Movement-related phasic muscle activation. I. Relations with temporal profile of movement

1990 ◽  
Vol 63 (3) ◽  
pp. 455-464 ◽  
Author(s):  
S. H. Brown ◽  
J. D. Cooke
Keyword(s):  
Muscle Activation ◽  
Temporal Structure ◽  
Temporal Properties ◽  
Human Arm ◽  
Acceleration And Deceleration ◽  
Simple Scaling ◽  
Temporal Structures ◽  
Movement Parameters ◽  
Temporal Profiles

1. The role of phasic muscle activation in determining the temporal properties of human arm movements was studied. The experiments show that subjects can modulate the triphasic electromyographic (EMG) pattern to produce movements of varied temporal structures. 2. Subjects performed horizontal forearm movements in which they varied movement accelerations and decelerations. All movements were of the same amplitude, duration, and peak velocity. A phase-plane (velocity vs. position) template of the desired movement was presented to the subject, who had to reproduce the template by appropriate movement of the forearm. 3. The ratio of the durations of acceleration to deceleration (termed the symmetry ratio, SR) was used as a measure of the temporal structure of the movements. Movements with SRs ranging from 0.4 (short acceleration-long deceleration) to 2.0 (long acceleration-short deceleration) were studied. 4. Subjects modulated the components of the triphasic EMG pattern to produce movements with different temporal profiles. As the SR was increased (increasing acceleration duration-decreasing deceleration duration), the following changes occurred: 1) the duration of the initial agonist burst (AG1) increased while its magnitude decreased; 2) the antagonist burst (ANT1) was progressively delayed relative to movement onset. ANT1 magnitude increased while its duration remained constant; and 3) the magnitude of the second agonist burst (AG2) increased and its duration decreased. 5. The triphasic EMG pattern can be modified to produce movements whose velocity profiles are not the same under simple scaling of duration or magnitude. It is concluded that previously described relations between components of the triphasic EMG pattern and movement parameters, such as amplitude, speed, and duration, are secondary to associated changes in their acceleration and deceleration characteristics.

Movement-related phasic muscle activation. II. Generation and functional role of the triphasic pattern

1990 ◽  
Vol 63 (3) ◽  
pp. 465-472 ◽  
Author(s):  
J. D. Cooke ◽  
S. H. Brown
Keyword(s):  
Constant Velocity ◽  
Muscle Activation ◽  
Movement Control ◽  
Basic Unit ◽  
Emg Activity ◽  
Long Duration ◽  
Acceleration And Deceleration ◽  
Tracking Movements ◽  
Triphasic Pattern

1. Electromyographic (EMG) activity of arm movements made at constant velocity was studied in humans. In these movements, acceleration was temporally separated from deceleration by a period of constant velocity (zero acceleration) lasting up to 600 ms. 2. Agonist (AG1) and antagonist (ANT1) bursts were associated with acceleration. AG1 began before acceleration onset. ANT1 started after the onset of AG1 and was often partially coextensive with AG1. The initial phasic activity was followed by tonic EMG activity during the constant-velocity phase of the movements. Movement deceleration was associated with an antagonist burst (ANT2) and an agonist (AG2) burst. 3. Subjects could alter the magnitudes of the acceleration- and deceleration-related activities independently, with resulting independent changes in the movement acceleration and deceleration. 4. When the duration of the constant-velocity phase was decreased, the agonist/antagonist burst pairs occurred progressively closer in time. When movement duration was decreased to the point at which the velocity profile resembled that of step-tracking movements, the four periods of phasic EMG activity formed the classic triphasic pattern. 5. Triphasic EMG patterns were occasionally seen at the beginning or end of long-duration, constant-velocity movements. When they occurred, these triphasic patterns were associated with an acceleration/deceleration pattern similar to that seen in step-tracking movements. 6. The data indicate that paired agonist/antagonist activation is the basic unit of movement control. The AG1/ANT1 burst pair determines the increase and decrease of acceleration, respectively, and the ANT2/AG2 burst pair the increase and decrease of deceleration. These muscle activation pairs can be combined as needed to produce movements having different temporal characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Unweaving the embodied nature of English temporal prepositions

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Javier A. Morras Cortés ◽  
Xu Wen
Keyword(s):  
Conceptual Metaphor ◽  
Temporal Structure ◽  
Weak Version ◽  
Conceptual Metaphor Theory ◽  
Temporal Reference ◽  
Temporal Semantics ◽  
Temporal Cognition ◽  
Metaphor Theory ◽  
Temporal Structures

