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Motor Behaviour (motor + behaviour)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	43%

Selected Abstracts

1-Hz repetitive TMS over ipsilateral motor cortex influences the performance of sequential finger movements of different complexity

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2008
Laura Avanzino
Abstract To elucidate the role of ipsilateral motor cortex (M1) in the control of unilateral finger movements (UFMs) in humans we used a conditioning protocol of 1-Hz repetitive transcranial magnetic stimulation (1-Hz rTMS) over M1 in 11 right-handed healthy subjects. We analysed the effects of conditioning rTMS on UFMs of different complexity (simple vs sequential finger movements), and performed with a different modality (internally vs externally paced movements). UFMs were monitored with a sensor-engineered glove, and a quantitative evaluation of the following parameters was performed: touch duration (TD); inter-tapping interval (ITI); timing error (TE); and number of errors (NE). 1-Hz rTMS over ipsilateral M1 was able to affect the performance of a sequence of finger opposition movements in a metronome-paced condition, significantly increasing TD and reducing ITI without TE changes. The effects on motor behaviour had a different magnitude as a function of the sequence complexity. Further, we found a different effect of the ipsilateral 1-Hz rTMS on externally paced movements with respect to an internally paced condition. All these findings indicate that ipsilateral M1 plays an important role in the execution of sequential UFMs. Interestingly, NE did not change in any experimental condition, suggesting that ipsilateral M1 influences only the temporal and not the spatial accuracy of UFMs. Finally, the duration (up to 30 min) of 1-Hz rTMS effects on ipsilateral M1 can indicate its direct action on the mechanisms of cortical plasticity, suggesting that rTMS can be used to modulate the communication between the two hemispheres in rehabilitative protocols. [source]

Computational motor control: feedback and accuracy

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2008
Emmanuel Guigon
Abstract Speed/accuracy trade-off is a ubiquitous phenomenon in motor behaviour, which has been ascribed to the presence of signal-dependent noise (SDN) in motor commands. Although this explanation can provide a quantitative account of many aspects of motor variability, including Fitts' law, the fact that this law is frequently violated, e.g. during the acquisition of new motor skills, remains unexplained. Here, we describe a principled approach to the influence of noise on motor behaviour, in which motor variability results from the interplay between sensory and motor execution noises in an optimal feedback-controlled system. In this framework, we first show that Fitts' law arises due to signal-dependent motor noise (SDNm) when sensory (proprioceptive) noise is low, e.g. under visual feedback. Then we show that the terminal variability of non-visually guided movement can be explained by the presence of signal-dependent proprioceptive noise. Finally, we show that movement accuracy can be controlled by opposite changes in signal-dependent sensory (SDNs) and SDNm, a phenomenon that could be ascribed to muscular co-contraction. As the model also explains kinematics, kinetics, muscular and neural characteristics of reaching movements, it provides a unified framework to address motor variability. [source]

Discharge patterns of neurons in the medial pontobulbar reticular formation during fictive mastication in the rabbit

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2001
K.-G. Westberg
Abstract In this study, we describe functional characteristics of neurons forming networks generating oral ingestive motor behaviours. Neurons in medial reticular nuclei on the right side of the brainstem between the trigeminal and hypoglossal motor nuclei were recorded in anaesthetized and paralysed rabbits during two types of masticatory-like motor patterns induced by electrical stimulation of the left (contralateral) or right (ipsilateral) cortical masticatory areas. Sixty-seven neurons in nucleus reticularis pontis caudalis (nPontc), nucleus reticularis parvocellularis (nParv), and nucleus reticularis gigantocellularis (Rgc) were studied. These were classified as phasic or tonic depending on their firing pattern during the fictive jaw movement cycle. Phasic neurons located in the dorsal part of nPontc were active during the jaw opening phase, whilst those in dorsal nParv tended to fire during the closing phase. In most neurons, burst duration and firing frequency changed between the two motor patterns, but there was little change in phase of firing. Tonic units were mainly recorded in the ventral half of nPontc, and at the junction between Rgc and caudal nParv. Cortical inputs with short latency from the contralateral masticatory area were more frequent in phasic (82%) than tonic (44%) neurons, whilst inputs from the ipsilateral cortex were equal in the two subgroups (57% and 56%). Phasic neurons had significantly shorter mean contralateral than ipsilateral cortical latencies, whilst there was no difference among tonic neurons. Intra- and perioral primary afferent inputs activated both types of neurons at oligo-synaptic latencies. Our results show that subpopulations of neurons in medial reticular nuclei extending from the caudal part of the trigeminal motor nucleus to the rostral third of the hypoglossal motor nucleus are active during the fictive masticatory motor behaviour. Unlike masticatory neurons in the lateral tegmentum, the medial subpopulations are spatially organized according to discharge pattern. [source]

Investigation of dopamine receptors in susceptibility to behavioural and psychological symptoms in Alzheimer's disease

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 9 2009
Antonia L. Pritchard
Abstract Objective Alzheimer's disease (AD) patients commonly suffer from behavioural and psychological symptoms of dementia (BPSD). A genetic component to the development of BPSD in AD has been supported. Polymorphisms within dopamine receptors DRD1, DRD2, DRD3 and DRD4 have previously been investigated in a few interesting studies that are reviewed here and extended using our patient cohort. Methods Our large cohort of 395 probable AD patients had longitudinal information on the BPSD (Neuropsychiatric Inventory), which was used to dichotomise patients into whether they had ever suffered from a given symptom within the study period, or not. These measures were related to the DRD1 (A-48G), DRD2 (ser311cys; C-ins/del), DRD3 (ser9gly) and DRD4 (VNTR) genotype and allele frequencies. Results Associations were revealed between DRD3 and elation, and between DRD4 with agitation/aggression and with depression; however, these findings do not remain significant after correction for multiple testing. No associations were found with the other genetic variants and these symptoms and no associations were observed between any of the polymorphic variants examined and delusions, hallucinations, psychosis and aberrant motor behaviour. Conclusion Our data, in combination with a review of the literature, reveal a potential role for the VNTR variant of DRD4 in the development of depression in AD patients. The findings presented here need to be replicated in large, well characterised longitudinal cohorts. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The course of neuropsychiatric symptoms in dementia.

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 6 2005
Part I: findings from the two-year longitudinal Maasbed study
Abstract Background Although neuropsychiatric symptoms in dementia are common, there have been few large long-term prospective studies assessing the course of a broad range of neuropsychiatric symptoms in dementia. Objectives To investigate the course of neuropsychiatric symptoms in patients with dementia, including data about prevalence, incidence and persistence. Methods One hundred and ninety-nine patients with dementia were assessed every six months for two-years, using the Neuropsychiatric Inventory (NPI) to evaluate neuropsychiatric symptoms. Results Nearly all patients (95%) developed one or more neuropsychiatric symptoms in the two-year study period. Mood disorders were the most common problem. The severity of depression decreased, whereas the severity of apathy and aberrant motor behaviour increased during follow-up. The cumulative incidence was highest for hyperactive behaviours and apathy. Overall behavioral problems were relatively persistent, but most symptoms were intermittent, with apathy and aberrant motor behaviour being persistent for longer consecutive periods. Conclusions Neuropsychiatric symptoms in dementia are a common and major problem. Different symptoms have their own specific course, most of the time show a intermittent course, but behavioural problems overall are chronically present. The data have implications for developing treatment strategies. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Behavioural and psychological syndromes in Alzheimer's disease

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 11 2004
A. Mirakhur
Abstract Objectives The origins of behavioural and psychological symptoms of dementia are still poorly understood. By focusing on piecemeal behaviours as opposed to more robust syndrome change valid biological correlates may be overlooked. Our understanding of BPSD via the identification of neuropsychiatric syndromes. Methods We recruited 435 subjects from old age psychiatry and elderly care memory outpatient clinics fulfilling the criteria for diagnosis of probable Alzheimer's disease. Behavioural and psychological symptoms were assessed using the Neuropsychiatric Inventory. Principal components factor analysis was carried out on the composite scores of the 12 symptom domains to identify behavioural syndromes (factors). Results were confirmed by performing three different rotations: Varimax, Equamax and Quartimax. Results Four factors were identified (which accounted for 57% of the variance): ,affect' factor,depression/dysphoria, anxiety, irritability/lability and agitation/aggression; ,physical behaviour' factor,apathy, aberrant motor behaviour, sleep disturbance and appetite/eating disturbance; ,psychosis' factor,delusions and hallucinations; ,hypomania' factor,disinhibition and elation/euphoria. These groups were unchanged when different methods of rotation were used. Conclusions We report novel observations that agitation/aggression/irritability cluster within a depressive symptom factor and apathy is found within a physical behaviour factor. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Mesencephalic human neural progenitor cells transplanted into the neonatal hemiparkinsonian rat striatum differentiate into neurons and improve motor behaviour

JOURNAL OF ANATOMY, Issue 6 2006
Marine Hovakimyan
Abstract Neural stem cell transplantation is a promising strategy for the treatment of neurodegenerative diseases. To evaluate the differentiation potential of human neural progenitor cells (hNPCs) as a prerequisite for clinical trials, we intracerebrally transplanted in vitro expanded fetal mesencephalic hNPCs into hemiparkinsonian rats. On postnatal day one (P1), 17 animals underwent a unilateral intraventricular 6-hydroxydopamine injection into the right lateral ventricle. At P3, animals (n = 10) received about 100 000 hNPCs (1 µL) in the right striatum. Five weeks after birth, animals underwent behaviour tests prior to fixation, followed by immunohistochemistry on brain slices for human nuclei, glial fibrillary acidic protein, S100,, neuronal nuclei antigen, neuron-specific enolase and tyrosine hydroxylase. Compared with the apomorphine-induced rotations in the lesioned-only group (7.4 ± 0.5 min,1), lesioned and successfully transplanted animals (0.3 ± 0.1 min,1) showed a significant therapeutic improvement. Additionally, in the cylinder test, the lesioned-only animals preferred to use the ipsilateral forepaw. Conversely, the lesioned and transplanted animals showed no significant side bias similar to untreated control animals. Transplanted human nuclei-immunoreactive cells were found to survive and migrate up to 2000 µm into the host parenchyma, many containing the pan-neuronal markers neuronal nuclei antigen and neuron-specific enolase. In the striatum, tyrosine hydroxylase-immunoreactive somata were also found, indicating a dopaminergic differentiation capacity of transplanted hNPCs in vivo. However, the relative number of tyrosine hydroxylase-immunoreactive neurons in vivo seemed to be lower than in corresponding in vitro differentiation. To minimize donor tissue necessary for transplantation, further investigations will aim to enhance dopaminergic differentiation of transplanted cells in vivo. [source]

Neuropsychiatric interpretations of postencephalitic movement disorders

MOVEMENT DISORDERS, Issue 6 2003
Christopher D. Ward MD
Abstract This study reviews the impact of encephalitis lethargica (EL) on concepts of behaviour and movement during the 1920s and 1930s. Clinicopathological correlations were imprecise but supported the role of subcortical structures in complex patterns of motor behaviour. This possibility challenged the widely assumed hegemony of the cerebral cortex. There was a perceived link between involuntary movements and reduced impulse control and also between parkinsonism and a defect in volition. Contemporary observers interpreted postencephalitic phenomena such as oculogyria in psychodynamic as well as in neurophysiological terms. EL also gave some support to the idea that neuroses such as obsessional neurosis and hysteria might have an organic basis. These speculations recently have acquired more credibility. The large amount of literature on EL and its sequelae could perhaps make further contributions to understanding the pathology of voluntary movement and action. © 2003 Movement Disorder Society [source]

Dystonia: A disorder of motor programming or motor execution?

MOVEMENT DISORDERS, Issue 6 2002
Petr Ka, ovský MD
Abstract For some time, dystonia has been seen as purely a motor disorder. Relatively novel concepts published approximately 10 years ago also presumed that in the development of dystonic dyskinesias, only motor behaviour was abnormal. Neurophysiological observations of various types of dystonic disorders, which were performed using sophisticated electromyography, polymyography, H-reflex examination, long-latency reflex, etc., as well as new insights into the behaviour of dystonia, have urged the inclusion of sensory (particularly somatosensory) mechanisms into the pathophysiological background of dystonia. The major role has been considered to be played by abnormal proprioceptive input by means of the Ia proprioceptive afferents, with the source of this abnormality found in the abnormal processing of muscle spindle afferent information. However, neurophysiological investigations have also provided evidence that the abnormality in the central nervous system is located not only at the spinal and subcortical level, but also at the cortical level; specifically, the cortical excitability and intracortical inhibition have been revealed as abnormal. This evidence was revealed by SEP recordings, paired transcranial magnetic stimulation recordings, and BP and CNV recordings. The current concept of dystonic movement connects the abnormal function of somatosensory pathways and somatosensory analysers with the dystonic performance of motor action, which is based on the abnormality of sensorimotor integration. © 2002 Movement Disorder Society [source]

Emotions in action through the looking glass,

THE JOURNAL OF ANALYTICAL PSYCHOLOGY, Issue 1 2010
Corrado Sinigaglia
Abstract:, The paper aims at highlighting how our primary understanding of others' actions is rooted in the mirror mechanism. To this end, the anatomical architecture of the mirror neuron system for action will be outlined as well as its role in grasping goals and intentions in others' motor behaviour. One further step through the looking glass of social cognition will be referring to the ubiquitous emotional colouring of actions and considering its links with the motor domain. This will allow a clearer perspective on the mechanism underlying our abilities for emotional understanding and on cases in which these abilities are amiss, as in autistic spectrum disorders. Translations of Abstract Cet article vise à mettre l'accent sur la manière dont notre compréhension primaire des actions d'autrui s'enracine dans le mécanisme du miroir. A ces fins, sera esquissée l'architecture anatomique du système neuronal de l'action, de même que son rôle dans la saisie des buts et intentions du comportement moteur de l'autre. Un pas supplémentaire à travers le miroir réfléchissant de la cognition sociale et sera abordée la question de la coloration émotionnelle inhérente aux actions et de ses liens avec le domaine moteur. Ceci nous fournira une perspective plus claire du mécanisme sous-tendant nos aptitudes à la compréhension émotionnelle, notamment dans les cas où de telles aptitudes font défaut, à savoir les troubles de la sphère de l'autisme. Der Text beleuchtet, wie unser primäres Verstehen des Handelns anderer im Spiegelmechanismus wurzelt. Hierzu wird die anatomische Architektur des Spiegelneuronensystems nachgezeichnet sowie dessen Rolle beim Erfassen von Zielen und Absichten aus dem motorischen Verhalten anderer. Ein weiterer Blick durch die Brille sozialen Erkennens richtet sich auf die ubiquitäre emotionale Färbung von Handlungen sowie deren Verbindung zur Domäne des Motorischen. Dieses ermöglicht eine deutliche Perspektive auf die Mechanismen, die unseren Fähigkeiten zu sozialem Verstehen zugrundeliegen wie auch auf die Fälle, in denen diese Fähigkeiten fehlen, wie etwa in den Störungen des Formenkreises des Autismus. Questo lavoro si propone di mettere in luce in che modo la comprensione primaria delle azioni degli altri si radichi nel meccanismo del rispecchiamento. A questo scopo verrà delineata l'architettura anatomica per l'azione del sistema dei neuroni specchio oltre al suo ruolo nell'afferrare le mete e le intenzioni nel comportamento motorio degli altri. Un ulteriore passo attraverso lo specchio della conoscenza sociale sarà il riferimento alla colorazione emotiva dotata di ubiquità delle azioni e il considerare i suoi legami con il campo motorio. Ciò permetterà una prospettiva più chiara del meccanismo sottostante le nostre capacità di comprensione emotiva e della sua assenza in certi casi, come nei disturbi dello spettro autistico. El objetivo de este trabajo en destacar cómo nuestra comprensión primaria de las acciones de otros están arraigadas en el mecanismo de espejo. A este fin, será resumida la arquitectura anatómica del sistema de neuronas de espejo para la acción así como su papel para logar los objetivos e intenciones en la conducta motriz de otros. Un paso adicional en el espejo de la cognición social se refiere al ubicuo colorido emocional de acciones teniendo en cuenta sus lazos con el dominio motriz. Esto permitirá una perspectiva más clara en los mecanismo fundamentales de nuestras capacidades para la comprensión emocional y en casos en los que estas capacidades están dañadas, como en el espectro los desórdenes autistas. [source]

Inconvenient Truths about neural processing in primary motor cortex

THE JOURNAL OF PHYSIOLOGY, Issue 5 2008
Stephen H. Scott
Primary motor cortex (MI) plays an important role in voluntary motor behaviour, yet considerable debate remains on how neural processing within this brain region contributes to motor function. This article provides a brief review of the dominant conceptual frameworks used to interpret MI activity, notably servo-control during the 1970s and early 1980s, and sensorimotor transformations since that time. The former emphasized the use of feedback, but was abandoned because delays in sensory feedback could not permit sufficient feedback gains to generate observed patterns of limb movement. The latter framework focuses attention on identifying what coordinate frames, or representations, best describe neural processing in MI. However, studies have shown that MI activity correlates with a broad range of parameters of motor performance from spatial target location, hand or joint motion, joint torque and muscle activation patterns. Further, these representations can change across behaviours, such as from posture to movement. What do heterogeneous, labile neural representations mean and how do they help us understand how MI is involved in volitional motor control? Perhaps what is required is a new conceptual framework that re-focuses the experimental problem back on processes of control. Specifically, optimal feedback control has been proposed as a theory of the volitional motor system and it is argued here that it provides a rich, new perspective for addressing the role of MI and other brain regions in volitional motor control. [source]

