Extrapyramidal system

Extrapyramidal system is a set of anatomy, located in the big hemispheres, and the brain stem and participating in the implementation motor functions. The main part of the extrapyramidal system are the basal ganglia: caudate nucleus caudatus); lenticular nucleus lentiformis), which distinguish the external part - shell (putamen) and internal white ball (globus pallidus); red nucleus ruber); the black substance (substantia nigra); subthalamic nucleus Lewis (nucleus subthalamicus); medial nucleus of the optic hill (nucleus media] is thalami optici).
Basal ganglia have close ties with each other, visually hill, the cerebellum, the reticular formation of the trunk, the bark of the big hemispheres of a brain. Down the way from the extrapyramidal system go to the motor cells of the front horns spinal cord mainly in reticulo-spinal, rubro-spinal routes. Extrapyramidal system takes part in keeping the tone of the locomotor system, ensuring produktivnosti to movements, the regulation of involuntary automatic movements. On the phylogenetic, morphological and functional features of the basal ganglia can be divided into two parts: the new - neostriatum, which includes the caudate nucleus and the putamen, and more ancient - paleostriatum, which includes pale ball and black substance. At the first stages of a child's life prevails activity pale globe, resulting in involuntary, rhythmic movements of the newborn. With the development of neostriatum movement child become less chaotic, there are emotional manifestations (smile), the child begins to perform a number friendly and expressive movements.
Defeat ekstrapiramidna system often happens in infection and inherited degenerative diseases of the nervous system and is accompanied by changes in muscle tone and movements and the emotions of the patient. The defeat of the pale of the ball and the black substance is characterized hypertonic-hypokinetic syndrome or syndrome parkinsonizma (see). The defeat of the caudate nucleus and shell leads to hypotonic-hyperkinetic syndrome. The patient, there are different involuntary movements - hyperkinesia (see). Muscle tone is reduced.
Treatment depends on the cause of the disease; infectious nature of the disease is anti-inflammatory treatment.

Extrapyramidal system - many cellular education located in the big hemispheres, and the brain stem, performing complex motor-tonic function. To the extrapyramidal system include: caudate nucleus, lenticular nucleus ( see Basal nodes), medial nucleus of the optic hill, subthalamic nucleus Lewis, red kernel, black substance (see Middle brain), the nuclei of the hypothalamus (see), the cerebellum (see), vestibular nucleus, the lower Oliva (see the medulla and cortex (see)associated with striopallidarna system, a cerebellum and a red kernel. According to the structure, functions, and phylogeny caudate nucleus similar to the shell (striatum), pale ball (pallidum) - with a black substance (allegorically system). Pallidum - genetically older origin. Fish highest motor apparatus is pallidum, birds - the striatum, mammals - the cerebral cortex. In ontogenesis at the first stages pallidum does the bulk of the motor function (involuntary rhythmic movement of newborns). With the development of the striatum appear emotional manifestations (smile) and complicated statokinetic and tonic function (child holds his head, performs a friendly and expressive of movement). For pallidum characterized by the presence of large cells and a large number of nerve portages. Striatum is composed of small cells. In the striatum has somatotroponoe allocation: in Rostral part of the head, in the middle of the upper limb, and caudal appendage is the trunk and lower limbs. The major item that combines impulses in striopallidarna system, the cerebellum and other extrapyramidal formations, is the red nucleus, which goes way into the spinal cord to the cells of the anterior horn (rubrospinal path). Extrapyramidal system has a ring feedback, influencing the control of motor functions. From the bark of the big hemispheres impulses are in striopallidarna system, then through the optic hump back into the bark. The main feedback loop goes through the caudate nucleus to pale ball, then to the optic hill and from there to promotornoi cortex. Wider ring goes through striopallidarna system and the cerebellum.
Physiology. Extrapyramidal system responsible for the regulation of muscle tone, posture of the body and extremities, statokinetic and kinetic functions. This includes adapting to run the motor acts, flow of impulses to action, providing speed, rhythm, fluidity, flexibility movements. With muscle tone is inextricably linked posture of the body and extremities, adaptation poses to perform different movements and change poses during various motor actions. Extrapyramidal system participates in the implementation of expressive facial, supportive and friendly (synkinesia walking) movements, gestures and automated motor acts (grimaces, whistles and others), emotional manifestations (laughter, crying others).

electromyogram in Parkinson
Fig. 1. Electromyogram in parkinsonism.
akinetic-rigid syndrome
Fig. 2. Akinetic-rigid syndrome.


