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Results for “sensorimotor function”

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At least 199 records · Page 11Linked to original sources

PubMed1987

Dopamine-rich grafts ameliorate whole body motor asymmetry and sensory neglect but not independent limb use in rats with 6-hydroxydopamine lesions.

The capacity of dopamine (DA)-rich embryonic grafts to influence performance in a skilled motor task has been assessed. In two separate experiments, unilateral 6-hydroxydopamine lesions of forebrain DA systems induced a neglect of the contralateral limb and an almost total preference for use of the ipsilateral limb when reaching through the bars of a cage for food pellets. If the food paw was restrained, either by a bracelet or by injection of a local anaesthetic, the lesioned rats would continue to make many reaching attempts with the contralateral paw, but on the great majority of these attempts they were unsuccessful in grasping or retrieving food. DA-rich grafts, reinnervating the denervated caudate-putamen, provided no detectable benefit to the lesioned rats, neither in reducing the ipsilateral bias in their side preference, nor in increasing their success when constrained to reaching with the contralateral limb. This failure to benefit from the grafts is not due to the grafts themselves not being viable, since the same rats showed substantial compensation of whole body motor asymmetries in spontaneous and drug-induced rotation, and a reduction of asymmetry in a battery of neurological tests of sensorimotor function. The results are discussed in terms of the degree of anatomical integration of the grafts into the host neural circuitry, and the neural organization necessary for the performance of different classes of behavior.

Animals↗

PubMed1989

Effects of ageing on the behavioural responses to dopamine agonists: decreased yawning and locomotion, but increased stereotypy.

Sensorimotor function and the behavioural responses to a range of doses of subcutaneous apomorphine were assessed in mature (6-8 months) and old (23-26 months) Sprague-Dawley rats of comparable weight. In addition, the locomotor activity response of 12-month-old and 24-month-old rats to continuous infusions (14 days by osmotic minipump) of a selective dopamine D2 agonist. (+)-4-propyl-9-hydroxynaphthoxazine (PHNO, 10 micrograms/h) was investigated. Measures of spontaneous locomotor activity and motor coordination revealed impairments in the aged animals. Low doses of apomorphine (10-50 micrograms/kg), which preferentially activate dopamine autoreceptors, induced yawning, chewing mouth movements and penile grooming. The frequency of yawning and duration of penile grooming were significantly decreased in the old animals. In contrast, 200 micrograms/kg of apomorphine induced stereotyped sniffing and licking or gnawing, and these responses were significantly increased in the aged animals. There was a 25% decrease in striatal dopamine levels in the aged animals in this experiment. PHNO increased the amplitude of the circadian rhythms in locomotor activity exhibited by mature rats, and daytime tolerance to the stimulant effects of PHNO was reversed by stress in these animals. Both of these effects were attenuated in the aged rats. These findings suggest that (1) the dopamine receptors mediating yawning and stereotypy have different anatomical locations (2) ageing is associated with decreased responsiveness to stimulation of dopamine autoreceptors, consequent upon the loss of dopaminergic nerve terminals, and (3) while the functional response to selective stimulation of postsynaptic D2 receptors decreases with age, the postsynaptic response to a mixed D1/D2 agonist increases.

Aging↗

PubMed1989

Binding of the neurotrophic peptide Org 2766 to rat spinal cord sections is affected by a sciatic nerve crush.

The binding of the neurotrophic peptide, [3H]Org 2766 (55 nM), to rat spinal cord sections was studied, employing quantitative autoradiography. The binding was unevenly distributed over spinal cord structures and was displaceable by non-labelled Org 2766 to a limited extent (35%). Binding could not be displaced by the opiate antagonist, naloxone, indicating that [3H]Org 2766 binding sites are distinct from opiate receptors. However, the exact nature of the binding sites remains to be elucidated. A marked left-right difference in [3H]Org 2766 binding in the dorsal horns of the spinal cord at level L2 was observed, 6 days after unilateral crush lesioning of the sciatic nerve. No such effect was found at level T10. After 28 days, when sensorimotor functioning had completely recovered, the [3H]Org 2766 binding pattern was comparable to that in sham-operated rats again. It is suggested that Org 2766 binds to axonal sprouts or glia in the dorsal horn of the spinal cord.

Adrenocorticotropic Hormone↗

PubMed1989

Estrogen administration increases neuronal responses to excitatory amino acids as a long-term effect.

