Absence of Gamma-Range Corticomuscular Coherence During Dynamic Force in a Deafferented Patient

2008 ◽  
Vol 99 (4) ◽  
pp. 1906-1916 ◽  
Author(s):  
Luis Patino ◽  
Wolfgang Omlor ◽  
Vihren Chakarov ◽  
Marie-Claude Hepp-Reymond ◽  
Rumyana Kristeva
Keyword(s):  
Motor Command ◽  
Gamma Band ◽  
Afferent Feedback ◽  
Dynamic Force ◽  
Proprioceptive Information ◽  
Corticomuscular Coherence ◽  
Visuomotor Task ◽  
Gamma Range ◽  
Dynamic Forces ◽  
And Control

Recently, we studied corticomuscular coherence (CMC) in a visuomotor task and showed for the first time gamma-range (30–45 Hz) CMC during isometric compensation of a periodically modulated dynamic force. We speculated that for the control of such forces, the sensorimotor system resonates at gamma-range frequencies to rapidly integrate the visual and proprioceptive information and produce the appropriate motor command. In this study, we tested the role of the proprioceptive afferent feedback on gamma-range CMC by comparing the deafferented patient GL to six age- and sex-matched subjects during the performance of a visuomotor force task consisting of isometric compensation of static and dynamic forces applied on the finger. Patient GL presented no significant gamma-band CMC during dynamic force. Instead, she had only beta-range CMC as in the static force condition; concurrently, her performance was significantly worse than that of the controls in both conditions. This gives support to the conclusions of our previous paper and suggests that proprioceptive information is mandatory in the genesis of gamma-band CMC during the generation and control of dynamic forces.

Gamma-range corticomuscular coherence during dynamic force output

NeuroImage ◽  
2007 ◽  
Vol 34 (3) ◽  
pp. 1191-1198 ◽  
Author(s):  
Wolfgang Omlor ◽  
Luis Patino ◽  
Marie-Claude Hepp-Reymond ◽  
Rumyana Kristeva
Keyword(s):  
Dynamic Force ◽  
Force Output ◽  
Corticomuscular Coherence ◽  
Gamma Range

scholarly journals A Multimode Transverse Dynamic Force Microscope—Design, Identification, and Control

2020 ◽  
Vol 67 (6) ◽  
pp. 4729-4740
Author(s):  
Kaiqiang Zhang ◽  
Toshiaki Hatano ◽  
Guido Herrmann ◽  
Massimo Antognozzi ◽  
Christopher Edwards ◽  
...  
Keyword(s):  
Dynamic Force ◽  
Transverse Dynamic ◽  
And Control ◽  
Microscope Design

The strength of the corticospinal coherence depends on the predictability of modulated isometric forces

2013 ◽  
Vol 109 (6) ◽  
pp. 1579-1588 ◽  
Author(s):  
Ignacio Mendez-Balbuena ◽  
Jose Raul Naranjo ◽  
Xi Wang ◽  
Agnieska Andrykiewicz ◽  
Frank Huethe ◽  
...  
Keyword(s):  
Sensory Feedback ◽  
Muscle Activation ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Visuomotor Task ◽  
Gamma Range ◽  
Cortical Motor ◽  
Contralateral Hand ◽  
Hand Motor Area ◽  
Isometric Forces

Isometric compensation of predictably frequency-modulated low forces is associated with corticomuscular coherence (CMC) in beta and low gamma range. It remains unclear how the CMC is influenced by unpredictably modulated forces, which create a mismatch between expected and actual sensory feedback. We recorded electroencephalography from the contralateral hand motor area, electromyography (EMG), and the motor performance of 16 subjects during a visuomotor task in which they had to isometrically compensate target forces at 8% of the maximum voluntary contraction with their right index finger. The modulated forces were presented with predictable or unpredictable frequencies. We calculated the CMC, the cortical motor alpha-, beta-, and gamma-range spectral powers (SP), and the task-related desynchronization (TRD), as well as the EMG SP and the performance. We found that in the unpredictable condition the CMC was significantly lower and associated with lower cortical motor SP, stronger TRD, higher EMG SP, and worse performance. The findings suggest that due to the mismatch between predicted and actual sensory feedback leading to higher computational load and less stationary motor state, the unpredictable modulation of the force leads to a decrease in corticospinal synchrony, an increase in cortical and muscle activation, and a worse performance.

