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 109 records · Page 6Linked 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↗

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↗

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↗

PubMedDate not supplied

Behavioral and neurochemical sequelae in young rats of antenal hypoxia.

To test the hypothesis that perinatal hypoxia may have postnatal consequences via à vis learning memory, and neurochemical sequelae, we exposed pregnant Sprague-Dawley rats to 10.5% O2 for 4 h per day (0800-1200 h) or continuously from gestional day E15 to E20. On E20 we quantified ornithine decarboxylase activity and polyamine concentrations in fetal brain. We also conducted behavioral tests from postnatal day P3 to P110. Relatively mild antenatal hypoxia resulted in altered learning, memory, and delayed maturation of early developmental sensorimotor function. These behavioral changes disappeared at various postnatal ages, depending on the function. Perinatal hypoxia also altered the pharmacological response to dopaminergic drugs. In addition, antenatal hypoxia feminized a male nonreproductive sexual behavior, that of saccharin preference. Acute hypoxia also resulted in an increase in the enzyme ornithine decarboxylase and polyamines, which may affect brain development.

Animals↗

PubMed1989

Afferents and efferents of the vestibular nuclei: the necessity of context-specific interpretation.

A synopsis of physiological and anatomical results is presented that leads to the conclusion that experimental data have to be interpreted in a context meaningful for the system investigated. For example, since there is an obvious spatial relationship between semicircular canals and extraocular muscles, the interdependence between the three-neurone-arc circuitry, and vestibular and visual signals follows quite naturally from a common geometry inherent in the sensory and motor periphery. It is emphasized that signals related to compensatory eye movements have to be interpreted within a vestibular/eye muscle frame of reference. By the same argument, when dealing with the head-neck movement system, the appropriate reference frame will have to be applied to arrive at a meaningful interpretation of related sensorimotor functions. Thus, in general terms, each system has to be interpreted within its own meaningful biological context.

Animals↗

PubMed1987

An hypothesis about redundancy and reliability in the brains of higher species: analogies with genes, internal organs, and engineering systems.

The phenomena of behavioral resistance to massive brain damage and behavioral recovery from brain damage suggest there is redundancy in neural tissue. This paper uses basic concepts from probability theory and reliability engineering, as a first step toward more rigorously establishing the plausibility of the redundancy hypothesis. Exponential effects in the relevant formulas lead to results that are intuitively surprising. Thus, within a broad range of parametric assumptions related to lifespan and number of neurons or neural subsystems, it appears that the human brain may be at least twice as large as it would have to be for short-term survival. Simple reliability models suggest that redundancies are in parallel connections of smallest subsystems, such as individual neurons. Other implications of the basic formulas concern the relation between backed-up subsystem reliability and lifetime usage frequency for each subsystem, and the evolution of approximately equal allocation of lifetime reliability among components of a system. In addition, the paper briefly reviews more complex reliability engineering approaches. Redundancy as a reason for neural mass action is compared to other theoretical reasons for mass action in sensorimotor function and learning. Relationships of the present hypothesis to other theories of recovery from brain damage and to theories of regressive trophic phenomena in ontogeny are briefly discussed; it is suggested that as stages of ontogeny progress, both redundancy and flexibility in simpler behavioral functions are traded away for a larger, more differentiated repertoire of complex functions and memories.

Animals↗

PubMed1986

Dopamine in the lateral caudate-putamen of the rat is essential for somatosensory orientation.

The present study examined the possible localization of somatosensory orientation in the caudate-putamen (CP) of the rat. In the first experiment, 6-hydroxydopamine (6-OHDA) was injected into either the anterodorsal (AD), anteroventral (AV), posterodorsal (PD), or posteroventral (PV) CP. Only rats with PV-CP 6-OHDA injections showed impaired orientation scores. However, these PV injections often caused widespread CP dopamine (DA) depletions, and no specific CP region appeared to be particularly associated with somatosensory orientation. In the second experiment, multiple injections of 6-OHDA were directed toward the medial or lateral halves of the CP to assess their relative contributions directly. DA depletions confined to the lateral (but not medial) CP resulted in orientation deficits; these deficits were greater than would be predicted from the volume of CP/DA loss. Furthermore, the magnitude of the DA fluorescence loss in the lateral CP was more highly correlated with the orientation impairment than was the medial CP fluorescence loss. Thus the lateral CP contributes to sensorimotor functions to a greater extent than does the medial CP, but the volume of CP/DA depletion also appears important.

Animals↗

PubMed1991

Response-related deficits following unilateral lesions of the medial agranular cortex of the rat.

Rats with lesions of the medial agranular frontal cortex (AGm) were tested for sensorimotor function. Spatial response bias and reaction time to lateralized visual targets were recorded in an automated test of visual reaction time. The same rats were also tested for somatosensory capacity and on a skilled reaching task. In all tasks, there was an ipsilateral response bias but no evidence of sensory neglect. In the visual reaction time task, initiation time was lengthened bilaterally. These deficits may parallel the effects on motor function after unilateral frontal cortical lesioning in primates. The results support the hypothesis that rat AGm contains a homologue of primate secondary motor cortex.

Afferent Pathways↗