In-phase Pattern Research Articles

Learning and transfer in motor-respiratory coordination

Motor-respiratory coordination occurs naturally during exercise, but the number of coordination patterns performed between movement and breathing is limited. We investigated whether participants could acquire novel ratios (either 5:2 or 5:3). To examine complex temporal relationships between movement and breathing, we used lagged return plots that were produced by graphing relative phase against relative phase after a time delay. By the end of practice, participants performed 5:2 consistently and performed 5:3 using more stable ratios (3:2 and 2:1). Lagged return plots revealed that 5:3 learners harnessed the stable inphase and antiphase patterns to stabilize the required ratio. That strategy resulted in the performance of smaller-integer ratios in the production of 5:3 but not 5:2. Despite those differences, there was positive transfer to unpracticed ratios that was similar in both learning conditions. The time series analysis of lagged return plots revealed differences in ratio performance at transfer. Ratios whose component frequencies were farther apart, like 7:2, were performed consistently, while ratios whose component frequencies were more similar, like 5:4, elicited attraction to inphase and antiphase. The implication is that participants can combine more stable chunks of rhythmic behavior to produce more complex ratios.

The effect of an on-body assistive device on transverse plane trunk coordination during a load carriage task

Load carriage is a physically demanding task that is often required of employees in many different occupations. The Mover's Assistive Device (MAD) is an on-body ergonomic assistive device designed to help professional movers transfer boxes during two techniques of hand-held load carriage: anterior carriage and posterior carriage. The purpose of this study was to examine the intersegment coordination between the trunk and pelvis as well as the trunk and box, since coordination may be a mechanism to reduce the amount of stress exerted on the back during load carriage. Thirteen males completed a hand-held load carriage task in a laboratory setting using two popular techniques employed by professional movers (anterior/posterior), with and without the assistance of the Mover's Assistive Device (MAD); resulting in a total of four conditions. Triads of retro-reflective markers tracked the angular positions of the trunk, pelvis and the load being carried. Intersegment coordination between the trunk-pelvis and the box-trunk were measured using continuous relative phase angles in the transverse plane of motion. No trunk coordination differences were observed across carrying techniques (anterior/posterior); however, under all conditions users walked with a near in-phase coordination pattern, which is believed to help reduce the risk of injury. MAD use resulted in decreased perceived discomfort and more in-phase coordination between the trunk-pelvis, which may help reduce injury risk when carrying loads either anteriorly or posteriorly.

Functional specialization within the supplementary motor area: A fNIRS study of bimanual coordination

Bimanual movements can be performed by flexing and extending the target effectors (e.g., hand muscles) in unison, or by flexing units on one side in unison with extension of the same units on the opposite side. The former movement patterns are generally referred to as in-phase or parallel, whereas the latter patterns are often termed anti-phase movements. It is well known that anti-phase patterns are unstable and tend to spontaneously transition to in-phase movements at higher repetition rates, but the mechanisms and brain regions involved are not fully understood. In the current study, we utilized functional near-infrared spectroscopy (fNIRS) to evaluate whether anterior/posterior subdivisions of the supplementary motor complex (SMA) have distinct functional roles in maintaining in-phase and anti-phase movement patterns. Twelve healthy adult participants completed a bimanual coordination task comprised of anti-phase and in-phase trials as 24-channel fNIRS data was recorded from dorsal-medial motor areas. We examined the relative concentrations of oxygenated and deoxygenated hemoglobin in the channels that were located over the anterior SMA (e.g., pre-SMA) and the SMA proper. Our most interesting results indicated that oxygenated hemoglobin responses were greater in the anterior SMA during performance of anti-phase compared to in-phase movements. In the SMA proper, oxygenated hemoglobin responses did not differ between the two movement patterns. These data suggest that the anterior SMA is critical to programming and maintaining the less stable anti-phase movement patterns, and support the conceptual framework of an anterior-directed gradient of progressively more complex functionality in the SMA.

