Publications by authors named "Kelli Sharp"

Structural neuroplasticity in the brain may contribute to the persistence of low back pain (LBP) symptoms and the disability associated with them. It is not known if structural adaptations are evident early in the lifespan in young adults with LBP. This study compared gray matter in cortical sensorimotor regions in young adults with and without persistent LBP and identified gray matter and clinical predictors of pain-related disability.

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Altered postural control in the trunk/hip musculature is a characteristic of multiple neurological and musculoskeletal conditions. Previously it was not possible to determine if altered cortical and subcortical sensorimotor brain activation underlies impairments in postural control. This study used a novel fMRI-compatible paradigm to identify the brain activation associated with postural control in the trunk and hip musculature.

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Study Design: Randomized, controlled single-blind cross over study. This study was registered on ClinicalTrials.gov (NCT02473614).

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The ankles of ballet dancers are routinely under heavy loading that may lead to osteoarthritic changes. It would be clinically useful to identify such pathology as early as possible in a dancer's career. Therefore, the purpose of this study was to compare quantitative measurements in magnetic resonance (MR) images of the talocrural and talonavicular joints in ballet dancers and healthy non-dancers for use in formulating prediction of chronic injury and degenerative joint disease in these locations.

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Background: Since ballet dancers begin their training before skeletal maturity, accurate and non-invasive identification of cartilage diseases is clinically important. Angle-dependent analysis of T1rho and T2 sequences can be useful for quantification of the composition of cartilage.

Purpose: To investigate the angle-dependent T1rho and T2 profiles of ankle cartilage in non-dancers and dancers.

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Children with cerebral palsy (CP) have motor impairments that make it challenging for them to participate in standard physical activity (PA) interventions. There is a need to evaluate adapted PA interventions for this population. Dance can promote coordination, posture, muscle strength, motor learning, and executive functioning.

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Introduction: The Badges Program is a self-directed supplement to a program's research curriculum. This step-by-step resource helps medical residents to understand the resources needed to conduct their own research project and fulfill the Accreditation Council for Graduate Medical Education requirements for scholarly activity.

Methods: The curriculum is completed over varying amounts of time depending on the intricacy of scholastic activities.

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After complete spinal cord injury (SCI), activation during attempted movement of paralyzed limbs is sharply reduced, but after incomplete SCI-the more common form of human injury-it is unknown how attempts to move voluntarily are accompanied by activation of brain motor and sensory networks. Here, we assessed brain activation during ankle movement in subjects with incomplete SCI, among whom voluntary motor function is partially preserved. Adults with incomplete SCI (n = 20) and healthy controls (n = 15) underwent functional magnetic resonance imaging that alternated rest with 0.

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Peripheral nerve injury induces increased expression of thrombospondin-4 (TSP4) in spinal cord and dorsal root ganglia that contributes to neuropathic pain states through unknown mechanisms. Here, we test the hypothesis that TSP4 activates its receptor, the voltage-gated calcium channel Cavα2δ1 subunit (Cavα2δ1), on sensory afferent terminals in dorsal spinal cord to promote excitatory synaptogenesis and central sensitization that contribute to neuropathic pain states. We show that there is a direct molecular interaction between TSP4 and Cavα2δ1 in the spinal cord in vivo and that TSP4/Cavα2δ1-dependent processes lead to increased behavioral sensitivities to stimuli.

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Rodent models of spinal cord injury are critical for the development of treatments for upper limb motor impairment in humans, but there are few methods for measuring forelimb strength of rodents, an important outcome measure. We developed a novel robotic device--the Robotic Rehabilitator of the Rodent Upper Extremity (RUE)--that requires rats to voluntarily reach for and pull a bar to retrieve a food reward; the resistance of the bar can be programmed. We used RUE to train forelimb strength of 16 rats three times per week for 23 weeks before and 38 weeks after a mild (100 kdyne) unilateral contusion at the cervical level 5 (C5).

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We reported previously the formation of ectopic colonies in widespread areas of the nervous system after transplantation of fetal neural stem cells (NSCs) into spinal cord transection sites. Here, we characterize the incidence, distribution, and cellular composition of the colonies. NSCs harvested from E14 spinal cords from rats that express GFP were treated with a growth factor cocktail and grafted into the site of a complete spinal cord transection.

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As part of the NIH "Facilities of Research Excellence-Spinal Cord Injury" project to support independent replication, we repeated key parts of a study reporting robust engraftment of neural stem cells (NSCs) treated with growth factors after complete spinal cord transection in rats. Rats (n=20) received complete transections at thoracic level 3 (T3) and 2weeks later received NSC transplants in a fibrin matrix with a growth factor cocktail using 2 different transplantation methods (with and without removal of scar tissue). Control rats (n=9) received transections only.

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To investigate a potential mechanism underlying trigeminal nerve injury-induced orofacial hypersensitivity, we used a rat model of chronic constriction injury to the infraorbital nerve (CCI-ION) to study whether CCI-ION caused calcium channel α2δ1 (Cavα2δ1) protein dysregulation in trigeminal ganglia and associated spinal subnucleus caudalis and C1/C2 cervical dorsal spinal cord (Vc/C2). Furthermore, we studied whether this neuroplasticity contributed to spinal neuron sensitization and neuropathic pain states. CCI-ION caused orofacial hypersensitivity that correlated with Cavα2δ1 up-regulation in trigeminal ganglion neurons and Vc/C2.

