Properties of the nerve centers. 

Nerve centers have some common properties, which is largely determined by the structure and function sinaptich e Sgiach formations.

1. Unilateral excitation. In the central nervous system – in its nerve tse n bang inside reflex arc and neuronal excitation circuits as straight as a rule, is in one direction – from the presynaptic membrane to the pos t synaptic, t.   e.  along the reflex arc from the afferent to efferent neuron. This property is associated with the properties of synapses.

2. Slowing of excitation in the nerve centers or tse n sweeping delay. Deceleration of excitation of nerve tse n tram was called the central delay. It is caused SLOW n nym conduct nerve impulses through the synapse, as spent t Xia time following mediator release from presynaptic carrying and molecules, its release into the synaptic cleft and the generation of the exciting pos t synaptic potential (EPSP).

3. Summation of arousal and summation of inhibition. It is customary to distinguish two types of summation — temporal and spatial. Temporary or n about therefore summation manifested in the fact that in the region postsinapt and cal membrane occurs summation traces of excitation time, t.   e.   on the neuron in the region of its axon mound, events occur, which play out in separate sections of the neuron membrane at a certain interval of time. Spatial summation in the summation field is shown on the neuron axon hillock postsinapt and iCal potentials that occur simultaneously in the different parts Kah this neuron in response to come from other neurons action potentials. Even if each of the neurons separately causes only subliminal EPSP, when they appear simultaneously, they will be able to bring the membrane potential in the axonal knoll of the neuron to a critical level of depolarization and thereby cause neuron excitation. All this fully applies to the phenomenon of summation of inhibition.

4. The phenomenon of occlusion (or blockage) reflects the effect of the interaction between a two pulse flows, which occurs when interac m Noe suppression of reflex responses. Total response (D p lex) caused by the simultaneous action of the two streams is less than the sum of two reactions that occur under the action of each of the two streams separately. According C. Sherrington, the phenomenon of occlusion b yasnyaetsya synaptic overlapping fields formed by two interacting functioning afferent reflexes.

5. The phenomenon of relief, which, in its external manifestation , is opposed to occlusion. 0no manifested in the fact that the joint irritation and zhenii receptive fields of the two reflexes ReA has been increasing to the tions of the body to the action of the two stimuli simultaneously.

6. Transformation of the rhythm of arousal. This is one of the properties as a neuron circuit of the neural component which is detected during etc. of reference excitation of neural circuits. Rhythm transformation excitaton Well Denia is the ability of a neuron to change the rhythm of coming and m pulses. It manifests itself in the opposite phenomenon – the frequency of pr and the impulses going to the neuron is higher than the frequency of generation of AP when the neuron responds to these impulses.

7. Aftermath. This is one of the properties characteristic of neural circuits. It consists in the fact that the reaction of a neuron (in the form of generation of od and night PDs or packets of PD) to a pulse that arrives at it lasts a long time. At the heart of this surprising effect, as assumption and gayut, two mechanisms are. The first is associated with the presence of a long-term EPSP that arises in response to the impulse that arrives at the neuron (a similar c and tuition is also characteristic of the phenomenon of transformation of the rhythm of arousal). H e rarely a phenomenon called facilitation (simplification). Second fur and nism associated with the presence in the CNS peculiar “excitation traps”, which occurs long (in minutes or n e how many hours) circulation of the flow of pulses, called the reverberation of nerve impulses.

8. High fatigue of the nerve centers. This property is characteristic of neural circuits, including reflex arcs. With one sided of us, it is shown that in the neural connections, as in many other about of link systems may develop fatigue, which manifests itself in a gradual decrease (up to complete cessation) reflex response during prolonged stimulation of afferent neurons.

9. The tone of the nerve centers. For many neural associations, or nerve centers, background activity is characteristic, t.   e.   generation of nerve impulses with a certain frequency for a long time. Such activity is not due to the presence in the composition of this association neuron- peysmkera (fonovoaktivnogo neuron), and constant excited e Niemi afferent neuron through continuous irritation ce n weed receptors. Tone nerve centers and ensures a constant m pulsation to the corresponding peripheral systems as well as the post of yannoe intercentral interaction.

10. Plasticity of the nerve centers – it is their ability to rearrange the first functional properties ke and, to a certain extent, functions under the influence of long-term external effects or focal povrezhd e brain niyah. Posttraumatic plasticity of neural associations performs a compensatory (replacement) function, plasti h Nosta caused long afferent stimulation – to adapt and negative function. For example, for the process of learning plasticity is not the first ronnyh of Kommersant unity is a prerequisite, that is.   e.   its working mechanism. In general, due to the plasticity property, the nerve center can significantly modify the course of reflex reactions. On a novnym Fundam a cop, which allows to realize plasticity property is obviously considered to be the presence of each neuron of individually g Romney of synaptic connections, and the possibility of changes in B n thetic processes within each neuron.

local_offerevent_note May 16, 2019

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