PubMed Health⌕ Search

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 1,693 records · Page 94Linked to original sources
PubMed1994

Functional MR mapping of activated cortical areas.

Magnetic resonance imaging (MRI) has recently been demonstrated to be sensitive to changes in neuronal activity of cortical areas. We report our initial experiences with functional MR brain mapping at high spatial resolution using a conventional whole-body MR system. A total of 10 visual and motor cortex activation studies were carried out on 8 healthy volunteers. In each examination, a time course series of 15 strongly T2*-weighted FLASH images was measured from three adjacent slices. The image analysis revealed a subtle but highly significant signal increase in cortical layers of gray matter in primary and associative visual as well as sensorimotoric cortex regions during periods of excessive brain activity provoked by photic stimuli or motoric tasks, respectively. To correlate brain structure and brain function, the computed MR brain activation maps were directly superimposed on T1-weighted anatomic spin-echo images. With this advance into the area of functional neuroimaging, MRI is moving into an established domain of positron emission tomography (PET). We, therefore, discuss the advantages and limitations of the MR method in comparison to PET as far as this can be done at present.

Adult↗
PubMed1998

Engines, accelerators, and brakes on functional spinal cord repair.

It is proposed that four essential goals should be met for functional repair after traumatic injury of the adult spinal cord. These include protecting neural tissue after injury and limiting secondary cell damage; replacing lost tissue with transplanted cell "bridges"; blocking the expression of intrinsic factors within the adult CNS that inhibit neural repair; and providing appropriate sensorimotor activity to enhance plasticity within surviving circuits, as well as consolidate any anatomical repair/regeneration. Included is a brief discussion on the approaches and limitations in the evaluation of functional spinal cord repair.

Animals↗
PubMed2001

Different ipsilateral representations for distal and proximal movements in the sensorimotor cortex: activation and deactivation patterns.

Each hemisphere is known to be also involved in controlling the ipsilateral arm, but with an asymmetry favoring the dominant hemisphere. However, the relative role of primary and secondary motor areas in ipsilateral control is not well defined. We used whole brain functional magnetic resonance imaging in healthy human subjects to differentiate between contributions from primary and secondary areas during discrete unilateral distal finger and proximal shoulder movements. It was found that ipsilateral distal movements activated secondary areas only, while sparing or even significantly deactivating the primary sensorimotor cortex. Ipsilateral proximal movements substantially activated both SM1 and secondary areas. A newly defined small territory within the precentral gyrus, extending from the premotor cortex and intruding toward SM1, showed an activation pattern corresponding to secondary motor areas. Finally, the effects of hemispheric dominance were confirmed, but attributed exclusively to secondary areas. These new imaging findings agree well with functional requirements as well as established anatomical and neurophysiological data.

Adult↗
PubMed1977

Protein pattern alterations in hippocampal and cortical cells as a function of training in rats.

The study reports changes in the protein pattern and incorporation of L-[U-14C]-leucine in brain cells of the hippocampus and sensorimotor cortex of rats. The following subcellular fractions were analyzed by SDS-acrylamide gel electrophoresis: plasma membranes, synaptosomal membranes and synaptic mitochondria. Recurring reversal training gave an increased synthesis of synaptosomal membrane proteins with mol. wt. 35,000-45,000 and 60,000 and 100,000 in trained animals compared to active controls. Lesser changes were observed in plasma membrane and synaptic mitochondria fractions. Of the brain areas studied, the hippocampal synaptosomal fraction showed an initial, temporary response, and the cortical cell fractions responded subsequently. Judged from the time sequence of the protein response, it seems that recurrent reversal training induces a change in synaptic protein towards higher molecular weights, suggesting that these changes reflect a modification of the distribution of synaptic protein.

Animals↗
PubMed2003

Acute care physical therapist evaluation and intervention for an adult after right hemispherectomy.

BACKGROUND AND PURPOSE: Hemispherectomy is performed to help control intractable seizures, yet little research quantifies and projects the clinical course of the impairments, functional limitations, and disabilities of patients who have undergone the procedure. This case report describes the physical therapist preoperative and postoperative examination, evaluation, and intervention during the acute hospitalization of an adult who underwent a right hemispherectomy. CASE DESCRIPTION: The patient was a 27-year-old man who had intractable seizures despite having tried multiple drug regimens and undergoing several surgical interventions after a brain injury at age 5 years. He underwent a right functional hemispherectomy and then had 9 postoperative physical therapy sessions during his acute hospitalization. OUTCOMES: The patient made rapid gains, surpassing all initial goals. At discharge, the patient had distal left-sided sensorimotor impairments, but he was able to ambulate 121.9 m (400 ft) with assistance to maintain his balance. DISCUSSION: The patient's posthemispherectomy recovery was rapid. His brain injury at a young age may have triggered preoperative transfer of function to the unaffected left hemisphere. The prognosis for this patient's improvements of impairments and functional limitations was better than initially expected, perhaps because of the redundant features and plasticity of the central nervous system.

