Evaluation of Activation Mechanism of Ankle Muscles During Upright Stance Push-recovery

2020 ◽  
Author(s):  
Yaqian Zhou ◽  
Muye Pang ◽  
Xiangui Xu ◽  
Biwei Tang ◽  
Kui Xiang
Keyword(s):  
Activation Mechanism ◽  
Upright Stance ◽  
Push Recovery ◽  
Ankle Muscles

scholarly journals Long-lasting event-related beta synchronizations of electroencephalographic activity in response to support-surface perturbations during upright stance

2020 ◽  
Author(s):  
Akihiro Nakamura ◽  
Yasuyuki Suzuki ◽  
Matija Milosevic ◽  
Taishin Nomura
Keyword(s):  
Upper Extremities ◽  
Support Surface ◽  
Intermittent Control ◽  
Upright Posture ◽  
Upright Stance ◽  
Beta Band ◽  
Ankle Muscles ◽  
Related Potentials ◽  
High Beta ◽  
Postural Recovery

AbstractMovement related beta band cortical oscillations, including beta rebound after execution and/or suppression of movement, have drawn attention in upper extremity motor control literature. However, fewer study focused on beta band oscillations during postural control in upright stance. Here, we examined beta rebound and other components of electroencephalogram (EEG) activity during perturbed upright stance to investigate supraspinal contributions to postural stabilization. Particularly, we aimed to clarify the timing and duration of beta rebound within a non-sustained, but long-lasting, postural recovery process that occurs more slowly compared to upper extremities. To this end, EEG signals were acquired from nine healthy young adults in response to a support-surface perturbation, together with the center of pressure (CoP) and mass (CoM) and electromyogram (EMG) activities of ankle muscles. Event-related potentials (ERPs) and event-related spectral perturbations were computed from EEG data using the perturbation-onset as a triggering event. After short-latency (< 0.3 s) ERPs, our results showed high-beta band power decrease (event-related desynchronization), which was followed by an event-related synchronization at high-beta band and theta band desynchronization. Specifically, beta synchronization (beta rebound) was sustained for as long as three seconds. EMGs of the ankle muscles and the ankle and hip joint torques remained activated in the first half period of the beta rebound. They returned to the steady-state in the remaining phase, where the CoP/CoM were in their final approach to the equilibrium. We propose possible mechanistic causes of the long-lasting beta rebound, which may be related to underlying intermittent control strategy in upright stance.New & NoteworthyBeta rebound cortical activity was identified during postural recovery from a perturbed upright stance. Contrary to upper extremities, it was initiated before the recovery of motion was completed, and sustained for as long as three seconds. Those novel characteristics of the beta rebound might be caused by slow dynamics of the upright posture and by selections of on/off switching in an intermittent feedback controller, which was shown to stabilize upright posture.

A Classification of Postural Sway Patterns During Upright Stance in Healthy Adults and Patients with Parkinson’s Disease

2011 ◽  
Vol 15 (8) ◽  
pp. 997-1010 ◽  
Author(s):  
Tomohisa Yamamoto ◽  
◽  
Yasuyuki Suzuki ◽  
Kunihiko Nomura ◽  
Taishin Nomura ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Postural Sway ◽  
Postural Instability ◽  
Elderly Subjects ◽  
Intermittent Control ◽  
Upright Stance ◽  
Muscle Torque ◽  
Ankle Muscles ◽  
Ankle Muscle

The intermittent control during human quiet upright stance is a new hypothesis which claims that the active neural feedback control generating the ankle muscle torque is switched off and on intermittently at appropriate timings. The intermittent strategy is capable of providing compliant posture while ensuring robust stability. Contrastingly, impairment of postural reflexes in patients with Parkinson’s disease (PD) causes postural instability. Here we hypothesize that the instability in PD patients might be due to a loss of appropriate intermittent activations in the feedback muscle torque during stance. In order to provide evidence for this hypothesis, we characterized stochastic postural sway patterns measured as changes in center of pressure (CoP) and activities of ankle muscles during quiet stance in healthy young and elderly subjects as well as PD patients. To this end, sway patterns and associated ankle muscle activities were quantified by several indices including the CoP sway area, scaling factors of double-power-law power spectra of the sway, as well as levels and patterns of the muscle activations. Hierarchical cluster analysis was performed to suggest that the sway patterns could be classified into two major types. The first type consisted mainly of sway and muscle activation patterns from healthy subjects and some PD patients with the mild level of severity, and they showed features indicating the intermittent control. The second type, consisting mainly of PD patients with relatively severe levels of motor symptoms, was accompanied with non-intermittent but tonic muscle activities and sway areas either smaller or larger than those in the first type. Moreover, the major two types were further classified into several subtypes with distinguishable characteristics. Results suggested that a loss of the intermittent activations in the ankle muscles could be a cause of the postural instability for a population of PD patients.

Inhibition of NGLY1 inactivates the transcription factor Nrf1 and potentiates proteasome inhibitor cytotoxicity

2017 ◽  
Author(s):  
Carolyn Bertozzi ◽  
Fred Tomlin ◽  
Ulla Gerling-Driessen ◽  
Yi-Chang Liu ◽  
Ryan Flynn ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Small Molecule ◽  
Proteasome Inhibitor ◽  
Activation Mechanism ◽  
Cancer Drugs ◽  
Small Molecule Library ◽  
Library Screen ◽  
In Cells

We discovered that the proteostasis modulating transcription factor Nrf1 requires cytosolic de-N-glycosylation by the N-glycanase NGly1 as part of its activation mechanism. Through a covalent small molecule library screen, we discovered an inhibitor of NGly1 that blocks Nrf1 activation in cells and potentiates the activity of proteasome inhibitor cancer drugs. The requirement of NGly1 for Nrf1 activity likely underlies several pathologies associated with a rare hereditary deficiency in NGly1.

STRUCTURAL COMPONENTS OF THE PRIVATE MEDICAL SECTOR ACTIVATION MECHANISM

Economical ◽  
2019 ◽  
Vol 2 (2(21)) ◽  
pp. 170-177
Author(s):  
Anzhela Bairak ◽  
Keyword(s):  
Health Care ◽  
Health Care System ◽  
Activation Mechanism ◽  
Practical Significance ◽  
Structural Components ◽  
Medical Sector ◽  
Analysis And Synthesis ◽  
Private Medicine ◽  
Care System

The article examines the problems of private medicine in the health care system of the country. The aim of the article is to determine the structural components of the mechanism of activation of the private medical sector as a reserve for the provision of quality and affordable medical services and a driver for the development of the medical industry. The descriptive-analytical method, methods of analysis and synthesis, comparison, statistical, analysis and scientific generalization were used in the paper. The study substantiates the strengthening of the role of the private medical sector in the health care management system. The key problems of the domestic private medical sector and the restraining factors of its development are identified. It is concluded that it is necessary to develop a mechanism to promote the development of private medicine through a policy of active change in the health care system. The directions of activation of the private medical sector as a target reference point in the process of determining the structural elements of the organizational and economic mechanism are outlined. The structural detail of the mechanism of activation of the private medical sector for optimization of the health care system is offered. The practical significance of the obtained results is that the results of the research presented in the article are a practical basis for the development and improvement of mechanisms of public administration in the field of health care.

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