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https://www.readbyqxmd.com/read/28076435/walking-ahead-the-headed-social-force-model
#1
Francesco Farina, Daniele Fontanelli, Andrea Garulli, Antonio Giannitrapani, Domenico Prattichizzo
Human motion models are finding an increasing number of novel applications in many different fields, such as building design, computer graphics and robot motion planning. The Social Force Model is one of the most popular alternatives to describe the motion of pedestrians. By resorting to a physical analogy, individuals are assimilated to point-wise particles subject to social forces which drive their dynamics. Such a model implicitly assumes that humans move isotropically. On the contrary, empirical evidence shows that people do have a preferred direction of motion, walking forward most of the time...
2017: PloS One
https://www.readbyqxmd.com/read/28072803/neural-correlates-of-maladaptive-pain-behavior-in-chronic-neck-pain-a-single-case-control-fmri-study
#2
Konstantin Beinert, Audrey Mouthon, Martin Keller, Michael Mouthon, Jean-Marie Annoni, Wolfgang Taube
Chronic neck pain patients display functional impairments like decreased range of motion, decreased strength, and reduced sensorimotor function. In patients without structural damage, the reason for the persistence of pain is not well understood. Therefore, it is assumed that in chronic pain states, memory processes play an important role. We have now detected and tested a patient that might help us to better understand the neural correlates of maladaptive pain expectation/memory. This patient displays chronic neck pain and restricted unilateral motion of the cervical spine to the left...
January 2017: Pain Physician
https://www.readbyqxmd.com/read/28048642/su-f-t-364-monte-carlo-dose-verification-of-volumetric-modulated-arc-therapy-plans-using-aapm-tg-119-test-patterns
#3
R Onizuka, F Araki, T Ohno, Y Nakaguchi
PURPOSE: To investigate the Monte Carlo (MC)-based dose verification for VMAT plans by a treatment planning system (TPS). METHODS: The AAPM TG-119 test structure set was used for VMAT plans by the Pinnacle3 (convolution/superposition), using a Synergy radiation head of a 6 MV beam with the Agility MLC. The Synergy was simulated with the EGSnrc/BEAMnrc code, and VMAT dose distributions were calculated with the EGSnrc/DOSXYZnrc code by the same irradiation conditions as TPS...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046908/su-g-jep1-12-head-to-head-performance-characterization-of-two-multileaf-collimator-tracking-algorithms-for-radiotherapy
#4
V Caillet, R O'Brien, E Colvill, P Poulsen, D Moore, J Booth, A Sawant, P Keall
PURPOSE: Multi-leaf collimator (MLC) tracking is being clinically pioneered to continuously compensate for thoracic and abdominal motion during radiotherapy. The purpose of this work is to characterize the performance of two MLC tracking algorithms for cancer radiotherapy, based on a direct optimization and a piecewise leaf fitting approach respectively. METHODS: To test the algorithms, both physical and in silico experiments were performed. Previously published high and low modulation VMAT plans for lung and prostate cancer cases were used along with eight patient-measured organ-specific trajectories...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28032370/modular-level-alterations-of-structure-function-coupling-in-schizophrenia-connectome
#5
Yu Sun, Zhongxiang Dai, Junhua Li, Simon L Collinson, Kang Sim
Convergent evidences have revealed that schizophrenia is associated with brain dysconnectivity, which leads to abnormal network organization. However, discrepancies were apparent between the structural connectivity (SC) and functional connectivity (FC) studies, and the relationship between structural and functional deficits in schizophrenia remains largely unknown. In this study, resting-state functional magnetic resonance imaging and structural diffusion tensor imaging were performed in 20 patients with schizophrenia and 20 matched healthy volunteers (patients/controls = 19/17 after head motion rejection)...
December 29, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27978830/angiopoietin-2-signaling-plays-a-critical-role-in-neural-crest-cell-migration
#6
Mary Cathleen McKinney, Rebecca McLennan, Paul M Kulesa
BACKGROUND: Collective neural crest cell migration is critical to the form and function of the vertebrate face and neck, distributing bone, cartilage, and nerve cells into peripheral targets that are intimately linked with head vasculature. The vasculature and neural crest structures are ultimately linked, but when and how these patterns develop in the early embryo are not well understood. RESULTS: Using in vivo imaging and sophisticated cell behavior analyses, we show that quail cranial neural crest and endothelial cells share common migratory paths, sort out in a dynamic multistep process, and display multiple types of motion...
December 15, 2016: BMC Biology
https://www.readbyqxmd.com/read/27919100/viewpoint-oscillation-improves-the-perception-of-distance-travelled-based-on-optic-flow
#7
Martin Bossard, Cédric Goulon, Daniel R Mestre
When static observers are presented with a visual simulation of forward self-motion, they generally misestimate distance travelled relative to a previously seen distant target: It has been suggested that this finding can be accounted for by a "leaky path integration" model. In the present study, using a similar experimental procedure, this result was confirmed. It was also established that combining the translational optical flow with simulated head oscillations (similar to those during natural walking) improved the subjects' perception of the distance travelled in comparison with a purely translational flow...
