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At least 199 records · Page 11Linked to original sources
PubMed1998

Hemispheric control of motor function: a whole brain echo planar fMRI study.

The aim of this study was to explore whether recruitment of the ipsilateral motor cortex during non-dominant motor movement reflects left hemispheric control of motor function or simply the greater complexity or unfamiliarity of the motor task. BOLD fMRI was performed in normal right-handers during two motor tasks: (1) sequential finger movements (SM task) with the right or left hand; and (2) random finger movements (RM task) with the right hand. In all subjects, activation was predominantly in the contralateral motor areas (primary sensorimotor, lateral premotor, parietal and supplementary motor regions) and ipsilateral cerebellum. While the ipsilateral motor areas were also activated, single subject analysis revealed these areas to be more extensive and to be seen in more subjects during the non-dominant hand SM task and dominant hand RM task than during the more familiar dominant hand SM task. Similarly, group analysis also revealed ipsilateral activation in the primary sensorimotor and lateral premotor areas, but only during the non-dominant SM task and the dominant hand RM task. Non-dominant hand movements, perhaps because they are less 'automatic', appear to require more cortical activity similar to complex tasks with the dominant hand, and result in greater recruitment of ipsilateral cortical motor areas and striatum. The study also illustrates how potentially meaningful subtleties seen on individual maps may be obscured with group averaging approaches.

Adult↗
PubMed1988

Unilateral infusion of GABA and saline into the nucleus basalis of rats: 1. Effects on motor function and brain morphology.

Motor behavior was investigated in rats following acute and chronic gamma-aminobutyric acid (GABA) microinfusions into the nucleus basalis. For acute treatment, the rats received GABA (100 micrograms in 1 microliter), then saline, or these solutions in the reverse order, into the nucleus basalis contralateral to their preferred turning direction in a radial maze. For chronic treatment, half the rats received saline (1 microliter/h for 4 days), and than GABA (100 micrograms/microliters/h) for the same period of time ('saline-first' group). In the other half, this sequence was reversed ('GABA-first' group). Acute microinjections of GABA decreased turning towards the non-injected side; chronic treatment enhanced this effect by reversing the preferred turning direction. Return to initial turning direction was observed after acute GABA-injection in both experimental groups, but only in the 'saline-first' group after chronic treatment. The 'GABA-first' group showed gliosis in and around the nucleus basalis area and a reduction of cortical acetyl-cholinesterase-positivity which were significantly greater than in the 'saline-first' group. This, chronic saline pretreatment is associated with diminished neurotoxicity of chronic GABA infusion and with a reversibility of the drug-induced behavioral effects.

Animals↗
PubMed1988

Effect of stress on oesophageal motor function in normal subjects and in patients with the irritable bowel syndrome.

Stress can modulate the motor function of the stomach, small bowel, and colon in healthy subjects, and of the small bowel and colon in patients with the irritable bowel syndrome (IBS). The effect of stress on oesophageal motility in eight healthy subjects and in eight IBS patients was studied, using two pressure transducers positioned just above the lower oesophageal sphincter and 5 cm proximally. Stressors were: a video arcade game, delayed audio feedback, and hand immersion in cold water. Each stress period was followed by five swallows of water. Frequency and amplitude of oesophageal contractions and the number of simultaneous and multipeaked contractions were manually counted for each stress period and compared to the preceding rest period. Frequency of contractions (per minute) tended to decrease during stress periods, but achieved significance only with the video arcade game in the control group (2.0 (0.6) v 1.2 (0.4); p less than 0.01). No other trend was evident in either control or IBS patients. No abnormalities of oesophageal body function were recorded in IBS patients either in basal conditions, or under stress. Unlike the more complex motor programmes elsewhere in the gut, the preprogrammed nature of oesophageal peristalsis is not modulated by stress.

Adult↗
PubMed1991

The effects of 2,4-dithiobiuret on sensory and motor function.

