@article{ref1,
title="Startle stimuli exert opposite effects on human cortical and spinal motor system excitability in leg muscles",
journal="Physiological research",
year="2011",
author="Ilic, T. V. and Pötter-Nerger, M. and Holler, I. and Siebner, H. R. and Ilic, N. V. and Deuschl, G. and Volkmann, J.",
volume="60",
number="Suppl 1",
pages="S101-6",
abstract="Increased excitability of the spinal motor system has been observed after loud and unexpected acoustic stimuli (AS) preceding H-reflexes. The paradigm has been proposed as an electrophysiological marker of reticulospinal tract activity in humans. The brainstem reticular formation also maintains dense anatomical interconnections with the cortical motor system. When a startling AS is delivered, prior to transcranial magnetic stimulation (TMS), the AS produces a suppression of motor evoked potential (MEP) amplitude in hand and arm muscles of healthy subjects. Here we analyzed the conditioning effect of a startling AS on MEP amplitude evoked by TMS to the primary motor leg area. Ten healthy volunteers participated in two experiments that used a conditioning-test paradigm. In the first experiment, a startling AS preceded a suprathreshold transcranial test stimulus. The interstimulus interval (ISI) varied between 20 to 160 ms. When given alone, the test stimulus evoked a MEP amplitude of approximately 0.5 mV in the slightly preinervated soleus muscle (SOL). In the second experiment, the startling AS was used to condition the size of the H-reflex in SOL muscle. Mean MEP amplitude was calculated for each ISI. The conditioning AS suppressed MEP amplitude at ISIs of 30-80 ms. By contrast, H-reflex amplitude was augmented at ISIs of 100-200 ms. Acoustic stimulation exerts opposite and ISI-specific effects on the amplitude of MEPs and H-reflex in the SOL muscle, indicating different mechanism of auditory-to-motor interactions at cortical and spinal level of motor system.<p /><p>Language: en</p>",
language="en",
issn="0862-8408",
doi="",
url="http://dx.doi.org/"
}