Search Results
Results 551 - 600 of 1469
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Tsibidis George D - - 2007
The nematode Caenorhabditis elegans responds to an impressive range of chemical, mechanical and thermal stimuli and is extensively used to investigate the molecular mechanisms that mediate chemosensation, mechanotransduction and thermosensation. The main behavioral output of these responses is manifested as alterations in animal locomotion. Monitoring and examination of such alterations ...
Schtickzelle Nicolas - - 2007
Dispersal between habitat patches is a key process in the functioning of (meta)populations. As distance between suitable habitats increases, the ongoing process of habitat fragmentation is expected to generate strong selection pressures on movement behaviour. This leads to an increase or decrease of dispersal according to its cost relative to ...
Sosnik Ronen R Weizmann Institute of Science, Rehovot 71600, Israel. - - 2007
We recently showed that extensive training on a sequence of planar hand trajectories passing through several targets resulted in the co-articulation of movement components and in the formation of new movement elements (primitives) (Sosnik et al. in Exp Brain Res 156(4):422-438, 2004). Reduction in movement duration was accompanied by the ...
Clark Damon A - - 2007
When navigating spatial thermal gradients, the nematode C. elegans migrates toward colder temperatures until it reaches its previous cultivation temperature, exhibiting cryophilic movement. The strategy for effecting cryophilic movement is the biased random walk: C. elegans extends (shortens) periods of forward movement that are directed down (up) spatial thermal gradients ...
Huber Jessica E - - 2006
Examination of movement parameters and consistency has been used to infer underlying neural control of movement. However, there has been no systematic investigation of whether the way individuals are asked (or cued) to increase loudness alters articulation. This study examined whether different cues to elicit louder speech induce different lip ...
Baguma-Nibasheka M - - 2006
As developmental biologists we study the role of fetal movements in providing continuity between prenatal and postnatal life. There are two major categories of fetal motility. The first category consists of movements that have an obvious effect on the survival or development of the fetus (e.g., changes of position, sucking ...
Thompson Shelby G - - 2007
The current experiment suggests that the speed/accuracy tradeoff is composed of two classes of constraints, effector and task. We examined the effects of movement distance, target size, orientation of the movement in the workspace, and C-D gain on the kinematics of discrete pointing movements made with computer mouse. It was ...
Bahill A Terry - - 2007
The right-hand rules show the direction of the spin-induced deflection of baseball pitches: thus, they explain the movement of the fastball, curveball, slider and screwball. The direction of deflection is described by a pair of right-hand rules commonly used in science and engineering. Our new model for the magnitude of ...
Gutenkunst Ryan - - 2007
We use observed movement tracks of Atlantic bluefin tuna in the Gulf of Maine and mathematical modeling of this movement to identify possible resource patches. We infer bounds on the overall sizes and distribution of such patches, even though they are difficult to quantify by direct observation in situ. To ...
Dounskaia Natalia - - 2007
It has been observed that the motion of the arm end-point (the hand, fingertip or the tip of a pen) is characterized by a number of regularities (kinematic invariants). Trajectory is usually straight, and the velocity profile has a bell shape during point-to-point movements. During drawing movements, a two-thirds power ...
Bernier Pierre-Michel - - 2006
This study sought to determine whether intact proprioception is required to adapt to a novel kinematic environment. We compared adaptation with a rotated visual feedback between a deafferented patient and healthy participants. They performed reaching movements towards visible targets while vision of the cursor was rotated by 30 degrees with ...
Bourdin C - - 2006
In everyday life, because of unexpected mechanical perturbation applied to the hand or to the whole body, hand movements may become suddenly inaccurate. With prolonged exposure to the perturbation, trajectories slowly recover their normal accuracy, which is the mark of motor adaptation. However, full development of this adaptive process in ...
Carey James R - - 2006
The authors used functional magnetic resonance imaging to explore whether the primary motor area (M1) serves a processing role in a finger-movement tracking task, emphasizing attention to accuracy, beyond its execution role of simple movements, with no attention to accuracy. Twenty healthy subjects performed alternating conditions: Rest, involving no finger ...
