scholarly journals Intraspinal microstimulation and diaphragm activation after cervical spinal cord injury

2017 ◽  
Vol 117 (2) ◽  
pp. 767-776 ◽  
Author(s):  
L. M. Mercier ◽  
E. J. Gonzalez-Rothi ◽  
K. A. Streeter ◽  
S. S. Posgai ◽  
A. S. Poirier ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spinal Cord ◽  
Emg Activity ◽  
Motor Nucleus ◽  
Adult Rats ◽  
Intraspinal Microstimulation ◽  
Emg Signal ◽  
Cord Injury ◽  
Diaphragm Activity

Intraspinal microstimulation (ISMS) using implanted electrodes can evoke locomotor movements after spinal cord injury (SCI) but has not been explored in the context of respiratory motor output. An advantage over epidural and direct muscle stimulation is the potential of ISMS to selectively stimulate components of the spinal respiratory network. The present study tested the hypothesis that medullary respiratory activity could be used to trigger midcervical ISMS and diaphragm motor unit activation in rats with cervical SCI. Studies were conducted after acute (hours) and subacute (5–21 days) C2 hemisection (C2Hx) injury in adult rats. Inspiratory bursting in the genioglossus (tongue) muscle was used to trigger a 250-ms train stimulus (100 Hz, 100–200 μA) to the ventral C4 spinal cord, targeting the phrenic motor nucleus. After both acute and subacute injury, genioglossus EMG activity effectively triggered ISMS and activated diaphragm motor units during the inspiratory phase. The ISMS paradigm also evoked short-term potentiation of spontaneous inspiratory activity in the previously paralyzed hemidiaphragm (i.e., bursting persisting beyond the stimulus period) in ∼70% of the C2Hx animals. We conclude that medullary inspiratory output can be used to trigger cervical ISMS and diaphragm activity after SCI. Further refinement of this method may enable “closed-loop-like” ISMS approaches to sustain ventilation after severe SCI. NEW & NOTEWORTHY We examined the feasibility of using intraspinal microstimulation (ISMS) of the cervical spinal cord to evoke diaphragm activity ipsilateral to acute and subacute hemisection of the upper cervical spinal cord of the rat. This proof-of-concept study demonstrated the efficacy of diaphragm activation, using an upper airway respiratory EMG signal to trigger ISMS at the level of the ipsilesional phrenic nucleus during acute and advanced postinjury intervals.

scholarly journals Laryngeal and swallow dysregulation following acute cervical spinal cord injury

2021 ◽  
Author(s):  
Teresa Pitts ◽  
Kimberly E Iceman ◽  
Alyssa Huff ◽  
M Nicholas Musselwhite ◽  
Michael L Frazure ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spinal Cord ◽  
Upper Airway ◽  
Emg Activity ◽  
Post Injury ◽  
Percent Change ◽  
Cord Injury ◽  
Posterior Cricoarytenoid ◽  
Diaphragm Activity

Proper function of the larynx is vital to airway protection, including swallow. While the swallow reflex is controlled by the brainstem, patients with cervical spinal cord injuries (cSCI) are likely at increased risk of disordered swallow (dysphagia) and pneumonia, and the underlying mechanisms are unknown. We aimed to determine if acute spinal cord injury would disrupt swallow function in animal models. We hypothesized that 1) loss of descending efferent information to the diaphragm would affect swallow and breathing differently, and that 2) loss of ascending spinal afferent information would alter central swallow regulation to change motor drive to the upper airway. We recorded amplitudes of laryngeal and inspiratory muscle electromyograms (EMGs), submental and pharyngeal muscle EMGs, and cardiorespiratory measures in freely breathing pentobarbital-anesthetized cats and rats. First, we assessed the effect of a lateral hemisection at the second cervical level (C2) in cats during breathing. Posterior cricoarytenoid (laryngeal abductor) EMG activity during inspiration increased nearly two-fold, indicating that inspiratory laryngeal drive increased following cSCI. Ipsilateral to the injury, the crural diaphragm EMG was significantly reduced during breathing (62 ± 25 percent change post-injury), but no animal had a complete termination of all activity; 75% of animals had an increase in contralateral diaphragm recruitment after cSCI, but this did not reach significance. Next, we assessed the effect of C2 lateral hemisection in cats during swallow. The thyroarytenoid (laryngeal adductor) and thyropharyngeus (pharyngeal constrictor) both increased EMG activity during swallow, indicating increased upper airway drive during swallow following cSCI. There was no change in the number of swallows stimulated per trial. We also found that diaphragm activity during swallow (schluckatmung) was bilaterally suppressed after lateral C2 hemisection, which was unexpected because this injury did not suppress contralateral diaphragm activity during breathing. Swallow-breathing coordination was also affected by cSCI, with more post-injury swallows occurring during early expiration. Finally, because we wanted to determine if the chest wall is a major source of feedback for laryngeal regulation, we performed T1 total transections in rats. As in the cat C2 lateral hemisection, a similar increase in inspiratory laryngeal activity (posterior cricoarytenoid) was the first feature noted after rat T1 complete spinal cord transection. In contrast to the cat C2 lateral hemisection, diaphragmatic respiratory drive increased after T1 transection in every rat (215 ± 63 percent change), and this effect was significant. Overall, we found that spinal cord injury alters laryngeal drive during swallow and breathing, and alters swallow-related diaphragm activity. Our results show behavior-specific effects, suggesting that swallow may be more affected than breathing is by cSCI, and emphasizing the need for additional studies on laryngeal function during breathing and swallow after spinal cord injury.

