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A G Galashina

Publications and source records attributed to A G Galashina.

At least 19 recordsLinked to original sources
PubMed2006

Correlated activity of sensorimotor cortex neurons in the left and right hemispheres of the rabbit brain in immobilization catatonia.

Spike sequences extracted from multineuron activity from neurons in the sensorimotor cortex, and recorded simultaneously in the left and right hemispheres of the brains of rabbits in the state of immobilization catatonia ("animal hypnosis") and on recovery of animals from this state were analyzed. Cross-correlation analysis of spike flows revealed a temporal relationship between the appearance of neuron spikes in the left and right hemispheres; these were regarded as the mutual influences of these neurons on each other. The intensity of the influences of left hemisphere neurons on cells in the right brain was shown to change significantly in relation to baseline measures at all stages of the experiment and at all of the time points studied. The intensity of the influences of neurons in the right hemisphere on cells in the left hemisphere changed significantly only after animals recovered from the state of immobilization and over much more restricted time periods.

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PubMed2004

Structure of dependent relationships between neurons in the sensorimotor cortex of the left and right hemispheres in rabbits in immobilization catatonia.

Dependence in the activity of sensorimotor cortex neurons recorded simultaneously in the left and right hemispheres was detected in rabbits in baseline conditions, during the state of immobilization ("animal hypnosis"), and recovery of animals from this state. In baseline conditions, the total percentage of dependent relationships between close-lying (within 50 microm) neurons in the left hemisphere was significantly smaller than in the right hemisphere and did not change either in the state of immobilization or on recovery from it. The total percentage of dependent relationships between close-lying neurons in the right hemisphere decreased significantly during immobilization and returned to baseline levels on recovery from this state. The percentage of dependent relationships between distant (500 microm) neurons in immobilization, conversely, showed no change in the cortex of the right hemisphere, though it changed significantly in the cortex of the left hemisphere, returning to baseline values when the rabbits recovered from this state. Further analysis showed that this cortical interhemisphere asymmetry was based on the asymmetrical activity of individual neurons and small neuronal populations. Thus, changes in the structure of dependent relationships between neurons in microareas of the cortex of the left and macroareas of the cortex of the right hemisphere could be in different directions, while changes in microareas of the right hemisphere and macroareas of the left hemisphere were synergistic. Thus, asymmetry was detected at different levels of neuronal combinations (neuron pairs, micro- and macrogroups of neurons), which suggests mosaicism in neuron structure, which ultimately leads to overall functional asymmetry in "animal hypnosis." Some changes in the structure of dependent relationships between sensorimotor cortex neurons arising in "animal hypnosis" persisted or even became more marked after recovery of animals from this state.

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PubMed2003

Comparative analysis of the frequency of neuron spike activity in the sensorimotor cortex of the right and left hemispheres in conditions of immobilization catatonia in rabbits.

Multineuron activity was recorded from the sensorimotor cortex of the right and left hemispheres during immobilization catatonia in rabbits. The first session of immobilization of the animals was followed by changes in spike frequency in 47% of neurons in the sensorimotor cortex of the right hemisphere. Of these, 30% showed decreases in spike frequency and 17% showed increases. Spike frequency in the sensorimotor cortex of the left hemisphere changed in only 18% of cells, of which 13% showed decreases in spike frequency and 5% showed increases. The spike frequency of neighboring (recorded with the same electrode) neurons could change reciprocally. Differences in neuron activity in the two hemispheres were virtually absent after the second session of immobilization (several days after the first)--spike activity changed in 21% of neurons in the right hemisphere and 24% in the left hemisphere. The ratios of the numbers of neurons with increases and decreases in spike activity in "hypnosis" also became identical in the cortex of the right and left hemispheres. A hypothesis is proposed for the involvement of cortical neurons in the organization of "hypnosis-like" states.

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PubMed1988

[Functional interneuronal connections in the motor cortex of waking and anesthetized cats].

Neuronal interconnections in the motor cortex of alert and anesthetized cats were studied using the techniques of multiunit activity recording and cross-correlative histograms. The number of neuronal interconnections did not decrease in cortical microareas during the deepening of anesthesia, but their reconstruction and levelling of inputs and outputs of all microareas' cells occurred. During the reconstruction of interrelationships among functional microareas an activation occurred in the neurons which had been rather inert in the cortex of alert cats. The data obtained suggest differential participation of the cat motor cortex' neurons in information processing at the level of microareas.

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PubMed1988

[Multineuronal activity of the cerebral cortex in cats during nembutal anesthesia].

In chronic experiments on cats, the multiunit activity was studied under action of small doses of nembutal (15 mg/kg) in the motor cortex. A different sensitivity to nembutal was revealed in the cells. Simultaneous recording of the multiunit activity in two microareas (within 270 mu) revealed that the change of mean firing rate recorded with different electrodes was reciprocal in a number of cases. Bursts of discharges were synchronous in a certain anesthesia stage in neighbouring microareas but the distribution was different. Thus, the use of light nembutal narcosis allowed to differentiate specific changes of the multiunit activity from the changes elicited by general synchronizing effects.