Adult↗
PubMed2006

Sensorimotor postural rearrangement after unilateral vestibular deafferentation in patients with acoustic neuroma.

Unilateral vestibular lesion, as acoustic neuroma and its surgical removal, leads to impaired balance control. After initial vertigo and postural instability corresponding to unilateral vestibular deafferentation, improvement in symptoms and global balance functions occurs by a process called vestibular compensation. In this respect, this prospective study aimed to assess the differential contribution of sensory inputs to the regulation of posture during the recovery process after acoustic neuroma removal. Twenty-seven patients with acoustic neuroma underwent vestibular and posturographic testings, shortly before and 8 days, 1 month and 3 months after surgical removal of the tumour. Immediately after vestibular deafferentation, vestibular function was asymmetrical, postural performances were altered, especially in eyes closed conditions and in sensory challenged situations. One month, and more particularly 3 months after surgery, restoration and even improvement of vestibular and balance performances occurred, associated with a lower number of falls, development of more appropriate sensorimotor strategies and better resolution of sensorial conflicts. Postural perturbations are related to erroneous vestibular afferences, leading to incoherence in information about head position and interference with somatosensory and visual pathways. The time-course implementation of central adaptive mechanisms, characterized by substitution by other sensory afferences and new behavioural strategies, leads to an improvement of balance performance.

Adult↗
PubMed2004

Reorganization in congenital hemiparesis acquired at different gestational ages.

It is well established that the reorganizational potential of the developing human brain is superior to that of the adult brain, but whether age-dependent differences exist already in the prenatal and perinatal period is not known. We have studied sensorimotor reorganization in 34 patients with congenital hemiparesis (age range, 5-27 years), using transcranial magnetic stimulation and functional magnetic resonance imaging during simple hand movements. Underlying pathologies were brain malformations (first and second trimester lesions; n = 10), periventricular brain lesions (early third trimester lesions; n = 12), and middle cerebral artery infarctions (late third trimester lesions; n = 12). Of this cohort, eight patients with malformations and all patients with periventricular lesions have been published previously. In all three groups of pathologies, transcranial magnetic stimulation identified patients in whom the paretic hand was controlled via ipsilateral corticospinal projections from the contralesional hemisphere (n = 16). In these patients, the motor dysfunction of the paretic hand correlated significantly with the timing period of the underlying brain lesion. This demonstrates that the efficacy of reorganization with ipsilateral corticospinal tracts indeed decreases during pregnancy.

Adolescent↗
PubMed1979

Topographical distribution of ATP in rat brain.

Studies on the distribution of ATP in microdissected segments of the rat brain indicate that the nucleotide is concentrated in gray matter, and especially in the thalamus, hippocampus, entorhinal cortex and sensorimotor cortex. These distribution studies in conjunction with previous neuropharmacological studies, support the concept that adenine nucleotides may function as intercellular mediators in various regions of the brain.

Adenosine Triphosphate↗
PubMed2005

[Recent insights into Rasmussen encephalitis].

Rasmussen encephalitis (RE) is a severe and at the same time pathophysiologically fascinating condition. The chronic inflammation affects one of the two cerebral hemispheres and destroys it during the disease process that lasts from months to years. The patients -- mostly children -- suffer from frequent pharmacoresistant seizures, often in the form of epilepsia partialis continua. In parallel to the atrophy of the affected hemisphere, the neurological functions associated with it decline continuously. This results in a final stage with a usually high-grade sensorimotor hemisyndrome, hemianopia, cognitive impairment and -- if the language-dominant hemisphere is affected -- aphasia. Research results in the last 5 years have contributed to a deeper understanding of the pathogenesis of this condition. Formal diagnostic criteria have been proposed, and new therapeutic options have emerged by which the disease progression can be slowed or stopped. This article summarizes the current research results on the background of older data and gives recommendations regarding diagnostic and therapeutic procedures in RE patients.

Clinical Trials as Topic↗
PubMed1992

Unilateral, but not bilateral, locus coeruleus lesions facilitate recovery from sensorimotor cortex injury.

