scholarly journals Evaluating the Influence of Motor Control on Selective Attention through a Stochastic Model: The Paradigm of Motor Control Dysfunction in Cerebellar Patient

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Giacomo Veneri ◽  
Antonio Federico ◽  
Alessandra Rufa
Keyword(s):  
Motor Control ◽  
Selective Attention ◽  
Stochastic Model ◽  
Motor System ◽  
Late Onset ◽  
Intrinsic Noise ◽  
Cognitive Mechanisms ◽  
Noise Sources ◽  
Energy Functions ◽  
New Approach

Attention allows us to selectively process the vast amount of information with which we are confronted, prioritizing some aspects of information and ignoring others by focusing on a certain location or aspect of the visual scene. Selective attention is guided by two cognitive mechanisms: saliency of the image (bottom up) and endogenous mechanisms (top down). These two mechanisms interact to direct attention and plan eye movements; then, the movement profile is sent to the motor system, which must constantly update the command needed to produce the desired eye movement. A new approach is described here to study how the eye motor control could influence this selection mechanism in clinical behavior: two groups of patients (SCA2 and late onset cerebellar ataxia LOCA) with well-known problems of motor control were studied; patients performed a cognitively demanding task; the results were compared to a stochastic model based on Monte Carlo simulations and a group of healthy subjects. The analytical procedure evaluated some energy functions for understanding the process. The implemented model suggested that patients performed an optimal visual search, reducing intrinsic noise sources. Our findings theorize a strict correlation between the “optimal motor system” and the “optimal stimulus encoders.”

scholarly journals Diabetes Mellitus-Related Dysfunction of the Motor System

2020 ◽  
Vol 21 (20) ◽  
pp. 7485
Author(s):  
Ken Muramatsu
Keyword(s):  
Motor Control ◽  
Motor Neurons ◽  
Motor System ◽  
Corticospinal Tract ◽  
Experimental Studies ◽  
Sensory System ◽  
Treatment Strategies ◽  
Motor Deficits ◽  
New Perspective ◽  
The Brain

Although motor deficits in humans with diabetic neuropathy have been extensively researched, its effect on the motor system is thought to be lesser than that on the sensory system. Therefore, motor deficits are considered to be only due to sensory and muscle impairment. However, recent clinical and experimental studies have revealed that the brain and spinal cord, which are involved in the motor control of voluntary movement, are also affected by diabetes. This review focuses on the most important systems for voluntary motor control, mainly the cortico-muscular pathways, such as corticospinal tract and spinal motor neuron abnormalities. Specifically, axonal damage characterized by the proximodistal phenotype occurs in the corticospinal tract and motor neurons with long axons, and the transmission of motor commands from the brain to the muscles is impaired. These findings provide a new perspective to explain motor deficits in humans with diabetes. Finally, pharmacological and non-pharmacological treatment strategies for these disorders are presented.

scholarly journals Restricted and repetitive behaviors in autism spectrum disorders: The relationship of attention and motor deficits

2013 ◽  
Vol 25 (3) ◽  
pp. 773-784 ◽  
Author(s):  
Susan M. Ravizza ◽  
Marjorie Solomon ◽  
Richard B. Ivry ◽  
Cameron S. Carter
Keyword(s):  
Autism Spectrum Disorders ◽  
Motor Control ◽  
Motor System ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Motor Deficits ◽  
Attentional Orienting ◽  
Restricted And Repetitive Behaviors ◽  
Spectrum Disorders ◽  
The Relationship

