Articles de revues : « Time and movement »

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Orban de Xivry, Jean-Jacques, Valéry Legrain et Philippe Lefèvre. « Overlap of movement planning and movement execution reduces reaction time ». Journal of Neurophysiology 117, n^o 1 (1 janvier 2017) : 117–22. http://dx.doi.org/10.1152/jn.00728.2016.

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Motor planning is the process of preparing the appropriate motor commands in order to achieve a goal. This process has largely been thought to occur before movement onset and traditionally has been associated with reaction time. However, in a virtual line bisection task we observed an overlap between movement planning and execution. In this task performed with a robotic manipulandum, we observed that participants ( n = 30) made straight movements when the line was in front of them (near target) but often made curved movements when the same target was moved sideways (far target, which had the same orientation) in such a way that they crossed the line perpendicular to its orientation. Unexpectedly, movements to the far targets had shorter reaction times than movements to the near targets (mean difference: 32 ms, SE: 5 ms, max: 104 ms). In addition, the curvature of the movement modulated reaction time. A larger increase in movement curvature from the near to the far target was associated with a larger reduction in reaction time. These highly curved movements started with a transport phase during which accuracy demands were not taken into account. We conclude that an accuracy demand imposes a reaction time penalty if processed before movement onset. This penalty is reduced if the start of the movement consists of a transport phase and if the movement plan can be refined with respect to accuracy demands later in the movement, hence demonstrating an overlap between movement planning and execution. NEW & NOTEWORTHY In the planning of a movement, the brain has the opportunity to delay the incorporation of accuracy requirements of the motor plan in order to reduce the reaction time by up to 100 ms (average: 32 ms). Such shortening of reaction time is observed here when the first phase of the movement consists of a transport phase. This forces us to reconsider the hypothesis that motor plans are fully defined before movement onset.

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Nauert, Elliot, et Douglas J. Gillan. « Individual Measures of Time Perception Predict Performance in a Timed Reaching Task ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 61, n^o 1 (septembre 2017) : 1380–84. http://dx.doi.org/10.1177/1541931213601829.

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In temporally-constrained reaching tasks, participants make rapid movements to a target while making their movements last a designated length of time. It has been well-established that effective target width, a measure of spatial accuracy, increases linearly with movement speed. This study sought to understand how individual differences in temporal sensitivity affect this speed-accuracy tradeoff. It was found that time sensitivity did not affect spatial components of the timed reaching task, but it was related to temporal components of the task. Ideas regarding the role of time perception in movement planning as well as differences in movement strategies for short and long target intervals are discussed.

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Whitley, Jim D., et Lou Montano. « Relation between Reaction Time and Movement Time in College Wrestlers ». Perceptual and Motor Skills 74, n^o 1 (février 1992) : 171–76. http://dx.doi.org/10.2466/pms.1992.74.1.171.

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Interrelationships among reaction time, movement time, and win-loss percentage were studied for 16 college wrestlers who executed a standard wrestling double-leg attack .62 m in length. There was a significant correlation of .64 between reaction time and movement time, which differed from the typical pattern of nonsignificant and significant but small correlations previously reported in reaction time-movement time studies of both athletes and nonathletes. This departure from the magnitude of correlation commonly reported between these variables (explained by Henry's theory of neuromotor specificity) was thought to be related to the fact that reaction time and movement time in wrestling movements are taught as a single, common response. Another finding of interest was a significant correlation (−.62) between movement time and win-loss record. This finding indicates that in this small group of wrestlers movement time played a more important role in their success than reaction time.

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Dias de Andrade, André. « Time and movement ». Metodo 11, n^o 2 (2024) : 91–120. http://dx.doi.org/10.19079/metodo.11.2.91.

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Andres, Robert O., et Kenny J. Hartung. « Prediction of Head Movement Time Using Fitts’ Law ». Human Factors : The Journal of the Human Factors and Ergonomics Society 31, n^o 6 (décembre 1989) : 703–13. http://dx.doi.org/10.1177/001872088903100606.

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Fitts’ movement time prediction equation has been applied and manipulated in analyzing movements of the upper and lower extremities in healthy populations. One common job modification for physically challenged workers is the use of a head or chin stick to depress keys on a keyboard, making use of head movements when movements of the extremities are problematic. The purpose of this research was to assess the applicability of Fitts’ law for the prediction of head movement time. Movement was restricted in healthy subjects by limiting body movement below the neck. Subjects were asked to reciprocally move a chin stylus between targets of various widths and separations. The present study found that Fitts’ law was a robust predictor of head movement time in healthy, college-age males using a chin stylus. Although small within-subjects trends were noted, there were no significant learning effects from Session 1 to Session 2. The mean information-processing rate for the experimental head movement was 7 bits/s, much less than that reported for extremities. These results can provide rehabilitation and industrial engineers valuable insight into the added demands of jobs designed to use repetitive head movements.

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Sommer, Martin, Joseph Classen, Leonardo G. Cohen et Mark Hallett. « Time Course of Determination of Movement Direction in the Reaction Time Task in Humans ». Journal of Neurophysiology 86, n^o 3 (1 septembre 2001) : 1195–201. http://dx.doi.org/10.1152/jn.2001.86.3.1195.

