A comparison of intra- and interpersonal interlimb coordination: coordination breakdowns and coupling strength

Intra- and interpersonal interlimb coordination of pendulums swung from the wrist was investigated. For both kinds of coordination, the steady state and breakdown of bimanual rhythmic coordination as indexed by the time series of the relative phase angle phi were studied under the manipulation of coordination mode, frequency of oscillation, and the difference in the eigenfrequencies (preferred tempos) of the individual oscillating limbs. The properties observed for both intra- and interpersonal coordination were those predicted by a dynamical model of rhythmic coordination that considers the coordinated limbs coupled to be nonlinear oscillators. Using a regression method, the coupling strengths of the coupled system were recovered. As predicted by the dynamical model, the strength of the dynamic was generally greater for the in-phase than the anti-phase mode and decreased with increasing frequency. Further, the strength of the interpersonal interlimb coupling was weaker than that of intrapersonal interlimb coupling.     

Disentangling the effects of attentional and amplitude asymmetries on relative phase dynamics.

Attentional asymmetry in rhythmic interlimb coordination induces an asymmetry in relative phase dynamics, allegedly reflecting an asymmetry in coupling strength. However, relative phase asymmetries may also be engendered by an attention-induced difference between the amplitudes (and hence the preferred frequencies) of the limb movements. The authors conducted 3 experiments to dissociate those (not mutually exclusive) potential effects. Controlled manipulations of amplitude disparity and attentional focus, both alone and combined, revealed that variations in amplitude disparity had the expected effects, but produced evidence against the currently prevailing interpretation that attentional asymmetry affects the relative phase dynamics through an asymmetry in coupling strength. Implications of these findings are discussed vis-à-vis recent empirical findings and extant dynamical models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation of muscular and spatial constraints on patterns of interlimb coordination.

Interlimb coordination is subject to constraints. One major constraint has been described as a tendency for homologous muscle groups to be activated simultaneously. Another has been described as a biasing of limb segments to movement in the same direction. In 2 experiments, the 2 constraints were placed in opposition: In-phase or antiphase contraction of homologous muscles of contralateral limbs produced movement that was spatially antiphase or in-phase, respectively. Probability distributions of relative phase were obtained under manipulations of phase detuning and movement speed. They revealed that the equilibrium and stability of coordination were related, respectively, to spatial relative phase and muscular relative phase. Previously observed spatial and muscular constraints reflect a (possibly very general) factorization of attractor location and attractor strength in the dynamics of interlimb coordination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dynamics of bimanual circle drawing

A bimanual circle drawing task was employed to elucidate the dynamics of intralimb and interlimb coordination. Right-handed subjects were required to produce circles with both hands in either a symmetrical (mirror) mode (i.e. one hand moving clockwise, the other counter-clockwise) or in an asymmetrical mode (i.e. both hands moving clockwise or counter-clockwise). The frequency of movement was scaled by an auditory metronome from 1.50 Hz to 3.25 Hz in 8 (8-sec) steps. In the asymmetrical mode, distortions of the movement trajectories, transient departures from the target pattern of coordination, and phase wandering were evidence as movement frequency was increased. These features suggested loss of stability. Deviations from circular trajectories were most prominent for movements of the left hand. Transient departures from the required mode of coordination were also largely precipitated by the left hand. The results are discussed with reference to manual asymmetries and mechanisms of interlimb and intersegmental coordination.     

Acquiring bimanual skills: Contrasting forms of information feedback for interlimb decoupling.

Addressed the learner's capability to perform different upper-limb actions simultaneously with the help of various sources of information feedback. An elbow flexion movement was made in the left limb together with a flexion-extension-flexion movement in the right limb. Interlimb interactions were assessed at the structural as well as the metrical level of movement specification during acquisition and retention. Despite a strong initial tendency for the limbs to be synchronized, findings revealed that Ss became gradually more successful in interlimb decoupling as a result of practice with augmented feedback. However, detailed knowledge of movement kinematics was no more effective than global outcome information for interlimb decoupling, indicating that knowledge of results may have more potential for acquiring multiple degree-of-freedom tasks than previously believed. Finally, the data support the general notion that learning new coordination tasks involves the suppression of preexisting preferred coordination tendencies, which is often a prerequisite for building new coordination modes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamical patterns in clapping behavior.

