Anticipatory reduction of the muscle activity associated with self-triggered electrical stimulation of mixed nerves and mecanical taps on muscle tendons.
Brief hammer taps self-imposed on the Achilles tendon or self-triggered electrical single-pulse stimulation delivered to the tibial nerve in the middle of the popliteal fossa are associated with an anticipatory reduction in the muscle activity (RMA) of the reflex-bearing soleus. The anticipatory RMA starts shortly prior tothe onset of the perturbation and lasts until the consequent T- or H-responses. When the amplitudes of the control T- and H-reflexes in a resting state are the same and equal to 50% of Hmax, then the anticipatory RMA patterns revealed with mechanical and electrical stimulation are similar. By selective skin stimulation in the medial region of the popliteal fossa (1.5-2.0 cm apart from the tibial nerve) with the same stimulus strength, the anticipatory RMA is significantly reduced. It is apparent that the main afferent sources for the elaboration of anticipatory RMA are the I afferents (presumably Ia afferents) and partly low threshold fast conducting cutaneous afferents.
Gerilovsky
L
L
Institute of Biophysics, Bulgarian Academy of Sciences, Sofia. gerilov@bio.bas.bg
Philipova
D
D
Struppler
A
A
D004558:Electric Stimulation; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D009132:Muscles / Q000502:physiology; D013979:Tibial Nerve / Q000502:physiology*