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The primary motor cortex produces motor commands that include encoding the direction of movement. Excitability of the motor cortex in the reaction time (RT) task can be assessed using transcranial magnetic stimulation (TMS). To elucidate the timing of the increase in cortical excitability and of the determination of movement direction before movement onset, we asked six right-handed, healthy subjects to either abduct or extend their right thumb after a go-signal indicated the appropriate direction. Between the go-signal and movement onset, single TMS pulses were delivered to the contralateral motor cortex. We recorded the direction of the TMS-induced thumb movement and the amplitude of motor-evoked potentials (MEPs) from the abductor pollicis brevis and extensor pollicis brevis muscles. Facilitation of MEPs from the prime mover, as early as 200 ms before the end of the reaction time, preceded facilitation of MEPs from the nonprime mover, and both preceded measurable directional change. Compared with a control condition in which no voluntary movement was required, the direction of the TMS-induced thumb movement started to change in the direction of the intended movement as early as 90 ms before the end of the RT, and maximum changes were seen shortly before the end of reaction time. Movement acceleration also increased with maxima shortly before the end of the RT. We conclude that in concentric movements a change of the movement direction encoded in the primary motor cortex occurs in the 200 ms prior to movement onset, which is as early as increased excitability itself can be detected.

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Newell, K. M., Les G. Carlton et Seonjin Kim. « Time and Space-Time Movement Accuracy ». Human Performance 7, n^o 1 (mars 1994) : 1–21. http://dx.doi.org/10.1207/s15327043hup0701_1.

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Noh, Minseong, Heungju Ahn et Sang C. Lee. « Real-Time Human Movement Recognition Using Ultra-Wideband Sensors ». Electronics 13, n^o 7 (30 mars 2024) : 1300. http://dx.doi.org/10.3390/electronics13071300.

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This study introduces a methodology for the real-time detection of human movement based on two legs using ultra-wideband (UWB) sensors. Movements were primarily categorized into four states: stopped, walking, lingering, and the transition between sitting and standing. To classify these movements, UWB sensors were used to measure the distance between the designated point and a specific point on the two legs in the human body. By analyzing the measured distance values, a movement state classification model was constructed. In comparison to conventional vision/laser/LiDAR-based research, this approach requires fewer computational resources and provides distinguished real-time human movement detection within a CPU environment. Consequently, this research presents a novel strategy to effectively recognize human movements during human–robot interactions. The proposed model effectively discerned four distinct movement states with classification accuracy of around 95%, demonstrating the novel strategy’s efficacy.

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Sternad, Dagmar, et Karl M. Newell. « Modeling movement variability in space and time ». Behavioral and Brain Sciences 20, n^o 2 (juin 1997) : 322. http://dx.doi.org/10.1017/s0140525x97421441.

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Plamondon & Alimi propose a universal account of trajectory formation and speed/accuracy trade-off in rapid movements but fail, because: (1) the kinematic model ignores the more fundamental dynamics of movement generation, and (2) it does not capture the essential space-time constraints of movement accuracy. Hence, the modeling lacks a biologically and behaviorally principled foundation and is driven by pragmatic function fitting.

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Calabrò, Daniela. « Time, Space, Movement (abstract) ». Chiasmi International 3 (2001) : 373. http://dx.doi.org/10.5840/chiasmi2001366.

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Sherwood, David E. « Electromyographic Control of Movement Time in a Rapid Aiming Movement ». Perceptual and Motor Skills 107, n^o 2 (octobre 2008) : 353–64. http://dx.doi.org/10.2466/pms.107.2.353-364.

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One of the major issues to emerge from research on human-limb movement is the manner in which the central nervous system regulates electromyographic (EMG) activity to produce movements that differ in duration and distance. Different models of control predict different relations between EMC characteristics and movement kinematics, particularly with regard to the role of EMC burst duration and movement time. However, models have been evaluated with means averaged over individuals and across large numbers of practice trials. The goal of this study was to assess how well individual subjects' data conform to the predictions of the control models. Participants ( n = 4) performed an elbow flexion and extension task over 45° in movement times between 90 and 260 msec. EMG amplitude and EMG burst duration from the right elbow flexors were correlated with movement time for each individual. As expected, movement time was positively correlated with EMG burst duration and negatively correlated with EMG amplitude, with wider ranges in the EMG burst duration–movement time correlations across participants. Data from all participants supported predictions of the impulse-timing control model, but the slopes of the studied relations varied across participants.

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Sherwood, David E. « Movement Time Modulates Spatial Assimilation Effects in Rapid Bimanual Movements ». Research Quarterly for Exercise and Sport 75, n^o 2 (juin 2004) : 203–8. http://dx.doi.org/10.1080/02701367.2004.10609152.

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Phillips, Jim, et Denis Glencross. « The independence of reaction and movement time in programmed movements ». Acta Psychologica 59, n^o 3 (août 1985) : 209–25. http://dx.doi.org/10.1016/0001-6918(85)90045-9.

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TAN, MARCUS CHENG CHYE. « Moving Cage : Vibration, Sonification and the Quanta of Time ». Theatre Research International 46, n^o 2 (juillet 2021) : 169–83. http://dx.doi.org/10.1017/s0307883321000080.

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Dear John is an experimental choreomusical work that reinterprets Cage's works while advancing his ideas of sound as sonic events and embodied choreography. In this episodic work, improvised movement unfolds to a soundscape of defamiliarized instruments, sound devices and sonicities of macro- and micro-movements. The correspondence and (in)congruence between dance movements and music's kinetic energy become the means to examine a politics of the body and sound, of music on movement. Additionally, in this ‘auditory architecture’ the quanta of time, its relations and (lack of) unity are exposed. This article then examines the intersubjective interplay of movement and music, body and sonicity; it considers the resonance of the performing body as intermaterial vibration and how this invites a sonic politics of relational possibility. The article will then also investigate the ways in which the interaction of motion and music, movement and stillness engenders experiences of time's indeterminacy and elasticity.

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Thi Nguyen, Hong. « The Approach of Space-Time Cube to Visualizing Movement Data ». International Journal of Modeling and Optimization 5, n^o 3 (juin 2015) : 207–10. http://dx.doi.org/10.7763/ijmo.2015.v5.463.