A nonlinear dynamics framework that has been applied successfully to several laboratory idealizations of rhythmic behaviors was applied to a more naturally occurring behavior, clapping. Inertial loading of limbs and frequency of oscillation were manipulated. Displacement of relative phase from perfectly in phase and the variability of relative phase, both of which are used as indexes of coordination dynamics, increased with greater inertial imbalance between limbs. Increasing frequency exaggerated these effects. These hallmark properties of coupled oscillator dynamics appeared whether or not the hands contacted, albeit with the latter condition revealing a significant asymmetry in the dynamics. Results highlight the generality of the coupled oscillator regime in interlimb coordination as well as its appropriateness for characterizing behaviors that involve contact of limb surfaces and suggest one way in which perceptual information may tune the dynamical regime. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Environmental coupling modulates the attractors of rhythmic coordination.

A simple instance of coupling behavior to the environment is oscillating the hands in pace with metronome beats. This environmental coupling can be weaker (1 beat per cycle) or stronger (2 beats per cycle). The authors examined whether strength of environmental coupling enhanced the stability of in-phase bimanual coordination. Detuning by manipulanda that produced different left and right eigenfrequencies shifted the relative phase angle from 0°, with the size of the shift larger for higher movement frequencies. Stronger environmental coupling was found to decrease this relative-phase shift, with accompanying increase and reduction, respectively, in recurrence quantification measures related to coordination stability and coordination noise. Stronger environmental coupling also increased oscillation amplitude. Results are considered from the perspective of parametric stabilization. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Spinal cord coordination of hindlimb movements in the turtle: intralimb temporal relationships during scratching and swimming

Hindlimb interlimb coordination was examined in turtles during symmetrical "same-form" behaviors in which both hindlimbs utilized the same movement strategy ("form") and during asymmetric "mixed-form" behaviors in which the form exhibited by one hindlimb differed from that of its contralateral partner. In spinal turtles, three forms of scratching were examined: rostral, pocket, and caudal. Bilateral symmetrical same-form scratching was studied for each of the forms. Asymmetric mixed-form scratching (rostral scratching of a hindlimb and pocket scratching of the other hindlimb) was also examined. In intact turtles, two forms of swimming were examined: forward swimming and back-paddling. The symmetrical behavior of bilateral forward same-form swimming and the asymmetric behavior of turning mixed-form swimming (forward swimming of 1 hindlimb and back-paddling of the other hindlimb) were studied. For all behaviors examined, most episodes displayed absolute or 1:1 coordination; in this type of coordination, during each movement cycle that began and ended with the onset of ipsilateral hip flexion, there was a single onset of contralateral hip flexion. For most of these episodes there was out-of-phase coordination between hip movements; the onset of contralateral hip flexion occurred near the onset of ipsilateral hip extension midway through the ipsilateral movement cycle. Bilateral caudal/caudal same-form scratching displayed out-of-phase 1:1 coordination during some episodes and in-phase 1:1 coordination during other episodes. During in-phase coordination, the onset of contralateral hip flexion occurred near the onset of ipsilateral hip flexion close to the start of the ipsilateral movement cycle. In a few cases of bilateral same-form scratching there were episodes of relative or 2:1 coordination; in this type of coordination, during each movement cycle of the slowly moving limb that began and ended with ipsilateral hip flexion, there were two distinct occurrences of the onset of contralateral hip flexion. The observation that out-of-phase movements of the hip occurred during symmetrical as well as asymmetric behaviors is consistent with the hypothesis that timing signals related to hip movement play a major role in interlimb phase control. The neural mechanisms responsible for interlimb phase control are not well understood in vertebrates. The present demonstration of bilateral scratching in spinal turtles suggests that this preparation may be suitable for additional experiments to examine mechanisms of vertebrate interlimb phase control.     