Ongoing studies from this laboratory have demonstrated marked potentiating actions of the sex steroid 17 beta-estradiol (E2) on glutamate-induced excitation. In the present study, systemic injection of a physiological dose of E2 was demonstrated to augment significantly excitatory responses of cerebellar Purkinje (Pnj) cells to iontophoretic application of the specific excitatory amino acid (e.a.a.) agonists quisqualate and N-methyl-D-aspartate. Potentiation of e.a.a. responses was observed as rapidly as 5-10 min post E2, and was, in many cases, a persistent, non-decremental effect. These observed long-term actions of E2 may provide one mechanism for the activating effects of the steroid on sensorimotor function and seizure activity.

Action Potentials↗

PubMed1990

3-Acetylpyridine results in degeneration of the extrapyramidal and cerebellar motor systems: loss of the dorsolateral striatal dopamine innervation.

3-Acetylpyridine (3-AP) administration to rats results in degeneration of the dopamine (DA) innervation of the striatum as well as degeneration of the olivocerebellar system. We now report that administration of this pyridine neurotoxin results in a decrease in striatal DA concentration which is restricted to the dorsolateral aspects of the caudatoputamen. 3-AP treatment did not alter DA levels in the ventromedial striatum, the nucleus accumbens, or the anteromedial prefrontal cortex. Both 3-AP and another pyridine neurotoxin, 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP), potently inhibited in vitro MAOB activity and in contrast weakly inhibited MAOA activity. However, in vitro inhibition of MAOB by the selective inhibitor deprenyl did not prevent or attenuate 3-AP-induced striatal DA depletion. These data indicate that 3-AP administration to rats not only results in degeneration of the olivocerebellar system, but also effects degeneration of the DA innervation of the dorsolateral striatum, the striatal sector thought to subserve motoric and sensorimotor function. 3-AP-induced nigrostriatal degeneration differs from that elicited by MPTP in that the former is not prevented by deprenyl pretreatment. The 3-AP-induced degeneration of both extrapyramidal and cerebellar motor systems may offer insight into the mechanisms involved in degeneration of the two motor systems in certain strains of rodents (such as the Weaver mutant mouse), and suggests that the sequelae of administration of this pyridine may serve as a useful model for olivopontocerebellar atrophy-associated parkinsonism.

Animals↗

PubMed1982

An assessment of the state hypothesis of animal "hypnosis' through an analysis of neocortical and hippocampal EEG in spontaneously immobile and hypnotized rabbits.

Hippocampal and neocortical EEG was studied in spontaneously immobile rabbits and in immobilized rabbits, "animal hypnosis.' Neocortical low voltage fast activity (LVFA) and hippocampal rhythmical slow activity (RSA) occurred spontaneously and were elicited by sensory stimulation, eserine and brain stimulation in normally immobile and hypnotized animals. Atropine sulfate blocked the LVFA and RSA that occurred during spontaneous immobility and hypnosis but not the LVFA and RSA that occurred during movement. RSA was also recorded from both CAI and dentate gyrus generators of the hippocampus during both types of immobility. The results show that hypnotized rabbits have the same type II (atropine-sensitive) EEG that is found in spontaneously immobile rabbits. The presence of type II EEG during hypnosis and its sustained sensitivity to stimulation is compatible with the view that the EEG activity is not uncoupled from its normal behavioral correlates. Perhaps normal EEG during animal hypnosis allows normal sensorimotor functions. This may permit the possibility of escape from predators at opportune moments once the immobility has served its defensive function.

Animals↗

PubMed1992

Enhancement of regeneration by Org 2766 after nerve crush depends on the type of neural injury.

The neurotrophic effects of the adrenocorticotropin (ACTH)-(4-9) analog Org 2766 (Met(O2)-Glu-His-Phe-D-Lys-Phe) were studied in rats recovering from a sciatic nerve crush. Org 2766 (10 micrograms/rat s.c., every 48 h) increased the number of myelinated axons reinnervating a previously denervated sciatic nerve by 32% (P less than 0.01), as assessed 13 days after crush lesioning, and facilitated recovery of sensorimotor functioning by 14% (P = 0.05), as measured by foot withdrawal after stimulation of the footsole with hot air. However, these facilitating effects were only seen if the nerve was lesioned using forceps with grooved jaws and not if forceps were used with cross-hatched jaws. Endoneural tubes and Schwann cells of the sciatic nerve appeared to be better preserved after crushing with grooved rather than cross-hatched jaws. Our data indicate that the regeneration-enhancing effects of Org 2766 are dependent on the type of injury applied to the endoneurium and endoneural tubes of the sciatic nerve and suggest that endoneural tissue may mediate the neurotrophic properties of Org 2766.