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Lee, Irwin H., et John A. Assad. « Putaminal Activity for Simple Reactions or Self-Timed Movements ». Journal of Neurophysiology 89, n^o 5 (1 mai 2003) : 2528–37. http://dx.doi.org/10.1152/jn.01055.2002.

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To examine the role of basal ganglia-cortical circuits in movement initiation, we trained monkeys to make the same arm movements in two ways—in immediate reaction to a randomly timed external cue (cued movements) and also following a variable delay without an explicit initiation signal (self-timed movements). The two movement types were interleaved and balanced in overall timing to allow a direct comparison of activity before and during the movement. Posterior putaminal neurons generally had phasic, movement-related discharges that were comparable for cued and self-timed movements. On cued movements, neuronal activity increased sharply following cue onset. However, for self-timed movements, there was a slow build-up in activity that preceded the phasic discharge. This slow build-up was time-locked to movement and restricted to a narrow time window hundreds of milliseconds before movement. The difference in premovement activity between cued and self-timed trials was present before the earliest cue-onset times and was not related to any differences in the overall time-to-move between the two types of trials. These features suggest that activity evolving in the basal ganglia-cortical circuitry may drive the initiation of movements by increasing until an activity threshold is exceeded. The activity may increase abruptly in response to an external cue or gradually when the timing of movements is determined by the animals themselves rather than an external cue. In this view, small changes in activity that occur in advance of the much larger perimovement neuronal activity may be an important determinant of when movement occurs. In support of this hypothesis, we found that even for cued movements, faster reaction times were associated with slightly higher levels of activity hundreds of milliseconds before movement.

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Vukovic, Ognjen. « Time Optimal Control in Time Series Movement ». Journal of Applied Mathematics and Physics 03, n^o 09 (2015) : 1122–25. http://dx.doi.org/10.4236/jamp.2015.39139.

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Gros, Jeffrey. « Ecumenical Connections across Time : Medieval Franciscans as a Proto-Pentecostal Movement ? » Pneuma 34, n^o 1 (2012) : 75–93. http://dx.doi.org/10.1163/157007412x621725.

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Abstract In the long course of Christian history there have been many expressions of the action of the Holy Spirit in renewing the Christian Church through a variety of renewal movements. Two such movements are the twentieth-century Pentecostal movement and the thirteenth-century Franciscan movement. While there is no specific historical link one with the other, there are resources in the older movement, with its concern for direct human experience of Christ, its return to biblical poverty, a hope of renewing the church by a restoration of biblical holiness, its experience of gradually integrating its radical view of the end of time with the institutional church, and its impulsive missionary outreach, that offer many lessons for the newer movement as it serves worldwide Christianity.

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Zelaznik, Howard N., Brian Hawkins et Lorraine Kisselburgh. « The effects of movement distance and movement time on visual feedback processing in aimed hand movements ». Acta Psychologica 65, n^o 2 (juillet 1987) : 181–91. http://dx.doi.org/10.1016/0001-6918(87)90026-6.

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Kim, Ji-Eun, et David A. Nembhard. « Modeling the Effects of Time pressure and Feedback on Eye movements and Learning Performance ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 62, n^o 1 (septembre 2018) : 671–75. http://dx.doi.org/10.1177/1541931218621152.

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Eye movement measurement is both non-invasive to the learner, and available at a cost that is steadily decreasing. There are currently several mainstream laptop computers on the market that ship with fully integrated eye-tracking. Eye movements will take on a role as inputs to predict individualized learning performance. In response to the increased usage of this tool, this study uses eye-tracking technology to investigate the effects of time pressure and feedback on changes in eye movement by generating structural models. We tracked participants’ eye movement, and to relate this eye movement to human learning behaviors while participants were asked to complete online training for a Project Management task. The study measured participants’ eye-movements in response to the amount of time to deadlines and feedback updating the remaining time. Results showed that eye movement partially mediated the relationship between time to deadline and task completion time. The results of the study will be advantageous in predicting individualized learning performance based on eye movements.

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Kruchinina, Anna. « Optimal time task in saccadic eye movement ». Russian Journal of Biomechanics 24, n^o 1 (31 mars 2020) : 33–39. http://dx.doi.org/10.15593/rjbiomech/2020.1.04.

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This article is devoted to fast goal-directed human eye movements. Such movements are described in few ways. One of them is the time-optimal problem model. It this work, the saccade – fast single conformable ballistic eye movement, is under consideration. Saccadic eye trajectory is described by time-optimal task solution. Differential equations system are based on pendulum model. It defines control moment applied from extraocular muscles to eye globe and movement of it. Main feature of the system is all values in suggested system have physical meaning and were found in published experimental investigations. Consideration of the moment applied from extraocular muscles to eye glob as control is main difference of the system from other models for eye movement in submitted works. In this case, the open-loop system has two real roots and one zero. The particular case of the ratio of real roots of 1:3 is analyzed in the article. As a result of modelling, trajectory characteristics closed to the saccades observed in experimental studies is obtained. On the basis of the constructed model, the parameters of the synthesized saccades were compared with the parameters obtained on the experimental sample. The obtained models can be used both for problems of physiology and medicine, and for constructing virtual reality environments. For example, when developing 3D interfaces, the use of a mathematical model makes it possible to optimize the elements arrangement using game theory.

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Maslovat, Dana, Nicola J. Hodges, Romeo Chua et Ian M. Franks. « Motor preparation of spatially and temporally defined movements : evidence from startle ». Journal of Neurophysiology 106, n^o 2 (août 2011) : 885–94. http://dx.doi.org/10.1152/jn.00166.2011.

