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Results for “sensorimotor function”

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PubMed1997

Magnetoencephalographic mapping: basic of a new functional risk profile in the selection of patients with cortical brain lesions.

OBJECTIVE: Surgical management of cortical lesions adjacent to or within the eloquent cerebral cortex requires a critical risk: benefit analysis of the procedure before intervention. This study introduced a measure of surgical risk, based on preoperative magnetoencephalographic (MEG) sensory and motor mapping, and tested its value in predicting surgical morbidity. METHODS: Forty patients (21 men and 19 women; mean age, 36.5 yr) with cortical lesions (12 arteriovenous malformations and 28 tumors) in the vicinity of the sensorimotor cortex were classified into high-, medium-, or low-risk categories by using the MEG-defined functional risk profile (FRP). This was based on the minimal distance between the lesion margin and the sensory and motor MEG sources, superimposed on a magnetic resonance imaging scan. Case management decisions were based on the MEG mapping-derived FRP in combination with biopsy pathological findings, radiographic findings, and anatomic characteristics of the lesion. A recently developed protocol was used to transform MEG source locations into the stereotactic coordinate system. This procedure provided intraoperative access to MEG data in combination with stereotactic anatomic data displays routinely available on-line during surgery. RESULTS: It was determined that 11 patients diagnosed as having gliomas had high FRPs. The margin of the lesion was less than 4 mm from the nearest MEG dipole or involved the central sulcus directly. A nonoperative approach was used for six patients of this group, based on the MEG mapping-derived FRP. In the group with arteriovenous malformations, 6 of 12 patients with high or medium FRPs underwent nonoperative therapy. The remaining 28 patients, whose lesions showed satisfactory FRPs, underwent uneventful lesion resection, without postoperative neurological deficits. CONCLUSION: Our results suggest that MEG mapping-derived FRPs can serve as powerful tools for use in presurgical planning and during surgery.

Adult↗

PubMed2004

HMG-CoA reductase inhibitor, atorvastatin, promotes sensorimotor recovery, suppressing acute inflammatory reaction after experimental intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Statins have neuroprotective effects on ischemic stroke. They modify the endothelial function, increase blood flow, and inhibit thrombus formation, which are independent of lipid-lowering effects. However, whether statins have a protective effect toward hemorrhagic stroke is yet unknown. To test this possibility, we attempted to determine the effect of atorvastatin on experimental intracerebral hemorrhage (ICH). METHODS: ICH was induced using stereotaxic infusion of collagenase into the left basal ganglia in adult rats. Atorvastatin (1 mg/kg or 10 mg/kg) or phosphate-buffered saline was administered for 2 weeks. To monitor the sensorimotor deficits, limb placing and Rotorod tests were performed. Hematoma volume, brain water content, and hemispheric atrophy were analyzed. Immunohistochemical staining for myeloperoxidase (MPO), microglia (OX42), inducible nitric oxide synthase (iNOS), or endothelial nitric oxide synthase (eNOS) was performed. Perihematomal cell death was determined by TUNEL staining. RESULTS: The atorvastatin-treated ICH group showed better performance on Rotorod and limb placing tests when compared with the vehicle-treated group (P<0.01). The hematoma volumes between groups were not different, but the brain water content and hemispheric atrophy were reduced in the atorvastatin-treated ICH group. Atorvastatin reduced TUNEL-positive cells, iNOS expression, and MPO-positive or OX42-positive cells in the perihematomal regions in a dose-dependent manner, whereas it increased eNOS expression. CONCLUSIONS: The present study shows that atorvastatin reduces the perihematomal cell death via antiinflammation, which is associated with sensorimotor recovery after experimental ICH.

Animals↗

PubMed1992

[Behavioral asymmetry in BALB/cCF mice with corpus callosum abnormalities].

The possible homology between anomalies of the corpus callosum in mice and in humans remains questionable. The small number of existing behavioural studies in mice have not shown effects, at the behavioural level, of the absence or reduction in size of the corpus callosum. We therefore examined the development, during the first 3 weeks of postnatal life, of a number of simple reflex and integrative responses in the members of a sample of 101 BALB/cCF mice; at autopsy carried out at 50 days of age, 29 mice showed anomalies of the corpus callosum (total absence or an area less than 0.75 mm2). Asymmetry of the development of these responses was measured either as the proportion of animals showing asymmetrical appearance of responses on the left and right sides, and as the delay between appearances on the left and right sides in "asymmetrical" mice. Both measures decreased over the first 15 postnatal days, at the same rate in normal and abnormal mice; in each case the decrease is better described by a second-order, quadratic, function than by a simple linear function. We therefore conclude that the integrity of the corpus callosum is not necessary for the normal maturation of sensorimotor behaviour in mice, and suggest that this conclusion may possibly be explained by the relatively recent appearance of mice in the mammalian radiation.