Cooperating with your romantic partner

Romantic partners’ emotions become coordinated in various ways and this may have implications for well-being (Butler (2011) Temporal interpersonal emotion systems: The “TIES” that form relationships. Personality and Social Psychology Review, 15, 367–393.). The present study uses a community sample of 44 committed heterosexual couples to examine whether cooperation, a generally beneficial relational process, is associated with emotional coordination and whether the pattern differs when men’s emotions are coordinated with their female partners’ prior emotions or vice versa. Using behavioral observations of cooperation and second-to-second measures of emotional experience during a face-to-face conversation, men showed the most positive emotional experience at high levels of mutual cooperation. As predicted, cooperation was associated with different coordination patterns for men and women, with high mutual cooperation predicting an inphase pattern for men (emotions changing in unison with their partners) and an antiphase pattern for women (emotions changing in opposite directions from their partners). Our results suggest that men and women may experience cooperation differently, despite engaging in similar behaviors.

Two-beam coherent addition using the stochastic parallel gradient descent algorithm

The coherent addition of multiple beams is one of the great challenges in terms of large-scale lasers. Implementing the capability to generate ultra-high-focus power intensity on the focal plane places stringent requirements on the control of each beam’s pointing and intra-beam phasing. The random beam-to-beam phase jumps, mainly induced by the catoptric elements’ rapid vibration, should be eliminated to realize phase locking. A two-way laser beam’s coherent combination test bed is designed to test the capabilities of phase-locking system. The results show that the closed-loop feedback system achieved a high contrast of the in-phase intensity pattern at the receiving plane after correcting for piston and tip/tilt errors between two adjacent laser beams by the stochastic parallel gradient descent algorithm.

Strong anticipation: complexity matching in interpersonal coordination

A subtle coordination occurs within complex systems, between multiple nested sub-systems. This intra-system coordination can be detected by the presence of 1/f fluctuations produced by the system. But coordination can occur also between systems. Interpersonal coordination has been studied from a local point of view until now, focusing on macroscopic interactions. But the recent concept of strong anticipation introduced by Dubois (Lect Notes Comput Sci 2684:110-132, 2003) suggests that interactions could occur on multiple levels between complex systems. The hypothesis is that time series in interpersonal synchronization present a matching of the complexity index (fractal exponent). Moreover, it is argued that this matching is not a consequence of short-term adaptations but reveals a global coordination between participants. Eleven pairs of participants oscillated a hand-held pendulum in the in-phase pattern for 11 min, in three conditions where the coupling strength was manipulated by the perceptual feedbacks. The results show a high correlation between fractal exponents irrespective of the coupling strength, and a very low percentage of local cross-correlations between time series appear at lag 0 and lag 1. These results suggest that interpersonal coordination, and more globally synchronization of participants with natural environments, is based on non-local time scales.

Constraints on competitive performance of attacker–defender dyads in team sports

Previous research on coordination dynamics of 1 vs. 1 sub-phases in team sports has reported stable emergent patterns of coordination in the displacement trajectories of attackers and defenders. The aim of this study was to use attacker–defender interactions in competitive team match-play to investigate how the locations of the goal and ball constrain the pattern-forming dynamics of attacker–defender dyadic systems. Ten high-level futsal matches were filmed and 13 goal sequences selected for analysis. Displacements of the players and the ball were filmed and digitized from 52 attacker–defender dyadic system interactions. Results showed that, although attackers and defenders exhibited similar angular orientations to the goal, the latter always remained closer to the goal than attackers. Observations revealed that in-phase patterns of coordination emerged from changes to both the distances and angles of attackers and defenders to the goal. Attackers always remained closer to the ball than defenders, while the latter exhibited a lower angle to the ball than attackers. A pattern of in-phase coordination modes emerged between the attackers and defenders' distances and angles to the ball. This study helps us to understand interpersonal interactions in team sports by explaining how attackers and defenders use information about their relative positioning to the goal and the ball to perform successfully.

