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Results for “EXTRAPYRAMIDAL TRACTS”

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At least 937 records · Page 52Linked to original sources
PubMed1986

[Effect of stimulation of the superior colliculi of the tectum mesencephali on the motor neurons of the neck muscles of the cat].

Postsynaptic potentials evoked by stimulation of three points of the superior colliculus in motoneurons of neck muscles were studied in experiments on cats under chloralosenembutal anesthesia. Stimulation of ipsilateral superior colliculus evoked EPSP with latencies ranging from 1.5 to 3.5 ms in 49 motoneurons. Stimulation of contralateral superior colliculus evoked EPSP with latencies ranging from 1.5 to 3.0 ms in 63 motoneurons and IPSP with latencies ranging from 2.6 to 5.0 ms in 10 motoneurons. It is suggested that the recorded postsynaptic potentials are mono- and disynaptic.

Animals↗
PubMed1987

GABA receptor agonists and extrapyramidal motor function: therapeutic implications for Parkinson's disease.

GABA receptor agonists display a dual action on DA-mediated events. One includes a decrease in DA release, reduction in DA receptor density, and decreased response of postsynaptic cells to dopaminergic stimulation; it results in antidopaminergic effects. The other consists of a reduction of striatal cholinergic activity resulting in a facilitation of dopaminergic effects. These two effects could be dissociated depending on the dose of GABA receptor agonists. This dual action probably explains the results of clinical trials showing either amelioration of parkinsonian symptoms with aggravation of L-DOPA-induced dyskinesia or improvement of dyskinesia without or with aggravation of parkinsonian symptoms.

Acetylcholine↗
PubMed1987

[Intracellular study of the formation of new synapses and collateral sprouting of red nucleus neurons after destruction of the cerebellar nucleus interpositus in the adult cat].

Responses of red nucleus neurons to stimulation of ipsilateral cerebellar nucleus interpositus were studied in cats after lesion of contralateral cerebellar nucleus interpositus within the period ranging from two weeks to one year and seven weeks. Recording of fast and slow mono- and polysynaptic EPSPs showed collateral sprouting of axons of interposito-rubral neurons to occur in various parts of soma-dendritic membrane of rubro-spinal neurons. Stimulation of ipsilateral cerebellar nucleus interpositus evoked antidromic activation in many red nucleus neurons, suggesting the sprouting of axon collaterals from rubro-spinal neurons onto the neurons of ipsilateral cerebellar n. interpositus projecting to the red nucleus.

Animals↗
PubMed1986

[Descending pathways of the cerebral cortex to nuclear structures of the extrapyramidal system].

The connections of the neocortical structures in animal and human brains with the complex of nuclear formations of the extrapyramidal system have been studied. The authors present comparative characteristics and distribution of these connections in the nuclear and other formations of the extrapyramidal system. Both mediator (via the thalamus) and direct cortical projections toward the nuclei of the extrapyramidal system in primates, especially in humans, have been found to increase. It has been shown that the frontal cortex has closer connections with the complex of the extrapyramidal nuclei as compared with other brain lobes.

Adult↗
PubMed1985

Effects of chronic zimelidine and ethanol on psychomotor performance.

Twelve healthy men between 22 and 27 years of age participated in an experiment on interactions between zimelidine and ethanol. Zimelidine, 200 mg/24 hours, was administered for 10 days and ethanol, 0.5 and 1.0 g/kg of body weight, or placebo drinks were administered either with placebo capsules or on the last 3 days of zimelidine treatment. A battery of tests measuring skilled performance was used. The higher dose of ethanol increased plasma zimelidine and norzimelidine concentrations. Ethanol impaired standing steadiness, tracking, and one aspect of verbal information processing. Zimelidine improved tracking. No significant pharmacodynamic ethanol-zimelidine interactions were observed.

Adult↗
PubMed1987

Neuropharmacology of the extrapyramidal system.

The neuropharmacology and neuroanatomy of the extrapyramidal system are complex; however, in its most reductionistic state, this system is often described as a balance between the actions of dopamine and acetylcholine. In this paper, a thorough investigation of the neuroanatomy and neuropharmacology of the extrapyramidal system is undertaken, and an attempt is made to delineate the roles of other neurotransmitters and neuromodulators that play an important role in its functioning. To demonstrate the therapeutic complexity of extrapyramidal system movement disorders, clinical literature is briefly reviewed to show the relative efficacies of anticholinergic and prodopaminergic antiparkinsonian agents in treating neuroleptic-induced extrapyramidal side effects and to show how drugs that affect alternative neurotransmitter systems have also been used to treat these same side effects.

Acetylcholine↗
PubMedDate not supplied

[Structural-functional connections of the lemniscus system with the caudate nucleus in the cat].

Afferent projections were studied of nuclei of the spinal cord dorsal columns to the caudate nuclei. Evoked potentials (EPs) were recorded in the caudate nuclei and the nuclei of dorsal columns of the spinal cord to stimulation of the forelimb against the background and after unilateral elimination of the medial lemniscus. After the section, the EPs in the recorded nuclei sharply intensified in response to stimulation of the forelimb, ipsilateral to the section. Degenerative changes were also shown by electron microscopy in axonal terminals in the caudate nuclei at the operated side. Conclusion is drawn that the caudate nuclei receive direct connections from the contralateral nuclei of the spinal cord dorsal columns, which probably, conduct mainly kinesthetic afferent influences.

Afferent Pathways↗
PubMed1987

[Extrapyramidal syndrome in idiopathic hemochromatosis. Significance of laboratory chemical, neurophysiologic and imaging procedures (CCT, MRT)].

In any patient with unexplained basal ganglia symptoms or dementia, the possibility of idiopathic hemochromatosis (IHC) should be considered. The findings of magnetic resonance tomography, discussed in this case report, lead to the conclusion that IHC is very likely to induce these syndromes. This is of clinical importance as IHC can be successfully treated by phlebotomy.

Aged↗
PubMed1986

[Activity of neurons of the motor-sensory cortex of the cat during natural walking on the rungs of a horizontal ladder].

During locomotion on a flat surface and walking on crosspieces of a horizontal ladder the activity of 56 motor cortex neurons in the cat (5 identified cortico-spinal and 6 cortico-rubral neurons among them) was modulated in the rhythm of steps, i.e. it increased in one phase of a step and decreased in the other. The results of complication of locomotion task by the necessity of putting paws right on the support (fulcrum) while walking on the horizontal ladder were as follows: an increase of average activity of 19 neurons by 60 +/- 8% and a decrease of average activity of 19 neurons by 29 +/- 4%; growth of the modulation depth of 41 neurons (5 cortico-spinal and 6 cortico-rubral neurons) on the average by 68 +/- 19% for CS, 34 +/- 18% for CR and 36 +/- 5% for nonidentified neurons; temporary distribution of activity of 88% neurons in the step cycle while walking on the crosspieces of a horizontal ladder was that of walking on the flat surface.

Animals↗
PubMed1986

[Structural basis of the cortical regulation of movement].

The author analyzes his own and literature data about a wide-scale presentation of motor functions in the cerebral cortex, about the structure of sensomotor area, overlapping of the cortical zones of movements and sensitivity, efferent supraspinal motor routes and subcortical motor formations of the brain at different levels and some aspects of the cortical regulation of the structures in health and disease. The concept of analyzers seems to be a promising approach to studies of the motor regulation system, particularly to generalization of the findings obtained heretofore; the structure of the cortical end of the motor analyzer is described.

Brain Mapping↗