Synaptic plasticity of the brain - the ability synapse connections between neurons, change its power depending on the activity of postsynaptic receptors. For a long time it was assumed that the role of the synapse is simply the transmission of information from neuron to neuron or neurons to muscle cells. In addition, it was assumed that the bonds formed once, remained relatively stable. One of the most amazing discoveries in the field of neuroscience, made in the last forty years, is that the synapses in reality very plastic. Many experts believe that the synaptic plasticity of the brain is the key to understanding the mechanisms of learning and memory.
Synapse and its functions
Synapse - a zone of contact between nerve cells or nerve cells and other entities (muscular, glandular tissue). The synapse consists of a presynaptic process belonging to the transmitter (afferent) neurons and postsynaptic components, which may be a dendrite, the body, or axon postsynaptic neuron, muscle, or secretory tissue. The synapses between nerve cells called interneurons bonds presynaptic terminals in the muscle or secretory fibers - motor plaque, and their complex - neuromuscular synapse or neurosecretory.
By way of the transfer of excitation synapses are divided into three groups. The first group includes the synapses, where the transfer of excitation by means of chemical transmitters (neurotransmitters), the second - with the transfer of excitation synapses due to the direct transfer of the electrical signal from the pre- to post-synaptic structures, the third - mixed synapses in which transmission It carried out both chemically and electrically.
The ability of synapses to the plasticity
Synapses - these are some of the most vulnerable components of plastic and neurons. The fact that for many synapses efficiency synapse-mediator interaction is not constant, it varies depending on the circumstances. This happens because the interneuronal contacts ripen unevenly, and this forms the basis for plastic changes interneuronal connections from a particular person as a result of education, training and so on.
There are short and long term synaptic plasticity, as well as potentiation and depression
Depression - a little more than a bad mood
(weakening).
Short-term synaptic plasticity lasts no longer than a few seconds, long - from several minutes to several hours or more.
Short-term plasticity is needed, for example, to adapt quickly to changes in the environment (due to this property of the brain you are very quickly removed his hand from the hot object), and short-term memory.
Long-term plasticity is responsible for the ability to remember. It is not clear for how long a person can store information because of this particular brain. Some experts believe that the person really does not forget anything - just some things that he, for some reason, can not remember. According to this theory, changes in synapses leave the specific changes in the brain and certain stimulation of memory, you can remove all that she had ever captured. To prove this, however, so far failed.
However, it is known that repeated exposure to a synapse strength of the synapse is increased for a prolonged period of time - thus brain stores important information. This phenomenon called long-term potentiation.
Synaptic plasticity of the brain and have direct synaptic connection not only of great importance for learning and memory, but also for the functioning of the nervous system. This area is still not well studied, but it is assumed that these properties of the brain are directly related to the development of disorders such as Parkinson's disease
Parkinson's disease - where the nerve endings are destroyed
Schizophrenia
Schizophrenia - to blame civilization
, Anxiety disorders and depression. Moreover, they participate in the development of alcohol, drug, and other dependencies. A better understanding of synaptic plasticity of the brain may contribute to significant advances in many areas of medicine.
Short-term and long-term synaptic activity
There are short-term forms of synaptic plasticity, which last seconds and minutes, as well as long-form, which extend hours, months and years. Durable types of plasticity are formed on the basis of short-term and underlie learning function of the nervous system.
Short-term synaptic plasticity - a change amount (increase or decrease, ie, depression) in presynaptic neurotransmitter connections, as well as an increase or decrease in the sensitivity of postsynaptic receptors to mediators. Depending on the severity of various processes for different types of active synapses is dominated either relief or depression of neurotransmitter secretion.
Based on the short forms of synaptic plasticity develops lasting form which may or may enhance or retard the conduction of impulses. These processes are especially active in brain regions responsible for memory - the hippocampus. Long form synaptic plasticity cause the growth and branching of the presynaptic nerve endings, a change in the number of receptors on the postsynaptic membrane, the formation of new synapses.
Synaptic activity - the basis of learning and memory
Long-term changes in the efficiency of synaptic transmission can be a mechanism for learning and memory. Plasticity is the foundation of learning, development and improvement. A newborn baby brain is much smaller than that of an adult, but over time the size of neurons in the brain are increased, and the nature of neural connections is complicated as the child's learning various skills. The development of the nervous system in the genes of man, but the training and experience contributes to this development the additions.
Synaptic plasticity of neurons and brain damage
As a result of stroke, injury, different diseases and poisonings can be lost a significant number of neurons. The property is plasticity of the brain to compensate for lost function in the defeat of one of its departments, other departments. This ability underlies the compensatory-adaptive reactions after diseases and brain damage.
Restoration of lost neurological function after stroke is associated with the ability of the brain to compensate for the structural and functional disorders. Currently, there are two main theories of neuroplasticity, explaining recover lost stroke
Stroke - a serious brain injury
Feature: injured cells take on the healthy cells and excitement is bypassing the lesion and excitement goes through the affected cells, which form new synaptic connections.
Scientific development of synaptic plasticity in the brain are important for learning and memory recovery and other functions of the brain after diseases.
Galina Romanenko