BINDING AND SEGMENTATION VIA A NEURAL MASS MODEL TRAINED WITH HEBBIAN AND ANTI-HEBBIAN MECHANISMS

2012 ◽  
Vol 22 (02) ◽  
pp. 1250003 ◽  
Author(s):  
FILIPPO CONA ◽  
MELISSA ZAVAGLIA ◽  
MAURO URSINO
Keyword(s):  
Pyramidal Neurons ◽  
Memory Task ◽  
External Input ◽  
Gamma Band ◽  
Neural Mass Model ◽  
Excitatory Synapses ◽  
Multiple Objects ◽  
Mass Model ◽  
Gamma Range ◽  
Neural Mass

Synchronization of neural activity in the gamma band, modulated by a slower theta rhythm, is assumed to play a significant role in binding and segmentation of multiple objects. In the present work, a recent neural mass model of a single cortical column is used to analyze the synaptic mechanisms which can warrant synchronization and desynchronization of cortical columns, during an autoassociation memory task. The model considers two distinct layers communicating via feedforward connections. The first layer receives the external input and works as an autoassociative network in the theta band, to recover a previously memorized object from incomplete information. The second realizes segmentation of different objects in the gamma band. To this end, units within both layers are connected with synapses trained on the basis of previous experience to store objects. The main model assumptions are: (i) recovery of incomplete objects is realized by excitatory synapses from pyramidal to pyramidal neurons in the same object; (ii) binding in the gamma range is realized by excitatory synapses from pyramidal neurons to fast inhibitory interneurons in the same object. These synapses (both at points i and ii) have a few ms dynamics and are trained with a Hebbian mechanism. (iii) Segmentation is realized with faster AMPA synapses, with rise times smaller than 1 ms, trained with an anti-Hebbian mechanism. Results show that the model, with the previous assumptions, can correctly reconstruct and segment three simultaneous objects, starting from incomplete knowledge. Segmentation of more objects is possible but requires an increased ratio between the theta and gamma periods.

scholarly journals Motor-induced Suppression of the Auditory Cortex

2009 ◽  
Vol 21 (4) ◽  
pp. 791-802 ◽  
Author(s):  
Sheye O. Aliu ◽  
John F. Houde ◽  
Srikantan S. Nagarajan
Keyword(s):  
Auditory Cortex ◽  
Auditory System ◽  
Somatosensory System ◽  
Motor Command ◽  
Stimulus Onset ◽  
Button Press ◽  
Motor Processing ◽  
Sensory Motor ◽  
Sensory Responses ◽  
And Control

Sensory responses to stimuli that are triggered by a self-initiated motor act are suppressed when compared with the response to the same stimuli triggered externally, a phenomenon referred to as motor-induced suppression (MIS) of sensory cortical feedback. Studies in the somatosensory system suggest that such suppression might be sensitive to delays between the motor act and the stimulus onset, and a recent study in the auditory system suggests that such MIS develops rapidly. In three MEG experiments, we characterize the properties of MIS by examining the M100 response from the auditory cortex to a simple tone triggered by a button press. In Experiment 1, we found that MIS develops for zero delays but does not generalize to nonzero delays. In Experiment 2, we found that MIS developed for 100-msec delays within 300 trials and occurs in excess of auditory habituation. In Experiment 3, we found that unlike MIS for zero delays, MIS for nonzero delays does not exhibit sensitivity to sensory, delay, or motor-command changes. These results are discussed in relation to suppression to self-produced speech and a general model of sensory motor processing and control.

Visual Grouping and the Focusing of Attention Induce Gamma-band Oscillations at Different Frequencies in Human Magnetoencephalogram Signals

2006 ◽  
Vol 18 (11) ◽  
pp. 1850-1862 ◽  
Author(s):  
Juan R. Vidal ◽  
Maximilien Chaumon ◽  
J. Kevin O'Regan ◽  
Catherine Tallon-Baudry
Keyword(s):  
Short Term Memory ◽  
Implementation Process ◽  
Visual Display ◽  
Gamma Oscillations ◽  
Gamma Band ◽  
Visual Grouping ◽  
Gamma Range ◽  
High Gamma ◽  
The One ◽  
Attentional Filter

Neural oscillatory synchrony could implement grouping processes, act as an attentional filter, or foster the storage of information in short-term memory. Do these findings indicate that oscillatory synchrony is an unspecific epiphenomenon occurring in any demanding task, or that oscillatory synchrony is a fundamental mechanism involved whenever neural cooperation is requested? If the latter hypothesis is true, then oscillatory synchrony should be specific, with distinct visual processes eliciting different types of oscillations. We recorded magnetoencephalogram (MEG) signals while manipulating the grouping properties of a visual display on the one hand, and the focusing of attention to memorize part of this display on the other hand. Grouping-related gamma oscillations were present in all conditions but modulated by the grouping properties of the stimulus (one or two groups) in the high gamma-band (70–120 Hz) at central occipital locations. Attention-related gamma oscillations appeared as an additional component whenever attentional focusing was requested in the low gamma-band (44–66 Hz) at parietal locations. Our results thus reveal the existence of a functional specialization in the gamma range, with grouping-related oscillations showing up at higher frequencies than attention-related oscillations. The pattern of oscillatory synchrony is thus specific of the visual process it is associated with. Our results further suggest that both grouping processes and focused attention rely on a common implementation process, namely, gamma-band oscillatory synchrony, a finding that could account for the fact that coherent percepts are more likely to catch attention than incoherent ones.

