Dynamic Analysis of Surface Scanning for Tactile Perception

2010 ◽  
Author(s):  
Ramona Fagiani ◽  
Francesco Massi ◽  
Eric Chatelet ◽  
Yves Berthier
Keyword(s):  
Stress State ◽  
Dynamic Analysis ◽  
Bench Test ◽  
Human Hand ◽  
Global Dynamics ◽  
Clear Understanding ◽  
Frequency Range ◽  
Scanning Velocity ◽  
Vibration Spectra ◽  
The Brain

The human hand works in a perfect accord with the brain for an efficient exploration of physical world and objects perception according to man’s purposes. During the haptic sensing, the fingertip slides on a surface activating the receptors located under the skin allowing the brain to identify objects and information about their properties. In fact, in order to create the contact, the hand must exercise a force causing the fingertip to deform, generating a stress-state that contains the information on the object in contact. The information concerning the object surface is represented by the vibrations induced by the friction between the skin and the rubbed object in contact. The mechanoreceptors have the key role of transducing the stress state into an electrical impulse conveyed to the brain. Nevertheless, the vibration spectra induced by the finger/surface rubbing and the consequent activation of the mechanoreceptors on the skin were rarely investigated. A clear understanding of the mechanisms of the tactile sense is basilar for manifold applications, like the development of artificial tactile sensors for intelligent prostheses or robotic assistants, and for the ergonomics. In this context, it is fundamental to realize appropriate dynamic analysis of the signals that characterize the characteristics of the contact. In other words, it is necessary to investigate the vibration spectrum measured on the finger, in order to identify the frequency range of measured spectra (that should correspond to the expected one given by the mechanoreceptors activation frequency range [2–500 Hertz]). An experimental set-up is developed to recover the contact global dynamics by detecting the contact force and the induced vibrations; the bench test has been designed to guarantee the measurements reproducibility and, at cause of the low amplitude of the vibrations of interest, to perform measurements without introducing external noise. In particular, in this paper, the interest will be focused on the changes shown in vibration spectra with respect to variations of the scanning velocity and surface roughness characteristics.

scholarly journals Simulation and Experimental Study of the Near Field Probe in the Form of a Folded Dipole for Measuring Glucose Concentration

2021 ◽  
Vol 11 (12) ◽  
pp. 5415
Author(s):  
Aleksandr Gorst ◽  
Kseniya Zavyalova ◽  
Aleksandr Mironchev ◽  
Andrey Zapasnoy ◽  
Andrey Klokov
Keyword(s):  
Experimental Measurement ◽  
Glucose Concentration ◽  
Field Experiments ◽  
Near Field ◽  
Vector Network Analyzer ◽  
Human Hand ◽  
Physical Parameters ◽  
Network Analyzer ◽  
Frequency Range ◽  
Average Deviation

The article investigates the near-field probe of a special design to account for changes in glucose concentration. The probe is designed in such a way that it emits radiation in both directions from its plane. In this paper, it was proposed to modernize this design and consider the unidirectional emission of the probe in order to maximize the signal and reduce energy loss. We have done extensive research for both bidirectional and unidirectional probe designs. Numerical simulations and field experiments were carried out to determine different concentrations of glucose (0, 4, 5.3, 7.5 mmol/L). Numerical modeling of a unidirectional probe showed that the interaction of radiation generated by such a probe with a multilayer structure simulating a human hand showed a better result and high sensitivity compared to a bidirectional probe. Further, based on the simulation results, a phantom (physical model) of a human hand was recreated from layers with dielectric properties as close as possible to the properties of materials during simulation. The probe was constructed from a copper tube and matched both the geometric and physical parameters of the model. The experimental measurement was carried out using a vector network analyzer in the frequency range 2–10 GHz. The experimental measurement was carried out using a vector network analyzer in the frequency range 2–10 GHz for the unidirectional and bidirectional probes. Further, the results of the experiment were compared with the results of numerical simulation. According to the results of multiple experiments, it was found that the average deviation between the concentrations was 2 dB for a unidirectional probe and 0.4 dB for a bidirectional probe. Thus, the sensitivity of the unidirectional probe was 1.5 dB/(mmol/L) for the bidirectional one 0.3 dB/(mmol/L). Thus, the improved design of the near-field probe can be used to record glucose concentrations.