This study investigates the role of the locus coeruleus in recovery from sensorimotor cortex injury. Unilateral locus coeruleus lesions given 2 weeks prior to unilateral sensorimotor cortex injury facilitate subsequent motor recovery compared to animals with only a sensorimotor cortex injury, while bilateral locus coeruleus lesions severely retard motor recovery. The results suggest that recovery of function from the cortical injury is facilitated as long as a sufficient amount of the noradrenergic system remains intact, perhaps to provide a basis for compensatory sprouting. The results also suggest that recovery does occur in the absence of the locus coeruleus, indicating that the noradrenergic system is not necessary for recovery to occur after the cortical injury.

Animals↗
PubMed1990

Hemispheric asymmetries in attentional control: implications for hand preference in sensorimotor tasks.

Liepmann (1908) proposed that handedness reflects the greater capacity of one hemisphere to learn the execution of skilled movements. Although asymmetries in motor control are an important basis for hand asymmetries, recent studies have suggested that handedness may be determined by multiple factors. In the present study, we examine how attentional asymmetries may contribute to hand preferences. Right-handed subjects participated in a reaction time task in which they were given preliminary information about where a target stimulus would occur (selective attention) or which hand to use for responding (selective intention). Our findings indicate that these processes influence each other reciprocally and favor a state of optimal attentional and intentional preparation of the right hand. We suggest that these hemispheric asymmetries in attentional control contribute to hand preferences in certain sensorimotor tasks.

Adult↗
PubMed2005

Integration of posture and movement: contributions of Sherrington, Hess, and Bernstein.

Neural mechanisms that integrate posture with movement are widespread throughout the central nervous system (CNS), and they are recruited in patterns that are both task- and context-dependent. Scientists from several countries who were born in the 19th century provided essential groundwork for these modern-day concepts. Here, the focus is on three of this group with each selected for a somewhat different reason. Charles Sherrington (1857-1952) had innumerable contributions that were certainly needed in the subsequent study of posture and movement: inhibition as an active coordinative mechanism, the functional anatomy of spinal cord-muscle connectivity, and helping set the stage for modern work on the sensorimotor cortex and the corticospinal tract. Sadly, however, by not championing the work of his trainee and collaborator, Thomas Graham Brown (1882-1965), he delayed progress on two key motor control mechanisms: central programming and pattern generation. Walter Hess (1881-1973), a self-taught experimentalist, is now best known for his work on CNS coordination of autonomic (visceral) and emotional behavior. His contributions to posture and movement, however, were also far-reaching: the coordination of eye movements and integration of goal-directed and "framework" (anticipatory set) motor behavior. Nikolai Bernstein (1896-1966), the quintessence of an interdisciplinary, self-taught movement neuroscientist, made far-reaching contributions that were barely recognized by Western workers prior to the 1960s. Today, he is widely praised for showing that the CNS's hierarchy of control mechanisms for posture and movement is organized hand-in-hand with distributed and parallel processing, with all three subject to evolutionary pressures. He also made important observations, like those of several previous workers, on the goal focus of voluntary movements. The contributions of Sherrington, Hess, and Bernstein are enduring. They prompt thought on the philosophical axioms that appear to have driven their research, and the continual need for emphasis on interdisciplinary, comparative, and transnational approaches to advance movement neuroscience.

Affect↗
PubMed1997

Persisting impairment following Rocky Mountain Spotted Fever: a case report.

A patient initially presented in the emergency room with fever, confusion, and a petechial rash. Rocky Mountain Spotted Fever (RMSF) was diagnosed and appropriate treatment was initiated. He subsequently became obtunded and required mechanical ventilation and temporary cardiac pacing. Four weeks later, he presented to our rehabilitation unit with ataxia, hyperreflexia and upper motor neuron signs, dysesthesias, sensorimotor axonopathy demonstrated by electrodiagnostic studies, and a global decrement in cognitive capability. Although he significantly improved in functional mobility and self-care, he exhibited little improvement in his cognitive impairment at 6-month follow-up. An understanding of the natural history of, and long-term impairments associated with, RMSF will be helpful to physiatrists in developing rehabilitation care plans and in assisting such patients with community re-entry.

Activities of Daily Living↗
PubMed1998

Step cycle-related oscillatory properties of inferior olivary neurons recorded in ensembles.

