Previous work from this laboratory has shown that activity in the dorsal spinocerebellar tract (DSCT) relates strongly to global hindlimb kinematics variables during passive displacements of the hindlimb. A linear relationship to limb axis orientation and length variables accounts for most of the response variance for passive limb positioning and ...

The intensity and spatial representation of electromyographical (EMG) activity were examined to characterize the effects of limb dominance and movement direction upon global synkinesis (GS). Twenty-two healthy young subjects (11 men, 11 women) with a mean age of 24.7 years participated in this study. Three trials of EMG activities from ...

On the basis of research in self-paced aiming movements, Glover [S. Glover, Separate visual representations in the planning and control of action, Behav. Brain Sci., 27 (2004) 3-24] proposed a dichotomy between visual systems that accommodate planning and on-line control of action. Specifically, the planning-versus-control model posits that the on-line ...

Functional data analysis techniques provide an alternative way of representing movement and movement variability as a function of time. In particular, the registration of functional data provides a local normalization of time functions. This normalization transforms a set of curves, records of repeated trials, yielding a new set of curves ...

People with cerebral palsy (CP) are known to rely heavily on visual guidance when making targeted upper-limb movements. In the present study, we examined whether being able to visually monitor the moving limb forms a precondition for people with CP to make accurate upper-limb movements. Eight participants with tetraparetic CP ...

Recent studies showed that the low-frequency component of local field potentials (LFPs) in monkey motor cortex carries information about parameters of voluntary arm movements. Here, we studied how different signal components of the LFP in the time and frequency domains are modulated during center-out arm movements. Analysis of LFPs in ...

The role of directional compatibility was investigated during the production of in-phase and anti-phase coordination patterns involving the four limbs as well as the head. Our first aim was to compare the quality of interlimb coordination between concordant and discordant coordination patterns across girdles at different cycling frequencies. Concordant implied ...

Suppose that the variability in our movements is caused not by noise in the motor system itself, nor by fluctuations in our intentions or plans, but rather by errors in our sensory estimates of the external parameters that define the appropriate action. For tasks in which precision is at a ...

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 ...

The issue of how the Euclidean properties of space are represented in the nervous system is a main focus in the study of visual perception, but is equally relevant to motor learning. The goal of our experiments was to investigate how the properties of space guide the remapping of motor ...

The goal of this study was to design a robot system for assisting in the rehabilitation of patients with neuromuscular disorders by performing various facilitation movements. The robot should be able to guide patient's wrist to move along planned linear or circular trajectories. A hybrid position/force controller incorporating fuzzy logic ...

Fishes require complex coordinated motions of the jaws, body and fins during feeding in order to successfully execute the strike or bite and then move away from the predation site. In conjunction with locomotor systems, sensory modalities guide coordinated feeding behavior, with vision playing an important role in many fishes. ...

The objective of this study was to determine if simple, shoulder movements use the dual control hypothesis strategy, previously demonstrated with elbow movements, and to see if this strategy also applies in the absence of visual feedback. Twenty subjects were seated with their right arm abducted to 90 degrees and ...

In two experiments, we studied intermanual interactions in bimanual reversal movements and bimanual aiming movements. Targets were presented on a monitor or directly on the table on which the movements were produced. Amplitudes for each hand were cued symbolically or spatially either in advance of an imperative signal or simultaneous ...

OBJECTIVES: To develop a method for the three dimensional analysis of body movements and body positions during the performance of circular swings on the competition mushroom, an apparatus used by young gymnasts for pommel horse training. METHODS: Five experienced male gymnasts, all of national level, performed three series of 10 ...

Observing somebody performing an action has been shown to elicit neuronal activity in the premotor cortex. This paper investigated physiological effect of observing an effortful action at the peripheral level. As Autonomic Nervous System responses reflect central nervous system processes such as movement planning and programming, it was expected that ...

Danckert and Goodale [Exp Brain Res 137:303-308 (2001)] have shown that increases in movement time as target size decreased were greater when movements were performed in the lower compared with upper visual field. On this basis, they suggested that visual feedback processing was more effective in the lower visual field. ...

