SEARCH · PubMed Health

Results for “sensorimotor function”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources

PubMed2004

Optimizing the experimental design for ankle dorsiflexion fMRI.

Compared to motor studies of the upper limb, few experiments have sought a relationship between blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) sensorimotor signals and the resulting lower limb output. In Experiment 1, using an fMRI simulator system, we determined the optimized experimental protocol based on two design types and four behavioral movement types during ankle dorsiflexion. Experiment 2 involved testing the BOLD sensitivity at 1.5 T during ankle movements. Subjects performed large- and small-amplitude dorsiflexion movement types using an event-related design, with the intent of contrasting spatial and temporal features of the BOLD signal. In both experiments, the subject's behavior was guided by visual biofeedback of their ankle flexion angle, using an MR-compatible fiberoptic tape. From Experiment 1, we found electromyography (EMG) difference voltage ratio of approximately 2:1 for large (40 degrees ) and small (15 degrees ) dorsiflexion, 0.13 mV and 0.07 mV, respectively. In Experimental 2, we found the peak BOLD % signal changes of 1.04% and 0.89%, for large (40 degrees ) and small (15 degrees ) dorsiflexion, respectively. In addition, graded dorsiflexion produced graded BOLD signals in the primary sensorimotor and supplementary motor areas in 10 of 12 healthy young subjects, attesting to the feasibility of lower-limb fMRI at 1.5 T. This study provides insight into the cortical network involved in dorsiflexion using an experimental paradigm that is likely to translate effectively to hemiparetic stroke subjects.

Adult↗

PubMed2001

Parsing cognition in schizophrenia using saccadic eye movements: a selective overview.

Eye movements provide a behavioural measure of sensorimotor processing and higher cognitive functions of the brain. With the development of novel paradigms that can be used for the study of various cognitive operations, saccadic eye movements in particular, have become increasingly popular. Patients with schizophrenia have neurocognitive impairments that can be readily investigated with these paradigms. From animal, human lesion and neuroimaging studies, the cerebral centres underlying saccadic eye movements have been identified. The areas of the prefrontal cortex include the dorsolateral prefrontal cortex, the frontal eye fields, the supplementary eye fields, and the anterior cingulate cortex. Pathology of saccadic eye movements, therefore, provides information on the functional status of the underlying neural circuitry in brain disorders such as schizophrenia. In this paper, we evaluate: (i) methodological considerations that are central to the design and application of saccadic paradigms; (ii) brain activation that is associated with saccadic paradigms; (iii) recent findings in healthy subjects and schizophrenic patients; (iv) saccadic abnormalities in other psychiatric and neurological disorders and in individuals at risk for developing schizophrenia.

Animals↗

PubMed2000

Balance control and posture differences in the anxious BALB/cByJ mice compared to the non anxious C57BL/6J mice.

A relation between anxiety disorders and balance control dysfunctions has been observed in many studies in humans. A mismatch in the integration of sensory inputs could trigger these disturbances. Very few experimental animal procedures have been designed to study the functional link between anxiety and balance control. A task was therefore developed, challenging the visual, vestibular and somesthesic sensory systems in mice. The test, called the 'rotating beam', gave an accurate assessment of balance control and the posture, using sensitive measures (number of falls and imbalances, position of tail and trunk). Striking differences were observed between the two inbred strains of mice known to have radically different anxiety-related behaviour. The highly anxious strain, BALB/cByJ, performed poorly compared to the non anxious strain, C57BL/6J. Balance control and postural abilities of anxious mice were improved by acute anxiolytic diazepam treatment. Lower behavioural performance level was registered in non anxious mice given anxiogenic beta-CCM treatment. The findings account for a strong relationship between anxiety and balance control in mice. Finally, the highly sensitive procedure proved to be well suited to the study of functional links between anxiety and sensorimotor processes.

Animals↗

PubMed1997

Slow eye movements.

