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Results for “sensorimotor function”

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PubMed2001

The context of uncertainty modulates the subcortical response to predictability.

Implicit motor learning tasks typically involve comparisons of subject responses during a sequence versus a random condition. In neuroimaging, brain regions that are correlated with a sequence are described, but the temporal relationship of sequence versus nonsequence conditions is often not explored. We present a functional magnetic resonance imaging (fMRI) study describing activation related to sequential predictability in an implicit sensorimotor learning task and the history (context) dependence of these effects. Participants regarded four squares displayed horizontally across a screen and pressed a button when any one of the four targets was illuminated in a particular color. A repeating spatial sequence with varying levels of predictability was embedded within a random color presentation. Both the right dorsolateral prefrontal cortex (R DLPFC) and right caudate displayed a positive correlation to increasing predictability, whereas the left posterior parietal cortex (L PPC) displayed a negative correlation. However, the activation changes within the caudate were significant when transitioning from high predictability to low predictability but not for the reverse case, suggesting a sensitivity not only to predictability but to order effects as well. These results support the hypothesized relationship between basal ganglia and visuomotor sequential learning, but demonstrate the importance of context upon sequence learning.

Adult↗

PubMed2006

Regional gray matter volumetric changes in autism associated with social and repetitive behavior symptoms.

BACKGROUND: Although differences in brain anatomy in autism have been difficult to replicate using manual tracing methods, automated whole brain analyses have begun to find consistent differences in regions of the brain associated with the social cognitive processes that are often impaired in autism. We attempted to replicate these whole brain studies and to correlate regional volume changes with several autism symptom measures. METHODS: We performed MRI scans on 24 individuals diagnosed with DSM-IV autistic disorder and compared those to scans from 23 healthy comparison subjects matched on age. All participants were male. Whole brain, voxel-wise analyses of regional gray matter volume were conducted using voxel-based morphometry (VBM). RESULTS: Controlling for age and total gray matter volume, the volumes of the medial frontal gyri, left pre-central gyrus, right post-central gyrus, right fusiform gyrus, caudate nuclei and the left hippocampus were larger in the autism group relative to controls. Regions exhibiting smaller volumes in the autism group were observed exclusively in the cerebellum. Significant partial correlations were found between the volumes of the caudate nuclei, multiple frontal and temporal regions, the cerebellum and a measure of repetitive behaviors, controlling for total gray matter volume. Social and communication deficits in autism were also associated with caudate, cerebellar, and precuneus volumes, as well as with frontal and temporal lobe regional volumes. CONCLUSION: Gray matter enlargement was observed in areas that have been functionally identified as important in social-cognitive processes, such as the medial frontal gyri, sensorimotor cortex and middle temporal gyrus. Additionally, we have shown that VBM is sensitive to associations between social and repetitive behaviors and regional brain volumes in autism.

Adolescent↗

PubMed2001

[Hand motor cortical area reorganization following cerebral infarction evaluated with functional MRI, near infrared spectroscopic imaging, and transcranial magnetic stimulation].

A 60-year-old, right-handed man suffered from left hemiparesis with upper limb dominance. CT and MRI revealed cerebral infarction of the entire right middle cerebral artery territory. His hemiparesis recovered excellently and residual neurological deficits 6 years later were left hand weakness(grasping power 9 kg vs. 35 kg in the right) and clumsiness. Functional MRI was performed. During right(normal) hand grasping, activation was seen in the left sensorimotor cortex and supplementary motor area. During left(paretic) hand grasping, activation was seen in the left (ipsilateral) sensorimotor cortex, right parietal cortex, and bilateral supplementary motor areas. Near infrared spectroscopic imaging showed similar results. During right hand grasping, left sensorimotor cortex was activated, and during left hand grasping, bilateral sensorimotor cortices were activated with ipsilateral predominance. Transcranial magnetic stimulation of the left motor hand area evoked right hand movement and stimulation of a point near that area evoked ipsilateral left hand muscle movement. Thus, the findings of the three techniques consistently suggest that the recovery of left hemiparesis of this patient was promoted by motor cortical area reorganization including the ipsilateral motor cortex.

Brain↗

PubMed1977

Neuromuscular syndromes associated with malignant disease.

Malignant disorders may produce neuromuscular syndromes in a variety of ways, for some of which it is still difficult to determine the exact pathophysiology. In the myopathic and neuropathic disorders, one possible explanation is that they are due to a virus such as is found in the rare "progressive multifocal leukoencephalopathy". This is seen in association with the malignant lymphomas and with other conditions such as sarcoidosis where immune responses may be altered by either the disease or the treatment. No viral material has been found in the nonmetastatic neurological disorders apart from progressive multifocal leukoencephalopathy. An alternative theory is that there may be an autoimmune process, the nervous system sharing some antigenic determinant with the neoplasm (Urich, 1967). The prognosis in the paraneoplastic neurological disorders is usually poor. As well as the direct threat to life posed by the malignant disease, when the neurological disorder is due to destruction of neurones (for instance cerebellar degeneration or sensory neuronopathy) recovery of function is impossible. Spontaneous remissions have been recorded in cases of proximal muscle weakness and sensorimotor neuropathy, but it is difficult to know whether the remissions have been truly spontaneous or related to treatment (excision of the neoplasm or administration of steroids). Further immunological and virological studies will probably reveal the answers to some of the outstanding problems. In the meantime the clinician must continue to investigate patients with muscular weakness for evidence of an occult neoplasm, and to repeat investigations if no other cause for the neurological disorder is found. Also, in patients with known malignant disease, apart from trying to differentiate forms of neuromyopathy from the effects of metastases the various metabolic disorders must be considered because the therapeutic possibilities are a little more promising in the paraneoplastic endocrine disorders. Ross (1975) wisely said that "cancer has replaced syphilis as the great imitator".

Cachexia↗

PubMed1996

Regional difference in cerebral blood flow and oxidative metabolism in human cortex.

UNLABELLED: We sought to determine if there are regional differences in cerebral blood flow (CBF) and cerebral metabolic ratio for oxygen (CMRO2) in normal subjects during the resting state. METHODS: Regional CBF, CMRO2 and oxygen extraction fraction (OEF) in 15 normal volunteers (mean age 58.8 +/- 8.2 yr) were measured during rest using PET and a 15O-gas steady-state technique. RESULTS: CBF and CMRO2 in the visual cortex were significantly higher than those in other cortices. Additionally, OEF in the sensorimotor cortex was significantly lower than that in other cortical regions. CONCLUSION: CBF and CMRO2 in the visual cortex are always high, and low OEF in the sensorimotor cortex exists even in resting state in normal subjects. We hypothesize that these regional functional differences would result in different resistances to degeneration.

Brain↗

PubMed1998

[Driving fitness/driving capacity of patients treated with methadone].

To answer the question whether or not therapeutic methadone doses significantly reduce traffic-related performance of drivers on medically supervised methadone programmes, 34 methadone substitution patients, all of them volunteers, were subjected to a test series: the focus of the study was a psychophysical test battery consisting of 10 individual performance tests to assess essential functions with regard to driving ability, such as concentration, attention, reaction capability, memory, perception and sensorimotor coordination. In evaluating the results of the psychophysical tests, multiple drug use and subjective methadone influence at the time of the examination were taken into consideration but current methadone blood level was neglected. The results were compared to those of a control group. The methadone group (n = 34) consisted of 25 men and 9 women aged between 18 and 38. At the time of the study, the majority of the test persons (29) were on low dosage methadone maintenance (up to 60 mg/day). In the urine samples of approximately 2/3 of the test persons, evidence was found for multiple drug use together with other psychotropic substances, the most frequent (14) being cannabis metabolites. Referring to their driving practices, a mere 4 out of 29 drivers had not committed any driving offences. A comparison of the psychophysical performance of the whole methadone group (n = 34) with a control group demonstrated that the methadone substitution patients achieved rather lower results in almost all variables. These performance deficits were particularly conspicuous in sustained attention, sensorimotor coordination and reaction capability. 12 "methadone only" participants, i.e. methadone probands without any additional consumption of psychotropic substances showed-partly considerably-better performance than the methadone group as a whole and also achieved normal results in relation to the test norm. Nevertheless, once again, results tended to be of lower level in comparison to the control group. "Methadone only" substitution patients, in particular those volunteers without a current subjective methadone influence-reached practically the same results as the corresponding control subjects, or at least average results based on test norm. However, the study revealed distinctive performance impairment (e.g. in sustained attention, reaction capability) when other psychotropic substances (including alcohol and cannabis!) were taken as well during the subjective methadone phase. The performance deficits were predominantly caused by a slowing down of reactions. Our study illustrates that, under certain conditions, long-term methadone maintenance under strict medical supervision does not have any significant unfavourable impact on the psychophysical performances in driving ability as examined in this study. Thus, these research findings support the previous Zurich experiences, according to which driving ability--and in the end also driving aptitude--of the methadone substitution patients does not depend on the methadone therapy itself, nor on the amount of the daily methadone intake. In making the final medical judgement on driving ability, the presence of a mixed drug use and the personality of the person in question are of far greater importance.