Effectiveness of two models of brief family education: retention of gains by family members of adults with serious mental illness

Interlimb coordination is directly relevant to the understanding of the neural control of locomotion, but few studies addressing this topic for nonhuman primates are available, and no data exist for any hominoid other than humans. As a follow-up to Jungers and Anapol's ([1985] Am. J. Phys. Anthropol. 67:89-97) analysis on a lemur and talapoin monkey, we describe here the patterns of interlimb coordination in two chimpanzees as revealed by electromyography. Like the lemur and talapoin monkey, ipsilateral limb coupling in chimpanzees is characterized by variability about preferred modes within individual gaits. During symmetrical gaits, limb coupling patterns in the chimpanzee are also influenced by kinematic differences in hindlimb placement ("overstriding"). These observations reflect the neurological constraints placed on locomotion but also emphasize the overall flexibility of locomotor neural mechanisms. Interlimb coordination patterns are also species-specific, exhibiting significant differences among primate taxa and between primates and cats. Interspecific differences may be suggestive of phylogenetic divergence in the basic mechanisms for neural control of locomotion, but do not preclude morphological explanations for observed differences in interlimb coordination across species.     

Coupling of breathing and movement during manual wheelchair propulsion.

The hypothesis of this study was that stable coordination patterns may be found both within and between physiological subsystems. Many studies have been conducted on both monofrequency and multifrequency coordination, with a focus on both the frequency and phase relations among the limbs. In the present study, locomotor-respiratory coupling was observed in the maintenance of small-integer frequency ratios (2:1, 3:1, and 4:1) and in the consistent placement of the inspiratory phase just after the onset of the movement cycle during wheelchair propulsion. Level of experience and various motor and respiratory parameters were manipulated. Coupling was observed across levels of experience. Increases in movement frequency were accompanied by a shift to larger-integer ratios, suggesting that a single modeling strategy (e.g., the Farey tree; D. L. González & O. Piro, 1985) may be used for coordination both within the motor subsystem and between it and other physiological subsystems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The developmental origins of bimanual coordination: A dynamic perspective.

Patterns of interlimb coordination associated with infant reaching fluctuate frequently over developmental time. This study investigated whether these fluctuations are related to coordination tendencies. Interlimb patterns were studied in reaching and nonreaching movements in 4 infants, which were followed through their 1st year. Each week, reaching and nonreaching endpoint kinematics were recorded in both arms during multiple 14-s trials. It was found that patterns of interlimb coordination in reaching matched coordination tendencies in nonreaching. Reaching fluctuated between uni- and bimanual periods. During the bimanual periods, nonreaching interlimb activity tended to be synchronous. During the unimanual periods, nonreaching activity revealed no predominant form of interlimb coordination. It is argued that changing coordination tendencies may influence the organization of specific goal-oriented behaviors from early in life. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Spatial coupling in the coordination of complex actions

The majority of investigations on coordinated action have focused on temporal constraints in movements. Recent studies have demonstrated spatial constraints when the hands produce different trajectory shapes simultaneously. The focus of the current study was to determine whether spatial coupling occurs in individual parameters of the actions, or whether the shapes per se undergo accommodation. Subjects were tested on a bimanual paradigm to investigate the nature of spatial constraints in complex tasks. Shape and size of the required trajectories were varied for two limbs. When trajectories that require different shapes were assigned to the two hands, disruption in the spatial characteristics of the trajectories was observed. Disruption in the global patterns of the trajectories could be described on the basis of coupling in individual parameters of action, direction, and amplitude, which could be inferred by decomposing the trajectories into orthogonal components. Amplitude accommodation in these orthogonal components of motion increased linearly with the difference in required amplitude for the two limbs. Interpretations of these effects suggest that directional coupling is a result of interference between two different response plans, whereas amplitude coupling may be related to either planning or execution variables. These results strongly suggest the need for further investigation of the spatial domain of complex coordinated action.     

Strategy differences in oscillatory tracking: Stimulus-hand versus stimulus-manipulandum coupling.

