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Results for “Cortical Synchronization”

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At least 1,585 records · Page 88Linked to original sources
PubMed1978

[Annual rhythms in frequency of electroencephalographic patterns (author's transl)].

A series of electroencephalographic features were measured for about 11,500 patients from a clinical population, over a period of five years (1972 to 1976) and were documented using a standarized procedure. It could be shown that for males a definite yearly rhythm was present for the relative frequencies of alpha-type, partial beta-type, and low voltage EEGs, as well as for continuous and grouped dysrhythmias, the amplitudes of which were in the main 20--30% of the average. For females on the other hand, apart from grouped dysrhythmias, no such yearly rhythms could be proven, at the most such with a periodicity of between 14 and 16 months. The data often display trends that are more distinct than the rhythmicity and as such these should be taken into consideration when deciding upon the model used for statistical regression.

Alpha Rhythm↗
PubMedDate not supplied

The effect of apomorphine injection into caudate nucleus on electrical activity of some structures of the rabbit brain.

The studies were carried out on rabbits with chronically implanted electrodes and cannulas. Apomorphine, dopamine, or haloperidol were injected into the caudate nucleus of wakeful rabbits at a volume of 2 microliter. EEG was recorded from gyrus cinguli anterior, nucleus dorsalis raphe, and dorsal part of hippocampal formation. Apomorhine produced a dose-dependent desynchronization of EEG in the structure tested. This effect did not appear when dopaminergic receptors were blocked by previous systemic (1.2 mg/kg) or intracaudal (10microgram) injection of heloperidol.

Animals↗
PubMedDate not supplied

[Electrophysiologic correlates of habituation and conditioned reflex elaboration].

The average correlation coefficient between the EEG of different parts of the cortex gradually decreases as the rabbit is habituated to the experimental surroundings. Elaboration of an electo-defensive conditioned reflex leads to its enhancement which is replaced by a phase of temporary decrease, to be followed again by an enhancement of EEG correlation. The pronouncedness of theta-frequencies in the spectral and coherent functions behaves in a similar way. Successive changes of delta-activity level reveal no regularity.

Animals↗
PubMedDate not supplied

[Effect of phentolamine on the electroencephalogram and pulse activity of the cortical neurons].

In tests with vigilant immobilized and also urethan anesthetized rabbits the influence of intravenous injection of phentolamine (3--10 mg/kg) on the EEG waves parameters was studied. It is shown that within 45 to 75 minutes following introduction of phentolamine there is observed either shortening or elimination of the EEG activation reaction in response to stimulation of the sciatic nerve. The blocking effect of the intravenous administration of phentolamine is noted also by following dynamic changes in the discharge activity of single neurons.

Animals↗
PubMed1984

Pharmacological studies of mabuterol, a new selective beta 2-stimulant. III: Effects on the central nervous system, striated muscle and carbohydrate and lipid metabolism.

Effects of dl-1-(4-amino-3-chloro-5-trifluoromethyl-phenyl)-2-tert.-butylamino-etha nol hydrochloride (mabuterol) on the central nervous system, the striated muscle and the carbohydrate and lipid metabolism were investigated in comparison with those of isoprenaline and salbutamol. Mabuterol caused the following changes in behavior: increased touch response (10 mg/kg p.o.), decreased spontaneous movement and ptosis (30 and 100 mg/kg p.o., resp.), observed for 240-300 min. Mabuterol (5 mg/kg p.o. and 2.5 mg/kg s.c.) prolonged the sleeping time induced by hexobarbital Na, but not dose-dependently. Mabuterol depressed reactive movement at 80 mg/kg p.o. and 40 mg/kg s.c. in the rotarod test, at 160 mg/kg p.o. and 40 mg/kg s.c. in the traction test and at 200 mg/kg p.o. and 160 mg/kg s.c. in the inclined plane test in mice, whereas isoprenaline and salbutamol were almost ineffective. Analgesic activity of mabuterol was found in the acetic acid writhing test but not in the bradykinin-induced nociception test. An anticonvulsive effect was not observed. Mabuterol (10 mg/kg i.v.) produced a change in the spontaneous EEG of one of three rabbits, showing synchronization of cortical activity with sedation. Equipotent dose (i.v.) ratios of mabuterol to isoprenaline were 10.2, 30 and 133 in the depression of incomplete tetanic contraction of cat soleus muscle, hypotensive effect and tachycardia respectively, whereas neither indirect nor direct electrical stimulation induced contraction of diaphragm and gastrocnemius muscle was affected. Equipotent dose (s.c.) ratios of mabuterol to isoprenaline were 2.07, 4.64 and 3.21 in increasing plasma levels of glucose, lactic acid and free fatty acids respectively. Mabuterol caused no remarkable change in myocardial glycogen content.

Adrenergic beta-Agonists↗
PubMed1984

[Brain function and higher nervous activity].

Some actual problems of higher nervous activity have been analysed on the peculiarities of brain states in the course of different types of conditioning and reactivity of the nervous structures which depend on the brain state have been considered. A concept of brain state as a specific mechanism of each temporal connection forming during the learning process has been formulated for the first time. The authors suggest that the brain represents the dynamic system with changeable structure which reveals itself in multitude nervous set constellation during various types of activity. This concept is presented to be the theoretical basis for integral evaluation of functional capacities of central nervous system.

Animals↗
PubMedDate not supplied

[Effect of high altitude hypoxia on the human EEG].

The paper presents the results of the comparative study of the EEG at alpine altitudes (Tuya -- Ashu pass, 3200 m) and at low altitudes (City of Frunze, 760 m above the sea level). The dynamics of EEG changes at different stages of adaptation to hypoxia is also traced. The obtained data show that the alpine hypoxia produces a considerable intensification of the excitation processes in the cerebral cortex. Different sensitivity to the oxigen shortage has been found in the frontal-temporal parts of the right and the left hemispheres.

Adaptation, Physiological↗
PubMedDate not supplied

[Sleep and wakefulness in Callorhinus ursinus].

Sleep and wakefulness of northern fur seals were studied on three subadult bulls carrying the implanted electrodes for recording the electrocorticogram of the two hemispheres, the neck electromiogram, the electrooculogram and the electrocardiogram. The active wakefulness accounted for 32.0 +/- 5.3% of total recording time, the relaxed wakefulness -31.7 +/- 3.1%, the slow wave sleep -30.5 +/- 5.1% and the paradoxical sleep -5.8 +/- 0.9%. The sleep cycle averaged 22,6 +/- 1.2 minutes. Interhemispheric asymmetry of the ECoG slow waves was pronounced in all three animals. Different forms of the asymmetry occupied 15.0 +/- 0.7% of total recording time. Such interhemispheric asymmetry was found in pinnipeds for the first time, in this respect the northern fur seals differ from the Caspean seals but resemble the dolphins.

Animals↗