Neural connections in the brain cause complex behavior. Neurons are small computers that can exert influence only when connected in a network.
Control of the simplest elements of behavior (for example, reflexes) does not require a large number of neurons, but even reflexes are often accompanied by a person's awareness of the response of the reflex. The conscious perception of sensory stimuli (and all the higher functions of the nervous system) depends on a huge number of connections between neurons.
Neural connections make us what we are. Their quality affects the work of internal organs, intellectual abilities and emotional stability.
"Wiring"
Neural connections of the brain - wiring of the nervous system. The work of the nervous system is based on the ability of a neuron to perceive, process and transmit information to other cells.
Information is transmitted through a nerve impulse. The behavior of a person and the functioning of his body is completely dependent on the transmission and receipt of impulses by neurons through the processes.
The neuron has two types of processes: axon and dendrite. The axon of the neuron is always one, it is through it that the neuron transmits momentum to other cells. It receives an impulse through dendrites, of which there may be several.
Many (sometimes tens of thousands) axons of other neurons are "summed up" to dendrites. Dendrite and axon are in contact through the synapse.
Neuron and synapses
The gap between the dendrite and the axon is the synapse. Because the axon is the “source” of the impulse, the dendrite is the “receiving” one, and the synaptic cleft is the site of interaction: the neuron from which the axon comes is called presynaptic; the dendritic neuron is postsynaptic.
Synapses can form between the axon and the body of the neuron, and between two axons or two dendrites. Many synaptic connections are formed by a dendritic spine and axon. Spines are very plastic, have many forms, can quickly disappear and form. They are sensitive to chemical and physical influences (injuries, infectious diseases).
In synapses, information is most often transmitted through mediators (chemicals). The mediator molecules are released on the presynaptic cell, cross the synaptic cleft and bind to the membrane receptors of the postsynaptic cell. Mediators can transmit an exciting or inhibitory (inhibitory) signal.
The neural connections of the brain are the connection of neurons through synaptic connections. Synapses are a functional and structural unit of the nervous system. The number of synaptic connections is a key indicator for brain function.
Receptors
Receptors remember every time they talk about drug or alcohol addiction. Why does a person need to be guided by the principle of moderation?
The postsynaptic membrane receptor is a protein tuned to mediator molecules. When a person artificially (with drugs, for example) stimulates the release of mediators into the synaptic cleft, the synapse tries to restore equilibrium: it reduces the number of receptors or their sensitivity. Because of this, the natural concentration levels of mediators in the synapse cease to have an effect on neural structures.
For example, people who smoke with nicotine change the receptor susceptibility to acetylcholine, desensitization (decrease in sensitivity) of the receptors occurs. The natural level of acetylcholine is insufficient for receptors with reduced sensitivity. Because acetylcholine is involved in many processes, including those related to concentration of attention and a sense of comfort; smokers cannot get the beneficial effects of the nervous system without nicotine.
However, the sensitivity of the receptors is gradually being restored. Although this can take a long time, the synapse returns to normal and people no longer need third-party stimulants.
Neural network development
Long-term changes in neural connections occur in various diseases (mental and neurological - schizophrenia, autism, epilepsy, Huntington, Alzheimer's and Parkinson’s diseases). Synaptic connections and the internal properties of neurons change, which leads to disruption of the nervous system.
The development of synaptic connections is responsible for the activity of neurons. “Use or lose” - the principle underlying the neural networks of the brain. The more often neurons “act”, the more connections between them, the less often, the fewer connections. When a neuron loses all its connections, it dies.
Some authors have expressed other ideas that are responsible for regulating the development of neural networks. M. Butz associates the formation of new synapses with the tendency of the brain to maintain a “habitual” level of activity.
When the average level of neuron activity falls (for example, due to trauma), neurons make new contacts, and the activity of neurons increases with the number of synapses. The opposite is also true: as soon as the level of activity becomes more than the usual level, the number of synaptic compounds decreases. Similar forms of homeostasis are often found in nature, for example, when regulating body temperature and blood sugar.
M. Butz M. Butz noted:
... the formation of new synapses is due to the desire of neurons to maintain a given level of electrical activity ...
Henry Markram, who is involved in a project to create neural brain simulations, emphasizes the development prospects of the industry for studying impairment, restoration and development of neural connections. A group of researchers has already digitized 31 thousand rat neurons. Rat brain neural connections are presented in the video below.
