scholarly journals Rhythmic auditory stimuli modulates movement recovery to perturbation during locomotion

2021 ◽  
pp. jeb.237073
Author(s):  
Deepak K. Ravi ◽  
Marc Bartholet ◽  
Andreas Skiadopoulos ◽  
Jenny A. Kent ◽  
Jordan Wickstrom ◽  
...  
Keyword(s):  
Recovery Time ◽  
Complex Dynamics ◽  
Center Of Mass ◽  
Intrinsic Property ◽  
Auditory Stimuli ◽  
Bipedal Locomotion ◽  
Comprehensive Understanding ◽  
Locomotor System ◽  
Novel Method ◽  
Analytical Tools

The capacity to recover after a perturbation is a well-known intrinsic property of physiological systems, including the locomotor system, and can be termed resilience. Despite an abundance of metrics proposed to measure the complex dynamics of bipedal locomotion, analytical tools for quantifying resilience are lacking. Here, we introduce a novel method to directly quantify resilience to perturbations during locomotion. We examine the extent to which synchronizing stepping with two different temporal structured auditory stimuli (periodic and 1/f structure) during walking modulates resilience to a large unexpected perturbation. Recovery time after perturbation was calculated from the horizontal velocity of body's center of mass. Our results indicate that synchronizing stepping with 1/f stimulus elicited greater resilience to mechanical perturbations during walking compared to the periodic stimulus (3.3 seconds faster). Our proposed method may help to gain a comprehensive understanding of movement recovery behavior of humans and other animals in their ecological contexts.

Analysis and Identification of Off-Odor Compounds in Electronic Systems

2006 ◽  
Author(s):  
Mary Ann Nailos ◽  
Dan Stein ◽  
Lawrence T. Nielsen ◽  
Anna Iwasinska
Keyword(s):  
Volatile Compounds ◽  
Electronic Systems ◽  
Detection Thresholds ◽  
Detection And Identification ◽  
Odor Compounds ◽  
Novel Method ◽  
Odor Analysis ◽  
Analytical System ◽  
Task Perception ◽  
Analytical Tools

Abstract The detection and identification of substances that give rise to aromas and off-odors is often a difficult task. Perception of odors is very subjective and odor detection thresholds vary from person to person. The identification of trace levels of compounds responsible for perceived odors is difficult using conventional analytical tools. This paper will focus on a novel method for sampling and analyzing aromatic volatile compounds using an analytical system specifically designed for odor analysis.

The Gait of Children With and Without Cerebral Palsy: Work, Energy, and Angular Momentum

2011 ◽  
Vol 27 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Shawn Russell ◽  
Bradford Bennett ◽  
Pradip Sheth ◽  
Mark Abel
Keyword(s):  
Cerebral Palsy ◽  
Angular Momentum ◽  
Walking Speed ◽  
Center Of Mass ◽  
Whole Body ◽  
Mass Motion ◽  
Bipedal Locomotion ◽  
Kinematic Data ◽  
Internal Work ◽  
Body Energy

This paper describes a method to characterize gait pathologies like cerebral palsy using work, energy, and angular momentum. For a group of 24 children, 16 with spastic diplegic cerebral palsy and 8 typically developed, kinematic data were collected at the subjects self selected comfortable walking speed. From the kinematics, the work—internal, external, and whole body; energy—rotational and relative linear; and the angular momentum were calculated. Our findings suggest that internal work represents 53% and 40% respectively of the whole body work in gait for typically developed children and children with cerebral palsy. Analysis of the angular momentum of the whole body, and other subgroupings of body segments, revealed a relationship between increased angular momentum and increased internal work. This relationship allows one to use angular momentum to assist in determining the kinetics and kinematics of gait which contribute to increased internal work. Thus offering insight to interventions which can be applied to increase the efficiency of bipedal locomotion, by reducing internal work which has no direct contribution to center of mass motion, in both normal and pathologic populations.