Agenesis of Corpus Callosum↗

PubMed1998

Motor and somatosensory deficits following uni- and bilateral lesions of the cortex induced by aspiration or thermocoagulation in the adult rat.

We have previously shown that lesions of the sensorimotor cortex induced by either thermocoagulation or aspiration produce different effects on axonal plasticity. We have now investigated whether these methods of lesion also influence the behavioral outcome. The behavioral effects of unilateral and bilateral lesions of the sensorimotor cortex induced by either aspiration or by thermocoagulation of pial blood vessels were examined in adult Sprague-Dawley rats. Rats were tested to determine limb use asymmetry by analyzing (1) coordinated forelimb placement and (2) paw use preference when rearing. Their responsiveness to somatosensory stimulation was tested by analyzing (1) the latency to remove sticky tape on the ventral surface of the paw, and (2) vibrissae-stimulated forelimb placing. Behavioral tests were performed prior to surgery and on day 4, 8, 12, 16, and 20 after surgery. Both unilateral lesions resulted in an over-reliance on the nonimpaired forelimb as early as 4 days after the surgery; functional recovery occurred after 16 days. Animals with bilateral lesions did not use either forelimb for support in postural support behaviors. However, this effect was more apparent in the animals with a thermocoagulatory lesion and, in contrast to the animals with an aspiration lesion, these animals did not show functional recovery. Animals with a unilateral aspiration, but not a thermocoagulatory lesion, showed a slowed response to tactile stimulation applied to the contralateral forelimb. After bilateral lesions, animals showed a slowed response to tactile stimulation applied to either forelimb at early time points after the lesion and recovery of function at later time points. These data indicate that, for the most part, lesions of the sensorimotor cortex by aspiration or thermocoagulation produce very similar effects on the behaviors examined in this study. However, unexpectedly, thermocoagulatory lesions induced a more severe (unilateral lesion) or prolonged (bilateral lesion) deficit in forelimb use than aspiration lesions. Conversely, the effect on tactile stimulation is more prominent after unilateral aspiration than thermocoagulatory lesions.

Animals↗

PubMedDate not supplied

Psychological prognosis of diagnosed chronic organic solvent intoxication.

The psychological prognosis of 86 patients (40 men and 46 women) with previously diagnosed chronic solvent intoxication due to trichloroethylene, perchloroethylene, or solvent mixtures was studied after a follow-up period (mean 5.9 years). The patients' mean age at the time of diagnosis was 38.6 years, and the mean duration of solvent exposure was 10.7 years. Tests for intelligence, short-term memory, and sensory and motor functions were applied. The group means of the patients' intellectual functions were increased after the follow-up period. At the group level, the scores on one sensorimotor task and tasks requiring manual dexterity were lower. Individual patients performed better, worse, or equally when the results of the initial examination and the reexamination were compared. The overall prognosis of psychological test results was better with a longer follow-up period and lower age. Patients who used drugs with neurological effects had a poorer overall psychological prognosis. The characteristic of solvent exposure were related only to the prognosis of some single tests for sensory and motor functions.

Adult↗

PubMed1978

A behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in Macaca mulatta.

Ten Macaca mulatta monkeys were operantly conditioned to perform three motor paradigms designed to evaluate single and combination finger movements. Eight of these monkeys were retested after left medullary pyramidotomy; 2 monkeys underwent left medullary pyramidotomy prior to conditioning. All animals were tested for three years after operation. Monkeys with a completely sectioned medullary pyramid could, with time, perform difficult motor paradigms that required: (1) both individual and combination finger movements; (2) proximal upper extremity motor control; (3) thumb and index finger pincer grasp; and (4) the ability to preprogram and then execute a precision hand movement. The greater the extent of pyramidal tract destruction, the longer the time necessary for recovery of both discrete finger movement and pincer grasp, the greater the effort needed to attain recovery of hand function, and the weaker the affected musculature. The 2 animals in which pyramidotomy of at least 70% of the tract preceded efforts at operant conditioning learned and performed difficult motor paradigms. In all animals, neurological examination revealed that the most enduring and functionally most important deficit that interferes with hand function following pyramidotomy is loss of contactual hand orienting responses and failure of reflex sensorimotor adjustments.

