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Results for “interlimb coordination”

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PubMed2002

Kinematic analysis of kicking movements in preterm infants with very low birth weight and full-term infants.

BACKGROUND AND PURPOSE: Study of kicking development provides important information to understand how early spontaneous movements change in infants as they acquire voluntary control. Researchers have investigated the kicking movements of preterm infants; however, the movement patterns that they have described were inconsistent. The purpose of this study, therefore, was to examine the development of kicking movements with kinematic analysis in preterm infants with very low birth weight (VLBW) and full-term infants. SUBJECTS AND METHODS: Twenty-two infants with VLBW who were divided into low gestational age (gestational age of <30 weeks, n=9) and high gestational age (gestational age of >or=30 weeks, n=13) classes and 22 full-term infants were evaluated during kicking movements using 4 synchronized cameras and 3-dimensional kinematic analysis when the infants were 2 and 4 months of corrected age. RESULTS: The infants with VLBW and a high gestational age showed similar kicking movements compared with the full-term infants. In contrast, the infants with VLBW and a low gestational age exhibited a higher kick frequency and a shorter flexion phase at 4 months of corrected age. They also exhibited a higher hip-knee correlation and lower variability in the interlimb coordination pattern at 2 and 4 months of corrected age. DISCUSSION AND CONCLUSION: The findings indicate that infants with VLBW, particularly those with a low gestational age, have age-related differences in movement organization and coordination of kicking compared with full-term infants.

Age Factors↗

PubMed2002

Postural modifications and neuronal excitability changes induced by a short-term serotonin depletion during neonatal development in the rat.

Serotonin (5-HT) plays an important role both in the development and in the recovery of locomotion after spinalization in vertebrates. We investigated the contribution of the serotonergic system to the maturation of the lumbar motoneurons and networks in the neonatal rat. A 5-HT synthesis inhibitor, p-chlorophenylalanine (PCPA), was administered daily from the first postnatal day (P0) onward. This protocol depleted serotonin in the spinal cord within 3-4 d, as demonstrated by immunohistochemistry. PCPA-treated rats exhibited postural changes characterized by lesser flexion at the knee and ankle levels and lesser extension of the hip. Posture was asymmetric, suggesting possible deficits in the interlimb coordination. Intracellular recordings were made at P3-5 from motoneurons innervating different hindlimb muscles, using the in vitro brainstem-spinal cord-nerve-attached preparation. In PCPA-treated rats, the conduction velocity of motoneurons was increased, and their excitability was decreased (because of higher rehobase and input conductance) compared with sham animals. In accordance with postural observations, changes were more pronounced in hip extensor/knee flexor than in ankle extensor motoneurons. The maturation of repetitive firing properties was stopped by PCPA treatment, although PCPA, applied in vitro, had no effect on membrane properties. The spontaneous endogenously generated activity, which is a characteristic of immature networks, was increased in PCPA-treated rats, suggesting that developing lumbar networks are sensitive to 5-HT levels. Serotonin may play a critical role during development in regulating the balance between the excitability of motoneurons and that of interneurons. Interneuronal excitability is crucial for the activity-dependent development of spinal cord networks.

Animals↗

PubMed2004

Relationship between spontaneous kicking and age of walking attainment in preterm infants with very low birth weight and full-term infants.

BACKGROUND AND PURPOSES: Although early kicking differences have been reported for preterm infants without overt cranial sonographic abnormalities, their functional importance remains unclear because no outcomes have been measured. Therefore, the first purpose of this prospective study was to examine the age of walking attainment in preterm infants who had very low birth weight (VLBW) but no overt neurosonographic abnormalities and full-term infants without known impairments or pathology. The second purpose was to examine the relationship between spontaneous kicking and age of walking attainment in these infants. SUBJECTS AND METHODS: Twenty-two preterm infants and 22 full-term infants were examined for kicking movements at 2 and 4 months corrected age and were followed up for age of walking attainment until 18 months corrected age. RESULTS: Survival analysis showed that infants with VLBW attained walking ability at older ages than full-term infants after correction for prematurity. Cox proportional-hazards regression analyses for all infants revealed that a high hip-knee correlation at 2 months corrected age, a high kick frequency at 4 months corrected age, and a short intra-kick pause together with a low variability in interlimb coordination at 2 and 4 months corrected age were all associated with a decreased rate of walking attainment. DISCUSSION AND CONCLUSION: The results indicated that preterm infants who had VLBW but no overt neurosonographic abnormalities had an increased risk of delayed walking attainment compared with full-term infants. Alterations of spontaneous kicking may predict a decreased rate of walking attainment in both preterm and full-term infants.