2,4-Dithiobiuret (DTB) exposure causes a delayed onset muscle weakness in rats that has been attributed to depressed neuromuscular transmission. The present study compares the effects of DTB on both sensory and motor function in rats. Adult male Long-Evans hooded rats were exposed to saline, 0.25, 0.5, or 1.0 mg/kg/day DTB, ip, for 5 consecutive days (Days 1-5). Body weights were monitored throughout the experiment. Motor activity was measured for 1 hr in figure-eight mazes on Days 0, 6, 13, and 27. Forelimb and hindlimb grip strength were assessed on Days 6, 13, and 27. Auditory thresholds were determined for 5- and 40-kHz tones using reflex modification of the startle response on Days 0, 7, 14, and 28. Visual function was examined on Day 6 in animals exposed at 0.5 mg/kg/day using flash- and pattern-elicited visual evoked potentials (FEPs and PEPs, respectively). Thermal sensitivity was measured using the hot plate procedure. All motor endpoints were decreased in a dosage- and time-dependent manner; the higher the dosage the longer the effects lasted. There were no effects on any measure of sensory function with the exception of peak N2 of the FEP. Both the amplitude and latency of FEP N2 were altered by DTB exposure. Decreases in body weight were maximal on Day 9 at 1.0 mg/kg/day (20% from control), but recovered by Day 22. Motor activity was suppressed on Day 6 only, whereas grip strength measures were decreased on both Days 6 and 13. Auditory thresholds were not significantly altered; however, baseline startle amplitude was decreased at the highest dosage on Days 7 and 14, but recovered by Day 28. Hot plate latencies were not altered by DTB treatment. These data demonstrate that DTB produces a reversible impairment of motor function, without altering auditory, thermal, or pattern visual function. FEP N2, which is thought to arise from activity generated in the superficial layers of visual cortex, was diminished by DTB treatment, indicating that DTB can alter the function of the CNS, although effects on the motor system are more pronounced.

Animals↗
PubMed1987

Motor function in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mouse.

Motor function was assessed by use of a swim test in C57 Black mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Thirty minutes after the last MPTP injection significant motor impairment was observed while striatal dopamine was reduced to 13.9% of control levels. At 24 h and 7 days post MPTP injection dopamine levels were still reduced to 17.3% and 26.4% of control values but swimming abilities of the mice were unimpaired. Histofluorescence of catecholaminergic neurons confirmed the presence of catecholamine depletion but showed little evidence of neuronal destruction. The use of MPTP as a non-invasive means of nigrostriatal dopamine depletion in rodents and higher animals allows a re-evaluation of the role of the dopaminergic system in the modulation of movement.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1983

Aging and oral motor function: evidence for altered performance among older persons.

A physical examination procedure was used to evaluate oral motor functions in a population of 257 community-dwelling males and females ranging in age from 23-88 yr. An increased prevalence of altered motor performance with age was found for parameters measuring lip posture and masticatory muscle function. Also, males, but not females, showed a higher prevalence of alterations in tongue function and in swallowing.

Adult↗
PubMed1976

Management of children with non-organic (hysterical) disorders of motor function.

Five children aged between 10 and 13 years are discribed whose disorders of motor function were found to have a non-organic (hysterical) cause. In most cases extensive investigations had been made to establish an organic cause before the hysterical basis was diagnosed. The three essentials of management of such cases are to limit further investigations to the essential minimum, to institute quickly a programme of graduated physical rehabilitation, and to establish and treat the underlying psychological problems.

Adolescent↗
PubMed1981

Canine esophageal motor function: effects of arterial and intravenous vasopressin.

The effect of vasopressin infusion on esophageal motor function was evaluated in 11 anesthetized dogs. Gastric fundic, lower esophageal sphincteric, and esophageal body pressures were measured during and after 1 hr infusion of vasopressin into the superior mesenteric artery or a systemic vein. Lower esophageal sphincteric pressures started to decrease significantly 10-15 min after the start of vasopressin infusion, reached the lowest level at 45-60 min, and returned to the control level or higher 1 hr after the end of infusion. No statistically significant difference was found between the effects of intravenous and intraarterial vasopressin infusions. Esophageal body and gastric fundic pressures remained unchanged. The result is inconsistent with the hypothesis that esophageal smooth muscle contractions reduce esophageal variceal hemorrhage during vasopressin infusions.

Animals↗
PubMedDate not supplied

Cyclooxygenase inhibition in the dorsal vagal complex of the rat evokes increases in gastric motor function.

To characterize the involvement of brainstem cyclooxygenase (COX) in the vagal control of gastric motor function, tolmetin, a reversible COX inhibitor, was applied to the surface of the dorsal medulla oblongata or microinjected into the dorsal vagal complex (DVC) in alpha-chloralose anesthetized rats, while intragastric pressure and contractile activity of the pyloric circular and greater curvature longitudinal muscle were monitored. Tolmetin, applied to the surface of the medulla oblongata, increased intragastric pressure and stimulated contractile activity of gastric smooth muscle. Comparable gastric motor effects were observed after microinjection of tolmetin into the DVC. All the effects of tolmetin were abolished by bilateral vagotomy at the midcervical level. These results demonstrate for the first time that COX inhibition evokes vagally-mediated gastric motor effects in the DVC of the rat and support a role for COX products in gastrointestinal regulation.

Animals↗
PubMed1997

Distribution of nitric oxide synthase in rat dorsal vagal complex and effects of microinjection of nitric oxide compounds upon gastric motor function.

