Amplitude‐ and instruction‐dependent modulation of movement‐related electromyogram activity in humans.

Brown, Susan H.; Cooke, J. D.

doi:10.1113/jphysiol.1981.sp013775

Cited by 209 publications

(93 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This model emerged from initial studies examining targeted isometric force tracking tasks in cats (Ghez & Vicario, 1978a, 1978b and was later expanded to isometric studies in humans (Gordon & Ghez, 1984, 1987a, 1978b). Brown and Cooke extended this model to single joint movements (Brown & Cooke, 1981a, 1981b, an extension that was further validated by a number of studies Hoffman & Strick, 1986;Mustard & Lee, 1987;Krakauer, Gordon, Veytsman, & Ghez, 2002;. The pulse-step model proposes that rapid limb movements are governed by an initial pulsatile output that determines the amplitude and duration of the initial acceleration impulse.…”

Section: Introductionmentioning

confidence: 99%

“…Intended distance and velocity are thus thought to be specified by modifications in control pulse amplitude. Brown and Cooke (1981a, 1981b showed that acceleration amplitude is determined by initial agonist burst amplitude, and that both measures are resistant to peripheral sensory events evoked by mechanical perturbations. They concluded that pulse-height control is largely due to preplanning processes.…”

Section: Introductionmentioning

confidence: 99%

“…The pulse-step model also includes modulation of the width of the initial pulse, which is reflected by agonist EMG burst duration, antagonist burst latency and force, torque, or acceleration duration (Brown & Cooke, 1981a, 1981bGordon & Ghez, 1987b). In a targeted isometric task, Ghez (1984, 1987a, b) reported negative correlations between peak force (pulse-height) and force rise time (pulse-width), when data were assessed within a single force target.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Control of velocity and position in single joint movements

Mutha

Sainburg

2007

Human Movement Science

View full text Add to dashboard Cite

Previous research on single joint movements has lead to the development of models of control that propose that movement speed and distance are controlled through an initial pulsatile signal that can be modified in both amplitude and duration. However, the manner in which the amplitude and duration are modulated during the control of movement speed and distance remains controversial. We now report two studies that were designed to test and refine the pulse-step model of movement control. In our first study, participants move at a series of speeds to a single spatial target. In this task, acceleration duration (pulse-width) varied substantially across targets, and was negatively correlated with peak acceleration (pulse-height). In a second experiment, we removed the spatial target, but required movements at three speeds similar to those used in the first study. In this task, acceleration amplitude varied extensively across the speed targets, while acceleration duration remained constant across the three speeds. Taken together, our current findings demonstrate that pulse-width measures can be modulated independently from pulse-height measures, and that a positive correlation between such measures is not obligatory, even when sampled across a range of movement speeds. In addition, our findings suggest that pulse-height modulation plays a primary role in controlling movement speed and specifying target distance, whereas pulse-width mechanisms are employed to correct errors in pulse-height control, as required to achieve spatial precision in final limb position.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Control of velocity and position in single joint movements

Mutha

Sainburg

2007

Human Movement Science

View full text Add to dashboard Cite

show abstract

“…The electromyographic analysis of rapid (ballistic) goal-directed movements in man disclosed a distinctive triphasic activity pattern in a wide variety of antagonistic muscle pairs (Wacholder 1923;Hufschmidt 1952;Hopf et al 1973;Angel 1974;Hallett and Marsden 1973;Hallett et al 1975;Brown and Cooke 1981;Day and Marsden 1982;. Hallett et al (1975) postulated that the timing of this pattern was constant and that movements of different amplitudes were achieved by varying only the size of the bursts.…”

Section: Introductionmentioning

confidence: 99%

“…Time calibration applies to B, C, F, and G. Individual traces were aligned for averaging to a position trigger signal elicited at 2 ~ increased. The size and the timing of the burst appear to be subtly adjusted to the precise nature of the task by a highly versatile programme (Brown and Cooke 1981;Marsden et al 1983;Meinck et al 1984).…”

Section: Introductionmentioning

confidence: 99%

Rapid goal-directed elbow flexion movements: limitations of the speed control system due to neural constraints

1985

View full text Add to dashboard Cite

Summary.In rapid goal-directed elbow flexion movements the influence of both movement amplitude and inertial load on the three-burst pattern and the consequences on movement time were studied. Subjects performed visually guided, selfpaced movements as rapidly and as accurately as possible. An increase of both the movement amplitude and the inertial load were found to be interacting factors for the modulation of the threeburst-pattern and movement time. The first biceps burst progressively increased in duration and amplitude for larger movements, resulting in prolonged movement times. Surplus inertial loads further prolonged the agonist burst for large, but not for small movement amplitudes. The activity of the antagonist burst, in contrast, was largest in small movements and successively decreased at increasing movement amplitudes. Its duration, however, remained fairly constant. As was similarly observed for the agonist burst, surplus inertial loads lead to a prolongation of antagonist burst duration and an increase of the activity integral for large, but not for small movement amplitudes. It is suggested that in elbow flexion movements the programming of fastest goal-directed movements must take into account neural constraints and biomechanical characteristics of the agonist muscle and the antagonist muscle. Due to neural constraints of the biceps muscle, in contrast to finger movements, the concept of movement time invariance does not hold for elbow movements. Furthermore, neural constraints of the antagonist muscle lead to a limited force production of the agonist muscle at small movement amplitudes in order to avoid an overload of the braking process. The complexity of the relationship between neural and mechanical factors indicate that the size and * Supported by the Deutsche Forschungsgemeinschaft (SFB 33) Offprint requests to: R. Benecke (address see above)timing of the three-burst-pattern has to be subtly adjusted to the precise nature of the task and its biomechanical characteristics.

show abstract