Adrenocorticotropic Hormone↗

PubMed1989

Psychological and physiological characteristics of patients with severe idiopathic constipation.

This study prospectively evaluated psychological profiles and selected parameters of colonic and anorectal sensorimotor function in 25 consecutive patients who were referred for severe idiopathic constipation. Measurement of colonic transit of radiopaque markers divided patients into those with normal transit (n = 10) and those with slow transit (n = 15). As measured by the Hopkins Symptom Checklist, patients with normal transit constipation demonstrated significantly higher scores for psychological distress in the global symptoms index and nine clinical subscales than did those with slow transit constipation and gastrointestinal control subjects (n = 25). Both groups with constipation had decreased rectal sensation compared with controls but there was no relationship to rectal compliance or threshold of internal sphincter relaxation. There was also no relation between abnormalities of anorectal parameters, including expulsion dynamics, and psychological profiles in two groups. Measurement of colonic transit and psychological profiles in patients with severe idiopathic constipation identify two groups of patients with respect to possible pathogenesis of symptoms. Accordingly, different therapeutic approaches may be required, one behaviourally and psychologically based and the other focused on the possible modification of disordered colonic transit.

Adolescent↗

PubMed1977

Active avoidance in rats with unilateral hypothalamic and optic nerve lesions.

During the height of the contralateral sensorimotor deficit that follows unilateral hypothalamic lesions, rats demonstrate severe performance deficits when tested on a two-way active avoidance task which utilizes a visual conditioned stimulus. This deficit is observed whether or not the ipsilateral or contralateral optic nerve is sectioned in conjunction with the unilateral hypothalamic lesion. With the return of sensorimotor function contralateral to the lesion, animals that had been unable to avoid shock during their debillitated phase demonstrated significant savings when tested on the original task.

Animals↗

PubMed1993

Development of some early sensorimotor behaviors in sodium-restricted rats.

Rats exposed to low levels of dietary sodium throughout development exhibit reduced chorda tympani nerve taste responses to sodium stimuli during adulthood, apparently due to altered activity of some hormone(s) or growth factor(s) during early development. We were concerned that such an alternation in the activity of some humoral factor(s) could affect development globally. To test this possibility, we utilized a battery of morphological and behavioral measures in neonatal, sodium-restricted rats, expecting serious deficits to be reflected in altered onset and expression of these behaviors. As compared with control rat pups, preweanling sodium-restricted rat pups exhibited greatly diminished body weight gain and delayed acquisition of several morphological features. However, in terms of sensorimotor development, no significant differences between sodium-restricted and control rat pups were found. We interpret these results to indicate that despite significant somatic effects, sodium restriction may not influence the development of physical prowess or of early sensorimotor function in a global manner.

Animals↗

PubMed1996

Ventriculolumbar perfusion chemotherapy with methotrexate and cytosine arabinoside for meningeal carcinomatosis: a pilot study in 13 patients.

Thirteen patients with meningeal carcinomatosis were treated by ventriculolumbar perfusion using methotrexate (MTX) and cytosine arabinoside (Ara-C). MTX (10-30 mg) and Ara-C (40 mg) were infused at 8- to 12-hour intervals on six or nine occasions via an Ommaya reservoir placed in the lateral ventricle. Nine of thirteen patients had evaluable response (69% response rate with a mean survival of 8.8 months among responders) and ventriculolumbar perfusion therapy was effective in improving cerebral, cranial nerve, and spinal root signs and symptoms, especially sensorimotor disturbance in the lower limbs. Three of the six bedridden patients became ambulatory without assistance and two of the four patients who were walking with assistance became ambulatory without assistance. Urinary incontinence also markedly improved, except in one nonresponder. Lumbar cerebrospinal fluid parameters (cytological findings and tumor markers) also improved in association with the clinical improvement. Our pilot results were encouraging, especially the improvement of sensorimotor function in the lower limbs. However, the toxicity was unacceptable when compared with that of standard intrathecal chemotherapy. Thus, this therapy needs to be investigated further to establish the most appropriate drug doses and perfusate volume to reduce toxicity as well as determine its true efficacy in the treatment of meningeal carcinomatosis.