Animals↗

PubMed1983

The 'M2' electromyographic response to random perturbations of arm movements is missing in long-trained monkeys.

Adult monkeys who have been under training over a long period of time show a loss of the M2 component in their biceps electromyographic response to brief, random perturbations of an alternating arm movement, the M1 component being apparently enhanced. These changes of the stretch-induced responses indicate a long-term plasticity of the sensorimotor system of monkeys. This result also provides hints for the origin and possible functional significance of the short- and long-latency components of the electromyographic response in subjects with less experience.

Animals↗

PubMed2005

Retrograde study of hypocretin-1 (orexin-A) projections to subdivisions of the dorsal raphe nucleus in the rat.

A retrograde tracer, WGA-apo-HRP-gold (WG), was injected into each subdivision of the dorsal raphe (DR) nucleus, and subsequent orexin-A immunostaining was performed for the tuberal region of the hypothalamus in order to investigate orexin projections to the DR. Similar to previous studies, the majority of orexin-single-labeled neurons were observed at the dorsal half of the lateral hypothalamus (LH), the circle around the fornix, i.e., perifornical nucleus (PeF), and the area dorsal to the fornix. The present study reports that hypothalamic neurons exhibited differential projections to each subdivision of the DR. Following WG injections into rostral DR, WG-single-labeled cells were observed at the dorsal half of the LH as well as dorsomedial hypothalamic nucleus. The major input to the intermediate DR originates from the ventromedial portion of the LH, PeF, and the area dorsal to the PeF, whereas one to lateral wing DR derived from PeF as well as the ventrolateral portion of the LH. Following WG injections into caudal DR, WG-single-labeled cells were located at ventromedial LH and the ventrolateral portion of the posterior hypothalamus. Following WG injections into each DR subdivision, WG/orexin-double-labeled neurons were observed at LH, PeF, and the area dorsal to the PeF. Only a few double-labeled cells were observed in dorsomedial and posterior hypothalamic nuclei. Our observations suggest that various hypothalamic neurons differentially project to each subdivision of the DR, a portion of which is orexin-immunoreactive. These orexin-immunoreactive DR-projecting hypothalamic neurons might have wake-related influences over a variety of brain functions subject to DR efferent regulation, including affective behavior, autonomic control, nociception, cognition, and sensorimotor integration.

Animals↗

PubMed2006

Effect of hindlimb suspension on activation and MHC content of triceps brachii and on the representation of forepaw on the sensorimotor cortex.

The aims of this work were to analyze the effects of a chronic (14 days) increase in the functional demand imposed on the triceps brachii and to evaluate the changes of the cortical representation of forelimb to this increased activity. The activation of triceps brachii was obtained by the hindlimb unloading (HU) model. Electromyographic activity changed from a phasic to a tonic pattern. Response amplitude increased during the first days of hyperactivity and then stabilized at an intermediate level. A transient decrease (-13% to -36% on day 2) in the mean frequency of motor units was observed. Content in myosin heavy chain of muscle fibers showed a reduction in IIb+IIx fibers in HU rats, whereas IIa+IIx fibers were more numerous. Thus, fibers tend to be more resistant to fatigue. Taken together, these observations reveal a dual plastic process. First, the nervous system reacts immediately to an environmental change, and second it reorganizes its motor command to impose a pattern of activity that is more adapted to a postural function. The extent of the cortical forelimb representation was delimited by oxidase histochemistry. No differences were detectable between control and HU animals for the period corresponding to enlarged receptive fields in the HU condition. Our observation lends support to our hypothesis that activation patterns contribute to the maintenance of neuronal properties in the somatosensory cortex. Moreover, the new tonic pattern resulting from the long contact of the paw with the floor may contribute to the adaptation of the central control of motoneuronal activity.

Animals↗

PubMed2004

Putting a spin on the dorsal-ventral divide of the striatum.