AbstractRestricted and repetitive behaviors (RRBs) are hallmark symptoms of autism spectrum disorders (ASDs); however, it has proven difficult to understand the mechanisms underlying these behaviors. One hypothesis suggests that RRBs are the result of a core deficit in attention. Alternatively, abnormalities of the motor system may constitute the central mechanism underlying RRBs, given motor deficits observed in ASDs. In this experiment, we investigated the etiology of RRBs and the relationship between attention and motor deficits. Movement impairments (a) may be indirectly related to attention deficits, (b) may result from a shared compromised process, or (c) may be independent. Twenty-two adolescents with ASD and 20 typically developing participants performed a spatial attention task. Movement impairments were assessed with a rhythmic tapping task. Attentional orienting and motor control were found to be related and supported the hypothesis that these impairments in ASD arise from a shared process. In contrast, measures of attention switching and motor control were found to be independent. Stereotyped behaviors, as assessed by parental ratings, were related more to the degree of motor impairment than to deficits of attention. These results suggest that both attentional orienting deficits and stereotyped RRBs are related to a compromised motor system.

scholarly journals Bias-dependence of FET intrinsic noise sources, determined with a quasi-2D model

2003 ◽  
Vol 39 (4) ◽  
pp. 317-319 ◽  
Author(s):  
A. Lázaro ◽  
M. C. Maya ◽  
L. Pradell
Keyword(s):  
Intrinsic Noise ◽  
Noise Sources ◽  
2D Model

scholarly journals Task-dependent switching of feedback controllers

2021 ◽  
Author(s):  
Justinas Česonis ◽  
David W. Franklin
Keyword(s):  
Motor Control ◽  
Feedback Control ◽  
Motor System ◽  
The Other ◽  
Contextual Cues ◽  
Feedback Controllers ◽  
Human Motor Control ◽  
Mixed Schedule ◽  
Human Motor ◽  
Human Participants

AbstractThe separation of distinct motor memories by contextual cues is a well known and well studied phenomenon of feedforward human motor control. However, there is no clear evidence of such context-induced separation in feedback control. Here we test both experimentally and computationally if context-dependent switching of feedback controllers is possible in the human motor system. Specifically, we probe visuomotor feedback responses of our human participants in two different tasks – stop and hit – and under two different schedules. The first, blocked schedule, is used to measure the behaviour of stop and hit controllers in isolation, showing that it can only be described by two independent controllers with two different sets of control gains. The second, mixed schedule, is then used to compare how such behaviour evolves when participants regularly switch from one task to the other. Our results support our hypothesis that there is contextual switching of feedback controllers, further extending the accumulating evidence of shared features between feedforward and feedback control.

scholarly journals Modeling the Role of Sensory Feedback in Speech Motor Control and Learning

2019 ◽  
Vol 62 (8S) ◽  
pp. 2963-2985 ◽  
Author(s):  
Benjamin Parrell ◽  
John Houde
Keyword(s):  
Motor Control ◽  
Motor System ◽  
Sensory Feedback ◽  
Computational Models ◽  
State Feedback Control ◽  
Speech Motor Control ◽  
Control Feedback ◽  
Motor Production ◽  
Speech Motor

Purpose While the speech motor system is sensitive to feedback perturbations, sensory feedback does not seem to be critical to speech motor production. How the speech motor system is able to be so flexible in its use of sensory feedback remains an open question. Method We draw on evidence from a variety of disciplines to summarize current understanding of the sensory systems' role in speech motor control, including both online control and motor learning. We focus particularly on computational models of speech motor control that incorporate sensory feedback, as these models provide clear encapsulations of different theories of sensory systems' function in speech production. These computational models include the well-established directions into velocities of articulators model and computational models that we have been developing in our labs based on the domain-general theory of state feedback control (feedback aware control of tasks in speech model). Results After establishing the architecture of the models, we show that both the directions into velocities of articulators and state feedback control/feedback aware control of tasks models can replicate key behaviors related to sensory feedback in the speech motor system. Although the models agree on many points, the underlying architecture of the 2 models differs in a few key ways, leading to different predictions in certain areas. We cover key disagreements between the models to show the limits of our current understanding and point toward areas where future experimental studies can resolve these questions. Conclusions Understanding the role of sensory information in the speech motor system is critical to understanding speech motor production and sensorimotor learning in healthy speakers as well as in disordered populations. Computational models, with their concrete implementations and testable predictions, are an important tool to understand this process. Comparison of different models can highlight areas of agreement and disagreement in the field and point toward future experiments to resolve important outstanding questions about the speech motor control system.