A New Force-Displacement Metrology for Keyboards

1997 ◽  
Vol 41 (1) ◽  
pp. 637-641
Author(s):  
Gary S. Olacsi ◽  
Robert J. Beaton
Keyword(s):  
Displacement Function ◽  
Dynamic Force ◽  
Ergonomic Design ◽  
The Past ◽  
Design Attributes ◽  
Dynamic Forces ◽  
Force Components ◽  
Force Displacement

The ergonomic design of computer keyboards has been a popular topic of research during the past decade. Much work has focused on assessing design attributes of keyboards that affect their subjective “feel” during typing tasks. One common measure used for this purpose has been the force-displacement function, which characterizes the force required to displace a key to various positions within its travel range. Unfortunately, keyboard manufacturers and researchers have used stepped force-displacement techniques that quantify the holding force needed to maintain a key in a selected displacement position, but it does not assess the dynamic forces experienced at a user's fingertips while typing. This paper introduces a continuous force-displacement technique that measures dynamic force components.

scholarly journals The visual cortex produces a signal in the gamma band in response to broadband visual flicker

2021 ◽  
Author(s):  
Alexander Zhigalov ◽  
Katharina Duecker ◽  
Ole Jensen
Keyword(s):  
Visual Cortex ◽  
Visual Stimulation ◽  
Gamma Oscillations ◽  
Early Response ◽  
Dominant Frequency ◽  
Gamma Band ◽  
Input Current ◽  
Alpha Band ◽  
Constant Input ◽  
Gamma Range

AbstractThe aim of this study is to uncover the network dynamics of the human visual cortex by driving it with a broadband random visual flicker. We here applied a broadband flicker (1–720 Hz) while measuring the MEG and then estimated the temporal response function (TRF) between the visual input and the MEG response. This TRF revealed an early response in the 40–60 Hz gamma range as well as in the 8–12 Hz alpha band. While the gamma band response is novel, the latter has been termed the alpha band perceptual echo. The gamma echo preceded the alpha perceptual echo. The dominant frequency of the gamma echo was subject-specific thereby reflecting the individual dynamical properties of the early visual cortex. To understand the neuronal mechanisms generating the gamma echo, we implemented a pyramidal-interneuron gamma (PING) model that produces gamma oscillations in the presence of constant input currents. Applying a broadband input current mimicking the visual stimulation allowed us to estimate TRF between the input current and the population response (akin to the local field potentials). The TRF revealed a gamma echo that was similar to the one we observed in the MEG data. Our results suggest that the visual gamma echo can be explained by the dynamics of the PING model even in the absence of sustained gamma oscillations.

An Experimental Study of Cutting Forces in High-Speed End Milling and Implications for Dynamic Force Modeling

2005 ◽  
Vol 127 (2) ◽  
pp. 251-261 ◽  
Author(s):  
P. T. Mativenga ◽  
K. K. B. Hon
Keyword(s):  
Frequency Domain ◽  
Cutting Forces ◽  
High Speed ◽  
End Milling ◽  
Dynamic Force ◽  
High Speed Machining ◽  
Time Data ◽  
Dynamic Forces ◽  
Milling Forces ◽  
Aisi H13 Tool Steel

The characteristics of high-speed machining (HSM) dynamic milling forces was investigated. Recent studies in chip segmentation are discussed. A Mikron 700 High-Speed Machining Center was used in the end-milling of AISI H13 tool steel using PVD TiN coated two flute micrograin carbide tools. Dynamic force signals were studied using a real-time data acquisition system for spindle speeds from 3,750 to 31,500 rpm for a 6 mm dia tool. Frequency domain studies were also carried out for a larger tool of 12 mm dia for spindle speeds between 10,000 and 40,000 rpm. The trend and frequency domain aspects of the dynamic forces were evaluated and discussed. The fundamental concept of modeling cutting forces based on chip morphology is revisited. A new basis for modeling dynamic forces from the static component and harmonic contributions is presented. This approach for modeling the dynamic HSM force signal accounts for secondary harmonics.

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