Summary
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1.
Electrical stimulation of extensor nerves of the ankle has been used to investigate the presynaptic inhibition in a synergic monosynaptic reflex arc.
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2.
Depression of monosynaptic reflex response as well as increase in excitability of Ia afferent terminals in the MG (medial gastrocnemius) reflex arc is found following the conditioning stimulation of LGS (lateral gastrocnemius-soleus) nerve at Group I strength.
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3.
Excitability increase of the Ia terminals of the LGS nerve is also found following the conditioning stimulation of either a group of fibres of the same nerve or the MG nerve.
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4.
Conditioning by Group I afferent volleys from either the LGS or the PBST (posterior biceps-semitendinosus) muscles produces comparable changes in excitability of the Ia terminals from MG muscle.
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5.
The hypothesis is advanced that the depression of the monosynaptic reflex discharge during repetitive stimulation is mainly caused by the depolarization of the Ia afferent terminals, i.e. by presynaptic inhibition.
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Decandia, M., Provini, L. & Táboříková, H. Presynaptic inhibition of the monosynaptic reflex following the stimulation of nerves to extensor muscles of the ankle. Exp Brain Res 4, 34–42 (1967). https://doi.org/10.1007/BF00235215
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DOI: https://doi.org/10.1007/BF00235215