scholarly journals Locomotor impact of beneficial or nonbeneficial H-reflex conditioning after spinal cord injury

2014 ◽  
Vol 111 (6) ◽  
pp. 1249-1258 ◽  
Author(s):  
Yi Chen ◽  
Lu Chen ◽  
Rongliang Liu ◽  
Yu Wang ◽  
Xiang Yang Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
H Reflex ◽  
Spinal Reflex ◽  
Step Cycle ◽  
Reflex Pathway ◽  
Cord Injury ◽  
Kinematic Analyses ◽  
Spinal Cord Contusion ◽  
The Right ◽  
The Impact

When new motor learning changes neurons and synapses in the spinal cord, it may affect previously learned behaviors that depend on the same spinal neurons and synapses. To explore these effects, we used operant conditioning to strengthen or weaken the right soleus H-reflex pathway in rats in which a right spinal cord contusion had impaired locomotion. When up-conditioning increased the H-reflex, locomotion improved. Steps became longer, and step-cycle asymmetry (i.e., limping) disappeared. In contrast, when down-conditioning decreased the H-reflex, locomotion did not worsen. Steps did not become shorter, and asymmetry did not increase. Electromyographic and kinematic analyses explained how H-reflex increase improved locomotion and why H-reflex decrease did not further impair it. Although the impact of up-conditioning or down-conditioning on the H-reflex pathway was still present during locomotion, only up-conditioning affected the soleus locomotor burst. Additionally, compensatory plasticity apparently prevented the weaker H-reflex pathway caused by down-conditioning from weakening the locomotor burst and further impairing locomotion. The results support the hypothesis that the state of the spinal cord is a “negotiated equilibrium” that serves all the behaviors that depend on it. When new learning changes the spinal cord, old behaviors undergo concurrent relearning that preserves or improves their key features. Thus, if an old behavior has been impaired by trauma or disease, spinal reflex conditioning, by changing a specific pathway and triggering a new negotiation, may enable recovery beyond that achieved simply by practicing the old behavior. Spinal reflex conditioning protocols might complement other neurorehabilitation methods and enhance recovery.

scholarly journals Persistent beneficial impact of H-reflex conditioning in spinal cord-injured rats

2014 ◽  
Vol 112 (10) ◽  
pp. 2374-2381 ◽  
Author(s):  
Yi Chen ◽  
Lu Chen ◽  
Yu Wang ◽  
Jonathan R. Wolpaw ◽  
Xiang Yang Chen
Keyword(s):  
Spinal Cord ◽  
H Reflex ◽  
Spinal Reflex ◽  
Spinal Cord Regeneration ◽  
Lateral Column ◽  
Beneficial Effects ◽  
Cord Injury ◽  
Beneficial Impact ◽  
The Right ◽  
Spinal Cord Injured

Operant conditioning of a spinal cord reflex can improve locomotion in rats and humans with incomplete spinal cord injury. This study examined the persistence of its beneficial effects. In rats in which a right lateral column contusion injury had produced asymmetric locomotion, up-conditioning of the right soleus H-reflex eliminated the asymmetry while down-conditioning had no effect. After the 50-day conditioning period ended, the H-reflex was monitored for 100 [±9 (SD)] (range 79–108) more days and locomotion was then reevaluated. After conditioning ended in up-conditioned rats, the H-reflex continued to increase, and locomotion continued to improve. In down-conditioned rats, the H-reflex decrease gradually disappeared after conditioning ended, and locomotion at the end of data collection remained as impaired as it had been before and immediately after down-conditioning. The persistence (and further progression) of H-reflex increase but not H-reflex decrease in these spinal cord-injured rats is consistent with the fact that up-conditioning improved their locomotion while down-conditioning did not. That is, even after up-conditioning ended, the up-conditioned H-reflex pathway remained adaptive because it improved locomotion. The persistence and further enhancement of the locomotor improvement indicates that spinal reflex conditioning protocols might supplement current therapies and enhance neurorehabilitation. They may be especially useful when significant spinal cord regeneration becomes possible and precise methods for retraining the regenerated spinal cord are needed.