Abstract P717: Central Midbrain Strokes Are More Liable for Respiratory Failure Then Other Brain Stem Strokes

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Omar M Hussein ◽  
Eder Caceres ◽  
kasser saba ◽  
Hera Kamdar ◽  
khalid Sawalha ◽  
...  
Keyword(s):  
Respiratory Failure ◽  
Brain Stem ◽  
Medulla Oblongata ◽  
Multivariate Regression ◽  
Clear Understanding ◽  
Regression Analyses ◽  
Periaqueductal Grey ◽  
Stroke Registry ◽  
Adaptive Nature ◽  
The Brain

Background: Respiratory centers are known to be present in the central medulla oblongata and pons. There are multiple complex respiratory networks involving these centers. The midbrain periaqueductal grey is believed to act as a regulator of the respiratory function. The effect of brain-stem strokes on respiration remains understudied. There is a lack of clear understanding of the anatomical influence of such strokes on respiration. We attempted to identify brain-stem locations with the highest liability for respiratory failure in case of stroke. Methods: We included all ischemic and hemorrhagic brain-stem strokes from our stroke-registry between 2016 and 2018 then performed univariate/multivariate regression-analyses on variables that might predict respiratory failure and the need for intubation. The brain stem was divided into nine locations (right lateral, central, left lateral in each of the midbrain, pons, and medulla oblongata). Results: Out of 128 brain-stem strokes of different sizes and etiologies, central midbrain strokes were the only significant and independent affected location associated with respiratory failure and endotracheal intubation (coefficient= 0.1256, 95%-CI= 0.0175, 0.2338, p= 0.023). R-squared was equal to 15% when only central midbrain strokes stayed in the model. Conclusions: While one might assume that central medullary and pontine strokes have the most impact on respiration; our results show that central midbrain is the most impactful, accounting for about 15% of respiratory instability associated with brain-stem strokes. This can be explained by the adaptive nature of respiratory circuits within the medulla and pons. Central periaqueductal grey within the midbrain controls the rate and depth of respiration and might not have the same flexibility present elsewhere.

A finite element model for predicting the distribution of drugs delivered intracranially to the brain

1997 ◽  
Vol 273 (5) ◽  
pp. R1810-R1821 ◽  
Author(s):  
S. Kalyanasundaram ◽  
V. D. Calhoun ◽  
K. W. Leong
Keyword(s):  
Drug Delivery ◽  
Finite Element ◽  
Spin Echo ◽  
Interleukin 2 ◽  
Chemical Species ◽  
Transport Processes ◽  
Proton Density ◽  
Clear Understanding ◽  
Tissue Properties ◽  
The Brain

Drug therapy to the central nervous system is complicated by the presence of the blood-brain barrier. The development of new drug delivery techniques to overcome this obstacle will be aided by a clear understanding of the transport processes in the brain. A rigorous theoretical framework of the transport of drugs delivered locally to the parenchyma has been developed using the finite element method. Magnetic resonance imaging has been used to track the transport of paramagnetic contrast markers in the brain. The information obtained by postprocessing spin-echo, T1-weighted, and proton density images has been used to refine the mathematical model that includes realistic brain geometry and salient anatomic features and allows for two-dimensional transport of chemical species, including both diffusive and convective contributions. In addition, the effects of regional differences in tissue properties, ventricular boundary, and edema on the transport have been considered. The model has been used to predict transport of interleukin-2 in the brain and study the major determinants of transport, at both early and late times after drug delivery.

