Robot-driven spinal epidural stimulation compared with conventional stimulation in adult spinalized rats

Journal of Neuroscience Methods

2014

Background Rodents are important model systems used to explore Spinal Cord Injury (SCI) and rehabilitation, and Brain Machine Interfaces. We present a new method to provide mechanical interaction for BMI and rehabilitation in rat models of SCI. New Method We present the design and implantation procedures for a pelvic orthosis that allows direct force application to the skeleton in brain machine interface and robot rehabilitation applications in rodents. We detail the materials, construction, machining, surgery and validation of the device. Results We describe the statistical validation of the implant procedures by comparing stepping parameters of 8 rats prior to and after implantation and surgical recovery. An ANOVA showed no effects of the implantation on stepping. Paired tests in the individual rats also showed no effect in 7/8 rats and minor effects in the last rat, within the group's variance. Comparison with Existing Methods Our method allows interaction with rats at the pelvis without any perturbation of normal stepping in the intact rat. The method bypasses slings, and cuffs, avoiding cuff or slings squeezing the abdomen, or other altered sensory feedback. Our implant osseointegrates, and thus allows an efficient high bandwidth mechanical coupling to a robot. The implants support quadrupedal training and are readily integrated into either treadmill or overground contexts. Conclusions Our novel device and procedures support a range of novel experimental designs and motor tests for rehabilitative and augmentation devices in intact and SCI model rats, with the advantage of allowing direct force application at the pelvic bones.

Section: Resultsmentioning

confidence: 99%

A pelvic implant orthosis in rodents, for spinal cord injury rehabilitation, and for brain machine interface research: Construction, surgical implantation and validation

Udoekwere

Journal of Neuroscience Methods

2014

“…Song et al, 2009;W. Song and Giszter, 2011;Hsieh and Giszter, 2011;Oza and Giszter, 2014). A total of 38 NWS NTX rats without pelvic implants served as additional controls.…”

Section: Methodsmentioning

confidence: 99%

“…sponding rats might have benefited from pretraining with a legbased therapy (Timoszyk et al, 2002, pharmacological (Kao et al, 2006), or electrical stimulation intervention (Hsieh and Giszter, 2011;Gad et al, 2013). With the means to identify responders and nonresponders described here, it is now feasible in the future to test this.…”

Section: The Conversion To Weight Supportmentioning

confidence: 99%

“…Robotic body-weight-support training of motor-incomplete human SCI patients induced plasticity in sensorimotor cortical regions in fMRI (Winchester et al, 2005). Sensory plasticity follows passive motion, bulk repetitive exercise, or skill development in animal SCI models (Kao et al, 2006;Graziano et al, 2013;Moxon et al, 2013). In NTX rats, high weight support achieved autonomously associates with specific motor representations.…”

Section: Spinal and Supraspinal Rolesmentioning

confidence: 99%

“…Approximately 14 -20 d following pelvic implantation surgery, NTX rats began robotic rehabilitation training similar to that described by Udoekwere et al (2006) and Hsieh et al (2011) (Fig. 1C).…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Teaching Adult Rats Spinalized as Neonates to Walk Using Trunk Robotic Rehabilitation: Elements of Success, Failure, and Dependence

Udoekwere

Journal of Neuroscience

2016

Self Cite

Robot therapy promotes functional recovery after spinal cord injury (SCI) in animal and clinical studies. Trunk actions are important in adult rats spinalized as neonates (NTX rats) that walk autonomously. Quadrupedal robot rehabilitation was tested using an implanted orthosis at the pelvis. Trunk cortical reorganization follows such rehabilitation. Here, we test the functional outcomes of such training. Robot impedance control at the pelvis allowed hindlimb, trunk, and forelimb mechanical interactions. Rats gradually increased weight support. Rats showed significant improvement in hindlimb stepping ability, quadrupedal weight support, and all measures examined. Function in NTX rats both before and after training showed bimodal distributions, with "poor" and "high weight support" groupings. A total of 35% of rats initially classified as "poor" were able to increase their weight-supported step measures to a level considered "high weight support" after robot training, thus moving between weight support groups. Recovered function in these rats persisted on treadmill with the robot both actuated and nonactuated, but returned to pretraining levels if they were completely disconnected from the robot. Locomotor recovery in robot rehabilitation of NTX rats thus likely included context dependence and/or incorporation of models of robot mechanics that became essential parts of their learned strategy. Such learned dependence is likely a hurdle to autonomy to be overcome for many robot locomotor therapies. Notwithstanding these limitations, trunk-based quadrupedal robot rehabilitation helped the rats to visit mechanical states they would never have achieved alone, to learn novel coordinations, and to achieve major improvements in locomotor function.

Plasticity and alterations of trunk motor cortex following spinal cord injury and non-stepping robot and treadmill training

2014

Experimental Neurology

Spinal cord injury (SCI) induces significant reorganization in the sensorimotor cortex. Trunk motor control is crucial for postural stability and propulsion after low thoracic SCI and several rehabilitative strategies are aimed at trunk stability and control. However little is known about the effect of SCI and rehabilitation training on trunk motor representations and their plasticity in the cortex. Here, we used intracortical microstimulation to examine the motor cortex representations of the trunk in relation to other representations in three groups of chronic adult complete low thoracic SCI rats: chronic untrained, treadmill trained (but 'non-stepping') and robot assisted treadmill trained (but 'non-stepping') and compared with a group of normal rats. Our results demonstrate extensive and significant reorganization of the trunk motor cortex after chronic adult SCI which includes (1) expansion and rostral displacement of trunk motor representations in the cortex, with the greatest significant increase observed for rostral (to injury) trunk, and slight but significant increase of motor representation for caudal (to injury) trunk at low thoracic levels in all spinalized rats; (2) significant changes in coactivation and the synergy representation (or map overlap) between different trunk muscles and between trunk and forelimb. No significant differences were observed between the groups of transected rats for the majority of the comparisons. However, (3) the treadmill and robot-treadmill trained groups of rats showed a further small but significant rostral migration of the trunk representations, beyond the shift caused by transection alone. We conclude that SCI induces a significant reorganization of the trunk motor cortex, which is not qualitatively altered by non-stepping treadmill training or non-stepping robot assisted treadmill training, but is shifted further from normal topography by the training. This shift may potentially make subsequent rehabilitation with stepping longer or less successful.