Towards a miniaturized brain-machine-spinal cord interface (BMSI) for restoration of function after spinal cord injury

Shahdoost, Shahab; Frost, Shawn B.; Acker, Gustaf Van; DeJong, Stacey L.; Dunham, Caleb; Barbay, Scott; Nudo, Randolph J.; Mohseni, Pedram

doi:10.1109/embc.2014.6943634

Cited by 17 publications

(11 citation statements)

References 9 publications

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“…Moreover, the use of volitional intent signals for intuitive control of ISMS paradigms for standing and walking will also be utilized (Mushahwar et al, 2006, Moritz et al, 2008, Ethier et al, 2012, Shahdoost et al, 2014, Shahdoost et al, 2015). ISMS may also be used as a therapeutic approach to promote targeted plasticity and long-term recovery after incomplete SCI (Mondello et al, 2014, McPherson et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

Intraspinal microstimulation produces over-ground walking in anesthetized cats

et al. 2016

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Objective Spinal cord injury causes a drastic loss of motor, sensory and autonomic function. The goal of this project was to investigate the use of intraspinal microstimulation (ISMS) for producing long distances of walking over ground. ISMS is an electrical stimulation method developed for restoring motor function by activating spinal networks below the level of an injury. It produces movements of the legs by stimulating the ventral horn of the lumbar enlargement using fine penetrating electrodes (≤ 50µm diameter). Approach In each of five adult cats (4.2–5.5kg), ISMS was applied through 16 electrodes implanted with tips targeting lamina IX in the ventral horn bilaterally. A desktop system implemented a physiologically-based control strategy that delivered different stimulation patterns through groups of electrodes to evoke walking movements with appropriate limb kinematics and forces corresponding to swing and stance. Each cat walked over an instrumented 2.9m walkway and limb kinematics and forces were recorded. Main Results Both propulsive and supportive forces were required for over-ground walking. Cumulative walking distances ranging from 609m to 835m (longest tested) were achieved in three animals. In these three cats, the mean peak supportive force was 3.5±0.6N corresponding to full-weight-support of the hind legs, while the angular range of the hip, knee, and ankle joints were 23.1±2.0°, 29.1±0.2°, and 60.3±5.2°, respectively. To further demonstrate the viability of ISMS for future clinical use, a prototype implantable module was successfully implemented in a subset of trials and produced comparable walking performance. Significance By activating inherent locomotor networks within the lumbosacral spinal cord, ISMS was capable of producing bilaterally coordinated and functional over-ground walking with current amplitudes <100 µA. These exciting results suggest that ISMS may be an effective intervention for restoring functional walking after spinal cord injury.

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Section: Discussionmentioning

confidence: 99%

Intraspinal microstimulation produces over-ground walking in anesthetized cats

et al. 2016

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“…Patients with SCI may be able to live a virtually normal lifespan with sophisticated postoperative care but are left with chronic paralysis below the spinal cord lesion. BCSC interface devices, in which recorded signals from the motor cortex drive stimulating electrodes in the spinal cord to evoke movement, are becoming more feasible (Shahdoost, Frost et al 2014, Shahdoost, Mohseni et al 2014, Shahdoost, Frost et al 2015). However, the overall design of these devices and final placement parameters are still challenging issues that have yet to be overcome.…”

Section: Discussionmentioning

confidence: 99%

A 3D map of the hindlimb motor representation in the lumbar spinal cord in Sprague Dawley rats

