The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Philippe Mailly - One of the best experts on this subject based on the ideXlab platform.
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characterization of the spinal nucleus of the bulbocavernosus Neuromuscular System in male mice lacking androgen receptor in the nervous System
Endocrinology, 2012Co-Authors: Kalina Raskin, Clarisse Marieluce, M C Picot, Veronique Bernard, Philippe MaillyAbstract:Motoneurons in the spinal nucleus of the bulbocavernosus (SNB) and their target bulbocavernosus (BC) and levator ani (LA) muscles play a role in male copulation and fertility. Testosterone (T) induces sexual differentiation of this SNB Neuromuscular System during development and maintains its activation in adulthood. In the rat, T-induced effects mostly involve the androgen receptor (AR). However, the role of central AR in T-induced effects remains to be studied with pertinent genetic models. We addressed this question by using specific motoneuron immunolabeling and retrograde tracing in mice selectively disrupted for AR in the nervous System. This work reveals that nervous System AR is not required either for T-induced development of BC-LA muscles and perinatal sparing of SNB motoneurons from atrophy or for adult sensitivity of BC-LA muscles to T. By contrast, loss of AR expression in the nervous System resulted in SNB motoneurons having smaller somata and shorter dendrites than controls. We studied the ...
Max Mulder - One of the best experts on this subject based on the ideXlab platform.
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Neuromuscular-System-Based Tuning of a Haptic Shared Control Interface for UAV Teleoperation
IEEE Transactions on Human-Machine Systems, 2017Co-Authors: Jan Smisek, David Abbink, Emmanuel Sunil, Marinus M. Van Paassen, Max MulderAbstract:Haptic guidance is a promising way to support unmanned aerial vehicle (UAV) operators, but the design of haptic guidance forces is often heuristic. This paper describes the design and experimental validation of a Systematic Neuromuscular analysis-based tuning procedure for haptic guidance, here applied to haptic collision avoidance System for UAV teleoperation. This tuning procedure is hypothesized to reduce operator workload as compared with current heuristic tuning methods. The proposed procedure takes into consideration the estimated mechanical response of the Neuromuscular System (NMS) to haptic cues. A “relax-task” setting of the NMS, for which reflexive and muscular activation is minimal, is chosen as the design point for tuning the haptic support, as this setting is expected to yield minimal physical workload. The paper first presents a Neuromuscular identification experiment, performed to estimate the “relax task” admittance of an operator's arm. The averaged admittance of a group of subjects (n=10) was then used for tuning the haptic shared controller, which was subsequently evaluated in its ability to support different operators (n=12) in a simulated unmanned aerial vehicle surveillance task. Results show that our novel tuning procedure indeed reduces operator workload and also improves situation awareness compared with haptic settings that ignore the NMS. In fact, it is shown that overtuning, which frequently occurs for these heuristically tuned Systems, leads to even lower user acceptance scores than interfaces without any haptic support.
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Design of Test Signals for Identification of Neuromuscular Admittance
IFAC-PapersOnLine, 2016Co-Authors: Anand K. Bhoelai, David Abbink, M.m. Van Paassen, Max MulderAbstract:The human Neuromuscular System can be seen as a versatile and extremely adaptive actuator. Through co-contraction and reex modulation, the properties of the Neuromuscular System can be modified, leading to a change in movement response to externally applied forces. These properties are normally expressed in the form of the Neuromuscular admittance. In a series of standard tasks, the force-, relax-, and position-task admittance of the Neuromuscular System can be identified. However, the test signals used in these tasks can also limit the range of reex adaptation possible and wrong choice can create a phenomenon analogous to cross-over regression in manual control tasks, and force the human to use only a limited range of the possible reex adaptation. This paper presents a Systematic investigation, through a model study, of the inuence of test signals on the range of reex adaptation. For this, criteria for test signal acceptability have been developed. The method is applied to the currently used test signals consisting of a high and a low shelf, and enables the selection of the high shelf bandwidth.
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SMC - Validation of a tuning method for haptic shared control using Neuromuscular System analysis
2014 IEEE International Conference on Systems Man and Cybernetics (SMC), 2014Co-Authors: Emmanuel Sunil, Jan Smisek, Marinus M. Van Paassen, Max MulderAbstract:This research investigates a Neuromuscular analysis based tuning procedure for haptic shared control Systems that has been hypothesized to improve subjective operator workload when compared to heuristic tuning methods. Here, the tuning procedure takes into consideration the response of the Neuromuscular System to haptic cues. Human arm stiffness, the Neuromuscular property of concern, can be changed by modulating reflex strength. The ‘relax task’ setting of the Neuromuscular System, for which reflexes are minimized, is chosen as the design point for tuning haptic cues as it is hypothesized to lead to the lowest workload. A simulated haptic collision avoidance System for unmanned aircraft teleoperation is used as a platform to experimentally validate the tuning method. The results show that the novel tuning procedure, particularly for relax task tuning, substantially improves workload and situational awareness over conditions that ignores the Neuromuscular System. Additionally, over-tuning, which frequently occurs for heuristic methods, leads to worse user acceptance than a condition without haptic support.