Nitric oxide (NO) has received attention as a vagal nonadrenergic-noncholinergic (NANC) mediator of gastrointestinal relaxation. The dorsal vagal complex (DVC) is the primary hindbrain site of vagal control of the gastrointestinal tract, and yet the subnuclear distribution of NO and its physiological effects have not been analyzed in this nucleus. Therefore, this study estimates the relative number of NO synthase (NOS)-containing neurons in subnuclear regions of the DVC, identifies NOS-containing vagal abdominal preganglionic neurons in the dorsal motor nucleus of the vagus, and defines a role of NO in the DVC in control of gastric motor function. The location of NADPH-diaphorase-positive staining (a marker of NOS activity) and NOS immunoreactivity overlap in the DVC. In the dorsal motor nucleus of the vagus there are positively stained cells caudal to the obex and at its most rostral extent, but not at the intermediate level. Intraperitoneal fluorogold combined with NADPH-diaphorase activity labels approximately 5% and 15% of fluorogold-immunoreactive cells in the caudal and rostral dorsal motor nucleus of the vagus, respectively. Thus, a portion of NOS-containing neurons are preganglionic vagal neurons projecting to the abdominal viscera. In the nucleus tractus solitarius, the majority of NADPH-diaphorase-positive cells are within the centralis, medial, and ventral/ventrolateral subnuclei. Fiber/terminal staining is present in the subnucleus centralis, subnucleus gelatinosus, subpostremal zone, and the medial nucleus tractus solitarius. The presence of NOS terminal staining implicates NO in afferent control of gastric function in the DVC (e.g., vago-vagal circuits in subnucleus gelatinosus). To determine a role of NO in the DVC, NO-related agents were microinjected into the DVC in alpha-chloralose-anesthetized rats while recording indices of gastric motor function. L-Arginine, microinjected into the DVC, significantly decreases intragastric pressure (-2.2 +/- 0.4 cm2, N = 12), and this effect is abolished by vagotomy. Microinjection of an NOS inhibitor, NG-nitro-L-arginine methyl ester, increases intragastric pressure (1.9 +/- 0.7 cm2, N = 10), with the greatest effect in the DVC rostral to the obex. Overall, it was concluded that tonic release of NO in the DVC mediates gastric relaxation, at least in anesthetized animals, and NOS-containing preganglionic neurons in the dorsal motor nucleus of the vagus may be "command" NANC neurons which control a variety of gastrointestinal functions.

Animals↗
PubMed1984

Common cortical and thalamic mechanisms for language and motor functions.

Evidence for common mechanisms in the human brain for motor and language functions is reviewed, particularly evidence derived from electrical-stimulation mapping during cortical and thalamic operations in awake patients. Several systems in the dominant hemisphere are identified where language and motor function share common mechanisms, including a lateral thalamic attentional system and a lateral perisylvian cortical system common to sequential movement and speech sound identification, where precise timing may be a common mechanism.

Cerebral Cortex↗
PubMed1998

Role of GABAA receptors in rat hindbrain nuclei controlling gastric motor function.

It has been shown in cats that gastric motor control by the dorsal vagal complex and nucleus ambiguus is under a tonic GABAergic influence. Since much more work has been performed in rats to define vago-vagal reflexes controlling gastrointestinal function, an understanding of the potential inhibition by candidate neurotransmitters such as GABA (gamma aminobutyric acid) in the rat dorsal vagal complex (DVC) is essential to assess. Multiple-barrelled micropipettes were used to apply to the dorsal vagal complex the GABAA antagonist, bicuculline methiodide (0.1-1 nmol), and a GABAA agonist, muscimol (10 nmol) prior to micro-injection of the GABAA antagonist. Micro-injections of bicuculline (353 pmol and 1 nmol), which were localized primarily in the dorsal motor nucleus of the vagus, produced significant increases in intragastric pressure and pyloric motility. These responses were abolished by vagotomy and by a prior micro-injection of muscimol. To determine whether GABAergic blockade in the dorsal vagal complex results in gastric motor excitation through excitatory amino acid receptors, kynurenic acid (5 nmol), a kainate/NMDA (N-methyl D-aspartic acid) receptor antagonist, was micro-injected prior to bicuculline. This abolished the increase in gastric motor function normally evoked by bicuculline. In the other two important hindbrain nuclei controlling gastric function, the nucleus raphe obscurus and nucleus ambiguus, bicuculline (353 pmol) significantly increased intragastric pressure via vagally mediated pathways. These data demonstrate that all three rat hindbrain nuclei known to influence gastric function via the vagus nerve are under tonic GABAergic control. In addition, in the dorsal vagal complex, relief from GABAergic inhibition results in increases in gastric motor function through kainate/NMDA receptor-mediated excitation.

Animals↗
PubMed1994

The influence of neonatal intensive care unit caregiving practices on motor functioning of preterm infants.