Pathology. Pathological syndromes occur with the defeat of nuclei and their relationships. The detection of pathology of the extrapyramidal system help of special methods of registration of bioelectric activity of muscles (Fig. 1), myotonometry, termografia, kymography hyperkinesia alone and if irritation occurs. With the defeat ekstrapiramidna system violated motor function, muscle tone, posture, body, emotional manifestations, vasomotor reactions. Violations accompanied by an excess of movements and positions are shown by hyperkinesia (see), excessive body language, sententiae (see); violations deficit movements akinesis. Akinetic-rigid (allegorically) syndrome (Fig. 2) shows akinesis, plastic hypertension muscle phenomenon gears, trembling type "Catania pills", flexor the position of head and body, a mask-like appearance of the face, unmodulated speech, lack of emotional expression. The beginning of voluntary movements difficult, disappear auxiliary movement when standing up and walking (characins); gait small steps with a retro, latero - or propulsive; improve postural reflexes (see) Westphal and Tavener-Foy, the tendency to catalepsy. Akinetic-rigid syndrome occurs when encephalitis, poisoning by carbon monoxide, manganese, mercury, lead, with atherosclerosis defeat cortex, in progressive lesions allianoi system (Parkinson's disease, atherosclerotic muscle rigidity Forster). Hyperkinetic is hypotonic (veins) syndrome is characterized by abnormal movements, artsy postures, grimaces, enhanced body language, hyperemia, it is jerky, handwriting loping gait big, irregular steps. If hypotension muscle observed tonic knee-jerk Gordon (freezing tibia in a reclined position).

koreizskiy hyperkinesis
Fig. 3. Koreizskiy hyperkinesis.

With the defeat ekstrapiramidna system is observed tremor, different in nature, frequency and rhythm, according to the term of manifestations (permanent or paroxysmal jitter), depending on a variety of stimuli (emotional excitation, nociceptive and proprioceptive irritation), localization (in the fingers, hand, arm, leg, head and others). Intentsionnogo jitter, manifested during the movement, occurs when damage to the cerebellum and its connections. Koreatissa hyperkinesia arise in connection with the defeat of small cells veins of the system. When trochaic (see) are fast arrhythmic non-localized excess of motion in the muscles of the face, tongue, legs, torso, neck (for example, when small trochaic of Sidengama, trochaic Gentington, trochaic pregnant). Hemichorea - sided koreizskiy hyperkinesis (Fig. 3) can be observed and disorders of cerebral circulation. Khoreiversky hyperkinesis in combination with a change in the psyche meets with trochaic Gentington. Paroxysmal khoreiversky rurally hyperkinesis is characterized by the participation in movements of all the limbs, manifested in the form of hacking, sweeping movements in extremities with the rotation of the torso, head and all four limbs. Hemiballismus - hyperkinesia, manifested fast rotational throwing movements in the hand and the leg the same side in combination with hypotension muscles, is observed with the defeat of the kernel Lewis and his relationships. Swinging swinging movement (like the sweep of the wings of birds), combined with hyperkinesis speech muscles, are observed at hepato-lenticular degeneration (see)when are mainly affected lenticular nucleus. When choreoathetosis (the defeat of stri-pallidum) observed koreatissa and atleticheskaja movement. The destruction of large cells striped body causes atetoz (see), which is characterized by slow worm-like movements of the fingers and hands (Fig. 4), at least in the foot. For bilateral acetosa is characterized by involvement in hyperkinesis of both legs.

atleticheskaja hyperkinesis
Fig. 4. Atleticheskaja hyperkinesis fingers and hand.

Psevdomatematicheskoe hyperkinesia extremities occur in violation of deep sensitivity to paralyzed limbs. Giperbolicheskie (thalamo veins) hyperkinesia in paretic limbs consist of Shebalino-extention movements in the leg, then in his hand and occur in response to nociceptive stimuli, which is applied in the area of hyperpathia. When veins syndrome can occur Tiki facial muscles of the abdominal wall. Tick diaphragmatic muscles causing hiccups. The hyperkinesia with respiratory paroxysms result of the contraction of the muscles of the diaphragm, the anterior abdominal wall and are characterized by bouts of rapid convulsive breaths, accompanied by crying, coughing, hyperkinesias of the abdominal muscles, stress diaphragm. During the paroxysmal respiratory hyperkinesis a rush, there are vasomotor disorders. Myoclonic twitches combined with epileptic seizures (myoclonus epilepsy of Unterricht - Lundborg). Symmetric clonic jerking abdominal muscles, back muscles of the hip, the quadriceps muscles that appear sporadically (10-15 minutes), observed in pernicieuse's ataxia. Tonic contraction of the muscles of the face (facial parashas) are bilateral, amplified by excitement. Torsion spasm characterized the tonic note of the muscles of the body and neck (Fig. 5)increasing when walking; rotary movement of the limbs and trunk thus cause a violation of the gait, speech, swallowing.

torsion spasm
Fig. 5. Torsion spasm.

With the defeat ekstrapiramidna system often found tonic spasm of sight, blepharospasm, uncontrollable fits of laughter, crying.
Complex paroxysmal hyperkinesia with tonic flexor-adduktoren movements of the limbs occur in defeat ekstrapiramidna system during violent weeping; they occur cycle (2-3 minutes) in the form of mahonia hand the face, rhythmic potiranie the heart, face (N. K. Bogolepov). Kind of extrapyramidal syndrome is subcortical epilepsy.
Surgical intervention on pallidum or ventrolateral the nucleus of the thalamus in parkinsonizme (see) have shown that the destruction of one of these entities is terminated tremors and stiffness. Neuropharmacological funds tropinovogo number (arcan) can suppress the hyperkinesia and affect muscle tone in extrapiramidale disorders.