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Validation of a tuning method for haptic shared control using Neuromuscular System analysis
2014 IEEE International Conference on Systems Man and Cybernetics (SMC), 2014Co-Authors: Emmanuel Sunil, Jan Smisek, Marinus M. Van Paassen, Max MulderAbstract:This research investigates a Neuromuscular analysis based tuning procedure for haptic shared control Systems that has been hypothesized to improve subjective operator workload when compared to heuristic tuning methods. Here, the tuning procedure takes into consideration the response of the Neuromuscular System to haptic cues. Human arm stiffness, the Neuromuscular property of concern, can be changed by modulating reflex strength. The `relax task' setting of the Neuromuscular System, for which reflexes are minimized, is chosen as the design point for tuning haptic cues as it is hypothesized to lead to the lowest workload. A simulated haptic collision avoidance System for unmanned aircraft teleoperation is used as a platform to experimentally validate the tuning method. The results show that the novel tuning procedure, particularly for relax task tuning, substantially improves workload and situational awareness over conditions that ignores the Neuromuscular System. Additionally, over-tuning, which frequently occurs for heuristic methods, leads to worse user acceptance than a condition without haptic support.
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Identification of time variant Neuromuscular admittance using wavelets
2011 IEEE International Conference on Systems Man and Cybernetics, 2011Co-Authors: Mark Mulder, David Abbink, Marinus M. Van Paassen, Tom Verspecht, David Balderas C. S., Alfred Schouten, Erwin De Vlugt, Max MulderAbstract:Driver control behaviour is highly time variant. When studying the Neuromuscular System of drivers in interaction with the steering wheel, the common Fourier System identification techniques are only applicable when time-invariant behaviour is assumed. This paper describes how wavelets can be used to identify time-variant Neuromuscular admittance. Using the Morlet wavelet transformation, time domain signals are transformed to a time-frequency representation. A non-parametric, time-variant frequency response function can be estimated using the transformed signals. A model of the Neuromuscular System of a driver controlling a steering wheel was used to generate time-variant data. This paper shows that the Morlet wavelet transformation is a valid tool for estimating accurate time-variant frequency responses of Neuromuscular arm dynamics. The results of this article give us confidence that wavelet analysis can be used on experimental data, with lower signal-to-noise ratio, too. This will allow us to identify how drivers adjust their Neuromuscular System during driving.
Kalina Raskin - One of the best experts on this subject based on the ideXlab platform.
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characterization of the spinal nucleus of the bulbocavernosus Neuromuscular System in male mice lacking androgen receptor in the nervous System
Endocrinology, 2012Co-Authors: Kalina Raskin, Clarisse Marieluce, M C Picot, Veronique Bernard, Philippe MaillyAbstract:Motoneurons in the spinal nucleus of the bulbocavernosus (SNB) and their target bulbocavernosus (BC) and levator ani (LA) muscles play a role in male copulation and fertility. Testosterone (T) induces sexual differentiation of this SNB Neuromuscular System during development and maintains its activation in adulthood. In the rat, T-induced effects mostly involve the androgen receptor (AR). However, the role of central AR in T-induced effects remains to be studied with pertinent genetic models. We addressed this question by using specific motoneuron immunolabeling and retrograde tracing in mice selectively disrupted for AR in the nervous System. This work reveals that nervous System AR is not required either for T-induced development of BC-LA muscles and perinatal sparing of SNB motoneurons from atrophy or for adult sensitivity of BC-LA muscles to T. By contrast, loss of AR expression in the nervous System resulted in SNB motoneurons having smaller somata and shorter dendrites than controls. We studied the ...
Dale R Sengelaub - One of the best experts on this subject based on the ideXlab platform.
