1. Paired-associative stimulation can modulate muscle fatigue induced motor cortex excitability changes
- Author
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Milos Ljubisavljevic, Suzana Blesic, Subramanian Dhanasekaran, Sladjan Milanovic, Tihomir V. Ilić, and Saša R. Filipović
- Subjects
Adult ,Male ,medicine.medical_treatment ,Central nervous system ,Stimulation ,050105 experimental psychology ,03 medical and health sciences ,Behavioral Neuroscience ,0302 clinical medicine ,Neuroplasticity ,medicine ,Humans ,0501 psychology and cognitive sciences ,Peripheral Nerves ,Paired associative stimulation ,Muscle fatigue ,Brain plasticity ,Neuronal Plasticity ,Electromyography ,Interstimulus interval ,05 social sciences ,Motor Cortex ,Long-term potentiation ,Evoked Potentials, Motor ,Transcranial Magnetic Stimulation ,Electric Stimulation ,Transcranial magnetic stimulation ,medicine.anatomical_structure ,Thumb ,TMS ,Muscle Fatigue ,Motor cortex ,Female ,sense organs ,Psychology ,Neuroscience ,030217 neurology & neurosurgery - Abstract
The aim of this study was to examine whether the changes of the motor cortex excitability induced by muscle fatigue could be affected by prior or subsequent intervention protocol supposed to induce opposing excitability changes. For this purpose we used paired associative stimulation (PAS) method, where peripheral nerve stimuli were associated with transcranial magnetic stimulation (TMS) of the motor cortex at a fixed interstimulus interval of 25 ms. The PAS protocol used is known to produce a long lasting, long-term potentiation (LTP) like change of cortical plasticity manifested by significant increase in motor evoked potentials (MEPs) amplitude. In this study, we confirmed significant MEP size reduction following fatigue, which had been already reported in the literature. When PAS was applied either immediately before or after muscle fatigue protocol, the excitability changes were largely occluded and MEP sizes remained close to baseline levels. However, in spite of the effects on cortical excitability, conditioning with PAS did not cause any change in target fatigue measure, the endurance point, which remained the same as when fatiguing protocol was applied alone. The present results demonstrate that fatigue-related changes in cortical excitability can be modulated by either prior or subsequent excitability promoting activity. They also suggest that muscle fatigue associated changes in motor cortical excitability probably represent non-specific activity-related plasticity, rather than a direct expression of the so-called central fatigue.
- Published
- 2011