In 3 experiments, participants matched the rotations of a unimanually grasped wheel to a visual oscillation. Two coordination modes were studied: in-phase coordination (no phase difference between stimulus and movement) and anti-phase coordination (180 degrees phase difference). The hand grasped the wheel at either the 12:00 or the 6:00 position. Stimulus frequency, hand placement, phasing, and visibility (whether the hand and wheel were visible) all affected movement amplitude and stability. There were large individual difference especially at the 6:00 position; some participants appeared to couple movements of the wheel to stimulus oscillations, some coupled movements of the hand, and some did both. The results parallel stimulus-response compatibility effects in a similar choice reaction time task and reiterate J. A. S. Kelso's (1995) emphasis on studying intrinsic coupling dynamics at the level of the individual, where apparent differences in strategy can be observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crosslinked plasmalemmal cholesterol is sequestered to caveolae: analysis with a new cytochemical probe

The dynamic characteristics of horizontal convergence and divergence eye movement responses to symmetric stimuli were examined. Binocular eye movements were recorded in five, visually normal adult subjects using the infrared reflection technique for symmetric convergent and divergent blur-free, disparity-only, step stimuli of 2, 4, 8, 12, and 16 deg. The main sequence as well as other temporal parameters including latency, time-to-peak velocity, time constant, and total duration were analyzed. A number of fundamental differences in the response characteristics were found between convergence and divergence. First, the slope of the peak velocity vs amplitude curve was approximately twice as high for convergence than divergence. The results are consistent with neurophysiological findings in monkeys and most findings in humans. Second, the initial fast component for convergence exhibited a larger amplitude than for divergence. This may reflect differences in central neural gain for convergence and divergence. And, third, all temporally related components were shorter for convergence than divergence. These findings provide an overall framework for vergence control and suggest fundamental differences in neural processing delays and neural controller pathways for convergence and divergence.     

Specification of movement amplitudes for the left and right hands: Evidence for transient parametric coupling from overlapping-task performance.

Bimanual coordination tasks suggest transient cross-talk between concurrent specification processes for movements of the left and right hand that vanishes as the time for specification increases. In 2 experiments with overlapping and successive unimanual tasks, the hypothesis of transient coupling was examined for a psychological-refractory-period paradigm. Time for specification was manipulated by varying the delay between first and second signal (Experiment 1) and by precuing the first response (Experiment 2). Participants performed rapid reversal movements of same or different amplitudes with the left and right hands. With different amplitudes, reaction times (RTs) of the second responses were longer than with same amplitudes at short delays, and this disappeared at longer delays in Experiment 1. In Experiment 2, precuing also reduced the difference between RTs of second responses in same-amplitude and different-amplitude trials. These findings are consistent with the hypothesis of transient coupling during amplitude specification obtained with bimanual tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coupling dynamics in interlimb coordination.

In 1:1 frequency locking, the interlimb phase difference Φ is an order parameter quantifying the spatial-temporal organization of 2 rhythmic subsystems. Dynamical modeling and experimental analyses indicate that an intentional parameter Φψ (intended coordination mode, Φ?=?0° or Φ?=?180°) and 2 control parameters ωc (coupled frequency) and Δω (difference between uncoupled eigenfrequencies) affect Φ. An experiment was conducted on 1:1 frequency locking in which Φψ, ωc, and Δω were manipulated using a paradigm in which a person swings hand-held pendulums. As Δω deviated from 0, the observed Φ deviated from the Φψ, indicating a displacement in the Φ attractor point. The displacements were exaggerated by increasing ωc. The displacements were coordinated with a decrease in the stability of Φ and with higher harmonics in power spectrum of Φ. Implications of the results for modeling interlimb coordination are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of Interlimb Movement Synchrony in the Rat Fetus.