Abstract The metaphor time is space (Lakoff & Johnson 1999) and the pervasiveness of metaphor and image-schematic structure in human conceptualization (Johnson 1987; Hampe 2005) have been widely accepted among cognitive scientists as constructs that help explain non-spatial and temporal linguistic constructions. However, Conceptual Metaphor Theory (CMT) might not be the whole story. While it is acceptable that moments in time can be construed as being analogous to points in space as in utterances such as at the corner vs. at 2:30, there seems to be much more temporal cognition than previously thought. It turns out that time exhibits its own structure (following Evans 2004, 2013; Galton 2011) that is based on transience. This idea has made some scholars support the weak version of CMT which posits that the temporal meaning of prepositions is represented and processed independently of the corresponding spatial meanings (see Kemmerer 2005 for such a view). The present article supports the idea that spatial and temporal structures complement each other in order to achieve temporal conceptions. This is indeed a conceptual pattern showed by the English preposition at that makes use of an extrinsic temporal reference to activate its temporal semantics. To analyze the different temporal realizations that at may have, the paper aims to identify the topological structure that underlies the conceptual basis of this preposition. This allows us to appreciate how the spatio-conceptual structure of at partially structures temporal conceptions. The paper also identifies the nature of the temporal structure that is involved in temporal realizations. The article concludes with some remarks, among them the pivotal role of the schematic temporal structure that is captured by the extrinsic temporal reference, and the role of conceptual metaphor in underdetermining temporal thinking.

scholarly journals Quantitative analysis of temporal structure in Cuban guaguancó drumming

2018 ◽  
Vol 1 ◽  
pp. 205920431878264 ◽  
Author(s):  
Fernando Benadon ◽  
Andrew McGraw ◽  
Michael Robinson
Keyword(s):  
Quantitative Analysis ◽  
Temporal Structure ◽  
Principal Component ◽  
Music Notation ◽  
Expert Performance ◽  
Temporal Properties ◽  
Different Types ◽  
Santiago De Cuba ◽  
Shed Light

We examine the temporal properties of cyclical drumming patterns in an expert performance of Afro-Cuban rumba recorded in Santiago de Cuba. Quantitative analysis of over 9,000 percussion onsets collected from custom sensors placed on various instruments reveals different types and degrees of rhythmic variation across repetitions of each of five characteristic guaguancó patterns (clave, cascara, quinto, segundo, and tumba). We assess each instrument’s variability using principal component analysis and multidimensional scaling, complementing our quantitative exploration with insights from music theory. Through these methods, we uncover details of timing that are insufficiently conveyed with standard music notation in order to shed light on the role of improvised variation in solo and accompaniment ensemble roles.

Cross-correlation between Auditory and Visual Signals Promotes Multisensory Integration

2013 ◽  
Vol 26 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Cesare V. Parise ◽  
Vanessa Harrar ◽  
Marc O. Ernst ◽  
Charles Spence
Keyword(s):  
Multisensory Integration ◽  
Cross Correlation ◽  
Temporal Structure ◽  
Temporal Correlation ◽  
Visual Signals ◽  
Lower Sensitivity ◽  
Correspondence Problem ◽  
Temporal Structures ◽  
The Cross

Humans are equipped with multiple sensory channels that provide both redundant and complementary information about the objects and events in the world around them. A primary challenge for the brain is therefore to solve the ‘correspondence problem’, that is, to bind those signals that likely originate from the same environmental source, while keeping separate those unisensory inputs that likely belong to different objects/events. Whether multiple signals have a common origin or not must, however, be inferred from the signals themselves through a causal inference process. Recent studies have demonstrated that cross-correlation, that is, the similarity in temporal structure between unimodal signals, represents a powerful cue for solving the correspondence problem in humans. Here we provide further evidence for the role of the temporal correlation between auditory and visual signals in multisensory integration. Capitalizing on the well-known fact that sensitivity to crossmodal conflict is inversely related to the strength of coupling between the signals, we measured sensitivity to crossmodal spatial conflicts as a function of the cross-correlation between the temporal structures of the audiovisual signals. Observers’ performance was systematically modulated by the cross-correlation, with lower sensitivity to crossmodal conflict being measured for correlated as compared to uncorrelated audiovisual signals. These results therefore provide support for the claim that cross-correlation promotes multisensory integration. A Bayesian framework is proposed to interpret the present results, whereby stimulus correlation is represented on the prior distribution of expected crossmodal co-occurrence.

Role of Cl− currents in rat aortic smooth muscle activation by prostaglandin F2α

2003 ◽  
Vol 481 (2-3) ◽  
pp. 133-140 ◽  
Author(s):  
Jihua Jiang ◽  
Peter H Backx ◽  
Hwee Teoh ◽  
Michael E Ward
Keyword(s):  
Smooth Muscle ◽  
Muscle Activation ◽  
Prostaglandin F2α ◽  
Aortic Smooth Muscle

Managing projects as a mode of temporal ordering. Performative organising of time and temporality in projects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yannick Kalff
Keyword(s):  
Empirical Data ◽  
Temporal Structure ◽  
Project Managers ◽  
Temporal Perspective ◽  
Content Type ◽  
Temporal Structures ◽  
Research Gap ◽  
Temporal Flow ◽  
Conceptual Nature ◽  
Temporal Ordering

