The Power Of Youth. How To Tune Our Mind And Body For A Long And Healthy Life

In turn, the autonomic nervous system is divided into sympathetic and parasympathetic. The sympathetic nervous system is responsible for processes occurring in the waking state. The sympathetic nervous system manages the mechanisms allowing the body to maintain a tone and respond quickly to stressful situations. The parasympathetic system, on the contrary, regulates the processes occurring during rest and sleep: the heart rate slows down, breathing becomes rare, and vessels expand, but digestion, on the contrary, occurs more intensively.

Thus, the nervous system is a complex structure with multilevel regulation, which is carried out at both conscious and unconscious levels. Understanding the principles of the structure and functioning of the nervous system, and knowledge of buttons that we can push through our thoughts, actions, and lifestyle, are essential to preserving health and increasing life expectancy. Before you learn to "negotiate" with your nervous system, you need to understand the "language spoken" by neurons. Such "language" is a special molecule called a neurotransmitter.

HOW MEMORY FORMS AND HOW NOT TO LOSE IT WITH AGE?

Our memory is a unique storage of all the events and feelings in our lives, knowledge gained through spontaneous and focused learning, skills, and experiences. Memory is what makes us who we are, and shapes our personality. Therefore, impairment in the ability to store new memories, which is often seen in old age, reduces the quality of life.

However, the real tragedy is the process of memory degradation, the loss of an entire bunch of memories. This devastating phenomenon is specific to so-called neurodegenerative diseases, the most common of which are Alzheimer's disease and vascular dementia.

To see how to prevent these tragic age-related changes, it is important to understand what memory is, how and where it is formed, and what types of memory there are.

From a neurophysiological perspective, memory is a property of the nervous system that lies in the ability to store information about events in the world around, the body's reactions to these events, and the ability to "work" with this information: to reproduce it (recall) and change it, if necessary. A well-functioning memory is like a computer that stores all the downloaded files and opens them on demand. However, unlike a computer, our memories are not stored in folders – they are "written" in neural connections.

When we encounter new information (for example, when we begin to learn a foreign language) or new experiences (when we try to learn to drive a car), our nerve cells start to form new pathways in the brain with the help of projections and synapses. If we do not go back to that experience again, the connections disappear. Therefore, if a person starts to learn a foreign language, but soon quits, the next time they must learn again almost from scratch.

However, if information or action is referred to repeatedly, a hardly noticeable "path" in thickets of nerve endings gradually turns into a well-trod "road," and then into a high-speed "highway." And now we are, almost without thinking, speaking a new language, and driving on automatic. This indicates that "files" with the necessary information are firmly stored on our "computer."

SHORT TERM MEMORY

Some neural connections exist for a very short time: seconds and minutes, which is characteristic of short-term memory. Short-term memory allows the brain to work with small portions of information coming into it at the current time. Information can come both from external sources (what we see, hear, and feel at the moment) and from the depths of our memory – purposeful, or spontaneous recollection.

Areas in the frontal and parietal lobes of the brain, anterior cingulate cortex, and areas of basal ganglia are responsible for short-term memory.

The information storage time in short-term memory is usually no more than 20–30 seconds, in addition, it holds a very limited amount of information. According to various estimates, in a short time, a person can hold in memory from 4 to 7 objects. But there are also various techniques allowing to increase the number of memorized objects, for example, to group them by some principles or form associations. With constant repetition, "mental objects" move from short-term memory to long-term.

A form of short-term memory is working (operative) memory, allowing one to remember necessary information for just a few seconds. For example, enter the digits of a code sent by a bank to make a purchase, or type the phone number, dictated by a new friend, in the contact book. Working memory state is one of the most significant criteria used to assess a person's cognitive reserve. Its impairment is often observed with brain aging and can be considered one of the first signs of age-related dementia.

LONG TERM MEMORY

Unlike short-term memory, long-term memory is quite capable, both in terms of storage time (many memories can last until the end of life) and in terms of volume. In addition, many parts of the brain are involved in the formation of long-term memories. Long-term memory is divided into explicit and implicit.

Explicit memory allows one to consciously operate with information stored in memory, both personal experiences (episodic memory) and facts (semantic memory). The place where episodic explicit memory is stored is an area of the brain called the hippocampus. It keeps the information about, for example, going on vacation with your parents as a child and having coffee with a friend last week. Huge amounts of knowledge are stored in the cerebral cortex: here, for example, information concerning various facts, language, etc. is placed.

