Système sensoriel

Résumé

Un système sensoriel est une partie du système nerveux responsable de la sensation. Il regroupe les récepteurs sensoriels, les voies nerveuses, et les parties du cerveau responsables du traitement de l'information sensorielle. L'ensemble des systèmes sensoriels se divisent en sensibilité générale ou somesthésie et en sens dits spécifiques : la vision, l'odorat, le goût, l'ouïe et le toucher. Il existe sept sens : les cinq sens vu ci-dessus (vision, odorat, goût, ouïe et toucher), ainsi que le système vestibulaire et le système proprioceptif. Certains scientifiques parlent également d'un huitième sens, le système intéroceptif. Fonctions Traitement sensoriel L'expression Traitement sensoriel a plusieurs sens dans la littérature scientifique. Elle peut décrire, selon le contexte :

l'acuité d'un sens (ex : acuité visuelle, acuité auditive), correspondant à un spectre qui s'étend de l'absence totale de perception (ex : surdité totale) à une herpersensibilité,

Source officielle

https://fr.wikipedia.org/wiki/Syst%C3%A8me_sensoriel

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Concepts associés (68)

vignette|Les cinq sens d'après Aristote, représentés par leurs organes sensoriels inhérents : oreilles, yeux, langue, nez, peau. Du point de vue de la physiologie, les sens sont les systèmes sensorie

thumb|Le système nerveux humain. Le système nerveux (ou système neuronal) est un système biologique animal responsable de la coordination des actions avec l'environnement extérieur et de la communica

vignette|Cerveau d'un chimpanzé. Le cerveau est le principal organe du système nerveux des animaux bilatériens. Ce terme tient du langage courant (non scientifique) et chez les chordés, comme les hum

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Biological motor control is versatile and efficient. Muscles are flexible and undergo continuous changes requiring distributed adaptive control mechanisms. How proprioception solves this problem in the brain is unknown. Here we pursue a task-driven modeling approach that has provided important insights into other sensory systems. However, unlike for vision and audition where large annotated datasets of raw images or sound are readily available, data of relevant proprioceptive stimuli are not. We generated a large-scale dataset of human arm trajectories as the hand is tracing the alphabet in 3D space, then using a musculoskeletal model derived the spindle firing rates during these movements. We propose an action recognition task that allows training of hierarchical models to classify the character identity from the spindle firing patterns. Artificial neural networks could robustly solve this task, and the networks’ units show directional movement tuning akin to neurons in the primate somatosensory cortex. The same architectures with random weights also show similar kinematic feature tuning but do not reproduce the diversity of preferred directional tuning nor do they have invariant tuning across 3D space. Taken together our model is the first to link tuning properties in the proprioceptive system to the behavioral level.

Neuroscience2020

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Neuroprosthetic systems are designed to interface with the nervous system, for the replacement or restoration of damaged functions in the motor and/or sensory systems. In order to have an efficient communication with the nervous tissue leading to optimized clinical outcomes, achieving neural stimulation with high selectivity is essential. This thesis aims at finding technological routes to enable spatial, structural and cell-type selective surface neuromodulation using electrical and optogenetic stimulation and to validate them in in vivo models. Thin and conformable electrode arrays enable close contact with the target tissue, thereby leading to minimal distances with the target neurons and maximal spatial selectivity. Flexible polymer technologies based on polyimide (PI) are used to design thin (< 10 ÎŒm thick) electrode arrays with small feature size (< 100 ÎŒm), resulting in miniaturized conformable arrays for surface stimulation. PEDOT conducting polymer coatings are used on the miniaturized electrical stimulation sites (100 ÎŒm diameter) to improve their charge injection properties. This implant is used for auditory brainstem stimulation in a rat model, and is shown to generate robust activation of the auditory system. Analysis of the multiunit recordings obtained from the inferior colliculus (IC), an auditory structure of the midbrain, led to the identification of different phases in the responses, with various frequency tuning properties. The stimulation configuration is shown to influence the tonotopic organisation of the frequency-tuned responses. Bipolar stimulation with small interelectrode distances (400 ÎŒm) is shown to generate responses that are more frequency-selective than with larger interelectrode distances (800 ÎŒm). The orientation of the electrode pair and the waveformof stimulation current are also shown to influence the response properties. An updated design of the clinical auditory brainstem implant(ABI) is then proposed, integrating higher electrode density and guidelines for a more tissue-conformal format. The main steps in the road towards improvement of ABI outcomes are then discussed, with proposed changes in the stimulation protocol and electrode array in parallel. Another approach to cell-specific neuromodulation is the implementation of optogenetics. This requires not only genetic engineering of the neurons but also the manufacturing of implantable light-emitting devices. Here, we introduce a fabrication process for the integration of thin (50 ÎŒm) LEDs into a polyimide-based device. A proof-of-concept in vivo study shows that stimulation of the spinal cord of a mouse model generates robust EMG responses in both legs over the course of several weeks. The walking integrity is confirmed, showing the absence of functional damages to the spinal cord. These results show that the presented LED array can provide a way of stimulating key elements of the locomotor neural circuitry, potentially leading to a greater understanding of the role of each neuronal subtypes in the spinal cord. Through the applications of ABI and spinal cord stimulation, this thesis thus highlights the importance and potential use of specifically tailored technologies enabling selective surface stimulation of the nervous system.

EPFL2017

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A Whisker Stimulator For Sensory System Research

Reymond Clavel, Raphael Holzer, Madeleine Kägi

L'outil, le "whisker stimulator" doit permettre de simuler les mouvements naturels des moustaches tout en mesurant simultanément l'activité cérébrale de la souris. Le cahier de charges demande un stimulateur pouvant faire une impulsion de 100um de déplacement à 1kHz. Dans le cadre de ce travail, différentes solutions sont recherchées. Le choix de l'actionneur est un piézotube à quatre segments.

2005

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EPFL2017