Monkeys and humans are able to perform different types of slow eye movements. The analysis of the eye movement parameters, as well as the investigation of the neuronal activity underlying the execution of slow eye movements, offer an excellent opportunity to study higher brain functions such as motion processing, sensorimotor integration, and predictive mechanisms as well as neuronal plasticity and motor learning. As an example, since there exists a tight connection between the execution of slow eye movements and the processing of any kind of motion, these eye movements can be used as a biological, behavioural probe for the neuronal processing of motion. Global visual motion elicits optokinetic nystagmus, acting as a visual gaze stabilization system. The underlying neuronal substrate consists mainly of the cortico-pretecto-olivo-cerebellar pathway. Additionally, another gaze stabilization system depends on the vestibular input known as the vestibulo-ocular reflex. The interactions between the visual and vestibular stabilization system are essential to fulfil the plasticity of the vestibulo-ocular reflex representing a simple form of learning. Local visual motion is a necessary prerequisite for the execution of smooth pursuit eye movements which depend on the cortico-pontino-cerebellar pathway. In the wake of saccades, short-latency eye movements can be elicited by brief movements of the visual scene. Finally, eye movements directed to objects in different planes of depth consist of slow movements also. Although there is some overlap in the neuronal substrates underlying these different types of slow eye movements, there are brain areas whose activity can be associated exclusively with the execution of a special type of slow eye movement.

Animals↗

PubMed1999

Induction of c-Fos-like protein in bulbar catecholaminergic neurones by electrical stimulation of the sensorimotor cortex in the rat.

The sensorimotor cortex (SMC) establishes a functional connectivity with the nucleus tractus solitarius (NTS) and the rostral ventrolateral medulla (RVLM). These bulbar nuclei are known to contain catecholaminergic neurones involved in the cardiovascular control. The aim of the present study was to establish the proportion of catecholaminergic neurones activated by electrical stimulation of SMC. For this purpose, double immunocytochemical procedures were used to reveal the distribution of Fos protein and tyrosine hydroxylase (TH). The results showed that, in the NTS, 7% of the neurones immunoreactive for TH expressed Fos-protein, versus 34% in the RVLM. These data provide evidence that the SMC activated preferentially catecholaminergic neurones of the RVLM which are known to be involved in cardiovascular control via spinal preganglionic neurones.

Animals↗

PubMed2006

Postural orientation and equilibrium: what do we need to know about neural control of balance to prevent falls?

Postural control is no longer considered simply a summation of static reflexes but, rather, a complex skill based on the interaction of dynamic sensorimotor processes. The two main functional goals of postural behaviour are postural orientation and postural equilibrium. Postural orientation involves the active alignment of the trunk and head with respect to gravity, support surfaces, the visual surround and internal references. Sensory information from somatosensory, vestibular and visual systems is integrated, and the relative weights placed on each of these inputs are dependent on the goals of the movement task and the environmental context. Postural equilibrium involves the coordination of movement strategies to stabilise the centre of body mass during both self-initiated and externally triggered disturbances of stability. The specific response strategy selected depends not only on the characteristics of the external postural displacement but also on the individual's expectations, goals and prior experience. Anticipatory postural adjustments, prior to voluntary limb movement, serve to maintain postural stability by compensating for destabilising forces associated with moving a limb. The amount of cognitive processing required for postural control depends both on the complexity of the postural task and on the capability of the subject's postural control system. The control of posture involves many different underlying physiological systems that can be affected by pathology or sub-clinical constraints. Damage to any of the underlying systems will result in different, context-specific instabilities. The effective rehabilitation of balance to improve mobility and to prevent falls requires a better understanding of the multiple mechanisms underlying postural control.

Accidental Falls↗

PubMed2002

A prospective study of motor recovery following multiple subpial transections.

A prospective study of motor recovery was undertaken in a patient scheduled to undergo multiple subpial transections (MST) of right sensorimotor cortex. Pre-transection, functional MRI (fMRI) and cortical stimulation mapping confirmed left hand motor control within right primary motor cortex. Immediately post-transection, behavioral testing demonstrated preserved strength bilaterally but decreased dexterity in the left hand. Seven weeks post-transection, dexterity returned to normal and left hand finger tapping corresponded with multiple bilateral foci of fMRI activation. At 16 weeks, fMRI activation returned to pre-transection levels. These data indicate that cortical injury due to MST resulted in the temporary recruitment of distant cortical sites which presumably subserved normal motor function during recovery.

Adult↗

PubMed2006

Cerebellar synaptic defects and abnormal motor behavior in mice lacking alpha- and beta-dystrobrevin.