Adult↗

PubMed1986

Behavioral effects of centrally administered dynorphin and [D-ala2-D-leu] enkephalin (DADLE) in rats.

Dynorphin and [D-ala2-D-leu]enkephalin (DADLE) were administered directly into the cerebrolateral ventricles of rats and effects on various indices of sensorimotor function and retention of a passive avoidance task were measured. Dynorphin markedly suppressed exploratory motor activity and decreased responsiveness to an acoustic stimulus. Although increases in latency to respond to a noxious thermal stimulus were seen in rats after dynorphin, these changes were always associated with alterations in motor capacity. Injection of dynorphin immediately after a passive avoidance training trial had no significant effect on retention 1 week later. The physiological effects of DADLE were clearly different than those of dynorphin. DADLE produced a biphasic decrease followed by an increase in motor activity and an increased acoustic startle reactivity. DADLE had no effect on reactivity to a noxious thermal stimulus. Posttrial administration of DADLE significantly impaired retention of a step-through passive avoidance task 1 week after training. These data indicate different neurobiological roles for kappa and delta opiate receptors in the central nervous system.

Acoustic Stimulation↗

PubMed1986

Intrinsic 5HT-immunoreactive neurons in the spinal cord of the fetal non-human primate.

Serotonin (5HT) immunoreactive neurons were identified in the late-term fetal spinal cord of normal non-human primates. These neurons were distributed throughout the spinal cord, being concentrated in lamina X and the subjacent ventral median fissure, while their immunoreactive fibers and terminals innervated the zone surrounding the central canal and the ventral spinal artery. Even at this late fetal stage, the dorsal and ventral spinal gray matter was virtually devoid of any positive 5HT immunoreactivity, in contrast to that seen in the adult primate. These findings suggest that the intrinsic 5HT neurons of the primate during development may modulate CSF composition or provide cues for spinal cord differentiation rather than regulate sensorimotor functions as they do in the adult.

Animals↗

PubMed1994

The involvement of nucleus accumbens dopamine in appetitive and aversive motivation.

In recent years, considerable emphasis has been placed upon the putative role of nucleus accumbens dopamine systems in appetitive motivation and positive reinforcement. However, considerable evidence indicates that brain dopamine in general, and nucleus accumbens dopamine in particular, is involved in aspects of aversive motivation. Administration of dopamine antagonists or localized interference with nucleus accumbens dopamine systems has been shown to disrupt active avoidance behavior. In addition, accumbens dopamine release and metabolism is activated by a wide variety of stressful conditions. A review of the literature indicates that there are substantial similarities between the characteristics of dopaminergic involvement in appetitive and aversive motivation. There is conflicting evidence about the role of dopamine in emotion, and little evidence to suggest that the profound and consistent changes in instrumental behavior produced by interference with DA systems are due to direct dopaminergic mediation of positive affective responses such as hedonia. It is suggested that nucleus accumbens dopamine is involved in aspects of sensorimotor functions that are involved in both appetitive and aversive motivation.

Animals↗

PubMedDate not supplied

D-cycloserine, a novel cognitive enhancer, improves spatial memory in aged rats.

D-cycloserine, a partial agonist of the NMDA receptor-associated glycine site, can enhance cognition. The present experiment examines the behavioral effects of D-cycloserine on cognitive deficits in male Fischer-344 rats, 24 months old. Rats 24 months old (n = 42) received either vehicle or one of 3 doses of D-cycloserine prior to testing. Young rats, 4 months old (n = 13), received vehicle prior to testing. Place discrimination and repeated acquisition were tested in the water maze and a variety of sensorimotor tasks were given. Aging impaired performance in all tasks. D-cycloserine improved performance in place discrimination and repeated acquisition. No doses affected sensorimotor function. These results support the hypothesis that D-cycloserine has cognition enhancing properties and that it may be useful in treating disorders involving cognitive impairment.

Aging↗

PubMed1993

Surgical management of recurrent carpal tunnel syndrome.

An approach to the surgical management of recurrent carpal tunnel syndrome was evaluated in 30 patients with 35 involved wrists. This includes internal neurolysis of the median nerve and early post-operative mobilization of the wrist and fingers. The preferred surgical approach is through a second, more ulnar incision. Clinical assessment of sensorimotor function was converted into a numerical score ranging from zero (normal) to 9 (anaesthesia) and 10 (atrophy, severe). The average pre-operative score was mean 6.5 and median 7. At a mean follow-up of 23.5 months, the average post-operative score was mean 1.8 and median 0, a statistically significant improvement (P < 0.001).