December 1, 2016: Journal of Vision
https://www.readbyqxmd.com/read/27915367/the-virtual-reality-head-mounted-display-oculus-rift-induces-motion-sickness-and-is-sexist-in-its-effects
#8
Justin Munafo, Meg Diedrick, Thomas A Stoffregen
Anecdotal reports suggest that motion sickness may occur among users of contemporary, consumer-oriented head-mounted display systems and that women may be at greater risk. We evaluated the nauseogenic properties of one such system, the Oculus Rift. The head-mounted unit included motion sensors that were sensitive to users' head movements, such that head movements could be used as control inputs to the device. In two experiments, seated participants played one of two virtual reality games for up to 15 min. In Experiment 1, 22% of participants reported motion sickness, and the difference in incidence between men and women was not significant...
December 3, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/27895619/a-functional-magnetic-resonance-imaging-study-of-head-movements-in-cervical-dystonia
#9
Cecília N Prudente, Randall Stilla, Shivangi Singh, Cathrin Buetefisch, Marian Evatt, Stewart A Factor, Alan Freeman, Xiaoping Philip Hu, Ellen J Hess, K Sathian, H A Jinnah
Cervical dystonia (CD) is a neurological disorder characterized by abnormal movements and postures of the head. The brain regions responsible for these abnormal movements are not well understood, because most imaging techniques for assessing regional brain activity cannot be used when the head is moving. Recently, we mapped brain activation in healthy individuals using functional magnetic resonance imaging during isometric head rotation, when muscle contractions occur without actual head movements. In the current study, we used the same methods to explore the neural substrates for head movements in subjects with CD who had predominantly rotational abnormalities (torticollis)...
2016: Frontiers in Neurology
https://www.readbyqxmd.com/read/27871096/responses-and-injuries-to-pmhs-in-side-facing-and-oblique-seats-in-horizontal-longitudinal-sled-tests-per-faa-emergency-landing-conditions
#10
John R Humm, Narayan Yoganandan, Frank A Pintar, Richard L DeWeese, David M Moorcroft, Amanda M Taylor, Brian Peterson
The objective of the present exploratory study is to understand occupant responses in oblique and side-facing seats in the aviation environment, which are increasingly installed in modern aircrafts. Sled tests were conducted using intact Post Mortem Human Surrogates (PMHS) seated in custom seats approximating standard aircraft geometry. End conditions were selected to represent candidate aviation seat and restraint configurations. Three-dimensional head center-of-gravity linear accelerations, head angular velocities, and linear accelerations of the T1, T6, and T12 spinous processes, and sacrum were obtained...
November 2016: Stapp Car Crash Journal
https://www.readbyqxmd.com/read/27869148/motor-noise-is-rich-signal-in-autism-research-and-pharmacological-treatments
#11
E B Torres, K Denisova
The human body is in constant motion, from every breath that we take, to every visibly purposeful action that we perform. Remaining completely still on command is a major achievement as involuntary fluctuations in our motions are difficult to keep under control. Here we examine the noise-to-signal ratio of micro-movements present in time-series of head motions extracted from resting-state functional magnetic resonance imaging scans in 1048 participants. These included individuals with autism spectrum disorders (ASD) and healthy-controls in shared data from the Autism Brain Imaging Data Exchange (ABIDE) and the Attention-Deficit Hyperactivity Disorder (ADHD-200) databases...
November 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27814855/older-adult-alexander-technique-practitioners-walk-differently-than-healthy-age-matched-controls
#12
Kate A Hamel, Christopher Ross, Brooke Schultz, Matthew O'Neill, David I Anderson
The Alexander Technique (AT) seeks to eliminate harmful patterns of tension that interfere with the control of posture and movement and in doing so, it may serve as a viable intervention method for increasing gait efficacy in older adults. The purpose of this study was to compare the comfortable pace gait kinematics of older AT practitioners with those of healthy, age-matched controls. Participants were six licensed AT practitioners and seven healthy age-matched controls between the ages of 61-76. During the stance phase, AT participants exhibited significantly greater ankle stance range of motion (ROM) and plantar flexion at toe off, as well as lower ROM of the trunk and head compared to controls...
October 2016: Journal of Bodywork and Movement Therapies
https://www.readbyqxmd.com/read/27811303/developmental-changes-in-head-movement-kinematics-during-swimming-in-xenopus-laevis-tadpoles
#13
Sara Hänzi, Hans Straka
During the post-embryonic developmental growth of animals, a number of physiological parameters such as locomotor performance, dynamics and behavioural repertoire are adjusted to match the requirements determined by changes in body size, proportions and shape. Moreover, changes in movement parameters also cause changes in the dynamics of self-generated sensory stimuli, to which motion-detecting sensory systems have to adapt. Here, we examined head movements and swimming kinematics of Xenopus laevis tadpoles with a body length of 10-45 mm (developmental stage 46-54) and compared these parameters with fictive swimming, recorded as ventral root activity in semi-intact in vitro preparations...