The dystrobrevins (alphaDB and betaDB) bind directly to dystrophin and are components of a transmembrane dystrophin-glycoprotein complex (DGC) that links the cytoskeleton to extracellular proteins in many tissues. We show here that alphaDB, betaDB, and dystrophin are all concentrated at a discrete subset of inhibitory synapses on the somata and dendrites of cerebellar Purkinje cells. Dystrophin is depleted from these synapses in mice lacking both alphaDB and betaDB, and DBs are depleted from these synapses in mice lacking dystrophin. In dystrophin mutants and alphaDB,betaDB double mutants, the size and number of GABA receptor clusters are decreased at cerebellar inhibitory synapses, and sensorimotor behaviors that reflect cerebellar function are perturbed. Synaptic and behavioral abnormalities are minimal in mice lacking either alphaDB or betaDB. Together, our results show that the DGC is required for proper maturation and function of a subset of inhibitory synapses, that DB is a key component of this DGC, and that interference with this DGC leads to behavioral abnormalities. We suggest that motor deficits in muscular dystrophy patients, which are their cardinal symptoms, may reflect not only peripheral derangements but also CNS defects.

Animals↗

PubMed1987

Activity: occupational therapy's treatment method. 1987 Eleanor Clarke Slagle lecture.

A philosophical framework to explain the value of using activity as a treatment method is the challenge pursued for this lectureship. Primary resources came from Soviet psychology, the only social science discipline using the concept of activity as a focus of study. The focus of study selected for occupational therapy is disability, which is explained within the context of doing an activity. The patient's purpose for doing an activity is described by the degree of sensorimotor thought processed during a functional state. A hierarchy of activity analysis is used to begin the development of typologies for feasible operations, satisfactory results, and desirable activities. The philosophical framework is applied to three types of patient populations that pose problems in stating treatment objectives, patients that have (a) a good prognosis but one that is associated with alternative explanations for change, (b) a poor prognosis associated with a lifelong disability, and (c) a grave prognosis associated with a progressive loss of functional abilities. A refined treatment hypothesis is suggested: Therapeutic activity compensates for disability by using remaining capabilities to accomplish desirable activities with satisfactory results.

Accident Prevention↗

PubMed2002

A double dissociation within striatum between serial reaction time and radial maze delayed nonmatching performance in rats.

Lesions involving the intralaminar thalamic nuclei have been associated with impairments in working memory and intentional motor function in human clinical cases and animal models of amnesia. The intralaminar nuclei have afferent and efferent connections related to striatum. To test whether disruption of striatal function can account for impairments produced by intralaminar lesions, we investigated the effects of striatal lesions on two tasks known to be impaired by intralaminar damage in the rat: radial maze delayed nonmatching (DNM), a measure of spatial working memory, and self-paced serial reaction time (SRT), a measure of intentional response speed. We compared the effects of lesions in four sites: the medial and lateral caudate putamen, nucleus accumbens, and olfactory tubercle. We found that lesions of the medial, accumbens, or tubercle sites impaired DNM performance, and that lesions of the lateral caudate putamen increased choice response time for the SRT task. There was a double dissociation between the effects of the ventral and the lateral lesions on these two tasks. For both tasks, the effects of striatal lesions were qualitatively similar and at least as large as intralaminar lesions in previous studies. These results provide evidence that striatal dysfunction can account for the DNM and SRT impairments produced by intralaminar lesions. The dissociation of functional impairments suggests that lateral sensorimotor areas of caudate putamen are important for responding based on external sensory stimuli and limbic-related areas in ventral striatum are important for responding based on information held in working memory.

Animals↗

PubMed1999

Ephrin-A binding and EphA receptor expression delineate the matrix compartment of the striatum.

The striatum integrates limbic and neocortical inputs to regulate sensorimotor and psychomotor behaviors. This function is dependent on the segregation of striatal projection neurons into anatomical and functional components, such as the striosome and matrix compartments. In the present study the association of ephrin-A cell surface ligands and EphA receptor tyrosine kinases (RTKs) with the organization of these compartments was determined in postnatal rats. Ephrin-A1 and ephrin-A4 selectively bind to EphA receptors on neurons restricted to the matrix compartment. Binding is absent from the striosomes, which were identified by mu-opioid receptor immunostaining. In contrast, ephrin-A2, ephrin-A3, and ephrin-A5 exhibit a different mosaic binding pattern that appears to define a subset of matrix neurons. In situ hybridization for EphA RTKs reveals that the two different ligand binding patterns strictly match the mRNA expression patterns of EphA4 and EphA7. Ligand-receptor binding assays indicate that ephrin-A1 and ephrin-A4 selectively bind EphA4 but not EphA7 in the lysates of striatal tissue. Conversely, ephrin-A2, ephrin-A3, and ephrin-A5 bind EphA7 but not EphA4. These observations implicate selective interactions between ephrin-A molecules and EphA RTKs as potential mechanisms for regulating the compartmental organization of the striatum.