Effects of gait pattern and arm swing on intergirdle coordination

Mature locomotion in humans is characterized by an anti-phase coordination (moving in opposite directions) between the pelvic and the scapular girdles. This pattern involves a specific relationship between the arm and leg motion is deemed to be most flexible and dynamically efficient. Still, when the arms are involved in another task, like a field player running with a ball in the hands, locomotion is still possible. In order to probe the flexibility of the locomotor synergy, the present study aimed to determine the persistence and the strength of the coordination patterns between the pelvic and scapular girdles when no arm swing was allowed during walking and running.Relative phase, the time difference between the girdle rotations, measured the ongoing inter-girdle coordination of eight healthy participants asked to walk and run with or without arm swing. Results showed that an absence of arm swing led to a change from an anti-phase to in-phase pattern (girdles moving in the same direction) and that an increase in velocity strengthened the adopted pattern. Moreover, the frequency distribution of relative phase for all gait patterns with arm swing proved to be bimodal, indicating that the prevailing anti-phase pattern was always mixed with a noticeable proportion of in-phase coordination. The presence of the in-phase pattern in the easy, natural locomotion with arm swing manifests its persistence and its stability, perhaps pertaining to its prevalence in earlier times in ontogeny or evolution.

Force synchrony enhances the stability of rhythmic multi-joint arm coordination

Although rhythmic coordination has been extensively studied in the literature, questions remain about the correspondence of constraints that have been identified in the related contexts of inter-limb and intra-limb coordination. Here we used a 2-DOF robot arm which allows flexible manipulation of forces to investigate the effect on coordination stability of intra-limb coordination of: (i) the synchrony of force requirements and (ii) the involvement of bi-functional muscles. Ten subjects produced simultaneous rhythmic flexion-extension (FE) and supination-pronation (SP) elbow movements in two coordination patterns: (1) flexion synchronized with supination/extension with pronation (in-phase pattern) and (2) flexion synchronized with pronation/extension with supination (anti-phase pattern). The movements were produced with five different settings of the robot arm: a neutral setting that imposed balanced force requirements, and four other settings that increased the force requirements for one direction in both DOF. When combined with specific coordination patterns, these settings created conditions in which either synchronous or alternate patterns of forcing were necessary to perform the task. Results showed that synchronous tasks were more stable than asynchronous tasks (P<0.05). Within the synchronous tasks, some robot settings were designed to either increase or decrease the use of bi-functional muscles. Although there was no difference for the bi-functional muscle biceps brachii, the coordination was more stable for the condition in which the greatest force requirements corresponded to the mechanical action of the bi-functional pronator teres (P<0.05). In conclusion, force synchrony increases the stability of rhythmic intra-limb coordination, but further research is needed to clarify the role of bi-functional muscles in this effect.

Movement Initiation-Locked Activity of the Anterior Putamen Predicts Future Movement Instability in Periodic Bimanual Movement

In periodic bimanual movements, anti-phase-coordinated patterns often change into in-phase patterns suddenly and involuntarily. Because behavior in the initial period of a sequence of cycles often does not show any obvious errors, it is difficult to predict subsequent movement errors in the later period of the cyclical sequence. Here, we evaluated performance in the later period of the cyclical sequence of bimanual periodic movements using human brain activity measured with functional magnetic resonance imaging as well as using initial movement features. Eighteen subjects performed a 30 s bimanual finger-tapping task. We calculated differences in initiation-locked transient brain activity between antiphase and in-phase tapping conditions. Correlation analysis revealed that the difference in the anterior putamen activity during antiphase compared within-phase tapping conditions was strongly correlated with future instability as measured by the mean absolute deviation of the left-hand intertap interval during antiphase movements relative to in-phase movements (r = 0.81). Among the initial movement features we measured, only the number of taps to establish the antiphase movement pattern exhibited a significant correlation. However, the correlation efficient of 0.60 was not high enough to predict the characteristics of subsequent movement. There was no significant correlation between putamen activity and initial movement features. It is likely that initiating unskilled difficult movements requires increased anterior putamen activity, and this activity increase may facilitate the initiation of movement via the basal ganglia-thalamocortical circuit. Our results suggest that initiation-locked transient activity of the anterior putamen can be used to predict future motor performance.

