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Results for “interlimb coordination”

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PubMed2006

Rhythmic coordination of hand and foot in children with Developmental Coordination Disorder.

BACKGROUND: Children with Developmental Coordination Disorder (DCD) have difficulties producing stable rhythmic bimanual coordination patterns in comparison with age-related peers. Rhythmic coordination of non-homologous limbs (e.g. hand and foot) is even more difficult to perform because of mechanical differences between the limbs. The aim of the present study is to investigate the stability of hand-foot coordination patterns of children with DCD. METHODS: Ten children with DCD (mean age 7.0 years, SD 1.1 years) and 16 control children (mean age 7.4 years, SD 1.3 years) participated in the study. They were asked to perform in-phase or anti-phase tapping movements in three different interlimb coordination combinations: (1) hand-hand (homologous), (2) hand-foot same body side (ipsilateral), and (3) hand-foot different body side (contralateral). Coordination stability was measured by the variability of the relative phase between the limbs under a 'steady state' (preferred) frequency condition, and by the critical frequency (i.e. the point at which loss of pattern stability was observed) in a condition in which the movement frequency was 'scaled' up (only anti-phase tapping). RESULTS: Coordination patterns of children in the DCD group were less stable in all three limb combinations compared with controls. Further, hand-foot coordination patterns were less stable than hand-hand coordination patterns. With regard to hand-foot coordination, ipsilateral patterns were equally stable compared with contralateral patterns in the in-phase task, but less stable in the anti-phase task. No differential effects were found between the DCD and control groups across the different limb combinations, except for steady-state anti-phase coordination in the ipsilateral limb condition. This effect was due to a relatively good performance of the control children in this condition in comparison with the other limb combination conditions. CONCLUSIONS: Children with DCD have difficulties producing stable rhythmic hand-foot coordination patterns compared with control children.

Child↗

PubMed1996

Locomotor capacities after complete and partial lesions of the spinal cord.

This paper first reviews some of the observations made on the locomotor capabilities of several animal species with a special emphasis on cats and including primates and man after complete spinal lesions. We show that animals can perform well-coordinated walking movements of the hindlimbs when they are placed on a treadmill belt and this locomotion is also adaptable to speed and perturbations. Cats with partial spinal lesions of the ventral and ventrolateral parts of the cord can perform voluntary quadrupedal locomotion overground or on the treadmill albeit with deficits in weight support and interlimb coordination. We also show that some drugs such as clonidine (an alpha-2 noradrenergic agonist) can be used to trigger locomotion in early-spinal cats and discuss the effects of various neurotransmitter systems on the expression of the locomotor pattern in both complete and partial spinal cats. It is concluded that a pharmacological approach could be used, in combination with other approaches, such as locomotor training and functional electrical stimulation, to improve locomotor functions after spinal cord injuries in humans.

Animals↗

PubMed2003

Classification of dynamics of a model of motor coordination and comparison with Parkinson's disease data.

In our recent reports motor coordination of human lower limbs has been investigated during pedaling a special kind of ergometer which allows its left and right pedals to rotate independently. In particular, relative phase between left and right rotational-velocity waveforms of the pedals and their amplitude modulation have been analyzed for patients with Parkinson's disease (PD). Several patients showed peculiar interlimb coordination different from the regular anti-phase pattern of normal subjects. We have reported that these disordered patterns could be classified into four groups. Moreover, it has been demonstrated that a mathematical model could reproduce most of the disordered patterns. Such a model includes a schematization of the central pattern generator with two identical half-centers mutually coupled and two tonic control signals from higher motor centers, each of which inputs to one of the half-centers. Depending on the intensities of the tonic signals and on the differences between them, the model could generate a range of dynamics comparable to the clinically observed disordered patterns. In this paper, we explore the dynamics of the model by varying the intensities of the tonic signals in the model. Using the same method used for classifying the clinical data, the dynamics of the model are classified into several groups. The classified groups for the simulated data are compared with those for the clinical data to look at qualitative correspondence. Our systematic exploration of the model's dynamics in a wide range of the parameter space has revealed global organization of the bifurcations including Hopf bifurcations and cascades of period-doubling bifurcations among others, suggesting that the bifurcations, induced by instability of stable dynamics of the human motor control system, are responsible for the emergence of the disordered coordination in PD patients.

