Driving system extrapyramidal

The driving system extrapyramidal indicates the circuits Nerveux responsible for the involuntary Motricité, in particular Réflexe, and of the control of the Posture. With the difference of the pyramidal driving system, it is not a question of an entity unit Anatomique but rather a functional whole of relatively slow transmission channels because the information which circulates since the Cerveau until the Spinal-cord passes by various relays which allow a multitude of Rétrocontrôle S on the driving order. It is thus said that they are polysynaptic ways because they bring into play several Neuron S between the driving Cortex and the effector Muscle and thus several Synapse S.

The driving system extrapyramidal consists of three principal beams:

the Faisceau rubrospinal, which leaves the red Noyau and follows a way parallel with the side Faisceau corticospinal, intervenes in the motricity and the coordination of large the distal Muscle S of the lower and higher members. The red core does not receive any afférence of the system of the ganglia of the base and is related to the cérébelleux system
the Faisceau vestibulospinal is implied in the control of the balance
the Faisceau réticulospinal plays a part in the Muscular tone, the Marche or the adjustments postural automatic.

Historical anecdote

Contrary to the use, unsuitable, that it is made of the expression way extrapyramidale , there is no strictly speaking neuroanatomical entity which corresponds to this terminology. The concept was due to the English doctor Kinnier Wilson (1878-1937) which thought, in 1912, that in addition of the pyramidal Faisceau there were driving beams in parallel. Wilson was armature in error by the fact that the beam which is in fact pallido - Thalamique descended in the cerebral Tronc and the Spinal-cord. It should be said that the brutal plicature of the fields of Forel had what to mislead. Nevertheless, the contemporary Neurosciences did not give up the idea of a driving system extrapyramidal as a functional entity. Moreover, the description of the Syndrome extrapyramidal of Wilson remains very useful in clinical.

See too

Random links: