Identical Movements Research Articles

Spatial Error Detection and Assimilation Effects in Rapid Single and Bimanual Aiming Movements

In 2 experiments, spatial error detection capability and movement accuracy were investigated in both single and bimanual rapid aiming movements. In both experiments, right-handed college-age participants (N = 40 [Experiment 1]; N = 24 [Experiment 2]) used light, aluminum levers to make quick single and dual reversal movements in the sagittal plane in a time to reversal of 210 ms to either the same or different target locations involving identical (Experiment 1) or mirror-image (Experiment 2) movements. In Experiment 1, the shorter-distance limb overshot the target by 15–23% when paired with a limb traveling at least 20° farther, but no spatial assimilations were shown when movements differed by 20° or less. In Experiment 2, the shorter-distance limb overshot 22–29% when paired with a limb traveling 20° farther, but spatial assimilations were not mitigated when both limbs moved to the same target position. Participants underestimated movement amplitude in all dual conditions but particularly when spatial assimilations were noted. Correlations between actual and estimated errors decreased from single to dual trials in both experiments. The findings suggest that spatial assimilations are caused by bimanual differences in movement amplitude, regardless of movement direction, and that individuals have greater difficulty identifying errors in simultaneous actions, especially when spatial assimilations are present, than identifying errors in single-limb actions.

REPETITIVE SENSORIMOTOR TRAINING FOR ARM AND HAND IN A PATIENT WITH LOCKED-IN SYNDROME

The locked-in syndrome is characterized by quadriplegia, preserved consciousness and inability to respond to the outside world. In recent years, the repetitive execution of identical movements has been demonstrated to be crucial for the recovery of arm and hand function in stroke patients. The present study aimed at investigating the efficiency of repetitive training in a patient suffering from locked-in syndrome due to an occlusion of the basilar artery. Seven months after the brainstem lesion and after a 15-week period of standard inpatient therapy, the repetitive training was applied to the (most affected) right upper extremity in addition to usual therapy. After 42 weeks of the repetitive training for the right arm, it was applied to the left arm. The ranges of active motion as well as functional motor capacity and muscle tone were regularly assessed. During those phases when the repetitive sensorimotor training was applied to the right or left arm, the ranges of active motion, muscle strength and functional motor capacity of the trained arm increased significantly accompanied by a continuous normalization of muscle tone in the flexor muscle groups. Since the prominent functional improvements of the right and left arms were observed during those phases when the repetitive training was applied, these effects were likely to be due to the training rather than to the standard rehabilitation program or extraneous influences. The repetitive sensorimotor training, therefore, appears to be appropriate to improve motor function of the arm and hand and to accelerate the time course of recovery even in patients with almost complete central paralysis of both arms.

Facilitation of motor evoked potentials after repetitive voluntary hand movements depends on the type of motor activity

Recent neurophysiological studies suggest that repetitive execution of identical movements is crucial for motor learning. During and after repetitive motor action, changes in motor cortical excitability have been demonstrated by means of transcranial magnetic stimulation. Nevertheless, the frequency and intensity of movement repetition that are necessary to achieve an optimal improvement in motor function are unknown. Fourteen healthy volunteers participated in the present study, which deals with the post-exercise facilitatory and/or inhibitory effects of 5 different motor conditions, including repetitive isotonic contractions at the wrist at two different velocities and two different forearm positions, a sustained isometric hand extension and repetitive hand extensions at the wrist induced by means of transcutaneous electrical muscle stimulation. The modification of muscular response potentials in the extensor carpi radialis muscle was measured following the various motor tasks and the electrical muscle stimulation. The only statistically significant facilitatory effect was observed following an extension-relaxation task at low frequency. Furthermore, the duration of transcranially induced silent periods showed a significant reduction after this motor task.