Biomechanical studies often employ optical motion capture systems for the determination of the position of an object in a room-based coordinate system. This is not ideal for many types of study in locomotion since only a few strides may be collected per ;trial', and outdoor experiments are difficult with some ...

BACKGROUND: Previous attempts to measure otolith function using ocular counter-rolling have shown poor sensitivity and specificity, thereby hindering a useful clinical application. We have conducted a study to investigate whether thresholds for the perception of the direction of linear acceleration might be an alternative for the clinical evaluation of otolith ...

Despite the abundant experimental evidence for the irregular, multipeaked velocity profiles that often characterize rapid human limb movements, there is currently little agreement on how to interpret these phenomena. While in some studies these irregularities have been interpreted as reflecting a continuous control process, in others the irregularities are considered ...

The goal of this experiment was to show that expertise in interceptive actions can be explained by a shorter delay in movement regulation. In this contribution, we tested tennis experts and non-experts using a simulated interceptive task. The experimental device simulated linear motion of an object toward a target on ...

A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images ...

Previous studies on the speed and latency of convergence and divergence eye movements have produced varied, sometimes contradictory, results. Four subjects were studied and tracked 4 degrees disparity step changes for convergence and divergence at different initial target positions. Here we report that the dynamics of divergence movements not only ...

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 ...

Inspired by the pioneering work by Held and Hein (1963) on the development of kitten visuo-motor systems, we explore the role of active body movement in the developmental process of the visual system by using robots. The receptive fields in an evolved mobile robot are developed during active or passive ...

Moving to a rhythm necessitates precise timing between the movement of the chosen limb and the timing imposed by the beats. However, the temporal information specifying the moment when a beat will sound (the moment onto which one must synchronise one's movement) is not continuously provided by the acoustic array. ...

Recent neuroscience studies have been concerned with how aimed movements are generated on the basis of target localization. However, visual information from the surroundings as well as from the target can influence arm motor control, in a manner similar to known effects in postural and ocular motor control. Here, we ...

The current studies explore the informational basis of the coupling in human rhythmic movement coordination tasks. Movement stability in these tasks is an asymmetric U-shaped function of mean relative phase; 0 degrees is maximally stable, 90 degrees is maximally unstable and 180 degrees is intermediate. Bingham (2001, 2004a, 2004b) hypothesized ...

Rhythmic movement coordination exhibits characteristic patterns of stability, specifically that movements at 0 degrees mean relative phase are maximally stable, 180 degrees is stable but less so than 0 degrees, and other coordinations are unstable without training. Recent research has demonstrated a role for perception in creating this pattern; perceptual ...

In many situations successful execution of a balance-recovery reaction requires visual information about the environment. In particular, reactions that involve rapid limb movements, such as stepping, must be controlled to avoid obstacles and accommodate other constraints on limb trajectory. However, it is unknown whether the central nervous system can acquire ...

Studies of movement-related cortical potentials (MRCPs) for simple movements have shown a slowly rising negativity (Bereitschaftspotential, or BP) about 2 s prior to movement onset, centered in the bilateral sensorimotor area. However, complex movements may elicit a different temporal and spatial distribution of this pre-movement activity. In this study, 64-channel ...

Stereotyped movements displayed by 6 participants and tics displayed by 6 children were evaluated using an antecedent behavioral analysis and a force sensitive platform. We found that tics occurred more often in an alone condition when compared to high preference toy and play conditions, whereas stereotyped movements were more variable ...

Due to high redundancy of degrees of freedom in the human body, we can perform any movement, from the simplest to the most complex, in many different ways. Several studies are still trying to identify the motor strategies that master this redundancy and generate the movements whose characteristics are highly ...

Previous experiments by our group in normal gravity (1 G) have revealed spatial relationships between postural and focal components of whole-body reaching and pointing movements. We suggested that these relationships could be explained partly through the use of gravity to displace the CoM and attain the object or target position. ...