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Previous research has shown that the preparation of a spatially targeted movement performed at maximal speed is different from that of a temporally constrained movement ( Gottlieb et al. 1989b ). In the current study, we directly examined preparation differences in temporally vs. spatially defined movements through the use of a startling stimulus and manipulation of the task goals. Participants performed arm extension movements to one of three spatial targets (20°, 40°, 60°) and an arm extension movement of 20° at three movement speeds (slow, moderate, fast). All movements were performed in a blocked, simple reaction time paradigm, with trials involving a startling stimulus (124 dB) interspersed randomly with control trials. As predicted, spatial movements were modulated by agonist duration and timed movements were modulated by agonist rise time. The startling stimulus triggered all movements at short latencies with a compression of the kinematic and electromyogram (EMG) profile such that they were performed faster than control trials. However, temporally constrained movements showed a differential effect of movement compression on startle trials such that the slowest movement showed the greatest temporal compression. The startling stimulus also decreased the relative timing between EMG bursts more for the 20° movement when it was defined by a temporal rather than spatial goal, which we attributed to the disruption of an internal timekeeper for the timed movements. These results confirm that temporally defined movements were prepared in a different manner from spatially defined movements and provide new information pertaining to these preparation differences.

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Dry, Helen Aristar. « THE MOVEMENT OF NARRATIVE TIME ». Journal of Literary Semantics 51, s1 (20 juillet 2009) : 1–35. http://dx.doi.org/10.1515/jls-2021-2043.

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Prager, Roger H. « Cross/ing : Time • Space • Movement ». African Arts 31, n^o 2 (1998) : 80. http://dx.doi.org/10.2307/3337524.

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Stelmach, George E., Noreen L. Goggin et Adela Garcia-colera. « Movement specification time with age ». Experimental Aging Research 13, n^o 1 (mars 1987) : 39–46. http://dx.doi.org/10.1080/03610738708259298.

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Prager, R. « CROSS/ING : TIME, SPACE, MOVEMENT ». Nka Journal of Contemporary African Art 1998, n^o 8 (1 mars 1998) : 52–53. http://dx.doi.org/10.1215/10757163-8-1-52.

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Mateo, Julio C., Robert H. Gilkey et Jeffrey L. Cowgill. « Effect of Variable Visual-Feedback Delay on Movement Time ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 51, n^o 19 (octobre 2007) : 1373–77. http://dx.doi.org/10.1177/154193120705101921.

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The effects of variable feedback delays on movement time were examined in a three-dimensional (3D) virtual environment. The participants' task was to use a 3D controller to position a cursor in targets as they appeared in a cubic workspace. Both the mean and standard deviation of the delay between the movement of the controller and the displayed position of the cursor were manipulated. In addition, the size of the targets and the distance between targets were varied. The results suggested that movement times are much more strongly affected by mean delay than by delay variability and that the effect of both variables is greatest during the closed-loop component of the movement. The results are discussed in relation to buffering strategies for reducing delay variability, Fitts' law, and other descriptions of aimed movements.

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Fabius, Jasper H., Alessio Fracasso, Tanja C. W. Nijboer et Stefan Van der Stigchel. « Time course of spatiotopic updating across saccades ». Proceedings of the National Academy of Sciences 116, n^o 6 (17 janvier 2019) : 2027–32. http://dx.doi.org/10.1073/pnas.1812210116.

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Humans move their eyes several times per second, yet we perceive the outside world as continuous despite the sudden disruptions created by each eye movement. To date, the mechanism that the brain employs to achieve visual continuity across eye movements remains unclear. While it has been proposed that the oculomotor system quickly updates and informs the visual system about the upcoming eye movement, behavioral studies investigating the time course of this updating suggest the involvement of a slow mechanism, estimated to take more than 500 ms to operate effectively. This is a surprisingly slow estimate, because both the visual system and the oculomotor system process information faster. If spatiotopic updating is indeed this slow, it cannot contribute to perceptual continuity, because it is outside the temporal regime of typical oculomotor behavior. Here, we argue that the behavioral paradigms that have been used previously are suboptimal to measure the speed of spatiotopic updating. In this study, we used a fast gaze-contingent paradigm, using high phi as a continuous stimulus across eye movements. We observed fast spatiotopic updating within 150 ms after stimulus onset. The results suggest the involvement of a fast updating mechanism that predictively influences visual perception after an eye movement. The temporal characteristics of this mechanism are compatible with the rate at which saccadic eye movements are typically observed in natural viewing.

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Yanagisawa, Takufumi, Masayuki Hirata, Youichi Saitoh, Tetsu Goto, Haruhiko Kishima, Ryohei Fukuma, Hiroshi Yokoi, Yukiyasu Kamitani et Toshiki Yoshimine. « Real-time control of a prosthetic hand using human electrocorticography signals ». Journal of Neurosurgery 114, n^o 6 (juin 2011) : 1715–22. http://dx.doi.org/10.3171/2011.1.jns101421.

