Babinski reflex and corticospinal tract lesion
Babinski reflex and corticospinal tract lesion
Babinski reflex and corticospinal tract lesion
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Functions of the Ia inhibitory interneuronsThe Ia interneuron allows higher centers tocoordinate opposing muscles at ajoint through a single comm<strong>and</strong>.1) Mediates reciprocal innervation instretch <strong>reflex</strong> circuits.2) Receives input from corticaldescending pathway. A singledescending signal that activates oneset of muscles automatically leads torelaxation of the antagonists.3) Other descending pathway providesexcitatory or inhibitory connectionsto Ia neurons (I.e. greater inhibitionallowing con<strong>tract</strong>ion of opposingmuscles to occur).15Functions of the Renshaw Cells• inhibitory interneuron• Inputs: Excited by collaterals of the axons ofmotor neurons (leads to presynaptic inhibition);descending pathways•Effects:•Inhibition of large transient movements•Dis-inhibition of the antagonist muscle•Central modulation regulates the sensitivity ofMN to afferent input16