scholarly journals Joint Effect of Heterogeneous Intrinsic Noise Sources on Instability of MEMS Resonators

2016 ◽  
Vol 19 (2) ◽  
pp. 59
Author(s):  
Olga Jakšić ◽  
Ivana Jokić ◽  
Miloš Frantlović ◽  
Danijela Randjelović ◽  
Dragan Tanasković ◽  
...  
Keyword(s):  
Phase Noise ◽  
Noise Analysis ◽  
Intrinsic Noise ◽  
Noise Spectrum ◽  
Joint Effect ◽  
Noise Sources ◽  
Mems Resonators ◽  
Micro Resonator ◽  
Micro Cantilever ◽  
Nyquist Noise

This article's focus is on the numerical estimation of the overall instability of microelectromechanical-system-based (MEMS) resonators, caused by intrinsic noise mechanisms that are different in nature (electrical, mechanical or chemical). Heterogeneous intrinsic noise sources in MEMS resonators that have been addressed here are Johnson–Nyquist noise, 1/f noise, noise caused by temperature fluctuations and adsorptiondesorption induced noise. Their models are given first (based on analytical modeling or based on empirical expressions with experimentally obtained parameters). Then it is shown how each one contributes to the phase noise, a unique figure of merit of resonators instability. Material dependent constants  and knee position in noise spectrum, needed for empirical formulae referring to 1/f noise, have been obtained experimentally, by measurements of noise of MEMS components produced in the Centre of Microelectronic Technologies of the Institute of Chemistry, Technology and Metallurgy in Belgrade. According to these measurements,  varies in the range from 0.776.10-4 to 2.26.10-4 and cut off frequency for 1/f noise varies from 147 Hz to 1 kHz. The determined values are then used for the modeling of micro-resonator phase noise with electrical origin and overall phase noise of a micro-resonator. Numerical example for calculation of overall phase noise is given for a micro-cantilever, produced by the same technology as measured components. The outlined noise analysis can be easily extended and applied to noise analysis of MEMS resonator of an arbitrary shape.

A Reticulothalamic System Mediating Proprioceptive Attention and Tremor in Man

Neurosurgery ◽  
1979 ◽  
Vol 4 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Francisco Velasco ◽  
Marcos Velasco
Keyword(s):  
Electrical Stimulation ◽  
Motor Control ◽  
Selective Attention ◽  
Evoked Potentials ◽  
Motor Responses ◽  
Sensory Deficits ◽  
Multiunit Activity ◽  
Proprioceptive Stimulation ◽  
Complex Motor ◽  
Lemniscal System

Abstract This report describes the electrophysiological characteristics of thalamic and subthalamic targets used to control tremor. In these targets exploratory electrodes recorded one or more of the following events. Electrical stimulation produced enhancement of tremor or other complex motor responses. Somatic evoked potentials (SEPs) induced by proprioceptive stimulation showed only late components, the amplitudes of which changed in various attentive situations. Multiunit activity showed spontaneous 3- to 6-Hz rhythmic bursts. And a lesion produced neglect of contralateral extremities and an ipsilateral decrease of scalp-recorded SEP late components. In contrast, in the areas located immediately posterior and dorsal, electrical stimulation produced contralateral paresthesias. Early components of SEPs could be recorded, as were rhythmic bursts of multiunit activity after the occurrence of peripheral tremor. Lesions produced sensory deficits in the contralateral extremities and ipsilateral blocking of all components of scalp SEPs. The latter areas are identified as the lemniscal system, but the former seem to be extralemniscal. Their electrophysiological characteristics suggest that they are probably involved in the process of selective attention and motor control

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