Neuroplasticity
The development of neural connections in the brain is associated with the creation of new synapses and modification of existing ones. The possibility of modifications is due to synaptic plasticity - a change in the "power" of the synapse in response to activation of receptors on the postsynaptic cell.
A person can memorize information and learn through the plasticity of the brain. Disruption of the neural connections of the brain due to craniocerebral trauma and neurodegenerative diseases due to neuroplasticity does not become fatal.
Neuroplasticity is due to the need to change in response to new living conditions, but it can both solve human problems and create them. A change in synapse power, for example, during smoking, is also a reflection of brain plasticity. It is so difficult to get rid of drugs and obsessive-compulsive disorder precisely because of non-adaptive changes in synapses in neural networks.
Neurotrophic factors have a great influence on neuroplasticity. N.V. Gulyaeva emphasizes that various disorders of neural connections occur against the background of a decrease in the levels of neurotrophins. Normalization of the level of neurotrophins leads to the restoration of neural connections in the brain.
All effective drugs used to treat brain diseases, regardless of their structure, if they are effective, they normalize local levels of neurotrophic factors by one mechanism or another.
Optimization of the levels of neurotrophins cannot yet be carried out by direct delivery to the brain. But a person can indirectly affect the levels of neurotrophins through physical and cognitive loads.
Physical exercise
Research reviews show that exercise improves mood and cognitive abilities. Data suggest that these effects are due to changes in the level of neurotrophic factor (BDNF) and the improvement of the cardiovascular system.
High levels of BDNF were associated with better spatial abilities, episodic and verbal memory. Low levels of BDNF, especially in the elderly, correlated with hippocampal atrophy and memory impairment, which may be associated with cognitive problems in Alzheimer's.
When exploring the treatment and prevention of Alzheimer's, researchers often talk about the indispensability of exercise for people. Thus, studies show that regular walking affects the size of the hippocampus and improves memory.
Exercise increases the rate of neurogenesis. The emergence of new neurons is an important condition for retraining (gaining new experience and erasing the old).
Cognitive load
Neural connections of the brain develop when a person is in a stimulated environment. New experience is the key to increasing neural connections.
A new experience is a conflict when a problem is not solved by the means that the brain already has. Therefore, he has to create new connections, new patterns of behavior, which is associated with an increase in the density of spines, the number of dendrites and synapses.
Learning new skills leads to the formation of new spines and the destabilization of old connections of spines with axons. A person develops new habits, and old ones disappear. Some studies have linked cognitive impairment (ADHD, autism, mental retardation) with abnormalities in the development of spines.
Spines are very plastic. The number, shape and size of spines are related to motivation, learning and memory.
The time required to change their shape and size is measured literally in hours. But it also means that new compounds can disappear just as quickly. Therefore, it is best to give preference to short but frequent cognitive loads than long and rare.
Lifestyle
Diet can enhance cognitive abilities and protect the neural connections of the brain from damage, help them recover from illnesses and counteract the effects of aging. It seems that they have a positive effect on brain health:
- omega-3 (fish, flax seeds, kiwi, nuts);
- curcumin (curry);
- flavonoids (cocoa, green tea, citrus fruits, dark chocolate);
- B vitamins;
- Vitamin E (avocado, nuts, peanuts, spinach, wheat flour);
- choline (chicken, veal, egg yolks).
Most of these products indirectly affect neurotrophins. The positive effects of diet are enhanced with exercise. In addition, a moderate calorie restriction in the diet stimulates the expression of neurotrophins.
To restore and develop neural connections, the exclusion of saturated fats and refined sugar is useful. Sugar-added foods lower neurotrophin levels, which negatively affects neuroplasticity. And the high content of saturated fats in food even inhibits brain recovery after traumatic brain injuries.
Among the negative factors affecting neural connections: smoking and stress. Smoking and prolonged stress have recently been associated with neurodegenerative changes. Although short-term stress can be a catalyst for neuroplasticity.
The functioning of neural connections also depends on sleep. Perhaps even more than from all the other factors listed. Because sleep itself is “this is the price we pay for brain plasticity.” (Sleep is the price we pay for brain plasticity. Ch. Cirelli - C. Cirelli).
Summary
How to improve the neural connections of the brain? Have a positive impact:
- physical exercise;
- tasks and difficulties;
- full sleep;
- balanced diet.
Negative effect:
- fatty foods and sugar;
- smoking;
- prolonged stress.
The brain is extremely plastic, but to “sculpt” something from it is very difficult. He does not like to waste energy on useless things. The fastest development of new connections occurs in a conflict situation, when a person is not able to solve the problem by known methods.