This study was conducted to characterize patterns of discharge from the dorsal accessory olive during different behavioural states. To accomplish this goal, adult rats were chronically implanted with arrays of microwires (25-50 microns) to record from as many as 23 neurons from the dorsal accessory olive bilaterally during locomotor paradigms or at rest. Olivary neurons discharged sporadically at low firing frequencies (1-5 Hz) when the rat was at rest. However, during locomotor paradigms involving constant speed treadmill locomotion, olivary neurons discharged rhythmically at frequencies which closely matched step cycle frequencies. The rhythmic nature of olivary discharge was maintained even during brief periods of inconsistent gait. During treadmill locomotion utilizing variable acceleration/deceleration paradigms olivary neurons discharged at 3 Hz frequencies. Electrical stimulation of peripheral afferents resulted in rhythmic discharge of olivary neurons at frequencies harmonic with the rate of stimulation. These data suggest that oscillatory patterns of discharge exhibited by the inferior olivary nucleus are only seen during rhythmic behavioral tasks or stimulation paradigms. Further, the dissociation between the rhythmic nature of the task and the continued oscillation suggests that oscillatory activity of the inferior olive may be due both to an intrinsic rhythm as well as related to ongoing sensorimotor input.

Animals↗
PubMed1997

Cholinesterase inhibition improves blood flow in the ischemic cerebral cortex.

The ability of central cholinesterase inhibition to improve cerebral blood flow in the ischemic brain was tested in Sprague-Dawley rats with tandem occlusion of left middle cerebral and common carotid arteries. Cerebral blood flow was measured with lodo- 14C-antipyrine autoradiography in 170 regions of cerebral cortex. The regional distribution of blood flow was characterized in normal animals by cerebral blood flow maxima in the temporal regions. After 2 h ischemia, minimum cerebral blood flow values were found in the lateral frontal and parietal areas on the left hemisphere, and a new maximum was found in the right hemisphere in an area approximately symmetrical to the ischemic focus. Heptyl-physostigmine (eptastigmine), a carbamate cholinesterase inhibitor with prolonged time of action improved cerebral blood flow in most regions, with the exception of the ischemic core. The drug also enhanced the ischemia-induced rostral shift of cerebral blood flow maxima in the right hemisphere. The effects of eptastigmine were more marked 24 h after ischemia. Discriminant analysis showed that data from only 22 regions was sufficient to achieve 100% accuracy in classifying all cases into the various experimental conditions. The redistribution of cerebral blood flow to the sensorimotor area of the right hemisphere of animals with cerebral ischemia, a phenomenon possibly related to recovery of function, was also enhanced by eptastigmine.

Animals↗
PubMed1998

Influence of somatosensory input on paroxysmal activity in benign rolandic epilepsy with 'extreme somatosensory evoked potentials'.

We studied six patients suffering from benign rolandic epilepsy of childhood with central temporal spikes who presented so-called 'extreme somatosensory evoked potentials (SEPs)' following peripheral somatosensory stimulation. Stimuli were delivered to the fingers of one hand using both a triggered tendon hammer and low-intensity electrical stimulation. The electrical stimulation was delivered in sequences in different conditions (i.e. random order, 1, 3 and 10 Hz). Both tapping and electrical stimulation produced scalp evoked potentials in all subjects, characterized by a spike followed by a slow wave, similar in morphology and scalp distribution to the spontaneously occurring spikes. This paroxysmal activity was sensitive to stimulus rate; the number of evoked spikes was inversely related to the frequency of stimulation, being maximal at 1 Hz and disappearing at high frequencies (10 Hz). Spontaneous spikes disappeared during high-frequency stimulation but were present during low-frequency stimulation. Averaged SEPs at 3-Hz stimulation showed a late high-amplitude component, identical in morphology and distribution to the single evoked spike. We therefore conclude that, in these subjects, the so-called 'extreme SEPs' are evoked spikes and that evoked and spontaneous spikes share common cortical sensorimotor generators. The evidence that these generators can be influenced by afferent input provides important information regarding the functional mechanisms involved in modulating cortical excitability in benign rolandic epilepsy. Moreover, we suggest that peripheral electrical stimulation can be used as an additional activation test in this kind of epilepsy.

Age of Onset↗
PubMed2003

Cerebral reorganisation of human hand movement following dynamic immobilisation.

Surgical treatment of a flexor tendon lesion of the hand is followed by a 6-week period of dynamic immobilisation. This is achieved by the elastic strings of a Kleinert splint, enabling only passive and no active flexor movements. After such immobilisation, the appearance of a temporary clumsy hand indicates decreased efficiency of cerebral motor control. Using PET we identified the recruitment of contralateral parietal and cingulate activations specifically related to the suboptimal character of these hand movements. After 6-8 weeks, normalised movement was related with contralateral putamen activation. Activations of the sensorimotor cortex and cerebellum were present during both scanning sessions. Changes in the pattern of cerebral activations reflect functional reorganisation. The shift from cortical to striatal involvement, observed in the group of four patients, generates the concept of unlearned movements being relearned.

Cerebellum↗