Effects of movement stability and congruency on the emergence of spontaneous interpersonal coordination

The current project evaluated the relationship between the stability of intrapersonal coordination and the emergence of spontaneous interpersonal coordination. Participants were organized into pairs, and each participant was instructed to produce either an inphase or antiphase pattern of intrapersonal bimanual coordination using two hand-held pendulums, while simultaneously performing an interpersonal puzzle task. At issue was whether the emergence and stability of spontaneous interpersonal rhythmic coordination is influenced by ("Experiment 1") the stability of the intrapersonal coordination patterns produced by co-actors and ("Experiment 2") the congruency of the intrapersonal coordination patterns produced by co-actors. The stability of intrapersonal movement coordination did not affect the emergence of spontaneous interpersonal coordination. The degree of interpersonal coordination observed was similar when both participants in a pair produced either inphase or antiphase patterns of intrapersonal bimanual coordination. Moreover, the congruency of the intrapersonal coordination patterns only slightly affected the emergence of interpersonal coordination, with only marginally lower inphase interpersonal entrainment when participants produced incongruent patterns of intrapersonal coordination (e.g., inphase-antiphase). Interestingly, movement observation and the emergence of interpersonal coordination did not affect the stability of intrapersonal bimanual coordination. The results suggest that interlimb rhythmic bimanual coordination reflects a single intrapersonal perceptual-motor synergy and that these bimanual synergies (not individual limbs) are what become spontaneously entrained interpersonally.

Effect of Coordination Biofeedback on (Re)Learning Preferred Postural Patterns in Post-stroke Patients

After stroke, ankle-hip coordination during stance is characterized by changes in the postural system dynamics, specifically the disappearance of the in-phase pattern and the reduced stability of the anti-phase pattern. This study was conducted to assess the success of a coordination visual biofeedback for the (re)learning of the two preferred patterns, and to explore the effect of this treatment on postural and functional abilities. Twenty four patients were randomly assigned to one of two experimental groups or to a control group. During one month, patients from experimental groups followed a training protocol on the two preferred postural patterns using the biofeedback device. These two groups improved their in-phase coordination after the (re)learning compared with control group, and showed a related improvement of the functional independence measure. Results suggest that (re)learning the in-phase pattern is possible and seems to improve independence in poststroke patients.

Frequency-induced changes in interlimb interactions: Increasing manifestations of closed-loop control

In bimanual coordination, interactions between the limbs result in attraction to in-phase and antiphase coordination. Increasing movement frequency leads to decreasing stability of antiphase coordination, often resulting in a transition to the more stable in-phase pattern. It is unknown, however, how this frequency-induced loss of stability is engendered in terms of the interlimb interactions underwriting bimanual coordination. The present study was conducted to help resolve this issue. Using an established method (based on comparison of various unimanual and bimanual tasks involving both passive and active movements), three sources of interlimb interaction were dissociated: (1) integrated timing of feedforward signals, (2) afference-based correction of relative phase errors, and (3) phase entrainment by contralateral afference. Results indicated that phase entrainment strength remained unaffected by frequency and that the stabilizing effects of error correction and integrated timing decreased with increasing frequency. Their contributions, however, reflected an interesting interplay as frequency increased. For moderate frequencies coordinative stability was predominantly secured by integrated timing processes. However, at high frequencies, the stabilization of the antiphase pattern required combined contributions of both integrated timing and error correction. In sum, increasing frequency was found to induce a shift from predominantly open-loop control to more closed-loop control. The results may be accounted for by means of an internal forward model for sensorimotor integration in which the sensory signals are compared to values predicted on the basis of efference copies.