Accidents, Traffic↗

PubMed2003

Functional reorganization of the motor cortex in adult rats after cortical lesion and treatment with monoclonal antibody IN-1.

We previously reported anatomical plasticity in the adult motor cortex after a unilateral sensorimotor cortex (SMC) lesion and treatment with monoclonal antibody (mAb) IN-1, which permits neurite outgrowth from the intact, opposite cortex into deafferented subcortical targets. This study was designed to investigate whether treatment with the mAb IN-1 after SMC lesion in the adult leads to functional reorganization of the intact, opposite motor cortex. Adult rats underwent unilateral SMC aspiration lesion and treatment with either mAb IN-1 or control antibody, or no treatment. After a 6 week survival period, the intact, opposite forelimb motor cortex was explored using intracortical microstimulation to evoke forelimb movements. A dramatic increase in ipsilateral movements of the lesion-impaired forelimb was found in animals treated with mAb IN-1 compared with control animals. These results resembled our previous findings of cortical reorganization in the spared hemisphere after neonatal cortical lesion and without any additional treatment. These results show that, after adult cortical lesion, treatment with mAb IN-1 induces a functional reorganization of the intact, opposite motor cortex.

Animals↗

PubMed1998

Cognitive neuroscience of human memory.

Current knowledge is summarized about long-term memory systems of the human brain, with memory systems defined as specific neural networks that support specific mnemonic processes. The summary integrates convergent evidence from neuropsychological studies of patients with brain lesions and from functional neuroimaging studies using positron emission tomography (PET) or functional magnetic resonance imaging (fMRI). Evidence is reviewed about the specific roles of hippocampal and parahippocampal regions, the amygdala, the basal ganglia, and various neocortical areas in declarative memory. Evidence is also reviewed about which brain regions mediate specific kinds of procedural memory, including sensorimotor, perceptual, and cognitive skill learning; perceptual and conceptual repetition priming; and several forms of conditioning. Findings are discussed in terms of the functional neural architecture of normal memory, age-related changes in memory performance, and neurological conditions that affect memory such as amnesia. Alzheimer's disease, Parkinson's disease, and Huntington's disease.

Amnesia↗

PubMedDate not supplied

Space vestibulo-neuroscience in the new century: why proceed in semi-darkness?

With advancing technology, neuroscientists have explored vestibular transducer microstructure and molecular processes, neural pathways of interaction between vestibular visual and proprioceptor systems and neurochemical processes of adaptive change. Progress in space vestibulo-neuroscience will be fostered by focus on interactions among the systems involved in whole-body movement relative to the earth. Description of perceptual and sensorimotor reactions to complex accelerative stimuli during goal-directed and passive movement is crucial to conceptualizing the functional significance of various interactions and viable theory. The vestibulo-ocular reflex is now quantifiable in three dimensions, but description of the dynamics of spatial orientation perception has progressed very little in the 20th century. Much is known about perception of static body tilt, but the dynamics of tilt and movement perception (beyond rotation about an earth-vertical axis) remains relatively unexplored. Innovative procedures and departure from accepted psychophysics are needed. Models developed to predict the dynamics of spatial orientation under complex conditions must be consistent with information at all levels (neural, sensorimotor, and perceptual). To close our eyes to any one aspect of the spatial orientation reaction is to proceed in semi-darkness unnecessarily.

Animals↗

PubMed2004

Coupling between "hand" primary sensorimotor cortex and lower limb muscles after ulnar nerve surgical transfer in paraplegia.

Previous neuroimaging evidence revealed an "invasion" of "hand" over "lower limb" primary sensorimotor cortex in paraplegic subjects, with the exception of a rare patient who received a surgical motor reinnervation of hip-thigh muscles by the ulnar nerve. Here, the authors show that a functional reorganization of cortico-muscular and cortico-cortical oscillatory coupling was related to the recovery of the rare patient, as a paradigmatic case of long-term plasticity in human sensorimotor cortex after motor reinnervation of paraplegic muscles. This conclusion was based on electroencephalographic and electromyographic data collected while the patient and normal control subjects performed isometric muscle contraction of the left hand or lower limb. Cortico-muscular and cortico-cortical coupling was estimated by electroencephalographic-electromyographic coherence and directed transfer function of a multivariate autoregressive model.

Adult↗

PubMed1990

Natural history of radiation-induced brachial plexopathy compared with surgically treated patients.

Twelve patients who developed radiation-induced brachial plexopathy (RIBP) after receiving radiation therapy for breast carcinoma (7 patients) or Hodgkin's lymphoma (5 patients) were followed for 12 or more years, with a mean follow-up time of 20 years. Tingling and numbness of the fingers as well as weakness of the hand or arm were the most prominent presenting symptoms of RIBP. Whereas pain in most patients evolved only later in the course, it became a predominant feature in only 2. In 8 of the 12 patients, the plexopathy was surgically treated, either by neurolysis only or by neurolysis plus omental grafting in order to stop progression or paresis and/or pain. In 8 patients, including 6 of the operated group, there was slow and steady progression of RIBP over time, with the final outcome being almost complete paralysis of the arm (2 patients) or severe sensorimotor paresis rendering the hand useless (6 patients). In only 4 patients, including 2 of the non-operated group, was there absence of progression and stabilization of the paresis with only slight functional loss of the affected arm in 3 patients and severe palsy in 1. None of the 12 patients had any clear long-lasting improvement of their sensorimotor impairment. It is concluded from this study that RIBP, irrespective of surgery (neurolysis and/or omentum transplant), left two-thirds of the patients with severe or total paresis of the arm. However, the almost complete relief of severe pain (6 of 8 patients), both immediately and in follow-up patients treated with neurolysis and/or omental transplant, indicates that surgical treatment has a beneficial effect on pain relief.

Adult↗

PubMed2005

The cerebral control of speech tempo: opposite relationship between speaking rate and BOLD signal changes at striatal and cerebellar structures.

So far, only sparse data on the cerebral organization of speech motor control are available. In order to further delineate the neural basis of articulatory functions, fMRI measurements were performed during self-paced syllable repetitions at six different frequencies (2-6 Hz). Bilateral hemodynamic main effects, calculated across all syllable rates considered, emerged within sensorimotor cortex, putamen, thalamus and cerebellum. At the level of the caudatum and the anterior insula, activation was found restricted to the left side. The computation of rate-to-response functions of the BOLD signal revealed a negative linear relationship between syllable frequency and response magnitude within the striatum whereas cortical areas and cerebellar hemispheres exhibited an opposite activation pattern. Dysarthric patients with basal ganglia disorders show unimpaired or even accelerated speaking rate whereas, in contrast, cerebellar dysfunctions give rise to slowed speech tempo which does not fall below a rate of about 3 Hz. The observed rate-to-response profiles of the BOLD signal thus might help to elucidate the pathophysiological mechanisms of dysarthric deficits in central motor disorders.

Acoustic Stimulation↗

PubMed2004

From superior adaptation and function to brain dysfunction--the neglect of epigenetic factors.