In the fetal rat, interlimb synchrony is a prominent form of temporally organized spontaneous motor activity in which movement of different limbs occurs at nearly the same instant. In the present study, synchrony profiles were created for different pairwise combinations of limbs over the last 5 days of gestation. Observed rates of synchrony differentiated from randomized time series from Gestational Day 19 to Day 21 (E19-E21), with forelimb synchrony emerging earlier than that of other limb pairs. Synchrony profiles were elevated at the shortest intervals between successive limb movements, indicating that movements became more tightly coupled toward the end of gestation. Interlimb synchrony appears to be a robust method of quantifying fetal movement and may prove useful as a tool for assessing prenatal nervous system functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensorimotor state of the contralateral leg affects ipsilateral muscle coordination of pedaling

The objective of this study was to determine if independent central pattern generating elements controlling the legs in bipedal and unipedal locomotion is a viable theory for locomotor propulsion in humans. Coordinative coupling of the limbs could then be accomplished through mechanical interactions and ipsilateral feedback control rather than through central interlimb neural pathways. Pedaling was chosen as the locomotor task to study because interlimb mechanics can be significantly altered, as pedaling can be executed with the use of either one leg or two legs (cf. walking) and because the load on the limb can be well-controlled. Subjects pedaled a modified bicycle ergometer in a two-legged (bilateral) and a one-legged (unilateral) pedaling condition. The loading on the leg during unilateral pedaling was designed to be identical to the loading experienced by the leg during bilateral pedaling. This loading was achieved by having a trained human "motor" pedal along with the subject and exert on the opposite crank the torque that the subject's contralateral leg generated in bilateral pedaling. The human "motor" was successful at reproducing each subject's one-leg crank torque. The shape of the motor's torque trajectory was similar to that of subjects, and the amount of work done during extension and flexion was not significantly different. Thus the same muscle coordination pattern would allow subjects to pedal successfully in both the bilateral and unilateral conditions, and the afferent signals from the pedaling leg could be the same for both conditions. Although the overall work done by each leg did not change, an 86% decrease in retarding (negative) crank torque during limb flexion was measured in all 11 subjects during the unilateral condition. This corresponded to an increase in integrated electromyography of tibialis anterior (70%), rectus femoris (43%), and biceps femoris (59%) during flexion. Even given visual torque feedback in the unilateral condition, subjects still showed a 33% decrease in negative torque during flexion. These results are consistent with the existence of an inhibitory pathway from elements controlling extension onto contralateral flexion elements, with the pathway operating during two-legged pedaling but not during one-legged pedaling, in which case flexor activity increases. However, this centrally mediated coupling can be overcome with practice, as the human "motor" was able to effectively match the bilateral crank torque after a longer practice regimen. We conclude that the sensorimotor control of a unipedal task is affected by interlimb neural pathways. Thus a task performed unilaterally is not performed with the same muscle coordination utilized in a bipedal condition, even if such coordination would be equally effective in the execution of the unilateral task.     

Manipulating symmetry in the coordination dynamics of human movement.

J. A. S. Kelso and J. J. Jeka (see record 1992-41720-001) demonstrated that symmetry is a useful conceptual tool to distinguish the coordination between components with similar vs different anatomical properties. The present experiments studied human arm–leg patterns to test whether their coordinative asymmetry was changed by manipulating the inertial properties of a single limb. The results showed that (1) consistent with model predictions, adding weight to the arm or the leg minimized or enhanced coordinative asymmetry, respectively and (2) the response to a perturbation slowed as movement frequency increased but in a fashion that reflected the underlying coordinative asymmetry. The observed coordinative effects suggest the influence of neural phase relationships and emphasize that symmetry plays an important role in understanding coordination in systems in which control cannot be traced unequivocally to a single end-effector or a neurophysiological substrate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intentional switching between behavioral patterns of homologous and nonhomologous effector combinations.

Intentional switching between preferred coordination modes (Experiment 1) and between isofrequency and multifrequency conditions (Experiments 2 and 3) was compared across different effector combinations. Experiment 1 showed that homologous limbs switched faster toward the in-phase and anti-phase mode than nonhomologous limbs, supporting their distinct degree of coordinative stability during 1:1 synchronization. Experiments 2 and 3 revealed that switching time between isofrequency and multifrequency conditions depended on the attractiveness of both coordination dynamics associated with the combination of segments involved. These results are consistent with the unique prediction derived from dynamic pattern approach in which the differential stability of the coordination modes determines the switching time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)