Rapp David N - - 2006
Traditional research on situation models has examined the accessibility of locations and objects during narrative experiences. These studies have described a ubiquitous gradient effect: Spatial locations and objects in reader focus are more accessible than locations farther from this focus, with accessibility decreasing as a function of distance. How might ...
Jonas M M Department of Neurology, University Medical Center Hamburg Eppendorf, Martinistr. 52, 20246, Hamburg, Germany. - - 2007
Behavioural advantages for imitation of human movements over movements instructed by other visual stimuli are attributed to an 'action observation-execution matching' (AOEM) mechanism. Here, we demonstrate that priming/exogenous cueing with a videotaped finger movement stimulus (S1) produces specific congruency effects in reaction times (RTs) of imitative responses to a target ...
Sato Hiroki - - 2006
We have developed a wavelet-based method of detecting body-movement artifacts in optical topography (OT) signals. Although OT, which is a noninvasive imaging technique for measuring hemodynamic response related to brain activation, is particularly useful for studying infants, the signals occasionally contain undesirable artifacts caused by body movements, so data corrupted ...
Hwang Ing-Shiou - - 2006
In light of the interplay between limb oscillatory outputs and the outcome performance of movement effectors, this study was undertaken to investigate neuromotor control in the upper limb during position tracking and posture holding. Sixteen volunteers conducted a postural pointing task and two index tracking maneuvers at 0.3 and 0.6 ...
Spencer Rebecca M C - - 2006
Constraints underlying bimanual coordination have traditionally been explained by dynamic interactions between the effectors. However, the present experiments demonstrate that a fundamental constraint on bimanual performance is the manner in which task goals are represented. In Experiment 1, participants vocalized during in-phase and anti-phase bimanual movements. As expected, most participants ...
Puca Rosa Maria - - 2006
The present research is based on the assumption that people differ in their responsiveness to incentives and threats. In two experiments we examined whether the trait corresponding to the responsiveness to threats (avoidance motive) and the trait corresponding to the responsiveness to incentives (approach motive) influence voluntary motor behavior toward ...
Hirai Hiroaki - - 2006
This paper describes the hierarchical architecture for a rhythmic coordination between robots, which suits juggling-like tasks involving sensory-motor coordination. The authors' approach, which is interpreted as a "bidirectional weak coupling" to the environment, does not require either the environmental model or continuously monitoring the environment but can adapt the robots ...
Torres Elizabeth - - 2006
Is the movement duration time known before we move? To answer this question, a new experimental paradigm is introduced that for the first time monitors the acquisition of a new motor skill in rhesus monkeys. Straight reaches were interleaved with reaches around physical obstacles that elicited a different path geometry. ...
Foisy Martin M Neurological Science Research Center, Department of Physiology, Rehabilitation Institute of Montreal, University of Montreal and Center for Interdisciplinary Research Studies in Rehabilitation CRIR, 6300 Darlington Ave, Montreal, QC, - - 2006
We addressed the fundamental questions of which variables underlie the control of arm movement and how they are stored in motor memory, reproduced and modified in the process of adaptation to changing load conditions. Such variables are defined differently in two major theories of motor control (internal models and threshold ...
Heuer Herbert - - 2006
Temporal and spatial movement characteristics are often seen as controlled separately, although they are not independent. Even in the case of simple oscillations mean frequency and mean amplitude covary when one or the other is changed intentionally. The present experiment revealed that in rapid finger oscillations there is also a ...
Bortoletto Marta - - 2006
The present study investigated the role of pre-motion positivity in movement initiation and the reason why it is not reliably detectable in every study participant. Nineteen right-handed participants performed self-initiated simple movements of the right index finger and mouth while electroencephalography activity was recorded. Most of the participants showed a ...
Pinkston Jonathan W - - 2006
Recent research has demonstrated that avian species may show an enhanced locomotor response to repeated drug exposure, a phenomenon called sensitization. Further research in this domain is warranted as such results not only establish the generality of previous findings, but may lend to a better understanding of sensitization in general. ...