Cluster Analysis↗

PubMed2001

Coordination of upper and lower limb segments: deficits on the ipsilesional side after unilateral stroke.

Coordination of the ipsilateral limbs was studied in unilateral stroke patients and a control group of healthy age-matched controls. Cyclical single-limb movements of the forearm and lower leg as well as their coordination, with the segments moving either in the same (isodirectional) or in different directions (nonisodirectional), were investigated under normal vision and blindfolded conditions. Findings revealed that stroke patients experienced difficulties with coordination of the limb segments on the ipsilesional side and this effect was more pronounced during nonisodirectional than during isodirectional coordination. In addition, cycle durations were larger and movement amplitudes shorter in stroke patients as compared to controls. Overall, the present findings clearly demonstrated motor control deficits in stroke patients on the so-called "unaffected side." The availability of normal vision did not alleviate these deficits. Therefore, the more general implication of the present findings appears to be that interlimb coordination is a complex function, requiring the integrity of both hemispheres. Comparison of the left- and right-hemispheric stroke groups revealed that patients with a left-hemisphere lesion tended to be more variable in performing the more difficult nonisodirectional pattern than patients with a right-hemisphere lesion. This possibly hints at a more pronounced involvement of the left hemisphere in the organization of ipsilateral coordination. The spatiotemporal features of movement (cycle duration, amplitude), however, did not differ between both stroke groups.

Adult↗

PubMed1987

Neural control of limb coordination. I. Comparison of hatching and walking motor output patterns in normal and deafferented chicks.

Previous work has shown that the neural circuits underlying the leg movements of walking and hatching coexist in post-hatching chicks (Bekoff and Kauer, 1984). In the present study, quantitative analysis of leg EMGs shows that there are some similarities, but also significant differences, in the motor output patterns of walking and hatching. This study examines the effect of removing sensory feedback from the legs on the production of the distinctive leg motor patterns. The temporal characteristics and interlimb coordination of hatching and walking are little affected. However, major changes in intralimb motor output patterns are seen when compared to records from normal chicks. These changes fall into one of 2 categories. Some parameters show similar changes in both behaviors after deafferentation (e.g., increases in flexor burst durations and cycle period). This suggests that certain features of sensory input from the legs normally modulate the hatching and walking pattern-generating circuitry in similar ways. Other parameters show convergence. That is, these aspects of the 2 intralimb motor patterns become more similar to each other after removal of sensory input. This is consistent with the hypothesis that some feature of sensory input from the legs normally modulates one set of multiuse intralimb circuitry to produce different output patterns. In general, the walking pattern becomes more like hatching after deafferentation, rather than the reverse, which suggests that the hatching pattern is a more basic one. The maintenance of some residual differences in intralimb motor patterns after leg deafferentation suggests that other sources of modulation must also be involved, or that there are some additional elements of circuitry that are called into play during the normal production of walking and hatching.

Animals↗

PubMed2005

Unraveling interlimb interactions underlying bimanual coordination.

Three sources of interlimb interactions have been postulated to underlie the stability characteristics of bimanual coordination but have never been evaluated in conjunction: integrated timing of feedforward control signals, phase entrainment by contralateral afference, and timing corrections based on the perceived error of relative phase. In this study, the relative contributions of these interactions were discerned through systematic comparisons of five tasks involving rhythmic flexion-extension movements about the wrist, performed bimanually (in-phase and antiphase coordination) or unimanually with or without comparable passive movements of the contralateral hand. The main findings were the following. 1) Contralateral passive movements during unimanual active movements induced phase entrainment to interlimb phasing of either 0 degrees (in-phase) or 180 degrees (antiphase). 2) Entrainment strength increased with the passive movements' amplitude, but was similar for in-phase and antiphase movements. 3) Coordination of unimanual active movements with passive movements of the contralateral hand (kinesthetic tracking) was characterized by similar bilateral EMG activity as observed in active bimanual coordination. 4) During kinesthetic tracking the timing of the movements of the active hand was modulated by afference-based error corrections, which were more pronounced during in-phase coordination. 5) Indications of in-phase coordination being more stable than antiphase coordination were most prominent during active bimanual coordination and marginal during kinesthetic tracking. Together the results indicated that phase entrainment by contralateral afference contributed equally to the stability of in-phase and antiphase coordination, and that differential stability of these patterns depended predominantly on integrated timing of feedforward signals, with only a minor role for afference-based error corrections.

