is one of the brain’s abilities to acquire, store, or refresh information or live experiences that enter our nervous system via some sensory pathway. It is studied in the fields of cognitive psychology and neuroscience. There are several classifications of memory based on its duration, nature and recall of emotional states.
How does it work?
The functioning of memory is determined by a series of processes or stages that must be carried out in an orderly manner, through various brain structures such as the cerebellum and hippocampus.
The main neurotransmitter involved in the ‘memorisation‘ process is acetylcholine. The preservation process depends on the type of information, its organization, storage capacity, and persistence. The mechanism of memory work is divided into three complex and heterogeneous stages:
- Recording and coding: After the attention role ends, receiving information, collecting and processing it, the role of coding begins, which is the process of converting information/signals coming from the sense organs into a form that the brain can deal with and thus store.
- Storage: in which memory creates a permanent record of the encoded information. Storage time may be short (thirty seconds) or long.
- Retrieval: Retrieval or retrieval of information stored in memory, as a type of response to a specific action or activity.
How long do our memories last?
Memory is the backbone of learning and remembering. Memories can last for minutes or for an unlimited time depending on the kind of memory that is processing them.
Kinds of memory
It is divided into two broad areas, depending on whether it is associated with time (short-term and long-term memory), or with the nature of the memory (declarative and non-declarative memory).
This is also called immediate or working memory. It is the ability to retain an experience in the mind for a few seconds. It is closely linked to the sensory experiences of sight, hearing and touch.
This kind of memory involves continuous repetition of the stimulus that produced it, and allows us to carry out basic and immediate functions, for example, remembering a telephone number when it has been dictated to you.
This is the system by which information is stored and is a priori inactive, but can be recovered by the person as needed. Examples of this are remembering dates, names, people, images, etc. It is within this kind of memory that the learning process takes place, which is why its development is very complex. It is divided into two subtypes:
- Declarative or explicit memory: being known as the ability to bring to awareness specific facts or episodes of our life (it is the “what”). This subtype is known as “everyday memory” and has a high storage limit11.
- Non-declarative or implicit memory: in this kind of memory there is no conscious recall (it is the “how”), and includes previous experiences that help us to perform a task in an “automatic” (priming) way.
Memory loss is the inability to recognise previously acquired information. This apparent “dysfunction” is sometimes only a brain readjustment mechanism to avoid saturation with irrelevant information. It is true, however, that our ability to remember is progressively reduced with time.
Warning signs of memory loss
Some signs of memory loss that may warn of the need to seek medical care are4:
- Mental confusion, inattention and disorientation.
- Symptoms of depression, in some cases with suicidal thoughts.
- Dizziness, language problems, headaches, visual dysfunction and apathy.
Causes of memory loss
There are different causes that lead to a reduction in memory capacity:
- Ageing: as we get older there is a physiological decrease in brain function. This usually means that people have to make a greater effort to recover facts or memories, and more frequent stimuli are required to store them.
- Mild cognitive impairment: this is an alteration of memory, greater than age-related but less than in cases of dementia8.
- Dementia: in these cases, memory loss is caused by a “total erasure” of an event and not the detail, presenting a severe dysfunction of cognitive functioning.
- Affective disorders (depression, anxiety, etc.): in these cases, attention or concentration and short-term memory are mainly affected.
- Others: hypothyroidism, traumatic brain injury, stroke, vitamin B12 deficiency, etc.
Lack of concentration
As previously mentioned, attention or concentration consists of focusing our mind on specific things without being disturbed by other stimuli.
Lack of concentration in young people
Different epidemiological studies report that memory, attention and concentration disorders are quite common in adulthood, but they can also be found in young adults. A large postal study reported a high prevalence of subjectively felt forgetfulness in young (29%) and middle-aged (34%) healthy Dutch subjects.
Causes of poor concentration
Poor concentration or memory loss in young adults is often related to mood (mood dysfunctions) or stress. For example, a neuropsychological study in young adults10 showed some causes of memory-related complaints, such as:
- Environmental changes such as increased demands at work, increased responsibilities, moving house, etc.
- Acute stressors that may have affected memory, such as divorce or death in the family.
- Pathological processes or pharmacological treatments that change the metabolism of catecholamines (acetylcholine).
Exercises for memory and concentration
We have always heard that “the brain is a muscle that needs to be trained” … and this is absolutely true. For this reason, different health organisations, medical societies, NGOs, among others, spend a large part of their work on effective measures to keep cognitive function, especially memory, intact.
Memory defines who we are and allows us to learn to respond to situations and to adapt. This is why doing mental exercises changes and creates new connections in the brain.
How can I train my memory?
