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N V Pasikova

Publications and source records attributed to N V Pasikova.

15 recordsLinked to original sources
PubMed2006

Acquisition of a conditioned avoidance reflex and morphometric characteristics of the sensorimotor cortex in rats subjected to social deprivation in early ontogenesis.

Male Wistar rats were subjected to social deprivation from day 22 to day 70 of postnatal development to form a group of isolants. Measures of learning of a passive avoidance and the results of training to active avoidance of painful electrical stimulation in these rats were significantly lower at age 110-120 days than in control rats. The characteristics of movement activity in isolants during training and testing, as well as in the open field test, probably resulted from their high levels of anxiety. Morphometric measurements of the numbers of neurons, satellite glial cells, and free glial cells in the sensorimotor area of the neocortex showed that isolants had a significantly lower density of neural elements per unit area, which resulted from a decrease in the afferent flow due to social isolation.

Age Factors↗
PubMed2005

The temperature sensitivity of the cholinergic responses of cortical neurons in the guinea pig brain.

Studies on slices of the parietal cortex of the guinea-pig brain showed that a change in temperature from 20 degrees C to 36 degrees C led to increases in responses to microintophoretic application of acetylcholine to individual nerve cells. The greatest changes occurred over two temperature ranges: 27-29 degrees C and 34-36 degrees C. Increases in the cholinergic response were accompanied by increases in the spontaneous activity of the neurons.

Acetylcholine↗
PubMed2004

Intracortical synchronization of epileptic discharges at different stages of ultrastructural rearrangements in a completely neuronally isolated area of rat neocortex.

Cross-correlation functions were used to study the time delay (a measure of synchronization) in the appearance of epileptic discharges in distant areas of the cortex in the intact cortex and in neuronally isolated cortical strips in Wistar rats. Experiments were performed at different stages of axon sprouting 30 and 90 days after isolation of cortical areas and in intact cortex. Significant increases in the number of synapses in layer V of isolated cortical strips at 30 days correlated with significant decreases in the time delay, while decreases in the number of synapses at 90 days correlated with a significant increase in the time delay. This is evidence that newly formed synapses increase the extent of synchronization and thus affect epileptogenesis. The data obtained here suggest that large pyramidal cells in layer V of the rat neocortex form a neural network in pathological conditions, this supporting intracortical synchronization of epileptic discharges.

Animals↗
PubMed2004

[Temperature sensitivity of the cholinergic response in cortical neurons of guinea pigs].

A temperature change from 20 to 36 degrees C results in a significant increase of neuronal responses to iontophoretic application of acetylcholine in parietal cortex slices. The most intensive changes in cholinergic responses occurred in two temperature zones: 27-29 degrees C and 34-36 degrees C. Increase in the responses to acetylcholine accompany with increasing spontaneous spike activity.

Acetylcholine↗
PubMed2000

[Structural basis of the intracortical synchronization of epileptic potentials in the sensomotor region of the rat neocortex].

In control rats, penicillin-induced epileptiform discharges were completely synchronous in the neocortex sites at a distance of up to 4 mm from each other. Number of the cells decreased by 45.5% during 90 days in isolated cortical slabs and the synchronisation disappeared. The data obtained show that the loss of large pyramidal neurones of the layer V entailed a loss of the spatial synchronisation. The main axonal collaterals of large pyramidal neurones of the layer V could be followed horizontally for a distance of up to 2 mm in the somatosensory cortex. The neuronal network formed by the large pyramidal neurones of the layer V seems to provide a spatial synchronisation in the neocortex.

Animals↗
PubMedDate not supplied

Structural bases of intracortical processes underlying the synchronization of epileptic potentials in the sensorimotor areas of the neocortex in rats.

Studies in long-term isolated areas of the rat neocortex were performed to investigate the dynamics of the numbers and areas of nerve cell bodies in layer V and to compare these data with the degree of synchronization of epileptic discharges evoked by application of penicillin. Decreases in the number of pyramidal neurons with body areas of 200-350 microm2 in isolated strips after maintenance for 30 and 90 days led to decreases in the degree of synchronization of epileptiform potentials. Large pyramidal neurons are known to have long horizontal axon collaterals, spreading into layers V and VI of the neocortex. It is suggested that the neural networks formed by large pyramidal neurons by means of their long horizontal collaterals mediate the process of intracortical synchronization.

Animals↗
PubMedDate not supplied

[An improved method for isolating a section of the rat neocortex].

Neocortical island chronically isolated from surrounding cortical and subcortical structures with preserved pial blood supply has long been a model for research into the mechanisms of cortex functioning. To fully cut the cortex we improved the type of knife by using a retractable tungsten wire. The tip of a syringe needle was bent and cut away all but the beginning of the bend. In anesthetized rats the somatosensory cortex was exposed, the guide needle was lowered down to the desired depth into the cortex avoiding blood vessels. The wire then was pulled out through the curved needle tip until the tip of the wire touched the pia mater. The device was then raised, lowered, rotated to achieve complete separation of the cortical island from the surrounding tissues. The wire was retracted into the needle before withdrawal of the device. Analysis of neocortical slices 8 weeks later showed lesions of the white matter and transcortical cuts.

Animals↗
PubMedDate not supplied

[Simulation of local cerebral hemorrhage in different brain structures of experimental animals].

A standardized experimental model of intracerebral hemorrhagic stroke in small laboratory animals is developed and advanced for chronic neurobiological studies of normal and pathological higher nervous activity as well as disorders developed after acute hemorrhages. A device is advanced which allows a researcher to destroy appropriate brain structures (tissues and local blood vessels) with necessary precision by four-six rotations of curved stereotaxically inserted mandrel-wire knife and, subsequently, to inject autoblood into the area of the lesion. The advanced model is convenient for the reproduction of lesions in different brain regions (for the purpose of experimental knockouts) in neurophysiological, neuropharmacological, and clinical investigations.

Animals↗
PubMedDate not supplied

[A comparative study of antistroke activity of the new drug "cerebral" and its fractions in rats].

The effect of the new drug "cerebral" and its fractions 1-3 on the model of bilateral hemorrhagic stroke in white rats was studied with reference to the action of cebrolysin and cerebrolysate-M. With respect to the general functional state, behavioral activity restoration, and morphological data, the most pronounced antistroke action was observed for the cerebral-1 fraction. This fraction was further separated into three subfractions. The most promising test results were obtained for the 1.2 subfraction, which was selected for the further investigation.

Administration, Intranasal↗
PubMedDate not supplied

[Avoidance conditioning and morphometric characteristics of the sensorimotor cortex of rats exposed to social deprivation in early ontogeny].

Male Wistar rats were exposed to social deprivation in the period from the 22nd to 70th days of postnatal development. The characteristics of the learning of these rats at the age 110-120 days in the passive avoidance box and during training for active avoidance of electroshock were significant lower than those of control animals. Features of motor activities of the "isolants" in learning and testing, and in the "open field" may be related to their higher anxiety level. Morfometric studies of neurons and glial cells and neocortex thickness showed that significantly lower density of neural elements may be the result of the afferent sensory input limitation produced by the social deprivation.

Animals↗