et al. 2016

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Objective Spinal cord injury (SCI) is a devastating neurological trauma with a prevalence of about 282,000 people living with an SCI in the United States in 2016. Advances in neuromodulatory devices hold promise for restoring function by incorporating the delivery of electrical current directly into the spinal cord grey matter via intraspinal microstimulation (ISMS). In such designs, detailed topographic maps of spinal cord outputs are needed to determine ISMS locations for eliciting hindlimb movements. The primary goal of the present study was to derive a topographic map of functional motor outputs in the lumbar spinal cord to hindlimb skeletal muscles as defined by ISMS in a rat model. Approach Experiments were carried out in nine healthy, adult, male, Sprague Dawley rats. After a laminectomy of the T13-L1 vertebrae and removal of the dura mater, a four-shank, 16-channel microelectrode array was inserted along a three-dimensional (200 µm) stimulation grid. Trains of three biphasic current pulses were used to determine evoked movements and EMG activity. Via fine wire electromyographic (EMG) electrodes, Stimulus-Triggered Averaging (StTA) was used on rectified EMG data to determine response latency. Main results Hindlimb movements were elicited at a median current intensity of 6 µA, and thresholds were significantly lower in ventrolateral sites. Movements typically consisted of whole leg, hip, knee, ankle, toe, and trunk movements. Hip movements dominated rostral to the T13 vertebral segment, knee movements were evoked at the T13-L1 vertebral junction, while ankle and digit movements were found near the rostral L1 vertebra. Whole leg movements spanned the entire rostrocaudal region explored, while trunk movements dominated medially. StTAs of EMG activity demonstrated a latency of ~4 ms. Significance The derived motor map provides insight into the parameters needed for future neuromodulatory devices.

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“…Dans une perspective supplémentaire, une telle approche hybride nécessitera également d'être prolongé 'in vivo' afin d'évaluer s'il peut aussi aider à récupérer les capacités de locomotion chez les animaux adultes sujets aux lésions chroniques de la moelle épinière. Des recherches ont été menées sur la colonne vertebrale de chiens [GUE06] [MAZ12], des résultats ont déjà été obtenu chez les rats [SHA14] et chez les primates [CAP16].…”

Section: Resultsunclassified

Central Pattern Generators (CPG) biomimétiques en temps-réel sur FPGA pour des expérimentations biohybrides

Ambroise¹,

Joucla²,

Yvert³

et al. 2017

IngeCog

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L'hybridation est une technique qui consiste à interconnecter un réseau de neurones biologiques et un réseau de neurones artificiels. Elle est notamment utilisée dans la recherche en neuroscience et à des fins thérapeutiques. L'objectif à long-terme est de remplacer les réseaux de neurones endommagés par des systèmes artificiels. Ceux-ci requièrent le développement de modèles de neurones dont l'activité électrique est similaire à l'activité des réseaux biologiques vivants. Cette correspondance permet de produire une stimulation adéquate afin de restaurer la fonction neurale désirée. Dans cet article, un réseau de neurones artificiels numériques avec une architecture configurable a été réalisé. Le réseau de neurones artificiels permet d'émuler l'activité de CPGs (Central Pattern Generator), à l'origine de la locomotion chez les animaux. Cette activité permet de déclencher une série de stimulations sur une moelle épinière lésée et de recréer ainsi la locomotion précédemment perdue. Ces résultats sont une première étape vers des solutions hybrides artificiel / biologique basées sur la micro-stimulation électrique pour la restauration de fonctions du Système Nerveux Central (SNC). ABSTRACT. Hybridization is a technique that consists in interconnecting a network of biological neurons and a network of artificial neurons. It is used in neuroscience research and for therapeutic purposes. The long-term goal is to replace damaged neural networks by these artificial systems. These require the development of models of neurons whose electrical activity is similar to the activity of living biological networks. This correspondence allows to produce an adequate stimulation in order to restore the desired neural function. In this paper, digital artificial neural network with a configurable architecture has been designed. This network of artificial neurons emulates the activity of CPGs (Central Pattern Generator), at the origin of the locomotion. This activity triggers a series of stimulations on an injured spinal cord and thus recreates the previously locomotion. These results are a first step toward hybrid artificial/biological solutions based on electrical micro-stimulation for the restoration of lost function in the injured CNS (like locomotion). MOTS-CLÉS. FPGA, réseau de neurones, Izhikevich, colonne vertébrale, expérimentation hybride.

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Towards a miniaturized brain-machine-spinal cord interface (BMSI) for restoration of function after spinal cord injury

Cited by 17 publications

References 9 publications

Intraspinal microstimulation produces over-ground walking in anesthetized cats

Intraspinal microstimulation produces over-ground walking in anesthetized cats

A 3D map of the hindlimb motor representation in the lumbar spinal cord in Sprague Dawley rats

Central Pattern Generators (CPG) biomimétiques en temps-réel sur FPGA pour des expérimentations biohybrides

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