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Trophic Effects of Brain-Derived Neurotrophic Factor Blockade in an Androgen-Sensitive Neuromuscular System
Endocrinology, 2010Co-Authors: Tom Verhovshek, Dale R SengelaubAbstract:In adult male rats, androgens are necessary for the maintenance of the motoneurons and their target muscles of the sexually dimorphic, steroid-sensitive spinal nucleus of the bulbocavernosus (SNB) Neuromuscular System, regulating motoneuron and muscle morphology, function, and expression of trophic factors. Castration of males results in somal, dendritic, and muscle atrophy as well as increases in brain-derived neurotrophic factor (BDNF) in the target musculature. Because BDNF can have either facilitative or inhibitory effects in other Systems, we examined SNB Neuromuscular morphology after BDNF blockade using a fusion protein (tyrosine kinase receptor type B IgG). Blockade of BDNF in gonadally intact males resulted in hypertrophy of SNB motoneuron dendrites and target musculature, suggesting that normal levels of BDNF are inhibitory in SNB Neuromuscular System. BDNF blockade in castrated males prevented SNB motoneuron atrophy and attenuated target muscle weight loss. This is the first demonstration that the highly androgen-sensitive SNB motoneuron dendrites and target muscles can be maintained in the absence of gonadal hormones and, furthermore, that blocking BDNF can have trophic effects on skeletal muscle. These results suggest that whereas BDNF is involved in the signaling cascade mediating the androgenic support of SNB Neuromuscular morphology, its action can be inhibitory. Furthermore, the elevations in BDNF after castration may be responsible for the castration-induced atrophy in SNB motoneurons and target muscles, and the trophic effects of androgens may be mediated in part through a suppression of BDNF. These results may have relevance to therapeutic approaches to the treatment of neurodegenerative disease or myopathies.
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testosterone metabolites differentially maintain adult morphology in a sexually dimorphic Neuromuscular System
Developmental Neurobiology, 2010Co-Authors: Tom Verhovshek, Katherine E Buckley, Melissa A Sergent, Dale R SengelaubAbstract:The lumbar spinal cord of rats contains the sexually dimorphic, steroid-sensitive spinal nucleus of the bulbocavernosus (SNB). Androgens are necessary for the development of the SNB Neuromuscular System, and in adulthood, continue to influence the morphology and function of the motoneurons and their target musculature. However, estrogens are also involved in the development of the SNB System, and are capable of maintaining function in adulthood. In this experiment we assessed the ability of testosterone metabolites, estrogens and non-aromatizable androgens, to maintain Neuromuscular morphology in adulthood. Motoneuron and muscle morphology was assessed in adult normal males, sham-castrated males, castrated males treated with testosterone, dihydrotestosterone, estradiol, or left untreated, and gonadally intact males treated with the 5α-reductase inhibitor finasteride or the aromatase inhibitor fadrozole. After 6 weeks of treatment, SNB motoneurons were retrogradely labeled with cholera toxin-HRP and reconstructed in three dimensions. Castration resulted in reductions in SNB target muscle size, soma size, and dendritic morphology. Testosterone treatment after castration maintained SNB soma size, dendritic morphology, and elevated target muscle size; dihydrotestosterone treatment also maintained SNB dendritic length, but was less effective than testosterone in maintaining both SNB soma size and target muscle weight. Treatment of intact males with finasteride or fadrozole did not alter the morphology of SNB motoneurons or their target muscles. In contrast, estradiol treatment was completely ineffective in preventing castration-induced atrophy of the SNB Neuromuscular System. Together, these results suggest that the maintenance of adult motoneuron or muscle morphology is strictly mediated by androgens.
D Gorbunov - One of the best experts on this subject based on the ideXlab platform.
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chaotic dynamics of Neuromuscular System parameters and the problems of the evolution of complexity
Biophysics, 2017Co-Authors: Valeriy Eskov, O Filatova, T V Gavrilenko, D GorbunovAbstract:The evolution rate v(t) varies among diverse bioSystems, but a general theory can be formulated when the dynamics of the bioSystem stater x = x(t) = (x1, x2, x m ) T is considered in the m-dimensional space of states. A mathematical approach is proposed for evaluating such processes and describes the processes in terms of particular chaos of the statistical distribution functions f(x). In the case of complex multicomponent Systems with a high dimension number m (m ≫1) of the phase space of states, we propose using pairwise comparison matrices of samples x(t) when homeostasis is constant and calculating the parameters of quasiattractors. The Glensdorff–Prigogine thermodynamic approach to estimating evolution is inefficient in assessing the third-type Systems, while it is applicable and the Prigogine theorem works at the level of molecular Systems. Alterations in the state of the human Neuromuscular System were found to lead to chaotic changes in the statistical functions f(x) in tremor recording samples, while quasiattractor parameters demonstrate a certain regularity.
