ABSTRACT
The aim of this study was to establish the effects of transcutaneous spinal cord (transspinal) stimulation over the cervical region on soleus H-reflex excitability in healthy subjects while at rest. Reflex effects were established at subthreshold and suprathreshold cervical transspinal conditioning stimulation intensities of the extensor carpi radialis transspinal evoked potential. Twenty soleus H-reflexes at 0.125â¯Hz were recorded randomly under control conditions and following transspinal conditioning stimulation at conditioning-test intervals that ranged from 0 to 55â¯ms and tested in increment of 5â¯ms steps and at 100â¯ms. Cervical transspinal stimulation at suprathreshold and not at subthreshold intensities produced short, medium, and long-latency soleus H-reflex facilitation. The observed facilitatory reflex effects are consistent with activation of excitatory components of long propriospinal neurons. We propose the use of cervical transspinal stimulation to potentiate excitatory neuronal interactions between arms and legs in neurological disorders.