scholarly journals Neuronal Actions of Transspinal Stimulation on Locomotor Networks and Reflex Excitability During Walking in Humans With and Without Spinal Cord Injury

2021 ◽  
Vol 15 ◽  
Author(s):  
Md. Anamul Islam ◽  
Timothy S. Pulverenti ◽  
Maria Knikou
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Single Pulse ◽  
H Reflex ◽  
Spinal Reflex ◽  
Emg Activity ◽  
Step Cycle ◽  
Reflex Excitability ◽  
Cord Injury ◽  
Modulation Pattern

This study investigated the neuromodulatory effects of transspinal stimulation on soleus H-reflex excitability and electromyographic (EMG) activity during stepping in humans with and without spinal cord injury (SCI). Thirteen able-bodied adults and 5 individuals with SCI participated in the study. EMG activity from both legs was determined for steps without, during, and after a single-pulse or pulse train transspinal stimulation delivered during stepping randomly at different phases of the step cycle. The soleus H-reflex was recorded in both subject groups under control conditions and following single-pulse transspinal stimulation at an individualized exactly similar positive and negative conditioning-test interval. The EMG activity was decreased in both subject groups at the steps during transspinal stimulation, while intralimb and interlimb coordination were altered only in SCI subjects. At the steps immediately after transspinal stimulation, the physiological phase-dependent EMG modulation pattern remained unaffected in able-bodied subjects. The conditioned soleus H-reflex was depressed throughout the step cycle in both subject groups. Transspinal stimulation modulated depolarization of motoneurons over multiple segments, limb coordination, and soleus H-reflex excitability during assisted stepping. The soleus H-reflex depression may be the result of complex spinal inhibitory interneuronal circuits activated by transspinal stimulation and collision between orthodromic and antidromic volleys in the peripheral mixed nerve. The soleus H-reflex depression by transspinal stimulation suggests a potential application for normalization of spinal reflex excitability after SCI.

scholarly journals Neurophysiological Changes After Paired Brain and Spinal Cord Stimulation Coupled With Locomotor Training in Human Spinal Cord Injury

2021 ◽  
Vol 12 ◽  
Author(s):  
Timothy S. Pulverenti ◽  
Morad Zaaya ◽  
Monika Grabowski ◽  
Ewelina Grabowski ◽  
Md. Anamul Islam ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Motor Cortex ◽  
Stance Phase ◽  
Training Session ◽  
H Reflex ◽  
Locomotor Training ◽  
Step Cycle ◽  
Human Spinal Cord ◽  
Cord Injury

Neurophysiological changes that involve activity-dependent neuroplasticity mechanisms via repeated stimulation and locomotor training are not commonly employed in research even though combination of interventions is a common clinical practice. In this randomized clinical trial, we established neurophysiological changes when transcranial magnetic stimulation (TMS) of the motor cortex was paired with transcutaneous thoracolumbar spinal (transspinal) stimulation in human spinal cord injury (SCI) delivered during locomotor training. We hypothesized that TMS delivered before transspinal (TMS-transspinal) stimulation promotes functional reorganization of spinal networks during stepping. In this protocol, TMS-induced corticospinal volleys arrive at the spinal cord at a sufficient time to interact with transspinal stimulation induced depolarization of alpha motoneurons over multiple spinal segments. We further hypothesized that TMS delivered after transspinal (transspinal-TMS) stimulation induces less pronounced effects. In this protocol, transspinal stimulation is delivered at time that allows transspinal stimulation induced action potentials to arrive at the motor cortex and affect descending motor volleys at the site of their origin. Fourteen individuals with motor incomplete and complete SCI participated in at least 25 sessions. Both stimulation protocols were delivered during the stance phase of the less impaired leg. Each training session consisted of 240 paired stimuli delivered over 10-min blocks. In transspinal-TMS, the left soleus H-reflex increased during the stance-phase and the right soleus H-reflex decreased at mid-swing. In TMS-transspinal no significant changes were found. When soleus H-reflexes were grouped based on the TMS-targeted limb, transspinal-TMS and locomotor training promoted H-reflex depression at swing phase, while TMS-transspinal and locomotor training resulted in facilitation of the soleus H-reflex at stance phase of the step cycle. Furthermore, both transspinal-TMS and TMS-transspinal paired-associative stimulation (PAS) and locomotor training promoted a more physiological modulation of motor activity and thus depolarization of motoneurons during assisted stepping. Our findings support that targeted non-invasive stimulation of corticospinal and spinal neuronal pathways coupled with locomotor training produce neurophysiological changes beneficial to stepping in humans with varying deficits of sensorimotor function after SCI.