scholarly journals Novel methodology for assessing total recovery time in response to unexpected perturbations while walking

2019 ◽  
Author(s):  
Uri Rosenblum ◽  
Lotem Kribus-Shmiel ◽  
Gabi Zeilig ◽  
Yotam Bahat ◽  
Shani Kimel-Naor ◽  
...  
Keyword(s):  
Recovery Time ◽  
Center Of Mass ◽  
Principal Component ◽  
Random Order ◽  
Step Length ◽  
Step Width ◽  
Total Recovery ◽  
Age Related ◽  
Different Types ◽  
Anterior Posterior

AbstractWalking stability is achieved by adjusting the medio-lateral and anterior-posterior dimensions of the base of support (step length and step width, respectively) to contain an extrapolated center of mass. We aimed to calculate total recovery time after different types of perturbations during walking, and use it to compare young and older adults following different types of perturbations. Walking trials were performed in 12 young (age 26.92 ± 3.40 years) and 12 older (age 66.83 ± 1.60 years) adults. Perturbations were introduced at different phases of the gait cycle, on both legs and in anterior-posterior or medio-lateral directions, in random order. A novel algorithm was developed to determine total recovery time values for regaining stable step length and step width parameters following the different perturbations and compared between the two participant groups under low and high cognitive load conditions, using principal component analysis (PCA). We analyzed 829 perturbations each for step length and step width. The algorithm successfully estimated total recovery time in 91.07% of the runs. PCA and statistical comparisons showed significant differences in step length and step width recovery times between anterior-posterior and medio-lateral perturbations, but no age-related differences. Initial analyses demonstrated the feasibility of comparisons based on total recovery time calculated using our algorithm.

scholarly journals Probabilistic tools to gauge 6-month infants' ability to detect contingency

2019 ◽  
Author(s):  
Alice Dauphin ◽  
J. Kevin O'Regan
Keyword(s):  
Motor Skills ◽  
Body Movement ◽  
Auditory Stimuli ◽  
Fine Motor ◽  
Control Group ◽  
Individual Level ◽  
Group I ◽  
Level I ◽  
The Individual ◽  
Analytical Tools

Adults are capable of very fine motor skills whereas newborn babies’ motions are less accurately adjusted to the environment. It has been suggested that babies are sensitive to sensorimotor contingencies so they can acquire their body knowhow by gradually linking each body movement to its perceptual consequences. The research we pursued in the team is part of this theoretical framework. We use behavioural measurements to study how babies refine their body knowhow over time.During my internship, we studied arm differentiation in infants of age 6 months. An artificial contingency was established between the movements of one of the babies’ arms and the appearance of visual and auditory stimuli on both of their arms. My goal was to develop analytical tools to assess if babies detect the contingency (i.e. if they realize that they caused the occurrence of the stimuli). I tried to reproduce the probabilistic methodology developed by J. Watson in his experiments with 4month old babies. I could not obtain reliable results and so pursued my investigations. I adapted Watson’s analytical tools to create a binary indicator measuring the success of babies at the individual level. I showed that babies can differentiate between a situation where without doubt they have no control and a situation where they could be the cause of the stimulus. However, because babies who tried to test the contingency behaved similarly in both the test and the control group I can not ascertain that babies from the contingent group understood that they triggered the contingency.

scholarly journals Adapting Footfall Rhythmicity to Auditory Perturbations Affects Resilience of Locomotor Behavior: A Proof-of-Concept Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Deepak K. Ravi ◽  
Caroline C. Heimhofer ◽  
William R. Taylor ◽  
Navrag B. Singh
Keyword(s):  
Steady State ◽  
Fall Risk ◽  
Recovery Time ◽  
Center Of Mass ◽  
Locomotor Behavior ◽  
Proof Of Concept ◽  
Limited Information ◽  
Novel Approach ◽  
Temporal Adaptation ◽  
The Mean