Design of a tribometer for investigating tactile perception

2014 ◽  
Vol 232 (6) ◽  
pp. 773-784 ◽  
Author(s):  
Francesco Massi ◽  
Eric Vittecoq ◽  
Eric Chatelet ◽  
Aurelien Saulot ◽  
Yves Berthier
Keyword(s):  
External Noise ◽  
Tactile Perception ◽  
Sliding Contact ◽  
Clear Understanding ◽  
Tactile Sense ◽  
Friction Forces ◽  
Low Amplitude ◽  
Finger Skin ◽  
The Brain ◽  
Experimental Test Bench

The understanding of the tactile perception mechanism implies the reproduction and measurement of friction forces and vibrations induced by the contact between the skin of human fingers and object surfaces. When a finger moves to scan the surface of an object, it activates the receptors located under the skin allowing the brain to identify surfaces and information about their properties. The information concerning the object surface is affected by the forces and vibrations induced by the friction between the skin and the rubbed object. The vibrations propagate in the finger skin and are converted into electric impulses sent to the brain by the mechanoreceptors. Because of the low amplitude of the induced vibrations, it results quite hard to reproduce the tactile surface scanning and measuring it without affecting measurements by external noise coming from the experimental test-bench. In fact the reproduction of the sliding contact between two surfaces implies the relative motion between them, which is obtained by appropriate mechanisms having a more or less complicated kinematics and including several sliding surfaces (bearings, sliders, etc.). It results quite difficult to distinguish between the vibrations coming from the reproduced sliding and the parasitic noise coming from the other sliding contact pairs. This paper presents the design and validation of a tribometer, named TRIBOTOUCH, allowing for reproducing and measuring friction forces and friction induced vibrations that are basilar for a clear understanding of the mechanisms of the tactile sense.

scholarly journals Reflections on the Constraints and Opportunities in Therapy in Rett Syndrome

2006 ◽  
Vol 6 ◽  
pp. 992-997 ◽  
Author(s):  
Alison M. Kerr
Keyword(s):  
Quality Of Life ◽  
Neural Networks ◽  
Rett Syndrome ◽  
Clear Understanding ◽  
Research Experience ◽  
Hormonal Responses ◽  
Physical Limitations ◽  
The Brain ◽  
Insight Into

More than 20 years of clinical and research experience with affected people in the British Isles has provided insight into particular challenges for therapists, educators, or parents wishing to facilitate learning and to support the development of skills in people with Rett syndrome. This paper considers the challenges in two groups: those due to constraints imposed by the disabilities associated with the disorder and those stemming from the opportunities, often masked by the disorder, allowing the development of skills that depend on less-affected areas of the brain. Because the disorder interferes with the synaptic links between neurones, the functions of the brain that are most dependent on complex neural networks are the most profoundly affected. These functions include speech, memory, learning, generation of ideas, and the planning of fine movements, especially those of the hands. In contrast, spontaneous emotional and hormonal responses appear relatively intact. Whereas failure to appreciate the physical limitations of the disease leads to frustration for therapist and client alike, a clear understanding of the better-preserved areas of competence offers avenues for real progress in learning, the building of satisfying relationships, and achievement of a quality of life.

scholarly journals The joy of sharing knowledge: But what if there is no knowledge to share? A critical reflection on human capacity building in Africa

2007 ◽  
Vol 7 ◽  
pp. 18-28
Author(s):  
Johannes J Britz
Keyword(s):  
Research And Development ◽  
Capacity Building ◽  
Capacity Development ◽  
Clear Understanding ◽  
Political Will ◽  
Current Trends ◽  
Long Run ◽  
Starting Point ◽  
Human Capacity ◽  
The Brain

This article focuses on the current trends and initiatives in human capacity building in Africa. It takes as it starting point that human capacity development is essential for Africa to become an information and know-ledge society and therefore an equal partner in the global sharing of knowledge. Four knowledge areas are identified and discussed. These are education, research and development, brain drain and information and documentation drain. The paper concludes that there is a clear understanding in Africa that its future lies with education and that most African leaders have a strong political will to invest in human capacity building on the continent. It is also clear that much has been done, particularly primary education. Africa will most defi-nitely benefit from this in the long run. Problem areas remain however. These are in the needed growth of research and development and how to address the brain and information drain phenomena.

scholarly journals Low Frequency Noise Remove from EEG Signal

2020 ◽  
Vol 9 (1) ◽  
pp. 1510-1513
Keyword(s):  
Human Brain ◽  
Random Noise ◽  
Low Frequency ◽  
Frequency Noise ◽  
Eeg Signal ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Average Value ◽  
Different Types ◽  
The Brain