OBJECTIVES: Experimental design intervention studies have demonstrated that a model of individualized developmental care based on specific behavioral observation improves medical and behavioral outcome for very small preterm infants. It is proposed that infants who were not directly involved in an experimental intervention study per se, but were patients in a neonatal intensive care unit (NICU) where such studies took place and the model was adopted as the standard of care, demonstrate some of the same benefits as the infants in the experimental study. METHOD: The study was a retrospective descriptive analysis of an existing data set. The functioning of two cohorts of infants, comparable medically and demographically and cared for in an NICU where developmental care research was conducted and subsequently adopted as the standard of care, was measured after discharge with the Assessment of Preterm Infants' Behavior (APIB). Cohort I was cared for before the first study of individualized developmental care in the NICU; Cohort II was cared for after the individualized developmental care approach was adopted as the standard of care for the NICU. RESULTS: Cohort II infants demonstrated better scores than Cohort I infants on 8 out of 23 summary variables, 6 of which reflect improved motor functioning. They also showed significantly better scores on 7 of the 17 specific motor variables of the APIB. CONCLUSION: Infants cared for in an NICU with an individualized developmental care approach showed improved motor system functioning compared to infants cared for in the same NICU before the approach was adopted. It is speculated that the individualized developmental approach to care based in the synactive theory of development contributed to the documented improvements. This finding would indicate that functioning of preterm infants, particularly in terms of their motor systems, can be influenced by modification in caregiving.

Cohort Studies↗
PubMed1996

Modulation of human rhythmical jaw motor function by perioral argon laser stimuli.

The influence of peripheral afferent activity on human jaw motor function was examined in this study. Painful argon laser stimuli were applied to the upper lip in 10 subjects during rhythmical jaw movements and the effects on the jaw-closer electromyogram (EMG) and jaw movements were studied. The duration of the open-close cycle (1 sec) and the voluntary level of the jaw-closer EMG burst were standardized by auditory and visual feedback, respectively. Laser stimuli (0.2 sec) were delivered at predetermined percentages of the open-close cycle. Laser stimulation consistently had an excitatory effect on the jaw-closer EMG burst. The root-mean-square (RMS) value of the stimulus-related EMG burst was significantly larger than the preceding and the following EMG bursts. The excitatory effects on the jaw-closer EMG burst were modulated with respect to where in the open-close cycle the laser stimulus was applied, the voluntary force of the jaw-closer burst, and the laser stimulus intensity. Thus, the largest excitatory effects were seen during the start of jaw closure, with the most forceful voluntary contractions, and with the most painful laser stimuli. The stimulus-related changes in the jaw-closer EMG bursts were always associated with a significant shortening (30-90 msec) of the duration of the open-close cycle. The present results suggest that argon laser-induced activity in sensory afferents may generally have an excitatory effect on rhythmical jaw-closer motor performance.

Adult↗
PubMed1996

Oral motor function in the neonate.

The information in this article illustrates the importance of evaluating oral motor function of the infant, not only as function of his or her own ability but also of external and maternal assistance. The proper development of maternal behavior as a contribution toward the development of sucking behavior may not be readily evident; however, awareness is growing that a close mother-infant interaction can positively affect the infant's ability to feed, as well as his or her psychosomatic development. As a consequence, it becomes essential that the integrity of the nursing dyad be protected. More often than not, caretakers have seen the latter break down when mother or infant becomes too involved. Studies focusing on maternal and neonatal non-nutritional attributes stress the importance of acquiring a better appreciation of the psychosomatic benefits that can be generated by the nursing dyad. With such understanding, interventions may be developed to enhance the expression of these factors to help safeguard mother-infant relationship during difficult times.

Bottle Feeding↗
PubMed1988

Does healing of esophagitis improve esophageal motor function?

This study investigates whether healing of erosive esophagitis leads to an improvement of esophageal motor abnormalities. Manometric studies were performed in 18 patients with erosive esophagitis before and after healing of the mucosal lesions and in 15 healthy controls. Nine patients were treated with a Nissen fundoplication and nine with H2-receptor antagonists. After healing, patients were followed for a mean duration of 3.0 +/- 0.4 years. Compared to controls, patients had significantly lower contraction amplitudes and lower esophageal sphincter pressures (P less than 0.01), while the duration and velocity of esophageal contractions was similar in both groups. Lower esophageal sphincter pressure increased after surgical treatment, while no such changes were observed in medically treated patients. In both groups amplitude, duration, and velocity of esophageal contractions were not affected by healing of esophagitis. On extended follow-up, all surgically treated patients remained asymptomatic while eight of nine medically treated patients developed a symptomatic relapse which was accompanied by erosive esophagitis in six of them. The lack of improvement in esophageal motor function after healing of esophagitis may contribute to the frequent occurrence of relapse in medically treated patients.

Esophagitis, Peptic↗