Adult↗

PubMed1990

Selective neocortical and thalamic cell death in the gerbil after transient ischemia.

In animal models of transients ischemia, selective vulnerability and delayed neuronal death in the hippocampus have been extensively described. However, little is known about selective damage in the neocortex and the thalamus, even though deficits in sensorimotor function are common in humans surviving hypoxic/ischemic episodes. This study investigated the neurodegenerative effects of transient ischemia in the gerbil neocortex and thalamus with use of Cresyl Violet and silver impregnation staining methods. In addition, immunohistochemistry of an astrocyte-associated protein, glial fibrillary acidic protein, was used to assess the astrocytic response to ischemia. Pyramidal cells in layers 3 and 6 of somatosensory and auditory cortex were exceptionally sensitive to ischemia, whereas the neurons in layers 2, 4 and 5 were more resistant to ischemia. More pyramidal cells were killed in layer 3 than in layer 6. This bilaminar pattern of neuronal death developed after periods of ischemia ranging from 3 to 10 min and was identifiable at post-ischemic survival times of 6 h to one month. Somatodendritic argyrophilia in the neocortex was identified as early as 6-12 h after 5 min of ischemia. The greatest number of degenerating cortical neurons were stained two to four days after ischemia. With 10 min of ischemia, argyrophilic neurites and neurons were also found as early as 8 h after the occlusion. The most extensive damage was noted in the ventroposterior nucleus, the medial geniculate nucleus, and the intralaminar nuclei two to four days after ischemia. Thus, selective vulnerability and delayed neuronal death are evident in both the neocortex and the thalamus after transient ischemia. These regions need to be examined when considering the efficacy of potential neuroprotective drugs.

Animals↗

PubMed1990

Distribution of substance P-like immunoreactive fibres and terminals in the medulla oblongata of the human infant.

This study provides a detailed report of the distribution and density of substance P-like immunoreactive fibres and terminals within the human infant medulla. Seven brains with no signs of macroscopic alteration fixed usually within 24-48 h after death were used. Free floating transverse sections (50-60 microns) were then immunostained with a monoclonal antibody against substance P using the avidin-biotin-peroxidase technique. Morphologically three types of substance P-like immunoreactive fibres were observed: those with small varicosities of less than 1 micron, those with medium varicosities of 1-2 microns and those with large varicosities of 2-4 microns. Very dense substance P-like immunoreactivity was present within the spinal trigeminal nucleus, parts of the gracile and cuneate fasciculi and the paracommissural subnucleus of the solitary nucleus; dense substance P-like immunoreactivity was present within the dorsal nucleus of the vagus nerve, commissural, medial, dorsal, dorsolateral ventral and ventrolateral subnuclei of the solitary nuclear complex, parasolitary nucleus, raphe obscurus, inferior olivary complex (medial, dorsal, dorsomedial nuclei) and ventrolateral part of the dorsal reticular nucleus; moderate substance P-like immunoreactivity was present within the gelatinosus nucleus of the solitary tract, lateral reticular nucleus proper, intermediate reticular zone and parvocellular reticular nucleus; sparse substance P-like immunoreactivity was present within the hypoglossal nucleus, retroambigual nucleus and much of the reticular formation (dorsal, parvocellular, ventral gigantocellular, dorsal paragigantocellular nuclei): and very sparse substance P-like immunoreactivity was present within the nucleus ambiguus, medial vestibular nucleus and parts of the reticular formation (ventral, medial, gigantocellular, ventral gigantocellular, dorsal paragigantocellular nuclei). Substance P-like immunoreactivity was absent in the area postrema, intercalated nucleus, gracile and cuneate nuclei, in the epiolivary, subtrigeminal and parvocellular divisions of the lateral reticular nucleus, spinal vestibular nucleus, and in the solitary and pyramidal tracts. In several regions the substance P-like immunoreactive fibres formed distinct pericellular arrays around the somata and dendrites of neurons (hypoglossal nucleus, dorsal nucleus of the vagus nerve, retroambigual nucleus, intermediate reticular zone). The results indicate the high specificity of the localization of substance P in various structures of the brainstem and underline the presumed significance of this peptide in autonomic and sensorimotor functions of the brain.

Female↗