With optimal pregnancy conditions (natural, enriched diet which includes fish) African (Digo) infants are 3-4 weeks ahead of European/American infants in sensorimotor terms at birth, and during the first year. Infants of semi-aquatic sea-gypsies swim before they walk, and have superior visual acuity compared with us. With adverse pregnancy behaviour (fear of fat, a trend to dieting), neglecting the need for brain fat to secure normal brain development and function, we run a risk of dysfunction--death. Sudden Infant Death Syndrome victims have depressed birth weight, lower levels of marine fat in brainstem than controls, and >80 suffer multiple hypoxic episodes prior to death. Depressed birth weight (more than 10% below mean) is seen in learning and behaviour disorders, and a trend towards weights of less than 3kg is increasing, which supports a rise in antenatal sub optimality. Given marine fat deficiency in pregnancy and infancy, neurons starved for fuel could delay myelination and maturation in the latest developed Frontal Lobes. The phylogenetic oldest Lateral Frontal Lobe System (feed-back mechanism etc.) derived from olfactory bulb-amygdala, which crosses in Anterior Commisure is probably spared, while the Medial Frontal Lobe System derived from Hippocampus-Cingulum and crosses in Corpus Callosum (delayed response task) is most likely affected. The rise in infantile autism (intact vision and hearing) with deficit in delayed response task only, could suggest a deficit in the Medial Frontal Lobe System. The human species is unique; 70% of total energy to the foetus goes to development of the brain, which mainly consists of marine fat. It undergoes pervasive regressive events, before birth, in infancy and at puberty. Minimal retraction of neuronal arborisation is advantageous. Attributable to adverse pregnancy childrearing practice, excessive retraction is likely prenatally and in infancy. Pubertal age affects the fundamental property of nervous tissue, excitability: excessive excitatory drive is seen in early, and a deficiency in late puberty. It is postulated that with adequate marine fat, there is probably no risk of psychopathology at the extremes, whereas a deficiency could lead to paroxysmal (subcortical) dysfunction in early puberty, and breakdown of cortical circuitry and cognitive dysfunctions in late puberty. The post-pubertal psychoses, schizophrenia and manic-depressive psychosis at the extremes of the pubertal age continuum, with contrasting excitability and biological treatment, are probably the result of continuous dietary deficiency, which has inactivated the expression of genes for myelin development and oligodendrocyte-related genes in their production of myelin. The beneficial effect of marine fat in both disorders, in other CNS disorders as well as in developmental dyslexia (DD) and ADHD among others, supports our usual diet is persistently deficient. We have neglected the similarity of our great brain to other mammals, and our marine heritage. Given the amount of marine fat needed to secure normal brain development and function is not known, nor the present dietary level, it seems unduly conjectural to postulate that a dietary deficiency in marine fat is causing brain dysfunction and death. However, all observations point in the same direction: our diet focusing on protein mainly, is deficient, the deficiency is most pronounced in maternal nutrition and in infancy.

Adolescent↗

PubMed2003

Burst-induced synaptic depression and its modulation contribute to information transfer at Aplysia sensorimotor synapses: empirical and computational analyses.

The Aplysia sensorimotor synapse is a key site of plasticity for several simple forms of learning. Plasticity of this synapse has been extensively studied, albeit primarily with individual action potentials elicited at low frequencies. Yet, the mechanosensory neurons fire high-frequency bursts in response to even moderate tactile stimuli delivered to the skin. In the present study, we extend this analysis to show that sensory neurons also fire bursts in the range of 1-60 Hz in response to electrical stimuli similar to those used in behavioral studies of sensitization. Intracellular stimulation of sensory neurons to fire a burst of action potentials at 10 Hz for 1 sec led to significant homosynaptic depression of postsynaptic responses. The depression was transient and fully recovered within 10 min. During the burst, the steady-state depressed phase of the postsynaptic response, which was only 20% of the initial EPSP of the burst, still contributed to firing the motor neuron. To explore the functional contribution of transient homosynaptic depression to the response of the motor neuron, computer simulations of the sensorimotor synapse with and without depression were compared. Depression allowed the motor neuron to produce graded responses over a wide range of presynaptic input strength. In addition, enhancement of synaptic transmission throughout a burst increased motor neuron output substantially more than did preferential enhancement of the initial phase of a burst. Thus, synaptic depression increased the dynamic range of the sensorimotor synapse and can, in principle, have a profound effect on information processing.

Action Potentials↗

PubMed2005

Sensorimotor rhythm-based brain-computer interface (BCI): feature selection by regression improves performance.