An experiment investigated systematic pointing errors in horizontal movements performed without visual feedback toward 48 targets placed symmetrically around two initial hand positions. Our main goal was to provide evidence in favor of the hypothesis that amplitude and direction of the movements are planned independently on the basis of the ...

Irregularities in the velocity profile near the end of pointing movements have been interpreted as corrective submovements whose purpose is to provide accuracy of pointing to the target. The purpose of the present study was to investigate whether two additional factors related to biomechanical properties of the arm also cause ...

Increasing evidence suggests that the visual analysis of other people's actions depends upon the observer's own body representation or schema. This raises the question of how differences in observers' body structure and schema impact their perception of human movement. We investigated the visual experiences of two persons born without arms, ...

The aim of the experiment was to investigate how bi-phasic hitting movements are organized to comply with both impact and temporal precision constraints. 'Bi-phasic' refers to a sequential movement with a preparatory movement away from the interception location followed by a strike phase. The interception location was fixed, as the ...

The cerebral cortex contains circuitry for continuously computing properties of the environment and one's body, as well as relations among those properties. The success of complex perceptuomotor performances requires integrated, simultaneous use of such relational information. Ball catching is a good example as it involves reaching and grasping of visually ...

A coordinated movement is easy to recognize, but we know little about how it is achieved. In search of the neural basis of coordination, we present a model of spinocerebellar interactions in which the structure-functional organizing principle is a division of the cerebellum into discrete microcomplexes. Each microcomplex is the ...

An important question in the field of imitation is what information is used for movement reproduction. While it is argued that relative motion information is perceived and minimised, direct evidence is lacking. In this experiment relative motion was manipulated to convey a novel kicking action. Twenty-four adults were assigned to ...

Many neurophysiological studies give evidence for a matching system between action observation and imitation. We used functional MRI to investigate the effects of different instructions for observing identical stimuli of whole-body gymnastics movements. The imitative-like observation mode asked normal human participants to observe the sequence containing repetitive parts and to ...

We have designed an economical non-invasive movement detector for small animal studies and used it for monitoring and quantifying itch in mice. The system is based on a sensitive force transducer positioned below a recording platform holding a lightweight polystyrene recording box in which an animal is placed. A programmed ...

Vision of the hand during reaching provides dynamic feedback that can be used to control movement. We investigated the relative contributions of feedback about the direction and distance of the hand relative to a target. Subjects made pointing movements in a 3-D virtual environment, in which a small sphere provided ...

The present study was undertaken to investigate the effects of physical practice on excitability changes in human primary motor cortex (M1) during motor imagery (MI). Using different intensities of transcranial magnetic stimulation (TMS), we examined changes in the motor evoked potential (MEP) of the first dorsal interosseous (FDI) muscle with ...

Human motor behavior is remarkably accurate, even though many everyday skills require flexible adjustments between motor activity and its consequences in extracorporeal space. The present study addressed two questions: first, how do people compensate for unpredictable changes in the environment, and second, how do they adapt to such changes? In ...

Differences in motion patterns subserving the same movement goal can be identified qualitatively. These alternatives, which may characterize 'movement techniques' (e.g., the stoop and the squat lifting technique), may be associated with significantly different biomechanical constraints and physiological responses. Despite the widely shared understanding of the significance of alternative movement ...

The generators and functional correlates of gamma oscillations within the sensorimotor cortex remain unclear. With the goal of locating the oscillations' sources precisely and then studying the relationship between oscillatory reactivity and ongoing movement, we recorded stereoelectroencephalograms with intracerebral electrodes in eight epileptic subjects awaiting surgical treatment. The sensorimotor cortex ...

Piezoresistive accelerometer signals are frequently used in movement analysis. However, their use and interpretation are complicated by the fact that the signal is composed of different acceleration components. The aim of the study was to obtain insight into the components of accelerometer signals from the trunk and thigh segments during ...

An improved understanding of dispersal behavior is needed to predict how populations and communities respond to habitat fragmentation. Most spatial dynamic theory concentrates on random dispersal, in which movement rates depend neither on the state of an individual nor its environment and movement directions are unbiased. We examine the neglected ...