Age Factors↗

PubMed1995

Bilateral control of hindlimb scratching in the spinal turtle: contralateral spinal circuitry contributes to the normal ipsilateral motor pattern of fictive rostral scratching.

In a spinal turtle, unilateral stimulation in the rostral scratch receptive field elicited rhythmic fictive rostral scratching in ipsilateral hindlimb motor neurons; contralateral hip motor activity was also rhythmic and out-of-phase with ipsilateral hip motor activity. When left and right rostral scratch receptive fields were stimulated simultaneously, bilateral rhythmic fictive rostral scratching was produced; left hindlimb scratching was out-of-phase with right hindlimb scratching. Thus, spinal circuits coordinate interlimb phase during bilateral fictive scratching. We examined the contributions of contralateral spinal circuitry to the normal pattern of right hindlimb fictive rostral scratching by removing the left halves of the D7 segment and the hindlimb enlargement (D8-S2 segments). After left-hemicord removal, stimulation in the right rostral scratch receptive field usually elicited a variation of rostral scratching with rhythmic right hip flexor activity and no right hip extensor activity; thus, right hip flexor rhythm generation does not require left hindlimb enlargement circuitry. Normal right hindlimb rostral scratching with rhythmic alternation between hip flexor and extensor activities was rarely observed; thus, contralateral spinal circuitry contributes to the production of normal ipsilateral fictive rostral scratching. After left-hemicord removal, stimulation in the left rostral scratch receptive field elicited rhythmic right hip extensor activity; thus, contralateral spinal circuitry can generate a hip extensor rhythm during ipsilateral rostral scratch receptive field stimulation. Our observations and those of Berkowitz and Stein (1994a,b) support the concept that an ipsilateral hindlimb's normal rostral scratch motor pattern is generated by a modular central pattern generator that is bilaterally distributed in the spinal cord.

Animals↗

PubMed1994

Phase-entrainment dynamics of visually coupled rhythmic movements.

Do interlimb rhythmic coordinations between individuals exhibit the same relations among the same observable quantities as interlimb rhythmic coordination within an individual? The 1:1 frequency locking between the limbs of two people was investigated using a paradigm in which each person oscillated a hand-held pendulum, achieving and maintaining the mutual entrainment through vision. The intended coordination was antiphase, phi = pi, and the difference between the uncoupled eigen-frequencies, delta omega, was manipulated through differences in the lengths of the two pendulums. The mean phase relation and its variance for visually coupled coordinations differing in delta omega were predicted by an order parameter equation developed by Haken et al. (1985) and Schöner et al. (1986) for the relative phase of correlated movements of limb segments. Specifically, the experiment revealed that: (1) the deviation of phi from pi increased with increasing deviation of delta omega from 0; and (2) fluctuations in phi increased with increasing deviation of delta omega from 0. With deviations of delta omega from 0, new peaks were added at higher harmonics in phi's power spectrum. These results were in agreement with previous research on the stable states of interlimb coordination within a person, mediated by mechanoreceptive rather than photoreceptive mechanisms. Additionally, they were in agreement with previous research on phase transitions in interlimb coordination which have been shown to conform to the same order parameter dynamics whether the coupling be mechanoreceptively or photoreceptively based. It was suggested that phase entrainment in biological movement systems may abide by dynamical principles that are indifferent to the details of the coupling.

Adult↗

PubMed1997

Age Changes in Interlimb Coupling and the Development of Bimanual Coordination.

Changes in interlimb coupling, and their role in the development of bimanual coordination, were studied longitudinally in 6- to 12-month-old infants (N = 6). Infants were observed while they were reaching for simple objects of 2 different sizes. Their use of a uni- versus bimanual strategy for reaching as well as the coupling of their bimanual movements were compared; progress in bimanual coordination of complementary movements was evaluated on 3 different bimanual tasks. The bimanual tasks involved an asymmetrical cooperation between the 2 hands. Although spatiotemporal coupling of bimanual reaching movements did not decrease during the age period studied, infants around 7 months of age used their 2 hands infrequently for reaching. Occurrences of bimanual reaching were particularly low at the session preceding the first bimanual success at a bimanual task. This suggests that the temporal coincidence between greater independence of the 2 hands and progress in bimanual coordination of complementary movements acts in 2 directions: Infants may be more at ease when using their 2 hands in differentiated patterns as the hands move less in synchrony, but, in turn, they may be less likely to move their hands in synchrony as they anticipate mirror manipulations of the object less. The frequency of bimanual reaching increased toward the end of the 1st year. This might have been caused by an increase in the repertoire of bimanual asymmetrical object manipulations and by the fact that the development of bimanual coordination allows infants to manipulate objects with complementary movements even after a bimanual approach toward the object.

bimanual coordination↗

PubMed1999

Dynamics of 1:2 Coordination: Temporal Scaling, Latent 1:1, and Bistability.