People can learn to control electroencephalogram (EEG) features consisting of sensorimotor rhythm amplitudes and can use this control to move a cursor in one or two dimensions to a target on a screen. In the standard one-dimensional application, the cursor moves horizontally from left to right at a fixed rate while vertical cursor movement is continuously controlled by sensorimotor rhythm amplitude. The right edge of the screen is divided among 2-6 targets, and the user's goal is to control vertical cursor movement so that the cursor hits the correct target when it reaches the right edge. Up to the present, vertical cursor movement has been a linear function of amplitude in a specific frequency band [i.e., 8-12 Hz (mu) or 18-26 Hz (beta)] over left and/or right sensorimotor cortex. The present study evaluated the effect of controlling cursor movement with a weighted combination of these amplitudes in which the weights were determined by an regression algorithm on the basis of the user's past performance. Analyses of data obtained from a representative set of trained users indicated that weighted combinations of sensorimotor rhythm amplitudes could support cursor control significantly superior to that provided by a single feature. Inclusion of an interaction term further improved performance. Subsequent online testing of the regression algorithm confirmed the improved performance predicted by the offline analyses. The results demonstrate the substantial value for brain-computer interface applications of simple multivariate linear algorithms. In contrast to many classification algorithms, such linear algorithms can easily incorporate multiple signal features, can readily adapt to changes in the user's control of these features, and can accommodate additional targets without major modifications.

Adult↗

PubMed2000

Whole-brain functional MR imaging activation from a finger-tapping task examined with independent component analysis.

BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a priori assumptions about the hemodynamic response to the task. The purpose of this study was to analyze the temporal characteristics and the spatial mapping of the independent components identified by ICA when the subject performs a finger-tapping task. METHODS: Ten healthy subjects performed variations of the finger-tapping task conventionally used to map the sensorimotor cortex. The scan data were processed with ICA, and the temporal configuration of the components and their spatial localizations were studied. The locations with activation were tabulated and compared with locations known to be involved in the organization of motor functions in the brain. RESULTS: Components were identified that correlated to varying degrees with the conventional boxcar reference function. One or more of these components mapped to the sensorimotor cortex, supplementary motor area (SMA), putamen, and thalamus. By means of ICA components, sensorimotor cortex, supplementary motor area, and superior cerebellar activation were identified bilaterally in 100% of the subjects; thalamus activation was contralateral to the active hand in 80%; and putamen activation was contralateral to the active hand in 60%. CONCLUSION: ICA processing of multislice fMR imaging data acquired during finger tapping identifies the sensorimotor cortex, SMA, cerebellar, putamen, and thalamic activation. ICA appears to be a method that provides information on both the temporal and spatial characteristics of activation. Multiple task-related components can be identified by ICA, and specific activation maps can be derived from each separate component.

Brain↗

PubMed2003

Pathophysiology of tics and Tourette syndrome.

Tics are involuntary movements that can affect one or more muscles producing simple or complex movements. Blink reflex and startle reflex studies disclose an increased excitability of brainstem interneurons. Analysis of voluntary movement shows that when advance visual information is reduced, patients with tics and Tourette syndrome become progressively slower in completing motor sequences. Sensorimotor integration is abnormally processed. Studies of the contingent negative variation demonstrate abnormalities of movement preparation and the investigation of premotor potentials shows that in some patients tics are not preceded by a normal premotor potential. Magnetic stimulation studies demonstrate an increased excitability of cortical motor cortex. Functional MRI, PET and SPECT studies show abnormal activation of cortical and subcortical areas. Dysfunction of basal ganglia-thalamo-cortical projections affects sensorimotor, language and limbic cortical circuits, and may explain why patients with Tourette syndrome have difficulty in inhibiting unwanted behaviors and impulses.

Animals↗

PubMed2005

Arm function after stroke: from physiology to recovery.

There are varying degrees of spontaneous improvement in arm paresis over the first 6 months after stroke. The degree of improvement at 6 months is best predicted by the motor deficit at 1 month despite standard rehabilitative interventions in the ensuing 5 months. Animal studies indicate that the loss of fine motor control, especially individuation of the digits, is due to interruption of monosynaptic corticomotoneuronal connections. Spasticity occurs because of loss of cortical modulatory control on descending brain stem pathways and spinal segmental circuits but is not a major cause of motor dysfunction. Quantitative studies of reaching movements in patients suggest that arm paresis consists of higher-order motor planning and sensorimotor integration deficits that cannot be attributed to weakness or presence of synergies. Cortical stimulation experiments in animals and functional imaging studies in humans indicate that motor learning and recovery after stroke share common brain reorganization mechanisms. Rehabilitation techniques enhance learning-related changes after stroke and contribute to recovery. Future research will benefit from using quantitative methods to characterize the motor impairment after stroke and by applying concepts in motor learning to devise more physiologically based rehabilitation techniques.

Arm↗