For humans, the ability to effectively adapt footfall rhythm to perturbations is critical for stable locomotion. However, only limited information exists regarding how dynamic stability changes when individuals modify their footfall rhythm. In this study, we recorded 3D kinematic activity from 20 participants (13 males, 18–30 years old) during walking on a treadmill while synchronizing with an auditory metronome sequence individualized to their baseline walking characteristics. The sequence then included unexpected temporal perturbations in the beat intervals with the subjects required to adapt their footfall rhythm accordingly. Building on a novel approach to quantify resilience of locomotor behavior, this study found that, in response to auditory perturbation, the mean center of mass (COM) recovery time across all participants who showed deviation from steady state (N = 15) was 7.4 (8.9) s. Importantly, recovery of footfall synchronization with the metronome beats after perturbation was achieved prior (+3.4 [95.0% CI +0.1, +9.5] s) to the recovery of COM kinematics. These results highlight the scale of temporal adaptation to perturbations and provide implications for understanding regulation of rhythm and balance. Thus, our study extends the sensorimotor synchronization paradigm to include analysis of COM recovery time toward improving our understanding of an individual’s resilience to perturbations and potentially also their fall risk.

scholarly journals Quantitative and temporal measurement of dynamic autophagy rates

2021 ◽  
Author(s):  
Nitin Sai Beesabathuni ◽  
Priya S. Shah
Keyword(s):  
Steady State ◽  
Temporal Resolution ◽  
Recovery Time ◽  
Cellular Response ◽  
High Sensitivity ◽  
Limited Information ◽  
Comprehensive Understanding ◽  
Autophagy Flux ◽  
New Approach ◽  
Temporal Measurement

AbstractAutophagy is a multistep degradative process that is essential for maintaining cellular homeostasis. Systematically quantifying flux through this pathway is critical for gaining fundamental insights and effectively modulating this process that is dysregulated during many diseases. Established methods to quantify flux use steady state measurements, which provide limited information about the perturbation and the cellular response. We present a theoretical and experimental framework to measure autophagic steps in the form of rates under non-steady state conditions. We use this approach to measure temporal responses to rapamycin and wortmannin treatments, two commonly used autophagy modulators. We quantified changes in autophagy rates in as little as 10 minutes, which can establish direct mechanisms for autophagy perturbation before feedback begins. We identified concentration-dependent effects of rapamycin on the initial and temporal progression of autophagy rates. We also found variable recovery time from wortmannin’s inhibition of autophagy, which is further accelerated by rapamycin. In summary, this new approach enables the quantification of autophagy flux with high sensitivity and temporal resolution and facilitates a comprehensive understanding of this process.

Spatial structure of multiwhisker receptive fields in the barrel cortex is stimulus dependent

2011 ◽  
Vol 106 (2) ◽  
pp. 986-998 ◽  
Author(s):  
Julie Le Cam ◽  
Luc Estebanez ◽  
Vincent Jacob ◽  
Daniel E. Shulz
Keyword(s):  
Spatial Structure ◽  
Barrel Cortex ◽  
Center Of Mass ◽  
Receptive Fields ◽  
Intrinsic Property ◽  
Spatial Separation ◽  
Cortical Layer ◽  
Trigeminal System ◽  
Response Latencies ◽  
Receptive Field Organization