Begon M - - 2007
Determination of the hip joint centre (HJC) using a functional approach requires access to the kinematics of various body postures. The present study aimed to determine the combined impact of the nature of the movement, its type and the number of cycles, on the accuracy of HJC estimation. Kinematics noise ...
O'Leary John G - - 2006
Local field potentials (LFPs) recorded from primary motor cortex (MI) have been shown to be tuned to the direction of visually guided reaching movements, but MI LFPs have not been shown to be tuned to the direction of an upcoming movement during the delay period that precedes movement in an ...
Wallace Douglas G - - 2006
Rat exploration is an organized series of trips. Each exploratory trip involves an outward tour from the refuge followed by a return to the refuge. A tour consists of a sequence of progressions with variable direction and speed concatenated by stops, whereas the return consists of a single direct progression. ...
Wallace Douglas G - - 2006
Rat exploration is an organized series of trips. Each exploratory trip involves an outward tour from the refuge followed by a return to the refuge. A tour consists of a sequence of progressions with variable direction and speed concatenated by stops, whereas the return consists of a single direct progression. ...
Sylvestre Pierre A - - 2006
Simple activities like picking up the morning newspaper or catching a ball require finely coordinated movements of multiple body segments. How our brain readily achieves such kinematically complex yet remarkably precise multijoint movements remains a fundamental and unresolved question in neuroscience. Many prevailing theoretical frameworks ensure multijoint coordination by means ...
Chen Jessie J Department of Physiology and Neuroscience, New York University School of Medicine, 550 First Avenue, MSB 442, New York, NY 10016, USA. - - 2006
Accuracy of shifting movements between two notes was examined in nine cellists (intermediate-professional skill levels). Three pairs of notes separated by different distances were tested under the same movement rate. Finger position on the string was measured by a circuit. Angular velocities of the left upper arm and forearm were ...
Daprati Elena - - 2007
We tested the hypothesis that our ability to detect fine kinematics variations is tuned to reveal more subtle differences when the motion pattern belongs to the observer compared to another individual. To this purpose, we analyzed the responses of 15 subjects in a same-different task on pairs of movements, which ...
Teixeira Luis Augusto - - 2006
Movement reprogramming in a task requiring timing accuracy was investigated in young and elderly individuals. The task consisted of manually hitting a hemiball in synchrony with the arrival of a moving light stimulus running through an electronic trackway. Movement reprogramming was required by unexpectedly changing the regular stimulus velocity at ...
Mazyn Liesbeth I N - - 2006
In the present study, the limits of human catching behavior were challenged to investigate quantitative and qualitative adaptations of the catching movement when performing under varying ball speeds, implying minor as well as severe temporal constraints. Nine male participants caught balls approaching at speeds ranging from 8.5 to 19.7 m/s ...
Demiris Yiannis - - 2006
Recent computational approaches to action imitation have advocated the use of hierarchical representations in the perception and imitation of demonstrated actions. Hierarchical representations present several advantages, with the main one being their ability to process information at multiple levels of detail. However, the nature of the hierarchies in these approaches ...
Runge M - - 2006
Neuromuscular parameters that describe locomotion are indispensable variables for the diagnosis and treatment of frailty, fall risk and osteoporosis. A scientifically-based standardized locomotor assessment should be an essential part of medical examinations in research and clinical practice. There has been no previous consensus regarding which test procedures should be included ...
Pitsillides Andrew A - - 2006
It has long been appreciated that studying the embryonic chick in ovo provides a variety of advantages, including the potential to control the embryo's environment and its movement independently of maternal influences. This allowed early workers to identify movement as a pivotal factor in the development of the locomotor apparatus. ...
Lyons James J Department of Kinesiology, McMaster University, Hamilton, ON, Canada. - - 2006
Recent studies have shown that the initial impulse associated with goal-directed aiming movements typically brings the limb to a position short of the target. This is because target overshooting is associated with greater temporal and energy costs than target undershooting. Presumably these costs can be expected to vary not only ...