The simplest interlimb multifrequency coordination of 1:2 can be performed at different speeds and in at least two different styles or modes. The effects of speed and mode (in-phase or antiphase) were evaluated in a bimanual 1:2 rhythmic task in which participants (N = 8) oscillated hand-held pendulums with identical or different uncoupled frequencies. A motion equation in relative phase that captures the asymmetries of components and task predicted the 1:2 coordination equilibria resulting from temporal scaling. According to the experimental results, both coordination modes proved to be equally stable. More detailed analyses of individual trials showed signs that the more fundamental 1:1 coordination intruded into the 1:2 coordination.

Journal Article↗

PubMed2005

Effects of interlimb and intralimb constraints on bimanual shoulder-elbow and shoulder-wrist coordination patterns.

The present study addressed the interactions between interlimb and intralimb constraints during the control of bimanual multi-joint movements. Participants performed eight coordination tasks involving bilateral shoulder-elbow (expt I) and shoulder-wrist (expt II) movements. Three principal findings were obtained. First, the principle of muscle homology (in-phase coordination), giving rise to mirror symmetrical movements with respect to the midsagittal plane, had a powerful influence on the quality of interlimb coordination. In both experiments, the accuracy and stability of inter- and/or intralimb coordination deteriorated as soon as the antiphase mode was introduced in one or both joint pairs. However, the mutual influences between bilateral distal and proximal joint pairs varied across coordination tasks and effectors. Second, the impact of intralimb coordination modes on the quality of intralimb coordination was inconsistent between adjacent (expt I) and non-adjacent joint (expt II) combinations. Third, the mode of interlimb coordination affected the quality of intralimb coordination, whereas strong support for the converse effect was not obtained. Taken together, these observations point to a hierarchical control structure whereby interlimb coordination constraints have a stronger impact on the global coordination of the system than intralimb constraints, whose impact is substantially dependent on effector and task. The finding that intralimb coordination is subordinate to interlimb coordination during the production of bimanual multi-joint coordination patterns indicates that symmetry is a major organizational principle in the neural control of complex movement.

Adult↗

PubMed2003

Head movements destabilize cyclical in-phase but not anti-phase homologous limb coordination in humans.

The present study addressed the role of head movements in the coordination of the homologous upper or lower limbs in supine normal subjects. Consistent with previous research, in-phase mirror symmetrical movements were performed more accurately and consistently than anti-phase movements. However, inclusion of head movements destabilized in-phase but not anti-phase homologous limb coordination, in contrast to previous work demonstrating a higher vulnerability of anti-phase than in-phase coordination to various experimental perturbations. It was observed that the head moved in the same direction as the limbs during anti- but not during in-phase coordination. Furthermore, the interlimb patterns also affected the head rotations that were lower in spatiotemporal consistency and less consistently coupled with the limbs during in-phase than during anti-phase coordination. These findings provide new insights into the coalition of egocentric and allocentric constraints during interlimb coordination.

Adult↗

PubMed1991

Dynamical substructure of coordinated rhythmic movements.

A coordinated rhythmic movement pattern is a dynamical activity involving many hidden layers of rhythmic subtasks. To investigate this dynamical substructure, spectroscopic concepts and methods were applied to an interlimb rhythmic movement task requiring 1:1 frequency locking of two hand-held pendulums in 180 degrees phase relation. The pendulums could be of identical or very different dimensions, thereby providing different values of the ratio omega of uncoupled frequencies. Analyses focused on the power spectrum of continuous relative phase as a function of variation in omega. Predictions were derived from the theories of mode locking and fractal time. Experimental results were in agreement with theoretical expectations and were discussed in terms of the possible recruiting of rhythmic subtasks in the assembling of interlimb absolute coordination, the interdependence of these subtasks, and the general dynamical principles that relate coordinative processes occurring at different length and time scales.

Adult↗

PubMed1997

Coordination Dynamics of the Bipedal Galloping Pattern.

A motion equation in relative phase was developed that incorporates the spatial-temporal pattern of the bipedal gallop along with the more commonplace patterns of the bipedal jump and walk-run. In 3 experiments, human participants (N = 6 per experiment) simulated the bipedal gait patterns through the rhythmic motions of hand-held pendulums. Predictions of the motion equation for coordination equilibria and their respective degrees of stability were confirmed. In particular, the gallop pattern was less stable than the fundamental in-phase and antiphase patterns but changed in qualitatively similar ways to those gaits as a function of limb asymmetry and movement frequency. The relation between the modeled coordination dynamics and the kinematic characteristics of real bipedal galloping is discussed.