Adolescent↗

PubMedDate not supplied

Prenatal methylazoxymethanol exposure alters evoked responses in fetal rats.

Although there is considerable interest in identifying methods to detect central nervous system impairment early in development, few behavioral assessment tools are available for detecting CNS deficits in the fetus. In the present study, methylazoxymethanol [MAM; Midwest Research Institute, (MRI)] was used to induce deficits in CNS development in fetal rats to assess effects on coordinated fetal behavior. Fetuses were exposed by administering MAM to pregnant rats on E17 of gestation via intraperitoneal injection and then were prepared for behavioral testing 3 days later on E20. After externalization from the uterus into a warm saline bath, fetal subjects received either an intraoral infusion of lemon extract to evoke a facial wiping response or were presented with an artificial nipple to evoke an oral grasping response. Interlimb coordination and paw-face contact during facial wiping were disrupted in MAM-exposed fetuses. Similarly, MAM exposure diminished the ability of fetuses to grasp or maintain oral contact with the artificial nipple. Although clear disruptions of movement coordination were seen in the MAM-treated subjects, there were no significant differences from saline controls in weight or anatomical measures. Together, these findings suggest that behavioral assessments of fetal motor coordination may be useful in identifying neural insult during prenatal development.

Analysis of Variance↗

PubMed1976

Kinematics of locomotion by cats with a single hindlimb deafferented.

1. Cinematographic measurements were made of stepping by cats on a motor-driven treadmill, both normally and 2-3 wk after deafferentation of the LH (left hind) limb. 2. After surgery, rhythmic cycling of the LH limb was blurred whether the leg was dragged, as by some cats, or if it was lifted from the surface, as by others. 3. Interlimb coordination was also blurred with respect to normal, although distinct rhythms were still seen. The RH (right hind) limb descended prematurely and, in the walk, had a prolonged stance phase. The interval between touchdowns of hind- and forelimb on the left side no longer equaled that interval on the right side. 4. As is true for a normal cat, if the LH-deafferented animal stumbled, relatively normal single and interlimb cyclings were regained after several strides. 5. By kinematic analysis, force deficits were found in the deafferented LH limb both during the stance, when extensors should be most active, and the swing, when the limb failed to attain a normal position above the surface of the belt. Weight bearing by the LF (left fore) limb was altered in some animals. 6. At high speed, mean LH stance duration failed to decrease in the normal fashion. Inter-limb timings were reset to greater extent than in low-speed walking, as if the LH limb was being used only minimally. 7. It was concluded that both rhythm and force were impaired in the deafferented limb and also in the three intact limbs, whose weight bearing had to compensate for LH weakness. The changed mechanical demands after surgery were probably met by interactions between the remaining afferent input and central pattern generators so as to secure fairly effective and expedient locomotion.

Afferent Pathways↗

PubMed1999

The identification of coordination constraints across planes of motion.

Two dominant coordination constraints have been identified during isofrequency conditions in previous work: the egocentric constraint, i.e., simultaneous activation of homologous muscle groups, and the allocentric constraint, i.e., moving the segments in the same direction in extrinsic space. To verify their generalization, bimanual drawing movements were performed in different planes of motion (transverse, frontal, sagittal, frontal-transverse) according to the in-phase and anti-phase mode along the X- and Y-axes. Convergent findings were obtained across the transverse, frontal, and frontal-transverse planes. The in-phase mode along both axes was performed most accurately/consistently, whereas the anti-phase mode resulted in a deterioration of the coordination pattern and this effect was most pronounced when the latter mode was introduced with respect to both dimensions. For sagittal plane motions, the in-phase mode was again superior but the second most optimal configuration was the anti-phase mode along both axes. This finding was hypothesized to result from the familiarity with the pattern since it resembles cycling behavior. It illustrates how cognitive mapping is superimposed onto the dynamics of interlimb coordination. Overall, these results support the presence of both the egocentric and allocentric constraint during bimanual movement production.

