PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Electrodes, Implanted”

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 37 records · Page 2Linked to original sources
PubMed1975

[A modified method for the determination of locations of chronically implanted electrodes in rabbit brains (author's transl)].

A fast and simple method is described for the localisation of tips of chronically implanted electrodes in the brain of rabbits which may be obtained--under standard conditions--by an intra-aortal injection of a 2% potassium-hexacyanoferrate-III solution. This method also facilitates histological preparations with a thickness of 5 mu only and thus permits a thorough morpho-pathological examination not only in the area of the electrode tips but in adjacent zones as well. The use of a buffered formalin solution also permits certain histochemical examinations to be made, for instance the determination of nucleic acids.

Animals↗
PubMed1976

[A time-saving method for histo-enzymatic studies of brain tissues of animals with chronically implanted electrodes by means of a hard-section microtome (author's transl)].

A time-saving method is described for the localisation of chronically implanted electrodes in the brain of test animals by means of a "Kryostat" hard section microtome which allows both histo-topographic and histo-enzymatic investigations. This is made possible by the incorporation of a three-dimensional microtome holder.

Animals↗
PubMed1975

Histochemistry of trauma after electrode implantation and stimulation in the hippocampus.

Electrodes were implanted into the rat hippocampus in both hemispheres for increasing periods of up to 60 days, and the effects of trauma and electrical stimulation of enzymes controlling cell metabolism in the region of implantation were examined and assessed in relation to studies on humans. In the unstimulated hippocampus as a control, enzyme changes were mainly confined to a narrow area of tissue damage surrounding the electrode. The enzyme changes in response to trauma varied widely; some enzymes controlling tissue respiration showed early and rapid changes, increasing in hyperactive, swollen glial cells and vascular endothelium and decreasing in nerve cells and neuropile. Acid phosphatase activity also increased rapidly in glial cells; other phosphate-releasing enzymes increased more gradually with time. A turning point in these chages was apparent between 25 and 40 days, followed by a reversion to more normal levels at 60 days. Electrical stimulation of the hippocampus in the contralateral hemisphere produced no detectable enzyme changes from those of the unstimulated hippocampus.

Acetylcholinesterase↗
PubMed1978

Study of the motility of the avian oviduct with chronically implanted electrodes.

Electrical activity was recorded in conscious hens from chronically implanted electrodes in the smooth muscle layers of the oviduct. Transport of the egg through the magnum resulted from an inhibition of the electrical activity in the oviduct cranial to the egg and an increased spiking activity caudally. During an ovulatory cycle the progression of the egg was related to four different patterns of the uterine motility: within a sequence, the ovulatory cycles varied according to the duration of Phases 3 and 4.

Action Potentials↗
PubMedDate not supplied

Experience with implanted electrodes at Rancho Los Amigos Hospital.

Implanted units, manufactured by Medtronic, Inc., have been implanted in 31 patients for treatment of drop-foot. The principal problem encountered in this series is inflammatory reaction, which was observed in 7 patients and was serious enough in 5 to require removal. Theree have been no failures of the implanted equipment for periods of up to 7.3 years, although there is currently a question in 1 patient. There has also been no documented damage to the nerve due to chronic stimulation. Fine wire electrodes have been implanted intraneurally in a series of animals and in 3 patients. Preliminary results look encouraging, and this approach seems to hold considerable promise for a new generation of electrode design.

Electric Stimulation Therapy↗
PubMed1977

An evaluation of per-scalar cochlear electrode implantation techniques. An histopathological study in cats.

This study was carried out to evaluate the effects of infection and trauma on the organ of Corti and spiral ganglion cells following per-scalar cochlear electrode implantations in cats. The results showed that the incidence of infection with a per-scalar electrode inserted through an opening made directly into the apical and middle turns is low, provided the procedure is carried out aseptically with an antibiotic cover. Trauma could also be kept to a minimum by inserting the electrode into the scala tympani, taking care to insert the electrode without applying force, and ensuring that the first insertion is the only one. Furthermore, the tip of the electrode should be blunt, and its diameter smaller than the width of the scala tympani. It was noted that damage to the organ of Corti, and loss of spiral ganglion cells only occurred as a local phenomenon, and its extent was related to the severity of the damage to the Reissner's and basilar membranes. The insertion of an electrode through the round window and along the scala tympani was not free of risk, as infection which led to a marked loss of spiral ganglion cells occurred, particularly in the basal turn. On the other hand when the size of the electrode was small in relation to the cross sectional area of the scala tympani, and it was not inserted far along the length of the basal turn, the evidence of trauma was minimal. Tissue reaction to the teflon-coated platinum electrode was also not observed.

Animals↗
PubMed1976

A new method for the electromagnetic optimization of stereotaxically implanted electrodes in the brain: preliminary results.

A method of optimizing the geometrical and electrical parameters of multielectrodes implanted in the brain is presented. The method should be valuable for the standardization of the implantation procedure. It bases on numerical solutions of the partial differential equations governing the electric potential. A description of the computer program developed is given, results pertaining to special cases are included, as well as other possible applications.

Brain Diseases↗
PubMed1976

Visually evoked potentials in cortical and subcortical brain structures of conscious rabbits with chronically implanted electrodes. Standardized normal values and the influence of some psychopharmacological agents on them.

By means of a modified and simplified surgical and implantation technique, standardized values for visually evoked potentials (EP) from 7 brain structures (caudate nucleus, posterior hypothalamus, mesencephalic reticular formation, intra-laminar thalamic nuclei, amygdala, dorsal hippocampus and visual cortex) are obtained. The importance of a careful selection of the animal material, constant test conditions and the selection of test parameters as a prerequisite for the assessment of psychotropic drugs is emphasized and discussed. As an example of the specific influence on visually evoked potentials in the above named brain structures, the effects of haloperidol and amytriptyline on latencies and amplitudes of the individual parameters of EPs are described. It is assumed that the method described can be of great assistance for investigation and classification of newly developed substances.

Amitriptyline↗