Rand Miya K MK Motor Control Laboratory, Department of Kinesiology, Arizona State University, Box 870404, Tempe, AZ 85287-0404, USA. - - 2006
This study investigates coordination between hand transport and grasp movement components by examining a hypothesis that the hand location, relative to the object, in which aperture closure is initiated remains relatively constant under a wide range of transport speed. Subjects made reach-to-grasp movements to a dowel under four speed conditions: ...
Vernazza-Martin S S Laboratoire Sport et Culture EA2931, Université Paris-X Nanterre, 200 av. de la République, 92001 Nanterre, France. - - 2006
The aim of this investigation was to study the adaptation to an unstable support surface of kinematic synergy responsible for equilibrium control during upper trunk movements. Eight adult subjects were asked to bend their upper trunk forward to an angle of 35 degrees and then to hold the final position ...
Cruz E G EG Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Suite 1406, 345 E. Superior Street, Chicago, IL 60611, - - 2006
The goal of this study was to examine the characteristics of planar fingertip movements with respect to the hand. Ten subjects with no known neuromuscular impairments performed a series of point-to-point movements with their dominant index fingertips. Subjects were instructed to move between five pairs of targets within the workspace ...
Bailey Helen - - 2006
1. Broad-scale telemetry studies have greatly improved our understanding of the ranging patterns and habitat-use of many large vertebrates. However, there often remains considerable uncertainty over the function of different areas or the factors influencing habitat selection. Further insights into these processes can be obtained through analyses of finer scale ...
Miyakawa T - - 2006
The purpose of the present study was to determine the appropriate reference facial expression and to examine the reproducibility of our system using two commercially available video cameras in consideration of functional diagnosis of perioral muscles. The following items were investigated: 1) influence of forward and backward movements and the ...
Motiei-Langroudi Rouzbeh - - 2006
Temporal information is an embedded feature of our sensory and motor experiences. How is temporal information encoded in the brain? In the two-stage theory of timing, an explicit representation of timing is responsible for the movement initiation while movement duration is coded implicitly. We investigated the correlation of movement duration ...
Heuer Herbert - - 2006
In almost all studies of bimanual movements with same and different amplitudes, the difference between amplitudes has been confounded with a difference between endpoint locations. The present authors varied those parameters orthogonally. In addition, they presented target locations on the surface on which the movements were produced (direct cues) and ...
Levit-Binnun Nava N Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, POB 26, Rehovot, 76100, - - 2006
In an earlier study, Viviani and Stucchi (J Exp Psychol Hum Percept Perform 18:603-623, 1992) have introduced a visual illusion, whereby it was shown that when subjects are asked to determine what movement of a light spot, when tracing an elliptical trajectory, appears to be most uniform, they tend to ...
Zacks Jeffrey M - - 2006
People perceive ongoing activity in terms of discrete temporal events. Distinctive changes in the movement of objects or actors may contribute to the perception that one event has ended and another has begun. However, little is known about the quantitative contribution of movement information to the processing of events. This ...
Ridderikhoff Arne - - 2006
This study examined if and how phase entrainment by movement-related afference-- induced by passive movements of the contralateral hand-- contributes to the coordinative stability of rhythmic bimanual movements. The results revealed that phase-shifted passive movements of the dominant or the nondominant hand induced similar entrainment effects on the active movements ...
Ma Yingliang - - 2006
We present the methods that were used in capturing a library of human movements for use in computer-animated displays of human movement. The library is an attempt to systematically tap into and represent the wide range of personal properties, such as identity, gender, and emotion, that are available in a ...
Pozzo Thierry - - 2006
How do we extrapolate the final position of hand trajectory that suddenly vanishes behind a wall? Studies showing maintenance of cortical activity after objects in motion disappear suggest that internal model of action may be recalled to reconstruct the missing part of the trajectory. Although supported by neurophysiological and brain ...
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