scholarly journals Locomotor training improves reciprocal and nonreciprocal inhibitory control of soleus motoneurons in human spinal cord injury

2015 ◽  
Vol 113 (7) ◽  
pp. 2447-2460 ◽  
Author(s):  
Maria Knikou ◽  
Andrew C. Smith ◽  
Chaithanya K. Mummidisetty
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Injury ◽  
Reciprocal Inhibition ◽  
H Reflex ◽  
Medial Gastrocnemius ◽  
Locomotor Training ◽  
Step Cycle ◽  
Human Spinal Cord ◽  
Cord Injury

Pathologic reorganization of spinal networks and activity-dependent plasticity are common neuronal adaptations after spinal cord injury (SCI) in humans. In this work, we examined changes of reciprocal Ia and nonreciprocal Ib inhibition after locomotor training in 16 people with chronic SCI. The soleus H-reflex depression following common peroneal nerve (CPN) and medial gastrocnemius (MG) nerve stimulation at short conditioning-test (C-T) intervals was assessed before and after training in the seated position and during stepping. The conditioned H reflexes were normalized to the unconditioned H reflex recorded during seated. During stepping, both H reflexes were normalized to the maximal M wave evoked at each bin of the step cycle. In the seated position, locomotor training replaced reciprocal facilitation with reciprocal inhibition in all subjects, and Ib facilitation was replaced by Ib inhibition in 13 out of 14 subjects. During stepping, reciprocal inhibition was decreased at early stance and increased at midswing in American Spinal Injury Association Impairment Scale C (AIS C) and was decreased at midstance and midswing phases in AIS D after training. Ib inhibition was decreased at early swing and increased at late swing in AIS C and was decreased at early stance phase in AIS D after training. The results of this study support that locomotor training alters postsynaptic actions of Ia and Ib inhibitory interneurons on soleus motoneurons at rest and during stepping and that such changes occur in cases with limited or absent supraspinal inputs.

Locomotor training improves premotoneuronal control after chronic spinal cord injury

2014 ◽  
Vol 111 (11) ◽  
pp. 2264-2275 ◽  
Author(s):  
Maria Knikou ◽  
Chaithanya K. Mummidisetty
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Presynaptic Inhibition ◽  
H Reflex ◽  
Locomotor Training ◽  
Dependent Manner ◽  
Step Cycle ◽  
Cord Injury ◽  
Spinal Inhibition ◽  
Presynaptic Facilitation

Spinal inhibition is significantly reduced after spinal cord injury (SCI) in humans. In this work, we examined if locomotor training can improve spinal inhibition exerted at a presynaptic level. Sixteen people with chronic SCI received an average of 45 training sessions, 5 days/wk, 1 h/day. The soleus H-reflex depression in response to low-frequency stimulation, presynaptic inhibition of soleus Ia afferent terminals following stimulation of the common peroneal nerve, and bilateral EMG recovery patterns were assessed before and after locomotor training. The soleus H reflexes evoked at 1.0, 0.33, 0.20, 0.14, and 0.11 Hz were normalized to the H reflex evoked at 0.09 Hz. Conditioned H reflexes were normalized to the associated unconditioned H reflex evoked with subjects seated, while during stepping both H reflexes were normalized to the maximal M wave evoked after the test H reflex at each bin of the step cycle. Locomotor training potentiated homosynaptic depression in all participants regardless the type of the SCI. Presynaptic facilitation of soleus Ia afferents remained unaltered in motor complete SCI patients. In motor incomplete SCIs, locomotor training either reduced presynaptic facilitation or replaced presynaptic facilitation with presynaptic inhibition at rest. During stepping, presynaptic inhibition was modulated in a phase-dependent manner. Locomotor training changed the amplitude of locomotor EMG excitability, promoted intralimb and interlimb coordination, and altered cocontraction between knee and ankle antagonistic muscles differently in the more impaired leg compared with the less impaired leg. The results provide strong evidence that locomotor training improves premotoneuronal control after SCI in humans at rest and during walking.