January 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/27781442/synchronization-of-multi-agent-systems-with-metric-topological-interactions
#14
Lin Wang, Guanrong Chen
A hybrid multi-agent systems model integrating the advantages of both metric interaction and topological interaction rules, called the metric-topological model, is developed. This model describes planar motions of mobile agents, where each agent can interact with all the agents within a circle of a constant radius, and can furthermore interact with some distant agents to reach a pre-assigned number of neighbors, if needed. Some sufficient conditions imposed only on system parameters and agent initial states are presented, which ensure achieving synchronization of the whole group of agents...
September 2016: Chaos
https://www.readbyqxmd.com/read/27751941/sources-and-implications-of-whole-brain-fmri-signals-in-humans
#15
Jonathan D Power, Mark Plitt, Timothy O Laumann, Alex Martin
Whole-brain fMRI signals are a subject of intense interest: variance in the global fMRI signal (the spatial mean of all signals in the brain) indexes subject arousal, and psychiatric conditions such as schizophrenia and autism have been characterized by differences in the global fMRI signal. Further, vigorous debates exist on whether global signals ought to be removed from fMRI data. However, surprisingly little research has focused on the empirical properties of whole-brain fMRI signals. Here we map the spatial and temporal properties of the global signal, individually, in 1000+ fMRI scans...
October 14, 2016: NeuroImage
https://www.readbyqxmd.com/read/27705769/myosin-induced-gliding-patterns-at-varied-mgatp-unveil-a-dynamic-actin-filament
#16
Elina Bengtsson, Malin Persson, Mohammad A Rahman, Saroj Kumar, Hideyo Takatsuki, Alf Månsson
Actin filaments have key roles in cell motility but are generally claimed to be passive interaction partners in actin-myosin-based motion generation. Here, we present evidence against this static view based on an altered myosin-induced actin filament gliding pattern in an in vitro motility assay at varied [MgATP]. The statistics that characterize the degree of meandering of the actin filament paths suggest that for [MgATP] ≥ 0.25 mM, the flexural rigidity of heavy meromyosin (HMM)-propelled actin filaments is similar (without phalloidin) or slightly lower (with phalloidin) than that of HMM-free filaments observed in solution without surface tethering...
October 4, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27629710/distinct-fmri-responses-to-self-induced-versus-stimulus-motion-during-free-viewing-in-the-macaque
#17
Brian E Russ, Takaaki Kaneko, Kadharbatcha S Saleem, Rebecca A Berman, David A Leopold
UNLABELLED: Visual motion responses in the brain are shaped by two distinct sources: the physical movement of objects in the environment and motion resulting from one's own actions. The latter source, termed visual reafference, stems from movements of the head and body, and in primates from the frequent saccadic eye movements that mark natural vision. To study the relative contribution of reafferent and stimulus motion during natural vision, we measured fMRI activity in the brains of two macaques as they freely viewed >50 hours of naturalistic video footage depicting dynamic social interactions...
September 14, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27591489/adaptations-to-walking-on-an-uneven-terrain-for-individuals-with-and-without-developmental-coordination-disorder
#18
J Gentle, A L Barnett, K Wilmut
Given the importance of walking in everyday life, understanding why this is challenging for some populations is particularly important. Studies focusing on gait patterns of individuals with Developmental Coordination Disorder (DCD) have shown that whilst increased variability is characteristic of walking patterns for this group, differences in spatio-temporal gait variables seem only to arise when task demands increase. However, these differences occur under rather artificial conditions, for example using a treadmill...
October 2016: Human Movement Science
https://www.readbyqxmd.com/read/27586485/human-field-of-regard-field-of-view-and-attention-bias
#19
Woncheol Jang, Joon-Ho Shin, Mingyu Kim, Kwanguk Kenny Kim
BACKGROUND AND OBJECTIVE: Human field of regard (FOR) is an important concept that should be considered along with field of view (FOV) for people with/without handicaps, but previous studies have neglected this aspect of human perception. In the current study, we suggest and test a new virtual reality (VR) software with which to evaluate individual's detection abilities in the human FOR. METHODS: We conducted measurements of human FOV, FOR, and FOR with visual cue (FOR-cue), and we evaluated healthy adults' responses in a first experiment...
October 2016: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/27581452/galvanic-vestibular-stimulation-cellular-substrates-and-response-patterns-of-neurons-in-the-vestibulo-ocular-network
#20
Kathrin D Gensberger, Anna-Kristin Kaufmann, Haike Dietrich, Francisco Branoner, Roberto Banchi, Boris P Chagnaud, Hans Straka
UNLABELLED: Galvanic vestibular stimulation (GVS) uses modulated currents to evoke neuronal activity in vestibular endorgans in the absence of head motion. GVS is typically used for a characterization of vestibular pathologies; for studies on the vestibular influence of gaze, posture, and locomotion; and for deciphering the sensory-motor transformation underlying these behaviors. At variance with the widespread use of this method, basic aspects such as the activated cellular substrate at the sensory periphery or the comparability to motion-induced neuronal activity patterns are still disputed...
August 31, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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