Determination of the variation in conduction speed of motor fibers and the effects of diphenylhydantoin (Phenytoin) and diazepam (Faustan)]

The variation in the speed of conduction of motor fibers of the ulnar nerve was determined by Hopf's double-stimulus method and compared with values obtained from the duration of muscular response potentials for differently spaced points of stimulation. However, the values obtained from the difference of the duration of response potentials are inadequate since the duration of potentials cannot always be determined accurately. After a ten-day administration of faustan (15 mg per day) or phenytoin (300 mg per day) there was observed a decrease especially in the minimum rate of conduction of motor fibers of the ulnar nerve.     

Phonological transformations in conduction aphasia

Different explanations and subtypes of conduction aphasia are analyzed. Characteristics of literal paraphasias in parietal-insular conduction aphasia are discussed, emphasizing that paraphasias in conduction aphasia are articulatory-based (articulatory literal paraphasias) and due mainly to phoneme substitutions and phoneme deletions; they result basically in switches in phoneme manner and place of articulation. Similarities between errors in ideomotor apraxia and conduction aphasia language deficits are presented. It is proposed that language deviations (in oral as in written language) in conduction aphasia can be understood as a segmentary apraxia of speech.     

Spiral drawing performance as an indicator of fine motor function in people with multiple sclerosis

This study investigated spiral drawing performance as an indicator of fine motor function, as well as to gain insight into adaptive movement strategies used by people with multiple sclerosis (MS). Seven people with MS, nine younger controls (mean age of 20) and eight older controls (mean age of 40) drew spirals on a graphics tablet at a comfortable speed and size. Spirography (i.e., a subjective visual assessment of the static trace) revealed indications of reduced control of the pen for people with MS. Analysis of the movements showed that people with MS tended to draw the spirals slower and with less pen pressure than controls. All groups increased their speed and pressure along with spiral size, but this increase was much steeper for the controls. MS participants drew spirals with more variability around an ideal trajectory, highlighting fine motor control degradation. MS patients tended to use a smaller scaling ratio, resulting in smaller spirals for a given number of revolutions. The younger and older control groups drew the spirals in a similar manner, and age was not a significant factor in any of the analyses. It is argued that the relatively lower pressure used, and slower, smaller movements (particularly during the more difficult outer sections of the spiral) are in part an adaptive strategy used to reduce movement variability. These results demonstrate the utility of the analysis of spiral movements as an objective technique for assessing motor control degradation, which can compliment the subjective rating based on the static pen trace. As such, it can provide further insight into the biomechanical strategies used when performing fine movements.     

Clinical, electroneurographic and neuroautonomic findings in patients with chronic renal insufficiency and following kidney transplantation

Orientation onsigns of sensomotor polyneuritis seems appropriate for monitoring the status of patients with chronic uremia. The maximum speed of motor and F-wave transmission by the N. fibularis and the mean instantaneous arrhythmia are parameters which, before clinical symptoms appear, permit the accurate assessment of motor and vegetative lesions and may be useful as a basis on which treatment can be corrected.     

Determination of F-wave conductivity in the normal N. ulnaris]

The methodical procedure for the determination of the F-wave conductivity in the ulnar nerve (in total - conductivity, afferent, conduction frequency forearm, afferent-efferent in the proximal segment of the peripheral motor neuron) and the results of a hundred examinations are presented. The results are compared with the motor nerve conduction velocity. No influences of sex, age or the site of lead could be discovered.     

Conduction aphasia, sensory-motor integration, and phonological short-term memory - an aggregate analysis of lesion and fMRI data

Conduction aphasia is a language disorder characterized by frequent speech errors, impaired verbatim repetition, a deficit in phonological short-term memory, and naming difficulties in the presence of otherwise fluent and grammatical speech output. While traditional models of conduction aphasia have typically implicated white matter pathways, recent advances in lesions reconstruction methodology applied to groups of patients have implicated left temporoparietal zones. Parallel work using functional magnetic resonance imaging (fMRI) has pinpointed a region in the posterior most portion of the left planum temporale, area Spt, which is critical for phonological working memory. Here we show that the region of maximal lesion overlap in a sample of 14 patients with conduction aphasia perfectly circumscribes area Spt, as defined in an aggregate fMRI analysis of 105 subjects performing a phonological working memory task. We provide a review of the evidence supporting the idea that Spt is an interface site for the integration of sensory and vocal tract-related motor representations of complex sound sequences, such as speech and music and show how the symptoms of conduction aphasia can be explained by damage to this system.     

Simulation study of a decision-making model of squash competition, phase two: Testing the model through the use of computer simulation

This study aims at verifying the inner validity and logic of a squash competition decision-making model through the use of computer simulation. The model defines the cognitive-decisional strategy of the defending player (D) when selecting a motor reaction in response to his opponent's shot. Computer simulation of the model was carried out on a PDP-10 computer using a recent version of UCI-LISP. Protocol analysis data pertaining to the nature of the information D processes when awaiting the attacking player's shot were fed into the simulation program in order to examine the extent to which the model can reproduce decisions reached in various defensive contexts. Simulation results reveal that the proposed model can account for a substantial part of the variation in the speed and accuracy of D's motor reaction in real sport situations. Several factors like time pressure, expectancies, uncertainty, recency and familiarity of the relationship between signal and response appear to affect D's motor response via the cognitive-decisional strategy employed by the defending player. Particular discrepancies observed between simulation results and decisions reached by expert players in specific defensive situations nevertheless indicate that the decision rule utilized within the present model needs to be refined. In this regard, several issues are discussed and suggestions for further simulation studies are put forward in order to account more precisely for the various features characterizing the defensive player's motor reaction in real sporting context.     

Motor performance improved by exercises in cerebral ischemic rats

Physical exercise may induce neuroprotective effects against brain damage after stroke. The authors aimed to investigate the effects of various exercises on motor function, striatal angiogenesis, and infarct volume in cerebral ischemic rats. Adult male Sprague Dawley rats were subjected to middle cerebral artery occlusion and randomly assigned to 1 of the 4 groups: Rota-rod training, lower speed treadmill training, higher speed treadmill training, or no exercise control. Motor function, striatal angiogenesis, and infarct volume were evaluated before or after motor training. After training, motor function and striatal angiogenesis changed significantly in Rota-rod and higher speed treadmill training groups as compared with the control group. Improvement in motor function significantly correlated with striatal angiogenesis after motor training. Infarct volumes were significantly decreased in lower and higher speed treadmill training groups. The results indicated that both motor training procedures can be used as effective training programs in stroke rehabilitation.     

The change in perceived motor competence and motor task values during elementary school: A longitudinal cohort study

Participation in motor activities is essential for social interaction and life satisfaction in children. Self‐perceptions and task values have a central position in why children do or do not participate in (motor) activities. Investigating developmental changes in motor self‐perceptions and motor task values in elementary school children would provide vital information about their participation in motor activities. We therefore examined the change in, and associations between, self‐perceptions and task values of fine motor competence, ball competence, and athletic competence in 292 children from kindergarten to grade 4. We also investigated differences between boys and girls, and between children with motor problems and typically developing children. Results indicated that self‐perceptions and task values are domain specific and differ between boys and girls, but not between children with motor problems and typically developing children. Self‐perceptions were not associated with task values. Educators should address specific self‐perceptions to enhance participation into the corresponding motor activities in children between kindergarten and grade 4, and differences in self‐perceptions and task values between boys and girls should be taken into account.     

Object processing for action across childhood

Human adults process and select the opportunities for action in their environment rapidly, efficiently, and effortlessly. While several studies have revealed substantial improvements in object recognition skills, motor abilities, and control over the motor system during late childhood, surprisingly little is known about how object processing for action develops during this period. This study addresses this issue by investigating how the ability to ignore actions potentiated by a familiar utensil develops between ages 6 and 10 years. It is the first study to demonstrate that (1) the mechanisms that transform a graspable visual stimulus into an object‐appropriate motor response are in place by the sixth year of life and (2) graspable features of an object can facilitate and interfere with manual responses in an adult‐like manner by this age. The results suggest that there may be distinct developmental trajectories for the ability to ignore motor responses triggered by visual affordances and the stimulus response compatibility effects typically assessed with Simon tasks.     

Brief report: Response inhibition and processing speed in children with motor difficulties and developmental coordination disorder

A previous study reported that children with poor motor skills, classified as having motor difficulties (MD) or Developmental Coordination Disorder (DCD), produced more errors in a motor response inhibition task compared to typically developing (TD) children but did not differ in verbal inhibition errors. The present study investigated whether these groups differed in the length of time they took to respond in order to achieve these levels of accuracy, and whether any differences in response speed could be explained by generally slow information processing in children with poor motor skills. Timing data from the Verbal Inhibition Motor Inhibition test were analyzed to identify differences in performance between the groups on verbal and motor inhibition, as well as on processing speed measures from standardized batteries. Although children with MD and DCD produced more errors in the motor inhibition task than TD children, the current analyses found that they did not take longer to complete the task. Children with DCD were slower at inhibiting verbal responses than TD children, while the MD group seemed to perform at an intermediate level between the other groups in terms of verbal inhibition speed. Slow processing speed did not account for these group differences. Results extended previous research into response inhibition in children with poor motor skills by explicitly comparing motor and verbal responses, and suggesting that slow performance, even when accurate, may be attributable to an inefficient way of inhibiting responses, rather than slow information processing speed per se.     

NEW CONCEPTUALIZATIONS OF PRACTICE: Common Principles in Three Paradigms Suggest New Concepts for Training

We argue herein that typical training procedures are far from optimal. The goal of training in real-world settings is, or should be, to support two aspects of posttraining performance: (a) the level of performance in the long term and (h) the capability to transfer that training to related tasks and altered contexts. The implicit or explicit assumption of those persons responsible for training is that the procedures that enhance performance and speed improvement during training will necessarily achieve these two goals. However, a variety of experiments on motor and verbal learning indicate that this assumption is often incorrect. Manipulations that maximize performance during training can be detrimental in the long term: conversely, manipulations that degrade the speed of acquisition can support the long-term goals of training. The fact that there are parallel findings in the motor and verbal domains suggests that principles of considerable generality can be deduced to upgrade training procedures.     

Comparison of muscle functions during three contrasting abdominal exercises

That different amplitudes of muscle activities during various abdominal exercises not only reflect the inherent differences in motor control but movement speed as well was hypothesized. 20 healthy adults (M age = 23 yr.) performed three exercises that involved varying amounts of trunk control: the partial sit-up, full sit-up, and AbSlide roll. Covariate analyses indicated that the amplitude of muscle activities could be partitioned into three categories: motor control and scaling (speed and amplitude), scaling only, and motor control only. Overall, the AbSlide exercise activated the most amount of muscular activity, followed by the full and partial sit-up exercises. Results are discussed in terms of how the various muscles contribute to motor control and velocity scaling.     

The effects of fluent levels of Big 6 + 6 skill elements on functional motor skills with children with autism

Functional motor skills are often taught using chaining procedures. Research suggests that chaining procedures are not likely to be effective if they do not focus on the accuracy and speed of composite skill completion. Precision teaching (PT) research suggests that improved performance of a composite skill can be achieved if the performance speed of the component behaviors is increased. This study assessed the effects of repeated timed practice of component motor skills on speed and accuracy of composite skills and the effects of fluent component motor skills on the completion of daily living composite skills. Three children with autism participated. The results suggest that all participants were able to perform the component skills at their individual aims and performed most of the component skills at fluent levels as assessed by retention and endurance checks. Each participant increased the number of composite skill steps performed independently and one decreased the overall time to complete the composite skill. Copyright © 2010 John Wiley & Sons, Ltd.     

Gestalt principles in the control of motor action

We argue that 4 fundamental gestalt phenomena in perception apply to the control of motor action. First, a motor gestalt, like a perceptual gestalt, is holistic in the sense that it is processed as a single unit. This notion is consistent with reaction time results indicating that all gestures for a brief unit of action must be programmed prior to initiation of any part of the movement. Additional reaction time results related to initiation of longer responses are consistent with processing in terms of a sequence of indivisible motor gestalts. Some actions (e.g., many involving coordination of the hands) can be carried out effectively only if represented as a unitary gestalt. Second, a perceptual gestalt is independent of specific sensory receptors, as evidenced by perceptual constancy. In a similar manner a motor gestalt can be represented independently of specific muscular effectors, thereby allowing motor constancy. Third, just as a perceptual pattern (e.g., a Necker cube) is exclusively structured into only 1 of its possible configurations at any moment in time, processing prior to action is limited to 1 motor gestalt. Fourth, grouping in apparent motion leads to stream segregation in visual and auditory perception; this segregation is present in motor action and is dependent on the temporal rate. We discuss congruence of gestalt phenomena across perception and motor action (a) in relation to a unitary perceptual-motor code, (b) with respect to differences in the role of awareness, and (c) in conjunction with separate neural pathways for conscious perception and motor control.     

Problems in developing functional handwriting

The development of handwriting quality and speed of 407 primary school children was followed from Grade 1 to Grade 5 in a longitudinal experiment. Performance was analyzed to enquire into the extent and bases for handwriting dysfunction. 27% of the children were classified as dysfunctional at the end of Grade 1. At the end of Grade 5 only 13% were so classified. Most children have adequate perception and motor abilities to develop functional handwriting. Dysfunction of handwriting speed can usually be traced to dysfunction of its quality. Dysfunction of quality can be traced to insufficient individualization in the primary instruction in handwriting which leads to a mismatch between the time allocated to teach certain letters to certain children and the time required for these children to learn the form of these letters.     

A modern assessment of the basic forms of aphasia

A brief survey of the field of aphasia is presented. Many of the facts described in the neurological classics remain valid, but the interpretation of these facts must be altered. The basic principles of aphasia are reassessed in the light of neuropsychology. Neuropsychological analysis shows sensory (acoustico-gnostic) aphasia to be based upon an impairment in phonemic hearing. Motor aphasia breaks down into afferent (kinesthetic) and efferent (kinetic) aphasia. The former is based upon an impaired kinesthetic input into the speech functions, which results in a special type of oral apraxia. Efferent (kinetic) aphasia is based upon a breakdown in the kinetic organization of speech motor acts. Nominative (amnestic) aphasia consists of a number of forms, each based on either a weakness of visual or auditory analysis or difficulty in selection between evoked memory traces. “Transcortical motor aphasia” proves to be either perseverative aphasia, i.e., aphasia in which the dynamics of plasticity are impaired, or the result of the impairment of internal speech. The basic defect underlying “conduction” aphasia is beginning to be understood as a weakened acoustico-gnostic function or difficulties in retarding sideline associations.     

Model for a flexible motor memory based on a self-active recurrent neural network

Using recent recurrent network architecture based on the reservoir computing approach, we propose and numerically simulate a model that is focused on the aspects of a flexible motor memory for the storage of elementary movement patterns into the synaptic weights of a neural network, so that the patterns can be retrieved at any time by simple static commands. The resulting motor memory is flexible in that it is capable to continuously modulate the stored patterns. The modulation consists in an approximately linear inter- and extrapolation, generating a large space of possible movements that have not been learned before. A recurrent network of thousand neurons is trained in a manner that corresponds to a realistic exercising scenario, with experimentally measured muscular activations and with kinetic data representing proprioceptive feedback. The network is “self-active” in that it maintains recurrent flow of activation even in the absence of input, a feature that resembles the “resting-state activity” found in the human and animal brain. The model involves the concept of “neural outsourcing” which amounts to the permanent shifting of computational load from higher to lower-level neural structures, which might help to explain why humans are able to execute learned skills in a fluent and flexible manner without the need for attention to the details of the movement.     

The influence of motor function on processing speed in preterm and term-born children

This study investigates the relationship between motor function and processing speed in preterm children. Processing speed was compared in 145 adolescents, born 25–41 weeks gestational age, utilizing tasks including differing motor demands. The influence of motor cortex excitability and functional motor skills on task performance was assessed. For tasks with motoric demands, differences in performance between preterm and term-born children were mediated by the relationship between gestational age, corticomotor excitability, and motor function. There were no differences in non-motor processing speed task performance between preterm and term-born children. Measures of processing speed may be confounded by a timed motor component.     

Emergence of rhythm during motor learning

Complex motor skill often consists of a fixed sequence of movements. Recent studies show that a stereotyped temporal pattern or rhythm emerges as we learn to perform a motor sequence. This is because the sequence is reorganized during learning as serial chunks of movements in both a sequence-specific and subject-specific manner. On the basis of human imaging studies we propose that the formation of chunk patterns is controlled by the cerebellum, its posterior and anterior lobes contributing, respectively, to the temporal patterns before and after chunk formation. The motor rhythm can assist the motor networks in the cerebral cortex to control automatic movements within chunks and the cognitive networks to control non-automatic movements between chunks, respectively. In this way, organized motor skill can be performed automatically and flexibly.