Since its conception three decades ago, the idea that the striatum consists of a dorsal sensorimotor part and a ventral portion processing limbic information has sparked a quest for functional correlates and anatomical characteristics of the striatal divisions. But this classic dorsal-ventral distinction might not offer the best view of striatal function. Anatomy and neurophysiology show that the two striatal areas have the same basic structure and that sharp boundaries are absent. Behaviorally, a distinction between dorsolateral and ventromedial seems most valid, in accordance with a mediolateral functional zonation imposed on the striatum by its excitatory cortical, thalamic and amygdaloid inputs. Therefore, this review presents a synthesis between the dorsal-ventral distinction and the more mediolateral-oriented functional striatal gradient.

Animals↗

PubMedDate not supplied

Pragmatic ability and disability as emergent phenomena.

A holistic approach to pragmatic ability and disability is outlined which takes account both of the behaviour of individuals involved in the communicative process, and also of the underlying factors which contribute to such behaviour. Rather than being seen as resulting directly from a dysfunction in some kind of discrete pragmatic "module" or behavioural mechanism, pragmatic impairment and also normal pragmatic functioning are instead viewed as the emergent consequence of interactions between linguistic, cognitive and sensorimotor processes which take place both within and between individuals.

Adult↗

PubMed2005

Multisensory responses and receptive field properties of neurons in the substantia nigra and in the caudate nucleus.

The basal ganglia are widely regarded as structures involved in sensorimotor co-ordination, but little is known about the sensory background of their function. We publish here descriptions of the excitatory sensory responses and receptive field properties of the visual, auditory, somatosensory and multisensory caudate nucleus and substantia nigra pars reticulata neurons. Altogether 111 caudate nucleus and 124 substantia nigra sensory neurons were recorded in halothane-anaesthetized, immobilized, artificially ventilated cats. The sensory properties of the caudate and nigral neurons were found to be quite similar. A majority of the units were unimodal while a significant proportion of them were multisensory. The visual and the somatosensory modalities predominated for both nuclei. The sensory receptive fields were extremely large. The visual and auditory receptive fields covered the whole physically approachable sensory field and the somatosensory receptive fields covered the whole body surface of the animal. The receptive field properties of the multisensory caudate and nigral units were similar to those of the unimodal neurons. We observed no signs of retinotopical or somatotopical organization within the basal ganglia. The particular sensory receptive field properties, together with the significant number of multisensory neurons in the basal ganglia, suggest the existence of a multisensory pathway of presumably tectal origin involving the caudate nucleus and the substantia nigra that may serve for the sensory feedback of motor actions co-ordinated by the basal ganglia.

Acoustic Stimulation↗

PubMed2004

Aldose reductase inhibition by AS-3201 in sural nerve from patients with diabetic sensorimotor polyneuropathy.

OBJECTIVE: The primary purpose of this investigation was to determine whether AS-3201, a new aldose reductase inhibitor, penetrates the sural nerve and inhibits sorbitol and fructose accumulation in patients with diabetic sensorimotor polyneuropathy (DSP). An additional aim was to determine whether any changes in nerve function would manifest with AS-3201 therapy. RESEARCH DESIGN AND METHODS: Patients with mild to moderate DSP based on nerve conduction studies were randomized into one of three treatment groups in a double-blind fashion: placebo or AS-3201 at 5 or 20 mg/day. After 12 weeks of administration, the sural nerve was biopsied for measurement of sorbitol, fructose, and AS-3201. RESULTS: At baseline, no important clinical, electrophysiological, or laboratory differences were found between the three groups. The nerve sorbitol concentration of 3.14 x 10(-2) nmol/mg wet nerve in patients in the placebo group was inhibited by 65 and 84% in patients on AS-3201 at 5 and 20 mg/day, respectively (P < 0.001). Fructose levels were similarly inhibited. Sensory nerve conduction velocities improved by > or = 1 m/s (P < 0.05). CONCLUSIONS: AS-3201 penetrates the sural nerve and inhibits sorbitol accumulation in patients with DSP. Additional studies are needed to confirm the electrophysiological suggestion that AS-3201 delays progression or leads to regression of DSP.

Adolescent↗

PubMed2006

Unilateral pallidotomy produces motor deficits and excesses in rats.

