Motor system | EPFL Graph Search

The motor system is the set of central and peripheral structures in the nervous system that support motor functions, i.e. movement. Peripheral structures may include skeletal muscles and neural connections with muscle tissues. Central structures include cerebral cortex, brainstem, spinal cord, pyramidal system including the upper motor neurons, extrapyramidal system, cerebellum, and the lower motor neurons in the brainstem and the spinal cord. The motor system is a biological system with close ties to the muscular system and the circulatory system. To achieve motor skill, the motor system must accommodate the working state of the muscles, whether hot or cold, stiff or loose, as well as physiological fatigue. Pyramidal motor system Pyramidal tracts The pyramidal motor system, also called the pyramidal tract or the corticospinal tract, start in the motor center of the cerebral cortex. There are upper and lower motor neurons in the corticospinal tr

Miniature neurotransmission is required to maintain Drosophila synaptic structures during ageing

Soumya Banerjee, Olivier Burri, Wei Jiao, Brian Donal McCabe, Evelyne Ruchti

The decline of neuronal synapses is an established feature of ageing accompanied by the diminishment of neuronal function, and in the motor system at least, a reduction of behavioural capacity. Here, we have investigated Drosophila motor neuron synaptic terminals during ageing. We observed cumulative fragmentation of presynaptic structures accompanied by diminishment of both evoked and miniature neurotransmission occurring in tandem with reduced motor ability. Through discrete manipulation of each neurotransmission modality, we find that miniature but not evoked neurotransmission is required to maintain presynaptic architecture and that increasing miniature events can both preserve synaptic structures and prolong motor ability during ageing. Our results establish that miniature neurotransmission, formerly viewed as an epiphenomenon, is necessary for the long-term stability of synaptic connections. Synaptic structures disintegrate and fragment as ageing progresses. Here the authors find that miniature neurotransmission is required to maintain adult motor synapse structures in Drosophila and that increasing miniature events can preserve motor ability during ageing.

NATURE RESEARCH2021

Neuroprosthetic Technologies to Evaluate and Train Leg Motor Control in Neurologically Impaired Individuals

Camille Georgette Marie Le Goff-Mignardot

Spinal cord injury (SCI) disrupts many essential sensorimotor and autonomic functions. Consequently, individuals with SCI can face decades with permanent disabilities. Advances in clinical management have decreased morbidity, but no clinical trial has yet demonstrated the efficacy of a repair strategy. In the past decade, Courtine lab has developed neurotechnologies that restored volitional control of locomotion in animal models of SCI. The intervention acts over two-time windows. In the short-term, the delivery of epidural electrical stimulation (EES) targeting the posterior lumbar roots with timing that mimics the natural activation of the spinal cord enables stepping in otherwise paralyzed rats. In the long-term, this targeted EES with intensive robot-assisted overground training triggers a reorganization of descending pathways that reestablished voluntary control of the paralyzed legs, even without EES. These results in animal models encouraged the transfer of these technologies and concepts to clinical applications. My contribution to this translational research program forms the core of my thesis. The first section presents a software that I developed in order to enable a comprehensive yet semi-automated analysis of kinematics and muscle activity underlying locomotor functions in humans. This toolbox allows to evaluate gait features of people with neuromotor deficits, quantify locomotor performance compared to healthy people or to monitor changes in different experimental conditions or over the time course of interventions, and automatically generate comprehensive gait reports directly understandable by scientists and clinicians. The second section introduces a paradigm shift in robotic postural assistance: the gravity-assist. We demonstrated the detrimental impact of high levels of body weight support on gravity-dependent interactions during standing and walking. We developed a gravity-assist algorithm that fine-tunes the forward and upward body weight support to reestablish these interactions based on each patientâs residual capacities. We validated the personalized gravity-assist in 30 individuals with SCI or stroke. Compared to other conditions of support, the gravity-assist enabled all the patients to improve their locomotion performance. This platform establishes refined conditions to empower and train overground locomotion in a safe yet ecological environment. The third section reports the development of targeted EES in patients with chronic SCI, and the impact of an intensive 5-month rehabilitation with gravity-assist and targeted EES on the recovery of motor functions. The key findings can be summarized as follows: We established procedures to configure targeted EES that immediately enabled voluntary control of weak or paralyzed muscles; Targeted EES boosts the residual supraspinal inputs to the lumbar spinal cord, enabling all the patients to adapt their gait to specific tasks; Locomotor performance improved during the rehabilitation; All the patients regained voluntary control over previously paralyzed muscles without EES. These combined results establish the proof-of-concept on the therapeutic potential of targeted EES and intensive, robot-assisted rehabilitation to restore locomotion after SCI. Together with similar results obtained in the US in patients with severe SCI, our findings are establishing a pathway towards the development of a viable treatment to support motor functions and improve recovery after SCI.

EPFL2019

Activating the motor system through action observation: is this an efficient approach in adults and children?

Michela Bassolino

Observing an action performed by another person to learn a new movement is a frequent experience in adult daily life, such as in sports. However, it is an especially common circumstance during the development of motor skills in childhood. Studies on healthy humans indicate that action observation induces a facilitation in the observer's motor system. This effect is supported by an action-perception matching mechanism available both in adults and in children. Because of the simplicity of action observation, it has been proposed to apply this method in clinical contexts. After a brief, non-exhaustive introduction of the essential features underlying action observation in healthy people, we review recent studies reporting beneficial effects of rehabilitative training based on a combination of action perception and execution. We focus on therapeutic interventions for patients with upper-limb motor disabilities such as adults after stroke or children with hemiplegia due to cerebral palsy. Further, we consider data from basic science demonstrating that the facilitation induced by visual perception of the action can be modulated by the combination of multimodal stimuli related to the movement (e.g. visual and acoustic action-related inputs). In line with this, we discuss possible new directions to improve basic knowledge and therapeutic applications of action observation.

Wiley-Blackwell2015

Neuroprosthetic Technologies to Evaluate and Train Leg Motor Control in Neurologically Impaired Individuals

Camille Georgette Marie Le Goff-Mignardot

EPFL2019