Humans↗

PubMed1987

Two-muscle coordination versus natural treadmill locomotion.

When a single-muscle learned behavior was superimposed upon natural human treadmill locomotion, in previous work, it operated as a self-contained behavioral unit. The new behavior altered some features, however, of ongoing stepping patterns. These findings prompted broader consideration of how individual muscle actions combine to form large, patterned ensembles. Accordingly, the present experiment constructed a larger, double-muscle learned behavior to see if it would compete with natural treadmill locomotion or combine with it harmoniously. A demanding requirement was made for in-phase bilateral EMG and contraction by rectus femoris (RF), in opposition to its natural out-of-phase interlimb pattern. EMG bursts were controlled, through computer-assisted operant conditioning, by a flash shortly after left heel strike. The new, double ensemble was conditioned rapidly, within 1-6 days, for all four adults. Harmonious stepping continued, for the most part, with little alteration in step cycle timings. Leg positioning was modified appreciably, however, pointing to complex neural mechanisms. The evidence argued that operant conditioning can construct fine-grained behaviors and also participate powerfully across the full range of single- and interlimb coordination.

Adult↗

PubMed2005

The co-ordination of bimanual rapid aiming movements following stroke.

OBJECTIVE: To determine the role of anticipatory and movement control processes for the coordination of bimanual target aiming in individuals post stroke. SUBJECTS: Thirty adults with chronic stroke and 30 individuals without stroke history. DESIGN: A two-group (stroke, control) by two-aiming type (unimanual, bimanual) by two-limb (paretic, nonparetic; left, right for controls) design with repeated measures on the last two factors. OUTCOME MEASURES: Kinematic analyses of performance and psychometric measures of reaction time, movement time, peak resultant velocity, time to and after peak resultant velocity and interlimb timing for movement initiation and target impact. RESULTS: Compared with unimanual aiming, the nonparetic limb exhibited a prolonged movement time in the bimanual condition; the locus for prolongation was primarily in the deceleration phase. This adaptive response allowed for a nearly simultaneous (both limbs) target impact in 81% of trials. Compared with the unimanual condition, the nonparetic limb exhibited a lower peak velocity (10%) in the bimanual condition. Conversely, compared with the unimanual condition, the paretic limb exhibited a higher peak velocity (4%) in the bimanual condition. This disociation between limb and condition was observed for the stroke group but not the control group. CONCLUSIONS: The interlimb coordination that emerged for the stroke group revealed a complex and asymmetric contribution from each limb mediated through anticipatory and motor control processes. We suggest that this coordination may be harnessed for future bimanual intervention approaches to rehabilitation of upper limb function after stroke.

Adult↗

PubMed2003

Bimanual coordination: constraints imposed by the relative timing of homologous muscle activation.

It has often been supposed that patterns of rhythmic bimanual coordination in which homologous muscles are engaged simultaneously, are performed in a more stable manner than those in which the same muscles are activated in an alternating fashion. In order to assess the efficacy of this constraint, the present study investigated the effect of forearm posture (prone or supine) on bimanual abduction-adduction movements of the wrist in isodirectional and non-isodirectional modes of coordination. Irrespective of forearm posture, non-isodirectional coordination was observed to be more stable than isodirectional coordination. In the latter condition, there was a more severe deterioration of coordination accuracy/stability as a function of cycling frequency than in the former condition. With elevations in cycling frequency, the performers recruited extra mechanical degrees of freedom, principally via flexion-extension of the wrist, which gave rise to increasing motion in the vertical plane. The increases in movement amplitude in the vertical plane were accompanied by decreasing amplitude in the horizontal plane. In agreement with previous studies, the present findings confirm that the relative timing of homologous muscle activation acts as a principal constraint upon the stability of interlimb coordination. Furthermore, it is argued that the use of manipulations of limb posture to investigate the role of other classes of constraint (e.g. perceptual) should be approached with caution because such manipulations affect the mapping between muscle activation patterns, movement dynamics and kinematics.