THE RATIONALE FOR AQUATIC PHYSICAL THERAPY IN THE SHOULDER 1074

Our purpose was to compare the neural activation of rotator cuff and shoulder synergist muscles during aquatic therapy to identical movements on dry land. The EMG activity of 6 muscles was examined on the nondominant shoulders of six subjects. Water-proof, indwelling wire electrodes(supraspinatus, infraspinatus, and subscapularis) and surface electrodes(anterior, middle and posterior deltoids) were placed. Each subject performed elevation (0°-90°) in the scapular plane with neutral rotation. The exercises were performed at three different speeds of elevation (3s, 2s, and 1s). Three trials at each speed were averaged. Integrated EMG values were determined for each trial and the percentage of maximal activation (% MVC) of each muscle was calculated for each speed. The mean% MVC was determined for each of the three test speeds on land and in water. A dependent t-test was used for statistical analysis. For all six muscles tested, neural activation during the 3s and 2s test speeds was significantly less (p < 0.05) when performed in water. During the l-second test, there was a trend towards greater activation for all muscles when the exercise was performed in water. Early active range of motion in the shoulder following injury or surgery is the key to the restoration of normal shoulder kinematics and early return of shoulder function. Aquatic physical therapy allows active shoulder motion in an environment in which the injured or surgically repaired tissues are not adversely stressed. This active motion in water is both comforting to the patient and precedes when it would be safe to perform it on dry land. This study confirms the lessened tissue tension as evidenced by the significantly decreased muscle neural activation in water versus dry land. Our clinical experience with over 500 patients in aquatic physical therapy has confirmed both its efficacy and safety in the immediate post-surgical or post-injury setting.

The Metabolic Cost of Two Ranges of Arm Position Height with and without Hand Weights during Low Impact Aerobic Dance

To determine the energy cost of low impact aerobic dance while varying arm movement height and the use of hand weights, 10 adults volunteered to participate in four choreographed trials. All trials consisted of identical leg movements. Arm movements, however, were performed above shoulder level both with and without 0.9-kg hand weights and below shoulder level both with and without 0.9-kg hand weights. Open circuit spirometry was employed throughout the 10-min videotape guided trials, and heart rate was measured by telemetry. Neither the use of hand weights nor the change in arm position height significantly altered the energy cost of low impact aerobic dance. However, heart rate responses were significantly different. Caution should be observed by aerobics instructors and participants as to the use of heart rate as an indicator of intensity for low impact aerobic dance.

Relationship of intrinsic connections to forelimb movement representations in monkey motor cortex: a correlative anatomic and physiological study

1. Intracortical microstimulation (ICMS) and horseradish peroxidase (HRP) histochemistry were combined to examine the relationship between intrinsic connections and intracortical microstimulation sites eliciting evoked movements in the forelimb representation of adult macaque monkey motor cortex. 2. The distribution of sites from which stimulation-evoked movements about individual forelimb joints were elicited under anesthesia varied considerably among animals. Identical movements could often be elicited from multiple, noncontiguous sites. 3. After single, small extracellular HRP injections at sites from which thumb movement was evoked, small groups of retrogradely labeled cells and dense patches of axon terminations were found scattered across a wide area of the forelimb representation. Terminal patches were discontinuous and arose from horizontal, intracortical axons. 4. Correlating the HRP labeling with the physiologically defined movement maps revealed a profuse set of intrinsic, bidirectional connections that connect digit representations and representations of movements about the wrist, elbow, and shoulder. 5. HRP injections placed in the forelimb representation close to the physiologically defined face representation resulted in virtually no retrogradely labeled cells or terminal fiber labeling that crossed into the face representation. A patch of anterolaterally placed label that was present may be the dissociated rostrolateral arm area of other authors. 6. Taken together, these data suggest that extensive, horizontally oriented, intrinsic axon collaterals provide inputs to many different forelimb movement representations and may be recruited during complex movements to coordinate the activity of motor cortical zones whose predominant output is to forelimb muscle groups acting synchronously.

Social smiling in normal and down syndrome infants: A comparative study

The aim of this work has been to compare social smiling in Down syndrome (mongolism) and normal infants, attending especially to the brow movements that appear before it. Facial responses of eight Down syndrome and eight normal infants from three to five months were analized by means of an anatomically based measurement technique during face-to-face interactions with their mothers. Despite their mental retardation, Down syndrome infants showed identical muscle movements as normal infants before and during smiling. However, some differences were found in smile frequency and leght, as well as in the brow movements frequency before smiling. Results are discussed in terms of the psychophisiological dysfunction of Down syndrome infants that are originated by a chromosome imbalance.

International Body Language and Effective Marketing

International executives' jobs become easier if they are more sensitive to the nonverbal cues they receive from people of different cultures. Research findings of special interest to these readers are cited from the discipline of kinesics, popularly called body language. After a brief introduction to the rigorous methodology used to determine whay body movements mean, the paper explores whether identical movements mean the same thing in different cultures. Findings from many nations are given. The paper ends by showing business people how to send the correct signals in different nations and how to develop skills in interpreting body signals and lying gestures in many parts of the world.

