02281nas a2200253   4500008004100000022001400041245007600055210006900131260001200200300001400212490000800226520146600234653001001700653002901710653001301739653001101752653002101763653002201784653004401806100002001850700002401870700002201894856011101916       2023                        eng d  a1432-110600aEffects of active and sham tDCS on the soleus H-reflex during standing.0 aEffects of active and sham tDCS on the soleus Hreflex during sta  c06/2023  a1611-16220 v2413 a<p>Weak transcranial direct current stimulation (tDCS) is known to affect corticospinal excitability and enhance motor skill acquisition, whereas its effects on spinal reflexes in actively contracting muscles are yet to be established. Thus, in this study, we examined the acute effects of Active and Sham tDCS on the soleus H-reflex during standing. In fourteen adults without known neurological conditions, the soleus H-reflex was repeatedly elicited at just above M-wave threshold throughout 30 min of Active (N = 7) or Sham (N = 7) 2-mA tDCS over the primary motor cortex in standing. The maximum H-reflex (H) and M-wave (M) were also measured before and immediately after 30 min of tDCS. The soleus H-reflex amplitudes became significantly larger (by 6%) ≈1 min into Active or Sham tDCS and gradually returned toward the pre-tDCS values, on average, within 15 min. With Active tDCS, the amplitude reduction from the initial increase appeared to occur more swiftly than with Sham tDCS. An acute temporary increase in the soleus H-reflex amplitude within the first minute of Active and Sham tDCS found in this study indicates a previously unreported effect of tDCS on the H-reflex excitability. The present study suggests that neurophysiological characterization of Sham tDCS effects is just as important as investigating Active tDCS effects in understanding and defining acute effects of tDCS on the excitability of spinal reflex pathways.</p>10aAdult10aEvoked Potentials, Motor10aH-Reflex10aHumans10aMuscle, Skeletal10aStanding Position10aTranscranial Direct Current Stimulation1 aMcCane, Lynn, M1 aWolpaw, Jonathan, R1 aThompson, Aiko, K  uhttps://neurotechcenter.org/publications/2023/effects-active-and-sham-tdcs-soleus-h-reflex-during-standing