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PubMed1999

Dual-Finger Preferred-Speed Tapping: Effects of Coordination Mode and Anatomical Finger and Limb Pairings.

Interlimb and interfinger coordination were examined in a dual-finger tapping paradigm in which 16 subjects performed at preferred frequencies. Three bimanual finger combinations, in random order (2 index; 2 middle; and 1 index and 1 middle), were performed in in-phase and antiphase coordination modes, in addition to 1 unimanual combination (antiphase index-middle). Relative phase means were within 3&percent; accuracy for all conditions. A lower tapping frequency was found in all antiphase vs. in-phase conditions, accompanied by lower phasing variability and lower intrafinger consistency in the antiphase. When frequency was changed from the preferred rate, the 2 coordination modes became more alike in variability and, within the same frequency range, demonstrated no significant differences. The bimanual mixed-fingers tapping tended to have significantly lower phasing values (a small fixed point drift) and higher tapping frequencies than the symmetric conditions. The unimanual task was similar to all other antiphase conditions. Changes in preferred frequency with different coordination modes may be related to differing perceptual informational constraints. Current models addressing natural frequencies of coupled oscillators do not account for the present data.

Journal Article↗

PubMed1997

Neural control of interlimb oscillations. I. Human bimanual coordination.

How do humans and other animals accomplish coordinated movements? How are novel combinations of limb joints rapidly assembled into new behavioral units that move together in in-phase or anti-phase movement patterns during complex movement tasks? A neural central pattern generator (CPG) model simulates data from human bimanual coordination tasks. As in the data, anti-phase oscillations at low frequencies switch to in-phase oscillations at high frequencies, in-phase oscillations occur at both low and high frequencies, phase fluctuations occur at the anti-phase in-phase transition, a "seagull effect" of larger errors occurs at intermediate phases, and oscillations slip toward in-phase and anti-phase when driven at intermediate phases. These oscillations and bifurcations are emergent properties of the CPG model in response to volitional inputs. The CPG model is a version of the Ellias-Grossberg oscillator. Its neurons obey Hodgkin-Huxley type equations whose excitatory signals operate on a faster time scale than their inhibitory signals in a recurrent on-center off-surround anatomy. When an equal command or GO signal activates both model channels, the model CPG can generate both in-phase and anti-phase oscillations at different GO amplitudes. Phase transitions from either in-phase to anti-phase oscillations, or from anti-phase to in-phase oscillations, can occur in different parameter ranges, as the GO signal increases.

Extremities↗

PubMed2002

Spontaneous leg movements in infants with and without periventricular leukomalacia: effects of unilateral weighting.

The present study was designed to investigate the contribution of the corticospinal tracts in the regulation and coordination of interlimb couplings and the spatio-temporal organization of kicking movements in young infants. Both healthy infants and those with differing degrees of periventricular leukomalacia (PVL) were subjected to a unilateral weight manipulation at the (corrected) age of 26 weeks. Infants with PVL were grouped according to the amount of damage in the area in which the corticospinal tracts are located as shown by neonatal MRI and confirmed with MRI recordings at 18 months. The main question asked was whether unilateral weighting would reveal different adjustment in infants with and without PVL and whether these differences were related to the severity of the lesions, if present. The major finding was that no differences were evident between groups in adjusting to the weight manipulation with regard to the tightness of interlimb couplings. This finding corroborates the suggestion that corticospinal influences are not directly involved in the regulation of these parameters. Although the same conclusion could be drawn concerning the kinematic details of kicks on the basis of group data, individual analyses revealed that kinematics in a few infants with PVL were markedly affected by the weighting. Thus, combining group with individual analyses may have additional value in the clinical interpretation of the effects of PVL on the neural functions of young infants.

Brain↗

PubMed1998

Early walking in the neonatal rat: a kinematic study.

The development of the early stage of locomotion (between Postnatal Days 3 and 10) was studied in newborn rats. At this age, rats are known to perform limited locomotor activities, consisting of an inefficient nonpostural gait termed crawling. By providing appropriate olfactory stimulation, it was possible to override the pups' reluctance to walk and to discover their actual locomotor abilities. The step period decreased from 1,200 ms to 900 ms from Postnatal Days 4 to 9, showing both a regular decrease in the swing and a discontinuous decrease in the stance phase. The fore- and hindlimb periods stabilized early on an alternate pattern of coupling. The ipsilateral coupling shifted progressively from 220 degrees to 260 degrees in relation with the change in the gait pattern. In parallel with the change in timing, the newborn rats showed gradual changes in the foot position and in the interlimb spatial coordination. These results show that quadruped locomotion develops before postural control is acquired, in a continuous process as the nervous system develops.