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PubMed1985

Interneuronal relations within and between cortical areas during conditioning in cats.

Multiunit activity was chronically recorded in auditory, visual and motor cortex during classical conditioning and extinction. A statistical method for cross-correlation analysis of interneuronal relations was used. Plastic changes in cortical integrative function had spatial features and depended upon types of conditioning. Results suggest the spatial features in cortical cell integration in the trained-brain consisting of 3 categories of neuronal system organizations: microset, local and inter-regional. The first two are localized in a cortical projection region, whereas the third occupies cortical regions activated during conditioning. An evaluation of systemic activity in cortical neurons suggests specific organizations of cortical integrative functions in learning.

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PubMed1981

[Convergence and divergence of interneuronal functional connections].

Multiunit activity was recorded in the auditory and motor cortex of cats with implanted electrodes, impulses with highest and lowest amplitudes being isolated by means of an amplitude discriminator. Crossinterval histograms were obtained for two simultaneous records. Functional relationships between neurons under different electrodes were evaluated by statistical interdependence of isolated trains. In the auditory cortex, neurons with high amplitude spikes mainly produced connections of excitatory type whereas neurons with low amplitude spikes produced connections of inhibitory type. In the motor cortex neurons producing heterogenous effect were predominant.

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PubMed1981

Intraanalyzer conditioned reflex properties of two-way connections of cortical neurons in cats.

One of the principles in the formation of integrating activity of the brain appears to be a two-way character of neuronal connections. Forward and backward conditioned connections demonstrate the acquired properties of two-way relations in the cerebral cortex. Interneuronal cortical connections and their modification in conditioned reflex activity were studied in a alert cats with chronically implanted electrodes using a statistical method for analysis of two impulse flows. Multineuronal activity was recorded in the auditory cortex. All of the investigated neurons were divided into pairs according to their functional relations: (1) with two-way connections, (2) with one-way connections and (3) completely independent pairs. The functional interrelation in the cortical microarea, and between cortical microareas, were defined according to the space distribution of neuronal pairs. Elaboration of the motor conditioned reflex led to an intensification of two-way connections both in the cortical microarea and between remote neurons. Extinction of the conditioned reflex exerted almost no effect on the intensity of two-way connections, but considerably decreased the number of independent neuronal pairs at the expense of reduction in the number of one-way connections between cortical microareas. Thus, acquisition and extinction of the conditioned reflex were accompanied by intensive interconnected neuronal activity. The features of interneuronal connection properties during extinction inhibition were the attenuation of successive information transfer in cortical cells, which prevented the impulse activity from passing to effector pathways.

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PubMedDate not supplied

The temporal organization of the correlational association of neurons of the cat motor cortex.

The multineuronal activity was recorded in cats with a developed conditioned food-procuring reflex to time. Cross-correlation histograms were plotted on the basis of the impulse activity of individual neurons isolated from the multineuronal activity, and an analysis was made of the distribution in real time of the impulses constituting the peaks on these histograms. The secondary analysis of the histograms made it possible to identify the dynamics of the changes in the functional connections between neurons over the course of the phase of active waiting on the basis of the distribution of coupled impulses. It was demonstrated in simultaneously recorded neuronal pairs that the concentration of coupled impulses was observed at various moments in time. Neuronal pairs, the concentration of whose coupled impulses is found towards the end of the conditioned reflex interval, were noted; this is regarded as the manifestation of a conditioned reflex reaction at the level of interneuronal interaction.

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PubMedDate not supplied

The assessment of the strength of interaction between neurons of the motor cortex of the cat in a conditioned reflex to time.

The study was carried out in cats, with the recording of multineuronal activity of the motor cortex during the development of a conditioned reflex to time. The strength of the interaction between adjacent and remote neurons within a range of 0.5 mm was assessed. The dynamics of the strength of the interneuronal interaction did not correlate in the overwhelming majority of cases with the dynamics of the frequency of the impulse activity of the neurons under investigation. Changes in the strength of interaction between neurons separated from one another in a conditioned reflex (CR) to time were encountered more often than between adjacent neurons; this may serve as additional evidence in favor of the hypothesis of the more rigid structure of connections within microsystems and the greater plasticity of connections between microsystems.

Animals↗
PubMedDate not supplied

Features of the systemic organization of cortical neurons with different forms of the manifestation of a conditioned reflex to time.

A conditioned food-procuring reflex to time (2-min interval) was developed in cats. The coupled activity of neurons in microareas and between microareas of the motor cortex was compared by cross correlation analysis in different forms of the manifestations of the conditioned reflex: decrease in the amplitude of respiratory movements, increase in amplitude, and food-procuring movement of the paw for several seconds prior to the delivery of the reinforcement. Differences were manifested in the degree of increase in the number of functional associations in the second half of the interval as compared with the first, and, to a still greater degree, also in the frequency with which intervals were encountered with altered structure of the interrelationship between the neurons. The changes observed did not always correlate with the change in the frequency of impulse activity of individual neurons, which was noted substantially less frequently.

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