scholarly journals Spinal Interneurons and Forelimb Plasticity after Incomplete Cervical Spinal Cord Injury in Adult Rats

2015 ◽  
Vol 32 (12) ◽  
pp. 893-907 ◽  
Author(s):  
Elisa Janine Gonzalez-Rothi ◽  
Angela M. Rombola ◽  
Celeste A. Rousseau ◽  
Lynne M. Mercier ◽  
Garrett M. Fitzpatrick ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spinal Cord ◽  
Cervical Spinal Cord Injury ◽  
Adult Rats ◽  
Spinal Interneurons ◽  
Cord Injury

scholarly journals Neuronal progenitor transplantation and respiratory outcomes following upper cervical spinal cord injury in adult rats

2010 ◽  
Vol 225 (1) ◽  
pp. 231-236 ◽  
Author(s):  
Todd E. White ◽  
Michael A. Lane ◽  
Milapjit S. Sandhu ◽  
Barbara E. O'Steen ◽  
David D. Fuller ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spinal Cord ◽  
Cervical Spinal Cord Injury ◽  
Adult Rats ◽  
Neuronal Progenitor ◽  
Cord Injury ◽  
Upper Cervical ◽  
Respiratory Outcomes

scholarly journals Upper extremity skeletal muscle adaptations following high cervical spinal cord injury (SCI) in adult rats

2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
Elisa J Gonzalez‐Rothi ◽  
Luther C Gill ◽  
Kun‐Ze Lee ◽  
Brendan J Dougherty ◽  
Paul J Reier ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Upper Extremity ◽  
Cervical Spinal Cord ◽  
Adult Rats ◽  
Cord Injury ◽  
Muscle Adaptations ◽  
High Cervical ◽  
Skeletal Muscle Adaptations

scholarly journals Characterization of Volitional Electromyographic Signals in the Lower Extremity After Motor Complete Spinal Cord Injury

2017 ◽  
Vol 31 (6) ◽  
pp. 583-591 ◽  
Author(s):  
Elizabeth Heald ◽  
Ronald Hart ◽  
Kevin Kilgore ◽  
P. Hunter Peckham
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Extremity ◽  
Visual Inspection ◽  
Surface Emg ◽  
Emg Activity ◽  
Automatic Identification ◽  
Emg Signal ◽  
Cord Injury ◽  
Complete Spinal Cord Injury

Background. Previous studies have demonstrated the presence of intact axons across a spinal cord lesion, even in those clinically diagnosed with complete spinal cord injury (SCI). These axons may allow volitional motor signals to be transmitted through the injury, even in the absence of visible muscle contraction. Objective. To demonstrate the presence of volitional electromyographic (EMG) activity below the lesion in motor complete SCI and to characterize this activity to determine its value for potential use as a neuroprosthetic command source. Methods. Twenty-four subjects with complete (AIS A or B), chronic, cervical SCI were tested for the presence of volitional below-injury EMG activity. Surface electrodes recorded from 8 to 12 locations of each lower limb, while participants were asked to attempt specific movements of the lower extremity in response to visual and audio cues. EMG trials were ranked through visual inspection, and were scored using an amplitude threshold algorithm to identify channels of interest with volitional motor unit activity. Results. Significant below-injury muscle activity was identified through visual inspection in 16 of 24 participants, and visual inspection rankings were well correlated to the algorithm scoring. Conclusions. The surface EMG protocol utilized here is relatively simple and noninvasive, ideal for a clinical screening tool. The majority of subjects tested were able to produce a volitional EMG signal below their injury level, and the algorithm developed allows automatic identification of signals of interest. The presence of this volitional activity in the lower extremity could provide an innovative new command signal source for implanted neuroprostheses or other assistive technology.

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