Animals↗

PubMed2000

Disturbed functional brain interactions underlying deficient tactile object discrimination in Parkinson's disease.

Somatosensory discrimination of cuboid objects was studied in a group of healthy volunteers and patients with Parkinson's disease using regional cerebral blood flow (rCBF) measurements obtained with positron emission tomography (PET) and 15O labeled water [H2 15O]. A 6-[18F]-fluoro-L-dopa (FDOPA) PET scan demonstrated that the patients may be grouped into those with normal and those with abnormally lowA FDOPA uptake in the caudate nucleus. The categorical group comparisons revealed that task-induced rCBF increases were deficient in bilateral motor and sensory cortical areas in the Parkinson patients. Moreover, deficient rCBF increases were evident in the mesial and right dorsolateral prefrontal cortex for patients in a more advanced disease state, who showed low FDOPA uptake in the caudate nucleus. A principal component analysis (PCA), performed on the rCBF data, identified three patterns (principal components, PCs) that differentiated patients from normals. The first PC represented a right-hemisphere dominant, bilateral group of brain areas known to be involved in tactile exploration. A second PC reflected a cortical-subcortical pattern of functional interactions, comprising cortical areas important for working memory processes. The third group-differentiating PC revealed a pattern of functional interactions involving bilateral temporo-parieto-occipital association cortices, which was consistent with a hypothesized supramodal network necessary for object discrimination. In an additional subgroup analysis, greater expression of the third PC pattern predicted greater caudate FDOPA uptake in patients. Our neuroimaging data revealed a disturbance of distinct patterns of brain functional interactions related to the sensorimotor deficit in Parkinson's disease and to deficits of cognitive information processing deficits in the more advanced stage of Parkinson's disease.

Adult↗

PubMed2002

Doppler ultrasonography in tinnitus patients.

Tinnitus can be functionally measured and localized through sensorimotor and neurosensory tests. According to our Neurofisiología Otooftalmológica data bank, 60% of patients requiring a consultation have a history of cardiocirculatory disorders. This figure has moved us to study cerebrovascular processes in those patients seeking consultation for a tinnitus symptom only. The sudden appearance of the tinnitus symptom alone independent of patient age, leads us to consider a pathology of vascular origin, which should be evaluated and treated immediately. A mistake or delay in the diagnosis could cause the symptom to become chronic, owing to the appearance of microlesions at any level of the auditory pathway, as has been demonstrated in former investigations.

Adult↗

PubMed1988

[Use of psychophysiologic indices for the prognosis of the clinical action of tranquilizers].

A comprehensive comparative approach was used to assess the effectiveness of the psychophysiological indices as predictors of the effect of tranquilizing therapy with benzodiazepine drugs in neurotic patients. The study resulted in selection of several psychophysiological characteristics most relevant to the prognosis of individual responses to the tranquilizers irrespective of the particular neurosis form. The characteristics are recommended for the routine medical use. Indices of the sensorimotor activity and visual analyzer functional lability are among these.

Adult↗

PubMed1983

[Dual organization of sensorimotor activity].

An anatomical symmetry of the bilateral organism and the functional assignment of brain hemispheres each to one side of the body are preconditions for sensorimotor brain localization. The invariant system elements necessary for this consist of "modules". These are associations of about 2 500 cortical cells in each case. When we refer to duality, we do not mean dualistically separated, but mutually assigned or mutually coordinated half-systems. The mainly decussated sensory and nervous systems of the vertebrates probably give rise to their rhythmic gait coordinated in relation to the axis of the body. Compared to such vital movements, human motor activity varies between voluntary action and involuntary expression. Cortical projection duplicates in the form of secondary or supplementary sensorimotor areas are ascribed hypothetically to an identifiable somatosensory sensation. A development leading to man is likely to have commenced as the brain halves of a pithecanthropus gained asymmetric degrees of freedom in relation to their somatotopic binding to the body. This phylogenetic differentiation led to a dual disjunction of the cerebral hemispheres which enabled a side-different "either/or" in human actions. Speech and thought as transitive order forms are also based on functional asymmetries of the human cerebrum.