Purpose Project studies analyse either managing practices or the temporal nature of project management, which leaves open a research gap: the temporality of managing practice. The paper demonstrates that performativity theory with a temporal perspective helps us to understand how managing a project organises limited temporal resources by aligning activities, deadlines or milestones to reach a goal in a given time.Design/methodology/approach The article utilises empirical data and grounded theory methodology. Ten interviews with project managers from two companies support empirically guided theory building and conceptual reasoning.Findings The article extends John Law's “modes of ordering” to a project-specific mode of temporal ordering. This mode of temporal ordering describes the underlying rationale of project managers who assign, order and materialise time to generate the temporal structure of the project.Research limitations/implications The conceptual nature of the paper and its limited empirical data restrict the generalisation of the findings. The article's goal is to initiate further research and to offer a set of tools for such research.Originality/value The contribution links managing practice and temporality in a performativity approach. This link focusses the actual actions of the managers and contextualises them in the temporal flow of the project. Managing projects as a mode of temporal ordering describes how project managers enact temporal structures and how they themselves and their activities are temporally embedded.

scholarly journals Neuromuscular, Perceptual, and Temporal Determinants of Movement Patterns in Wheelchair Fencing: Preliminary Study

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Zbigniew Borysiuk ◽  
Tadeusz Nowicki ◽  
Katarzyna Piechota ◽  
Monika Błaszczyszyn
Keyword(s):  
Latissimus Dorsi ◽  
Muscle Activation ◽  
Movement Pattern ◽  
Intergroup Difference ◽  
Wireless System ◽  
Sensory Stimuli ◽  
Accelerometer Signal ◽  
Postural Muscle ◽  
Preliminary Study

The objective of the present study was to determine the structure of the movement pattern performed during a wheelchair fencing lunge that is executed in response to visual and sensory stimuli. In addition, a comparison was made between fencers in the categories A and B of disability. In addition, the analysis involved the correlation between the duration of the sensorimotor response and the value of the bioelectric signal recorded in selected muscles. Seven Paralympic team athletes specializing in wheelchair fencing (3 in category A and 4 in category B) participated in the research. The fencers perform at international level competitions and are multiple medalists of the Paralympic Games. In the study, a wireless system for sEMG and accelerometer signal measurement was employed to test the intervals between the initiation of the lunge attack and its termination defined by the touch of the weapon on the coach’s torso. The electrodes were placed on 9 key muscles responsible for the effectiveness of the executed attack: DEL, TRI, BC, ECR FCR, LD, and EAO. The significant intergroup difference in the muscle activation was found to be 0.333 s for category A fencers and 0.522 s for category A fencers at p=0.039 applies to the latissimus dorsi (LD LT) muscle, which demonstrates its significance as a postural muscle in the structure of the examined movement pattern. In terms of the values of EMG, a tendency for higher MVC (%) values in most muscles for category A competitors was recorded. The latissimus dorsi (DL RT) muscle with an intergroup difference of MVC-114.63 for cat. A and 67.50 for cat. B at p=0.039 turned out to play a significant role. The results prove the role of postural muscles: external abdominal oblique and latissimus dorsi on the effectiveness of the attacks executed in wheelchair fencing.

Distinct Intracellular Calcium Profiles Following Influx Through N- Versus L-Type Calcium Channels: Role of Ca2+-Induced Ca2+ Release

2004 ◽  
Vol 92 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Keith Tully ◽  
Steven N. Treistman
Keyword(s):  
Intracellular Calcium ◽  
Ryanodine Receptors ◽  
Decay Rates ◽  
Selective Activation ◽  
Intracellular Ca ◽  
Pheochromocytoma Pc12 ◽  
High Concentrations ◽  
Neuronal Functions ◽  
Temporal Profiles

Selective activation of neuronal functions by Ca2+ is determined by the kinetic profile of the intracellular calcium ([Ca2+]i) signal in addition to its amplitude. Concurrent electrophysiology and ratiometric calcium imaging were used to measure transmembrane Ca2+ current and the resulting rise and decay of [Ca2+]i in differentiated pheochromocytoma (PC12) cells. We show that equal amounts of Ca2+ entering through N-type and L-type voltage-gated Ca2+ channels result in significantly different [Ca2+]i temporal profiles. When the contribution of N-type channels was reduced by ω-conotoxin MVIIA treatment, a faster [Ca2+]i decay was observed. Conversely, when the contribution of L-type channels was reduced by nifedipine treatment, [Ca2+]i decay was slower. Potentiating L-type current with BayK8644, or inactivating N-type channels by shifting the holding potential to −40 mV, both resulted in a more rapid decay of [Ca2+]i. Channel-specific differences in [Ca2+]i decay rates were abolished by depleting intracellular Ca2+ stores with thapsigargin or by blocking ryanodine receptors with ryanodine, suggesting the involvement of Ca2+-induced Ca2+ release (CICR). Further support for involvement of CICR is provided by the demonstration that caffeine slowed [Ca2+]i decay while ryanodine at high concentrations increased the rate of [Ca2+]i decay. We conclude that Ca2+ entering through N-type channels is amplified by ryanodine receptor mediated CICR. Channel-specific activation of CICR provides a mechanism whereby the kinetics of intracellular Ca2+ leaves a fingerprint of the route of entry, potentially encoding the selective activation of a subset of Ca2+-sensitive processes within the neuron.

Sign in / Sign up

Export Citation Format

Share Document