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Sub-threshold spinal cord stimulation facilitates spontaneous motor activity in spinal rats.

Gad P, Choe J, Shah P, Garcia-Alias G, Rath M, Gerasimenko Y, Zhong H, Roy RR, Edgerton VR - J Neuroeng Rehabil (2013)

Bottom Line: Spontaneous cage activity was recorded using a specially designed swivel connector to record EMG signals and an IR based camcorder to record video.In contrast, with eEmc the rats were highly active and the hindlimbs showed robust alternating flexion and extension resulting in step-like movements during forelimb-facilitated locomotion and often would stand using the sides of the cages as support.The mean and summed integrated EMG levels in both a hindlimb flexor and extensor muscle were higher with than without eEmc.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles, Terasaki Life Sciences Building, 610 Charles E, Young Drive East, Los Angeles, CA 90095-7239, USA. vre@ucla.edu.

ABSTRACT

Background: Epidural stimulation of the spinal cord can be used to enable stepping on a treadmill (electrical enabling motor control, eEmc) after a complete mid-thoracic spinal cord transection in adult rats. Herein we have studied the effects of eEmc using a sub-threshold intensity of stimulation combined with spontaneous load-bearing proprioception to facilitate hindlimb stepping and standing during daily cage activity in paralyzed rats.

Methods: We hypothesized that eEmc combined with spontaneous cage activity would greatly increase the frequency and level of activation of the locomotor circuits in paralyzed rats. Spontaneous cage activity was recorded using a specially designed swivel connector to record EMG signals and an IR based camcorder to record video.

Results and conclusion: The spinal rats initially were very lethargic in their cages showing little movement. Without eEmc, the rats remained rather inactive with the torso rarely being elevated from the cage floor. When the rats used their forelimbs to move, the hindlimbs were extended and dragged behind with little or no flexion. In contrast, with eEmc the rats were highly active and the hindlimbs showed robust alternating flexion and extension resulting in step-like movements during forelimb-facilitated locomotion and often would stand using the sides of the cages as support. The mean and summed integrated EMG levels in both a hindlimb flexor and extensor muscle were higher with than without eEmc. These data suggest that eEmc, in combination with the associated proprioceptive input, can modulate the spinal networks to significantly amplify the amount and robustness of spontaneous motor activity in paralyzed rats.

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Average integrated EMG with and without eEmc. Mean (±SEM) frequency of occurrence of different ranges of integrated EMG amplitudes with and without eEmc during the 6-hr recording period of cage activity expressed in one-min bins.
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Figure 5: Average integrated EMG with and without eEmc. Mean (±SEM) frequency of occurrence of different ranges of integrated EMG amplitudes with and without eEmc during the 6-hr recording period of cage activity expressed in one-min bins.

Mentions: There was a larger number of one-min bins with relatively high levels of integrated EMG activity with than without eEmc distributed across the 6-hr recording period for both the TA and soleus (Figure 4). Differences in the frequency distributions of EMG amplitudes with and without eEmc also were evident (Figure 5). Higher EMG amplitudes were observed more frequently in both the TA and soleus in the presence of eEmc. There was greater evidence of reciprocal coordination between the TA and soleus muscles with than without eEmc across the 6-hr recording period (Figure 6A). The level of EMG amplitude modulation was greater in the TA than the soleus and with this increased occurrence of higher amplitudes in the TA there was clearly a higher incidence of co-contraction between the TA and soleus muscles without eEmc. In addition, instances showing apparent reciprocal activity without eEmc had fewer and less robust alternating patterns (Figure 6B I) compared to those observed with eEmc (Figure 6B II).


Sub-threshold spinal cord stimulation facilitates spontaneous motor activity in spinal rats.

Gad P, Choe J, Shah P, Garcia-Alias G, Rath M, Gerasimenko Y, Zhong H, Roy RR, Edgerton VR - J Neuroeng Rehabil (2013)

Average integrated EMG with and without eEmc. Mean (±SEM) frequency of occurrence of different ranges of integrated EMG amplitudes with and without eEmc during the 6-hr recording period of cage activity expressed in one-min bins.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016220&req=5

Figure 5: Average integrated EMG with and without eEmc. Mean (±SEM) frequency of occurrence of different ranges of integrated EMG amplitudes with and without eEmc during the 6-hr recording period of cage activity expressed in one-min bins.
Mentions: There was a larger number of one-min bins with relatively high levels of integrated EMG activity with than without eEmc distributed across the 6-hr recording period for both the TA and soleus (Figure 4). Differences in the frequency distributions of EMG amplitudes with and without eEmc also were evident (Figure 5). Higher EMG amplitudes were observed more frequently in both the TA and soleus in the presence of eEmc. There was greater evidence of reciprocal coordination between the TA and soleus muscles with than without eEmc across the 6-hr recording period (Figure 6A). The level of EMG amplitude modulation was greater in the TA than the soleus and with this increased occurrence of higher amplitudes in the TA there was clearly a higher incidence of co-contraction between the TA and soleus muscles without eEmc. In addition, instances showing apparent reciprocal activity without eEmc had fewer and less robust alternating patterns (Figure 6B I) compared to those observed with eEmc (Figure 6B II).

Bottom Line: Spontaneous cage activity was recorded using a specially designed swivel connector to record EMG signals and an IR based camcorder to record video.In contrast, with eEmc the rats were highly active and the hindlimbs showed robust alternating flexion and extension resulting in step-like movements during forelimb-facilitated locomotion and often would stand using the sides of the cages as support.The mean and summed integrated EMG levels in both a hindlimb flexor and extensor muscle were higher with than without eEmc.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles, Terasaki Life Sciences Building, 610 Charles E, Young Drive East, Los Angeles, CA 90095-7239, USA. vre@ucla.edu.

ABSTRACT

Background: Epidural stimulation of the spinal cord can be used to enable stepping on a treadmill (electrical enabling motor control, eEmc) after a complete mid-thoracic spinal cord transection in adult rats. Herein we have studied the effects of eEmc using a sub-threshold intensity of stimulation combined with spontaneous load-bearing proprioception to facilitate hindlimb stepping and standing during daily cage activity in paralyzed rats.

Methods: We hypothesized that eEmc combined with spontaneous cage activity would greatly increase the frequency and level of activation of the locomotor circuits in paralyzed rats. Spontaneous cage activity was recorded using a specially designed swivel connector to record EMG signals and an IR based camcorder to record video.

Results and conclusion: The spinal rats initially were very lethargic in their cages showing little movement. Without eEmc, the rats remained rather inactive with the torso rarely being elevated from the cage floor. When the rats used their forelimbs to move, the hindlimbs were extended and dragged behind with little or no flexion. In contrast, with eEmc the rats were highly active and the hindlimbs showed robust alternating flexion and extension resulting in step-like movements during forelimb-facilitated locomotion and often would stand using the sides of the cages as support. The mean and summed integrated EMG levels in both a hindlimb flexor and extensor muscle were higher with than without eEmc. These data suggest that eEmc, in combination with the associated proprioceptive input, can modulate the spinal networks to significantly amplify the amount and robustness of spontaneous motor activity in paralyzed rats.

Show MeSH
Related in: MedlinePlus