TY - JOUR
T1 - Cortical and subcortical effects of transcutaneous spinal cord stimulation in humans with tetraplegia
AU - Benavides, Francisco D.
AU - Jo, Hang Jin
AU - Lundell, Henrik
AU - Edgerton, V. Reggie
AU - Gerasimenko, Yuri
AU - Perez, Monica A.
PY - 2020/3/25
Y1 - 2020/3/25
N2 - An increasing number of studies supports the view that transcutaneous electrical stimulation of the spinal cord (TESS) promotes functional recovery in humans with spinal cord injury (SCI). However, the neural mechanisms contributing to these effects remain poorly understood. Here we examined motor-evoked potentials in arm muscles elicited by cortical and subcortical stimulation of corticospinal axons before and after 20 min of TESS (30 Hz pulses with a 5 kHz carrier frequency) and sham-TESS applied between C5 and C6 spinous processes in males and females with and without chronic incomplete cervical SCI. The amplitude of subcortical, but not cortical, motorevoked potentials increased in proximal and distal arm muscles for 75 min after TESS, but not sham-TESS, in control subjects and SCI participants, suggesting a subcortical origin for these effects. Intracortical inhibition, elicited by paired stimuli, increased after TESS in both groups. When TESS was applied without the 5 kHz carrier frequency both subcortical and cortical motor-evoked potentials were facilitated without changing intracortical inhibition, suggesting that the 5 kHz carrier frequency contributed to the cortical inhibitory effects. Hand and arm function improved largely when TESS was used with, compared with without, the 5 kHz carrier frequency. These novel observations demonstrate that TESS influences cortical and spinal networks, having an excitatory effect at the spinal level and an inhibitory effect at the cortical level. We hypothesized that these parallel effects contribute to further the recovery of limb function following SCI.
AB - An increasing number of studies supports the view that transcutaneous electrical stimulation of the spinal cord (TESS) promotes functional recovery in humans with spinal cord injury (SCI). However, the neural mechanisms contributing to these effects remain poorly understood. Here we examined motor-evoked potentials in arm muscles elicited by cortical and subcortical stimulation of corticospinal axons before and after 20 min of TESS (30 Hz pulses with a 5 kHz carrier frequency) and sham-TESS applied between C5 and C6 spinous processes in males and females with and without chronic incomplete cervical SCI. The amplitude of subcortical, but not cortical, motorevoked potentials increased in proximal and distal arm muscles for 75 min after TESS, but not sham-TESS, in control subjects and SCI participants, suggesting a subcortical origin for these effects. Intracortical inhibition, elicited by paired stimuli, increased after TESS in both groups. When TESS was applied without the 5 kHz carrier frequency both subcortical and cortical motor-evoked potentials were facilitated without changing intracortical inhibition, suggesting that the 5 kHz carrier frequency contributed to the cortical inhibitory effects. Hand and arm function improved largely when TESS was used with, compared with without, the 5 kHz carrier frequency. These novel observations demonstrate that TESS influences cortical and spinal networks, having an excitatory effect at the spinal level and an inhibitory effect at the cortical level. We hypothesized that these parallel effects contribute to further the recovery of limb function following SCI.
KW - Corticospinal
KW - Intracortical inhibition
KW - Neurophysiology
KW - Neuroplasticity
KW - Spinal cord injury
KW - Spinal networks
UR - http://www.scopus.com/inward/record.url?scp=85082542540&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85082542540&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.2374-19.2020
DO - 10.1523/JNEUROSCI.2374-19.2020
M3 - Article
C2 - 31996455
AN - SCOPUS:85082542540
VL - 40
SP - 2633
EP - 2643
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 13
ER -