Simultaneous ground-based observations of the plasmapause and the F-region mid-latitude trough

The plasmapause and the mid-latitude ionospheric trough have been observed simultaneously from two Antarctic stations, Halley and Faraday, during five winter nights covering a range of geomagnetic disturbance conditions. The equatorial radius of the plasmapause was measured using whistlers recorded at Halley, whilst the poleward edge of the trough was located from ionospheric soundings at one or other of the stations. Before midnight the trough was well poleward of the plasmapause (by 1–2 L) when first observed (typically at ~21 LT), but then moved rapidly equatorwards. After local magnetic midnight the two features were roughly coincident, and in general moved slowly to lower L-shells with increasing local time. At no time were there simultaneous and identical movements of the two features, suggesting a lack of coupling between them. Agreement of the observations with statistical studies and models was fair, given the considerable variability among the five cases studied. For the geomagnetically quieter nights the trough data fit the Spiro model predictions, whereas in the most disturbed case, agreement is better with the Quegan et al. model. The latter model predicts a difference in L between the two features which would fit the data better if shifted 1–2 h later in local time.

Binary choice reaction time as a function of the relationship between durations and forms of responses.

In a choice between responding with the left or right hand, some kinds of differences between the movements increase RT (Reaction Time) while others do not. Of the first kind are differences in form, while differences in the finger used are of the latter kind. In previous experiments differences in form were confounded with differences in duration. Since there is some indication that a difference in duration is sufficient to lengthen RT, both characteristics were varied separately. It turned out that a difference in form (duration being constant) has essentially the same effects as a difference in duration (form being constant): Mean RT is longer, variability of RT and MT (movement time) is larger, and frequency of choice errors is smaller than in choice between identical movements. These effects, which seem to be associated with choice between movements of different temporal patterns, are interpreted in terms of advance specification of movement parameters. Additional results on the relationship between response duration and RT suggest that RT does not depend on duration (or velocity) per se, but on how much the duration deviates from quickest performance.

Force gradation and motor unit activity during voluntary movements in man

The density of spikes, or spike output (SO), recorded by means of 3 selective bifilar electrodes simultaneously implanted in the biceps brachii has been studied during elbow flexions performed against inertia and with a variable velocity (anisometric, anisotonic contractions). The total numbers of motor unit (MU) potentials were sequentially measured during intervals of 30 msec, and the force (F) values were calculated during the same intervals. The SO obtained during movements of very similar mechanical characteristics was different from one movement to another. However, when a small number of identical movements was summed, an average SO ( SO ) was obtained that was representative of the ‘instantaneous’ global activity of the biceps. Taking into account the respective values of the bin duration and of the interval between two succissive potentials of a single MU, the increase of SO represents the recruitment of MU during the phase of force increase of the movement. Relations have been established between successive values of SO and F̄ as well as between their peak values. From these relations it is concluded that the shape of force increase in anisometric anisotonic conditions is mostly related to that of MU recruitment, although the absolute value of force depends on both the firing frequency and the number of active MUs.

Sensitivity and specificity of echocardiographic diagnosis of pericardial effusion.

In order to evaluate the reliability and sensitivity of echocardiograms for detecting and quantitating pericardial effusion, 41 patients had echocardiograms on the day prior to cardiac operation. A fluid trap was used to aspirate the pericardium at operation. Thirty-nine of 41 patients had echocardiograms of diagnostic quality. In 25 patients, the echocardiogram was negative for pericardial effusion, with 0-16 ml identified at operation. In 13 patients, the echocardiogram was positive for pericardial effusion, with 15-775 ml aspirated at operation. A transition of patterns of relative posterior epicardial-pericardial movement was noted as the pericardial fluid volume increased. More than 15 ml was always found when a posterior echo-free space persisted throughout the cardiac cycle between a flat pericardium relative to the epicardium. In the presence of such a posterior echo-free space, a large anterior echo-free space made a moderately large pericardial effusion likely. In the absence of this diagnostic posterior echo-free space, an anterior echo-free space had no diagnostic significance, as it was found in 11 patients with less than 16 ml of pericardial effusion. A small posterior echo-free space persisting throughout the cardiac cycle between pericardial and epicardial echoes demonstrating virtually identical movements was found in two patients without any surgical evidence for pericardial effusion, but with evidence of adhesive fibrocalcific pericardial disease. A method of estimating pericardial volume is proposed, which uses the difference between the cubed diameters at the end-diastole of the pericardium and epicardium.

On the Coherence of Christian Atheism

I begin with some remarks on Christian Atheism and the Death of God Theology. These are not, as might be thought, identical movements. Rather, as I shall try to make clear, Christian Atheism is one form that the Death of God theology has assumed.

Bioelectric regulation of tentacle movement in a dinoflagellate.