scholarly journals Operant Conditioning of Reciprocal Inhibition in Rat Soleus Muscle

2006 ◽  
Vol 96 (4) ◽  
pp. 2144-2150 ◽  
Author(s):  
Xiang Yang Chen ◽  
Lu Chen ◽  
Yi Chen ◽  
Jonathan R. Wolpaw
Keyword(s):  
Spinal Cord ◽  
Operant Conditioning ◽  
Reciprocal Inhibition ◽  
H Reflex ◽  
Spinal Reflex ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Cord Injury ◽  
Rat Soleus Muscle ◽  
Spinal Stretch Reflex

Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex (SSR), induces activity-dependent plasticity in the spinal cord and might be used to improve locomotion after spinal cord injury. To further assess the potential clinical significance of spinal reflex conditioning, this study asks whether another well-defined spinal reflex pathway, the disynaptic pathway underlying reciprocal inhibition (RI), can also be operantly conditioned. Sprague-Dawley rats were implanted with electromyographic (EMG) electrodes in right soleus (SOL) and tibialis anterior (TA) muscles and a stimulating cuff on the common peroneal (CP) nerve. When background EMG in both muscles remained in defined ranges, CP stimulation elicited the TA H-reflex and SOL RI. After collection of control data for 20 days, each rat was exposed for 50 days to up-conditioning (RIup mode) or down-conditioning (RIdown mode) in which food reward occurred if SOL RI evoked by CP stimulation was more (RIup mode) or less (RIdown mode) than a criterion. TA and SOL background EMG and TA M response remained stable. In every rat, RI conditioning was successful (i.e., change ≥20% in the correct direction). In the RIup rats, final SOL RI averaged 171± 28% (mean ± SE) of control, and final TA H-reflex averaged 114 ± 14%. In the RIdown rats, final SOL RI averaged 37 ± 13% of control, and final TA H-reflex averaged 60 ± 18%. Final SOL RI and TA H-reflex sizes were significantly correlated. Thus like the SSR and the H-reflex, RI can be operantly conditioned; and conditioning one reflex can affect another reflex as well.

Conditioned H-Reflex Increase Persists After Transection of the Main Corticospinal Tract in Rats

2003 ◽  
Vol 90 (5) ◽  
pp. 3572-3578 ◽  
Author(s):  
Xiang Yang Chen ◽  
Lu Chen ◽  
Jonathan R. Wolpaw
Keyword(s):  
Spinal Cord ◽  
Operant Conditioning ◽  
Corticospinal Tract ◽  
Dorsal Column ◽  
H Reflex ◽  
Initial Value ◽  
Cord Injury ◽  
Training Mode ◽  
The Right ◽  
Spinal Stretch Reflex

The brain shapes spinal cord function throughout life. Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex (SSR), is a relatively simple model for exploring the spinal cord plasticity underlying this functional change and may provide a new method for modifying spinal cord reflexes after spinal cord injury. In response to an operant conditioning protocol, rats can gradually increase (i.e., up-training mode) or decrease (i.e., down-training mode) the soleus H-reflex. This study explored the effects of midthoracic transection of the ipsilateral lateral column (LC) (rubrospinal, vestibulospinal, and reticulospinal tracts), the dorsal column corticospinal tract (CST), or the dorsal column ascending tract (DA) on maintenance of an H-reflex increase that has already occurred. Rats were implanted with EMG electrodes in the right soleus muscle and a nerve-stimulating cuff on the right posterior tibial nerve. After initial (i.e., control) H-reflex size was determined, the rats were exposed for 50 days to the up-training mode, in which reward was given when the H-reflex was above a criterion value. H-reflex size gradually rose to 168 ± 12% (mean ± SE) of its initial value. Each rat then received an LC, CST, or DA transection and continued under the up-training mode for 50 more days. None of the transections abolished the H-reflex increase. H-reflex size increased further to 197 ± 19% of its initial value and did not differ significantly among LC, CST, and DA rats ( P > 0.78 by ANOVA). Although earlier studies show that the main CST is needed for acquisition of H-reflex up-training and down-training and for maintenance of down-training, this study shows that it is not needed for maintenance of up-training. It adds to the evidence that H-reflex conditioning changes the spinal cord and that the spinal cord plasticity associated with up-training is different from that associated with down-training.