Animals↗

PubMed1996

Diffusive, Synaptic, and Synergetic Coupling: An Evaluation Through In-Phase and Antiphase Rhythmic Movements.

The in-phase and antiphase patterns of interlimb l:1 frequency locking were contrasted with respect to models of coordination dynamics in biological movement systems that are based on diffusive coupling, synaptic coupling, and synergetic principles. Predictions were made from each model concerning the stable relative phase phi between the rhythmic units, its standard deviation SDphi and the self-chosen coupled frequency omegasubc;. The experimental task involved human subjects oscillating two handheld pendulums either in-phase or antiphase. The eigenfrequencies of the two hand-pendulum systems were manipulated by varying the length and mass of each pendulum individually. Relative to an eigenfrequency difference of Delta equal to zero, |Deltaomega| > 0 displaced phi from phi = 0 and phi = pi, and amplified SDphi. omegasubc; decreased with |Deltaomega|. Both the displacement of phi and SDphi were greater in the antiphase mode. Additionally, the displacement of phi increased more sharply with |Delta| for antiphase than for in-phase coordination. In contrast, omegasubc; was identical for the two coordination modes. Of the models of interlimb coordination dynamics, the synergetic model was the most successful in addressing the pattern of dependencies of phi and SDphi. The specific forms of the functions relating omegasubc; and phi to Deltaomega pose challenges for all three models, however

Journal Article↗

PubMed1995

Bipedal reflex coordination to tactile stimulation of the sural nerve during human running.

1. Cutaneous reflex responses were elicited during human running (8 km/h) on a treadmill by electrical stimulation of the sural nerve at the ankle. Stimulus trains (5 pulses of 1 ms at 200 Hz) at three nonnociceptive intensities, which were 1.5, 2.0, and 2.5 times perception threshold (PT), were delivered at 16 phases of the step cycle. For 11 subjects the surface electromyographic (EMG) activity of both the ipsilateral and contralateral long head of the biceps femoris (iBF and cBF, respectively), the semitendinosus (iST and cST), the rectus femoris (iRF and cRF), and the tibialis anterior (iTA and cTA) were recorded. 2. During human running nonnociceptive sural nerve stimulation appears to be sufficient to elicit large, widespread and statistically significant reflex responses, with a latency of approximately 80 ms and a duration of approximately 30 ms. These reflex responses seem to be an elementary property of human locomotion. This is indicated by the occurrence of the responses in all subjects, the consistency of most of the reflex patterns across the subjects and, apart from a small amount of habituation, the reproducibility of the responses during the course of the experiment. 3. The responses are modulated continuously throughout the step cycle such that their magnitude does not in general covary with the background locomotor activities. This is observed most clearly in iST, iTA, and cTA for which statistically significant reflex reversals are demonstrated, and in cRF and cTA for which the responses are gated during most of the step cycle. 4. The response magnitude generally increases as a function of increasing intensity, whereas the phase-dependent reflex modulation is intensity independent. 5. A functional dissociation within the ipsilateral hamstring muscles is demonstrated: the iBF and iST show an antagonistic reflex pattern (facilitatory and suppressive, respectively) during the periods of synergistic background locomotor activity in the step cycle. Contralaterally, however, the cBF and cST are reflexively activated as close synergists during these periods. 6. The reflex responses and their phase-dependent modulation are different for the homologous muscles in the two legs. Yet, some similarities are observed. These are present rather with respect to the phase of the corresponding leg than with respect to the phase of the stimulated leg. Both observations suggest that the phase-dependent reflex modulation is controlled separately in the ipsilateral and contralateral legs. 7. The response simultaneity in all investigated muscles supports the notion of a coordinated cutaneous interlimb reflex during human running.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1976

[Responses of lumbar flexor motoneurons to stimulation of limb afferents].

Interaction of PSPs elicited by stimulation of hindlimb and forelimb afferent nerves was studied in lumbar flexor motoneurons of anesthetized cats. Activation of forelimb afferents evoked EPSPs of considerable duration; no IPSPs were observed. Stimulation of hindlimb flexor afferents evoked EPSPs in the same motoneurons, their early component being of segmental origin and their late component--of spino-bulbo-spinal one. Interaction of afferent systems of fore--and hindlimbs caused a long-lasting depression of EPSPs. The depression of EPSPs was not followed by generation of IPSPs in motoneurons, Possible integrative levels of interlimb inhibitory coordination are discussed.

Animals↗