ABSTRACT Recurring extensions and flexions of the food-gathering tentacle of Noctiluca miliaris occur spontaneously. Identical movements can be evoked by appropriate electrical stimulation. Spontaneous recurring potential wave forms (TRPs) were recorded from the vacuole of the luminescent form of Noctiluca during movements of the tentacle. The basic TRP wave form consists of a characteristic negative-going spike which arises at −20 to −30 mV. from the slowly redeveloping negativity of a pre-spike depolarization, and is followed by a quasi-stable post-spike d.c. level of relative vacuolar negativity (−45 to −60 mV.). The TRP complex, similar in shape to that which occurs spontaneously, follows an intracellularly applied current pulse of either polarity if the vacuolar potential is at the post-spike level. The duration of the evoked pre-spike wave is related to the current intensity and duration. During the pre-spike state outward current is ineffective, although a TR spike occurs in response to inward current. The TRP is distinct in its behaviour and wave form from the flash-triggering potential, which can be evoked in the same cell, even though both exhibit all-or-none spikes. Simultaneous recordings of intracellular potentials and movements of the tentacle showed a consistent temporal relationship between potential changes and subsequent movement. Extension of the tentacle begins 1–2 sec. after the spike and flexion begins within i sec. after beginning of the pre-spike wave. Tentacle movement ceased in Ca-free sea water even though the cyclic potential changes continued normally. Electron micrographs of the tentacle showed longitudinal aggregations of microtubules near the outer surface of the peripheral cytoplasm. It is proposed that contraction of these microtubules is the immediate cause of tentacle movements.

Timing of Two Simultaneous Movements of Arms and Legs

Abstract The ability of people to perform simultaneous movements involving speed and accuracy, and the relationships among the several time measures for these movements were studied. Five movement tasks using two simultaneous movements of arms and legs were performed. Reliability of time measures ranged between 0.830 and 0.988. There were no significant differences between the two tasks involving an arm and a leg. Reaction time for tasks involving an arm and leg was slower than for tasks involving two arms. An increase in task complexity resulted in an increase in starting time difference and contact time difference. Common variance between tasks for several time measures was relatively high. For all tasks, except the one using identical movements for the two arms, a consistent movement pattern was found in which the right hand started first and finished last.

Morfologia do Mycobacterium leprae hominis e do M. leprae muris: estudo baseado na microscopia electrônica e de contraste de fases

Hansen's Bacillus: By electron microscopy this bacillus shows membrane and halo, this being more visible when sorrounding the globi or bundles of bacilli; shows, also, free granules of various sizes which were before considered as dust of the dyes; shows external granules bound with the membrane and some times branching. By phases contrast microscopy examining leproma suspensions and subcataneous lymph at 400 x we saw many free granules with intense rotatory movement; granulated bacilli with screw, skip or stroke motion, producing slow progressive motion. All such elementes are surrounded by a halo, corresponding to the classical gloea. By a patient and delayed examination we were able to see that the internal granules are motile and help the progression of the bacilli, giving the impression that the cytoplasm is liquid. By a lasting observation we could see the larger granules form prolapse, like a pseudopode and abandon the bacilli and going in very rapid rotatory movement. There are branched bacilli; there are pedunculated fred granules like comets. The addition of a drop of formol at the preparation stops all movements. Stefansky's Bacillus: Repeated examination by RCA electron microscope, type EMU-25 of fresh suspensions of rat lepromas, led us to confirm the close relationship between human and murine leprosy agents. We examined also material from carabo (Lepra bubalorum) from Java, but due to fixation, the material was unsuitable for comparative studies. The Stefansky's bacilli showed also emmbranes and halos, internal or external granules (smaller than those of Hansen's bacillus). The bacilli shaded by chromium look thicker and shorter than those of Hansen. Due to electron bombardment both, Hansen's and Stefansky's baccilli suffer considerable alterations in their structure, showing black barrs of chromatin condensation at their extremities as also in their centers. By phase microscopy the Stefansky's bacilli showed elements with 1, 2 (bipolar), 3 or more internal small granules, developing identical movements as those of Hansen. The globi seem to be non-motile but the free bacilli appearing around the globi show intense movement. At 1000 x the examination is less satisfactory than at 400 x. The addition of formol solution in the preparation suppresses all movements, even the brownian, but the material becomes more suitable for the study of static morphology of the bacilli. CONCLUSION - The electron and phases contrast microscopy of leprous material from different types and phases of the disease may explain some of the unknown aspects of the biology and morphology of the bacilli.