Development of adaptive motor behaviour in typically developing infants

ACTA PAEDIATRICA, Issue 4 2010
KR Heineman
Abstract Aim:, During motor development, infants learn to select adaptive motor strategies out of their motor repertoire. The aim of this study is twofold: first, to investigate whether the presence of adaptive motor behaviour can be observed reliably, and second, to explore the ages at which clinically observable transition to adaptive motility emerges for four specific motor functions: abdominal progression, sitting motility, reaching and grasping. Methods:, The reliability part of the study included 38 assessments of term and preterm infants in the age range of 4,18 months. The longitudinal prospective study included 30 term born typically developing infants with nine assessments between 3 and 18 months. On the basis of standardized video-recordings of spontaneous motor behaviour, the presence of adaptive motor strategies was scored. Results:, Intra- and interobserver reliability were good. Clinically observable transitions to adaptive selection started to emerge from 6 months onwards and peaked between 8 and 15 months. Transitions developed gradually and occurred at specific ages for different motor functions. Conclusion:, Transition to adaptive motor behaviour can be observed reliably. Adaptive motor behaviour develops gradually from 6 months onwards at function-specific ages. Comparison of our results to literature showed that changes measured by neurophysiologic methods precede clinically observed transitions. [source]

Behavioural correlates of early-treated congenital hypothyroidism

ACTA PAEDIATRICA, Issue 10 2001
L Kooistra
Parents' and teachers' ratings were used to evaluate the behavioural characteristics of children with early-treated congenital hypothyroidism (CH). Comparisons were made between 63 children with early-treated CH and 34 healthy controls at the ages of 7.5 and 9.5 y. Additional comparisons were made between the two largest CH subgroups (thyroid agenesis, thyroid dysgenesis) and controls. The most marked differences were found on the introversion cluster and the motor clumsiness scale within it. Children with CH, particularly those with thyroid agenesis, showed introversion and motor clumsiness rather than social negativity and inattention. It is suggested that this behavioural profile may well have its origins in the often-reported inefficient motor behaviour of these children. Results are discussed in the light of recent findings suggesting an association between thyroid hormone problems and attention deficit hyperactivity disorder. Conclusion: Early-treated CH is associated with introversion rather than with social negativity. [source]

Control of eye orientation: where does the brain's role end and the muscle's begin?

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2004
Dora E. Angelaki
Abstract Our understanding of how the brain controls eye movements has benefited enormously from the comparison of neuronal activity with eye movements and the quantification of these relationships with mathematical models. Although these early studies focused on horizontal and vertical eye movements, recent behavioural and modelling studies have illustrated the importance, but also the complexity, of extending previous conclusions to the problems of controlling eye and head orientation in three dimensions (3-D). An important facet in understanding 3-D eye orientation and movement has been the discovery of mobile, soft-tissue sheaths or ,pulleys' in the orbit which might influence the pulling direction of extraocular muscles. Appropriately placed pulleys could generate the eye-position-dependent tilt of the ocular rotation axes which are characteristic for eye movements which follow Listing's law. Based on such pulley models of the oculomotor plant it has recently been proposed that a simple two-dimensional (2-D) neural controller would be sufficient to generate correct 3-D eye orientation and movement. In contrast to this apparent simplification in oculomotor control, multiple behavioural observations suggest that the visuo-motor transformations, as well as the premotor circuitry for saccades, pursuit eye movements and the vestibulo-ocular reflexes, must include a neural controller which operates in 3-D, even when considering an eye plant with pulleys. This review summarizes the most recent work and ideas on this controversy. In addition, by proposing directly testable hypotheses, we point out that, in analogy to the previously successful steps towards elucidating the neural control of horizontal eye movements, we need a quantitative characterization first of motoneuron and next of premotor neuron properties in 3-D before we can succeed in gaining further insight into the neural control of 3-D motor behaviours. [source]