Cerebral Cortex↗

PubMed2004

Sensorimotor gating deficits in transgenic mice expressing a constitutively active form of Gs alpha.

Schizophrenia is a complex disorder characterized by wide-ranging cognitive impairments, including deficits in learning as well as sensory gating. The causes of schizophrenia are unknown, but alterations in intracellular G-protein signaling pathways are among the molecular changes documented in patients with schizophrenia. Using the CaMKIIalpha promoter to drive expression in neurons within the forebrain, we have developed transgenic mice that express a constitutively active form of G(s)alpha (G(s)alpha(*)), the G protein that couples receptors such as the D(1) and D(5) dopamine receptors to adenylyl cyclase. We have also generated mice in which the CaMKIIalpha promoter drives expression of a dominant-negative form of protein kinase A, R(AB). Here, we examine startle responses and prepulse inhibition of the startle reflex (PPI) in these G(s)alpha(*) and R(AB) transgenic mice. G(s)alpha(*) transgenic mice exhibited selective deficits in PPI, without exhibiting alterations in the startle response, whereas no deficit in startle or PPI was found in the R(AB) transgenic mice. Thus, overstimulation of the cAMP/PKA pathway disrupts PPI, but the cAMP/PKA pathway may not be essential for sensorimotor gating. G(s)alpha(*) transgenic mice may provide an animal model of certain endophenotypes of schizophrenia, because of the similarities between them and patients with schizophrenia in G-protein function, hippocampus-dependent learning, and sensorimotor gating.

Acoustic Stimulation↗

PubMed1986

Recovery of function after neonatal or adult hemispherectomy in cats: I. Time course, movement, posture and sensorimotor tests.

Cats with removal of the left hemitelencephalon (hemispherectomy) as neonates (n = 12) or in adulthood (n = 14), were compared using a battery of 16 neurological and behavioral tests given when they were young adults (kittens) or at least 5 months after the lesion (adults). The neonatal-lesioned subjects grew normally and performed markedly and significantly better than adult-lesioned cats in 13 tests covering the wide range of movement, posture and sensory functions which were assessed. None of the animals recovered tactile placing of the right forelimb or a normal vision in the right visual field. However, the overall recovery was outstanding for all cats such that the neonatal-lesioned were hard to differentiate from intact controls in their spontaneous, daily activities. Because the lesions were similar in the two age-at-lesion groups, and since numerous functions were followed for prolonged, comparable postlesion time, we conclude that, after hemispherectomy in the cat, there definitely is greater functional recovery if the lesion is sustained early in life. We propose that the enhanced recovery of function in neonatal-lesioned cats is largely due to the extensive anatomical reorganization which we have demonstrated in ongoing studies, and which contrasts with a lesser remodeling in adult-lesioned cats.

Age Factors↗

PubMed1999

Disrupted allocentric but preserved egocentric spatial learning in transgenic mice with impaired glucocorticoid receptor function.

Spatial and non-spatial learning of mice with an incorporated antisense RNA complementary to a fragment of cDNA coding for the glucocorticoid receptor (GR) were evaluated in allocentric and egocentric radial maze and water maze tasks, and in spontaneous object recognition and sensorimotor learning paradigms. Mice with impaired GR function did not acquire two maze paradigms based on allocentric spatial navigation, radial maze non-matching to position and water maze spatial discrimination learning. Comparison of performance in spaced and massed trials indicated that this may be due to a general inability to store information into allocentric reference memory or in retrieval processes. However, both groups of animals learned the rules of an egocentric radial maze task at similar rates and there was no difference in their ability to recognise objects once animals had equal opportunity to explore the sample objects. Sensorimotor performance was impaired in transgenic animals, but it is suggested that this is due to non-specific factors rather than to disrupted sensorimotor learning per se. These results are consistent with a disruption of hippocampal function. Histological examination of the hippocampus revealed no obvious structural abnormalities in transgenic animals. Therefore, the data suggest that functional underactivity of GRs at the level of the hippocampus induces a deficit in allocentric navigation while sparing egocentric navigation and object recognition.

Animals↗