scholarly journals Understanding the impact of isolation due to COVID-19 on employment for Kentuckians with spinal cord injuries

2020 ◽  
pp. 1-7
Author(s):  
Chithra Adams ◽  
Anthony Lobianco ◽  
Emily Moseley ◽  
Calisa Fitzpatrick
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injuries ◽  
Physical And Mental Health ◽  
Skill Sets ◽  
Rehabilitation Professionals ◽  
Health And Wellbeing ◽  
Cord Injury ◽  
Virtual Focus Groups ◽  
The Right ◽  
The Impact

BACKGROUND: Obtaining and retaining employment for persons with spinal cord injury (SCI) is frequently a greater challenge than it is for the non-SCI population. It is particularly difficult during COVID-19 because all the barriers to employment are compounded for people with SCI as they have to take extra precaution to protect their health and wellbeing. OBJECTIVE: The objective of the study was to understand how isolation related to COVID-19 has had an effect on the employment experiences for persons living with SCI. METHODS: Three virtual focus groups were conducted with Kentuckians who had SCI. RESULTS: The major themes were: the impact of disruption in routine on physical and mental health, importance of having the right accommodations, working from home as an accommodation, and the uncertainty of work. CONCLUSIONS: Accommodations are a critical component for people with SCI to be retained in the workforce. Employers should be proactive in offering various inclusive and accessible accommodations to employees so that people do not have to bear the additional burden of asking for accommodations. Rehabilitation professionals would serve the SCI population well by finding ways to help clients better advocate for themselves, provide adaptive home therapeutic equipment, and help identify diverse employment skill sets.

scholarly journals A geospatial examination of specialist care accessibility and impact on health outcomes for patients with acute traumatic spinal cord injury in NSW, Australia: a whole population record linkage study

2020 ◽  
Author(s):  
Lisa Nicole Sharwood ◽  
Bharat P Vaikuntam ◽  
Christiana L Cheng ◽  
Vanessa Noonan ◽  
Anthony P Joseph ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Record Linkage ◽  
Linkage Study ◽  
Traumatic Spinal Cord Injury ◽  
Specialist Care ◽  
Post Injury ◽  
Cord Injury ◽  
The Right ◽  
The Impact

Background Timely treatment is essential for achieving optimal outcomes after traumatic spinal cord injury (TSCI), and expeditious transfer to a specialist spinal cord injury unit (SCIU) is recommended within 24 hours from injury. Previous research in New South Wales (NSW) found only 57% of TSCI patients were admitted to SCIU for acute post-injury care; 73% transferred within 24 hours from injury. Methods This record linkage study included administrative pre-hospital, admissions and costs data for all patients aged ≥16 years with incident TSCI in NSW (2013-2016). Its aim was to examine potential geographical disparities in access to specialist care following TSCI using geospatial methods, and to better understand the impact of post-injury care pathways on patient outcomes. Results Of 316 cases with geospatial data, injury location analysis showed that over half (53%, n=168) of all patients were injured within 60 minutes road travel of a SCIU, yet only 28.6% (n=48) were directly transferred to a SCIU. Direct transfers received earlier operative intervention (median (IQR) 12.9(7.9) hours), compared with patients transferred indirectly to SCIU (median (IQR) 19.5(18.9) hours), and had lower risk of complications (OR 3.2 v 1.4, p<0.001). Conclusions Getting patients with acute TSCI patients to the right place at the right time is dependent on numerous factors; some are still being triaged directly to non-trauma services which delays specialist and surgical care and increases complication risks. More stringent adherence to recommended guidelines would prioritise direct SCIU transfer for patients injured within 60 minutes radius, enabling the benefits of specialised care.   

Sign in / Sign up

Export Citation Format

Share Document