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This study was undertaken as part of the NIH "Facilities of Research Excellence-Spinal Cord Injury" project to support independent replication of published studies. Here, we repeat key parts of a study reporting that rats treated with imatinib (Gleevec®, Novartis) after spinal cord contusion injury exhibited enhanced bladder function, greater recovery of motor function, and increased tissue sparing. Young adult female SCA Sprague-Dawley rats received moderate contusion injuries at T9-T10 using the MASCIS weight drop device.

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Objective: To compare the efficacy of a regimen combining mental practice (MP) with overground training (OT) with the efficacy of a regimen consisting of OT only on gait velocity and lower extremity motor outcomes in individuals with chronic (>12mo postinjury), incomplete spinal cord injury (SCI).

Design: Randomized, controlled, single-blinded study.

Setting: Outpatient rehabilitation laboratories.

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Robotic devices can modulate success rates and required effort levels during motor training, but it is unclear how this affects performance gains and motivation. Here we present results from training unimpaired humans in a virtual golf-putting task, and training spinal cord injured (SCI) rats in a grip strength task using robotically modulated success rates and effort levels. Robotic assistance in golf practice increased trainees feelings of competence, and, paradoxically, increased their sense effort, even though it had mixed effects on learning.

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Background: Good motor outcome after stroke has been found to correlate with increased activity in a dorsal premotor (PMd) brain circuit, suggesting that therapeutic strategies targeting this circuit might have a favorable, causal influence on motor status.

Objective: This study addressed the hypothesis that a Premotor Therapy that exercises normal PMd functions would provide greater behavioral gains than would standard Motor Therapy; and that Premotor Therapy benefits would be greatest in patients with greater preservation of PMd circuit elements.

Methods: Patients with chronic hemiparetic stroke (n = 15) were randomized to 2-weeks of Premotor Therapy or Motor Therapy, implemented through a robotic device.

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This study was undertaken as part of the NIH "Facilities of Research Excellence-Spinal Cord Injury" project to support independent replication of published studies. Here, we repeat key parts of a study reporting that rats treated with ibuprofen via subcutaneous minipump exhibited greater recovery of motor function and enhanced axonal growth after spinal cord injury. We carried out 3 separate experiments in which young adult female Sprague-Dawley rats received dorsal over-hemisections at T6-T7, and then were implanted with osmotic minipumps for subcutaneous delivery of ibuprofen or saline.

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Neuropathic pain is a common cause of pain after nerve injury, but its molecular basis is poorly understood. In a post-gene chip microarray effort to identify new target genes contributing to neuropathic pain development, we report here the characterization of a novel neuropathic pain contributor, thrombospondin-4 (TSP4), using a neuropathic pain model of spinal nerve ligation injury. TSP4 is mainly expressed in astrocytes and significantly upregulated in the injury side of dorsal spinal cord that correlates with the development of neuropathic pain states.

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The neural degeneration caused by spinal cord injury leaves a cavity at the injury site that greatly inhibits repair. One approach to promoting repair is to fill the cavity with a scaffold to limit further damage and encourage regrowth. Injectable materials are advantageous scaffolds because they can be placed as a liquid in the lesion site then form a solid in vivo that precisely matches the contours of the lesion.

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Spinal cord injury-induced pain is a common clinical problem affecting adversely the quality of daily lives of spinal cord injured patients. Management with current pain medications can only lead to partial pain relief in some spinal cord injured patients, which is usually associated with unfavorable side effects. Development of specific medications for spinal cord injury-induced pain states relies on identification of new targets and/or pathways that contribute to chronic pain development post injury.

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This study was undertaken as part of the NIH "Facilities of Research Excellence-Spinal Cord Injury" project to support independent replication of published studies. Here, we repeat an experiment in which rats that received an inhibitor of the epidermal growth factor receptor (EGFR) exhibited greater sparing/recovery of bladder and motor function and enhanced sparing at the lesion site after contusion injuries at the thoracic level. Young adult female Sprague-Dawley rats received moderate contusions with the NYU impactor (10 g from 12.

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This study was undertaken as part of the NIH "Facilities of Research Excellence-Spinal Cord Injury", which supports independent replication of published studies. Here, we repeat an experiment reporting that intracortical delivery of inosine promoted trans-midline growth of corticospinal tract (CST) axons in the spinal cord after unilateral injury to the medullary pyramid. Rats received unilateral transections of the medullary pyramid and 1 day later, a cannula assembly was implanted into the sensorimotor cortex contralateral to the pyramidotomy to deliver either inosine or vehicle.

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Spinal cord injury (SCI) commonly results in the development of neuropathic pain, which can dramatically impair the quality of life for SCI patients. SCI-induced neuropathic pain can be manifested as both tactile allodynia (a painful sensation to a non-noxious stimulus) and hyperalgesia (an enhanced sensation to a painful stimulus). The mechanisms underlying these pain states are poorly understood.

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