A new view on visuomotor channels: The case of the disappearing dynamics

Neilson, Peter D.; Neilson, Megan D.

doi:10.1016/j.humov.2004.08.007

Cited by 6 publications

(3 citation statements)

References 43 publications

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“…A simple two‐dimensional model was developed by Neilson32 to predict the barrier performance of polymer composites containing platelet particles strictly on the basis of tortuosity arguments, and it was further developed with consideration of the dependence of the tortuosity factor on the orientational order of the sheets in a continuous manner. It can be argued that the distribution of graphite nanosheets in the xNBR matrix is uniform according to the study of the nanocomposite morphology, and if we assume that the orientation of the nanosheets is in a random mode, the following equation can be used to model the dependence of the relative gas permeability ( P / P 0 , where P is the gas permeability and P 0 is the initial gas permeability) on the filler volume fraction (ϕ) and the aspect ratio (2 r / d , where r is the radius of the nanosheets and d is the thickness):33 …”

Section: Resultsmentioning

confidence: 99%

Mechanical and functional properties of composites based on graphite and carboxylated acrylonitrile butadiene rubber

Yang

Zhang

Shi

et al. 2010

J of Applied Polymer Sci

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In this study, carboxylated acrylonitrile butadiene rubber (xNBR)/expanded graphite (EG) nanocomposites were prepared with a latex compounding technique by ultrasonic stirring. The dispersion of EG in the xNBR matrix was investigated with transmission electron microscopy, scanning electron microscopy, and X-ray diffraction analysis. EG could be exfoliated into lots of nanosheets dispersing in the xNBR matrix. More EG loading resulted in the presence of a few incompletely exfoliated agglomerates. The mechanical properties (hardness, tensile modulus, and tensile strength) of the xNBR/EG composites were determined.Dynamic mechanical thermal analysis was also performed, and it showed that the nanosheets of EG somewhat immobilized the motion of rubber macromolecular chains and led to the shifting and broadening of the tan d peak toward higher temperatures. Many other functional properties of EG-filled xNBR composites were studied, and it was established that the composites had excellent electrical conductivity as well as gas-barrier and wear properties.

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Section: Resultsmentioning

confidence: 99%

Mechanical and functional properties of composites based on graphite and carboxylated acrylonitrile butadiene rubber

Yang

Zhang

Shi

et al. 2010

J of Applied Polymer Sci

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“…Human movements would appear uncoordinated and purposeless if the DOF varied independently (Neilson & Neilson, 2004). Indeed, most movements are typified by spatiotemporal patterns that are repeatable and stereotypical, suggesting that the seemingly unsolvable DOF problem is somehow resolved as if the DOF were eliminated, a phenomenon pointed out by Bernstein (Bernstein, 1967).…”

Section: Functional Degrees Of Freedom (Fdof)mentioning

confidence: 99%

Functional Degrees of Freedom

Li¹

2006

Motor Control

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Mechanical degrees of freedom (DOF) are defined as the minimum number of independent coordinates needed to describe a system's position. The human musculoskeletal system has many mechanical DOF through which countless movements are accomplished. In the motor control field, one of the aspirations is to understand how the many DOF are organized for movement execution-the so-called DOF problem. Natural movements are characterized by the coordination of the DOF such that few vary independently. The concept of functional degrees of freedom (fDOF) is introduced to describe the very limited DOF of purposeful, coordinated movements. Deterministic (i.e., constraint satisfaction) and statistical (i.e., principal component analysis) approaches are used to determine fDOF. In contrast to DOF as a mechanical descriptor, fDOF emphasizes the mechanisms of human movements and corroborates our search for the solution to the DOF problem.

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“…These methodological divisions result in study designs that support models that are biased towards the modality under consideration, i.e. motor, visual, or cognitive variables, which do not encourage effective testing of holistic theoretical models that attempt to provide a more integrated perspective (Caiani & Ferretti, 2017;Neilson & Neilson, 2004;Schenk, 2010). Indeed, the central question "how is sensory information transformed into purposeful acts?"…”

Section: Introductionmentioning

confidence: 99%

Concurrent Multimodal Data Acquisition During Brain Scanning is within Reach

Molina

Lamp

Hugrass

et al. 2021

Preprint

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Background: Previous brain-scanning research exploring the neural mechanisms underpinning visuomotor planning and control has mostly been done without simultaneous motion-tracking and eye-tracking. Employing concurrent methodologies would enhance understanding of the brain mechanisms underlying visuomotor integration of cognitive, visual, ocular, and motor aspects of reaching and grasping behaviours. Therefore, this work presents the methods and validation for a high-speed, multimodal and synchronized system to holistically examine neural processes that are involved in visually-guided movement. Methods: The multimodal methods included high speed 3D motion tracking (Qualisys), 2D eye-tracking (SR Research), and magnetoencephalography (MEG; Elekta) that were synchronized to millisecond precision. Previous MRIs were taken to provide improved spatial localization. The methods section describes the system layout and acquisition parameters to achieve multimodal synchronization. Pilot results presented here are preliminary data from a larger study including 29 participants. Using a pincer grip, five people (3 male, 2 female, ages 30-32) reached for and grasped a translucent dowel 50 times, after it was pseudorandomly illuminated. The object illumination was the Go cue. Seven discrete time points (events) throughout the task were chosen for investigation of simultaneous brain, hand and eye activity associated with specific visual (Go cue), oculomotor (1st saccade after Go), motor (Reaction Time; RT, Maximum Velocity: MV, Maximum Grip Width; MGW) or cognitive (Ready, End) mechanisms. Time-frequency analyses were performed on the MEG data sourced from the left precentral gyrus to explore task-related changes time-locked to these chosen events. Pilot results: Basic kinematic parameters including RT, MV, MGW, Movement Time, and Total Time were similar to previous, seminal research by Castiello, Paulignan and Jeannerod, (1991), using a similar task. Although no gaze instructions were given, eye-tracking results indicated volunteers mostly gazed at or near the target object when Ready (72%), and then hardly looked away throughout the rest of the task at the important events sampled here (92% - 98%). At the End event, when lifting the dowel, on average, participants gazed at or near the target object 100% of the time. Although saccades > 100 ms after Go, but prior to RT were made on average in about one fourth (M = 13, SD = 6) of trials, a mixed model (REML) indicated their latency in timing after the Go was significantly (F = 13.376, p = .001) associated with RT scores on those trials (AIC = 724, R m2 = 0.407, Rc2= 0.420). Neural activity relative to baseline in the beta band was desynchronized for the visually guided reach periods, beginning prior to Go, and remaining sustained until beyond End, after the grasp and lift were executed. Conclusion: This study presents the layout, acquisition parameters and validation for a multimodal, synchronized system designed to record data from the hand, eye and brain simultaneously, with millisecond precision during an ecologically-valid prehension task with physical, 3D objects. The pilot results align with previous research made with single or bimodal data recordings. This multimodal method enables full-brain modelling that can holistically map the precise location and timing of neural activity involved in the visual, oculomotor, motor and cognitive aspects of reach-to-grasp planning and control.

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A new view on visuomotor channels: The case of the disappearing dynamics

Cited by 6 publications

References 43 publications

Mechanical and functional properties of composites based on graphite and carboxylated acrylonitrile butadiene rubber

Mechanical and functional properties of composites based on graphite and carboxylated acrylonitrile butadiene rubber

Functional Degrees of Freedom

Concurrent Multimodal Data Acquisition During Brain Scanning is within Reach

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