The electrical activity of the brain recorded by EEG which used to detect different types of diseases and disorders of the human brain. There is contained a large amount of random noise present during EEG recording, such as artifacts and baseline changes. These noises affect the low -frequency range of the EEG signal. These artifacts hiding some valuable information during analyzing of the EEG signal. In this paper we used the FIR filter for removing low -frequency noise(<1Hz) from the EEG signal. The performance is measured by calculating the SNR and the RMSE. We obtained RMSE average value from the test is 0.08 and the SNR value at frequency(<1Hz) is 0.0190.

scholarly journals Pre-stimulus phase and amplitude regulation of phase-locked responses are maximized in the critical state

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Arthur-Ervin Avramiea ◽  
Richard Hardstone ◽  
Jan-Matthis Lueckmann ◽  
Jan Bím ◽  
Huibert D Mansvelder ◽  
...  
Keyword(s):  
Computational Model ◽  
Critical State ◽  
Global Dynamics ◽  
Critical Dynamics ◽  
Neuronal Responses ◽  
Scale Free ◽  
Stimulus Response ◽  
Functional States ◽  
The Brain

Understanding why identical stimuli give differing neuronal responses and percepts is a central challenge in research on attention and consciousness. Ongoing oscillations reflect functional states that bias processing of incoming signals through amplitude and phase. It is not known, however, whether the effect of phase or amplitude on stimulus processing depends on the long-term global dynamics of the networks generating the oscillations. Here, we show, using a computational model, that the ability of networks to regulate stimulus response based on pre-stimulus activity requires near-critical dynamics—a dynamical state that emerges from networks with balanced excitation and inhibition, and that is characterized by scale-free fluctuations. We also find that networks exhibiting critical oscillations produce differing responses to the largest range of stimulus intensities. Thus, the brain may bring its dynamics close to the critical state whenever such network versatility is required.

Crosstalk between Microglia and Neurons in Neurotrauma: An Overview of the Underlying Mechanisms

2021 ◽  
Vol 19 ◽  
Author(s):  
Muhammad Ali Haidar ◽  
Stanley Ibeh ◽  
Zaynab Shakkour ◽  
Mohammad Amine Reslan ◽  
Judith Nwaiwu ◽  
...  
Keyword(s):  
Brain Injury ◽  
Microglial Activation ◽  
Trauma Treatment ◽  
Cell Contact ◽  
Clear Understanding ◽  
Neuroinflammatory Response ◽  
Proinflammatory Responses ◽  
Underlying Mechanisms ◽  
The Brain ◽  
Cns Anomalies

: Microglia are the resident immune cells of the brain and play a crucial role in housekeeping and maintaining homeostasis of the brain microenvironment. Upon injury or disease, microglial cells become activated, at least partly, via signals initiated by injured neurons. Activated microglia, thereby, contribute to both neuroprotection and neuroinflammation. However, sustained microglial activation initiates a chronic neuroinflammatory response which can disturb neuronal health and disrupt communications between neurons and microglia. Thus, microglia-neuron crosstalk is critical in a healthy brain as well as during states of injury or disease. As most studies focus on how neurons and microglia act in isolation during neurotrauma, there is a need to understand the interplay between these cells in brain pathophysiology. This review highlights how neurons and microglia reciprocally communicate under physiological conditions and during brain injury and disease. Furthermore, the modes of microglia-neuron communication are exposed, focusing on cell-contact dependent signaling and communication by the secretion of soluble factors like cytokines and growth factors. In addition, how microglia-neuron interactions could exert either beneficial neurotrophic effects or pathologic proinflammatory responses are discussed. We further explore how aberrations in microglia-neuron crosstalk may be involved in central nervous system (CNS) anomalies, namely: traumatic brain injury (TBI), neurodegeneration, and ischemic stroke. A clear understanding of how the microglia-neuron crosstalk contributes to the pathogenesis of brain pathologies may offer novel therapeutic avenues of brain trauma treatment.

Sign in / Sign up

Export Citation Format

Share Document