Adult↗

PubMed1990

A kinematic analysis of hindlimb motility in 9- and 10-day-old chick embryos.

Although chick embryonic leg movements appear jerky and disorganized, the underlying motor patterns are coordinated. This apparent conflict in results was investigated using kinematic analyses to provide detailed quantitative descriptions of leg movements during spontaneous motility in 9- and 10-day-old chick embryos. In many respects, hip, knee, and ankle movements were highly variable. There was variation in movement durations and in the number of leg joints that participated in a given movement. Motion could begin with either flexion or extension. Furthermore, the limb could return to its rest position between movements or move continuously to produce sequences of variable lengths. Patterns of interlimb coordination included alternating, synchronous and independent movements of the legs. We propose that these variable features account for the uncoordinated appearance of embryonic leg movements. In addition to variable features, however, some consistent characteristics were identified. For example, when more than one joint was active, activity typically began and ended synchronously. Furthermore, all active joints generally extended or flexed together and movements were symmetrical. These data are consistent with previous EMG results. Therefore, despite the variability in some parameters that results in the perception that embryonic leg movements are random and uncoordinated, our kinematic analyses show that an organized pattern of interjoint coordination is a prominent feature. This basic pattern shows some similarities to, but is less complex than, kinematic patterns found during a variety of posthatching behaviors.

Animals↗

PubMed2005

Limb movements during embryonic development in the chick: evidence for a continuum in limb motor control antecedent to locomotion.

New imaging technologies are revealing ever-greater details of motor behavior in fetuses for clinical diagnosis and treatment. Understanding the form, mechanisms, and significance of fetal behavior will maximize imaging applications. The chick is readily available for experimentation throughout embryogenesis, making it an excellent model for this purpose. Yet in 40 yr since Hamburger and colleagues described chick embryonic behavior, we have not determined if motility belongs to a developmental continuum fundamental to posthatching behavior. This study examined kinematics and synchronized electromyography (EMG) during spontaneous limb movements in chicks at four time points between embryonic days (E) 9-18. We report that coordinated kinematic and/or EMG patterns were expressed at each time point. Variability observed in knee and ankle excursions at E15-E18 sorted into distinct in-phase and out-of-phase patterns. EMG patterns did not directly account for out-of-phase patterns, indicating study of movement biomechanics will be critical to fully understand motor control in the embryo. We also provide the first descriptions of 2- to 10-Hz limb movements emerging E15-E18 and a shift from in-phase to out-of-phase interlimb coordination E9-E18. Our findings revealed that coordinated limb movements persist across development and suggest they belong to a developmental continuum for locomotion. Limb patterns were consistent with the half center model for a locomotor pattern generator. Achievement of these patterns by E9 may thus indicate the embryo has completed a critical phase beyond which developmental progression may be less vulnerable to experimental perturbations or prenatal events.

Age Factors↗

PubMed1997

Glycinergic inhibition contributes to the generation of rostral scratch motor patterns in the turtle spinal cord.

Cutaneous stimulation within the rostral scratch receptive field in a low spinal-immobilized turtle elicits a fictive rostral scratch reflex characterized by robust rhythmic motor output from ipsilateral hindlimb muscle nerves and weaker, alternating motor discharge in contralateral nerves. Simultaneous bilateral stimulation elicits bilateral rostral scratch motor patterns in which activity on the right and left sides alternates. We investigated the role of glycinergic inhibition in the generation and coordination of fictive rostral scratch motor patterns. Glycine (2 or 5 mM) and strychnine (5-50 microM), a glycine antagonist, were superfused over the anterior spinal hindlimb enlargement while fictive rostral scratch motor output was recorded bilaterally from hindlimb muscle nerves in the form of electroneurograms (ENGs). Although glycine reduced rostral scratch burst frequencies, strychnine tended to increase burst frequency. Strychnine also changed the shape of hip flexor ENG bursts, resulting in more abrupt burst onsets, indicating an earlier recruitment of motor neurons with large ENG spikes. During bilateral stimulation, strychnine increased the variability of interlimb phase values (left vs right hip flexor bursts) but did not abolish right-left alternation. These results indicate that glycinergic neurons in or near the anterior hindlimb enlargement contribute to the overall timing of the rostral scratch rhythm and to the recruitment timing of individual hip flexor motor neurons within each scratch burst. Our data also indicate that glycinergic mechanisms contribute to, but are not critically important for, maintaining an alternating interlimb coordination during bilateral scratch motor patterns.