Distributional Properties of Relative Phase in Bimanual Coordination

Studies of bimanual coordination have typically estimated the stability of coordination patterns through the use of the circular standard deviation of relative phase. The interpretation of this statistic depends upon the assumption of a von Mises distribution. The present study tested this assumption by examining the distributional properties of relative phase in three bimanual coordination patterns. There were significant deviations from the von Mises distribution due to differences in the kurtosis of distributions. The kurtosis depended upon the relative phase pattern performed, with leptokurtic distributions occurring in the in-phase and antiphase patterns and platykurtic distributions occurring in the 30° pattern. Thus, the distributional assumptions needed to validly and reliably use the standard deviation are not necessarily present in relative phase data though they are qualitatively consistent with the landscape properties of the intrinsic dynamics.

Hopf bifurcation and spatio-temporal patterns in delay-coupled van der Pol oscillators

In this paper, the dynamics of a pair of van der Pol oscillators with delayed velocity coupling is studied by taking the time delay as a bifurcation parameter. We first investigate the stability of the zero equilibrium and the existence of Hopf bifurcations induced by delay, and then study the direction and stability of the Hopf bifurcations. Then by using the symmetric bifurcation theory of delay differential equations combined with representation theory of Lie groups, we investigate the spatio-temporal patterns of Hopf bifurcating periodic oscillations. We find that there are different in-phase and anti-phase patterns as the coupling time delay is increased. The analytical theory is supported by numerical simulations, which show good agreement with the theory.

ACL Research Retreat V

ACL Research Retreat V

Do Vision and Audition Influence Bimanual Timing Coordination for In-Phase and Anti-Phase Patterns in a Linear Slide Task?~!2010-03-11~!2010-05-07~!2010-07-13~!

Do Vision and Audition Influence Bimanual Timing Coordination for In-Phase and Anti-Phase Patterns in a Linear Slide Task?~!2010-03-11~!2010-05-07~!2010-07-13~!

Changes in preferred postural patterns following stroke during intentional ankle/hip coordination

We compared the spatio-temporal postural organization between stroke patients and healthy controls in a bipedal standing task where participants had to intentionally produce two specific ankle/hip coordination patterns: in-phase and anti-phase. The pattern to reproduce was visually represented by a ankle–hip Lissajous figure, and a real-time biofeedback displayed the current coordination sur-imposed to the expected coordination. Contrary to the healthy participants who were successful at reproducing the two patterns, stroke patients were unable to produce the in-phase pattern. In addition, when the anti-phase pattern was required, a reduction of stability was observed for the stroke group. The impairment of postural capacities following stroke was thus accompanied by a disappearance of one of the two preferred patterns found in healthy participants, a result that have consequences for understanding the etiology of postural pattern formation and the elaboration of rehabilitation programs.

Stable coherent beam combination by active phasing a mutual injection-locked fiber laser array

We present what we believe to be a new approach for active phasing a mutual injection-locked fiber laser array. The combined advantage of active phasing and mutual injection provides a robust performance in the practical turbulent environment and high tolerance on the requirement on the laser linewidth. A proof-of-concept experiment is performed by active phasing a mutually coupled laser array, and a fringe contrast of more than 79% of the in-phase intensity pattern at the receiving plane is obtained.

Premature infant swallowing: Patterns of tongue-soft palate coordination based upon videofluoroscopy

Coordination between movements of individual tongue points, and between soft palate elevation and tongue movements, were examined in 12 prematurely born infants referred from hospital NICUs for videofluoroscopic swallow study (VFSS) due to poor oral feeding and suspicion of aspiration. Detailed post-evaluation kinematic analysis was conducted by digitizing images of a lateral view of digitally superimposed points on the tongue and soft palate. The primary measure of coordination was continuous relative phase of the time series created by movements of points on the tongue and soft palate over successive frames. Three points on the tongue (anterior, medial, and posterior) were organized around a stable in-phase pattern, with a phase lag that implied an anterior to posterior direction of motion. Coordination between a tongue point and a point on the soft palate during lowering and elevation was close to anti-phase at initiation of the pharyngeal swallow. These findings suggest that anti-phase coordination between tongue and soft palate may reflect the process by which the tongue is timed to pump liquid by moving it into an enclosed space, compressing it, and allowing it to leave by a specific route through the pharynx.