PURPOSE: To better understand the behavioral effects of pallidotomy as a treatment for a range of movement disorders, including Parkinson's disease, chorea, and ballismus. In some cases, pallidotomy increases movement whereas in others it decreases unwanted motor behavior. METHOD: The present study investigated the effects of unilateral pallidotomy in rats with an otherwise healthy nervous system. Pallidotomized and sham lesion rats were evaluated on a battery of tests that measure sensorimotor behavior. RESULTS: Compared to sham lesion controls, pallidotomized rats showed motor deficits (forelimb placing; bracing) and excesses (locomotor behavior) as well as sensorimotor asymmetries (ipsilateral adhesive patch bias; increased contralateral foot faults). CONCLUSION: Motor deficits observed after pallidotomy were similar to those reported in previous research from this and other laboratories following damage to the nigrostriatal pathway or sensorimotor cortex. Motor excesses after pallidotomy are consistent with current theories of globus pallidus function. Taken together, these data suggest hypokinetic effects of pallidotomy may be related to fibers of passage (i.e. internal capsule), while hyperkinetic effects may be related to damage of pallidal cell bodies. These data may have important clinical implications because they suggest that regardless of the state of existing pathology, pallidotomy may create unwanted behavioral side effects.

Analysis of Variance↗

PubMed2001

Changes in motor cortex activation after recovery from spinal cord inflammation.

Diseases of the spinal cord are associated with reactive changes in cerebral cortex organization. Many studies in this area have examined spinal cord conditions not associated with recovery, making it difficult to consider the value of these cortical events in the restoration of neurological function. We studied patients with myelitis, a syndrome of transient spinal cord inflammation, in order to probe cortical changes that might contribute to recovery after disease of the spinal cord. Seven patients, each of whom showed improvement in hand motor function after a diagnosis of myelitis involving cervical spinal cord, were clinically evaluated then studied with functional MRI. During right and left index finger tapping, activation volumes were assessed in three cortical motor regions within each hemisphere. Results were compared with findings in nine control subjects. Compared to the control group, myelitis patients had larger activation volumes within contralateral sensorimotor as well as contralateral premotor cortex. The degree of daily hand use showed a significant correlation with the volume of activation in contralateral sensorimotor cortex. Recovery from myelitis is associated with an enlarged activation volume in contralateral motor cortices. This change in motor cortex function is related to behavioral experience, and thus may contribute to motor improvement. The expanded activation in motor cortex, seen with several forms of spinal cord insult may have maximal utility when corticospinal tract axons are preserved.

Adult↗

PubMed1999

The role of the posterior parietal cortex in human object recognition: a functional magnetic resonance imaging study.

The mechanisms involved in visual object recognition from non-canonical viewpoints were investigated using functional magnetic resonance imaging (fMRI). We used a passive observation task and found three areas activated more strongly in the non-canonical viewing condition compared with the canonical viewing condition. First, it was found that the fusiform gyrus and posterior part of the inferior temporal cortex were involved in the processing of shape information. Next, it was found that the posterior parietal cortex, mainly the superior parietal lobule and the ventral part of premotor area were involved in visuospatial processing and accessing sensorimotor knowledge. These results may indicate that recognition from non-canonical viewpoints is supported by using functional properties of the object, which require more real-time processing for object manipulation.

Adult↗

PubMed2005

Spinal effects of acupuncture stimulation assessed by proton density-weighted functional magnetic resonance imaging at 0.2 T.

Signal changes can be detected by proton density-weighted functional imaging in both the brain and the spinal cord. These are attributed to changes in extravascular water proton (signal enhancement by extravascular protons) density during neuronal activation. In this study, we used this technique to detect correlations between acupoint stimulation and neural activity in the spinal cord. Stimulation of acupoints associated with treatment of sensorimotor deficits (LI4 and LI11) was performed on 11 volunteers. During stimulation, 8 of the 11 subjects had consistent functional activations in C6/C7. A bilateral activation pattern was common. Our findings show that acupoint stimulation modulates activity in the spinal cord.

Acupuncture↗

PubMed1997

Brain functional activity during gait in normal subjects: a SPECT study.

The purpose of this study was to evaluate changes in brain activity during voluntary walking in normal subjects using technetium-99m-hexamethyl-propyleneamine oxime single photon emission computed tomography. This study included 14 normal subjects. Statistical parametric mapping analysis revealed that the supplementary motor area, medial primary sensorimotor area, the striatum, the cerebellar vermis and the visual cortex were activated. These results suggested that the cerebral cortices controlling motor functions, visual cortex, basal ganglia and the cerebellum might be involved in the bipedal locomotor activities in humans.

Adult↗