Amygdala is responsible for storing emotionally loaded information. Due to the neural connections in this structure, as well as the connections between the amygdala, hippocampus, and cerebral cortex, we can for many years remember situations in which we experienced a strong feeling of joy, shame, or fear. In addition, the amygdala plays a key role in the creation of new memories associated with fear. Therefore, the peculiarities of memory formation in the amygdala are actively studied by specialists involved in post-traumatic stress disorder, people who "run away" from the solution of life's tasks, because of the fear they once experienced, etc.

Implicit long-term memory is formed without consciousness: we can use it without a detailed recall process. The key brain structures responsible for storing implicit information are the basal ganglia and the cerebellum. Basal ganglia (or basal nuclei) are structures that are clusters of gray matter (nerve cell bodies) located deep in hemispheres between the frontal lobes and above the brain stem (on the border of the conscious and unconscious).

The basal nuclei store information about received rewards, and motor skills, so this structure plays a key role in the development of motor habits (piano playing, cycling, dancing, driving), that require less involvement of consciousness in the process of skills implementation as we learn. Lesion of the basal ganglia underlies the motor disorders in Parkinson's disease.

NEUROPLASTICITY

Studies show that as we use our brain, learn, and train our memory, it can change dramatically due to neuroplasticity.

Brain plasticity refers to the ability of the nervous system to change its structure and functions throughout life in response to environmental diversity. The study of neuroplasticity is particularly relevant when it comes to brain aging, recovery from injuries and strokes, and treatment of neurodegenerative diseases such as Alzheimer's and Parkinson's diseases.

Due to neuroplasticity, nerve cells can restore their structure and function, as well as form new synaptic connections. Neuroplasticity is based on two basic processes: the formation of new connections between nerve cells (synaptic plasticity) and the formation of new neurons (neurogenesis).

SYNAPTIC PLASTICITY

In childhood and adolescence, synaptic plasticity is a key property of the brain: the ability to form new connections between neurons helps to learn quickly, to perceive the world. A child's brain forms connections between neurons when encountering a wide variety of information and experiences. As you get older, the number of connections between neurons decreases. This process is called synaptic pruning. The older we get, the more selective our brain becomes in forming connections. It spends resources only on tracing neural pathways for the thoughts we come back to day after day.

Therefore, many adults' brains resemble a "cast" of every day worries. The neural impulses travel along pathways similar to an asphalt road. It takes enough effort and motivation to go off the beaten track and start to "tread" a new path in the neural thicket. At the same time, at any age, repetitive actions gradually lead to the formation of new neural connections.

NEUROGENESIS

It was long believed that the number of nerve cells remained unchanged throughout life: the claim that nerve cells do not regenerate was seen as an axiom. But in recent decades, the findings show that neurogenesis – the production of new neurons by neural stem cells (precursors of all body cells) – is observed in various parts of the brain even in old age.

Scientists from the University of Illinois, after studying postmortem brain tissue of people aged 79 to 99 years, obtained evidence that the formation of new neurons in the hippocampus occurs not only in healthy people but even in patients with cognitive impairment and Alzheimer's disease, although neurogenesis in the latter is significantly reduced compared with older people who do not have cognitive impairment[54 - Tobin M. K., Musaraca K., Disouky A., Shetti A., Bheri A., Honer W. G., Kim N., Dawe R. J., Bennett D. A., Arfanakis K., Lazarov O. Human Hippocampal Neurogenesis Persists in Aged Adults and Alzheimer's Disease Patients. Cell Stem Cell. 2019 Jun 6;24(6):974–982.e3. doi:10.1016/j.stem.2019.05.003. Epub 2019 May 23. PMID: 31130513; PMCID: PMC6608595.].

Neurobiologists from the University of Jyväskylä (Finland) found during experiments in animals that prolonged aerobic exercise increases neurogenesis in the adult brain[55 - Nokia M. S., Lensu S., Ahtiainen J. P., Johansson P. P., Koch L. G., Britton S. L., Kainulainen H. Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained. J Physiol. 2016;594: 1855–1873. doi:10.1113/JP271552.]. The hippocampus of mice that ran long distances showed increased formation of new neurons after eight weeks.

HOW NOT TO LOSE NEUROPLASTICITY IN ADULTHOOD?

Scientists identify three main factors that affect neuroplasticity at any age[56 - Phillips C. Lifestyle Modulators of Neuroplasticity: How Physical Activity, Mental Engagement, and Diet Promote Cognitive Health during Aging. Neural Plast. 2017;2017:3589271. doi:10.1155/2017/3589271. Epub 2017 Jun 12. PMID: 28695017; PMCID: PMC5485368.]:

● physical activity;

● intellectual load;

● nutrition.

