Андрей Фоменко – The Power Of Youth. How To Tune Our Mind And Body For A Long And Healthy Life (страница 11)

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).

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.

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].

Neurobiologists from the University of Jyväskylä (Finland) found during experiments in animals that prolonged aerobic exercise increases neurogenesis in the adult brain[55]. The hippocampus of mice that ran long distances showed increased formation of new neurons after eight weeks.

Scientists identify three main factors that affect neuroplasticity at any age[56]:

● 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]. 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]. 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]. 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]. 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].

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].

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].

The basis of this diet:

1) greens, vegetables and berries, olive oil;

2) beans;

3) whole grains;

4) fish;

5) wine/black grape juice.

The MIND diet also recommends limiting red meat, butter and margarine, cheese, sweets and candy, fried food, and fast food.

NEUROTRANSMITTERS ARE THE LANGUAGE THE BRAIN SPEAKS

Neurotransmitters are chemical substances that transmit signals between two nerve cells or between neurons and other cells in the body. They affect many psychological and physiological functions of the body, as well as mood, memory, learning ability, and concentration, regulate sleep, appetite, and vital signs: heart rate, breathing, digestion features, etc.

Neurotransmitters are often confused with hormones. This is not surprising, because their regulatory functions are very similar, and, in addition, many neurotransmitters have hormone-double: there is dopamine-hormone and dopamine-neurotransmitter, and noradrenaline-neurotransmitter and noradrenaline hormone, etc. Even though these substances have the same chemical formulas, they differently affect the body.

The main difference is that hormones are produced only in the endocrine glands, while neurotransmitters are produced exclusively by neurons. Therefore, the effect of neurotransmitters is limited to the nervous system, and hormones act on the periphery and cannot penetrate the brain they are hindered by the blood-brain barrier.

The difference between hormones and neurotransmitters with the same chemical formula can be seen in noradrenaline. The hormone noradrenaline is produced in the adrenal glands during stress. Its effect is similar to adrenaline, but it has a more pronounced vasoconstrictive effect and has less effect on the heart rate, a less significant effect on the smooth muscles of the intestines, etc. That is, the sphere of influence of the hormone noradrenaline is internal organs. It is controlling the body's response to stress.

At the same time, the neurotransmitter noradrenaline "reigns" in the brain: in stressful situations, it is responsible for the sense of excitement and risk enjoyment, increasing aggression and reducing anxiety. In its more "peaceful" hypostasis, it helps to memorize information better in training.

At what point does the nerve impulse "lose" its electrical nature and "switch" to a chemical one? This occurs when the signal coming from the nerve cell body along the axon reaches an area called the synapse. The synapse is a contact point between the end of one projection and the beginning of another one or the cell membrane to which a signal is to be delivered. Between them, there is a space 10–50 nanometers wide, which is called the synaptic cleft.

The terminal along which the signal came is called presynaptic. Neurotransmitters are synthesized there: they are contained in small vesicles. Their release into the synaptic cleft occurs in response to reaching a threshold action potential, i.e., the nerve impulse shall be characterized by a certain intensity.