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Object A brain-machine interface (BMI) offers patients with severe motor disabilities greater independence by controlling external devices such as prosthetic arms. Among the available signal sources for the BMI, electrocorticography (ECoG) provides a clinically feasible signal with long-term stability and low clinical risk. Although ECoG signals have been used to infer arm movements, no study has examined its use to control a prosthetic arm in real time. The authors present an integrated BMI system for the control of a prosthetic hand using ECoG signals in a patient who had suffered a stroke. This system used the power modulations of the ECoG signal that are characteristic during movements of the patient's hand and enabled control of the prosthetic hand with movements that mimicked the patient's hand movements. Methods A poststroke patient with subdural electrodes placed over his sensorimotor cortex performed 3 types of simple hand movements following a sound cue (calibration period). Time-frequency analysis was performed with the ECoG signals to select 3 frequency bands (1–8, 25–40, and 80–150 Hz) that revealed characteristic power modulation during the movements. Using these selected features, 2 classifiers (decoders) were trained to predict the movement state—that is, whether the patient was moving his hand or not—and the movement type based on a linear support vector machine. The decoding accuracy was compared among the 3 frequency bands to identify the most informative features. With the trained decoders, novel ECoG signals were decoded online while the patient performed the same task without cues (free-run period). According to the results of the real-time decoding, the prosthetic hand mimicked the patient's hand movements. Results Offline cross-validation analysis of the ECoG data measured during the calibration period revealed that the state and movement type of the patient's hand were predicted with an accuracy of 79.6% (chance 50%) and 68.3% (chance 33.3%), respectively. Using the trained decoders, the onset of the hand movement was detected within 0.37 ± 0.29 seconds of the actual movement. At the detected onset timing, the type of movement was inferred with an accuracy of 69.2%. In the free-run period, the patient's hand movements were faithfully mimicked by the prosthetic hand in real time. Conclusions The present integrated BMI system successfully decoded the hand movements of a poststroke patient and controlled a prosthetic hand in real time. This success paves the way for the restoration of the patient's motor function using a prosthetic arm controlled by a BMI using ECoG signals.

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Bakaev, Maxim, et Hong-In Cheng. « Movement Time and Reaction Time of the Elderly ». Japanese journal of ergonomics 42 (2006) : 566–69. http://dx.doi.org/10.5100/jje.42.supplement_566.

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Hartlage, L. C., et J. S. Roth. « Reaction time/movement time enhancement of neuropsychological assessment ». Archives of Clinical Neuropsychology 14, n^o 1 (1 janvier 1999) : 31. http://dx.doi.org/10.1093/arclin/14.1.31a.

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Kaun, Anne. « ‘Our time to act has come’ : desynchronization, social media time and protest movements ». Media, Culture & ; Society 39, n^o 4 (21 avril 2016) : 469–86. http://dx.doi.org/10.1177/0163443716646178.

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Protest movements have successfully adopted media technologies to promote their causes and mobilize large numbers of supporters. Especially social media that are considered as low-cost and time-saving alternatives have played particularly important roles in recent mobilizations. There is, however, a growing concern about the contradictions between long-term organizing for progressive, social change, on one hand, and the media technologies employed, on the other. Hartmut Rosa has argued that the current culture of accelerated capitalism is characterized by a growing desynchronization between political practices (slow politics) and the economic system (fast capitalism). This article traces the increasing social acceleration related to (media) technologies employed by protest activists and asks whether there is an increasing desynchronization with their political practices discernible. Furthermore, the article investigates strategies of resistance to overcome the growing gap between ‘machine time’ and political time. Empirically, the article builds on archival material and in-depth interviews documenting the media practices of the unemployed workers’ movement (1930s), the tenants’ movement (1970s) and the Occupy Wall Street Movement (2011/2012) and argues for the need to re-politicize media infrastructures as means of communication in order to tackle democratic problems that emerge from the divergent temporalities.

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SHERWOOD, DAVlD E. « ELECTROMYOGRAPHIC CONTROL OF MOVEMENT TIME IN A RAPID AIMING MOVEMENT ». Perceptual and Motor Skills 107, n^o 6 (2008) : 353. http://dx.doi.org/10.2466/pms.107.6.353-364.

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Mink, J. W., et W. T. Thach. « Basal ganglia motor control. III. Pallidal ablation : normal reaction time, muscle cocontraction, and slow movement ». Journal of Neurophysiology 65, n^o 2 (1 février 1991) : 330–51. http://dx.doi.org/10.1152/jn.1991.65.2.330.

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1. Inactivation of the portions of globus pallidus pars interna (GPi) containing the greatest concentration of wrist-related neurons was achieved in two rhesus monkeys with microinjections of muscimol (temporary) and kainic acid (permanent). 2. After muscimol injection, there was onset within 30 s of 1) tonic and phasic coactivation of wrist flexors and extensors; 2) slightly greater activation of the flexors, giving a flexor bias in postural holds and the endpoint of movements; and 3) slowness of all movements with a prolonged movement time. Nevertheless, 4) movements made by lessening prior loaded muscle activity (to move in the direction of the load) were slower than movement made by increasing muscle activity (to move against the direction of the load). Despite marked slowing of all movements, there was 5) a normal reaction time for movement onset. Finally, there was 6) a reduced amplitude of most movements. Open room behavior included 7) spiraling contralateral to the lesion while walking. Effects were reproducible (12 injections), were apparent for 7-8 h and were usually completely gone by the next day's testing. 3. After kainic acid injection, there was a period of mixed effects, followed by a period of permanent defects (observed for up to 24 days) that duplicated the temporary effects of muscimol. 4. By contrast, muscimol inactivation of the cerebellar dentate nucleus resulted in 1) a prolonged reaction time and 2) an increased variability of movement trajectory, but 3) without change in movement time or peak velocity. Open room behavior included overshoot in reaching for fruit with the forelimb ipsilateral to the injection. 5. From the facts that normal pallidal neurons fire constantly, that pallidal neurons inhibit their target neurons, and that the muscimol effect was immediate, we conclude that the release of the target neurons from the tonic inhibition allowed them to fire in patterns that promoted a maintained state of cocontraction of agonist and antagonist muscles. From the fact that movement time was prolonged, we conclude that the maintained state of neural activity that caused the muscle cocontraction interfered with the commands for voluntary movement, which were generated by other mechanisms. From the fact that reaction time for movement onset was normal, we conclude that the pallidal neurons may play little or no role in the voluntary initiation of these movements, which are instead generated by other structures that include the anterior cerebral cortex and the lateral cerebellum.