The tactile sensations mediated by the whisker-trigeminal system allow rodents to efficiently detect and discriminate objects. These capabilities rely strongly on the temporal and spatial structure of whisker deflections. Subthreshold but also spiking receptive fields in the barrel cortex encompass a large number of vibrissae, and it seems likely that the functional properties of these multiwhisker receptive fields reflect the multiple-whisker interactions encountered by the animal during exploration of its environment. The aim of this study was to examine the dependence of the spatial structure of cortical receptive fields on stimulus parameters. Using a newly developed 24-whisker stimulation matrix, we applied a forward correlation analysis of spiking activity to randomized whisker deflections (sparse noise) to characterize the receptive fields that result from caudal and rostral directions of whisker deflection. We observed that the functionally determined principal whisker, the whisker eliciting the strongest response with the shortest latency, differed according to the direction of whisker deflection. Thus, for a given neuron, maximal responses to opposite directions of whisker deflections could be spatially separated. This spatial separation resulted in a displacement of the center of mass between the rostral and caudal subfields and was accompanied by differences between response latencies in rostral and caudal directions of whisker deflection. Such direction-dependent receptive field organization was observed in every cortical layer. We conclude that the spatial structure of receptive fields in the barrel cortex is not an intrinsic property of the neuron but depends on the properties of sensory input.

scholarly journals Robust Analysis and Laser Stripe Center Extraction for Rail Images

2021 ◽  
Vol 11 (5) ◽  
pp. 2038
Author(s):  
Huiping Gao ◽  
Guili Xu
Keyword(s):  
Center Of Mass ◽  
Adaptive Threshold ◽  
Experimental Results ◽  
Threshold Segmentation ◽  
Robust Analysis ◽  
Brightness Enhancement ◽  
Laser Stripe ◽  
Speed Up ◽  
Novel Method

In this paper, a novel method for the effective extraction of the light stripes in rail images is proposed. First, a preprocessing procedure that includes self-adaptive threshold segmentation and brightness enhancement is adopted to improve the quality of the rail image. Secondly, center of mass is utilized to detect the center point of each row of the image. Then, to speed up the procedure of centerline optimization, the detected center-points are segmented into several parts based on the geometry of the rail profile. Finally, piecewise fitting is adopted to obtain a smooth and robust centerline. The performance of this method is analyzed in detail, and experimental results show that the proposed method works well for rail images.

Parametrically excited inverted double pendulum and efficient bipedal walking with an upper body

Robotica ◽  
2013 ◽  
Vol 31 (6) ◽  
pp. 875-886 ◽  
Author(s):  
Toyoyuki Honjo ◽  
Akinori Nagano ◽  
Zhi-Wei Luo
Keyword(s):  
Center Of Mass ◽  
Bipedal Walking ◽  
Upper Body ◽  
Bipedal Locomotion ◽  
Double Pendulum ◽  
Lower Body ◽  
Parametrically Excited ◽  
Body Dynamics ◽  
Walking Locomotion ◽  
Complex Movement

SUMMARYWalking locomotion involves complex movement of total center of mass. Not only the lower body behavior but also the upper body behavior affects the walking characteristics. Therefore, in this paper we derive the principle of parametrically excited inverted double pendulum to consider both lower body and upper body dynamics. We propose one approach to utilize the upper body behavior of the robot for energy efficient bipedal locomotion. In addition, we analyze the property of parametrically excited inverted double pendulum.

A Novel Method to Model the Dynamics of an Uniball Robot

2014 ◽  
Author(s):  
Pramod Chembrammel ◽  
Thenkurussi Kesavadas
Keyword(s):  
Fixed Point ◽  
Equations Of Motion ◽  
Center Of Mass ◽  
Euler Method ◽  
Kinematics And Dynamics ◽  
Euler Angles ◽  
Geometrical Center ◽  
Principal Moments Of Inertia ◽  
Geometrical Features ◽  
Novel Method

In this paper the kinematics and dynamics of a uniball robot is demonstrated. The motion of a uniball robot is derived from the dynamics of a sphere rolling on a surface which is considered as a motion about a fixed point. The equations of motion are derived using Newton-Euler method incorporating the geometrical features of the surface. A uniball-robot can be considered as a Routh’s sphere whose center of mass is not at the geometrical center and have equal principal moments of inertia in the plane perpendicular to the axis connecting the center of mass and the geometrical center. The Euler angles are obtained using the Meusnier’s theorem which deals with the evolution of the surface as the robot moves along.

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