engleski

Afferent conditioning of motor evoked potentials following transcranial magnetic stimulation of primary motor cortex

Different types of stimuli (electric and vibration), targeting different afferent sources (cutaneous and muscle) have a range of effects on corticospinal excitability. Mostly the research has focused on effects of electrical stimulation of nerves, cutaneous and mixed, as well as effects of muscle vibration on modifications of magnetic motor evoked potentials (MEPs). Yet, little is known about the effect of cutaneous digit vibration stimuli on motor cortical excitability. The present study was designed to determine the time course of MEP modulation in hand muscle following cutaneous vibration of hand digit. In eleven healthy subjects, vibration at frequency of 120 Hz was applied to the index finger by means of electromagnetic solenoid- type of stimulation. The protocol consisted of control measurement and paired pulse paradigm where conditioning vibratory stimuli are applied to the digit followed by cortical single TMS pulse over the primary motor cortex at interstimuls intervals (ISIs) of 5-14 ms and of 18-500 ms in two experimental sessions. The results showed striking suppressive effect of MEP amplitudes at ISIs of 200, 300 and 400 ms. This period of late interval suppression is consistent with modifications in the cortical excitability suggested to be due to alterations in excitability of the motor cortex as a result of arrival of the antidromic sensory volley.

TMS ; MEP ; afferent conditioning ; vibration

nije evidentirano