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Schmidt, Richard A. « Movement Time, Movement Distance, and Movement Accuracy : A Reply to Newell, Carlton and Kim ». Human Performance 7, n^o 1 (mars 1994) : 23–28. http://dx.doi.org/10.1207/s15327043hup0701_2.

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Berret, Bastien, et Gabriel Baud-Bovy. « Evidence for a cost of time in the invigoration of isometric reaching movements ». Journal of Neurophysiology 127, n^o 3 (1 mars 2022) : 689–701. http://dx.doi.org/10.1152/jn.00536.2021.

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Movement vigor is generally thought to result from a trade-off between time and motor costs. However, it remains unclear whether the time cost only modulates vigor around some nominal value explained by a minimal motor cost or whether it determines movement invigoration more broadly. Here, we present an original paradigm allowing us to neutralize the cost of movement and provide new evidence that a cost of time must underlie the invigoration of isometric reaching movements.

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Li, Xue, et Yaqi Yang. « Development of Interactive Teaching of Physical Dance Based on Dynamic Time Reversion Technique ». Mathematical Problems in Engineering 2022 (6 juillet 2022) : 1–8. http://dx.doi.org/10.1155/2022/5697041.

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In order to cultivate students’ dance expression, in physical dance teaching, emphasis should be placed on cultivating students’ interest in physical dance, strengthening the training of movement skills and musical rhythm, training of cultural cultivation, and training of coordination and cooperation between male and female partners. In this paper, we design a dance teaching aid based on DTW (Dynamic Time Warping) movement similarity evaluation algorithm. The evaluation of movement similarity is difficult because each movement is multidimensional, there is a lot of noise when the movement data are collected, and there is high variability in the performance of different individuals, and the real-time requirement of movement similarity evaluation. In the teaching practice, we should pay attention to the cultivation of students’ dance expression, so that students can match the music and make coordinated sports dance movements, realize the integration of music and dance, and improve the professional standard.

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Neretina, S. S. « Turning Time ». Политическая концептология : журнал метадисциплинарных исследований, n^o 1 (31 mars 2023) : 45–56. http://dx.doi.org/10.18522/2949-0707.2023.1.4556.

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The article will focus on the beginning of the dissident movement, the sprouts of which appeared at the end of World War II, and on the difference between the first opposition groups to the dissident movement of the 1960s. The first groups are the student “Brotherhood of Beggars of Sybarites” which appeared in 1945 and a group of professional historians Krasnopevtsev-Rendel who tried to theoretically deal with the processes taking place in the USSR. In this sense, the novel by N.N. Williams “The Island of GNIPI” and the article by Krasnopevtsev “The main points of the development of the Russian revolutionary movement” are of interest. The dissident movement that emerged in the Sixties differed from the first opposition groups in that it was essentially moral and ethical, deeply personal, not systemically theoretical. In this regard, between the movement of the late 50s and 60s of the twentieth century. there is no continuity, and therefore it seems wrong to bring both under the general term “dissidence”: although both of them disagreed, they proceeded from different principles. It's more of a generational gap.

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Donnet, Sophie, Ramon Bartolo, José Maria Fernandes, João Paulo Silva Cunha, Luis Prado et Hugo Merchant. « Monkeys time their pauses of movement and not their movement-kinematics during a synchronization-continuation rhythmic task ». Journal of Neurophysiology 111, n^o 10 (15 mai 2014) : 2138–49. http://dx.doi.org/10.1152/jn.00802.2013.

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A critical question in tapping behavior is to understand whether the temporal control is exerted on the duration and trajectory of the downward-upward hand movement or on the pause between hand movements. In the present study, we determined the duration of both the movement execution and pauses of monkeys performing a synchronization-continuation task (SCT), using the speed profile of their tapping behavior. We found a linear increase in the variance of pause-duration as a function of interval, while the variance of the motor implementation was relatively constant across intervals. In fact, 96% of the variability of the duration of a complete tapping cycle (pause + movement) was due to the variability of the pause duration. In addition, we performed a Bayesian model selection to determine the effect of interval duration (450–1,000 ms), serial-order (1–6 produced intervals), task phase (sensory cued or internally driven), and marker modality (auditory or visual) on the duration of the movement-pause and tapping movement. The results showed that the most important parameter used to successfully perform the SCT was the control of the pause duration. We also found that the kinematics of the tapping movements was concordant with a stereotyped ballistic control of the hand pressing the push-button. The present findings support the idea that monkeys used an explicit timing strategy to perform the SCT, where a dedicated timing mechanism controlled the duration of the pauses of movement, while also triggered the execution of fixed movements across each interval of the rhythmic sequence.

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Ghozlan, A., et D. Widlocher. « Decision Time and Movement Time : Differential Effects of Practice ». Perceptual and Motor Skills 65, n^o 2 (octobre 1987) : 355–58. http://dx.doi.org/10.2466/pms.1987.65.2.355.

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Choice Reaction Time involves at least two components of response latency, Decision Time and Movement Time. Studies usually report values for these two components averaged over a definite number of trials. The aims of this study were to investigate the pattern of behaviour of the two components across the trials and the effect of repeating the experimental procedure two weeks later. 16 control subjects were given two sessions of 50 trials each. In Session 1 (D.0), the two components behave quite differently across the trials; there was no significant change in decision time, but a significant reduction in movement time occurred. Decision and movement time show no relationship. In Session 2 (D.15), a different pattern was found; movement time was still significantly reduced across trials but there was also a significant increase in decision time so the two components exhibit a negative relationship. Comparison of values from Sessions 1 and 2 shows an effect is found only on the first 10 trials for both components, the values of decision and movement times being smaller in Session 2 than Session 1.