There are different ways to train memory, and they are useful at any age. General recommendations4 include physical exercise, following a healthy diet, taking enough rest and sleep, not smoking and moderate alcohol intake, taking part in social activities and avoiding high levels of stress. Exercises to train the brain include the following:
- Card games or puzzles: this helps concentration, promotes patience and reduces anxiety.
- Word search puzzles, crossword puzzles or sudoku.
- Correct some words grammatically.
- Practice antonyms and synonyms.
- Practice spatial location through images…etc.
What to take to improve memory and concentration
Science has shown that proper nutrition is essential for good health, especially at the brain level.
The brain represents 2% of our body weight, yet it requires 20% of the energy we consume. Therefore, a balanced diet is directly related to the well-being of the nervous system and therefore of the memory.
Foods for memory and concentration
Suggested foods that should be consumed regularly in order to keep the memory in good condition include four main groups:
- Omegas: these have been shown to be key to memory, especially DHA and linolenic acid. Their sources are fish, nuts, vegetable oils such as olive, soya and canola.
- Antioxidants: oxidative stress has a negative impact on cognitive function and memory. Plant sources are excellent suppliers of antioxidants, such as red fruits, grapes, tomatoes, nuts, sesame, vegetable oils, green tea and, to a large extent, green leafy vegetables.
- Amino acids: these are part of the so-called neurotransmitters that are responsible for brain responses, including memory. One of them, serine, is involved in the production of acetylcholine, and is found in meat, fish, dairy products, eggs, beans, beans, soya, lentils, pulses, rice, wheat, barley, avocado and quinoa.
- Choline: part of acetylcholine and crucial for memory processes. You can find choline in meat, eggs, poultry and dairy products, potatoes and cruciferous vegetables (such as cauliflower), nuts, seeds and whole grains.
Vitamins for memory and concentration
Vitamins are involved in cognitive functions. Specifically, the B vitamins facilitate nerve connections, the production of neurotransmitters, as well as normal brain metabolism, with vitamins B6, B12 and folic acid (B9) being particularly important in this respect.
The food sources where you can find the B group of vitamins are meat, offal, poultry, fish, eggs, dairy products, pulses, vegetables (avocados, potatoes, broccoli and sweet potato), vegetables such as spinach, mushrooms, whole grains and nuts.
Because of their antioxidant power, vitamin C and vitamin E also promote the well-being of the brain structure. They can be found mainly in citrus fruits and nuts, respectively.
There are also food supplements, either in liquid or in capsule format, which are also sources of vitamins B, C and E as adjuvant intakes.
Memory and concentration supplements for students
Along with a balanced diet and a healthy lifestyle, dietary supplements can be helpful in supplementing the diet of young adults, such as students. As mentioned above, one of the causes for memory “failure” are stressful conditions and lack of sleep. Two things that can happen often during student life.
This is why, along with the general measures mentioned above, a good diet can be supplemented with ingredients such as a vitamin B complex, phospholipids containing choline and serine, omegas, ginseng and vitamins C and E.
- Ansón Artero, L. et al. Cuaderno de ejercicios de estimulación cognitiva para reforzar la memoria. Servicio de Neurología. Consorci Sanitari Integral. Jun. 2015.
- Antikainen, R. et al. Una disminución de las quejas de memoria se asocia con mejoría en el estado de ánimo: un estudio de seguimiento a los doce meses en pacientes deprimidos. Eur. J. Psychiat. Vol. 18, N.° 3, (142-151) 2004.
- ASISPA. 4 ejercicios para la memoria sencillos y eficaces. Jul. 2021.
- Levin, M. C. Pérdida de la memoria. MANUAL MSD. Ago. 2021.
- Lewis, J. E. et al. The effects of twenty-one nutrients and phytonutrients on cognitive function: A narrative review. J Clin Transl Res. 2021 Aug 4;7(4):575-620.
- Makkar, R. et al. Nutraceuticals in Neurological Disorders. J. Mol. Sci. 2020, 21, 4424.
- NeuronUP. 5 ejercicios para mejorar la memoria. Dic. 2021.
- Olivera-Pueyo, J. & C. Pelegrín-Valero. Prevención y tratamiento del deterioro cognitivo leve. Psicogeriatría 2015; 5 (2): 45-55.
- Portellano Pérez, J. A. & J. García Alba. Neuropsicología de la atención, la memoria y las funciones ejecutivas. Editorial Síntesis, 2014. ISBN 9788490770269.
- Ruiz-Sánchez de León, J. M. et al. Estudio neuropsicológico de adultos jóvenes con quejas subjetivas de memoria: implicación de las funciones ejecutivas y otra sintomatología frontal asociada. Rev Neurol 2010; 51: 650-60.