A meta-analysis conducted by scientists from the University of Toronto (Canada) shows that physical activity increases the concentration of neurotrophic factors, substances that induce neurons to form new connections[57 - Dinoff A., Herrmann N., Swardfager W., et al. The Effect of Exercise Training on Resting Concentrations of Peripheral Brain-Derived Neurotrophic Factor (BDNF): A Meta-Analysis. PLOS One. 2016;11(9): e0163037. doi:10.1371/journal.pone.0163037.]. Changes can be noticeable after the first session, and the effect lasts for a day or more.

Regular and intensive training maximizes neuroplasticity. However, we can activate the formation of new connections in the brain even with 30-minute walks in which the heart rate reaches 60 % of the maximum, provided, however, that we do it at least three times a week.

A study conducted at Pennsylvania State University (USA) showed that learning a second language leads to anatomical changes in the brain[58 - Li P., Legault J., Litcofsky K. A. Neuroplasticity as a function of second language learning: anatomical changes in the human brain. Cortex. 2014 Sep;58:301-24. doi:10.1016/j.cortex.2014.05.001. Epub 2014 May 17. PMID: 24996640.]. They are expressed in an increase in the density of gray matter, which indicates the formation of new neurons, as well as in the appearance of more structured white matter bands (connections between nerve cells). These changes, which were observed in both young and old people, indicate the activation of two mechanisms underlying neuroplasticity: neurogenesis and the formation of new synapses.

Researchers from the University of British Columbia (Canada) conducted a meta-analysis of 21 studies, all of which examined the effects of meditation on neuroplasticity[59 - Fox K. C., Nijeboer S., Dixon M. L., et al. Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners. Neurosci Biobehav Rev. 2014 Jun;43:48–73. doi:10.1016/j.neubiorev.2014.03.016. Epub 2014 Apr 3. PMID: 24705269.]. Experts found 123 differences in the brains of people committed to meditative practices. For example, there was a cortex thickening (increased volume of gray matter) in the prefrontal area. This indicates the activation of neurogenesis in the part of the brain responsible for memory, planning, and self-control through meditation.

Among the nutrients that help maintain neuroplasticity in adulthood, scientists highlight the following:

1. FLAVONOIDS – compounds found in tea, berries, onions, and red wine. A diet rich in flavonoids is associated with better preservation of cognitive function in the elderly[60 - Devore E. E., Kang J. H., Breteler M. M., Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol. 2012 Jul;72(1):135-43. doi:10.1002/ana.23594. Epub 2012 Apr 26. PMID: 22535616; PMCID: PMC3582325.]. Curcumin, which is found in turmeric root and has antidepressant, anti-inflammatory, neuroprotective, and antioxidant effects.

2. RESVERATROL – a substance found in the wine and juice of black grapes. Evidence suggests that consumption of this flavonoid can slow the age-related decline in intellectual abilities[61 - Farzaei M. H., Rahimi R., Nikfar S., Abdollahi M. Effect of resveratrol on cognitive and memory performance and mood: A meta-analysis of 225 patients. Pharmacol Res. 2018 Feb;128:338–344. doi:10.1016/j. phrs.2017.08.009. Epub 2017 Aug 26. PMID: 28844841.].

3. OMEGA-3 – a polyunsaturated fatty acid found in large quantities of sea and river fish. Just 300 grams of grilled salmon or 3 grams of fish oil contain the daily norm. Studies suggest that omega-3 fights inflammation and stimulates neuronal growth factors[62 - Calder P. C. Omega-3 fatty acids and inflammatory processes: from molecules to man. Biochem Soc Trans. 2017 Oct 15;45(5):1105–1115. doi:10.1042/BST20160474. Epub 2017 Sep 12. PMID: 28900017.].

Based on these studies and others, the team of nutritionist Martha Clare Morris of Rush University Medical Center created the MIND diet to fight Alzheimer's disease. It can reduce the risk of disease by 54 %, which, researchers say, is superior to the Mediterranean diet[63 - Morris M. C., Tangney C. C., Wang Y., Sacks F. M., Bennett D. A., Aggarwal N. T. MIND diet associated with reduced incidence of Alzheimer's disease. Alzheimer's Dement. 2015 Sep;11(9):1007-14. doi:10.1016/j.jalz.2014.11.009. Epub 2015 Feb 11. PMID: 25681666; PMCID: PMC4532650.].

The basis of this diet:

1) greens, vegetables and berries, olive oil;

2) beans;

3) whole grains;

4) fish;