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Kennefick, Michael, Joel S. Burma, Paul van Donkelaar et Chris J. McNeil. « The Time Course of Motoneuronal Excitability during the Preparation of Complex Movements ». Journal of Cognitive Neuroscience 31, n^o 6 (juin 2019) : 781–90. http://dx.doi.org/10.1162/jocn_a_01394.

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For a simple RT task, movement complexity increases RT and also corticospinal excitability, as measured by the motor evoked potential (MEP) elicited by TMS of the motor cortex. However, it is unknown if complexity-related increases in corticospinal excitability during the preparation of movement are mediated at the cortical or spinal level. The purposes of this study were to establish a time course of motoneuronal excitability before prime mover activation and to assess task-dependent effects of complex movements on motoneuronal and cortical excitability in a simple RT paradigm. It was hypothesized that motoneuronal and cortical excitability would increase before prime mover activation and in response to movement complexity. In a seated position, participants completed ballistic elbow extension/flexion movements with their dominant arm to one, two, or three targets. TMS and transmastoid stimulation (TS) were delivered at 0%, 70%, 80% or 90% of mean premotor RT for each complexity level. Stimulus intensities were set to elicit MEPs and cervicomedullary MEPs (CMEPs) of ∼10% of the maximal M-wave in the triceps brachii. Compared with 0% RT, motoneuronal excitability (CMEP amplitude) was already 10% greater at 70% RT. CMEP amplitude also increased with movement complexity as both the two- and three-movement conditions had greater motoneuronal excitability than the one-movement condition ( p < .038). Importantly, when normalized to the CMEP, there was no increase in MEP amplitude. This suggests that complexity-related increases in corticospinal excitability are likely to be mediated more by increased excitability at a motoneuronal than cortical level.

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Lowery, Curtis, William Russell, Jr., Patrick Baggot, James Wilson, Robert Walls, Lynn Bentz et Pam Murphy. « Time Quantified Detection of Fetal Movements Using a New Fetal Movement Algorithm ». American Journal of Perinatology 14, n^o 01 (janvier 1997) : 7–12. http://dx.doi.org/10.1055/s-2007-994088.

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Chen, Robert, et Mark Hallett. « The Time Course of Changes in Motor Cortex Excitability Associated with Voluntary Movement ». Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 26, n^o 3 (novembre 1999) : 163–69. http://dx.doi.org/10.1017/s0317167100000196.

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The excitability of the motor cortex is modulated before and after voluntary movements. Transcranial magnetic stimulation studies showed increased corticospinal excitability from about 80 and 100 ms before EMG onset for simple reaction time and self-paced movements, respectively. Following voluntary movements, there are two phases of increased corticospinal excitability from 0 to approximately 100 ms and from approximately 100 to 160 ms after EMG offset. The first phase may correspond to the frontal peak of motor potential in movement-related cortical potentials studies and the movement-evoked magnetic field I (MEFI) in magnetoencephalographic (MEG) studies, and likely represents a time when decreasing output from the motor cortex falls below that required for activation of spinal motoneurons, but is still above resting levels. The second phase of increased corticospinal excitability may be due to peripheral proprioceptive inputs or may be centrally programmed representing a subthreshold, second agonist burst. This may correspond to the MEFII in MEG studies. Corticospinal excitability was reduced below baseline levels from about 500 to 1,000 ms after EMG offset, similar to the timing of increase in the power (event-related synchronization, ERS) of motor cortical rhythm. Similarly, motor cortex excitability is reduced at the time of ERS of motor cortical rhythm following median nerve stimulation. These findings support the hypothesis that ERS represents an inactive, idling state of the cortex. The time course of cortical activation is abnormal in movement disorders such as Parkinson’s disease and dystonia, reflecting abnormalities in both movement preparation and in cortical excitability following movement.

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Pedersen, Scott J., et Paul R. Surburg. « Effect of Stimulant Medication on Lower Extremity Response Time of Boys with Attention Deficit Hyperactivity Disorder ». Perceptual and Motor Skills 101, n^o 2 (octobre 2005) : 401–7. http://dx.doi.org/10.2466/pms.101.2.401-407.

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Children with attention deficit hyperactivity disorder (ADHD) have been labeled as “inefficient movers”; however, little research has examined the effect of stimulant medication on lower extremity movements. 16 boys, 11 to 13 years old, with ADHD performed a lower-limb choice-response time task, both on and off medication. When nonmedicated, children had significantly slower reaction times to all three targets and significantly slower movement times for the contralateral and midline movements. For both conditions, children had significantly faster movement time when using the right leg than the left leg. These findings suggest that movement characteristics of children with ADHD are different under medicated and nonmedicated situations.

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Šlajpah, Sebastjan, Eva Čebašek, Marko Munih et Matjaž Mihelj. « Time-Based and Path-Based Analysis of Upper-Limb Movements during Activities of Daily Living ». Sensors 23, n^o 3 (23 janvier 2023) : 1289. http://dx.doi.org/10.3390/s23031289.

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Patients after stroke need to re-learn functional movements required for independent living throughout the rehabilitation process. In the study, we used a wearable sensory system for monitoring the movement of the upper limbs while performing activities of daily living. We implemented time-based and path-based segmentation of movement trajectories and muscle activity to quantify the activities of the unaffected and the affected upper limbs. While time-based segmentation splits the trajectory in quants of equal duration, path-based segmentation isolates completed movements. We analyzed the hand movement path and forearm muscle activity and introduced a bimanual movement parameter, which enables differentiation between unimanual and bimanual activities. The approach was validated in a study that included a healthy subject and seven patients after stroke with different levels of disabilities. Path-based segmentation provides a more detailed and comprehensive evaluation of upper limb activities, while time-based segmentation is more suitable for real-time assessment and providing feedback to patients. Bimanual movement parameter effectively differentiates between different levels of upper limb involvement and is a clear indicator of the activity of the affected limb relative to the unaffected limb.

