Effects of trains of high-frequency stimulation of the premotor/supplementary motor area on conditioned corticomotor responses in hemicerebellectomized rats

摘要: We studied the effects of low- and high-frequency premotor electrical stimulations on conditioned corticomotor responses, intra-cortical facilitation (ICF) spinal excitability in hemicerebellectomized rats (left side). Trains stimulation were applied prefrontal region rFr2 (the equivalent premotor/supplementary motor area primates) at a rate 1 Hz (low-frequency LFS) or 20 (high-frequency HFS). Test stimuli cortex preceded by conditioning stimulus contralateral sciatic nerve (two inter-stimulus intervals ISIs studied: 5 ms 45 ms). (A) At ISI-5, increased amplitudes MEPs (motor evoked potentials) left cortex. This afferent was enhanced if trains administered over ipsilateral area, HFS had higher than LFS. The lower for right cortex, both LFS HFS. (B) ISI-45, responses depressed as compared to unconditioned (afferent inhibition). Following LFS, degree inhibition unchanged while it with baseline, Interestingly, decreased significantly following (C) ICF but similarly sides LFS/HFS. These results (1) confirm contralaterally hemicerebellar ablation, (2) demonstrate first time that cerebellum is necessary tuning peripheral stimulation, (3) show application does not cancel defect short ISIs, (4) suggest longer could have interesting properties modulation case extensive cerebellar lesion. Our study underlines ablation impacts efficacy combined peripheral-motor an ISI-dependent manner.