Animals↗

PubMed1998

A mathematical model of adaptive behavior in quadruped locomotion.

Locomotion involves repetitive movements and is often executed unconsciously and automatically. In order to achieve smooth locomotion, the coordination of the rhythms of all physical parts is important. Neurophysiological studies have related that basic rhythms are produced in the spinal network called, the central pattern generator (CPG), where some neural oscillators interact to self-organize coordinated rhythms. We present a model of the adaptation of locomotion patterns to a variable environment, and attempt to elucidate how the dynamics of locomotion pattern generation are adjusted by the environmental changes. Recent experimental results indicate that decerebrate cats have the ability to learn new gait patterns in a changed environment. In those experiments, a decerebrate cat was set on a treadmill consisting of three moving belts. This treadmill provides a periodic perturbation to each limb through variation of the speed of each belt. When the belt for the left forelimb is quickened, the decerebrate cat initially loses interlimb coordination and stability, but gradually recovers them and finally walks with a new gait. Based on the above biological facts, we propose a CPG model whose rhythmic pattern adapts to periodic perturbation from the variable environment. First, we design the oscillator interactions to generate a desired rhythmic pattern. In our model, oscillator interactions are regarded as the forces that generate the desired motion pattern. If the desired pattern has already been realized, then the interactions are equal to zero. However, this rhythmic pattern is not reproducible when there is an environmental change. Also, if we do not adjust the rhythmic dynamics, the oscillator interactions will not be zero. Therefore, in our adaptation rule, we adjust the memorized rhythmic pattern so as to minimize the oscillator interactions. This rule can describe the adaptive behavior of decerebrate cats well. Finally, we propose a mathematical framework of an adaptation in rhythmic motion. Our framework consists of three types of dynamics: environmental, rhythmic motion, and adaptation dynamics. We conclude that the time scale of adaptation dynamics should be much larger than that of rhythmic motion dynamics, and the repetition of rhythmic motions in a stable environment is important for the convergence of adaptation.

Adaptation, Physiological↗

PubMed2002

Coordination and movement pathology: models of structure and function.

Here we consider the role of abstract models in advancing our understanding of movement pathology. Models of movement coordination and control provide the frameworks necessary for the design and interpretation of studies of acquired and developmental disorders. These models do not however provide the resolution necessary to reveal the nature of the functional impairments that characterise specific movement pathologies. In addition, they do not provide a mapping between the structural bases of various pathologies and the associated disorders of movement. Current and prospective approaches to the study and treatment of movement disorders are discussed. It is argued that the appreciation of structure-function relationships, to which these approaches give rise, represents a challenge to current models of interlimb coordination, and a stimulus for their continued development.

Humans↗

PubMed2004

Effector dynamics of rhythmic wrist activity and its implications for (modeling) bimanual coordination.

To examine the role of the effector dynamics of the wrist in the production of rhythmic motor activity, we estimated the phase shifts between the EMG and the task-related output for a rhythmic isometric torque production task and an oscillatory movement, and found a substantial difference (45-52 degrees) between the two. For both tasks, the relation between EMG and task-related output (torque or displacement) was adequately reproduced with a physiologically motivated musculoskeletal model. The model simulations demonstrated the importance of the contribution of passive structures to the overall dynamics and provided an account for the observed phase shifts in the dynamic task. Additional simulations of the musculoskeletal model with added load suggested that particular changes in the phase relation between EMG and movement may follow largely from the intrinsic muscle dynamics, rather than being the result of adaptations in the neural control of joint stiffness. The implications of these results are discussed in relation to (models of) interlimb coordination in rhythmic tasks.

Electromyography↗