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Du, Jun Min, et Hai Wen Shi. « Improving on Human’s Movement Time Model for Pointing Task - Introducing the Target Position Factor into Fitts’ Law ». Advanced Materials Research 433-440 (janvier 2012) : 2349–55. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.2349.

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The experiments were aimed at determining the effect of target position on movement time when performing a target pointing movement task. 21 subjects performed pointing movements with 72 conditions of various target position. The movement time data were collected. It was shown that the starting point position and target position greatly affect the movement time. As a result, the movement times were not explained satisfactorily by the conventional Fitts’ model. The conventional model was improved by introducing the target position factor into. Compared with the conventional Fitts’ model, the new model could describe the data better, both in term of contribution value (r2) and the standard error of the residual between the predicted value by model fit and the measured movement time.

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Effendi, Yusuf, Yosi Kristian, Lukman Zaman P.C.S.W et Hariadi Yutanto. « Pemanfaatan Mediapipe Body Pose Estimation dan Dynamic Time Warping untuk Pembelajaran Tari Remo ». Jurnal Teknologi dan Manajemen Informatika 9, n^o 2 (27 décembre 2023) : 183–90. http://dx.doi.org/10.26905/jtmi.v9i2.10408.

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Video can be used as a learning medium for various purposes. In this research, the object of study is the movements of the traditional dance "remo." Thus, as a substitute for an absent coach or instructor, videos can take on the role of a dance instructor. However, video communication is one-way between the coach and the learners. Without movement correction, individuals trying to learn remo dance may find it challenging to determine if they are performing the movements correctly. Therefore, the author aims to create a system to assist coaches in correcting the dance movements of their learners. Using the MediaPipe module and the Dynamic Time Warping algorithm, the author developed a system to correct the learners' dance movements. This system can detect deviations from the coach's instructional video and provide notifications about which body angles do not match the coach's video instructions. The system operates by having users upload a video of their dance movements, and then it identifies which movements deviate from the correct remo dance. The accuracy is measured by comparing the angle distances between the master's movements and the test data. If the angle exceeds a predetermined threshold, the movement is considered incorrect. The system's output is validated by the coach, and it achieves 90% accuracy in identifying movement errors in videos. With this accuracy, the system can assist coaches in evaluating their learners' remo dance movements.

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Chan, Alan H. S., et Errol R. Hoffmann. « Effect of movement direction and sitting/standing on leg movement time ». International Journal of Industrial Ergonomics 47 (mai 2015) : 30–36. http://dx.doi.org/10.1016/j.ergon.2015.02.003.

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Schultz, W., A. Studer, R. Romo, E. Sundstrom, G. Jonsson et E. Scarnati. « Deficits in reaction times and movement times as correlates of hypokinesia in monkeys with MPTP-induced striatal dopamine depletion ». Journal of Neurophysiology 61, n^o 3 (1 mars 1989) : 651–68. http://dx.doi.org/10.1152/jn.1989.61.3.651.

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1. We quantitatively assessed deficits in the initiation and execution of arm movements occurring after destruction of nigrostriatal dopamine neurons by systemic administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) (Sigma). Three monkeys performed a reaction time task in which they reached toward a single and constant target for food reward. 2. After administration of MPTP, all three monkeys showed hypokinesia necessitating dopamine precursor or receptor agonist treatment. The partial recovery of one animal from initial akinesia after 19 days permitted discontinuation of dopaminergic drug therapy, although marked hypokinesia remained present. The two other animals displayed additional, intermittent phases of rigidity and activation tremor and needed continuous dopaminergic drug therapy for most of the postlesion period. 3. Administration of MPTP significantly prolonged EMG reaction time in prime mover muscles and arm movement reaction time by 47-225% and 18-129%, respectively, on the six sides of the three animals, compared with control measurements before the lesion. EMG and arm movement reaction time increased over consecutive trials in most sessions comprising 110–130 movements, the first 20 movements showing almost normal values. The delay time between onsets of EMG and arm movement showed unsystematic changes. These deficits in movement initiation were observed both with and without dopamine precursor therapy. They lasted during the whole testing period of several months. 4. Linear correlations between arm movement onset and EMG onset in the two prime mover muscles, the extensor digitorum communis and the biceps, showed coefficients of mostly 0.7–0.9, both before and after MPTP. These data suggest that the temporal relationship between onsets of arm movement and EMG were not substantially affected by MPTP. 5. Arm movement time was divided into two phases. The duration of movement between the resting key and the target, a small food-containing box located ahead of the animal, was denoted as reaching movement time. The following hand manipulation inside the food box was measured as box movement time. After MPTP, both measures were significantly prolonged by 10-103% and 12–251%, respectively, on the six sides of the three monkeys. These deficits in movement execution were observed both with and without dopaminergic drug therapy and during the whole testing period. 6. Task performance after MPTP treatment was studied in one monkey in the absence of dopaminergic drug therapy. EMG and arm movement reaction times recovered partially over several weeks, while the prolongations in reaching and box movement times remained unchanged.(ABSTRACT TRUNCATED AT 400 WORDS)

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Bohannon, Richard W. « Stopwatch for Measuring Thumb-Movement Time ». Perceptual and Motor Skills 81, n^o 1 (août 1995) : 211–16. http://dx.doi.org/10.2466/pms.1995.81.1.211.

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The feasibility of using a stopwatch to measure thumb-movement time was examined. The measurements, which did not differ significantly between the nondominant and dominant hands, possessed high intrasession reliability. The measurements discriminated between 19 apparently healthy individuals and 19 older patients with a variety of diagnoses.

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